Trace Sulphur Removal

[ivegotgas]

Our plant is a two train split flow (lean/semi lean)sour gas plant, running DEA. We currently run 4 HP contactors with one regen tower. There is a plan to bring on a significant amount of gas in the near future that is higher in trace sulphur compounds than anything we have dealt with in the past. (621ppmv COS, 358ppmv E. Mercaptan, 61 ppmv M. Mercaptan)

We already know that we are just barely making trace sulphur spec on our LPG product, and with the added sulphur species we will need to have some way of trating the LPG product.

We are currently investigating two methods, a package product from Merox, and one from Merichem. However the dollars involved for both systems are significant.

Does anyone have any suggestions or experience with treating liquid for trace sulphur removal (Or for efficient removal upstream)? At this point we are just brainstorming idea's outside the box so to speak.

 

[dcasto]

You could switch to a physical solvent or an hybrid like Sulfinol.

You could remove the mercaptains but the process keeps an equalibrium of H2S+CO2 to COS so you'd have to use a caustic process too.

Other things that are constraints to the type of process are percentage of high mole wt gases, pressure, temperature, CO2 and CO2 slip and amount of propane to be treated.

Generally, I'm with you on treating in the gas phase, liquid treating is not my favorite plant to operate. I've even gone so far as to take ethane off the top of the deethanizer and treated it as a gas, then condensed it in the product consensor.