废旧纺织物在二氧化碳气氛下裂解和气化机理研究

发布时间：2018-07-25 19:45

【摘要】：废旧纺织物作为一种固体垃圾,由于其排放量大、含能高和容易分类的优点正在被人们越来越关注。而废旧纺织物在CO2气氛下裂解和气化技术不但可以充分利用高能原料,还可以有效的转换CO2,减少大气中温室气体的排放。本文研究了CO2气氛下废旧纺织物的裂解和气化特性及机理,及催化剂对催化裂解和气化过程的促进作用,以提高纺织物的催化裂解-气化特性。具体工作如下:首先,为得到CO2气氛下废旧纺织物的裂解和气化特性和机理,利用热重分析仪研究了不同废旧纺织物(涤纶质、棉质和羊毛质)的裂解和气化特性。用扫描电镜和拉曼光谱分析了焦的结构特性,用缩核模型计算了裂解和气化过程的动力学参数,用GC和GC-MS分析了纺织物裂解气体和液体产物。结果表明:由于纺织物种类不同,三种纺织物的裂解和气化特性(包括产物种类、含量)不同,如涤纶质、棉质和羊毛质裂解产物中相对含量最高的分别为苯甲酸(C7H6O2)、乙酸(C2H4O2)和氰乙烷(C3H5N);两个过程的反应动力学和热力学也不同,涤纶质、棉质和羊毛质的裂解活化能分别为162.4kJ/mol、103.1kJ/mol和110.0kJ/mol,对应焦的气化活化能分别为178.2kJ/mol、144.5kJ/mol和79.4kJ/mol。进一步,为强化废旧纺织物在CO2气氛下的裂解和气化反应动力学,利用热重分析仪、X射线衍射仪和扫描电镜研究了多种催化剂对废旧纺织物(涤纶质、棉质和羊毛质)裂解和气化过程的促进作用,分析了废旧纺织物在不同催化剂含量和反应温度下的催化裂解和气化特性。结果表明5 wt%ZnO对纺织物裂解过程催化效果最好而5wt%Fe2O3对气化过程催化效果最好。混合纺织物无催化剂和负载5wt%ZnO催化剂的裂解反应活化能分别为100.7kJ/mol和65.1kJ/mol,气化过程无催化剂和负载5wt%Fe2O3催化剂的反应活化能分别为153.0kJ/mol和89.0kJ/mol。最后,为研制一种同时适用于裂解和气化反应的催化剂,本文利用共沉淀法制备一种Zn-Fe复合催化剂。研究发现,当裂解和气化反应中含有复合催化剂时,纺织物的裂解和气化反应活化能分别为57.1kJ/mol和83.3kJ/mol,均优于单一催化剂的催化效果。本文的研究有利用废旧纺织物-CO2的资源化利用技术的发展。
[Abstract]:As a kind of solid waste, waste textile has been paid more and more attention because of its large emission, high energy content and easy classification. The pyrolysis and gasification of waste textiles in CO2 atmosphere can not only make full use of high-energy feedstock, but also can effectively convert CO _ 2 and reduce greenhouse gas emissions in the atmosphere. In this paper, the pyrolysis and gasification characteristics and mechanism of waste textiles in CO2 atmosphere and the catalytic effect of catalysts on catalytic cracking and gasification process were studied to improve the catalytic pyrolysis and gasification characteristics of textile fabrics. The main work is as follows: firstly, in order to obtain the pyrolysis and gasification characteristics and mechanism of waste textiles in CO2 atmosphere, the pyrolysis and gasification characteristics of different waste textile fabrics (polyester, cotton and wool) were studied by thermogravimetric analyzer. The structural characteristics of coke were analyzed by scanning electron microscopy and Raman spectroscopy. The kinetic parameters of pyrolysis and gasification were calculated by using the shrinking nucleus model. The pyrolysis gas and liquid products of textile were analyzed by GC and GC-MS. The results show that the pyrolysis and gasification characteristics (including the type and content of the products) of the three textile fabrics are different due to the different types of textile fabrics, such as polyester, The highest relative contents of cotton and wool pyrolysis products were benzoic acid (C7H6O2), acetic acid (C2H4O2) and cyanoethane (C3H5N), and the reaction kinetics and thermodynamics of the two processes were also different. The activation energies of decomposition of cotton and wool were 162.4 kJ / mol 103.1 KJ / mol and 110.0 KJ / mol, respectively, and the corresponding gasification activation energy of char were 178.2 kJ / mol 144.5 kJ / mol and 79.4 kJ / mol / mol, respectively. Furthermore, in order to enhance the kinetics of pyrolysis and gasification of waste textiles in CO2 atmosphere, the effects of various catalysts on waste textile (polyester) were studied by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The catalytic cracking and gasification characteristics of waste textile under different catalyst content and reaction temperature were analyzed. The results showed that 5 wt%ZnO had the best catalytic effect on the pyrolysis of textile and 5wt2O3 had the best catalytic effect on gasification. The activation energy of non-catalyst and supported 5wt%ZnO catalyst is 100.7kJ/mol and 65.1 KJ / mol, respectively. The activation energy of non-catalyst and supported 5wt2O3 catalyst in gasification process is 153.0kJ/mol and 89.0kJ / mol, respectively. Finally, in order to develop a catalyst suitable for both cracking and gasification, a Zn-Fe composite catalyst was prepared by coprecipitation method. It was found that the activation energy of decomposition and gasification reaction of textile was 57.1kJ/mol and 83.3 KJ / mol, respectively, which was better than that of single catalyst when there were complex catalysts in the cracking and gasification reactions. In this paper, the development of resource utilization technology of waste textile-CO _ 2 is discussed.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X705

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