Gu Chenkai, Jin Jing, Li Ye, Li Ruiyang, Dong Bo
School of Energy and Power Engineering, University of Shanghai for Science and Technology 516 Jungong Road Shanghai 200093 P. R. China
RSC Adv. 2023 Jan 11;13(3):1935-1942. doi: 10.1039/d2ra07853h. eCollection 2023 Jan 6.
Pyrolysis of low-rank coal in CO atmosphere can reduce carbon emissions while comprehensively utilizing coal resources. Based on ReaxFF molecular dynamics (ReaxFF-MD), the pyrolysis processes of low-rank coal in inert and CO atmosphere are simulated. By comparing the evolution of pyrolysis products, the influences of CO on the pyrolysis characteristic and product distribution are analyzed. It is found that CO slightly inhibits the conversion of char to tar in the early stage of pyrolysis. In the later stage, CO significantly promotes the decomposition of char and increases the yield of tar and pyrolysis gas. According to the different bond breaking behaviors of coal molecules, the pyrolysis process can be divided into pyrolysis activation stage, initial pyrolysis stage, accelerated pyrolysis stage and secondary pyrolysis stage. The reforming reaction of CO with alkanes generates free hydrogen radicals, which promotes the cleavage of ether bond, C-C bridge bond and aliphatic C-C bond. Compared with in inert atmosphere, final yield of light tar in CO atmosphere increases from 17.98% to 20.68%. In general, the CO atmosphere helps to improve the tar yield and tar quality of low-rank coal pyrolysis.
低阶煤在CO气氛下热解可减少碳排放，同时实现煤炭资源的综合利用。基于ReaxFF分子动力学（ReaxFF-MD）模拟了低阶煤在惰性气氛和CO气氛下的热解过程。通过比较热解产物的演化，分析了CO对热解特性和产物分布的影响。研究发现，CO在热解初期对煤焦向焦油的转化有轻微抑制作用。在后期，CO显著促进了煤焦的分解，提高了焦油和热解气的产率。根据煤分子不同的断键行为，热解过程可分为热解活化阶段、初始热解阶段、加速热解阶段和二次热解阶段。CO与烷烃的重整反应产生游离氢自由基，促进了醚键、C-C桥键和脂肪族C-C键的断裂。与惰性气氛相比，CO气氛下轻质焦油的最终产率从17.98%提高到20.68%。总体而言，CO气氛有助于提高低阶煤热解的焦油产率和焦油品质。
