烟草秸秆与石墨碳混烧特性及动力学分析

Characteristics and kinetic analysis of tobacco straw and graphite carbon mixed burning

本文采用TG-DTG-DSC联用技术对烟草秸秆、石墨碳以及两种燃料的混合物进行热重试验,研究其着火特性、燃尽特性以及综合燃烧特性。采用动力学方法分析了燃料的燃烧机理,并通过计算获得了燃烧动力学参数。结果表明:烟草秸秆的着火与燃尽性能较好;石墨碳最差,混合物着火过程由烟草秸秆控制,燃尽性能由石墨碳控制。石墨碳综合燃烧特性较差,在掺混烟草秸秆后其燃烧特性得到明显改善。动力学分析表明,烟草秸秆的燃烧在低温段符合二级动力学模型,高温段符合三级动力学模型,纯石墨碳的燃烧符合三级动力学模型,两者混合物的燃烧在不同阶段表现出了不同的动力学模型,同时烟草秸秆的燃烧可为石墨碳的燃烧提供热量,从而促进石墨碳的燃烧,其活化能最多降低101 kJ/moL。

In this paper,thermogravimetric tests were carried out on tobacco straw,graphitic carbon,and a mixture of the two fuels using the coupled TG-DTG-DSC technique to investigate their ignition,burnout,and integrated combustion characteristics;the combustion mechanism of the fuels was analyzed using kinetic methods,and the combustion kinetic parameters were calculated.The results showed that the ignition and combustion characteristics of tobacco straw were better than those of graphite carbon,the ignition process of the mixtures was controlled by tobacco straw,and the combustion characteristics were controlled by graphite carbon;the comprehensive combustion characteristics of graphite carbon were poor,and the combustion characteristics of graphite carbon were significantly improved after mixing with tobacco straw.The kinetic analysis showed that the combustion of tobacco straw conformed to the secondary kinetic model in the low-temperature section and the tertiary kinetic model in the high-temperature section.The combustion of pure graphitic carbon conformed to the tertiary kinetic model.The combustion of the two mixtures showed different kinetic models at different stages.Meanwhile,the combustion of tobacco straw can provide heat for the combustion of graphitic carbon and promote the combustion of graphitic carbon.The activation energy of graphitic carbon was reduced by 101 kJ/mol.