Biomass energy prepared by one-step method of microalgae

Abstract

The invention provides a method for preparing biodiesel from microalgae. The method comprises the following steps of: a. changing collected microalgae from the wet algae into algae block or algae powder; b. mixing a catalyst into low-carbon alcohol, directly adding the algae block or the algae powder obtained by the step a, and carrying out ester exchange reaction to prepare the biodiesel; c. after the reaction is stopped, adding an organic solvent for extracting reaction solution which is divided into organic solvent phase used for extraction, low-carbon alcohol water-adding phase and algae mud; and d. after the extraction is completed, collecting the organic solvent phase used for extraction, removing the organic solvent by distillation, and obtaining oily liquid, namely crude products of the biodiesel. After preparing the biodiesel, the steps that the low-carbon alcohol water-adding phase is used circularly after dewatered by a solid drying agent, and the produced algae mud is used for producing biogas by biological fermentation are added. The invention completes the oil extraction of microalgae and biodiesel production by one step, simplifies the technique steps and equipment, saves cost; the sulphuric acid and low-carbon alcohol used for production can be recovered, then dewatered by drying, then utilized repeatedly, the cost is reduced, the final product is neutral, does not need washing and reduces the downstream processing pressure; and simultaneously, chlorophyll is mainly concentrated in the low-carbon alcohol, reduces the interference of the chlorophyll to the color of the product and does not need the step of decoloring.

Description

technical field [0001] The invention relates to the field of bioenergy, in particular to a method for preparing biodiesel from microalgae. Background technique [0002] Energy issues are not only related to my country's rapid economic growth and sustainable social development, but also to my country's national security and diplomatic strategies. In the situation of the straight-line growth of my country's oil imports and the soaring international oil prices, the importance of developing new energy alternatives to fossil energy is particularly highlighted. Due to the extensive use of fossil energy, it has also led to global environmental changes and a sharp reduction of fossil energy. The world has begun to focus on renewable energy including biomass energy. [0003] The United States is the first country to research biodiesel, and the demand for biodiesel is strong. The research on biodiesel production technology in the United States is not only leading the world, but also...

AI Technical Summary

Problems solved by technology

[0009] 3. There are many ways to prepare biodiesel by transesterification of animal and vegetable oils. Methods without catalysts such as subcritical and supercritical can simplify downstream processing steps, but require high equipment and high energy consumption, which is not suitable for current industrial production; Solid catalysts are also a research hotspot now, but most of them are in the stage of laboratory experiments. There are problems such as difficult synthesis, instability, and short catalytic life, and they still cannot be used on a large scale.

At present, there is no report on the patent of directly using microalgae methyl esterification one-step method to prepare biodiesel without extracting microalgae oil

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