生物质焦制备条件对其燃烧反应特性的影响(英文)

Influence of preparation conditions on the combustion reactivity of chars produced from the fast pyrolysis of biomass

在热重分析仪上,研究了生物质焦的制备条件对其燃烧反应特性的影响。生物质焦由闪速裂解技术制得,裂解温度为748K、773K和823K;原料含水质量分数为0、7.0%和11.3%。研究发现,生物质焦中挥发性物质的质量分数和H/C质量比随裂解温度的增加而降低,其燃烧反应性随裂解温度的增加而降低;与高裂解温度条件下制得的生物质焦相比,低裂解温度条件下制得的生物质焦具有较高的反应活化能和对燃烧温度更敏感。原料含水量对生物质焦的燃烧反应特性影响很小;但对高裂解温度条件下制得的生物质焦中的挥发性组分含量有较大的影响。简化的生物质焦本征燃烧反应幂函数动力学模型可以很好地描述其燃烧行为。

The influence of preparation conditions, such as pyrolysis temperature and feed moisture content, on the combustion reactivity of chars produced from spruce wood by the flash pyrolysis has been investigated using a thermogravimetric analyser （TGA）. The chars were produced in a fluidised bed reactor at 748 K, 773 K and 823 K, and with wood feed containing different moisture contents of 0, 7.0% and 11.3%. It was found that the reactivity of a char in chemical kinetic control regime increased with decreasing pyrolysis temperature, and the volatile matter （VM） content and H/C ratio in chars also increased with decreasing pyrolysis temperature. There may have a direct relationship between the reactivity of chars and the combination of VM and H/C. In addition, chars produced under lower pyrolysis temperature possess higher activation energy and are more sensitive to combustion temperature, compared with those produced under higher pyrolysis temperature. It was found that feed moisture content has only a minor influence on char reactivity but has a significant effect on the volatile material content of chars produced at higher pyrolysis temperatures. Finally, a simple power-law kinetic model that has been employed to properly describe the char combustion.