15 replies to this topic

[FacilitiesEng]

Dear All

Currently, our offshore platform is producing about 16 mmscfd of gas. However, the CO2 contents is deadly high i.e up to 65% and we need to flare it our entirely (also require huge amount of propane to ensure the flare keep flaring).

Suggestion has been made to install the mini CO2 removal at our platform so that we can use our produced gas as a fuel gas, artificial lift or as a blanket gas.

Do any of you have experience in CO2 removal technology? How small it can be built?How much cost should I consider? and the delivery period.

Appreciate your assistance on this.

Attached is our Produced Gas Composition

Cheers

Attached Files

•  Gas_Composition.pdf   834.23KB   120 downloads

[gvdlans]

Why don't you contact one or more suppliers of CO2 removal units? My guess is that you need either an Amine Unit or a Membrane Unit.

I found the following hit with Google:

http://www.newpointg...hure_Letter.pdf

[JoeWong]

The LHV for your gas is more than 300 Btu/scf, should be self combustible without additinal fuel injection. Why kind of flare tip you have (sonic, pipeflare, tulip, etc) ?

I am interested to know which field you are operating now. PM3 area, Natuna, Bongkot, Arthit, etc ?

You mentioned that the supplementary gas is required for good flare combustion. Now you suggest to install a CO2 removal to recover some HC so that can be used for fuel gas, blanketing, etc. What will you do with the CO2 rich with HC stream ? Are you intended to bring the HC in CO2 level down to environmental permissible level and vent directly to ATM ?

CO2 can be removed by amine, activated amine, physical solvent, membrane, etc. Oridnary solvent is open art. Some activated amine may have licensor i.e BASF, SGS, etc. Membrane licensor are NATCO, UOP, etc.

For membrane , it is in module or catridge form. It can goes very small to very big capacity.

[irprocess]

The correct method for removing CO2 is dependant on CO2 concentration. At low CO2 concentrations mole sieves from ZeoChem, UOP and Grace are good places to start. At CO2 concentrations over 1%, then amines or other solvent/reaction based systems are best. If concentrations are over 20%, then UOP and others have membranes.

If you need more information,I would appreciate to send you via email.

Regards

[Zauberberg]

I'm not sure what levels of selectivity one can expect if membrane system is used, with regard to CO2/Hydrocarbon ratio. This can be important factor if you are considering venting CO2-rich stream to atmosphere, and hydrocarbon content could limit your potential for venting. On the other hand, big advantage of membrane units is small footprint space which makes them being good candidates for offshore facilities. Operating pressure is an important factor for evaluating feasibility and efficiency of membrane system.

As suggested above, it's recommended to contact different vendors - after defining your constraints regarding atmospheric emissions and fuel gas quality. I suppose there are no other contaminants in the gas stream, such are: H2S, COS, RSH - in such case you will need to find the best way for distributing these components between the acid gas and treated gas streams, which would in return define the technology you have to use in your platform.

[JoeWong]

There are many type of membrane with different yield and selectivity for CO2 separation... Nevertheless, in case of permeate gas venting directly to atmospheric and residue gas as product, both stream specification shall be meet. This is very difficult to operate...

Apart from pressure, differential pressure across membrane, feed temperature also affecting the performance of membrane.

Talk to vendor to get more information...

[djack77494]

There are other technologies that might be applicable. For example there is a process known as the Benfield Process that uses a solution of (mainly) hot potassium carbonate to absorb CO2 from process gases. There are others based on physical solvents and probably ones I haven't heard of as well. A lot depends on initial and desired final concentrations and purity requirements for the off-gases. The answer to determine the "best" technology is research (on your part).

[JLMONTREAL]

Why don't you contact one or more suppliers of CO2 removal units? My guess is that you need either an Amine Unit or a Membrane Unit.

I found the following hit with Google:

http://www.newpointg...hure_Letter.pdf

One more reference is http://www.cansolv.c...nt/CO2-Enew.pdf

Review it to see if you need a contact in charge.

