7 replies to this topic

[zbrna]

Hello everyone,

 

so I have made a similar forum regarding to this, but basically I'm interning in an oil and gas company where they have given me a task/project to work on regarding their oversized gas compressor in the gas plant. They ask me if it is possibly to resize or change the compressor completely and what would the pros and cons be (would it be worth it). However,  I need to check if it is feasible in the first place with the current system they use before proceeding with any options.

 

I asked my supervisor about what factors to consider when it comes to checking the feasability. He said I have to check if it is feasible technical wise, financial wise, time wise, and operation wise. However, for technical, I would like some advice on what to check specifically. Shld i look at the PFD and P&ID? And if yes what should i look out for etc. etc.. What else?

 

thanks

[breizh]

Hi,

Yes, PFD and PID are the documents to understand prior to discuss with equipment suppliers.  You will find the equipment, the piping size and connections, the instruments.

Another document to read if the alarms and security matrix where you will find the consequences to actions from system (DCS,PLC) or Operators called interlocks.

Hazop study is also a document to read and understand.

Note You said there is a compressor decommissioned, this may be the right place to install a new and smaller compressor without interfering with the existing operation.

Prepare a specification sheet to submit to vendors, do your own calculation 

About cost and time, you should consider a reciprocating compressor as a base case (cost and delivery time) and compare with other technologies, centrifugal type and screw type.

Hope this is giving you some pointers.

Good luck

Breizh

Attached Files

•  litterature about centrifugal compressors.pdf   1.48MB   4 downloads
•  anti surge control.pdf   1.26MB   2 downloads
•  anti surge system.pdf   261.86KB   2 downloads
•  anti surge valve.pdf   5.44MB   2 downloads
•  compressor calculation shortcut.pdf   4.14MB   6 downloads
•  Controlling-Centrifugal-Compressors.pdf   651.33KB   2 downloads
•  simulation compresseur.pdf   1.78MB   6 downloads
•  settle out pressure in compressor loop.pdf   117.58KB   8 downloads

[Pilesar]

Compressor systems are quite expensive compared to most other regular equipment. When you talk to your expert compressor vendors, let them know you seek a reliable economic solution. They often provide much engineering work in anticipation of making a sale. They can help analyze whether revamp or replacement makes sense.

[zbrna]

Hi pilesar and breizh, 

 

Thank you for both your replies. I talked to one of the managers/higher ups and I believe that he told me that I shouldn't get too technical or that deep into it, especially as I do not have much time left and I am still a student. He just talked about how I should use the rule of thumb that if the flow rate or capacity is lowered, the energy consumption will generally lower. However, if that were the case then the power consumption of 2 mW would not be the same for the older flow at 40 mmscfd to the currrent one at 20 mmscfd. 

 

Since its a reciprocating compressor, what are the reasons this is? 

 

Thank you

[breizh]

Hi,

Consider this link to support :

Guide to Reciprocating Compressors - Atlas Copco Greece

 

Note  Are you sure the material compressed is the same, is the compression ratio the same?

You may have mechanical defect in your compressors, piston ring?

 

https://www.google.c...0L_MogA&csuir=1

Breizh

[zbrna]

Hi breizh,

 

Yes, the gas composition is the same, and the pressure (compression) ratio is approximately unchanged. The compressor is operating at a fixed speed. With it being at a fixed rpm, is this a possible reason as to why the energy consumption is still the same/relatively high?

[breizh]

Hi,

The capacity of the compressor is proportional to the speed * piston displacement .

If the speed is constant you may have an issue with the piston, as stated in a previous post .

Did you talk to the mechanical team at your place? 

Can you ring the representative of the manufacturer to get insights?

Do you observe similar behavior with all the compressors installed?

Breizh

[breizh]

Hi,

 

Microsoft PowerPoint - Speed control.ppt

 

Consider this power point to support your work.

Good luck

Breizh