Process for producing biodiesel with reduced monoacylglycerol content

A post-treatment process for crude biodiesel containing residual monoacylglycerol (MAG) and comprising the steps of:

• (a) providing a crude biodiesel;
• (b) contacting said crude biodiesel with a concentrated alkaline solution, and agitating the resulting mixture, to obtain a concentrated alkaline treated biodiesel;
• (c) contacting said concentrated alkaline treated biodiesel of step (b) with a recycled water and agitating the resulting mixture to obtain a first agitated mixture;
• (d) phase separating said first agitated mixture resulting from step (c) to obtain a pre-washed biodiesel and a spent water phase;
• (e) contacting said pre-washed biodiesel of step (d) with acidic water and agitating the resulting mixture to obtain a second agitated mixture;
• (f) phase separating said second agitated mixture of step (e) to obtain a water phase which is recycled in step (c) as said recycled water, and a fully washed biodiesel;
• and
• (g) drying said fully washed biodiesel of step (f) to obtain a purified biodiesel, wherein, the concentrated alkaline solution used in step b) is at least 5 mol/L and a volume of the concentrated biodiesel of step (f) is max 1% of the volume of said crude biodiesel, and wherein the residual concentration in MAG of the purified biodiesel does not exceed 0.4%.