刘鹏宇,李德波,刘彦丰,廖宏楷,冯永新
LIU Pengyu,LI Debo,LIU Yanfeng,LIAO Hongkai,FENG Yongxin

• 1:华北电力大学动力工程系
• 2:南方电网电力科技股份有限公司

摘要(Abstract)：

焦炭燃烧是燃煤电厂锅炉中煤粉燃烧的主要过程，其燃烧过程由动力燃烧区、扩散/动力区和扩散控制区组成，其中以扩散/动力区的燃烧过程及机理最复杂，影响焦炭燃烧的数值模拟精度。为进一步提高燃煤电厂锅炉侧数值模拟精度，对FLUENT自带模型、改进的随机孔模型及已有的焦炭燃烧改进模型进行了综述与横向对比。结果表明：FLUENT自带模型未考虑实际燃烧时灰分对氧气扩散的影响，造成数值模拟与工程实际差别较大；基于改进的随机孔模型，认为温度是导致扩散区中氧气难以与焦炭接触的原因，但并非根本因素；现有模型普遍未考虑工程实际中燃用劣质煤种时内表面积对反应速率的影响，造成低转化率阶段预测值与实际值偏差较大；考虑灰层扩散阻力缩核模型的应用时，应先比较燃用煤种的软化温度与燃烧温度，且考虑热失活和多孔碳球内表面积；热失活和灰分抑制模型应采用更适宜的灰分抑制模型，提高模型预测精度；目前基于FLUENT对燃煤锅炉其他问题进行数值模拟时，均采用误差很大的扩散/动力模型，后续研究中采用改进后的焦炭燃烧模型是重要研究方向。
Coke combustion is the main process of pulverized coal combustion in coal-fired power plant boilers, and its combustion process consists of power combustion zone, diffusion/dynamic zone and diffusion control zone, among which the combustion process and mechanism in the diffusion/dynamic zone are the most complicated and often affect the accuracy of numerical simulation of coke combustion. To further improve the accuracy of the numerical simulation on the boiler side of coal-fired power plants, the FLUENT self-contained model, the improved random hole model and the existing improved model for coke combustion were reviewed and compared. The results show that the self-contained model of FLUENT does not consider the influence of ash on oxygen diffusion during actual combustion, resulting in large differences between numerical simulation and engineering practice.Based on the improved random pore model, it is considered that temperature is the reason for the difficulty of oxygen contact with coke in the diffusion zone, but it is not the fundamental factor.The existing models generally do not consider the influence of internal surface area on the reaction rate when burning poor quality coal in engineering practice, resulting in large differences between predicted and actual values at the stage of low conversion rate.In the application of nucleation model considering the diffusion resistance of ash layer, the softening temperature of combustion coal with the combustion temperature should be compared first, and the consideration of thermal deactivation and the internal surface area of porous carbon spheres should be considered.The thermal deactivation and ash suppression model should adopt a more suitable ash suppression model to improve the accuracy of model prediction.At present, in the numerical simulation of other problems of coal-fired boiler based on FLUENT, the diffusion/dynamic models with large errors are used, and the adoption of improved coke combustion models in subsequent studies is an important research direction.

关键词(KeyWords)： 燃煤电厂;煤粉燃烧;焦炭燃烧模型;随机孔模型;反应速率;数值模拟
coal fired power plants;pulverized coal combustion;coke combustion model;random hole model;reaction rate;numerical simulation

Abstract:

Keywords:

基金项目(Foundation): 国家自然科学基金资助项目(51376161)

作者(Author): 刘鹏宇,李德波,刘彦丰,廖宏楷,冯永新
LIU Pengyu,LI Debo,LIU Yanfeng,LIAO Hongkai,FENG Yongxin

