铝灰自携及外源金属催化对废轮胎热解产物的影响
- Catalytic effect of the aluminum dross self-carried and foreign metals on pyrolysis products of waste tires
- 摘要：催化热解是有效解决大量废轮胎亟待处置利用困境的技术之一，金属催化剂的使用可促进固废裂解，提高热解产物品质。铝灰作为制铝行业产生的危险废物，含有丰富的金属元素，本研究利用铝灰和Fe改性的铝灰作为催化剂升级废轮胎的热解产物。根据C-R模型和Malek法确定了最佳的动力学机理函数是球对称的三维扩散（D3）。在800 ℃，与无催化热解相比，铝灰催化的CH4和H2的产气率分别提升2%和3%，Fe改性铝灰为催化剂时两者进一步提升13.6%和21%，显著提高合成气品质。铝灰和Fe改性铝灰中的晶格氧促进C-O和C-C键重构，催化热解油中的芳香族化合物从80.98％逐渐减少至68.06%和36.06%，分解转化为链状化合物。此外，废轮胎自身存在的酸性位点促使Zn和S结合为Zn(SO)4，在热解过程中协同脱除。本研究提出协同处置固体废物和危险废物的方法，提高废轮胎的利用价值，减少环境污染，为固体废物的高值资源化提供科学依据。
- Abstract：Catalytic pyrolysis is one of the technologies that can effectively solve the dilemma of large quantities of waste tires that need to be disposed of urgently, and the use of metal catalysts can promote the cracking of solid wastes and improve the quality of pyrolysis products. Aluminum dross (AD), a hazardous waste generated from the aluminum manufacturing industry, is rich in metal elements. In this study, AD and Fe-modified AD were used as catalysts to upgrade the pyrolysis products of waste tires. The optimum kinetic mechanism function was determined to be spherically symmetric three-dimensional diffusion (D3) based on the C-R model and Malek's method. Compared with pyrolysis of waste tires at 800 °C, CH4 and H2 yields were upgraded by 2% and 3% for AD as catalyst, and by 13.6% and 21% for Fe-modified AD catalyst, which significantly improved the syngas quality. Lattice oxygen in AD and Fe -based AD promotes C-O and C-C bond reconfiguration, and the aromatic compounds in catalytic pyrolysis tar are gradually reduced from 80.98％ to 68.06% and 36.06%, and are decomposed into chain compounds. The acidic sites of waste tires promote the combination of Zn and S into Zn(SO)4, which is removed cooperatively in the pyrolysis process. In this study, the method of collaborative disposal of solid waste and hazardous waste is proposed to improve the utilization value of waste tires, reduce environmental pollution, and provide a scientific basis for the high-value recycling of solid waste.
