停留时间对低阶煤快速热解产物分布、组成及结构的影响

doi:10.16085/j.issn.1000-6613.2018-0348

摘要/Abstract

摘要：

利用自由落下床反应器，研究了快速热解过程中颗粒停留时间对神木烟煤和内蒙古褐煤热解过程的影响,并进一步延长快速热解新生半焦停留时间考察了半焦的二次热解过程。结果表明，快速热解过程中颗粒停留时间的增加促进了挥发分的析出，神木烟煤热解焦油产率持续增加，内蒙古褐煤热解焦油产率先增加后降低。停留时间对焦油品质有明显影响，随时间的增加，两种煤快速热解轻质油中苯类和苯酚类单环化合物含量均先增加后降低，进一步延长停留时间，多环芳烃化合物含量显著增加。快速热解半焦的二次热解主要促进了气体的生成，焦油产率和组成无明显变化，挥发分的进一步析出促进了半焦微孔的发展，神木烟煤和内蒙古褐煤半焦比表面积均显著增加。这表明，在以高品质焦油为目标产品时，采用较低的反应温度、较适宜的煤粒停留时间的快速热解工艺条件是可取的。

关键词: 煤, 快速热解, 停留时间, 半焦, 焦油

Abstract:

The fast pyrolysis of Shenmu bituminous coal (SM) and Inner Mongolia lignite (NM) at different residence time in a free fall reactor is investigated. The secondary pyrolysis of the nascent char from the fast pyrolysis is also studied under a controlled temperature. The results show that with the increase of the residence time, the devolatilizations of both coals are enhanced. The tar yield from SM pyrolysis increases while that of NM pyrolysis increases firstly and then decreases. In addition, the residence time has significant influence on tar quality. With the increase of residence time, the benzenes and phenols in the light tars from both coals increase at first and then decrease, and longer residence time leads to obvious generation of polycondensed aromatics. The secondary pyrolysis of char produces more gaseous product, while the tar yield and its composition change little. Nevertheless, the micropores of char are developed. These results indicate that the fast pyrolysis of coal with suitable residence time of coal at moderate temperatures is advisable for producing high quality tar.

Key words: coal, fast pyrolysis, residence time, char, tar

中图分类号:

TQ 536.1

张俊杰,徐绍平,王光永,杨怀天. 停留时间对低阶煤快速热解产物分布、组成及结构的影响[J]. 化工进展, 2019, 38(03): 1346-1352.

Junjie ZHANG,Shaoping XU,Guangyong WANG,Huaitian YANG. Effect of residence time on distribution, composition and structure of products derived from fast coal pyrolysis[J]. Chemical Industry and Engineering Progress, 2019, 38(03): 1346-1352.

