论文部分内容阅读
某电厂一期(2×600 MW)1号煤粉锅炉实际运行中长期存在二次汽(再热汽)欠温、过热器减温水过量、水平烟道入口左右侧汽温偏差大的问题而对锅炉运行的安全性和经济性带来了不利影响,急需对此进行全面分析并治理改造。经初步理论分析及数值模拟研究,决定对过热器分隔屏受热面进行截短改造。为了掌握分隔屏截短改造前后炉膛出口(水平烟道入口)烟气流场的变化情况,特别是在水平烟道入口是否形成烟气走廊,针对分隔屏分别截短1、2及3m前后的炉内等温流场进行了数值模拟研究,特别关注水平烟道入口流场的变化情况。根据数值模拟计算和热力校核计算结果的综合分析与对比,对分隔屏进行了截短2 m改造。实际运行表明,各负荷下二次汽温达到了设计值、过热器减温水平均下降了30 t/h左右、左右侧汽温偏差明显减少、炉膛出口(水平烟道入口)没有形成烟气走廊,改造取得了满意的效果。该改造方式对国内存在有类似问题的锅炉具有重要的参考意义。
In the actual operation of the No. 1 coal-fired boiler of a power plant (2 × 600 MW), there is a problem that the temperature deviation of the secondary steam (reheat steam) is far lower than the temperature of the superheater and the temperature of the left and right sides of the horizontal flue inlet is large This has adversely affected the safety and economy of the operation of the boiler and urgently needs a comprehensive analysis and management reform. After preliminary theoretical analysis and numerical simulation studies, it is decided that the heating surface of the superheater partition screen should be short-cut. In order to grasp the change of the flue gas flow field at the exit of the furnace (horizontal flue inlet) before and after the truncated screen was cut off, especially if the flue gas corridor was formed at the inlet of the horizontal flue, the separation screens were respectively truncated before and after 1, 2 and 3 m The isothermal flow field in the furnace was numerically simulated, with special attention paid to the changes of the flow field at the entrance of the horizontal flue. According to the comprehensive analysis and comparison of numerical simulation results and thermal calculation results, the split screen was reconstructed by truncation of 2 m. The actual operation shows that the secondary steam temperature reaches the design value under each load, and the desuperheater temperature drops by about 30 t / h, the deviation of the steam temperature on the left and right sides is obviously reduced, and the flue gas corridor is not formed at the furnace outlet (horizontal flue inlet) , Transformation achieved satisfactory results. The way of reconstruction has important reference meaning for domestic boiler with similar problems.