在(zai)用多孔性固體(ti)(ti)物(wu)(wu)質處(chu)理(li)流體(ti)(ti)混合物(wu)(wu)時(shi),流體(ti)(ti)中的(de)某一組分或某些組分可(ke)被吸(xi)(xi)(xi)(xi)表面(mian)并(bing)濃集其上,此現(xian)象稱(cheng)(cheng)(cheng)為吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)。吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)處(chu)理(li)廢氣時(shi),吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)對象是氣態污染物(wu)(wu),氣固吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)。被吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)氣體(ti)(ti)組分稱(cheng)(cheng)(cheng)為吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質,多孔固體(ti)(ti)物(wu)(wu)質稱(cheng)(cheng)(cheng)為吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑。
吸(xi)收(shou)法(fa)采用低揮發或(huo)不揮發性溶劑(ji)對VOCs進行吸(xi)收(shou),再利用VOCs和(he)吸(xi)收(shou)劑(ji)物理性質的差異進行分離(li)。
含VOCs的氣(qi)體自(zi)吸(xi)(xi)(xi)收(shou)(shou)(shou)塔(ta)(ta)(ta)(ta)底部進入(ru)塔(ta)(ta)(ta)(ta)內(nei),在(zai)上升過(guo)程中與來自(zi)塔(ta)(ta)(ta)(ta)頂(ding)的吸(xi)(xi)(xi)收(shou)(shou)(shou)劑逆流接觸,凈化后的氣(qi)體由塔(ta)(ta)(ta)(ta)頂(ding)排出(chu)。吸(xi)(xi)(xi)收(shou)(shou)(shou)了(le)VOCs的吸(xi)(xi)(xi)收(shou)(shou)(shou)劑通過(guo)熱(re)交換(huan)器(qi)后,廢氣(qi)處理(li)設備進入(ru)汽提塔(ta)(ta)(ta)(ta)頂(ding)部,在(zai)溫(wen)度(du)高(gao)于吸(xi)(xi)(xi)收(shou)(shou)(shou)溫(wen)度(du)或壓(ya)(ya)力低于吸(xi)(xi)(xi)收(shou)(shou)(shou)壓(ya)(ya)力的條件下解(jie)吸(xi)(xi)(xi)。解(jie)吸(xi)(xi)(xi)后的吸(xi)(xi)(xi)收(shou)(shou)(shou)劑經過(guo)溶劑冷凝器(qi)冷凝后回到吸(xi)(xi)(xi)收(shou)(shou)(shou)塔(ta)(ta)(ta)(ta)。解(jie)吸(xi)(xi)(xi)出(chu)的VOCs氣(qi)體經過(guo)冷凝器(qi)、氣(qi)液分離(li)器(qi)后以較純的VOCs氣(qi)體離(li)開(kai)汽提塔(ta)(ta)(ta)(ta),被回收(shou)(shou)(shou)利用。該工藝(yi)適合于VOCs濃(nong)度(du)較高(gao)、溫(wen)度(du)較低的氣(qi)體凈化,其他情(qing)況下需要作(zuo)相應的工藝(yi)調(diao)整(zheng)。
固體表(biao)面(mian)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)了吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)后(hou),一(yi)部被吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)可從吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)劑表(biao)面(mian)脫離(li),此現附(fu)(fu)(fu)(fu)(fu)(fu)(fu)。而當吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)進行一(yi)段(duan)時(shi)間后(hou),由于表(biao)面(mian)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)的(de)濃集,使其吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)能(neng)力明顯下降(jiang)而吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)凈化(hua)的(de)要求,此時(shi)需要采(cai)用一(yi)定的(de)措(cuo)施使吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)劑上(shang)已吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)脫附(fu)(fu)(fu)(fu)(fu)(fu)(fu),以協的(de)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)能(neng)力,這個過(guo)程稱為吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)劑的(de)再生(sheng)。因此在實際(ji)吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)工程中,正(zheng)是(shi)利用吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)一(yi)再生(sheng)一(yi)再吸(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)(fu)的(de)循環過(guo)程,達到除去廢(fei)氣中污染物質(zhi)(zhi)并回收廢(fei)氣中有用組分(fen)。