SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2014, Vol. 22 ›› Issue (2): 193-201.DOI: 10.1016/S1004-9541(14)60032-X

• 能源、资源与环境技术 • 上一篇    下一篇

Numerical Simulation of Oxy-coal Combustion for a Swirl Burner with EDC Model

崔凯, 刘冰, 吴玉新, 杨海瑞, 吕俊复, 张海   

  1. Key Laboratory for Thermal Science and Power Engineering of Ministry Education, Department of Thermal Engi-neering, Tsinghua University, Beijing 100084, China
  • 收稿日期:2012-03-26 修回日期:2013-03-04 出版日期:2014-02-05 发布日期:2014-01-28
  • 通讯作者: ZHANG Hai
  • 基金资助:

    Supported by the Chinese Ministry of Science and Technology Project (2011DFA60390) and The National High Technology Research and Development Program of China (2007AA05Z303).

Numerical Simulation of Oxy-coal Combustion for a Swirl Burner with EDC Model

CUI Kai, LIU Bing, WU Yuxin, YANG Hairui, LÜ Junfu, ZHANG Hai   

  1. Key Laboratory for Thermal Science and Power Engineering of Ministry Education, Department of Thermal Engi-neering, Tsinghua University, Beijing 100084, China
  • Received:2012-03-26 Revised:2013-03-04 Online:2014-02-05 Published:2014-01-28
  • Contact: ZHANG Hai
  • Supported by:

    Supported by the Chinese Ministry of Science and Technology Project (2011DFA60390) and The National High Technology Research and Development Program of China (2007AA05Z303).

摘要: The characteristics of oxy-coal combustion for a swirl burner with a specially designed preheating chamber are studied numerically. In order to increase the accuracy in the prediction of flame temperature and ignition position, eddy dissipation concept (EDC) model with a skeletal chemical reaction mechanism was adopted to describe the combustion of volatile matter. Simulation was conducted under six oxidant stream conditions with different O2/N2/CO2 molar ratios: 21/79/0, 30/70/0, 50/50/0, 21/0/79, 30/0/70 and 50/0/50. Results showed that O2 enrichment in the primary oxidant stream is in favor of combustion stabilization, acceleration of ignition and increase of maximum flame temperature, while the full substitution of N2 by CO2 in the oxidant stream delays ignition and decreases the maximum flame temperature. However, the overall flow field and flame shapes in these cases are very similar at the same flow rate of the primary oxidant stream. Combustion characteristics of the air-coal is similar to that of the oxy-coal with 30% O2 and 70% CO2 in the oxidant stream, indicating that the rear condition is suitable for retrofitting an air-coal fired boiler to an oxy-coal one. The swirl burner with a specially designed preheating chamber can increase flame temperature, accelerate ignition and enhance burning intensity of pulverized coal under oxy-coal combustion. Also, qualitative experimental validation indicated the burner can reduce the overall NOx emission under certain O2 enrichment and oxy-coal combustion conditions against the air-coal combustion.

关键词: oxy-coal, eddy dissipation concept model, coal, swirl burner

Abstract: The characteristics of oxy-coal combustion for a swirl burner with a specially designed preheating chamber are studied numerically. In order to increase the accuracy in the prediction of flame temperature and ignition position, eddy dissipation concept (EDC) model with a skeletal chemical reaction mechanism was adopted to describe the combustion of volatile matter. Simulation was conducted under six oxidant stream conditions with different O2/N2/CO2 molar ratios: 21/79/0, 30/70/0, 50/50/0, 21/0/79, 30/0/70 and 50/0/50. Results showed that O2 enrichment in the primary oxidant stream is in favor of combustion stabilization, acceleration of ignition and increase of maximum flame temperature, while the full substitution of N2 by CO2 in the oxidant stream delays ignition and decreases the maximum flame temperature. However, the overall flow field and flame shapes in these cases are very similar at the same flow rate of the primary oxidant stream. Combustion characteristics of the air-coal is similar to that of the oxy-coal with 30% O2 and 70% CO2 in the oxidant stream, indicating that the rear condition is suitable for retrofitting an air-coal fired boiler to an oxy-coal one. The swirl burner with a specially designed preheating chamber can increase flame temperature, accelerate ignition and enhance burning intensity of pulverized coal under oxy-coal combustion. Also, qualitative experimental validation indicated the burner can reduce the overall NOx emission under certain O2 enrichment and oxy-coal combustion conditions against the air-coal combustion.

Key words: oxy-coal, eddy dissipation concept model, coal, swirl burner