(49b) Fischer-Tropsch Synthesis: Where We Are and Where We May GO

The Germans followed a simple plan when they scaled up the Fischer-Tropsch (FT) synthesis to the commercial level. For the reactor, they set a simple goal: fixed-bed reactors that were sized to produce 15 bbl/day and operate at atmospheric pressure. To attain the desired plant size, they utilized as many of the 15 bbl/day reactors as were needed.  A driving force in industry, at least since about 1950, has been “economy of scale” and this philosophy has been followed by the developers of the F-T synthesis. Both Sasol and Shell, the two commercial leaders to date, have followed the “economy of scale” in their development of FT. Thus, today Sasol is operating a slurry reactor in Qatar that produces 17,500 bbl/day and the reactor is the largest that equipment for its manufacture will allow today. Likewise, Shell has reached the limit of the size of reactor shell that can be manufactured today and the number of fixed-bed reactor tubes that can be placed in the reactor shell. Thus, until sufficient plant construction makes it economical to scale up reactor production equipment it appears that the “economy of scale” for the FT reactor has reached a plateau. At the present time, productivity increases from the reactor will come from improved design and operation of current sized reactors.  The size of the FT reactor seems to have reached its limit. Thus, there is a need to define an approach that permits one to operate effectively at a small scale. At least two factors are driving this consideration: (1) the need to utilize renewables to reduce the carbon footprint of synthetic transportation fuels and (2) the need to eliminate methane release at remote oil producing areas. Microchannel reactors have been considered for this purpose and they have been operated at the pilot plant scale.  Much still needs to be accomplished both in the manufacturing area and in developing the scientific and engineering understanding to effectively utilize this reactor.