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Design of a High Production Volume Benzyl Chloride Manufacturing Plant
CSChE Conference 2014
UNIVERSITY OF OTTAWA DEPARTMENT OF CHEMICAL AND BIOLOGICAL ENGINEERING
FOR SNC LAVALIN PLANT DESIGN COMPETITION
Ryan Bekeris Martin Dussault Matthew Hudder Robert Tyssen
Acknowledgements
• Special thanks is given to Dr. Jules Thibault and Joanne GamageMcEvoy, of the University of Ottawa Department of Chemical and Biological Engineering, for their assistance, advice, and support over the course of this project.
• Additional thanks to all members of the uOttawa Department of Chemical and Biological Engineering for their unmatched professionalism, for challenging us, and for providing us with the tools and expertise necessary to succeed as engineers.
2
Project Objectives
• Design a high production volume benzyl chloride manufacturing plant
• Minimize capital and operating costs, and maximize profitability and process feasibility
• Emphasis on a safe, highly selective, and energy efficient process
3
Presentation Outline
1. Introduction
2. Process description
3. Economics
4. Process optimization
5. Safety considerations
6. Project summary and conclusions
4
INTRODUCTION
5
Introduction > Benzyl Chloride
• Colourless liquid with a pungent odour
ρ = 1.10 g/cm MM = 126.58 g/mol
Tb = 179°C
• Primarily used as a starting material for other syntheses
• Benzyl alcohol (solvent; ester precursor)
• Butyl benzyl phthalate (PVC plasticizer)
• Quaternary ammonium salts
• Phenylacetic acid
6
Introduction > Market Growth and Demand
• Global demand of 400,000 metric tonnes per year
• Global consumption growth of 4% per year
• Increased North American imports from Europe/Asia
7
Introduction > Facility Location
• Positioned near Co-op Refinery Complex
• Toluene supply, consumer market, industrialized location
8
$250k for 10 acres of undeveloped land
Introduction > Market Projections
• Toluene global price index:
9
Introduction > Market Projections
• Peak in toluene prices – correlated to crude oil and naphtha prices
• Decline in toluene price predicted over several months
• Gross material profit increase of 44%
• Economic analysis performed using peak toluene prices
10
Introduction > Reaction pathway
• Photo-chlorination of toluene
• Most economical pathway, with highest yield and selectivity, and least hazardous materials
11
Benzyl Chloride
Main product can further chlorinate to produce unwanted benzal chloride (left), and benzotrichloride (right)
Introduction > Hazards
• Many chemicals in the process are hazardous
• High emphasis on process safety and control
• Consideration for materials of construction• Hastelloy® B nickel alloy provides high corrosion resistance
12
Toluene Chlorine HCl Bn. Clx (x = 1, 2, 3)
Flammable YES YES
Explosive YES YES
Corrosive YES YES YES
Irritant YES YES YES YES
Poisonous YES YES YES YES
PROCESS DESCRIPTION AND PLANT LAYOUT
13
Process Description > Overall Process
14
Toluene
Feed Preparation
ReactorsLight Ends
Removal via Distillation
Product Purification
via Distillation
Toluene Removal via
Flash
HCl Removal via
Absorption
Chlorine Recylce
Toluene Recycle
HCl (aq) 36 wt%
Benzyl Chloride
Organic Wastes
Chlorine
Acid Feedwater
Stream Mass Flow
Toluene Feed 77.5 kt/year
Chlorine Feed 62.0 kt/year
Acid Feedwater 61.2 kt/year
Benzyl Chloride Product 96.2 kt/year
HCl (aq) Product 93.1 kt/year
Organic Wastes 11.4 kt/year* Mass balance assumes operation 50 weeks per year
Process Description > Overall Process
15
R-100 R-101 R-102 R-103
E-100
E-101
T-100
C-101C-100
P-100 A/B
K-100 A/B
T-100 Cond.
T-100 Reboil.T-101
T-101 Cond.
T-101 Reboil.
