Comparison of On-board Hydrogen Storage Options

Transcription

1 Comparison of On-board Hydrogen Storage Options Fuel Cell Seminar November 14-18, 2005 Stephen Lasher Eric Carlson John Bowman Yong Yang Mark Marion TIAX LLC 15 Acorn Park Cambridge, MA Tel Fax Reference: D TIAX LLC 0

2 Project Overview Background We are in the process of evaluating the performance and cost of various hydrogen storage options for the DOE. Well-to-Wheels Vehicle Integration Storage System Water Electrolyzer Material Fuel Cell 125 kw Battery Motor H 2 Storage Material wt % P, T requirement Thermo, kinetics BOP requirements System size, cost System issues Power unit and thermal integration Vehicle cost, weight Fuel economy Fuel chain requirement Ownership cost WTW energy use, GHG 1

3 Project Overview Approach On-board cost and performance estimates are based on detailed technology assessment and cost modeling. Performance and Tech Assessment Literature Review System Design and Configurations Process Modeling Outline Assumptions Developer Feedback Cost Modeling Document BOM Determine Material Costs Identify Processes and Mnf. Equipment Sensitivity Analyses Overall Model Refinement Developer and Stakeholder Feedback Revise Assumptions and Model Inputs Interconnect Forming of Interconnect Shear Interconnect Paint Braze onto Interconnect Braze $14 $12 Assembly & Inspection BOP Anode Anode Powder Prep Tape Cast Slip Cast Electrolyte Electrolyte Small Powder Prep Vacuum Plasma Spray Screen Print Fabrication Blanking / Slicing Sinter in Air 1400C QC Leak Check Cathode Cathode Small Powder Prep Screen Print Vacuum Plasma Spray Sinter in Air Finish Edges System Cost, $/kwh $10 $8 $6 $4 Dehydriding Subsystem Tank Media Slurry Slurry Spray Spray Note: Alternative production processes appear in gray to the bottom of actual production processes assumed Stack Assembly $2 $0 TIAX Base Case 5,000 psi 10,000 psi 2

4 Project Overview Scope To date, we have evaluated compressed gas tanks, sodium alanate, and sodium borohydride storage technologies. Category Initial Cases Tech Status Storage State H 2 Release Refueling Compressed and Liquid Hydrogen 5,000 & 10,000 psi Mature (low volume) Gas Pressure regulator H 2 gas Reversible Onboard: Metal Hydrides, Alanates Sodium Alanate Proof of Concept Solid Endothermic desorption H 2 gas and HTF loop Regenerable Offboard: Chemical Hydrides Sodium Borohydride Early Prototype Aqueous solution Exothermic hydrolysis Aqueous solution in/out High Surface Area Sorbents: Carbon TBD R&D Solid (low T?) Endothermic desorption H 2 gas (low T?) 1 HTF = Heat Transfer Fluid 3

5 System Designs Compressed Hydrogen Tank Two type III compressed hydrogen tanks were designed to accommodate 5,000 and 10,000 psi storage pressures. Metal Boss (aluminum) for Tank Access (some constructions may also use a plug on the other end) Liner (polymer, metal, laminate) HDPE 6.3 mm thick Al 2.3 mm thick Wound Carbon Fiber Structural Layer with Resin Impregnation (V f CF:Epoxy 0.6:0.4; W f 68/32) Impact Resistant Foam End Dome Damage Resistant Outer Layer (typically glass fiber wound) 4

6 System Designs Sodium Alanate Tank A sodium alanate storage tank was designed to accommodate both high pressure and rapid heat exchange. 1.5m HTF HTF Manifold Insulation 4% Al foam GF 3 diameter size CF Liner Sintered SS Filters 0.5m H 2 Legend Metal Foam Al = Aluminum GF = Glass Fiber CF = Carbon Fiber HTF = Heat Transfer Fluid HX = Heat Exchanger SS = Stainless Steel 5

7 System Designs Sodium Borohydride Components A sodium borohydride storage system was designed to accommodate solution storage and water management. Storage Tank Reactor 696 mm 80 mm Condenser Liquid Separator 222 mm H 2, water vapor & aqueous borates H 2 & water vapor Aqueous borates? 57 mm 6

8 System Designs Sodium Alanate Tank Manufacturing Manufacturing processes and equipment are determined based on the individual component designs. Shape Al Foam Optional Process: Shape Al Foam Fill in NaAlH4 and Binder into Al Foam Form Al /SS 316 Can Sintering Pack Into Solid Status Assembly Al Form into Can Fill in Hydrides Machining End Plates Size SS 316 Tubes Brazing Tubes and One End Plate Extrusion Cylinder Stamp Semi-Sphere Cap Machining Two Bosses Spin Seal Ends To Form Cylinder *Super Binder needs to be discovered. Insert Al Foam Packs and Separators Laser Brazing HE End Plate Bend Tubes Fabricate Fluid End plates Brazing Fluid End Plates With Two Tubes Laser Brazing End Plates With Fluid Plates Insert Hydride And Heat Exchanger Into Liner Laser Brazing Liner End Cap Heat Exchange Fluid In-Out Side In this case, we assume a tank manufacturing process that loads the alanate in automated steps. 7

