System and method for producing furol by using agricultural and forestry castoff

Abstract

The invention discloses a system and method to produce furfural with agricultural wastes, which is characterized by the following: choosing two-step method; comprising hydrolysis system and dehydration distilling system; setting the hydrolysis system as N grade hydrolysis autoclave with end-to-end; proceeding continuous hydrolysis for the agricultural wastes; generating pentose solution; setting the dehydration distilling system as dehydration distilling unit and dehydration reclaiming unit; dewatering and distilling for the pentose solution with the dehydration distilling unit; getting furfural steam; setting the dehydration reclaiming unit as at least one grade dewatering reactor; further-dewatering; generating furfural steam; sending into dehydration distilling tower; distilling continuously; sending the waste water from the dehydration reclaiming unit back to dehydration system; realizing zero discharge for waste water. This invention possesses high productivity, low energy consumption and warm reacting condition, which can be used as raw material to produce alcohol.

Description

System and method for producing furfural from agricultural and forestry waste technical field The invention belongs to the field of furfural production and preparation, and in particular relates to a system and method for producing furfural by utilizing agricultural and forestry waste. Background technique Furfural, also known as furan formaldehyde, has two double bonds and an aldehyde group on the furan ring. This unique chemical structure can make it undergo oxidation, hydrogenation, chlorination, nitration and condensation reactions to produce many chemical products. , so it is widely used in many production fields such as pesticides, medicines, petrochemicals, food additives, and casting. Furfural is produced from plant fibers rich in pentosans, such as corn cobs, bagasse, straw, corn stalks, cottonseed hulls, rice husks, etc. The principle is that pentosans in plant fibers are first hydrolyzed into pentosans sugar, and then dehydration of the pentose sugar to furfur...

AI Technical Summary

Problems solved by technology

(1) Only one reaction tank is used to carry out the dehydration reaction of pentose, and the conversion of pentose is incomplete;

(2) The acid solution in the furfural production process and the aqueous solution containing pentose sugars are sent back to the hydrolysis tank to participate in the reaction after adjusting the pH value and concentration, which fully shows that there are still unreacted substances after hydrolysis, dehydration and other steps. Pentose, so the conversion of pentose is not sufficient;

(3) In this patent document, the catalyst is disclosed in the circulation of volatile organic acids, but the circulation of the organic acids is only the acid circulation in the hydrolysis process of vegetable substances, but new inorganic substances are added in the dehydration process of pentose sugars. Acid, namely sulfuric acid, is used as a catalyst for the dehydration reaction. In this patent document, the treatment of sulfuric acid and wastewater after the reaction is not mentioned, so not all acids and wastewater in this patent are recycled.

This prior art only discloses the method for continuously hydrolyzing corn cob or bagasse to produce xylose, but does not disclose the process for producing furfural from corn cob or bagasse, which is not a complete two-step process for furfural production

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