Heat Pump Evaporation Crystallization Technology of Salt-containing Phenol Wastewater

Abstract

China is a large country in the production and use of pesticides, and the production and use of pesticides are among the highest in the world. According to statistics, the ratio of wastewater from pesticide production to wastewater discharged is about 1:100. Arbitrary discharge of a large amount of pesticide wastewater has caused serious environmental problems. The main way of pesticide wastewater treatment is to optimize emission reduction and control emissions. At present, treatment is the main way. There are many kinds of pesticide wastewater, which need targeted treatment, greatly increasing the difficulty of treatment. This paper takes the salty waste phenol wastewater discharged from a pesticide factory as the carrier, through basic physical property analysis, thermal property detection, crystallization kinetics research, basic small test, pilot scale amplification, research and development for the evaporation of this wastewater, crystallization processing equipment. In order to optimize the process route, it is preferable to use MVR compressor technology in comparison with multi-effects. Under the conditions of evaporation temperature 75°C to 90°C, compare the parameters of compressor power, cooling water volume, total energy consumption of evaporation crystallization device, total area, etc., and determine the evaporation temperature to be 90°C. In order to improve the energy utilization rate, the heat such as condensed water, crystal slurry output, and mother liquor reflux is rationally utilized. The multi-stage plate preheater and plate evaporator are used in the equipment design. The separator and condensed water vapor-liquid separation device adopt the patented structure to improve the operation efficiency.