Monitoring the Growth and Removal of Cake Fouling Using Automated micro-Fluid Dynamic Gauging

A wide variety of industrial processes such as water purification, fractionation, solids removal or recovery, and dewatering can be performed using synthetic membrane filtrations. The performance of these membrane processes deteriorate over time due to the deposition of unwanted fouling layers upon, or within, the membrane, causing declining permeate flux, increased operational cost, and shortened membrane life. In this research, an Automated micro-Fluid Dynamic Gauging (AmFDG) technique has been designed, constructed and used to study cake fouling during cross-flow microfiltration of ballotini and LignoboostTM softwood Kraft lignin suspensions through mixed cellulose ester membranes of 0.2 micron nominal pore size. Thickness of the cake layers were measured in situ and in real time during fouling. AmFDG was also used to perform strength tests on preformed cakes, by imposing controlled fluid shear stresses to the layer and measuring the thickness following deformation. Ballotini-Lignin mixtures were found to produce considerably thicker layers compared with lignin only fouling layers. Interestingly, the addition of ballotini reduced the lignin fouling layers’ strength significantly.