干湿法SO_2排放波动对比及分析

为了考察满足超低排放条件下干法和湿法装置出口SO_2排放波动的情况,调研了国内干法装置3套、湿法装置6套,国外干法3套,并从波动的频度和幅度两个方面,按实时排放曲线、小时平均曲线、周线曲线进行了比较。归纳了影响波动的几个因素,并对循环流化床干法2种不同SO_2控制方式对出口波动影响做了分析。调研及分析的结果表明,从实时排放曲线对比看,循环流化床干法的波动频度较湿法高,但二者波动的幅度相当。从小时平均曲线对比看,波动频度二者相当,循环流化床干法的波动幅度小于湿法。与美国的干法脱硫比较结果显示,国内的循环流化床干法波动频度和幅度与国外的循环流化床干法相当。NID干法脱硫波动的幅度远大于循环流化床干法。循环流化床干法脱硫装置采用入口+出口阶梯级差比较控制方式,较前馈+反馈PID控制方式出口波动的频度高,但波动幅度较小,能够有效避免瞬时超标的现象发生。

A work has been finished for SO2 emission fluctuation analysis and comparison between DRY and WET pro- cess desulfurization, these desulfurization plants including 6 sets of dry equipment （3 sets in US and 3 sets in China） and 6 sets of WET equipment（all sets in China） Both of fluctuation-frequentness and fluctuation-range are consid- ered, according to SO2 emission curve in real time, or in one hour average, or in one week average. In conclusion, CFB-FGD is higher than WET in fluctuation-frequentness, but both of them is similar in fluctuation-range, accord- ing to SO2 emission curve in real time. CFB-FGD and WET is similar in fluctuation-frequentness, but CFB-FGD is lower than WET in fluctuation-range, according to SO2 emission cmwe in one hour average. Chinese CFB-FGD is similar than US CDS in fluctuation-frequentness and fluctuation-range. NID is more higher than CFB-FGD in fluctu- ation-rang. The differential comparison mode of SO2 emission control is higher than the feed-forward and feedback PID regulator of SO2 emission normally applied for CFB-FGD plant in fluctuation-frequentness, but the aim to be achieved to reduce the fuctuation-range of SO2 emission curve in real time. The influence factors about the fluctua- tion between DRY and WET and NID plant are to be discussed.