Chemical Reactor

A reactor is a device in which these chemical reactions take place. Chemical reactors can be built on a large scale for industrial use or on a small scale for laboratory and research applications.
In a chemical plant, the raw materials or the same components are passed through a series of primary physical processes such as separation and purification until they are ready to enter.

At this stage, using a suitable reactor or reactors, the chemical changes in question are performed and the product is produced. Due to some unwanted reactions or the existence of some of the input materials to the reactor that did not find the opportunity to perform the reaction, and along with the product of the reactor, the product is not marketable to the market and it is necessary for physical operations such as separation , Refinement is performed on it, then it is presented to the market as the final net product for sale.

In a chemical process, it is possible that not all of the raw materials are consumed in the reactor; There is; Therefore, the amount of raw materials that are not used in the reactor must be returned to the reactor, which is called the return current.

In the chemical industry, the reactor is considered as the heart of the chemical process and the most important and sensitive operations in the plant.

Discontinuous Reactors

Discontinuous reactors have been used since the beginning of the chemical industry and are still widely used in the production of high value-added chemicals.

In these reactors, raw materials or the same components enter the reactor at the very beginning of operation. The contents of the reactor are thoroughly and vigorously mixed for a specified period of time, and after a certain period of time the reaction proceeds, the contents of the reactor are discharged; Therefore, in this reactor, no mass enters and no mass exits during the reaction.

Components of Continuous Reactors

1. Body:
The body is the most important part of the reactor and is the place of reaction and storage of the product. Material related to materials, if corrosive, is usually 316L stainless steel and in other cases ordinary steel. And it is usually in the form of cylinders. Nozzles are installed on the body for material entry and exit. Product sampling.
 
2. Wall:
Because the chemical reactions are either hot or the heat sink is placed on the body of the wall. The function of the wall is to transfer or give heat to the product indirectly. The wall is installed either as a complete or in the form of thermal coils, which themselves are in the form of a semicircle or in the form of studs, which are placed in a spiral manner around the reactor. In the walls, a stream of water or oil with Higher or lower temperatures are used to transfer heat.

3. Butter and stirrer:
The process of mixing and mass transfer in reactors is of great importance, because if the contents inside the reactor are not well combined, it will be possible for some of the material not to react and the result will be reduced. Stirring operation in tank-shaped reactors is performed using rotary agitators connected to the impeller, which is connected to the shaft and the electric motor.

4. بفل:
Buffers are vertical blades that are mounted on the body and their job is to help mix the product by changing the flow of fluid from slow to turbulent flow. The material of the baffle is usually the same as the material of the body, and the way it is placed and installed is selected according to the design requirements.

Semi-Continuous Reactors

These types of reactors have various types. In the conventional type, one of the raw materials is first filled inside the reactor and then gradually other material or raw materials are added to it.

In the other type, the raw material enters the reactor simultaneously, but no material leaves the reactor until the end of the reaction.
Another type is that all the raw materials are loaded inside the reactor and during the reaction the materials inside the reactor are gaseous and are discharged from the reactor.

Semi-discontinuous reactors have the same limitations as discontinuous reactors. The advantages of semi-discontinuous reactors are good temperature control and control of adverse reactions and limiting the production of unwanted products. This is achieved by gradually introducing one of the low-concentration components. Semi-continuous reactors are often used for two-phase reaction in which one of the components is gas, and the gas component is fed in the form of a bubble into the liquid phase inside the reactor.

Continuous Reactors

In these types of reactors, the raw material enters the reactor continuously and after the reaction, the product is continuously discharged from the reactor. Such reactors are used in industry when the goal is to produce large quantities of products, while continuous reactors are more suitable for performing rapid reactions. These reactors are used in many chemical industries, especially in the oil, gas and petrochemical industries.

Continuous Stirring Tank Reactors

Continuous stirring tank reactors are common types of reactors in which one or more systems enter the system, bring the composite material into the reactor, and after evaporating, exit. Normally the input and output current of these reactors is constant, otherwise there is a possibility of rapid overflow or draining of the reactor tank, there is a need for extreme adjustment, it is used. Mixed reactors are made either alone or in the form of mixing and smoothing the material with shafts and impellers.

Compared to other reactors, the conversion rate of materials in them is lower per unit volume of product, and therefore, in order to achieve a higher conversion rate, the product is considered larger. Mixed reactors are used for most homogeneous reactions in the liquid phase.

In mixed reactors, due to the presence of homogeneity, the inlet feed is rapidly dispersed throughout the container and the concentration is approximately the same at each point inside the container; Therefore, the reaction speed is almost the same at all points within the system. In mixed reactors, there are no spatial changes in concentration (or physical properties) inside the reactor or at its output, and the properties within the system are uniform. These types of reactors are mainly used for the production of high volume products such as petrochemicals, detergents and hygiene products in large volumes.