Experimental Study And Design Of Circular Flash Evaporation System By Spray

Because the production scale of cement industry is quite large, it will produce a lot of waste heat in industrial production. Waste heat power generation technology of cement kiln is a better way of industrial waste heat utilization. This kind of technology can transform the waste heat energy into the electric energy which can be used. In the process of cement production, this kind of technology can effectively reduce the energy consumption, and reduce production costs. Waste heat power generation technology by flash evaporation is a new kind of waste heat power generation technology of cement kiln. It has obvious potential in engineering applications of waste heat power generation. Flash evaporation technology can produce a lot of steam in a short period of time, with good cooling capacity. In recent years, people began to pay attention to this technology. However, due to the principle of flash evaporation technology is complex, involving phase change and gas-liquid two-phase flow, we also need further study.In this paper, we are focusing on flash evaporation technology in the field of waste heat power generation. Taking the wind of a grate cooler as waste heat source, We have designed a flash chamber and built a new type of circular flash evaporation system by spray. This system consists of the boiler heating unit, flash evaporation unit, filling water unit and data acquisition unit. For the first time, this system raise the initial temperature from 137℃ to 151℃, expand the degree of superheat from 30℃ to 42℃, increased the pressure inside the flash chamber to positive pressure and select a specially-designed swirl nozzle with two S-shaped internal vanes into the flash chamber. By means of the control variables, the influence of initial temperature, pressure, flow rate, nozzle type and the direction of spray on the mass flow rate of steam was investigated. Main work and results are as follows:(1) We have designed a flash chamber and built a new type of circular flash evaporation system by spray. What’s more, data acquisition unit required to collect a large number of experimental data.(2) Through the data analysis, it is found that filling water unit will affect the circular flash evaporation system. In order to maintain the stability of the data, the experimental data points are eliminated when that filling water unit works.(3) By means of the control variables, the influence of initial temperature, pressure, flow rate, nozzle type and the direction of spray on the mass flow rate of steam was investigated. On this basis, this experiment select nozzle type for MP1500, vertical downward spray direction as the optimal conditions of circular flash evaporation system.(4) The independent variables of the fitting formula are determined. Moreover, an empirical formula between flash efficiency and the degree of superheat is proposed based on a large amount of experimental data. The results provide reference for the flash evaporation system by spray in industrial fields.