Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Loss of sulphur atom reduces activity of catalyst

17.03.2005


Chemical catalysts used to produce clean fuels gradually become less active. Dutch researcher Bas Vogelaar believes that the loss of sulphur atoms might be an important cause of this. He investigated hydroprocessing catalysts which remove sulphur compounds from petrol and diesel.



Crude oil contains sulphur compounds which form sulphur oxides during the combustion process. These sulphur oxides are an important source of acid rain.

Hydroprocessing catalysts are used in oil refineries to remove these sulphur compounds in order to produce clean fuels. After two years of use, the hydroprocessing catalysts have lost so much of their activity that they need to be replaced. This is an intensive and expensive operation. Vogelaar established the most important causes for the deactivation of hydroprocessing catalysts in order to increase the lifetime of these.


A hydroprocessing catalyst consists of a carrier of aluminium oxide, to which various active metals are added. A so-called active phase is created on the surface of the catalyst. The chemical reactions during which the sulphur is removed take place here. The active phase consists of a combination of molybdenum, sulphur and nickel or cobalt.

Self-cleaning

Small graphite-like particles accumulating on the hydroprocessing catalysts are one of the causes of the decrease in activity. Vogelaar discovered that this ’coke’ mainly precipitates on the carrier. He believes that the active phase has a ’self-cleaning’ effect, which can counteract the precipitation of coke. The researcher discovered that under model conditions, the activity of the catalysts mainly decreases due to the loss of sulphur from the catalyst. This process might also play a role in the deactivation of these catalysts during the production of clean fuels.

Desulphurisation

Catalysts can convert sulphur compounds in two ways. The sulphur atom is directly removed from the compound or a chemical reaction (hydrogenation) takes place after which the atom is removed. The results of Vogelaar refute the generally accepted theory that for both mechanisms a sulphur atom must first of all be removed from the active phase. For the direct removal of sulphur a so-called ’vacant position’ is indeed necessary. The hydrogenation step however takes place on sulphur atoms at the edge of the active phase and not on the ’vacant positions’. Vogelaar has used these results to produce a detailed model for the structure of the active phase. He has also developed a model which describes the desulphurisation reaction mechanism.

Dr Bas Vogelaar | alfa
Further information:
http://www.nwo.nl/nwohome.nsf/pages/NWOP_69LLET_Eng

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

12th COMPAMED Spring Convention: Innovative manufacturing processes of modern implants

28.05.2018 | Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

 
Latest News

International Workshop Sees Central Role for Solar in Transforming the World Energy Economy

28.05.2018 | Seminars Workshops

Cognitive Power Electronics 4.0 is gaining momentum

28.05.2018 | Trade Fair News

Organic light-emitting diodes become brighter and more durable

28.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>