DOI: 10.13226/j.issn.1006-6772.21080406

参考文献(References)：

• [1] 崔星源.超临界煤粉锅炉低NOx燃烧数值模拟[D].北京：华北电力大学，2006.
• [2] 张志，李振山，蔡宁生.煤粉燃烧中焦炭燃烧模型的比较与分析[J].燃烧科学与技术，2014,20(5):393-400.ZHANG Zhi,LI Zhenshan,CAI Ningsheng.Comparison and analysis of coke combustion models in pulverized coal combustion[J].Combustion Science and Technology,2014,20(5):393-400.
• [3] 贾永会，闫慧博，杜建桥，等.基于灰层累积的焦炭燃烧缩核模型FLUENT数值模拟研究[J].热科学与技术，2020,19(5):495-502.JIA Yonghui,YAN Huibo,DU Jianqiao,et al.Numerical simulation research on FLUENT model of coke combustion based on accumulation of ash layer[J].Thermal Science and Technology,2020,19(5):495-502.
• [4] 丁历威，李凤瑞.Fluent软件模拟计算煤粉燃烧的机理及其模型实现的方式[J].浙江电力，2010,29(11):31-34.DING Liwei,LI Fengrui.Mechanism and model realization of pulverized coal combustion simulation and calculation with FLUENT[J].Zhejiang Electric Power,2010,29(11):31-34.
• [5] BADZIOCH S,HAWKSLEY P G W,PETER C W.Kinetics of thermal decomposition of pulverized coal particles[J].Industrial & Engineering Chemistry Process Design and Development,1970,9(4):521-530.
• [6] WILLIAMS A,BACKREEDY R,HABIB R,et al.Modelling coal co-mbustion:The current position[J].Fuel,2002,81(5):605-618.
• [7] BHATIA S K,PERLMUTTER D D.A random pore model for fluid-solid reactions[J].Chemical Engineering Science,2016,61(11):3725-3735.
• [8] 陈明磊，李保卫，武文斐.焦炭颗粒在不同控制区域中的燃烧特性[J].过程工程学报，2014,14(2):291-295.CHEN Minglei,LI Baowei,WU Wenfei.Combustion characteristics of char particles in different controlling regions[J].The Chinese Journal of Process Engineering,2014,14(2):291-295.
• [9] 曲践，李保卫，龚志军，等.O2/CO2气氛下单颗粒焦炭燃烧竞争效应的数值模拟[J].过程工程学报，2017,17(4):725-731.QU Jian,LI Baowei,GONG Zhijun,et al.Numerical simulation of the competition effects of single particle coke combustion in O2/CO2 atmosphere[J].CIESC Journal,,2017,17(4):725-731.
• [10] 曲践，李保卫，郑坤灿，等.O2/CO2气氛下多种碳基随机孔模型的建立[J].化工学报，2016,67(10):4468-4476.QU Jian,LI Baowei,ZHENG Kuncan,et al.Establishment of various char-RPM under O2/CO2 atmosphere[J].CIESC Journal,2016,67(10):4468-4476.
• [11] 李德波，狄万丰，李鑫，等.1 045 MW超超临界贫煤锅炉燃用高挥发分烟煤的燃烧调整研究及工程实践[J].热能动力工程，2016,31(1):117-123,139-140.LI Debo,DI Wanfeng,LI Xin,et al.Combustion adjustment research and engineering practice of 1 045 MW ultra-supercritical lean coal boiler burning high volatile bituminous coal[J].Thermal Energy and Power Engineering,2016,31(1):117-123,139-140.
• [12] 徐启，邢嘉芯，张梦竹，等.低NOx旋流燃烧器燃烧特性数值模拟[J].科学技术与工程，2020(20):8168-8174.XU Qi,XING Jiaxin,ZHANG Mengzhu,et al.Numerical simulation of combustion characteristics of low NOx swirl burner[J].Science Technology and Engineering,2020(20):8168-8174.
• [13] 刘鹏宇，李德波，刘彦丰，等.燃煤电厂锅炉机组受热面积灰结渣研究现状与展望[J].洁净煤技术，2022,28(5):87-96.LIU Pengyu,LI Debo,LIU Yanfeng,et al.Current status and prospects of research on ash slagging in heated area of coal-fired power plant boiler unit[J].Clean Coal Technology,2022,28(5):87-96.
• [14] 张志，李振山，蔡宁生.焦炭燃烧模型的改进及其Fluent实现与实验验证[J].中国电机工程学报，2015,35(7):1681-1688.ZHANG Zhi,LI Zhenshan,CAI Ningsheng.Improvement of coke combustion model and its Fluent realization and experimental verification[J].Proceedings of the Chinese Society for Electrical Engineering,2015,35(7):1681-1688.
• [15] LIU Hao.Combustion of coal chars inO2/CO2 and O2/N2 mixtures:A comparative study with non-isothermal thermogravimetric analyzer(TGA) tests[J].Energy & Fuels,2009,23(9):4278-4285.
• [16] 陈世和，朱亚清，罗嘉，等.FLUENT中煤粉燃烧飞灰含碳量数值模型的改进[J].热能动力工程，2014,29(3):315-319,346-347.CHEN Shihe,ZHU Yaqing,LUO Jia,et al.Improvement of the numerical model of carbon content in fly ash from pulverized coal combustion in FLUENT[J].Thermal Energy and Power Engineering,2014,29(3):315-319,346-347.
• [17] 李新号.基于灰分抑制作用FLUENT焦炭燃烧模型改进及新型网格处理方法[D].保定：华北电力大学，2017.
