EPA-450/2-77-036
December 1977
(OAQPS No. 1.2-089)
GUIDELINE SERIES
CONTROL OF VOLATILE
ORGANIC EMISSIONS
FROM STORAGE
OF PETROLEUM LIQUIDS
IN FIXED-ROOF TANKS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Re§earch Triangle Park, North Carolina 27711
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EPA-450/2-77-O3I)
(OAQPS No. 1.2-089)
CONTROL OF VOLATILE
ORGANIC EMISSIONS
FROM STORAGE OF PETROLEUM
LIQUIDS IN FIXED-ROOF TANKS
bv
Emissions Standards and Engineering Division
Chemical and Petroleum Branch
U.S. ENVIRONMENTAL PROTECTION AGENCY
Offire of Aii and Waste Management
Office of Air Quality Planning and Standard*
Rmcarrh Triangle Park. North Carolina 27711
December 1977
ia '
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OAQPS GUIDELINE SERIES
The guideline series of reports is being issued by the Office of Air Quality
Planning and Standards (OAQPS) to provide information to state and local
aii pollution control agencies; for example, to provide guidance on the
acquisition and processing of air quality data and on the planning and
analysis requisite for the maintenance of air quality. Reports published in
this series will be available - as supplies permit - from the Library Services
Office (MD-35), U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina 27711; or, for a nominal fee, from the National
Technical Information Service, 5285 Port Royal Road, Springfield, Virginia
22161. i
Publication No. EPA-450/2-77-036
(OAQPS No. 1.2-089)
11
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TABLE OF CONTENTS
Page
Chapter 1.0 Introduction ..... . . ................ i-i
1.1 Need to Regulate . . . . . .. . . . . . . . . . . ... . . i-V
1.2 Regulatory Approach . . . . . ... . . . . . . . . . . . 1-4
1.3 References . . . . . . . . 1-5
Chapter 2.0 Sources and Types of Emissions .............. 2-1
2.1 Fixed Roof Tanks . . ... . . . . ... . . . . ... . . 2-1
?.2 Emissions 2-3
2.3 References . . . . .... . . . . . ... . . ... . . . 2-5
Chapter 3.0 Control Technology . .... ... . . . . . .... , . . 3-1
3.1 Internal Floating Roof Tank ............... 3-1
3.2 Control Effectiveness . . . . .... ... . . . . . . . 3-4
3.3 References ........................ 3-4
Chapter 4.0 Cost Analysis ....... 4-1
4.1 Introduction. . .... 4-1
4.1.1 Purpose *......,.... 4-1
4.1.2 Scope . 4-1
4.1.^3 Use of Model Storage Tanks . .. . . . . ... . . . 4-1
4.1.4 Bases for Capital and Annualized
Cost Estimates . .......... 4-3
4.2 Control of Emissions from Fixed Roof
Storage Tanks 4-4
iii
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Page
4.2.1 Model Cost Parameters . 4-4
4.2.2 Control Costs . . . 4-4
4.3 Cost Effectiveness . . . . . . . ... . 4-7
4.4 References . .... v 4-14
Chapter 5.0 Effects of Applying the Technology ..... 5-1
5.1 Air Pollution Impacts .................. 5-1
5.2 Other Effects ..;/. 5-1
5.3 Reference ............ .v . . . . . .... ... 5-1
Chapter 6.0 Recommended Regulations, Compliance Test
Method, and Record Keeping ........... 6-1
6.1 Recommended Regulations ....... .... 6-1
6.2 Compliance Test Method . . . . 6-2
6.3 Monitoring and Record Keeping . . . . . . . . ... . . . 6-2
IV
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LIST OF TABLES
Page
Table 2-1 Tank Inventory and Emissions ........ .... 2-4
Table 4-1 Technical Parameters Used in Developing
Control Costs ....................... 4-2
j
Table 4-2 Cost Parameters Used in Computing Control Costs . . . . . .4-5
Table 4-3 Control Cost Estimates for Model Existing
Fixed Roof Tanks . . . . 4-6
Table 4-4 Cost Effectiveness of Controlling Small
Fixed Roof Tank . . V .... 4-8
Table 4-5 Cost Effectiveness of Controlling Medium
Size Fixed Roof Tank . . . . .... . ... . . , . 4-9
Table 4-6 Cost Effectiveness of Controlling Large
Fixed Roof Tank ...................... 4-10
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LIST OF FIGURES
V Page
Figure 2-1 Typical Fixed Roof Tank ....... . .... . ...... 2-2
Figure 3-1 Schematic of Typical Fixed Roof Tank
With Internal Floating Cover . . . . ... 3-2
Figure 3-2 Typical Flotation Devices and Perimeter Seals for
Internal Floating Covers and Covered Floating Roofs . . . . . 3-3
Figure .4-1 Cost Effectiveness of Controlling Emissions
from Existing Fixed Roof Gasoline Tanks ... . . . . . . . - 4-12
Figure 4-2 Cost Effectiveness of Controlling Emissions from
Existing Fixed Roof Crude Oil Tanks ., . . . . . . . ... . 4-13
vi
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ABBREVIATIONS AND CONVERSION FACTORS
EPA policy is to express all measurements in agency documents in
metric units. Listed below are abbreviations and conversion factors for
British equivalents of metric units.
