Biodiesel production from residual cooking oils and purification by adsorption processes based on adsorbents of natural origin Conference Paper uri icon

abstract

  • The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UIDB/0690/2020).
  • Total global energy consumption has increased significantly in recent decades. International Energy Agency predicts that from 2012 to 2040, and also the International Energy Agency (IEA), by 2030, the world's demand for energy will increase by 50%. Nowadays, the main sources of energy supply in the world are oil, coal and natural gas. In addition to the environmental problems, the supply of fossil fuels is limited, which makes many researchers increasingly interested in exploring alternative energy sources [1]. In this pursuit, biofuels are promising renewable energy sources with lower carbon emissions, besides the possibility of being made from a variety of resources, including residues such as waste cooking oil (WCO), oily sludge from factories, and discarded animal fats [2]. In contrast to petroleum-derived diesel, biodiesel is renewable, biodegradable, non-toxic, sulphur-free and aromatic carcinogen-free [3]. The cost of biodiesel is now 10% to 50% higher than petroleum diesel. A more possible way to increase biodiesel production is to use WCO as a feedstock, which is 25% to 40% of the price of edible oil. This way, WCO gets a better destination than its discard [3]. Biodiesel is produced through transesterification/esterification which are reactions that convert oils or free fatty acids into alkyl esters. Through transesterification, the triglycerides react with small chain alcohol in order to obtain methyl or ethyl esters of fatty acids and glycerol. The process occurs in three reversible and consecutive reactions, which produce molecules of diglycerides and monoglycerides as intermediates [4]. The properties of biodiesel will depend on the feedstock used in its production, and it should be similar to petroleum diesel in order to be functional in motors without any changes. All parameters, such as cetane number, fatty acid methyl esters content, density, and acid value, are defined by standards and vary depending on the location. For example, in Europe, they are defined by the European Biodiesel Standard EN 14214, whose last version was published in 2008. It is set to specify characteristics that define the behaviour of biodiesel combustion in an engine and also the methods that have to be used to determine those parameters

publication date

  • January 1, 2022