第6卷第5期過程工程學(xué)報(bào)Vol 6 No52006年10月The Chinese journal of process engineerinOct.2006煤種對(duì)煤與天然氣共氣化過程的影響歐陽(yáng)朝斌12,郭占成',段東平,宋學(xué)平12,王志1(1.中國(guó)科學(xué)院過程工程研究所,北京100080;:2.中國(guó)科學(xué)院研究生院,北京100049)摘要:以移動(dòng)床為反應(yīng)器,進(jìn)行煤與天然氣共氣化熱態(tài)模擬實(shí)驗(yàn),對(duì)無煙煤、瘦煤、肥煤與焦炭進(jìn)行了對(duì)比研究,考察了煤種在不同噴吹參數(shù)H2OCH4/O2時(shí)對(duì)高溫火焰區(qū)溫度、合成氣有效成分H2+CO和H2CO、以及CH4與水蒸汽轉(zhuǎn)化率的影響.結(jié)果表明,相對(duì)于焦炭,煤為原料時(shí),高溫火焰區(qū)溫度略高,粗合成氣有效成分H3艸CO體積含量較高,且HCO更接近于熱力學(xué)平衡值.通過不同煤種的實(shí)驗(yàn),可以直接制備H/CO在1-2之間可調(diào)、有效成分H2+CO體積含量大于92%、殘留CH4小于2%的粗合成氣,CH4轉(zhuǎn)化率超過90%,水蒸汽轉(zhuǎn)化率高達(dá)75%煤種中高灰分含量有利于煤與天然氣共氣化過程關(guān)鍵詞:煤種;天然氣;共氣化;合成氣中圖分類號(hào):TQ516文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):109-606X(2006)05-0773-04前言規(guī)模的基礎(chǔ)性研究,探討了各關(guān)鍵技術(shù)對(duì)共氣化工藝的煤與天然氣共氣化工藝是基于天然氣蒸汽轉(zhuǎn)化法影響8,在此基礎(chǔ)上以焦炭為原料進(jìn)行了產(chǎn)氣量1m3/h規(guī)模的熱態(tài)模擬實(shí)驗(yàn)研究∞.以上研究結(jié)果都證與煤氣化過程而開發(fā)的制備合成氣的新技術(shù)-,該技術(shù)以焦炭煤和天然氣為原料,以移動(dòng)床豎爐為反應(yīng)器,明了該技術(shù)的可行性及合理性.本工作以不同煤種為原可直接制備H2CO在1~2之間的合成氣.該技術(shù)相對(duì)傳料,與以焦炭為原料的熱態(tài)模擬實(shí)驗(yàn)進(jìn)行對(duì)比研究,探討煤種對(duì)該工藝的關(guān)鍵技術(shù)高溫火焰區(qū)溫度及合成統(tǒng)天然氣轉(zhuǎn)換法和煤氣化工藝來說有以下特點(diǎn):節(jié)能、氣有效成分H2+CO和H2CO、以及CH4和水蒸汽轉(zhuǎn)化產(chǎn)物中CO2含量低、合成氣中HyCO在1-2之間可調(diào)率的影響,為該工藝進(jìn)一步的工程技術(shù)研究和應(yīng)用提供及水蒸汽轉(zhuǎn)化率高.此外,該工藝也可作為一種潔凈煤技術(shù),以緩解一定時(shí)期內(nèi)我國(guó)以煤為主能源結(jié)構(gòu)帶來的基礎(chǔ).對(duì)生態(tài)和環(huán)境的影響,是一種適于我國(guó)資源特點(diǎn)的合成2熱態(tài)模擬實(shí)驗(yàn)氣制備技術(shù)Zhao等對(duì)該技術(shù)的原理進(jìn)行了詳細(xì)的探討,并應(yīng)實(shí)驗(yàn)所用原料為天然氣、工業(yè)純氧、焦炭和煤,焦用計(jì)算杋對(duì)熱力學(xué)及動(dòng)力學(xué)進(jìn)行了模擬計(jì)算.以焦炭為炭和煤的粒徑為10~20mm,天然氣、焦炭和煤的成分原料,以移動(dòng)床為反應(yīng)器,進(jìn)行了產(chǎn)氣量1m/h實(shí)驗(yàn)室如表1所示表1天然氣、煤及焦炭的組成分析結(jié)果Table I Compositions of natural gas, coke and coalsatural ga0.19Proximate analysis(%, @)Ultimate analysis (%, 0)3.6684.840.37Anthracite coal0.2328,1062831. 113.69Lean coal6768Note: 1)By difference熱態(tài)模擬實(shí)驗(yàn)爐采用爐管內(nèi)徑為200mm、長(zhǎng)1700護(hù)套管內(nèi),起始位置為O2入口( Height表示火焰區(qū)高mm的碳化硅管.用電加熱溫度補(bǔ)償,以維持氣化爐溫度),距中心軸線距瀉砳熱爐溫度為300度.高溫火焰區(qū)用6支高度相差100mm的熱電偶進(jìn)行℃,以保證O中國(guó)煤化工爐.