Types of Reactors [Advantage and Disadvantages and Their Application]

Hi everyone, today's post will cover the definition of a reactor, as well as the many types and uses of reactors, using examples.

With the help of catalysts, which explain how the reaction is occurring, reactions are categorized in chemical kinetics based on their pace and processes.

Let's get started on the topic of What a Reactor is right now.

What is a Reactor?

Reactors are process containers used for conducting chemical processes and reacting with other substances. The reactor, where chemical reactions take place, is frequently referred to as the process's "heart" in the chemical industry.

Chemical reactors are a necessary component of a manufacturing process since they transform raw materials into products. Numerous industries, including the chemical, polymer, dyes and pigment, color, and pharmaceutical sectors, among others, depend on reactors.

The industry has selection criteria for various types of reactors since reactor types vary based on the type of reaction and the properties of the raw materials.

Through the use of several examples, this essay will educate us about the different kinds of reactors utilized in the chemical industry. Now let's get started.

Types of Reactors

1. Batch Reactor
2. Continuous Stirred Tank Reactor (C.S.T.R)
3. Plug Flow Reactor (P.F.R)
4. Semi-Batch Reactor
5. Nuclear Reactor
6. Catalytic Reactor

#1 Batch Reactor

A closed vessel used for chemical processes is called a batch reactor, which is a type of non-continuous reactor. All of the reactants are first fed into the reactor at once. An agitator within the vessel thoroughly mixes the reactants to ensure an effective reaction and the production of products.

                       Batch Reactor

To control exothermic reactions, cooling coils are frequently used in batch reactors. Reactors of this sort employ characteristics to heat the reaction mixture, enabling it to be utilized in endothermic operations.

Because it is a transient, non-steady reactor, the amount of conversion occurs gradually inside the reactor. Because of the batch reactor's great degree of uniformity, the placement within the reactor has no bearing on the degree of conversion. These are employed to create solutions, such as chemicals for dosing, etc., and are likewise utilized in the pharmaceutical industry.

Advantages

• The versatility of a batch reactor is its main advantage.
• A large variety of reactants can be chemically reacted within the same batch reactor.
• When a reaction produces a lot of products, batch reactors come in handy.
• In lab settings, these are frequently employed to study the kinetics of liquid-phase reaction systems.

Disadvantages

• The drawback of batch reactors is the high labor costs associated with continuously charging reactants, discharging products, and cleaning the reactor.

Application of a Batch Reactor

Compounds are prepared for use in the reaction in these kinds of reactors. A batch of sodium sulfite is produced in the caustic chlorine industry and dosed into the brine to remove free chlorine at the dichlorination output.

#2 Continuous Stirred Tank Reactor (C.S.T.R)

Another name for a continuous stirred tank reactor (C.S.T.R.) is a mixed flow reactor (M.F.R.).  The reaction takes place in a closed tank in this reactor as well. To ensure that the reactants are well mixed, the tank additionally incorporates an agitator. It differs from a batch reactor in that it is a continuous piece of equipment.

          Continuous Stirred Tank Reactor (C.S.T.R)

At a specific mass flow rate, the reactants enter the reactor, react inside the vessel for a predetermined amount of time determined by the reactor's space-time, and subsequently create products. At the same mass flow rate, the products exit the reactor. One reactor volume can be processed in one space period.

C.S.T.R. stands for stable state apparatus. It implies that the degree of conversion is independent of time. The reactor's concentration is kept constant throughout by the agitator. It implies that the degree of conversion is independent of place as well. The reactor's volume determines how much of the material is converted.

Advantages

• The capacity of a C.S.T.R. to produce a vast quantity of things is the primary advantage for enterprises implementing it.
• It can operate continuously for hours on end since it is a continuous steady-state reactor.

Disadvantages

• One disadvantage of a C.S.T.R. is that it requires a very large reactor, therefore processes with very slow kinetics cannot be used with it.
• The reactor could not be practicable due to its production and operational expenses. This scenario makes use of a batch reactor.

Application of C.S.T.R

In the chemical industry, CSTR reactors are frequently used, especially in continuous facilities.

 #3 Plug Flow Reactor (P.F.R)

Another name for a plug flow reactor (P.F.R.) is a continuous tubular reactor (C.T.R.). This is an alternative kind of reactor where a fluid is injected or pushed through a pipe or tube containing one or more chemicals.

                                          Plug Flow Reactor (P.F.R)

These reactors are sometimes called plug flow or tubular reactors because of their tube-like design and internal reaction. There is a chemical reaction that happens as the chemicals pass through the PFR. 

A gradient is formed when the reaction rate varies for the distance traveled; at the inlet, the rate is extremely high to the PFR, but it drops as the concentrations of reagents and product(s) climb and decrease, respectively.

