在用多孔(kong)(kong)性(xing)固體(ti)物質(zhi)處理(li)流(liu)體(ti)混(hun)合物時,流(liu)體(ti)中的(de)某一組分或(huo)某些組分可被吸(xi)表面并濃集其上,此現象稱(cheng)為(wei)(wei)吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)。吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)處理(li)廢氣(qi)時,吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)的(de)對象是氣(qi)態(tai)污(wu)染物,氣(qi)固吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)。被吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)的(de)氣(qi)體(ti)組分稱(cheng)為(wei)(wei)吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)質(zhi),多孔(kong)(kong)固體(ti)物質(zhi)稱(cheng)為(wei)(wei)吸(xi)附(fu)(fu)(fu)(fu)(fu)(fu)劑。
吸收(shou)法采用低揮發或不(bu)揮發性溶劑對VOCs進(jin)行吸收(shou),再(zai)利用VOCs和(he)吸收(shou)劑物理性質(zhi)的差異進(jin)行分離。
含VOCs的氣體(ti)(ti)自(zi)吸(xi)(xi)(xi)收(shou)(shou)塔(ta)(ta)(ta)(ta)底部進入塔(ta)(ta)(ta)(ta)內,在(zai)(zai)上升過(guo)程(cheng)中(zhong)與(yu)來自(zi)塔(ta)(ta)(ta)(ta)頂(ding)的吸(xi)(xi)(xi)收(shou)(shou)劑逆(ni)流接觸(chu),凈化后(hou)的氣體(ti)(ti)由塔(ta)(ta)(ta)(ta)頂(ding)排出。吸(xi)(xi)(xi)收(shou)(shou)了VOCs的吸(xi)(xi)(xi)收(shou)(shou)劑通過(guo)熱(re)交換器后(hou),廢氣處理(li)設備進入汽(qi)提塔(ta)(ta)(ta)(ta)頂(ding)部,在(zai)(zai)溫度高于吸(xi)(xi)(xi)收(shou)(shou)溫度或壓力低(di)于吸(xi)(xi)(xi)收(shou)(shou)壓力的條件(jian)下解吸(xi)(xi)(xi)。解吸(xi)(xi)(xi)后(hou)的吸(xi)(xi)(xi)收(shou)(shou)劑經(jing)過(guo)溶(rong)劑冷(leng)凝器冷(leng)凝后(hou)回到吸(xi)(xi)(xi)收(shou)(shou)塔(ta)(ta)(ta)(ta)。解吸(xi)(xi)(xi)出的VOCs氣體(ti)(ti)經(jing)過(guo)冷(leng)凝器、氣液分離(li)器后(hou)以(yi)較純的VOCs氣體(ti)(ti)離(li)開汽(qi)提塔(ta)(ta)(ta)(ta),被回收(shou)(shou)利用。該工(gong)藝適(shi)合于VOCs濃度較高、溫度較低(di)的氣體(ti)(ti)凈化,其他情況(kuang)下需要作相(xiang)應的工(gong)藝調整(zheng)。
固體表面吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附了吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附質(zhi)后,一(yi)部被吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附質(zhi)可從吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附劑(ji)表面脫(tuo)離,此(ci)現附。而當吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附進行(xing)一(yi)段時間(jian)后,由(you)于表面吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附質(zhi)的(de)(de)濃(nong)集,使(shi)其吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附能(neng)力明顯下(xia)降而吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附凈化(hua)的(de)(de)要求(qiu),此(ci)時需要采用(yong)一(yi)定的(de)(de)措施(shi)使(shi)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附劑(ji)上已(yi)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附質(zhi)脫(tuo)附,以協的(de)(de)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附能(neng)力,這(zhe)個過(guo)程稱(cheng)為吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附劑(ji)的(de)(de)再生(sheng)。因此(ci)在(zai)實際吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附工程中(zhong)(zhong),正是利用(yong)吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附一(yi)再生(sheng)一(yi)再吸(xi)(xi)(xi)(xi)(xi)(xi)(xi)(xi)附的(de)(de)循環(huan)過(guo)程,達(da)到除去廢氣中(zhong)(zhong)污染物質(zhi)并回(hui)收廢氣中(zhong)(zhong)有用(yong)組分。