Study on decomposition characteristics of cement raw meal in suspension furnace at high altitude

doi:10.11949/0438-1157.20211802

Abstract

Abstract:

The atmospheric conditions of low pressure and low oxygen in high altitude areas affect the decomposition process of cement raw meal in the decomposition furnace, and it is of great significance to explore the decomposition characteristics of cement raw meal under these conditions. An experimental system was constructed to simulate a suspension furnace in high-altitude areas with low pressure, and was studied the reaction process of cement raw meal in the calciner. Also, the effects of pressure and temperature and O₂ concentration on the decomposition characteristics of cement raw meal were studied by changing the reaction conditions. The research results show that the decomposition of cement raw meal under low-pressure conditions conforms to the random nucleation and growth model. As the reaction pressure gradually decreases, the decomposition rate of cement raw meal gradually increases, and the specific surface area and pore volume of the reaction product gradually increase. But low-pressure conditions will aggravate the incomplete combustion of fuel and reduce the decomposition ratio of cement raw meal. The reaction rate of fuel and cement raw meal will gradually increase with the rise of reaction temperature, but the decomposition ratio of cement raw meal will increase firstly and then decrease. Under low-pressure conditions, the fuel reaction ratio and reaction rate increase with the increase of O₂ concentration, which can increase the decomposition rate of the reactant. Therefore, in high altitude areas, the decomposition rate and decomposition ratio of cement raw meal can be increased by appropriately increasing the reaction temperature or increasing the O₂ concentration of the reaction atmosphere.

Key words: cement raw meal, high altitude, fluidization, coal combustion, decomposition characteristics, reaction kinetics

摘要：

高海拔地区低压低氧的大气条件影响水泥生料在分解炉内的分解过程，探究水泥生料在该条件下的分解特性具有重要意义。通过构建模拟高海拔地区的低压悬浮炉实验系统，研究了压力、温度以及O₂浓度对高海拔条件下水泥生料分解特性的影响。研究结果表明：低压条件下水泥生料的分解符合随机成核和随后生长模型；随着反应压力的逐渐降低，水泥生料的分解速率逐渐增大，反应产物的比表面积以及比孔体积逐渐增大；但低压条件会加剧燃料的不完全燃烧，降低水泥生料的分解率；燃料以及水泥生料的反应速率均会随着反应温度的上升而逐渐增大，但水泥生料的分解率会先升高再降低；燃料的燃尽率以及反应速率随着O₂浓度的增加而增大，进而提高反应物的反应速率。

关键词: 水泥生料, 高海拔, 流态化, 煤燃烧, 分解特性, 反应动力学

CLC Number:

TQ 172

Cong HE, Wenqi ZHONG, Guanwen ZHOU, Xi CHEN. Study on decomposition characteristics of cement raw meal in suspension furnace at high altitude[J]. CIESC Journal, 2022, 73(5): 2120-2129.

何聪, 钟文琪, 周冠文, 陈曦. 高海拔地区水泥生料悬浮炉分解特性研究[J]. 化工学报, 2022, 73(5): 2120-2129.

Figures/Tables 16

Fig.1 Schematic view of low-pressure suspension furnace

Table 1 Chemical composition analysis of cement raw meal

烧失量/%(质量)	CaO/% (质量)	SiO₂/% (质量)	Al₂O₃/% (质量)	Fe₂O₃/% (质量)	MgO/% (质量)	K₂O/% (质量)	Na₂O/% (质量)	TiO₂/% (质量)	ZnO/% (质量)	SO₃/% (质量)
35.40	46.05	9.59	3.21	2.53	1.74	0.64	0.24	0.16	0.12	0.10

Table 2 Proximate analysis， ultimate analysis and calorific value of coal sample

工业分析/%(质量)				元素分析/%(质量)					Q_gr,ad/ (kJ/kg)
M_ad	V_ad	A_ad	FC_ad	C_ad	H_ad	O_ad	N_ad	S_ad	Q_gr,ad/ (kJ/kg)
10.24	26.93	17.55	45.28	62.54	3.84	3.56	1.53	0.74	25492.32

Table 3 Experimental conditions

工况	反应物料	反应压力p/MPa	海拔高度h/m	温度T/℃	c_O2/%	物料量(煤)m_c/g	物料量(生料)m_r/g
1	煤	0.06	4200	850	21	0.03	0
2		0.08	2000	850	21	0.03	0
3		0.10	0	850	21	0.03	0
4	生料	0.06	4200	850	21	0	0.50
5		0.08	2000	850	21	0	0.50
6		0.10	0	850	21	0	0.50
7	混合物	0.06	4200	850	21	0.03	0.50
8		0.08	2000	850	21	0.03	0.50
9		0.10	0	850	21	0.03	0.50
10	煤	0.08	2000	800	21	0.03	0
11		0.08	2000	850	21	0.03	0
12		0.08	2000	900	21	0.03	0
13	生料	0.08	2000	800	21	0	0.50
14		0.08	2000	850	21	0	0.50
15		0.08	2000	900	21	0	0.50
16	混合物	0.08	2000	800	21	0.03	0.50
17		0.08	2000	850	21	0.03	0.50
18		0.08	2000	900	21	0.03	0.50
19	煤	0.08	2000	850	21	0.03	0
20		0.08	2000	850	30	0.03	0
21		0.08	2000	850	40	0.03	0
22	混合物	0.08	2000	850	21	0.03	0.50
23		0.08	2000	850	30	0.03	0.50
24		0.08	2000	850	40	0.03	0.50

Fig.2 The influence of pressure on the concentration of CO2 generated by the reaction of coal

Fig.3 The influence of pressure on the concentration of CO2 generated by the reaction of raw meal

Fig.4 The influence of pressure on the concentration of CO2 generated by the reaction of mixture

Fig.5 The total volume and average rate of CO2 generated by the reaction with different pressures

Fig.6 The specific surface area and specific pore volume of the reaction product with different pressures

Fig.7 The influence of temperature on the concentration of CO2 generated by the reaction of coal

Fig.8 The influence of temperature on the concentration of CO2 generated by the reaction of raw meal

Fig.9 The influence of temperature on the concentration of CO2 generated by the reaction of mixture

Fig.10 The total volume and average rate of CO2 generated by the reaction with different temperatures

Fig.11 The influence of O2 concentration on the concentration of CO2 generated by the reaction of coal

Fig.12 The influence of O2 concentration on the concentration of CO2 generated by the reaction of mixture

Fig.13 The total volume and average rate of CO2 generated by the reaction with different O2 concentration

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