在(zai)用多孔性固(gu)體物(wu)質處理流體混(hun)合物(wu)時,流體中的某一組分(fen)或某些組分(fen)可被吸(xi)(xi)表面并(bing)濃(nong)集其上,此(ci)現象稱為(wei)吸(xi)(xi)附(fu)。吸(xi)(xi)附(fu)處理廢氣(qi)(qi)時,吸(xi)(xi)附(fu)的對象是氣(qi)(qi)態(tai)污染物(wu),氣(qi)(qi)固(gu)吸(xi)(xi)附(fu)。被吸(xi)(xi)附(fu)的氣(qi)(qi)體組分(fen)稱為(wei)吸(xi)(xi)附(fu)質,多孔固(gu)體物(wu)質稱為(wei)吸(xi)(xi)附(fu)劑。
吸(xi)(xi)收(shou)法采(cai)用低揮發或不揮發性(xing)溶劑對(dui)VOCs進行(xing)吸(xi)(xi)收(shou),再利用VOCs和(he)吸(xi)(xi)收(shou)劑物(wu)理性(xing)質的(de)差異進行(xing)分(fen)離(li)。
含VOCs的(de)(de)氣(qi)(qi)體自吸(xi)收(shou)塔(ta)(ta)(ta)底部進(jin)入(ru)塔(ta)(ta)(ta)內,在上升過程中與來自塔(ta)(ta)(ta)頂的(de)(de)吸(xi)收(shou)劑(ji)逆流接觸,凈(jing)化后(hou)的(de)(de)氣(qi)(qi)體由塔(ta)(ta)(ta)頂排(pai)出。吸(xi)收(shou)了VOCs的(de)(de)吸(xi)收(shou)劑(ji)通(tong)過熱交換器(qi)后(hou),廢氣(qi)(qi)處理設備進(jin)入(ru)汽(qi)提塔(ta)(ta)(ta)頂部,在溫度(du)(du)高于吸(xi)收(shou)溫度(du)(du)或壓力(li)低于吸(xi)收(shou)壓力(li)的(de)(de)條件下解(jie)吸(xi)。解(jie)吸(xi)后(hou)的(de)(de)吸(xi)收(shou)劑(ji)經(jing)過溶劑(ji)冷(leng)凝器(qi)冷(leng)凝后(hou)回到吸(xi)收(shou)塔(ta)(ta)(ta)。解(jie)吸(xi)出的(de)(de)VOCs氣(qi)(qi)體經(jing)過冷(leng)凝器(qi)、氣(qi)(qi)液(ye)分離器(qi)后(hou)以較(jiao)純的(de)(de)VOCs氣(qi)(qi)體離開(kai)汽(qi)提塔(ta)(ta)(ta),被回收(shou)利用。該(gai)工藝適合于VOCs濃度(du)(du)較(jiao)高、溫度(du)(du)較(jiao)低的(de)(de)氣(qi)(qi)體凈(jing)化,其他(ta)情況下需要(yao)作相(xiang)應的(de)(de)工藝調整。
固體表面(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)了吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)后,一部被吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)的吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)可從吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)劑表面(mian)脫離,此現附(fu)(fu)(fu)(fu)(fu)。而(er)當吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)進行一段時間后,由于(yu)表面(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)的濃(nong)集,使(shi)其吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)能力明(ming)顯下降(jiang)而(er)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)凈化的要(yao)求,此時需要(yao)采用一定的措施使(shi)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)劑上(shang)已吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)的吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)脫附(fu)(fu)(fu)(fu)(fu),以協的吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)能力,這個過(guo)程(cheng)稱(cheng)為(wei)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)劑的再(zai)生(sheng)。因此在實際吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)工程(cheng)中(zhong)(zhong),正是(shi)利用吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)一再(zai)生(sheng)一再(zai)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)的循環(huan)過(guo)程(cheng),達(da)到除去廢(fei)氣中(zhong)(zhong)污染物質(zhi)(zhi)并(bing)回收廢(fei)氣中(zhong)(zhong)有用組(zu)分。