Aliphatic acids physical properties evaluation

Abstract EN

Biodiesel can be produced from pure fatty acids or from frying oil wastes.

To optimize biodiesel manufacturing, many reported studies have built simulation models to quantify the relationship between operating conditions and process performance.

For mass and energy balance simulations, it is essential to know the five fundamental thermophysical properties of the feed oil: liquid density (ρ), vapor pressure (Pvap), liquid heat capacity (Cp), heat of combustion (Hc) and heat of vaporization (ΔHvap).

So, adequate knowledge of physical properties of fatty acids is of great importance for predicting their methyl esters properties which are required to accurately simulate the fuel spray, atomization, combustion and emission formation processes of a diesel engine fueled with biodiesel.

In this work a methodology, for predicting liquid density (ρ), liquid heat capacity (Cp), heat of combustion (Hc), heat of vaporization (ΔHvap), liquid viscosity (), thermal liquid conductivity () and liquid surface tension () of aliphatic acids, is proposed.

This methodology will be applied to predict the mentioned above properties for the most of the available fatty acids with focusing an attention on five major fatty acids as they are the main components of oil resources of biodiesel production.

These acids are Palmitic acid, Stearic acid, Oleic acid, Linoleic acid and Linolenic acid.

For each physical property, the best prediction model has been identified.

Some experimental results regarding heat of combustion and heat of vaporization were also obtained.

The predicted values were compared with available experimental data and very good agreements have been obtained between the predicted results and the published data where available.

The calculated results can be used as key references for biodiesel combustion modeling.