安徽煤电深度调峰下机组煤耗和污染物排放特征研究

Study on the coal consumption and pollutant discharge characteristics of coal-fired units participating in deep peak-regulating operation in Anhui Province

安徽省电源装机结构与清洁能源现状决定了燃煤火电机组参与电网深度调峰任务已成常态。以安徽省94台燃煤火电机组为研究对象,对机组深度调峰时的烟气污染物排放质量浓度、供电煤耗变化规律及调峰补偿进行分析。研究表明,安徽省煤电机组的烟气污染物排放以及供电煤耗水平已处于全国领先行列。深度调峰时因脱硝装置入口烟气温度低于催化剂最低运行温度而停止喷氨导致烟气中NO x排放质量浓度超标,可通过低温选择性催化还原(SCR)催化剂、省煤器烟气旁路、分隔烟道和分级省煤器等改造实现达标排放。不同负荷率下机组供电煤耗呈凸形曲线,且随着机组负荷率逐渐下降,机组供电煤耗率上升越显著,表明机组参与深度调峰时运行经济性明显降低。通过不同类型机组参与调峰成本增加计算、分档报价和节能减排系数公式设计,建立调峰辅助服务市场以补偿积极响应深度调峰的发电企业。

Because of the power structure of installed units and status quo of clean energy in Anhui Province,coal-fired units participate in deep peak-regulating operation regularly.Taking 94 coal-fired units as study objects,pollutant mass concentration in flue gas,variation trend of coal consumption for power supply and peak shaving compensation capacity are analyzed.The results show that the levels of pollutant emission and coal consumption for power supply of coal-fired units in Anhui Province rank on the top of China.During deep peak-regulating operations,the NO x mass concentration in flue gas may exceed standard due to the suspension of ammonia injection which results from the flue gas temperature at the denitrified inlet being lower than the minimum operating temperature of the catalyst.The problem can be solved by choosing low-temperature SCR catalyst,setting flue gas bypass for the economizer,separating the flue duct and updating the economizer in stages.The coal consumption for power supply changing with the load rate is a convex curve,and it increases more rapidly as the the load rate decreases.It indicates that the operating economy of the unit participating in the deep peak-regulating operation is significantly reduced.After calculating the added cost of peak-shaving,taking classified quotation,and setting energy-saving and emission-reduction coefficient formulas,a peak-shaving auxiliary service market is established to compensate the power generation enterprises that actively participate in deep peak-regulating operation.