Mechanical steam recompression (MVR) : refers to the evaporation (distillation, etc.) process of secondary steam (low temperature, low pressure and can not be used) with the compressor compression, increase its temperature, pressure, re-as a heat source to heat the material to be evaporated, so as to achieve the purpose of recycling steam, so that the evaporation process does not need to add steam; That is, using a small amount of electric energy to obtain more thermal energy, thereby reducing the system's demand for external energy is an efficient energy-saving technology.