在用多孔性固體(ti)物(wu)(wu)質處(chu)(chu)理(li)流(liu)體(ti)混合物(wu)(wu)時(shi),流(liu)體(ti)中的(de)某(mou)一組(zu)分或某(mou)些(xie)組(zu)分可(ke)被吸(xi)(xi)(xi)表面并濃集其上,此現象稱為(wei)吸(xi)(xi)(xi)附。吸(xi)(xi)(xi)附處(chu)(chu)理(li)廢氣時(shi),吸(xi)(xi)(xi)附的(de)對象是(shi)氣態污(wu)染物(wu)(wu),氣固吸(xi)(xi)(xi)附。被吸(xi)(xi)(xi)附的(de)氣體(ti)組(zu)分稱為(wei)吸(xi)(xi)(xi)附質,多孔固體(ti)物(wu)(wu)質稱為(wei)吸(xi)(xi)(xi)附劑。
吸(xi)(xi)收(shou)法采用(yong)低揮(hui)發或不揮(hui)發性溶劑(ji)對VOCs進行吸(xi)(xi)收(shou),再利(li)用(yong)VOCs和吸(xi)(xi)收(shou)劑(ji)物(wu)理(li)性質的差異進行分離。
含VOCs的氣體(ti)(ti)自吸(xi)收(shou)(shou)(shou)(shou)塔(ta)底部進入塔(ta)內,在上升(sheng)過程中與來自塔(ta)頂的吸(xi)收(shou)(shou)(shou)(shou)劑(ji)逆流接(jie)觸,凈化后(hou)的氣體(ti)(ti)由塔(ta)頂排出(chu)。吸(xi)收(shou)(shou)(shou)(shou)了VOCs的吸(xi)收(shou)(shou)(shou)(shou)劑(ji)通過熱交換(huan)器后(hou),廢氣處(chu)理設備進入汽提塔(ta)頂部,在溫度高(gao)于(yu)(yu)吸(xi)收(shou)(shou)(shou)(shou)溫度或壓(ya)力低(di)于(yu)(yu)吸(xi)收(shou)(shou)(shou)(shou)壓(ya)力的條件下解(jie)吸(xi)。解(jie)吸(xi)后(hou)的吸(xi)收(shou)(shou)(shou)(shou)劑(ji)經過溶劑(ji)冷凝(ning)器冷凝(ning)后(hou)回到吸(xi)收(shou)(shou)(shou)(shou)塔(ta)。解(jie)吸(xi)出(chu)的VOCs氣體(ti)(ti)經過冷凝(ning)器、氣液分離(li)(li)器后(hou)以較(jiao)純的VOCs氣體(ti)(ti)離(li)(li)開汽提塔(ta),被回收(shou)(shou)(shou)(shou)利用。該工藝適合于(yu)(yu)VOCs濃度較(jiao)高(gao)、溫度較(jiao)低(di)的氣體(ti)(ti)凈化,其他(ta)情況下需(xu)要作(zuo)相應的工藝調整。
固體表面(mian)(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)了吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)質(zhi)后(hou),一(yi)(yi)(yi)部被吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)質(zhi)可從吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)劑表面(mian)(mian)脫離,此(ci)現附(fu)(fu)。而當吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)進(jin)行一(yi)(yi)(yi)段(duan)時(shi)間后(hou),由于表面(mian)(mian)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)質(zhi)的(de)(de)濃集,使其吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)能(neng)力明顯下降(jiang)而吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)凈化的(de)(de)要(yao)求,此(ci)時(shi)需要(yao)采用(yong)(yong)(yong)一(yi)(yi)(yi)定的(de)(de)措施使吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)劑上已(yi)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)質(zhi)脫附(fu)(fu),以協的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)能(neng)力,這個(ge)過程稱為吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)劑的(de)(de)再生。因此(ci)在實際(ji)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)工程中(zhong)(zhong),正是利用(yong)(yong)(yong)吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)一(yi)(yi)(yi)再生一(yi)(yi)(yi)再吸(xi)(xi)(xi)(xi)(xi)(xi)附(fu)(fu)的(de)(de)循環(huan)過程,達(da)到(dao)除去廢(fei)(fei)氣中(zhong)(zhong)污染物質(zhi)并回收廢(fei)(fei)氣中(zhong)(zhong)有用(yong)(yong)(yong)組分。