Example Problem A - Batch Chemical Reactor, Engineering Chemical Engineering Notes | EduRev

 Page 1


Appendix
Worked
Examples
This appendix contains two example problems which are intended to illustrate
the use of the techniques and thought processes given in Chapters 2-12 of this
book. Each example will use specific process situations to show how to use
Chapter 2 to determine the process safety system (PSS) design basis, identify
the design parameters which have the strongest impact on that basis, and assist
in the selection of alternative inherently safer, passive, active and procedural
design solutions.
These examples are not intended to serve as a "standard" PSS design basis
for any industrial system. Each process and each design require specific
process information (such as equipment pressure and temperature ratings,
materials inventories, pipeline sizes, types of utility streams available, etc.)
which differ from manufacturer to manufacturer, and process to process. Also,
individual company policy and risk management procedures must provide
direction concerning safety systems design, especially concerning the applica-
bility of mitigation techniques. Any attempt to define an industry-wide "stan-
dard" is counterproductive, in that it may prevent the thoughtful analysis
required to define a safe, economical PSS system in favor of a "cookbook"
approach which would likely miss some significant potential hazards.
Page 2


Appendix
Worked
Examples
This appendix contains two example problems which are intended to illustrate
the use of the techniques and thought processes given in Chapters 2-12 of this
book. Each example will use specific process situations to show how to use
Chapter 2 to determine the process safety system (PSS) design basis, identify
the design parameters which have the strongest impact on that basis, and assist
in the selection of alternative inherently safer, passive, active and procedural
design solutions.
These examples are not intended to serve as a "standard" PSS design basis
for any industrial system. Each process and each design require specific
process information (such as equipment pressure and temperature ratings,
materials inventories, pipeline sizes, types of utility streams available, etc.)
which differ from manufacturer to manufacturer, and process to process. Also,
individual company policy and risk management procedures must provide
direction concerning safety systems design, especially concerning the applica-
bility of mitigation techniques. Any attempt to define an industry-wide "stan-
dard" is counterproductive, in that it may prevent the thoughtful analysis
required to define a safe, economical PSS system in favor of a "cookbook"
approach which would likely miss some significant potential hazards.
A
EXAMPLE PROBLEM:
BATCH CHEMICAL REACTOR
This example problem is based on an existing industrial batch reaction system.
It illustrates a batch reactor where a quinone-type organic compound is hydro-
genated to a hydroquinone. The reaction product is an intermediate for a
pharmaceutical.
Reactors require a detailed hazard analysis before the proper Process
Safety System (PSS) can be determined due to the complexity of the operation
(heat and mass transfer and chemical reaction), as well as the different kinds
and severity of events that can be caused by the reactants, products, catalysts,
and impurities.
For this example, two process drawings are presented:
• Exhibit Al: Process Flow Diagram (PFD) with a material balance and
equipment data.
• Exhibit A2: Piping & Instrumentation Diagram (PSdD).
Physical and hazardous properties were obtained from open technical lit-
erature and company files. The heat of reaction and runaway potential data
were obtained from adiabatic calorimeter tests.
A. I SYSTEM DESCRIPTION
The batch reactor and associated equipment are shown in Exhibit Al, along
with the material balance, and equipment data (sizes, dimensions, materials of
construction, etc.).
Page 3


Appendix
Worked
Examples
This appendix contains two example problems which are intended to illustrate
the use of the techniques and thought processes given in Chapters 2-12 of this
book. Each example will use specific process situations to show how to use
Chapter 2 to determine the process safety system (PSS) design basis, identify
the design parameters which have the strongest impact on that basis, and assist
in the selection of alternative inherently safer, passive, active and procedural
design solutions.
These examples are not intended to serve as a "standard" PSS design basis
for any industrial system. Each process and each design require specific
process information (such as equipment pressure and temperature ratings,
materials inventories, pipeline sizes, types of utility streams available, etc.)
which differ from manufacturer to manufacturer, and process to process. Also,
individual company policy and risk management procedures must provide
direction concerning safety systems design, especially concerning the applica-
bility of mitigation techniques. Any attempt to define an industry-wide "stan-
dard" is counterproductive, in that it may prevent the thoughtful analysis
required to define a safe, economical PSS system in favor of a "cookbook"
approach which would likely miss some significant potential hazards.