實(shí)驗(yàn)流程如連續(xù)測(cè)溫,每2支安裝在1根外徑為8mm的Al2O3保圖1所示CNMHG收稿日期:2005-10-21,修回日期:2005-11-10基金項(xiàng)目:國(guó)家杰出青年科學(xué)基金資助項(xiàng)目(編號(hào):50225415);國(guó)家高技術(shù)研究發(fā)展計(jì)劃(863)基金資助項(xiàng)目(編號(hào):2002AA529090作者簡(jiǎn)介:歐陽(yáng)朝斌(1978-,男,湖南省漣源市人,博士研究生,化學(xué)工藝專業(yè):郭占成,通訊聯(lián)系人,Te010-62558489,E-mal: guozi@ home. ipe accn.過程工程學(xué)報(bào)第6卷在相同的實(shí)驗(yàn)條件下,考察了CH4O2=1.0時(shí),不-/Flowmet同煤種對(duì)高溫火焰區(qū)溫度的影響,結(jié)果如圖3所示.從圖可以看出,高溫火焰區(qū)溫度分布隨原料的不同而改gesturing變,溫度分布從高到低的順序?yàn)闊o煙煤>瘦煤>肥煤>焦MFC炭.因?yàn)槊涸谙到y(tǒng)升溫過程中逐漸轉(zhuǎn)變?yōu)榘虢?其結(jié)構(gòu)較焦炭疏松,在加熱過程中,焦炭的原子排列會(huì)變得越Natural ga來越規(guī)則,碳原子有序排列區(qū)域增大,這種有序化現(xiàn)象會(huì)使活性邊緣碳原子對(duì)非活性基面內(nèi)的原子數(shù)量比降低,從而使焦炭反應(yīng)活性降低!所以,半焦有利于與O3燃燒,導(dǎo)致煤在高溫火焰區(qū)溫度高于焦炭.不同煤種圖1實(shí)驗(yàn)流程示意圖Fig. I Schematic flow sheet of experimental setup生成的半焦由于存在反應(yīng)活性的差異,表1中不同煤種的灰分含量順序?yàn)闊o煙煤>瘦煤>肥煤.由于灰分中含實(shí)驗(yàn)按以下程序進(jìn)行:首先將煤(約50kg)或焦炭有Si,Ca,A,Mg,Na等氧化物,有利于提高半焦的反應(yīng)(約40kg)裝入氣化爐中,裝料高度為1700mm,檢測(cè)活性2.所以,以焦炭為原料時(shí),高溫火焰區(qū)溫度低于實(shí)驗(yàn)裝置氣密性后進(jìn)行加熱升溫.加熱爐采用三段控以煤為原料的情況,隨著煤種灰分含量的增加,高溫火溫,上段控制煤氣出口溫度為1000℃,中段和下段控焰區(qū)溫度也同時(shí)升高制管外壁溫度為1050℃,升溫時(shí)間為10h,在此過程中,煤基本上轉(zhuǎn)化為半焦.當(dāng)溫度穩(wěn)定1h后,噴入O2天然氣及水蒸汽.粗合成氣出口流量通過濕式流量計(jì)測(cè)1150量.每次改變噴吹參數(shù)后,當(dāng)爐內(nèi)測(cè)溫點(diǎn)溫度在±3℃波動(dòng)時(shí),以系統(tǒng)溫度穩(wěn)定考慮并記錄溫度,進(jìn)行連續(xù)2次采樣,用氣相色譜儀SP-3420分析各組分體積含量司105010003結(jié)果與討論9503.1煤種對(duì)高溫火焰區(qū)溫度的影響高溫火焰區(qū)溫度的控制是該工藝能否順利實(shí)施的0100200300400500關(guān)鍵技術(shù)之一,溫度不宜過高,也不宜過低根據(jù)前Flame zone height(mm)期的研究結(jié)果,采用天然氣與O2平行進(jìn)料,V=30圖3不同煤種對(duì)高溫火焰區(qū)溫度的影響L/min,H2OO2=0.17(摩爾比,下同),改變不同煤種時(shí),Fig3 Effect of coal types on the temperature in flame zone高溫火焰區(qū)溫度隨CHO增大而降低.圖2列舉了以焦3.2煤種對(duì)合成氣成分的影響炭為原料時(shí),高溫火焰區(qū)隨CH4O2的變化曲線,CH從熱力學(xué)平衡原理考慮,對(duì)于煤-氧-水蒸汽轉(zhuǎn)化絕袈解吸熱反應(yīng)是溫度降低的主要原因熱體系或天然氣-氧-水蒸汽轉(zhuǎn)化絕熱體系,當(dāng)體系的溫度和壓力一定時(shí),達(dá)到平衡所需輸入的原料量和輸出氣體組成就是一定值,即平衡自由度為0,因此合成氣成分不可調(diào):而對(duì)于煤-天然氣-氧-水蒸汽耦合轉(zhuǎn)化絕熱○1050體系,當(dāng)體系的溫度和壓力一定時(shí),平衡自由度為11000即輸入物質(zhì)的量和輸出合成氣的成分可以改變.