TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes

ACQUISITION PROGRAM: PEO Ships, Electric Ship Office

OBJECTIVE: Development of a 250KW electrical-equivalent, hydrogen flow (EEHF) reformate purification system for shipboard operation.

DESCRIPTION: Fuel cells are a very attractive shipboard technology, not only for the fuel efficiency savings (est. 20% per vessel) but inherent modularity which dramatically improves the ease of shipboard installation and general maintenance. Other benefits of fuel cells include a significant reduction of heat, noise signatures and air requirements over the traditional power generation modules. However, fuel cells depend on a pure supply of hydrogen and today�s reformate technology cannot deliver hydrogen in the purity and quantity required for shipboard operation.

Current hydrogen reformate technology enables the US Navy to reform logistics fuel to produce hydrogen, the preferred fuel source for high-efficiency fuel cells. However, the hydrogen stream produced by this reformation contains many compounds such as CO, CO2, H2S, etc. These compounds have proven to be harmful to fuel cells, leading to shortened life, and in many cases, loss of operation due to contamination. Today, there is no large-scale, economically-viable technology capable of separating hydrogen from these harmful contaminants; existing technologies require either the use of precious metals or very high pressures (over 7 atms.). As a result, the hydrogen purification process is either cost-prohibitive, or overly complex, exceeding the temperature and pressure limitations of the current, highly-efficient HTPEM-based fuel cell generator technology.

The Navy seeks to develop a robust purifier capable of continuously filtering hydrogen reformate streams in a shipboard environment, given space constraints, shock requirements and fluctuating hydrogen streams. The system should demonstrate the continuous removal of H2S, CO, CO2 from a reformate stream while maximizing the hydrogen output for PEM fuel cell utilization. Additional removal of N2 would be advantageous, but it is not required. The solution must minimize system size, complexity, and potential fabrication costs while enabling modular packaging (modular: able to disassemble to a hatchable dimension of a 26" x 66" oval and re-assembled at point of installation; weight: maximum 500 lbs per module). The separator technology should maximize the H2 output and maintain consistent product quality while meeting the following operational and performance parameters:

- Operational: System should be able to handle pressure ranges of 1-4 atms, with a pressure drop of no more than 2 atms. Desired temperature operations are within 140-180 oC range, with a system volumetric density of 250 W/L.

- Performance: Minimize all impurities within the hydrogen reformate stream, notably H2S (to < 10 ppm), CO (to < 100 ppm), and CO2. Removal of N2 is desirable, however should not degenerate the other performance and operational metrics. The purifier must be able to output hydrogen at a rate which allows the fuel cell to generate electricity at a cost comparable to logistics fuel ($3,000 /1500 kWh). The reformer technologies which will be supplying the hydrogen reformate stream are operating at 35-40% efficiencies; overall system efficiency is critical.

PHASE I: Demonstrate the feasibility of the development of a 250 kW EEHF reformate purifier system which meets the above listed thresholds and is capable of integrating into a shipboard fuel cell power generation unit. Evaluate the attributes of the system, including volumetric density, material characteristics, operation and performance, dynamic response, anticipated life, anticipated maintenance requirements, ability to withstand a shipboard environment, and thermal impact using detailed models or small subscale components. Submit a Phase II development approach, performance goals and schedule containing discrete milestones for product development.

PHASE II: Finalize the design concept from Phase I and fabricate a prototype 250kW separation device. In a laboratory environment, demonstrate that the prototype meets the performance goals established in Phase I. Perform a membrane material life test for a minimum of 500 hours under the specified design operating conditions.

PHASE III: Demonstrate proposed installation, maintenance, repair, and regeneration methodologies. Develop a cost/benefit analysis and perform testing and validation. Provide detailed drawings, specifications and validation data.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This technology is a critical enabler for fuel cell operability, allowing an on-demand, low-cost, and robust source for pure hydrogen fuel. The technology can be easily extended to the semi-conductor and chemicals industry for hydrogen purification processes in their production facilities. The technology of capturing CO and CO2 may have far broader application in capturing emissions from power stations and manufacturing facilities, assisting the industries in meeting future stringent control of green house gasses.

REFERENCES:
1. Lin, H., E. van Wagner, B.D. Freeman, L.G. Toy, and R.P. Gupta, "Plasticization-Enhanced H2 Purification Using Polymeric Membranes," Science, 311(5761), 639-642 (2006 ).

2. Zou, Jian, Jin Huang, W.S. Winston Ho, "CO2 � Selective Water gas Shift membrane Reactor for Fuel Cell Hydrogen Processing," Ind. Eng. Chem Res., 46, 2272-2279 (2007).

3. Heinzel, John, Mark Cervi, Anthony Nickens, Donald Hoffman, John Kuseian, "Fuel Cell System Models for U.S. Navy Shipboard Applications," Fuel Cell Seminar Palm Springs, (2005).

4. http://www.eere.energy.gov/hydrogenandfuelcells/fuelcells/annual_review2002.html

5. 2004 Annual Progress Report, Hydrogen, Fuel Cells & Infrastructure Technologies Program (www.eere.energy.gov/hydrogenandfuelcells. Link is under "Site Updates".).

6. "FutureGen � Tomorrow�s Pollution-Free Power Plant," U.S. DOE Office of Fossil Energy Web site.
(URL: http://www.fossil.energy.gov/programs/powersystems/futuregen/index.html)

7. "Hydrogen and Clean Fuels Research," U.S.DOE Office of Fossil Energy Web site. (URL: http://www.fe.doe.gov/programs/fuels/index.html)

KEYWORDS: Fuel cell; membrane separator; reformate; modular; hydrogen; purifier