不同稀释剂条件下甲烷非催化部分氧化数值模拟

杨梦如; 仇鹏; 许建良; 代正华; 王辅臣

doi:10.14135/j.cnki.1006-3080.20220430001

不同稀释剂条件下甲烷非催化部分氧化数值模拟

doi: 10.14135/j.cnki.1006-3080.20220430001

杨梦如^1,,
仇鹏¹,
许建良¹,
代正华^{1, 2, ,},
王辅臣¹

1.
华东理工大学资源与环境工程学院, 上海市煤气化工程技术研究中心, 上海 200237
2.
新疆大学化工学院, 乌鲁木齐 830046

基金项目: 上海科技创新行动计划(21DZ1209003)；上海市优秀技术带头人项目(19XD1434800)；国家自然科学基金项目(21776087)

详细信息

作者简介:
杨梦如（1995—），女，山东济宁人，硕士生，主要研究方向为天然气非催化部分氧化。E-mail：1635262630@qq.com

通讯作者:
代正华，E-mail：chinadai@ecust.edu.cn

中图分类号: TE646
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出版历程
- 收稿日期: 2022-04-30
- 网络出版日期: 2022-07-14

Numerical Simulation of Non-catalytic Partial Oxidation of Methane Based on Different Diluents

1.
Shanghai Engineering Technology Research Center of Coal Gasification, School of resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
2.
School of Chemical Engineering, Xinjiang University, Urumqi 830046, China

摘要

摘要: 以工业装置O₂/CH₄体积比为0.69操作条件为基础，使用ANSYS Fluent16.1开展数值模拟，采用基于雷诺平均方程(RANS) 的 Realizable k-ε 湍流模型、涡耗散概念 (EDC) 模型与 GRI3.0 详细化学反应机理的耦合来模拟炉内的湍流燃烧与化学反应过程。考察了三种稀释剂(N₂、H₂O、CO₂)对转化炉内的温度、自由基(OH、CH₂O)分布以及炉膛火焰反应区分布的影响。结果表明：N₂和H₂O稀释对转化炉内温度、自由基及反应区分布的影响差别很小，CO₂稀释下的影响最为显著。在CO₂稀释下，炉膛内的最高火焰温度降低了约50 K；OH和CH₂O自由基峰值分别降低了大约33%和24.5%。此外，CO₂稀释的三种不同效应对转化炉内温度和自由基分布的影响大小依次为：稀释效应>热效应>化学效应。
- 非催化部分氧化 /
- 稀释剂 /
- CO₂稀释 /
- 火焰温度 /
- 化学效应
Abstract: The high temperature flame in the reformer of non-catalytic partial oxidation (NC-POX) of methane under pure oxygen atmosphere will affect the safe and stable operation of the actual industrial plant. Adding diluent to dilute pure oxygen in the reaction system can improve the temperature distribution and flame structure of the reformer. An O₂/CH₄ ratio of approximately 0.69 was typically used when NC-POX reformers were used industrially, numerical modelling was conducted using ANSYS Fluent 16.1 commercial simulation software, with a Realizable k–ε turbulence model considered for Reynolds-averaged Navier-Stokes (RANS) model, the Eddy Dissipation Concept (EDC) model coupled with GRI3.0 chemical reaction mechanism was suitable for simulating turbulent combustion and chemical reaction processes in the reformer. This study investigates the effect of three diluent (N₂, CO₂, H₂O) on the distribution of temperature, radicals (OH、CH₂O) and flame reaction zone. Results indicate that the effects of N₂ and H₂O dilution on the temperature, radicals and flame reaction zone distribution are basically indistinguishable, and the effect of CO₂ dilution is the most significant. The increasing of CO₂ content decreases the peak temperature by about 50K and peak values of OH and CH₂O radicals decreased by about 33% and 24.5%, respectively. In addition, three effects of CO₂ dilution on the temperature and radicals distribution in the reformer are in the order of dilution effect>thermal effect>chemical effect. Therefore, using the diluent CO₂ to improve the temperature distribution of the reformer system not only realizes the effective adjustment of the H₂/CO ratio of the syngas, but also provides support for the flame control in a high-temperature reducing atmosphere.
- non-catalytic partial oxidation /
- diluents /
- CO₂ dilution /
- flame temperature /
- chemical effect

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图 1 天然气非催化部分氧化炉结构示意图

Figure 1. Structure diagram of the POX reformer

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图 2 喷嘴结构示意图

Figure 2. Structure diagram of the burner

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图 3 表1工况1不同密度网格的温度(a)和速度(b)的模拟结果比较

Figure 3. Comparison of simulation results of temperature (a) and velocity (b) for different density grids of case1 in table 1

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图 4 模拟与实验结果的对比

Figure 4. The comparison of simulation and experimental data results

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图 5 不同稀释剂下的温度(a)和X_O2 (b)的分布比较

Figure 5. Temperature (a) and X_O2(b) profiles in reformer under different diluents

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图 6 不同稀释剂条件下的炉内的X_OH分布

Figure 6. X_OH profiles under different diluents

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图 7 不同稀释剂条件下的OH摩尔分数(a)和CH₂O摩尔分数(b)的轴向分布

Figure 7. X_OH (a) and X_CH2O (b) profiles under different diluents

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图 8 CO₂的不同效应对炉内温度分布(a)及温度峰值(b)的影响

Figure 8. Different effects of CO₂ on the temperature profile (a) and peak value of temperature (b) in the reformer

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图 9 不同条件下的自由基(H、O、OH、CH₂O)摩尔分数的对比

Figure 9. Comparison of the mole fractions of different radicals (H, O, OH, CH₂O) under different conditions

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图 10 CO₂的化学效应在不同稀释程度下的变化曲线

Figure 10. The change curve of the chemical effect of CO₂ under different dilution degrees

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表 1 模拟工况的设定

Table 1. Simulation conditions

Case	O₂ Flow/(L•s⁻¹)	$ \varphi $_CO2 /%	$ \varphi $_N2 /%	$ \varphi $_H2O /%	CH₄ Flow/(L•s⁻¹)	O₂/CH₄ Ratio
1	0.177	0	0	0	0.255	0.69
1*	0.141	0	0	0	0.204	0.69
2	0.177	30	0	0	0.255	0.69
3	0.177	0	30	0	0.255	0.69
4	0.177	0	0	30	0.255	0.69

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表 2 三种稀释剂条件下的出口气体组成

Table 2. Outlet gas composition under three diluent conditions

	Species volume fractions
	H₂	H₂O	CH₄	CO	CO₂	N₂	H₂/CO
N₂ dilution	0.3877	0.2300	0.0297	0.1918	0.0382	0.0738	2.02
H₂O dilution	0.3974	0.2914	0.0314	0.1870	0.0463	0.0008	2.13
CO₂ dilution	0.3652	0.2589	0.0361	0.2390	0.0598	0.0008	1.53
No dilution	0.4460	0.2216	0.0210	0.2293	0.0359	0.0016	1.95

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