Experimental and numerical failure analysis of a rotary vacuum disc lime filter - Part 1: Fluid flow study of filtration process

Waldemar Cieslakiewicz

University of Johannesburg

Daniel Madyira

Marcos Roberto Rodrigues

Wilfrid Grimm

Dewald Scholtz

Abstract

The mechanical separation of solids from liquids (filtration) is a critical process in many chemical process industries. The rotary drum filter can be considered a work-horse device which is one of the oldest filtration devices that has been used for centuries. Its reliability is affected by several process parameters resulting in reduced life and poor separation effectiveness. Common problems include breakage of the filtration medium, wear of filtration holes and breakage of the backing plates. In this work a study is conducted to understand the causes of significant wear exhibited in a single rotary  disc vacuum filter to understand the process parameters that led to this failure. The process parameters were recorded and used to validate a CFD model, which in turn was utilised to conduct a parametric study of the systems. The whole study comprises two parts. The first one presents the numerical and experimental analysis of the fluid (water and slurry) flow in the filter, the second one focuses on the numerical and experimental mechanical evaluation of drum filter membrane material.

Keywords:

disc vacuum filter, cake formation, cake washing, cake drying, cake discharge, disc wear