热重分析煤焦恒温气化过程中气体切换的影响

doi:10.16085/j.issn.1000-6613.2021-0238

化工进展 ›› 2022, Vol. 41 ›› Issue (1): 166-173.DOI: 10.16085/j.issn.1000-6613.2021-0238

热重分析煤焦恒温气化过程中气体切换的影响

张乾¹(), 向欣宁¹, 梁丽彤¹, 刘建伟¹, 王志青², 房倚天², 黄伟¹()

^1.太原理工大学省部共建煤基能源清洁高效利用国家重点实验室, 山西太原 030024
^2.中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原 030001

收稿日期:2021-01-31 修回日期:2021-03-08 出版日期:2022-01-05 发布日期:2022-01-24
通讯作者: 黄伟
作者简介:张乾（1987—），男，副教授，研究方向为煤气化。E-mail：zhangqian01@tyut.edu.cn。
基金资助:
国家自然科学基金青年项目(21706175);山西省科技厅面上青年基金项目(201901D211049)

Gas switch effect on the isothermal gasification reaction of coal char in thermogravimetric analyser

ZHANG Qian¹(), XIANG Xinning¹, LIANG Litong¹, LIU Jianwei¹, WANG Zhiqing², FANG Yitian², HUANG Wei¹()

^1.State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
^2.State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China

Received:2021-01-31 Revised:2021-03-08 Online:2022-01-05 Published:2022-01-24
Contact: HUANG Wei

摘要/Abstract

摘要：

利用热重分析仪研究恒温煤气化是实验室常用的气化活性评价流程，但该实验中气体切换过程的影响却较少报道。本文以一种煤焦CO₂气化反应为例，通过切换气体与全部采用CO₂气体气化实验对比，分析气体切换步骤对恒温气化实验的影响，并结合在线质谱检测了切换过程中气体逸出规律。研究发现，存在切气步骤时，尽管CO₂可快速扩散至反应区，但由于气体的置换过程并非简单的平推流，导致部分碳的气化是发生在变化着的反应性气体和惰性气体的混合气氛中。这极大地影响了煤焦样品的气化反应速率大小和趋势，进一步影响反应动力学模型的判断和选择，并将导致由此计算所得的活化能受扩散影响而偏低。因此，建议在应用热重分析仪采用气体切换流程研究恒温气固相反应时，应首先对其气体逸出规律进行检测，评估气体切换步骤对整个反应过程的影响，以减小实验误差。

关键词: 煤气化, 热重分析仪, 恒温实验, 气体切换, 动力学分析

Abstract:

Isothermal gasification reaction of coal was often conducted by thermogravimetric analyzer in laboratory, while the gas switch effect in this process was rarely considered. In this paper, a coal char was used to evaluate the effect of the gas switch step on the isothermal gasification experiments by comparing the traditional gas switch process with a newly designed all CO₂ process. The on line mass spectrometry was also used to evaluate the reactive gas evolution behavior in these processes. The results showed that for the gasification reaction with the gas switch process, though the CO₂ could reach to the reaction zone quickly, the coal char was still reacted in the mixture atmosphere of the CO₂ and the initial inert gas for the emission of the inert gas was not an ideal plug flow condition. This greatly affected the gasification rate of the char, further affected the selection of kinetic model, and finally caused the decrease of the calculated activation energy for which was affected by the gas diffusion effect. Therefore, it is suggested that in the study of isothermal gas-solid reactions via thermogravimetric analyser with the gas switch process, the gas evolution behavior should be detected first, and the influence of the gas switch process should be evaluated so as to reduce the errors caused.

Key words: coal gasification, thermogravimetric analyser, isothermal reaction, gas switch effect, kinetic analysis

中图分类号:

TQ546

张乾, 向欣宁, 梁丽彤, 刘建伟, 王志青, 房倚天, 黄伟. 热重分析煤焦恒温气化过程中气体切换的影响[J]. 化工进展, 2022, 41(1): 166-173.

ZHANG Qian, XIANG Xinning, LIANG Litong, LIU Jianwei, WANG Zhiqing, FANG Yitian, HUANG Wei. Gas switch effect on the isothermal gasification reaction of coal char in thermogravimetric analyser[J]. Chemical Industry and Engineering Progress, 2022, 41(1): 166-173.