E-102 E-103 V-105
E-104 E-105
E-106 E-107
E-108
P-101 A/B
LPS
LPS
RW
CW RW
CW RW
CW
HPS
CW
HPS
CW RF
Toluene
Chlorine
Benzyl Chloride
Organic Waste
Water
HCl (aq)
Process Description > Feed Preparation
16
E-100
E-101
TolueneFeed
P-101 A/B
TolueneRecycle
LPS
LPS
ChlorineRecycle
ChlorineFeed
1 2
4 5
3
6
7
8
9
To Reactor
To Reactor
Process Description > Reactors
• Approximately 30% single-pass conversion of toluene
• Overall benzyl chloride yield is approximately 94%
17
R-100 R-101 R-102 R-103 P-101 A/B
K-100 A/B
PreparedChlorine
PreparedToluene
ProductPurification
1
2
3
4
5
6
7
Process Description > Reactors
Bubble column reactor
18
hliq = D = 1.4 m εgas = 0.3
4 identical reactors
Process Description > Separation
19
T-100
C-101C-100
T-100 Cond.
T-100 Reboil.T-101
T-101 Cond.
T-101 Reboil.
E-102 E-103 V-105
E-104 E-105
E-106 E-107
E-108
RW
CW RW
CW RW
CW
HPS
CW
HPS
CW RF
From Reactor
Toluene to Recycle
Benzyl Chloride
Organic Wastes
Chlorine to Recycle
HCl (aq) 36 wt%
Acid Feedwater
Process Description > Separation
Falling Film
Absorption
20
Δhabs ≈ 75 kJ/kmol @ 25°C
Tb = 58°C for 36 wt% HCl acid
Process Description > Plant Layout
21
R-102R-101 R-103R-100
K-100
T-100T-101
V-105
C-100
C-101
P-100P-101
V-104
V-102
V-100
V-101
Office SpaceCafeteria
Shipping and Receiving
Laboratory
Parking Lot
V-103
V-106
Machine Shop
Warehouse
V-101
V-101
V-101
V-101
V-101
V-101
Reagent Loading Location
Product Loading Location
Pip
e R
ack
Pipe Rack
Pip
e R
ack
E-100
E-101
E-102 + E-103
T-100 Condenser
T-100 Reboile
r
T-101 Condense
r
T-101 Reboiler
E-104 + E-105
E-106 + E-107
E-108
Overhead Piping
Vehicle Loading
Zone
Control Room
ECONOMIC ANALYSIS
22
Economic Analysis > Capital Expenses (CAPEX)
Capital Expenses – $96.6 million USD + $250k for land
23
Storage Tanks (30 day capacity)
83%
Heat Exchangers2%
Absorption Columns
2%
Distillation Columns
7%
Reactors3%
Pumps + Compressors
3%
Economic Analysis > Operating Expenses (OPEX)
Operating Expenses – $264 million USD per year
24
Toluene Feed38%
Chlorine Feed30%Utilities
2%
Waste Treatment
2%
Other Direct Manufacturing
6%
Fixed Manufacturing
6%
General Manufacturing
16%
Economic Analysis > Profitability and Cash Flow
25
-200
-150
-100
-50
0
50
100
150
200
250
0 2 4 6 8 10 12 14
Cas
h F
low
($ M
illio
ns)
Time (years)
Non-Discounted Discounted
Operation
*
Construction
CCP = $224.6m
NPV = $102.5m
PBP = 2.78 years
DPBP = 3.30 years
DCFROR = 17.7%
* (6% interest rate for DCF)
Economic Analysis > Raw Material Price Case Study
• Current prices: 1.29 USD/kg toluene
1.30 USD/kg chlorine
26
-600
-400
-200
0
200
400
600
0 50 100 150 200
Net
Pre
sent
Val
ue
($ M
illio
n)
Percentage of Current Price (%)
Toluene Chlorine
Economic Analysis > Products Price Case Study
• Current prices: 2.69 USD/kg benzyl chloride
0.28 USD/kg hydrochloric acid
27
-1000
-500
0
500
1000
1500
0 50 100 150 200
Net
Pre
sent
Val
ue
($ M
illio
n)
Percentage of Current Price (%)
Benzyl Chloride Hydrochloric Acid
PROCESS OPTIMIZATION
28
Process Optimization > Heat Integration
• Minimize external utility requirements by exchanging heat between process streams
29
-50
0
50
100
150
200
250
-60
-10
40
90
140
190
240
0 1 2 3 4 5 6 7 8
Ho
t St
ream
Tem
pe
ratu
re (
°C)
Co
ld S
tre
am T
emp
era
ture
(°C
)
Stream ID
Cold Stream
Hot Stream
Process Optimization > Heat Integration
• Approx. 1500 kW of heat exchange between streams
