一、裝置簡(jian)介
甲(jia)醇是重要(yao)有機化(hua)(hua)工(gong)(gong)(gong)(gong)原料(liao)(liao)(liao)和優質燃(ran)料(liao)(liao)(liao),廣(guang)泛(fan)應用于精細(xi)化(hua)(hua)工(gong)(gong)(gong)(gong)、塑料(liao)(liao)(liao)、醫藥(yao)、化(hua)(hua)肥等領(ling)域。甲(jia)醇也是一(yi)種重要(yao)的(de)有機溶劑,其(qi)溶解性能優于乙醇,可(ke)用于調制(zhi)涂料(liao)(liao)(liao)。甲(jia)醇還是一(yi)種很有前景(jing)的(de)清潔能源。現代大型工(gong)(gong)(gong)(gong)業化(hua)(hua)制(zhi)甲(jia)醇的(de)生產(chan)裝置,原料(liao)(liao)(liao)氣(qi)(qi)(qi)的(de)制(zhi)取既可(ke)以煤(mei)(mei)(固體(ti))作(zuo)(zuo)原料(liao)(liao)(liao),也可(ke)以油品(液體(ti))或燃(ran)料(liao)(liao)(liao)氣(qi)(qi)(qi)(氣(qi)(qi)(qi)體(ti))作(zuo)(zuo)原料(liao)(liao)(liao)。不同的(de)原料(liao)(liao)(liao),其(qi)生產(chan)方法(fa)和生產(chan)工(gong)(gong)(gong)(gong)藝大不相同。對于我(wo)國,煤(mei)(mei)炭儲(chu)量遠大于石油、天然氣(qi)(qi)(qi)儲(chu)量,因此,這(zhe)里(li)就以煤(mei)(mei)作(zuo)(zuo)原料(liao)(liao)(liao)為(wei)例(li)進(jin)行(xing)(xing)介紹,圖2.27所(suo)示為(wei)煤(mei)(mei)化(hua)(hua)工(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)藝流程框圖。以煤(mei)(mei)為(wei)原料(liao)(liao)(liao)制(zhi)甲(jia)醇,首先是將煤(mei)(mei)進(jin)行(xing)(xing)氣(qi)(qi)(qi)化(hua)(hua),即煤(mei)(mei)氣(qi)(qi)(qi)化(hua)(hua)過程。目前,煤(mei)(mei)氣(qi)(qi)(qi)化(hua)(hua)的(de)生產(chan)工(gong)(gong)(gong)(gong)藝有多(duo)種,包括塊煤(mei)(mei)或小顆(ke)粒煤(mei)(mei)氣(qi)(qi)(qi)化(hua)(hua)工(gong)(gong)(gong)(gong)藝、粉(fen)煤(mei)(mei)氣(qi)(qi)(qi)化(hua)(hua)工(gong)(gong)(gong)(gong)藝和水煤(mei)(mei)漿氣(qi)(qi)(qi)化(hua)(hua)工(gong)(gong)(gong)(gong)藝等。其(qi)中以水煤(mei)(mei)漿氣(qi)(qi)(qi)化(hua)(hua)工(gong)(gong)(gong)(gong)藝最為(wei)成熟,這(zhe)里(li)以目前應用最多(duo)的(de)ICI低壓合成工(gong)(gong)(gong)(gong)藝為(wei)例(li)進(jin)行(xing)(xing)介紹。
二、典型(xing)甲醇裝置的工藝及特(te)點
一般(ban)情況(kuang)下,甲醇的生(sheng)產(chan)過程(cheng)主要分為(wei)造氣、變換和(he)凈(jing)化、合成、精餾(liu)四個工(gong)段。
1. 造氣
目前(qian)應用(yong)較(jiao)多的(de)(de)造氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)方法(fa)是:先將煤(mei)(mei)研(yan)磨(mo)成(cheng)(cheng)煤(mei)(mei)粉(fen),然后(hou)(hou)摻水(shui)(shui)制成(cheng)(cheng)水(shui)(shui)煤(mei)(mei)漿(jiang)。水(shui)(shui)煤(mei)(mei)漿(jiang)通(tong)過(guo)泵提(ti)升壓力,然后(hou)(hou)通(tong)過(guo)噴嘴(zui)在(zai)高(gao)速氧(yang)(yang)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)流的(de)(de)作用(yong)下噴入(ru)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)爐。