摘　要:闡述了(le)濕法(fa)煙氣脫(tuo)硫的(de)工藝流程與(yu)吸收原(yuan)理,分析(xi)研究脫(tuo)硫裝置的(de)運(yun)行特性,根據(ju)Ca/ S 摩爾(er)比、漿(jiang)液密(mi)度、pH 值和液/ 氣比等影(ying)響(xiang)脫(tuo)硫效(xiao)率的(de)因素(su),確(que)定了(le)維持FGD 高效(xiao)率運(yun)行時(shi)的(de)吸收塔內漿(jiang)液密(mi)度和pH值,優化(hua)了(le)漿(jiang)液循環泵和氧化(hua)風機的(de)運(yun)行方式,確(que)保了(le)FGD 高效(xiao)穩定經濟運(yun)行。

關鍵詞:濕法煙(yan)氣脫硫;脫硫效率;Ca/ S 摩爾比;液(ye)/ 氣比

中圖分類號:X773 　　文(wen)(wen)獻標識碼:B 　　文(wen)(wen)章編號(hao):100129529 (2004) 0520021203

隨著濕法煙(yan)氣(qi)脫硫(FGD) 在(zai)國內(nei)應用廠家的(de)(de)增多,確保(bao)(bao)脫硫裝(zhuang)置高(gao)效穩(wen)定(ding)(ding)運行(xing),發揮其最(zui)大社會效益是所有使用者非常關注的(de)(de)問題。本文(wen)以杭州半(ban)山(shan)發電有限(xian)公(gong)司兩臺125 MW 機組(zu)濕法煙(yan)氣(qi)脫硫裝(zhuang)置的(de)(de)運行(xing)特性為(wei)研究對象,圍繞Ca/ S摩爾比(bi)和液(ye)(ye)/ 氣(qi)比(bi)等影(ying)響脫硫效率(lv)的(de)(de)因素進(jin)行(xing)分析,尋找(zhao)最(zui)佳的(de)(de)控(kong)制點,提(ti)出(chu)了合理控(kong)制吸收塔內(nei)漿液(ye)(ye)的(de)(de)pH 值、石膏漿液(ye)(ye)的(de)(de)密度和石灰石粉的(de)(de)顆粒度,優化(hua)漿液(ye)(ye)循(xun)環泵和氧化(hua)風機的(de)(de)運行(xing)方式,加(jia)強煙(yan)氣(qi)系統(tong)和廢水(shui)系統(tong)的(de)(de)管理等保(bao)(bao)證(zheng)FGD 高(gao)效穩(wen)定(ding)(ding)運行(xing)的(de)(de)技術措施。

1 　濕法脫硫的工藝流程與吸收原理(li)

濕法脫(tuo)硫裝置(zhi)設(she)在煙氣通道(dao)中電除塵器(qi)的下游,由2 個(ge)主(zhu)系(xi)統(tong)(tong)(tong)(tong)(tong)和(he)5 個(ge)輔(fu)助系(xi)統(tong)(tong)(tong)(tong)(tong)構成。兩個(ge)主(zhu)系(xi)統(tong)(tong)(tong)(tong)(tong)是煙氣系(xi)統(tong)(tong)(tong)(tong)(tong)和(he)吸收塔系(xi)統(tong)(tong)(tong)(tong)(tong);五個(ge)輔(fu)助系(xi)統(tong)(tong)(tong)(tong)(tong)是石(shi)灰石(shi)粉的磨制、儲運(yun)及漿(jiang)液(ye)制備(bei)系(xi)統(tong)(tong)(tong)(tong)(tong),事故(gu)漿(jiang)池及漿(jiang)液(ye)疏排(pai)系(xi)統(tong)(tong)(tong)(tong)(tong),石(shi)膏脫(tuo)水儲運(yun)系(xi)統(tong)(tong)(tong)(tong)(tong),工藝(yi)水系(xi)統(tong)(tong)(tong)(tong)(tong)及廢水處理系(xi)統(tong)(tong)(tong)(tong)(tong)。濕法煙氣脫(tuo)硫主(zhu)要工藝(yi)流(liu)程(cheng)如圖1 所示。