• Eliminate low-pressure steam requirements
• 63% less refrigerant required, 90% less cooling water
• $8.63 million in operating savings over 10 years
30
4
6
5
7
1 32
110°C 7.31°C
RF
180°C
CW RW
CW RW
RW
210.7°C
50°C
-15°C
25°C
25°C
25°C
45°C
45°C
67.9°C
94°C
-2.69°C 21.89°C 25°C
80°C 80°C 50°C
125.9°C
66.4°C
1008 kW
213 kW198 kW
59 kW
Process Optimization > T-101 Product Recovery
31
T-100
C-101C-100
T-100 Cond.
T-100 Reboil.T-101
T-101 Cond.
T-101 Reboil.
E-102 E-103 V-105
E-104 E-105
E-106 E-107
E-108
RW
CW RW
CW RW
CW
HPS
CW
HPS
CW RF
From Reactor
Toluene to Recycle
Benzyl Chloride
Organic Wastes
Chlorine to Recycle
HCl (aq) 36 wt%
Acid Feedwater
Process Optimization > T-101 Product Recovery
• The change in fixed capital investment and utility requirements is insignificant when product recovery is increased
• $6000 reduction due to smaller E-106 and E-107
• Waste treatment costs were significantly reduced by increasing product recovery
• Approximately $2 million per year in savings
32
PROCESS SAFETY
33
Process Safety > Hazard and Operability Study (HAZOP)
• HAZOP technique used to identify and evaluate potential for hazards of the equipment in the process
• Serves to protect plant personnel, nearby residents, environment and wildlife, and the investment itself
• Results in rigorous safety measures and emergency plans
• Study conducted on the reactor and distillation column
• Chosen for their high complexity and the high throughput of the material they must process
• Ideally a HAZOP study would have been conducted for every piece of equipment
34
• The HAZOP evaluations conducted identified variations in inlet and outlet flow rates to be the most likely cause of an incident for both units
• Additional equipment inspection and maintenance of related piping and valves reduces the probability of this event occurring
• Operation can continue during a repair or blockage if backup valves and pumps/compressors are used
• A feed or cooling water supply shortage can be temporarily addressed by the 30 day supply capacity
35
Process Safety > Hazard and Operability Study (HAZOP)
• In addition to HAZOP studies, process wide hazards were identified. To address such hazards:
• Overestimation of corrosion allowance and design pressure
• Anticipated liquid level surges in vessels
• Minimize ignition sources and ensure a well ventilated area
• The reaction pathway was chosen in part for its moderate operating conditions
• Maximum process temperature = 210.7oC
• Maximum process pressure = 200 kPa
36
Process Safety > Safety Features
• Glass, Hastelloy® B and electroless nickel plating were considered for their high corrosion resistance
• Hastelloy® B selected based on cost, conductivity and yield strength
37
Process Safety > Materials of construction
Material of Construction
Material Type Bulk Material CostThermal
Conductivity[W/m·K]
Yield Strength [MPa]
Electroless Nickel Plating
Ni coated carbon steel
420 USD/mm·m2 80 -Varies with substrate
700 - Varies with substrate
Hastelloy® B® Nickel Alloy 18 - 20 USD/kg 12.1 375 - 400
SiO2 Glass Glass 1-2 USD/kg 0.2 - 0.73 70
SUMMARY AND CONCLUSIONS
38
100 kt/year
95% selectivity
High emphasis on safety and green engineering
Highly optimized
CAPEX of $96 million
OPEX of $264 million/year
NPV of $103 million (18% DCFROR in 10 years)
Summary and Conclusions
39
Thank you for listening!Questions?
