针对连续热镀锌生产线辐射管退火炉工艺段,以能量平衡为基础,采用三元法建立了炉气、炉壁、辐射管表面和带钢表面的能量方程组,屏蔽了模型段间能量交换,以加速计算效果,满足实际动态调整需要。针对厚带钢引入内部导热方程,通过与带钢表面热流耦合,采用显格式有限差分法求解带钢内部及炉内温度场,结果与现场检测值基本一致,验证了模型的正确性。在追求最高生产效率的假设条件下,离线模拟得到优化工艺参数。结果表明,来料带钢厚度为2 mm时匹配运行速度达到传动机限速200 m/s。安全运行条件下,加热一段开启尽可能大燃料流量,约为255~260 L/min,二段通过适当减小流量使产品升温同时缩小截面温差并提高燃料利用率,2 mm带钢对应最小温差0.18℃,二段燃料流量降至174 L/min,对应最小单位能耗1049 L/t,5 mm带钢对应最大温差0.60℃,二段燃料流量为230 L/min,对应最大单位能耗1071 L/t。
Based on the energy balance, the energy equations of the furnace gas, furnace wall, radiant tube surface and strip surface were established by the ternary method for radiation tube furnace (RTF) of process section of the continuous hot-dip galvanizing line, and the energy exchange between the model sections was shielded to achieve the effect of accelerating calculation and the dynamic adjustment need was satisfied. According to the internal heat conduction equation of thick strip steel, the internal temperature field of the strip and the temperature field in the furnace were obtained by the finite-difference method, which was consistent with the on-site detection value. The correctness of the model was verified. Under the assumption of pursuing the highest production efficiency, offline simulation results of an optimized process parameters were achieved. As a result, when the thickness of the incoming strip was 2 mm, the matching running speed reached the speed limit value of the conveyor of 200 m/s. The first heating section opened the maximum fuel flow rate of 255~260 L/min. The second section increased the product temperature while reducing the cross-section temperature difference and improved fuel utilization by reducing the flow rate. 2 mm strip steel corresponding minimum temperature difference was 0.18℃, fuel flow reduced to 174 L/min, corresponding minimum unit energy consumption was 1049 L/t. The maximum temperature difference of 5 mm strip was 0.60℃, the second section fuel flow was 230 L/min, corresponding maximum unit energy consumption was 1071 L/t. Reasonable determination of process parameters was conducive to heating the strip and improving the overall production efficiency.
[1] 顾国成,刘邦津.中国腐蚀与防护丛书:热浸镀[M].北京:化学工艺出版社,1988:2-6
[2] 李九岭.带钢连续热镀锌(第2版)[M].北京:冶金工业出版社,1995
[3] 张竑.现代热镀锌机组连续退火技术[J].武钢技术,1999,37(4):51-54
[4] 朱立.钢材热镀锌[M].北京:化学工艺出版社,2006
[5] 韩小良.辐射管炉炉膛辐射换热计算方法[J].工业炉,2000,22(1):55-59
[6] 马国和.现代热镀锌连续退火炉炉型选择及特性分析[J].工业炉,1998,20(1):12-17
[7] 吴光治.带钢连续热镀锌与退火炉的技术进步[J].工业炉,2006,28(2):19-21
[8] 张启富,刘邦津,黄建中.现代钢带连续热镀锌[M].北京:冶金工业出版社,2007:1-3
[9] 吴彬,陈海耿,李本文.连续加热炉三元在线控制数学模型[J].工业炉,1999,21(2):34-37
[10] Hu Y, Tan C K, Broughton J, et al. Development of Transient Mathematical Models for a Large-scale Reheating Furnace Using Hybrid Zone-CFD Methods [J]. Energy Procedia, 2015, 75: 3076-3082.
[11] Zhou W, Qiu T. Zone Modeling of Radiative Heat Transfer in Industrial Furnaces Using Adjusted Monte Carlo Integral Method for Direct Exchange Area Calculation [J]. Appl. Therm. Eng., 2015, 81: 161-167.
[12] Guo Y, Dai F, Yang S. A Model Study of Thermal Characteristics of Decarburization Annealing Furnace for Silicon Steel Strip [J]. Appl. Therm. Eng., 2016, 99: 537-544.
[13] 韩小良,鲍戟.带钢连续退火炉加热室传热计算方法[J].北京科技大学学报,1993,15(4):353-357
[14] 杨世铭,陶文铨.传热学(第三版)[M].北京:高等教育出版社,1998,380-382
[15] 韩小良.辐射管炉炉膛辐射换热计算方法[J].工业炉,2000,22(1):55-59
[16] ]赵渭国,杜涛等.火焰炉设计[M].沈阳:东北大学出版社,2005:1-7
[17] 宁宝林,杨泽宽,陈海耿.钢锭液芯加热、液芯轧制热状态数学模型(之二)[J].冶金能源,1985,4(7):34-40