What are some good methods to prevent coking in the temperature-changing sleeve of the riser?
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To measure temperature changes in the lift pipe, K-type thermocouples are used, protected by 316 stainless steel sleeves to prevent erosion. However, severe coking occurs between the 316 protection sleeve and the thermocouple sleeve, making it difficult to remove them during each maintenance task. A similar problem often occurs with the temperature measurements of the oil and gas main at the top of the tower, which is quite troublesome. I wonder if anyone has encountered this before, and what good preventive measures there are
Minimize the gap between the protective sleeve and the thermocouple sleeve; if it cannot be removed during maintenance, try using steam for cleaning first and then a pneumatic hammer!
A pneumatic hammer cannot be used to get it in; the insertion depth of the thermocouple is 600–700 MM. Each time it needs to be removed, a cutting tool is used for heating, and two jacks are employed to push it out as a support. Therefore, during each maintenance session, at least one thermocouple sleeve needs to be replaced. If things go wrong, the 316 sleeve of the lift pipe also has to be replaced, which is very troublesome – welding alone takes 24 hours, and X-rays are also required. If the device uses slightly poor-quality oil just once, we have to spend half a day dealing with it. Headache