UNIVERSITY OF OTTAWA DEPARTMENT OF CHEMICAL AND BIOLOGICAL ENGINEERING
FOR SNC LAVALIN PLANT DESIGN COMPETITION
Ryan Bekeris Martin Dussault Matthew Hudder Robert Tyssen
APPENDIX
41
• Pseudo-first-order reaction kinetics to represent the rate of production of organic species (liquid-phase mole fraction basis):
• Increased benzyl chloride (RCl) generation yields higher rates of production of undesired RCl2 and RCl3
Appendix > Reactor Design
42
𝑑𝑥𝑅𝐻
𝑑𝑡= −𝑘1,𝑝𝑠𝑒𝑢 𝑥𝑅𝐻
𝑑𝑥𝑅𝐶𝑙
𝑑𝑡= 𝑘1,𝑝𝑠𝑒𝑢 𝑥𝑅𝐻 − 𝑘2,𝑝𝑠𝑒𝑢 𝑥𝑅𝐶𝑙
𝑑𝑥𝑅𝐶𝑙2
𝑑𝑡= 𝑘2,𝑝𝑠𝑒𝑢 𝑥𝑅𝐶𝑙 − 𝑘3,𝑝𝑠𝑒𝑢 𝑥𝑅𝐶𝑙2
𝑑𝑥𝑅𝐶𝑙3
𝑑𝑡= 𝑘3,𝑝𝑠𝑒𝑢 𝑥𝑅𝐶𝑙2
Appendix > Reactor Design
• Reaction progression at 80°C
• Assume pure toluene in feed liquid-phase and toluene is limiting reagent
43
0
0.2
0.4
0.6
0.8
1
1.2
0 0.05 0.1 0.15 0.2 0.25 0.3
Mo
le F
ract
ion
Residence Time [hr]
RH
RCl
RCl2
RCl3
Appendix > Reactor Design
• Benzyl chloride yield vs. toluene conversion
• Limit toluene conversion to 30 percent
• 93% benzyl chloride selectivity; temperature independent
44
0
0.2
0.4
0.6
0.8
1
1.2
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
YR
Cl/
RH
Toluene Fractional Conversion
60C
80C
100C
Appendix > Reactor Design
• Arrhenius plots for rate constants:
• Temperature change yields roughly equal proportional changes in k1, k2, and k3
45
ln(k1) = -2916/T + 12.23R² = 0.975
ln(k2) = -3104/T + 10.89R² = 0.986
ln(k3)= -3677/T + 10.59R² = 0.992
-2
-1
0
1
2
3
4
5
2.80E-03 2.90E-03 3.00E-03 3.10E-03 3.20E-03
ln(k
[h
r-1])
Temperature-1 [K-1]
k1
k2
k3
Appendix > Reactor Design
• Estimation of gas-holdup:
• Properties obtained from HYSYS simulation
• Extended NRTL – Virial vapour estimation – UNIFAC VLE
• Obtain εg as a function of superficial gas velocity (Ug)
46
𝜀𝑔 = 0.672𝑓 𝑈𝑔𝜇𝑙
𝜍
0.578
𝜇𝑙
4𝑔
𝜌𝑙𝜍3
−0.134
𝜌𝑔
𝜌 𝑙
0.062
𝜇𝑔
𝜇𝑙
0.107
Property Value Units for Equation
µl 3.145 x 10-3 g/cm·s
µg 1.335 x 10-4 g/cm·s
ρl 8.983 x 10-1 g/cm3
ρg 1.801 x 10-3 g/cm3
σ 24.14 cm/s2
Appendix > Reactor Design
• Want to operate near εg = 0.3; get Ug = 0.2 m/s
• εg increases with pressure – operate at ~1 atm
• Vg = 4434 m3/h – split to 4 reactors (D = 1.4m)
47
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
εg
Superficial Gas Velocity [m/s]
Appendix > Reactor Design
• Four reactors gives sufficiently low Ug and maintains enough volume to allow proper phase contact, liquid agitation, and lighting equipment.
