STANDARD PRACTICE CONFIDENTIAL
Page
PREPARATION OF
PROCESS FLOW DIAGRAM
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JGS 210-120-1-12E
Rev.2
DATE
FEB.-28-'97
CONTENTS
PAGE
1. SCOPE.............................................................................................................................................................. 2
2. GENERAL........................................................................................................................................................ 2
2.1 Work Procedure......................................................................................................................................... 2
2.2 Purpose of PFD.......................................................................................................................................... 2
2.3 Format........................................................................................................................................................ 2
3. WORK PROCEDURE ..................................................................................................................................... 3
3.1 Preparatory Work ...................................................................................................................................... 3
3.2 Items to be Indicated ................................................................................................................................. 3
3.3 Stream Data ............................................................................................................................................... 3
4. GENERAL DRAFTING INSTRUCTIONS..................................................................................................... 4
4.1 Scale .......................................................................................................................................................... 4
4.2 Lines .......................................................................................................................................................... 4
4.2.1 Types ................................................................................................................................................. 4
4.2.2 Crossover........................................................................................................................................... 4
4.2.3 Denotation of Lines at Battery Limit Tie-in Points........................................................................... 5
4.2.4 Flow Direction................................................................................................................................... 5
5. INSTRUMENTATION .................................................................................................................................... 6
5.1 Instrument Symbols................................................................................................................................... 6
5.2 Functional Identification Letters of Instrument......................................................................................... 6
5.3 Cascade Control......................................................................................................................................... 6
5.4 Compound Control .................................................................................................................................... 6
6. EQUIPMENT SYMBOLS ............................................................................................................................... 7
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1. SCOPE
This standard practice covers the requirements of preparation procedure for the Process Flow Diagram (PFD)
for petroleum refineries, petrochemical, chemical plants and other related plants.
This standard practice covers the following two cases of PFD:
(1) JGC carries out the preparation of the PFD from draft to the As-Built PFD.
(2) JGC reviews, develops and revises the PFD prepared by the licensor, and prepares the As -Built PFD
finally.
2. GENERAL
2.1 Work Procedure
(1) Personnel concerned in preparatory work shall be designated prior to the commencement of PFD
preparation work and clarify the required basic items for the purpose of minimizing the revisions.
(2) The responsibility for the preparation, revision and handling of the PFD and relevant coordination shall in
principle be transferred from the process engineer to the project engineer upon issuance of the “PFD for
Construction”
(a) Up to issuance of the “PFD for Construction” : Process engineer
(b) Upon issuance thereof : Project engineer
2.2 Purpose of PFD
The purpose of PFD should be as follows:
(1) Scope of process
The identification of the scope of the plant to be constructed.
(2) Plant design basis
The identification of design basis indicating process flows from the feedstocks, to the products and byproducts.
(3) Equipment configuration
(4) Process Control Scheme
2.3 Format
(1) Form
JGC Standard form should be used, unless required by the Client.
(2) Drawing size
Basically ISO A1 size should be used.
However, ISO A2, A3 or X size can be used in accordance with the plant size.
(3) Flow direction
PFD should be drawn from left to right.
(4) Title block
The title block should include the following, unless required by the client.
- JGC logo
- Project name
- Unit name, if any
- Client’s name
- Drawing title
- Issue date
- Signature of prepared, checked and approved by the appropriate personnel
- JGC’s Job code
- Drawing number
- Revision number and reason for revision
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(5) Legend
The following should be indicated in legend.
- Operating pressure
- Operating temperature
- Heat duty for heat transfer equipment
3. WORK PROCEDURE
3.1 Preparatory Work
Prior to the preparation of PFD, heat and material balances including physical properties shall be calculated.
3.2 Items to be Indicated
The following shall be indicated on PFD.
(1) Equipment
- Shape
- Item number and service name
- Main dimensions or capacity
(2) Stream Lines
- Main process lines with stream number
- Secondary process lines, if important
- Main utility lines with related equipment
(3) Instrumentation
- Control system with control valves
- Important instruments
(4) Operating conditions around major equipment
(5) Stream data for main process lines (for details, reference is made to paragraph 3.3)
3.3 Stream Data
Stream data shall consist of the following:
(1) Stream number
(2) Stream description
(3) Molar or weight flow rate of individual components, if required
(4) Composition of flowing fluid, if required
(5) Total flow rate (Molar and Weight)
(6) Total volumetric flow rate, if required
(7) Molecular weight, if required
(8) Density, if required
(9) Liquid fraction
(10) Operating temperature
(11) Operating pressure
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4. GENERAL DRAFTING INSTRUCTIONS
4.1 Scale
PFD need not be drafted on scale. However, their shape should be compatible with that of equipment.