图/表 9

表1 小龙潭煤与焦的元素分析及工业分析（质量分数）

样品	工业分析（空气干燥基）/%				元素分析（干燥无灰基）/%
样品	水分	灰分	挥发分	固定碳	碳	氢	氧^①	氮	硫
原煤	9.48	9.66	43.33	37.53	64.62	5.80	26.29	2.28	1.01
半焦	1.52	19.57	12.17	66.74	93.57	1.20	1.71	1.93	1.60

表2 小龙潭煤焦中的主要矿物质含量

元素	质量分数/%
Si	1.31
Al	0.94
Fe	2.16
Ca	5.25
Mg	0.16
Ti	0.12
K	0.10
Na	0.10

图1 不同温度下煤焦在两种气化条件下的反应比较

图2 800℃下两种气化方式的气体逸出规律比较

图3 切换气体方式下煤焦在不同温度下的气化反应转化率和反应速率

图4 纯CO2气氛下煤焦在不同终温时的气化反应转化率和反应速率

表3 两种气化方式下煤焦CO2气化反应转化率达到50%所需时间

温度/℃	转化率达到50%所需时间/min
温度/℃	切换气体	纯反应气
700	>120	>120
750	49.1	36.4
800	12.5	10.9
850	4.7	2.9
900	2.3	<2.0

图5 两种气化方式下煤焦气化反应动力学参数拟合

表4 两种气化方式下气化动力学参数计算

气化方式	E_a/kJ?mol^-1	A/min^-1	R²
切换气体	224.6	3.1×10⁹	0.9905
纯反应气	241.4	2.8×10¹⁰	0.9951

参考文献 23

1	田霖, 胡建杭, 刘慧利. 基于热重-红外联用技术分析油酸的热解特性及动力学分析[J]. 化工进展, 2020, 39(S2): 152-161.
	TIAN Lin, HU Jianhang, LIU Huili. Pyrolysis characteristics and kinetics of oleic acid were analyzed by thermogravimetric and infrared spectroscopy[J]. Chemical Industry and Engineering Progress, 2020, 39(S2): 152-161.
2	赵正浩, 向文国, 陈时熠, 等. 基于钴改性的钙基吸附剂污泥富氢气化[J]. 化工进展, 2019, 38(10): 4747-4754.
	ZHAO Zhenghao, XIANG Wenguo, CHEN Shiyi, et al. Performance of cobalt modified calcium sorbents for steam gasification of sewage sludge[J]. Chemical Industry and Engineering Progress, 2019, 38(10): 4747-4754.
3	BREAULT R W. Gasification processes old and new: a basic review of the major technologies[J]. Energies, 2010, 3(2): 216-240.
4	ZHANG Q, LI Q F, ZHANG L X, et al. Preliminary study on co-gasification behavior of deoiled asphalt with coal and biomass[J]. Applied Energy, 2014, 132: 426-434.
5	JING X L, WANG Z Q, YU Z L, et al. Experimental and kinetic investigations of CO₂ gasification of fine chars separated from a pilot-scale fluidized-bed gasifier[J]. Energy & Fuels, 2013, 27(5): 2422-2430.
6	ZHAN X L, ZHOU Z J, WANG F C. Catalytic effect of black liquor on the gasification reactivity of petroleum coke[J]. Applied Energy, 2010, 87(5): 1710-1715.
7	IRFAN M F, USMAN M R, KUSAKABE K. Coal gasification in CO₂ atmosphere and its kinetics since 1948: a brief review[J]. Energy, 2011, 36(1): 12-40.
8	BHATIA S K, PERLMUTTER D D. A random pore model for fluid-solid reactions: ‍Ⅰ‍‍‍. Isothermal, kinetic control[J]. AIChE Journal, 1980, 26(3): 379-386.
9	GOMEZ A, SILBERMANN R, MAHINPEY N. A comprehensive experimental procedure for CO₂ coal gasification: is there really a maximum reaction rate?[J]. Applied Energy, 2014, 124: 73-81.
10	ZENG X, WANG F, WANG Y G, et al. Characterization of char gasification in a micro fluidized bed reaction analyzer[J]. Energy & Fuels, 2014, 28(3): 1838-1845.
11	MORIN M, PÉCATE S, MASI E, et al. Kinetic study and modelling of char combustion in TGA in isothermal conditions[J]. Fuel, 2017, 203: 522-536.
12	OLLERO P, SERRERA A, ARJONA R, et al. Diffusional effects in TGA gasification experiments for kinetic determination[J]. Fuel, 2002, 81(15): 1989-2000.
13	NAREDI P, PISUPATI S V. Interpretation of char reactivity profiles obtained using a thermogravimetric analyzer[J]. Energy & Fuels, 2008, 22(1): 317-320.
14	GÓMEZ-BAREA A, OLLERO P, ARJONA R. Reaction-diffusion model of TGA gasification experiments for estimating diffusional effects[J]. Fuel, 2005, 84(12/13): 1695-1704.
15	GENG P, ZHANG Y, ZHENG Y. Experimental estimate of CO₂ concentration distribution in the stagnant gas layer inside the thermogravimetric analysis (TGA) crucible[J]. Fuel, 2018, 224: 250-254.
16	ZHANG Y, GENG P, ZHENG Y. Exploration and practice to improve the kinetic analysis of char-CO₂ gasification via thermogravimetric analysis[J]. Chemical Engineering Journal, 2019, 359: 298-304.
17	BAI Y H, WANG Y L, ZHU S H, et al. Structural features and gasification reactivity of coal chars formed in Ar and CO₂ atmospheres at elevated pressures[J]. Energy, 2014, 74: 464-470.
18	张林仙, 黄戒介, 房倚天, 等. 中国典型无烟煤焦水蒸气汽化活性及动力学研究[J]. 燃烧科学与技术, 2005, 11(3): 202-207.
	ZHANG Linxian, HUANG Jiejie, FANG Yitian, et al. Reactivity and kinetics of typical Chinese anthracite chars gasification with steam[J]. Journal of Combustion Science and Technology, 2005, 11(3): 202-207.
19	GOMEZ A, MAHINPEY N. Kinetic study of coal steam and CO₂ gasification: a new method to reduce interparticle diffusion[J]. Fuel, 2015, 148: 160-167.
20	KAJITANI S, HARA S, MATSUDA H. Gasification rate analysis of coal char with a pressurized drop tube furnace[J]. Fuel, 2002, 81(5): 539-546.
21	VYAZOVKIN S, WIGHT C A. Isothermal and nonisothermal reaction kinetics in solids: in search of ways toward consensus[J]. The Journal of Physical Chemistry A, 1997, 101(44): 8279-8284.
22	PENG F F, LEE I C, YANG R Y K. Reactivities of in situ and ex situ coal chars during gasification in steam at 1000—1400℃[J]. Fuel Processing Technology, 1995, 41(3): 233-251.
23	向银花, 房倚天, 张守玉, 等. 煤焦部分气化、燃烧集成热重分析研究[J]. 燃料化学学报, 2000, 28(5): 435-438.
	XIANG Yinhua, FANG Yitian, ZHANG Shouyu, et al. Thermogravimetric analysis for coal char partial gasification and combustion[J]. Journal of Fuel Chemistry and Technology, 2000, 28(5): 435-438.

