ANALYSIS LIQUEFIER CHARACTERISTICS OF LOW-PRESSURE AIR. 1. KAPITSA'S CYCLE

Abstract

The cycle of low pressure proposed by Kapitza has undergone several improvements. Despite this based on it large-tonnage air separation units (ASU) continue to be created. To him at the present time resort also at the development of ASU middle and even low capacity. We investigate the energy characteristics of Kapitsa's cycle and low-pressure cycle in which the expander work is converted into heat, be played by the environment, with oil brake or gas blowers, mechanical connection with an expander. The second cycle has a lower efficiency, while providing the same value of the coefficients of liquefaction, as a Kapitsa's cycle. Entropy analysis is carried out of losses from internal and external irreversibility. Shown that these losses are the same, under the condition support cycling of processes and closed loop. In the calculations of the characteristics the realizability of heat transfer controlled in regenerative heat exchangers for the second law of thermodynamics. Cycle characteristics were determined at a pressure of 0,1 MPa backflow and three pressures, the direct flow: 0,6; 1,0 and 1,4 MPa. Pressurization in cycles leads to an increase coefficients of liquefaction and exergy efficiency. At the same time, the value of specific exergy losses reduces in the air liquefier.