基于在线监测数据的燃煤电厂大气污染物达标评判方法研究

Study on Assessment of Compliance With Emission Limit Values of Air Pollutants for Coal-fired Power Plants Base on the Data From CEMS

通过收集位于东部地区的江苏、山东、广东3个具有代表性省份278台燃煤机组3个月连续在线监测数据,分别按照欧盟、美国排放标准长期平均浓度达标评判方法和中国短期小时浓度达标评判方法对179台一般机组和99台超低机组烟尘、SO2、NOx排放浓度符合限值要求情况进行了统计分析比较。研究结果显示,参考欧盟标准长期平均值(月均值)满足限值、短期平均值(日均值、小时均值)放宽的评判方法,91%以上的一般机组满足要求,95%以上的超低机组满足要求;参考美国30天滚动平均值满足限值的评判方法,所有的机组均能满足要求;如果按照小时浓度符合限值的时间比率达到100%要求作为评判标准,按月度统计,48%~70%的一般机组满足要求,69%~88%的超低机组满足要求;但如果适当降低小时浓度符合限值时间比率要求,略微降低到99%,符合要求的机组占比大幅上升,一般机组上升至77%~89%,超低机组上升至91%~95%。可见,中国要求短期小时浓度100%满足限值的评判方法明显严格于欧美,长期平均值(月平均或30天滚动平均)严格满足限值要求、适当放宽短期平均值(日或小时平均)要求的达标评判方法更符合目前中国火电行业污染治理设施运行实际状况,建议中国采用月均浓度不超过限值、小时浓度符合限值的时间比率不小于95%作为连续监测数据达标评判方法。

In order to study assessment methods compliance with emission limit of air pollutants for coal-fired power plants,on-line data of 278 coal-fired units over Jiangsu,Shandong,and Guangdong province for three months from the continuous emission monitoring system(CEMS)were collected.These data were analyzed statistically and compared based on different assessment methods.The results show that 1)according to the assessment method in Directive 2010/75/EU,more than 91%of 179 general units and more than 95%of 99 ultra-low units meet the requirement,respectively;2)according to the assessment method of 30-day rolling average in CFR40-Part60-subpartDa of US,all units can meet the requirement;3)according to the assessment method that 100%of hourly average values do not exceeds the relevant emission limit value,48%~70%of the general units and 69%~88%of the ultra-low units meet the requirements from monthly statistics data,respectively;4)while according to the assessment method that 99%of hourly average values do not exceeds the relevant emission limit value,the proportion of the units meeting the requirements increase significantly(i.e.,the general units and the ultra-low units rise to 77%~89%and 91%~95%,respectively).The assessment method that 100%of hourly average values do not exceeds the relevant emission limit value is used in China currently.It is obvious stricter than that in US and EU.(i.e.,long-term values of monthly or 30-day rolling average are forbidden to exceed the emission limit while short-term values of daily or hourly average can exceed in some certain conditions).The latter method is closer to the current situation of air pollution control in Chinese thermal power industry.Therefore,we suggest that Chinese government shall accept the assessment method that no monthly average values exceeds the relevant emission limit value and 95%of hourly average values do not exceeds the relevant emission limit value.