烟气飞灰对SCR脱硝催化剂磨损数值模拟
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摘要
采用CFD数值模拟软件对不同烟气流速、不同烟气入射角下催化剂不同磨损部位的磨损规律进行了研究和分析,并对催化剂的年磨损率进行了预测。结果表明:催化剂端面磨损率远远大于壁面,在不同烟气流速下,催化剂磨损率沿孔道方向的变化基本一致,呈中间较小、端面附近较大的规律;在不同烟气入射角下,受烟气正面磨损结构面的磨损率在距入口约0.04 m内与烟气入射角成正比,在0.04 m以后与烟气入射角成反比;受烟气背面磨损结构面的磨损率沿管道方向在入口附近迅速减小,后增加直至出口;不同烟气入射角下的端面磨损率随着烟气入射角的增大而减小;在设计工况下运行的脱硝系统,催化剂的年磨损率可以忽略不计,但当烟气流速为11 m/s时,催化剂孔壁在一年内就会磨穿,在实际运行过程中,应降低烟气流速并选择合理的烟气入射角。
Numerical simulations were conducted to study and analyze the wear law of SCR denitration catalysts in various areas at different flue gas flow rates and incident angles using CFD software, and subsequently the annual wear of the catalysts was predicted. Results show that the wear rate at the end face of catalyst is much higher than that of the wall. At different flue gas flow rates, the wear rate exhibits the same variation law along the direction of the channel, which is relatively small in the middle region and large in the vicinity of the cross section. At different incident angles, the wear rate of front surface is proportional to the incident angle within 0.04 m away from the inlet, and is inversely proportional to the incident angle beyond 0.04 m; the wear rate of back surface decreases rapidly near the inlet along the direction of the channel, which then increases gradually up to the outlet. At different incident angles, the wear rate of end face reduces with the rise of incident angle. When the denitration system operates under design conditions, the annual wear of the catalyst is negligible, but when the flue gas flow rate gets up to 11 m/s, the wall surface of the catalyst would be worn through within one year, therefore in actual operation process, the flue gas flow rate should be reduced and the incident angle should be reasonably determined.
Numerical simulations were conducted to study and analyze the wear law of SCR denitration catalysts in various areas at different flue gas flow rates and incident angles using CFD software, and subsequently the annual wear of the catalysts was predicted. Results show that the wear rate at the end face of catalyst is much higher than that of the wall. At different flue gas flow rates, the wear rate exhibits the same variation law along the direction of the channel, which is relatively small in the middle region and large in the vicinity of the cross section. At different incident angles, the wear rate of front surface is proportional to the incident angle within 0.04 m away from the inlet, and is inversely proportional to the incident angle beyond 0.04 m; the wear rate of back surface decreases rapidly near the inlet along the direction of the channel, which then increases gradually up to the outlet. At different incident angles, the wear rate of end face reduces with the rise of incident angle. When the denitration system operates under design conditions, the annual wear of the catalyst is negligible, but when the flue gas flow rate gets up to 11 m/s, the wall surface of the catalyst would be worn through within one year, therefore in actual operation process, the flue gas flow rate should be reduced and the incident angle should be reasonably determined.
引文
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[7] 盛波, 韦红旗, 朱亚迪. 脱硝系统内横梁结构对催化剂磨损的影响[J]. 动力工程学报, 2015, 35(6): 489-494. SHENG Bo, WEI Hongqi, ZHU Yadi. Impact of beam structure on catalyst abrasion in the denitrification system[J]. Journal of Chinese Society of Power Engineering, 2015, 35(6): 489-494.
[8] 刘东雨. 200 MW发电机组锅炉氮氧化物治理技术改造研究[D]. 大连: 大连理工大学, 2016.
[2] 李锋, 於承志, 张朋, 等.高尘烟气脱硝催化剂耐磨性能研究[J]. 热力发电, 2010, 39(12):73-75. LI Feng,YU Chengzhi,ZHANG Peng,et al.Study on abrasieveness of catalyst used for denitrification in flue gas with high dust content[J]. Thermal Power Generation, 2010, 39(12):73-75.
[3] 姜烨, 高翔, 吴卫红,等. 选择性催化还原脱硝催化剂失活研究综述[J]. 中国电机工程学报, 2013, 33(14):18-31. JIANG Ye,GAO Xiang,WU Weihong,et al.Review of the deactivation of selective catalytic reduction De NOx catalysts[J]. Proceedings of the China Electrical Engineering, 2013, 33(14): 18-31.
[4] 徐秀林, 吴卫红, 柳东海, 等. SCR蜂窝状脱硝催化剂磨损数值模拟研究[J]. 应用化工, 2015(6):986-990. XU Xiulin,WU Weihong,LIU Donghai, et al.Numerical study of erosion on honey comb SCR catalyst[J].Applied Chemical Industry,2015(6):986-990.
[5] 安敬学, 王磊, 秦淇, 等. 电站锅炉脱硝系统催化剂磨损数值模拟[J]. 锅炉技术, 2016, 47(2): 32-38, 42. AN Jingxue, WANG Lei, QIN Qi, et al. Study and governance of SCR catalyst attrition based on the numerical simulation and testing[J]. Boiler Technology, 2016, 47(2): 32-38, 42.
[6] 金理鹏, 王勇, 宋玉宝, 等. 烟气参数对选择性催化还原系统设计的影响分析[J]. 热力发电, 2013, 42(8): 124-127. JIN Lipeng, WANG Yong, SONG Yubao, et al. Effect of viscous fly ash on the SCR system design[J]. Thermal Power Generation, 2013, 42(8): 124-127.
[7] 盛波, 韦红旗, 朱亚迪. 脱硝系统内横梁结构对催化剂磨损的影响[J]. 动力工程学报, 2015, 35(6): 489-494. SHENG Bo, WEI Hongqi, ZHU Yadi. Impact of beam structure on catalyst abrasion in the denitrification system[J]. Journal of Chinese Society of Power Engineering, 2015, 35(6): 489-494.
[8] 刘东雨. 200 MW发电机组锅炉氮氧化物治理技术改造研究[D]. 大连: 大连理工大学, 2016.