RAM Matrix

Building Block: RAM Matrix

Ultimate Coke Selective Bottoms Cracking Technology Summary

Grace Davison's RAM matrix is a proprietary reactive alumina matrix developed to provide improved bottoms cracking over competitive catalysts. Conventional wisdom suggests that as matrix surface area increases, bottoms yield decreases. However, not all surface area is equal. The activity or functionality of the surface area depends on (among others) surface acidity, acid site density, type of acid site (Lewis or Bronsted) and the site proximity to the proper diffusion channels. In addition, the size of the diffusion channels plays a significant role in bottoms upgrading. Therefore, it is not just surface area alone that determines bottoms yield; rather, it is the functionality of the matrix that is critical in determining bottoms upgrading capability.

In general, good bottoms upgrading requires relatively large pores to allow for proper diffusion of feed reactants to the active sites and products from the active sites. As shown in Figure 1, RAM matrix has higher pore volume than competitive catalysts in the large pore diameter range. This is the range which has proved to provide effective transport of large molecules to the active matrix sites, thereby enabling improved bottoms cracking.

Figure 1

However, pore size and pore size distribution can only partially explain the bottoms upgrading capability of a specific matrix. As mentioned above, matrix functionality is critical in determining bottoms upgrading capability. Although the individual parameters of matrix functionality are difficult to quantify, their combined effect is easily determined by pilot plant testing. For RAM matrix, Figure 2 clearly shows better bottoms cracking for RAM, despite having only moderate matrix surface area. The other catalysts in this testing represent a wide range of commercially available catalysts which are advertised for bottoms upgrading applications.

Figure 2

Bottoms upgrading is only part of the RAM matrix design. For a bottoms upgrading technology to be truly useful to a refiner, the matrix must upgrade bottoms to valuable liquid products, not just convert the bottoms to coke. Figure 3 shows the coke to bottoms relationship for the RAM matrix and a competitive catalyst. Not only did the catalyst containing RAM matrix cut bottoms better, but also it made less coke.

Figure 3

In addition, the RAM matrix provides excellent coke and gas selectivity in the presence of high nickel and vanadium levels. The RAM matrix was tested in the Davison Circulating Riser (DCR) pilot plant against two competitive bottoms cracking matrices. This testing was done on a heavy resid feed using 5000 ppm total Ni+V on the catalysts. Table 1 clearly shows the metals tolerance of RAM matrix in high metals applications. While all three matrices provided excellent bottoms cracking on the heavy resid feed, only the RAM matrix upgraded the bottoms selectively in the presence of metals. Coke and gas yield for the RAM matrix was significantly lower than the other two competitive matrices.

Table 1 RAM Matrix Shows Excellent Metal Tolerances compared to Competitor Matrices
5000 ppm Metals/CPS Heavy Resid Feed/DCR Testing

Matrix Type	RAM	Comp. A	Comp. B
Wt.% Conversion	72.0	72.0	72.0
C/O	4.6	4.0	4.9
H2	.66	.78	1.01
Total C1 + C2	3.6	3.4	4.1
LPG Olefins	10.7	9.5	10.3
Total LG	15.0	13.6	13.6
C5 + Gasoline	45.3	45.5	42.2
LCO	22.5	22.4	22.9
700 + Bottoms	5.5	5.6	5.1
Coke, Wt.% Feed	7.2	8.5	10.9

The excellent coke-to-bottoms relationship of the RAM matrix is shown in Figure 4. Compared to the other competitors' matrices, the RAM matrix offers both better bottoms cracking and improved coke selectivity.

Figure 4

The RAM matrix can be incorporated with Grace Davison's other zeolite and matrix building blocks to provide custom-tailored catalysts for a wide range of applications, particularly in applications requiring maximum bottoms upgrading.