[1]	刘阳, 王云刚, 修浩然, 邹立, 白彦渊. 基于动力学分析的核桃壳最佳炭化工艺[J]. 化工进展, 2023, 42(S1): 94-103.
[2]	张丽宏, 金要茹, 程芳琴. 煤气化渣资源化利用[J]. 化工进展, 2023, 42(8): 4447-4457.
[3]	付春龙, 王松江, 李国智. 煤气化细渣燃烧技术研究进展[J]. 化工进展, 2022, 41(S1): 516-523.
[4]	郭凡辉, 武建军, 张海军, 郭旸, 刘虎, 张一昕. 煤气化细渣陶瓷膜真空脱水试验与数值模拟[J]. 化工进展, 2022, 41(8): 4047-4056.
[5]	吕飞勇, 初茉, 易浩然, 郝焱, 杨彦博, 石旭, 孙星博. 磁性灰粒在不同粒级气化灰渣中的分布特性[J]. 化工进展, 2022, 41(5): 2372-2378.
[6]	张凝凝, 丁华, 高燕, 白向飞, 张昀朋, 孙南翔. 新疆淖毛湖煤中钠在CO₂气化过程的迁移行为[J]. 化工进展, 2022, 41(5): 2348-2355.
[7]	李慧泽, 董连平, 鲍卫仁, 王建成, 樊盼盼, 樊民强. 基于视密度的煤气化渣水介质旋流炭-灰分离[J]. 化工进展, 2021, 40(3): 1344-1353.
[8]	杨小丽, 于戈文, 王延铭, 吴刚强. 煤基液体燃料-电多联产系统元素利用与节能性分析[J]. 化工进展, 2018, 37(S1): 49-56.
[9]	柳康, 许世森, 李广宇, 任永强. 基于整体煤气化联合循环的燃烧前CO₂捕集工艺及系统分析[J]. 化工进展, 2018, 37(12): 4897-4907.
[10]	汪逸, 刘建忠, 李宁, 王双妮, 程军. 煤气化废水成浆特性及添加剂的适配性[J]. 化工进展, 2018, 37(08): 3206-3213.
[11]	吕全伟, 林顺洪, 柏继松, 李长江, 江辽, 李伟. 热重-红外联用(TG-FTIR)分析含油污泥-废轮胎混合热解特性[J]. 化工进展, 2017, 36(12): 4692-4699.
[12]	薛新巧, 冯钰, 靳立军, 胡浩权. 不连沟煤热解半焦燃烧特性研究[J]. 化工进展, 2017, 36(09): 3287-3292.
[13]	侯康, 武建军, 尚晓玲, 张一昕. 热重法研究逐级脱矿对褐煤燃烧特性的影响[J]. 化工进展, 2017, 36(03): 900-908.
[14]	赵代胜. 现代煤化工设计煤质确定方法的探讨[J]. 化工进展, 2016, 35(S1): 75-78.
[15]	曾玺, 王芳, 余剑, 岳君容, 姚梅琴, 许光文. 微型流化床反应分析的方法基础与应用研究[J]. 化工进展, 2016, 35(06): 1687-1697.

热重分析煤焦恒温气化过程中气体切换的影响

Gas switch effect on the isothermal gasification reaction of coal char in thermogravimetric analyser

RichHTML

PDF (PC)

可视化

摘要/Abstract

引用本文

使用本文

图/表 9

参考文献 23

相关文章 15

编辑推荐

Metrics

本文评价