Posted in | Pollution

New Catalysts Recovery Project for Sulfur Emission Reduction in Refineries

It has three self-sustained lines of research: reactivation of titanium oxide catalyst, biological treatment for sulfur disposal and evaluation of new alternative SuperClaus catalyst formulations.

Wanting to improve the catalysts used in sulfur recovery plants of Pemex Gas and Basic Petrochemicals (PGPB; Pemex is an oiling Mexican company), the Mexican Oil Institute (IMP) developed a project of titanium dioxide reactivation implemented in the Claus process.

PhD Roberto Garcia, project manager of the Research Directorate of the IMP explains that the Claus and Superclaus processes reduces sulfur emissions generated by a refinery, through materials called catalysts, which adsorb the chemical element.

"Crude oil contains sulfur and during the transformation processes of hydrocarbon it is removed; however, the waste needs to be treated with an active catalyst in order to avoid emissions that pollute and can produce acid rain," says the IMP researcher.

For this titanium oxide catalysts that remove sulfur are used, but over the years they are deactivated and reactivation or replacement is necessary.

The research focuses on the catalytic recovery in the Super Claus process. Dr. Cruz is also analyzing which chemicals deactivate the catalyst and looks for technological alternatives to replace or reuse the wasted material.

The doctor in chemical engineering requires the innovation to be beneficial for Pemex because it can cut costs invested in a new catalyst, which is purchased at an average of $ 10k per tonne.

The project was divided into three lines of research that are self-sustaining: reactivation of the titanium oxide catalyst spent during physicochemical processes, treatment for disposal by biotechnological methods and evaluation of new alternative catalyst formulas that led to several patents.

In the first line of reactivation research, titanium oxide catalyst property was recovered by up to 20 percent, avoiding the purchase of a new one.

Roberto García de León detailed that in the second line of research bacteria from sulfur water areas were analyzed and modified to achieve a higher resistance to the chemical element. Furthermore, DNA sequencing was performed for the taxonomic identification of the strain.

The biological treatment system proved capable of removing between 91 and hundred percent of the sulfur in the catalyst over a period of 21 to 35 days.

Registration and deposit of two bacterial cultures in the German Microbial Culture Collection was also achieved, which yielded the patent of the project and made it available for the Mexican and international companies.

For the third line of this investigation, the best catalyst systems for the selective oxidation if the sulfur were selected, where three groups were defined: titanium nanotubes, catalytic systems of titanium oxide and mesoporous stabilized materials stabilized.

These systems were obtained from the mesoporous material modified with iron, and a series of catalysts from silicon oxide were found. "In this research we removed the chromium in oxidation state 6, which is not friendly to the environment because it can be carcinogenic," said Roberto Garcia.

During the two years that the project lasted, nine thesis in chemical engineering and biotechnology were obtained, as well as a Master of Science, two doctoral degrees, a postdoctoral residence and five patent applications were achieved.

The project also involved the collaboration of the University of San Luis Potosi and of the Applied Research Center for Advanced Science and Technology (CICATA) of the National Polytechnic Institute of Queretaro. Its financing came from the Hydrocarbon Conacyt-Sener fund from Mexico.


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