United.States Industrial Environnterttol Research EPA-600/2-80-075b
Environmental Protection Laboratory April 1980
Agency .Research Triangle Park" NC27711
Research and Development
SERA
Assessment of
Atmospheric
from Petroleum Refining
Volume 2. Appendix A
; A-80-44
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EPA-60b/2-80-075b
April 1980
Assessment of Atmospheric
Emissions from Petroleum Refining:
Volume 2. Appendix A
by
R.G. Wetherold and C.D. Smith
Radian Corporation
P.O. Box 9948
Austin, Texas 78766
Contract No. 68-02-2147, Exhibit B
Program Element No. 1AB604
EPA Project Officer: Bruce A. Tichenor
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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DCN 30-219-144-47 .
ASSESSMENT OF
ATMOSPHERIC EMISSIONS
FROM PETROLEUM REFINING
VOLUME 2
APPENDIX A: METHODOLOGY
By:
RADIAN CORPORATION
Post Office Box 9948
8500 Shoal Creek Boulevard
Austin, Texas 78766
For:
Dr. Bruce Tichenor, Project Officer
Industrial Environmental Research Laboratory
Office of Research and Development
ENVIRONMENTAL PROTECTION AGENCY
Research Triangle Park, North Carolina 27711
EPA Contract No. 68-02-2147
Exhibit B
July 1980
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APPENDIX A: METHODOLOGY
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION L
2.0 FUGITIVE EMISSIONS 6
2. L Baggable Sources 6
2.1.1 Baggable Sources Selection 6
2.1.2 Screening 27
2.1.3 Sampling Train 48
2.1.4 Tent Construction 52
2.1.5 Sampling 62
2.2 Nonbaggable Sources 68
2.2.1 Nonbaggable Sampling Philosophy.. 68
2.2.2 Nonbaggable Source Sampling 69
3 . 0 STACK SAMPLING 75
3.1 Process Source (Stack) Sampling -
Sampling Trains 76
3.2 Stack Sampling Methods 77
3.2.1 Particulates 77
3.2.2 SOX 81
3.2.3 Aldehydes (A) and 81
Aldehydes (B) 83
3.2.4 HCN and NH3 83
3.2.5 Grab Samples 84
ii
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TABLE OF CONTENTS (Cont'd)
Section Page
4.0 SPECIES IDENTIFICATION 87
4.1 Sampling Strategy 87
4.1.1 Speciation Source Selection 87
4.1.2 Flue Gas Emissions 90
4.2 Sampling Methodology 90
4.2.1 Sorbents 90
4.2.2 Collection of Samples 99
4.2.3 Transportation and Storage 110
5. 0 FIELD ANALYSES 112
5.1 Mobile Laboratory. 112
5.2 Total Hydrocarbon Content (Methane/
Nonmethane) 114
5.2.1 Theory of Operation of a Flame
lonization Detector (FID) 115
5.2.2 Quantitative Analysis. . 120
5.2.3 Calculations 123
5. 3 Stack Effluent 125
5.3.1 EPA-5 Sampling Train Preparation. 125
5.3.2 Particulates Determination 127
5.3.3 Sulfur Oxides (SOX) 130
5.3.4 Nitrogen Oxides 138
5.3.5 Aldehydes 152
5.3.6 Ammonia 156
iii
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TABLE OF CONTENTS (cont'd)
Section Page
5.3.7 Hydrogen Cyanide 161
5.4 > Nonbaggable Sample Analyses 169
5.4.1 Oil 169
5.4.2 Water 170
5.4.3 Total Organic Carbon 173
6.0 SPECIES CHARACTERIZATION 174
6.1 Organic Species 174
6.1.1 Qualitative Analysis 174
6.1.2 Semi-Quantitative Analysis 189
6.2 Inorganic Species 190
7.0 CONVERSION FACTORS 191
REFERENCES - 192
IV
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LIST OF FIGURES
Figure Page
A2-1 Typical Valve Selection Format 19
A2-2 Typical Flange Selection Format 21
A2-3 Data Sheet - Valves 29
A2-4 Data Sheet - Pump Seal 30
A2-5 Data Sheet - Compressor Seal 31
A2-6 Data Sheet - Relief Valve 32
A2-7 Data Sheet - Flange or Weld 33
A2-8 Data Sheet - Unit Drain 34
A2-9 Gate Valves 44
A2-10 Plug Valves 45
A2-11 Sampling Train for Baggable Sources of
Hydrocarbon Emissions: Flow-Through Method
Using a Syringe 49
A2-12 Sampling Train for Baggable Source of
Hydrocarbon. Emissions Using a Diaphragm
Sampling Pump 50
A2-13 Mylar Plastic Sample Bag 53
A2-14 Tent Construction Around the Seal Area of
a Vertical Pump 54
A2-15 Data Sheet - Baggables and Tented Liquid
Leaks 64
A2-16 Mass Balance Around a Cooling Tower 73
A3-1 Method 5 Train for S02 and Particulates 78
A3-2 Aldehyde Impinger Train 79
A3-3 Grab Sample Collection and Preparation
System. . ~ 80
v
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LIST OF FIGURES (Cont'd)
Figure Page
A3-4 Refinery Inspection Trip - Refinery
Stack Facilities Summary 82
A4-1 Stainless Steel Glass-Lined Tenax-Silica
Gel Purge Traps 92
A4-2a Typical Sampling Train for Taking Gas Samples
on XAD-2 Resin Using the Blow-Through Method. 101
A4-2b Typical Sampling Train for Taking Gas Samples
. on Tenax Resin and Charcoal Using Blow-
Through Method , 102
A4-3a Typical Sampling Train for Taking Gas Samples .
on XAD-2 Resin Using the Flow-Through Method. 105
A4-3b Typical Sampling Train for Taking Gas Samples
on Tenax Resin and Charcoal Using the Flow-
Through Method. . . 106
A4-4 Source Assessment Sampling System 108
A4-5 XAD-2 Sorbent Trap Module. . . .. . . 109
A5-L Flame lonization Detector 116
A5-2 Area Response Versus Concentration 117
A5-3 Area Response Versus Molar Concentration 118
A5-4 Area Response Versus Weight Concentration.... 120
A5-5 Peak Height Versus ppraw 121
A5-6 Peak Area Versus ppmw Hydrocarbon 122
A5-7 Wastewater Purge Apparatus 171
A6-1 ABN Scheme 181
A6-2 Total and Selected Ion Current Plots
Obtained from the Analysis of An XAD-2
Sample Extract, Fraction 2 187
vi
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LIST OF TABLES
Table Page
A2-1 Range of Choice Variables for Screened
Baggable Sources 9
A2-2. Distribution of Valves Selected for
Maintenance Study in Each Refinery 25
A2-3 TLV Calibration Standards 36
A4-1 Speciation Samples - Process Streams 88
A4-2 Speciation Samples - Flue Gas Streams 89
A4-3 OSHA Standards and Sampling Procedures 94
A4-4 Nominal Operating Conditions for Sampling
With Adsorbents 100
A5-1 FID Relative Sensitivities 119
A6-1 Mass Spectrometers - Radian 175
A6-2 Summary of Sample Types and Analysis
Procedures 177
A6-3 Summary of Isolation Procedures 180
vii
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1.0 INTRODUCTION
The petroleum refining industry represents a major
potential source of hydrocarbon air emissions in the United
States. Petroleum is a natural product containing complex
organic substances, some of which are known to be toxic. There
is little recent information on the subject of refinery hydro-
carbon emissions and even less on the quantities and identities
of potentially toxic emissions. Uncontrolled or fugitive emis-
sions result from leaks which can occur in virtually any hydro-
carbon service. These emissions require specialized technology
for measurement.
In this program Radian has performed sampling and
characterization of fugitive hydrocarbon emissions from several
refineries. The methodology is described in subsequent sec-
tions of this appendix.
The first step in designating specific sources for
sampling was the choice of refineries. A rigorous sampling
plan would include most of the refineries known to be operating-
in the United States. Such a large sampling plan would be vir-
tually unmanageable as well as being cost-prohibitive. There-
fore, a number of representative refineries were selected for
sampling. Refinery age, size, and geographical location were
used as selection criteria.
t
Differences among refineries due to their different
geographical locations are seen primarily in the types of
hazardous materials they generate. Location influences the
quality of the crude oil processed, and the nature and rela-
tive quantities of the products manufactured. The latter
affects the severity of the operating conditions used in the
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process units as well as the types of units encountered. All
of these considerations affect the by-products that result
from processing the crude, and will influence the quantities
and types of atmospheric emissions.
It was not believed that location would have a direct
effect upon rates of hydrocarbon emissions. Knowledge of the
specific chemical species involved is not necessary for classi-
fication of overall leak rates from fugitive sources. A
possible secondary effect of location could include differences
in local regulatory philosophies.
It was decided that the location effect on hazardous
species would be investigated by sampling refineries in four
different geographical regions. These are:
East; Coast,
Gulf Coast,
West Coast, and
Middle United States (Midwest and
Mid-Continent).
Refinery Age and Size
Two of the principal parameters used in the selection
of refineries for sampling were age and size. These variables
affect such things as maintenance and degree of repair, quality
of equipment, and equipment design. Their use as independent
variables may not be entirely valid. A closer examination of
these factors is given in this section.
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There is no doubt that age affects the characteristics
of refinery equipment and might ultimately influence fugitive
emissions. There is some question, however, about the level at
which age becomes a significant variable. Various ages were
investigated at one of three levels of complexity: age of the
entire refinery, ages of individual process units and ages of
individual pieces of equipment.
Problems with this method exist in its application
to sampling and the utility of the data generated. Determina-
tion of the ages of various equipment pieces was difficult at
best. Turnaround and maintenance records for individual emis-
sions sources in each unit sampled were not available for the
most part.
Size
Refinery size can have an effect on such things as
the number and type of products manufactured, the number and
type of hazardous species formed, the types of units available
for sampling, the amount of effort put in on maintenance pro-
grams, and the quality of equipment purchased. The most
obvious break in these factors is between very small and large
refineries. In order to use size as some indication of com-
plexity, it was decided that a realistic cut point is 50,000'
bbl/day. A range of refinery sizes above and below this size
was sampled to prevent bias toward any individual size.
Because of the definition of size, size and refinery
or process age become interdependent variables. There are not
many new refineries significantly smaller than 50,000 bbl/day.
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Also, it is difficult to find many new process units in
refineries that small. Although the logical solution was to
pick hardware age as the variable, implementation would be
difficult if not impossible. Therefore, refinery age and size
was broken into three categories:
old/small,
old/large, and
new/large.
Large and small have been defined. Old means any
refinery having its oldest operating unit more than 20 years
old. New means having units no older than 20 years.
Process Units
The operating temperature and pressure were expected
to have major effects upon fugitive emissions from a source.
They.are classified as choice parameters. Many combinations
of temperature and pressure can be found in refineries. For
the purposes of this program, four pressure/temperature classi-
fications were employed:
high pressure/high temperature,
low pressure/high temperature,
high pressure/low temperature, and
* low pressure/low temperature.
These terms are defined as follows:
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pressure -
high > 150 psig
low < 150 psig, and
temperature -
high > 100° C,
low < 100° C.
A single unit usually did not have each size, type,
and service defined for each piece of hardware. The pressure/
temperature classification given to each unit reflected only
the operating conditions in its major equipment area, such as
a reactor. In some cases several units within a given category
were sampled to fill all of the required variable categories.
The choice of units was made on an individual refinery basis,
with as much diversity among units sampled as the differences
among refineries allowed. In this way, the effect of refinery
process and type on the rates and nature of emissions was
evaluated.
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2.0 FUGITIVE EMISSIONS
The methods developed for detecting fugitive
hydrocarbon emissions and measuring the emission rates are
described in this section of the appendix. The procedures for
selecting random sources for inspection and. measurement are
discussed.
2.1 Baggable Sources
Baggable sources have been defined as those sources
that can be completely enclosed and sealed in a manner suf-
ficient to prevent any loss of material to the atmosphere from
inside the enclosure or "bag." These sources represent the
majority of the potential sources selected for testing at each
refinery. They include valves, flanges, pump seals, compressor
seals, drains and relief devices.
2.1.1 Baggable Sources Selection
This section details the procedures by which indivi-
dual fugitive sources were selected for sampling. Selection
criteria are given for .choosing the refineries visited and
units sampled. The important, variables affecting baggable and
nonbaggable sources are presented and discussed.
In evaluating all the possible variables which could
affect fugitive emissions from refineries, it was useful to
categorize these variables into choice parameters and corre-
lating parameters. A choice parameter is defined as a variable
that is expected to directly affect fugitive emissions in such
a way that it should be set up as a category in planning the
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number of samples" taken. Establishing a good set of choice
parameters insures a statistically accurate sample.
All other factors which were thought to affect the
level of fugitive emissions were used as correlating parameters.
Pertinent information on each source sampled was recorded
during field testing. >
Baggable Source Selection - Important Variables
Variables thought to affect the fugitive emissions
from baggable sources were classified into choice and corre-
lating parameters. The variables were further defined accord-
ing to availability and usefulness. Availability was deter-
mined from the. degree of difficulty expected when obtaining
the necessary data in the field. Some information, such as
pressure or temperature, is readily available. Other facts,
such as age of valve packing, might be unavailable.
The final, usefulness of a variable in the computa-
tion of the fugitive emissions from a refinery was also con-
sidered. Some important variables were not categorized for
sampling because of their lack of ultimate usefulness. For
example, using the age of some equipment as a parameter may
not be very useful. Most refiners do not know the age of valve
packing or flange gaskets, for example.
The variables chosen for each type of fitting con-
sisted of the characteristics of the fluid within the fitting
and the physical characteristics of the fitting itself. Choice
parameters were defined as variables that might directly affect
fugitive emissions and were used in selecting the source
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distribution. The choice parameters used for each fitting type
are listed in Table A2-1 and discussed further below.
Valves
Valves are potentially the most significant source of
fugitive emissions in the modern refinery because of their
number. While individual leaks may be quite small, the cumu-
lative amount can be very high. There are many factors such
as valve construction, operating conditions, and fluid proper-
ties which may affect the magnitude of atmospheric emissions
from any given valve.
A distinction is made between in-line and open-end
valves. Most refinery valves are in closed piping systems. In
this situation, leakage around the valve seat would not enter
the atmosphere. The piping downstream of some valves is open
to the atmosphere, however. Examples of these are sample and
drain valves. Almost all sample and drain valves handle low-
temperature material, most are gate valves, most are installed
in pipes having diameters under four inches, and they are used
in block service. No further variable breakdown is needed to
describe these services.
More variables are required to characterize in-line
valves. Atmospheric emissions can. occur at three points in
these valves:
valve stem seals,
valve bonnet seals, and
valve end seals.
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TABLE A2-1.
RANGE OF CHOICE VARIABLES FOR SCREENED BAGGABLE
SOURCES
Baggable Source
Choice Variable
Variable Ranges Found
for Screened Sources
Valves
Pressure
Temperature
Fluid State
Service
Function
Size
-10 - 3,000 psig
-190 - 925°F
Gas, Liquid, 2-phase
In-line, Open-ended
Block, Throttling, Control
0.5 - 36 inches
Flanges
Pressure
Temperature
Fluid State
Service
Size
-14 - 3,000 psig
-30 - 9508F
Gas, Liquid, 2-phase
Pipe, Exchanger, Vessel,
Orifice
1-54 inches
Pump Seals
Pressure
Temperature
Capacity
Shaft Motion-
Seal Type
Liquid RVP
0 - 3,090 psig
0 - 800°F
0 - 100,000 gpm
Centrifugal, Reciprocating
Mechanical Seal, packed seal
Complete range
Compressor Seals
Pressure
Temperature
Shaft Motion
Seal Type
Lubrication Method
Capacity.
0 - 3,000 psig
40 - 300°F
Centrifugal, reciprocating
Packed, labyrinth, mechanical
Hydrocarbon lubricant
0.06 - 66.0 MMSCFD
Drains
Relief Valves
Service
Pressure
Temperature
Fluid
Active, Wash-up
0 - 1,350 psig
40 - 1,100°F
Gas, Liquid
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The valve stem seal is che primary source, since it must seal
against a moving stem. There are several varieties of bonnet
seals, but most refinery valves have a flanged bonnet seal.
These should leak less than stem seals since the seal assembly
is stationary. Valve end seals are made where the valve is
fastened to the adjacent piping. Most refinery valves have
flanged ends. These were sampled as flanges, and therefore
will be discussed in a later section.
The factors selected as choice parameters are
basically the same as those used on other fittings, i.e., size,
operating conditions (temperature, pressure), and fluid phase.
These are easily determined before sampling. One further .
choice parameter was applied uniquely to valves, that being
valve function. Each valve was classed as a block- valve or a
throttling valve. Throttling valves were normal hand valves or
automatically operated control valves. This parameter reflects
the effects of frequency of operation and type of stem movement.
Flanges
Flanges are the most common refinery example of the
larger set of pipe and vessel joints, which also include
threaded fittings and welds. Threaded fittings are limited to
small diameter low-pressure service, and thus are not a sig-
nificant portion of the refinery joint population. Welds are
almost as common as flanges, but are much less prone to leakage.
Welds are generally pressure-tested before being put into
service, and repaired if necessary. Once in service, the weld
is nearly as strong as the piping itself. A leak can result
from corrosion or erosion of the weld, but such a leak will
enlarge itself rapidly and become noticeable to unit personnel.
Failure of a weld in this manner is very serious. It would
10
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usually require immediate attention, because when one weld
fails, all others and the.; line itself become suspect. The
safety hazard dictates corrective action more strongly than
the pollution aspect. Therefore, no general program of weld
testing was conducted.
The flanges tested were divided into 16 categories,
depending on the interaction of three variables. These vari-
ables are:
size,
fluid state (gas/liquid), and
operating conditions (pressure/temperature).
The size of the flange was expected to be directly
related to the potential emissions because the effective seal
length is a function of the size. A variety of flange diame-
ters from two inches to four feet or more were tested to
quantify the leak rate/flange size relationship.
The fluid state has an obvious effect on the tendency
to leak. If a gap exists between the gasket and the flange
faces, the properties of the fluid within and the operating
conditions will determine the leak rate. The most obvious
division of fluid properties is into liquid or gas. Some
materials are transported under pressure as a liquid, but
emerge from a leak as a gas at ambient conditions. By
definition, the state inside the line was considered as the
characteristic state.
The operating conditions considered when categorizing
flanges were represented by the four pressure/temperature com-
binations described earlier:
11
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high pressure/high temperature,
high pressure/low temperature,
low pressure/high temperature, and
low pressure/low temperature.
These four rough categories served as a choice parameter to
insure a statistically valid distribution.
Flanges connecting end pieces to vessels and heat
exchangers are generally larger than typical in-line flanges.
A separate flange category was established for vessel/exchanger/
air-rcooler flanges. Within this category of special service
flanges, the choice variables were pressure/temperature cate-
gory and gas/liquid service.
Pump and Compressor Seals
Pumps and compressors contribute significantly to the
overall fugitive emissions problems because of leakage around
the shaft seals. Pumps and compressors in refinery service
utilize two basic types of seals, packed and mechanical. How-
ever, the designs of pump and compressor seals differ because
of the difference in the fluids they handle. Pumps and com-
pressors will be individually discussed below.
Pumps
Choice variables for pumps are listed below:
pressure/temperature,
size (capacity),
12
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shaft direction/seal type, and
Reid vapor pressure.
The four combinations of pressure and temperature
(P/T) were used as described previously. These operating con-
ditions affect many other areas such as seal type, method of
lubrication, and cooling methods. Several pumps can be found
for each P/T combination in almost every refinery.
Pump capacity is generally an indicator of shaft
size. The latter is the more important variable, but the
shaft sizes of every pump in a refinery may not be readily
available. Pump capacity better meets the three choice
criteria .-
significance,
availability,-and
usefulness.
Shaft direction/seal type is very significant as a
choice parameter. Information about pump types is both avail-
able and easily used. The L.A. County Study6 found that dif-
ferences in the relative numbers of seals in each category
(mechanical > packed/centrifugal > packed reciprocating) were
compensated for by the average leak rates (packed/reciprocating
> packed/centrifugal > mechanical) so that each category con-
tributed about equally to the total quantity of. hydrocarbon
emissions.
The final significant choice variable is fluid prop-
erties. Highly volatile hydrocarbons were found to contribute
70 percent of the fugitive pump emissions in L.A. County;5
13
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therefore, it was"decided to take fluid properties into account
in this study. The Reid Vapor Pressure (RVP) designations used
in that study were changed to < 1.5 Ibs RVP, 1.5- 10.5 Ibs RVP,
and > 10.5 Ibs RVP. This prevents gasoline and jet fuel from
being grouped into the same volatility category as the heavier
products.
Compressors
Choice parameters for compressor seals include pres-
sure, temperature, shaft motion, seal type, lubrication method
and capacity. The method of lubricating packed seals is an
important consideration. Packed seals without external liquid
lubrication will allow leakage of light hydrocarbons. Lubri-
cated seals will primarily leak heavy liquid hydrocarbons.
Mechanical seals us.ually require a lubricating/sealing fluid.
The types of shaft seals used in centrifugal compres-
sors could affect emissions because both types of packed seals
are used in similar service, as are both types of mechanical
seals.
Pressure-Relief Devices
Pressure, temperature, and fluid phase were selected
as choice parameters for pressure-relief devices. Temperature
and pressure of operation should affect the rate of emission
from pressure-relief devices. Higher pressures and tempera-
tures will provide greater driving forces for leakage. The
same four pressure/temperature categories described previously
were retained here with the exception of the LP/LT category.
14
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Pressure-relief valves are generally used in liquid
service; they open in proportion to the pressure applied to
them. Safety valves are used in gas service and pop fully open
when the set pressure is exceeded. Thus, the type of valve
operation is included in fluid state variables.
Process Unit Drains
Process drains are found in every operating unit in
a refinery. The nature of the emissions from the drains is
dependent on the hydrocarbons handled by the unit. Drains can
be classified as active and wash-up types. The nature of the
hydrocarbons handled by the unit, and the drain type, form the
principal choice criteria. Both active and wash-up drains can
be found in most refinery processes. There are more active
drains than wash-up, however. Therefore, sampling drains in a
representative number of the process units chosen for testing
allows both choice criteria to be met.
Site Specific Sampling Plan
Structured flexibility formed the tone of the sampling
plan. The structure assured that all needed measurement and
analysis requirements were efficiently covered. Flexibility
was maintained within a procedural framework to apply what was
learned toward subsequent sampling and analysis.
The sampling plan structure consisted of outlining
detailed procedures before sampling began. This included:
identification of process units to be
sampled,
15
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identification of number and type of
fittings within units,
specifying choice and correlating
variables, and
developing forms for recording screening,
sampling, variables, and analysis results.
>
Each site-specific sampling plan reflected modifications due
to what had been learned at previous refineries.
Baggable Source Selection - Field Selection
This section of the report contains a description of
the techniques, used in the field to preselect baggable fugitive
emissions sources.
The preselection methods given in this section were
used at the first nine refineries studied during the program.
The preselection methods used in the latter refineries are
given on page 24 of the report.
The primary goals of the preselection process were to
obtain:
a .statistically unbiased set of fittings,
selected in a random manner, and
a wide range of correlating parameters
or process conditions for each set of
selected fittings.
16
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The initial steps of the selection process were
carried out prior to the start of field sampling. These steps
included the selection of refineries and individual process
units to be sampled, and the development of a format for the
selection of individual sources.
The selection of individual baggable sources was done
using piping and instrumentation diagrams or porcess flow
diagrams supplied by the refiner. The approximate number of
sources selected at each refinery was -.
