Variation of density and flash point in acid degummed waste cooking oil

Recycling of waste cooking oil represents a source of convenient raw materials for industry. Within the large number of products derived from the treatment of waste cooking oil, eco-friendly lubricants grown in importance during the last years. Recycling process for such application consists usually of acid or basic degumming followed by a filtration step. The effect of the specific type of acid degumming on the density and on the flash point of the recycled oil was evaluated employing full factorial design. Two mathematical equations were derived which allow to estimate respectively the density and the flash point of the recycled oil, depending on the: (a) pH of the washing solution, (b) oil/water ratio, (c) temperature of the system, and (d) the stirring time. Practical applications: Recycle of waste cooking oil presents several advantages. Mainly it is beneficial for the environment and considered as mandatory by law in several countries, and could furnish a useful low price raw material for several kind of industries. Recently, a multitude of local small scale industries have based their business on this topic and the recycling process employed often consists in a degumming step followed by filtration. This article deals with the tuning of the main parameters of the degumming step related with the density and the flash point of the final product. These parameters are important especially for lubricant synthesis.