International Union of Pure and Applied Chemistry

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Panel I - Innovative Process and its modalities
Paper N1.2 - Use of X-ray Imaging in the Innovative Development of BP's LEAP Technology
Merion Evans, Hull Research and Technology Center BP Chemicals Hull, UK

Abstract: In the mid 1990's, BP's restructuring of its European Chemicals operation led to the requirement for a world scale vinyl acetate monomer (VAM) manufacturing facility. The traditional fixed bed process would require too much investment - new technology was required to quickly unlock the next generation process.

BP focused its efforts into the development of alternative catalyst and reactor technologies. LEAP fluidized bed technology had demonstrated its potential at micro reactor scale, but the challenge was to take this technology to full-scale operation by 2001.

Fluid bed processes are difficult to scale up, as the complex interactions between process chemistry and fluid dynamics are difficult to establish at actual operating conditions. Conventionally, such processes pass through a 'demonstration' phase (a small scale commercial unit), which in this case would have led to an additional cost of $20-30M and an unacceptable delay of three to four years in commercial implementation.

In order to solve this problem, the development team broke down the challenge and developed techniques to understand each key step. The key challenges were:

Formulating a precious metal catalyst in fluid bed form
Establishing fluid dynamics and reactor design criteria for a fluidized bed.

X-ray imaging in BP's unique VIPA (Visualization, Imaging and Process Analysis) center was used to view and understand the fluid dynamics of a commercial scale reactor. The imaging process identified the best catalyst for fluidization and assessed the optimum use of various reactor internals. A unit containing the proposed internals was set up and comprehensive experiments were undertaken to assess their combined performance. This unit, whilst 70 times larger than the pilot plant was still 200 times smaller than the full-scale reactor.

A small pilot plant demonstrated the viability of the chemistry. Modeling was then used to combine the results in order to scale up pilot plant results by a size factor of 14,000 to the commercial plant scale. The resulting process started up successfully at the end of 2001. Within two hours of turning on the oxygen, the plant was producing on specification vinyl acetate. The fluidized bed had saved 30% in capital costs. This innovative route reduced the development time by three to four years.

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