(731e) Proposal for an Upcycling Process to Commercialize All Components of By-Product Oil in Edible Oil Refinery

Vegetable oils are important for us, not just for food but also for industrial uses. Every year, the world produces about 215 million tons of these oils, and the amount grows by 5% each year. Out of this total, 60% is used for food, 15% goes into making chemicals known oleochemicals, and the remaining 25% is turned into biodiesel fuel. In addition to these primary uses, about 20% of the oils processed are inedible and become by-products during the refining process. Currently, these by-product oils, rich in fatty acids and containing a few functional ingredients, are incinerated for heat recovery due to the absence of economically viable technologies for their efficient utilization.

Elemental technologies have been developed to convert fatty acids, their primary component, into biodiesel via esterification, or to separate and recover trace functional ingredients. However, conditions of high temperature and reduced pressure are required to suppress the reverse reaction in esterification and to utilize multi-stage molecular distillation in the recovery process. As a result, these requirements lead to high energy consumption and low overall efficiency, creating significant challenges for the viability and sustainability of these technologies.

Table 1 details the content and generation volumes of each component in the distillation by-products obtained from the deodorization process of four types of plants. It also presents the potential value of these components as functional ingredients, along with their market prices and growth rates (Compound Annual Growth Rate, CAGR). For fatty acids and triglycerides, the table shows the prices when converted into fatty acid esters, which can be used as biodiesel.

We have therefore developed an integrated reaction separation process aimed at commercializing all components found in these by-products. The key technology behind this innovation is a continuous reaction separation process that utilizes ion exchange resins as both catalysts and adsorbents. As previously reported¹⁾, this method enables the simultaneous complete conversion of fatty acids and triglycerides into esters and the separation of phenolic functional ingredients such as vitamin E with high purity. Remarkably, this process operates under mild conditions at 50°C and atmospheric pressure.

Our findings reveal that when paraffins are present in the distillate oil, they precipitate at room temperature due to their low solubility in the fatty acid ester-alcohol solution. By washing with alcohol, we have successfully recovered the paraffins purity to more than 95%. Notably, with a melting point of about 60℃, this substance proves to be an excellent base material for lipstick, benefiting from its card house structure. As this is the world's first biomass-derived product of its kind, we have also registered CAS numbers for them. Furthermore, when phytosterols are contained in the distillate oil, they automatically precipitate out after the distillation for alcohol recovery due to their low solubility in fatty acid esters, enabling their recovery with over 95% purity. The remainder is mainly fatty acid esters, which are used as biofuels for vehicles and power generation.

We have already established a practical process for rice bran oil distillate, confirming that its potential value can be realized as planned. Currently, we are advancing the demonstration of this process for palm distillate oil.

1)Hiromori et al., J.Clean.Prod.,189, 223-230(2018)