移动床中内构件对煤热解反应过程调控作用

doi:10.16085/j.issn.1000-6613.2020-0892

摘要/Abstract

摘要：

在外热式内构件（多级折流板和多段集气管）移动床反应器内研究了淖毛湖煤的热解特性，并与常规固定床反应器中煤热解行为进行对比，考察了两反应器内的传热速率以及热解温度对产物分布、热解气组成、焦油组成和品质等影响规律。结果表明：在450℃低温热解时，煤颗粒在内构件移动床内的升温时间比固定床缩短了60%以上，内构件具有显著提高反应器内颗粒间传热速率的作用。随着热解温度的升高，热解气中的C₂H₄/C₂H₆和C₃H₆/C₃H₈的比值变大，挥发分的二次反应程度加大，但裂解程度低于固定床。内构件移动床中的焦油产率随温度的升高先增加后降低，在550℃时达到最高为10.8%（质量分数），比固定床增高约28.6%。当热解温度越高时，移动床所产焦油中的沥青质组分含量越低，在750℃时焦油中轻质组分质量分数达到85.17%，脂肪烃含量降低到了28.00%。通过与固定床对比，揭示了内构件（多级折流板和集气管）调控淖毛湖煤热解反应并提高热解焦油产率和品质的作用。

关键词: 移动床, 热解, 传热, 传质, 内构件, 焦油品质, 调控

Abstract:

The pyrolysis characteristics of Naomaohu coal were studied in a moving bed reactor with internals consisting of multi-stage baffles and multi-stage gas outlet lines, and compared with the coal pyrolysis behavior in conventional fixed bed reactor. The effects of heat transfer rate and pyrolysis temperature on products yield, pyrolysis gas composition, and tar composition and quality were investigated in the two reactors. The results showed that the heating time of coal particles in the moving bed reactor with internals was shortened by more than 60% than that of the fixed bed ne during pyrolysis at 450℃, and the internals can significantly enhanced the heat transfer rate of the particles in reactor. With increasing pyrolysis temperature, the ratio of C₂H₄/C₂H₆ and C₃H₆/C₃H₈ in pyrolysis gas increased, the secondary reaction of volatiles increased, but the degree of cracking was lower than that of fixed bed reactor. The tar yield in the moving bed reactor with internals increased first and then decreased with increasing temperature, and reached a maximum mass ratio of 10.8% at 550℃, which was about 28.6% higher than that of the fixed bed one. When the pyrolysis temperature was higher, the content of asphaltene components in the tar produced by the moving bed reactor was lower. At 750℃, the mass ratio of light components in tar reached 85.17% and the content of aliphatic hydrocarbons decreased to 28.00%. Compared with the fixed bed reactor, the role of internals (multi-stage baffles and gas outlet lines) in regulating the pyrolysis reaction of Naomaohu coal and improving the yield and quality of pyrolysis tar was revealed in the moving bed reactor.

Key words: moving bed, pyrolysis, heat transfer, mass transfer, internals, tar quality, regulation

中图分类号:

TQ530.2

周琦, 张旭, 白效言, 张飏, 王岩, 裴贤丰. 移动床中内构件对煤热解反应过程调控作用[J]. 化工进展, 2021, 40(3): 1334-1343.

ZHOU Qi, ZHANG Xu, BAI Xiaoyan, ZHANG Yang, WANG Yan, PEI Xianfeng. Regulation effect of internals in moving bed on coal pyrolysis reaction process[J]. Chemical Industry and Engineering Progress, 2021, 40(3): 1334-1343.

图/表 13

表1 淖毛湖煤的工业分析、元素分析及格金分析

工业分析/%					元素分析（daf）/%					格金分析
M_ad	A_d	V_daf	FC_daf		C	H	N	S	O^*	tar_ad/%
17.72	7.82	50.90	49.10		73.88	5.52	0.98	0.54	19.08	13.1

图1 内构件移动床热解流程1—煤仓；2—折流移动床反应器；3—加热电炉；4—多段集气管；5—折流内构件；6—半焦冷却器；7—螺旋出料器；8—半焦收集罐；9—循环冷却液；10—冷凝器；11—焦油罐；12—去燃烧器；13—丙酮吸收槽；14—湿式气体流量计；15—气相色谱分析仪

图2 固定床热解流程1—控温系统；2—加热系统；3—热电偶；4—电炉；5—固定床；6—气体管路；7—冷却液；8—冷凝器；9—冰水混合物；10~16—丙酮吸收槽；17—脱硫瓶；18—干燥瓶；19—湿式气体流量计；20~22—水箱系统

表2 焦油模拟蒸馏馏分组成

温度范围/℃	馏分名称
<170	轻油
170~210	酚油
210~230	萘油
230~300	洗油
300~360	蒽油
>360	沥青质

图3 物料在不同反应器中的升温曲线

图4 煤在不同反应器中的产物分布规律

表3 不同热解温度下热解气体组成和热值

反应器	气体组成	体积分数/%
反应器	气体组成	450℃	550℃	650℃	750℃
固定床	H₂	8.54	16.10	30.32	37.61
	CH₄	21.44	29.47	27.13	22.53
	CO	16.79	11.51	15.53	16.62
	CO₂	43.12	33.77	19.84	17.00
	C₂～C₃	9.51	8.56	7.05	5.89
	热值/kcal·m^-3	3920	4508	4583	4243
移动床	H₂	10.96	22.08	33.10	43.73
	CH₄	22.51	24.06	19.78	17.30
	CO	10.54	8.04	12.91	22.57
	CO₂	47.29	38.08	28.23	11.76
	C₂～C₃	8.52	7.00	5.30	3.30
	热值/kcal·m^-3	3743	3873	3696	3765

图5 热解气体产率随温度的变化

图6 烷烯烃气体比例随热解温度的变化

图7 焦油模拟蒸馏组成随热解温度的变化

图8 450℃热解所制焦油中的蜡质成分

图9 不同温度下固定床和移动床中热解焦油的GC-MS分析结果

表4 移动床和固定床在不同热解温度下焦油的GC-MS分析

反应器	热解温度/℃	质谱峰面积比/%
反应器	热解温度/℃	单环芳烃	多环芳烃	酚类	脂肪烃类
移动床	450	19.75	6.77	23.66	45.00
	550	20.59	13.80	22.38	38.85
	650	22.97	16.25	20.44	33.62
	750	25.03	20.00	20.20	28.99
固定床	450	12.97	5.91	25.91	45.93
	550	17.10	6.63	22.90	41.70
	650	26.15	10.17	21.19	26.88
	750	28.32	19.61	20.38	20.95

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