浅谈乙烯裂解炉COT的有效测温方法

Effective Temperature Measurement Method of Ethylene Pyrolysis Furnace COT

乙烯裂解炉炉膛出口温度(简称COT)的测量准确性直接关系到乙烯的收率,所以测量COT的精确度十分重要。对比现场使用的表面式和插入式热电偶,发现表面式热电偶较插入式热电偶测量温度偏低30℃以上,不适合大批量使用表面式热电偶作为COT的测温。而分析不同结构的插入式COT热电偶,包括早期的进口产品和之后的国产改造产品,插入式热电偶的套管结构形式对热电偶的测量精度影响较大,对比了5种插入式热电偶,选出一种测量精度高且使用寿命长的插入式热电偶。

Coil outlet temperature of ethylene pyrolysis furnace, hereinafter referred to briefly as COT, is the main factor affecting yield of ethylene, so accuracy of COT measurement is important. After comparing different surface and insertion thermocouples, we find the temperature measured by surface thermocouples is 30℃ lower than insertion ones. Massive using surface thermocouples are not applicable to COT measurement. By analyzing 5 different structure insertion COT thermocouples, including early imported ones and domestically renovated ones, we come to the conclusion that the thermowell structure of insertion thermocouples affects the measurement accuracy, and select one high measurement accuracy insertion thermocouple with comparatively long lifetime.