Saturday, September 27, 2008

Opinion: CO2 to fuels processes

The Green Car Congress blog has an article on a CO2 to fuels process by a company called Carbon Sciences.
Important features of this process are:
1) The use of biocatalysts (enzymes?) to effect the transformations under mild conditions.
2) The use of relatively “dilute” CO2 streams, which could lower the costs for CO2 separation from power plant-flue-gas streams.
My graduate research is in a closely related area, the photocatalytic conversion of CO2 to fuels in which CO2 and water react upon light-induced electron transfer to/from a suitable photosensitizer. This reaction is not very efficient. On the other hand, the heterogeneous hydrogenation of CO2 with H2 is fairly effective (but involves high temperatures), a Japanese company, Mitsui Chemicals will begin the construction of a pilot plant this year to produce 100 T/year of methanol (CH3OH) from CO2 and solar-produced hydrogen.
My opinion:
The conversion of CO2 to fuels is a hydrogenation reaction (add hydrogen, remove oxygen). However, I could not find information on the Carbon Sciences website about their hydrogen source.
One wonders how effective the scale up of this biocatalytic process will be. The main questions for me here are the source of hydrogen, enzyme stability and costs, and the product separation and purification costs. These factors would determine if this process indeed is cheaper than the heterogeneous catalytic process (using Cu/ZnO-like catalysts).
Hat tip: Green Car Congress blog.

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1 comment:

control valves said...

I believe construction of such projects requires knowledge of engineering and management principles and business procedures, economics, and human behavior.

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