Fuel Cell

1
Fuel Cell
Heat
REVISION LIST -- To be removed before final
presentation .JMH -- 20/april/05 330 pm Ive
rearranged some of the nick slides -- it is more
in line with the flow of the process. Ive
taken some things out. Ive made the background
with header footer on all but Title slide I
added the PFD repeatedly in nicks section to
bring the viewer back home Ive partially
covered the non-circled parts of the PFD when
showing a new section Ive enlarged all the PFD
images to max I put some of your pictures here
there Ive added the Turn it over
introductions Ive revised and corrected the fuel
cell details
2
Fuel Cell Design

• ENCH 340
• Spring, 2005
• UTC

3
Technical and EconomicAspects of a 25 kW Fuel
Cell

• Chris Boudreaux
• Jim Henry, P.E.
• Wayne Johnson
• Nick Reinhardt

4
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
5
Outline

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

6
Introduction

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

Heat CO2
7
Introduction
Gas
Reformer
Water
SynGas
Electricity
Air
Fuel Cell
Heat
POC
Hydrogen
Pressure Swing Absorption
Exhaust
8
Fuel Cell-Chemistry
SynGas
POC
H2
H2
CO
H2O
CO2
CO
O-
O-
Air
Air
O2 N2
Solid Oxide Electrolyte is porous to O-
9
Fuel Cell-Electricity
Electrons
SynGas
POC
H2
H2O
CO2
CO
Load
O-
O-
Air
Air
O2 N2
10
Fuel Cell-Challenges
SynGas
POC
H2
Hot SynGas
H2
CO
H2O
CO2
CO
Recover H2
O-
O-
Air
Air
O2 N2
Hot Air
Recover Heat
11
Process DescriptionTurn it over to Nick
Reinhardt
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SOFC PFD
13
Fuel Preparation - 100
14
Desulfurizer (DS 101)

• 2 ppm H2S in natural gas feed
• H2S removed in DS-101 with disposable carbon
  filters
• 10 of CH4 fed to combustor
• 90 of CH4 fed fuel humidifier

15
Fuel Humidifier (FH 102)

• 1.25 Kmol H20 per Kmol CH4 fed to FH-102
• Heat provided from combustor exhaust

16
Fuel Preheater (HX 103)

• Heat provided from fuel cell exhaust

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Reformer (R 104)

• Equilibrium determined to be
• 85 CH4 ? CO
• 15 CH4 ? CO2
• CH4 H2O ? CO 3H2
• CH4 2H2O ? CO2 4H2
• Heat provided from reaction in combustor

18
Combustor (COMB 105)

• Extent of reaction for combustion assumed to be
  100
• CH4 2O2 ? CO2 2H2O
• Necessary O2 provided from fuel cell air exhaust

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SOFC PFD
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Air Handling and WGS - 200
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Air Compressor (COMP 224)

• Air intake for the system
• 6.65 standard cubic meters per minute flow

22
Air Preheater (HX 223)

• Heat provided by water gas shift exhaust

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Water Gas Shift (WGS 222)

• CO H2O ? CO2 H2
• Equilibrium determined to be 94

24
Air Side Heat Recovery (HX 221)

• Heat provided by combustor exhaust

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SOFC PFD
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Fuel Cell - 300
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Fuel Cell (FC 331)

• CO ½ O2 ? CO2 (100)
• H2 ½ O2 ? H2O (50)
• DH to electricity 50

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SOFC PFD
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Post Processing
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Fuel Exhaust Condenser (HX 443)

• Uses external cooling source
• Condenses process water from exhaust gases
• Condensed water flows to WP-441
• Non-condensible exhaust flows to comp-445 and PSA
  system
• 99.5 of water is condensed

31
Chiller (Ref 446)

• Provides cold water utility for HX-443
• Supply temp 0C
• Return temp 50C
• Rate 1.8 gpm
• Cooling 35,500 kJ/hr (9.9kW)
• Power 2.4 kW to run

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PSA Compressor (COMP 445)

• Provides dried, compressed exhaust gas to the PSA
  system.
• 2 stage compressor

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Pressure Swing Adsorber (PS 442)

• Uses custom adsorbant to purify hydrogen
• 80-90 recovery possible
• 99.9 purity on the product gas achievable with
  slight recovery cost
• Delivery pressure 20 bar
• Recovered Hydrogen .177 kmol/hr _at_ 90

