在用(yong)多(duo)孔(kong)性固體(ti)物(wu)質(zhi)處(chu)理(li)流體(ti)混合(he)物(wu)時,流體(ti)中的某(mou)一組分(fen)或(huo)某(mou)些(xie)組分(fen)可被吸(xi)表(biao)面并(bing)濃集其上,此現象稱(cheng)為吸(xi)附。吸(xi)附處(chu)理(li)廢氣(qi)(qi)時,吸(xi)附的對象是氣(qi)(qi)態污染(ran)物(wu),氣(qi)(qi)固吸(xi)附。被吸(xi)附的氣(qi)(qi)體(ti)組分(fen)稱(cheng)為吸(xi)附質(zhi),多(duo)孔(kong)固體(ti)物(wu)質(zhi)稱(cheng)為吸(xi)附劑(ji)。
吸收(shou)法采用(yong)低揮發或(huo)不揮發性溶劑對VOCs進行(xing)吸收(shou),再利用(yong)VOCs和吸收(shou)劑物理性質的差異進行(xing)分離。
含(han)VOCs的氣(qi)(qi)(qi)體(ti)自吸(xi)(xi)收(shou)(shou)塔(ta)(ta)底(di)部進入(ru)塔(ta)(ta)內(nei),在上(shang)升(sheng)過(guo)程中與來自塔(ta)(ta)頂(ding)的吸(xi)(xi)收(shou)(shou)劑逆流接觸,凈(jing)(jing)化(hua)后(hou)(hou)的氣(qi)(qi)(qi)體(ti)由塔(ta)(ta)頂(ding)排出。吸(xi)(xi)收(shou)(shou)了VOCs的吸(xi)(xi)收(shou)(shou)劑通(tong)過(guo)熱(re)交換器(qi)后(hou)(hou),廢氣(qi)(qi)(qi)處理設(she)備進入(ru)汽提塔(ta)(ta)頂(ding)部,在溫度(du)高于(yu)吸(xi)(xi)收(shou)(shou)溫度(du)或壓力低(di)于(yu)吸(xi)(xi)收(shou)(shou)壓力的條件(jian)下(xia)解吸(xi)(xi)。解吸(xi)(xi)后(hou)(hou)的吸(xi)(xi)收(shou)(shou)劑經過(guo)溶(rong)劑冷凝器(qi)冷凝后(hou)(hou)回到吸(xi)(xi)收(shou)(shou)塔(ta)(ta)。解吸(xi)(xi)出的VOCs氣(qi)(qi)(qi)體(ti)經過(guo)冷凝器(qi)、氣(qi)(qi)(qi)液分離器(qi)后(hou)(hou)以較純的VOCs氣(qi)(qi)(qi)體(ti)離開汽提塔(ta)(ta),被(bei)回收(shou)(shou)利用。該工(gong)藝適合于(yu)VOCs濃度(du)較高、溫度(du)較低(di)的氣(qi)(qi)(qi)體(ti)凈(jing)(jing)化(hua),其他情況下(xia)需要作相應的工(gong)藝調整。
固體表(biao)(biao)(biao)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,一(yi)(yi)部被吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質可從吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑表(biao)(biao)(biao)面脫(tuo)離,此現附(fu)(fu)(fu)(fu)。而(er)當吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)進行一(yi)(yi)段時間(jian)后,由(you)于表(biao)(biao)(biao)面吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質的濃集,使其(qi)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能力(li)明顯下降而(er)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)凈化的要(yao)求,此時需要(yao)采(cai)用(yong)一(yi)(yi)定的措施使吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑上已(yi)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質脫(tuo)附(fu)(fu)(fu)(fu),以協(xie)的吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)能力(li),這個過程(cheng)稱為(wei)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)劑的再生(sheng)。因此在(zai)實際吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)工(gong)程(cheng)中(zhong),正是利用(yong)吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)一(yi)(yi)再生(sheng)一(yi)(yi)再吸(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)(fu)的循環過程(cheng),達(da)到除去廢氣中(zhong)污染物質并回收廢氣中(zhong)有用(yong)組分。