配煤燃烧过程的叠加特性及其动力学参数的表观性研究

Superposition characteristics of combustion process and representational ability of kinetic parameters of blended coal

配煤燃烧是已被广泛应用的煤质和燃烧调控方法。配煤属于物理过程,但其燃烧过程在不考虑氧量竞争和温度的外在因素相互影响时,是物理过程还是存在显著的化学过程交互,并没有明确的文献论证。本文对12种不同差异的煤样及其28组配煤做了热分析实验,将原煤的热重曲线按照配煤比例进行质量加权叠加,得到配煤的计算热重曲线与实验热重曲线具有显著的重现性(R^(2)>0.999)。说明在热天平的恒定氧量和控制温度条件下,配煤的燃烧过程表现为原煤燃烧过程的物理叠加。配煤的燃烧过程受原煤反应性差异的影响而呈现单峰或多峰的特征,将其视作原煤计算动力学参数的表观性不再具有可靠的置信度。

Coal blending has been widely used as coal quality and combustion control.The blending of coal is a physical process.If the oxygen competition and temperature interaction are ignored,whether the combustion of blended coal is physical process or contains significant chemical interplay has not been discussed specially in the previous literatures.In this paper,thermo-gravimetric experiments were carried out on 28 blended coals which involve 12 raw coals.After the raw coals’TG(thermo-gravimetric)curves were averaged by weight,the calculated TG curves are almost identical to the experimental TG curves of blended coal respectively(R^(2)>0.999).The result shows that,under the condition of constant oxygen content and controlled temperature,the combustion process of blended coal accords with physical superposition of the raw coals.Affected by the reactivity difference of raw coals,the combustion process of blended coal presents either unimodal or multimodal.The kinetic parameters of the blended coal which calculated as raw coal would no longer satisfy the stable confidence.