在(zai)用(yong)多孔性固(gu)體物(wu)質(zhi)(zhi)處理流體混(hun)合(he)物(wu)時(shi),流體中的某(mou)一組(zu)(zu)分或某(mou)些組(zu)(zu)分可(ke)被吸(xi)(xi)(xi)表面(mian)并濃集其上,此現象稱(cheng)(cheng)為(wei)(wei)吸(xi)(xi)(xi)附(fu)(fu)。吸(xi)(xi)(xi)附(fu)(fu)處理廢氣(qi)時(shi),吸(xi)(xi)(xi)附(fu)(fu)的對象是氣(qi)態污染物(wu),氣(qi)固(gu)吸(xi)(xi)(xi)附(fu)(fu)。被吸(xi)(xi)(xi)附(fu)(fu)的氣(qi)體組(zu)(zu)分稱(cheng)(cheng)為(wei)(wei)吸(xi)(xi)(xi)附(fu)(fu)質(zhi)(zhi),多孔固(gu)體物(wu)質(zhi)(zhi)稱(cheng)(cheng)為(wei)(wei)吸(xi)(xi)(xi)附(fu)(fu)劑。
吸收(shou)法采用(yong)低揮發或(huo)不揮發性溶劑(ji)對(dui)VOCs進行(xing)吸收(shou),再利用(yong)VOCs和吸收(shou)劑(ji)物理(li)性質(zhi)的差異進行(xing)分離。
含(han)VOCs的(de)氣體(ti)(ti)自吸(xi)(xi)(xi)收(shou)(shou)(shou)塔(ta)底(di)部進入(ru)塔(ta)內,在(zai)上升過(guo)程中(zhong)與來(lai)自塔(ta)頂(ding)的(de)吸(xi)(xi)(xi)收(shou)(shou)(shou)劑(ji)逆(ni)流(liu)接觸,凈(jing)化后的(de)氣體(ti)(ti)由塔(ta)頂(ding)排出(chu)。吸(xi)(xi)(xi)收(shou)(shou)(shou)了VOCs的(de)吸(xi)(xi)(xi)收(shou)(shou)(shou)劑(ji)通過(guo)熱交換器后,廢氣處理設備進入(ru)汽提塔(ta)頂(ding)部,在(zai)溫(wen)(wen)度(du)高于吸(xi)(xi)(xi)收(shou)(shou)(shou)溫(wen)(wen)度(du)或壓(ya)力(li)(li)低(di)于吸(xi)(xi)(xi)收(shou)(shou)(shou)壓(ya)力(li)(li)的(de)條件(jian)下(xia)解(jie)吸(xi)(xi)(xi)。解(jie)吸(xi)(xi)(xi)后的(de)吸(xi)(xi)(xi)收(shou)(shou)(shou)劑(ji)經過(guo)溶劑(ji)冷凝器冷凝后回(hui)到吸(xi)(xi)(xi)收(shou)(shou)(shou)塔(ta)。解(jie)吸(xi)(xi)(xi)出(chu)的(de)VOCs氣體(ti)(ti)經過(guo)冷凝器、氣液(ye)分離(li)器后以較純(chun)的(de)VOCs氣體(ti)(ti)離(li)開汽提塔(ta),被回(hui)收(shou)(shou)(shou)利用。該(gai)工藝(yi)適合于VOCs濃度(du)較高、溫(wen)(wen)度(du)較低(di)的(de)氣體(ti)(ti)凈(jing)化,其他情況下(xia)需要作(zuo)相(xiang)應的(de)工藝(yi)調整。
固(gu)體表面(mian)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)了吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)(zhi)后,一部被吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)(zhi)可(ke)從(cong)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑(ji)表面(mian)脫離,此現(xian)附(fu)(fu)(fu)。而當吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)進行一段(duan)時間后,由于表面(mian)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)(zhi)的(de)濃集,使其(qi)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)能力(li)明顯下降而吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)凈化的(de)要求(qiu),此時需要采用一定的(de)措(cuo)施使吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑(ji)上已(yi)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)(zhi)脫附(fu)(fu)(fu),以協的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)能力(li),這個過(guo)程稱為吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑(ji)的(de)再(zai)生。因此在實際吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)工程中(zhong)(zhong),正是利用吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)一再(zai)生一再(zai)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)循環過(guo)程,達到除(chu)去廢(fei)氣(qi)中(zhong)(zhong)污(wu)染物(wu)質(zhi)(zhi)并回收廢(fei)氣(qi)中(zhong)(zhong)有用組(zu)分。