9
CHAPTER
Selected Definitions FUtratlon: It is defined as a solid liquid separation process in which solids are separated from suspension by passing through a porous medium that accumulate the solids, but allows the passage of fluids.
Slurry: It is the suspension of solid and liquid which is to be filtered. FUter medium: It is the porous medium used to filter the solution. FUter cake: It is defined as the accumulated solids on filter medium. Filtrate: It is the clear liquid which pass through the filter, Clariftcatlon: It is the separation process in which the amount of solid in liquid is not more than 1 % w/v. Rate of mtratlon: It is defined as volume of filtrate collected in unit time. Poiseuille's equation" This equation states that the flow of the filtrate under pressure through capillaries is laminar PermeabUity: It is defmed as flow rate of liquid having unit viscosity across unit area of cake and unit thickness under pressure difference of unity.
Filter aids: These are inert powders added to the liquid be filtered and increase the porosity and cake permeability. Surface mtration: It is the process of removal of material suspended in a liquid by means of sieving. Membrane Filtration: It is a separation process that uses a semipermeable membrane. Bubble point pressure: It is the minimum pressure which is required to force the liquid out of the capillary.
9.1 INTRODUCTION Filtration can be defined as a solid liquid separation process in which solids are separated from suspension by passing through a porous medium that accumulate the solids, but allows the passage of fluids. The suspension of solid and liquid which is to be filtered is known as slurry. The porous medium used to filter the solution is known as filter medium. The accumulated solids referred as filter cake. The clear liquid passing through the filter is filtrate. The term clarification is used when amount of solid in liquid is not more than 1 % w/v. Rate of filtration is defmed as volume of filtrate collected in unit time.