Question

Write the general mass balance equations for systems with and without transformation.

Answer 1

A mass balance is also called material balance. It is an application of conservation of mass to the analysis of physical systems. The law of conservation of mass states that mass can neither be created nor be destroyed ,but may undergo phase changes i.e transfer from one phase to another & also chemical changes. It is used in engineering & environmantal analysis. eg: it is used to design chemical reactors, to analyse alternative processess to produce chemicals.In an industrial process, material balance provides an exact accounting of all the materials that enter & leave & of the changes in the inventory of the material in the course of a given interval of time of operation.

Material balance eq. for systems with & or without transformation is

(material input to the system) - (material output from the system) +( material generation within the system) - (material consumption within the system) =( accumulation of material within the system) .

Mass balance for a system without a chemical reaction is

Input = Output + accumulatiom , where generation & consumption terms are zero.