Abbreviations Conversion Factor
1 - liters atm X 101,325 = Pascals
psia X 6,893 = Pascals
liters X .26 = gallons
gallon X 3.79 = liters
kg_ X 1.1 X 10"3 = tons
yr yr
kg - kilograms kilograms X 2.203 = pounds
pounds X .454 = kilograms
Mg - megagram v 10^ gms = 10^ kg
m tons - metric tons tons X .907 = metric tons
m - meters meters X 3.28 = feet
cm - centimeters centimeters = inches X 2.54
kg/103l - kilograms/thousand kg/103liters X 8.33 = lb/103 gal
liters lg/103 gal X .12 = kg/103l
Pa - Pascals 1 kPa = 1000 Pa
kPa - kilo Pascals gallons X 42 = barrels
Frequently used measurements in this document are:
150,000 1 * 40,000 gallons 10.5 kPa ^ 1.52 psia
1,590 X 1031 * 10,000 barrels 560 Mg/yr ^ 617,300 tons/yr
8,750 X 1031 -w 55,000 barrels 134 Mg/yr \ 147,700 tons/yr
23,850 X 1031 ^ 150,000 barrels 56 Mg/yr •>> 61,700 tons/yr
13.8 kPa * 2,0 psia
41.4 kPa A, 6.0 psia
69.0 kPa ^ 10.0 psia
vJi
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Definition of Terms
A. Condensate means hydrocarbon liquid separated from natural gas which
condenses due to changes in the temperature and/or pressure and remains
liquid at standard conditions.
B. Crude oil means a naturally occurring mixture which consists of hydrocarbons
and/or sulfur, nitrogen and/or oxygen derivatives of hydrocarbons and which
is a liquid at standard conditions.
C. Custody transfer means the transfer of produced crude oil and/or condensate,
after processing and/or treating in the producing operations, from storage
tanks or automatic transfer facilities to pipelines or any other forms of
transportation.
D. External floating roof means a storage vessel cover in an open top
tank consisting of a double deck or pontoon single deck which rests
upon and is supported by the petroleum liquid being contained and is
equipped with a closure seal or seals to close the space between the roof
edge and tank shell.
E. Internal floating roof means a cover or roof in a fixed roof tank which
rests upon or is floated upon the petroleum liquid being contained, and
is equipped with a closure seal or seals to close the space between the
roof edge and tank shell.
F- Petroleum liquids means crude oil, condensate, and any finished or
intermediate products manufactured or extracted in a petroleum refinery.
i
G- Petroleum refinery means any facility engaged in producing gasoline,
kerosene, distillate fuel oils, residual fuel oils, lubricants, or other
products through distillation of crude oil, or through redistillation
cracking, extraction, or reforming of unfinished petroleum derivatives.
viii
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True vapor pressure, means the equilibrium partial pressure exerted by a
petroleum liquid as determined in accordance with methods described in
American Petroleum Institute Bulletin 2517, Evaporation Loss from Floating
Roof Tanks, 1962.
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1.0 INTRODUCTION
This document is related to the control of volatile organic compounds
(VOC) from the storage of petroleum liquids. Only storage vessels with
capacities greater than 150,000 liters containing petroleum liquids whose
true vapor pressure is greater than 10.5 kilo Pascals are affected by this
document.
Methodology described in this document represents the presumptive
norm or reasonably available control technology (RACT) that can be applied
to existing fixed roof storage tanks. RACT is defined as the lowest emission
limit that a particular source is capable of meeting by the application of
control technology that is reasonably available considering technological
and economic feasibility. It may require technology that has been applied
to similar, but not necessarily identical, source categories. It is not
intended that extensive research and development be conducted before a
given control technology can be applied to the source. This does not,
however, preclude requiring a short-term evaluation program to permit the
application of a given technology to a particular source. The latter
effort is an appropriate technology-forcing aspect of RACT.
1.1 NEED TO REGULATE
v ' , ^ •-.••• •
Control techniques guidelines concerning RACT are being prepared
for those industries that emit significant quantities of air pollutants
1-1
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in areas of the country where National Ambient Air Quality Standards (NAAQS)
are not being attained. Storage tanks for petroleum liquids are a significant
source of VOC.
EPA promulgated a New Source Performance Standard (NSPS) for storage
of petroleum liquids on March 8, 1974, One provision of the standard
requires that new or modified tanks of capacity greater than 151,412 liters
storing liquids whose true vapor pressure is 10.5 to 76.5 kilo Pascals be
controlled by a floating roof (external or internal) or equivalent.
Preliminary results from an on-going study indicate that combined emissions
- -: l. • ' ' ' ' ., -
from fixed roof and external and internal floating roof storage tanks are about
830 Mg per year. Of these emissions it is estimated that 560 Mg per year
are from fixed roof storage tanks containing petroleum liquids with true vapor
pressures above 10.5 kPa. The magnitude of these emissions indicates the need
) : • ' ' -.-....
for, broader application of the NSPS requirements to existing tanks.
Existing fixed roof tanks with greater than 150,000 liter capacity
containing petroleum liquids with true vapor pressure greater than 10.5 kilo-
Pascals should be controlled hy retrofitting with internal floating roofs or
equivalent: external floating roofs, vapor recovery, vapor disposal systems,
or other equivalent control technology. Bolted tanks generally cannot be
retrofitted with internal floating roofs, and thus will require alternative
equivalent control technology.
The affected facility is the fixed roof storage tank. The recommendations
do not apply to storage tanks equipped with external floating roofs or to
storage tanks having capacities less than 1,600,000 liters used to store
crude oil and condensate nrior to lease custody transfer.
1 2
Field studies that . ive been conducted by Western Oil and Gas Association
and pilot studies conducted by the Chicago Bridge and Iron Company•' * 'are
1-2
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being reviewed to assess the need for more specific regulations dealing with
external floating roofs. It is expected that the analysis will be completed
in 1978.
A study has been initiated to determine emissions from onshore oil
and gas drilling and production. Quantification of emissions from the
storage of produced crude oil and condensate is included. This study
is scheduled for completion in July, 1978. A decision regarding the
need to prepare a guideline document specific to production tanks will be
made ?.t that time.
