关键词: 机械压缩式系统, 碱液回收, 螺杆水蒸汽压缩机, 数学模拟

Abstract: Lye recovery using heat pump is beneficial in pollution control and energy saving in the industry of printing and dyeing. This paper investigated mechanical vapor recompression (MVR) system with twin-screw vapor compressor instead of Roots or centrifugal compressor to solve the problem of insufficient number of effects caused by small temperature rise in the lye recovery heat pump system. The mathematical model of every component of the system was built，the feasibility of the system’s operation conditions were evaluated，and the thermal performances of different effects of MVR systems and thermal vapor recompression (TVR) systems were simulated and calculated under the suitable operation conditions，and the economic effects of the two systems were compared. The results showed that the TVR system was not favorable when the waste lye was concentrated from 4% to 30% at 1 atm. In addition，the theoretical COP of each MVR system was over 20， and the theoretical COP and the heat exchange area increased with the increase of number of effects. The economical efficiency of the heat pump system with twin-screw vapor compressor was better than other systems in the waste lye recovery process. Applying three-effect system with twin-screw vapor compressor to lye recovery can achieve better energy saving.

Key words: MVR system, lye recovery, twin-screw vapor compressor, mathematical modeling