Recovery Of Dilute Acetic Acid From Wastewater By Extraction

After compareing a variety of separation methods by searching through literature, this paper select complex extraction to separate and recover acetic acid from wasterwater which is discharged in the production process of furfural, because the method of complex extraction has a high capacity and high selectivity for dilute solution. Liquid-liquid equilibrium data at atmospheric pressure was determined for the extractant S100, the initial concentration of the acetic acid and temperature on extraction process were studied. The regeneration condition of extractant S100 was studied by the experiment of distilltion. RPC was uesd for the acetic acid complex extraction process, the affection of sieve material, vibration frequency, solvent volume ratio and two-phase flow on the extraction process were studied. Pulsed packed extraction column was uesd for the acetic acid complex extraction process, the affection of pulse intensity, pulse frequency, solvent volume ratio and two-phase flow on the extraction process were studied. RPC for pilotscale experiment was used to do the pilotscale experiment on acetic acid complex extraction process.The experimental results are as follows: (1) With the decrease of initial concentration of acetic acid, complex extraction distribution ratio is increase, indicating that the complex extraction on the extraction of dilute solution has great advantagesWith the increase of the extraction temperature, complex extraction distribution ratio is decrease, indicating that extraction process is an exothermic process. (2) After atmospheric distillation and vacuum distillation of the experiment, the final conditions of regeneration extractant S100 is at 120℃, 2.94kPa. (3) For RPC, the material of the sieve plate should be chosen the material which is not wet by the dispersed phase. Under experimental conditions, with the increase of vibration frequency, the solvent volume ratio and two-phase flow, the extraction rate and the theoretical stages are increase. (4) For the pulsed packed extraction column, with the increase of the pulse intensity and pulse frequency, extraction rate are first increase and then decrease, indicating extraction experiments should choose the appropriate pulse intensity and pulse frequency. With the increase of solvent ratiod, the extraction rate is increase, but the theory stages is decrease. With the increase of two-phase flow, the extraction rates and the theory stages are declined. (5) RPC for pilotscale experiment is used for acetic acid complex extraction process of the pilotscale experiment, after one test in a countercurrent extraction experiments, acetic acid extraction rate reache 98% to illustrate complex extractant S100 for acetic acid extraction is feasible.