34
Hydrogen Compressor (COMP 447)

• Produced compressed hydrogen for sale
• Multi-stage compressor
• Pressure input 2-20 bar
• Pressure output 200 bar

35
Water Purifier (WP 441)

• Basic cartridge filtration of incoming water
  (either city supply or process supply)
• Excess process water discharged to city sewer

36
Water Pump (P 444)

• Supplies water to section 100 fuel humidifier

37
Process and Equipment DesignTurn it over to
Chris Boudreaux
38
SOFC PFD
39
(No Transcript)
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(No Transcript)
41
Equipment Assumptions

• All equipment was assumed to be stainless steel

42
Heat Exchangers

• 10 approach temperature was used
• q UAF?Tlm
• F 0.9
• U 30 W/m2C
• ?Tlm (?T2 ?T1) / ln(?T2 / ?T1)

43
Pumps and Compressors

• Power mz1RT1(P2/P1a 1)/a
• T1 inlet temp
• R Gas Constant
• Z1 compressibility
• m molar flow rate
• a (k-1)/k
• k Cp / Cv

44
Other

• PSA, WGS, and desulfurizer have purchased
  internals

45
Economic AnalysisTurn it over to Wayne Johnson
46
Economic Components

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

47
Capital Cost Assumptions

• Cap Cost Program
• Stainless Steel
• Minimum Size Basis for all components

48
Capcost Output
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Capital Costs
50
Sizing Adjustments

• Equation from Text
• Ca/Cb (Aa/Ab)n
• Ca Cost of Desired Equipment
• Cb Cost of Base Equipment
• Aa Desired Cost Attribute
• Ab Base Cost Attribute
• n Cost Exponent (0.6)

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Sizing Adjustments

• Ab 450 kilowatts Cb 150,000
• Aa 1.2 kilowatts n 0.6
• Total adjusted cost 4,282

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Adjusted Costs
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Total Installation

• Total Equipment cost 51,474
• Lang factor 4.74 for fluid processing plant
• Total Installation 243,985

54
Operating Costs

• Fuel 158,000 BTU/hr
• 0.158 therms/hr
• Fuji Hunt price 7.7/therm
• Labor 24 hr coverage with 4 shifts
• Average salary 30K
• Benefits 2x salary
• Total 240,000 annually
• Use contract labor

55
Income

• Electricity 25kW
• Price 0.05/kWhr
• Hydrogen 0.18 kmol/hr
• .35 kg/hr
• Fuji Hunt price 11.64/kg

56
Total Income vs. Expense
57
Investment Results

• Non-discounted Payback
• 7.4 Years
• Return on Investment
• 13.5

58
Conclusions

• Materials are expensive
• Operation is expensive
• Electricity costs are low
• Fuel cell not recommended at this time

59
Questions?
60
Alternative

• CH4 2H2O CO2 4H2
• Currently 0.2kmol CH4 0.18kmol of H2
• Revenue 35,000 in H2 sales
• Potential revenue at 50 H2 recovery
  70,000

61
Alternative

• Remove fuel cell
• Optimize reformer and WGS for H2 generation
• H2 is only product

62

63
Fuel Cell
Heat
. Objective Develop and demonstrate a 25 kW, grid
parallel, solid oxide fuel cell system that
coproduces hydrogen. , the installation be
configured to simultaneously and efficiently
produce hydrogen from a commercial natural gas
feedstream in addition to electricity. This
ability to produce both hydrogen and electricity
at the point of use provides an early and
economical pathway to hydrogen production. .
Ceramic processing and challenges in the design
and manufacturing process of SOFCs will be
addressed . The amount of hydrogen that the
unit produces may be controlled by the adjusting
the natural gas flow at steady power production
(i.e., adjusting the fuel utilization). A nominal
production rate of 25 kg of hydrogen per day
falls within the expected upper and lower
utilization limits for 25 kW electricity
production. The system produces a hydrogen-rich
exhaust stream that will be purified using a
Pressure Swing Absorption (PSA) unit. The
hydrogen flow and purity are interdependent. It
is expected that purity gt98 is achievable for
flows of 2-3 kg/day. Critical impurities, such as
CO and CO2 will be measured. It is not clear
that this size system makes sense for commercial
production. We are looking at a 25 kW module as a
building block for commercial production to begin
in 2006. The size of the 25 kW module is
estimated to be smaller than a 5 ft cube. The
cost of early commercial systems is expected to
be lt10K/kW