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过程工程学报 ›› 2022, Vol. 22 ›› Issue (11): 1565-1573.DOI: 10.12034/j.issn.1009-606X.221393

• 研究论文 • 上一篇    下一篇

回转窑二次风富氧燃烧的数值模拟

李全亮1， 梅书霞1， 谢峻林1*， 陈君2， 刘纲2， 杨新富2， 张海波2， 刘刚2   

  1. 1. 武汉理工大学材料科学与工程学院，湖北 武汉 430070 2. 鞍山冀东水泥有限责任公司，辽宁 鞍山 114042
  • 收稿日期:2021-11-29 修回日期:2022-01-20 出版日期:2022-11-28 发布日期:2022-11-28
  • 通讯作者: 谢峻林 xjlclxy@126.com
  • 作者简介:李全亮(1997-)，男，山东省德州市人，硕士研究生，主要从事燃烧及污染物减排的数值模拟研究工作，E-mail: 987437577@qq.com；通讯联系人，谢峻林，E-mail: xjlclx@126.com.

Numerical simulation of oxygen-enriched combustion in secondary air of rotary kiln

Quanliang LI1,  Shuxia MEI1,  Junlin XIE1*,  Jun CHEN2,  Gang LIU2,  Xinfu YANG2,#br#   Haibo ZHANG2,  Gang LIU2   

  1. 1. School of Material Science ＆ Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China 2. Anshan Jidong Cement Co., Ltd., Anshan, Liaoning 114042, China
  • Received:2021-11-29 Revised:2022-01-20 Online:2022-11-28 Published:2022-11-28

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摘要： 针对一实际尺寸的回转窑建立模型，分别进行了空气助燃(21% O2)和二次风富氧(23% O2)燃烧的数值模拟研究。结果表明，二次风富氧后，高温区覆盖形状没有明显变化，仍呈“棒槌状”；在回转窑前端，煤粉挥发分与焦炭燃烧速度加快，整体温度有所提升，最高温度由2386 K增至2427 K，壁面所接收的辐射量得到了提升；但NOx的生成量也大幅度提高，其中出口处NOx由247 mg/m3增至367 mg/m3。考虑到制氧成本问题及NOx排放问题，在二次风中进行富氧燃烧的总体效果不够理想。

关键词: 回转窑, 富氧燃烧, 煤粉燃烧, 二次风富氧, 数值模拟

Abstract: To explore the influence of secondary air oxygen enrichment on flame shape, temperature distribution, radiation, NOx concentration and other parameters of rotary kiln, the feasibility of secondary air oxygen enrichment was studied. The numerical simulation of oxygen enriched combustion in secondary air were carried out for a rotary kiln under actual working conditions by using ANSYS Fluent 15.0 software. For the gas phase, the RNG k-ε model was used to simulate the turbulent flow. For the particle phase (pulverized coal), the discrete phase model and discrete random walk model were used to calculate the trajectory of the particle phase. For the pulverized coal combustion process, the species transport model combined with the Finite-Rate/Eddy-Dissipation model was used, and radiation was expressed with the P-1 radiation model. The pollutant model was used to calculate the generation of NOx in the rotary kiln, considering the generation of thermal NOx and fuel NOx in the rotary kiln, and NOx reduction by reburning. The results showed that after the secondary air was enriched with oxygen, the gas flow fields near the burner did not change significantly, the covering shape of the high temperature area did not change obviously, and it was still in the shape of "mallet". At the front end of the rotary kiln, the combustion speed of pulverized coal volatile and char was accelerated, the overall temperature increased, the maximum temperature was increased from 2386 K to 2427 K, and the radiation received by the wall surafce was also increased. However, the generation of NOx had also increased significantly. According to the calculation, the mass concentration of NOx at the outlet increased from 247 mg/m3 to 367 mg/m3. Considering the cost of oxygen production and NOx emission, the overall effect of oxygen enriched combustion in secondary air was not ideal.

Key words: rotary kiln, oxygen-enriched combustion, pulverized coal combustion, oxygen-enriched combustion in secondary air, numerical simulation