Numerical study on oxy-fuel combustion of coal pre-gasification products in cement calciner
发布时间：2025-10-16
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- 发布时间：
- 2025-10-16
- 论文名称：
- Numerical study on oxy-fuel combustion of coal pre-gasification products in cement calciner
- 发表刊物：
- APPLIED THERMAL ENGINEERING
- 摘要：
- With the increasing concerns over global climate change, carbon emissions reduction in the cement industry has become a key focus. This paper investigates the temperature field, species distribution, and raw meal decomposition of pre-gasification oxy-fuel combustion in a 5500 t/d calciner. Numerical simulations are performed for various combustion conditions, including coal-fired, oxy-fuel, and pre-gasification combustion. An optimized pre-gasification staged combustion layout was designed for the cement calciner, and its emission reduction and production increase effects were validated through numerical simulations. It reveals that oxy-fuel combustion improves temperature uniformity and reduces local high-temperature zones. Compared to the air-fired case, the maximum temperature decreased by 71.42 K in the 21 % O2 concentration oxy-fuel combustion case. An increase in O2 concentration leads to higher temperatures and temperature non-uniformity. High CO2 concentrations in oxy-fuel combustion inhibit CaCO3 decomposition, while increasing O2 concentration significantly enhances the decomposition ratio. Both oxy-fuel and pre-gasification combustion significantly reduce NOx emissions. Under the oxy-coal combustion, compared to the air-fired case, NOx emissions were reduced by 56.12 % in the 21 % O2 concentration oxy-fuel combustion case. In unoptimized pre-gasification cases, the fuel burns out more quickly, resulting in an oxidizing atmosphere that slightly increases NOx at the outlet. Moreover, the residence time of CaCO3 in the lower calciner becomes shorter because the larger flow rate distributed in the reduction zone, causing a decrease in the CaCO3 decomposition ratio by 5.37 %. Therefore, the fuel inlets of pre-gasification combustion need to be arranged along the calciner to achieve multi-staged combustion to reduce the NOx emission. The optimized pre-gasification layout, along with oxy-fuel combustion, can achieve ultra-low NOx emissions (22.49 ppm) at the calciner outlet and significantly alleviate the issue of reduced raw meal decomposition rate caused by oxy-fuel combustion, reaching a CaCO3 decomposition ratio of 95.36 % under 30 % O2 concentration oxy-fuel combustion. In industrial applications, it is recommended to conduct oxy-fuel combustion in the cement calciner with this pre-gasification layout at 30 % O2 concentration to ensure that the decomposition ratio of cement raw meals remains above 95 %. This study provides a theoretical guide on how oxy-fuel and pre-gasification combustion technologies can be optimized to improve energy efficiency and reduce NOx emissions in cement production.
- 合写作者：
- Shu Yixiang, Yao Xin, Zhang Su, Zhang Hanlin, Li Xiangdong, Lin Hui, Zhang Jiaye, Wang Xiaoxiao, Tan Houzhang, Wang Xuebin
- 卷号：
- 275
- 是否译文：
- 否
- 发表时间：
- 2025-09-15
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