Abstract. Heavy petroleum, residua, and bitumen provide challenges and opportunities for producers and refiners to identify attractive routes to marketable products. Coking and pyrolysis are commercial, non-catalytic, carbon rejection technologies for processing these materials. Higher yields of liquid product are achieved from hydrogen addition in fixed- or ebullating-bed technologies using conventional catalysts with active sites located within internal pore structure. Next generation MICROCAT* RC is a hydrogen-addition technology that uses a unique dispersed catalyst system in a bubble column reactor. The well-dispersed microcatalyst, present in ppm quantities, provides easily accessible catalytic sites which readily hydrogenate unstable free radical fragments and prevent coke formation. Moreover, because of its physical structure, microcatalyst suffers none of the pore plugging problems that plague conventional catalysts in heavy feed service. Further enhancements to microcatalyst systems should provide unique options for processing heavier feeds to higher quality products. * MICROCAT is a proprietary name for an ER&E-owned catalyst system.
Heavy crudes and tar sands bitumens comprise a huge untapped hydrocarbon resource. The province of Alberta, Canada alone has reserves in excess of 150 Gm3 (one trillion barrels) in the Athabasca, Cold Lake, and Peace River formations. In addition there are large heavy oil deposits in Mexico and Venezuela, including the Orinoco, Maya, Bachaquero, Panuco, Tamaulipas, and Tia Jana formations'.2.
These heavy crudes and bitumens have high viscosity which makes them difficult to produce and market.
Once produced, these crudes contain high levels of Sulfur, nitrogen, metals including vanadium and nickel. Many refineries cannot handle crudes and tar sands bitumens because of these contaminants, and because of the high resid content, around 50% or higher. These difficulties have inhibited the pace of development of these vast resources.
The key to unlocking the full potential of these resources will be the development and application of advanced, lower cost technologies, in mining, extraction, production, and in upgrading. While advances are being made in each of these areas this paper will focus on upgrading. The nature of these resources leads to three principle approaches: carbon rejection, hydrogen addition, or gasification.
Carbon rejection is typically accomplished by thermal cracking. Examples of developed thermal cracking technologies include Visbreaking, Delayed Coking, Fluid Coking, and FLEXICOKING3. Generally, Resid Cat Cracking options are not used for the heaviest bitumens or resids because of the high Conradson Carbon and the high metals.
Hydrogen addition options can be divided in