Valves 250 - 300
Flanges 100 - 750
Pumps 100 - 125
Compressors 10 - 20
Drains 20-40
Relief Devices 20 - 40
Selecting fittings from the process flow diagrams
gave two important benefits. First, this method eliminated any
bias which might have resulted had these fittings been selected
in the field. That is, fittings which could be determined to
be leaking by observation were not selected preferentially over
nonleaking fittings or vice versa. Second, a wide variation in
process conditions was desired. Using basic knowledge of the
process operation, it was possible to distribute the allotted
fittings such that a wide range in the values of variables
thought to affect the emissions rate was obtained.
The selection method used in the field is detailed
below for each type of baggable fitting.
17
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Valve Selection
The most difficult choice parameter to select was the
valve size. In most cases, a complete range of valve sizes was
not present in an individual process unit. However, since many
of the same process units were chosen in several refineries, an
exact distribution within each individual unit was not con-
sidered essential.
In general, all of the different hydrocarbon streams
within the process unit were incorporated into the valve selec-
tion process. When there was more than one valve for each
process stream (as was most always the case), valves were
selected to give a variety of temperature/pressure combi-
nations for each process stream.
The selection of valves within each process unit was
based on a format of the type illustrated in Figure A2-1. In
general, the number of valves allotted to each final grouping
was based roughly on the proportion of valves in the process
unit corresponding to that grouping. For example, a larger
fraction of the valves would be assigned to the gas/vapor
groups in a gas processing unit than in a lube oil processing
unit.
Pumps
Approximately 100 - 125 pumps were selected at each
refinery. These pumps were distributed in proportion to the
total number of pumps in each of the inspected process units.
The selection of individual pumps was based on obtaining a wide
distribution in process stream type, temperature, and pressure,
although the pump sizes and physical characteristics were also
18
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Selected
Process Unit
Organization of
Choice Variables
In Line Valves
^Gas/Vapor Service
Control Valves
^Size
< 4"
4-8"
> 8"
Block Valves
\<
Size
< 4"
4-8"
> 8"
Liquid Service
Control Valves
\«
"Size
< 4"
4-8"
> 8"
Block Valves
Size
< 4"
4-8"
> 8"
Typical Number of
Allotted Valves
Open Ended Valves-
Drain Valves
Sample Valves
1
2
1
2
4
2
3
3
3
7
7
7
1
JL
44
Figure A2-1. Typical Valve Selection Format
19
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considered. In addition, many spare pumps, (that is, pimps
that were not running) were also selected. These are usually
under pressure and were found to be sources of emissions.
Compressors
The number of compressors in hydrocarbon service in a
refinery is not large. Since compressors tend to leak at rela-
tively high rates, all compressors in hydrocarbon service were
selected. Compressors in hydrogen service were also selected
since recycle hydrogen and other impure hydrogen streams con-
tain hydrocarbons and other gases. Virtually all compressors
in the selected refineries were screened.
Pressure Relief Devices
Pressure relief devices were selected from process
flow diagrams and by visual selection in the field. Only those
devices which vented to the atmosphere were selected.
The choice parameters for pressure relief devices
included temperature, pressure, and fluid type, that is, gas
or liquid service. The number of liquid service relief devices
which vented to the atmosphere, however, was very low.
Flanges
Flanges were selected in a manner similar to valves
according to the format given in Figure A2-2. Again, a dis-
tribution in process stream type, temperature, and pressure
was obtained.
20
-------
Selected
Process Unit
Organization of
Choice Variables
Gas/Vapor Service
Size
< 6"
> 6"
Liquid Service
Size
< 6"
> 6"
Special Service . .
Orifice Flanges
Exchanger Flanges
Vessel Flanges
Typical Number of
Allotted Flanges
5
5
1
1
_1
18
Figure A2-2. Typical Flange Selection Format
21
-------
Many flanges listed in the data base were selected
in this manner. In some refineries, additional flanges were
selected to increase the size of the data base. These flanges
included primarily those associated with selected valves.
Drains
Two types of drains were inspected during the program.
These included active drains (those used to drain various pro-
cess streams) and washup drains. Although the location of
active drains was not usually indicated on the process flow
diagrams, they were still selected prior to entering the unit.
This was accomplished by selected drains associated with pumps,
towers, vessels, and other processing equipment. The location
of washup drains, however, could not be predicted and these
drains were visually and randomly selected after entering the
process unit.
Source Tagging
After the preselection process was completed, the
fittings chosen for study were located and tagged for identifi-
cation. Selections which proved to-be nonexistent or physi-
cally inaccessible were reselected from the process flow
diagrams. Each fitting was then screened with a portable
hydrocarbon detector, as discussed in the following section,
to determine if sampling was required.
Source Selection - Effect of Maintenance on Valves
At several refineries the effect on emissions of
simple valve maintenance was studied. Maintenance studies on
emissions from pump seals were planned, but none were done.
22
-------
Difficulties were" encountered in locating leaking pump seals in
the proper leak rate categories. In addition some pumps that
were found to be leaking could not be adequately isolated for
seal replacement. In some cases, there were no spare pumps
available to replace the leaking pump. In other cases, it was
felt that the time required and the cost incurred for seal
replacement was not justified by the size of the leak.
To evaluate control technologies for reducing fugi-
tive emissions from valves and to develop parameters for "off-
set" analyses using valve maintenance programs, data on the
effectiveness of various types of maintenance activities are
needed. In the last four sampled refineries, efforts were
directed toward this aspect of the program.
The maintenance on valves included:
simple adjustment/tightening of the
packing gland, and
injection of grease into the packing
area, if this is practiced by the
refinery.
Additionally, some valves were monitored for extended time
periods to determine:
the effectiveness of valve maintenanace
over an extended period of time,
the increase in emission rates for
unmaintained valves, and
23
-------
the frequency of routine maintenance
required to maintain selected emission
reductions.
The number of valves required to make the above eval-
uations can be limited through selective experimental design.
The wide variation in leak rates between valves can be circum-
vented by using paired measurement schemes for maintenance
evaluations. Only valves with particular selected leak rates
were studied.
The factors that were considered in selecting valves
for the maintenance study were:
Process stream group (gas/vapor
streams, light and two-phase streams,
and heavy liquid streams).
Valve type (block/gate, block/other,
control/globe, control/other).
Leak rate or screening value range
(500 - 5000 ppm screening value,
5001 - 50,000 ppm screening value,
and > 50,000 ppm screening value).
In addition, data were collected on all of the parameters
normally included in the program.
A total of 28 valves were proposed for study at each
refinery. The distribution of these valves is shown in Table
A2-2.
24
-------
TABLE A2-2.
DISTRIBUTION OF VALVES SELECTED FOR MAINTENANCE
STUDY IN EACH REFINERY
Valve Selection Categories2
Screening Values
by
Process Stream
Group
I Gas-Vapor
Streams
Valve
Type1
BG
BO
CG
CO
Low
(500-
5,000
ppm)
XO
0
X
0
Medium
(5001-
50,000
ppm)
XO D
X
X
X
High
(> 50,000
ppm)
XO
X
x n
X
Total
X's
10
II Light Liquid &
Gas-Liquid
Streams
BG
BO
CG
CO
XO
0
x D
0
XO
X
X
x a
XO
X
X
X
10
III
Kerosine
& Heavier
Streams
Total X's
BG
BO
CG
CO
X
0
x.
0
X
X
X
12
D
x
0
X
0
10
28
*Valve Type: BG * Gate valves in block (on/off) service.
BO » Types of valves, other than gate valves, in block service.
CG » Globe valves in control (throttling) service.
CO » Types of valves, other than globe valves, in control
service.
zValve Selection Criteria:
X
Valve should be maintained in this proces stream group
and screening value category.
0 - Alternate choice of valve process stream group and
screening value category if all "X" selections cannot
be found.
Q - Valve in this stream group and screening value category
should be selected for leak rate measurement, but no
valve maintenance is to be performed.
25
-------
The following procedure was used for determining the
effects and efficiencies of the maintenance practices on various
types of valves.
The required valves were found by
screening with portable hydrocarbon
detectors.
Complete variable information was
recorded for each selected valve.
Each valve was rescreened and sampled.
Routine type maintenance was performed
on the valve (tighten packing gland,
add grease, etc.).
The valve was then rescreened and
sampled.
Selected valves were rescreened for
several days.
The screening and sampling procedures are described
in following sections of the appendix. The maintenance that
was performed was defined as "directed" or "undirected."
Directed maintenance involves simultaneous maintenance and
screening of the source with a hydrocarbon detector. Mainte-
nance activities are continued until no further reduction in.
hydrocarbon concentration can be achieved. Undirected mainte-
nance consisted of the normal maintenance procedures without any
hydrocarbon concentration monitoring during the activity.
26
-------
Whenever possible, each maintained source was
rescreened several times during a period of one to two weeks
immediately following the maintenance. The purpose of this
activity was to get an indication of the short-term effective-
ness of directed and undirected maintenance.
Arrangements were made at some refineries to obtain
some data regarding the long-term effects of maintenance on the
reduction of emissions. In these cases, refinery personnel
agreed to monitor selected maintained valves at intervals of
one week to one month for a period of six months.
As part of the experimental study, quality control
procedures were implemented. These generally consisted of
replicate and multiple source screening, replicate source
sampling, accuracy testing of the sampling train, frequent
calibration checks, and frequent analysis of standard gases
in the laboratory.
2.1.2 Screening
In. order to minimize the number of sources which were
bagged, a preliminary screening was carried out to determine
the need for sampling. Those sources which were found to have
screening values above 200 ppm were selected for possible emis-
sions sampling. When it was determined that the leaks were
absent, sampling was not done. As the data base was expanded,
the screening value limit of 200 ppmv was found to correspond
to a leak rate in the order of 0.0001 pound per hour.
All the choice and correlating variables were
recorded, however, for all sources that were screened. The
27
-------
values were recorded on formatted data sheets. Examples of
these data sheets are shown in Figures A2-3 through A2-8.
New selection criteria were instituted during testing
activities at the fifth refinery. The data base was developed
to the point where leak rates of some sources could be estimated
from the screening values. Thus, some of the sources with low
screening values were not sampled. Instead, their leak rates
were estimated from their screening values.
There are several techniques that have historically
been used to screen potential sources in the baggable classi-
fication for leaks. These include visual observation of vapor
leaks, visual observation of liquid leaks or buildup of residue,
and spraying with soap solution. These methods are commonly
used in refineries as a means of identifying those equipment
items in need of maintenance, repair, or replacement. All
these methods are qualitative, however.
Many, if not the majority, of potential baggable
emission sources have skin temperatures above 100°C. Above
this temperature, the technique of spraying soap solution is
unusable, since it vaporizes on the hot source. Any bubbles
created by leaking vapors are indistinguishable from those
created by the vaporizing solution.
In Radian's experience in screening these sources,
significant leakage has been measured where none of the visual
methods indicated a leak. For this reason, a more accurate
indicator of leak rate was required to adequately identify
those selected sources that require bagging.
28
-------
1. Radian ID»| , V , A
1 2 3 4 5
3. Refinery ID*
2. Unit
VARIABLES:
4. Pressure, psig
5. Teoperature, *?'
6. Gas or liquid (G, L)
7. Line size, in
a 10 1112
13 14 19 1«
8. Block or control (B, C)
9. Valve t
ei -
n .
l«Ui n. flat 1 p
liaMi Ot -
-------
1. Radian ID* | , , , P
1 i 3 4 5 8 78
3. Refinery ID*
PI - Inboard
0 - Outboard
7ARIABLZS*
4. Discharge pressurt, psig ( , ,
11 12 13 14
S. Temperature, ? ' I i i j
18 18 17 18
6. Pump/seal type o - amu*,tu,m>*4
L» "WM «. -4 19 26
7; BJPM or strokes PM | ,
21 22 23 24 23
8. Stroke length (Recip, in) I
20 27 28 29
9. Capacity, GPM
_ 30* .31 32 33 34
10. Seal/lubefjlSr1 - 1 [ I
[l- kTttMOMI IflMlOMJ L
PROCESS FLUID DESCRIPTIOH:
18. Ran*
47 U'e-iV'so-sY 'isa-a'a 94 fr '58
SCSEENIHC DAIA:
19. Date of screening
57 SO W 80 81 82
21. Max TL7 . |
W^^"1^ 68 89 70
23. TLV daca
2. Unit
Note: Space 5 should be seal Idea
letter (A.3.C etc.). Use sa
sanpllsg sheet.
1 1 In-Servlce/Out of Service (I
11. Gland type t - «u\-«»
12. Single or double (S , 0)
13. Shaft diameter, in
14. Age, yrs
15. Manufacturer
16. Mtls of conatr
17. Horizontal or vertical (H, V)
20. Screening team 1
83 84
22. Liquid leak? (Y, N) 1 1
71
tlflcatlo
me ID on
/*)
L']
3d
LI
sr
38 39
40 41
42 43
I 1
44 49
P
/
Remarks:
Figure A2-4. Data Sheet - Pump Seal
30
-------
1. Radian ID* . , , C 0 _ _
3. Refinery ID
VARIABLES :
4. Discharge pressure, paiz . __
9 10 11 12
S. Temperature, ? , ,
r »*»- 13 f1* '* '8
6. Cotsp/seal typeL^, * _U
-------
1. Badiaa ID* [ _ R _ V ,
1 23* 98 73
3. Refinery ID*
2. Bnic
VARIABLES:
4. Pressure, psig
S. Temperature, *7
6. G*s or liquid (G. L)
7. Line size, la
3. Single or double (S, 0)
9
*'
13 10
P
P
PROCESS DESCBX7TIOH:
10. ttaau
22 23 24 29 20 27 28 29 30 31
SCREENING DATA (Oaly for acaospheric-venced valves):
11. Dace of screening
12. Screening team
32 33 34 35 38 37
38 38
13. TLV readings
14. Max TLV
40 41 42 43 44 45
IS. Liquid leak? (T, N)
P
Remarks:
Figure A2-6. Data Sheet - Relief Valve
32
-------
1. Radian ID*
2. Unit
12345973
3. Befinery ID*
VARIABU
4. Press
5. Temp*
6. Ga« c
' 7. Line
PROCESS
15. Name
3:
lure, psig
9 10 11 12
sracure, *?
13 14 iTTa1
>r liquid (G, L) | {
size, ia f t \
ri . _u ~i "ia is
n - rut [« ,
a . m ft. I ' 1
fB (10MUM tMttrf
r T M«M»
... . , , U - U* ea«Ur ]
9. Special service o - gnuc* >u«
ll ^Mi/ua J 2z
10. Age, yrs
23 24
11. Mts. of const. [ JJ " '""M
25 28
12. Manufacturer f -I
27 28 '
13. Gasket mcl
B « 1 29 ^-i
14. Vibration!* - "»« 1
X - ««."«
L«-» T J TT^
FLUID DESCRIPTION:
32 33 34 35 3« 37 38 39 40 41
SCSEEHINC DATA:
16. Dace
of screening
17. Screening team j /
42 4» 44 49 48 47
«a 40
18, Liquid leak (Y, N)
D
so
19. TLV readings
20. Max TLV
Remarks:
51 92 S3
3»
Figure A2-7. Data Sheet - Flange or Weld
33
-------
L. JUdian ID*
D R
123*59 73
2. unit
3. aarinerr
P
n
10
7ABTAHT gg;
4. Active or wash-up? (A, H)
S. 7ia±bla vapor emission? (?, S)
6. Temperature of input, *?
7. Sactangular or circular opening? (R, C) [ |
3. Olanwcar if circular (in.)
9. Langth if rectangular (in.)
10. Width if rectangular (in.)
11 12 1C 1*
TT
18 17 18 19
20 21 22 23
24 23 28 27
DESCRIPTION OF INPUT TO DRAIN;
11. Same
28 29 3O 31 32 33 3* 35 30 37
SC3EHTCIG DA1A:
12. Data of screening
13. Scraaning caam
14. Max TL7
38 39 *O 41 42 43
13. TL7 readings
46 47 43 49 30 51
Remarks:
Figure A2-8. Data Sheet - Unit Drain
34
-------
Instrumentation
A Bacharach Instrument Company J-W Model TLV Sniffer
has been found to be useful for the screening of baggable
sources. This instrument utilizes a catalytic combustion
detector to measure low concentrations of flammable vapors.
It can detect hydrocarbon concentrations as low as 1.0 ppm.
Three concentration scales, 0 - 100 ppm, 0 - 1,000 ppm, and
0-10,000 ppm, are built into this instrument. A dilution
probe was used when the TLV readings exceeded 10,000 ppm which
allowed readings of up to 100,000 ppm. The instrument meter
displays the result as ppm hexane by volume when calibrated
with hexane. It is battery operated, self-contained, compact
and portable. The instrument performance has been very
satisfactory.
A second instrument used to screen for hydrocarbon
emissions was the Century Instrument Company Organic Vapor
Analyzer (Model OVA-108). This instrument utilized a flame
ionization detector to measure hydrocarbon concentrations. The
role of the OVA was limited to obtaining original screening
values only. When leaking sources were identified, they were
rescreened with the TLV Sniffer when the source was sampled.
Recommended Calibration Procedure for the TLV Sniffer
Each of the concentration ranges on the TLV Sniffer
must be calibrated separately. This requires different hexane-
air standards. The recommended concentrations for each of
these standards are given below:
35
-------
TABLE A2-3. TLV CALIBRATION STANDARDS
Concentration Range on TLV
Recommended Calibration
Standard Concentration;
ppmv hexane in air
0 - 100 ppmv range (x 1)
0 - 1,000 ppmv range (x 10)
0 - 10,000 ppmv range (x 100)
None
200-900 ppmv hexane
2,000-5,000 ppmv hexane
It was not felt necessary to calibrate this low range since 200 ppm was
the cut-off point for sampling.
Teflon or Tedlar sample bags were used during the
calibration procedure. Each bag was labeled with the concen-
tration of the assigned standard gas. The bags were not filled
with any gas, other than the assigned standard.
The step-by-step procedure for calibrating the TLV
is given below. The calibration was done at the beginning of
each day the TLV was used.
(1) Clean the sample probe and hose with
methylene chloride. Dirt or other
accumulation in these areas can have
a pronounced effect on the concentra-
tion reading, particularly in the
dilution probe mode. Residual methylene
chloride can be removed more quickly by
blowing air through the probe and hose.
(2) Turn on the TLV and check the battery
charge level. Allow 10 minutes warm-up
time before starting the calibration.
36
-------
(3) Remove Che plastic casing from Che TLV
and locate- Che chree small adjustment
screws. These are labeled xl, xlO, and
xlOO, corresponding Co the concencration
ranges indicated on the mode selector
switch.
(4) Place the instrument in an upright posi-
tion. Changing the position of the
instrument will affect the distribution
of heat in the catalytic element and
change the meter reading.
Each of the concentration scales must be calibrated indepen-
dently. Hence, the following steps (5 through 9) should be
performed for one of the concentration scales and then repeated
for each of the others. Also, make sure that the dilution air
intake holes in'the dilution probe are completely covered by
the black rubber ring during the entire calibration procedure.
(5) Flush the calibration bag by filling it
with, the appropriate gas standard. Then,
compress the bag to remove as much gas
as possible. Repeat this procedure cwice.
(6) Fill Che sample bag wich calibration gas.
(7) Attach a small length of rubber tubing to
one of the valves on the bag. Manually
pinch off the tubing and open the valve .by
spinning Che bag. Place Che end of che
rubber Cubing over Che TLV probe and allow
the standard gas to enter the TLV for about
37
-------
10" seconds. Pinch off the rubber
tubing and remove the rubber tube
from the probe.
(8) While keeping the tube clamped, wait
till the meter reading has stabilized.
Zero the meter on the appropriate
scale using the fine and/or coarse
adjustment controls.
(9) After zeroing the meter, allow more
standard gas to enter the TLV. The
bag should hang freely from the end
of the probe, i.e., no external pres-
sure should be applied on the bag. Turn
the. appropriate adjustment screw until
the meter reading corresponds to the
concentration of the standard gas. If
a substantial adjustment is required,
it will be necessary to rezero the meter
and repeat the calibration (steps 8 and
9).
The probe can also function as a dilution probe.
This extends the range of the TLV from 10,000 ppm to 100,000
ppm. To operate the dilution probe, the black rubber washer
is pulled back to expose the dilution air intake holes. In
this mode, the meter will read a concentration which is
approximately one-tenth of the actual concentration.
This dilution factor can be verified by reading the
high-range (xlOO) gas standard with the meter zeroed, on the
38
-------
mid-range (xlO) scale. The dilution factor is calculated as
follows:
Dilution factor - PP^r calibration »aa s 1Q
ppmv, meter reading
All subsequent screening results are multiplied by the dilution
factor obtained here.
Preparation for Screening
The following equipment was included in the field
screening gear:
Recording equipment, notebook, data
sheets, pens, etc.
TLV Sniffer, hose, and dilution probe.
Extra cotton filters, pipe cleaners,
and paper towels.
Knapsack or similar for carrying equip-
ment to elevated sources.
In order to insure that all screening results are
obtained on an equivalent basis, the following procedures
are recommended.
The battery pack should be fully
recharged before the start of screen-
ing. Generally, an overnight charge is
sufficient to provide eight hours of
continuous screening time.
39
-------
The TLV Sniffer and the dilution probe
should be calibrated before the start
of each sampling day.
Ten minutes warm-up should be allowed
before screening.
The meter (xl scale) should be zeroed
before screening each source. The meter
can be zeroed in any open area since
ambient hydrocarbon readings are usually
quite low.
The small orifice in the dilution probe
should be free of dirt or other accumu-
lation. When a source is encountered
which requires the use of the probe in
the dilution mode, the dilution orifice
should be inspected. In addition, the
small diameter extension and the cotton
filter chamber sections of the probe
should be inspected and cleaned frequently,
If. the cotton filter gets wet, it should
be replaced.
Screening should always be done with the
meter in an upright position, as the meter
position affects the distribution of heat
in the catalytic element.
40
-------
Common Operating Problems
There are several situations which may arise that
could cause difficulties in obtaining proper results. Some of
the more common problems are discussed below.
On some TLV Sniffers, the zeros for each of the three
concentration ranges may not coincide. If this is the case the
magnitude of the difference should be determined and screening
values adjusted accordingly. For example, assume that the
meter has been zeroed on the (xl) scale and a reading of 500
ppm is obtained when the meter is switched to the (xlOO) scale.
In this case, 500 should be subtracted from all readings taken
on the (xlOO) scale. Small differences from one scale to the
next, however, may be neglected.
In some cases, it may be difficult to determine
whether a meter response is due to high ambient air hydrocar-
bons or a source leak, particularly when the ambient reading
is highly variable. This problem is commonly experienced in
compressor houses or other enclosed areas. One method to
determine if the source is leaking is to place the probe at
the leak source and then remove it from the leak source. This
operation is repeated at regular intervals. If the movement
of the needle corresponds to the placement and removal of the
probe (keeping in mind the two-second time lag), the source is
probably leaking. The screening value is then determined by
subtracting the ambient reading from the measured screening
result. A variety of such situations may be encountered and a
judgment on the part of the operator may be required to obtain
a representative reading.
41
-------
Occasionally, a source may be encountered which has a
highly variable leak rate! The design of the TLV Sniffer tends
to damp these variations somewhat; however, some oscillation in
the reading may still occur. In general, the maximum sustained
reading or the maximum repeatable reading should be recorded.
Again, a judgment on the part of the operator may be required
to obtain a representative reading.
One further screening difficulty may arise when
screening sources which contain heavier hydrocarbon streams,
particularly on hot sources. When these valves are screened
some of the vapor tends to condense on the internal probe-
sample hose surfaces. The response of the meter is considerably
slower for these sources relative to that seen when screening
lighter hydrocarbons. And, the meter may require more time to
return to zero. When screening this type of source, the meter
should be allowed to stabilize before recording the result.
The meter should be allowed to return to about 20 percent of
the recorded value before moving to the next screening point.
Prior to screening the next source, sufficient time should be
allowed for the meter to stabilize or return to zero. Often
the meter will not return completely to zero and a considerable
adjustment may be required.
