Draft
8 ENFORCEMENT WORKSHOP ON
I PLANT INSPECTION AND
I EVALUATION
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U
c VOLUME
111 PROCESS AND CONTROL EQUIPMENT
i FLOW CHARTING TECHNIQUES
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U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
•g OFFICE OF GENERAL ENFORCEMENT
WASHINGTON, D.C. 20460
/A/OAS
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ENFORCEMENT WORKSHOP ON
PLANT INSPECTION AND EVALUATION
Volume III
Process and Control Equipment
Flow Charting Techniques
Prepared by
John R. Richards
PEDCo Environmental, Inc.
505 S. Duke Street
Durham, North Carolina 27701
Contract No. 68-01-4147
P/N 3470-3-B
Prepared for
U. S. ENVIRONMENTAL PROTECTION AGENCY
Division of Stationary Source Enforcement
Office of Enforcement
Washington, D.C. 20460
February 1979
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FLOWCHARTING TECHNIQUE FOR FIELD INSPECTIONS
A flowchart, by definition, shows the flow of materials
through a process. The charts twofold purpose is to sim-
plify a complicated process and to improve communications
among people who design, maintain, or operate the process
equipment. These people are usually industrial personnel or
process engineers. However, the installation of control
equipment to reduce emissions from process equipment has
created a new group of users—the field inspectors.
The following types of flowcharts are typical of those
used by engineers:
Process control instrumentation Piping design
Material balance Utility Supply Systems
Electrical system design Process block diagrams
Two of these types, the process block and the process con-
trol instrumentation, have information on plant utilities
and material balances that is needed by inspectors for
routine evaluation of control equipment performance. With
this information, the inspector identifies:
Control equipment type Emission points
Series or parallel layout Operating conditions
The typical flowcharts posted on control room monitoring
panels too often include too much detail on the process and
not enough on the controls.
This handout is a guide for creating flowcharts that
represent control systems. It is designed to lead you
through a step-by-step preparation using many well known and
some newly designed sysmbols and notations for:
Effluent gas streams Plant Utility streams
Emission points Process and control equipment
Material streams Instrumentation
The explanations and examples used to present this approach
to a flowcharting technique become increasingly involved as
the steps in the preparation proceed from the basic lines
and to the additions of symbols that represent flows, emis-
sions, equipment, and so forth that make up the complete
flowchart.
1.0 FLOW LINES AND EMISSION POINTS
Four line widths (Example 1) are used in the flowchart
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technique developed herein. Each represents a separate part
of a process, as shown by the labels on the lines in the
example.
INDICATOR LINES
PLANT UTILITY STREAMS ^
PROCESS MATERIAL STREAMS
EFFLUENT GAS STREAMS ^
t
1
2
. 3
. 4
Example 1
The arrow on the ends of the lines indicate either the
location of equipment (line 1) or the direction of flow of a
stream (lines 2, 3, and 4)
The triangle-shaped label (example 2) is a notation
that differentiates between types of sources: the CE de-
notes contained effluent and the FE denotes fugitive ef-
fluent. The number in the triangle identifies the emission
point; this number is assigned from left to right in the
process flow by the inspector.
Example 2
The widest, most eyecatching line (#4), was chosen for
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the contaminated effluent gas stream because it is generally
the stream of primary interest to inspectors.
The medium line (#3) represents major material streams
in the process; inclusion of all would overcrowd and com-
plicate the chart unnecessarily. In a power plant, this
major stream would be the flow of coal feed to the boiler;
in te Kraft pulp mill, it would be the black liquor, di-
gested pulp, and several others. In Example 3, the raw
materials flow through the drier into the clinker.
Rotary Drier
Raw Materials
Natural Gas
Clinker .
Example 3
The fine lines (#1 and #2) may point to equipment such
as a rotary drier or to the flow of a substance such as
natural gas (Example 3). The inverted-S indicates that the
natural gas flow system is not shown.
The last pages of this handout (pp. 15-22) are pic-
torial representations of process equipment, control equip-
ment, accessories, and pipes and flow lines. Each pictorial
symbol has lines of varying width for effluent gas, major
material, and plant utility streams, as appropriate. Most
of these symbols are in common use.l'^ Others have been
created for this handout. Still others may need to be
developed by inspectors to communicate basic information on
control system designs and operating characteristics. So,
empty blocks are provided on the last pages for adding more
symbols.
