The temperature of dissolved salt is always inaccurate
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Our factory that makes phthalic anhydride has very strict requirements on the temperature of dissolved salt, but the meter is always not allowed to be around 358-359 degrees. Our system is remote controlled by Zhejiang University Central Control DCS and should be fine. However, the value measured by the thermocouple feels very inaccurate and fluctuates greatly. I don’t know what is the influence.
The temperature error of industrial thermocouples is generally relatively large. The allowable error at the 358°C point is plus or minus 2.685 degrees, which is a large error. It is recommended to use a thermal resistor, which has high measurement accuracy. It is best to use a three-wire Pt100
What should the normal temperature be? Check the temperature compensation.
1. The temperature measurement error of thermocouples is relatively large. If the accuracy requirements are high, it is recommended to use pt100 thermal resistors. 2. The large error may be due to the adsorption of some process media on the protective sleeve of the galvanic couple, causing heat conduction to lag. It is best for the poster to first find out the reasons that affect the measurement error and then deal with it.
Is it the salt temperature on the molten salt pipeline or the temperature in the reactor? I rarely use thermal resistors when making maleic anhydride, but only use thermocouples. It seems that your situation has never happened.
Hello everyone, I am a friend from the fourth floor on the first floor. Your words reminded me that you said it is possible that the molten salt (55% KNO3 and 45% NaNO2) used as the media in the process has been adsorbed, but you need to add salt to check, and it will cost at least 200,000. Friends on the fifth floor, are you making phthalic anhydride or maleic anhydride? As long as you know the reactor, it is the temperature of the salt channel in the reactor, not the bed temperature. Anyway, thank you all. It is because the instrumentation skills of our factory are not good enough.
Hello: I also make maleic anhydride, can we communicate? Add me QQ907005467