| 摘要 |
A method and apparatus for producing liquid hydrogen in which water is electrolyzed under pressure to generate separate streams of oxygen and hydrogen. A buffer cooling circuit is provided between two streams in order that heat can be removed safely from the hydrogen product stream by direct or indirect heat exchange with an inert medium flowing in the cooling circuit. At least some of cooling and/or work required in the cooling circuit is provided by expanding the oxygen stream. Preferably, heat is exchanged between at least some of the inert medium and the low pressure oxygen stream. The invention requires only compression of the feed water so avoiding the work necessary in prior art processes to comprise feed hydrogen gas. Also, use of the high pressure oxygen to provide work and or cooling required elsewhere in the plant. As compared with conventional liquefaction processes, the economies are sufficient to enable the production, on a commercial scale, of liquid hydrogen for use as aircraft fuel to replace the usual fossil based fuels.
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