# multiple mixed flow reactor system

This has to do with the connection of reactor for operation in a plant. They can be connected in series or parallel.

Considering N number of reactors connected in series; with fractional conversion of Y1-Yn

$\frac{V}{F}=\sum _{i}^{N}\frac{Vi}{Fi}$

For total volume of reactors in series is equal to the conversion of a single plug flow reactor of volume(V). When a system is a combination of series and parallel connection it can be treated as a single plug flow. This is done by adding the volume of individual units in each branch; so as to have the same conversion.

Example: The reactor setup below consists of four plug flow reactors in two parallel branches. Branches reactor of volume 30 liters followed by a reactor of volume 20 liters. Branch B has a reactor of volume 40 liters followed by a reactor of volume 60 liters. What fraction of the feed should go to Branch B?

Reactor 1 and 2 are in series and 3 and 4 in branch B are in series while the two branches are in parallel.

VA=30 +20 = 50 liters

VB=40 +60 = 100 liters

FA/FB = 50/100 = 0.5

Therefore half of the feed will be fed into the branch B.

## SIZE MIXED FLOW IN SERIES

In general, the concentration of reactants in reaction decreases gradually as the reaction proceeds. While the concentration of products increase. In a plug flow, the same attribute applies. But in a mixed flow reactor, the concentration of the reactant decreases immediately to a low value. Reason being that a plug flow reactor is more efficient than mixed flow reactor. This is for reaction whose rate increase with reactant concentration. (i.e irreversible reactions). Now, when there is a series connection of mixed flow reactors with equal concentration of reactant. As the reactants move from one reactor to another as reaction process; they attain the state or behavior of a plug flow reactor.

For second order reaction: Here, much of the evaluation of the performance equation is done using a chart. But, it should be noted that; there will not be excess reactant in the system.