因此在CH/O實(shí)際過程中,可以進(jìn)行多變量的調(diào)控,使合成氣H2/CO-12△-1,4在1-2之間以不同煤種與焦炭為原料,固定H2OO2=0.17及01020460my中國(guó)煤化亡成氣有效成分Flame zone height (mm)圖2高溫火焰區(qū)溫度隨CH4O2的變化曲線看出,在相同頭測(cè) CNMHG所示從表可以下,以八你料時(shí),合成氣有Fig 2 Effect of CH,/O2 ratio on the temperature in flame zone效成分H2+CO體積含量高于以焦炭為原料,而殘余CH4第5期歐陽(yáng)朝斌等:煤種對(duì)煤與天然氣共氣化過程的影響稍低,HCO更接近熱力學(xué)平衡值.主要是半焦或煤灰于熱力學(xué)平衡值:而以焦炭為原料,當(dāng)進(jìn)料中CH/O對(duì)CH4的裂解有一定的催化作用,可以提高CH4的轉(zhuǎn)化在0.8-~1.6之間時(shí),實(shí)驗(yàn)所得H2CO與熱力學(xué)平衡值相率接近,當(dāng)CH4O2在1.6-2.0之間時(shí),實(shí)驗(yàn)所得H2/CO低從表還可以看岀,以無煙煤為原料時(shí),實(shí)驗(yàn)所得于熱力學(xué)平衡值.以煤為原料時(shí),由于火焰區(qū)溫度高及H2CO與熱力學(xué)平衡值基本一致;以瘦煤為原料,當(dāng)進(jìn)半焦反應(yīng)活性高,有利于CH4的裂解,與以焦炭為原料料CH4O2在0.8-1.4之間時(shí),實(shí)驗(yàn)所得H2/CO略高于熱相比,粗合成氣有效成分更高,且H2/CO更接近熱力學(xué)力學(xué)平衡值,CH4O2在1.4~2.0之間時(shí),HyCO略低于平衡值熱力學(xué)平衡值:以肥煤為原料時(shí),實(shí)驗(yàn)所得H/CO略低表2煤種對(duì)合成氣有效成分及HCO的影響Table 2 Effects of different coal types on the active compounds and Hy/CO ratio of synthesis gas0.82001.1807601.741.73Fat coal1.281.861.96Anthracite coalLean coal96.6096.4196.5895.6996.74H2+CO(%,)Fat coal919495.2892.38Anthracite coalLean coal0.831.141.351491.6594CH4(%,q)1.33713.18Anthracite coalCO2(%,q)Lean coal1.24147Fat coal0.96l.281.383.3煤種對(duì)CH及水蒸汽轉(zhuǎn)化率的影響間時(shí),CH4轉(zhuǎn)化率在95%-90%之間.主要原因是氣體的減少CH4在粗合成氣中的含量對(duì)于煤-天然氣共氣停留時(shí)間與接觸時(shí)間有關(guān),由于CH4在氣化爐中停留時(shí)化工藝非常重要,如果CH4含量過高,合成氣有效成分間隨CH4O2增大而降低,所以帶有效能量質(zhì)子的氣體會(huì)降低,H3CO將遠(yuǎn)離熱力學(xué)平衡值,不利于下游產(chǎn)品分子的接觸時(shí)間將不足,導(dǎo)致有效碰撞減少,最后使的加工,分離CH4會(huì)增加能耗.從粗合成氣中分離CH4CH4轉(zhuǎn)化率降低.不同原料對(duì)CH4轉(zhuǎn)化率的影響大小順非常困難,所以工藝過程要盡可能地提高CH的轉(zhuǎn)化率.序?yàn)闊o煙煤>瘦煤>肥煤>焦炭.原因主要是:(1)高溫有提高水蒸汽轉(zhuǎn)化率同樣對(duì)該工藝過程有現(xiàn)實(shí)意義,可以利于CH4裂解,根據(jù)對(duì)高溫火焰區(qū)的研究可知,煤種不有效地調(diào)控高溫火焰區(qū)的溫度,水蒸汽與半焦/焦炭反應(yīng)同時(shí),氣化爐內(nèi)溫度髙低順序?yàn)闊o煙煤≯瘦煤>肥煤>焦能生成一定量的H2和CO,提高合成氣的有效成分炭;(2)半焦或煤灰對(duì)CH4裂解有一定的催化作用,所CH4和水蒸汽轉(zhuǎn)化率分別按式(1)和(2)計(jì)算,O2轉(zhuǎn)以總體上說煤有利于CH4的裂解,而不同煤種中灰分含化率以100%計(jì)量不同,造成了對(duì)CH4的催化作用不同由于氣化爐中溫度高于1000℃,當(dāng)水蒸汽噴入氣CH4轉(zhuǎn)化率(%):xCHm-CHm×100%,()化爐中,水蒸汽與部分半焦焦炭反應(yīng)生成等體積的H2和CO.移動(dòng)床煤與天然氣共氣化技術(shù)理論上水蒸汽轉(zhuǎn)水蒸汽轉(zhuǎn)化率(%):ym2m-2x。C從×100%.(2)化率接近100%,通過實(shí)驗(yàn)得到煤種對(duì)水蒸汽轉(zhuǎn)化率的影響如圖4所示.