Cost effectiveness of controlling emissions from fixed roof tanks by
retrofitting with internal floating covers is dependent on tank size,
product type, product value, Dumber of annual tank turnovers^ aoc4. other
factors. For example, the median cost for retrofitting a small 1,590 X 10 liter
fixed roof tank with an internal cover is $15,000. The cost to retrofit
a large 23,850 X 10 liter tank is $57,000. Annual i zed control costs are $3,000
and $11,700, respectively. These costs remain the same regardless of the product
stored. However, cost effectiveness for the small tank can range from a cost
of $240 per Mg of VOC controlled when storing crude oil at low vapor pressure
and low annual turnover, to a credit of $115 per Mg when storing gasoline at
a higher vapor pressure and a higher annual turnover rate. Similarily, the
large tank has a cost effectiveness ranging from a cost of $35 per Mg for
crude oil and a credit of $140 per Mg when storing gasoline.
For some areas it may be reasonable to apply the control strategy to all
fixed roof tanks with a capacity greater than 150,000 liters storing produces
with a true vapor pressure greater than 10.5 kilo Pascals. Nevertheless, the
economic impact on small refiners and small tank operators should be considered.
1-3
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Also not included in the cost effectiveness analysis is the cost of the value
c
of storage capacity lost during retrofit and the hardship that may be created
for the operator who may have only one tank available for storage of a particular
product.
1.2 REGULATORY APPROACH
Mass emission rates for storage tanks are extremely difficult to quantify
because of the varying loss mechanisms and the number of variables affecting
loss rate. As a result it is not possible to develop enforceable performance
standards. Regulations should therefore be written in terms of equipment
specifications and maintenance requirements rather than mass emission rates.
Regular inspections will be required to ensure proper use and maintenance of
control equipment.
1-4
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1.3 REFERENCES
1. Evaluation of Hydrocarbon Emissions From Petroleumj.iquid Storage,
Preliminary Draft Report. Pacific Environmental Services, Inc.
Santa Monica, California, EPA Contract No. 68-02-2606, October, 1977.
A • -
2. Hydrocarbon Emissions From Floating Roof Petroleum Tanks,
Engineering-Sciences Inc., Arcadia, California, for Western Oil and Gas
Association, January, 1977.
3. SOHIO/CBI Floating Roof Emissions Program, Interim Report. October 7, 1976.
SOHIQ/CBI Floating Roof Emissions Program, Final Report, November, 1976.
4. Western Oil and Gas Association, Metallic Sealing Ring Emission Test
Program. Interim Report, Chicago Bridge and Iron Company, January, 1977.
5. Western Oil and Gas Association^ Metallic Sealing Ring Emission Test
Program, Final Report, Chicago Bridge and Iron Company, March, 1977.
6. Western Oil and Gas Association, Metallic Sealing Ring^Emission Test
Program. Supplemental Report, Chicago Bridge and Iron Company, June, 1977.
1-5
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2.0 SOURCES AND TYPES OF EMISSIONS
There are an estimated 26,000 fixed roof storage tanks holding
petroleum liquids at refineries, terminals, tank farms, and along pipelines.
It is estimated that 7,300 of those are storing liquids with true vapor
2 ' •
pressures exceeding 10.5 kPa. These tanks are generally loaded by submerged
(bottom) fill. They are unloaded into tank cars, tank trucks, ships, barges,
or pipelines.
2.1 FIXED ROOF TANKS
Fixed roof tanks consist of a steel cylindrical shell with a permanently
affixed roof (see Figure 2.1). The roof design may vary from cone-shaped
to flat.
Of presently employed tank designs, the fixed roof tank is the least
expensive to construct and is generally considered as the minimum accepted
standard for storage of petroleum liquids. The tank is designed to operate
at only slight internal pressure or vacuum and as a result the emissions
from breathing, filling, and emptying can be appreciable.
Breathing loss is the expulsion of vapor from the tank due to expansion
and contraction resulting from diurnal temperature and barometric pressure
changes. They occur in the absence of any liquid level change in the tank.
Filling losses are associated with an increase of the liquid level in the
tank. Emptying losses occur when air drawn into the tank becomes saturated
2-1
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Figure 2-1 TYPICAL FIXED ROOF TANK
Vent
Thief Hatch
-Manhole
. V .
Nozzle
(For submerged fill
or drainage)
2-2
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with hydrocarbon vapor and expands such that it exceeds the capacity of the
vapor space. Combined filling and emptying losses are called "working losses."
Breather valves (pressure-vacuum) are commonly installed on many fixed
roof tanks to prevent vapors from escaping due to small temperature and barometri<
pressure changes or very small liquid level fluctuations. However, these
valves will vent vapors to the air during normal filling and will draw air
into the tank during emptying.
2.2 EMISSIONS
For petroleum liquids having true vapor pressures above 10.5 kPa,
it is estimated that fixed roof tanks emit about 560 Mg per year of VOC. '
External floating and internal floating roof tanks emit about 134 Mg per year
from liquids having true vapor pressures above 10.5 kPa (see Table 2-1).
For this volatility range, fixed roof tanks comprise forty percent
of the total tank population (over 150,000 1. capacity), or about 7300 tanks.
Fixed roof tanks emit eighty percent of tne total storage losses from the same
volatility and size range.
2-3
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Table 2-1. TANK INVENTORY AND EMISSIONS
1,2
Vapor Pressure Range
kilo Pascals
10.5 to 35.5
35.5 to 62.7
• ,
'
62.7 to 76.5
•
TOTAL
i
Fixed Roof
Tanks Emissions Mg/yr
5,840 406
.
1.396 135
•
49 16
7,285 557
Floating & Internal Floating
Roof
Tanks Emissions Mg/yr
7,093 64
3,357 61
218 9
10,668 134
TOTAL
Tanks Emissions Mg/yr
12,933 470
4,753 196
267 25
17,953 691
ro
1 Includes only tanks with greater than 150,000 1 capacity
2 Calculated from AP-42, Supplement 7, April, 1977
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2.3 REFERENCES
1• Evaluation of Hydrocarbon Emi sslons From Petroleum Ll
Preliminary Draft Report. Pacific Environmental Services, Inc.