2.0 PLANT UTILITIES
In most processes, there are many plant utility streams
which could be represented if one wished to completely
describe the system. Most of these are of only incidental
interest. We have chosen a set of notations from the many
in common use to indicate the presence of streams. These
are listed below:
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A - Plant Air
B - Brine
BW - Boilerfeed Water
C - Catalyst
CW - Cooling Water
Utility Streams
DW - Distilled Water HM
FG - Fuel Gas HS
FO - Fuel Oil LS
FC - Fuel Coal* PW
FW - Fuel Wood (Hogged SC
Scrap)*
Heating Medium
High Pressure Steam
Low Pressure Steam
Potable Water
Steam Condensate
The notations with an asterisk are new and thus are not now
in common use; these were added because we are not aware of
any being used consistently for coal and wood.
Example 4 shows two plant utility streams—the LS
flowing to the carbon adsorption bed and the CW flowing to
the indirect heat exchanger. The "A" notation represents
motor-operated valves (box 59, page 21) for regulating air
flow in the plant. Example 4 also shows how to add control
and process equipment to a flowchart. The symbols for the
adsorber (boxes 35 and 43, pages 18 and 19) the exchanger
(box 10, page 15) and the flow lines to each are drawn with
#2 lines. The circle with the dark center shows the exit
point of the air flow line (top of Example 4) from the rest
of the process which is not shown in the figure.
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3.0 PROCESS AND CONTROL EQUIPMENT
Symbols for fabric filter bags represent the cleaning
techniques and the flow pattern of contaminated gas through
the filters. For example, the reverse air filter (box 31)
shows that the particulate laden gas goes through the out-
side of the bag and exits through a plenum chamber at the
top of the bag assembly. The cleaning technique is a reverse
airflow supplied by an independent fan (box 62) which pulls
in ambient air. The symbol for the pulse jet fabric filter
(box 33) is similar, but it has venturi (box 48) above each.
Multicompartment fabric filters (box 30) are illustrated by
a large rectangle partitioned into smaller rectangular
compartments. Only one bag is shown to reduce the time and
space required to draw the symbol; however, in the space to
the left of the large rectangle, the field inspector may
indicate the number of bags and the bag material.
Because the most important characteristics of electro-
static precipitators (ESP's) is the number and arrangement
of transformer-rectifier (TR) sets, the symbol is a top view
of an ESP showing the arrangement of TR sets (boxes 28 and
29, page 18). It is particularly important to clearly
indicate the plant numbering system for each TR set; this
information ties the various monitoring instruments to the
ESP layout on which the diagnosis of ESP performance de-
pends. In the extra space in the ESP symbol, the field
inspector may wish to indicate the SCA or other parameters
of interest.
The process and control system symbols in Example 5
represent a typical coal-fired boiler of 500-megawatt gen-
erating capacity. In this case, the ESP has six separately
energized sections, each section supplied by a TR set; the
inlet fields are 1A and IB; there are two parallel layouts
with three TR sets in each. The boiler symbol includes a
block labelled APH, which simply means that the effluent
passes through the air preheater (APH) before entering the
ESP and that the ESP is a cold-side unit. In recent in-
stallations in which low sulfur coal is being burned, the
utility has installed the ESP between the boiler and the air
preheater. This type is termed a hot-side ESP and has
significantly different operating characteristics than the
more conventional cold-side type.
In some cases, it may be desirable to put some of the
process/control system operating data in rectangular boxes
or in tables on the flowchart to facilitate comparisons of
observed conditions with those typical of the installation.
The boxes and the tabular form are illustrated in Examples 6
and 7.
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FC
Boiler
500 MW
CE
Bottoms
Ash
]
1A
IB
i
2SP
2A
2E
i
3A
3B
Ash
Example 5
Temp - 125°F
Flow-20,000 ACFM
Temp-700"F
GR/dSCF-1.0
FI ntj-^ s nnn AP.FM
GR/dSCF-1.0
Flow-23,000 ACFM
Temp 200°F
GR/dSCF 0.05
Example 6
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Stream
1
2
3
4
Temp, °F
700
400
125
200
gr/dSCF
1.0
1.0
OA
0.1
Flow, ACFM
35,000
26,000
17,700
20,000
Comments
Example 7
4.0 INSTRUMENTATION
The delegation of enforcement authority to the States
with respect to Standards of Performance for New Sources
(NSPS) means that more instruments will be encountered by
the field inspectors. Inspection of continuous monitors and
use of the CM data for performance diagnoses will become
integral parts of the seure© inspection rout.tno tor major
point sources; thus flowchart symbols were e'lt
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Notations for the process and control equipment in-
strumentation has been taken primarily from the Instrument
Society of America (ISA).^'^ We have made changes and
additions to update the terminology.
