Acetic Acid Recovery Using Membranes

The recovery of acetic acid from dilute aqueous streams is an important industrial separation that is both high cost and energy intensive when performed by conventional distillation technology. A need exists for more efficient, lower cost, simpler technology, such as membrane technology. However, the required separation performance, combined with the need for robust chemical and thermal stability of the membrane materials, makes the use of membrane technology for acetic acid recovery very challenging. In this project, perfluorinated polymer membranes will be used to separate the compressed acetic acid from the water vapor in a conventional distillation column. In Phase I, the perfluoropolymer membranes will be optimized, and bench-scale membrane modules will be used to separate water from hot aqueous acetic acid solutions. The data obtained will be used in a process simulation to determine the technical performance and economic feasibility of the proposed distillation-membrane process. In Phase II, a pilot system will be constructed to evaluate the performance of industrial-scale membrane modules, and a field test will be carried out using the pilot system. Commercial Applications and other Benefits as described by the awardee: If successful, the technology will allow acetic acid to be recovered from many aqueous process streams currently discharged or destroyed. The membrane-distillation process should lower energy costs by more than 60% compared to use of conventional distillation alone. Longer term, a successful distillation-membrane technology could be applied to commercial separations of other similar dilute aqueous streams