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换热器是化工厂一种常见的换热设备,换热器的出口温度往往要求较高。在某县化肥厂生产磷酸钾的过程中,换热器出口温度控制原来用的是简单控制系统。如用冷却水的流量作为控制手段,其调节回路的动态响应较为缓慢,而用磷酸钾的流量作操作变量,虽然响应较快,但产品质量不能完全保证。笔者综合上述两类操作变量各自的优点,使磷酸钾出口温度得到了很好的控制,这就是双重控制系统。一、控制方案换热器出口温度控制系统如图所示。当偏差出现时,DTL-2100温度调节器输出的4～20mA的信号直接送到带电-气转换器的
Heat Exchanger is a common chemical plant heat exchange equipment, the outlet temperature of the heat exchanger often require higher. In a county fertilizer plant production of potassium phosphate process, the outlet temperature control of the original heat exchanger is a simple control system. Such as the use of cooling water flow as a means of control, the dynamic response of its regulating circuit is relatively slow, and the flow of potassium phosphate as operating variables, although the response is faster, but the product quality can not be fully guaranteed. The author combines the advantages of the above two types of operating variables, the outlet temperature of potassium phosphate has been well controlled, which is a dual control system. First, the control scheme heat exchanger outlet temperature control system as shown. When the deviation occurs, DTL-2100 temperature regulator output 4 ~ 20mA signal directly to the charged - gas converter