1. A method used for the liquefaction of gases in which a highly compressed gas is cooled by expansion in an expansion engine. This is followed by further cooling in a heat exchanger, and finally cooled by the Joule–Thomson effect as it passes through an expansion valve to a lower pressure. The liquid obtained in the last expansion is withdrawn in which the remaining gas is used as the cooling medium in the heat exchanger before it is recompressed and returned to the process. The use of the expansion engine to recover some of the energy used in compressing the gas is a refinement of the earlier Linde process and also makes the liquefaction process more rapid.

2. A process for the manufacture of ammonia involving the electrolysis of water to produce hydrogen which is then burnt in air, thus converting oxygen into water and leaving nitrogen. The nitrogen and more hydrogen are then mixed, compressed to 750 bar, and passed over a catalyst at 500ºC. It is named after Georges Claude (1870–1960).