Advantages

• When it comes to space-time and conversion level, P.F.R. outperforms C.S.T.R.
• The P.F.R. has a somewhat smaller volume than a C.S.T.R.
• It shows that the reactor needs less room and that PFR has a higher conversion rate than CST.R. for a given reactor capacity.
• When examining the kinetics of gas phase catalytic reactions, the P.F.R. is commonly employed.

Disadvantages

• When it comes to space-time and conversion level, P.F.R. outperforms C.S.T.R.
• The P.F.R. has a somewhat smaller volume than a C.S.T.R.
• It shows that the reactor needs less room and that PFR has a higher conversion rate than CST.R. for a given reactor capacity.
• When examining the kinetics of gas phase catalytic reactions, the P.F.R. is commonly employed.

Application of P.F.R

PFRs are extensively utilized in industrial processes, including those that produce chemicals, pharmaceuticals, fertilizers, and petrochemicals. They also have a significant impact on polymerization processes, such as those that yield polyethylene and polypropylene.

#4 Semi-Batch Reactor

It is possible to process both batch and continuous inputs and outputs in a semi-batch reactor. These reactors mix batch and continuous operations. Semi-batch reactors are charged with reactants and raw materials. As the procedure goes on, chemicals are also introduced progressively over time.

                   Semi- Batch Reactor

An agitator will be used to maintain a constant temperature and composition throughout the reactor by stirring the reaction mass. Semi-batch reactions enable the addition of chemicals to a continuous process reaction.

Additionally, jackets with features that could be utilized to heat or cool the reaction mass under the demands of the chemical process were a feature of semi-batch reactors.

Advantages

• Many reactions may be conducted with greater control over yield or selectivity when using a semi-batch reactor.
• Since it makes it possible to alter the other reactant's flow rate, it is very helpful for performing exothermic reactions.

Disadvantages

• The disadvantage of the semi-batch process compared to the continuous process reactors (C.S.T.R. and P.F.R.) is that should we decide to scale it up, the capital costs per unit increase very dramatically
• Cleaning the reactors and blades, charging and discharging the reactor's contents, and other tasks need more effort.

#5 Catalytic Reactors

The primary sources of energy in these reactors are mass and heat transfer in addition to catalysts. Applications include the following: hydrogen cracking, polymerization, and chemical synthesis.

The catalyst movement pattern, as described below, determines the common categorization of these reactors:

1. Fixed Bed
2. Trickle Bed
3. Fluidized Bed

1. Fixed Bed Reactors

                Fixed Bed Reactors

Gas-phase heterogeneous catalyzed reactions are conducted using a fixed bed of catalysts. Depending on the needs, they can be constructed on one or many tubes.

Reactors classified as Fixed Beds typically come in two varieties: packed beds and multi-tube reactors.

2. Trickle Bed Reactors

            Trickle Bed Reactors

Trickle bed reactors, which are most frequently used for hydrogenation processes, use a solid phase as a catalyst to carry out gas-liquid reactions.

To improve contact surface area, gas reactants are introduced from the cross-current direction, while liquid reactants are introduced from the top and flow downhill to come into touch with the solid catalyst bed.

3. Fluidized Bed Reactors

                                Fluidized Bed Reactors

A pull of gas or liquid that is moving upward at a speed that causes the solid bed to act like a fluid supports a bed of solid particles. The reactor used to study this phenomenon is referred to as a Fluidized Bed Reactor.

#6 Nuclear Reactor

Atoms can split apart to release energy through nuclear fission processes, which are carried out in nuclear reactors. This involves the use of uranium-based nuclear fuel, such as uranium-235 and plutonium-239.

Nuclear Reactor

The goal of these is to keep the nuclear chain reactions in check. These reactors are used in nuclear power plants to generate energy. Uranium dioxide powder, which is crushed and processed into hard ceramic pellets, is produced by nuclear reactors by the reaction of fuel.

After that, the pellets are placed within fuel rods or tubes. The quantity of fuel rods depends on the reactor's capacity. Reactant temperature is controlled using reactor vessel control rods made of different materials having anti-reaction characteristics. To speed up the reaction, they are either removed from the reactor core or put into it.

Nuclear Reaction Applications

• Neutron scattering, radiography, radioisotope production, basic research, material testing, and characterization are among the applications for nuclear reactors.
• Advanced training and education in nuclear technology for energy and other applications, they are also essential resources.

These reactors consist of a bed of solid particles supported by a liquid or gas moving at a speed that causes it to behave like a fluid and flow upward. A fluidized bed reactor is the name of the reactor that was used to investigate these phenomena.

Conclusion

That is all. I appreciate your reading. I hope I covered all of the "Types of Reactors" in this post. If you could let me know anything I missed or if you have any questions regarding anything I wrote, that would be really helpful.

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Read More: 

1. Types of Valves
2. Types of Sensors
3. Types of Cycles
   

External Links:

1. https://chemicalengineeringworld.com/types-of-reactors/
2. https://en.wikipedia.org/wiki/Chemical_reactor