• [18] 陈世和，罗嘉，张曦，等.若干因素对电站锅炉飞灰含碳量影响的数值研究[J].锅炉技术，2015,46(1):40-44.CHEN Shihe,LUO Jia,ZHANG Xi,et al.Numerical study on the influence of several factors on the carbon content of fly ash from power station boilers[J].Boiler Technology,2015,46(1):40-44.
• [19] 王淦，温治，楼国锋，等.基于热分析动力学的烧结用焦炭颗粒燃烧数值模拟[J].中南大学学报(自然科学版),2016,47(10):3315-3322.WANG Gan,WEN Zhi,LOU Jianguo,et al.Numerical simulation on combustion characteristics of sintering used coal char particle based on thermo-gravimetric kinetic analysis[J].Journal of Central South University(Science and Technology),2016,47(10):3315-3322.
• [20] 冯万国，楼国锋，王淦.不同气氛下焦炭燃烧动力学实验研究[J].化工进展，2017,36(2):487-493.FENG Wanguo,LOU Guofeng,WANG Gan.Experient investigation on combustion characteristics and kinetics of coke under different atmosphere[J].Chemical Industry and Engineering Progress,2017,36(2):487-493.
• [21] 冯俊凯，沈幼庭，杨瑞昌.锅炉原理与计算[M].北京：科学出版社，2003.
• [22] KARLSTR?M O,BRINK A,HERCOG J,et al.One-parameter model for the oxidation of pulverized bituminous coal Chars[J].Energy & Fuels,2012,26(2):968-975.
• [23] 王潜龙，汪小憨，曾小军，等.多孔焦炭燃烧特性的模型构建及数值模拟[J].工程热物理学报，2012,33(1):167-170.WANG Qianlong,WANG Xiaohan,ZENG Xiaojun,et al.Model construction and numerical simulation of porous coke combustion characteristics[J].Journal of Engineering Thermophysics,2012,33(1):167-170.
• [24] FU W B,ZHANG B L,ZHENG S M.A relationship between the kinetic parameters of char combustion and the coal′s properties[J].Combustion and Flame,1997,109(4):587-598.
• [25] LU G Q,DO D D.A kinetic study of coal reject-derived char activation with CO2,H2O,and air[J].Pergamon,1992,30(1):21-29.
• [26] HURT Robert,SUN Jiankuan,MELISSA Lunden.A kinetic model of carbon burnout in pulverized coal combustion[J].Combustion and Flame,1998,113(1/2):181-197.
• [27] 王苑，罗永浩，季俊杰，等.大颗粒煤反应过程中灰层有效扩散系数的研究[J].煤炭转化，2010,33(3):87-91.WANG Yuan,LUO Yonghao,JI Junjie,et al.Study on the effective diffusion coefficient of ash layer during the reaction of large coal particles[J].Coal Conversion,2010,33(3):87-91.
• [28] 刘森.600 MW前后墙旋流对冲锅炉燃烧优化数值模拟[D].武汉：华中科技大学，2019.
• [29] 杜智华，蒙毅，孙军.530 MW超临界机组对冲燃烧锅炉低氮燃烧贴壁风系统数值计算[J].动力工程学报，2017,37(6):425-431.DU Zhihua,MENG Yi,SUN Jun.Numerical calculation of low-nitrogen combustion close-to-wall air system of a 530 MW supercritical unit opposed combustion boiler[J].Chinese Journal of Power Engineering,2017,37(6):425-431.
• [30] 李永生，刘建民，陈国庆，等.对冲旋流燃烧锅炉侧墙水冷壁近壁区还原性气氛分布特性[J].动力工程学报，2017,37(7):513-519,539.LI Yongsheng,LIU Jianmin,CHEN Guoqing,et al.Distribution characteristics of reducing atmosphere near the water wall of the side wall of the opposed swirling combustion boiler[J].Chinese Journal of Power Engineering,2017,37(7):513-519,539.
• [31] 徐国群，陈国庆.对冲旋流燃烧锅炉炉膛壁面氛围数值模拟分析[J].电力科技与环保，2017,33(6):44-48.XU Guoqun,CHEN Guoqing.Numerical simulation analysis of the furnace wall atmosphere of the hedging swirl combustion boiler[J].Electric Power Technology and Environmental Protection,2017,33(6):44-48.
• [32] 朱宣而，黄亚继，岳峻峰，等.旋流对冲锅炉侧墙贴壁风结构优化及布置数值模拟[J].洁净煤技术，2021,27(3):174-181.ZHU Xuan′er,HUANG Yaji,YUE Junfeng,et al.Numerical simulation of structural optimization and layout of air flow against side wall of swirling opposed boiler[J].Clean Coal Technology,2021,27(3):174-181.
• [33] 孟凡冉，高畅，金保昇，等.异距贴壁风喷口布置方案的数值模拟[J].化工进展，2017,36(9):3237-3242.MENG Fanran,GAO Chang,JIN Baosheng,et al.Numerical simulation of the layout scheme of different distance adhering air nozzles[J].Progress in Chemical Industry,2017,36(9):3237-3242.
• [34] 李新号，王春波，郭永成，等.旋流对冲燃烧器出口条件给定方式优化[J].热力发电，2017,46(5):91-97.LI Xinhao,WANG Chunbo,GUO Yongcheng,et al.Optimization of the setting method of the outlet conditions of the swirling flow hedge burner[J].Thermal Power Generation,2017,46(5):91-97.
• [35] 李德波，徐齐胜，沈跃良，等.660 MW超临界锅炉DBC-OPCC型旋流燃烧器大面积烧损关键原因分析及其改造措施研究[C]//第十八届全国二氧化硫氮氧化物汞污染防治暨细颗粒物(PM2.5)治理技术研讨会.北京：中国环境科学学会，2014:13.
• [36] 袁来运.超临界煤粉锅炉变负荷燃烧的数值模拟及配风优化[D].南京：东南大学，2019.