APPARATUS AND METHOD FOR LIQUEFYING NATURAL GAS BY REFRIGERATING SINGLE MIXED WORKING MEDIUM

摘要

Provided are an apparatus for liquefying natural gas by refrigerating single mixed working medium and a method thereof. The apparatus comprises a two-section compressor (1), two coolers (21, 22) connected to each section of the compressor (1) respectively, two gas-liquid separators (31, 32) connected to each cooler (21, 22) respectively , two throttle valves (51, 52) , a set of plate-fin type heat exchanger group (8) and a liquefied natural gas storage tank (9). As a result of compressing and separating the mixed cryogen in the apparatus stage by stage, the energy consumption of apparatus is reduced; and because of a multi-stage heat exchanging process, the heat exchanging curves of cold fluid and hot fluid are more cooperative, and the mixed cryogen flow is reduced effectively. Furthermore, the apparatus can adapt to run at variable loads better, and can effectively avoid liquid accumulating in the bottom of cold box.