| Fog and haze has become a lingering shadow of the winter in the north of China, which affects people's physical and mental health seriously. Coal combustion emission is the main cause of the haze. Although coal combustion pollutants emission reduction mechanism has been very mature, all kinds of measures to reduce emissions are perfect, but in the concrete implementation process are not so good. The main reason is that reduction technology research and implementation process is not fine, and the system stability is not high. The above factors cause the excess emissions of pollutants.Using CFD platform, we studied common process and system reliability problem of more than twenty power plant coal-fired boiler flue gas ultralow emissions. This article main research content is as follows. The main research content of this article is as follows.In order to improve the SCR denitration system inlet flow field uniformity of catalyst layer and the uniformity of ammonia concentration, we need to optimize the AIG upstream flue design. Based on the engineering case of CFD numerical simulation, aiming at AIG different diameter flue of different arrangement guide plate is studied, we get the optimized flue layout scheme. Aimed at different diameter flue, we set non-uniform guide plate in the inlet and outlet, add straight guide plate on upstream of different diameter flue, add straight drainage plate on downstream of different diameter flue. On the basis of above work, we determine the rated smoke gas and guide plate structure, size, location of the optimal allocation scheme.To improve the SCR denitration efficiency and prolong the service life of the catalyst, we must keep the flue gas temperature which is beneficial to the catalyst catalytic activity and distribution of smoke flow in uniform. Based on CFD numerical simulation analysis, by setting the economizer high temperature flue gas bypass, the high temperature flue gas mixed with economizer export flue gas at low temperature, make the temperature of the mixed gas to achieve optimum reaction temperature range of the catalyst. The interface form of bypass flue and the main flue is the key to high and low temperature flue gas mix. For cylindrical bypass ducting into the flue solutions, rectangular bypass ducting into the flue, venturi throat solutions, static pressure box, and other typical layout, we conducted a large number of numerical simulation research.We study from "plenum" principle, to determine the main flue outlet arrangement and the bypass flue, left and right sides of the upper contour image of "? plenum flue.In order to improve the efficiency of desulfurization, we need to optimize the traditional desulfurization system upgrade. Based on CFD numerical simulation, we optimize the design of desulfurization system and internal components. We study the slurry pool partitions device, turbulent strengthening device tower wall, increase device.These measures make the desulfurization system more efficiently. We simulated to verify internal gas-liquid two phase flow of the desulfurization tower. Numerical simulation results show that the desulfurization tower after joining spray in turbulent strengthening device, spray layer tower wall, increase device, flue gas flow deviation phenomenon disappear completely, achieve good smoke flow in uniform distribution.In order to improve the desulfurization system operation reliability, we need to set accident spray system on the entrance of desulfurization tower. Based on CFD numerical simulation, we establish the numerical simulation method of cooling water injection and droplet evaporation, turbulent mixing, heat and mass transfer process. According to the water spray cooling inside the flue temperature distribution after the simulation results, we get the nozzle, the optimal layout form.The study of the design scheme has been applied in several power plants, which run well now. The result is in the monitoring report of attachment. |
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