
4 Apr 2007
Brenntag Oil & Gas offers a safe alternative for catalyst pre-sulphiding
Brenntag Oil & Gas Europe, one of the largest worldwide chemical distributors, offers through their partner, Lubrizol Corporation, the next generation catalyst sulphiding agent: SulfrZol® 54. With a flash point of 100 ºC, this product is much safer than traditional sulphiding agents, such as DMDS (di-methyl di-sulphide). Looking at current developments within the industry, which are forcing refineries to increase their levels of safety, Brenntag sees this as the best available product in the market. Th. M. Verleun, Business Manager at Brenntag Oil & Gas Europe, has assessed the various options in catalyst activation.
Catalyst change outs are a necessary evil in the oil refining industry. Next to the fact it is expensive and time consuming, it requires an extensive amount of high tech expertise and specialist safety measures onsite. According to Mr Verleun, catalyst sulphiding of new catalysts can be done much more safely.
Catalyst activation
Traditionally produced catalysts come in inactive / inert form, mostly a metal-oxide composition. To activate these catalysts, a defined quantity of sulphur is required on the catalyst surface. To keep the time and costs of the shutdown and change-out of catalysts as low as possible, this process needs to be carried out in a minimal amount of time, applying the highest degree of safety.
There are several ways to add sulphur to the catalyst surface. One of them is by starting the unit up with a sulphur rich feed stream. The highest risk will be that on start-up of a new catalyst with sulphur rich feed, the possible poisoning contaminants reach the catalyst surface more rapidly than the sulphur, and the efficiency is already reduced before the catalyst is taken in use. An alternative for many years has been the use of DMDS (di-methyl di-sulphide). There are several dangers associated with DMDS, which make it difficult to produce, transport, store and apply. Due to its extremely low flash point of 16 ºC, this product requires many precautions in the potentially high-risk environment of a refinery, especially at re-start time after a shutdown. Special containers and transport are required to transfer this material from the DMDS production location to the customer. Transportation needs to be at times of the day when there is low traffic pressure on the roads. Temporary storage of this product on the customer’s site requires special attention. People applying the product as well as people in the immediate surroundings of the application site require space suit like fire-protective clothing. Last but not least, this product has an extremely unpleasant odour, which can be a nuisance for the surrounding community as well as workers. DMDS producers are now incorporating additives to the product to mask the unpleasant odour, thus creating a so-called next generation DMDS. However, these additives are products, which are often, considered a serious hazard, some are even listed as such, so the problems associated with DMDS remain
SulfrZol® 54
The Lubrizol Corporation, a major producer of process additives, has carefully looked at the catalyst sulfiding hazards and obstacles that occur when applying DMDS. As a result they have developed a sulphur-rich product, which contains practically none of the above-mentioned hazardous properties, or negative aspects associated with DMDS. The product, branded SulfrZol® 54, is a polysulphide chemical, trapped in a bridge of t-butyl groups, designed specifically for in situ catalyst pre-sulphiding.
Thanks to its significantly higher flash point of 100ºC, SulfrZol® 54 is much safer to work with than DMDS. Consequently, no special measures are required for production, packaging, transportation and storage and no special clothing is necessary. SulfrZol® 54 also has no unpleasant odour. The normal diesel-like smell originates from the chemistry itself. No environmentally unfriendly odour masking agents are applied. A minor inconvenience one could mention is the lower sulphur content when compared to DMDS (~54% vs. ~65%), which results in a small extra dosage of SulfrZol® 54 being required to obtain the same amount of sulphur available for the catalyst.
Acceptance in the industry
Lubrizol and catalyst manufacturers worldwide have cooperated in the development and testing of SulfrZol® 54 as a catalyst sulfiding agent, and as a possible alternative to DMDS. Based on those tests, all catalyst producers have concluded that SulfrZol® 54 is an acceptable and efficient alternative. Although for some exceptional applications the product has not yet been tested and approved by all catalyst manufacturers, theoretically there is no limitation to the use of SulfrZol® 54 for much safer and user-friendly catalyst sulfiding processes. The product has already been successfully applied for catalyst sulfiding by many major European refineries such as Exxon, Tamoil, Shell (in several countries), Czech Refinery, Nynas, Repsol and several more. (A reference list is available on request). Catalyst producers / developers as well as operators / managers of a (sulphur activated) catalyst bed who have used SulfrZol® 54 have reported positive feedback on its ease of use.
Brenntag services
Brenntag Oil & Gas is the official distributor on behalf of the Lubrizol Corporation for SulfrZol® 54, virtually worldwide. Brenntag can also offer catalyst sulphiding injection services onsite on a turnkey basis, if requested by the client. In fact, since the level of risks accompanied with the use of SulfrZol® 54 is so low, the refinery staff or catalyst manufacturers staff can inject the SulfrZol® 54 with a regular high-pressure pump themselves. This, in contradiction to DMDS, which requires DMDS producers to always provide the ‘’safety-service’’, as described above, with the product.
Other applications or special packaging
SulfrZol® 54 can also be applied as an anti-coking agent in (Ethylene) crackers, by continuous injection to avoid deposit formation. Unlike DMDS, which needs to be placed under nitrogen pressure in closed IBC containers to reduce its smell and to reduce the low flashpoint dangers, SulfrZol® 54 can be stored onsite in regular containers and does not need to be in a closed system, which is again a safety advantage.
Conclusion
In today’s environment, safety is becoming more and more important. With the new development of SulfrZol® 54 from The Lubrizol Corporation for catalyst activation processes, DMDS is no longer the sulfiding agent of choice to refineries. Safety managers and operators at refineries, who take safety as a key element of their daily job, need to consider the alternatives for catalyst sulphiding processes. SulfrZol® 54, which can be used for the same applications and has an equal performance level as DMDS, is a preferred alternative as it will lead to increased safety at refinery plants.
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Notes for editors
About Brenntag
Brenntag Oil & Gas is a member of the Brenntag Group. In 2005, Brenntag succeeded again in underpinning its position as a globally leading chemical distributor. The company recorded external sales of EUR 5.3 billion (US$ 6.6 billion). Brenntag operates in more than 300 locations with 9,200 people in 50 countries. Underlying the company’s strong position in world markets, Brenntag is committed to providing value to its customers and suppliers through superior supply chain logistics, single sourcing and value-added-services. To its suppliers and customers alike, Brenntag offers, both in Europe and the Americas, an unrivalled, extensive and state-of-the-art distribution network for industrial and specialty chemicals.
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