0.5 MW富氧燃烧煤粉炉循环倍率对辐射传热的影响
|
摘要
本文以某0.5 MW富氧燃烧煤粉炉为研究对象,采用改进的气体、颗粒辐射特性模型以及富氧燃烧骨架机理,对煤粉空气燃烧以及不同烟气循环倍率下的富氧燃烧进行了数值模拟,对炉内气流分布、温度分布以及壁面热流进行了详细地分析。研究结果表明,不同燃烧条件下,预测的壁面辐射热流与试验测量值具有很好的一致性;烟气循环倍率对炉内温度以及传热具有很好的调节作用,在本文中,当循环倍率为67%时,富氧燃烧的炉内峰值温度与空气燃烧基本一致,但传热能力增强;当循环倍率为71%时,富氧燃烧的传热量与空气燃烧一致。
In this study, improved gas and particle radiative property models and a skeletal mechanism are used to simulate the pulverized coal combustion, including the air-nombustion and oxy-fuel combustion with different flue gas recycle ratios. Calculations are presented for experiments carried out in the RWEn 0.5 MWth combustion test facility. In-furnace flow patterns, flue gas temperature distribution, and radiative heat transfer are analyzed in detail. The results show that the predicted radiative heat fluxes on the wall are in good agreement with measurements in all cases. The in-furnace temperature and radiative heat transfer are significantly impacted by flue gas recycle ratios. In this study, at flue gas recycle ratio of 67%, the peak temperature in oxy-fuel combustion is similar with that in air-nombustion, but the heat transfer capability is enhanced. When the recycle ratio is 71%,the radiative heat transfer in oxy-fuel combustion can match with that in air-combustion.
In this study, improved gas and particle radiative property models and a skeletal mechanism are used to simulate the pulverized coal combustion, including the air-nombustion and oxy-fuel combustion with different flue gas recycle ratios. Calculations are presented for experiments carried out in the RWEn 0.5 MWth combustion test facility. In-furnace flow patterns, flue gas temperature distribution, and radiative heat transfer are analyzed in detail. The results show that the predicted radiative heat fluxes on the wall are in good agreement with measurements in all cases. The in-furnace temperature and radiative heat transfer are significantly impacted by flue gas recycle ratios. In this study, at flue gas recycle ratio of 67%, the peak temperature in oxy-fuel combustion is similar with that in air-nombustion, but the heat transfer capability is enhanced. When the recycle ratio is 71%,the radiative heat transfer in oxy-fuel combustion can match with that in air-combustion.
引文
[1] Andersson K, Johansson R, Hjartstan S, et al. Radiation Intensity of Lignite-fired Oxy-fiel Flames[J]. Experimental Thermal and Fluid Science, 2008, 33(1):67-76
[2] Tan Y, Croiset E, Dougla, M A, et al. Combustion Characteristics of Coal in a Mixture of Oxygei and Recycled Flue Gas[J]. Fuel, 2006, 85(4):507-512
[3] Smart J P, O'nions P, Riley G S. Radiation and Convective Heat Transfer, and Burnout in Oxy-coal Combustion[J]. Fuel, 2010, 89(9):2468-2476
[4] GUO Junjun, LIU Zhaohui, HUANG Xiaorong, et al.Experimental and Numerical Investigations on Oxy-coal Combustion in a 35 MW Large Pilot Boiler[J]. Fuel, 2017,187:315-327
[5] GUO Junjun. LIU Zhaohui, WANG Peng, et al. Numerical Investigation on Oxy-combustion Characteristics of a200 MW_e Tangentially Fired Boiler[J]. Fuel, 2015, 140:660-668
[6]李鹏飞,徐敏义,王飞飞.精通CFD工程仿真与案例实战[M].北京:人民邮电出版社,2011LI Pengfei, XU Minyi, WANG Feifei. Proficiency in CFD Engineering Simulation and Cases[M]. Beijing:Posts&Telecom Press, 2011
[7] Fletcher T, Kerstein A, Pugmire R, et al. Chemical Percolation Model for Devolatilization. 3. Direct Use of Carbon-13 NMR Data to Predict Effects of Coal Type[J]. Energy Fuels, 1992, 6:414-431
[8] Petersen I, Werther J. Experimental Investigation and Modeling of Gasification of Sewage Sludge in the Circulating Fluidized Bed[J]. Chemical Engineering and Processing, 2005, 44:717-736