A
EXAMPLE PROBLEM:
BATCH CHEMICAL REACTOR
This example problem is based on an existing industrial batch reaction system.
It illustrates a batch reactor where a quinone-type organic compound is hydro-
genated to a hydroquinone. The reaction product is an intermediate for a
pharmaceutical.
Reactors require a detailed hazard analysis before the proper Process
Safety System (PSS) can be determined due to the complexity of the operation
(heat and mass transfer and chemical reaction), as well as the different kinds
and severity of events that can be caused by the reactants, products, catalysts,
and impurities.
For this example, two process drawings are presented:
• Exhibit Al: Process Flow Diagram (PFD) with a material balance and
equipment data.
• Exhibit A2: Piping & Instrumentation Diagram (PSdD).
Physical and hazardous properties were obtained from open technical lit-
erature and company files. The heat of reaction and runaway potential data
were obtained from adiabatic calorimeter tests.
A. I SYSTEM DESCRIPTION
The batch reactor and associated equipment are shown in Exhibit Al, along
with the material balance, and equipment data (sizes, dimensions, materials of
construction, etc.).
BRIhE
SUPPLY
BRINE
RETURN
NITROGEN
C.T. WATER
RETURN
LP.
STEAM
C.T.
WATER
SUPPLY
CONO.
TO BATCH
SURGE TANK
STREAM No.
STREAM NAME
COMPONENT
QUlNONE
SOLVENT A
SOLVENT B
Pd/C
WATER
IMPURITIES
HYDROGEN
TOTAL
TEMP.(-C) JPRES.(PSIG)
S.G.
VOLUME-GAL.
VOLUME-SCF
QUINONE-
SOLVENT A
SOLUTION
SOLVENTS
AZEOTROPIC
MIXTURE
CATALYST
SLURRY
SOLVENTS
AZEOMIXTURE
WASH FROM
CATALYST HEAD
TANK
HYDROGEN
EXHIBITAI
Process Flow Diagram (PFD) with a material balance and equipment data.
Page 4


Appendix
Worked
Examples
This appendix contains two example problems which are intended to illustrate
the use of the techniques and thought processes given in Chapters 2-12 of this
book. Each example will use specific process situations to show how to use
Chapter 2 to determine the process safety system (PSS) design basis, identify
the design parameters which have the strongest impact on that basis, and assist
in the selection of alternative inherently safer, passive, active and procedural
design solutions.
These examples are not intended to serve as a "standard" PSS design basis
for any industrial system. Each process and each design require specific
process information (such as equipment pressure and temperature ratings,
materials inventories, pipeline sizes, types of utility streams available, etc.)
which differ from manufacturer to manufacturer, and process to process. Also,
individual company policy and risk management procedures must provide
direction concerning safety systems design, especially concerning the applica-
bility of mitigation techniques. Any attempt to define an industry-wide "stan-
dard" is counterproductive, in that it may prevent the thoughtful analysis
required to define a safe, economical PSS system in favor of a "cookbook"
approach which would likely miss some significant potential hazards.
A
EXAMPLE PROBLEM:
BATCH CHEMICAL REACTOR
This example problem is based on an existing industrial batch reaction system.
It illustrates a batch reactor where a quinone-type organic compound is hydro-
genated to a hydroquinone. The reaction product is an intermediate for a
pharmaceutical.
Reactors require a detailed hazard analysis before the proper Process
Safety System (PSS) can be determined due to the complexity of the operation
(heat and mass transfer and chemical reaction), as well as the different kinds
and severity of events that can be caused by the reactants, products, catalysts,
and impurities.
For this example, two process drawings are presented:
• Exhibit Al: Process Flow Diagram (PFD) with a material balance and
equipment data.
• Exhibit A2: Piping & Instrumentation Diagram (PSdD).
Physical and hazardous properties were obtained from open technical lit-
erature and company files. The heat of reaction and runaway potential data
were obtained from adiabatic calorimeter tests.
A. I SYSTEM DESCRIPTION
The batch reactor and associated equipment are shown in Exhibit Al, along
with the material balance, and equipment data (sizes, dimensions, materials of
construction, etc.).
BRIhE
SUPPLY
BRINE
RETURN
NITROGEN
C.T. WATER
RETURN
LP.
