Analysis of the Copesul Water-Oil Separation System

Abstract

This paper presents an overview of the water-oil separation system at COPESUL (Companhia Petroquímica do Sul). The design and operation of the system are discussed, and possible changes to be implemented to keep the oil and grease content of the effluent within the limits acceptable for its admission to SITEL (the integrated system of liquid effluent treatment of the South Petrochemical Complex). Since the start of operation, the system chosen, which includes a pre-separator and tiltable plate interceptor (TPI) water-oil separator, has experienced problems. The effluent generated has frequently had an oil and grease content above the limit set for acceptance by SITEL. The situation was investigated, and it was found that the problem was due to the following: operational conditions were different to the design conditions; oil with a density higher than water was present; there were deficiencies in the maintenance and cleaning systems. Various options were studied to eliminate these problems, and priority was given to increasing the capacity of the separation system, segregating the oil with a density higher than water at its source, and increasing the frequency of system maintenance. It was thought that these measures would result in an effluent oil and grease content less than 100 mg/l, and that the separation system would operate with greater flexibility.