'Santa Monica, California, EPA Contract No. 78-02-2606, October, 1977
2. Ibid.
3. Ibid. ','.'..'
4. Ibid.
5. Compilation of Air Pollutant-.Emission Factors, Supplement 7, U. S.
Environmental Protection Agency, April, 1977.
2-5
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3.0 CONTROL TECHNOLOGY
Fixed roof tank emissions are most readily controlled by the installation
of internal floating roofs. This chapter will discuss internal floating
roof tanks.
3.1 INTERNAL FLOATING ROOF TANKS
An internal floating roof tank is essentially a fixed roof tank with
a cover floating on the liquid surface inside the tank, rising and falling
with the liquid level (See Figure 3.1). There are two types of internal
covers: (1) a pan type steel floating roof or (2) a non-ferrous floating
cover. An internal floating roof tank having a steel pan floating roof
is defined as a covered floating roof. If the floating roof is non-ferrous,
as aluminum or polyurethane, it is defined as an internal floating cover.
The fixed roof protects the floating roof and seal from deterioration due to
climatological effects and eliminates the possibility of the roof sinking
because of rain or snow loads-
Whatever the floating roof desiyn, a closure device must be used to
seal the gap between the tank shell and the floating roof around the ,roof
perimeter. Special materials are available for the closure device in a wide
range of designs to accommodate the entire spectrum of petroleum liquids.
Figure 3.2 illustrates several typical flotation devices and perimeter
closure seals for internal floating covers and covered floating roofs.
Other modifications may also be necessary in a fixed roof tank
before equipping it as an internal floating rooi Lank. Tank shell
deformations and obstructions may require correction, special structural
3-1
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FIGURE 3-1
SCHEMATIC.OF TYPICAL FIXED ROOF TANK
WITH INTERNAL FLOATING COVER
Center Venl
Automatic
Tank Gi uge Piping
Step on Tliief Hatch
I.ocat«-d Over S.i mple Well—
Optional Overflow Vent
ti" t S.S. Ground Cables-
Automatic Gauge Float Well
Sample Well
Shell M«n
Roof to
Shell Sea'
Hun I'luti-
Ground Cable Roof Attachment
Anti-Rotation Roof Pitting
Peripheral Roof Vent/
Inspection Hatch
Anti-Rotation Cable Passes
Through Fitting Bolted to Rim Plate
Rim Pontoons
Ami-Rotation Lug Welded to Floor
Tank Support Column with Column Well
Cover Acrew Hatch
Vat imm llrrakcr and Actuator Leg
3-2
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Figure 3-2 - V
Typical Flotation Devices and Perimeter Seals for Internal Floating Covers, and Covered Floating Roof
(A)
INTERNAL FLOATING COVERS
1
(A-l)
Aluminum deck supported above
liquid by tubular aluminum pontoons
(A-2)
Aluminum panel deck supported above
liquid by aluminum floats with polyurethanie^foam
, Elastomer wiper seal
I
CO
^ ill Deck
v { j\ Note: v = vapf r j
L V J L = lint id 0
•'r^u ^ ^ " n°at
\ V I - -A /L "~ "/
,-P — — H -S— - / T -— -/
L L V / . L '
\ *
V x - pontoon • —Pontoon
\ — Metal seal ring
••— . Tank shell (A-3)
Aluminum sandwich panels" with honeycombed
aluminum core floating on surface
^.^...iSanwich pane"^ fj— j /
•:':':'-:'-:'-:^ ] /
Fnam fillpH rnatpd fahrir
(B)
COVERED FLOATING ROOF
Foam filled
/ coated fabric
Steel
Based on Annex A, API Publication 2519, Second Edition
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modifications such as bracing, reinforcing, and plumbing vertical columns
may be necessary. Anti-rotational guides should be installed to keep
cover openings in alignment with roof openings. Special vents are
installed on the fixed roof or on the walls at the top of the shell to
minimize the possibility of VOC's approaching the flammable range in
the vapor space.
3.2 CONTROL EFFECTIVENESS
Calculations indicate that emission reductions of more than 90 percent
are achieved by retrofitting fixed roof tanks with internal floating roofs.
3.3 REFERENCE
1. Compilation of Air Pollutant Emission Factors, Supplement 7, U. S.
Environmental Protection Agency, April, 1977.
3-4
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4.0 COST ANALYSIS
4.1 INTRODUCTION
4.1.1 Purpose
The purpose of this chapter is to present estimated costs for control
of volatile organic compound (VOC) emissions from existing fixed roof
petroleum liquids storage tanks.
4.1.2 Scope
Estimates of capital and annualized costs are presented for controlling
emissions from existing welded steel fixed roof tanks used for storing
petroleum liquids. The cost of control consists of modifying existing tanks
by retrofitting internal floating roofs equipped with closure seals.
Control costs and cost effectiveness ratios are developed for three
model sizes - a small tank with a 15.2 m diameter, a 9.2 m height and a
1590 x 10 1 capacity; a medium size tank with a 30.5 m diameter, a 12.2 m
height and a 8750 x 10^ 1 capacity; and a large tank with a 45.7 m diameter,
a 14.6 m height and a 23,850 x 10 1 capacity. A range of cost effectiveness
ratios are presented for each model size tank for storing gasoline and crude
oil that allow for varying operating conditions and locations of tanks.
4.1.3 Use of Model Storage Tanks
Table 4-1 presents the technical parameters for the three model sizes
of fixed roof petroleum liquids storage tanks. From an inventory of fixed
6 o
roof tanks taken by an EPA contractor, the 1590 x 10 1 tank was selected
• . 3
as representative of small tanks, the 8750 x 10 1 tank was selected as
representative of medium sized tanks, and the 23,850 x 10 1 tank was
selected as representative of large tanks. Emissions before and after
control were calculated.
