Fuel reformers

Like M( F(7s, S()F(7s can integrate fuel reforming within the fuel cell stack, A prereformer converts a substantial amount of the natural gas using waste heat from the fuel cell, (iornpoiinds containing sulfur (e,g, thiophene, which is cornrnonlv added to natural gas as an odorant) must be removed before the reformer. Typically, a hvdrodesiilfii-rizer combined with a zinc oxide absorber is used. 

Nature as model for micro-reactor development general advantages of micro flow onset of industrial interest micro heat exchanger vision of mefhanol-fuel reforming costs stiU too prohibitive [231],... 

FUEL REFORMING FOR HYDROGEN PRODUCTION SEPARATION PROCESS FOR FUEL REFORMING... 

Fuel reforming is popular way for hydrogen production for fuel cell use. Hydrocarbons are used for the fuel resource. Methane (CH4) steam reforming process consists of the following two gas phase reactions with various catalysts. 

Figure 225. Separation processes for enhancement of H2 yield in fuel reforming...

Carbon Dioxide Separation for Fuel Reforming Carbon dioxide separation reforming in the above mentioned is one of useful methodologies for efficient hydrogen production [29]. Calcium oxide (CaO) carbonation can absorb CO2 from the reformed gas and fix it. 

Kato, Y., K. Ando, and Y. Yoshizawa, 2003. Study on a regenerative fuel reformer for a zero-emission vehicle system, J. Chem. Eng. Japan, 36 (7), 860-866. 

Kreutz, T., Steinbugler, M., and Ogden, J., Onboard fuel reformers for fuel cell vehicles Equilibrium, kinetic and system modeling, Proc. 1996 Fuel Cell Seminar, Orlando, FL, 714, 1996. 

Pettersson, L. and Westerholm, R., State of the art of multi-fuel reformers for fuel cell vehicles Problem identification and research needs, Int. ]. Hydrogen Energ., 26, 243, 2001. 

Tsolakis, A., Low temperature exhaust fuel reforming of diesel fuel, Fuel, 83,1837, 2004. 

Muradov, N., Emission-free fuel reformers for mobile and portable fuel cell applications, J. Power Sourc., 118, 320, 2003. 

Although considerable research has been conducted with Pd-alloy foils, tubes, and thinner composite membranes, long-term durability and stability need to be further demonstrated, especially in the fuel reforming or WGS operating conditions, for acceptance of this technology in a commercial sector. Furthermore, mass-scale and cost-effective production of industrial-scale Pd-alloy thin-film composite membranes need to be demonstrated to be competitive in the hydrogen production and purification market. 

Little, A.D., Multi-fuel Reformers for Fuel Cells Used in Transportation. Assessment of Hydrogen Storage Technologies. Phase I. Final Report, United States Department of Energy, Office of Transportation Technologies, March 1994. 

Fuel-reforming process should be understood in a broader sense as including all options such as partial oxidation (POX), steam reforming (SR), and their combination, i.e., autothermal reforming (ATR). In general, the fuel-reforming process can be represented by the following equation ... 

The product composition from the fuel reformer generally consists of 35 to 40% H2 and 6 to 10% CO balanced with H20, C02, and N2 [39], The CO is further reduced to 2 to 3% by HT WGS and then down to <0.5% CO with LT WGS. It is not possible to reduce the concentration of CO down to a few ppm with LT WGS because of equilibrium constraints. This has to be done with preferential oxidation of CO in the last step. However, owing to the development of high-temperature PEMFC... 

R. Westerholm, L.J. Pettersson, State of the Art Multi-Fuel Reformers for Automotive Fuel Cell Applications Problem Identification and Research Needs, KFB Swedish Transport Communications Research Board, Stockholm, October 31, 1999. 

The liquid fuel reformer that has been worked on at Los Alamos and the Argonne National Labs is a fuel-flexible processor which can reform gasoline, natural gas, methanol, or ethanol at the control of a switch. This would also allow the use of the existing fuel infrastructure, but this... 

Fuel cells o fer important advantages as a power source, such as the potential for high efficiency, clean exhaust gases and quiet operation. In addition, the direct methanol fuel cell offers special benefits as a power source for transportation, such as potential high energy density, no need for a fuel reformer and a quick response. These advantages, however, have not been fully realized yet. One of the problems is the poor performance of the fiiel electrode. Even platimun, which seems the most active single element for methanol oxidation in add media, loses its electrocatalytic activity rapidly by the accumulation of adsorbed partially oxidized products. 

All fuel cells exhibit kinetic losses that cause the electrode reactions to deviate from their theoretical ideal. This is particularly true for a direct methanol PEFC. Eliminating the need for a fuel reformer, however, makes methanol and air PEFCs an attractive alternative to PEFCs that require pure hydrogen as a fuel. The minimum performance goal for direct methanol PEFC commercialization is approximately 200 mW/cm at 0.5 to 0.6 V. 

As the CH4 component of the fuel reforms to CO and H2, H2O is consumed. This favors the reversal of Equation (8-16), which allows Si02 to be deposited downstream, possibly on exposed nickel surfaces. Oxygen-blown coal gas, however, has an H2O content of only -13%, and this is not expected to allow for significant Si transport. 

Present formula gasolines contain approximately 300 ppm. No. 2 fuel oil contains 2,200 to 2,600 ppm by weight of sulfur. Even pipeline gas contains sulfur-containing odorants (mercaptans, disulfides, or commercial odorants) for leak detection. Metal catalysts in the fuel reformer can be susceptible to sulfur poisoning and it is very important that sulfur in the fuel reformate be removed. Some researchers have advised limiting the sulfur content of the fuel in a stream reformer to less than 0.1 ppm, but noted the limit may be higher in an autothermal... 

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