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Centrifugal compressor performance prediction program

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rotw

Mechanical
May 25, 2013
1,143
Hello,

I would be grateful if I could gather some opinions with respect to the following:

I refer to centrifugal type of compressors / multi-stage ; as you know, when such type of equipment is involved, it is custom that the OEM / compressor manufacturer provides the performance data to the customer (in line with the request for proposal). The reliance on VENDOR DATA is generally quite significant (from concept/feasibility, front end engineering design to real execution/construction projects). The thing is that Vendor(s) is/are not always activated on the project of consideration and even when they are, there always is a certain lead time involved between the inquiry and the proposal ; my experience is that typical lead time is anywehere between a week (when fast tracked or the job is straighforward) to a couple of weeks.

Anyway for simple cases, I suppose that it is quite possible to make a rough estimate of equipment expected performance using some pre-selection spreadsheets (e.g. GPSA-based formula to estimate power, efficiency etc.) that would allow to "by-pass" the OEM and workaround lead time and short/long cycle issues. Problem is that when specifications are a bit more complicated, any rough selection quickly falls short. Probably main reason for this is that centrifugal compressors have limited flexibility to accomodate offdesign operation and in-depth review is required when there are multiple cases that would stretch the performance envelop.

This brings me to the point of the topic: do you guys see any advantadge if you would be provided with a centrifugal compressor tool that would improves upon a preliminary selection tool ? To quantify the difference: say the error is ~5% to 10% or more for simple spreadsheet, it would be around 1 to 2% error for sophisticated tool. Also the later would estimate the performance envelop/ map.

Reason for my query is that I am working on a software for compressor selection and I am trying to gauge its worth before my next step which is to do some beta-testing. I am sure that many of you have interacted with centrifugal compressors in a way or another, as operators, process engineers, machinery experts, maintenance engineers, etc. (whatever new units, revamp, upgrade or retrofit project it is, etc.). Your experience and feedback in this regard would be very valuable to me.

Thanks

 
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I have not come across such performance map generator yet.

So far these software are OEM proprietary. The application engineers and design engineers have access to it.
 
back around 2000, i would just contact the centrifugal compressor Rep application engineer and get a response easily within the day. after much discussion, i obtained a sizing program to give initial performance data (i.e. efficiency, head, flow, etc) based on inlet/outlet data and gas composition. another gas compressor mfg, undergone an acquisition since, provided an excel workbook for their initial sizing and it generated curves. for these 2 vendors, the preliminary/initial results were not that far off from the proposed sizing. better input data provides better results.
for off-design conditions, i use the original OEM curve with the understanding that there are no geometric changes to the compressor. from my feeble memory, there are 2+ papers written by an elliott engineer on evaluating/rerating centrifugal compressors for off design conditions based on existing curves. i've used these papers along with OEM data. you may want to search/investigate those papers or contact elliott.
i'm thinking just how much your efforts expended in what you are doing versus just contacting the compressor rep application engineer. never go through the sales group as you will wait forever.
the process from initial design to proposal/purchase is iterative as the process guys can make changes to the process design to best fit the compressor & driver.
hope this helps and good luck.
 
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