4-1
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Table 4-1.
TECHNICAL PARAMCmiS USLIJ IN
DEVELOPING CONTROL COSlSa
1. Storage Tank Sues:
Diameter:
Height:
Capacity:
Small
15.2 m
9.2 m
1590
Medium
30.5 m
12.2 w
8750
Large
45.7 m
14.6 in
23,850 m3
1590 x TO3 T 8750 x !03 1 23,850 x 103 1
II, Average Liquid Densities:
Emissions from Gasoline: 671 Kg/m3
Emissions from Crude Oil: i39 Kg/m3
III. Emissions Before Control (Mg/yrj:b
JC. Emissions From Gasolire Storage
No. of Turnovers/Year
True Vapor Pressure kPa
13.8
Small Tank
5
12.0
27.6 22.0
41.4
55.2
69.0
34.0
48.0
68.0
10
15.0
2fi.O
43.0
60.0
83.0
20
21.0
40.0
61.0
84.0
113.0
Medium Tank
5
52
96
145
204
288
1U
68
129
194
325
370
20
101
!95
293
402
-535
'
Large Tank
5
123
229
346
486
498
10
168
359
481
666
903
20
258
499
751
1026
1353
B. Emissions From Crude Oil Storage (Mg/yrj°
Small Tank Medium Tank Larqe Tank
No. of Turnovers/Year
True Vapor Pressure kPa
13.8
27.6
41.4
55.2
69.0
5
6.9
11.8
17.7
25.6
36.5
IV. Emissions After Control (Hg/yr}:°
TO 20
8.8
15.6
23.4
33.2
46.0
12.6
23.2
3«.8
48.4
65.0
b 10 20
28.5
51.9
78.4
110.8
154.3
38.9
72.8
109.7
152.6
206.5
59.9
114.6
172.4
236.2
311.0
5 10
67.5
126
191
267
369
96
183
276
381
511
20
153
297
447
609
796
True Small Tank Medium T*iik Large Tank
Vapor Crude
Crude
Crude
Pressure UPa) Gasoline Oil Gasoline Oil Gasoline Oil
13.8 1.0 0.7 2.9 1.9 5.3 3.4
27.6 1.9 1.2
5.3 3.4 10.0 6.3
41.4 2.9 1.9 8.2 5.3 15.0 9.7
55.2 4.2 2.7 12.0 7.8 22.0 14.2
69.0 6.4 4.1 18.0 11.6 33.0 21.3
Estimated density of condensed vapor emitted from storage tanks.
Reference 1; emissions, calculated per AP-42, Supplement No. 7.
4-2
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Emissions from petroleum liquids vary with true vapor pressure, throughput,
and type of product stored. Gasoline and crude oil have different economic
values and emission rates. In order to allow for typical varying operating
conditions and locations of storage tanks, a range of petroleum credits are
determined using estimated low, median, and high values of the above variables.
Since control costs vary with the size and location of tanks, a range of cost
effectiveness ratios are developed for each of the three model sizes using
estimated low, median, and high control costs. However, actual control costs
may differ from the estimated costs because of the condition and configuration
of the tank(s).
4.1.4 Bases for Capital and Annualized Cost Estimates
Capital cost estimates represent the investment required to purchase
and retrofit the control systems on existing fixed roof storage tanks.
Costs for research and development, cleaning and degassing tanks, correction
of tank defects, loss of use of tanks during retrofit, and other highly
variable costs are not included in the estimates. All capital costs reflect
second quarter 1977 dollars. .-.-,-
Annualized control cost estimates include operating labor, maintenance,
inspections, credits for petroleum savings, and annualized capital charges.
Cost estimates were obtained from an EPA contractor, equipment vendors, an
oil and gas association and an API contractor. Credits for petroleum
savings due to emission control (reduction) have been calculated.
The annualized capital charges are sub-divided into capital recovery
costs (depreciation and interest costs) and costs for property taxes, insurance,
and administration. Depreciation and interest costs have been computed using
4-3
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a capital recovery factor based on a 30 year internal floating roof life
and an interest rate of 10% per annum. Costs for property taxes, insurance,
and administration are computed at 4% of the capital costs. All annualized
costs are for one year periods commencing with the second quarter of 1977.
4.2 CONTROL OF EMISSIONS FROM FIXED ROOF STORAGE TANKS
4.2.1 Model Cost Parameters
Emissions from fixed roof tanks are primarily working losses and
breathing losses. The recommended control technique is to modify fixed
roof tanks by retrofitting internal floating roofs equipped with closure
seals. This control technique is expected to reduce emissions significantly
(see Table 4-1, parts III and IV).
Cost parameters used in computing internal floating roof control
costs are shown in Table 4-2. These parameters are based on actual cost
data from an EPA contractor, equipment vendors, ' an oil and gas association,8
and EPA estimates.
•4.2.2 Control Costs
Table 4-3 presents the estimated costs of controlling VOC emissions from
the three model sizes of existing fixed roof storage tanks. The installed
capital costs are the median industry costs of retrofitting internal
floating roofs, equipped with closure seals, on the three model tanks.
The costs of cleaning and degassing tanks, correction of tank defects and
loss of use of tanks during retrofitting are not included in these costs.
The annual operating and maintenance costs are estimates based on standard
maintenance and inspection programs. The annualized capital charges consist
•4-4
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Table 4-2. COST PARAMETERS USED IN COMPUTING CONTROL COSTS
I. Petroleum Liquid Values:
Gasoline:9 $100.60/m3
Crude Oil:b $73.60/m3
II. . Internal Floating Roof With Closure Seal Values:
A. Installed Capital Cost Retrofitted on Fixed Roof Tank:0
B.
High (North East Coast):
Median (Mid-west):
Low (Gulf Coast):
Annual Maintenance Cost:
Small Tank
$17,000
$15,000
$12,000
Medium Tank
$33,000
$31 ,000
$28,000
Large Tank
$60,000
$57,000
$53,000
5% of installed capital cost plus annual inspection charge of 1%
of installed capital cost.
