本文選題：甘油 + 重整　； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：生物柴油具有綠色環(huán)保可再生等優(yōu)勢,生物柴油的大量制備導(dǎo)致其副產(chǎn)物甘油大多被浪費(fèi),甘油重整制氫為甘油利用提供了一種有效途徑。為了能夠提高甘油利用率和氫氣產(chǎn)率,重整強(qiáng)化手段的研究成為了近年來的研究熱點(diǎn)。流化床反應(yīng)器具有更好的流動性以及傳熱傳質(zhì)性,在甘油重整制氫中具有廣闊的前景。因此,以甘油水蒸氣重整制氫為研究對象,針對流化床內(nèi)甘油重整過程及其強(qiáng)化手段進(jìn)行熱力學(xué)模擬以及流體動力學(xué)模擬研究�？紤]到甘油重整制氫為吸熱反應(yīng),為了減少能量投入,利用氧化反應(yīng)釋放熱量從而達(dá)到自熱的狀態(tài),構(gòu)建出甘油水蒸氣自熱重整反應(yīng)體系,對不同操作條件下的重整體系進(jìn)行熱力學(xué)分析。研究表明,自熱狀態(tài)雖然能夠有效地減少外界能量的投入,但氫氣產(chǎn)量卻會明顯減少。考慮體系內(nèi)加入吸收劑,通過反應(yīng)發(fā)生平衡移動,促進(jìn)反應(yīng)進(jìn)行,同時可以通過吸收反應(yīng)放熱使體系達(dá)到自熱狀態(tài)。通過對氧化鈣作為二氧化碳吸收劑的甘油重整反應(yīng)體系進(jìn)行熱力學(xué)模擬,結(jié)果表明,氧化鈣的加入使氫氣產(chǎn)量增加,最大氫氣產(chǎn)量所對應(yīng)的操作溫度降低,起到了明顯的強(qiáng)化作用。同時由于碳酸鈣高溫分解等因素,反應(yīng)器溫度不能高于850K,氧化鈣-甘油投料比在3~4之間比較適合于強(qiáng)化重整反應(yīng)的進(jìn)行�？紤]到半透膜可以有效地將反應(yīng)體系內(nèi)部的氫氣分離,促使反應(yīng)平衡發(fā)生移動,對甘油重整制氫過程起到強(qiáng)化作用,對甘油自熱除氫體系進(jìn)行了熱力學(xué)分析。結(jié)果表明,半透膜的除氫強(qiáng)化手段能夠使氫氣產(chǎn)率增加,抵消氧氣的引入所帶來的負(fù)面影響,并且氫的分離系數(shù)越大,效果越明顯。但氫氣分離的同時會促進(jìn)反應(yīng)體系內(nèi)部的甲烷化反應(yīng),增加積碳的產(chǎn)量。為了探究粗甘油重整的可行性,反應(yīng)體系內(nèi)引入乙醇雜質(zhì)。結(jié)果表明,乙醇的引入會對氫氣產(chǎn)量產(chǎn)生負(fù)面影響,并且這種負(fù)面影響會隨著氫氣分離系數(shù)的增大而增強(qiáng)。應(yīng)用本文建立的氣固多相流體模型,模擬計算了流化床反應(yīng)器內(nèi)甘油水蒸氣重整制氫過程。結(jié)果表明,流化床內(nèi)顆粒呈現(xiàn)出明顯的流化狀態(tài)。床層內(nèi)部有明顯的稀相區(qū)和密相區(qū),伴隨著顆粒聚團(tuán)行為以及氣泡生成和運(yùn)動現(xiàn)象,并且反應(yīng)器內(nèi)部存在著顆�；亓鳜F(xiàn)象。反應(yīng)器中顆粒擬溫度表現(xiàn)出隨著顆粒濃度的逐漸增加而減小的分布趨勢。通過對流化床內(nèi)反應(yīng)特性進(jìn)行研究發(fā)現(xiàn),在流化床反應(yīng)器內(nèi)部,甘油和水蒸氣作為反應(yīng)物,在反應(yīng)器底部快速分解,生成一系列生成物氣體,其中氫氣是甘油重整的主要生成物。將有吸收強(qiáng)化和未吸收強(qiáng)化的甘油重整制氫過程進(jìn)行對比,證明體系內(nèi)部加入氧化鈣吸收二氧化碳作為吸收強(qiáng)化手段,不但能夠使反應(yīng)體系達(dá)到自熱狀態(tài),還能夠有效地提高甘油的轉(zhuǎn)化率以及氫氣的產(chǎn)率。吸收強(qiáng)化后,反應(yīng)器出口處氫氣份額由47%提升到了55%,一氧化碳和甲烷的份額都相對的降低。
[Abstract]:Biodiesel has the advantages of green environment protection and renewable. The production of biodiesel leads to the waste of glycerol. Glycerol reforming to produce hydrogen provides an effective way for the utilization of glycerol. In order to improve glycerol utilization and hydrogen yield, reforming enhancement has become a hot research topic in recent years. Fluidized bed reactor has better fluidity, heat and mass transfer, and has a broad prospect in glycerol reforming hydrogen production. Therefore, the hydrodynamic simulation and thermodynamic simulation of glycerol reforming in fluidized bed were carried out. Considering that the hydrogen production of glycerol reforming is an endothermic reaction, in order to reduce the energy input, the oxidation reaction is used to release heat so as to reach the state of self-heating, and a self-heating reforming system of glycerol water vapor is constructed. Thermodynamic analysis of reforming system under different operating conditions was carried out. The results show that although the self-heating state can effectively reduce the external energy input, the hydrogen production will be significantly reduced. Considering the addition of absorbent in the system, the equilibrium shift of the reaction occurs and the reaction can be promoted. At the same time, the self-heating state of the system can be achieved