Home » About GATE » GATE study materials » Chemical Engineering » SINGLE AND MULTIPLE REACTIONS IN IDEAL REACTORS


The chemical reactors are the only ones that have the capability of generating single and multiple reactors. Here ideal reactors are going to be concerned.

There are many types of reactors used in chemical engineering. However, in this study, the ideal reactors are going to be considered to test the single reaction in chemical form as well as multiple reactions. This is because, in reality, the main reaction is always accompanied by other undesired reactions. These are the parallel Reactions that give the desired reaction as well as the undesired one. In Chemical Engineering this is one of the major issues. Chemical Engineering techniques deal with the undesired reactions to minimize them. Chemical reactors in chemical plants are hence calibrated to suit the purpose and these are going to be explored in this study. 


Ideal reactors 

Ideal reactors are reactors that enable researchers or chemical engineers can know the exact value of the chemical reactants. This is different from the other types of reactors such as the technical reactors, the real reactors, and the natural reactors that enable the researchers and chemical engineers to see the reactants only in an approximate value. Ideal reactors can process chemical reactions, biochemical reactions as well as physical reactions efficiently and is one of the most used reactor types in the world today. However, an ideal reactor exists only in theory and no reactor is an ideal reactor. The term “ideal reactor” in the field of Chemical engineering is only used to calculate the exact value of chemical reactions and variables of reactants. This is to say that an ideal reactor is a simulation that is done by the engineers to scientifically prove relations and yields of variables through manual calculations or simulation software. 

Reactors in chemical plants 

The reactors in chemical plants are usually the batch reactors, the Continuous Stirred Tank Reactors (CSTR), and the Plug Flow Tubular Reactor (PFTR). However, all the chemical plants use the Ideal reactor to simulate the reactor output and calculate the values and variables of different outputs. In the field of Chemical engineering, the reactions need to be exact, or else the chemicals may react differently and produce more undesired reactions than the desired reactions that may or may not be controlled by the use of the selectivity process. This is the primary reason behind the use of the ideal reactor simulation that is going to make the process accurate and the reaction output exact. 

Types of reactions

Series reactions: These are also called “consecutive reactions” and the reactants cause the manufacturing of the end product almost immediately. The formula for this is A – B – C. For example, the Ethylene Oxide can be made to react with Ammonia to form mono-di and tri-ethanolamine. 

Parallel reactions: These are also called “competing reactions” In this type of reaction the reaction yields two different products. In Chemical Engineering these are used to manufacture an element that happens as a by-product of two reactions. This reaction happens faster than the series reaction. 

Complex reactions: The complex reactions are categorised with both Parallel reactions as well as Series reactions. Usually, when more than three reactants are put in the chemical reactors the reactants first go through a series reaction and then split into the Parallel Reaction. This makes for a more complex manufacturing process and hence the name. 

Independent reaction: In this type of reaction the molecules from different reactant chemicals do not mix, or get adopted into the other reaction thereby stopping it from becoming a complex reaction. The best example of this is the purification of crude oil into gasoline. This is also another example of multiple reactions.

Use of selectivity 

Simply put, selectivity is the process that is used to reduce the undesired reaction in the chemical reactors.  The reactions happening partially to yield the final product in its desired chemical form in the chemical reactors are regulated by the use of the selectivity method that includes the addition of anodes and cathodes as well as other elements that neutralize or reduce (mostly reduce, rarely completely neutralize) the reactants that cause the undesired reaction by absorbing and releasing molecules of a particular reactant chemical to the other. One such example of selectivity is the “figure of merit”, the formula for selectivity is”

Selectivity = Modes of desired reactions formed

                     Modes of undesired reactions formed

This is used in chemical engineering for all the types of reactions that are by nature multiple reactions.


In conclusion, it can be said that the study of chemical reactions is one of the major parts of the students learning Chemical engineering and is an important part of the syllabus and scope for the students appearing for the GATE Exams. The study of the reactor types such as the ideal reactor is also a major part of the syllabus of the GATE Exam.  India is a country that produces many chemical engineers every year and they all are well trained in the process of chemical reactors and related subjects such as the study of the single reactions and multiple natured reactions in different real and simulated calculation reactors specifically focusing on the use of the Ideal reactor and its processes. 

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Frequently asked questions

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What is a yield?

Ans.Yield is usually fractional and can be defined by the moles of reaction formed divided by the molds that ...Read full

Why are ideal reactors used?

Ans : The ideal reactors are used to make the process of para...Read full

Can the selectivity process replace the use of ideal reactor calculations?

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