Fuel Cell Heat REVISION LIST -- To be removed before final presentation.JMH -- 20/april/05 3:30 pm I’ve rearranged some of the nick slides -- it is more in line with the “flow” of the process. I’ve taken some things out. I’ve made the background with header & footer on all but Title slide I added the PFD repeatedly in nick’s section to “bring the viewer back home” I’ve partially covered the non-circled parts of the PFD when showing a new section I’ve enlarged all the PFD images to max I put some of your pictures here & there I’ve added the “Turn it over” introductions I’ve revised and corrected the fuel cell details

Fuel Cell Design ENCH 340 Spring, 2005 UTC

Technical and Economic Aspects of a 25 kW Fuel Cell Chris Boudreaux Jim Henry, P.E. Wayne Johnson Nick Reinhardt

Technical and Economic Aspects of a 25 kW Fuel Cell Investigate the design of --a 25 kW Fuel Cell --Coproduce Hydrogen --Grid parallel --Solid Oxide Electrolyte Chemical and Thermodynamic Aspects Our Competence Not Our Competence

Outline Introduction to the project Process Description Process & Equip. Design Economic Analysis

Introduction Overall Reaction Methane + Air --> Electricity + Hydrogen + Heat + CO 2

Introduction Pressure Swing Absorption Fuel Cell Reformer Gas Hydrogen Electricity Air Heat SynGas POC Water Exhaust

Fuel Cell-Chemistry SynGas Air O-O- O-O- H2H2 H2OH2O CO CO 2 POC O 2 N 2 “Air” Solid Oxide Electrolyte Is porous to O - H2H2 + CO

Fuel Cell-Electricity SynGas Air O-O- O-O- H2H2 H2OH2O CO CO 2 POC O 2 N 2 “Air” Electrons Load

Fuel Cell-Challenges SynGas Air O-O- O-O- H2H2 H2OH2O CO CO 2 POC O 2 N 2 “Air” H2H2 + CO Hot SynGas Hot Air Recover H 2 Recover Heat

Process Description Turn it over to Nick Reinhardt

SOFC PFD

Fuel Preparation - 100

Desulfurizer (DS 101) 2 ppm H 2 S in natural gas feed H 2 S removed in DS- 101 with disposable carbon filters 10% of CH 4 fed to combustor 90% of CH 4 fed fuel humidifier

Fuel Humidifier (FH 102) 1.25 Kmol H 2 0 per Kmol CH 4 fed to FH-102 Heat provided from combustor exhaust

Fuel Preheater (HX 103) Heat provided from fuel cell exhaust

Reformer (R 104) Equilibrium determined to be: –85% CH 4 → CO –15% CH 4 → CO 2 CH 4 + H 2 O → CO + 3H 2 CH 4 + 2H 2 O → CO 2 + 4H 2 Heat provided from reaction in combustor

Combustor (COMB 105) Extent of reaction for combustion assumed to be 100% CH 4 + 2O 2 → CO 2 + 2H 2 O Necessary O 2 provided from fuel cell air exhaust

SOFC PFD

Air Handling and WGS - 200

Air Compressor (COMP 224) Air intake for the system 6.65 standard cubic meters per minute flow

Air Preheater (HX 223) Heat provided by water gas shift exhaust

Water Gas Shift (WGS 222) CO + H 2 O → CO 2 + H 2 Equilibrium determined to be 94%

Air Side Heat Recovery (HX 221) Heat provided by combustor exhaust

SOFC PFD

Fuel Cell - 300

Fuel Cell (FC 331)

SOFC PFD

Post Processing

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

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

PSA Compressor (COMP 445) Provides dried, compressed exhaust gas to the PSA system. 2 stage compressor

Pressure Swing Adsorber (PS 442) Uses custom adsorbant to purify hydrogen 80-90% recovery possible purity on the product gas achievable with slight recovery cost Delivery pressure 20 bar Recovered Hydrogen = %

Produced compressed hydrogen for sale Multi-stage compressor Pressure input = 2-20 bar Pressure output = 200 bar Hydrogen Compressor (COMP 447)

Water Purifier (WP 441) Basic cartridge filtration of incoming water (either city supply or process supply) Excess process water discharged to city sewer

Water Pump (P 444) Supplies water to section 100 fuel humidifier

Process and Equipment Design Turn it over to Chris Boudreaux

SOFC PFD

Equipment Assumptions All equipment was assumed to be stainless steel

Heat Exchangers 10° approach temperature was used q = UAFΔT lm F = 0.9 U = 30 W/m 2 °C ΔT lm = (ΔT 2 – ΔT 1 ) / [ ln(ΔT 2 / ΔT 1 ) ]

Pumps and Compressors Power = mz 1 RT 1 [({P 2 /P 1 } a – 1)]/a –T 1 = inlet temp –R = Gas Constant –Z 1 = compressibility –m = molar flow rate –a = (k-1)/k –k = C p / C v

Other PSA, WGS, and desulfurizer have purchased internals

Economic Analysis Turn it over to Wayne Johnson

Economic Components Capital Costs Operating Costs Income Generated Payback Period Return on Investment

Capital Cost Assumptions Cap Cost Program Stainless Steel Minimum Size Basis for all components

Capcost Output

Capital Costs

Sizing Adjustments Equation from Text C a /C b = (A a /A b ) n C a = Cost of Desired Equipment C b = Cost of Base Equipment A a = Desired Cost Attribute A b = Base Cost Attribute n = Cost Exponent (0.6)

Sizing Adjustments A b = 450 kilowatts C b = $150,000 A a = 1.2 kilowattsn = 0.6 Total adjusted cost = $4,282

Adjusted Costs

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

Operating Costs Fuel = 158,000 BTU/hr = 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

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

Total Income vs. Expense

Investment Results Non-discounted Payback = 7.4 Years Return on Investment = 13.5%

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

Questions?

Alternative CH 4 + 2H 2 OCO 2 + 4H 2 Currently 0.2kmol CH kmol of H 2 Revenue = $35,000 in H 2 sales Potential revenue at 50% H 2 recovery = $70,000

Alternative Remove fuel cell Optimize reformer and WGS for H 2 generation H 2 is only product

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 >98% 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 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 <$10K/kW