Economic feasibility study of citrate recovery by electrodialysis

In this work, the optimal operating conditions (pH and current density) for citric acid recovery fro aqueous solutions via electrodialysis (ED) were determined by balancing the investment and maintenance costs against the energy costs. By referring to a series of industrial-scale ED plants, the specific recovery costs (c(o)) were found to be dependent on plant capacity (Q(p)), current density (j) and specific costs of solute (c(s)) and electric energy (c(ee)). For a plant size of 2500 metric tons per year fed with aqueous solutions containing 100 gi dm(3) of citric acid at pH ranging from 3 to 7, and for c(ee) = Lit 100/kWh and c(s) = Lit 2000/kg, the ED recovery of mono-, di-, or tri-sodium citrates would cost Lit 1900/kg, Lit 74 or Lit 565/kg, respectively thus showing that critic acid can be more economically separated from clarified fermentation broths by ED once converted into the tri-sodium salt. (C) 1998 Elsevier Science Limited. All rights reserved.