International Journal of Coal Science & Technology Pub Date : 2020-08-17 , DOI: 10.1007/s40789-020-00358-5 Peng Jiang , Yang Meng , Ziyao Lu , Lan Xu , Gang Yang , Xiang Luo , Kaiqi Shi , Tao Wu
This study examined an isothermal CO2 gasification of four chars prepared via two different methods, i.e., conventional and microwave-assisted pyrolysis, by the approach of thermogravimetric analysis. Physical, chemical, and structural behaviours of chars were examined using ultimate analysis, X-ray diffraction, and scanning electronic microscopy. Kinetic parameters were calculated by applying the shrinking unreacted core (SCM) and random pore (RPM) models. Moreover, char-CO2 gasification was further simulated by using Aspen Plus to investigate thermodynamic performances in terms of syngas composition and cold gas efficiency (CGE). The microwave-induced char has the largest C/H mass ratio and most ordered carbon structure, but the smallest gasification reactivity. Kinetic analysis indicates that the RPM is better for describing both gasification conversion and reaction rates of the studied chars, and the activation energies and pre-exponential factors varied in the range of 78.45–194.72 kJ/mol and 3.15–102,231.99 s−1, respectively. In addition, a compensation effect was noted during gasification. Finally, the microwave-derived char exhibits better thermodynamic performances than the conventional chars, with the highest CGE and CO molar concentration of 1.30% and 86.18%, respectively. Increasing the pyrolysis temperature, gasification temperature, and CO2-to-carbon molar ratio improved the CGE.
中文翻译:
常规和微波热解法制备煤焦的CO 2气化动力学和热力学研究
这项研究通过热重分析方法研究了通过两种不同方法(即常规方法和微波辅助热解)制备的四种焦炭的等温CO 2气化。使用最终分析,X射线衍射和扫描电子显微镜检查了炭的物理,化学和结构行为。通过应用收缩的未反应核(SCM)和随机孔(RPM)模型计算动力学参数。而且,char-CO 2通过使用Aspen Plus研究合成气组成和冷气效率(CGE)的热力学性能,进一步模拟了气化。微波诱导的炭具有最大的C / H质量比和最有序的碳结构,但气化反应性最小。动力学分析表明,RPM更适合描述所研究炭的气化转化率和反应速率,其活化能和指数前因子在78.45–194.72 kJ / mol和3.15–102,231.99 s -1之间变化, 分别。另外,在气化期间注意到补偿效果。最后,微波衍生的炭表现出比常规炭更好的热力学性能,最高的CGE和CO摩尔浓度分别为1.30%和86.18%。增加热解温度,气化温度和CO 2-碳摩尔比可以改善CGE。