在用多(duo)孔(kong)性固(gu)體物(wu)質處理(li)流體混合物(wu)時,流體中(zhong)的某(mou)(mou)一組分(fen)(fen)或某(mou)(mou)些(xie)組分(fen)(fen)可被(bei)吸(xi)(xi)(xi)(xi)表(biao)面并(bing)濃集其上,此現象(xiang)稱(cheng)為吸(xi)(xi)(xi)(xi)附。吸(xi)(xi)(xi)(xi)附處理(li)廢氣(qi)時,吸(xi)(xi)(xi)(xi)附的對(dui)象(xiang)是氣(qi)態污染物(wu),氣(qi)固(gu)吸(xi)(xi)(xi)(xi)附。被(bei)吸(xi)(xi)(xi)(xi)附的氣(qi)體組分(fen)(fen)稱(cheng)為吸(xi)(xi)(xi)(xi)附質,多(duo)孔(kong)固(gu)體物(wu)質稱(cheng)為吸(xi)(xi)(xi)(xi)附劑。
吸(xi)收(shou)(shou)法采用(yong)低揮發或不揮發性溶劑對VOCs進(jin)行吸(xi)收(shou)(shou),再利(li)用(yong)VOCs和(he)吸(xi)收(shou)(shou)劑物理(li)性質的(de)差異進(jin)行分離。
含(han)VOCs的氣(qi)體(ti)(ti)(ti)自吸(xi)(xi)(xi)(xi)收(shou)(shou)塔(ta)底部進(jin)入(ru)塔(ta)內(nei),在上升過(guo)程中(zhong)與來自塔(ta)頂的吸(xi)(xi)(xi)(xi)收(shou)(shou)劑逆流接觸,凈(jing)化(hua)后的氣(qi)體(ti)(ti)(ti)由(you)塔(ta)頂排出(chu)。吸(xi)(xi)(xi)(xi)收(shou)(shou)了VOCs的吸(xi)(xi)(xi)(xi)收(shou)(shou)劑通過(guo)熱交換(huan)器(qi)后,廢氣(qi)處理設備進(jin)入(ru)汽提(ti)塔(ta)頂部,在溫(wen)度高于吸(xi)(xi)(xi)(xi)收(shou)(shou)溫(wen)度或壓力低于吸(xi)(xi)(xi)(xi)收(shou)(shou)壓力的條件下解吸(xi)(xi)(xi)(xi)。解吸(xi)(xi)(xi)(xi)后的吸(xi)(xi)(xi)(xi)收(shou)(shou)劑經過(guo)溶(rong)劑冷凝器(qi)冷凝后回(hui)到(dao)吸(xi)(xi)(xi)(xi)收(shou)(shou)塔(ta)。解吸(xi)(xi)(xi)(xi)出(chu)的VOCs氣(qi)體(ti)(ti)(ti)經過(guo)冷凝器(qi)、氣(qi)液分離(li)器(qi)后以較純的VOCs氣(qi)體(ti)(ti)(ti)離(li)開汽提(ti)塔(ta),被回(hui)收(shou)(shou)利用。該工藝適合(he)于VOCs濃(nong)度較高、溫(wen)度較低的氣(qi)體(ti)(ti)(ti)凈(jing)化(hua),其他情況下需要作相(xiang)應的工藝調整。
固體(ti)表面吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)了吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質后(hou)(hou),一(yi)部被吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質可從吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)表面脫(tuo)(tuo)離,此(ci)現附(fu)(fu)(fu)(fu)。而當吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)進行一(yi)段時(shi)間后(hou)(hou),由(you)于(yu)表面吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質的(de)濃(nong)集,使其吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能力(li)(li)明顯下降而吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)凈化的(de)要求,此(ci)時(shi)需要采用(yong)一(yi)定(ding)的(de)措施使吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)上已吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質脫(tuo)(tuo)附(fu)(fu)(fu)(fu),以協的(de)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能力(li)(li),這個過(guo)程稱為吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑(ji)的(de)再生(sheng)。因此(ci)在實際吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)工程中,正是利用(yong)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)一(yi)再生(sheng)一(yi)再吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的(de)循環過(guo)程,達到除(chu)去廢氣中污染物(wu)質并回(hui)收廢氣中有用(yong)組分。