Continuous stirred tank reactor (CSTR),

The continuous stirred tank reactor (CSTR) is one of the electronic apparatus used in the laboratory to investigate reactions and conductivity of the reactants and products formed as the reaction proceed. It is a common apparatus or model used in Chemical Engineering. Continuous stirred tank reactor is design be serve the purpose of a batch a reactor having an impeller or a mixing device to provide a homogeneous mixing during reaction. In chemical engineering discipline, continuous stirred tank reactor is often referred to as an idealized agitator tank reactor used in modeling operations of variables required to attain a specific output.

Continuous stirred tank reactor is an open system, materials are free to enter and exit the system, it operates on a steady state where the contents of the tank are independent of time. Reactants are continuously fed in the reactor while products are also produce continuously. Due to the homogeneous mixture in the reactor, the content has uniform properties such as density and temperature throughout system.

The mechanism of a continuous stirred tank reactor is often approximately as a modeled ideal reactor, therefore the calculations carried are assumed to be in perfect mixing of the solution in the tank. In a perfectly mixed reactor, the composition of the output is equal to the output materials unlike the feed (input=output), which is function of rate of reaction (chemical kinetics) and the residence time, this approximation is valid in Engineering purposes ( residence time is the average time a particular quantity of reagent spends inside the reactor). The rate of reaction in the reactor is dependent on the concentration of the reactant which is displayed as the conductivity of the reactants or products on the CSTR and rate constant. The Arrhenius equation can be used to determine the rate constant which is function of temperature. The rate of reaction increases as temperature increased.



image of a continuous stirred tank reactor

Continuous stirred tank reactor consist of a constant volume tank and a string system that mix reactant together. It has lid to introduce the feed and the exit pipes are present to remove products. It has a stirring blade also called ‘agitator’ (it is revolving device) which are used to mix the reactants. CSTR can also function as loop reactor when a fluid heated and pressurized is introduced in the system to facilitate the stirring. This allows for higher heat a d mass transfer.

Applications of CSTR

Continuous stirred tank reactor has many applications in engineering practices, such as water treatment processes and industrial processing. It is also used in the pharmaceutical industry as a loop reactor, in biological sciences, it is used in fermentation process, where a biological catalyst is needed for product conversion, here microbes are introduce  to break larger molecules in smaller ones. Fermentation is seen in the area of brewing.

Continuous stirred tank reactor helps to facilitate dilution rate which makes resistant to PH volatile fatty acid waste.




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