Classification, Selection and Characteristics of Reaction Kettle Agitators

作者:Shanghai Rumi Mechanical &Electrical Technology Co 浏览: 发表时间:2020-03-09 12:45:10

Reaction kettle is widely used in petroleum, chemical industry, rubber, pesticide, dye, medicine, food, used to complete the vulcanization, nitration, hydrogenation, alkylation, polymerization, condensation and other technological processes of pressure vessels

parts of reaction kettle

parts notes (translation): 1. agitator, 2.tank body, 3. Jacket, 4.mixing shaft, 5.pipe, 6.seat, 7. manhole, 8.shaft seal, 9. transmission device

Reaction kettle is composed of kettle body, kettle cover, jacket, agitator, driving device, shaft seal device, support and so on.


1. Shell of reaction kettle

The shell is composed of a round cylinder body, upper cover and lower head. There are two ways to connect the top cover with the cylinder body. One is welding the cover to the cylinder body as an integrate. Another option is to allow for easy disassembly and flange connection. The top cover has manhole, hand hole and process pipe, etc.


2. Stirring device of reaction kettle

In the reaction kettle, the reaction kettle is usually equipped with stirring device in order to speed up the reaction, strengthen the mixing and enhance the effect of mass transfer or heat transfer. It is composed of agitator and agitator shaft, which is connected with the transmission device by coupling.


3. Sealing of reaction kettle

The sealing used in the reaction kettle is a dynamic sealing structure, mainly including packing seal and mechanical seal.


Classification and selection of reaction kettle agitator

Classification and selection of reaction kettle agitator

                                                                                                                                                          Reaction kettle agitator function

Uniform mixing of materials to enhance heat and mass transfer, including homogeneous liquid mixing; Liquid-liquid dispersion; Gas-liquid dispersion; Solid-liquid dispersion; Crystallization; Solid solution; Enhance heat transfer, etc.


                                                                                                                                                        Working principle of reaction kettle

Agitator is the main part of agitator operation, its main component is the impeller, which along with the rotation axis motion will be mechanical energy to the liquid, and promote the liquid movement.


When the agitator rotates, the mechanical energy is transferred to the fluid, and a full mixing zone of high turbulence is formed near the agitator, and a high-speed jet is generated to push the liquid to circulate in the agitator.


Influencing factors of stirring in reaction kettle (see the previous article and instructions on stirring model selection for details)

The way in which a liquid circulates through the equipment is called a "flow model" or "flow pattern" for short.

Classification and application of reaction kettle agitator

Paddle agitators, propulsion agitators, turbine agitators and anchor agitators are widely used in stirring reaction equipment, accounting for about 75 ~ 80% of the total number of agitators.

1.  Paddle agitator

It consists of blades, keys, shaft rings and vertical shafts. Blades are usually made of flat steel or stainless steel or nonferrous metals. The rotating speed of paddle agitator is low, usually 20 ~ 80r/min. The inner diameter Di/3 ~ 2/3 of the reaction kettle is taken for the diameter of the paddle agitator. The blades should not be too long. When the diameter of the reaction kettle is large, two or more blades should be adopted.


Main application: paddle agitator is suitable for liquid materials with large fluidity and small viscosity, and also for dissolved solution in the shape of fiber and crystal. When the material layer is deep, several rows of blades can be installed on the shaft. The fold-blade type has less power consumption and lower operation cost than the flat-blade type, so the fold-blade type is more used.


Paddle agitators shall not be used in gas-liquid dispersion operations for gas retention and refinement purposes. The rotating speed of paddle agitator is generally 20 ~ 100r/min.

 2.Puopulsion agitator 

Puopulsion agitator can make the material circulate in the reaction kettle during stirring. The main function is volume circulation, with small shear effect and good up-and-down billowing effect. When a larger flow rate is required, the reaction kettle is provided with a diversion tube.


The standard propulsion agitator has three blades with pitch equal to the diameter d of the propeller. The diameter of the propulsion agitator is about 1/4 ~ 1/3, 300 ~ 600r/min of the inner diameter of the reactor. The agitator is usually made of cast iron and cast steel.


Characteristics of the propulsion agitator:


Axial flow agitator;


Large circulation volume, small stirring power;


Simple structure and convenient manufacturing;


Often used in low viscous fluids.

3.turbine agitator

The turbine agitator has a high speed of 300 ~ 600r/min. Straight and curved blade turbine agitators mainly produce radial flow, while fold-blade turbine agitators mainly produce axial flow.

The main advantage of turbine agitator is that when the energy consumption is low, the stirring efficiency is high and the stirring produces a strong radial flow. Therefore, it is suitable for emulsion, suspension, etc.

4. anchor agitator

Suitable for fluid stirring with viscosity below 100Pa·s. When the fluid viscosity is between 10 and 100Pa·s, a horizontal blade can be added to the middle of the anchor propeller, that is, the frame agitator, to increase the mixing in the middle of the container.


Features of anchor agitator:


Simple structure, easy to manufacture;


Suitable for materials with high viscosity and large handling capacity;


It is easy to obtain large surface heat transfer coefficient;


Can reduce "wall sticky".

Select the type according to the purpose of stirring (please communicate with Rumi technology engineer according to the specific process)


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