[Erwin APRIANDI]

Hi...

There'are alot of commercial process that available in order to sweeten the gas so it is suitable for use.

The major process are:
1. Amine Absorbtion
2. Membrane
3. Redoks Process
4. Solid Pack Adsorbtion

For your gas compositon I assume that Membrane and Amine system are suitable, I've been involve in a FEED study which evaluate all the technology available for sweetening unit.

Below is some recommended technology supplier that you can contact
1. Dow,
2. Shell Global Solutions,
3. Natco,
4. UOP,
5. MTR (Membrane Technology Reasearch)
6. Crystatech,
7. Merichem - Lo-Cat Technology.

For the address I this you will not have problem finding it from the web, since my contact person basis is for the south east asia location.

Best Regards...,

[Zauberberg]

Membranes are not recommended for deep CO2 removal in any case. If you are targetting ppm's in treated gas, you would need multiple/cascade units. This is not en economic solution.

Do the research on your side, as suggested by Doug. You know what are your constraints, and after initial screening you'll be able to narrow down the list of potential technologies/setups.

Good luck,

[JoeWong]

Agreed.

Common combination is membrane for bulk removal follow by amine for ppm target...

[Dtan76]

Hi

For bulk CO2 removal and high CO2 concentration (20%, 40% or even 65%), membrane Unit will be good choice and every cost effective compare to Amine technology.

Rule of thumb here:
Membrane CAPEX = 1/3 of AMINE CAPEX
Membrane OPEX = 1/3 of AMINES OPEX

For membrane unit, you can contact local UOP representative. (I think they just setup up office in Malaysia)

Regards

Attached Files

•  KPC_CO2_Membrane_System.pdf   655.58KB   84 downloads

[Dtan76]

Here another link regarding bulk CO2 removal using membrane:

http://www.uop.com/o...emvbyMembrn.pdf

Cheers

[Andrei]

Gentlemen,

Less than one year ago I was facing the same dilemma. I would like to share a few things with you.
1. The CO2 composition, average 41% mol (I hope that average includes each stream flow, and is not a simple arithmetic composition average) is just at the boundary between an amine sweetening application, and a membrane separation. What will set them apart will be the pressure of the stream.
2. There is a fairly high content of heavy components, especially benzene and toluene that will have to be removed if a membrane system is to be used. Otherwise the membranes will be quickly degraded. This will be done with some kind of refrigeration, translated in more equipment and more energy consumption.
3. Amine unit is a relatively simple stuff, but with high energy demand.
4. In the membrane case, to improve the selectivity usually a recycle is required, so extra equipment and energy consumption.
5. Most probably, as Joe suggested, a combination of membrane + amine separation will be the most cost/quality effective solution. But a great deal of optimization is required.
The bottom line is: you can ask advice here, but the space available will never be enough to cover all the aspect of the matter.
If you really want to pursue the matter I strongly encourage you to contact a suitable consultant to get an answer whether it is economical to separate CO2 or not, and what is the most effective method of separation.
And you should be prepared to find out that will cost you more to separate CO2 than just flare it using some fuel. I am giving about 75% chance to this statement to be true.
And almost sure you cannot do any change there without the platform designer.

Good luck

[riven]

And you should be prepared to find out that will cost you more to separate CO2 than just flare it using some fuel. I am giving about 75% chance to this statement to be true.
And almost sure you cannot do any change there without the platform designer.

Good luck

This is definately the correct answer in this case for current technology. Removing CO2 using amines at high concs is not economically viable.

Nor are membranes. Currently the problem is not selectivity but low permeability. The permeabilities are so low that not only are the units too large to be cheap but they are difficult to fit on a platform. This problem is further confounded by low concentrations of heavies which reduce the permeabilities even more. Long term stability (3 years +) should not be an issue.

[mido]

i suggest to remove co2 by membrane .
its good method low cost,low weight,low labors requirement