使催(cui)(cui)化(hua)作用(yong)(yong)效(xiao)(xiao)率已經衰退的(de)催(cui)(cui)化(hua)劑重新恢復其效(xiao)(xiao)率的(de)過程。再生過程不涉(she)及催(cui)(cui)化(hua)劑整體(ti)結構的(de)解體(ti),僅僅是用(yong)(yong)適當(dang)的(de)方(fang)法(fa)消除那(nei)些(xie)導致(zhi)催(cui)(cui)化(hua)效(xiao)(xiao)能(neng)衰退的(de)因素。
現象介紹
例如(ru)(ru)除去(qu)存(cun)留于(yu)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)上(shang)的(de)(de)毒質、覆(fu)(fu)蓋(gai)于(yu)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)上(shang)的(de)(de)塵灰和(he)由于(yu)副反(fan)應(ying)(ying)(ying)而(er)生(sheng)(sheng)(sheng)成(cheng)于(yu)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)外表(biao)或孔隙內部(bu)的(de)(de)沉積(ji)物等,力圖恢復(fu)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)固有(you)(you)組成(cheng)和(he)構造。在(zai)(zai)有(you)(you)機催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)反(fan)應(ying)(ying)(ying)中(zhong)(zhong),由脫氫(qing)-聚合副反(fan)應(ying)(ying)(ying)生(sheng)(sheng)(sheng)成(cheng)高(gao)碳(tan)(tan)氫(qing)比的(de)(de)固體沉積(ji)物覆(fu)(fu)蓋(gai)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian),是常見的(de)(de)失活(huo)(huo)原因(yin)之一(yi)。可用通入(ru)空氣(qi)(qi)或貧氧(yang)(yang)空氣(qi)(qi)的(de)(de)方法燒(shao)去(qu)碳(tan)(tan)沉積(ji)物,使催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)再(zai)(zai)生(sheng)(sheng)(sheng);有(you)(you)些(xie)場合可用溶(rong)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)洗滌的(de)(de)方法使之再(zai)(zai)生(sheng)(sheng)(sheng)。有(you)(you)些(xie)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)作(zuo)業(ye)(ye)可在(zai)(zai)原來的(de)(de)反(fan)應(ying)(ying)(ying)器(qi)(qi)中(zhong)(zhong)進行;有(you)(you)些(xie)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)作(zuo)業(ye)(ye)條(tiao)件(如(ru)(ru)溫度)與生(sheng)(sheng)(sheng)產(chan)作(zuo)業(ye)(ye)條(tiao)件相差懸殊,必(bi)須(xu)在(zai)(zai)專門設計的(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)器(qi)(qi)中(zhong)(zhong)再(zai)(zai)生(sheng)(sheng)(sheng)。例如(ru)(ru)石油(you)裂化(hua)(hua)(hua)(hua)過(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)所用的(de)(de)鋁(lv)硅酸鹽催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)再(zai)(zai)生(sheng)(sheng)(sheng)時(shi)(shi),為構成(cheng)連(lian)續化(hua)(hua)(hua)(hua)的(de)(de)工業(ye)(ye)過(guo)程(cheng)(cheng)(cheng),可在(zai)(zai)一(yi)個流化(hua)(hua)(hua)(hua)床反(fan)應(ying)(ying)(ying)器(qi)(qi)中(zhong)(zhong)進行催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)裂化(hua)(hua)(hua)(hua),失活(huo)(huo)的(de)(de)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)連(lian)續地輸入(ru)另一(yi)流化(hua)(hua)(hua)(hua)床反(fan)應(ying)(ying)(ying)器(qi)(qi)(再(zai)(zai)生(sheng)(sheng)(sheng)器(qi)(qi))中(zhong)(zhong)再(zai)(zai)生(sheng)(sheng)(sheng),再(zai)(zai)生(sheng)(sheng)(sheng)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)連(lian)續地輸送(song)回裂化(hua)(hua)(hua)(hua)反(fan)應(ying)(ying)(ying)器(qi)(qi)。