Method for preparing biological diesel oil with series double-fixed bed and catalysis of solid catalyst

Abstract

A method for catalytically preparing bio-diesel by using tandem double fixed beds and solid catalyst comprises the following steps: selecting animal or vegetable oil exceeding acid value, fatty acid or neutral oil as the raw material, pre-reacting in a bed filled with solid acid to rapidly lower the acid value of the raw material oil, and adding into a bed filled with solid base catalyst to achieve high-efficiency transesterification reaction. Accordingly, high-purity bio-diesel can be obtained by double-bed catalysis adopting the pre-reaction, double-bed catalysis and once transesterification processes and adopting parallel-flow feeding and bed pressure manner to improve mass transfer. Meanwhile, the glycerol phase in the product can be easily separated and can be purified by vacuum rectification to obtain fine glycerol with purity above 98.5 percent, thus improving the use value of the product. The method has the advantages of wide materials, environment-friendly process, efficient product utilization, low investment cost, bright industrial future, etc.

Description

technical field [0001] The present invention relates to the technical field of biochemical new energy sources, in particular to a process method for preparing biodiesel by using series double fixed-bed solid acids, alkali catalysts to catalyze fatty acids, super-acid value animal and vegetable oils and neutral oils. Background technique [0002] Biodiesel (biodiesel) is a liquid fuel obtained by transesterification of vegetable oil, animal fat and fatty monoalcohol. The alkane number is superior to petrochemical diesel, and biodiesel can be mixed with petrochemical diesel in any proportion to make biodiesel blended fuel. On the other hand, biodiesel is mainly composed of three elements, C, H, and O. When burning to release heat, the product is H 2 O and CO 2 ,Green. [0003] There are many methods for preparing biodiesel, which are generally divided into physical methods and chemical methods. At present, the mainstream method of industrial biodiesel production is the tran...

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Problems solved by technology

In CN 132762A and CN 1412278A patents, it is reported that sulfuric acid or benzenesulfonic acid is used as a catalyst to prepare biodiesel. Although this type of catalyst has no special requirements on the free acid content in the raw oil, the liquid acid is easy to corrode equipment, and the post-treatment process is complicated, resulting in a large amount of waste water, polluting the environment and increasing treatment costs

In the literature vegetable oil preparation of biodiesel. Wu Guoying et al. Journal of Jiangsu Institute of Petrochemical Technology. 2002, 14 (13): 8-11 reported that using liquid alkali catalysts (such as KOH, NaOH, etc.) to prepare biodiesel, but the obtained by this method The product is easy to saponify, the catalyst is difficult to recycle, and the washing produces a large amount of waste water to pollute the environment, and the homogeneous base catalysis method requires the raw material to be neutral oil, which also limits the source of raw materials

In the patent CN1818026, it is reported that lipase is used as a catalyst to immobilize and catalyze the preparation of biodiesel. Although the reaction conditions are mild and continuous production is possible, the biological enzyme is easily poisoned and the reaction life is short, so this method is also difficult for large-scale industrial production.

It is reported in the patent CN 1594504A that the supercritical method is used to prepare biodiesel. Although the reaction time is short and the conversion rate is high, the requirements for the reaction equipment are relatively high, which increases the production cost.

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