Under no circumstances should the end of the probe
be placed in contact with liquid. If liquid is drawn through
the sample hose, it will damage the catalytic element. A
liquid trap, connected between the TLV Sniffer and the sample
hose, was used. This gave some protection against damage to
the element.
42
-------
Screening Procedures
The procedure used for screening with the TLV Sniffer
was quite simple. The sample probe was held as close as possi-
ble to the suspected leak source. This reduced the effect of
the wind and increased the reproducibility of the readings.
The screening procedure differed slightly for each baggable
source type as discussed below.
Valves Screening Methods
Most of the valves that were selected for screening
were either gate, globe, or control valves. Hydrocarbon leaks
from these valves occur at the stem and/or the packing gland,
as indicated in Figure A2-9. Some plug valves were also
selected. Hydrocarbon leaks from this type of valve can occur
at the plug square or under the malleable gland, as indicated
in Figure A2-10.
Both the stem and the packing gland of selected valves
were screened. The probe locations used included the four
arbitrary compass points around the seal, relative to the valve
casing. Thus, a total of eight such readings were taken for
each valve. In addition, two more readings (one for the stem
and one for the glands) were obtained at a distance of 5 cm
(using a wire extension as a guide) from the leak source. The
probe was rotated in a circular path around the leak source and
the maximum reading was recorded.
Flanges
Flanges were screened by placing the TLV Sniffer
probe at two-inch intervals around the perimeter of the flange.
43
-------
Gate, globe, and
control valves are
screened at these
two locations. Four
readings are taken at
each location.
Figure A2-9. Gate Valves
44
-------
Plug valves are screened at
these two locations. Four
readings are taken at each
location.
Plug
n n
Body
Figure A2-10, Plug Valves
45
-------
After locating the maximum leak point, three additional
readings were taken at the remaining compass points, relative
to the location of the maximum leak point. All four readings
were recorded.
Pump and Compressor Seals
Pump seals were screened in a manner similar to that
used for screening valves. Leakage occurs around the rotating
shaft at the point where it enters the pump housing. The
Bacharach TLV Sniffer probe was placed as close as possible to
the potential leak point around the shaft at the pump housing.
Prior to this, the instrument was zeroed at ambient conditions.
Four readings were taken at points 90 degrees apart around the
shaft. Also, the maximum readings, taken at a distance of
5 cm, were recorded. The probe was left at each point for a
minimum of 5 seconds. The detection of hydrocarbon at a con-
centration of 200 ppm at any of the four points resulted in the
pump being bagged and sampled.
Large pumps or pumps in severe services may have two
seals, an inboard seal and an outboard seal. In these cases,
each seal was screened separately.
The screening procedure for compressors depended on
the accessibility of the seal area. If the seal area was
accessible, the screening procedure was identical to that for
pumps. After zeroing at ambient conditions, the TLV Sniffer
probe was placed at four locations 90 degrees apart around the
shaft and. right at the point where the shaft enters the com-
pressor housing. A hydrocarbon concentration of 200 ppm or
more at any point indicated the need for bagging and sampling
of the seal.
46
-------
In many" cases the seal area was enclosed and
hydrocarbons leaking from the seal were vented to the atmo-
sphere or to a vapor recovery system. When compressors vented
to the atmosphere were encountered, they were screened and
sampled, if necessary, at the point where the vent pipe dis-
charged to the air. The TLV probe was positioned at a point
located just inside the end of the vent.
Compressors often have more than one seal. Each seal
was individually screened and, if necessary, bagged and sampled.
Pressure-Relief Devices
Only those pressure-relief devices that are vented to
the atmosphere were screened. Those devices that are vented to
blowdown and flare systems can only leak to the atmosphere at
the connecting flanges, and these leak sources are considered
to be flanges.
The relief valves were screened using the Bacharach
TLV Sniffer. After zeroing the instrument at ambient condi-
tions, the probe was placed at two-inch intervals around the
perimeter of the vent '(horn) just at the exit. The probe was
also placed at the center of the vent opening at a level with
the vent exit.
When the top of the horn was inaccessible, a screen-
ing value was obtained at the weep hole, located near the
bottom of the horn. The probe was left at each location for
a minimum of five seconds. If a hydrocarbon concentration of
20 ppm was detected during this five-second period, the probe
was left in place for at least an additional five seconds. The
maximum TLV readings during the ten-second period were recorded.
47
-------
If any readings exceeded 200 ppm, che relief device was to be
sampled and bagged.
Drains
In this program, process unit drains were classified
as either active or washup drains. The screening process is
the same for both types.
The Bacharach TLV Sniffer was zeroed at ambient con-
ditions. Then the probe was placed at two-inch intervals
around the perimeter of the drain. At each of these points,
the probe was placed right at the inside edge of the drain at
the level of the exit. The probe was left in place for at
least five seconds. If, during this time period, a hydrocarbon
concentration in excess of 20 ppm is detected, the probe was
left in place for an additional five seconds. The maximum con-
centration detected in this ten-second period was recorded.
Upon completing the traverse around the perimeter of
the drain, one additional reading was taken at the center of
the drain. The maximum of the perimeter and center readings
was recorded and used as the basis for sampling decisions. If
the maximum individual value was equal to 200 ppm hydrocarbon
or greater the drain was bagged and sampled.
2.1.3 Sampling Train
The method preferred for sampling leaks from baggable
sources is the dilution or flow-through method. The sampling
trains that were used in this method are shown in Figures A2-11
and A2-12. The train was contained on a portable cart, which
could be easily pushed around the unit from source to source.
48
-------
vO
f=S
FENT
c^
O
nr
i
x
WATER
MANOMETER
THIS LINE SHOULD
=. OE A3 SHORT
yAS POSSIBLE
W J
^m ' ^ 1
nf 1 x v
aJ LU COLO TRAP t =a/ \
hllQEBATIII /^_J
\^S THREE* Jl SAMPLE
LEAKING WAY f OAQ 0
VALVE VALVE 1
TRAP
Tf~
(?) Hg MANOMETER
ir ~i vy
,a ifca ^^
»-i CONTROL
*~^ ^ VALVE t
m
JKi'M,8 El
TLV
SNIFFER
FILTER VACUUM PUMP
SYRINGE
Figure A2-11. Sampling Train for Baggable Sources of Hydrocarbon
Emissions: Flow-Through Method Using a Syringe
-------
MAGNEHELIC
Ul
o
TENT
til
LEAKING
VALVE
THIS LINE SHOULD
BE A3 SHORT
AS POSSIBLE
COLO TRAP
(ICE BATH)
TRAP
DRY GAS
METER
Hg MANOMETER
CONTROL
T VALVE
x«
FILTER VACUUM PUMP
SAMPLE BAG
SMALL s
DIAPHRAGM \
PUMP TWO WAY VALVE
Figure A2-12. Sampling Train for Baggable Source of Hydrocarbon
Emissions Using a Diaphragm Sampling Pump
-------
The major equipment items in the sampling train were
the vacuum pump used to draw air through the system, and the
dry gas meter used to measure the flow rate of gas through the
train.
The vacuum pump as a 4.8 CFM Teflon-ring piston-type
equipped with a 3/4 horsepower air-driven motor. Low pressure
air (~ 100 psig) is available at or near most refinery process
units.
The dry gas meter was a Rockwell Model 1755 Test Gas
Meter with a Number 83 Test Index.
Other equipment in the trains includes Whitey valves,
copper and stainless steel tubing, Teflon hose, 100 cc glass
airtight syringe, thermometers, mercury and water manometers, a
cold trap, and an air-driven diaphragm sampling pump.
The leak source is shown as a valve in the figures.
However, the same sampling train was used for all baggable
source sampling with the flow-through technique. The size and
shape of the leak source enclosure (tent) was changed and
adjusted to fit each particular source shape and operating
condition.
When the sampling train is operating, the vacuum pump
is able to maintain a maximum flow rate of approximately two
and one-half cubic feet per minute.
Sample bags were used to collect gas samples and
transport them to the mobile laboratory for analyses. Several
types of bags were tested by Radian in the laboratory and in
the field. Most of them, including Calibrated Instrument
51
-------
Company's five-layer "snout" bags, were found to adsorb
hydrocarbons, making them unsuitable for use. Bags of 2 mil
Mylar and Tedlar plastic were constructed, and were found to
be very satisfactory. A drawing of a typical sample bag is
shown in Figure A2-13.
A cold trap was placed in the system to condense
water and heavy hydrocarbons, thus preventing condensation in
downstream lines and equipment. The cold trap was simply a
500 ml flask in an ice bath and was placed as close as possible
to the tent. This ice bath was found to be very effective in
preventing condensation in the remainder of the sampling train
and in the gas sample bag. Any organic condensate that
collected in the cold trap was measured and recorded for later
use in calculating total leak rates. The use of such a cold
trap is critical; without it, order of magnitude errors are
possible and, in some cases, probable.
2.1.4 Tent Construction
An enclosure or tent of Mylar plastic (polyethylene
terephthalate) is formed around the leak source. The thickness
of the Mylar can range from 1.5-15 mil depending on the type
of source being bagged. Radian has found that Mylar is well
suited to this function as it does not absorb significant
amounts of hydrocarbons, it is very tough, and it has a high
melting point (250°C). A typical tent is shown in Figure A2-14.
The enclosures were kept as small as practical. This
had several beneficial effects:
The time required to reach equilibrium
was kept to a minimum.
52
-------
Figure A2-13. Mylar Plastic Sample Bag
53
-------
Mylar Bagging
Flexible Plastic
Mesh Reinforcing
Material Beneath
Surgical Tubing
Pressure Tap
Outlet to
Pump
Figure A2-14. Tent Construction Around the Seal Area of
a Vertical Pump
54
-------
The time required to construct the
enclosure was minimized.
A more effective seal resulted from
the reduced seal area.
Condensation of heavy hydrocarbons
inside the enclosure was minimized or
prevented due to reduced residence
time and decreased surface area avail-
able for heat transfer.
In a typical sampling operation, the tent was con-
structed around the leak source and connected by means of the
bulkhead fitting and Teflon hose to the sample train.
A separate line was connected from the tent to a
magnahelic. This allowed continuous monitoring of the pressure
inside of the tent. If a significant vacuum existed inside the
tent when air was being pulled through, a hole was made in the
opposite side of the tent from the outlet to the sampling train.
This allowed air to enter the tent more easily and thus
reduced the vacuum in the enclosure. In practice, it was found
that only a very slight vacuum (0.1 in. H20) was present in the
tent during most of the sampling, even in the absence of a hole
through the tent wall. Sufficient air enters around the seals
to prevent the development of a significant vacuum in the tent.
Tent construction for individual sources is discussed
below:
55
-------
Valves -
One of the most numerous of the baggable sources to
be examined in refineries was valves. Radian generally found
them to be a relatively easy source to sample.
All valves were sampled in the same general manner.
The principle difference was that a greater degree of care was
taken in sampling control valves so that there was no possi-
bility of interfering with the control valve mechanism or
operation during the sampling interval. This was not as
critical when sampling block valves, because these normally
remained in a fixed position during the sampling effort.
The most important property of the valve affecting
the type of enclosure (tent) selected for use is the metal skin
temperature existing in the area enclosed by the tent and
around which the seal is made.
At skin temperatures of 400°F or less, the valve stem
and/or stem support was wrapped with 1.5-2.0 mil Mylar plastic
and sealed at each end and at the seam with duct tape. A leak-
tight seal is not required when the flow-through method of leak
measurement is used. Indeed, it is better to allow for some
areas of incomplete sealing to provide access for air being
drawn through the tent by the vacuum pump in the sampling train.
Two bulkhead fittings are attached to the Mylar tent.
One is for the water manometer or differential pressure gauge
connection, and the other is for the line to the sampling train.
If, after starting the sampling, a vacuum > 0.5 inch of water
was found to exist in the tent, a hole was added on the side of
the tent opposite the outlet to the sampling train. This
56
-------
provided an additional entrance for the dilution air, and the
vacuum in the tent was reduced while sampling.
The Mylar tent was constructed to enclose the valve
stem seal and the packing gland seal. The bonnet flange was
not enclosed since this source was considered as a flange.
When skin temperatures in excess of 400°F were
detected on a valve which was sampled, alternate methods of
tenting the valves were used. In one method, asbestos insula-
ting tape was wrapped around all hot points which were in con-
tact, with the Mylar tent material. Seals were then made
against the insulation using duct tape or adjustable metal
bands ,pf stainless steel.
At extremely high temperatures, metal foil was
wrapped around the valve leak area. Seals were made using
adjustable metal bands inmost cases. Occasionally, at
points where the shape of the equipment prevented a satis-
factory seal with metal bands, the foil was crimped against
the seal sites to make a seal. It was necessary, in some of
these instances, to use a relatively high capacity vacuum
pump to insure a constant inflow of air through all seal areas
Mixed-phase valve leaks were handled with the same
type of enclosures described above. The leaking liquid was
collected at a purposely-formed low point in the tent. This
liquid rate was measured over the sampling period.
Pumps
As with valves, the property of most concern when
preparing to sample a pump was the metal skin temperature
57
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at areas or points that were in contact with the tent
material.
At skin temperatures below 400°F, Mylar plastic and
duct tape are satisfactory materials for use in constructing
a tent around a leaking pump seal. The vast majority of
centrifugal pumps in refineries have a housing or support that
connects the pump drive (or bearing housing) to the pump itself.
The two supports normally enclose about half of the area
between the pump and drive motor, leaving open areas on the
sides. It is usually a relatively simple matter to cut panels
to fit these remaining open areas. The panels were cut from
14 mil Mylar. Bulkhead fittings for the outlets to the water
manometer and sampling train were placed through one Mylar
panel and sealed. An opening (hole, bulkhead fitting) was
made in the opposing panel, if necessary, to allow easier flow
of dilution air into the enclosure around the seal.
In many horizontal pumps, there is a line from the
bottom of the lower metal support to a drain. This line serves
as a drain for coolant, sealant, and/or process liquid leaking
from the pump seal. This line (and all other lines from the
enclosure) was sealed off to avoid drawing air arid hydro-
carbon vapors from the drain back up to the sealed enclosures.
If there is no liquid flowing through this drain line, it was
plugged, off. If liquid was going to the drain, a short length
of hose or tubing was attached to the end of the drain line
and looped upward to form an effective liquid seal.
In the cases where the supports were absent or quite
narrow, a cylindrical enclosure around the seal was made such
that it extended from the pump housing to the motor or support
58
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bearing. This enclosure was made completely of 14 mil Mylar,
since this thickness provided considerable strength and
rigidity.
Reciprocating pumps presented a somewhat more diffi-
cult tenting problem. If supports are present, the same type
of^wo-panel Mylar tent can be constructed as that for centri-
fugal pumps. In many instances, however, sufficiently large
supports are not provided, or the distance between pump and
driver is relatively long. In these cases, a cylindrical
enclosure similar to that used for centrifugal pumps was con-
structed. It was impractical to extend this enclosure all the
way from the pump seal to the pump driver. In this case, a
seal was made around the reciprocating shaft. This can
usually be best effected by using heavy aluminum foil and
crimping it to fit closely around the shaft. The foil was
attached to the Mylar plastic of the enclosure and sealed with
duct tape.
If the temperatures was too high or the potential
points of contact too numerous to insulate, an enclo.sure
made of aluminum foil was constructed. This enclosure was
sealed around the pump and bearing housing using asbestos
insulating tape.
In cases where liquid and vapors were leaking from a
pump, the enclosures described above were used. The outlet
from the tent to the sampling train was placed at the top of
the enclosure and as far away from the spraying leak as
practical. Thus, entrainment of the liquid into the sampling
train (and cold trap) was avoided. The rate of leakage of
liquid was measured by collecting it over a measured length of
59
-------
time. A low point was formed in the tent, and liquid was
collected at that point, and its volume measured.
Compressors
In general, the same types of tents that are suitable
for pumps can be directly applied to compressors. The con-
struction and application of these enclosures have been
described in the preceeding discussions of pump sampling and
will not be repeated in this section.
Compressors generally handle light gases, and in many
cases, the seals are enclosed. The seal enclosures are vented
to the atmosphere at a high-point vent or may be vented to the
blowdown/flare system.
If the seals are vented to a high-point vent, this
vent line was sampled. A Mylar bag was constructed and sealed
around the outlet of the vent and connected to the sampling
train. The leak rate from the vented compressor seals was
then measured using the normal flow-through method.
In the event that high-point vents were inaccessible,
the vent lines from the compressor seal enclosures were dis-
connected at some convenient point between the compressor and
the normal vent exit. Sampling was then done at this inter-
mediate point.
When enclosed compressor seals were vented by means
of induced draft blowers or fans, the outlet from the blower/
fan was sampled. A pitot tube was used to determine the air
flow rate. A sample of the outlet air was taken and returned
to the mobile laboratory for methane and nonmethane hydrocarbon
60
-------
analysis. Ambient air samples were taken around the compressor
seal enclosure area at the same time and were analyzed for
hydrocarbon content. The compressor seal leak rate was deter-
mined from the knowledge of air flow rate, its hydrocarbon
content, and the hydrocarbon content of the ambient air.
Flanges
All types of flanges, ranging from small-piping and
valve-bonnet flanges to very large exchanger and vessel flanges,
were sampled. In most cases, the physical configuration of
flanges lends itself well to the determination of leak rates.
For small to moderately large leaks on flanges with metal skin
temperatures up to about 400°F, a narrow section of Mylar film
was used to span the open distance between the two flange faces
of the leaking source. The Mylar was attached and sealed to
each flange with duct tape. Connections (bulkhead fittings)
for the water manometer and sample train were attached to the
Mylar.
When testing flanges with skin temperatures above
400°F, Mylar film and duct tape were not normally used. Instead,
the outside perimeter of both sides of the flange connection
was wrapped with asbestos insulating tape. Then a narrow strip
of aluminum foil was used to span the opening between the
flange faces. This narrow strip of material was sealed against
the asbestos tape using adjustable bands of stainless steel.
Relief Valves
Relief devices in gas/vapor service generally relieve
to the atmosphere through a large diameter pipe, often called
a "horn," which is normally located at a high point on the unit
61
-------
that it serves. The horns can be easily bagged by placing a
Mylar plastic bag over the opening and sealing it to the horn
with duct tape. Because of the height above grade of many of
these devices, accessibility to the sampling train was limited
or prevented. It was sometimes possible to run a long hose
from the outlet connection on the bag to the sampling train
located at grade level.
Process drains have been classified as "active" or
"washup" drains. The procedure for sampling is the same for
both types.
Mylar plastic was used to tent the open top of the
drain. This was cut to fit around any of the various pipes
that may extend down into the drain. The mylar was sealed
around these protuberances with duct tape. The seal around
the drain edge was made with duct tape or aluminum foil. This
seal was relatively loose to allow air to flow in around the
edge of the drain and out through the tent connection to the
sampling train.
Another connection on the drain tent was connected
to a very sensitive differential pressure guage (Magnehelic).
When the sampling train was operating, the vacuum inside the
drain tent was monitored. The vacuum was kept to a minimum to
avoid vaporizing, and thus sampling, more material from the
drain than would ordinarily be present when the drain is open
to the atmosphere.
2.1.5 Sampling
The cold trap was connected to the tent and immersed
in an ice bath. Then the vacuum pump was started and the
62
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timing of the run-was simultaneously initiated. The time,
pressure and temperature at the dry gas meter, and the dry gas
meter reading, were recorded. These data were recorded at 2-10
minute intervals. Equilibrium was normally reached within five
minutes or less. Sampling was not started until equilibrium
had been established throughout the system.
The TLV Sniffer was placed in the sample train at the
exit of the vacuum pump. The instrument was used to monitor
the gas stream in order to assure that equilibrium had been
established.
To sample the gas stream, an evacuated Mylar sample
bag, which had been previously completely flushed with air for
an extended period at the mobile laboratory, was attached to a
three-way valve in the sampling line. A 500-ml air-tight gas
syringe was used to withdraw gas samples from the sampling
train. The syringe and bag were first completely flushed with
sample gas. Then a sample was drawn very slowly (to avoid
altering the flow rate through the tent) from the system and
transferred to the bag by means of the three-way valve. This
operation was repeated until the sample bag was full (5-7
liters). Alternately, air samples were taken using a small
air-driven vacuum pump.
At the same time that this sample was being withdrawn,
an ambient air sample was taken near the tent. This air sample
was taken with a large plastic syringe and transferred to a
Mylar sample bag. The gas sample, data sheet (Figure A2-15)
and ambient air sample were taken to the mobile laboratory
for analysis. The vacuum pump was then stopped and a final set
of readings recorded. The cold- trap was removed from the ice
bath, sealed, and sent to the laboratory for analysis. The tent
63
-------
1. Badlaa
2. Type of sample
4. Sampling team
7. H.3.»
U. B*r. praaa. , la. Sg
13. DGM correction factor
13. Total vol.
condesuate, ml
17. Coll. time, ola
27 28
29 30 31
i i i
32 33 34 38 38
14. Mater #
37 34 39 *0 *1
42 *3 44 49 46
16. Vol. org.
condensace, ml
47 48 49 30 5!
52 5354 S3
18. Specific gravity of
organic condaasaca
SO 37 58
AMALYSIS DATA; ALTEPIAIE ANALYSIS METHOD:
ttethane tfonmthane Methane Sonmethane
Ambient air (1) (1) (1) (1)
(2) (2) (2) (2)
19. Avg.
Sample
21. Avg.
20.
38 90 91 92 93 94 99 88 87 83
(1) (1)
(2) (2)_
A I . t .
9990 61 82 93
20.
99 70 71 72 73
22.
t 1 1 1 (
(2)
94 99 98 97 88
(1)
(2)
74 73 79 77 78 79
21. Avg.
22.
99 r6 71 7J 73 74 7S T9 77 79 TV
CALCULATED LEAK, SATES (Ib/hr):
Methane
^onmethane
Total
7apor
Condensaca
RESOtEEHISC DATA:
Radian ID*
Screening Team
1 2 3. 4 9 3 7 3
Screening Concentration, ppa
Reacreeoing
Date
9 10 11 12 13 '4
Screening
T.
19 18
All soiircea,
7alve St«m ' .'.. ' ',, L. '
17 18 19 20 21 22 23 24 29 28 27 28 29 30 31 32 33 34 39 38 37 38 39 40
vaive racking
Gl^nd
i i i i
1 i 1 i 1
i i i i i
4» 42 43 44 49 4« 47 48 49 SO 91 92 9334 59 38 37 38 39 90 81 92 93 94
VWw*
f CM Value
67
10
TI Tl. T? T4 rt
ISJ
80
Figure A2-15. Data Sheet - Baggables and Tented
Liquid Leaks
-------
was then removed "from the source, and the train moved to the
next sampling point.
Baggable Sources - Procedure for Large Vapor Leaks
Radian refinery sampling experience has shown that
large vapor leaks are occasionally encountered. These leaks
are so large that very high concentrations of hydrocarbon are
found in the gas samples. Since the Byron THC Analyzer cannot
measure concentrations above 20,000 ppm, considerable dilution
of the sample was required in order to obtain a diluted gas
concentration in the proper range.
In some cases, a leak may be large enough to exceed
the capacity of the vacuum pump. This leads to a pressure
buildup in the tent and sampling train. Ultimately, leakage
around seals or rupture of the tent occurs. In any event,
erroneous results are obtained.
When large leaks are encountered, direct measurement
of the hydrocarbon vapor rate is the quickest and most reliable
method of determining the leak rate. In these cases, the
vacuum pump is disconnected from the sampling train. The gas
from the leak source is allowed to pass through the sampling
train (including the cold trap) and exit to the atmosphere
Immediately downstream of the dry meter. After equilibrium has
been established, the flow rate through the dry gas meter is a
direct measure of the hydrocarbon vapor leak rate.
There are some precautions which must be taken when
applying this sampling method. Since there is a slight positive
pressure (instead of the slight vacuum obtained with the flow-
through method), the tent seal must be leak-free. The tent
65
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seals can be checked for leakage with soap solution (in the
case of cool sources) or the TLV Sniffer can be used to detect
leakage by passing the probe along all tent seals.
