Biodiesel fuel (BDF) has attracted attention as an alternative fossil fuel. BDF comprises fatty acid methyl esters (FAME) produced generally from triacylglycerols (TG) in vegetable oils treated with methanol. In Europe, BDF is manufactured from virgin vegetable oils grown on vast farmlands, while in Japan, where cultivation areas are small, it is manufactured from used cooking oils. Used cooking oils in Japan partly come from animal fats, which produce free fatty acids (FFAs) upon degradation. FFAs react with an alkali hydroxide used as the catalyst, and the produced soap brings about decrease a BDF yield. Since a massive amount of waste water due to homogeneous alkali catalysis of alkali hydroxide dissolved in methanol is discharged from the producing process, the post-processing is required. Due to these limitations, the applicability of the anion exchange resins as alternatives to the alkali catalyst was examined. It was clarified that the anion exchange resin was activated by binding with methoxide ions, which are regenerated during transesterification, allowing for their reuse. Compared to the hydroxide-type resins that are deactivated by adsorption of FFAs generated during the reaction, the methoxide-type resins maintain their activity, as no FFA is generated. Such deactivation could be controlled by esterifying FFAs with cation exchange resins before transesterification.

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Biomass resources have huge potential to secure energy supply in next decades with carbon neutral emissions. However, the resources itself are widely scattered diffusely throughout the country, and the capacity of utilization plant highly depends on the quantity of primary resources available. The study focuses on the equilibrium between resource supply and energy demand in Tohoku area in Japan, considering geographical distribution and transportation paths. Woody biomass and agricultural residues are introduced in the study as a co-firing fuel supplied to three coal power stations in Tohoku area. The biomass energy system is modeled and analyzed using both geographic information solver and the roadway condition data. In particular, resource supply such as biomass resource collection, preprocessing before transportation, storage, long distance transportation, and energy conversion to electricity, is modeled and introduced to the system. As a result of the model analysis, a supply curve of biomass resources is obtained, which shows a relationship between procurement cost for power supply and annual electricity production at coal power stations. The supply curve shows that an electricity of 4.3 × 108 kWh/yr can be supplied with the procurement cost of 10 JPY/kWh, and the maximum electricity reaches 12.7 × 108 kWh/yr with the procurement cost of 14 JPY/kWh.

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The effectiveness of bio-oils' heterogeneously-catalyzed ethanolysis, using groundnut (Arachis hypogaea) crude oil, activated calcium oxide (h-CaO), and surface-modified activated calcium oxide (s-CaO) for biodiesel production in developing countries, was studied in comparison with potassium hydroxide (KOH) and calcium hydroxide [Ca(OH)₂] in terms of reaction, effect of catalyst type and loading of 1.0 wt%, molar ratio of 9:1, time ranging from 0.5 to 3.0 h, at 78 °C and stirring speed of 1000 rpm. Ca(OH)₂ was inferior to KOH, h-CaO and s-CaO regardless of reaction time, achieving fatty acid ethyl esters (FAEE) yields, after 0.5, 2, and 3 h, of 0.24 ± 0.03 wt%, 1.09 ± 0.72 wt%, 8.08 ± 0.80 wt% comparing 56.19 ± 1.98 wt%, 76.57 ± 2.20 wt%, 76.99 ± 4.18 wt% , and 62.32 ± 1.95 wt%, 88.81 ± 0.82 wt%, 85.30 ± 4.56 wt%, and 51.40 ± 1.76 wt%, 81.21 ± 1.30 wt%, 83.23 ± 1.09 wt%, respectively. The activity of h-CaO, s-CaO and KOH agreed quite well showing the comparable effectiveness of the catalysts on ethanolysis. Generally, yields decreased after 2-h, due to product adsorption after 2 h. We based on these results and concluded that this paper is the first to report the effectiveness of h-CaO and s-CaO for bio-oil heterogeneously catalyzed ethanolysis for sustainable biodiesel production in developing countries.

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