Q & A > Question Details
Generally DMDS is used for hydrotreater catalyst sulfiding during the start up with new or regenerated catalyst. DBPS ( Di-t-butyle polysulfide) is known to be safer than DMDS due to its lower flash point than DMDS and other benefits as compared to DMDS. We like to know the prices of DBPS and DMDS. Which is costlier?
31/10/2008 A: Mukesh Patel, Reliance Industries Limited, mukesh.patel@ril.com
Other than cost, you must see the total requirement of the sulphiding agent and its sulphur content.
Typically, DMDS has higher sulphur content. However, price can be obtained from the suppliers.
08/09/2008 A: Randy Alexander, EURECAT, randy.alexander@eurecat.com
I don't know the cost of DBPS, but have heard that DMDS is now around $1.50 per pound.
Please keep in mind that the total cost of sulfiding can be much higher when you factor in the lost production time associated with in-situ sulfiding, the costs of treating the sour water formed during sulfiding, and the extra hydrogen consumed.
Pre-activation (often referred to as presulfiding) can be a more cost effective and hassle-free solution to in-situ sulfiding. Pre-activation offers these advantages over in-situ sulfiding:
- Load-and-Go reactor startups
- No exotherms from the sulfiding reaction
- No sour water make
- No additional hydrogen needed
- Negligible amounts of H2S will be circulating through the system during heat up, protecting sulfur-sensitive catalysts downstream such as reformer and isom catalysts
- No HS&E issues associated with handling sulfiding chemicals such as DMDS and DBPS.
- Upset conditions during startup will not have a negative affect on the pre-activated catalyst since all of the metal oxides have been converted to metal sulfides prior to loading the catalyst in the unit.
Eurecat's Totsucat process is the leading pre-activation technique available with experience covering over 250 hydrotreating units.