The most effective way of communicating information about a process is through the use of flow diagr

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The most effective way of communicating
information about a process is through the use of
flow diagrams.
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Block Flow Diagrams (BFD)

• Emphasis not on details regarding the blocks
  rather, concentration on flow of streams through
  the process.
• Conventions
• Operations shown by blocks
• Major flow lines shown with arrows giving
  direction of flow
• Flow goes from left to right whenever possible
• Light streams toward top, heavy streams toward
  the bottom
• Critical information unique to the process
  supplied (i.e., reaction stoichiometry,
  conversion)
• Avoid crossing lines. When necessary, horizontal
  continuous, vertical broken.
• Simplified material balance (overall)

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create a block flow diagram
while high grade benzene can be
purchased, hydrogen purchased with N2 and CH4
impurity
hydrogen
cyclohexane
benzene
benzene
C6H6 3 H2 ?catalyst, ??C6H12
hydrogen
catalyst
conversion 99.8 C6H6
spent catalyst
nitrogen
reaction requires XS H2
nitrogen
methane
reaction is highly exothermic
methane
hydrogen 0.96/kg cyclohexane
2.25/gal benzene 2.18/gal
can we waste the XS hydrogen?
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create a block flow diagram
C6H6 3 H2 ?catalyst, ??C6H12
catalyst
hydrogen
nitrogen
hydrogen
methane
RXTR
SEP
benzene
cyclohexane
benzene
spent catalyst
The reactor effluent is cooled and the light
gases separated from the product stream. Part of
the light gas stream is fed back to the reactor
as recycle H2.
A portion of C6H12 product is recycled to the
reactor for temperature control.
conversion 99.8 C6H6
reaction requires XS H2
reaction is highly exothermic
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create a block flow diagram
C6H6 3 H2 ?catalyst, ??C6H12
catalyst
hydrogen
nitrogen
methane
hydrogen
RXTR
SEP
benzene
cyclohexane
spent catalyst
SEP
The liquid product stream from the separator is
fed to a distillation column to further remove
any dissolved light gases and to stabilize the
end product.
conversion 99.8 C6H6
reaction requires XS H2
benzene
reaction is highly exothermic
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create a block flow diagram
C6H6 3 H2 ?catalyst, ??C6H12
catalyst
hydrogen
nitrogen
hydrogen
methane
RXTR
SEP
cyclohexane
benzene
spent catalyst
SEP
Feed streams are preheated in a heat exchanger to
near reaction conditions.
conversion 99.8 C6H6
reaction requires XS H2
benzene
reaction is highly exothermic
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(No Transcript)
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cooling water in
hydrogen vent to flare
steam
cooling water out
process condensate to treatment
propylene cylinders
recycle toluene
propylene vent to flare
toluene tanker
T-200
K2CO3
steam
steam
steam
R-200/300
brine out
steam
brine in
TI
cw out
cw in
condensate
Na tank
condensate
R-100
s.c.
T-100
cooling water in
cooling water out
electric
steam
condensate
IBB product receiver
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Process Flow Diagram (PFD)

• contains most of the Chemical Engineering data
  necessary for design of a chemical process
• conventions
• Standards for content vary by the company
• All major equipment represented on a PFD, each
  uniquely numbered
• All process flow streams shown and uniquely
  numbered, with description of thermodynamic
  conditions and composition (often in an
  accompanying table)
• All utility streams supplied to major process
  equipment shown
• Basic control loops, illustrating control
  strategy during normal operation

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Process Flow Diagram (PFD)

• classification of basic PFD information
• Process Topology
• Stream Data
• Equipment Information

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Process Flow Diagram (PFD)

• Process Topology
• the location of and interaction between equipment
  and process streams
• Equipment identified by Icons representing a
  unit operation (no standard, but we will use that
  established by the text)
• Equipment numbering system XX-YZZ A/B
• XX equipment classification
• Y area located within plant
• ZZ equipment piece number designation
• A/B identifies parallel units (common with
  pumps)

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Process Flow Diagram (PFD)

• Stream Data
• May be included directly on diagram for small
  processes
• Included in an attached stream summary table for
  larger processes
• Information essential to the diagram includes
• Stream number
• Temperature
• Pressure
• Vapor fraction
• Total mass flow rate
• Total mole flow rate
• Individual component flow rates

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Process Flow Diagram (PFD)
Figure C.1 Process Flow Diagram for the
Production of Allyl Chloride (Reaction Section)
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Process Flow Diagram (PFD)
Figure C.1 Process Flow Diagram for the
Production of Allyl Chloride (Reaction Section)
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Process Flow Diagram (PFD)
Figure C.3 Separations Section of Allyl Chloride
Production Facility (Unit 600)
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Process Instrumentation Diagram (PID)

• support documents of the PFD used for planning
  for plant construction and maintaining the plant
  thereafter
• Each PFD requires many PIDs to provide the
  necessary data
• Used as a checklist at the final walk-through
  prior to start up to assure each detail has been
  attended to
• Use by/for
• MEs and CEs to build/install equipment
• Instrument engineers to specify/install/check
  control systems
• Piping engineers to develop plant layout and
  elevation drawings
• Project engineers to develop plant and
  construction schedules

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Process Instrumentation Diagram (PID)

• contains every mechanical aspect of the plant
  expect for
• Operating conditions
• Stream flows
• Equipment locations
• Pipe routing (lengths and fittings)
• Supports, structures, and foundations
• referred to as the Mechanical Flow Diagram
• Equipment Spare units, parallel units, detail
  summary of each unit
• Piping Size, schedule, MOC, insulation
  (thickness, type)
• instrumentation Indicators, recorders,
  controllers, instrument lines
• Utilities Entrance and exit utilities, exit to
  waste treatment facilities
• show where data is collected and/or recorded and
  how that information is handled

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The final control element in nearly all chemical
process control loops is a valve