本文選題：褐煤　切入點(diǎn)：天然氣　出處：《青島科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著經(jīng)濟(jì)的迅速發(fā)展和能源需求的不斷增加,我國的煤炭資源消耗巨大,煙煤、無煙煤等高階煤炭資源儲(chǔ)量日益減少。因此,褐煤、氣煤等低階煤的利用越來越受到人們的重視。天然氣作為一種低碳環(huán)保、高效清潔的綠色能源,目前在很多領(lǐng)域得到了廣泛的應(yīng)用,而“富煤、貧油、少氣”的能源結(jié)構(gòu)導(dǎo)致我國天然氣供需矛盾日益突出,因此通過煤制天然氣技術(shù)將低階煤炭資源轉(zhuǎn)化為高效清潔的天然氣資源是符合我國能源可持續(xù)發(fā)展的一條重要道路。通過煤制天然氣不僅可以使得煤炭資源得到深度利用,提高能源利用效率,還能緩解我國天然氣短缺造成的供需矛盾,對(duì)保障我國的能源安全具有非常重大的意義。本文采用“一步法”褐煤直接制天然氣,是將褐煤顆粒、催化劑混合后放入固定床反應(yīng)器中,并在高溫下通入水蒸氣,該反應(yīng)器內(nèi)同時(shí)發(fā)生煤氣化和合成氣甲烷化反應(yīng),煤氣化反應(yīng)所需要的部分熱量可由甲烷化反應(yīng)提供,從而降低了反應(yīng)的能耗。該技術(shù)與煤氣化制得合成氣再由合成氣轉(zhuǎn)化為甲烷的間接甲烷化技術(shù)相比具有投資少,能耗低等優(yōu)點(diǎn)。本文主要針對(duì)褐煤“一步法”制天然氣催化劑的制備及性能進(jìn)行了研究,主要內(nèi)容如下。首先,以γ-Al2O3為載體,通過浸漬法分別制備了以氫氧化鉀、硝酸鎳及鉬酸銨為前驅(qū)體的單組分褐煤直接甲烷化催化劑。并在650℃,2 MPa的條件下采用“一步法”于固定床反應(yīng)器中對(duì)上述單組分催化劑的催化氣化及甲烷化性能進(jìn)行了考察。實(shí)驗(yàn)結(jié)果表明,在K30催化劑與褐煤煤焦表面的相互作用能有效促進(jìn)褐煤的氣化,北宿褐煤的碳轉(zhuǎn)化率提高較大,合成氣及甲烷含量較高,說明其具有較好的催化氣化及甲烷化效果。Ni15催化劑能有效提高褐煤碳轉(zhuǎn)化率及甲烷產(chǎn)量,而少量Mo基催化劑對(duì)褐煤的催化具有一定的促進(jìn)作用,但負(fù)載量過多會(huì)造成載體孔道的堵塞并在載體表面發(fā)生團(tuán)聚現(xiàn)象,從而阻礙了催化反應(yīng)的正向進(jìn)行,降低了催化劑的活性。其次,以γ-Al2O3為載體,通過浸漬法制備了雙組分催化劑Ni-Mo催化劑、Ni-Ca催化劑和Ni-K催化劑。并考察了雙組分催化劑對(duì)褐煤催化氣化及甲烷化性能的影響。Ni-Mo雙組分催化劑催化效果不佳,甚至低于單組分的Ni基催化劑,說明Ni-Mo雙組分催化劑對(duì)于褐煤的催化作用較弱。Ni-Ca雙組分催化劑有利于褐煤的催化氣化及甲烷化,少量Ca對(duì)于褐煤的碳轉(zhuǎn)化率、合成氣含量及甲烷產(chǎn)量都有了大量的提高,特別是Ni15Ca10催化劑的催化效果較好。當(dāng)Ca負(fù)載量增多時(shí),催化效果有所下降。而Ni-K雙組分催化劑相較于Ni-Mo催化劑和Ni-Ca催化劑的催化作用明顯提高,且隨著K負(fù)載量的不斷增加,其催化效果明顯加強(qiáng)。當(dāng)K負(fù)載量為30%時(shí),即Ni15K30催化劑的催化效果最佳,褐煤的碳轉(zhuǎn)化率、合成氣含量和甲烷含量都有了大幅度的提升。當(dāng)溫度為650-C、2 MPa、水碳比為1：1時(shí),褐煤的碳轉(zhuǎn)化率及甲烷產(chǎn)量能達(dá)到最佳。本實(shí)驗(yàn)采用修正隨機(jī)孔模型、均相反應(yīng)模型和收縮核模型對(duì)三種雙組分催化劑催化褐煤甲烷化反應(yīng)過程進(jìn)行了擬合。結(jié)果表明,修正隨機(jī)孔模型的對(duì)其擬合度最高,說明修正隨機(jī)孔模型能很好地揭示三種催化劑對(duì)褐煤催化甲烷化的行為,并證明該反應(yīng)的控制步驟為界面反應(yīng)控制。
[Abstract]:Along with the rapid economic development and increasing energy demand, China's coal resources consumption is huge, bituminous coal, anthracite coal resources reserves of high order is reduced. Therefore, the use of lignite, gas coal and other low rank coal has been paid more attention. The natural gas as a low carbon environmental protection, efficient and clean green energy at present, in many fields has been widely used, and rich in coal, oil, energy structure less gas "leads to the contradiction of China's natural gas supply and demand have become increasingly prominent, so the coal gas technology will low rank coal resources into natural gas resources and efficient cleaning is consistent with an important road of sustainable energy development country. By coal and natural gas can not only make the depth of the use of coal resources, improve energy efficiency, but also alleviate the contradiction between supply and demand of China's natural gas shortage caused, to protect China's energy security It has a very important significance. This paper uses the "direct preparation of natural gas by lignite, the lignite particles mixed into the catalyst in fixed bed reactor, and the water vapor at high temperature, simultaneous coal gasification and syngas methanation reaction in the reactor part to heat the coal gasification reaction can be provided by the methanation reaction, thereby reducing the energy consumption of the reaction. The technology of