Increase pressure in a compressor
Increase pressure in a compressor
(OP)
Hi.
What are the consequences if we need to increase the current parameters in an over-hung centrifugal compressor as the following :
P1 = 0.15 Bar -> 0.5 Bar
P2 = 0.60 Bar -> 0.8 Bar
These changes will be done by installing some constrains in the lines. So, what do you think, will these changes will effect the compressor's health ?
What are the consequences if we need to increase the current parameters in an over-hung centrifugal compressor as the following :
P1 = 0.15 Bar -> 0.5 Bar
P2 = 0.60 Bar -> 0.8 Bar
These changes will be done by installing some constrains in the lines. So, what do you think, will these changes will effect the compressor's health ?





RE: Increase pressure in a compressor
At the very least, I suggest you will have to consider having the surge line remapped.
RE: Increase pressure in a compressor
Well, the pressure mention is in BarG.
My main concern is that, will this modification effect the mechanical components of the compressor (carbon seal, journal brg, thrust brg, gearbox, motor, etc.) ??
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
as far as mechanical internal parts, there are numerous internal parts to refer to.
good luck!
-pmover
RE: Increase pressure in a compressor
how can you guess such figures without knowing the shape of perf curves?
thks
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
I guess it is not fully correct. At least Pin, Tin and MW are required figures. For example with High Mol. weight application for instance, the shape Head vs. Flow drastically change then it is for low mol. weight. Small % increase in flow will drastically reduce the head. Turndown is lower.
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
Basically with the changes, you run with quite lower head and therefore lower speed (less 70 % ??).
Very generally speaking, you need to check new operating speed versus the Critical ones (speration margin) versus code (API if applicable?)
There are other points to check...you need to revert to compressor Mfg (even I would doubt of feasibility...but just w/o tecnical details this still just a feeling..)
Regards
Wimple
RE: Increase pressure in a compressor
Is there any way that I can make sure that the increase in pressure won't effect the internal components of the compressor ?!
wimple, "lower speed" do you mean flow speed ?!
Can you please elaborate more ?
I really appreciate your help guys
RE: Increase pressure in a compressor
RE: Increase pressure in a compressor
Do you think the increased pressure will increase the probability of thrust bearing failure ?!
RE: Increase pressure in a compressor
Thrust = inlet pessure * effective area of inlet - outlet pressure * Effective area of outlet.
You should be able either measure values like pressures and the thrust forces which is will be a pressure on the thrust bearing and derive the effective areas or find those areas in a job book.
RE: Increase pressure in a compressor
And effective discharge area = discharge spool area ?
Thanks for your help.
RE: Increase pressure in a compressor
To estimate the axial thrust of overhung compressor is serious matter. going with such crude rule of thumb you are at risk that what you expect is one order of magnitude of actual.
please attach a description of compressor, stages, seal description, gear etc to let us help you in better way.
Regards
Wimple
RE: Increase pressure in a compressor
Here are the design specs :
Volume Flow Rate = 7060 Nm3/hr
Mass Flow Rate = 21655.4 Kg/hr
Suction Pressure = 0.15 Barg
Suction Temperature = 138 ◦C
Inlet Volume = 10620 m3/hr
Discharge Pressure = 0.593 Barg
Discharge Temperature = 208 ◦C
Polytropic Head = 2528 m
Brake Horsepower = 234 HP
Compressor Speed = 5813 RPM
Motor Speed = 1800 RPM
The compressor is supported with 2 tilting pad journal bearings and 1 double pivoted shoes thrust bearing.
Production guys want to increase suction pressure to be around 0.4 Barg. What other parameter will change due to suction pressure increment? And how that will effect the bearings ?
Please, let me know if more info are required.
Appreciate your help man.
RE: Increase pressure in a compressor
I suggest you to contact the manufacturer.
I hope the link will help:
h
Regards
RE: Increase pressure in a compressor
Do you mean by effective inlet area = impeller area - center bolt ?
And effective discharge area = discharge spool area ?
Regards,