Stirrer is one of the key components of the reactor device, according to the physical properties of different media in the kettle, capacity, stirring purpose of the selection of the appropriate stirrer, to promote the speed of chemical reaction, improve production efficiency can play a great role. Mastering the classification of stirrer and applicable occasions will help to choose the right stirrer and achieve better reaction effect.
Application of reaction kettle device:
Reaction kettle is widely used in petroleum, chemical, rubber, pesticides, dyes, medicine, food, used to complete the process of vulcanisation, nitration, hydrogenation, hydrocarbonation, polymerisation, condensation and other processes of pressure vessels.
Composition of reaction kettle device:
The reaction kettle is composed of kettle body, kettle cover, jacket, stirrer, transmission device, shaft sealing device, support and so on.
1、Shell of reaction kettle
The shell consists of round cylinder, upper cover and lower head. There are two ways to connect the cover with the cylinder, one is the cover and the cylinder directly welded to form a whole; another form is to consider the ease of disassembly, available flange connection. The upper cover is opened with manholes, hand holes and process receivers.
2、Stirring device of reaction kettle
In the reaction kettle, in order to speed up the reaction speed, strengthen the mixing and strengthen the mass or heat transfer effect, the reaction kettle is generally equipped with stirring device. It consists of stirrer and stirring shaft, with coupling and transmission device into one.
3、Reaction kettle sealing device
The sealing device used in the reaction kettle is a dynamic sealing structure, mainly two kinds of packing seal and mechanical seal.
Classification and selection of reaction kettle device agitator:
The role of the reaction kettle stirrer:
Make the material mixing uniform, strengthen heat and mass transfer, including homogeneous liquid mixing; liquid-liquid dispersion; gas-liquid dispersion; solid-liquid dispersion; crystallisation; solids dissolution; strengthen heat transfer and so on.
Reactor stirring principle:
Stirrer is the main component to achieve the stirring operation, and its main component is the impeller, which moves with the rotating shaft to apply the mechanical energy to the liquid and prompt the liquid to move.
When the stirrer rotates, the mechanical energy is transferred to the fluid, forming a highly turbulent full mixing zone near the stirrer, and generating a high-speed jet to push the liquid to circulate in the stirring vessel.
Reactor stirring influences:
Liquid within the scope of the equipment for the circular flow of the pathway called the liquid ‘flow model’, referred to as ‘flow pattern’.
Flow pattern and stirring effect, stirring power is very close. Flow pattern depends on the form of stirrer, stirring vessel and the geometric characteristics of the internal components, as well as the nature of the fluid, stirrer speed and other factors.
Axial flow:
The direction of fluid flow is parallel to the mixing axis, and the fluid is pushed by the paddle, so that the fluid flows downward and meets the bottom of the container and then turns upward, forming an up-and-down circulation flow.
Radial flow:
Fluid flow direction perpendicular to the mixing axis, along the radial flow, meet the container wall into two streams of fluid were upward, downward flow, and then back to the end of the blade, not through the blade, the formation of the upper and lower two cycle flow.
Tangential flow:
No baffle container, the fluid around the axis for rotary motion, high flow rate when the liquid surface will form a vortex, the fluid from the paddle around the circumferential coil suction to the paddle area of the flow is very small, the mixing effect is very poor.
The above three types of flow usually exists at the same time;
Axial flow and radial flow play a major role in mixing;
Tangential flow should be suppressed – the use of baffles can weaken the tangential flow, enhance the axial and radial flow.
Post time: Sep-13-2024