coal gasification process and synthesis gas is converted from syngas for indirect methanation technology of methane compared with less investment, lower energy consumption. In this paper, the lignite" one-step "natural gas catalyst preparation and properties of study, the main contents are as follows. First, the gamma -Al2O3 as carrier, was prepared by the impregnation method were prepared by using potassium hydroxide, ammonium molybdate and nickel nitrate as single component lignite precursors direct methanation catalyst. And at 650 DEG C, 2 MP Under the condition of a by using the "one-step" in a fixed bed reactor for the single component catalyst for catalytic gasification and methanation were investigated. The experimental results show that can effectively promote the gasification of lignite in the interaction between K30 catalyst and lignite char surface, the carbon conversion rate of lignite coal is larger, higher synthesis gas and methane content, the catalytic gasification and methanation catalyst.Ni15 good effect can effectively improve the lignite conversion rate of carbon and methane production, and a small amount of Mo based catalyst for catalytic lignite has a certain role, but the load will cause excessive pore blockage and agglomeration of the carrier surface, thereby hinder the positive catalytic reaction, the activity of the catalyst was reduced. Secondly, using gamma -Al2O3 as carrier, prepared by the impregnation method of two-component catalyst and Ni-Mo catalyst, Ni-Ca catalyst Ni-K catalyst was investigated. And the effect of two-component catalyst on the catalytic gasification of lignite and methanation properties of.Ni-Mo bicomponent catalyst effect is poor, even lower than the single component Ni based catalyst, Ni-Mo double component catalyst for the catalytic effect of lignite is weak.Ni-Ca bicomponent catalyst for the catalytic gasification of lignite methane, a small amount of Ca for lignite carbon conversion, the content of synthesis gas and methane production has a lot of improvement, especially good catalytic effect of Ni15Ca10 catalyst. When Ca loading increased, the catalytic effect decreases. And the catalytic effect of Ni-K two-component catalyst compared with Ni-Mo catalyst and Ni-Ca catalyst was improved and, with the increase of K loading, the catalytic effect is obviously enhanced. When the K loading was 30%, the catalytic effect of Ni15K30 catalyst, lignite carbon conversion, synthesis gas The amount and content of methane have been improved greatly. When the temperature is 650-C, 2 MPa, ratio of water to carbon is 1:1, lignite carbon conversion rate and yield of methane can reach the best. This experiment adopts the modified random pore model, homogeneous reaction model and the shrinking core model of three kinds of two-component catalyst of lignite the methanation reaction process was simulated. The results show that the modified random pore model to fit the highest, indicating the modified random pore model can well reveal three kinds of catalysts on the catalytic methanation of lignite, and prove that the control step of the reaction to interface reaction control.

【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ426;TE665.3

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本文編號(hào)：1597806