| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Fischer-Tropsch synthesis (FTS) is known as a method for producing clean liquid fuel from syngas. Because syngas is easily produced by organic sources such as natural gas, coal and biomass, FTS is expected as a production method of liquid fuels instead of petroleum fuels. The FTS oil contains large amount of normal paraffins, which has high cetane number but with low octane number, near zero. Thus, in order to obtain gasoline from FTS oil, hydrocracking of FTS oil is required to increase the octane number. Hybrid catalysts composed of FTS catalysts and zeolite can produced directly gasoline fractions from syngas. However water produced from FTS deactivate zeolite in FTS catalysts and loss catalytic activity for hydrocracking.
It is well known that supercritical conditions have excellent features for heat transfer and solubility of both organic and inorganic materials. Liquid butane does not dissolve water, but supercritical butane does. Therefore, when FTS is carried out in supercritical butane, water is removed from the hybrid catalyst and deactivation of the catalyst will be prevented.
The hybrid FTS catalyst was prepared from the mixing of 10 wt% Co/SiO_2 and β-zeolite. FTS was carried out using the hybrid catalyst and syngas (H_2/CO=2) in supercritical butane. When the conditions were changed from gas phase to supercritical one, the CO conversion was increased from 62 to 72 %, and CO_2 selectivity was decreased to from 8.3 to 3.3 %. The ratio of n-paraffin to isoparaffin decreased from 4.2 to 2.7. These results indicated the supercritical conditions enhanced isomerization reactions and produced gasoline fractions effectively.
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