Hydrorefining of Shale Oil (Part 4) Pretreatment for Arsenic Removal

Abstract

With the objective of selecting suitable reaction conditions and catalysts for a guard reactor used in shale oil hydrorefining for arsenic removal, two kinds of Mo-Ni-Al2O3 catalysts and γ-alumina have been evaluated. It was confirmed that most of the arsenic present in shale oil is removed under such relatively mild reaction conditions as 300°C and 2.0 LHSV, using conventional Mo-Ni catalysts for petroleum hydrorefining. All arsenic removed from the shale oil deposited on the catalyst, and no arsenic was detected in the effluent gas from the reactor. The arsenic deposition profiles in the catalyst pellets vary depending on the reactivity and diffusibility of arsenic compounds. Suitable catalysts for the upper layer in the guard reactor should be provided with medium initial activity for arsenic removal, with larger pore diameter, and with the shape of pellets with a greater ratio of external surface area to volume. The metal contents of the catalyst should be increased commensurate with the expected amount of arsenic deposition. © 1993, The Japan Petroleum Institute. All rights reserved.