Why is acid added during the extraction process of biodiesel?

Why is acid added during the extraction process of biodiesel?

Both glycerol and biodiesel need to have alcohol removed and recycled in the process. The wash water is separated out similar to solvent extraction (it contains some glycerol), and the trace water is evaporated out of the biodiesel. Acid is added to the glycerol in order to provide neutralized glycerol.

How can biodiesel be made from fatty acids?

The transesterification of vegetable oils, animal fats or waste cooking oils is the process behind conventional biodiesel. In the transesterification process a glyceride reacts with an alcohol (typically methanol or ethanol) in the presence of a catalyst forming fatty acid alkyl esters and an alcohol.

Why do fatty acid esters the biodiesel and glycerol separate into different layers?

As a consequence, the non-polar methyl ester molecules making up the biodiesel do not mix with the polar glycerol molecules and the mixture of products will separate into two layers with the less dense biodiesel floating on top of the more dense glycerol layer.

What fatty acids are in biodiesel?

The fatty acids in the high-acid oil-biodiesel primarily comprised 38.91 wt % oleic acid (C18:1), 25.38 wt % linoleic acid (C18:2), and 22.31 wt % palmitic acid (C16:0), as shown in Table 2. These three fatty acid compounds accounted for 86.5 wt % of the total fatty acid content.

What is the reason that transesterification is commonly used in biodiesel production?

Transesterification is a chemical reaction used for the conversion of triglycerides (fats) contained in oils, (Feedstocks) into usable biodiesel. Biodiesel produced by the process of transesterification has a much lower viscosity, making it capable of replacing petroleum diesel in diesel engines.

Why is transesterification important for biodiesel?

Transesterification is an imperative process for biodiesel production, as it can reduce the viscosity of the feedstock/vegetable oils to a level closer to the conventional fossil-based diesel oil [20].

Why is transesterification done?

Why biodiesel is known as green fuel?

As described in Biodiesel Benefits and Considerations by The U.S. Department of Energy, the use of biodiesel reduces the greenhouse gas emission because the carbon dioxide that is produced during burning is balanced by the carbon dioxide that is absorbed while cultivating the crops used in the manufacture of the …

How is glycerol separated from biodiesel?

Due to its low solubility in esters, separation is usually performed by either decantation or centrifugation. In the separation by decantation, the biodiesel and glycerol mixture is rested in tanks. The separation cost is low, but it is a slow process.

How can production of free fatty acids impact Biodiesel Production?

However, the high free fatty acids (FFA) content in waste cooking oils can greatly reduce the efficiency of the alkali-catalyzed transesterification reaction that is most commonly used in making biodiesel.

How are fatty acid methyl esters prepared?

Saponification followed by methylation is a classical method for preparation of fatty acid methyl esters (FAMEs) from glycerolipids and sterol esters (SEs). Conventionally, FAMEs are prepared by base- or acid-catalyzed esterification.

Why does transesterification process occur?

Transesterification is one of the reversible reactions and proceeds essentially by mixing the reactants. However, the presence of a catalyst (a strong acid or base) accelerates the conversion and a little excess of alcohol is used to shift the equilibrium toward the formation of fatty acid alkyl esters and glycerol.

How are fatty acids used to make biodiesel?

Most of the bulk of the molecule (as well as the energy contained therein) is in the long hydrocarbon chains called fatty acid chains that are attached to it. As long as an oil or fat has this basic structure, it is a good candidate for being turned into biodiesel.

Why is biodiesel the fuel of the future?

Biodiesel is gaining more and more importance as an attractive fuel due to the depleting fossil fuel resources. Chemically biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats.

How is vegetable oil used to make biodiesel?

Chemically biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst to give the corresponding monoalkyl esters.

How are hydrogenated oils used to make biodiesel?

Effect of Fatty Acid Structure on Biodiesel. Hydrogenated oils are oils in which atoms of hydrogen have been added to the vicinity of the double bond. This converts it to a single bond. A molecule of oil in which all of the double bonds have been hydrogenated is chemically identical to a standard saturated fat.