Progress on Modified Calcium Oxide Derived Waste-Shell Catalysts for Biodiesel Production

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous catalyst at an economical price has been studied widely for biodiesel production. It was noted that various types of natural waste shell are a potential calcium resource for generation of bio-based CaO, with comparable chemical characteristics, that greatly enhance the transesterification activity. However, CaO catalyzed transesterification is limited in its stability and studies have shown deterioration of catalytic reactivity when the catalyst is reused for several cycles. For this reason, different approaches are reviewed in the present study, which focuses on modification of waste-shell derived CaO based catalyst with the aim of better transesterification reactivity and high reusability of the catalyst for biodiesel production. The catalyst stability and leaching profile of the modified waste shell derived CaO is discussed. In addition, a critical discussion of the structure, composition of the waste shell, mechanism of CaO catalyzed reaction, recent progress in biodiesel reactor systems and challenges in the industrial sector are also included in this review

Feasibility of advancing the production of bio-jet fuel via microwave reactor under low reaction temperature

Catalytic reduction of oxygen-containing compounds in palm kernel oil has been studied under H2-free atmosphere condition using microwave system approach over Raney nickel and magnetite activated carbon-based catalysts. The role of porous structure and active O-containing groups of magnetite activated carbon (FeMo/ACB) catalyst during deoxygenation (DO) at 250 °C was investigated. Activated carbon catalysts, obtained from bamboo-derived biochar activation at 800 °C with KOH exhibited large surface area and O-containing group. With the introduction of the FeMo/ACB catalyst, the relative content of bio-jet fuel increased remarkably (∼80%) with the bio-jet fuel selectivity of ∼80%. Noted, the high DO activity also showed strong correlation with the presence of high acidic sites, high porosity and surface on the bamboo-derived carbon support, which in turn allows the active metals Fe-Mo to coat the ACB support thoroughly thus promoting a more efficient DO reaction. In addition, the FeMo/ACB catalyst showed excellent reusability over five consecutive cycles, with hydrocarbon fractions ranging from 62% to 80% and bio-jet fuel selectivity from 65% to 80% and minimum coke formation (< 2 wt%)