4.2 Lines
4.2.1 Types
The types of lines should be as follows :
(1) Main process lines
(2) Secondary process lines and utility lines
(3) Loop lines for instrumentation
4.2.2 Crossover
Where two lines cross each other, the horizontal line should basically take precedence over vertical ones.
(1) Where two main lines crossover
(2) Where one main line crosses one secondary line or utility line
(3) Where one main line, secondary lines or utility lines cross one loop line for an instrument:
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4.2.3 Denotation of Lines at Battery Limit Tie-in Points
(1) Process lines:
From Item No. and/or Drawing. No.
To Item No. and/or Drawing. No.
Where a PFD consists of two or more divided sheets, drawing numbers should be indicated.
(2) Utility lines:
Names of fluids should be given in parentheses above the utility lines.
Names of these fluids can be abbreviations defined for each job.
Cooling Water
Cooling Water
4.2.4 Flow Direction
The flow direction should be indicated by arrows. In principle all flow lines should be denoted by arrows
located at the inlet of equipment, merging points and the corners of the lines. Where a process line is long,
the process flow may be denoted by arrows located at intermediate points.
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5. INSTRUMENTATION
Instrumentation to be denoted includes measuring functions and control valves.
5.1 Instrument Symbols
(1) The symbol for an instrument is a circle which shall be connected to the nearest point of measurement on
the lines or equipment.
Note : an arrow shall be indicated if the
signal direction is not clear.
(2) Where the instrument has a controller, a dotted line representing the control impulse shall connect the
instrument circle to the controller valve.
5.2 Functional Identification Letters of Instrument
Functional identification letters of instrument shall be referred to JGS No. 210-120-1-70E “Drawing Standard
for P & I Diagram Preparation”.
Examples are shown below :
(1) FC : Flow Control
(2) PC : Pressure Control
(3) LAH : Level Alarm High
5.3 Cascade Control
Where one controller alters the set value of one or more other controllers, the circle instrument symbol shall be
connected by a dotted line.
LC
FC
5.4 Compound Control
Where the control actions of two or more controllers combine to operate one or more control valves, the
circles representing the instrument functions shall be joined by dotted lines to the circle representing the
combining device.
LC
FC
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6. EQUIPMENT SYMBOLS
The standard equipment symbols are shown below.
(1) Shell and tube heat exchanger
Coolant
Heating medium
Coolant
Heating medium
Tube side
Shell side
(a) Heat Exchanger
(b) Cooler
(c) Heater
(2) Reboiler
The direction of lines is optional, but the lines denoting the shell and tube sides respectively, should cross
each other at 90° or 45°.
Kettle Type
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(3) Air cooled heat exchanger
Where temperature controls must be selected in consideration of various factors, the process engineer will
show the control types on the PFD.
(a) No Automatic Control
(4) Plate type heat exchanger
(5) Double pipe heat exchanger
TC
TC
(b) Fan Pitch Control
(c) Louver Control
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(6) Furnace
All process streams connected to the furnace should be shown.
TC
Fuel
(7) Reactor
All process streams and catalyst beds should be shown.
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(8) Column
Important trays such as top, bottom, feed, side cut, reflux, etc. should be indicated.
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(a) Tray Column
(b) Packed Column
(9) Drum
(a) Horizontal
(b) Vertical
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(10) Pump
(a) Centrifugal Pump
(b) Reciprocating Pump
(11) Compressor, Expander and Blower
(a) Centrifugal Compressor
(b) Reciprocating Compressor
(c) Expander
(b) Blower
FC
SC
Compressor
Steam
Turbine
(e) Driver Control
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(12) Ejector
(13) Tank
(a) Cone Roof
(b) Dome Roof
(14) Typical Symbols for Operating Conditions
Temperature
Pressure
Flow Rate
Heat Duty
(c) Floating Roof
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(d) Sphere
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