STEAM
C.T.
WATER
SUPPLY
CONO.
TO BATCH
SURGE TANK
STREAM No.
STREAM NAME
COMPONENT
QUlNONE
SOLVENT A
SOLVENT B
Pd/C
WATER
IMPURITIES
HYDROGEN
TOTAL
TEMP.(-C) JPRES.(PSIG)
S.G.
VOLUME-GAL.
VOLUME-SCF
QUINONE-
SOLVENT A
SOLUTION
SOLVENTS
AZEOTROPIC
MIXTURE
CATALYST
SLURRY
SOLVENTS
AZEOMIXTURE
WASH FROM
CATALYST HEAD
TANK
HYDROGEN
EXHIBITAI
Process Flow Diagram (PFD) with a material balance and equipment data.
100 PSIG
NITROGEN HEADER
TO ORTHOTANK ON ROOF
TO VgNT HEADER CHILLER
CATALYST SLURRY
FROM HEAD TANK
OUINONE
SOLVENTS
AZEO MIXTURE
FROM SURGE
TANK
SOLVENTS
AZEO MIXTURE
WASH FROM
CATALYST HEAD
TANK
!M
1
W
FLUID RESERVOIR
HYDROGEN SUPPLY
Rftgg--^
DETAIL V
SYMBOLS
FELO INSTKUkCNT
LOCAL PANEL INSTRUMENT
PROTECTIVE PIPE COVER (WEATHER CAP)
ROOF
VENT LME
NOTES:
1. BURST DISK DETECTOR
2. LOCATE H2 DETECTOR
HEAD AS CLOSE AS
POSSIBLE TO AND
IMMEDIATELY ABOVE
THE AGITATOR SEAL.
EXHIBIT A2
PIPING AND INSTRUMENTATION DIAGRAM
M- 1 MECH SEAL
FLUID RESERVOIR
TO AGITATOR
MECH. SEAL
DETAIL "A"
TO ISOLATION
VALVE IN H2
LINE TO R-1
C.T. WATER
RETURN
8%R
HMB
1
*-
CONDENSATE
RETURN HEADER
R-1
4 BAFFLES
FuiWU
LP. STEAM
Page 5


Appendix
Worked
Examples
This appendix contains two example problems which are intended to illustrate
the use of the techniques and thought processes given in Chapters 2-12 of this
book. Each example will use specific process situations to show how to use
Chapter 2 to determine the process safety system (PSS) design basis, identify
the design parameters which have the strongest impact on that basis, and assist
in the selection of alternative inherently safer, passive, active and procedural
design solutions.
These examples are not intended to serve as a "standard" PSS design basis
for any industrial system. Each process and each design require specific
process information (such as equipment pressure and temperature ratings,
materials inventories, pipeline sizes, types of utility streams available, etc.)
which differ from manufacturer to manufacturer, and process to process. Also,
individual company policy and risk management procedures must provide
direction concerning safety systems design, especially concerning the applica-
bility of mitigation techniques. Any attempt to define an industry-wide "stan-
dard" is counterproductive, in that it may prevent the thoughtful analysis
required to define a safe, economical PSS system in favor of a "cookbook"
approach which would likely miss some significant potential hazards.
A
EXAMPLE PROBLEM:
BATCH CHEMICAL REACTOR
This example problem is based on an existing industrial batch reaction system.
It illustrates a batch reactor where a quinone-type organic compound is hydro-
genated to a hydroquinone. The reaction product is an intermediate for a
pharmaceutical.
Reactors require a detailed hazard analysis before the proper Process
Safety System (PSS) can be determined due to the complexity of the operation
(heat and mass transfer and chemical reaction), as well as the different kinds
and severity of events that can be caused by the reactants, products, catalysts,
and impurities.
For this example, two process drawings are presented:
• Exhibit Al: Process Flow Diagram (PFD) with a material balance and
equipment data.
• Exhibit A2: Piping & Instrumentation Diagram (PSdD).
Physical and hazardous properties were obtained from open technical lit-
erature and company files. The heat of reaction and runaway potential data
were obtained from adiabatic calorimeter tests.
A. I SYSTEM DESCRIPTION
The batch reactor and associated equipment are shown in Exhibit Al, along
with the material balance, and equipment data (sizes, dimensions, materials of
construction, etc.).