48
R-100 R-101 R-102 R-103
Chlorine
Prepped
Toluene
Prepped
Off gas
Liquid
Products
Appendix > Reactor Design
• Primary and secondary reactions are highly exothermic
• ΔH1 = -1.2 x 105; ΔH2 = -9.8 x 104; ΔH3 = -1.2 x 105 [kJ/mol]
• 30 percent conversion of a 323.9 kmol/h toluene feed
• 3252 kW of cooling required
• Cooling water (Cp = 4.18 kJ/kg·K) – temp range 30 – 45°C
• Obtain a cooling water requirement of 52 kg/s
• Total for all reactors – divide roughly equally
49
Appendix > Reactor Design
50
Reactor PerformanceTemperature 80°C Organic Outlet CompPressure 101.3 kPa Toluene 0.71 Pass Toluene Conversion 30% Benzyl Chloride 0.2813Benzyl Chloride Selectivity 93.8% Benzal Chloride 0.0185Gas-Holdup 0.3 Benzotrichloride 0.0002
Reactor SizingSingle Reactor Diameter 1.4 m Working Volume 2.16 m3
Single Reactor Height 2.8 m Wall Thickness 8.45 mmSingle Reactor Volume 4.32 m3 Construction Material Hastelloy® B®Liquid Height In Reactor 1.4 m Number of Identical
Reactors4
Lighting ConfigurationNumber of Lights 9 Lamp Diameter 1.27 cmLight Source Fluorescent Lamp Height 1.4 mLighting Volume Per Reactor 6.126 x 10-3 m3 Lamp Well Thickness 6.09 mm
Cooling Utility RequirementTotal Cooling Duty 3250.1 kW UA (Total) 77.27 kW/KUtility Choice Cooling Water UA (Per Reactor) 19.32 kW/KTotal Utility Requirement 51.95 kg/s
Appendix > Distillation Column Design
• Fenske equation to find minimum number of trays (4.79):
• Underwood equations to find minimum reflux ratio (0.218):
• Theoretical number of trays at 100% tray efficiency:
51
𝑁𝑚𝑖𝑛 = log
𝑥𝐿𝐾𝑥𝐻𝐾
𝐷 𝑥𝐻𝐾𝑥𝐿𝐾
𝐵
log 𝛼𝐿𝐾 𝐻𝐾 𝐴𝑣𝑒
𝛼𝑖𝑥𝑖,𝐹
𝛼𝑖 − 𝜃= 1 − 𝑞
𝑛
𝑖=1
𝑅𝑚𝑖𝑛 + 1 = 𝛼𝑖𝑥𝑖,𝐹
𝛼𝑖 − 𝜃
𝑛
𝑖=1
𝑁 − 𝑁𝑚𝑖𝑛
𝑁 + 1= 0.75 1 −
𝑅 − 𝑅𝑚𝑖𝑛
𝑅 + 1
0.566
Appendix > Distillation Column Design
• 1.5Rmin selected as operating conditions, to balance operating costs with capital costs:
52
0
2
4
6
8
10
12
14
16
18
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Nu
mb
er o
f Tra
ys (N
theo
reti
cal)
Reflux Ratio (R)
Appendix > Distillation Column Design
• Optimal feed tray selected using Kirkbride method (8):
• Actual number of trays using separation efficiency (18):
• Column diameter using empirical correlations (2.23m):
53
log 𝑁𝐷
𝑁𝐵 = 0.206 log
𝐵
𝐷
𝑥𝐻𝐾 ,𝐹
𝑥𝐿𝐾,𝐹
𝑥𝐿𝐾,𝐵
𝑥𝐻𝐾 ,𝐷
2
𝑁𝑎𝑐𝑡𝑢𝑎𝑙 =𝑁𝑡𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙
𝜀
𝐷𝑡 = 4𝐺
𝑓𝑈𝑓 𝜋 1 −2𝐴𝑑𝐴𝑇
𝜌𝐺
Appendix > Distillation Column Design
54
Parameter Value Parameter Value
Feed Molar Flow (kgmole/h) 444.75 Toluene Recovery 0.995
Distillate Molar Flow (kgmole/h) 344.92 Benzyl Chloride Recovery 0.995
Bottoms Molar Flow (kgmole/h) 99.83 Average Volatility 5.92
Condenser Temperature (°C) 111 Reboiler Temperature (°C) 209
Condenser Pressure (kPa) 150 Reboiler Pressure (kPa) 200
Nmin 4.79 Nactual 18
