微型流化床中萘裂解生成小分子气体的反应动力学研究

doi:10.11949/0438-1157.20201738

摘要/Abstract

摘要：

气化是煤、生物质以及其他含碳燃料高值化利用的有效途径之一。为了考察气化过程中焦油的反应转化特性，选取萘作为焦油模型化合物，以流化催化裂化（fluid catalytic cracking，FCC）催化剂及褐煤热解焦作为接触裂解载体，利用微型流化床考察流化条件下萘催化裂解反应规律，并采用Friedman法和积分法计算萘裂解生成CH₄和H₂等典型气体组分的动力学参数。结果表明，FCC催化剂与褐煤焦均对萘裂解有明显的催化效果，褐煤焦用于萘裂解的反应活化能整体数值低于FCC催化剂。FCC催化剂裂解萘生成H₂符合三维扩散（球形对称）模型，生成CH₄符合成核与生长（n=2/3）模型。相应地，褐煤焦裂解萘反应生成H₂和CH₄分别采用收缩几何形状（圆柱形对称）和三维扩散（圆柱形对称）具有较好的拟合度。

关键词: 微型流化床, 萘, 催化裂解, 反应动力学

Abstract:

Gasification is one of the effective ways for high-value utilization of coal, biomass and other carbon-containing fuels. To investigate the reaction characteristics of tar during gasification, naphthalene was selected as the tar model compound and converted in a micro fluidized bed by using fluid catalytic cracking (FCC) catalyst and lignite coke as contact cracking carrier. The cracking kinetics of naphthalene in terms of CH₄ and H₂ generation were calculated by Friedman method and integral method respectively. The results show that both FCC catalyst and lignite coke had obvious catalytic effect on naphthalene. When lignite coke was used for naphthalene cracking, the overall reaction activation energy was lower than that of FCC catalyst. The catalytic cracking of naphthalene over FCC catalyst was close to three-dimensional diffusion (spherical symmetry) and nucleation and growth (n=2/3) models, while the three-dimensional diffusion (cylindrical symmetry) and contraction geometry (cylindrical symmetry) models had a good fitting degree for naphthalene cracking using lignite coke.

Key words: micro fluidized bed, naphthalene, catalytic cracking, reaction kinetics

中图分类号:

TQ 546

张玉明, 纪德馨, 朱翰文, 万利锋, 张炜, 温宏炎, 岳君容. 微型流化床中萘裂解生成小分子气体的反应动力学研究[J]. 化工学报, 2021, 72(5): 2604-2615.

ZHANG Yuming, JI Dexin, ZHU Hanwen, WAN Lifeng, ZHANG Wei, WEN Hongyan, YUE Junrong. Reaction kinetics of naphthalene cracking into small molecule gas in a micro fluidized bed[J]. CIESC Journal, 2021, 72(5): 2604-2615.

图/表 14

参考文献 33

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样品	工业分析/%(质量分数)				元素分析/%(质量分数)
样品	V_ad	M_ad	A_ad	FC_ad*	N_d	C_d	H_d	S_d	O_d*
LC	4.12	2.92	25.59	67.37	0.94	69.32	1.49	0.80	1.09

样品	工业分析/%(质量分数)				元素分析/%(质量分数)
样品	V_ad	M_ad	A_ad	FC_ad*	N_d	C_d	H_d	S_d	O_d*
LC	4.12	2.92	25.59	67.37	0.94	69.32	1.49	0.80	1.09

LC ash/%（质量分数）
TiO₂	MgO	Al₂O₃	SiO₂	SO₃	K₂O	CaO	Fe₂O₃	Others
1.19	3.94	8.56	12.63	31.65	0.54	34.46	6.52	0.51
FCC-C/%（质量分数）
V₂O₅	P₂O₅	Al₂O₃	SiO₂	Na₂O	K₂O	NiO	Fe₂O₃	Others
1.09	1.38	47.87	47.34	0.36	0.20	0.52	0.51	0.73

LC ash/%（质量分数）
TiO₂	MgO	Al₂O₃	SiO₂	SO₃	K₂O	CaO	Fe₂O₃	Others
1.19	3.94	8.56	12.63	31.65	0.54	34.46	6.52	0.51
FCC-C/%（质量分数）
V₂O₅	P₂O₅	Al₂O₃	SiO₂	Na₂O	K₂O	NiO	Fe₂O₃	Others
1.09	1.38	47.87	47.34	0.36	0.20	0.52	0.51	0.73

样品	比表面积/(m²/g)			孔体积/(cm³/g)			平均孔径D_a/nm
样品	A_total	A_micro	A_meso	V_total	V_mico	V_meso	平均孔径D_a/nm
LC	214.0	175.5	38.5	0.5319	0.1043	0.4276	9.94
FCC-C	106.8	64.6	42.2	0.5716	0.0432	0.5329	24.97