System and Method for Cooling Fluids Containing Hydrogen or Helium

A method for liquefying a feed stream containing hydrogen or helium comprising the steps of:

• a. mixing a hydrogen or helium refrigerant with at least one additional refrigerant component having a higher molecular weight than hydrogen or helium to form a mixed refrigerant having a molecular weight of at least 6 kg/kgmol;
• b. compressing the mixed refrigerant using a compression system that contains at least one dynamic compressor or dynamic compressor stage;
• c. separating the at least one additional refrigerant component from the hydrogen or helium refrigerant at a temperature of at least 75 K to obtain a remaining hydrogen or helium refrigerant;
• d. cooling the hydrogen or helium feed stream using the remaining hydrogen or helium refrigerant to produce a liquid hydrogen or helium product from the feed stream containing hydrogen or helium.

A system for cooling a cryogenic fluid feed stream including hydrogen or helium with a mixed refrigerant comprising:

• a. a pre-cooling heat exchanger having a pre-cool feed stream cooling passage, a low-pressure refrigerant warming passage, an intermediate-pressure refrigerant warming passage, a first refrigerant cooling passage and a second refrigerant cooling passage;
• b. a mixed gas compressor configured to receive a mixed refrigerant vapor stream from the low-pressure refrigerant warming passage;
• c. a mixed gas aftercooler in fluid communication with the mixed gas compressor;
• d. a mixing device having a first inlet in fluid communication with the mixed gas aftercooler, a second inlet and a mixing device vapor outlet, said second inlet configured to receive a mixed refrigerant vapor stream from the intermediate-pressure refrigerant warming passage;
• e. a first interstage compressor in fluid communication with the mixing device vapor outlet;
• f. a first interstage aftercooler in fluid communication with the first interstage compressor;
• g. a high-pressure accumulator in fluid communication with the first interstage aftercooler and having a high-pressure accumulator vapor outlet and a high-pressure accumulator liquid outlet, said high-pressure accumulator vapor outlet in fluid communication with the first refrigerant cooling passage and said high-pressure accumulator liquid outlet in fluid communication with the intermediate-pressure refrigerant warming passage;
• h. a first refrigerant separation device in fluid communication with the first refrigerant cooling passage and having a first refrigerant separation device liquid outlet in fluid communication with the low-pressure refrigerant warming passage and a first refrigerant separation device vapor outlet in fluid communication with the second refrigerant cooling passage;
• i. a second refrigerant separation device in fluid communication with the second refrigerant cooling passage and having a second refrigerant separation device liquid outlet in fluid communication with the low-pressure refrigerant warming passage and a second refrigerant separation device vapor outlet;
• j. a refrigerant purifier having a purifier inlet in fluid communication with the second refrigerant separation device vapor outlet and a purifier outlet where the purifier outlet is in fluid communication with the low-pressure refrigerant warming passage and the intermediate-pressure refrigerant warming passage.