Energy-Saving Recovery of Acetone, Butanol, and Ethanol from a Prefractionator by the Salting-Out Method

Abstract

Thirty compounds including salts, saccharides, and alkalies have been investigated as possible salting-out agents to recover (acetone + butanol + ethanol) (ABE) from a prefractionator. The most promising salt is potassium carbonate. The mechanisms of salting-out by potassium carbonate are summarized as hydration and hydrogen-bond breaking. The thermodynamic study of salting-out by potassium carbonate has been investigated and shows that the salting-out process is endothermic and a process of entropy increment. The extractant of saturated potassium carbonate solution should be double that of the sketchy ABE solution. When the salting-out process is performed at 333.15 K instead of 298.15 K, equilibrium time is shortened from 9 to 3 min. Energy demand in an industrial application shows that salting-out produces 25.13 %, even 35.42 % less energy consumption than that of the conventional distillation process.

Salting-out effect of tripotassium phosphate on the liquid–liquid equilibria of the (water+acetone+1-butanol+ethanol) system and the salting-out recovery

“…Another salting-out method is to recover acetone, 1-butanol and ethanol from aprefractionator.More than thirty compounds were investigated to recover ABE from a prefractionatorat our previous work [17].The salting-out of ABE with the K 2 CO 3 solution had been reported in our paper.But the salting-out factor of 4/2 makes the (salting-out + distillation) method less energy-saving. The salting-outfactor isdefined as the volume of asalt solution divided by thatof the sketchy ABE solution (volume ratio).…”

“…4 , whichshowed much better salting-out performances than K 2 CO 3[17].K3 PO 4 showed great salting-out effects due to a large amountof ionized cations and hydrolytichydroxyl ions. The water contentof the organic phase decreased from 60.00 % to 7.11 % after the saturated addition of K 3 PO 4 ﹒3H 2 O at 298.15 K.The hydration of K 3 PO 4 relied heavily on the concentration of K 3 PO 4 .…”

Salting‐out of bio‐based 2,3‐butanediol from aqueous solutions

“…The salting-out technique was used to promote the liquid-liquid phase splitting. Many salts can cause liquid-liquid phase splits of solvent-water systems, such as the (acetone + 1-butanol + ethanol + water) system, 18 and the (acetone + water) system. 19 2,3-BD from the fermentation broth was also confirmed to be salted out, 20,21 but the 2,3-BD fermentation broth should be concentrated first.…”

Integrated in situ gas stripping–salting-out process for high-titer acetone–butanol–ethanol production from sweet sorghum bagasse

“…K 4 P 2 O 7 and K 2 HPO 4 behaved higher solubility accompany with the increase of temperature. Besides, the different salt concentrations also have a significant effect on the liquid–liquid equilibrium [ 27 ], and further affected the separation behaviors [ 26 – 29 ]. The saturated K 4 P 2 O 7 and K 2 HPO 4 solutions at different temperatures were added into the gas stripping condensate for the second-stage ABE separation, respectively.…”