FT Microchannel reactor technology: what it is, why it’s getting traction
3-core FT microchannel reactor from Velocys
Last week, we advised that the FT microchannel reactor technology developed by the Oxford Catalysts Group and marketed under the brand name Velocys, has been selected for use in the design and possible construction of a commercial Biomass-to-Liquids (BTL) plant led by the IR1 Group. The plant convert around 170,000 tons per year of forestry derived biomass into approximately 1,100 barrels per day of liquid transportation fuels.
Which raises the question — what exactly are FT microchannel reactors?
On that topic, UK-based freelance science writer Nina Morgan writes:
Microchannel Fischer-Tropsch (FT) reactors
Microchannel technology is a developing field of chemical processing that intensifies chemical reactions. It enables lower cost, smaller and more productive processes by improving the heat and mass transfer performance and reducing the dimensions of the reactor systems. Mass and heat transfer limitations reduce the efficiency of the conventional large FT reactors. The use of microchannel technology makes it possible to overcome these limitations and to intensify the chemical reactions, enabling them to occur at significantly higher rates than in conventional systems.
Microchannel FT reactors are compact reactors containing thousands of channels with characteristic dimensions in the millimetre range. The FT process is highly exothermic, or heat generating.
In microchannel FT reactors process channels, filled with catalyst, are interleaved with water-filled coolant channels. The small-sized channels dissipate heat more quickly than conventional fixed-bed reactors with relatively larger tubes in the 2.5 – 10 cm (1 – 4 inch) range. As a result, more active catalysts can be used.
Microchannel FT reactors marketed under the brand name Velocys, and using a highly active FT catalyst developed by Oxford Catalysts Ltd have been successfully tested at the laboratory, pilot and demonstration scales. A further field demonstration incorporating the microchannel FT technology is expected to be qualified during the second half of 2013.
The reactors exhibit conversion efficiencies in the range of 70% per pass, and are designed for economical production on a scale that matches the resource. Modular plants incorporation microchannel FT reactors will operate economically at capacities of around 1000 barrels per day (bbls/day). In contrast, conventional FT plants are designed to work at minimum capacities of 5000 bbls/day, and function well and economically at capacities of 30 000 bbls/day or higher – a scale that would be impractical for BTL plants.
Microchannel Biomass to Liquids (BTL)
BTL is a process used to convert waste biomass into high quality liquid fuels that are totally compatible with petroleum-based fuels. The fuels produced via BTL can be used in existing engines and infrastructure.
The BTL process involves two main operations: production of a synthesis gas (syngas), a mixture of hydrogen and carbon monoxide, using a gasifier, followed by Fischer-Tropsch (FT) synthesis. In the FT process, first developed he 1920s and 1930s to produce liquid fuel from coal, the syngas is converted is converted into paraffinic hydrocarbons over a cobalt catalyst.
The resulting product can then be upgraded via hydrocracking and fractionation to produce a range of liquid hydrocarbon fuels. These include diesel, jet fuel, naphtha, and waxes and base oils for synthetic lubricants. Because they contain virtually no sulphur compounds or aromatics these products generally are of higher quality than those derived by conventional means.
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