The measured quantity in this sampling method is
normally the volume of hydrocarbon leaking from the source. In
order to determine the weight of gas leaking from this source,
the composition and/or molecular weight of the gas must be
known. This can be determined from either the process infor-
mation available from the refinery or from an analysis of the
gas with a gas chromatograph. The mobile laboratory was
equipped with such an instrument.
Baggable Sources - Procedure for Liquid Leaks
For the purpose of this discussion, liquid leaks are
defined as those leaks from which only liquid is observed to
escape. This means that vapor leaks are neither observed vis-
ually nor are they indicated by TLV Sniffer readings of 200
ppm or more at the immediate point of leakage. If the liquid
was of such a volatility as to vaporize rapidly and completely
in the vicinity of the escape point, it was treated as a vapor
leak and bagged.
When a liquid leaks from a source, and some sort of
equilibrium has been established such that there is no net
accumulation at any point, there are basically only three
places for this liquid to go.
(1) it can vaporize into the atmosphere,
(2) it can be absorbed into the ground, and
(3) it can enter the wastewater system
through drains, sewers, or ditches.
66
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Generally, the fate of the liquid is a combination
of two or three of the above possibilities. The more common
probabilities in refineries are (1) and (3). Since the thrust
of this program is aimed at the quantification of emissions to
the air, some means must be used to measure and/or estimate the
amount of material that is ultimately vaporized.
In order to measure the liquid leak rate at the
source, the material was collected in a graduated container.
In the case of hot and/or volatile liquids, the graduated
container was externally cooled with ice and fitted with
covers to contain most of the material. Flow rates were
determined at the leak site by measuring the change in
volume with respect to time.
If the material is not absorbed into the ground or
does not enter the wastewater system, it will all be vaporized
unless a continuous accumulation is occurring. If there was
no net accumulation, the amount being vaporized was assumed
to be equal to the measured liquid leak rate.
Baggable Sources - Procedures for Multiphase Leaks
Multiphase leaks in which one is a liquid hydrocarbon
and others are water and/or water vapor were primarily associ-
ated with pumps and compressors which have water or steam-
jacket devices and drains. The water was condensed and trapped
in the cold trap and did not interfere with hydrocarbon anal-
ysis of the bagged gas.
67
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2.2 Nonbaggable Sources
There are a number of potential hydrocarbon emission
sources in a refinery that are not amenable to sampling with
bags or enclosures. These sources include operations that are
broad in area, intermittant in operation, and/or very complex
in their functioning.
Nonbaggable sources include drainage and wastewater
systems, cooling towers, barometric condensers, removal of coke
from delayed cokers, sampling operations, blind changing, and
maintenance turnarounds. Some of these sources can only be
sampled using very elaborate and complex sampling procedures
and equipment. The sampling of the nonbaggable sources that
could be reasonably sampled will be described in this section.
These sources are the wastewater system and cooling towers.
2.2.1 Nonbaggable Sampling Philosophy
The approach to sampling nonbaggable systems was to
use a mass balance around the particular unit. The difference
between the hydrocarbon into the system (liquid influent) and
hydrocarbon out (liquid effluent) is equal to fugitive emis-
sions to the atmosphere.
The key elements to this approach are collection of
representative samples of liquid streams into and out of a
particular unit and accurate measurement of flow rates through
the system.
Sampling of some units was not done. If the total
hydrocarbon content of the water leaving a treatment unit was
equivalent to or less than 200 Ibs/day or 0.001 percent of the
68
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processed crude oil, whichever was smaller, the remainder of
the downstream wastewater' system was not tested for emissions
of hydrocarbons. Even if all contained hydrocarbons were
emitted as volatile hydrocarbons, the potential for emissions
in the remainder of the system was still small.
Those nonbaggaBle sources that were sampled are dis-
cussed in the following section.
2.2.2 Nonbaggable Source Sampling
Oil-Water Separators
Oil-water separation is normally the first process
that the wastewater encounters as it enters the wastewater
treatment section of a refinery. Oil-water separation can be
accomplished in a surge tank, API separator, or corrugated-plate
interceptor. The API separator is the most widely used of these
three types of separators. The sampling methods described below
for API separators can be applied to the other two types of
units, also.
The inlet liquid to the separator consists of a mix-
ture of hydrocarbon and water. The principal problem encoun-
tered in sampling is the procurement of truly representative
samples of two-phase streams. Samples of each phase were
obtained from the separator inlet line, or from the separator
at a point as close as possible to the oil-water, inlet.
Three streams normally exit from an API separator.
These are the oil that is skimmed from the surface of the liquid
in the separator, the water, and sludge that is pumped from the
bottom of the separator. The sludge was not considered in the
69
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sampling program.' It was assumed to contain low levels of
volatile compounds and to'settle to the bottom. Oil layer
samples were centrifuged to remove sludge particles before
analysis.
The oil that is skimmed from the surface of the
separator is normally pumped to a slop-oil tank. Oil samples*
were preferably taken at the outlet of this pump to insure a
reasonably representative sample. Other sampling points were
the skim pipe itself, the line from the separator to the slop
tank, and the slop tank itself.
In the separator the water flows under a barrier weir
and then over another weir to a basin from which it is pumped
or allowed to flow by gravity to the next processing area in
the wastewater treatment. Water samples were taken at the
overflow weir. Samples were obtained at several points along
the weir, and were composited to form one sample. Factors
which determined the particular sampling point for a given
separator included accessibility, residence time in the.basin,
and presence of sample taps in the pump discharge line.
The average oil outlet rate can be determined from
level readings on the slop-oil tank over given periods of time.
The average outlet oil rate was used to estimate the residence
time in the API separator. The thickness of the oil layer in
the separator, and the dimensions of the area containing the
oil layer also are required in estimating the oil residence
time.
Samples were taken of each stream at each separator
several times a day for several days. Daily samples from each
sample point were composited before analysis. The oil and
70
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water samples from the inlet and outlet of the API separator
were collected in glass bottles. These bottles were completely
filled and kept tightly capped to prevent the escape of vola-
tile hydrocarbons.
Dissolved-Air Flotation Units
If dissolved-air flotation (DAF) units are used in a
refinery wastewater treating system, they usually process water
from the oil-water separators. Air is dissolved or sparged
into the water, and the air bubbles attach themselves -to col-
loidal oil droplets, causing them to rise to the surface,
where the oil-air emulsion is removed.
Some DAF units are partially enclosed and others are
completely open to the atmosphere. The hydrocarbon material
balance method is- the selected technique for determining hydro-
carbon emissions from open units, and may also be used for
partially enclosed units.
Only one stream containing a significant amount of
hydrocarbons enters the DAF unit. This is the water phase from
the oil-water separator. There is normally little free oil in
this water. Ambient air, which may contain low background con-
centrations of hydrocarbons is also injected or sparged into
the water. Three streams leave the DAF unit. These are the
water, the air-oil emulsion and air. All these streams contain
some hydrocarbons.
When applying the material balance method to DAF
units, samples of inlet water were taken. These were normally
the same as the outlet water samples from the API separator,
71
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and the same analysis sufficed for both separator and DAF
hydrocarbon material balances.
In order to close the material balance sufficiently
to calculate hydrocarbon emissions, samples of the outlet water
stream and the air-oil emulsion must also be taken. The outlet
water sample was taken at the overflow weir. The emissions from
air-oil emulsion samples were judged to be negligible contribu-
tors to air emissions.
The water samples were collected several times each
day for several days. The daily samples from each point were
composited for analysis.
Cooling Towers
The selected method for determining hydrocarbon emis-
sions from cooling towers is the hydrocarbon material balance.
Water enters the cooling towers from two sources: make-up
water and the hot water from process exchange. Water, in
significant quantities, leaves as vapor from the top of the
cooling tower, as cooled water returning to process exchange,
and as blowdown. A water material balance shows that the
outlet rate to the process must equal the inlet water rate
from the process, since the make-up water rate is controlled
to exactly balance blowdown plus evaporation.
Thus, if the hydrocarbon content of the incoming hot
water and the return cooled water are known, the evaporative
hydrocarbon emissions can be determined. This is shown in
Figure A2-16.
72
-------
Inlet HaO
Outlet HaO
\
Evaporative Losses
Make-Up HaO
Slowdown
HCIn HaO "*" HC/MU HaO " HCOut HaO "*" HCBD + HCEvaporation
or
^Evaporation " (HCIn H20 " HCOut HaO} " HCBD
or to be specific:
Ib
Evaporative Emissions- (Circulation, GPM) (8.33 -=7) (ppm. -ppm )(10""6)(60)
^3«L XIX OUu
- (Slowdown, GPM) (8.33) (60) (PPm) (10")
Figxire A2-16. Mass Balance Around a Cooling Tower
73
-------
Samples" of inlet and outlet cooling water were
collected daily from each selected tower over a period of
several days. In order to diminish the effect of hydrocarbon
concentration fluctuations, the outlet sample was taken from
the water flowing downward through the tower at a location
just above the level of the cooling tower basin. The inlet
samples were taken from one of the many small sampling valves
which are normally present and branch off the large cooling
water return risers. Many of these are continually flushed
into the tower basin. The hydrocarbon content of the blow-
down stream was assumed to be the same as that of the outlet
water stream.
The samples were kept in sealed bottles under refrig-
eration until they were analyzed.
74
-------
3.0 STACK SAMPLING
Stacks or vents which can be identified as emission
points for hydrocarbons and other criteria pollutants are
classified as process sources. These process sources can be
divided into seven categories:
catalytic cracking unit regenerator
stacks,
boilers and process heater stacks,
sulfur recovery unit or tail gas
treating unit stacks,
compressor engine exhausts,
flares and blowdown systems,
vacuum j et vents, and
* air blowing.
The general strategy regarding the sampling of point
source emissions included sampling the total hydrocarbon emis-
sions, obtaining samples for speciation analysis and sampling
for other criteria pollutants. The methods employed by Radian
for the measurement of stack emissions are discussed in a sub-
sequent section.
The magnitude of the required process source sampling
depended on the size and configuration of the individual refin-
eries as well as the amount of valid data available at each.
75
-------
As a base case, data were taken on one catalytic cracking unit
regenerator stack, one sulfur recovery or tail-gas treating
unit stack, and two process heater stacks.
Measurements made in the base case were: EPA Refer-
ence Methods No. 1, 2, 3, 4, and 5 on all stacks;7 methane and
nonmethane hydrocarbons on all stacks; particulate and vapor
collection for organic characterization on one stack; and,
sulfur gases on the sulfur recovery and/or tail-gas treating
stack.
There were four types of changes to the base case:
sampling for additional stacks
(larger refineries),
sampling of fewer stacks (smaller
refineries),
sampling the base case stacks for
additional species, or
any combination of 1 or 2, and
3 above.
3.1 Process Source (Stack) Sampling - Sampling Trains
Stack sampling procedures are a combination of: EPA
approved methods7 for criteria pollutants (S02, S03, and par-
ticulates); EPA Level I7 screening procedures (S0a, COS, CSa,
HaS, NO, NO . "organic vapor," and Radian-devised methods
/C
(HCN, NH3, THC). The procedures were selected with several
criteria in mind:
76
-------
accepted or proved methodology,
accurate, reproducible measurements,
commercially available equipment,
freedom from interference,
cost-effective trade-off between
sampling and analysis, and
shortest feasible sampling time.
Figures A3-1 through A3-3 depict the sampling trains used.
3.2 Stack Sampling Methods
The characterization of refinery stack emission
involved sampling and analysis for the following species:
particulates total hydrocarbons
SOX fixed gases
trace organic species sulfur species
total aldehydes nitrogen species
The following paragraphs will detail Radian's sampling methods
for each of the above categories of pollutants. A discussion
of sampling schedules and frequency is also included. The
methods used for analysis of these species will be detailed
in a later section.
3.2.1 Particulates
Particulate samples were collected from each stack
according to the procedure described in the EPA Reference Method
57 using a Lear Sigeler, Inc. stack sampling train. Sampling
77
-------
oo
6Z 6%
80% X IPA H202 H202 Silica Gel
\ '
Filler Holder ThermoTneler
S" Type Pilot Tube
i*C*'
Vacuum Line
Cyclone Sal Impingers
Fine Control Valve lc«8a»h
Onlice Gauge
*l Hr~«»
\» Vacuum Gauge
Coarse Control Valve
*w s- Air Tight Pump
Source: Lear Siegler, Inc.. PM 100 - Operation & Maintenance
Manual.
Figure A3-1. Method 5 Train for S0a and Particulates
-------
Teflon/Glass Fiber Filter
Gas !
Sample
Gas
Vent
o
Vacuum Pump
Rotometer/Flow Controller
Figure A3-2. Aldehyde Impinger Train
-------
Gaa Sample
oo
O
I
Stainless Steel
Prr>h<*
A A. UUC
Rotometer/
Flow Controller
Teflon/Class
Fiber Filter
- /ft
; V*
Heated Teflon
Sample Line
Penna Pure Drier
Ti J
Au -u-^
1 t
1
r '
Humid Dry
Air A'lr
,11
Teflon-Line
Vacuum Samp
Pump
r
,
|
R
It
i - /
r
d
le
f ICJ.AHI Dag
(To^al Hydrocarb
> Glass Bomb (NO )
r X
V ClARn Artfff|^
(Sulfur Species)
k. Scotchpak Bag
/ 1? J J r> \
(Fixed Gases)
^ Implngers
(HCN. Nil,)
Figure A3-3. Grab Sample Collection and Preparation System
-------
was performed isokinetically along two perpendicular traverses
of each stack. Duplicate sample runs were made on each stack
insofar as possible. Stacks were sampled that did not meet
Reference Method guidelines for port location. In those cases
the number of traverse points were taken that were felt to be
useful. Figure A3-4 shows the points evaluated on inspection
trips to select stacks to be sampled.
3.2.2 SC)
5C
Oxides of sulfur (S03 and S0a) were collected accord-
ing to EPA Reference Method 8. This was done during each
particulate collection run by passing the filtered sample gases
through an impinger train consisting of an 80 percent isopro-
panol impinger for S03 followed by two 6 percent aqueous
hydrogen peroxide impingers for S0a and a silica gel impinger.
The total mass of water collected in this train was used to
determine the moisture content of the stack gas.
3.2.3 Aldehydes (A)
The aldehyde train (Figure A3-2) used in sampling
stacks consisted of two ice-cooled impingers, each containing
10 ml of a 1.0 percent aqueous sodium bisulfite solution.
Approximately, 12 liters of stack gas were drawn through each
impinger train at a rate of 200 ml per minute. A stainless
steel probe was inserted into the stack to a point of average
velocity, and the gas was transferred to the impinger train
by a small vacuum sampling pump through a heated Teflon sample
line equipped with a Teflon particulate filter. Radian has
found that the use of a heated transfer line is very important
to prevent moisture condensation and subsequent loss of sample
by absorption and dissolution.
81
-------
PORT DIMENSION REQUIREMENTS
(Outside)
ft 3" Max Unless Gate Valve
£Pipe Installed
External Threads for Pipe
Cap Vftion not in Os*
Install Gata Valve if
Stack Contains Dangerous
Gases or Gases Over 200°F
Oncer Positive Pressure
STRENGTH REQUIBEHENTS
SO U>s. Side Load
SO Ibs. Radial' Tension Load
200 Ibs Vertical Shear Load
SAMPLIMC PORTS
A. 2 Ports, 90* Apart
Sight to Ten Stack
Diameters Above Cast
Obstruction
Work Area Clearance
least one Stack. Oianetar
Plus 3' From Stack
^ circuaf eranca
HOME PLATFORM
A. At Least 3' Hide and
Capable- of Supporting 3
People and 200 Ibs. of
Test Equipment
B. Safe Guardrail on Platform
with Access by Safe Ladder
or Other Suitable Means, if
Ladder is Used, Ladder
Must be Loacted at Least
3* froa Ports
C. Ha Obstructions to be
Within 3' Horizontal
Radius on
Platform aeneath
Ports
B.
11SV, ISA,' Single Pbasa,
60 Hz AC (4 Needed for SASS)
Located on Platform and at
Base of Stack with Grounded
Weatherproof Outlet
220V, 30A, Single Phase,
60 Bz AC
This female receptacle nost
be "Hubbell" 73SO or
equivalent, located at base
of stack only.
Figure A3-4. Refinery Inspection Trip - Refinery Stack
Facilities Summary
82
-------
Aldehydes (B)
A second impinger sampling train was sometimes used
to sample for total aldehydes. It consisted of three ice-
cooled impingers, the first containing 10 ml water and the
following two containing 10 ml of 0.05 percent aqueous 3-methyl-
benzothiazolone-hydrazone (MBTH) solution. The aldehydes were
collected by dissolution in the water and reaction with MBTH
to form a water-soluble adduct. Approximately 12 liters of
stack gas were drawn through the impinger train at a rate of
200 ml per minute. Radian has also found that when sampling
combustion gases, it is often necessary to protect the MBTH
impingers by first passing the gas through a water impinger
to scrub out as yet unknown compounds which destroy the MBTH.
As a safety precaution, the scrubber impinger was used during
all sampling runs. The aldehydes collected in this impinger
were determined by adding MBTH to the solution after the
sampling run and analyzing on-site as with the other impinger
solutions.
3.2.4 HCN and NH3
Hydrogen cyanide was collected using the Method 5
stack sampling equipment by passing the filtered sample gases
through three impingers containing 2.0 N sodium hydroxide.
Ammonia was collected similarly using three impingers con-
taining 0.1 N sulfuric acid. In each case sampling was con-
ducted over thirty-minute periods and resulted in approximately
10 SCF of gas for each sample.
83
-------
3.2.5 Grab Samples
The remaining four categories of species are all
collected by grab sampling techniques. From Radian's experi-
ence in sampling for these species in refinery stack gases,
it has been found that collecting and transporting the sample
in a way that preserves its integrity is a nontrivial task.
All of the following factors have been found to contribute to
the nonrepresentativeness and/or degradation of the sample:
sampling equipment construction,
condensation of moisture in the
sample line and vessel,
particulate removal,
sample vessel construction, and
time lag between sampling and
analysis.
Radian has developed a sampling system and operating procedure
which eliminate the negative aspects of all five of the above
factors. A stainless steel probe is inserted into the stack
to the point of average velocity, and the sample gas is drawn
out through a heated Teflon sampling line. The construction
of the sample line is important to prevent moisture condensa-
tion and reaction of the reactive species with any noninert
surfaces. The sample then passes through a heated Teflon
glass/fiber filter to remove particulates followed by a permea-
tion drying system to remove moisture. The Perma-Pure Products,
Inc. multi-tube drier has been found to be effective in removing
84
-------
moisture down to "< 100 ppm while causing only a 1 to 3 percent
loss of the desired species. Without this sample drying tech-
nique, condensation of moisture inside the sample vessels and
the resulting reaction, absorption or dissolution of reactive
species has resulted in poor analyses and complete loss of
sample. Movement of the sample through the system is accomp-
lished by a miniature Thomas vacuum pump equipped with Teflon
heads and diaphragm. The outlet stream from the pump is
directed to the several bags and bombs used to transport the
samples to the field laboratory for analysis. Sampling and
analysis procedures allow no more than 15 minutes elapsed time
between sample catch and start of analysis. If the sample was
not analyzed within that time, a new sample was obtained.
3.2.5.1 Hydrocarbons
Samples for methane and nonmethane hydrocarbon
analysis were collected in 4 liter Tedlar sample bags. Bags
made of aluminized polyethylene have been tried, but substan-
tial sample loss through absorption or reaction was observed.
The Tedlar bags were flushed with zero grade air prior to use.
3.2.5.2 Fixed Gases
Samples for fixed gases (C02, N2, Ha, Oa, CO) anal-
ysis were collected in aluminized Scotchpak sample bags. These
species are quite unreactive and are not prone to absorb onto
the bag walls significantly.
3.2.5.3 Gaseous Sulfur Species
The sulfur species, CSa, HaS, COS, and S0a, proved to
be the most difficult to collect and transport. The two major
85
-------
problems of reaction/dissolution with condensed moisture and
reaction/absorption on the surfaces of the sample vessel were
eliminated by using the sample system (150 ml glass bomb)
described in Figure A3-3.
3.2.5.4 N0x (A)
Samples for NOX were collected in evacuated 2 liter
glass flasks to which had been added 25 ml of a potassium
dichromate-aqueous sulfuric acid solution. The temperature
and pressure of the gas were recorded.
3.2.5.5 NO.. (B)
Samples for NOV were collected in evacuated 2 liter
/s
glass flasks to which had been added 15 ml of chromotropic acid
solution. The temperature and pressure of the gas were recorded.
This method was finally used exclusively because it
appeared to be more reliably accurate than the method described
in Section 3.2.5.4.
36
-------
4.0 . SPECIES'IDENTIFICATION
4.1 Sampling Strategy
4.1.1 Speciation Source Selection
During the sampling for total hydrocarbon emissions a
minimum number of process streams, process emissions, and flue
gas streams were sampled for complete characterization. The
sources were selected for sampling because of their importance/
distribution in the refineries and/or their potential for con-
taining some possibly hazardous compounds.
The location and number of samples collected for
species identification are shown in Tables A4-1 and A4-2.
Within the economic and time limitations of this program, the
sampling scheme provided a reasonably complete basis for esti-
mating the potentially hazardous compounds which might be
emitted from refinery operations. Samples were taken in 13
refineries.
4.1.1.1 Vapor Liquid Compositions of Fugitive Emissions
The relationship between the composition of a vapor
leak and the composition of the stream from which it came was
investigated by taking both liquid and vapor speciation samples
wherever possible. (This was not always possible because not
every stream selected for speciation sampling contained vapor-
leaking sources.)
Vapor samples for speciation analyses were taken by
means of adsorption on a porous polymer. Extraction with an
organic solvent released the adsorbed material for analysis.
87
-------
TABLE A4-1.' SPECIATION SAMPLES - PROCESS STREAMS
Process Unit
Process Stream
Number of
Samples
Crude Distillation
Flashed Crude
Atm. Column Overhead Accumulator Gas
Intermediate Naphtha Product
Full Range Straight Run Naphtha
Virgin Middle Distillate Product
Atmospheric Gas Oil
Light Vacuum Gas Oil
Vacuum Gas Oil
Heavy Vacuum Gas Oil
Vacuum Residuum
1
1
1
1
1
1
1
2
1
1
Fluid Catalytic Cracking
Low Pressure Separator Gas
Low Pressure Separator Liquid
Light Cycle Gas Oil
Heavy Cycle Gas Oil
2
3
2
3
Catalytic Reforming
Recycle Hydrogen Stream
Naphtha Feed
Reformate Product
1
2
6
"Alkylation
Hydrodes ulfuri zation
Crude Alkylate
Product Alkylate
Desulfurized Naphtha Product
Desulfurized Gas Oil
3
1
1
1
Gasoline Sweetening
Solvent Dewaxing
Gas Absorption Unit
Crude Desalting
Mixed Naphtha Feed
Slack Wax
Lean Oil (Naphtha)
Effluent Water
1
1
1
3
API Separator
Surface Oil at Inlet
Surface Oil at Outlet
2
2
Sour Water Stripper
Sour Water Feed
38
-------
TABLE A4-2. SPECIATION SAMPLES - FLUE GAS STREAMS
Process Unit
Flue Gas Stream
Number of
Samples
Fluid Catalytic Cracking
CO Boiler Outlet
Flue Gas Scrubber Outlet
5
1
Thermofor Catalytic Cracking CO Boiler Outlet
Fluid Coking
Scrubber Inlet 1
Scrubber Outlet (CO Boiler Inlet) 2
CO Boiler Outlet 1
Resin Fume Oxidation
Outlet
89
-------
The effect of this technique is removal and concentration of
materials in the hydrocarbon/air mixture.
