MR (Mixer refrigerant) Expander in APCI process (C3MR)

[gasnaturel]

Hi everyone,
I need Help in LNG Plant,
We have Started a new LNG LNG PLANT (C3MR) process, and when we want start the LNG MR EXPANDER, We had a problème with temperature in every stage of the main Heat Exchanger (APCI), so it's coming warm in every pass on the MR Cycle, The problem is that we can't increase the flow passing through the Expander, and we just work less than 100% of capacity.

after investigating we found that the Plant is tripped before by this equipment (Vibration), they worked on it, and they found that many bearing are broken because the less of flow lubrification with MR (Mixed Refrigerent) passed trought the bearings, they add a new hole to passe much more flow trough in,
Now please, I need to know if we made a change in it like this what's the consequence in his design, and what he affect in MR composition?


Plz if u need other explanation just ask me
Thank you

 

[compconfessor]

Is there any update to this? Is it correct that the lube oil system or bearing feed ports for the expander were not designed correctly? Is this an APCI expander?

 

[gasnaturel]

This is an Ebara Expander to APCI process, we want t know why the flow is limited? and why the power is coming down? we can't arrive to use it at 100%

 

[compconfessor]

I was thinking this might be a vapour expander however this sounds like a liquid expander where the process fluid is also the lubricant. Unfortunately I am not familiar with this design. It makes sense that lower flow will result in lower expander power to the generator, however it seems possible reasons for lower expander flow might include things like:

Inlet guide vanes are already fully open or are stuck
The available differential pressure is lower than expected
The impeller stages are not sized properly

Sorry I can't provide better suggestions. Hopefully Ebara and/or APCI will continue to troubleshoot this situation.

 

[gasnaturel]

Thank you very much