H2S Liquid Scavenging system

[abbmct]

We are operating a H2S scavenging system export gas with liquid scavenger. we have a coalescer downstream of scavenger injection to separate the water/scavenger chemical with H2S. The coalescer is currently specified for 0.3 microns, which gets blocked and blown over. Can anyone share their experience in such a service at 45 barg pressure.

the inlet H2S level is 30 ppm
to be scavenged to 4 ppm downstream.

Thanks in Advance

 

[monaco8774]

All the scavenger chemicals work by reacting with the H2S to form an insoluble scale i.e. the byproduct is solids. Is there some reason why you have to filter all this byproduct out because at 0.3 micron filtration your going to go through filters at some rate. In fact you are filtering out everything down to bacteria, is it possible to relax that spec a bit?

 

[dcasto]

If you were sending me gas from your system that uses scavengers, I'd envoke the industry standard and FERC tarriff language about no dust, gum, rust, liquids, or other things that would be harmful to my pipeline. Scavengers are the worlds worst thing, if you are on the recieving end. Switch to process THAT REMOVES H2S and not one that hides it.

 

[abbmct]

Monaco: the spec. for filter was selected by the chemical supplier. We are looking at reducing the filter rating. I want to know your experience, if any, and what is the optimum rating. Downside, it will end in water and can have some impact on water treatment.

dcasto: At the current inlet level of H2S, other technologies are not suitable.

 

[dcasto]

Have you asked your gas buyer what they want?

If they have set the specifications then you have you cost benefit analysis complete, live with the specification or shut in the gas.

Amines system, sulfa treat, iron sponge, bacteria reduction process, crystasulf, all cost benefit driven....

 

[abbmct]

dcasto: We have done economical analysis. The buyer spec. 4 ppm H2S. For the current forecast, liquid scavenging is attractive for the next 4 years.

 

[dcasto]

Not knowing everything, but on most volumes at 400 ppm, accordrding to the Gas Research Institue the most cost effective are the ones I've mentioned. When you add in downtime and filter costs........................