【作者】 穆家华；

【导师】 徐绍平；

【作者基本信息】 大连理工大学 ， 化学工艺， 2008， 硕士

【摘要】 本论文工作属于国家自然科学基金资助项目“外循环并流移动床生物质催化气化制富氢气体体系的构建”(编号:50776013)的一部分。为改善未来的能源结构和缓解目前严重的环境污染问题,人们越来越重视清洁能源—氢能的开发和利用。生物质催气化制氢是富有发展前景的利用可再生资源制氢技术。但是,制约目前生物质气化制氢技术发展的主要问题是产气中含量低和焦油含量高。水蒸汽作为气化剂和使用催化剂是提高产气中含量和降低焦油含量的有效手段。基于此,本论文提出了用循环固体热载体法的外循环逆流移动床催化气化制氢工艺,目标是减少焦油产生和提高产气中含量。反应系统由气固逆流移动床气化器、热解器和快速流化床燃烧器构成,燃烧器和热解器、燃烧器与气化器之间的气氛独立分开。催化剂同时作为固体热载体在三器间循环,将燃烧半焦和催化剂积炭释放的热量提供给气化、热解反应。在灼热固体热载体加热的条件下,热解器内生物质快速热解,气化器内热解焦油水蒸气催化转化顺序发生,而热解半焦、催化剂积炭燃烧处于燃烧器中,解决了催化剂再生的问题。本气化工艺综合了生物质快速热解、焦油水蒸气催化转化、热载体加热和催化剂再生无切换连续进行等特点。由于气化所需热量是通过燃烧催化剂积炭和半焦实现的,这使得生物质中的氢最大限度地转化为目的产物氢气成为可能。本论文主要包括如下四部分内容:1)对外循环逆流移动床生物质催化气化的工艺系统进行了物料衡算和热量衡算;2)设计建造了一套实验室连续循环装置统,主要设计内容:热解器、气化器、燃烧器及其附属设备、生物质进料系统、热载体循环系统、产气净化系统等等;3)进行了实验装置的冷态试验,考察了气化器、热解器和提升管系统,实现了固体热载体的稳定循环,为热态试验打下了基础;4)以白松为原料,进行了实验装置的初步热态测试,验证了外循环移动床生物质催化气化工艺的可行性。更多还原

【Abstract】 The research is a part of the project Supported by National Natural Science Foundation, named as "External concurrent circulating moving bed catalytic gasification system of biomass for hydrogen production" (serial number of the subject:50776013).For optimizing the energy utilizations and reducing environmental problems, more and more people pay much attention to hydrogen energy. Gasification of the renewable biomass for hydrogen production is a promising technology. However, there are still many obstacles required to resolve until the commercial breakthrough could be obtained, such as high tar content in dry gas and low hydrogen yield. The addition of steam and catalyst favor hydrogen production and tar reduction.In this thesis, a novel process of catalytic gasification of biomass with solid heat carrier is proposed, which is called External Circulating Countercurrent Moving-Bed gasification system. The gasification system is composed of three reactors, a gas-solid countercurrent moving-bed gasifier, a pyrolyzer and a riser-type combustor, and the gases are completed separated between the combustor and the other reactors. A circulation loop of bed material is achieved through the three reactors. The circulating bed material acts as not only solid heat carrier from the combustor to the gasifier, which supplies the required energy of gasification reactions of biomass, but also catalyst in tar reduction. Rapid pyrolysis of biomass in the pyrolzer, catalytic reforming of tar in the gasifier sequently occurs. A dry gas with low tar content and high hydrogen content should be obtained in the process. In the combustor, reheating of solid heat carrier and regenerated catalyst are made by burning off the residual char and coke on catalyst. At the same time, the highest yield of hydrogen can be obtained from biomass. During the process, fast prolysis of biomass, reforming of tar, heating of solid carrier and catalyst regeneration occur simultaneously and continuously.This paper mainly includs four parts as follows:1) Material balance and heat balance of the process system of the external circulating countercurrent moving-bed gasification were calculated.2)A lab-scale facility was designed and established to demonstrate this process concept, which includes a pyrolyzer, a gasifier, a combustor, a feed system of biomass , a circulating loop of heat carrier solid and a purification system of product gas and so on. 3) By a series of cold state experiments, we investigated the performances of the gasifier, the pyrolyzer and the combustor and carried out the steady circulation of solid heat carrier for the hot state experiments.4) A series of preliminary hot state experiments were seriously conducted with pine sawdust as the material. The experiments verified the hydrogen production is feasible.更多还原