NOVELTY - Biodiesel production involves passing used oil through a filter press in order to remove impurities and heating at 85 degrees C approximately by using a tank equipped with an insulating polyurethane beg and an internal coil arranged horizontally in heat exchanger. A stable temperature is achieved inside the tank by circulating water at 85 degrees C without energy loss. Another tank is fitted with a stirring system for blades for mixing methanol and sulfuric acid in a predetermined ratio that depends on amount of free fatty acids in the used oil.    USE - Method for producing biodiesel from used vegetable oils.    ADVANTAGE - The method produces high quality biodiesel in a simple and cost-effective manner by reducing consumption of reagents, alcohol and catalyst. The reaction time is reduced to 20 minutes at atmospheric pressure.    DETAILED DESCRIPTION - Biodiesel production involves passing used oil through a filter press in order to remove impurities and heating at 85 degrees C approximately by using a tank equipped with an insulating polyurethane beg and an internal coil arranged horizontally in heat exchanger. A stable temperature is achieved inside the tank by circulating water at 85 degrees C without energy loss. Another tank is fitted with a stirring system for blades for mixing methanol and sulfuric acid in a predetermined ratio that depends on amount of free fatty acids in the used oil. The oil and reactants are mixed by using a turbine and then moved to esterification reactor. The esterification reactor comprises a piston, a coil and a perforated inner ring that is transversely arranged at different heights. The working temperature is 60 degrees C that is maintained by circulating hot water in the vertical coil, where the reactor works by ideal plug-flow pattern. The oil triglycerides are transesterified with methanol and alkaline catalysis at 60-65 degrees C, where the alkaline catalyst is sodium hydroxide. The esterification reactor mixture is neutralized with sodium methoxide, where the reaction mass is provided with rings on the reactor by decreasing interface between the reactants. The obtained product is transesterified with methanol, glycerin and biodiesel in a distillation column at 65-70 degrees C. The glycerol is decanted from bottom of the distillation and collected in a specific tank, where biodiesel is collected by central region of the distiller to lead final step of purification. The obtained biodiesel is washed with a pressure washer to remove soapy content.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of basic outline of biodiesel production method from vegetable oils.    Oil tank (1)    Sulfuric acid and methanol tank (2)    Methoxide tank (3)    Automated three-way valve (4)    Pump (5)    Turbine mixer (7)