從圖可以看出,以不同煤種和焦炭為改變CH/O2時(shí),煤種對(duì)CH轉(zhuǎn)化率的影響如圖4原料時(shí)水蒸汽的轉(zhuǎn)化率在75%-85%之間,且以煤為原所示.從圖可以看出,CH4轉(zhuǎn)化率超過90%,且以煤為料時(shí)轉(zhuǎn)化率明原料時(shí),CH;轉(zhuǎn)化率高于以焦炭為原料的情況:隨著轉(zhuǎn)化率的影中國(guó)煤化不同原料對(duì)水蒸汽>肥煤>焦炭.主CHO2的增加,CH轉(zhuǎn)化率下降當(dāng)CHO2在0.8-1.6要原因也可以CNMHGI應(yīng)活性來解釋之間時(shí),CH4轉(zhuǎn)化率大于95%,當(dāng)CH4O2在1.6~20之776過程工程學(xué)報(bào)第6卷參考文獻(xiàn):98]李俊嶺,溫浩,李靜海,等.以天然氣和煤為原料的合成氣制備96方法及其制備爐P]中國(guó)專利:1418935A,2003-05-212]李俊嶺,溫浩,李靜海,等.以煤和天然氣為原料的合成氣制備爐[P]中國(guó)專利:2513997Y,2002-10-02[3] 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Recent Developments in95F(b)Steam conversion rate-O- Anthracite coalAuto-thermal Reforming and Pre-reforming for Synthesis Gas90Production in GTL Applications []. Fuel Process. Technol., 2003, 8380[4] Zhao Y H, Wen H. Guo Z C, et al. Development of a Full-flexibleCo-gasification Technology [J]. Chin. J. Chem. Eng, 2005, 13(161.82.096-101CH/O2 (% mol)5]宋學(xué)平,郭占成.移動(dòng)床煤與天然氣共氣化制備合成氣的工藝技圖4煤種對(duì)CH4和水蒸汽轉(zhuǎn)化率的影響術(shù)化工學(xué)報(bào),2005,56(2:312-317Fig 4 Effect of the coal types on the methane and steam宋學(xué)平,郭占成.固定床天然氣與煤共氣化火焰區(qū)溫度影響因素conversion rates的研究[J.燃燒化學(xué)學(xué)報(bào),2005,33(1):53-57.7]宋學(xué)平,郭占成.固定床天然氣與煤聯(lián)合氣化制合成氣反應(yīng)過程4結(jié)論的實(shí)驗(yàn)研究[J.過程工程學(xué)報(bào),2005,5(2):158-1618]SongⅹP通過以無煙煤、瘦煤、肥煤與焦炭進(jìn)行對(duì)比實(shí)驗(yàn)表Co-gasifying Coal and Natural Gas [J]. Fuel, 2005, 84: 525-531明,以煤為原料,在熱態(tài)模擬實(shí)驗(yàn)中,通過調(diào)控噴吹參歐陽(yáng)朝斌,段東平,郭占成,等天然氣煤共氣化制備合成氣熱態(tài)模擬[J.化工學(xué)報(bào),2005,5610:1436-1441數(shù)H2OCH4/O2,在氣化爐爐溫不低于1000℃的條件下[10] Ouyang ZB, Guo Z C, Duan D P, et al. Experimental Study of Coal可以直接制備出HyCO在1~2之間、有效成分H2+COGasification Coupling with Natural Gas Autothermal Reforming for體積含量大于92%、殘留CH4小于2%的粗合成氣,水Synthesis Gas Production []. Ind. Eng. Chem. Res, 2005, 44(2蒸汽轉(zhuǎn)化率超過75%,而CH4轉(zhuǎn)化率高達(dá)90%.以煤為1!]張守玉,呂俊復(fù),王文選,等.熱處理對(duì)煤焦反應(yīng)性及微觀結(jié)構(gòu)原料時(shí),由于火焰區(qū)溫度高及半焦反應(yīng)活性高,與以焦的影響門燃燒化學(xué)學(xué)報(bào),2004,32(6):673-678.炭為原料相比,粗合成氣有效成分更高,且H2CO更接12WuJH, Fang Y T, Wang Y, et al. Combined Coal Gasificat近于熱力學(xué)平衡值.