Recovery and purification of acetic acid from aqueous mixtures by simulated moving bed adsorption with methanol and water as desorbents

Abstract

The objective of this work is to study the recovery of acetic acid from aqueous mixtures by adsorption using a commercial polyvinylpyridine (PVP) resin (Reillex® 425) as adsorbent, and methanol or water as desorbents. A theoretical model has been developed to describe the adsorption/desorption dynamics of acetic acid from aqueous mixtures in a fixed bed of the commercial resin. The model has been used to design and optimize a cyclic process based on simulated moving bed (SMB) technology for the recovery of acetic acid from a 10% w/w acetic acid/water mixture. The Triangle Theory and the volume separation method have been used, and an acetic acid with recovery ≥95% is obtained, and purity ≥99%. Productivities of 47.3 kg msolid−3 h−1 and 52.0 kg msolid−3 h−1, with desorbent consumptions of 0.0316 m3 kg−1 and 0.0205 m3 kg−1 have been achieved with methanol and water as desorbents, respectively. The recovery process of methanol from extract and raffinate streams has been simulated with Aspenplus®, calculating the energy requirement (0.0135 MJ/kgacetic acid).