Danlap
Mechanical
- Sep 17, 2013
- 309
Good day All,
Hope everyone are well. Need some advise on how to mitigate gland leakage due to eroded stem on gate valve? Some out of the box (temporary) solution, as this gate valve cannot be removed from the line until 2023.
Long story short: 8"-300# slide gate valve located directly under the catalyst reactor. Valve is Normally Close, we drop around 5,000 tons catalyst at around 650degC at 3-4 bar once every two weeks (this is the only circumstances when valve must be fully open).
Unfortunately, 4-5 months ago on several catalyst drop activities, our operators thought valve was already fully open since it was hard to operate around 60-70% opening. As a result, some section of the spindle were eroded due to totally exposed to a flowing catalyst. Coating ripped of and more.
Original stem diameter is 42 mm, packing configuration (bottom to top) are carbon ring, pre-compressed graphite ring, graphite yarn with inconel wire (6ea).
Even though we re-packed the packing after the drop, due to existing eroded stem (smaller dimension and really rough surface), it will damage packing and/or simply do not seal and causing a considerable amount of catalyst leakage with H2S (around 10 liter) per hour. Hence hazard to operator when they are in the process of opening the valve.
Make an extension box (install another set of packing higher location for undamage surface)?? Or any other ideas / reference is highly appreciated?
Condition is not ideal, but shutting down this plant for proper stem replacement is not yet an option.
Yes, I made sure that now valve can be fully open so that erosion is not worsen. Valve stuck was due to some rubber caught in between the gearbox![[sad]](/data/assets/smilies/sad.gif "[sad] [sad]")
Thank you,
Kind regards,
MR
All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected
Hope everyone are well. Need some advise on how to mitigate gland leakage due to eroded stem on gate valve? Some out of the box (temporary) solution, as this gate valve cannot be removed from the line until 2023.
Long story short: 8"-300# slide gate valve located directly under the catalyst reactor. Valve is Normally Close, we drop around 5,000 tons catalyst at around 650degC at 3-4 bar once every two weeks (this is the only circumstances when valve must be fully open).
Unfortunately, 4-5 months ago on several catalyst drop activities, our operators thought valve was already fully open since it was hard to operate around 60-70% opening. As a result, some section of the spindle were eroded due to totally exposed to a flowing catalyst. Coating ripped of and more.
Original stem diameter is 42 mm, packing configuration (bottom to top) are carbon ring, pre-compressed graphite ring, graphite yarn with inconel wire (6ea).
Even though we re-packed the packing after the drop, due to existing eroded stem (smaller dimension and really rough surface), it will damage packing and/or simply do not seal and causing a considerable amount of catalyst leakage with H2S (around 10 liter) per hour. Hence hazard to operator when they are in the process of opening the valve.
Make an extension box (install another set of packing higher location for undamage surface)?? Or any other ideas / reference is highly appreciated?
Condition is not ideal, but shutting down this plant for proper stem replacement is not yet an option.
Yes, I made sure that now valve can be fully open so that erosion is not worsen. Valve stuck was due to some rubber caught in between the gearbox
Thank you,
Kind regards,
MR
All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected
