Modelling and numerical simulation of n-heptane pyrolysis coking characteristics in a millimetre-sized tube reactor

doi:10.1016/j.combustflame.2018.12.006

	Modelling and numerical simulation of n-heptane pyrolysis coking characteristics in a millimetre-sized tube reactor
	Wang, Xiaohan 1,2; Song, Qianshi 1,3; Wu, Yong 1,3; Li, Xing 1,2; Li, Tao 1,2; Zeng, Xiaojun 1,2
刊名	COMBUSTION AND FLAME
	2019-03-01
卷号	201 页码:44-56
关键词	Coke formation n-heptane pyrolysis Modeling Numerical simulation Tube reactor
ISSN号	0010-2180
DOI	10.1016/j.combustflame.2018.12.006
通讯作者	Wang, Xiaohan(wangxh@ms.giec.ac.cn) ; Li, Xing(lixing@ms.giec.ac.cn)
英文摘要	Based on the optimization of the recently proposed gas phase mechanism for n-heptane pyrolysis, mechanisms for polycyclic aromatic hydrocarbon (PAH) formation and a detailed wall surface reaction, a basic gaseous pyrolysis mechanism with 1127 steps and a simplified surface reaction mechanism with 34 steps were developed, respectively. After performing the detailed estimation and modelling procedures for the surface site density (SDEN) related to the particle diameter, particle density, C/H ratio and other parameters determined by the experimental tests and observations, numerical studies were integrated with the developed coke model to simulate the pyrolysis process and the coking properties in a millimetre sized tube reactor on the Chemkin Pro software platform using a two-dimensional cylindrical shear flow (CSF) module. The prediction values of the pyrolysis product concentration and coking rate at different temperatures were compared with the experimental data, and agreement was obtained. Under pyrolysis conditions of an n-heptane inlet flow rate of 0.5 ml/min, an operating pressure of 1.0 MPa and a furnace temperature of 973-1073 K, the research results showed that the hydrogen abstraction reaction, as the first and key step of coke formation, is easily affected by gaseous diffusion. As the temperature and particle diameter increase, the inhibition of diffusion becomes stronger. Among all the considered radicals, the abstraction ability of the H radical is the strongest, and it is easily restricted by diffusion. The presence of abundant radicals such as CH3, C2H3, and C3H5 at low temperatures can compensate for this limitation. For the unsaturated species addition reactions, the calculation results showed that the addition of olefins, alkynes, diolefins and aromatic hydrocarbons occurs in sequence with an increase in residence time. With increasing temperature, the addition contributions of. olefins,such as C2H4, and C3H6 gradually weaken, while those of small molecule aromatic hydrocarbons such as benzene (A1) and styrene (A1C(2)H(3)) remarkably increase. Alkynes and diolefins, such as C2H2 and C3H4, have low concentrations under the experimental conditions, and their addition contributions are very low and can be ignored. Due to the addition of unsaturated species, the concentration of H-2 in the gas phase is significantly improved. The modeling work can predict the coke formation characteristics and quantitatively evaluate the change in the coke formation rate, which is helpful for explaining the intrinsic thermal pyrolysis coking mechanism in a round tube, such as the regenerative cooling system of supersonic engines, among others. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
资助项目	Transformational Technologies for Clean Energy and Demonstration, the Strategic Priority Research Program of the Chinese Academy of Sciences[XDA 21060102] ; Training Program of the Major Research Plan of the National Natural Science Foundation of China[91441127]
WOS关键词	COUNTERFLOW DIFFUSION FLAMES ; LOW-TEMPERATURE COMBUSTION ; REACTION-MECHANISM ; SOOT PARTICLES ; COKE FORMATION ; NASCENT SOOT ; FUEL ; OXIDATION ; PRESSURE ; SURFACE
WOS研究方向	Thermodynamics ; Energy & Fuels ; Engineering
语种	英语
出版者	ELSEVIER SCIENCE INC
WOS记录号	WOS:000458094700005
资助机构	Transformational Technologies for Clean Energy and Demonstration, the Strategic Priority Research Program of the Chinese Academy of Sciences ; Training Program of the Major Research Plan of the National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.giec.ac.cn/handle/344007/25045]
专题	中国科学院广州能源研究所
通讯作者	Wang, Xiaohan; Li, Xing
作者单位	1.Chinese Acad Sci, Guangzhou Inst Energy Convers, Guangzhou 510640, Guangdong, Peoples R China 2.Chinese Acad Sci, Key Lab Renewable Energy, Guangzhou 510640, Guangdong, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Wang, Xiaohan,Song, Qianshi,Wu, Yong,et al. Modelling and numerical simulation of n-heptane pyrolysis coking characteristics in a millimetre-sized tube reactor[J]. COMBUSTION AND FLAME,2019,201:44-56.
APA	Wang, Xiaohan,Song, Qianshi,Wu, Yong,Li, Xing,Li, Tao,&Zeng, Xiaojun.(2019).Modelling and numerical simulation of n-heptane pyrolysis coking characteristics in a millimetre-sized tube reactor.COMBUSTION AND FLAME,201,44-56.
MLA	Wang, Xiaohan,et al."Modelling and numerical simulation of n-heptane pyrolysis coking characteristics in a millimetre-sized tube reactor".COMBUSTION AND FLAME 201(2019):44-56.