The presence of an instrument is symbolized by a circle
(e.g., PI in Example 8) and a line pointing to the general
location in the system. The type of instrument is identi-
fied by the notations listed below. Please note the two
classes of notations: those ending in R and those ending in
I. The letter "I" specifies that the instrument is an
indicator only, while the letter "R" states that it is
equipped with a recorder (stripchart, maganetic tape, etc.).
Instrument Notations
FI - Flow Indicator
FR - Flow Recorder
LG - Gage Glass
LCI - Level Control Indicator
PCI - Pressure Control Indicator
PR - Pressure Recorder
TI - Temperature Recorder Indicator
DPI - Differential Pressure Indicator
DPR - Differential Pressure Recorder
PWI - Power Indicator
CMI - Continuous Monitor Indicator
CMR - Continuous Monitor Recorder
V - Voltage
A - Current (AC)
PV - Primary Voltage
PA - Primary Current (AC)
SC - Secondary Current (DC)
SPK - Spark Rate
It is generally not necessary to identify the type; however,
this may be done within the circle, as shown in Example 8.
0
0 - 10"
Example 8
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The use of a line across the diameter of the circle
demonstrates that the instrument panel is probably located
in a substation (SS) or a control room (CR). (This is not
standard ISA notation.) The location can be specified by
adding SS or CR to the bottom half of the circle as illustrated
in Example 9.
9-A 9-B 9-C
Example 9
The symbol for 9-A means that a temperature-indicating
monitor is mounted in the vicinity of the control device.
The horizontal line of 9-B states that the monitor is on a
control panel. The 9-C with its CR shows that the tem-
perature can be checked in the main control room.
The distinction which should be made is whether the
continuous monitor is in-situ or extractive. The latter
extracts a small sample stream from the breeching or stack,
but the former is mounted inside of the stack. The in-situ
monitor is subjected to substances in the exhaust ducts and
thus requires regular cleaning and maintenance of the pro-
tective blowers. The extractive monitor is free of the
stack problems, but experiences some sample deterioration
and probe corrosion. In-situ monitors are denoted by a
long, narrow rectangle spanning the stack or exhaust duct;
the extractive monitors are identified by a square and a
distinct sampling line. Both monitors are illustrated in
Example 10. The symbol CMR denotes a continuous monitor re-
corder. The substance being measured (e.g., SO?) identified
in the rectangle; other possibilities include NOx/ °2/ TRS,
Opacity. The 10-A states that an SC-2 in-situ monitor is
mounted in the stack with power and continuous monitor
indicators (PMI and CMI) located in the control room (CR).
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The 10-B also illustrates an in-situ monitor; however, it is
in the exhaust ducts. The #4 in 10-B shows that there are
four parallel ducts, each with an opacity montitor. The
10-C indicates an extractive monitor with the sampling probe
located in the stack; there is no information on the loca-
tion of the instruments. Similar to 10-B is 10-D except
that an extractive monitor is indicated.
10-A
10-B
10-C
10-D
Example 10
5.0 MATERIAL OF CONSTRUCTION
Some of the main causes of control system failures are
corrosion and erosion. If these problems are likely, it may
be helpful to indicate the materials of construction on the
floweharfe to rewind the field inspector of potential pro-
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blems or process changes that could cause rapid equipment
deterioration. We suggest a three-part code identifying the
material thickness, the basic material of construction, and
the coatings or liners present. The thickness and the
coatings/liners need not be coded unless they are deemed
important. For the basic material, the symbols or words
listed below are suggested.
Symbol Material
SS Stainless Steel
FRP Fiberglass Reinforced Plastic
CS Carbon Steel
Hastalloy Hastalloy
Inconel Inconel
Aluminum Aluminum
Titanium Titanium
Wood Wood
We have chosen not to abbreviate the material name as this
could lead to confusion. The user may select any codes that
are appropriate.
A three-part code of thickness, the basic material, and
surface protection for 1/4" thick stainless steel with a
rubber liner would be denoted as l/4-SS304-rubber. A #1
indicator line should be used to connect the code with the
equipment as illustrated in Example 11.
