基于铜基氧载体的生物质化学链利用研究

发布时间：2018-07-01 09:41

本文选题：化学链燃烧 + 化学链氧解耦　；参考：《华中科技大学》2015年硕士论文

【摘要】：化学链燃烧(CLC)是一项具有解决能源与环境问题潜力的创新性突破技术,与传统的燃烧方式相比,CLC具有低能耗捕集CO2,反应温度低,抑制NOx的产生,实现能量的梯级利用等优点。化学链氧解耦(CLOU)是基于CLC的另一种新型燃烧方式,它的不同之处在于采用特殊的氧载体,该氧载体在低于其氧平衡分压的状态下能够释放出气态的O2,直接与固体燃料发生反应,避免了燃料缓慢的气化过程,从而大大的提高了整个反应的速率。化学链重整(CLR)也是从CLC发展出来的新技术,基本原理相同,它的区别在于目标产物是合成气(CO和H2),而不是热量。生物质是一种可再生新能源,并且在使用过程中不会增加温室气体CO2的排放,其利用方式也一直备受关注。本文将化学链技术与生物质利用相结合,从多个方面进行了基于铜基氧载体的生物质化学链利用实验研究,探讨了其可行性,以及在不同实验条件下的效果。首先采用溶胶-凝胶法制备的CuO/CuAl2O4作为氧载体,木屑作为燃料,在流化床反应器中探究了生物质CLOU的可行性,讨论了温度的影响,并将木屑与无烟煤混合作为燃料,研究其协同作用。随后探究了基于铜基氧载体的生物质CLR利用的可行性,讨论了氧载体和反应器温度对产气组分、产气率、碳转化率、气化效率以及焦油产量的影响。最后引入水蒸气,探究了氧燃比、氧载体、水蒸气-生物质比和温度对生物质CLR过程的影响。结果表明温度对生物质CLOU有较大影响,随着温度的升高,碳转化速率变快;将木屑用于CLOU,CO2捕集效率较低;当木屑与无烟煤参混作为CLOU的燃料时,CO2捕集效率大幅提高。对于生物质CLR,使用铜基氧载体可以得到较高的产气率和碳转化效率,但是产气热值和气化效率相应减小;另外,使用铜基氧载体可以有效减少C2Hm和焦油的产生。在铜基氧载体和铁基氧载体的比较上,并没有一个决定性的结论,铜基氧载体的缺点在于为保证燃料反应器的热平衡牺牲了部分气化效率和产气的低位发热量,铁基氧载体的缺点在于较低的反应性和碳转化率,选择铜基还是铁基氧载体也取决于CLR的目的以及下游气体处理过程。在焦油成分的分析方面,发现使用铜基和铁基氧载体时,大分子化合物含量减少,小分子化合物含量和种类增多,说明氧载体的存在使得焦油中大分子化合物发生了一定程度的分解。
[Abstract]:Chemical chain combustion (CLC) is an innovative breakthrough technology that has the potential to solve energy and environmental problems. Compared with the traditional combustion mode, CLC has the advantages of low energy consumption collecting CO2, low reaction temperature, inhibition of NOx production and the realization of cascade utilization of energy. Chemical chain oxygen decoupling (CLOU) is a new type of combustion mode based on CLC, and it is a new type of combustion method. The difference is that using a special oxygen carrier, the oxygen carrier can release the gaseous O2 under the state of the oxygen equilibrium pressure, which directly reacts with the solid fuel and avoids the slow gasification process of the fuel, thus greatly improving the rate of the whole reaction. The chemical chain reforming (CLR) is also a new technology developed from the CLC. This principle is the same, its difference is that the target product is synthetic gas (CO and H2), not heat. Biomass is a renewable new energy, and it will not increase the emission of greenhouse gas CO2 in the process of use. The feasibility of the biomass chemical chain of copper based oxygen carrier was studied, and its feasibility and effect under different experimental conditions were discussed. First, the CuO/CuAl2O4 prepared by the sol-gel method was used as the oxygen carrier and the sawdust was used as fuel. The feasibility of biomass CLOU was explored in the fluidized bed reactor, the effect of temperature was discussed, and the sawdust was used. The synergistic effect of the mixture of anthracite as fuel was studied. The feasibility of using the copper based oxygen carrier based biomass CLR was investigated. The effects of oxygen carrier and reactor temperature on gas production, gas production, carbon conversion, gasification efficiency and tar yield were discussed. Finally, the oxygen fuel ratio, oxygen carrier, and water vapor were investigated by the introduction of water vapor. The effect of biomass ratio and temperature on biomass CLR process shows that temperature has a great influence on biomass CLOU. With the increase of temperature, the rate of carbon conversion becomes faster; the use of wood chips for CLOU and CO2 capture efficiency is low; when wood and anthracite are mixed as fuel for CLOU, the efficiency of CO2 capture is greatly improved. For biomass CLR, the use of copper base is used. Oxygen carrier can get higher gas production rate and carbon conversion efficiency, but the gas producing calorific value and gasification efficiency decrease correspondingly. In addition, the use of copper base oxygen carrier can effectively reduce the production of C2Hm and tar. The heat balance of the reactor sacrificed the partial gasification efficiency and the low calorific value of gas production. The disadvantage of the iron base oxygen carrier is the lower reactivity and carbon conversion rate. The selection of copper based or iron base oxygen carrier also depends on the purpose of CLR and the process of downstream gas treatment. The use of copper and iron base oxygen carriers in the analysis of tar components is found. At the time, the content of large molecular compounds decreased and the contents and types of small molecular compounds increased. It indicated that the presence of oxygen carriers made the large molecular compounds in tar decomposed to a certain extent.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ038

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