a co 2 Preparation method of hydrothermal liquefaction of furfural from agricultural and forestry waste under atmosphere

Abstract

The invention discloses a method for preparing agricultural and forestry waste hydrothermal liquefied furfural in a CO2 atmosphere, which comprises the following steps of: S1, collecting agriculturaland forestry waste, crushing and screening the agricultural and forestry waste, adding the agricultural and forestry waste into a hydrothermal reaction kettle, and mixing the agricultural and forestrywaste with deionized water to form a mixed solution with a mass-volume ratio of 1:15 to 1:5; S2, blowing the kettle body by using CO2, after exhausting the air in the reaction kettle, closing an airoutlet valve, filling 0-2Mpa CO2, sealing the reaction kettle, raising the temperature to 150-250 DEG C under stirring, and keeping the temperature for 10-50 minutes; S3, after the hydrothermal reaction kettle is cooled to room temperature, releasing pressure to collect gas, collecting solid-liquid mixture in the reaction kettle after reaction, and carrying out vacuum filtration separation to obtain a solid part and a liquid part; S4, extracting the liquid part by using an organic solvent, separating and filtering an organic phase, removing the organic solvent, and obtaining biological oil rich in furfural through rotary evaporation. CO2 is used as inert atmosphere, and proper parameters are selected to jointly improve the selectivity and yield of furfural.

Description

technical field [0001] The invention belongs to the technical field of biomass energy, and more specifically relates to a CO 2 Preparation method of hydrothermal liquefaction of furfural from agricultural and forestry waste under atmosphere. Background technique [0002] Furfural, also known as 2-furyl formaldehyde, is a series of natural precursors of furan-based chemicals and solvents. It has high application value and is widely used in organic synthesis, analytical reagents, raw material preparation of pharmaceuticals and industrial products, etc. At present, furfural preparation methods mainly include hydrolysis liquefaction, catalysis and pyrolysis of biomass and so on. Biomass is rich in hemicellulose, which in turn degrades into furfural. In the hydrolysis method, hemicellulose is hydrolyzed under the action of acid and water to generate xylose, and xylose undergoes isomerization and continuous dehydration reaction to generate furfural. Biomass pyrolysis refers to ...

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Problems solved by technology

[0004] 1. N is commonly used in the prior art 2 As an inert gas for the reaction, the yield of furfural usually needs to be further improved;

[0005] 2. The patent with the application number "201610692355.0" discloses a method for preparing furfural from camellia oleifera husks, and mentions the use of carbon dioxide as a weakly acidic gas catalyst, but the patent also uses catalyst additives to act together

There are many side reactions in the existing catalytic system, and these side reactions will reduce the selectivity of pentose to furfural, resulting in a large loss of furfural;

[0006] 3. In the prior art, the production of furfural per ton needs to consume 25 to 35 tons of water vapor, the reaction time is relatively long, and the use of steam as a heat source and extractant consumes a lot of energy and high cost; and the pyrolysis process has high energy consumption, The problem of high catalyst cost needs to be improved

[0007] 4. Using dilute acid as a catalyst is easy to corrode equipment, which requires expensive metal equipment maintenance costs and serious environmental pollution

And its separation and recycling are very difficult, and the dilute acid hydrolysis method will also lead to a large amount of acidic furfural wastewater, which is extremely difficult to treat

[0008] In short, the furfural industry is a typical industry with high energy consumption and heavy pollution. It has been reported that the furfural preparation method has a great effect on increasing the yield, reducing energy consumption, reducing wastewater discharge and slowing down equipment corrosion, but it still cannot completely solve the pollution problem. or cannot be applied due to high cost

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