A New Approach to Lowering Total Sulfur in LPG

Technology innovation at Merichem Company has provided a new approach to lower the total sulfur in the LPG product stream. This new development is driven by state-of-the-art technology that achieves product sulfur specification of less than 3 ppmw. 

Recent changes in fuel standards complying with EPA Tier 3 have caused many refiners to address their compliance methodology for fuel sulfur levels. One area that is often missed is the advancements available in caustic treating. Offering a lower CAPEX and OPEX, with no reduction in octane, caustic treating continues to find a place in the modern refinery process portfolio. 

Many caustic treating systems can achieve less than 30 ppm total sulfur in LPG blends by removing acidic sulfur species: hydrogen sulfide, carbonyl sulfide and light mercaptans. What is not well known is that this same technology can reduce extractable sulfur to less than 3 ppmw (not counting non-acidic, inert species) with the application of new developments in process layout and catalysts. 

This paper discusses the operation of such a unit at a major U.S. Padd 2 refinery in the United States.