Method for liquefying hydrocarbon-rich fraction e.g. natural gas, involves varying refrigerant amount by removing refrigerant having temperature below critical temperature, based on load condition of refrigeration circuit

摘要

The method involves circulating the refrigerant (20) containing nitrogen methane mixture at ambient temperature in refrigerant circuit, in supercritical state. The refrigerant amount is varied by supplying or removing the refrigerant during refrigeration cycle, based on load condition of refrigeration circuit. The removal of refrigerant at refrigerant circuit is performed when refrigerant has a temperature below critical temperature, or the pressure of refrigerant is below critical pressure. The formed liquid refrigerant is stored and fed back to refrigeration circuit if required.