Biodiesel Production from Unrefined Palm Oil on Pilot Plant Scale

Abstract

As global warming and climate change issues are defying modern society sustainable development; biofuels, biodiesel included, are among promising solutions. Biodiesel is generally produced from renewable vegetable oils and animal fats via acid or base catalyzed transesterification. Depending on regional availability, biodiesel production feedstocks vary from vegetable oils such as rapeseed oil, soya oil, palm oil, and jatropha oil, to used cooking oil and animal fats, with each type of feedstock presenting its own process challenges rooting from its chemical composition. This paper reports about biodiesel production from crude palm oil on a pilot plant scale, subsequent to a laboratory scale investigation of biodiesel synthesis from various vegetable oil feedstocks. Prior to transesterification, pretreatment processes have been applied due to the fact that crude palm oil as a biodiesel feedstock possesses a high free fatty acid(FFA) content, water, solid impurities and waxes, all of which hinder an efficient transesterification if not dealt with accordingly. Those processes are mainly filtering, water evaporation, and FFA esterification which is done with 99.9% methanol and 96% sulfuric acid as a catalyst. In fact, the acid esterification process successfully handles the raw palm oil despite its high FFA content of 16.9%, and biodiesel is produced from that feedstock with a yield of 90.4%. A two steps transesterification is carried out using potassium methylate 32% in methanol as a catalyst and anhydrous methanol too. Laboratory analyses have also been used to monitor the process and assess the final product quality. Furthermore, biodiesel cold filtering and top layer intake tank systems of a filling station, both proved to be efficient at helping to obtain a refined product by getting rid of suspensions appearing in biodiesel at room temperature due to sterol glucosides and waxes.