【作者】 徐翔；

【导师】 张博；

【作者基本信息】 大连理工大学 ， 热能工程， 2015， 硕士

【摘要】 我国一年产生的皮革工业废料约140万吨,目前尚无有效的无害化处理技术,造成大量的堆积,不仅占用宝贵的土地资源,而且对土壤、地下水等环境造成污染。本文探索将粉碎后的皮革废料在气化炉内厌氧环境下气化产生的可燃气体在二燃室内充分燃烧,将其释放的热能用余热锅炉吸收用于发电或供热,可以实现皮革废料的减量化无害化和资源化处理。本文对皮革废料的气化特性、燃烧特性进行实验研究,利用CFD数值模拟技术对气化及燃烧过程进行模拟计算,利用其计算结果设计了气化炉头,最后建立实验平台进行验证。首先,本文对皮革工业废料进行元素分析和工业分析,采用热重分析技术对粉碎后的皮革废料的气化特性、燃烧特性进行研究。主要研究PU革废料的胶纸组分、基布组分不同组分比例在空气气氛下的气化特性和燃烧特性,也研究了其在不同氧气浓度下的气化特性和燃烧特性。研究发现PU革废料中胶质组分的燃烧过程可以分为两个阶段,而基布组分的燃烧过程则只有一个阶段：胶质组分的着火温度低于基布组分,但是燃尽温度却高于基布组分,胶质组分易燃但不易燃尽。空气氛围下,当PU革废料中胶质组分含量较少时,PU革废料的着火特性和燃尽特性均接近于基布组分,易燃尽但不容易着火。PU革废料的燃烧特性指数随着胶质组分的增加而减小；PU革废料的燃烧特性指数,随着氛围中氧气浓度的增加而增高。其次,本文对三种不同长度(500mm、1000mm、2000mm)的气化炉头采用CFD数值模拟技术进行计算,得到其CO、CO2的截面浓度及截面速度,也研究了皮革废料颗粒的轨迹分布,并对气化炉头的结构进行优选设计。研究发现随着气化室长度的增加,气化室出口处的CO和C02浓度分布趋于均匀,皮革废料与空气在气化室内的混合趋于均匀,颗粒在气化室后环室停留时间较大。皮革废料在三种长度结构下的气化室内的碳燃尽率皆大于99%。再次,根据数值模拟计算及优选的结果,对气化炉头进行整体布局,结构参数进行计算。在此基础上进行热力计算,并对气化炉头的保温结构和电加热预燃功率进行校核。最后,建立了小试的实验系统,对皮革气化燃烧进行实验验证。实验表明气化炉气化室燃烧段温度低于设计要求,但可实现稳定气化并在二燃室稳定燃烧；皮革的燃尽程度较高,接近100%。实验系统在给料机的速率偏低,实现了28.8%的设计负荷条件下的运行并仍可实现系统热效率90.38%。燃烧污染物排放低,氮氧化物排放浓度约为400ppm。更多还原

【Abstract】 Leather industrial waste generated in one year amounts up to about 1.4 million tons in our country. Due to the lack in effective processing technology, the waste has accumulated and taken up valuable land resources, and polluted the soil, groundwater and others in environment. This paper investigates the combustion of gas produced by gasification of crushed leather waste under anaerobic conditions within the gasifier in the second combustion chamber, to generate electricity or heat with heat energy released by the waste heat boiler, and to achieve the reduction and treatment of leather waste. This paper studies the gasification characteristics and combustion characteristics of leather waste with experiments, also uses CFD numerical simulation technology for the calculation of gasification and combustion process, designs gasifier head with the calculation results, and finally establishes an experimental platform for authentication.Firstly, the elemental analysis and industry analysis leather industrial waste are conducted. Thermal analysis technique is applied to the study on gasification characteristics and combustion characteristics of leather waste. The main content is the study of components of PU leather scrap tape, the gasification and combustion characteristics of different components of the fabric components in air, and the characteristics at different oxygen concentrations. The study found two phases in glial component combustion process of PU leather waste, in contrast to only one stage in the combustion process of fabric components. And the ignition temperature of glial component is lower than that of the fabric component, but the burnout temperature is higher than that of the fabric component, while the glia component is easy to get burned but not easy to burn completely. In air, when PU leather waste has less glial component content, the ignition characteristics and burnout characteristics are close to those of fabric components, and the PU leather is easy to get burn completely but not easy to get burned. The combustion characteristics index of PU leather waste decreases with the increase of glial component and it increases with the increase in oxygen concentration in the air.Secondly, the CFD numerical simulation technology is used to simulate and calculate the process with gasifier head of three different lengths (500mm,1000mm,2000mm) to generate its CO, CO2-sectional concentration and sections speed, and also to study the trajectory distribution of particles of leather scraps, and to optimize the design of the structure of gasifier head. The study found that with the increase of the gasification chamber length, CO and CO2 concentration distribution at the outlet of the gasification chamber tends to be uniform, leather waste mixture with air in the gasification chamber tends to be uniform, and residence time of the particles in the gasification chamber donut tends to be longer. The burnout rates of leather waste in gasification chamber with three different lengths all exceed 99%.Based on the results of numerical simulation and optimization, the overall layout of the gasifier head is proposed, with structure parameters calculated. Thereafter thermodynamic calculations are made and insulation structure of gastifier head and the pre-combustion power of electrical heating were checked.Finally, a small experimental system is established to conduct leather gasification combustion experiments. Experiments show that gasifier combustion zone temperature of the gasification chamber is below the design requirements, but stable combustion and gasification can be achieved in the second combustion chamber; burnout rate of leather approximates 100%. Experimental system can achieve system thermal efficiency 90.38% with a low rate in feeder, running at 28.8 percent of design load, with nitrogen oxide emissions concentration of about 400ppm.更多还原