酸温滞后问题的PLC控制

PLC control of vitriol temperature lag

研究了大冶有色冶炼厂转炉烟气制酸系统吸收塔的阳极保护冷却器进口酸温相对SO2风机电流调整的滞后问题,测量了在人工调整时随时间变化的酸温并绘出了其变化曲线,导出了电流调整量的计算模型。研究结果表明:当酸温超过控制上限98℃时,SO2风机电流降低5A,热惯性升温不超过1.5℃,当酸温达到稳态时滞后时间不超过12min。此外,利用STEP7 Micro/WIN32软件在西门子S7 200系列CPU224的PLC上开发了解决酸温滞后问题的子程序块,控制酸温的误差小于0.1℃,满足了阳极保护冷却器的瞬时酸温不超过100℃的要求,减少了执行机构的动作频度。

This paper studies the lag problem of vitriol temperature in entrance relative to SO_2 (fan's) current adjustment in the cooler for protecting positive pole of the absorption tower of converter flue gas sour system. After measuresing the change of vitriol temperature with change of time when the manual regulation by a calculating model of current adjustment was established. The results show that when the vitriol temperature exceeds the upper limit temperature of 98 ℃, the SO_2 fan's current should be reduced 5 A, the rise of peak temperature for hot inertial will not exceed 1.5 ℃, and the vitriol temperature can be stabilized in 12 min. SETP 7-Micro/Win32 software grounded on 224 CPU of Siemens' S7-200 PLC is used to develop a subprogram which can solve the problem of temperature laged very well to control error less than 0.1 ℃, the subprogram can satisfy with the tube-crust anode protection cooler's requirement below 100 ℃ for temperature control, and greatly reduce the motion frequency of the executable machine.