Multi-Fuel Processors

Some workers and companies are also developing fuel processors suitable for a variety of fuels. If these systems were as reliable and efficient as those fuel processors that are tailor made for a specific fuel, multi-fuel processors would of course be a superior solution. 

Ethanol Gasoline Gasoline (Euro) (US) Diesel Jet Fuel Methanol 

Real-time switching between gasoline and diesel fuel could actually be demonstrated at different load levels without any apparent change to the performance of the system 621). However, low sulfur fuels were utilised exclusively. The fuel processor was tested in combination with an Andromeda fuel cell stack developed by Nuvera. No apparent difference could be observed when operating the combined system with ethanol, gasoline or diesel fuel [621]. However, recent activities of these workers have been directed towards a lOkWd on-board power plant or auxiliary power unit [621]. 

Meyer et cd. described the development of a multi-fuel processor by International Fuel Cells, LLC [627]. Methanol and gasohne (quality California reformulated gasoline grade II) were the major fuel alternatives. The technology chosen consisted of feed desulfurisation, autothermal reforming and catalytic carbon monoxide removal by two water-gas shift stages and two preferential oxidation reactors. The system had a power equivalent of 50 kW. However, performance data were only provided with respect to the autothermal reformer Desulfurisation proved to increase the reformer conversion up to 98%. No residual heavy hydrocarbons then remained in the product. The hot spot of the autothermal reformer approached 1000 °C. 

Meyer et al. also described the full range of hydrocarbon fuelled fuel cell systems that International Fuel Cells, LLC had developed by the year 2000 [627]. The fuels ranged from methane to heavy hydrocarbons and the system size from 500 W to 11 MW. The fuel cell technology, which was suppUed with hydrogen from the fuel processors, were reported to cover alkaline, proton exchange, molten carbonate and phosphoric acid fuel cells. However, no details were provided concerning the specific applications or performance of these systems. 

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Nuvera is working with the Department of Energy to develop efficient, low emission, on-board multi-fuel processors for the transportation application. The fuels include gasoline, methanol, ethanol, and natural gas. 

A substrate only multi-fuel processor has been designed and tested. Preliminary data on gasoline indicate 80% efficiency (at HTS exit). Detailed testing is expected to validate the performance projections of specific power, power density, and emissions. 

IV.C.2 Multi-fuel Processor for Fuel Cell Electric Vehicle Applications... 

Figure 7.15 Multi-fuel processor developed by Irving and Pickles for a 1 kW PEM fuel cell [80] the device contains microstructured components and membrane separation.

Jming, P.M. and Piddes, J.S. (2006) Operational requirments for a multi-fuel processor that generates hydrogen from bio- and petroleum bassed fuels. Presentation at the Fuel Cell Seminar (November 15-17), Palm Springs, California, US. 

As mentioned before, the design for methanol CPO reactors can be very simple. There has been a push in recent years towards a multi-fuel processor, brought about by the requirements of the US Department of Energy to keep open all options for fuelling vehicles. Examples of multi-fuel processors are the integrated designs of Northwest Power Systems, LLC - now known as Innovatek (Edlund and Pledger, 1998). 

Edlund D.J. and Pledger W.A. (1998) Pure hydrogen production from a multi-fuel processor . Proceedings of the US Fuel Cell Seminar, Palm Springs, CaUf., pp. 16-19. 

Catalytica Energy Systems To develop flexible-fuel processor for PEM To produce a multi-fuel processor... 

Arthur D. Little has carried out cost structure studies for a variety of fuel cell technologies for a wide range of applications, including SOFC tubular, planar and PEM technologies. Because phenomena at many levels of abstraction have a significant impact on performance and cost, they have developed a multi-level system performance and cost modeling approach (see Figure 1-15). At the most elementary level, it includes fundamental chemical reachon/reactor models for the fuel processor and fuel cell as one-dimensional systems. 

We have noted earlier that a refiner or fuel processor must live in an uncertain environment. He is subject to the vagaries of the supply of crude, the requirements of the market, and the perpetual question of the future markets for residual fuel. We have developed a processing approach—using the H-Oil process— which provides the degree of flexibility necessary to cope with this uncertain environment. A schematic flow diagram of such a multi-purpose plant is shown in Figure 8. The basic feature of this plant, which has been designed for the production of 0.3% sulfur fuel oil from various atmospheric residues, is its flexibility with respect to feedstock, product specifications, and future alternative uses of the plant. 

A 50 kW multi-fuel partial oxidation processor coupled to an SPFC stack has been presented in October 1997 by Arthur D. Little Inc., USA, and test-operated in the meantime for more than 3000 h. The fuels that can be applied are gasoline, methanol, and ethanol in a later stage, also diesel, oil, methane and propane processing will be possible [27]. In the UK, a bench-scale steam reformer system processing gasoline and diesel was successfully demonstrated for over 50 hours each. The H2 concentration in the reformate was typically... 

Reinkingh et al. from Johnson Matthqr reported on a 5-kWd HotSpot natural gas fuel processor [576]. The multi-step unit produced reformate containing 43 vol.% hydrogen, 1 vol.% methane and less than 10 ppm carbon monoxide. The reformer itself produced between only 1 and 2 vol.% carbon monoxide. The natural gas conversion exceeded 90%. 

A methane or natural gas fuel processor with 2.5-kW thermal energy output was described by Heinzel et al. [17]. It consisted of a pre-reformer, which made future multi-fuel operation possible, the reformer itself, which carried a nickel catalyst [433], it was operated between 750 and 800 ° C, and had catalytic carbon monoxide clean-up. The preferential oxidation reactor was operated at an O/CO ratio of 3.5 [433]. A carbon monoxide content of between 20 and 50 ppm could be achieved during steady state operation. An external burner suppUed the steam reforming reaction with energy. The natural gas was desulfiirised by a fixed bed of impregnated charcoal. Figure 9.21... 

Vaillant developed a multi-family home fuel cell system, along with the US company Plug Power, with an electric power output of between 1.5 and 4.5kWei. The thermal power output is in the range from 1.5 to 7.0 kWth- The system uses PEM fuel cell technology and a fuel processor and has an electrical efficiency of 35%, while the overall efficiency amounts to 85%. So far 60 fuel cell systems have already been installed for field trials. By the end of 2006 1000 000 kWh of electricity had been produced by these systems [605] (Figure 9.29). 

Figure 9.56 Multi-fuel conversion capability of the second generation fuel processor developed by Nuvera [621].

Durai-Swamy, K. and Woods, R.R. (2006) Multi-stage sulfur removal system and processor for an auxiliary fuel system. World patent WO 2006/084002. 

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