Method for preparing biodiesel by self-catalytic esterification and ester interchange

Abstract

The invention discloses a method for preparing biodiesel by self-catalytic esterification and ester interchange. In the method, waste acid grease such as plant oil asphalt, acidified oil, monomer acid, neutral oil and swill-cooked dirty oil are blended to form oil with certain acidity, the blended oil reacts with a lower alcohol under the condition that the acidity of the grease serves as a catalyst, namely an self-catalyzed reaction is performed, the process is simple, the product is high in purity and the cost is low. The method for preparing biodiesel by self-catalytic esterification and ester interchange comprises the step putting raw oil with an acid value of 50 to 200mgKOH / g and alcohol into a high-pressure kettle in proportion to perform a reaction under 3 to 10 MPa and at 200 to 280 DEG C for 9 to 28 hours to obtain the biodiesel product.

Description

technical field [0001] The invention relates to a production method of biodiesel, more specifically to a production method of self-catalyzed esterification and transesterification of biodiesel Background technique [0002] Biodiesel is a mixture of fatty acid esters, such as fatty acid methyl ester, fatty acid ethyl ester, fatty acid propyl ester, etc., obtained by transesterification of animal and vegetable oils and low molecular weight alcohols (such as methanol, ethanol, etc.). It is an environmentally friendly fuel and has the following advantages compared with diesel: (1) The raw material comes from renewable animal and vegetable oils or waste oils, which can reduce the dependence on petroleum; (2) It has excellent environmental protection characteristics. Exhaust gas poisoning, particulate matter and CO 2 and CO emissions, which are about 10%, 20% and 10% of ordinary diesel, respectively, SO 2 And sulfide emissions are low, and will not release polyaromatics or other...

AI Technical Summary

Problems solved by technology

The bio-enzyme catalysis method uses microbial lipase as a catalyst for transesterification reaction. This method overcomes the shortcomings of poor chemical reaction selectivity, many by-products and impurities, and difficult to handle.

The supercritical method uses animal and vegetable oils and supercritical alcohols to undergo transesterification reactions. This method does not require a catalyst, the reaction time is short, and the post-treatment is simple. However, the operating conditions of this method are relatively harsh, requiring high reaction temperature and pressure. The equipment requirements are also very high, which is not suitable for large-scale production