Fuel Cell Design

1
Fuel Cell Design

• Chemical Engineering
• Senior Design
• Spring 2005
• UTC

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Technical and EconomicAspects of a 25 kW Fuel
Cell

• Chris Boudreaux
• Wayne Johnson
• Nick Reinhardt

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Technical and EconomicAspects of a 25 kW Fuel
Cell

• Chemical and Thermodynamic Aspects

• Investigate the design of
• --a 25 kW Fuel Cell
• --Coproduce Hydrogen
• --Grid parallel
• --Solid Oxide Electrolyte

Our Competence
Not Our Competence
4
Outline

• Introduction to the project
• Process Description
• Process Equip. Design
• Economic Analysis

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Introduction

• Overall Reaction
• Methane Air --gt Electricity
• Hydrogen

Heat CO2
6
Introduction
Gas
Reformer
Water
SynGas
Electricity
Air
Fuel Cell
Heat
POR
Hydrogen
Pressure Swing Adsorption
Exhaust
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Fuel Cell-Chemistry
SynGas
POR
H2
H2
CO
H2O
CO2
CO
O-
O-
Air
Air
O2 N2
Solid Oxide Electrolyte is porous to O-
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Fuel Cell-Electricity
Electrons
SynGas
POR
H2
H2O
CO2
CO
Load
O-
O-
Air
Air
O2 N2
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Fuel Cell-Challenges
SynGas
POR
H2
Hot SynGas
H2
CO
H2O
CO2
CO
Recover H2
O-
O-
Air
Air
O2 N2
Hot Air
Recover Heat
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Process DescriptionTurn it over to Nick
Reinhardt
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Process Description
Fuel Preparation
Fuel Cell
Air Preparation
Post Processing
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Fuel Preparation - 100
Fuel Preparation
Fuel Cell
Air Preparation
Post Processing
13
Air Preparation - 200
Fuel Preparation
Fuel Cell
Air Preparation
Post Processing
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Fuel Cell - 300
Fuel Preparation
Fuel Cell
Air Preparation
Post Processing
15
Post Processing - 400
Fuel Preparation
Fuel Cell
Air Preparation
Post Processing
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Process and Equipment DesignTurn it over to
Chris Boudreaux
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Sulfur Purge 25C 0.0002 kmol/hr H2S 100
Desulfurizer
Pure Natural Gas 25C 0.33 kmol/hr CH4 100
Natural Gas Inlet 25C 0.33 kmol/hr CH4
99.9 H2S 0.001
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Heat Exchangers

• Aq/UF?Tlm
• F 0.9
• U 30 W/m2C
• ?Tlm (?T2 ?T1) / ln(?T2 / ?T1)

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Fuel Humidifier
POC Vent 26C
Pure NG 25C 0.3 kmol/hr CH4 100
Humidified NG 273C 0.67 kmol/hr H2O 56 CH4
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Area 2.6 m2 q 1.8 kW
Recycled Water 5C 0.37 kmol/hr H2O 100
Cooled POC 283C 3.51 kmol/hr N2 86 O2
9 H2O 4 CO2 1
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Fuel Preheater
POR 850C 1.3 kmol/hr H2O 47 H2 29 CO2
23 CO 1
Heated HNG 840C
Humidified NG 273C
Area 6.3 m2 q 5.3 kW
Cooled POR 479C
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Reformer R-104
CH4 H2O ? CO 3H2 CH4 2H2O ? CO2 4H2
Depleted Air
POC
Pure NG
SynGas
Heated HNG
q 17 kW
SynGas 734C 1.26 kmol/hr H2 73 CO 21 H2O
3 CO2 2
Heated HNG 840C 0.67 kmol/hr H2O 56 CH4 44
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Combustor COMB-105
CH4 2O2 ? CO2 2H2O
Depleted Air
POC
Pure NG
SynGas
Heated HNG
q -17 kW
Depleted Air 850C 3.48 kmol/hr N2 87 O2
11 H2O 2
POC 784C 3.51 kmol/hr N2 86 O2 9 H2O
4 CO2 1
Pure NG 25C 0.03 kmol/hr CH4 100
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Water Gas Shift Reactor
CO H2O ? CO2 H2
WGS Exhaust 480C 1.26 kmol/hr H2O 46.5 H2
30 CO2 23.2 CO 0.3
Cooled POR 480C 1.3 kmol/hr H2O 47 H2
29 CO2 23 CO 1
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Fuel Cell
Depleted Air 850C 3.48 kmol/hr O2 11.5
CO ½ O2 ? CO2 H2 ½ O2 ? H2O
SynGas 750C 1.26 kmol/hr H2 73 CO 21 H2O
3 CO2 2
POR 850C 1.3 kmol/hr H2O 47 H2 29 CO2
23 CO 1
Heated Air 650C 3.88 kmol/hr O2 21
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Pressure Swing Adsorber
H Exhaust 25C 0.38 kmol/hr H2 100
Air Inlet 25C 0.13 kmol/hr
Uncondensed Gases 5C 0.68 kmol/hr H2 56 CO2
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Purge 25C 0.43 kmol/hr CO2 68
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Economic AnalysisTurn it over to Wayne Johnson
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Economic Components

• Capital Costs
• Operating Costs
• Income Generated
• Payback Period
• Return on Investment

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Capital Cost Assumptions

• Cap Cost Program
• Analysis, Synthesis, and Design of Chemical
  Processes
• Compares to Peters and Timmerhaus
• Stainless Steel

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Equipment Costs
30
Lang Factor

• Fluid Processing 4.74
• Includes
• Construction material and overhead
• Labor
• Contract engineering
• Contingency
• Site development
• 40,000 X 4.74 190,000

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Operating Costs

• Fuel 0.33 kmol/hr
• 260,000 BTU/hr
• 0.26 therms/hr
• Tennessee Valley industrial rate
• 7.70/therm
• Labor included at site

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Income

• Electricity 25kW
• Price 0.10/kWhr
• Hydrogen 0.38 kmol/hr
• .76 kg/hr
• Tennessee Valley industrial rate
• 11.64/kg

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Total Income vs. Expense
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Investment Results

• Non-discounted Payback
• 2.4 Years
• Return on Investment
• 41

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Conclusions

• Rate of return and payback period are interesting
• Emerging technology means cost may decrease

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Questions for the Board

• What areas require more detail?
• What locations should be investigated?
• Should we enlist an electro-chemistry team?
• Should we enlist an electrical engineering team?