Biodiesel Production from an Olive Oil Industry Waste

DEBORATH REINOSO; MARIANA ALVAREZ SERAFINI; GABRIELA TONETTO

Congreso; 2nd RCN Conference on Pan American Biofuels & Bioenergy Sustainability; 2016

AiChE

With the growth of global energy demand and high levels of pollution, sustainable fuel alternatives have become a high priority for many countries. Biodiesel is one of these sustainable fuels obtained from vegetable oils or animal fats. Consists of alkyl esters derived from either the transesterification of triglycerides or the esterification of free fatty acids with short-chained alcohols. Biodiesel comes with many advantages; low emissions of CO2 compared to petroleum diesel, biodegradable, non-toxic. Argentina is currently one of the major biodiesel producer worldwide, using soybean oil as raw material. In the country, the diesel must contain 10% biodiesel since 2014. Biofuel production programs have several social and environmental impacts and affected food markets through diverting grain away from food for fuel. Therefore, utilizing biomass residues for biodiesel production will reduce its contribution to food price. Also, the use of cheap low quality feed stocks will help in improving the economic feasibility of biodiesel.Biomass (such as agricultural residues, animal wastes, forestry and wood processing residues, municipal or industrial wastes) is seen as one of the most promising, renewable energy sources because it can be converted to other usable forms of energy, like biofuels. It is relatively cheap energy resource to provide the initial feedstock in bioenergy industry. This would mean the elimination of a waste stream and gives biofuel producer a chance to reduce costs.Alperujo is a waste product from the process of olive oil extraction (two-phase extraction process). It is a blend made of water, oil, cellulose, lignin, proteins, carbohydrates, small portions of active phenol compounds and other derivatives. It is not environment-friendly and it leads to serious ecological problems once alperujo is scattered on the soil. It has a phototoxic activity that does not permit plants to germinate. Olive plantations in Argentina are rapidly expanding, therefore alperujo is a waste to the environment that needs to be treated.In the industry is used an alkaline homogeneous catalyst. One of the main problems of these catalysts is the difficulty in using low-cost raw material, such as the formation of soap due to the neutralization of free fatty acids present in low-quality oils, or the saponification of triglycerides in the presence of water. The use of a heterogeneous catalyst would simplify the separation and purification steps. There is a growing interest in finding a solid catalyst that is active in the transesterification of triglycerides, while it is selective with raw materials of low quality, that is to say a catalyst that is stable in the presence of FFA and water. Given that it will be used in ?green? processes, it should also be non-pollutant and non-toxic. In this study, alperujo has been successfully used as feedstock to obtain biodiesel using zinc stearate as a new clean catalyst for an environmentally-friendly biodiesel production. The catalyst was able to catalyze simultaneously the triglyceride transesterification and the fatty acid esterification reactions with high activity and selectivity under moderate operating conditions.