Start-up air in reciprocant compressor

[jeap]

Hi All!

Any one know what is a typical flowrate for start-up air in a reciprocant compressor for natural gas?

and what this air is used for?

Thanks in advance.

 

[dcasto]

I'll make a leap of faith here. The air is used to drive an air motor that turns the engine to start the engine. On older intergal compressor engine sets the air was injected into the power cylinders with the fuel shut off in a sequencial manner to again get the engin turning so it would start.

 

[Montemayor]

Good leap dcasto.

It could also be the start-up air requirement for a diesel engine driving the field-located, natural gas compressor.

As is becoming (or has become) the usual case the Original Poster (OP) doesn't communicate well or doesn't know how to furnish basic data. And because of this failure, we all have to guess/leap - at best.

 

[sms]

I am not sure we can say much about flow rate without know compressor size supply pressure, line configuration, etc.



-The future's so bright I gotta wear shades!

 

[dtn6770]

Assuming the question deals with the air (gas) needed to start the engine driving the compressor, the answer is, "it depends."

The air starting requirments will depend on the specific engine, the specific starter, supply air pressure, and the required cranking time. The cranking time depends on the engine model, engine condition, ambient air temperature (a variable), fuel type, engine oil viscosity, and design cranking speed. Hot starts will take less air than cold starts. If there's a prelube system, is it air driven as well?

I'll toss out 40 to 80 cubic feet as a starting place but open a dialog with the engine/starter manufacturer(s).

 

[jeap]

I really appreciate your help.

In fact your comments (preachings) took me to find the answer I was looking for. Your "leaps of faith" were really close if "40 to 80 cubic feet" means scfm.

Although I needed a "order of magnitude" value to verify de diameter of an air line. "Order of magnitude" to this specific case is 40-80. Thanks dtn6770.

I contacted the starter manufacturer and found the air consumption for the service (50 scfm at 150 psig).

Thanks again