by the absorption reaction exothermic. The thermodynamic simulation of glycerol reforming reaction system with calcium oxide as carbon dioxide absorbent was carried out. The results showed that the addition of calcium oxide increased the hydrogen production and reduced the operating temperature corresponding to the maximum hydrogen production. Has played the obvious enhancement function. At the same time, because of the decomposition of calcium carbonate at high temperature, the reactor temperature can not be higher than 850K, and the ratio of calcium oxide to glycerol is more suitable for the enhanced reforming reaction. Considering that the semi-permeable membrane can effectively separate the hydrogen in the reaction system and promote the shift of the reaction equilibrium, the hydrogen production process of glycerol reforming is strengthened, and the thermodynamics analysis of the self-heating dehydrogenation system of glycerol is carried out. The results show that the enhancement of hydrogen removal by semi-permeable membrane can increase the hydrogen yield and counteract the negative effect brought by the introduction of oxygen, and the higher the separation coefficient of hydrogen is, the more obvious the effect is. However, hydrogen separation can promote the methanation reaction in the reaction system and increase the yield of carbon deposition. In order to explore the feasibility of crude glycerol reforming, ethanol impurities were introduced into the reaction system. The results showed that the introduction of ethanol had a negative effect on hydrogen production, and the negative effect would increase with the increase of hydrogen separation coefficient. Based on the gas-solid multiphase fluid model established in this paper, the hydrogen production process of glycerol steam reforming in a fluidized bed reactor was simulated and calculated. The results show that the fluidized bed particles show an obvious fluidization state. There are obvious dilute and dense phase regions in the bed, accompanied by particle agglomeration, bubble formation and movement, and particle reflux in the reactor. The particle pseudo temperature in the reactor decreases with the increase of particle concentration. By studying the reaction characteristics in the fluidized bed, it is found that in the fluidized bed reactor, glycerol and water vapor are used as reactants, which decompose rapidly at the bottom of the reactor and produce a series of resultant gases. Hydrogen is the main product of glycerol reforming. By comparing the hydrogen production process of glycerol reforming with and without absorption enhancement, it is proved that adding calcium oxide to absorb carbon dioxide as a means of absorption enhancement can not only make the reaction system self-heated. The conversion of glycerol and the yield of hydrogen can also be increased effectively. After absorption enhancement, the hydrogen share at the outlet of the reactor increased from 47% to 55%, and the carbon monoxide and methane share decreased relatively.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ116.2

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