Effect of burner bias angle on distribution characteristics of gasifier slag layer

doi:10.11949/0438-1157.20230140

Abstract

Abstract:

The ash-slag ratio (the fly ash carried away by syngas to slag deposited on the wall) of the gasifier is critical to the service life of subsequent syngas cleaning equipment. Optimizing the bias angle of burners is an effective way to control the ash-slag ratio of gasifier. The effects of the bias angle of four burners in the first stage of HNCERI (Huaneng Clean Energy Research Institute) gasifier on the ash-slag ratio, slag layer and refractory material are studied by numerical simulation method. The numerical simulation results show that when the bias angle of burners increases from 0°to 4.5°, the ash-slag ratio decreases from 2.0 to 0.8, and the average residence time of liquid slag layer reduced by 31.5%. With the increase of bias angle, the thickness of liquid/solid slag layer increases at the slag tap hole. While the thickness of solid slag layer decreases and the thickness of liquid slag layer increases at H=4.45—5.07 m. The velocity of liquid slag is negatively correlated with the viscosity of the liquid slag and positively correlated with the thickness of the liquid slag. The liquid slag thickness is mainly affected by the velocity of the liquid slag and the particle deposition rate. With the increase of the bias angle, the average temperature of the refractory material surface above the burner plane increases and below the burner plane decreases. When the bias angle is 3.5°, the highest temperature of the refractory material is the lowest. On the premise of effectively reducing the ash-slag ratio, reducing the possibility of the slag block, slag layer falling off and refractory material ablation, the HNCERI gasifier burner deflection angle is recommended to be 3.5°.

Key words: gasification, viscosity, complex fluids, optimal design, ash-slag ratio, slag flow characteristics

摘要：

气化炉灰渣比(合成气携带走的飞灰与沉积至壁面的熔渣的质量比)是影响后续合成气净化设备寿命的关键因素，优化烧嘴偏转角度是控制气化炉灰渣比的有效方法。采用数值模拟方法，研究了HNCERI (Huaneng Clean Energy Research Institute)气化炉一段四烧嘴偏转角度对气化炉灰渣比、壁面渣层及耐火材料的影响。数值模拟结果表明，烧嘴偏转角度由0°增加至4.5°，灰渣比由2.0降低至0.8，液态渣层平均停留时间减少31.5%。偏转角度增加，渣口位置液/固态渣层厚度均增加；H=4.45~5.07 m位置固态渣层厚度下降，液态渣层厚度则增加。液态渣层流速与黏度呈负相关，与厚度呈正相关，液态渣层厚度主要受流速和颗粒沉积率影响。偏转角度增加，烧嘴平面上方耐火材料表面平均温度升高，烧嘴平面下方耐火材料表面平均温度降低，偏转角度为3.5°时耐火材料需要承受的最高温度取得最低值。在有效降低灰渣比前提下，为减少气化炉堵渣、渣层脱落和耐火材料烧蚀概率，HNCERI气化炉烧嘴偏转角度建议取3.5°。

关键词: 气化, 黏度, 复杂流体, 优化设计, 灰渣比, 渣层流动特性

CLC Number:

TK 227

Bimao ZHOU, Shisen XU, Xiaoxiao WANG, Gang LIU, Xiaoyu LI, Yongqiang REN, Houzhang TAN. Effect of burner bias angle on distribution characteristics of gasifier slag layer[J]. CIESC Journal, 2023, 74(5): 1939-1949.

周必茂, 许世森, 王肖肖, 刘刚, 李小宇, 任永强, 谭厚章. 烧嘴偏转角度对气化炉渣层分布特性的影响[J]. 化工学报, 2023, 74(5): 1939-1949.

Figures/Tables 17

Fig.1 Schematic diagram of gasifier and wall slag layer

Table 1 Kinetic parameters of gas phase chemical reaction［21］

序号	均相反应	指前因子A_i /(kg/（m²·s·Pa））	活化能E_i /(J/kmol)
1	Vol $→$ C₇H₈+ CO + H₂+ N₂+ 0.0179 H₂S	4.26×10⁵	1.08×10⁸
2	Vol + 1.21355 O₂ $→$ CO + H₂O + N₂+ H₂S	9.2×10⁶	8.02×10⁷
3	H₂+ 0.5 O₂ $→$ H₂O	6.8×10¹⁵(β=-1)	1.68×10⁸
4	CO + H₂O $→$ CO₂ + H₂	2.75×10¹⁰	8.37×10⁷
5	CO + 0.5 O₂ $→$ CO₂	2.239×10¹²	1.674×10⁸
6	CO₂ + H₂ $→$ CO + H₂O	2.2×10⁷	1.98×10⁸
7	C₆H₆ + 3 O₂ $→$ 6 CO + 3 H₂	1.58×10¹⁵	2.206×10⁸
8	CH₄ + 0.5 O₂ $→$ 2 H₂ + CO	4.4×10¹¹	1.25×10⁸
9	C₆H₆ + 6 H₂O $→$ 6 CO + 9 H₂	3.0×10⁸	1.26×10⁸
10	C₇H₈ + 9 O₂ $→$ 7 CO₂+ 4 H₂O	1.6×10⁸	1.255×10⁸
11	C₆H₆ + 7.5 O₂ $→$ 6 CO₂ + 3 H₂O	1.125×10⁹	1.256×10⁸
12	C₇H₈+ H₂ $→$ C₆H₆+ CH₄	1.04×10¹²	2.47×10⁸
13	CH₄ + H₂O $→$ CO + 3H₂	3×10⁸	1.25×10⁸