4.1.1.2 Liquid Samples
Liquid samples taken as speciation samples were drawn
directly from sample lines or ports. In some cases, it was
necessary to pass hot liquid through a cooling coil in an ice
bath as it came out of the line. In this manner, vaporization
of the more volatile constituents was prevented.
4.1.2 Flue Gas Emissions
At each refinery one gas source sample and one par-
ticulate sample were taken from either an FCCU regenerator stack
or CO boiler stack. If more than one FCCU unit were available
at some sites and none were available at others, more samples
were taken at the site with multiple FCCU's.
4.2 Sampling Methodology
4.2.1 Sorbents
For broad boiling range speciation a combination of
sorbent techniques is advisable. For volatile organics from
acetone to naphthalene, Tenax can be used as a sorbent and
thermally desorbed. Benzenes, toluenes and xylenes are the
compounds in the volatility range that would be expected as
fugitives with known adverse environmental effects. Charcoal
tubes are designed to trap components in and above this vola-
tility range. Charcoal tubes are also efficient in the trap-
ping of very volatile emissions, such as vinyl chloride, which
are of interest from a health effects standpoint, but not
90
-------
expected as fugitives from the refining process. To provide a
volatility continuum, charcoal tubes should be used in the
fugitive sampling procedure and the extracts analyzed for any
compounds of interest in the 120°C to 150°C boiling range.
For the high molecular weight fugitives, XAD-2 is recommended
as an adsorbent. Heterocyclic nitrogen and sulfur compounds
and polynuclear aromatic emissions are trapped with the XAD-2
sampling module. Each sorbent system is outlined in the follow-
ing sections.
4.2.1.1 Tenax Adsorbent System
The Tenax tube shown in Figure A4-1 is 1/8 inch O.D.
glass-lined steel which contains approximately 0.8 cc Tenax
and approximately 0.4 cc Davidson #15 silica gel. Most vola-
tile organic species in the boiling range between acetone and
naphthalene may be determined by thermal desorption from Tenax.
Radian has previously measured a variety of volatile organic
species including aromatic and aliphatic hydrocarbons, chlori-
nated hydrocarbons, ethers, esters, acrylates, ketones, chloro-
nitriles, sulfides, mercaptans, nitriles, and alcohols by this
technique. In general, 50- 100 ng of an organic compound sorbed
onto a Tenax tube will give adequate peak size for GC/MS mea-
surement. A lower detection limit of approximately 1 ng is
possible for most organic compounds. If the maximum sample
capacity of the Tenax is limited by the benzene breakthrough
volume of 2 liters, 50 ng of an organic compound with a mole-
cular weight of 100 has a detection level of 6 ppb. Compounds
having less hydrocarbon character, such as alcohols, have
lower breakthrough volumes. Obviously then, a 1 liter sample
with the same constraints yields a 12 ppb detection limit. For
the light aromatics of interest however, 1 ppb is possible with
a corresponding reduction in mass available for quantification.
91
-------
Sample In from Purge
Overall Length: 28 cm
2"
* ' *.
*
*
* **
*
° « 9
» 0
a
o
ao a
VI
.**
- 1"
the tube goes up in the
Tekmar
Che Tenaz
4" Tenax 60 - 80 mesh
2" Oavison Grade 15 Silica Gel
of the silica gel
Flow for Peaorb and Conditioning
Figure A4-1.
Stainless Steel Glass-Lined Tenax-Silica Gel
Purge Traps
92
-------
4.2.1.2 Charcoal Sampling System
A NIOSH method10 describes the collection and analysis
of organic solvents in air. The regulated compounds which are
determined by this method are given in Table A4-3. In Table
A4-3, the standards are expressed as a time weighted average
(TWA) over 8 hours of continuous exposure. The maximum concen-
tration allowable for short time exposures, the ceiling level,
is considered to be the TWA concentration if no other ceiling
level has been determined. Vapors are collected with a portable
personal pump at the flow rates and volumes indicated in the
table.' After the recommended sample has been taken, the char-
coal tube is capped and stored below room temperature to reduce
sample migration. The charcoal is desorbed with CSa in most
cases. Table A4-3 also lists recommended solvents for desorp-
tion. The desorbed sample should be analyzed within 48 hours.
Both the 50 mg and the 100 mg sections are analyzed. If the
backup section has 10 percent or more of the quantity found on
the 100 mg portion, the possibility of sample loss exists and
the sample cannot be quantitated. The charcoal tubes contain
150 mg 20/40 mesh activated coconut charcoal. The front 100 mg
is used for collection, the .remaining 50 mg is used as backup
to determine if breakthrough has occurred.
The advantages of charcoal tubes, in addition to
their convenient size, is that established NIOSH parameters.can
be used for any compound of concern included in the table. The
limitations of the method which must be considered are:
(1) displacement of collected compounds by solvents present in
the atmosphere which are more strongly adsorbed, (2) severe
decreases in breakthrough volume due to high humidity, (3) con-
version of reactive gases to other species on the carbon sur-
face, (4) requirement of numerous tubes for monitoring
93
-------
TABLE A.4-3. OSHA STANDARDS AND SAMPLING PROCEDURES
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100
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94
-------
TABLE A4-3. (Continued)
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95
-------
multicomponent atmospheres, and (5) unproven applicability of
this method to compounds not listed in Table A4-3.
Using GC/MS to quantitate on a desirable 50 ng/
specie-of-interest basis, 450 ppb is an attainable detection
limit for an organic compound with a molecular weight of 120
with a 10 liter breakthrough volume.
4.2.1.3 XAD-2 Adsorbent Systems
For the collection of relatively nonvolatile com-
pounds present in the gaseous phase, XAD-2 can be used. The
collected compounds from the XAD-2 are removed by Soxhlet
extraction with ether, concentrated and quantified by GC/MS.
The resin module was designed using the Arthur D.
Little sorbent evaluation data.11 The ADL data is for low
challenge concentrations (< 100 ppm total hydrocarbons to the
resin) with volatile (BP 120°C) organics.
The advantages of XAD-2 are high adsorption efficien-
cies , effective desorption of polar and high boiling compounds,
low cost and shorter sampling time compared to charcoal tube
sampling using a NIOSH protocol. The disadvantages of using
XAD-2 are that (1) nonpolar compounds boiling below approxi-
mately 140°C may not be retained on the resin, (2) compounds
boiling below approximately 100°C can be lost in the extraction
and concentration steps, and (3) XAD-2 adsorbent often exhibits
a high background (alkyl benzenes, naphthalenes) which interferes
with the quantification of compounds in that range. The cleanup
procedure to reduce the background is time consuming (approxi-
mately one week) and if the resin is broken, more unwashed sur-
faces are exposed to contribute to the background. Breakthrough
96
-------
volumes for the higher boiling compounds trapped by XAD-2 have
not been reported as part' of the ADL sorbent evaluation. How-
ever, the breakthrough volume appears to be 103 2,/g of XAD-2.
The sampling module used was designed for 5 i/min flow and
10 £/min is recommended as a maximum flow rate. This is
equivalent to 600 liters of air containing 15 ppb of a material
having a molecular weight of 150.
In all of the detection limits approximations, the
concentrations are stated as ppb to the sorbent trap.
The utilization of Amberlite XAD-2 resin for sampling
of trace organics in gases requires a rigorous precleaning pro-
cedure to minimize contamination. Radian has developed a pro-
cedure for preparing XAD-2 resin for gaseous sampling.
The resin preparation procedure accomplishes three
basic goals:
* removal of inorganic salts,
removal of organic contaminants, and
storage of resin in a suitable state for
sampling.
The procedure is described in the following steps:
A. The resin as received contains fines and
inorganic salts. Removal of these sub-
stances is accomplished by washing the
resin with water until the water is clear.
97
-------
B. The wet resin is extracted with methanol
in a Soxhlet type extractor for twenty-
four hours. This step serves both to
remove the remaining water and inorganic
salts and to perform an initial removal
of organics.
C. The resin is then extracted for twenty-
four hours with pyridine in a Soxhlet
extractor. This is followed by a twenty-
four hour extraction with diethyl ether.
These extractions remove the remaining
organic contaminants.
D. The resin is then removed from the extrac-
tor and washed with methanol. After wash-
ing, the resin is transferred to a glass
container and'stored under methanol.
The major source of contamination in the resin is
rupturing of the beads after clean-up, releasing organics from
the beads. The procedure described above minimizes this problem
by never allowing the resin to dry or be exposed to excessive
heat and by maintaining a degree of hydration in the resin by
storing under methanol.
Immediately prior to sampling, the resin is trans-
ferred to the resin container, the methanol drained off, and
the resin rinsed with a small amount of organic free water.
Sampling is then performed on the wet resin which may be
returned to the laboratory in this fashion for subsequent
analysis.
98
-------
4,2.2 Collection of Samples
4.2.2,1 Fugitive Emissions
Collection of Leaking Vapor for Species Identifica-
tionSamples of Che leaking vapor were collected on Tenax
adsorbent, XAD-2 resin, and charcoal. The air containing
hydrocarbons from the enclosed leaking valve was passed
through tubes containing the various adsorbents. Both the
"'draw-through" and the "blow-through" methods were used for
this purpose.
The nominal operating conditions for the various
adsorbents are presented in Table A4-4. Before sampling was
started, the hydrocarbon content of the air was determined by
GC. The hydrocarbon loadings on the various adsorbents were
calculated from the sampling time, air flow rate through the
adsorbent, and hydrocarbon content of the air.
The "Blow-Through" MethodSchematic diagrams of the
sampling train used with the "blow-through" method of measur-
ing hydrocarbon emission rates are shown in Figures A4-2a and
A4-2B.
In this method, plant air is used as the source of
diluent air to the enclosure around the leaking source. Plant
air is first passed through an activated carbon canister to
remove contaminants. The air then passes through a dry gas
meter and into the enclosure. The air is exhausted from the
enclosure through a line connected to the opposite side of the
tent. A fraction of the exit air is continually drawn through
an air driven vacuum (sampling) pump. When equilibrium has
been established, this fraction of the air stream is collected
99
-------
TABLE A4-4. NOMINAL OPERATING CONDITIONS FOR SAMPLING WITH ADSORBENTS
Recommended Ranges
Detection Inlet
Sorbent Limit Method Volume Flow Mass Concentration
i
TENAX ~ 1 ppb GC/MS 1 - 2 £ 10-25 ml/min 50 - 100 ng minimum 5-20 ppbv
Charcoal ~ 500 ppb GC/MS 5 - 10 £ 20-50 ml/min 2 - 15 rag 200 - 500 ppmv
~ 50 ppm GC
o XAD-2 ~ 50 - 100 ppb GC/MS 300 -600 I 5-10 1/min 3 - 4 g maximum 100 - 1000 ppmv
o
-------
Plant
Compressed
Air
Activated
Charcoal
Filter
(£$)-* Magnahelic
XAD-2 Resin
Cannlster
Enclosure
Leaking
Valve
Knockout
Flask
Vacuum
Pump
Dry Gas
Meter
XAD-2 Resin
Cannlster
=lxi=
is
-E><
Knockout
Flask
Vacuum
Pump
Dry Gas
Meter
Figure A/j-2a
Typical Sampling Train for Taking Gas Samples on XAD-2 Resin
Using the Blow-Through Method.
-------
Plant
Compressed
Air
Activated
II Charcoal
Filter
====v~7 '
nri|
= UJI|
jnanexic
Tenax or 1
Charcoal Tub el
1
S^ D (
Enclosure-^ f~| 0]
Leaking
Valve
Vacuum
Pump
Bubble Meter
Figure A4-2b. Typical Sampling Train for Taking Gas Samples on Tenax
Resin and Charcoal Using Blow-Through Method.
-------
in a plastic bag." The contents are then analyzed for methane
and total nonmethane hydrocarbon using gas chromatographs
equipped with flame ionization detectors.
The hydrocarbon emission rates can be calculated from
the inlet air flow rate and the hydrocarbon concentration in the
outlet air. The "blow-through" method can be used when very low
or very high flow rates of air are required.
Collection of Samples Using the "Blow-Through" Method
A schematic diagram of the sampling train used to collect vapor
samples on various adsorbents by the "blow-through" method is
shown in Figures A4-2. The XAD-2 resin canisters are large and
contain - 100 gm of adsorbent. A substantial amount of air had
to be passed through a canister to provide enough adsorbent
hydrocarbon for accurate analysis. It was necessary in most
cases, to operate the sampling train for one to two hours for
an adequate XAD-2 resin sample.
Two sample lines were connected to the enclosure out-
let line. Air was drawn through each line with an air-driven
vacuum pump. The flow rate was adjusted to conform to the
operating conditions shown in Table A4-4. The hydrocarbon
concentration of the air was measured by taking air samples
in plastic bags and analyzing the contents by GC to determine
nonmethane hydrocarbon content.
The air flow out the end of the enclosure outlet line
was monitored to insure that a positive flow of air was main-
tained at all times.
A similar system was used to obtain charcoal and
Tenax resin samples. A schematic flow diagram of the system .
103
-------
is shown in Figure A4-2b. Samples of each type were normally
taken. However, the hydrocarbon loading on the charcoal and
Tenax was much lower than that on the XAD adsorbent. The.
individual sampling time was normally 5 to 20 minutes. The
sample air was pulled through the Tenax or charcoal tube with
an air-driven vacuum pump. The required air flow rates were
quite low (see Table A4-4), and a bubble meter was used to set
and measure these rates. The total hydrocarbon adsorbed on the
adsorbent was calculated from the air flow rate through the
tubes, the sampling time, and the hydrocarbon content of the
air.
The "Flow-Through" MethodSchematic diagrams of the
sampling train assembled for "flow-through" sampling are shown
in Figures A4-3a and A4-3b. A Mylar plastic enclosure was made
around the suspected leak. The size of this enclosure was kept
as small as practical,
A continuous flow of air was established by the air-
driven vacuum pump and metered by means of the dry gas meter
and a stopwatch. The temperature and pressure at the meter
were recorded to convert the flow rate to standard conditions.
Once equilibrium was established, a gas sample was withdrawn
by a small sample pump, transferred to a plastic bag and ana-
lyzed for methane and nonmethane hydrocarbon. The hydrocarbon
emission rate was calculated from the air flow rate and the
hydrocarbon concentrations.
Collection of Samples Using the "Flow-Through"
MethodThe "flow-through" method for taking vapor samples on
adsorbents differs from the "blow-through" method in only one
way. Instead of blowing air through the enclosure around the
104
-------
^ MAGNAHEL1C
o
in
XAD-2 RESIN
CANNISTER
XAD-2 RESIN
CANNISTER
LEAKING
VALVE
Figure A4-3a.
VACUUM
PUMP
DRY GAS
METER
Typical Sampling Train for Taking Gas Samples on XAD-2 Resin Using
the Flow-Through Method.
-------
«« MAGNAHEL1C
TENAX OR
CHARCOAL TUBE
=0X1=
VACUUM
PUMP
Q BUBBLE METER
VACUUM
PUMP
LEAKING
VALVE
Figure A4-3b.
Typical Sampling Train for Taking Gas Samples on Tenax Resin and
Charcoal Using the Flow-Through Method.
-------
leaking source, ambient air is drawn into and through the
enclosure with a vacuum pump.
The schematic diagrams of the XAD-2 and the Tenax
resin/charcoal sampling systems are shown in Figures A4-3a and
A4-3b.
Collection of Bulk Liquid SamplesSamples of
various representative liquid streams were collected from
sampling points along the processing lines. All samples
were taken in Pyrex sample bottles, tightly sealed with
Teflon-lined screw caps, and refrigerated until analyzed.
4.2.2.2 Flue Gas and Particulate Sampling
Samples for trace organics speciation were collected
from the selected stack using a modified Aerotherm Source
Assessment Sampling System (SASS). (See Figure A4-4 and
Figure A4-5.) A 1154 SCF sample of stack gas was drawn from
a point of average velocity in the stack. The particulates
were removed on a filter, and the gas was then cooled and
passed through a sorbent canister filled with XAD-2 resin to
trap any nonvolatile organic compounds. The particulates, the
condensate that resulted from cooling the gas, and the XAD-2
resin were collected and returned to Austin for extraction and
analysis.
The organic concentrator for the SASS train is a
canister filled with XAD-2 resin. It replaces the canister
that comes with the SASS train.
Treating Canister Resin--The XAD-2 resin was left in
the methanol solution until ready for treatment. At least six
107
-------
o
CO
STACK T. C.
HEATER
CONTROLLER
CONVECTION OVEN
FILTER
/
-ft
CAS TEMPERATURK T.C.
CONDEHSATB
COLLECTOR
DRY CAS METER OFFICE METER
CENTRALIZED TEMPERATURE
AND PRESSURE READOUT
CONTROL MODULE
CAS COOLER
XAD-2 CABTRIDGB
IMF/COOLER
TRACE ELEMENT
COLLECTOR
Figure A4-4
10 CFM VACUUM PUMP
Source Assessment Sampling System
IMPINCER
T.C.
-------
O
vO
XAO-2 CARTRIDGE
HOT CAS
PROM OVEH
LIQUID PASSAGE
CAS PASSAGE
CAS COOLER
COOL CAS
TO IMPINGER
II
COMPENSATE
RESERVOIR
3-UAY SOLENOID VALVE
*- TO COOLING BATH
FROM COOLING BATH
COOLING FLUID
RESERVOIR
IMMERSION
HEATER
LIQUID PUMP
TEMPERATURE
CONTROLLER
Figure A4-5. XAD-2 Sorbent Trap Module
-------
hours before sampling but not more than twenty-four hours, the
caps were removed from the canister and all the methanol was
drained off. The canister resin (through the end-cap fittings)
was rinsed with - 1500 ml of organic free water. A dry nitro-
gen gas source was fastened to the canister. A flow rate was
controlled between 100 ml to 200 ml per minute.
The canister was heated to 60°C but not more than
100°C to drive off the water. This took approximately four
hours. A mirror was used to test for moisture coming from the
open end of the heated canister. When all water was removed,
the nitrogen flow was stopped and the canister was capped. The
organic concentrator was then ready to be used for sampling.
Attaching Canister to SASS Train--The original equip-
ment organic concentrator was removed from the SASS train;
therefore, the canister was coupled directly to the water trap
reservoir.
Cleaning the Canister--The canister was taken out of
the train and flushed briefly with nitrogen. Both ends were
capped. All fittings other than the canister were rinsed as
described in the Level One procedure12 and the organic solvents
were saved.
4.2.3 Transportation and Storage
At the end of the sampling process, the charcoal and
resin tubes were removed from the sampling system, sealed at
both ends, and placed in a freezer in the mobile laboratory.
They were kept frozen until the 'Sample tubes were processed
for analysis. The liquid samples were sealed in glass bottles
and refrigerated until analyses were performed.
110
-------
When al.l the speciation samples were obtained, they
were sent back to the Radian laboratory in Austin for analysis
on the GC/MS. They were shipped by air freight or hand carried
to Austin where they were, stored in freezers or refrigerators.
Ill
-------
5.0 FIELD ANALYSES
5.1 Mobile Laboratory
Radian had a mobile laboratory dedicated to the
fugitive emission sampling in refineries. This laboratory is
described below. >
The laboratory is housed in an 8' * 26' van trailer
and has the capability of supporting a wide variety of sampling
and analytical procedures. The forward area is equipped with
counter space and utilities to support the wide variety of
analytical instruments contained in .the trailer.
The remainder of the laboratory is equipped with
standard wet-chemistry benches and extensive equipment storage
space. A fume hood, with externally mounted explosion-proof
blowers, has been provided for containment of hazardous experi-
ments and exhaust of vapors. Electrical, water, and drainage
utilities needed to operate the laboratory are obtained on-site,
and external, connections are provided to interface with the
required services. Electric service required is 100 amps at
220 volts single-phase supplied to a junction box equipped to
connect to a 3 wire No. 2 pigtail. Water service can be
supplied by standard high-pressure, three-quarter inch water
hose. The drainage system is adaptable to site requirements.
All external components of the air-conditioning system are
explosion proof.
This trailer was specially equipped for the refinery
sampling program. It contained the primary instrumentation
items:
112
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Hewlett-Packard 5730A gas chromatograph
with duel FID and flame photometric
detectors,
Hewlett-Packard 3380 reporting integrator,
Dohrmann DC 53D Total Organic Carbon
Analyzer,
Byron Model 301C Total Hydrocarbon
Analyzer specially built for Radian,
Monitor Labs chemiluminescent NO/NO
X
analyzer and support equipment,
Wilks Miran 1A portable infrared
analyzer with 21-meter variable path-
length gas cell,
Fisher Gas Partitioner Model 1200 gas
chromatograph,
Bausch and Lomb Spectronic 21 UV-Vis
spectrophotometer,
2 Mettler balances, analytical and
top-loading,
Tracor Model 432 Triperm Permeation
tube calibration system,
complete complement of glassware and
facilities for wet chemistry,
113
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Aerotherm Source Assessment Sampling
Train equipped for high-rate sampling,
particulate size cuts and vapor
collections,
Radian-made aldehyde sampling train,
Lear Siegler PM 100 Manual Stack
Sampler for EPA Method 5,
heated and dehumidified grab sampler
with probe,
two fugitive emission sampling trains
with electric/air-driven pump motors,
dry gas meters, sensitive manometers,
sample take-off valves and cold traps,
and
' Bacharach TLV hydrocarbon sniffers.
5.2 Total Hydrocarbon Content (Methane/Nonmethane)
The analysis for methane and nonmethane hydrocarbon
content of fugitive emission gas samples was accomplished using
a specially designed Total Hydrocarbon Analyzer (THC) Model
301C made for Radian by Byron Instruments. The instrument is
made to accept samples by:
* sampling from a bag,
syringe injection, and
* unattended, continuous in-line sampling.
114
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Analysis of baggable samples of gas was accomplished
by pimping gas out of the- Mylar sampling bag into a gas sample
loop using an integral pump in the THC analyzer. The instru-
ment operates automatically after being connected to the bag.
The results of the first run were discarded to avoid contamina-
tion occurring from sample retained from the previous analysis
or ambient air entering the system during sample changing. Two
additional runs are made and the results recorded by a strip-
chart recorder.
The instrument has several ranges for both methane
and. nonmethane hydrocarbons. The full-scale direct readout
ranges are from 0-2 to 0 - 20,000 ppm by weight. When these
ranges were exceeded, a portion of the sample was diluted with
zero grade air until it could be analyzed on one of the above
ranges. Then the dilution factor was used to calculate the
original concentration.
The THC uses a flame ionization detector for measure-
ment of hydrocarbon concentration and, thus, produces a linear
readout over the entire range of the instrument. Hydrocarbon-
free air is used for the carrier gas.
5.2.1 Theory of Operation of a Flame Ionization Detector
(FID)
When most organic compounds are burned in a hydrogen-
air flame, charged particles or ions are produced. Positive
and negative ions plus free electrons are produced when the
sample passes through the flame. A pair of electrodes with a
polarizing voltage applied collects these ions and the result-
ing current is amplified by an electrometer.
115
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The flame ionization detector is actually an extremely
simple device. All of the essential features are shown in the
figure below.
HYDROGEN:
POLARIZING VOLTAGE
ELECTRODES
ELECTROMETER
TO
RECORDER
>\JET
COLUMN EFFLUENT
Figure A5-1. Flame Ionization Detector
The sample stream is fed to the flame by mixing the
column effluent with the hydrogen supply, and a separate air
stream (not shown) is used to support combustion.
The response (voltage output) varies with the nature
of the compound. The signal on a molar basis is roughly pro-
portional to the number of carbon atoms in the compound.
The response from an FID is proportional to the
weight of solute passing in unit time through the burner and
this is true for hydrocarbons over six orders of magnitude of
concentrations. (See Figure A5-2.)
116
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OS
To6
Concentration
(Arbitrary Units)
Figure A5-2. Area Response Versus Concentration
If one plots response versus molar concentration
(moles/Jl, ppmv, etc.) a family of curves is generated. For a
given response from the detector one must know the identity
of the hydrocarbon in order to find the true concentration
of that specific compound. (See Figure A5-3.)
