Method for recycling butyric acid by treating butanol and octanol waste lye

Abstract

The invention relates to a method for recycling butyric acid by treating butanol and octanol waste lye. The method comprises the following steps: acidizing butanol and octanol lye through inorganic acid, and recycling an organic phase in the upper layer; absorbing acidic water in the lower layer through a resin tower; when the pH of resin tower acidic outlet water subjected to adsorption treatment is neutralized to be 6 to 9 through lye, and feeding the resin tower acidic outlet water into a sewage treatment plant to be treated or utilizing the resin tower acidic outlet water as acid for neutralization; when resin adsorption is saturated, adsorption is stopped, performing desorption regeneration treatment on the resin, and recycling butyric acid; and performing desorption by virtue of a desorbent flowing back to the resin tower, feeding a desorption solution into a rectifying tower to be subjected to rectification treatment, so as to separate desorbent and coarse butyric acid, recycling the desorbent, and recycling the coarse which serves as a product. The method has the advantages that the CODCr (Chemical Oxygen Demand) of the butanol and octanol waste lye is reduced to lower than 300 mg / L, the total removal rate of CODCr reaches more than 99.0 percent, and treated outlet water can be used as acid for neutralization or can be directly discharged to the sewage treatment plant so as to be subjected to biochemical treatment after being neutralized through alkali, so as to realize up-to-standard release.

Description

technical field [0001] The invention relates to a method for recovering butyric acid from waste lye of butanol and octanol. Background technique [0002] my country's existing butanol production process is mainly propylene oxo synthesis method. In the method, propylene and synthesis gas are used as raw materials to synthesize butyraldehyde, and then the butyraldehyde is condensed under the catalysis of 2% sodium hydroxide to generate octenal. Butyraldehyde and octenal are finally hydrogenated to butanol and octanol. While butyraldehyde is condensed to form octenal, Cannizzaro reaction (Cannizzaro Reaction) also occurs at the same time, and the reaction formulas are as follows: [0003] [0004] 2CH 3 CH 2 CH 2 CHO+NaOH→CH 3 CH 2 CH 2 COONa+CH 3 CH 2 CH 2 OH (2) [0005] As can be seen from the above reaction formula, on the one hand, n-butyraldehyde is condensed to generate octenal while generating equimolar water; on the other hand, sodium hydroxide is consum...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that COD Cr Lower removal rate

[0010] Chinese patent CN1530334A adopts acidification heat separation technology to treat octanol waste lye. This method acidifies the waste lye to pH less than 4.5, heats the emulsion formed after acidification to a temperature of 95-100°C, and heats it for less than 0.5h, then statically Set the layers to form the oil-water two-phase. By setting the outlet height of the oil-water two-phase, the two phases can be separated automatically, and the organic phase can be recycled. This method does not need to add an extraction agent, but the COD Cr The removal rate is only about 50%, and the energy consumption is high

However, this process has high infrastructure investment, complex operating conditions, and high operating costs. It is still in the experimental stage and there are no reports of industrial applications.

[0016] Comprehensively analyzing the gains and losses of the above methods, it can be seen that although there are many recycling methods for octanol waste lye at present, and each has its own characteristics, it is still impossible to find a treatment method that is both environmentally friendly and economically beneficial.

Although the acidification method is the simplest and most economical and effective method for removing oily substances in spent octanol lye, it is difficult to recover the high value-added butyric acid in spent lye, and the existing extraction technology is also difficult to achieve the desired effect

And although concentration method and rectification method effect are better, processing cost is high, and the sodium butyrate quality that concentration method reclaims is poor simultaneously, is difficult to purify; Rectification method can only obtain the butyric acid that water content is about 81.4% (mass content) Azeotropic liquid, there is no relevant technical report on further concentration and purification

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