机械蒸汽再压缩(MVR)热泵干燥的研究进展

干燥是物料中的水分吸收足够的显热和潜热而蒸发去除的过程。水分蒸发会消耗大量的热量，同时产生大量的二次蒸汽。根据MVR热泵的高效节能原理，若将采用机械蒸汽再压缩技术提高焓值的二次蒸汽作为干燥过程的热源，则可回收二次蒸汽的全部潜热，在系统内实现水分蒸发汽化潜热与凝结潜热的互换，节能效果显著。总结了MVR热泵干燥的应用概况，阐述了过热蒸汽作为MVR热泵干燥介质的优势，以及MVR热泵干燥器的设计和选用压缩机时应考虑的问题，指出了进出料环节应尽量减少不凝气体进入干燥系统，以避免不凝气体对干燥过程冷凝换热的影响。

RESEARCH PROGRESS ON MECHANICAL VAPOR RECOMPRESSION HEAT PUMP DRYING

Drying is a process in which the moisture in the material absorbs enough sensible heat and latent heat. Moisture evaporation consumes a lot of heat, and produces a large quantity of secondary steam. According to the principle of high efficiency and energy saving of MVR heat pump,if the secondary steam whose enthalpy is increased by mechanical steam recompression technology, is used as the heat source in the drying process, all latent heat of the secondary steam can be recovered. The exchange of latent heat of evaporation and vaporization with latent heat of condensation was realized in the system, and the energy saving effect was remarkable. This paper summarized the application of MVR heat pump drying, and expounded the advantages of superheated steam as MVR heat pump drying medium, as well as the problems to be considered in the design of MVR heat pump dryer and the selection of compressor. It was pointed out that the inlet and outlet should minimize the non-condensable gas entering into the drying system, avoiding the influence of non-condensable gas on condensation heat transfer in the drying process.