Excel for Chemical Engineering

Excel for Chemical Engineering

Material balance for a non-reactive system:

Material balance is based on the law of conservation of mass that states that mass can neither be created nor destroyed but can undergo phase and chemical changes. In precise, 

Material Input + Material Generated = Material Output + material Accumulated in the system + Material consumed.

Mass balance for a non-reactive system can be generally expressed as Input = Output + Accumulation where generation and consumption are zero. The above equation becomes Input = Output for steady-state processes where the accumulation tends to zero. Identifying the tie element, the component that enters and leaves the system without any change can be useful to solve the equations surrounding the system. Mass balance is generally carried out in 2 levels: Overall balance and Component balance. Overall balance is the material balance for the entire system under study while the component balance is carried out for an individual component in the system. The following example will be useful in understanding.



1.    Calculate the Degrees of Freedom to check whether the given information is enough to solve the problem and can the problem be solved. If DOF is equal to 0 then the problem can be proceeded to solve.



2.   Frame the component and overall balance equations.

3.   Create a Matrix A using the component balance equations and determine its determinant value.



4.   If only the determinant value is 0 the square matrix has an inverse.

5.   Now find the inverse which can be multiplied with matrix B to determine the unknowns, W, S, and N.





6.   Multiply the inverse and Matrix B to determine the unknowns.








 

 

Reference:

Stoichiometry and Process Calculations by K.V. Narayanan and B. Lakshmikutty.

 


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