117
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-------
What do weight response factors look like? Table
A5-1 shows the relative response factors (relative sensitivi-
ties) when equal weights of material are introduced into the
FID. A plot of response versus weight concentration (i.e.,
weight 7o, g/l, ppmW, etc.) generates the same line within a
few percent. Consequently, the specific identity of the
hydrocarbon need not be known. (See Figure A5-4.)
TABLE A5-1. FID RELATIVE SENSITIVITIES
Compound
Normal Parraffins
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Unsaturates
Acetylene
Ethylene
Hexene-1
Octene-1
Decene-1
Relative
Sensitivity
0.97
0.97
0.98
1.09
1.04
1.03
1.00
0.97
0.98
1.07
1.02
0.99
1.03
1.01
Compound
Aromatics
Benzene
Toluene
Ethylbenzene
para-Xylene
meta-Xylene
ortho-Xylene
lM2-Ethylbenzene
lM3-Ethylbenzene
lM4-Ethylbenzene
1,2, 3-Trimethy Ibenzene
1,2 ,4-Trimethylbenzene
1, 3, 5-Trime thy Ibenzene
Isopropy Ibenzene
n-Propy Ibenzene
lM2-Isopropy Ibenzene
lM3-Isopropy Ibenzene
lM4-Isopropy Ibenzene
sec - Butylbensene
tert - Buty Ibenzene
n-Buty Ibenzene
Relative
Sensitivity
1.12
1.07
1.03
1.00
1.04
1.02
1.02
1.01
1.00
0.98
0.97
0.98
0.97
1.01
0.99
1.01
0.99
1.00
1.02
0.98
119
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4)
CO
c
o
a.
CO
All
hydrocarbons
Weight Concentration
Figure A5-4. Area Response Versus Weight Concentration
5.2.2
Quantitative Analysis
The chromatograph gives a voltage output which changes
with time. The simplest device for handling this is the strip
chart recorder, which produces a sheet of paper with an inked
line on it. The easiest thing to measure is the maximum amount
by which the peak departs from the baseline, i.e., peak height.
The advantages of this means of quantitation are speed and
ease. It is, however, subject to many sources of error. Any-
thing which alters the peak shape will create problems.
Area under the curve does not depend on shape. So
long as the same amount of material is injected, even if the
column overloads, the same area will be obtained. Operator
technique variation, assuming the same amount injected, has
essentially no effect on the are figure. Electronic integra-
tion is the best approach for measuring area.
120
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Radian -uses a gas chromatographic instrument that
resolves hydrocarbon mixtures into two peaks. Methane is
separated from all other hydrocarbons and passed through the
FID and then all other hydrocarbons are passed through the
FID simultaneously.
To quantitatively measure methane the following pro-
cedure is used. A known volume of sample of known parts per
million by weight (ppmw) of methane in air is injected into the
analyzer. The peak height is measured. For a single component
peak height is an adequate measure of response. A plot of peak
height versus ppmw then allows any peak height of an unknown
sample to be directly translated into ppmw. The equation of
the line shown in Figure A5-5 is:
peak height
intercept
slope
(slope)(ppmw) + intercept
0, no material^ no response
peak height of standard material
ppmw of standard material
30
1-t
-------
The instrument was calibrated with the standard of known methane
so that the slope was identical from day to day or shift to
shift.
To quantitatively measure the nonmethane hydrocarbons,
a similar procedure was used. A standard of propane of known
ppmw in air was used daily to calculate and keep constant the
slope of a line similar to that of Figure A5-4. (See Figure
A5-6.)
Area Under
Nonmethane
Hydrocarbon
Peak
ppmw Hydrocarbon
Figure A5-6. Peak Area Versus ppmw Hydrocarbon
Since peak shape changes for different hydrocarbons
and the composition in terms of individual hydrocarbons was
unknown for the nonmethane peak, peak area versus ppmw was
used to calculate nonmethane concentrations. The same weight
of any hydrocarbon gave the same peak area (response) within
a very few percent. Therefore:
peak area
(any hydrocarbon)
'peak area propane
pptnw propane
pptnw any hydrocarbon
122
-------
Again Che slope of the line was kept constant from day to day
and shift to shift by using a standard of known concentration
of propane.
Standardization of the THC was accomplished through
a separate gas sampling loop without disconnecting the instru-
ment from the sample being analyzed. The instrument was
standardized every time it was turned on or once per laboratory
shift, whichever was more frequent. The standard contained 100
pptn methane and 100 ppm propane on a molar basis. Repeated
tests against other standards have demonstrated the linearity
of the response of the instrument.
5.2.3 Calculations
The hydrocarbon emission or leak rate from each
sampled source was calculated as a sum of the methane emission
rate, the nonmethane gas emission rate, and the organic con-
densate rate, i.e.,
'where
ET = total hydrocarbon emission rate, Ib/hr,
v ^ methane emission rate, Ib/hr,
E, » condensed organic liquid rate, Ib/hr, and
nonmethane hydrocarbon emission rate, Ib/hr
The emission rates of methane and nonmethane hydro
carbons may be calculated from the following equation:
123
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where
EU = hydrocarbon emission rate, methane and/or
nonmethane, Ib/hr,
K » 2.74 x 10"s , a factor incorporating con-
version factors and standard temperature
and pressure,
Q = flow rate of gas through the sample train,
P = sampling system pressure at the dry gas
meter, psia,
MA = molecular weight of the air/hydrocarbon
mixture, effectively the molecular weight
of air,
GS =* concentration of methane/nonmethane
hydrocarbon in the gas sample from the
sampling train, ppm by weight,
C =» concentration of methane/nonmethane
hydrocarbon in the ambient air, ppm
by weight,
(C -C ) = methane and/or nonmethane concentration
s an.
difference between gas and ambient air,
ppm by weight, and
124
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The organic condensate rate, E^, was calculated from
the following equation:
, 0.115 V
bL t
where ,
E, * organic condensate rate, pounds /hour,
V = volume of condensate collected, ml, and
t = time over which the sample was collected,
min.
This calculation assumes an average density of 0.75
g/cc for the organic condensate. The condensate volume was
measured, and this density was used to calculate the condensate
rate.
5.3 Stack Effluent
Both sulfur gases and particulates are determined by
analysis of components from the EPA-5 train. The procedure for
preparation of the train for sampling is given prior to descrip-
tion of the specific analyses.
Grap samples were taken from the sampling train using
a variety of containers. A description of the preparation of
these sampling containers is also given.
5.3.1 EPA-5 Sampling Train Preparation
The following procedures were used to prepare the
components of the EPA-5 Sampling Train.
125
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Filter -Assembly
1. Dessicate glass-fiber filters for 24 hours,
2. Weigh to the nearest 0.0001 g and place in
a labeled, plastic Petri dish for storage.
3. Transfer one filter to the filter assembly
and record label number and weight on the
field data sheet.
4. Assemble filter and over glassware.
Imp ing er #1
1. Clean and dry a Smith-Greenburg standard
tip impinger.
2. Load with 160 ml 80 percent isopropanol.
3. Weigh entire assembly to ± 0.1 g and
record weight on field data sheet.
Impinger #2
1. Clean and dry a modified Smith-Greenburg
impinger (open tip).
2. Load with 160 ml 6 percent H202.
3. Weigh to ± 0.1 g and record weight.
126
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. Imp ing er #3
1. Clean and dry a Smith-Greenburg standard
tip impinger.
2. Load with 160 ml 6 percent HaOa.
3. Weigh to ± 0.1 g and record.
Impinger #4
1. Clean and dry a modified Smith-Greenburg
impinger.
2, Load with 200 g silica gel.
3. Weigh to ± 0.1 g and record.
5.3.2 Particulates Determination
The total weight of the particulates was determined
from the combined weight of material collected on the filter,
on the exposed surfaces preceeding the filter in the EPA
Method 5 sampling train, and in the first impinger. Procedures
described in EPA Reference Method 51 were used, and a grainload-
ing value was determined based on the total volume of stack gas
sampled. These procedures are discussed below.
Probe Rinse (Prefilter Assembly)
1. Rinse all prefilter pieces with acetone into
previously tared (± 0.0001 g) 250-ml beakers.
127
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2. Combine probe and nozzle rinse from field
with prefil-ter rinse.
3. Cover beakers with aluminum foil with holes
punched in it and allow acetone to evaporate.
Finish drying in oven.
4. Weigh beakers and record weights on field
data sheets.
Filter
1. Disassemble filter, assembly over a clean work
surface.
2. Remove filter from fritted glass plate and
rubber gasket.
3. Transfer to a labeled Petri dish being very
careful not to lose any of the collected
particulate.
4. Carefully scrape all fragments of filter
adhering to 0-ring or glass surfaces onto
top of filter paper in the Petri dish.
5. Dessicate 24 hours.
6. Weight filter paper and all fragments to
nearest 0.0001 g.
7. Record weight on field data sheet.
128
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Imp ing er 1
1. Calculate the amount of NH^OH needed to
neutralize all of the H2SO<. present in
100 ml of sample.
- V X Nt
100
aliquot taken
where
VQ =» average volume in ml used for
aa
sample titration of S03 ,
OH = no-cma-lity of NH^OH, given by:
(7a from bottle) x
17.0 °'9°
Normality = ~ 14.8
VB » volume of blank, ml
N » normality of titrant, and
Aliquot taken = sample size used in the determina-
tion of SO 3.
2. Transfer 100 ml of sample to a 250-ml beaker
tared to the nearest 0.0001 g, and carefully
129
-------
add the calculated volume of NIUOH to
neutralize all H2SO<..
3. Evaporate to dryness and reweigh.
4. Calculate the weight of ammonium sulfate
> present using:
(V_ - V_) 132
S B N
1000 t 2
100
aliquot taken
5. Subtract this value from the net weight of
solids to determine the weight of particu-
late matter in 100 ml of sample.
6. Determine the solids blank by evaporating
100 ml of 80 percent isopropanol from a
tared 250-ml beaker and determining the
weight of the residue.
7. Subtract the blank from the weight of
particulates, then multiply by 4 to get
total particulate catch in the first
impinger.
5.3.3 Sulfur Oxides (SO^)
Separate analyses for S03 and S03 were performed on
the impinger samples collected during each EPA Method 5 train
operation. Aliquots of the isopropanol (S03) and the two
130
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6 percent Ha02(SCT2) impingers were titrated with barium
perchlorate to a Thorin indicator end point as specified in
the EPA Reference Method 8.2 The amount of sulfate found was
used to determine the amounts of S03 and S0a originally
collected from the volume of stack gas sampled.
The S02 and S03 species are collected respectively
in H20a and 80 percent isopropanol in water, as H2SO«,. The
titration involves the complexing of the barium with the S02
and SO3 which forms a precipitate. When the S02 or S03 is
exhausted, the barium then reacts with the Thorin indicator
giving the observed color change.
HaO
S03
H20a HaSO<, + Ba(ClOu) -» BaSO^ + 2HC10<
S0a »
When all S03/S0a is complexed:
Ba**> Thorin * Ba (Thorin)**
(yellow) (peach colored)
Thorin » [ o-(3,6-disulfo-2-hydroxy-l-naphthylazo)-
benzene-arsonic acid]
Reagents
80% Isopropanol
400 ml isopropanol and 100 ml deionized water.
131
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Thorin -Indicator
0.20 g Thorin in 100 ml deionized water.
Barium Perchlorate. ~ Q.Q1 N
1.95 g of Ba(C10J2 3H20 in 200 ml deionized
water. Dilute to one liter with isopropanol.
Sulfuric Acid Standard. - 0.01 N
0.14 ml concentrated HaSO<, in 500 ml deionized
water.
Sodium Hydroxide, ~ 0.01 N
0.040 g NaOH in 500 ml deionized water.
Potassium Acid Phthalate. 0.01 N
0.2041 g KHP in 100 ml deionized water.
Phenolphthalein Indicator
1 g phenolphthalein 95 percent ethyl or
isopropyl alcohol and add 50 ml distilled
water.
132
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Sample Analysis
A. Standardization
L. Standardize the NaOH to ± 0.0002 N against the
KHP using phenolphthalein indicator.
2. Standardize the H2SO«. to 0.0002 N against the
0.01 N NaOH using phenolphthalein.
3. Standardize the Ba(C10<,)a 3H20 with the
0.01 NH2SO<, using Thorin indicator.
B. Impinger 1 - SQ3
Recovery
1. Dry impinger and .wipe off any stopcock
grease.
2. Weigh entire impinger assembly to the
nearest 0.1 g and record weight on field
data sheet.
3. Transfer the liquid to a 500 ml graduate.
4. Determine the amount of 100 percent
isopropanol to be added by:
Final Weight of Impinger
- Tare Weight x 4 = wt isopropanol
133
-------
5. Rinse the impinger assembly with the
calculated amount of 100 percent
isopropanol and add to the graduate.
Mix the solution well.
6. Dilute to the nearest 50 mis with 80
percent isopropanol, making sure that
the final volume is at least 400 mis.
Mix; record the final volume on the
sample container label.
SO3 Titration
1. Determine the aliquot size to be used by
choosing a quantity which requires 20 - 40
mis of titrant. (Try starting with 1-5
ml aliquots and work up.)
2. Pipet the aliquot into an Erlenmeyer flask
and add 2-4 drops of Thorin indicator
solution.
3. Titrate with 'standardized 0.01 N barium
perchlorate to a peach-colored (very
light salmon pink) end point.
4. Record volume of titrant used.
5. Repeat procedure until reproducible
results are obtained.
134
-------
6. Retain the rest of the sample for a
particulate' determination. At least
100 ml must be left.
Blank Titration
1. Pipet the same size aliquot of 80 percent
isopropanol into an Erlenmeyer flask and
add 2-4 drops of Thorin indicator.
2. Titrate as before.
3. Repeat on a second blank sample.
4. Average the results.
C. Impingers 2 and 3 - S03
Recovery
1. Dry and weigh impinger assemblies as with
Impinger 1 and record the weights on the
field data sheets.
2. Transfer contents of each to separate
graduated cylinders. These solutions
will be handled separately in all
succeeding steps.
3. Rinse the connecting tube between Impingers
1 and 2 with deionized water and combine
with the No. 2 solution. Repeat for tube
between 2 and 3 and add to Solution 3.
135
-------
4. Dilute each sample to the nearest 50 mis.
Record the 'final volume on the sample
container label.
SO2 Titration
1. Determine aliquot size to be used. (Try
starting with around 50 ml of sample of
Solution 2.)
2. Pipet this quantity into an Erlenmeyer
flask, add the appropriate amount of 100
percent isopropanol (four times the volume
of the aliquot taken) and 2-4 drops of
Thorin indicator. Titrate as-before.
3. Repeat procedure with Solution 2 until
results are reproducible.
4. Repeat entire procedure with Solution 3.
Blank Titration
1. Pipet the same size aliquot of deionized
80 percent isopropanol in an Erlenmeyer
flask, add Thorin indicator and titrate
as before.
2. Repeat with a second blank sample.
3. Average the results.
136
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Calculations
A. Calculation of S03 Weight
1. To calculate the total weight of S03
present in Impinger 1, the following
equation was used.
(VS-VB) x Nt x MW x 400/aliquot taken
IoooT-2
where
Vg » volume of titrant for sample,
in ml,
Vr, » volume of titrant for blank,
o
in ml,.
Nfc » normality of titrant, and
MW » molecular weight of S03 (80 g/mole)
Aliquot taken given in ml.
2. Report both determinations.
B. Calculation of S02 Weight
1. To calculate the total weight of S02
present in each impinger, use equation
below:
137
-------
(vc~vJ x N x MW x 300/aliquot taken
bB t
1000 x 2
where
MW « molecular weight S02 (64 g/mole).
2. Report both determinations for Impinger 2
and Impinger 3.
5.3.4 Nitrogen Oxides
Nitrogen oxides are converted to nitric acid by the
sorbent solution and the resulting nitrate ion is determined
colorimetrically.
5.3.4.1 Determination of Nitrogen Oxides - Phenoldisulfonic
Acid Method.3
Nitrogen oxides (NO and/or N02, or collectively, NOX)
in stack gas are determined as nitrate (N0~3) colorimetrically.
NO is collected in a glass flow-through type bomb and con-
verted to nitrate ion by reaction with aqueous hydrogen
perioxide which is injected immediately following collection
of the sample. A yellow color is developed at a later time
by the addition of reagents. The color intensity developed
is a function of the concentration of the nitrate. The
intensity is measured using a spectrophotometer capable of
operating at 410 nM.
This method may be used for stack sampling 'With a
varying ratio of NO to N03. Inorganic nitrates, nitrites, and
138
-------
organic nitrogen compounds easily oxidized to nitrate ion may
interfere and give high results. Reducing agents such as S03
and halides may interfere to give lower results. The range of
analysis is from 0.5 yg N0a/ml. of solution to 50.0 yg N0a/ml
of solution.
Instrumentation
A Bausch and Lomb Spectronic 21 spectrophotometer was
used.
Reagents
All reagents should be ACS reagent grade.
A. Potassium Hydroxide (12 N)
Using distilled water, dissolve 673 grams of
potassium hydroxide (KOH) in a 1000 ml volumetric
flask and make up to the mark.
B. Phenoldisulfonic Acid
Dissolve 75 grams of pure phenol in 450 ml of con-
centrated sulfuric acid (HaSOi,). Add 25 ml of
fuming HaSO<, (15 percent free S03). Stir well;
heat for two hours on a steam bath. This reagent
is stable and can be stored for as long as desired.
C. Stock Nitrate Solution
Dissolve 0.4359 grams of anhydrous potassium
nitrate (KN03) in distilled water in a 500 ml
139
-------
volumetric flask. Fill up to the mark. This
solution contains the equivalent of 400 ug NO*/ml.
Dilutions from this are used to make the working
solution.
D. Absorbing Reagent (0.1 M H202 in 0.05 M H2SCU)
>
Prepare by adding 2.8 ml concentrated H2SO<. and
10.0 ml 30 percent H20a to 500 ml deionized water
in a 1000 ml volumetric flask. Dilute to 1.0
liter with distilled or deionized water. (Caution
do not mix acid and peroxide before dilution.)
Preparation of Standard Curve
Place 25 ml of stock nitrate solution in a
porcelain crucible and evaporate to dryness on
a steam bath. Add 2.0 ml of phenoldisulfonic
acid and heat gently on the steam bath until
all residue has dissolved. Using distilled
water, rinse this solution into a 200 ml
volumetric flask and make up to the mark. This
standard solution now contains the equivalent to
50 yg NOa/ml. Pipet 0, 1, 2, 3, 5, 7, 8, and 10
ml of the 50 ug N0a/ml into 50 ml volumetric
flasks. Add 2.0 ml of phenoldisulfonic acid to
each flask and dilute each with approximately
20 ml of distilled water. To each flask add
9.0 ml of KOH (12 N) and make up to 50 ml with
distilled water. The equivalent ug N02/ml in
each volumetric flask is:
140
-------
0 ml ~= 0.0 ug NOj/ml » blank
1.0 ml = 1.0 ug NOa/ml
2.0 ml - 2.0 ug N0a/ml
3.0 ml - 3,0 ug N0a/ml
5.0 ml - 5.0 ug NO2/ml
7.0 ml - 7.0 ug N0a/ml
8'.0 ml - 8.0 ug N0a/ml
10.0 ml - 10.0 ug N0a/ml
Mix thoroughly. Any precipitate formed need not
be filtered out as it settles to the bottom and
should not interfere. (The solution may be
filtered, if desired.) Using 10 mm cuvette,
measure the absorbance of each standard against
the reagent blank at 4LO nM. Plot a curve of
absorbance versus ug N0a/ml.
Sample Analysis
Empty contents of sample bomb into a 100 ml
volumetric flask. Rinse bomb twice with
approximately 10 ml portions of distilled or
deionized water into the volumetric flask.
Add 1.0 N KOH dropwise until sample is
slightly alkaline to litmus paper. Fill to
the mark with distilled water and mix well.
Samples are stable at this point although
they may slowly evolve oxygen. Place.a
10 ml aliquot of this solution in a porcelain
crucible and evaporate to dryness on a steam
bath. Dissolve the residue in 2.0 ml of
phenoldisulfonic acid. Using distilled or
deionized water, rinse this solution into a
141
-------
50 ml volumetric flask and make up to approximately
30 ml. Add 9.0 ml KOH (12 N) and bring the volume
up to 50 ml. Mix thoroughly. Measure the result-
ing absorbance at 410 nM and determine the
Ug NOa/ml from the prepared standard curve.
Calculations
The amount of N0a in the original sample can be
calculated:
_ (ug NOa/ml)(dilution volume)(sample volume)
Ufz NU? s *-j*-«»^-i_^__^«_ ii
e (aliquot volume)
m (ug N0a/ml)(50 ml)(100 ml)
10 ml
Note that N0x is reported as equivalent of N03 .
5.3.4.2 Method for Low Concentrations of Nitrate:
Spectrophotometric Using Chromotropic Acid1*
In this method a 2-ml nitrate sample is mixed with
masking reagents and chromotropic acid indicator in a sulfuric
acid medium.
142
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OH
OH
medium
Yellow Color, Max.
Absorbance = 410 nM
S03H S03H
The absorbance of the yellow reaction product is measured in a
1-cm cell at 410 nM. The nitrate concentration is calculated
by comparing the absorbance to that of a known nitrate standard.
This procedure is designed to measure nitrate ion in
solutions which contain 10 to 60 ppm nitrate.
Ferric ion in excess of 50 ppm and chloride ion in
excess of 2400 ppm (0.07 molar) interfere. Cr*3 in excess of
20 ppm interferes.
Oxidizing substances and nitrite ion are eliminated
by the use of sodium sulfite-urea solution. Suspended solids
which do not dissolve in sulfuric acid interfere and must be
removed by filtration or centrifugation.
The accuracy of this procedure is ± 3 percent for
nitrate concentrations ranging from 0.00016 to 0.0003 molar
(10-20 ppm), and ± 2 percent for the 0.0003 to 0.001 molar
(20 - 60 ppm) range.. Samples containing nitrate concentra-
tions in excess of 0.001 molar (60 ppm) should first be
diluted before this procedure is used. At least one nitrate
standard of similar concentration should be run with the
nitrate samples.
143
-------
The purity factor of the chromotropic acid reagent is
important. The absorbance read for the blank should be less
than 0.018, especially for measuring nitrate concentrations in
the 1-20 ppm range. Better reproducibility is also obtained
when freshly recrystallized chromotropic acid is used.
Instrumentation
. A Bausch and Lomb Spectronic 21 spectrophotometer was
used.
Reagents
A. 10QO ppm Standard Nitrate Stock Solution
Accurately weigh and dissolve 1.371 g of reagent
grade sodium nitrate in about 60 ml of distilled
water. Transfer the solution quantitatively to a
one liter volumetric flask and dilute to volume
with distilled water. This solution will be
used to prepare a standard for comparing nitrate
samples.
B. 20 ppm Standard Nitrate Solution
Pipet 10.00 ml of the 1000 ppm nitrate stock
solution into a 500 ml volumetric flask and
dilute to volume with distilled water. This
solution is convenient for comparing the con-
centrations of nitrate samples.
144
-------
C. Sulfuric Acid
Concentrated reagent grade sulfuric acid is used
in this procedure. It whould be free of nitrate
ion.
Caution!!! Care should be taken when handling
this reagent. Avoid contact with the skin and
clothes. Rinse immediately if spilled.
D. 0.1 Percent Chromotropic Acid Solution
Dissolve 0.18 g of freshly recrystallized
chromotropic acid in 100 ml of concentrated
sulfuric acid. This solution is light sensi-
tive and should be stored in low actinic
bottles. The solution should vary from colorless
to a slight yellow tinge, and is adequately stable
for two weeks.
A detailed procedure for the recrystallization
of chromotropic acid is given at the end of
this section.
E. Sodium Sulfite - Urea Solution
Dissolve 4 g of sodium sulfite and 5 g of urea
in 100 ml of distilled water. This solution
should be mixed on the same day it is used.
F. Antimony Sulfate Solution
Dissolve 1.0 g of antimony metal in 160 ml of
concentrated sulfuric acid by heating and
145
-------
stirring on a hot plate ("- 100°C). Cool and
slowly add the solution to 40 ml of cold
distilled water. Any salt which crystallizes
when, the solution is being stored may be
redissolved by mild heating.
Recrystallization of Chromotropic Acid
The 0.1 percent chromotropic acid solution needed in
the procedure requires purified chromotropic acid. A recrystal-
lization procedure is as follows:
A. Prepare a saturated solution of disodium salt
of 1,8-dihydroxy-3,6-naphthalene disulfonic
acid in distilled water. This may be done by
dissolving 10.0 grams of the above salt in 45
ml of distilled water using a 100 ml graduated
beaker. Mild heating (~ 40°C) and stirring may
be used to hasten dissolution. The resultant
solution is black.
B. Add one or two spatulas of decolorizing charcoal
and stir for five minutes.
C. Using a suction filter, remove the charcoal and
undissolved solids and save the filtrate. The
filtrate will still have a dark color. Care
should be taken not to dilute the filtrate.
D. Add concentrated sulfuric acid dropwise while
stirring in a 100 ml graduated beaker, such that
the temperature remains less than 50"C. The
146
-------
amount of sulfuric acid added should be
35 percent of the original volume.
E. Crystallization will occur within one hour,
and the yield should be about 50 percent of
the original weight dissolved. The beaker
may be cooled in ice water. However, similar
results are obtained if the solution is
allowed to cool at room temperature.
F. Separate the crystals from the supernatant
liquor with a medium-frit, glass suction
funnel (~ 30 ml capacity). Wash the
crystals with reagent-grade ethanol about
four, times or until the filtrate is free
from yellow color.
G. Transfer the crystals to a clean, dry 50 ml
beaker and dry for six hours at 60°C. The
crystals will be finely divided and have a
light gray appearance.
H. Store the dried crystals in a dark bottle.
The time of storage should not exceed two
months unless the precaution is made to
store the crystals in an inert atmosphere.
Sample Analysis
A. Pipet 2.00 ml of nitrate solution (standard
or sample) having a nitrate content in the
range 1-60 ppm into dry 10 ml volumetric
flasks.
147
-------
B. Add 1-2 drops of the sodium sulfite-urea
solution prepared in (5).
C. Add 8-10 drops (0.5 ml) of distilled water
and swirl gently. This step offers an
opportunity to thoroughly rinse the lips of
the volumetric flasks.
Note; The percent water is critical in this
procedure and should range from 27-31 percent
by volume. If the volumetric flasks are not
dry for step (1), then less water should be
added in step (3).
D. Add 2 ml of the antimony sulfate solution and
swirl. Allow the mixture to cool. A tray of
cold water at 10 - 20°C in which the water level
is slightly above that in the flasks may be
used for cooling purposes.
Note: Heat developed during mixing has no
harmful effect. A cooling bath is not neces-
sary if the flasks are allowed to stand at
room temperature for at least 15 minutes.
Care should be taken, however, to dissipate
sufficient heat to avoid boiling of the solutions,
E. Add 1.0 ml of the chromotropic acid solution.
Swirl the flasks again and allow them to cool.
F. Add concentrated sulfuric acid to adjust the
volume to the 10 ml mark, stopper the flasks
and mix the contents by inverting them about
148
-------
four times. Allow the solutions to stand for
45 minutes at room temperature.
Adjust the volume to the 10 ml mark again with
concentrated sulfuric acid. Final mixing should
be done gently so as not to introduce gas
bubble's.
G. The adsorbance reading should be taken 15 minutes
or more after the final adjustment of volume. -
Rinse the 1-cm cell with the solution and then
fill it about 2/3 full. For this operation it
was found expedient to use a 25-ml beaker to
hold the cell in a slanting position with a
ground side facing up and pouring the solution
slowly down the side of the cell. Rinse the
outside of the cell by partially dipping the cell
in a water bath and wiping it with a moist paper
tissue. Place the cap on the cell and wipe clean
with a dry tissue.
Read the absorbance at 410 nM in a suitable
spectrophotometer, using 625 nM as the base line.
A blank (distilled water substituted for nitrate
sample) should also be prepared and used as the
reference cell or read separately.
Calculations
S AS - AB
149
-------
where
Cg = concentration of standard solution
(mg NO",/liter) ,
A., = absorbance of unknown solution
(absorbance units),
A- = absorbance of blank solution
o
(absorbance units) ,
A« = absorbance of standard solution
(absorbance units),
C~ = concentration of nitrate in solution
used (mg/Z).
Calculation for Concentration of N0"3
«.«. MO- cone. NO'S std. (ppm) ., ,. .
ppm NO 3 * TT^z . rr x Abs. of sample
rr Abs. of std. *
ppm NO'
10
» mg of N0"3 in 100 ml sorbent
Calculation for N0.c Concentration in Gas Phase
l io3
ppm N0x = x - (mg N03 found in gas sample)
where
150
-------
(B.-P. ± M.R.) [Vol (flask) - Vol(sorbent) ]
:62,322 (°K)
where
B.P. =» barometric pressure in mm Hg,
M.R. = manometer reading in mm Hg = mm
HaO (1/13.6): positive value if
flask gas pressure is greater
than atmospheric pressure,
negative value if otherwise,
Vol(flask) = volume of gas flask in ml,
Vol(sorbent) = volume of sorbent placed in gas
flask (15 ml),
°K = room temperature in degrees Kelvin,
Example Calculation
B.P. - 740 mm Hg
Temp = 23°C
M.R. - 21.5 mm HaO
Vol flask = 2055 ml
2.0 mg N0~3
B - (740 - 21.5/15.6)(2055-15) .
(62,322)(296) °'°817
151
-------
2 0 x 10^
0.0817 x 62 = 395 ppm N0x
5.3.5 Aldehydes9
The one percent bisulfite impinger solutions were
analyzed using an iodine-starch titration. Samples were
collected, diluted to 50 ml and treated with 10 ml of bisulfite
and 1 ml starch indicator. Any excess bisulfite was then
destroyed with an excess of 0.1 N iodine. The excess iodine
was then destroyed with a few drops of sodium thiosulfate. The
thiosulfate was then titrated to a faint blue endpoint. Addi-
tion of 25 ml of carbonate buffer solution released the com-
plexed bisulfite which was titrated to a final endpoint with
0.01 N iodine.
This procedure measures total aldehydes as formalde-
hyde. One ml of 0.01 N iodine is equivalent to 0.15 mg of
formaldehyde. By accurately measuring the amount of titrant
used in the final titration only, the total mg of aldehyde may
be calculated.
The aldehyde impingers are each filled with 20 ml of
fresh one percent sodium bisulfite. The aldehydes are collected
in the sodium bisulfite solution forming an aldehyde bisulfite
complex. When the sample is assayed, the first step is to
destroy the excess bisulfite with an excess of iodine. The
excess iodine is then destroyed by the addition of thiosulfate
and the thiosulfate is titrated to a faint blue endpoint. Addi-
tion of a carbonate buffer solution releases the complexed
bisulfite which is then titrated to a final endpoint. This
procedure is described by the equations below.
152
-------
NaHS03 + HCHO » H2C . - S03Na
OH
NaHS03 + Ia + HaO * Nal + HaSO<, + HI
4Ia + NaaS203 + 5H20 » 2NaI + 2HaSO<, 4- 6HI
HaC - S03Na + NaaCOs * HCHO + NaaS03
OH
+ NaOH + C0at
* NaaS03 + I, + HaO -» 2NaI -I- H2SO*
Reagents
A. Iodine, 0.1 N (Approximate)
Dissolve 25 g of potassium iodide in about 25 ml
of deionized water. Add 12.7 g of iodine and
dilute to one liter.
B. Iodine, 0.01 N
Dilute 100 ml of the 0.1 N iodine solution to one
liter. Standardize against 0.05 N sodium thio-
sulfate using starch indicator.
C. Sodium Thiosulfate, 0.05 N
Dissolve 1.24 g of sodium thiosulfate in 100 ml
of deionized water.
153
-------
D. Starch Solution, 1 Percent
Make a paste of 1 g of soluble starch and 2 ml of
water. Slowly add the paste to 100 ml of boiling
water. Cool and add a few ml of chloroform as a
preservative. Store in a stoppered bottle.
Discard when mold growth is noticeable.
E. Sodium Bisulfite, 1 Percent
Dissolve 1 g of sodium bisulfite in 100 ml of water.
This should be freshly prepared each week.
F. Sodium Carbonate Buffer Solution
Dissolve 80 g of anhydrous sodium carbonate in about
500 ml of water. Slowly add 20 ml of glacial acetic
acid and dilute to one liter. Store in refrigerator.
Sample Analysis
A. Dilute each sample to a final volume of 50 ml.
B. Pipet a 5 ml aliquot of the sample into a 125 ml
Erlenmeyer flask.
C. Add 10 ml of one percent sodium bisulfite and one
ml of one percent starch solution.
D. Titrate with 0.1 N iodine to a dark blue color.
E. Destroy the excess iodine with a few drops of
0.05 N sodium thiosulfate.
154
-------
F. Add: 0.01 N iodine until a faint blue endpoint
is reached.' (The excess inorganic bisulfite
is now completely oxidized to sulfate. The
solution is now ready for the assay of the
aldehyde bisulfite addition product.)
G. Chill a flask in an ice bath and add 25 ml of
chilled sodium carbonate buffer.
H. Titrate the liberated sulfite with 0.01 N
iodine, using a microburet, to a faint blue
endpoint. The amount of iodine used in this
step must be accurately measured and recorded.
I. Repeat the procedure until reproducible results
are obtained.
J. For each set of samples, a blank should be run
using 5 ml of deionized water.
Calculations
One ml of 0.01 N iodine is equivalent to 0.15 ml of
formaldehyde. Determine the mg of formaldehyde equivalent to
one ml of standardized iodine.
0.01 N m Normality of iodine used (0.01)
0.15 mg Equivalent mg of formaldehyde
(V -V ) x mg x V x 1Q3
Total yg. aldehyde = § §__ S^ T
re J Aliquot Taken
where
155
-------
Vs ^ ml of 0.1 N I used in sample,
VB - ml of 0.01 N I used in blank,
total volume to which sample was
diluted (50 ml) ,
0 " e
-------
3. Prepare hot half of EPA 5 box as with EPA
5 run. It is not necessary to weigh the
filter.
4. Connect impingers and glassware as in EPA
5 run.
Reagents
A. Borate Buffer Solution
Combine 88 ml 0.1 N NaOH with 500 ml 0.025 M
sodium tetraborate and dilute to 1 i. Make
tetraborate solution by dissolving 5.0 g NaaB<,07
or 9.5 g NaaB<.07 10 HaO and dilute to 1 i.
B. Sodium Hydroxide (6N NaOH)
Dissolve 240 g NaOH pellets in 1 A distilled
water.
C. Sodium Hydroxide (IN NaOH)
Dilute one volume 6N NaOH in five volumes
distilled water.
D. Sulfuric Acid (IN HaS04)
Add 28 ml concentrated sulfuric acid to 500 ml
distilled water and dilute to one.
157
-------
E. Pheholphthalein Solution
Dissolve 1 g phenolphthalein in 50 ml 95 percent
ethyl or isopropyl alcohol and add 50 ml distilled
water.
F. Sodium Thisosulfate
Solid Na3Sa03 5H20, C.P., for complexing mercury.
G. Mixed Indicator Solution
Prepare this reagent monthly. Dissolve 200 mg
methyl red indicator in 100 ml 95 percent ethyl or
isopropyl alcohol. Dissolve 100 mg methylene blue
in 50 ml 95 percent ethyl or isopropyl alcohol.
Combine the two solutions.
H. Indicating Boric Acid Solution
Dissolve 20 g H3B03 in distilled water; add 10 ml
mixed indicator solution, and dilute to 1 i. Pre-
pare fresh monthly.
I. Standard Sulfuric Acid Titrant (0.02N)
0.02 N, 1 ml is equivalent to 0.28 mg NH3-N, Dilute
3.0 ml concentrated HaSO<, to 1 I to make approxi-
mately 0.1 N acid. Dilute 200 ml 0.1 N acid to 1 I.
Standardize against 0.05 N Na2C03 prepared by drying
anhydrous sodium carbonate at 140aC for four hours,
cooling in a dessicator, and transferring 2.5 g to
a 1 £ flask and diluting to volume. Take 20 ml
158
-------
of sodium carbonate solution, add about 80 ml
distilled water, titrate with the sulfuric acid
solution to a pH of about 5. Lift out the
electrode, rinse into the beaker, transfer the
beaker to a hot plate, cover with a watch glass
and boil gently for 3-5 minutes. Cool, rinse
watch glass into beaker, and fitfish the titra-
tion to the pH inflection point. Calculate
normality as:
53.0 x c
where
A » g NaaC03 weighed into 1 S.
B = ml NaaC03 used in titration (i.e., 20 ml)
C » ml acid used.
Adjust the acid solution as necessary until
N - 0.020.
Sample Analysis
A. Preliminary Distillation
1. Prior to beginning a set of analyses steam
out the distillation apparatus. Place
500 ml distilled water in a Kjeldhal flask,
add 20 ml borate buffer and a few glass
beads; adjust pH to 9.5 with 6N NaOH. Boil
for about 1/2 hour until the distillate
159
-------
shows no traces of ammonia. Leave the
entire distillation apparatus assembled
until just prior to starting sample
distillation.
2. Use 350 to 500 ml of sample or a portion
diluted to that volume. Add 25 ml borate
buffer and adjust the pH to 9.5 with 6N NaOH.
Check the pH with a meter on every sample.
Some samples may contain high ammonia con-
centrations, in which case adjust the pH
to about 9.7. Check the pH after distilla-
tion to ensure it did not drop below 9.5.
Add several drops of phenolphthalein indicator
to observe pH during distillation; the color
should remain deep red if the pH stays at 9.5.
3. Add 0.2 g sodium thiosulfate if the sample was
preserved with mercury.
4. Transfer the sample to a Kjeldhal flask and
place on the distillation apparatus. Add
50 ml indicating boric acid solution to a 500
Erlenmeyer flask. Place the condenser outlet
tip below the surface of the receiving boric
acid solution.
5. Distill at a rate of 6-10 ml per minute until
250 ml or more of distillate has been collected,
Then lower the distillate until the outlet tip
is free of contact with the distillate and con-
tinue to steam out for about 5 minutes to
cleanse the condenser and delivery tube.
160
-------
6. Leave the Kjeldhal flasks in place until
just prior to running the next set of
samples.
B. Titration
1. Distill samples as described above using
indicating boric acid as an absorbent.
2. Titrate the distillate with 0.02 N HaSO<. to
a pale lavender color. Carry a distilled
water blank through all the steps.
3. The analyst should periodically test pro-
cedures by preparing standard solutions of
ammonium chloride. A recovery of > 97
percent should be expected.
Calculations
II XTTT XT (A-B) X 280
mg/1 NHa-N » -1:* :
ml sample
where
A » ml HaSOfc for sample,
B ml HaSOfc for blank.
5.3.7 Hydrogen Cyanide5
Cyanide in the gas stream is collected by bubbling
the gas through impingers containing sodium hydroxide at a
pH > 12. The resulting impinger solutions are tested for the
161
-------
presence of oxidizing agents, which if found are removed by the
addition of ascorbic acid. The solutions are also tested
for the presence of sulfide, which is precipitated using
lead nitrate and filtered off. An aliquot of sample is then
placed in a cyanide distillation apparatus and an air purge
is applied with a vacuum. The sample is acidified using
sulfuric acid with the resultant off-gases being collected in
a bubbler containing a solution of sodium hydroxide. This
distillation is used to separate CN" from other cyano compounds,
The concentration of CN"in the scrubber solution is then
determined by colorimetric determination using pryidine-
barbituric acid, which forms an intense blue color with free
cyanide. The absorbance is then read and concentrations
determined against standards. These concentrations are calcu-
lated as hydrogen cyanide.
Instrumentation
A Bausch and Lomb Spectromic 21 spectrophotometer
was used.
Reagents
A. Sodium Hydroxide Solution (1.25 N)
Dissolve 50 g NaOH in distilled water, dilute
to 1 z.
B. Magnesium Chloride Reagent
Dissolve 510 g MgCLa 6HaO in. water, dilute
to 1 I.
162
-------
C. Sulfuric Acid. 1:1
Very slowly add 1 part concentrated sulfuric
acid to one part distilled water.
D. Chloramine-T Solution
Dissolve 1.0 g chloramine-T powder in 100 ml
distilled water. Prepare weekly; store in
refrigerator.
E. Stock Cyanide Solution
Dissolve 10 g NaOH and 2.51 g KCN in 1 £ dis-
tilled water. Make this solution fresh each
time a new standard curve is developed. 1 ml =
1 mg CN.
F. Standard Cyanide Solution
Dilute 10.00 ml of stock cyanide solution to 1 i
with 0.25 N NaOH; 1 ml - 10 ug CN. Make a dilu-
tion of 10 ml diluted to 100 ml; 1 ml = 1 ug CN.
Prepare fresh daily.
G. Pyridine-Barbituric Acid Reagent
Place 15 g barbituric acid in a 250 ml volumetric
flask; wash down the sides of the flask with dis-
tilled water, wetting the barbituric acid just
slightly. Add 75 ml pyridine and mix well; add
15 ml concentrated HCI and mix well. Attempt to
dissolve as much of the barbituric acid as possible
163
-------
by vigorous shaking. When cool, dilute to volume
(250 ml) with distilled water. It may be necessary
to let the reagent stand a short while or to warm
the flask slightly by rinsing with hot water to
dissolve all the barbituric acid. When properly
prepared, the reagent should be pale-yellow with
no turbidity. Afterwards, if a precipitate should
develop, make up a new reagent. Store in a dark
bottle and refrigerate; prepare monthly.
H. Sodium Dihydrogen Phosphate, 1 M
Dissolve 135 g NaH2P04 H20 in 1 4 distilled water;
refrigerate.
I. Sodium Hydroxide Solution, 0.25 N
Dissolve 10 g NaOH in 1. i distilled water.
Sample Analysis
The sample preservation procedure consists of raising
the pH to 12.0-12.5. If the sample does not contain excessive
alkalinity, filter (Whatman No. 40 or equivalent), and raise
the pH to 12.0-12.5 with strong NaOH solution or with NaOH
pellets. Any precipitate which forms at this step will
redissolve upon acidification during analysis. If the sample i
does contain high alkalinity (i.e., high total inorganic carbon),
the dissolved C02 must be removed to eliminate interferences
during sample distillation. Raise the pH to 12.0-12.5 with
Ca(OH)2 causing calcium carbonate to precipitate. Let the pre-
cipitate settle, draw off clarified supernatant and filter
164
-------
(Whatman No. 40 or equivalent). Always check sample pH with a
glass electrode or short-range pH paper.
A. Distillation
1. Wash thoroughly, rinse, and assemble the
distillation apparatus.
2. Add 50 ml of 1.25 N NaOH to the gas washer.
Fill to about one inch below the ground glass
joint with distilled water.
3. Ensure that all ground glass joints are
seated well.
4. Turn on the vacuum pump; air will be drawn
into the gas washer via the distillation
flask.
5. Turn on the cooling water.
6. If for some reason samples were not preserved
against sulfide and then filtered, do so now.
7. Measure 250 ml of sample, pour slowly into
the thistle tube, and allow the vacuum to
draw the sample into the distillation flask.
8. Adjust the needle valve to give an air flow
rate of about two bubbles per second entering
the distillation flask.
165
-------
9. Slowly add 50 ml 1:1 H2SO«. through the
thistle tube.
10. Add 20 ml magnesium chloride reagent.
11. Turn power on to the heating mantle. Adequate
refluxing is indicated by 40 - 50 drops per
minute forming from the condenser. Vapors
should not rise more than half way up the
condenser. Avoid excessively vigorous boiling.
12. Reflux for one hour; turn off heat and con-
tinue the air flow for 15 minutes.
13. Turn off the vacuum and drain the scrubbing
solution into a 250 ml (Volumetric) flask.
Rinse the connecting tube and gas washer
with distilled water. Add the rinse water
to the (Volumetric) flask.
14. Dilute the drained fluid to 250 ml with dis-
tilled water. If the solution is not analyzed
immediately for CN, store in the refrigerator
and analyze within four days.
B. Colorimetric Determination
1. Turn on the spectrophotometer and set the wave
length to 578 nM. Allow 'the instrument to warm
up for 15 minutes. Adjust zero absorbance on
the instrument each time it is used by preparing
a reagent blank.
166
-------
2. Take 20 ml of absorption liquid and place in
a 50 ml Nessler tube. The colorimetrie method
is best for samples containing 3 - 9 yg CN in
20 ml. If necessary use a smaller volume of
absorption liquid and dilute to 20 ml with
0.25 N NaOH.
3. Add 15 ml phosphate buffer and invert the
tube to mix well before proceeding to Step 4.
4. Add 2.0 ml chloramine-T solution, and again
invert the tube to mix well, proceed within
30 seconds to Step 5.
5. Add 5 ml pyridine-barbituric acid; invert the
tube and mix well. Mark the time.
6. Add distilled water to give a final volume of
50 ml. Mix well; let the color develop for
exactly 10 minutes.
7. Measure the absorbance at 578 nM against a
reagent blank prepared by taking a 20 ml
sample of 0.25 N NaOH through the color
development procedures.
8. As a quality control measure the distillation
apparatus, reagents, and other potential sources
of error should be periodically tested. A
minimum of 98 percent recovery from a 1 mg/i
CN standard should be expected.
167
-------
C. Standardization
1. Use the 0.25 N NaOH solution to prepare a
blank and to make dilutions; use the stan-
dard 1 ml =» 1 ug CN solution to prepare a
series of standards. Pipet into a series
of six Nessler tubes 0.0 (blank), 2.00,
4.00, 6.00, 8.00, and 10.00 ml of the stan-
dard CN solution. Follow in the same order
with 20.0, 18.0, 16.0, 14.0, 12.0 ml and
10 ml of 0.25 N NaOH to make a series of
20 ml samples.
2. Proceed with Steps 3-7 above using 1 cm
spectrophotometer cells. Plot absorbance
(y-axis, ordinate) against yg CN (x-axis,
abscissa). The slope should be in the
vicinity of 0.065-0.075 per ug.
Calculations
where
A - yg from absorbance curve,
B m total ml absorbing solution used
in the distillation (i.e., 250 ml),
168
-------
C = ml original sample (i.e., 250 ml
unless a smaller portion was used
and diluted to 250 ml) ,
D = ml absorbing solution used in the
color development (20 ml or less).
5.4 Nonbaggable Sample Analyses
5.4.1 Oil
The oil layer samples are assayed by placing 2 ml of
oil into an open container. The sample is stirred for eight.
hours which allows the volatile material in the sample to
evaporate. The volatiles content is represented by the change
in the sample weight over the test period.
Calculation of volatile organics in an oil sample can
be accomplished with the equation below:
A
vo -
wi
where
VO = weight fraction of volatiles in sample,
A = initial sample weight - final sample
weight, .
w. » initial sample weight.
The emission rate of volatile hydrocarbons from oil
can be calculated using the following equation.
169
-------
G(VO, - VO
ER - 1
oil 1 - VC^
where
ER . , = emission rate of hydrocarbon in Ib/hr
G *» flow of weathered oil in Ib/hr,
weight fraction of volatiles in inlet
oil,
VOQ = weight fraction of volatiles in outlet
oil.
5.4.2 Water
Wastewater samples are analyzed for the amount of
purgeable organics. The basis for the analysis is that only
the volatile components in the wastewater collection and
treatment systems will be lost as fugitive emissions. These
volatile compounds comprise the bulk of the purgeable organics
in the liquid.
