Influence of pre-dewatering on the success of cake washing

Cake washing is one key challenge after filtration. It is used to improve the product quality of filter cakes. Many studies deal with washing of saturated filter cakes and are used as the basis for cake washing models. However, to avoid mixing of supernatants (e.g. suspension liquid and wash liquid) on the cake surface during production processes, the cake is pre-dewatered and thus the pores are undersaturated. This paper demonstrates the influence of different start saturations (different pre-dewatering times) on the displacement regime of a washing curve compared to washing saturated filter cakes. An increase in saturation (filling) also takes place at the beginning of the washing of undersaturated filter cakes. A new filling regime located at the beginning of the washing process is clearly defined before the known displacement regime. The extent of the filling regime depends mainly on the initial saturation before washing process.

Automated summary

This study investigates the influence of different start saturations on the displacement regime of washing curve in cake washing of undersaturated filter cakes, and finds that an increase in saturation happens at the beginning of the washing process.