Mar-2010

Next generation BRIM catalysts

Five years following the launch of the first BRIM* technology, Haldor Topsoe recently commercialised the next generation BRIM catalysts made with improved production technology.

L Skyum Haldor Topsoe A/S
H Rasmussen Haldor Topsoe, Inc.

Article Summary

The latest member of the new generation is our ULSD CoMo catalyst, TK-578 BRIM, which is 10 -12°F more active than the leading industrial catalyst TK-576 BRIM. Below we will present data from an industrial ULSD hydrotreater where the high activity of TK-578 BRIM is utilised to increase the production capacity.

Improved metals dispersion
One of the key objectives with our research program was to increase the dispersion of the active sites on the carrier surface. By improving dispersion, the number of active sites for a given metal loading is increased, i.e. the intrinsic activity of the catalyst increases. This results in a higher activity for the catalyst, or alternatively, provides the possibility of maintaining the same activity with a lower metals loading on the catalyst. 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.

This research has 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 these same or higher activities all with a lower bulk density. Furthermore the catalyst strength is not affected. Using this improved dispersion technique we have recently commercialised seven new BRIM catalysts for services ranging from naphtha to VGO hydrotreatment, which are already in use in 55 hydrotreating units.

For maximum performance in ULSD operation at the low to medium pressure range, Haldor Topsoe has developed TK-578 BRIM. With the improved BRIM preparation technology we have increased the number of reaction sites relative to TK-576 BRIM, leading to an activity advantage of 10–12°F. Pilot plant testing and feedback from industrial operation have confirmed that TK-578 BRIM exhibits an outstanding stability equal to what our clients have come to expect of the market leading ULSD catalyst TK-576 BRIM.

Fig. 1 shows the results of the improved BRIM technology for the new TK-578 BRIM as 90% of the active metals on the catalyst are anchored on the alumina as a single or a double slab compared to 70% for TK-576 BRIM. This difference shows that the metals in the new catalyst are used more effectively while more brim sites and type II edge sites are generated leading to the higher activity.

The improved dispersion technique also enables Haldor Topsoe to produce CoMo slabs that on average are smaller than in the first generation BRIM catalysts. As can be seen in Figure 2, 81% of the CoMo slabs in TK-578 BRIM are 6 nanometer or less compared to only 73% for TK-576 BRIM. This means that for the same metal content TK-578 BRIM will contain more edge sites and consequently more type II sites compared to TK-576 BRIM, which again results in a higher HDS activity.

Operating experience with TK-578 BRIM. The following data compares the performance of TK-578 BRIM with TK-576 BRIM used in the same ULSD unit. The feed in both cycles consists of SR Diesel mixed with approx. 20–30% LCO (Table 1).

Table 2 shows the typical operating conditions.

The increased activity of TK-578 BRIM provides the refiner with the option to process a heavier feed, obtain a longer cycle length or increase feed rate. In this particular unit the refiner decided to increase the feed rate by 15% compared to the previous cycle with TK-576 BRIM. The normalised reactor temperature for the two runs are shown in Figure 3, and from this plot it is seen that the activity difference between TK-576 BRIM and TK-578 BRIM is approximately 10-12°F. The activity comparison is made from run day 30 forward, as the amount of LCO in the TK-576 BRIM cycle was less than typical in the first month of operation.

In conclusion, the use of our improved BRIM technology has enabled Haldor Topsoe to commercialise seven new products that exhibit equal or higher activities, while at the same time having significantly lower loading densities, resulting in fill cost advantages for our clients.

*BRIM is a trademark of Haldor Topsoe.