CN104560409B - Method for direct preparation of biodiesel by utilizing microalgae ultrasonic-assisted ionic liquid composition - Google Patents

Abstract

The invention discloses a method for directly preparing biodiesel from a microalgae ultrasonic-assisted ionic liquid composition. The method comprises the following steps: a. After removing impurities, crushing and grinding the dried microalgae, passing through a 200-300 mesh sieve, taking Add the ionic liquid composition to the undersize, mix well, then add methanol, and react at 60-110°C for 1-5 hours under the condition of ultrasonic assistance; after the complete reaction, let stand and cool at room temperature for 1-1.5 hours, After the microalgae residue is removed by filtration, the filtrate is statically stratified; the upper layer solution is taken and subjected to vacuum distillation to obtain crude biodiesel. The method combines the dissolution and extraction performance of ionic liquids, catalytic performance and the cavitation effect of ultrasonic waves; the extraction of oil and the esterification of oil are combined into one, the operation is simple and convenient, the process steps are greatly simplified, and biodiesel can be prepared quickly, thereby greatly Improve production efficiency, reduce production cost, and provide a new method for industrial scale production of biodiesel.

Description

Direct preparation of biodiesel from a microalgae ultrasonic-assisted ionic liquid composition method

Technical field:

The invention relates to the field of biochemical industry, in particular to a method for directly preparing biodiesel from an ionic liquid composition assisted by microalgae ultrasonic waves.

Background technique:

The dwindling oil resources lead to energy shortages and soaring oil prices, making people pay more and more attention to finding its substitutes. Biodiesel not only has the same combustion performance as petroleum diesel, but also has the advantages of environmental friendliness and renewable resources. It is an ideal fuel to replace petroleum diesel, and has attracted much attention in recent years.

At present, foreign countries mainly use rapeseed oil and soybean oil as raw materials, and use strong acid or strong base catalysts to catalyze biodiesel production. However, the official investigation of the United Nations declared that the use of a large number of food crops in the United States and Europe to produce biofuels is an important cause of the global food crisis. Therefore, actively looking for new biomass raw materials to alleviate the current food and energy crisis has become a high concern for all countries in the world The problem. Among many biomasses, algae have the characteristics of high photosynthetic efficiency, strong environmental adaptability, short growth cycle and high biological yield, so algae are good materials for preparing biomass energy.

The traditional microalgae biodiesel production process is mainly divided into two steps: first, the oil is extracted from the microalgae raw material with an organic solvent; then, the oil is sent to a reaction vessel for esterification by strong acid or alkali.

Invention content:

However, the traditional process of using microalgae to prepare biodiesel also has problems to be solved:

First of all, due to the thick cell wall of most oil-containing microalgae, it is difficult for the oil in the cell to seep out of the cell wall during conventional organic solvent extraction. Solvent extraction of oil takes a long time and requires a large amount of organic extractant, which increases the difficulty of separation The extraction efficiency is low; in addition, the microalgae extracted with an organic solvent need to distill off the organic solvent to obtain oil.

Secondly, the traditional process of using strong acid or strong base to prepare biodiesel has the disadvantages of large alcohol consumption, difficult recovery of the product, and large environmental pollution. The preparation of biodiesel by enzymatic method is often carried out in the reaction medium of organic solvents. Strong polar organic solvents will deprive the necessary water in the microenvironment of the enzyme surface, seriously affect the activity of the enzyme, and reduce the service life of the enzyme.

In view of the above technical problems to be solved, if the two parts of microalgae oil extraction and transesterification reaction can be coupled into one unit, the process route can be shortened, and a reaction system that can effectively improve the extraction rate and conversion efficiency of microalgae oil can be found to improve the efficiency of esterification. The amount of synthesis has certain significance for the industrial production of microalgae biodiesel.

The purpose of the present invention is to provide a method for directly preparing biodiesel from microalgae ultrasonic-assisted ionic liquid composition.

