Chemical process industries convert raw materials into useful products. Acids, among other chemicals, are used in many industries as reactants, solvents and also as catalysts in a few instances as well. Resulting streams are dilute, from which the acids must be recovered. For recovery, many technologies can be used by which acids can be regained as such or can be converted into other value-added products like esters. Membrane processes and biological
processes are being researched academically and practiced industrially. These have their own advantages and disadvantages in view of conversion, energy consumption etc. These are not always advantageous and hence an alternate process technology is necessary like reactive separation (RS). RS is advantageous especially when the acid is to be converted to other useful products by reaction, due to additional advantages or because no other technology is well suited or due to cost considerations alone. Conventional process technologies use the reactor configuration followed by the subsequent separation sequence. This approach can sometimes suffer from lesser conversion, difficulties in separation etc. To overcome these problems, RS has an edge over other processes in terms of the recovery of the useful compounds. Reactive distillation (RD), reactive extraction (RE) and reactive chromatography (RC) are the separation technologies that can be useful for acid recovery in an economically feasible way. This review covers the various processes of acid recovery along with the recent work in the field of reactive separations.
Sharma MM, Mahajani SM, Ind. applications of reactive distillation (A review), in Reactive Distillation by Sundmacher K.Kienle A, 1st Ed., Wiley VCH, Germany, 2003
Deshmukh KS, Gyani VC, Mahajani SM, Esterification of Butyl Cellosolve with Acetic Acid using Ion Exchange Resin in Fixed Bed Chromatographic Reactors, http://www.bepress.com/ijcre/vol7/A2/(28/01/2009).
Kumar S, Gupta K, Babu BV, Proceedings of Annual Meeting of AIChE, (Gaylord Opryland Hotel) Nashville USA, 2009