Rmin 0.218 Ractual 0.327
Uf (m/s) 0.729 єactual 0.75
Hc (m) 13.3 Dt (m) 2.23
Tray Type Sieve Column Type Fractional
Main Construction Material Hastelloy B Secondary Material Carbon Steel
Condenser Duty (kJ/h) -2.47 ∙ 106 Reboiler Duty (kJ/h) 1.57 ∙ 107
Condenser Area (m2) 11.21 Reboiler Area (m2) 387.7
Total Module Costs ($USD) 3.04 million
Appendix > Falling Film Absorber
• Design Equation Utilized:
• linearized-coupled mass and heat transfer model:
55
𝑑𝜔𝑠𝑏
𝑑𝐴= −𝐾𝑒𝑓𝜌𝑠
𝜔𝑎𝑣𝑔2
𝑀1 𝜔𝑠𝑏 − 𝑎 + 𝑏𝑇𝑠𝑏
𝑑𝑇𝑠𝑏
𝑑𝐴= 𝐾𝑒𝑓𝜌𝑠
𝑐𝑤𝜔𝑎𝑣𝑔2
𝑀1𝑐𝑠+
𝑖𝑣𝑠𝑀𝑠𝑐𝑠
𝜔𝑠𝑏 − 𝑎 + 𝑏𝑇𝑠𝑏 − 𝑈𝑏𝑤
𝑀𝑠𝑐𝑠 𝑇𝑠𝑏 − 𝑇𝑤
𝑁𝐴 =0.00122𝐷𝐺
𝑃𝑜𝑝𝑀1.75𝜇
𝑃𝑎𝑚 𝐴
Appendix > Falling Film Absorber
56
• HCl and Cl2 solubility in water
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100 120
Solu
bili
ty o
f Cl2
[gC
l2/g
H2O
]
Solu
bili
ty o
f H
Cl[
gHC
l/gH
2O]
Temperature [°C]
HCl
Cl2
Appendix > Plant Layout
57
• Equipment spacing used for plant layout
Equipment Distance (m)K-100 and E-100 10E-100 and E-101 1E-101 and R-100 2.4R-100 and R-101 3R-101 and R-102 3R-102 and R-103 3R-103 and E-102 + E-103 2.4E-102 + E-103 and V-105 2.4V-104 and C-100 3C-100 and E-108 2.4E-108 and C-101 2.4P-100 and T-100 4.5T-100 and T-100 reboiler 2.4T-100 reboiler and T-101 2.4T-101 and T-101 reboiler 2.4T-101 reboiler and E-104 + E-105 1E-104 + E-105 and E-106 + E-107 1
Appendix > Control Strategy Example (P&ID)
58
Appendix > Reaction Pathway Selection
• Potential alternative pathway:
• Blanc chloromethylation of benzene
• Reagent Price
59
𝐶6𝐻6 + 𝐶𝐻2𝑂 + 𝐻𝐶𝑙 𝑍𝑛𝐶 𝑙2 𝐶7𝐻7𝐶𝑙 + 𝐻2𝑂
Compound Price (USD/kg)Benzene 1.43Formaldehyde 1.10Hydrogen Chloride 3.87Zinc Chloride (Granular) 106.1
Appendix > Heat Integration
• Heat Integration
• By exchanging heat between process streams, can reduce the amount of external utility (ex. Steam, cooling water, etc.) that is required
• Summary of streams requiring heating and cooling:
60
Stream Name ID mCp (kW/°C) Tin (°C) Tout (°C) Q (kW)
Toluene to Reactor Heater 1 14.589 -2.69 80.00 1206.32
Chlorine Mixed Feed 2 1.015 21.89 80.00 59.00
HCl Acid Feedwater 3 8.504 25.00 50.00 212.60
T-100 Distillate 4 9.812 110.00 -15.00 -1226.49
T-101 Distillate 5 3.673 180.00 25.00 -569.31
T-101 Bottoms 6 0.505 210.70 25.00 -93.86
Hydrochloric Acid Product 7 9.614 50.00 25.00 -240.36
Appendix > Heat Integration
• Utility outlet temperature limits
• Total utility requirements for process stream heating and cooling
61
Utility Heating/Cooling Outlet Temperature Limit (°C)Low Pressure Steam (LPS) Heating 150 - 160 (maximum)Cooling Water (CW) Cooling 45 (minimum)Refrigerated Water (RW) Cooling -5 (minimum)Refrigerant (RF) Cooling -5 and colder
Utility Heating/Cooling Duty (kW)Low Pressure Steam (LPS) Heating 1478Cooling Water (CW) Cooling 1217Refrigerated Water (RW) Cooling 324Refrigerant (RF) Cooling 589
