Seeking Team Support to Overcome Gasket Replacement Challenges in Pipeline Valve Station

[GleeGloomGear]

I'm currently facing a challenging situation with a new pipeline project involving a valve station where we need to replace a gasket. Despite loosening all flange bolts, we have not been able to achieve the required gap for a proper gasket replacement.

Project Overview:
The valve station's design necessitates a specific gap for gasket replacement. To address this, we've excavated approximately 50 meters around the area to create sufficient working space and facilitate the process.

Current Equipment and Setup:

Lifting Equipment: We have employed a sideboom to lift the pipe. However, it appears that a single sideboom does not provide sufficient lift to achieve the necessary gap.
Flange Spreaders: We are equipped with 7 flange spreaders, each with a capacity of 14 tons, but even these powerful tools have not sufficed to open the flange to the required extent.
Challenges Encountered:

Insufficient Lift: The primary issue is the inadequate lift from the sideboom, which is critical for achieving the required separation at the flange.
Flange Rigidity: Despite the high capacity of our flange spreaders, the rigidity of the flange assembly under the existing conditions has proven to be a significant barrier.
Seeking Expert Advice and Suggestions:
I am reaching out to this knowledgeable community for insights or recommendations on how to successfully navigate this issue. Here are some specific questions:

Additional Lifting Strategies: Would the addition of another sideboom or alternative lifting equipment help in achieving the required separation? If so, what specific equipment would you recommend?
Enhanced Flange Spreading Techniques: Are there more effective techniques or tools for spreading the flange that might offer a better result than our current approach?
Experience with Similar Challenges: Has anyone encountered a similar situation and found innovative solutions or adjustments that proved effective?
Your expertise and any suggestions you could offer would be greatly appreciated as we strive to overcome these obstacles. Collaborative insights can often lead to innovative solutions, and I am hopeful that with your support, we can resolve this issue efficiently.

Thank you for your time and assistance.

 

[1503-44]

You might want to mention

Pipe Diameter, wall thickness and flange type.
Depth of pipeline.
Elbow details.

What is the temperature of the pipe now?
What was the installation temperature?

Have you thought about cooling the pipeline, or trying to do this during cooler hours of the night, or delaying the work entirely until winter temperatures arrive?



--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Cooling sounds like your only way option.

Liquid nitrogen or CO2 would do but try not to go below - 30.

If the pipeline is dead straight, axial forces could reach over 150 tonnes easily.

But not quite sure what your side boom is doing, but contraction is better than having to take a cutter to it....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GleeGloomGear]

thank you for the support and clarification,
the pipe size is 56"
thickness is 0.8 inch
material: Carbon steel
Grade: X70
to clarify these are not elbow bend, but field bend.

for the pipe temperature I do not have the exact temperature, but the weather temperature at day is around 45 C and at night it reach to 36 C.

for the activates, I do not think we could delay it to the winter time, but we are working at night when the temperature is lower. we were working good without issues, however, for this location we have faced this issue

 

[1503-44]

56x0.8" No way are you going to move these flanges with anything. Cooling is your only option, other than cutting in.

36° is way better than 45, but likely is still very much too high.

What clearence distance do you need?
If you can cool 50m of pipe to 0°C, it will get you about 25mm.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Heaviside1925]

disclaimer.... zero pipeline experience (honestly a little but LI and 44 are much more exp).
First agreement that cooling sounds like you best option. Secondly, I assume this delay is costing $$$$$ ever hour out of service on top of having a crew on site, do you have an alternated plan, if cooling doesn't work or is not viable?
Even with the spreaders and equipment described, it doesn't sound like much of a match against a stuck flange on a 56x0.8" pipeline. Is this a spool piece? Does your side boom have the capacity to lift the spool piece? I may be out on a limb here and I'm sure others will tell me my idea has no merit if required. Could the flange faces themselves be causing the resistance as opposed to just the pipe stress/forces? If the flange faces are an issue, would a torsional force break them loose? I'm thinking something like a deep beam moment arm to create a torque about the flange faces, maybe rubbish but thought I'd throw it out.

 

[GleeGloomGear]

now after loosening the flange between the flange faces is around 16 mm. I only need around 25 mm to remove and install the new gasket.
But speaking for cooling what could the possible way to the pipeline, and how we could do that safely with effecting the material structure of carbon steel.

regarding a torsional force, would please elaborate more about the idea

 

[LittleInch]

You're coming up as KSA?

You could chill down a water tanker and spray water all over it or use liquid co2 ir liquid nitrogen. Just measure metal temp and don't go below about minus 30. Just don't cool unevenly.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

I think LI means not to cool the bottom of the pipe while leaving the top warm. That would tend to curve the pipe down. You must try to cool around the entire diameter to the same temperature to keep the pipe straight. Cold water will be difficult, as it cools the bottom of the pipe first and might drain into the sand. Maybe blocks of ice could be placed around the diameter. You could place ice blocks, or dump crushed ice around it in the Trench, two or 3 meters of length at a time.

That's a lot of ice. I want pictures.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Heaviside1925]

weather temperature at day is around 45 C and at night it reach to 36 C.

I missed this. If you're in KSA, I think you could get a long way with evaporative cooling. Looks like 36 C and 9% humidity in Riyadh right now at 11pm. Working at night with just forced air water mist, I think you could down around 10 C which might be enough.

 

[1503-44]

Unless he's in Alkhobar, or Jeddah. Its pretty humid anyway, but rises at night. Dubai is horrible. I had to jump stop at an air conditioned ATM machine lobby to survive a 750m walk to the restaurant zone at 9pm.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

I can only assume this is an RTJ flange?

That's why a lot of people now use RF, even at class 900 because it's such a bitch to spread a flange to get the ring in.

What is the plan view of this valve and the 100m of pipeline either side?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Have you managed to get it out?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GD2]

OP,
Pipeline valve stations/pig stations typically face the problem you are facing. This is normal. This is due to transition of the pipeline from restrained to semi/unrestrained pipeline when the U/G pipeline transits to A/G.
LI and -44 has suggested to cool down the line to replace the gasket.
If you are using API 5L X70 Piping, the MDMT for the 0.80 inch thick line will be -8C with full line pressure. Obviously, you have isolated the line for maintenance with no pressure on the section. you can safely cool the section to -48C without any impact testing.
To avoid this situation of lock-up due to excessive thermal stress at the A/G portion, many Owners suggests to use a Z-bend at the transition instead of single S-bend. This is in addition to the virtual anchor point, the designers use at the transition.

GDD
Canada

 

[1503-44]

Offset bends in 56" pipe would need very large dimensions to get any flexibility.

An offset like this one can cause very high bending moments from expansion forces, which can misalign flanges and destroy electrical isolation joints. It would probably have been better not to have put the valve above ground, so that bending moments are not created by the valve's vertical offset from the main pipeline centerline. Yes, even with flanged joints.

Best of all is to use weld end valves and place isolation joints or fittings somewhere else, well away from regions subject to high bending moments. Riser bends like these seem to be a favorite place to put flanges and isolation joints. I see these everywhere, but it is not good practice. It is typically the highest bending moment region in any pipeline.





--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."