C. Replacement Life:6 30 years
aAverage gasoline value based on price data from Reference 2 and Wall Street
Journal, October 20, 21, and 24, 1977.
Average crude oil value based on data from Reference 3. Assumes 50% of crude
oil losses will be replaced with imported oil at $91.35/m3 and 50% of losses will
be replaced with domestic oil at actual average price of $53.45/m3. Value also
includes average transportation cost from wellhead or port per Reference 4 of
$1.25/m3.
f* • - ' ' '
Aluminum pontoon type internal floater per Reference 5; retrofitted cost varies with
geographic location because of different labor and transportation costs; costs of
other types of internal floaters will be higher.
Per EPA estimate.
eExpected replacement life per Reference 5.
4-5
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Table 4-3. CONTROL COST ESTIMATES FOR MODEL EXISTING FIXED ROOF TANKS
Control Device
Facility Size
Installed Capital
Annual Operating
Cost ($000) :b
Cost ($000) :a
and Maintenance
Annual ized Capital Charges ($000) :c
Total Annual Control System Cost
(not including petroleum credits)
($000) :d
Internal Floating Roof and Closure Seal
15.2 m diameter
9.2 m height
1590 x 10 I capacity
J5.0
0.9
2.1
3.0
30.5 m diameter
12.2 m height
8750 x 10 1 capacity
31.0
1.8
4.5
6.3
45.7 m diameter
14.6 m height
23,850 x 103 1 capacity
57.0
3.4
8.3
11.7
Median installed costs of retrofitting internal floating roofs and closure seals on existing fixed roof tanks" per
references 5, 6, 7, and 8; does not include the costs of cleaning and degassing tanks, correction of tank defects
and loss of use of tanks during retrofit.
DPer EPA estimate.
"Capital recovery costs (usin-i capital recovery factor with 10 annual interest rate and 30 year internal floating
roof life) plus 4= of installed capital cost for property taxes, insurance, and administration.
d ' ' ' ' ' • •
Sum of annual operating and maintenance cost plus annualized capital charges; but, does not include petroleum
credits (savings).
-------
of the capital recovery costs (using capital recovery factor with 10% annual
interest rate and 30 year internal floating roof life) plus 4% of installed
capital cost for property taxes, insurance, and administration. The total
annual control system costs are the sum of the annual operating and
maintenance costs and the annualized capital charges. Annual petroleum
credits from reducing emissions are not included in these totals, but are
shown in the following section on cost effectiveness.
From Table 4-3, it should be noted that the median capital costs of
internal floatfing roofs retrofitted on the small, medium size, and large
model tanks are $15,000, $31,000 and $57,000, respectively. Also, it may
be seen that the total annual control system costs of the three model tanks
are estimated as $3,000, $6,300, and $11,700, respectively.
4.3 COST EFFECTIVENESS
Tables 4-4, 4-5, and 4-6, present the cost effectiveness ratios of
controlling emissions from the three model sizes of existing fixed roof
tanks. Separate ratios are presented for gasoline and crude oil emission
control because of different economic values and emission rates of the two
liquids. The emission reduction varies with true vapor pressure and
throughput (the number of turnovers). Higher vapor pressure and a larger
throughput will result in a greater quantity of controlled emissions and
larger petroleum credits; opposite (low) values will result in a smaller
quantity of emissions controlled and lesser petroleum savings. Since a
range of the above controlling parameters is needed to cover the typical
range of tank operating conditions and locations, cost effectiveness
ratios have been determined using low, median* and high estimated values
for the factors and control system costs.
4-7
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Table 4-4. COST EFFECTIVENESS OF CONTROLLING SMALL FIXED ROOF TANK
(15.2 m diameter; 9.2 m height;
1590 x 103 1 capacity)
True Vapor Pressure (kPa)
No. of Turnovers/year
Petroleum Liquid Stored
VUt Emission Reduction
(Mg/yr)a.
Annual Petroleum Savings
(Credits) (S000/yr)b
Total Annual Control System
Cost ($000/yr)c
Net Annual Cost/(credit) ($000/yr)d
Cost (credit) per Mg of Controlled
Emissions ($/Mg)e
Low
13.6
5
Gasoline
11.0
(1.7)
2.4
0.7
65
Crude Oil
6.2
(0.9)
2.4
1.5
240
Median
41.4
10
Gasoline
40.1
(6.0)
3.0
(3.0)
(75)
Crude Oil
21.5
(2.9)
3.0
0.1
5
High
69.0
20
Gasoline Crude Oil
107 60.9
(16.0) (8.3)
3.5 3.5
(12.5) (4.8)
(115) (80)
I
00
(Emissions Before Control) minus (Emissions After Control) per Table 4-1.
(VOC Emissions Controlled) x (Recovered Petroleum Liquid Value) * (Average Liquid Density).
Median values from Table 4-3; low and high values based on low and high costs per Reference 5.
Sum of Annual Petroleum Savings (credits) and Total Annual Control System Cost.
e(Net Annual Cost/(credit) r (VOC Emissions Controlled).
-------
Table 4-5. COST EFFECTIVENESS OF CONTROLLING MEDIUM SIZE FIXED ROOF TANK
(30.5 m diameter; 12.2 m height; 8750 x 103 1 capacity)
True Vapor Pressure (kPa)
No. of Turnovers/year
Petroleum Liquid Stored
VOC Emission Reduction
(Mg/yr)*
Annual Petroleum Savings
(credits) ($000/yr)b
Total Annual Control System
Cost ($000/yr)c
Net Annual .Cost/(credit)
($000/yr)d
Cost (credit) per Mg of
Controlled Emissions ($/Mg)e
Low
13.8
5
Gasoline
49.1
(7.4)
5.7
(1.7)
(35)
Crude Oil
26.6
(3.6)
5.7
2.1
80
Median
41.4
10
Gasoline
186
(27.9)
6.3
(21.6)
(115)
Crude Oil
104
(14.2)
6.3
(7.9)
(75)
High
69.0
20
Gasoline Crude Oil
517 299
(77.6) 140.9)
6.8 6.8
(70.8) (34.1)
(135) (115)
(Emissions Before Control) minus (Emissions After Control) per Table 4-1.
