2 replies to this topic

[YJ Choong]

To build an offshore acid gas (both CO2 and H2S) removal unit for natural gas to meet sales gas specifications, is a polymeric membrane or amine gas treating more feasible? Given the natural gas feed composition of H2S is 0.5 weight% and for CO2 is 10 weight%. Thank you!

[Amit J]

Choong,

There can be various points to be considered w.r.t. H2S removal system as described below....

 

A. Amine treatment option:

1. overall load for offshore platform will be more considering Gas Sweetening Unit(GSU) columns, pump, tanks, exchangers etc, their respective support & piping arrangement

2. there may be practical operational issues like frequent small leakages of amine which may pollute environment

3. periodical Amine make-up required

4. Being many rotary equipment, power requirement will rise for offshore platform. Also wear & tear issues demand periodic maintenance.

5. More Operator surveillance required.

 

B. Polymeric membrane option:

1. Comparatively static unit hence low wear & tear.

2. Periodical membrane replacement required which will incur significant cost for offshore location.

3. Because of periodical membrane replacement, secondary membrane unit required as standby to avoid production loss.

4. comparatively less load for offshore unit.

 

there could be some more commercial points to be considered before finalising option.

 

Some adsorption technology based options are also available. They will require additional post treatment.

 

All these options can give desired commercial H2S spec.

 

Please search another reference for CO2 removal option & its pros/cons.

 

Hope this helps.

[Technical Bard]

Would need information on scale.  For large gas flows, solvent based systems are more economical.  If you are at high pressure.  Since you don't really need selectivity, you could use DGA or MDEA if you are at high pressure.