573liquid Hydrogen Or Fuel Reformation Fig 525

Renault and five European partners have produced a Laguna conversion with a 250 mile range using fuel-cell propulsion. The 135 cell stack produces 30 kW at a voltage of 90 V, which is transformed up to 250 V for powering the synchronous electric motor, at a 92% transformer efficiency and 90-92% motor efficiency. Nickel-metal hydride batteries are used to start up the fuel cell auxiliary systems and for braking energy regeneration. Some 8 kg of liquid hydrogen is stored in an on-board cryogenic container, (a), at -253°C to achieve the excellent range. Renault insist that an on-board reformer would emit only 15% less CO2 than an IC engine against the 50% reduction they obtain by on-board liquid hydrogen storage.

According to Arthur D. Little consultants, who have developed a petrol reforming system, a fuel-cell vehicle thus fitted can realize 80 mpg fuel economy with near zero exhaust emissions. The Cambridge subsidiary Epyx is developing the system which can also reform methanol and ethanol. It uses hybrid partial oxidation and carbon monoxide clean-up technologies to give it a claimed advantage over existing reformers. The view at (b) shows how the fuel is first vaporized (1) using waste energy from the fuel cell and vaporized fuel is burnt with a small amount of air in a partial oxidation reactor (2) which produces CO and O2. Sulphur compounds are removed from

Fig. 5.24 Ford P2000 fuel cell platform with two 35 kW Ballard stacks.
Fig. 5.25 Liquid hydrogen or reformed fuel: (a) Renault cryogenic storage; (b) Arthur D. Little reformer.

the fuel (3) and a catalytic reactor (4) is used with steam to turn the CO into H2 and CO2. The remaining CO is burnt over the catalyst (5) to reduce CO2 concentration down to 10 ppm before passing to the fuel cell (6).

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