原煙(yan)氣(qi)(qi)(qi)經(jing)FGD 的(de)(de)(de)增壓(ya)(ya)風機至(zhi)氣(qi)(qi)(qi)—氣(qi)(qi)(qi)加(jia)熱器(GGH) ,冷卻(que)后(hou)(hou)的(de)(de)(de)原煙(yan)氣(qi)(qi)(qi)隨(sui)即進入(ru)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)塔與(yu)(yu)脫硫(liu)(liu)劑接觸反應(ying),煙(yan)氣(qi)(qi)(qi)中(zhong)的(de)(de)(de)二氧化(hua)(hua)硫(liu)(liu)與(yu)(yu)漿(jiang)(jiang)液(ye)中(zhong)的(de)(de)(de)碳酸鈣以(yi)及(ji)鼓入(ru)的(de)(de)(de)氧化(hua)(hua)空氣(qi)(qi)(qi)進行(xing)化(hua)(hua)學(xue)反應(ying),最終(zhong)反應(ying)產物(wu)(wu)為石(shi)膏。經(jing)脫硫(liu)(liu)后(hou)(hou)的(de)(de)(de)凈煙(yan)氣(qi)(qi)(qi)通過(guo)(guo)(guo)除霧(wu)器,除去夾帶的(de)(de)(de)液(ye)滴,然(ran)后(hou)(hou)再返至(zhi)GGH 加(jia)熱,最后(hou)(hou)通過(guo)(guo)(guo)煙(yan)囪(cong)排(pai)出。脫硫(liu)(liu)劑石(shi)灰(hui)石(shi)粉則(ze)(ze)由(you)磨(mo)石(shi)粉廠破(po)碎磨(mo)細(xi)成(cheng)粉狀,通過(guo)(guo)(guo)制漿(jiang)(jiang)系統制成(cheng)一定濃(nong)(nong)度的(de)(de)(de)石(shi)灰(hui)石(shi)漿(jiang)(jiang)液(ye),運行(xing)時根據FGD 處(chu)理(li)的(de)(de)(de)煙(yan)氣(qi)(qi)(qi)量(liang)和(he)SO2 的(de)(de)(de)濃(nong)(nong)度,由(you)循環泵(beng)不斷地補充到(dao)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)塔內。當塔內石(shi)膏漿(jiang)(jiang)液(ye)達一定濃(nong)(nong)度后(hou)(hou)由(you)外排(pai)泵(beng)排(pai)出,經(jing)一級旋流,二級真(zhen)空皮帶脫水(shui)后(hou)(hou),得到(dao)含(han)水(shui)率低(di)于(yu)10 %的(de)(de)(de)石(shi)膏,裝車外運。濕法煙(yan)氣(qi)(qi)(qi)脫硫(liu)(liu)是由(you)物(wu)(wu)理(li)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)和(he)化(hua)(hua)學(xue)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)兩個(ge)過(guo)(guo)(guo)程(cheng)組(zu)成(cheng)的(de)(de)(de)。在(zai)物(wu)(wu)理(li)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)中(zhong)SO2溶解于(yu)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)劑中(zhong),只要氣(qi)(qi)(qi)相中(zhong)被吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)的(de)(de)(de)分(fen)(fen)壓(ya)(ya)大于(yu)液(ye)相呈(cheng)平衡時該(gai)氣(qi)(qi)(qi)體分(fen)(fen)壓(ya)(ya)時,吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)就(jiu)會進行(xing),吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)的(de)(de)(de)程(cheng)度取決于(yu)氣(qi)(qi)(qi)—液(ye)平衡,滿足亨利定律。由(you)于(yu)物(wu)(wu)理(li)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)的(de)(de)(de)推動力很小,所以(yi)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)速率較(jiao)低(di)。而化(hua)(hua)學(xue)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)使被吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)的(de)(de)(de)氣(qi)(qi)(qi)體組(zu)分(fen)(fen)與(yu)(yu)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)液(ye)的(de)(de)(de)組(zu)分(fen)(fen)發生化(hua)(hua)學(xue)反應(ying)從而有(you)效的(de)(de)(de)降低(di)了溶液(ye)表面上被吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)氣(qi)(qi)(qi)體的(de)(de)(de)分(fen)(fen)壓(ya)(ya),增加(jia)了吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)的(de)(de)(de)推動力,吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)速率較(jiao)快(kuai)。當化(hua)(hua)學(xue)反應(ying)達到(dao)平衡時,則(ze)(ze)為化(hua)(hua)學(xue)吸(xi)(xi)(xi)(xi)(xi)(xi)收(shou)(shou)(shou)(shou)(shou)(shou)(shou)過(guo)(guo)(guo)程(cheng)的(de)(de)(de)極限[4 ] 。

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