What type of seal is suitable for the coke outlet of a coking tower?
Thread Content
Hello, experts! In recent years, there have been many issues with delayed coking units; here we will discuss what type of sealing is the most reliable and cost-effective to use at the tar outlet As far as I know, metal ring gaskets are basically used for sealing. However, it is very difficult to control the precision when machining trapezoid grooves of such large diameters (mismatches in the center distance between the upper and lower openings, deformation due to heat treatment of the equipment, and out-of-roundness). Last July, the flange and gasket at the tar outlet of a delayed coking unit (which came online in 2003) did not fit properly; after measurement, it was found that the trapezoidal groove on the flange had shrunk by 4.5 mm overall. We have also considered using the inner flat surface of the trapezoidal groove as the sealing surface, adopting a flat-seal design, and using wave-patterned composite gaskets. However, since the device needs to be opened for coke removal on a daily basis, using wave-patterned composite gaskets means replacing them almost every day; even if A3 steel gaskets are used, the cost per piece is several hundred yuan. Let’s discuss here whether the flanges at the coke outlet of delayed coking units might shrink as a whole after being exposed to temperatures of 500–600°C and subsequently cleaned with high-pressure water ? ? Please help this little sister
In my personal opinion, metal steel pads are the best choice. Obviously, the wavy tooth pads are too expensive; they have to be replaced every time the coke is cleaned, and they are also costly ； Our company’s three coking units use metal gaskets for all 10 coke ovens ； Deformation of the sealing surface due to prolonged use can be addressed by local replacement.
Metal steel pads represent a reasonable option in terms of overall cost and reliability.