在用多(duo)孔性固體(ti)(ti)物(wu)(wu)質(zhi)處(chu)(chu)理流體(ti)(ti)混(hun)合物(wu)(wu)時,流體(ti)(ti)中的某一組分(fen)或某些組分(fen)可被(bei)吸(xi)表(biao)面并濃集其上,此現象稱(cheng)為(wei)吸(xi)附。吸(xi)附處(chu)(chu)理廢氣(qi)時,吸(xi)附的對象是(shi)氣(qi)態污染(ran)物(wu)(wu),氣(qi)固吸(xi)附。被(bei)吸(xi)附的氣(qi)體(ti)(ti)組分(fen)稱(cheng)為(wei)吸(xi)附質(zhi),多(duo)孔固體(ti)(ti)物(wu)(wu)質(zhi)稱(cheng)為(wei)吸(xi)附劑。
吸(xi)(xi)收(shou)(shou)法采用(yong)(yong)低揮(hui)發或不(bu)揮(hui)發性溶劑(ji)對VOCs進行吸(xi)(xi)收(shou)(shou),再利用(yong)(yong)VOCs和吸(xi)(xi)收(shou)(shou)劑(ji)物(wu)理性質的差異進行分(fen)離。
含VOCs的(de)氣體(ti)(ti)自吸(xi)收(shou)(shou)(shou)塔(ta)(ta)底部進入塔(ta)(ta)內,在上(shang)升過(guo)程中與來自塔(ta)(ta)頂(ding)的(de)吸(xi)收(shou)(shou)(shou)劑逆流接觸,凈化后的(de)氣體(ti)(ti)由塔(ta)(ta)頂(ding)排出。吸(xi)收(shou)(shou)(shou)了(le)VOCs的(de)吸(xi)收(shou)(shou)(shou)劑通過(guo)熱交(jiao)換器后,廢氣處(chu)理設備進入汽提(ti)塔(ta)(ta)頂(ding)部,在溫(wen)(wen)度(du)(du)(du)高于吸(xi)收(shou)(shou)(shou)溫(wen)(wen)度(du)(du)(du)或壓力低(di)于吸(xi)收(shou)(shou)(shou)壓力的(de)條件下解吸(xi)。解吸(xi)后的(de)吸(xi)收(shou)(shou)(shou)劑經(jing)過(guo)溶劑冷凝(ning)(ning)器冷凝(ning)(ning)后回到吸(xi)收(shou)(shou)(shou)塔(ta)(ta)。解吸(xi)出的(de)VOCs氣體(ti)(ti)經(jing)過(guo)冷凝(ning)(ning)器、氣液(ye)分離(li)器后以較純的(de)VOCs氣體(ti)(ti)離(li)開汽提(ti)塔(ta)(ta),被(bei)回收(shou)(shou)(shou)利用(yong)。該工藝適合于VOCs濃度(du)(du)(du)較高、溫(wen)(wen)度(du)(du)(du)較低(di)的(de)氣體(ti)(ti)凈化,其他情況下需(xu)要作相應的(de)工藝調整。
固體表(biao)面(mian)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)了吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)后,一(yi)部被吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)可從吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)劑表(biao)面(mian)脫離,此現附(fu)(fu)(fu)(fu)(fu)(fu)。而當吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)進行一(yi)段時(shi)間(jian)后,由于表(biao)面(mian)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)的(de)(de)濃集,使(shi)其吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)能力(li)明顯下降(jiang)而吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)凈化的(de)(de)要求,此時(shi)需要采(cai)用一(yi)定的(de)(de)措(cuo)施(shi)使(shi)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)劑上已吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)質(zhi)(zhi)脫附(fu)(fu)(fu)(fu)(fu)(fu),以協的(de)(de)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)能力(li),這(zhe)個過程(cheng)稱為(wei)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)劑的(de)(de)再(zai)生(sheng)。因此在實際吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)工程(cheng)中(zhong)(zhong),正是利用吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)一(yi)再(zai)生(sheng)一(yi)再(zai)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)(fu)(fu)的(de)(de)循環(huan)過程(cheng),達到除(chu)去(qu)廢氣中(zhong)(zhong)污染物質(zhi)(zhi)并回(hui)收廢氣中(zhong)(zhong)有(you)用組分。