(VOC Emissions Controlled) x (Recovered Petroleum Liquid Value) t (Average Liquid Density).
cMedian values from Table 4-3; low and high values based on low and high costs per Reference 5.
Sum of Annual Petroleum Savings (credits) and Total Annual Control System Cost.
e(Net Annual Cost/(credit) t (VOC Emissions Controlled).
-------
Table 4-6. COST EFFECTIVENESS OF CONTROLLING LARGE FIXED ROOF TANK
(45.7 m diameter; 14.6 m height; 23,850 x 103 1 capacity)
True Vapor Pressure (kPa)a
No. of Turnovers/year
Petroleum Liquid Stored
VOC Emission Reduction
(Mg/yr)a
Annual Petroleum Savings
(Credits) ($000/yr)b
Total Annual Control System
Cost ($000/yr)c
Net Annual .Cost/ (credit)
($000/yr)d
Cost (credit) per Mg of Controlled
Emissions ($/Mg)e
Low
13.8
5
Gasoline
118
(17.7)
10.9
(6.8)
(.60)
Crude Oil
54.1
(8.7)
10.9
2.2
30
Median
41 .4
10
Gasoline
466
(69.9)
11.7
(58.2)
(125)
Crude Oil
266
(36.3)
.11.7
(24.6)
(90)
High
69.0
20
Gasoline Crude Oil
1320 775
(198.0) (105.7)
12.4 12.4
(185.6) 1 93.. 3)
(140) (120)
I
o
a(Emissions Before Control) minus (Emissions After Control) per Table 4-1.
(VOC Emissions Controlled) x (Recovered Petroleum Liquid Value) * (Average Liquid Density).
'•Median values from Table 4-3; low and high values based on low and high costs per Referenced.
Sum of Annual Petroleum Savings (Credits) and Total Annual Control System Cost.
e(Net Annual Cost/(credit) * (VOC Emissions Controlled).
-------
From Table 4-4, it can be observed that the cost effectiveness of
the small model tank varies from a credit of $115 to a cost of $65 per Mg
of controlled gasoline emissions. The corresponding cost effectiveness
ratios for crude oil emission control range from a credit of $80 to a cost
of $240 per Mg. Similarly, from Table 4-5, it can be seen that the cost
effectiveness of the median size model tank ranges from a credit of $135
for gasoline to a cost of $80 for crude oil per Mg of controlled emissions;
and from Table 4-6, the cost effectiveness of the large model tank varies
from a credit of $140 per Mg for gasoline to a cost of $35 per Mg for crude
oil emission control.
Figure 4-1 graphically depicts the estimated cost effectiveness curves
of controlling gasoline emissions and Figure 4-2 shows the similar curves
of controlling crude oil emissions. As would be expected, the curves show
that larger tanks are more cost effective than smaller tanks. Also, for each
tank size, the use of low values result in less favorable ratios and vice
versa. From Figure 4-1, it should be noted that the control of all tank
sizes should result in a savings (credit), except when low values apply
to tanks smaller than about 5,000 x 10 1. From Figure 4-2, it can be seen
that control of all tank sizes should result in a savings if high values
are appropriate or in a cost if low values pertain. But, if median values
apply, then control of tanks larger than about 2,000 x 10 1 should result
in a credit while control of smaller tanks should be a cost.
4-11
-------
Figure 4-1. Cost Effectiveness of Controlling Emissions From
Existing Fixed Koof baseline Tanks
200J_
I
ro
•o
0>
£
•M
O
U
in
c
O
CO
CO
0>
i-
OJ
O.
100--
A Low Turnover and TVP
£ (-IOO)-L
U
O
CJ
(-200)
Tank Product
Turn- TVP
Overs/yr kPa
A Low Values 5 13.8
B Median Values 10 41.4
C High Values 20 69.0
T
4000
8000
12,0*00 1MOO ": 20,f)G5" ~ 24,0^5"
Tank Size (103 1)
-------
300 __
Figure 4-2. Cost Effectiveness of Controlling Emissions
From Existing Fixed Roof Crude Oil Tanks
o
O
c
o
in
•^-
E
CO
200
100 J.
A Low Turnover & TVP
flJ
c.
-o
-------
4.4 REFERENCES
1. Gasoline and Crude Oil Emissions Before and After Control, calculated per AP-42,
Supplement No. 7.
2. "Refined-products prices", Oil and Gas Journal. October 17, 1977.
3. Monthly Energy Review. August, 1977, Office of Energy Information and
Analysis, National Energy Information Center. ,
4. Dr. W. Sheppard, Battelle Columbus Laboratories, Columbus, Ohio.
Petroleum liquids transportation cost data memo to file by R. A. Quaney,
U.S. Environmental Protection Agency, dated November .2, 1977.
5. R. C. Kern, Ultra-flote Corp., Houston, Texas. Internal floating roof
cost data memos to file by R. A. Quaney, U.S. Environmental Protection
Agency, dated November 7, 1977 and December 20, 1977.
6. Evaluation of Hydrocarbon Emissions From Petroleum Liquid Storage.
Pacific Environmental Services, Inc., Santa Monica, Cal,5 draft report
dated October, 1977.
7. K. J. Kolkmeier, Pittsburgh-Des Moines Steel Co., Pitt.,jurgn, Pa. Internal
floating roof cost data memos to file by R. A. Quaney, (J.S. Environmental
Protection Agency, dated November 9, 1977 and December 23, 1977.
