在用多孔性固體(ti)(ti)物質(zhi)(zhi)處(chu)理流(liu)(liu)體(ti)(ti)混合物時(shi)(shi),流(liu)(liu)體(ti)(ti)中的某一組(zu)分(fen)或某些組(zu)分(fen)可被吸(xi)表面并濃集(ji)其上,此現象稱為(wei)吸(xi)附。吸(xi)附處(chu)理廢(fei)氣(qi)時(shi)(shi),吸(xi)附的對(dui)象是氣(qi)態污染物,氣(qi)固吸(xi)附。被吸(xi)附的氣(qi)體(ti)(ti)組(zu)分(fen)稱為(wei)吸(xi)附質(zhi)(zhi),多孔固體(ti)(ti)物質(zhi)(zhi)稱為(wei)吸(xi)附劑。
吸(xi)收(shou)法采用低揮(hui)發或不揮(hui)發性溶劑對VOCs進行吸(xi)收(shou),再利用VOCs和吸(xi)收(shou)劑物理性質的(de)差異進行分(fen)離(li)。
含VOCs的氣(qi)(qi)體(ti)自吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)塔(ta)底部進(jin)入塔(ta)內(nei),在上升過程(cheng)中與來自塔(ta)頂(ding)的吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)劑(ji)逆流接觸,凈(jing)(jing)化后的氣(qi)(qi)體(ti)由塔(ta)頂(ding)排出。吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)了VOCs的吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)劑(ji)通過熱交換(huan)器(qi)(qi)后,廢氣(qi)(qi)處理設備進(jin)入汽(qi)提塔(ta)頂(ding)部,在溫(wen)度高(gao)于(yu)吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)溫(wen)度或(huo)壓(ya)力低于(yu)吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)壓(ya)力的條件下解吸(xi)(xi)(xi)。解吸(xi)(xi)(xi)后的吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)劑(ji)經過溶劑(ji)冷(leng)凝器(qi)(qi)冷(leng)凝后回(hui)到吸(xi)(xi)(xi)收(shou)(shou)(shou)(shou)塔(ta)。解吸(xi)(xi)(xi)出的VOCs氣(qi)(qi)體(ti)經過冷(leng)凝器(qi)(qi)、氣(qi)(qi)液分離器(qi)(qi)后以(yi)較純的VOCs氣(qi)(qi)體(ti)離開汽(qi)提塔(ta),被回(hui)收(shou)(shou)(shou)(shou)利用。該(gai)工藝適(shi)合于(yu)VOCs濃度較高(gao)、溫(wen)度較低的氣(qi)(qi)體(ti)凈(jing)(jing)化,其(qi)他(ta)情況下需要作(zuo)相(xiang)應的工藝調整(zheng)。
固(gu)體表面(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)了(le)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)后(hou),一(yi)部被吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)可(ke)從吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑表面(mian)脫離(li),此現附(fu)(fu)(fu)。而(er)(er)當(dang)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)進行一(yi)段時間(jian)后(hou),由(you)于表面(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)的(de)(de)濃集,使(shi)其吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)能力(li)明顯下降(jiang)而(er)(er)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)凈化的(de)(de)要求,此時需(xu)要采用(yong)一(yi)定(ding)的(de)(de)措施使(shi)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑上(shang)已吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)質(zhi)脫附(fu)(fu)(fu),以協的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)能力(li),這個過程(cheng)(cheng)稱為吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)劑的(de)(de)再(zai)生。因(yin)此在實際吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)工程(cheng)(cheng)中(zhong),正是利(li)用(yong)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)一(yi)再(zai)生一(yi)再(zai)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)(fu)的(de)(de)循環過程(cheng)(cheng),達(da)到除去廢氣(qi)中(zhong)污染物質(zhi)并回收廢氣(qi)中(zhong)有用(yong)組(zu)分(fen)。