CW
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Example 11 illustrates a venturi scrubber (boxes 48 and
50, page 19) used for the control of SC>2 from a combustion
source. The venturi itself is made of 1/2" thick 316L
stainless steel, and the cyclonic separator is composed of
3/8" thick carbon steel with an epoxy coating. There are
temperature and flow indicators (TI and FI) mounted in the
general vicinity of the control equipment. A continuous
extractive monitor type with a probe in the main stack is
used for the measurement of S02/ and the output of the
monitor is located in the control room (CR). The ID fan
power indicator light is in the main control room; however,
the current (A) is monitored by a panel meter mounted on the
plant gounds.
6.0 EXAMPLE OF A COMPLETE FLOWCHART
A complete flowchart for a coal-fired utility boiler is
shown in Example 12. This is a combination and extension of
Examples 5 and 10. Most of the important components of a
flowchart are included in this example.
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Example 12,
Coal-Fired Utility Boiler
Controlled by a "Cold-Side"
Electrostatic Precipitator
Each T-R Set
—
.CR
SCA = 400
1-B 1-C
2-B
1 ;. ,-.
Each' Hop'pef
2-C
Temp = 275°F
Flow = 150,000 ACFM
gr/dSF =0.5
Flyash
M
n
(U
4J
(0
(V
(A
^
o
CO
M
O
>i
(1)
c
o
o
Temp =270°
Flow = 150,000 ACFM
gr/dSCF =0.05
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REFERENCES
1. Hill, R.G. Drawing Effective Flowsheet Symbols. Chemical
Engineering, January 1,1968, Pages 84-92.
2. O'Donnell, J.P. How Flowsheets Communicate Engineering
Information. Chemical Engineering Report,September 1957,
Pages 249-266.
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ue.
Rotary Drier
/ \
Furnace
Fue
Ball Mill
Screen
Bucket Conveyo:
Ribbon
Blender
Drum,
Horizontal
8
10
11
Pug Mill
1 I
Bagger
CW
Indirect
Heat Exchange
V
Bin
12
r*
14
15
Flare
Flare w/Steam
Reactor with
Agitator
Prilling Towei
PROCESS EQUIPMENT
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16-NEW
o_
CL
JJ
Conveyor, Transfer Point
17-NEW
Truck/Rail Unloading Hopper
18-NEW
19
Boiler
'CE
Hopper
20-NEW
21-NEW
Multiple Effect
Evaporators
Storage Pile
22-NEW
23-NEW
o o o u
Tenter Frame
Curing Oven
PROCESS EQUIPMENT
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2 4 -MEW
Sander
2 5 -NEW
Cotton Gin
26-NEW
\\\\\
\\\
H2SC>4 Absorber
2 7 -NEW
A
onical Burner
PROCESS EQUIPMENT
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-NEW
Electrostatic Precipitator
O
Positive Corona
Electrostatic Precipitator
30-NEW
31-NEW
Multicompartment
Reverse Air Fabric Filter
Reverse-Air
Fabric Filter
32-NEW
33-NEW
Multicompartment
Shaker Fabric Filter
Pulse Jet
Fabric Filter
,3,4-NEW
35
Panel Filter
Adsorber
AIR POLLUTION CONTROL EQUIPMENT
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36
Brinks Demister
Mesh Demister
crubber,
BubBle tray
38
39
Absorber
40-NEW
Oo
Turbulent
Contact
41
42
43
I//////
Spray Chamber
Jcrubber,
Impingment
Chevron Demist*
44
Stack
45
46
47-NEW
settling Chamber Cyclone
Multilone
48-NEW
\
i
AE
Venturi
49-NEW
50-NEW
&E
Venturi,
\d-justable
Venturi with Cyclonic
Separator
AIR POLLUTION CONTROL EQUIPMENT
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51
Rotary Vacuum Filter
52
T
WE
Filter Press
53
54
0
\
Pond
Activated Sludge Basin
55
56
Clarifier
Trickling Bed
WATER AND WASTEWATER
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57
I
Rotary Valve
58
t" A. A A /\ I
V V V \|
Screw Conveyor
59
Air-Motor-
Operated Valve
60
Electric-Motor
Operated Valve
61
62
63
Damper Valve
Fan
Pump
ACCESSORIES
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64
"\-\
Steam
Pipe,
Steam Traced
65
HD-
In-Line Filter
66
Separator,
Oil, Water
67
Pipe,
Jacketed
FLOW LINES AND PIPING
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