8. Survey of Costs to Install Floating Roofs by Louisiana Division members
of Mid-Continent Oil and Gas Association, January 14, 1977.
4-14
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5.0 EFFECTS OF APPLYING THE TECHNOLOGY
The impacts on air pollution, water pollution, solid waste, and energy
are discussed in this chapter.
5.1 AIR POLLUTION IMPACTS
Estimated VOC emissions from fixed roof tanks (>150,000 liter capacity)
during 1976 are about 560 Mg/yr. This represents about 3 percent of total
nationwide VOC losses from stationary sources.
Emissions from these fixed roof tanks could be reduced to less than
56 Mg/yr by retrofitting fixed roof tanks with internal floating roofs.
Emissions from existing external floating roof tanks and internal floatin
roof tanks are estimated at 134 Mg/yr. This is '1 percent of the total estirrat
hydrocarbon emissions from stationary sources.
5.2 OTHER EFFECTS
EPA has examined the impacts of applying control techniques to the
storage of petroleum liquids and has determined that there are no
significant adverse effects on water pollution, solid waste, or energy.
5.3 REFERENCE
1. Evaluation of Hydrocarbon Emission from Petroleum Liquid Storage,
P r e 1 i mi n a ry Draft RePt, Pacific Environmental Service Inc.,
San.ta Monica, California, EPA Contract No. 68-02-2606, October, 1977.
5-1
-------
6.0 RECOMMENDED REGULATIONS, COMPLIANCE TEST METHOD
• • , .'AND RECORD KEEPING
The affected facilities are fixed roof storage tanks with capacities
greater than 150,000 liters containing petroleum liquids with a true vapor
pressure greater than 10.5 kPa.
6.1 RECOMMENDED REGULATIONS
Recommended regulations for the storage of petroleum liquids in
fixed roof tanks are:
1. All fixed roof tanks with capacities greater than 150,000 liters
storing volatile petroleum liquids (greater than 10.5 kPa TVP) should be
retrofitted as follows, except where exempted:
(a) Internal floating roofs equipped with a closure seal or seals, or
(b) alternative equivalent control.
2. There are to be no visible holes, tears, or other openings in
the seal or any seal fabric.
3. Where applicable:
All openings, except stub drains, are to be equipped with a cover,
seal or lid. The cover, seal or lid is to be in a closed position at all times
except when the device is in actual use. Automatic bleeder vents are to be
closed at all times except when the roof is floated off or landed on the roof
leg supports. Rim vents, if provided, are to be set to open when the roof is
• - ): •••'..
being floated off the roof leg supports or at the manufacturer's recommended
setting.
6-1
-------
4. Fixed roof tanks having capacities less than 1,600,000 liters used
to store produced crude oil and condensate prior to lease custody transfer
are exempted.
6.2 COMPLIANCE TEST METHOD
Determining compliance for fixed roof petroleum storage tanks equipped
with an internal floating roof should be by visual inspection of the floating
cover through the roof hatches. The cover should be uniformly floating
on or above the liquid and there should be no visible defects in the surface
of the cover or liquid accumulated on the cover. The seal must be intact
and uniformly in place around the circumference of the cover between the cover
and tank wall.
6.3 MONITORING AND RECORD KEEPING
It is recommended that routine inspections through the roof hatches
be conducted at six month or shorter intervals. Evidence of any type of
malfunction (as noted above) is to be recorded. Whenever the tank is
emptied for non-operational reasons such as maintenance, an emergency, or
other similar purposes (such as a Department of Transportation Inspection),
a complete inspection of the cover and seal is to be made and the condition
of the cover and seal recorded. The control agency should k? notified prior
to a complete inspection.
A record should be maintained of the average monthly storage temperature
and true vapor pressure of the petroleum liquid stored if the product has
a stored true vapor pressure greater than 7.0 kPa and is stored in u fixed
roof tank not equipped with an internal floating coyer or alternative equivalent
control device installed under 6.1.1.b above. The true vapor pressure may
be determined by using the average monthly storage temperdture and typical
6-2
-------
Reid vapor pressure of the stored product. Supporting analytical data can be
requested if there is a question on the values report for any product.
6-3
-------
TECHNICAL REPORT DATA
(Please read luilructions on the reverse before completing)
1. REPORT NO. 2.
EPA-450/2-77-036
4. TITLE AND SUBTITLE
Control of Volatile Organic Emissions From
Storage of Petroleum Liquids in Fixed Roof Tanks
7' AUT8?chsard K. Burr, ESED Robert Quaney, SASD
KerriC. Brothers, ESED
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, N.C. 27711
12. SPONSORING AGENCY NAME AND ADDRESS
Same as Box 9«
3 "PBZTBTfy 9 C
5. REPORT DATE
December, 1977
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
OAQPS 1.2-089
10. PROGRAM ELEMENT NO.
11, CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
! .
16. APSTRACT •
This re;ort provides the necessary guidance for development of regulations
limiting emissions of volatile organic compounds (VOC) from the storage of
petroleum liquids in fixed roof tanks. Reasonably available control technology
(RACT) is defined in this document; cost analysis for RACT is included for
evaluating the cost effectiveness of controlling fixed roof storage tank sources.
C
: ' ' . . . • -. • -. • ' ' ' ' • • • • "'•
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Air Pollution
Storage Tanks
Regulatory Guidance
I
{19. DISTRIBUTION STATEMENT
b.lDENTIFIERS/OPEN ENDED Tf RMS
Air pollution control
Stationary sources
Organic vapors
19. SECURITY CLASS (This Hvport)
Unclassified
20. SECUHI1 Y CLASS (This page)
Unclassified
c. COSATI 1 icIU/CJroup
21. NO. OF PAGES t
JHt ~L
2?. PRICE (
A(b3 , flcbl 1
EPA form 2220-1 (t-73)
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