氧(yang)(yang)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)和(he)霧狀水(shui)(shui)煤(mei)(mei)漿(jiang)在(zai)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)爐內受高(gao)溫的(de)(de)作用(yong),迅速經(jing)(jing)歷(li)著預熱、水(shui)(shui)分(fen)蒸(zheng)(zheng)發(fa)、煤(mei)(mei)的(de)(de)干餾(liu)、揮發(fa)物的(de)(de)裂解燃燒以及(ji)碳(tan)的(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)等一系(xi)列復雜的(de)(de)物理(li)和(he)化(hua)(hua)學(xue)過(guo)程(cheng),最(zui)后(hou)(hou)生成(cheng)(cheng)以一氧(yang)(yang)化(hua)(hua)碳(tan)、氫氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)、二氧(yang)(yang)化(hua)(hua)碳(tan)和(he)水(shui)(shui)蒸(zheng)(zheng)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)為(wei)主的(de)(de)濕煤(mei)(mei)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)。合(he)成(cheng)(cheng)氨(an)裝(zhuang)(zhuang)置(zhi)的(de)(de)原料氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(氫氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)和(he)氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi))、尿素裝(zhuang)(zhuang)置(zhi)的(de)(de)原料氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(二氧(yang)(yang)化(hua)(hua)碳(tan))等也常以煤(mei)(mei)為(wei)原料氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)獲得,只是氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)的(de)(de)條件(jian)不同(tong)。合(he)成(cheng)(cheng)氨(an)裝(zhuang)(zhuang)置(zhi)的(de)(de)煤(mei)(mei)制氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)是以獲得氫氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)為(wei)主,并在(zai)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)時(shi)通(tong)過(guo)空氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)的(de)(de)加(jia)入(ru)而帶入(ru)氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi),最(zui)終獲得氫氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)和(he)氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)呈(cheng)一定比例(li)的(de)(de)混(hun)合(he)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)體(ti)。而甲(jia)醇(chun)裝(zhuang)(zhuang)置(zhi)則以獲得一氧(yang)(yang)化(hua)(hua)碳(tan)為(wei)主,因此氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)時(shi)以添加(jia)純氧(yang)(yang)為(wei)主,以減少或避免(mian)氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)的(de)(de)存在(zai)。在(zai)合(he)成(cheng)(cheng)氨(an)裝(zhuang)(zhuang)置(zhi)一節(jie)中(zhong),沒有提(ti)及(ji)造氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)工(gong)段,是因為(wei)其(qi)造氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)工(gong)段的(de)(de)過(guo)程(cheng)與(yu)這(zhe)(zhe)里類似。典型的(de)(de)煤(mei)(mei)制氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)工(gong)藝流程(cheng)示(shi)意圖(tu)(tu)如圖(tu)(tu)2.28所(suo)示(shi)。原煤(mei)(mei)經(jing)(jing)過(guo)稱重送(song)(song)至磨(mo)煤(mei)(mei)機,磨(mo)至需要的(de)(de)顆粒后(hou)(hou)送(song)(song)至煤(mei)(mei)漿(jiang)槽(cao),與(yu)水(shui)(shui)混(hun)合(he)后(hou)(hou)即形(xing)成(cheng)(cheng)水(shui)(shui)煤(mei)(mei)漿(jiang)。水(shui)(shui)煤(mei)(mei)漿(jiang)經(jing)(jing)泵加(jia)壓后(hou)(hou)送(song)(song)往(wang)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)爐。