Compressor type for CO2

[22854]

I'm interested to know opinions on which compressor type (alternative , centrifugal, ecc.) is mostly used or reccomended from different points of view (operational, maintenance, initial cost, ec.) nowadays.-

Service is to compress low pressure (0,5/0,6 bar g) gaseous CO2 coming from MEA or MDEA purification unit up to 160 bar abs. to feed into an urea reactor.

Temp: 40 deg. C
Normal flow: 15500 Kg/hr
Max flow: 21500 Kg/hr

Power: approx. 2800 kW

Thanks for any advise

 

[zdas04]

22854,
You have a tough compression problem that everyone trying to do CO2 sequestration is facing. Basically you are looking at over 100 compression ratios which would be a really difficult 4 stage reciprocating compressor problem. The way I proposed this to my company is to go from 1,5 bara to 6 bara with a 2 stage eductor (power gas comes from a recycle line off the main compressor - probably from the first-stage discharge) and then 6 to 160 bara in a 3 stage recip (or more likely a multi-stage centrifugul to keep lube oil out of the reactor). You could do the first stage with a flooded screw, but product contamination is a real problem and the 2-stage eductor is really a better use of horsepower.

Everyone I've talked to that has tried to make this work with a single 4-stage recip, or a many-stage centrifugul has failed to meet any rational economic hurddle.

David

 

[PSucher]

As stated before, economics is a play.

My company can do this with a recip and that is typically used for this application (looks like acid gas injection). A centrifugal is not practical with the number of stages. IF you want to break it up into two machines, we may put a screw compressor on the first stage, but this is sedom done adn I cannot see and advantage in it.

We'll quote SS system to give long service life. CS construction has been used, but you will eventually eat away the corrosion allowance and need to replace components, so if you have a "short life" for project, CS may be the way to go. The trick isn't so much the build, but the operation of the unit. A purge gas will help increase life and lower corrosion of the system... There are may similar systems like this out there.

Give me an e-mail if you want a budget/firm quote and to discuss this application.

PSucher@ToromontProcess.com

Pat