基于高温除尘的燃煤烟气多污染物协同控制模拟及运行优化

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

针对燃煤电厂烟气中飞灰易导致除尘器、空气预热器产生堵塞等问题,以山西某410 t/h燃煤锅炉为研究对象,提出一种基于高温除尘技术的燃煤烟气污染物处理路线,研究SCR前置高温除尘器对烟气处理系统流程的压降影响,确定各设备的最佳运行参数。利用Aspen Plus模拟软件,通过相关模块的组合搭建构建相关模型对烟气流经高温除尘器、SCR、臭氧氧化、氨法脱硫等烟气处理工艺进行模拟并进行技术经济性分析,同时利用工程试验数据对模型进行验证,通过灵敏度分析功能研究设备运行参数对污染物排放特性的影响。研究结果表明:系统中采用高温除尘器能够有效缓解SCR装置堵塞问题,显著降低流程压降、减少引风机功耗;SCR脱硝装置在320~350℃、氨氮摩尔比在1.0~1.1模拟运行时脱硝效率最佳;采用臭氧前置氧化时应控制O_(3)/NO摩尔比在1.05左右;进入脱硫塔的烟气温度过高不利于烟气中SO_(2)的吸收,进而导致脱硫效率降低;高温除尘器分离的高温灰热量损失是系统中[火用]损的主要原因,因此通过高温灰热量的高效利用可提高能源利用率。模型模拟结果与实际运行结果相吻合,两者相对误差<7%,准确度较高,为基于高温除尘技术的多污染物协同控制优化和能效评价提供理论支持和运行指导。

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 influ-ence 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 block-age 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 ra-tio of 1.0−1.1. The O_(3)/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 SO_(2) 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.