BRIhE
SUPPLY
BRINE
RETURN
NITROGEN
C.T. WATER
RETURN
LP.
STEAM
C.T.
WATER
SUPPLY
CONO.
TO BATCH
SURGE TANK
STREAM No.
STREAM NAME
COMPONENT
QUlNONE
SOLVENT A
SOLVENT B
Pd/C
WATER
IMPURITIES
HYDROGEN
TOTAL
TEMP.(-C) JPRES.(PSIG)
S.G.
VOLUME-GAL.
VOLUME-SCF
QUINONE-
SOLVENT A
SOLUTION
SOLVENTS
AZEOTROPIC
MIXTURE
CATALYST
SLURRY
SOLVENTS
AZEOMIXTURE
WASH FROM
CATALYST HEAD
TANK
HYDROGEN
EXHIBITAI
Process Flow Diagram (PFD) with a material balance and equipment data.
100 PSIG
NITROGEN HEADER
TO ORTHOTANK ON ROOF
TO VgNT HEADER CHILLER
CATALYST SLURRY
FROM HEAD TANK
OUINONE
SOLVENTS
AZEO MIXTURE
FROM SURGE
TANK
SOLVENTS
AZEO MIXTURE
WASH FROM
CATALYST HEAD
TANK
!M
1
W
FLUID RESERVOIR
HYDROGEN SUPPLY
Rftgg--^
DETAIL V
SYMBOLS
FELO INSTKUkCNT
LOCAL PANEL INSTRUMENT
PROTECTIVE PIPE COVER (WEATHER CAP)
ROOF
VENT LME
NOTES:
1. BURST DISK DETECTOR
2. LOCATE H2 DETECTOR
HEAD AS CLOSE AS
POSSIBLE TO AND
IMMEDIATELY ABOVE
THE AGITATOR SEAL.
EXHIBIT A2
PIPING AND INSTRUMENTATION DIAGRAM
M- 1 MECH SEAL
FLUID RESERVOIR
TO AGITATOR
MECH. SEAL
DETAIL "A"
TO ISOLATION
VALVE IN H2
LINE TO R-1
C.T. WATER
RETURN
8%R
HMB
1
*-
CONDENSATE
RETURN HEADER
R-1
4 BAFFLES
FuiWU
LP. STEAM
The operational sequence is as follows:
1. The reactor is charged with a solution of the quinone in solvent A.
2. The reactor is charged with an azeotropic mixture of solvent A and
solvent B.
3. The reactor mixture is heated to 50-55
0
C.
4. The reactor is pressure purged three times with 15 psig nitrogen to
displace the air.
5. The reactor is charged with the palladium on carbon catalyst slurried in
the solvent A / solvent B azeotropic mixture.
6. The catalyst slurry head tank is washed with azeotropic mixture of
solvent A and solvent B into the reactor.
7. The reactor is pressure purged three times with 10 psig hydrogen to
displace the nitrogen.
8. The reactor jacket is switched from heating to cooling service.
9. The reactor hydrogen pressure is raised to 15 psig and the hydrogena-
tion is continued until the hydrogen uptake stops (about 2
l
/2 hours).
10. The reactor hydrogen pressure is raised to 20 psig, the hydrogen is
isolated, and the reactor pressure is held for 20 minutes.
11. The reactor is vented down to about 1 psig.
12. The reactor is pressure purged three times with 15 psig nitrogen to
displace the hydrogen.
13. The reactor jacket is switched from cooling to heating service.
14. The reactor mixture is heated to 60-7O
0
C.
15. The reaction mass is transferred with 5 psig nitrogen pressure to a
surge tank. This leaves the reactor incited for the next batch.
Selection of the design basis for this example will follow the nine-step
process explained in Chapter 2. In order to adequately perform Step 1—Iden-
tify Failure Scenarios, some discussion of information requirements in gen-
eral, and batch reactor systems in particular, is warranted, along with specific
information pertaining to this process.
A.2 GENERAL INFORMATION REQUIREMENTS
The following information will be required to properly evaluate potential fail-
ure scenarios:
• Heat and material balance (HMB) data
• Material Safety Data Sheets (MSDSs) for all chemicals
• Pure component and mixture physical property data (e.g., electrical
conductivity, viscosity, etc.)