Characteristics of oxidation stabilization process of coal pitch based spheres

doi:10.11949/j.issn.0438-1157.20171042

Abstract

Abstract:

Oxidation stabilization is the core process in the preparation of coal pitch based spherical activated carbon. Consequently the understanding of process characteristics and kinetic mechanism is the key to accomplish oxidation process optimization. The effects of particle size range, heating rate and oxidative temperature on oxidation stabilization process were discussed by experiments which used coal pitch spheres as the raw materials. The kinetic parameters and reaction mechanism function were determined. The results show that oxidation stabilization mainly consists of four stages, light component pyrolysis, preliminary oxidation, oxidative weight increment and constant temperature oxidative weightlessness, respectively. After oxidation stabilization, carbon and hydrogen content of coal pitch spheres reduce, oxygen content increases, and surface is much smoother. Reducing the particle size and selecting the appropriate heating rate(0.25-0.5℃·min^-1) and oxidative temperature(275-325℃) are beneficial for oxidation stabilization. The activation energy reaches the minimum values at particle size range of 0.3-0.6 mm, heating rate of 0.5℃·min^-1 and oxidative temperature of 300℃, which are 83.34, 293.19, 302.25 and 357.05 kJ·mol^-1 in every stage.

Key words: coal pitch spheres, oxidation, thermogravimetric analysis, kinetics, activated carbon

摘要：

氧化不熔化过程是煤沥青基球状活性炭制备中的核心工艺，对其过程特性和动力学机理的认识是实现氧化过程工艺优化的关键。本文以煤沥青萃取球为原料，通过实验研究，重点探讨了粒径范围、升温速率和氧化温度对其氧化不熔化过程的影响，并确定氧化动力学参数及其反应机理函数。结果表明：氧化不熔化过程可分为轻组分热解、初步氧化、氧化增重和恒温氧化失重4个阶段。煤沥青球经过氧化不熔化后，C、H含量减少，O含量增加，表面光滑平整。减小粒径并选取合适的升温速率（0.25～0.5℃·min^-1）以及氧化温度（275～325℃），更有利于氧化不熔化快速稳定地进行。粒径范围为0.3～0.6 mm的煤沥青球在升温速率为0.5℃·min^-1、氧化温度为300℃的条件下活化能最小，各个阶段的值分别为83.34、293.19、302.25和357.05 kJ·mol^-1。

关键词: 煤沥青球, 氧化, 热重分析, 动力学, 活性炭

CLC Number:

GUO Yuan, SHAO Yingjuan, ZHONG Wenqi, LI Kaixi. Characteristics of oxidation stabilization process of coal pitch based spheres[J]. CIESC Journal, 2018, 69(1): 499-506.

郭源, 邵应娟, 钟文琪, 李开喜. 煤沥青球的氧化不熔化过程特性[J]. 化工学报, 2018, 69(1): 499-506.

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