在(zai)用多孔(kong)性固體(ti)物(wu)質處理流(liu)體(ti)混合物(wu)時(shi),流(liu)體(ti)中的某(mou)一組(zu)分(fen)或某(mou)些組(zu)分(fen)可被吸表面(mian)并濃集(ji)其上,此現象稱(cheng)為(wei)吸附(fu)(fu)。吸附(fu)(fu)處理廢氣時(shi),吸附(fu)(fu)的對象是氣態污染物(wu),氣固吸附(fu)(fu)。被吸附(fu)(fu)的氣體(ti)組(zu)分(fen)稱(cheng)為(wei)吸附(fu)(fu)質,多孔(kong)固體(ti)物(wu)質稱(cheng)為(wei)吸附(fu)(fu)劑。
吸(xi)收(shou)法(fa)采用低揮(hui)發(fa)或不揮(hui)發(fa)性(xing)溶劑對VOCs進行(xing)吸(xi)收(shou),再利用VOCs和吸(xi)收(shou)劑物理(li)性(xing)質的差異進行(xing)分離。
含(han)VOCs的氣(qi)(qi)(qi)(qi)(qi)體自吸(xi)(xi)收(shou)(shou)(shou)塔(ta)(ta)底部(bu)進入(ru)(ru)塔(ta)(ta)內,在(zai)上升過程中與來自塔(ta)(ta)頂(ding)的吸(xi)(xi)收(shou)(shou)(shou)劑逆流接觸,凈(jing)化(hua)后(hou)的氣(qi)(qi)(qi)(qi)(qi)體由(you)塔(ta)(ta)頂(ding)排出(chu)。吸(xi)(xi)收(shou)(shou)(shou)了VOCs的吸(xi)(xi)收(shou)(shou)(shou)劑通過熱(re)交換(huan)器(qi)后(hou),廢氣(qi)(qi)(qi)(qi)(qi)處(chu)理設備進入(ru)(ru)汽提(ti)塔(ta)(ta)頂(ding)部(bu),在(zai)溫度高(gao)于吸(xi)(xi)收(shou)(shou)(shou)溫度或壓力低于吸(xi)(xi)收(shou)(shou)(shou)壓力的條件下(xia)解吸(xi)(xi)。解吸(xi)(xi)后(hou)的吸(xi)(xi)收(shou)(shou)(shou)劑經(jing)過溶劑冷(leng)凝(ning)(ning)器(qi)冷(leng)凝(ning)(ning)后(hou)回到吸(xi)(xi)收(shou)(shou)(shou)塔(ta)(ta)。解吸(xi)(xi)出(chu)的VOCs氣(qi)(qi)(qi)(qi)(qi)體經(jing)過冷(leng)凝(ning)(ning)器(qi)、氣(qi)(qi)(qi)(qi)(qi)液分離器(qi)后(hou)以較純的VOCs氣(qi)(qi)(qi)(qi)(qi)體離開汽提(ti)塔(ta)(ta),被(bei)回收(shou)(shou)(shou)利用(yong)。該工(gong)(gong)藝(yi)適合于VOCs濃(nong)度較高(gao)、溫度較低的氣(qi)(qi)(qi)(qi)(qi)體凈(jing)化(hua),其他情況(kuang)下(xia)需要作相應的工(gong)(gong)藝(yi)調(diao)整。
固體表(biao)面吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)了(le)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質(zhi)(zhi)后(hou),一(yi)(yi)部被吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質(zhi)(zhi)可從吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)表(biao)面脫(tuo)離,此(ci)現附(fu)(fu)(fu)(fu)。而當吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)進行一(yi)(yi)段(duan)時(shi)間(jian)后(hou),由于表(biao)面吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質(zhi)(zhi)的(de)(de)濃集,使其吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能(neng)力(li)明顯下降而吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)凈化的(de)(de)要求,此(ci)時(shi)需要采用一(yi)(yi)定的(de)(de)措(cuo)施使吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)上已吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質(zhi)(zhi)脫(tuo)附(fu)(fu)(fu)(fu),以協(xie)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能(neng)力(li),這個過(guo)程(cheng)(cheng)稱(cheng)為吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)的(de)(de)再(zai)生。因此(ci)在實際吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)工程(cheng)(cheng)中,正是利用吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)一(yi)(yi)再(zai)生一(yi)(yi)再(zai)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)(de)循環過(guo)程(cheng)(cheng),達到除(chu)去(qu)廢氣(qi)中污染(ran)物(wu)質(zhi)(zhi)并(bing)回收廢氣(qi)中有(you)用組分。