In the desulfurization wastewater spray evaporation treatment technology, the desulfurization wastewater generated in unit time should be completely evaporated in unit evaporation time as far as possible. Moreover, the evaporation of desulfurization wastewater has special requirements. After tiny droplets are sprayed into the flue gas flow, they need to be completely evaporated and vaporized in the shortest possible time, otherwise the incompletely vaporized droplets will corrode the flue and electrostatic precipitator. After the application of spray evaporation technology, the properties of flue gas and the characteristics of dust in flue gas will change to a certain extent, and the dust removal efficiency of flue gas dust removal is very sensitive to the characteristics of flue gas and dust in flue gas. Therefore, in spray evaporation treatment technology, the evaporation quality of droplet groups, the aerodynamic fragmentation characteristics of droplets that restrict the evaporation time of droplets, the evaporation characteristics of droplets, and the impact of spray evaporation treatment technology on flue gas dust removal will all become the key issues to be studied in spray evaporation treatment technology. At present, many fields at home and abroad have begun to involve spray evaporation technology, such as spray cooling of power exhaust system, cooling in laser surgery, spraying technology, etc. However, there is little systematic research on the key issues involved in the spray evaporation treatment technology of desulfurization wastewater tail flue. Therefore, systematic research on the factors affecting the evaporation quality of droplet groups, aerodynamic breakup of droplets, and evaporation characteristics of droplets in spray evaporation technology will enrich and promote the academic research of spray evaporation technology, and will also promote the innovation and application of spray evaporation treatment technology for wet flue gas desulfurization wastewater.
① The principle and research model of spray evaporation technology for desulfurization wastewater treatment. Through the analysis of the principle of spray evaporation technology, as well as the basic theory of key issues in spray evaporation technology, such as the mechanism of aerodynamic breakup of droplets and the mechanism of droplet evaporation, it is found that the influence of droplet deformation on the rate of droplet evaporation must be considered in the numerical study of desulfurization wastewater spray evaporation technology, and the Taylor breakup model can more truly reflect the impact of droplets in the flue gas
The deformation and fragmentation process during smoke drag. In addition, the effect of droplet internal circulation on the droplet evaporation rate is not needed to be considered in the numerical study of spray evaporation technology.
② Taking into account the boiler efficiency and the evaporation quality of the droplet group, the maximum evaporation quality of the droplet group per unit time is achieved when the flue gas temperature is 453K and the average particle size of the droplet group is 50 μ m. Aiming at the evaporation quality of droplet groups in spray evaporation treatment technology, the Euler ⁄ Lagrange discrete particle model was used to investigate for the first time the influence of key factors such as nozzle layout, injection direction, and atomization gas-liquid ratio on the evaporation quality of droplet groups. The influence of flue gas temperature and speed on the evaporation quality of droplet groups was numerically studied. It is found that the nozzle layout, spray direction and flue gas velocity in this paper have little influence on the evaporation quality of droplet group in unit time, while flue gas temperature and atomization gas-liquid ratio have great influence on the evaporation quality of droplet group in unit time. Higher flue gas temperature and larger average particle size of droplet group are conducive to the realization of spray evaporation technology for desulfurization wastewater.
③ The aerodynamic fragmentation of droplets with a particle size of 0.3mm to 0.4mm helps to shorten the complete evaporation time of the droplets. Aiming at the mechanism and characteristics of droplet pneumatic fragmentation in spray evaporation treatment technology, the Euler/Euler fluid volume model was used to numerically study the mechanism of single droplet pneumatic fragmentation and multi droplet collision fragmentation, the effects of flue gas velocity and density, droplet diameter and initial velocity on the characteristics of droplet pneumatic fragmentation, and the impact of multi droplet collision on droplet fragmentation
The impact of fragmented time. It is found that for the smoke environment and droplets studied in the spray evaporation treatment technology in this paper, there are two types of droplet breakup: bag breakup and no breakup. The aerodynamic breakup of droplets with a particle size of 0.3mm~0.4mm helps to shorten the complete evaporation time of droplets. In addition, collisions between droplets can also appropriately shorten the complete evaporation time of droplets.
④ When the physical properties of the droplet are neutral and the particle size is not greater than 50 μ m, the droplet can completely evaporate within 1 second. Aiming at the droplet evaporation characteristics in spray evaporation treatment technology, a mathematical model of droplet movement and evaporation in flue gas with the change of droplet physical properties was established
The impact. Research has found that when the smoke environment, droplet size, and initial velocity are the same, neutral droplets have the shortest complete evaporation time compared to alkaline droplets, followed by acidic droplets. The flue gas temperature has a great influence on the droplet evaporation characteristics, and properly increasing the flue gas temperature is conducive to the realization of spray evaporation technology. The flue gas velocity and initial droplet velocity have little influence on spray evaporation technology.
⑤ The spray evaporation treatment technology is conducive to improving the dust removal efficiency of flue gas. After the application of spray evaporation technology, the appropriate increase of flue gas humidity and the appropriate decrease of flue gas temperature reduce the specific resistance of ash in the flue gas, which can improve the efficiency of the dust collector. In addition, after the application of spray evaporation technology, the dust particle size in the flue gas increases. Without considering the re flying of captured dust, the increase of dust particle size also improves the dust removal efficiency. Therefore, spray evaporation treatment technology
To a certain extent, it has improved the dust removal efficiency of flue gas
