Experiments on burning low calorific value H2/CO in the porous media: effect of porous morphology and structure

doi:10.11949/0438-1157.20250444

Abstract

Abstract:

To investigate the impact of the porous media structural characteristics on combustion enhancement, a new structural parameter tortuosity was introduced on the basis of porosity and pore size to characterize the structural properties of porous media, porosity and pore size. Experimental studies were conducted to explore the combustion stability of low calorific value H₂/CO mixture within porous media under varying structural parameter conditions. The results show that porous media can improve the upper limit of stable combustion, broaden the lean combustion limit and reduce pollutant emissions. In contrast to the non-monotonic influence exhibited by porosity and pore size on combustion stability, the effect of tortuosity on combustion stability in the experiment shows a monotonic change trend, and the high tortuosity structure has a stronger combustion enhancement effect. By optimizing the structural parameters, the flame stability in porous media can be significantly improved. Additionally, the three structural parameters exhibit different impacts depending on the combustion states. In scenarios involving high power density combustion, a structure with high porosity contributes to the reduction of CO emissions, whereas for ultra-lean combustion, a structure with high tortuosity and low porosity is recommended.

Key words: porous media combustion, porous morphology, tortuosity, low calorific syngas

摘要：

为了研究多孔介质结构特征对燃烧强化作用的影响，在孔隙率和孔径基础上，引入新的结构参数弯曲度表征多孔介质的形貌结构特性，并对不同结构参数条件下多孔介质中低热值H₂/CO混合气的燃烧稳定性开展实验研究。结果表明，多孔介质可提高稳燃上限，拓宽贫燃极限并降低污染物排放。与孔隙率和孔径对燃烧稳定性的非单调影响特性不同，实验中弯曲度对燃烧稳定性的影响呈单调变化趋势，高弯曲度结构具有更强的燃烧增强效果。通过优化结构参数，可以扩大多孔介质燃烧的稳燃范围。此外，三个结构参数针对不同的燃烧状态也表现出不同的影响，对于高功率密度燃烧，采用高孔隙率结构可以实现更低的CO排放，对于极贫燃燃烧则应采用高弯曲度、低孔隙率的结构。

关键词: 多孔介质燃烧, 多孔介质形貌, 弯曲度, 低热值气体

CLC Number:

TK 16

Liang LI, Yang ZHANG, Hai ZHANG. Experiments on burning low calorific value H₂/CO in the porous media: effect of porous morphology and structure[J]. CIESC Journal, 2025, 76(10): 5351-5361.

李亮, 张扬, 张海. 多孔介质形貌与结构对低热值H₂/CO混合气燃烧特性影响的实验研究[J]. 化工学报, 2025, 76(10): 5351-5361.

Figures/Tables 16

Fig.1 Experimental system of porous media combustion

Fig.2 Schematic of the porous media zone (a) and the flame pictures with and without porous media [(b)—(e)]

Fig.3 Radial (a) and axial (b) temperature distribution of porous media combustion

Table 1 Structural parameters of the PM used

实验编号	孔隙率ε	平均孔径d_m/mm	弯曲度τ	单棒直径d_r/mm	阵列数量N_r
PM1	0.974	3.11	1.0	0.6	182
PM2	0.953	2.93	1.0	0.8	182
PM3	0.927	2.16	1.0	0.8	285
PM4	0.927	2.71	1.0	1.0	182
PM5	0.927	3.25	1.0	1.2	126
PM6	0.927	6.78	1.0	2.5	29
PM7	0.895	2.71	1.0	1.2	182
PM8 (泡沫结构)	0.830	3.45	1.19	—	—
PM9 (直孔蜂窝)	0.439	3.92	1.0	—	—
PM10 (颗粒堆积)	0.438	5.00	1.40	—	—

Table 2 Operating conditions

功率密度Q_B/(MW/m³)	当量比ϕ	表观气体流速U_D/(cm/s)
0.3	0.35	17.2
	0.30	19.7
	0.25	23.2
	0.20	28.5
0.6	0.35	34.4
	0.30	39.4
	0.25	46.4
	0.20	56.9
0.8	0.35	46.4
	0.30	53.0
	0.25	62.5
	0.20	76.7

Fig.4 Stability diagrams of three different porous media structure

Fig.5 Flame stability range with different porosity (ϕ = 0.20)

Fig.6 Flame stability range with different mean pore diameter (ϕ = 0.20)

Fig.7 Flame stability range with different tortuosity (ϕ = 0.20)

Fig.8 Lean-burn limit with different porosity (QB = 0.3 MW/m3)

Fig.9 Lean-burn limit with different mean pore diameter (QB = 0.3 MW/m3)

Fig.10 Lean-burn limit with different tortuosity (QB = 0.3 MW/m3)

Fig.11 CO emission with different porosity (QB = 0.3 MW/m3)

Fig.12 Low CO emission ranges with different porosity

Fig.13 Low CO emission ranges with different mean pore diameter

Fig.14 Low CO emission ranges with different tortuosity

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Experiments on burning low calorific value H₂/CO in the porous media: effect of porous morphology and structure

多孔介质形貌与结构对低热值H₂/CO混合气燃烧特性影响的实验研究

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References 37

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