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[Beergson]

Dear Cheresources Forum Members,

 

Do you know any standard where I can find any guidelines for maximum lenght of low pressure (20-30 kPaG) compressor suction pipelines length?

 

We are working on oxygen production unit (VSA) project and there is a concept to use existing compressors for oxygen product compress but suction pipeline has to be ca 450 m lenght.

 

I know the rule that pumps suction shall be as short as possible (especially for boiling fluid), but I've never heard the same rule regarding compressors suction. 

 

Any ideas?

 

Any help will be appreciated

Edited by Beergson, 26 August 2015 - 02:16 AM.

[ankur2061]

Beergson,

 

There are no specific rules for length of suction piping. But the following general guidelines related to suction piping will ensure that the compressor system performs satisfactorily

 

1.  Traces of liquid in the gas being compressed require a properly designed suction scrubber and routing the piping to the suction flange in such a manner that there are no loops and low points in the suction piping where there is a possibility to accumulate liquid. Liquid slugs can result in serious damage to compressor internals.

 

2. Obviously for a desired suction pressure at the suction flange of the compressor, the pressure drop in the suction line needs to be kept within the limits of the desired or optimum suction pressure for a given gas. This may require keeping the suction pipe length short or increasing the suction line size or both. This would require a pressure drop study by the process engineer to determine the acceptable pipe length and the pipe size.

 

3. In case loops and low points in the suction line become unavoidable due to layout constraints, then strategically located low-point drains with automatic or manual drain valves should be provided to prevent liquid entering the compressor casing and causing damage.

 

4. In case the gas being compressed is bone dry. points 1 & 3 do not apply and the suction pipe length is constrained only by the line pressure drop.

 

Hope this helps.

 

Regards,

Ankur.

 

PS: Line pressure drops in short gas lines are much lower than for liquids and sometimes conveniently ignored.

Edited by ankur2061, 26 August 2015 - 07:02 AM.