Biodiesel production from non food feedstocks using a bifunctional heterogeneous catalyst and glycerol byproduct utilization
Chemical and Materials Engineering
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Biodiesel is a fuel comprised of monoalkyl esters of long chain fatty acids derived from vegetable oils or animal fats. In the biodiesel industry, most biodiesel production is made from food sources, such as vegetable oils. The production of biodiesel from renewable and waste materials is an attractive alternative to the conventional agricultural feed stocks such a corn and soybean. The conventional biodiesel production process poses several problems in processing feedstocks with high free fatty acids (FFAs) such as waste vegetable oils, in separation and purification of biodiesel. An efficient and clean process is required for large-scale production to make the biodiesel industry more sustainable. Heterogeneous solid catalysts have the potential to eliminate these problems, regardless of feedstock. The glycerol is a byproduct of the biodiesel industry. Crude glycerol processing is expensive. Heterogeneous catalysis offers a solution to this problem by selective conversion of glycerol into value added chemicals.In this study, two new feedstocks, for biodiesel production namely spent coffee grounds and feathermeal have been explored. A bifunctional heterogeneous catalyst has been developed for successful conversion of high FFA feedstocks into biodiesel and a cost effective, highly selective catalyst has been discovered for glycerol oxidation to glyceric acid.Spent coffee grounds yield 10-15% oil depending on the coffee species (e.g., arabica, robusta). The biodiesel derived from the coffee grounds (100% conversion of oil to biodiesel) was found to be stable for more than one month under ambient conditions due to inherent antioxidants. Coffee grounds after oil extraction are ideal materials for garden fertilizer, feedstock for ethanol, biochar, bio-oil and as fuel pellets.Chicken feather meal contains 11-15% fat content. This project describes an environmentally friendly approach to extract the fat content using water as a solvent for biodiesel production. Currently, feather meal has been used as an animal feed (high protein content) and as a fertilizer (high nitrogen content). The feather meal can be used to extract biodiesel feedstock (triglycerides) without altering, rather improving its existing uses as a better animal feed and a better fertilizer. A method has been developed to produce biodiesel using Quintinite-3T (Q-3T) as a heterogeneous bifunctional catalyst. The reaction can be carried out using high FFAs containing feedstocks as well. The reaction times were shorter when compared to those for the existing heterogeneous catalysts. In this work, a complete characterization of Q-3T, catalytical activity, including acidic and basic site studies and catalyst recycling studies is presented. Titanium disilicide (TiSi2) was identified as a cost effective and selective catalyst for conversion of glycerol into glyceric acid. An investigative study of in situ glycerol oxidation in aqueous media is reported.