During oil processing, heavier products are broken down by high temperatures into lighter products in cokers. This “cracking” process strips off lighter liquid hydrocarbon products such as naphtha and gas oils, leaving heavier coke behind. The challenge that CSIRO Minerals has been helping Syncrude resolve is how to best reduce coke deposits that build-up in their fluid coker stripper while maintaining or improving hydrocarbon stripping.

CSIRO is Australia's Commonwealth Scientific and Industrial Research Organisation, one of the world's largest and most diverse scientific global research organizations. Syncrude Canada Ltd. is the world's largest producer of crude oil from oil sands and the largest single source producer in Canada.

CSIRO Minerals is a long time user of CFX and in collaboration with the Clean Power from Lignite CRC developed the fluidized bed model in CFX-4. CFX, because of its robust multiphase capability and its ability to be extended into new application areas, is used extensively by CSIRO Minerals in undertaking complex CFD modeling of multiphase, combustion and reacting processes in the mineral processing, chemical and petrochemical industries.

By using CFD modeling to complement the physical modeling programs, scaling is eliminated and the actual dimensions and operating conditions are used. Furthermore CFX simulation provides much greater detail of the flows and forces in the stripper than can be obtained from physical models or from the plant. This is due to the difficulty in making measurements and visualizing the flow in complex multiphase systems.

Senior research associates at Syncrude, Dr Larry Hackman and Mr. Craig McKnight, explained that extensive cold flow modeling, but not CFD modeling, had previously been used to investigate the operation of the fluid bed coker stripper and the gas and solids behavior in the unit. Mr. McKnight said this project with CSIRO Minerals has resulted in detailed, high quality reports, which provide “a new understanding of the fluid coker stripper operation.” Dr Hackman indicated, “By using CFX to gain a better understanding, it is anticipated that design changes will be identified to improve stripping efficiency, reduce shed fouling and optimize stripper operation."

Another interesting aspect of this work is the distance between the two parties involved. When it is night in Edmonton, Alberta, Canada where Syncrude Research is located, CSIRO Minerals staff are hard at work in Australia performing analyses and posting results including pictures and animations, on the extranet. The next morning the group in Canada can view progress of the modeling work and provide feedback for a quick turnaround.

Using CFX, CSIRO is assisting Syncrude to determine how best to utilize their current plant to get maximum throughput and thus make the most of their capital investment.

Maintenance work on a coker unit at Syncrude's oil sands plant in Alberta, Canada.

Three-dimensional fluidized bed model of the Syncrude fluid coker "stripper". The model predicts the motion of bubbles (in purple) rising from injectors in the lower part of the bed and the complex flow behavior of coke particles.