[9] HU Fan, LI Pengfei, GUO Junjun, et al. Evaluation, Developmet, and Validatio of a New Reduced Mechanism for Methane Oxy-Fuel Combustion[J]. International Journal of Greenhouse Gas Control, 2018, 78:327-340
[10] Tirado C, Jimenez S, Ballester J. Kinetics of CO2Gasification for Coals of Different Ranks Under Oxy-Combustion Conditions[J]. Combustion and Flame, 2013,160:411-416
[11] GUO Junjun, LI Xiangyu, HUANG Xiaohong, et al. A Full Spectrum K-Distribution Based Weighted Sum of Gray Gases Model for Oxy-Fuel Combustion[J]. International Journal of Heat and Mass Transfer, 2015, 90:218-226
[12] Chui E, Hughes P, Raithby G. Implementation of the Finite Volume Method for Calculating Radiative Transfer in a Pulverized Fuel Flame[J]. Combustion Science Technology, 1993, 92:225-242
[13] LIU Zhaohui, ZHENG Chuguang, XING Huawei. Radiative Properties of Residual Char and its Effects on Radiative Heat Transfer in Pulverized Coal Fired Furnaces[J]. Asia-Pacific Journal of Chemical Engineering, 2000,8(3/4):269-279
[14] WANG Lin, LIU Zhaohui, CHEN Sheng, et al. Physical and Chemical Effects of CO2 and H2O Additives on Counterflow Diffusion Flame Burning Methane[J]. Energy Fuels, 2013, 27:7602-7611
[2] Tan Y, Croiset E, Dougla, M A, et al. Combustion Characteristics of Coal in a Mixture of Oxygei and Recycled Flue Gas[J]. Fuel, 2006, 85(4):507-512
[3] Smart J P, O'nions P, Riley G S. Radiation and Convective Heat Transfer, and Burnout in Oxy-coal Combustion[J]. Fuel, 2010, 89(9):2468-2476
[4] GUO Junjun, LIU Zhaohui, HUANG Xiaorong, et al.Experimental and Numerical Investigations on Oxy-coal Combustion in a 35 MW Large Pilot Boiler[J]. Fuel, 2017,187:315-327
[5] GUO Junjun. LIU Zhaohui, WANG Peng, et al. Numerical Investigation on Oxy-combustion Characteristics of a200 MW_e Tangentially Fired Boiler[J]. Fuel, 2015, 140:660-668
[6]李鹏飞,徐敏义,王飞飞.精通CFD工程仿真与案例实战[M].北京:人民邮电出版社,2011LI Pengfei, XU Minyi, WANG Feifei. Proficiency in CFD Engineering Simulation and Cases[M]. Beijing:Posts&Telecom Press, 2011
[7] Fletcher T, Kerstein A, Pugmire R, et al. Chemical Percolation Model for Devolatilization. 3. Direct Use of Carbon-13 NMR Data to Predict Effects of Coal Type[J]. Energy Fuels, 1992, 6:414-431
[8] Petersen I, Werther J. Experimental Investigation and Modeling of Gasification of Sewage Sludge in the Circulating Fluidized Bed[J]. Chemical Engineering and Processing, 2005, 44:717-736
[9] HU Fan, LI Pengfei, GUO Junjun, et al. Evaluation, Developmet, and Validatio of a New Reduced Mechanism for Methane Oxy-Fuel Combustion[J]. International Journal of Greenhouse Gas Control, 2018, 78:327-340
[10] Tirado C, Jimenez S, Ballester J. Kinetics of CO2Gasification for Coals of Different Ranks Under Oxy-Combustion Conditions[J]. Combustion and Flame, 2013,160:411-416
[11] GUO Junjun, LI Xiangyu, HUANG Xiaohong, et al. A Full Spectrum K-Distribution Based Weighted Sum of Gray Gases Model for Oxy-Fuel Combustion[J]. International Journal of Heat and Mass Transfer, 2015, 90:218-226
[12] Chui E, Hughes P, Raithby G. Implementation of the Finite Volume Method for Calculating Radiative Transfer in a Pulverized Fuel Flame[J]. Combustion Science Technology, 1993, 92:225-242
[13] LIU Zhaohui, ZHENG Chuguang, XING Huawei. Radiative Properties of Residual Char and its Effects on Radiative Heat Transfer in Pulverized Coal Fired Furnaces[J]. Asia-Pacific Journal of Chemical Engineering, 2000,8(3/4):269-279
[14] WANG Lin, LIU Zhaohui, CHEN Sheng, et al. Physical and Chemical Effects of CO2 and H2O Additives on Counterflow Diffusion Flame Burning Methane[J]. Energy Fuels, 2013, 27:7602-7611