高溫火焰區(qū)溫度可以通過調(diào)節(jié)Methane Reforming for Production of Syngas in FluidizReactor [J]. Energy Fuels, 2005. 19: 512-516CH/O2來控制,合成氣有效成分H2+CO及H2/CO主要[13] Huang J. Fang Y 1. Chen H S,etal. Coal Gasification依賴于噴吹參數(shù)H2OCHO2.實(shí)驗(yàn)結(jié)果還表明,隨著煤Characteristic in a Pressurized Fluidized Bed []. Energy Fuels, 2003種的灰分含量增加,其高溫火焰區(qū)溫度和生成半焦活性7:1474-1478[14] Wu J H, Fang Y T, Peng H, et al. A New Integrated Approach of都升高,合成氣有效成分H2+CO及CH4、水蒸汽轉(zhuǎn)化Coal Gasification: The Concept and Preliminary Experimenta率提高,從而使H/CO更接近于熱力學(xué)平衡值Results [J]. Fuel Process. Technol., 2004, 86: 261-266Effect of Coal Type on Coal and Natural Gas Co-gasifying ProcessOUYANG Zhao-bin, GUO Zhan-cheng, DUAN Dong-ping, SONG Xue-ping, WANG Zhi1. Inst. Process Eng, CAS, Beijing 100080, China; 2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China)Abstract: Coal and natural gas co-gasifying process is a new technology to produce synthesis gas based on natural gas steam reformingand coal gasification. A moving bed was used as the reactor in hot simulation experiments. With anthracite, lean and fat coals and cokeLs the raw materials, the effect of different coal types on the temperature in the flame zone was studied. The effect of coal type on theingredients of synthesis gas, the methane and steam conversions was investigated in the experiments. with the coals as the raw materials,the results showed that the temperature in the flame zone and the content of active compounds(H2+Co) were higher than those of cokeIn addition, the H2/CO ratio of synthesis gas was close to the value calculated by thermodynamic equilibrium For the crude synthesis gasced in this work. theds is not less than 92%o, the rudimental methane less than 2%6, and the H/coin the range of 1-2. the steam conversion rate is more than 75%0, and the methane corther ash content ofcoal is advantageous to the coal and natural gas co-gasifying process. The experimental中國(guó)煤化工 al and natural gaso-gasifying process is a new technology to produce synthesis gas suitable to the resourHCNMHGKey words: coal type; natural gas; co-gasifying; synthesis gas