Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles under pressurized and fluidized conditions

doi:10.1007/s11705-018-1725-8

Frontiers of Chemical Science and Engineering

2019, Vol. 13

Issue (2): 415-426 https://doi.org/10.1007/s11705-018-1725-8

本期目录

Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles under pressurized and fluidized conditions

Xuantao Wu, Jie Wang(

)

Department of Chemical Engineering for Energy, Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai 200237, China

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Abstract：

Catalytic steam gasification of fine coal char particles was carried out using a self-made laboratory reactor to determine the intrinsic kinetics and external diffusion under varying pressures (0.1–0.5 MPa) and superficial gas flow velocities (GFVs) of 13.8– 68.8 cm∙s⁻¹. In order to estimate the in-situ gas release rate at a low GFV, the transported effect of effluent gas on the temporal gasification rate pattern was simulated by the Fluent computation and verified experimentally. The external mass transfer coefficients (k_ma_m) and the effectiveness factors were determined at lower GFVs, based on the intrinsic gasification rate obtained at a high GFV of 55.0 cm∙s^–1. The k_ma_m was found to be almost invariable in a wider carbon conversion of 0.2–0.7. The variations of k_ma_m at a median carbon conversion with GFV, temperature and pressure were found to follow a modified Chilton-Colburn correlation: $S h = 0.311 Re ⁡ 2.83 S c 13 (P P 0) − 2.07$ (0.04<Re<0.19), where P is total pressure and P₀ is atmospheric pressure. An intrinsic kinetics/external diffusion integrating model could well describe the gasification rate as a function of GFV, temperature and pressure over a whole gasification process.

Key words： coal char catalytic steam gasification pressure kinetics diffusion

收稿日期: 2018-01-23 出版日期: 2019-05-22

Corresponding Author(s): Jie Wang

引用本文:

. [J]. Frontiers of Chemical Science and Engineering, 2019, 13(2): 415-426.
Xuantao Wu, Jie Wang. Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles under pressurized and fluidized conditions. Front. Chem. Sci. Eng., 2019, 13(2): 415-426.

链接本文:

https://academic.hep.com.cn/fcse/CN/10.1007/s11705-018-1725-8
https://academic.hep.com.cn/fcse/CN/Y2019/V13/I2/415

Fig.1

Fig.2

Fig.3

Fig.4

Exp. no.	Total pressure /MPa	Flow rate /(cm?s^–1)	$Δ r 0.2 / r 0.2$ /%	$Δ r 0.5 / r 0.5$ /%	$Δ r 0.8 / r 0.8$ /%	$Δ r ¯ / r ¯$ /%
1^a)	0.5	55.0	0.65	1.17	5.62	0.35
2	0.1	68.8	3.75	0.59	2.06	0.32
3	0.1	55.0	4.56	0.10	1.13	0.92
4	0.1	41.3	5.86	1.94	4.88	2.80
5	0.1	27.5	5.46	2.11	5.60	2.82
6	0.1	13.8	4.02	5.65	10.06	7.34
7	0.5	13.8	4.97	9.69	34.15	14.50
8	1.0	13.8	3.21	12.68	54.08	19.76
9	1.5	13.8	6.02	11.60	44.65	21.36
10	2.0	13.8	9.81	11.97	56.65	25.88

Tab.1

Fig.5

Fig.6

Fig.7

Fig.8

Physical variable	Total pressure /MPa
Physical variable	0.1	0.2	0.4	0.5
$v$ /(10^–3 m²?s^–1)	0.1341	0.0671	0.0335	0.0268
$D lam$ /(10^–3 m²?s^–1)	0.2128	0.1064	0.0532	0.0426
$D tur$ /(10^–3 m²?s^–1)	0.0214	0.0215	0.0237	0.0254
$D eff$ /(10^–3 m²?s^–1)	0.2343	0.1279	0.0769	0.0680
$C s,b$ /(mol?m^–3)	4.7020	9.4040	18.8081	23.5101
$d p$ /(10^–3 m)	0.0254	0.0254	0.0254	0.0254
$a t$ /(m²?mol^–1)	1.8289	1.8289	1.8289	1.8289
$ε$	0.6962	0.6962	0.6962	0.6962

Tab.2

Fig.9

Fig.10

Fig.11

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