9 System Designs Sodium Alanate System The complete storage systems require significant BOP for overall flow control and thermal management. Fill Station Interface Refueling Interface Hydrogen H bar HTF ~100 C HTF ~125 C Check Valve in Fill Port HTF** In HTF Out Pressure Relief Valve Storage Tank Sodium Alanate Pressure Vessel w/ In-tank Heat Exchanger Temperature Transducer Pressure Transducer Thermal Relief Device Pressure Relief Valve Temperature Transducer Check Valve Dehydriding System Combustion Air Blower Heat Exchanger w/ Low NO x H 2 Combustor Motor M Pump Ball Valve Solenoid Valve (Normally Closed) Primary Pressure Regulator Hydrogen Line Heat Transfer Line Data & Comm. Line Fill System Control Module Data & Comm. Line to Fuel Control Solenoid Valve (Normally Closed) Check Valve Hydrogen Line to Fuel Cell *Note: Schematic is representative only. 8

10 System Designs Caveats We have evaluated system designs based on the current technology, which does not always meet DOE targets. Transient and Start-up Material Life Safety Issues Refueling Comments/Impact of Meeting Target Additional components or advanced designs may be needed May impact on-board efficiency and usable hydrogen stored Limited amount of real-world data Reformulated materials or advanced designs may be needed Major impact on life-cycle cost May impact on-board efficiency and usable hydrogen stored if material performance degrades over time Not all systems will have the same inherent safety Additional components will be needed Off-board requirements will be very different Major impact on life-cycle cost and fuel chain efficiency May impact on-board efficiency and usable hydrogen stored Not all systems will perform exactly the same 9

11 Results Weight Comparison Compressed hydrogen storage at 5,000 and 10,000 psi resulted in the lowest overall system weight % BOP Water Recovery Sub-system Catalytic Reactor System Weight, kg Wt% = 3.2% 6.7% 6.3% Dehydriding Subsystem Tank Media / H2 / Void 2007 Target = 4.5 wt% 0 Sodium Borohydride Sodium Alanate 5,000 psi 10,000 psi 10

12 Results Volume Comparison Sodium borohydride system with volume exchange design would be somewhat smaller than a 10,000 psi system BOP Water Recovery Sub-system System Volume, L kwh/l = Catalytic Reactor Dehydriding Subsystem Tank Media / H2 / Void 2007 Target = 1.2 kwh/l 0 Sodium Borohydride Sodium Alanate 5,000 psi 10,000 psi Note: Volume results do not include void spaces between components (i.e., no packing factor was applied). 11

13 Results Cost Comparison Factory cost of the sodium borohydride system is projected to be lower than the other systems evaluated thus far. System Cost, $/kwh $20 $18 $16 $14 $12 $10 $8 $6 $4 $2 Assembly & Inspection BOP Water Recovery Sub-system Catalytic Reactor Dehydriding Subsystem Tank Media / H2 / Void 2007 Target = $6/kWh $0 Sodium Borohydride Sodium Alanate 5,000 psi 10,000 psi Note: Factory cost results do not include refueling costs over the life of the storage system. 12

14 Conclusions Initial Cases Both basic research and system-level engineering need to continue if a viable storage system is to be developed. Technology 5,000 & 10,000 psi Sodium Alanate Sodium Borohydride Potential Advantages High gravimetric density Most mature Relatively low fuel cost Relatively high fuel chain efficiency Lower-pressure storage Relatively low fuel cost Relatively high fuel chain efficiency Conformable tank Low factory cost Low-pressure storage Pumpable Potential Disadvantages Will not meet volumetric density target High factory cost High-pressure storage Low gravimetric density High factory cost High energy, P, T requirements Slow startup One-tank design and water management challenges Fuel cost and fuel chain efficiency TBD 13

15 Conclusions Next Steps We will continue to support DOE and the Grand Challenge participants as they refine designs, processes, and materials. Preliminary results will continue to be refined based on developer/stakeholder feedback and progress Off-board (WTT) analysis will begin on the initial cases Task 1 report will summarize the results for the initial cases Work with DOE, ANL and COEs to select and evaluate new cases 14

16 Acknowledgment Thanks to DOE and the Office of Hydrogen, Fuel Cells & Infrastructure Technologies Steve Chalk, Sunita Satyapal, Carole Read, Grace Ordaz Input from the Centers of Excellence, developers, National Labs, and stakeholders UTRC and MCell Teams ANL, SNL, SRNL, LLNL Hydrogen Storage and Delivery Tech Teams Rest of the project team Gas Technology Institute, Prof. Robert Crabtree (Yale University), Prof. Daniel Resasco (U. of Oklahoma) 15