Yoichi Aihara’s research while affiliated with National Institute of Advanced Industrial Science and Technology and other places

Waste cooking oils were studied as the raw material for biodiesel production using calcium oxide as the solid base catalyst in refluxing methanol. Edible soybean oil and waste cooking oil from restaurants were converted into biodiesel completely within 2 hr. However, catalyst recovery after the reaction markedly decreased for the waste cooking oil, due to dissolution of the solid base catalyst. Most of the solid base catalyst was converted into calcium methoxide and glyceroxide, and trace of saponified calcium was collected after the reaction of the waste cooking oil. Waste cooking oil from homes increased the catalyst recovery, in comparison with waste oil from restaurants. The catalyst recovery was considerably improved by a removal of free fatty acids. Both polar fraction and moisture in the waste cooking oil were minor poisons for the solid base catalyst. Based on the results, improvement of the biodiesel production requires protection for the solid base catalyst from the poisoning species contained in the waste cooking oil.

Light (LGO) and heavy or vacuum gas oil (VGO) fractions from mixed Middle East crudes and respective fractions from a typical Canadian oil sands bitumen-derived synthetic crude oil (SCO) were blended at various ratios (≤ 40%) and hydrotreated to investigate the kinetics of sulfur and nitrogen removal, and product quality. Hydrotreatment was carried out in down-flow micro reactors over commercially available NiMo/Al 2O 3 and CoMo/Al 2O 3 catalysts, varying reactor temperature (350°-390°C), pressure (5-10 MPa), and space velocity (1-6/hr). Blending the LGO with SCO enhanced both sulfur and nitrogen removal from Middle East crude LGO. The CO and hydrocarbon emissions from the blended LGO were slightly higher than those from 100% Middle East crude LGO, but NO x emissions were lower. The effect of SCO blending on particulate matter (PM) emissions was inconclusive. The CO, HC, and PM emissions could be correlated by total and polyaromatics, and clear cetane number (without additives). By blending the Middle East crude VGO with the oil sands-derived VGO, the sulfur content was decreased that is beneficial in reducing the sulfur content of FCC products. The FCC yields were predicted based on the properties of the feeds (hydrotreated products) using previously prepared correlations. The yields of LPG and gasoline from the blended VGO decreased at the expense of light and heavy cycle oils under the same operating conditions, but the difference was insignificant and could be overcome by slightly increasing the severity of either the FCC pre-treater or the FCC unit.

Transesterification of soybean oil was carried out with methanol over calcium oxide at methanol refluxing temperature, in order to study the application of heterogeneous catalytic process to biodiesel production. The catalyst samples were prepared by calcination of the precipitated calcium carbonate at 900°C in the prescribed atmosphere, an ambient air or a helium gas flow. Calcium oxide prepared in an ambient air catalyzed the transesterification of soybean oil, but yield of the fatty acid methyl esters was only 10% for 4h. The calcination in a helium gas flow markedly intensified the activity of calcium oxide, as the obtained catalyst sample completed the transesterification for 2h. The obtained oil after completing the transesterification had appropriate properties for diesel fuel oil. The active catalyst prepared in a helium gas flow has a higher base strength (15.0 < H_ < 18.4) than the dull one in an ambient air (9.3 < H_ < 15.0). Additionally, the base quantity was 5times larger for the active catalyst. The dull catalyst could be activated by calcination at 300°C in a helium gas flow. The poisoning species in an ambient air was elucidated through the activity test for a series of the catalyst sample obtained by conditioning the partial pressure of CO 2 and moisture in the calcining atmosphere.