在(zai)(zai)裂化(hua)(hua)(hua)(hua)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)中(zhong)(zhong),可加入(ru)少量(liang)的(de)(de)助燃(ran)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)(如(ru)(ru)負載有(you)(you)微量(liang)鉑(bo)的(de)(de)氧(yang)(yang)化(hua)(hua)(hua)(hua)鋁(lv))以促進再(zai)(zai)生(sheng)(sheng)(sheng)過(guo)程(cheng)(cheng)(cheng),使碳(tan)(tan)沉積(ji)物的(de)(de)清除更為徹底(di)。此時(shi)(shi)排放氣(qi)(qi)中(zhong)(zhong)的(de)(de)一(yi)氧(yang)(yang)化(hua)(hua)(hua)(hua)碳(tan)(tan)幾(ji)乎可全部(bu)轉化(hua)(hua)(hua)(hua)為二氧(yang)(yang)化(hua)(hua)(hua)(hua)碳(tan)(tan),回收更多(duo)熱量(liang)。有(you)(you)些(xie)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)再(zai)(zai)生(sheng)(sheng)(sheng)過(guo)程(cheng)(cheng)(cheng)較為復(fu)雜,非貴金(jin)屬(shu)催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)上(shang)積(ji)碳(tan)(tan)時(shi)(shi),燒(shao)去(qu)碳(tan)(tan)沉積(ji)物后,多(duo)數尚需(xu)還原。鉑(bo)重(zhong)整催(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)(ji)(ji)(ji)(ji)(ji)再(zai)(zai)生(sheng)(sheng)(sheng)時(shi)(shi),在(zai)(zai)燒(shao)去(qu)碳(tan)(tan)沉積(ji)物后尚需(xu)氯化(hua)(hua)(hua)(hua)更新(xin),以提(ti)高(gao)活(huo)(huo)性金(jin)屬(shu)組分的(de)(de)分散(san)度。
反應過程
近年(nian)來,為(wei)防(fang)止環境(jing)污(wu)染,減少(shao)反應器和再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)設施(shi)投資(zi)和更好地恢復活(huo)性,特(te)別是對用(yong)于加氫、加氫裂化(hua)(hua)(hua)的(de)硫化(hua)(hua)(hua)物催(cui)(cui)化(hua)(hua)(hua)劑(ji),建立了一批(pi)催(cui)(cui)化(hua)(hua)(hua)劑(ji)再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)工(gong)廠,專(zhuan)門對催(cui)(cui)化(hua)(hua)(hua)劑(ji)進行器外(wai)再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)。可再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)的(de)催(cui)(cui)化(hua)(hua)(hua)劑(ji)經再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)處理后,實際(ji)上其組成(cheng)和結(jie)(jie)構并非(fei)能(neng)完全恢復原狀,故(gu)再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)催(cui)(cui)化(hua)(hua)(hua)劑(ji)的(de)效能(neng)一般均低于新催(cui)(cui)化(hua)(hua)(hua)劑(ji),經多次再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng)后,使用(yong)特(te)性劣化(hua)(hua)(hua)到不能(neng)維(wei)持(chi)正常作(zuo)業或(huo)催(cui)(cui)化(hua)(hua)(hua)過(guo)程的(de)經濟效益低于規定的(de)指(zhi)標,即表(biao)明(ming)催(cui)(cui)化(hua)(hua)(hua)劑(ji)壽命終止。有(you)些催(cui)(cui)化(hua)(hua)(hua)過(guo)程中(zhong)所用(yong)的(de)催(cui)(cui)化(hua)(hua)(hua)劑(ji)失效后難(nan)以(yi)再(zai)(zai)(zai)(zai)生(sheng)(sheng)(sheng),例如載體的(de)孔隙結(jie)(jie)構發生(sheng)(sheng)(sheng)改變(bian),活(huo)性成(cheng)分由于燒結(jie)(jie)而分散度嚴重下降(jiang),或(huo)與毒質作(zuo)用(yong)發生(sheng)(sheng)(sheng)難(nan)以(yi)恢復的(de)變(bian)化(hua)(hua)(hua)等。此(ci)時只能(neng)廢(fei)棄,或(huo)從中(zhong)回收(shou)某些原料,以(yi)重新制造催(cui)(cui)化(hua)(hua)(hua)劑(ji)。如加氫用(yong)的(de)鉑(bo)-氧化(hua)(hua)(hua)鋁催(cui)(cui)化(hua)(hua)(hua)劑(ji),失活(huo)后從廢(fei)催(cui)(cui)化(hua)(hua)(hua)劑(ji)回收(shou)鉑(bo)。