Appendix > Heat Integration
• Cold stream temperature-enthalpy diagram
• Energy required per temperature change
62
0
200
400
600
800
1000
1200
1400
1600
-10 0 10 20 30 40 50 60 70 80 90
Hea
t Tr
ansf
erre
d (
kW)
Temperature (°C)
Appendix > Heat Integration
• Hot stream temperature-enthalpy diagram
• Energy released per temperature change
63
-2500
-2000
-1500
-1000
-500
0
-50 0 50 100 150 200 250
Hea
t Tr
ansf
erre
d (
kW)
Temperature (°C)
Appendix > Heat Integration
• Combined temperature-enthalpy diagrams
• A total of 1478 kW of energy can be shared between process streams. (652 kW utility cooling required)
64
-1000
-500
0
500
1000
1500
2000
-50 0 50 100 150 200 250
Hea
t Tr
ansf
erre
d (
kW)
Temperature (°C)
Pinch Barrier
1478 kW
652 kW
Appendix > Heat Integration
• Can now design heat exchange network
• Can eliminate heating and reduce cooling requirements
65
C
4
6
5
7
2
1
3
80°C
80°C
50°C
-2.69°C
21.89°C
25°C
C
C
C
C = Cold Utility
110°C
180°C
210.7°C
-15°C
25°C
25°C
50°C 25°C
66.4°C
7.31°C
1008 kW
125.9°C
213 kW
67.9°C
198 kW
59 kW
94°C
80°C
50°C
218 kW
158 kW
35 kW
241 kW
Appendix > Heat Integration
• Summary of new utility requirements
• Note: Cooling water numbers refer to process stream cooling only
• Annual savings:
• LP Steam: $655k; Cooling Water: $12.4k; Refrigerant: $196k
• Save $8.6 million after 10 years of plant operation
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Utility Heating/Cooling New Duty (kW) Decrease (kW)Low Pressure Steam Heating 0 1478Cooling Water Cooling 109 1108Refrigerated Water Cooling 324 0Refrigerant Cooling 219 370
Appendix > Green Engineering Principles
1. Design process inputs and outputs to be as inherently nonhazardous as possible.2. Prevent waste, rather than treating/cleaning waste after it is formed.3. Minimize energy and material consumption for separation and purification
processes.4. Maximize energy/space/time efficiency of processes, products, and systems.5. Process should be output-pulled instead of input-pushed.6. Added complexity to a process or material is an investment with respect to design
choices on recycle/reuse.7. Focus on making processes durable; not immortal.8. Reduce designs with unnecessary capacity (i.e. "one size fits all").9. Reduce material diversity in multi-component products to promote disassembly
and to retain value.10. Design processes such that material and energy streams are integrated and
interconnected.11. Products and processes should be designed to have maximum commercial
performance.12. Use of renewable materials and energy, over depleting sources.
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