Conceptual design of a treatment process for centrifugal mother liquor wastewater in the PVC industry

Abstract

The centrifugal mother liquor (CML) discharged by polymer enterprises is a typical refractory organic wastewater with a variety of pollutants. This paper proposes a novel homogeneous and heterogeneous mixed Fenton oxidation strategy for the degradation of phenol and other organic compounds in CML. First, two promising CML treatment schemes are selected from six alternatives. Second, with the minimal equipment investment cost as object, a better CML treatment scheme is selected from these two alternatives using reactor network synthesis method. This optimal scheme is further modeled and simulated by Aspen Plus, and the effect of Fe2+ and H2O2 flowrate on organic compound removal rate is studied by sensitivity analysis. The removal rate of organic compound is found increasing from 71 % to 82.6 % under the optimal flowrate of Fe2+ and H2O2. Finally, the importance of each variable in CML treatment process is evaluated based on mutual information. Three variables including the temperature of homogeneous reactor, the liquid level of homogeneous reactor, and the temperature of heterogeneous reactor are selected as key variables in the stability control study by Aspen Dynamics. The dynamic simulation results prove that the CML treatment process has high stability in the face of disturbances.