Simulation for Optimization of a Filter Cake System

Abstract

The purpose of this project is to create a computational fluid dynamics (CFD) simulation of the cake filtration process for Agrilectric Research. Cake filtration is the process by which solid particulate is filtered out of a mixture of fluid and solid phases. As the mixture flows through the system, the particulate accumulates on a filter cloth to form a filter cake, which acts as an added filtering medium to the system. The results obtained from this project can be used to aid Agrilectric in the development of their experimental testing methods by providing the ability to measure and predict filtration properties and to experiment with different filter cake designs to improve filtration methods and performance, without reliance on empirical data. The work was completed using the Workbench platform with the Fluent solver from the Ansys Student software bundle. A 20 cm long, 10 cm diameter filter cell was modeled and meshed through Workbench and was imported into Fluent to conduct the simulation. The flow of a mixture of water and a particulate phase of rice hull ash (RHA) was simulated using the Eulerian multiphase model. This would show the movement of the RHA through the system and the accumulation of the particulate on a filter cloth over time. The filter cloth was modeled using a porous cell zone to mimic filtering properties. The simulated solution shows RHA flowing into the system and initially passing through the filter cloth. After some time, a packed layer of particulate forms across the width of the filter cloth that allows a filter cake to accumulate in the system. The results from the multiphase simulation prove that with more research and simulation development, the model can be improved to represent a realistic cake filtration system which can be used to supplement or to replace existing laboratory testing.