牦牛粪生物质燃烧特性及动力学研究

Study on combustion characteristics and kinetics of yak manure

为更加科学化利用牦牛粪,研究牦牛粪生物质在不同条件下热裂解机理,实现高纬度区域资源最大化合理应用,在不同升温速率(10℃/min、20℃/min和30℃/min)下,采用热重分析法分析牦牛粪生物质的燃烧特性,考察其着火、燃尽及综合燃烧特性;采用等转换方法Kissinger-Akahira-Sunose(KAS)和Ozawa-Flynn-Wall(OFW)计算活化能等动力学参数。基本特性分析结果表明:牦牛粪生物质具有挥发性高,N、S元素含量低,燃烧生成物中污染物含量低的特点。热重试验结果表明:较低的升温速率有助于热量更好地向燃料内部传递,从而造成更少的燃烧残余;而在较高的升温速率下,燃烧特性指数增加近2.5倍,表现出良好的燃烧性能。动力学分析结果表明:活化能主要分布于50~95 kJ/mol之间,两种方法计算的平均活化能分别为70.97 kJ/mol和72.83 kJ/mol。为牦牛粪生物质的进一步利用提供理论依据和相关数据支撑。

In order to use yak dung more scientifically,the thermal cracking mechanism of yak dung biomass was investigated under different conditions to maximize the rational application of resources in high latitude regions.This paper aims to investigate the physicochemical properties and combustion characteristics of yak manure as a potential fuel energy.The physicochemical analysis results showed that the yak manure had a higher volatile matter and heating value.The combustion experiments were carried out using thermogravimetry analysis at different heating rates(10 ℃/min、20 ℃/min and 30 ℃/min),while the ignition temperature,burnout temperature and combustion characteristics index were calculated.Two kinetic models of Kissinger-Akahira-Sunose(KAS) and Ozawa-Flynn-Wall(OFW) were applied to calculate the kinetic parameter.The basic characteristic analysis results showed that the biomass of yak dung had the characteristics of high volatility,low content of N and S elements and low content of pollutants in combustion products.The thermogravimetric test results showed that the lower heating rate was conducive to better heat transfer into the fuel,resulting in less combustion residue.While at the higher heating rate,the combustion characteristic index increased by nearly 2.5 times,leading to good combustion performance.The kinetic analysis results showed that the activation energy was mainly distributed between 50-95 kJ/mol.The average activation energy calculated by the two methods was 70.97 kJ/mol and 72.83 kJ/mol respectively.Combining with the above results,this study can provide a theoretical basis and relevant data support for the further utilization of yak manure.