與(yu)高(gao)壓氧(yang)(yang)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)經(jing)(jing)噴嘴(zui)混(hun)合(he)進(jin)入(ru)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)化(hua)(hua)爐反(fan)應室。洗滌器下部出來的(de)(de)黑(hei)水(shui)(shui)進(jin)固體(ti)分(fen)離(li)器,液體(ti)部分(fen)(黑(hei)水(shui)(shui))進(jin)灰水(shui)(shui)處理(li)系(xi)統。除了來自洗滌器的(de)(de)黑(hei)水(shui)(shui)外,還有其(qi)他分(fen)離(li)器等產生的(de)(de)黑(hei)水(shui)(shui),這(zhe)(zhe)些黑(hei)水(shui)(shui)也將被送(song)(song)往(wang)灰水(shui)(shui)處理(li)系(xi)統。
2. 變換和凈化
凈化工段主要(yao)包括變換(huan)(huan)和脫(tuo)(tuo)硫(liu)、脫(tuo)(tuo)碳(tan)兩部分(fen),但(dan)有(you)些裝置也包含硫(liu)回收部分(fen)。變換(huan)(huan)的(de)目的(de)是(shi)調節煤氣(qi)(qi)(qi)中(zhong)的(de)一氧(yang)(yang)化碳(tan)含量,以(yi)獲得甲醇合(he)成需(xu)要(yao)的(de)一氧(yang)(yang)化碳(tan)與(yu)(yu)氫氣(qi)(qi)(qi)的(de)比例。脫(tuo)(tuo)硫(liu)的(de)目的(de)是(shi)因為(wei)硫(liu)會導致(zhi)甲醇合(he)成的(de)催化劑中(zhong)毒。變換(huan)(huan)及凈化的(de)簡單工藝流(liu)程見圖2.29。氣(qi)(qi)(qi)化工段過來的(de)水煤氣(qi)(qi)(qi)首先進(jin)(jin)入(ru)預變換(huan)(huan)爐(lu),出爐(lu)后進(jin)(jin)入(ru)另一個變換(huan)(huan)爐(lu),變換(huan)(huan)后經過多次換(huan)(huan)熱和氣(qi)(qi)(qi)液(ye)分(fen)離后,與(yu)(yu)未變換(huan)(huan)的(de)煤氣(qi)(qi)(qi)合(he)并(bing),經熱回收、冷卻。
3. 合成(cheng)
低壓(ya)法合(he)成(cheng)(cheng)(cheng)(cheng)甲醇(chun)工藝流程(cheng)示意圖(tu)如圖(tu)2.30所示。凈(jing)化后(hou)(hou)(hou)的氣(qi)(qi)(qi)體送至聯合(he)壓(ya)縮(suo)(suo)(suo)機(ji)的合(he)成(cheng)(cheng)(cheng)(cheng)氣(qi)(qi)(qi)壓(ya)縮(suo)(suo)(suo)段(duan)壓(ya)縮(suo)(suo)(suo)后(hou)(hou)(hou),與甲醇(chun)分(fen)離(li)(li)器來(lai)的循環(huan)氣(qi)(qi)(qi)混合(he),進(jin)入循環(huan)氣(qi)(qi)(qi)壓(ya)縮(suo)(suo)(suo)段(duan)。經(jing)(jing)循環(huan)氣(qi)(qi)(qi)壓(ya)縮(suo)(suo)(suo)機(ji)升壓(ya)后(hou)(hou)(hou)送至合(he)成(cheng)(cheng)(cheng)(cheng)氣(qi)(qi)(qi)換(huan)熱器進(jin)行逐級換(huan)熱,送入合(he)成(cheng)(cheng)(cheng)(cheng)塔進(jin)行甲醇(chun)合(he)成(cheng)(cheng)(cheng)(cheng)。出塔氣(qi)(qi)(qi)經(jing)(jing)合(he)成(cheng)(cheng)(cheng)(cheng)氣(qi)(qi)(qi)換(huan)熱器回收熱量后(hou)(hou)(hou)進(jin)入水(shui)冷(leng)器,經(jing)(jing)水(shui)冷(leng)后(hou)(hou)(hou)出塔,同(tong)時生成(cheng)(cheng)(cheng)(cheng)的甲醇(chun)和水(shui),在此(ci)得以冷(leng)凝。經(jing)(jing)甲醇(chun)分(fen)離(li)(li)器分(fen)離(li)(li)液相(甲醇(chun)和水(shui))后(hou)(hou)(hou),未反應氣(qi)(qi)(qi)體返(fan)回聯合(he)壓(ya)縮(suo)(suo)(suo)機(ji),經(jing)(jing)壓(ya)縮(suo)(suo)(suo)后(hou)(hou)(hou)循環(huan)使用。為防止惰性(xing)氣(qi)(qi)(qi)體在系統(tong)中(zhong)積累,要從系統(tong)中(zhong)排出弛放氣(qi)(qi)(qi)。由(you)甲醇(chun)分(fen)離(li)(li)器分(fen)離(li)(li)出的粗甲醇(chun),減壓(ya)后(hou)(hou)(hou)進(jin)入閃蒸(zheng)槽閃蒸(zheng),以除(chu)去甲醇(chun)中(zhong)的大(da)部(bu)分(fen)溶解氣(qi)(qi)(qi),然后(hou)(hou)(hou)送至甲醇(chun)精餾工段(duan)。閃蒸(zheng)氣(qi)(qi)(qi)經(jing)(jing)壓(ya)力(li)調節后(hou)(hou)(hou)用作燃料。合(he)成(cheng)(cheng)(cheng)(cheng)反應熱通過合(he)成(cheng)(cheng)(cheng)(cheng)塔殼側的沸騰水(shui)的飽和蒸(zheng)汽帶走。
