9 replies to this topic

[Yongnat]

Does anyone have experience with hydrogen transmission pipeline design?

 

I am working on a 50 mile long hydrogen transmission pipeline and trying to determine pipe diameter. Pressure drop is not the controlling factor for my case. I just want to know if there is any recommended velocity criteria for hydrogen pipelines. Based on API 14E or Norsok P-001, the erosional velocity could be very high. But API 14E also stated that there could be noise concern when velocity is above 60 ft/s. Should I keep the velocity below 60 ft/s? If we were only to keep the flow sub-sonic and avoid erosion, the velocity can be much higher than 60 ft/s. I also know for certain gas pipeline such as steam pipelines, people use very high velocity (e.g > 100 ft/s). How about hydrogen?

 

Any thought?

 

Thank you!

[Bobby Strain]

I don't know how you determined that pressure drop is not a factor. Long pipelines are usually designed on optimizing initial cost vs operating cost. For which pressure loss is an important factor.

 

Bobby

[Yongnat]

I mentioned the pressure drop is not the control factor in my case is because I had sufficient supply pressure to meet delivery pressure requirement with even smaller pipe sizes for which the velocity will be higher than 60 ft/s. I hope that clarifies. My question is can I go higher than 60 ft/s without causing other problems that I am not aware of. 

Edited by Yongnat, 12 April 2016 - 05:19 PM.

[Bobby Strain]

Is this a real project? Or just an exercise.

 

Bobby

[Padmakar Katre]

I mentioned the pressure drop is not the control factor in my case is because I had sufficient supply pressure to meet delivery pressure requirement with even smaller pipe sizes for which the velocity will be higher than 60 ft/s. I hope that clarifies. My question is can I go higher than 60 ft/s without causing other problems that I am not aware of. 

 

By this explaination, do you mean that you are making a tap in the existing network and putting the lateral pipe for new users. If the pressure at supply is not governed by this then velocity could be a criteria, you can check/compare this velocity with the sonic velocity to arrive at the conclusion. API RP-14E gives RhoV2 criteria of 10000 kg/m-s2 for conitineous and 22500 kg/m-s2 for intermittent, this is more applicable where you have two phase which can lead to erosion if velocities are high however in your case it's just the hydrogen gas, errosion is unlikely.

[Yongnat]

To Bobby:

 

This is a real project connecting two refineries. The supply pressure is given and the delivery pressure requirement is specified. 

[Mahdi1980]

Yongnat

 

Most of the time, it is better to use velocities below the sonic velocity to avoid making sound and some other problems in the pipeline.

Maybe 15 m/s is appropriate.

However, reasonable pressure drop throughout the pipeline is the design key.

So, for a secure design, you can use Aspen Hydraulic by defining the downstream (end user) pressure and the length and elevation changes in the pipeline to meet the source pressure.

In this software, as you have a certain flowrate of Hydrogen, by changing the diameter of pipeline you can find the best diameter.

Once, check the result with my suggested velocity.

D= sqrt((Q/3600/15)*4/3.14)

Where Q is gas flow rate in m3/hr

Edited by Mahdi1980, 13 April 2016 - 09:53 AM.

[Yongnat]

Mahdi,

 

Thank you for your response and recommendation. The sonic velocity for hydrogen is really high. Keeping the velocity below sonic velocity is not a problem. I do have software for the simulation. With a 10'' diameter pipe, I still have more than adequate delivery pressure but the line velocity reaches above 60 ft/s. Is this considered to be typical for a hydrogen pipeline?  

[Bobby Strain]

Maybe you can tell us the composition, flow rate and initial pressure. Along with required delivery pressure. We don't normally design for a limiting velocity, but use other criteria.

 

Bobby

Edited by Bobby Strain, 13 April 2016 - 01:01 PM.

[Yashman]

Velocity and Pressure drop both the criteria are utmost important to be taken care during hydraulics. In your case since Hydrogen is being handled we can firstly size based on velocity which shall not be more then 50% of erosion velocity or as per my personnel experience we can straight away take a velocity around 15 m/sec(cal. based on density of 0.078). and check delta pressure accordingly.Also momentum criteria may be taken if two phase flow has been observed.