The purgeable organics are swept out of the water
into a Teflon sampling bag. At the conclusion of the purging
cycle, the contents of the Teflon bag are analyzed on the Total
Hydrocarbon Analyzer as previously described. The equipment
for this analysis is organized as shown in Figure A5-7. The
bag is a standard Teflon sampling bag. The purge gas for the
Bellar unit is zero grade nitrogen with a flow rate of approxi-
mately 30 ml/min. The flow rate is controlled with two needle
valves but will vary slightly from sample to sample and must
170
-------
Tubing
Rubbber Tubing »j
Rubber Cap *(i J
1/8" OD Copper Tubing
a
-------
be measured each "time using a bubble meter on the downstream
side of the Bellar apparatus. Purging is continued for approxi-
mately 30 minutes. The Bellar apparatus requires thorough
cleaning between samples. The Teflon bag must be thoroughly
flushed with zero grade nitrogen between each sample and a
blank sample is analyzed for total hydrocarbons at the end of
the flushing cycle.
The volatile hydrocarbon content of the water can be
calculated from the following equation:
VO - (FR) (time) (ppmw) (Pni- _) (lCTa)
purge
where
VO = volatile organics , grains,
FR = purge flow rate, ml/min,
time =» time of purge, min,
ppmw = concentration of total hydrocarbon
in bag, parts per million by weight,
Ppurge gas ~ density of Pur§e Sas>
The emission rate of volatile hydrocarbons can then
be calculated with the following equation:
500(f )(VO. - vd
ER
water V
172
-------
where
ER at:er = emission rate of hydrocarbon, Ib/hr,
f = flow rate of water through system,
gal/min,
volatile organics in the inlet water
stream, grams,
VO = volatile organics in the outlet water
stream, grams,
V = volume of sample, ml.
s
5.4.3 Total Organic Carbon
Total organic carbon assays were accomplished with a
Dohrmann DC52D TOG Analyzer. This instrument oxidizes organics
to carbon dioxide and then reduces the carbon dioxide to meth-
ane. The methane is measured with a flame ionization detector.
The instrument is zeroed using a "zero carbon water
standard" especially prepared for this analysis by Radian.
The water is deionized, filtered and distilled from potassium
permanganate under helium with a high reflux. This has proven
to be superior to commercial standards. The standard for the
analysis is 180 ppm carbon in water available from Dohrmann.
Several replications of each sample were required
because the size of the portion of the sample actually analyzed
is so small (30 uZ) that it is difficult to obtain a represen-
tative portion.
173
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6.0 SPECIES CHARACTERIZATION
6.1 Organic Species
The measurement of organic species was accomplished
by a combination of experimental methods employing gas chro-
matography and mass spectrometry (GC/MS), as described in the
following subsections.
Samples were collected and analyzed for characteri-
zation of the following:
point source emissions such as CO boiler
regenerator flue gas,
fugitive emissions from valves, pumps,
etc., and
effluent streams from wastewater treatment
processes.
6.1.1 Qualitative Analysis
6.1.1.1 Instrumentation
Analyses for organic species were performed in
Radian's GC/MS laboratory. The instrumentation used is
summarized in Table A6-1.
174
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TABLE A6-1. MASS SPECTROMETERS - RADIAN
Instrument
No.
Type
Haxlaua lonizatlon Sample CC/MS
Resolution Mode* Inlets Interface
SIM*
Data
System
Other Features
Hewlett-Packard
(5982)
1 Quadrapole
Unit El.* CI* GC. ?robe Class jet
or membrane
or direct
Yea Hewlett- Capillary GC, Subamblent GC,
Packard Purge and Trap VOA Analysis
(5933)
Hewlett-Packard
(5985)
1 Quadrapole
Unit El,1 CI* GC, Probe Glass jet
or direct
Yes Hewlett- Capillary GC, Subamblent GC,
Packard Purge and Trap VOA Analysis
(ZIMX-E)
Ui
Hewlett- Disc - Tape Interface digital
Packard tape unit, zeta plotter,
(5934 A) acoustical telephone coupler
'SIM- Selected Ion Monitoring.
2EI Electron lonizatlon.
*CI - Chenlcal lonisation.
-------
6.1.1.2 Extraction
Depending on the sample type and emission source,
different analytical procedures were employed to adequately
measure the organic species. Table A6-2 lists the sample'type
received and the analytical procedures employed for each sample,
Each of these procedures will be described in the following
subsections.
Preliminary Sample Treatment--The analysis of trace
organic species by GC/MS required preliminary sample treatment.
These preliminary steps and their purposes were:
isolation, to remove the organic species
or interest,
separation, to divide the isolated
organic species into groups of similar
chemical or physical properties,
enrinchment, to increase the concentra-
tion of the organic species.
Each of the samples collected during this work
required some or all of these steps as described below.
Isolation of the Organic Species--Removal of the
organic species was performed by two techniques, solvent
extraction and thermal desorption. The thermal desorption
of volatile species from Tenax tubes is an integral part of
the analysis and, as such, will be discussed later.
176
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TABLE A6-2. SUMMARY OF SAMPLE TYPES AND ANALYSIS PROCEDURES
Sample Type Sample Composition Emission Source Analytical Procedure
Process Liquid Organic Liquid Fugitive Pentane Dilution1
XAD-8 Resin Sorted organic vapor Fugitive Pentane Dilution1
Tenax Sorbed organic vapor Fugitive Thermal Desorption
XAD-2 Resin Sorbed organic vapor Point ABN
Particulate - Particulate Point ABN
Effluent Water Aqueous Point Ether extraction
Charcoal Sorbed organic vapor Fugitive CS2 extraction
'Some samples also fractionated on silica gel.
-------
The determination of trace organic species requires
special precautions in the sample preparation. Only high-
purity distilled-in-glass solvents were employed. All labor a.-
tory glassware was cleaned with chromic acid before use.
Immediately prior to use, the glassware was rinsed with an
organic solvent to remove any traces of organic material. Only
Teflon, glass or stainless steel labware contacted the sample.
Aqueous reagents were presaturated with solvent before use.
Isolation of the organic species from the XAD-2 resin
and particulate samples was performed by a 24-hour Soxhlet
extraction with diethyl ether. Diethyl ether was preferred
because:
it has been demonstrated that ether is a
superior solvent for removal of polynuclear
aromatics and other species from XAD-2 resin,
and
any water associated with the resin is
removed by the ether.
The XAD-8 resin samples were Soxhlet extracted with
pentane. A minimum quantity of solvent was employed for the
extraction in order to minimize the loss of volatiles through
concentration. Pentane was also employed as the solvent for
the process liquids. Typically, 1 to 2 grams of sample were
dissolved in 100 ml of pentane.
Aqueous samples were manually extracted with diethyl
ether in a separatory funnel.
178
-------
Thus, at the conclusion of this phase of analysis,
the organic species in each sample had been transferred to a
different matrix as summarixed in Table A6-3. The process
liquid and XAD-8 sample extracts were ready for analysis. The
effluent water sample still required concentration as described
later. The XAD-2 resin and particulate sample extracts were
further separated as described in the following section.
The ABN Separation/Derivitization Scheme--The acid-
base-neutral (ABN) separation strategy was developed by Radian
Corporation for the analysis of complex environmental samples.
The ABN approach is illustrated schematically in Figure A6-1.
The strategy is based on a series of liquid-liquid extractions
that separate a sample into three principal fractions:
A - organic acids whose salts partition
into water at high pH,
B - organic bases whose salts partition into
water at low pH, and
N - neutral hydrophobic compounds.
These principal fractions are then further subdivided
to yield a total of seven fractions which are analyzed by GC/MS.
The ABN extraction procedure was employed to charac-
terize the semi-volatile organic species in the XAD-2 resin and
particulate samples. This separation scheme was chosen on the
basis that (1) the distribution of compounds throughout the
procedure can be predicted with reasonable accuracy, (2) the
procedures do not involve elevated temperatures and (3) the
number of fractions presented for analysis is minimal.
179
-------
TABLE A6-3. SUMMARY OF ISOLATION PROCEDURES
oo
o
SAMPLE TYPE
Process Liquid
XAD-8 Resin
Tenax
ORIGINAL MATRIX NEW MATRIX ADDITIONAL SAMPLE TREATMENT
Organic Liquid Pentane Solution
Polymeric Absorbant Pentane Extract
Polymeric Absorbant Polymeric Sorbant
None
None
None
XAD-2 Resin
Particulate
Effluent Water
Polymeric Absorbant
Particulate
Aqueous
(unchanged)
Ether extract
Ether extract
Ether extract
ABN
ABN
Concentration
-------
OO
CKIIIACI
HEUIHAL AND
ACIDIC
COMfOUNOa
OHOAMC
PllA«t
KKIMACI Wllll
ACIDIC MAICR
AQUEOUS
OAOIC COMPOMNOa
NEUIHAL
COMPOUNDS
BASIFV AND
CKIMACI
Wllll ETIIEN
A. I ACWIC COMPOUNOa
CM 11) AC I Wllll
tnttn
COLUMU
cunouAiounApiiv
ON ailICA OEL
ME1IIVLA1E Wllll
EKIHACr
Wllll E HIEII
CAIiaOMVLIC AClOa
.
I UiaCAHO I
Figure A6-1
ABM Scheme
NON POLAR NEUTRALS
HOD. POLAR NEUTRALS I F.2
| VERV POLAR NEUTRALS
I F-
EiiiEna or
F.5
ACIOIFV.
UE1IIVLAIE
Wllll CII2Ma
EXIRACl
ME1IIVL EGlElia
Of CAIIUOXYLIC
ACIDS
I oiacAoo I
ASIC coupouittia
F.7
F.6
-------
The purpose of the separation scheme was to effect a
sufficient division of organic components so that those com-
pounds of primary interest could be identified and quantitated,
This scheme was not intended to be the ultimate in separations,
and it was not intended that every compound collected in a
particular sample would be isolated and identified.
The complete ABN separation scheme is described in
the subsections below.
Separation of Neutral, Acidic, and Basic Species--The
ether extract of the XAD-2 resin, in particular, was extracted
with three 100 ml portions of five percent HC1 in a separatory
funnel. The combined acidic and neutral extract was then
separated as described later. The pH of the aqueous phase was
adjusted to a pH of 11 with NaOH pellets and then extracted
with three 100 ml portions of ether. This ether extract con-
taining basic species was then concentrated.
The acidic/neutral extract was extracted with three
100 ml portions of five percent NaOH. The remaining neutral
extract was separated while the basic aqueous extract was
extracted and derivatized".
Separation of Neutral Compounds--The ether extract
containing the neutral species was dried by passing it through
a column of sodium sulfate and then concentrated to 1 ml.
Hexane (10 ml) was then added and the sample was reconcentrated
to 5 ml to remove the ether.
Silica gel (E Merck, grade 60, 70-230 mesh) was
fully activated by placing it in an oven at 180°C for four
hours. A small plug of glass wool was placed in the tip of a
182
-------
1 on x 100 on column and the silica gel was transferred while
still hot to a depth of 70 cm. A 1 cm bed of sand was placed
on top of the packed silica gel and 100 ml of dry n-hexane was
added to the column. The hexane was eluted using enough nitro-
gen pressure to give a flow rate of about 5 ml per minute. The
flow was stopped when the solvent level reached the top of the
bed and the quantity of hexane eluted was measured. The void
volume of the column was calculated according to the following
equation:
V * (ml hexane added) - (ml hexane measured)
The hexane concentrate containing the neutral com-
pounds was then transferred to the silica gel column and the
receiver was rinsed with a small volume of hexane which was
added to the column. The reservoir was filled with hexane.
As the solvent level dropped, a total of 5 column volumes was
added. When the solvent reaches the bed, five column volumes
of the next solvent are added after the receiver is rinsed with
small portions of this solvent. In a similar manner, five
column volumes of each succeeding solvent combinations were
added to give a total of four fractions.
The solvents and desired order were:
F-l, Nonpolar neutrals, eluted with hexane,
F-2, Moderately polar neutrals, eluted with
1:1 hexane: methylene chloride,
F-3, Polar neutrals, eluted with 99:1
methylene chloride: methanol, and
183
-------
F-4, Very polar neutrals, eluted with
methanol.
Each fraction was collected and then concentrated.
Separation and Derivatization of Acidic Compound--The
alkaline extract containing the acidic compounds was methylated
in two steps to convert phenols into methyl ethers using
dimethyl sulfate and carboxylic acids into methyl esters using
diazomethane to yield fractions F-5 and F-6 as described below.
The alkaline extract was placed in a 250 ml round
bottom flask and 10 ml of 60 percent NaOH was added. The flask
was heated to 90°C after which time 10 ml of dimethyl sulfate
was added dropwise over a period of ten minutes. After the
addition of dimethyl sulfate, the mixture was stirred for one
hour. After the excess dimethyl sulfate was destroyed by addi-
tion of 5 ml of 50 percent NaOH, the mixture was cooled to room
temperature. The aqueous mixture was then extracted in a
continuous extractor for 24 hours with ethyl ether. The ether
extract containing the ethers of phenols was concentrated to
1 ml.
After extracting the phenol ethers, the alkaline
solution was acidified with 6N HC1 to a pH S 2. This acidic
solution was extracted in a continuous extractor for 24 hours
with ethyl ether. The ethereal extract was concentrated to
about 1 to 2 ml and then transferred to an open hypo-vial.
About 1 ml of a diazomethane solution prepared as described
below was added to the extract concentrate. After swirling
the mixture, more diazomethane was added until a yellow color
persisted. The mixture was allowed to sit for 15 minutes with
occasional swirling. The excess diazomethane was then removed
184
-------
by evaporation on" top of a steam bath. The solution containing
methyl esters of carboxylic acids was concentrated.
Diazomethane was prepared in a special distillation
apparatus that has Clear-Seal joints in place of ground glass
joints to prevent possible explosions (Adrich cat. #210-0250).
The preparative procedure which follows was supplied with this
kit. Twenty-five ml of 95 percent ethanol is added to a solu-
tion of KOH in water (5g in 8 ml) contained in a 100 ml
distilling flask fitted with a dropping funnel and a condenser.
The condenser is connected to two receiving flasks in series,
the second containing 20 to 30 ml of ethyl ether. Both
receivers are cooled to 0°C.
The flask containing the KOH solution is heated in
a water bath to 65 °C and a solution of 21.5g (0.1 mole) of
Diazald in about 200 ml of ethyl ether is added through the
dropping funnel in about 25 minutes. When the dropping funnel
is empty, another 40 ml of ether is added and the distillation
is continued until the distilling ether is colorless. This
distillate contains about three grams of diazomethane.
Concentration of Sample ExtractEach of the sample
extracts generated in this separation scheme were concentrated
before analysis. Radian employed both macro and micro Kuderna-
Danish (K-D) concentrators for this purpose. Typically, an
extract was concentrated to 5-10 ml in a large K-D and then
further concentrated to 1 ml in a micro K-D. An internal
standard, d10-anthracene was then added to each extract at a
known level, typically 200 ppm. All sample concentrates were
stored in crimp-top vials with Teflon-lined seals.
185
-------
6.1.1.3 Identification of Individual Components
Each extract generated as described previously was
analyzed by combined gas chromatography/mass spectrometry
(GC/MS) utilizing either a Hewlett-Packard Model 5982 or a
Hewlett-Packard Model 5985 Computer system. Both capillary
and packed column gas chromatography were employed as described
in the following subsections.
Identification of the chromatographic peaks was
achieved by analysis of the individual mass spectra. Interpre-
tation of mass spectra was performed by three approaches:
manual interpretation of an unknown mass
spectrum,
comparison of the unknown mass spectrum
against the mass spectrum generated from
the analysis of a previously analyzed
standard, or
computer search of the unknown mass
spectrum against libraries containing
reference spectra.
In addition, another technique was utilized to
identify selected organic species at trace levels. This
technique, termed selected ion current profile (SICP) searches,
is based on the appearance of key ions within a narrow reten-
tion time window. This technique was utilized to search for
certain compounds, especially polynuclear aromatic hydrocarbons,
in the extracts. Figure A6-2 presents a SICP search for some
polynuclear aromatics in the ABN Fraction 2 from an XAD resin
186
-------
OO
lint:
SftCI
II
220
I 10
!
j - 1 -- t...l ,.l. . I, ...I , i ,-J - i-.-l ».
1 - 1 I -- I-
111 ri 11 rmrrrmi1 rrn nnrrrri'rriT[i-riT-iinn'ri'i"i'i"ri-i-ri-|-ii-ri"nriTrTT-rri-rii-|-in-i rn-rri 11
» IM IM too tao and >M> IP« «ao son **a ooa aia TOO /»« *oa MO too
llenzutb&kllluorautli'ene 6
1 I'liuiiiiiilliruiio/Aiitlirucuiic
IOD I3O
-------
extract. Identification of the suspected compounds was
confirmed by examination of their mass spectra.
Analysis of ABN Sample Extracts--Each extract from
the ABN separation scheme was analyzed on a six-foot chroma-
tographic column containing one percent SP-2250 on 80/100
Supelcoport. Typically, 2p£ of each sample extract was
injected onto the column.
The GC conditions were as follows: After an initial
hold at 50°C for four minutes, the column was temperature
programmed to 260°C at 8°C per minute. The organic species
which eluted from the gas chromatograph were transferred to
the ion source of the mass spectrometer by means of a glass
jet separator. The mass spectrometer was scanned continuously
from m/e 50 to m/e 350 with a cycle time of three seconds.
Analysis of Process Liquids and XAD-8 Extracts--The
process liquid and XAD-8 extracts were analyzed by capillary
GC/MS employing a special large bore 60 M SP-2100 WOOT
capillary column. The chromatographic and mass spectrometer
conditions were the same as the ABN analysis with 1\ii of each
sample injected.
Analysis of Tenax TubesVolatile species were deter-
mined by thermally desorbing the organics sorbed onto the Tenax
tubes into the GC/MS system. A Tekmar Liquid Sample Concentra-
tor was employed for this purpose. The sample was desorbed by
rapidly heating the Tenax trap to 180°C and passing a helium
flow over the sorbent. The sorbent tube effluent was connected
directly to the head of a cold (- 40°C) gas chromatographic
column. A 9-foot column packed with Carbopack C (80/100 mesh)
coated with 0.2 percent Carbowax 1500, preceded by a one-foot
188
-------
section packed with Chrompsorb W coated with three percent
Carbowax 1500 was employed for this analysis. Quantitative
analysis was achieved by injecting 50 ng of da-toluene in
methanol onto the cold chromatographic column.
The. mass spectrometer was operated in the repetitive
scanning mode, scanning continuously from m/e 45 to m/e 300.
Electron impact (70 eV) ionization was also employed for this
work. After the thermal desorption was completed, the gas
chromatograph was rapidly heated to 60°C. The temperature was
held at 608C for four minutes and then temperature programmed
to 170°C at 4°C per minute. The temperature was held at 170°C
until all of the volatile species had eluted.
6.1.2 Semi-Quantitative Analysis
Semi-quantitative analysis of the identified com-
pounds was achieved by measurement of the area under the
selected ion current profile for each compound. For a given
compound, the area under the most abundant ion was calculated
using the data system. The computed area was then compared
against the area found from the most abundant ion of the
appropriate internal standard, dlo-anthracene or d8-toluene.
The concentration of the species is then calculated using the
following equation:
Ac x ca
Aa x R
where C is the concentration of the component. Ac is the
integrated area of the characteristic ion from the selected ion
current profile, R is the response factor for this component
relative to the internal standard, Aa is the integrated area
189
-------
of the characteristic ion for the internal standard and Ca
is the concentration of the internal standard in the sample.
Radian determined response factors for many compounds
relative to d10-anthracene and da-toluene. Where the response
factor was not known, a value of 1.0 was employed.
Electron impact (70 eV) ionization was employed
exclusively for analyses. The mass spectral information
obtained was stored on a magnetic disc for future interpre-
tation and reference.
6.2 Inorganic Species
Inorganic analyses were performed by Commercial Test-
ing and Engineering using spark source mass spectroscopy.
Spark source mass spectrometer provides an extremely attrac-
tive tool for analysis of inorganic elements other than
carbon, nitrogen, oxygen and hydrogen if great accuracy is not
required. SSMS is not employed for the determination of
mercury (due to high volatility loss). Detection limits for
other elements are of the order of tens of parts per billion
except for heavy elements such as lead, thorium, and uranium,
for which the detection limits are somewhat higher. Mass
spectra are recorded on ion-sensitive photoplates at a nominal
resolution (m/ m) of 5000. Several different exposures of the
same sample are recorded on a given photoplate and the concen-
tration of the elements may be computed by visual interpreta-
tion. Isotope dilution studies can also be made to determine
the concentration of a few elements with extremely high
accuracy.
190
-------
7.0
CONVERSION FACTORS
To Convert From
Btu
bbl
gal
ton
Ibs
cm
ft3
psi
g/gal
Btu/bbl
kWh/bbl
Ib/bbl
lb/106 Btu
grain/ft3
gal/ 10 ft3
gpm
lb/1000 gal
To
kcal
a.
I
kg
kg
in
m3
kg/ cm2
g/*
kcal/Z
kWh/Jl
kg/ SL
g/Mcal
g/m3
i/10sm3
m3/hr
mg/i
Multiple By
0.252
159.0
3.785
907.2
0.454
0.394
0.0283
14.223
0.264
. 0.0016
0.0063
0.0285
, 18.0
2.29
133.7
0.227
119.8
191
yif-
-------
"APPENDIX A: REFERENCES
1. Environmental Reporter. Federal Regulations, Vol. 2,
121:1559-1564. ''".
2. Environmental Reporter. Federal Regulations, Vol. 2,
121:1569-1572.
3. Environmental Reporter. Federal Regulations, Vol. 2,
121:.i567-1572.
4. Martinez.,' J. -L. Summary of Analytical Procedures Used at
the Mbtiave NOV Pilot Unit, Austin, Texas, Radian Corpora-
tion (1975).
5...Environmental Protection Agency. Methods for Chemical
Analysis of Water, and Wastes, EPA 625-/6-74-003, Washing-
. ton, ~D:C., Environmental Protection Agency, Office of
Technology Transfer. (1974).
6. Steigerwald, B. J. Emissions of Hydrocarbons to the
Atmosphere from Seals on Pumps and Compressors. Report
No. 6. Joint District, Federal and State (California) for
the Evaluation of Refinery Emissions (April 1958).
7. Code of Federal Regulations 40, Protection of the
Environment, Parts 60*99, revised edition, Washington,
D.C., .General Services Administration, Office of the
Federal Register (July 1976).
8. Hamersma, J. W., S. L. Reynolds, and R. F. Maddalone.
IERL-RTP Procedures Manual: Level 1 Environmental Assess-
ment. EPA-6007 2-76-160a, EPA Contract No. 58-02-1412.
TRW Systems Group, Redondo Beach, California (June 1976).
-------
9. Texas Air Control Board. Laboratory Methods for
Determination- of Air Pollutants, revised edition,
Austin, Texas (June 1976).
10. National Institute for Occupational Safety and Health.
NIOSH Manual of Analytical Methods, NIOSH Division of
Laboratories and Criteria Development, HEW Publication
No. (NIOSH) 75-121, Cincinnati (1974).
11. Gallant, R. F. , J. W. King, P. L. Levins, and J.; Rf ;.
Piecewicz. Characterization of Sorbent Resins for Use
in Environmental Sampling, EPA-600/7-78-054, March 1978,
Environmental Protection Agency, Industrial Environmental
Research Laboratory, Research Triangle Parkr^NVG;. 27711.
12. Lentzen, D. E., D. E. Wagoner, E.D. Estes, and W. F.
Gutknecht. IERL-RTP Procedures Manual"-: - Level-' 1'.Environmental
Assessment (Second Edition), _EPA-6QO/7-7'8^26lv;Pctober 1978,
Environmental Protection Agency, Ilidustrial. Environmental
Research Laboratory, Research' Triangle Par;k'-, N/.'CV 27711.
193
..sei
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