ARGON RECOVERY FROM AMMONIA PLANT PURGE GAS UTILIZING A COMBINATION OF CRYOGENIC AND NON-CRYOGENIC SEPARATING MEANS

摘要

An improved process is disclosed for argon recovery from an ammonia synthesis plant purge gas comprising hydrogen, nitrogen, argon, ammonia, and methane. In one embodiment of the present invention, this purge gas is subjected to the following steps: (i) Separation of ammonia at high pressure by adsorption using zeolite molecular sieve material, which is subsequently regenerated by hot purge combined with pressure reduction; (ii) Separation of methane and most of the nitrogen by pressure swing adsorption using a molecular sieve or an activated carbon material having greater selectivity for methane than argon; (iii) Separation of hydrogen for recycle to the ammonia synthesis plant using a high pressure cryogenic distillation column of a membrane separator; and (iv) Separation of the nitrogen by cryogenic distillation means to obtain essentially pure liquid argon product.