The effectiveness of Five commercial hydrotreating catalysts were evaluated using a partially upgraded synthetic crude distillate feedstock. The hydrotreating catalysts are typical of those currently in use by commercial refiners. Each catalyst was tested at a variety of operating conditions to define the performance. The selected conditions are similar to those utilized In commercial units but the data are not directly applicable to commercial operations because small-scale laboratory equipment was used.
The feedstock was heavy coker gas all derived from the delayed coking of Athabasca bitumen. It has high sulphur, nitrogen and aromatic content making it a more than suitable test feedstock.
Denitrogenation, desulphurization. hydrogen consumption and yield patterns were assessed for each catalyst. All the catalysts produced an acceptable, hash quality liquid product. The results indicated significant differences and which catalyst was clearly superior.
The project was sponsored by CANMET to develop an independent Canadian capability in screening catalysts and synthetic feedstocks for hydrotreating applications. This was to be accomplished by completing a number of specific project objectives, including:
Conduct hydrotreatinq experiments on synthetic crude distillates and evaluate the applicability of conventional hydrotreating technology to the refining of the new generation of feedstocks such as those derived from heavy oils and enhanced oil recovery (EOR) crudes.
Develop test procedures to secure reliable information and establish techniques For predicting performance in commercial hydrotreating units.
Obtain data, such as distillate quality, yield. etc., and qualitatively assess the ability to meet further downstream refining (e.g. catalytic cracking, performing, visbreakinq, etc.).
Develop Canadian expertise in the areas of hydrotreating of distillates derived from Canadian crude feedstocks.
Encourage the evolution of a distillate hydrotreating testing centre, readi1y accessible to potential customers from all sectors, public, private and universities.
Conventional high quality crude production is declining in Canada and synthetic crude (from upgrading tar sands bitumen and other heavy feedstocks) production is increasing. Production expansion at Sync rude (Fort McMurray) and the completion of the Co-op Upgrader (Regina) will significantly Increase synthetlc crude production in Canada. If further eY-penslon of Syncrude and the Husky upgrader proceed, synthetic crude production will increase even more in the future.
Synthetic crudes differ significantly from naturally occurring crudes. Such characteristics as higher sulphur, nitrogen and aromatic levels make them more difficult to process with existing refining technology. [t is essential to test conventional hydrotreating technology to establish its applicability, and modify or develop experimental techniques to correlate the performance of synthetic distillates in conventional hydrotreaters.
A laboratory-scale continuous hydroprocessing unit capable of operation to 20.7 MPa (3000 psi) and 500 °C was used for the catalyst evaluation. A simplified schematic of the unit is provided in Figure 1. The unit has a fixed catalyst bed with a reactant down Flow configuration. The catalyst volume is 30 cm3. The feed pump is a positive displacement, adjustable stroke piston pump. Hydrogen Flow is controlled by a high accuracy mass flow controller.