图/表 9

参考文献 23

1	王建国，赵晓红 . 低阶煤清洁高效梯级利用关键技术与示范[J]. 中国科学院院刊，2012，27(3)：382-388.
	WANG Jianguo , ZHAO Xiaohong . Demonstration of key technologies for clean and efficient utilization of low-rank coal [J]. Bulletin of Chinese Academy of Sciences, 2012, 27(3): 382-388.
2	张梦蝶，王泽，张喜文，等 . 烟煤固体热载体低温快速热解实验研究[J]. 过程工程学报，2010，10(3)：530-535.
	ZHANG Mengdie , WANG Ze , ZHANG Xiwen , et al . Experimental study on fast pyrolysis of bituminous coals by solid heat carrier at low temperature [J]. The Chinese Journal of Process Engineering, 2010, 10(3): 530-535.
3	MIURA K . Mild conversion of coal for producing valuable chemicals [J]. Fuel Processing Technology, 2000, 62(2): 119-135.
4	TROMP P J J , MOULIGN J . Slow and rapid pyrolysis of coal[M]// YÜRÜM Y. New trends in coal science. Netherlands: Springer 1988: 305-338.
5	曲旋，张荣，孙东凯，等 . 固体热载体热解霍林河褐煤实验研究[J]. 燃料化学学报，2011，39(2)：85-89.
	QU Xuan , ZHANG Rong , SUN Dongkai , et al . Experiment study on pyrolysis of Huolinhe lignite with solid heat carrier [J]. Journal of Fuel Chemistry and Technology, 2011, 39(2): 85-89.
6	MORGAN T J , KANDIYOTI R . Pyrolysis of coals and biomass: analysis of thermal breakdown and its products [J]. Chemical Reviews, 2013, 114(3): 1547-1607.
7	邓靖，李文英，李晓红，等 . 橄榄石基固体热载体影响褐煤热解产物分布的分析[J]. 燃料化学学报，2013，41(8)：937-942.
	DENG Jing , LI Wenying , LI Xiaohong , et al . Product distribution of lignite pyrolysis with olivine-based solid heat carrier [J]. Journal of Fuel Chemistry and Technology, 2013, 41(8): 937-942.
8	CHEN Z H , SHI Y , LAI D G , et al . Coal rapid pyrolysis in a transport bed under steam-containing syngas atmosphere relevant to the integrated fluidized bed gasification [J]. Fuel, 2016, 176: 200-208.
9	WANG J G , LU X S , YAO J X , et al . Experimental study of coal topping process in a downer reactor [J]. Ind. Eng. Chem. Res., 2005, 44(3): 463-470.
10	崔丽杰 . 煤热解过程中产物组成和官能团转化的研究[D]. 北京：中国科学院过程工程研究所，2005.
	CUI Lijie . Product distribution and functional group conversion in coal pyrolysis[D]. Beijing: Institute of Process Engineering, Chinese Academy of Sciences, 2005.
11	申春梅，吴少华，林伟刚，等 . 煤拔头中低温快速热解烟煤半焦的孔隙结构[J]. 过程工程学报，2010，10(3): 522-529.
	SHEN Chunmei , WU Shaohua , LIN Weigang , et al . Pore structure of low temperature and fast pyrolysis bituminous semi-char from coal topping process [J]. The Chinese Journal of Process Engineering, 2010, 10(3): 522-529.
12	陈兆辉，高士秋，许光文，等 . 煤热解过程分析与工艺调控方法[J]. 化工学报，2017，68(10)：3693-3707.
	CHEN Zhaohui , GAO Shiqiu , XU Guangwen , et al . Analysis and control methods of coal pyrolysis process [J]. CIESC Journal, 2017, 68(10): 3693-3707.
13	刘振宇 . 煤化学的前沿与挑战：结构与反应[J]. 中国科学：化学，2014，44(9)：1431-1439.
	LIU Zhenyu . Advancement in coal chemistry: structure and reactivity [J]. Scientia Sinica Chimica, 2014, 44(9): 1431-1439.
14	ZHANG J J , QUAN C , QIU Y J , et al . Effect of char on co-pyrolysis of biomass and coal in a free fall reactor [J]. Fuel Processing Technology, 2015, 135: 73-79.
15	WEI L G , ZHANG L , XU S P . Effects of feedstock on co-pyrolysis of biomass and coal in a free-fall reactor [J]. Journal of Fuel Chemistry and Technology, 2011, 39(10): 728-734.
16	SUGAWARA T , SUGAWARA K , SATO S , et al . Characteristics of rapid hydropyrolysis of coals in a free fall pyrolyser [J]. Fuel, 1990, 69(9): 1177-1185.
17	李世光 . 煤热解和煤与生物质共热解过程中硫的变迁[D]. 大连：大连理工大学，2006.
	LI Shiguang . Desulufrization of coal during pyrolysis and copyrolysis with biomass [D]. Dalian: Dalian University of Technology, 2006.
18	陈昭睿 . 煤热解过程中热解气停留时间对热解产物的影响[D]. 杭州：浙江大学，2015.
	CHEN Zhaorui . Influence of gas residence time on product distribution of coal pyrolysis [D]. Hangzhou: Zhejiang University, 2015.
19	陈一凡 . 流化床中气体停留时间对煤热解过程释放产物的影响[D]. 杭州：浙江大学，2017.
	CHEN Yifan . Effects of gas residence time on the products of coal pyrolysis in fluidized bed [D]. Hangzhou: Zhejiang University, 2017.
20	俞乔尼，张越，杨帆，等 . 褐煤氧化前后的特性分析[J]. 化工进展，2017，36(s1)：175-179.
	YU Qiaoni , ZHANG Yue , YANG Fan , et al . Characteristic analysis for the lignite before and after oxidized [J]. Chemical Industry and Engineering Progress, 2017, 36(s1): 175-179.
21	HAN J Z , WANG X D , YUE J R , et al . Catalytic upgrading of coal pyrolysis tar over char-based catalysts [J]. Fuel Processing Technology, 2014, 122(1): 98-106.
22	朱学栋，朱子彬，韩崇家，等 . 煤的热解研究Ⅲ. 煤中官能团与热解生成物[J]. 华东理工大学学报，2000，26(1)：14-17.
	ZHU Xuedong , ZHU Zibin , HAN Chongjia , et al . Fundamental study of coal pyrolysis: Functional group and pyrolysis products[J]. J. East China Univ. Sci. Technol., 2000, 26(1): 14-17.
23	丘纪华 . 煤粉在热分解过程中比表面积和孔隙结构的变化[J]. 燃料化学学报，1994, 22(3): 316-320.
	QIU Jihua . Variation of surface area and pore structure of pulverized coal during pyrolysis [J]. Journal of Fuel Chemistry and Technology, 1994, 22(3): 316-320.

样品	工业分析(质量分数)/%			元素分析(质量分数)/%
样品	M _ad	A _d	V _daf	C_daf	H_daf	N_daf	O_daf ^①	S_t,d
SM	5.16	6.73	35.38	77.53	4.70	1.02	15.34	1.32
NM	12.26	12.65	41.17	69.83	3.96	0.88	21.18	3.63

样品	工业分析(质量分数)/%			元素分析(质量分数)/%
样品	M _ad	A _d	V _daf	C_daf	H_daf	N_daf	O_daf ^①	S_t,d
SM	5.16	6.73	35.38	77.53	4.70	1.02	15.34	1.32
NM	12.26	12.65	41.17	69.83	3.96	0.88	21.18	3.63

L/m	t _R/s
L/m	SM	NM
1.05	1.0	1.1
1.40	1.4	1.5
1.75	1.8	1.9
1.90	1.9	2.1

L/m	t _R/s
L/m	SM	NM
1.05	1.0	1.1
1.40	1.4	1.5
1.75	1.8	1.9
1.90	1.9	2.1

样品		比表面积 /m²·g^?1	微孔孔容 /cm³·g^?1	总孔孔容 /cm³·g^?1	平均孔径 /nm
SM	原煤	11.8	0.0042	0.017	5.95
	1.0s半焦	0.5	0.0002	0.004	34.58
	1.4s半焦	0.5	0.0002	0.004	31.12
	1.8s半焦	0.6	0.0001	0.003	23.02
	1.9s半焦	0.6	0.0001	0.003	22.56
	15min半焦^①	6.8	0.0029	0.009	5.17
NM	原煤	0.9	0.0003	0.006	27.61
	1.1s半焦	2.1	0.0009	0.01	18.81
	1.5s半焦	3.4	0.0014	0.01	11.45
	1.9s半焦	5.4	0.0024	0.01	7.67
	2.1s半焦	5.8	0.0024	0.008	5.43
	15min半焦^①	143.1	0.0528	0.096	2.68