The present invention is achieved through the following technical solutions:

A method for directly preparing biodiesel from a microalgae ultrasonic-assisted ionic liquid composition, the method comprising the following steps:

a. After removing impurities, pulverizing and grinding the dried microalgae, pass through a 200-300 mesh sieve, take the sieve, add the ionic liquid composition, put it into the extraction-reaction kettle, mix well, then add methanol, Under auxiliary conditions, react at 60-110°C for 1-5 hours; the ionic liquid composition is composed of component A and component B, wherein the mass fraction of component A is 90%-98%, and component A is selected from From 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) or 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), component B is selected from 1-butyl- 3-methylmorpholine salt [Hnmm] Im or 1-hexyl-3-methylimidazolium bisulfate ([HMIM]HSO ₄ ); the mass ratio of the microalgae undersize and the composite ionic liquid composition is 1:10～1:40; the molar ratio of methanol to microalgae oil is 6:1;

b. After the reaction is complete, the material is allowed to stand and cool at room temperature for 1-1.5 hours, after filtering to remove the microalgae residue, the filtrate is statically stratified; the upper layer solution is subjected to vacuum distillation to obtain crude biodiesel.

The microalgae are selected from Chlorella or Scenedesmus.

The ultrasonic described in step a, the ultrasonic power is 240W.

The lower layer solution obtained after static layering in step b is distilled to remove methanol and glycerin, and the ionic liquid is recovered, and the ionic liquid can be recycled.

The beneficial effects of the present invention are as follows:

(1) The biggest feature of this application is that the whole reaction is "one-step completion". The extraction and the esterification or transesterification process of oil are combined into one, which avoids the extraction and refining of oil and greatly simplifies the process steps.

(2) The ionic liquid composition of this application is not only used to catalyze the production of biodiesel from microalgae oil, but also has the function of extracting "microalgae oil". The ultrasonic wave of this application is not only used to assist in catalyzing microalgae oil For the production of biodiesel, it also has the function of assisting in the extraction of "microalgae oil", so that the extraction of microalgae oil is realized, and the extracted microalgae oil is directly converted into biodiesel.

In conclusion, the present invention provides a new method for extracting oil from microalgae and catalyzing the preparation of biodiesel by combining ultrasonic waves with a composite ionic liquid composition. This method utilizes the strong solubility of ionic liquids to microalgal cell walls and high catalytic activity to microalgal oils, combined with the anti-permeability and crushing effect of ultrasonic waves on microalgal cell membranes and the action of ultrasonic vibration to accelerate the movement of ionic liquids and algae powder, increasing the concentration of ionic liquids. and algae flour collide with each other, thereby improving the oil extraction rate and oil conversion rate of microalgae. This method combines the advantages of ionic liquid dissolution and extraction performance, catalytic performance and ultrasonic cavitation effect; it combines the oil extraction and oil esterification or transesterification process into one, with ingenious design and simple and convenient operation. The extraction and refining of oil is avoided, the process steps are greatly simplified, and biodiesel can be prepared quickly, thereby greatly improving production efficiency and reducing production costs, and providing a new method for industrial and large-scale production of biodiesel.

Description of drawings:

Fig. 1 is a schematic diagram of the process flow of the present invention.

detailed description:

The following is a further description of the present invention, rather than a limitation of the present invention.

Example 1:

The dried Scenedesmus was removed, pulverized and ground, and passed through a 200-mesh sieve; 5 grams of sieves were taken, and 50 grams of ionic liquid composition was added (the ionic liquid composition was composed of component A and component B mixed, wherein Component A mass fraction is 90%, component A is 1-butyl-3-methylimidazolium chloride salt ([BMIM]Cl), component B is 1-butyl-3-methylmorpholine salt [Hnmm ] Im) mixed uniformly in the extraction-reactor, then add methanol (the mol ratio of methanol and microalgae oil is 6:1), on the ultrasonic synthesis extraction instrument, set the reaction temperature to be 70°C, and the ultrasonic power is 240W, Start the reaction in a water bath. After reacting for 1 hour, let it stand and cool at room temperature for 1 hour, filter the algae powder, transfer the filtrate into a separatory funnel, and after standing to separate layers, take the upper solution and carry out vacuum distillation to obtain crude biodiesel. 0.129 grams; the lower layer is distilled under normal pressure and under reduced pressure to remove methanol and glycerol, and reclaim the ionic liquid, which can be recycled.

