燃煤机组脱硫浆液循环泵定频运行控制策略优化及节能分析  

Control strategy optimization and energy saving analysis for slurry circulation pumps in fixed-frequency mode of desulfurization system in coal-fired power units

作　　者：高伟 刘明[1] 赵永亮[1] 王朝阳[1] 严俊杰[1] GAO Wei;LIU Ming;ZHAO Yongliang;WANG Chaoyang;YAN Junjie(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《热力发电》2024年第10期134-143,共10页Thermal Power Generation

基　　金：国家重点研发计划(2022YFB4100402)。

摘　　要：为消纳可再生能源大规模并网发电,燃煤发电机组的调峰调频任务剧增,长时间处于深度调峰和变负荷过程,导致湿法烟气脱硫系统的性能下降、厂用电率大幅上升。为此,建立了超超临界660 MW燃煤发电机组的动态模型及基于双膜理论的湿法脱硫系统动态模型;模拟了变负荷过程中不同工况点切换浆液循环泵时脱硫系统的性能,发现变负荷过程中浆液和烟气流量的精准匹配可使脱硫系统在满足SO2排放的前提下实现最小的电能消耗;进一步,获得了变负荷过程中浆液循环流量阶跃变化时SO2出口质量浓度的预测模型,提出了浆液循环泵定频运行优化控制策略,可实现变负荷过程中浆液与烟气流量的最佳匹配;最后,分析了优化控制策略的节能潜力。研究结果表明:75%THA~50%THA降负荷过程中,变负荷速率为1.0%、1.5%和2.0%Pe/min,分别可节能20.12%、21.52%和22.82%;而在升负荷过程中,分别可节能10.04%、9.90%和8.66%,变负荷过程中烟气流速变化的差异是造成降负荷和升负荷过程中节能潜力不同的根本原因。To accommodate grid-connected large-scale renewable power,coal-fired power plants need to undertake more peak shaving and frequency regulation tasks,so it will engage in the processes of deep peak shaving and load cycling for a long time.In this situation,the performance of wet flue gas desulfurization system(WFGD)will degradation and the auxiliary power consumption will increase significantly.To solve this problem,the dynamic model of an ultra-supercritical 660 MW coal-fired power unit and the dynamic model of the WFGD system based on the double-membrane theory are established.The performance of the desulfurization system is simulated when the slurry circulation pumps are switched under different operating conditions during the load cycling processes.It is found that the precise matching of slurry and flue gas during load cycling processes can achieve the minimum power consumption of the desulfurization system while meeting the SO2 emission standard.Furthermore,when the slurry circulation flowrate changes stepwise during load cycling processes,the prediction model of changes in SO2 mass concentration at the WFGD system outlet is obtained.An optimization control strategy for the slurry circulation pumps in fixed-frequency mode is proposed,which can achieve the best match between the slurry and flue gas during load cycling processes.Finally,the energy saving potential for the proposed control strategy is analyzed.When the load cycling rates are 1.0%,1.5%and 2.0%Pe/min,the energy saving potential is 20.12%,21.52%and 22.82%during loading down processes from 75%THA to 50%THA conditions,and that value will be 10.04%,9.90%and 8.66%during loading up processes,respectively.The difference in flue gas flowrate during load cycling processes is found as a key factor causing the disparate of energy saving potential during loading down and loading up processes.

关 键 词：湿法脱硫 浆液循环泵 燃煤机组 控制策略优化 节能分析 

分 类 号：TM621[电气工程—电力系统及自动化] X773[环境科学与工程—环境工程]