4. 精餾
在甲醇合(he)成時,因合(he)成條件及(ji)催(cui)化劑性(xing)能(neng)等(deng)因素的(de)影響,在產生甲醇反應的(de)同時,還(huan)伴隨(sui)著一(yi)系列的(de)副反應。所(suo)得產品除甲醇外,還(huan)有(you)水、醚、醛(quan)、酮(tong)、酯(zhi)、烷烴、有(you)機酸(suan)等(deng)幾十種有(you)機雜質(zhi)。所(suo)以,粗(cu)甲醇需進行精(jing)餾(liu)提(ti)純。甲醇精(jing)餾(liu)工藝流程示意圖如(ru)圖2.31所(suo)示。
粗(cu)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)經(jing)預(yu)(yu)熱(re)后(hou)入預(yu)(yu)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta),該塔(ta)(ta)(ta)主要是將二甲(jia)(jia)(jia)(jia)醚(mi)等低沸點餾(liu)(liu)分從(cong)塔(ta)(ta)(ta)頂(ding)分離。低沸點餾(liu)(liu)分不凝氣體(ti)從(cong)塔(ta)(ta)(ta)頂(ding)排出,送(song)(song)至(zhi)燃料氣系統。塔(ta)(ta)(ta)底的液體(ti)由(you)預(yu)(yu)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)塔(ta)(ta)(ta)底泵升壓(ya)(ya)(ya)(ya)后(hou)送(song)(song)入加(jia)(jia)壓(ya)(ya)(ya)(ya)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)進行蒸餾(liu)(liu)。加(jia)(jia)壓(ya)(ya)(ya)(ya)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)塔(ta)(ta)(ta)頂(ding)氣體(ti)被冷凝后(hou),一(yi)部(bu)分作為(wei)精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)加(jia)(jia)壓(ya)(ya)(ya)(ya)塔(ta)(ta)(ta)的回(hui)流,另一(yi)部(bu)分作為(wei)精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)產品送(song)(song)至(zhi)精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)儲罐。加(jia)(jia)壓(ya)(ya)(ya)(ya)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)底的精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)液體(ti),靠自(zi)身壓(ya)(ya)(ya)(ya)力送(song)(song)入常壓(ya)(ya)(ya)(ya)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)進一(yi)步精(jing)(jing)(jing)餾(liu)(liu)。常壓(ya)(ya)(ya)(ya)精(jing)(jing)(jing)餾(liu)(liu)塔(ta)(ta)(ta)頂(ding)部(bu)蒸汽經(jing)冷凝器冷凝后(hou),部(bu)分作為(wei)回(hui)流液返回(hui)塔(ta)(ta)(ta)內,部(bu)分作為(wei)精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)產品與加(jia)(jia)壓(ya)(ya)(ya)(ya)塔(ta)(ta)(ta)的精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)匯(hui)合,一(yi)起(qi)送(song)(song)至(zhi)精(jing)(jing)(jing)甲(jia)(jia)(jia)(jia)醇(chun)(chun)(chun)(chun)儲槽。
三、介質(zhi)特(te)點
甲(jia)醇(chun)裝置中包含(han)的特(te)殊介質有:甲(jia)醇(chun)、氫(qing)氣、一(yi)氧(yang)化碳、二氧(yang)化碳、高壓氧(yang)氣、黑水(shui)(shui)等。甲(jia)醇(chun)是一(yi)種透(tou)明、無色(se)、易燃、有毒的液體(ti),略帶酒精味。熔點(dian)為(wei)(wei)-97.8℃,沸點(dian)為(wei)(wei)64.8℃,自燃點(dian)為(wei)(wei)47℃,能(neng)與(yu)水(shui)(shui)、乙醇(chun)、乙醚、苯、
丙(bing)酮和大多數有機溶(rong)劑相混溶(rong),遇熱、明火(huo)或氧化劑易(yi)著火(huo)。甲(jia)醇屬于甲(jia)B類可(ke)燃液體。按(an)GB 5044 標準(zhun)甲(jia)醇屬于中度危害介質。
四、甲醇裝置的配(pei)管設(she)計(ji)
主(zhu)要是(shi)對塔(ta)、罐、泵、反應器等(deng)設備的配管設計。