Example 2

The dried Scenedesmus was removed, pulverized and ground, and passed through a 300-mesh sieve; 5 grams of sieves were taken, and 100 grams of ionic liquid composition was added (the ionic liquid composition was composed of component A and component B mixed, wherein Component A mass fraction is 95%, component A is 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), component B is 1-hexyl-3-methylimidazolium bisulfate ( [HMIM]HSO ₄ )) was mixed uniformly in the extraction-reaction kettle, and then methanol was added (the molar ratio of methanol to microalgae oil was 6:1). The power is 240W, start the water bath reaction, after 2 hours of reaction, let it stand and cool at room temperature for 1 hour, filter the algae powder, transfer the filtrate into the separatory funnel, after standing for stratification, take the upper layer solution and carry out vacuum distillation, that is 0.158 g of crude biodiesel was obtained; the lower layer was distilled under normal pressure and reduced pressure to remove methanol and glycerol, and the ionic liquid was recovered, and the ionic liquid could be recycled.

Example 3

Remove impurities from the dried chlorella, crush and grind it and pass through a 200-mesh sieve; take 5 grams of sieved material, add 150 grams of ionic liquid composition (the ionic liquid composition is composed of component A and component B mixed, The mass fraction of component A is 95%, component A is 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), and component B is 1-butyl-3-methylmorpholine [Hnmm] Im) was mixed uniformly in the extraction-reactor, then methanol was added (the mol ratio of methanol to microalgae oil was 6:1), and on the ultrasonic synthesis extraction instrument, the set reaction temperature was 90°C, and the ultrasonic power was 240W, start the water bath reaction, after 3 hours of reaction, let it stand and cool at room temperature for 1 hour, filter the algae powder, transfer the filtrate into a separatory funnel, after standing for stratification, take the upper solution and carry out vacuum distillation to obtain biological 0.197 g of crude diesel oil; the lower layer was distilled under normal pressure and reduced pressure to remove methanol and glycerin, and the ionic liquid was recovered, and the ionic liquid could be recycled.

Example 4

The dried chlorella is removed from impurities, pulverized and ground and passed through a 300-mesh sieve; get 5 grams and 200 grams of the composite ionic liquid composition (the ionic liquid composition is composed of component A and component B, wherein component A mass fraction is 98%, component A is 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), component B is 1-hexyl-3-methylimidazolium bisulfate ([ HMIM]HSO ₄ )) Mix well in the extraction-reaction kettle, then add methanol (the molar ratio of methanol to microalgae oil is 6:1), set the reaction temperature to 100°C on the ultrasonic synthesis extractor, and the ultrasonic power 240W, start the water bath reaction, after 4 hours of reaction, let stand and cool at room temperature for 1 hour, filter the algae powder, transfer the filtrate into a separatory funnel, after standing for layers, take the upper solution and carry out vacuum distillation to obtain 0.199 g of biodiesel crude product; the lower layer is distilled under normal pressure and reduced pressure to remove methanol and glycerin, and recover the ionic liquid, which can be recycled.

Claims (2)

1. a kind of method that microalgae ultrasonic assistant ionic liquid compositions directly prepare biodiesel, it is characterised in that the party Method is comprised the following steps：

A, will dry microalgae removal of impurities, crushing, grinding after, cross 200~300 mesh sieves, extracting screen underflow, add ionic liquid combination Thing, is fitted into extraction-reactor, mixes, and is subsequently adding methyl alcohol, and under conditions of ultrasonic wave added, 60~110 DEG C of reactions 1~5 are small When；The ionic liquid compositions, are made up of component A and component B mixing, and wherein component A mass fractions are 90%~98%, group A is divided to be selected from 1- butyl -3- methylimidazole villaumites ([BMIM] Cl) or 1- pi-allyl -3- methylimidazole villaumites ([AMIM] Cl), group B is divided to be selected from 1- butyl -3- methyl morpholines salt [Hnmm] Im or 1- base -3- methylimidazolium hydrogen sulphates salt ([HMIM] HSO₄)；Institute It is 1 that microalgae screenings is stated with the mass ratio of compound ion liquid composition：10~1：40；The methyl alcohol and microalgae grease mole Than being 6：1；Described microalgae is selected from chlorella or grid algae；

B, reaction completely after material, at room temperature stand cooling 1-1.5 hour through elimination remove microalgae residue after, static point of filtrate Layer；Upper solution carries out vacuum distillation and obtains coarse biodiesel；Lower floor's solution reclaims ionic liquid through distillation for removing methanol and glycerine Body, the ionic liquid is recycled.

2. the method that microalgae ultrasonic assistant ionic liquid compositions according to claim 1 directly prepare biodiesel, Characterized in that, ultrasound described in step a, ultrasonic power is 240W.