Mail
Chinese
English
The cracking furnace outlet temperature control system using thermocouple as the measuring element, the fuel flow control to adjust the outlet temperature in the running temperature indication value is low, when the control valve opening increases when the fuel temperature indicator changes slowly.
Fault inspection and analysis: temperature regulation system failure phenomenon of such a comparison is difficult to judge, the regulating system is insensitive to many factors, such as P, I, D regulator parameters are not appropriate, the ratio of P and I integral role is not enough, regulating margin control valve is not enough, such as the extraction amount, no valve diameter change valve is small, or the valve has a blocking phenomenon, moreover is the temperature sensor lag, resulting in valve system is not sensitive, after inspection, found that the thermocouple core length is not enough, not into the protection pipe at the bottom, so that there is a gap between the heat end of thermocouple and the top of the casing, because the air thermal resistance and the heat transfer performance is poor, resulting in great measure lag, large time lag measuring system PID controller is difficult to improve the quality of regulation, so the temperature changes slow phenomenon, in addition Measuring points are changed. If the temperature distribution within the device is not uniform, then the temperature of each point will have difference, moreover, the casing temperature is passed on to the end of the end of thermocouple air layer, heat loss, thermocouple temperature is lower than the end of T1 protective sleeve top temperature of T0, so the indication is lower.
Troubleshooting: according to the protective sleeve insertion depth of thermocouple configuration length of the thermocouple has been inserted into the protective sleeve tears end until the top, want to touch, after the processing, the normal temperature indicator, regulating system of quality indicators also improved.
