本文關(guān)鍵詞：一步法煤制天然氣催化劑設(shè)計(jì)及工藝研究　出處：《青島科技大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

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【摘要】：能源是社會(huì)經(jīng)濟(jì)發(fā)展的基礎(chǔ),鑒于我國(guó)富煤貧氣的基本國(guó)情,大力發(fā)展清潔煤技術(shù)是實(shí)現(xiàn)我國(guó)能源安全的重要保證。一步法煤制天然氣技術(shù)是指在催化劑的作用下,煤粉顆粒與通入的水蒸氣發(fā)生反應(yīng),實(shí)現(xiàn)在一個(gè)反應(yīng)器中同時(shí)發(fā)生煤氣化和甲烷化反應(yīng)生成天然氣的技術(shù)。在該技術(shù)中甲烷化反應(yīng)釋放的熱量可為煤氣化反應(yīng)提供部分所需熱量,從而降低能耗。與傳統(tǒng)的煤氣化轉(zhuǎn)化技術(shù)(兩步法)相比,一步法煤制天然氣技術(shù)設(shè)備少,投資小,能耗低,因此成為新的研究熱點(diǎn)。本文利用固定床反應(yīng)器對(duì)制備的一步法煤制天然氣催化劑進(jìn)行了研究,詳細(xì)的考察了工藝參數(shù)對(duì)反應(yīng)的影響,并建立了動(dòng)力學(xué)模型,最后對(duì)催化劑的回收和工藝改進(jìn)做了初步探究,具體工作如下：1、采用浸漬法制備了K-Ni復(fù)合催化劑,在固定床反應(yīng)器中,考察了不同活性組分含量的催化劑的催化性能以及煤種對(duì)催化劑性能的影響。實(shí)驗(yàn)結(jié)果表明K-Ni復(fù)合催化劑中活性組分K和Ni具有協(xié)同效應(yīng),可生成具有高活性的K2Ni02和K3M2O4使反應(yīng)速率加快；當(dāng)K：Ni=2：1時(shí),其催化效果是單組份K2SO4的2-3倍；引入CaO可有效吸收反應(yīng)生成的CO2,促進(jìn)反應(yīng)向生成CH4的方向進(jìn)行；在K:Ni:C=2:1:1.5時(shí),甲烷含量較未加CaO均提高40%左右。2、考察了溫度、壓力、催化劑負(fù)載量和初始水碳比等工藝參數(shù)對(duì)反應(yīng)的影響,并確定了最佳工藝條件。結(jié)果表明：升高溫度可使碳轉(zhuǎn)化率明顯增加,低于700℃時(shí),甲烷化反應(yīng)未達(dá)到平衡,氣體生成受動(dòng)力學(xué)控制,適宜的反應(yīng)溫度為600-700℃：升高壓力對(duì)CH4產(chǎn)率促進(jìn)明顯,合適的反應(yīng)壓力為2.0 MPa；碳轉(zhuǎn)化率隨著H2O流量增加而增加,在初始水碳比達(dá)到1：1時(shí),顆粒表面水蒸氣接近飽和,繼續(xù)增大水碳比,碳轉(zhuǎn)率增加緩慢,而CH4產(chǎn)率呈先增大后減小的趨勢(shì),在水碳比為1.0附近存在最大值。添加催化劑可明顯提高CH4產(chǎn)量,K-Ni二元復(fù)合催化劑的負(fù)載飽和度為10%。3、采用三種動(dòng)力學(xué)模型(均相反應(yīng)模型,縮核模型及修正隨機(jī)孔模型)對(duì)煤-水蒸氣催化氣化動(dòng)力學(xué)曲線(xiàn)進(jìn)行擬合,擬合結(jié)果表明,修正隨機(jī)孔模型效果最好。采用K-Ni-Ca三元復(fù)合催化劑可使神木煤焦顆粒的活化能下降101.88kJ·mol-1,使氣化反應(yīng)在更溫和的條件下快速進(jìn)行。4、對(duì)催化劑的回收進(jìn)行了初步研究,采用逐級(jí)水洗和水渣分離的方法將盡可能多的催化劑富集到溶液當(dāng)中,然后再負(fù)載在新鮮待反應(yīng)的煤焦上,進(jìn)行催化氣化“一步法”煤制天然氣研究。研究表明當(dāng)洗滌時(shí)間4h,水渣比20：1,洗滌次數(shù)為4次,攪拌速率400 r·min-1,催化劑可回收80%左右。最后對(duì)煤-水蒸氣催化氣化生產(chǎn)天然氣工藝進(jìn)行了初步改進(jìn)。
[Abstract]:Energy is the basis of social and economic development, in view of the basic national conditions of rich coal and poor gas. The development of clean coal technology is an important guarantee to realize energy security in China. One-step coal technology for natural gas production refers to the reaction between pulverized coal particles and the water vapor flowing in under the action of catalyst. The technology of producing natural gas from coal gasification and methanation simultaneously in a reactor, in which the heat released from the methanation reaction provides part of the heat required for the coal gasification reaction. Compared with traditional coal gasification conversion technology (two-step method), one-step coal production technology has less equipment, less investment and lower energy consumption. Therefore, it has become a new research hotspot. In this paper, a fixed-bed reactor was used to study the preparation of one-step coal to natural gas catalyst, the effects of process parameters on the reaction were investigated in detail, and a kinetic model was established. Finally, the recovery and process improvement of the catalyst were studied. The specific work was as follows: 1. K-Ni composite catalyst was prepared by impregnation method, and the catalyst was prepared in a fixed-bed reactor. The catalytic performance of the catalyst with different active components and the effect of coal on the catalyst performance were investigated. The results showed that the active components K and Ni in the K-Ni composite catalyst had synergistic effect. K2Ni02 and K3M2O4 with high activity can accelerate the reaction rate. The catalytic effect of K: Ni2: 1 is 2-3 times as much as that of one-component K2SO4. The introduction of CaO can effectively absorb the CO _ 2 produced by the reaction and promote the reaction to the direction of the formation of CH4. At K: Ni: 2: 1: 1.5, the methane content increased by 40% or so compared with that without CaO. The temperature and pressure were investigated. The effects of catalyst loading amount and initial water-carbon ratio on the reaction were investigated, and the optimum process conditions were determined. The results showed that the carbon conversion increased obviously when the temperature was raised, and the reaction temperature was lower than 700 鈩，

本文編號(hào)：1379835