Next-generation BRIM catalyst technology
The need for high-activity hydroprocessing catalysts continues, with US, European and Asian refiners already supplying their markets with ultra-low-sulphur diesel containing less than 15 wtppm sulphur. The trend for low-sulphur fuels is spreading step by step throughout the rest of the world.
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In response to the need for high-activity hydrotreating catalysts, Topsøe introduced in 2003 the first catalyst based on a new production technique that we called BRIM technology. Topsøe’s BRIM catalysts were quickly accepted by the industry and are today widely considered to be the leading technology.
Now, six years after the introduction of BRIM, we are pleased to announce the introduction of the next-generation BRIM catalysts made with an improved production technology. In this paper, we will show how these new catalysts can improve the performance in hydrotreaters, and demonstrate how the extra activity can improve the economics of hydrotreating for the refiner.
Next-generation BRIM catalysts
Following the launch of the first BRIM technology in 2003, Topsøe introduced at the end of 2008 the next-generation BRIM catalysts made with improved production technology.
One of the focal points in our research into improved hydroprocessing catalysts at Topsøe is to increase the dispersion of the active species on the carrier surface. By improving dispersion, it is possible to increase the number of active sites for a given metal loading, resulting in more intrinsic activity. This leads to a higher activity for the catalyst or, alternatively, gives the possibility of maintaining activity while loading less active material into the reactor. Having less active material could raise concerns about catalyst stability, but the number of active sites per reactor volume is unchanged, and therefore the ratio of active sites to coke precursors is unchanged, and the rate of deactivation is unaffected. Another way of increasing the activity is to put more metals into the catalyst. But the full effect of adding more metals is not achieved unless the metals can be well dispersed. So improving dispersion can result in a number of benefits.
This research has now resulted in the development of our improved production technology. The advantage of this improved technology is that we achieve a better dispersion of the active species and at the same time increase the porosity of the catalyst. This results in catalysts with same or higher activities at lower filling densities. And, very importantly, catalyst strength is not affected.
The new technology has potential for all of Topsøe’s current catalysts, and as per the date of writing we have commercialised five new catalysts.
Next-generation BRIM catalysts for VGO service
With this new and improved BRIM technology, we have launched a number of new catalysts for FCC and hydrocracking pretreatment. Table 1 shows the data of the original and the next- generation pretreatment catalysts.
In HCR pretreatment, the new NiMo catalyst, TK-607 BRIM, is offered with higher activity than the previous generation, TK-605 BRIM, and due to the improved metal dispersion it is manufactured with a lower filling density.
The successors to the well-established TK-558 BRIM and TK-559 BRIM in FCC pretreatment service are designated TK-560 BRIM and TK-561 BRIM respectively, and will in many cases enable refiners to meet the future specifications for ultra-low-sulphur gasoline without post-treatment. Both TK-560 BRIM and TK-561 BRIM are designed and manufactured to have the same activity as previous-generation Topsøe CoMo and NiMo BRIM catalysts, but with a lower fill cost due to a lower filling density.
For refiners operating FCC pretreaters for short cycles due to low product sulphur requirements, TK-562 BRIM is the optimal catalyst. This catalyst is manufactured to give maximum activity while maintaining the excellent stability the industry have experienced with TK-558 BRIM.
High activity of BRIM catalysts in FCC pretreatment service is also of great importance for HDN and saturation of aromatic compounds, which positively affects the yield and quality of the gasoline produced in the FCCU. With tighter fuel specifications, the increased activity of the BRIM catalysts is thus primarily utilised to achieve better product properties. Despite operating the BRIM catalysts at higher severity in FCC pretreatment service, their performance has shown equal or better stability than previous catalyst generations.
Traditionally, NiMo catalysts have been looked upon as having a higher HDN activity and CoMo catalyst a higher HDS activity for FCC pretreatment service. A high HDN activity is desirable for the removal of nitrogen compounds and, in particular, basic nitrogen compounds from the FCC feed. These compounds would otherwise adversely affect the yield and quality of the gasoline produced in the FCCU.
The optimal choice between NiMo (TK-561 BRIM) and/or CoMo (TK-560 BRIM and TK-562 BRIM) pretreatment catalysts is dictated by the unit pressure, feed nitrogen, operating temperature and desired product properties. The CoMo-based TK-560 BRIM and TK-562 BRIM types will provide the best performance in low-to-moderate pressure units. Due to our BRIM technology, the Topsoe CoMo BRIM catalysts exhibit an HDN activity that is as high or higher than a NiMo catalyst at these moderate pressures and much higher HDN activities compared to conventional Type I or Type II CoMo catalysts. TK-562 BRIM is the catalyst of choice for the refiner who wishes to produce low-sulphur FCC products without changing yields of gasoline or other high-value products.
In high pressure FCC pretreatment units and in cases where nitrogen is the main concern due to the performance of the FCCU, the preferred choice will be TK-561 BRIM due to its higher HDN activity at these conditions.
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