Table 1 Kinetic parameters of gas phase chemical reaction［21］

序号	均相反应	指前因子A_i /(kg/（m²·s·Pa））	活化能E_i /(J/kmol)
1	Vol $→$ C₇H₈+ CO + H₂+ N₂+ 0.0179 H₂S	4.26×10⁵	1.08×10⁸
2	Vol + 1.21355 O₂ $→$ CO + H₂O + N₂+ H₂S	9.2×10⁶	8.02×10⁷
3	H₂+ 0.5 O₂ $→$ H₂O	6.8×10¹⁵(β=-1)	1.68×10⁸
4	CO + H₂O $→$ CO₂ + H₂	2.75×10¹⁰	8.37×10⁷
5	CO + 0.5 O₂ $→$ CO₂	2.239×10¹²	1.674×10⁸
6	CO₂ + H₂ $→$ CO + H₂O	2.2×10⁷	1.98×10⁸
7	C₆H₆ + 3 O₂ $→$ 6 CO + 3 H₂	1.58×10¹⁵	2.206×10⁸
8	CH₄ + 0.5 O₂ $→$ 2 H₂ + CO	4.4×10¹¹	1.25×10⁸
9	C₆H₆ + 6 H₂O $→$ 6 CO + 9 H₂	3.0×10⁸	1.26×10⁸
10	C₇H₈ + 9 O₂ $→$ 7 CO₂+ 4 H₂O	1.6×10⁸	1.255×10⁸
11	C₆H₆ + 7.5 O₂ $→$ 6 CO₂ + 3 H₂O	1.125×10⁹	1.256×10⁸
12	C₇H₈+ H₂ $→$ C₆H₆+ CH₄	1.04×10¹²	2.47×10⁸
13	CH₄ + H₂O $→$ CO + 3H₂	3×10⁸	1.25×10⁸

Table 2 Kinetic parameters of heterogeneous reaction of char［23］

序号	异相反应	n_i	ψ_i	A_i	E_p_,i /(J/kmol)
1	C+H₂O $→$ CO+H₂	0.64	3	4.18×10⁴ Pa^-0.64·s^-1	2.52×10⁸
2	C+CO₂ $→$ 2CO	0.54	3	6.27×10⁵ Pa^-0.54·s^-1	2.83×10⁸
3	C+0.5 O₂ $→$ CO	0.68	14	1.13×10² Pa^-0.68·s^-1	1.30×10⁸

Table 2 Kinetic parameters of heterogeneous reaction of char［23］

序号	异相反应	n_i	ψ_i	A_i	E_p_,i /(J/kmol)
1	C+H₂O $→$ CO+H₂	0.64	3	4.18×10⁴ Pa^-0.64·s^-1	2.52×10⁸
2	C+CO₂ $→$ 2CO	0.54	3	6.27×10⁵ Pa^-0.54·s^-1	2.83×10⁸
3	C+0.5 O₂ $→$ CO	0.68	14	1.13×10² Pa^-0.68·s^-1	1.30×10⁸

Fig.2 Schematic diagram of iterative calculation of model

Table 3 Inlet boundary conditions

项目	质量流率/(kg/h)
项目	O₂	H₂O	coal
一段	63198.83	2000	69626.8
二段	0	0	2603.62

Fig.3 Viscosity-temperature characteristic curve of slag

Table 4 Properties of the coal

工业分析/%(mass, ar)				元素分析/%(mass, d)					Q_net/(MJ/kg)
M	A	V	FC	C	H	N	S	O	Q_net/(MJ/kg)
3.88	11.09	32.15	52.88	69.78	4.27	1.25	0.25	9.22	28.3

Table 5 Comparison of model verification data

项目	CO/%	H₂/%	CO₂/%	一段散热量/MW	一段碳转化率/%
工业数据	57.52	23.93	3.32	9~10.3	99.42
模拟数据	57.11	23.90	3.97	9.31	99.54

Fig.4 Distribution of layer velocity and viscosity of liquid slag at different heights under basic working conditions

Fig.5 Distribution of velocity and viscosity of liquid slag layer under basic working conditions

Fig.6 Residence time distribution of slag layer under basic working conditions

Fig.7 Effect of bias angle on surface temperature, deposition rate and ash-slag ratio of liquid slag layer

Fig.8 Effect of bias angle on slag layer thickness, temperature distribution and heat flux density

Fig.9 Viscosity, velocity and average value of liquid slag layer at slag tap hole

Fig.10 Effect of bias angle on slag layer thickness, temperature distribution and flow characteristics at 4.45—5.07 m

Fig.11 Surface temperature distribution of refractories

Fig.12 Average residence time of liquid slag layer with different bias angles

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