Simulation and operation optimization analysis of multi-pollutant collaborative control of coal-fired flue gas based on high-temperature filtration

Abstract

Aiming at the problems that the fly ash in coal-fired power plant flue gas can easily lead to the blockage of dust collectors and air preheaters, a 410 t/h coal-fired boiler in Shanxi was taken as the research object, and a coal-fired flue gas pollution control method based on high temperature dust removal technology was proposed. The material treatment route was used to study the influence of the SCR pre-high temperature filter on the pressure drop of the flue gas treatment system process, and to determine the optimal operating parameters of each equipment. The Aspen Plus simulation software was used to build relevant models through the combination of relevant modules to simulate the flue gas treatment processes such as high temperature dust collector, SCR, ozonation, ammonia desulfurization and so on, and the technical and economic analysis was carried out. At the same time, the engineering test data were used to verify the model. The influence of equipment operation parameters on pollutant emission characteristics was studied through its sensitivity analysis function. The results show that the use of high temperature dust collector in the system can effectively alleviate the blockage problem of SCR device, significantly reduce the flow pressure drop and reduce the power consumption of induced draft fan. The SCR denitrification unit has the best denitrification efficiency at 320−350 ℃ and the ammonia nitrogen ratio of 1.0−1.1. The O3/NO value should be controlled around 1.05 when using ozone pre-oxidation. The high temperature of flue gas entering the desulfurization tower is not conducive to the absorption of SO2 in the flue gas, which leads to the reduction of desulfurization efficiency. Exergy loss of high temperature ash separated by high temperature dust remover is the main cause of exergy loss in the system, so energy utilization rate can be improved through the efficient utilization of high temperature ash heat. In this study, the model simulation results are consistent with the actual operation results, and the relative error between the simulation results and the actual operation value is less than 7%, showing a high accuracy. It provides a certain theoretical support and operation guidance for the optimization of multi-pollutant cooperative control and energy efficiency evaluation based on the high-temperature dust removal technology.

Keywords

• high-temperature precipitator
• flue gas treatment
• aspen plus
• exergy loss