Selection and installation of the hottest mixing e

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Selection and installation of mixing equipment

Introduction to mixing equipment

mixing equipment is generally composed of container part, transmission device, heat exchange equipment, mixing device and shaft seal device. It has a wide range of applications in industrial production, especially in the chemical industry, many chemical production are more or less used in mixing operation. Stirring equipment is used as a reactor in many occasions. For example, in the production of the three major synthetic materials, stirring equipment as the reactor accounts for about 90% of the total number of reactors

the functions of mixing equipment include the following points:

■ make the materials mix evenly

■ make the gas disperse well in the liquid phase

■ make solid particles (such as catalyst) uniformly suspended in the liquid phase

■ evenly suspend or fully emulsify another incompatible liquid phase

■ strengthen interphase mass transfer (such as absorption)

■ enhanced heat transfer

stirring equipment is mostly used in petrochemical production for material mixing, dissolution, heat transfer, suspension preparation, polymerization reaction, catalyst preparation, etc

selection of mixing equipment

the selection of mixing equipment includes several factors: Volume circulation rate, turbulence intensity and shear effect. Here we choose according to the viscosity of materials, which can be basically divided into two categories: low viscosity mixed system and high viscosity (non-Newtonian) mixed system. The low viscosity system is usually relatively simple, and the propulsion type, paddle type, turbine type, brumakin type, etc. can be well applied; Because the high viscosity system is mostly in laminar flow state, the shear stress near the impeller and above the container is the universal material testing machine, which industries are suitable for use? It is very important to choose what to pay attention to. Whether the internal liquid flow circulation is good and the size of the dead corner are very important to the mixing effect. Generally, frame type, spiral belt type, double spiral belt type and other mixing forms are used. For heat sensitive materials, wall scraping plates can be added

installation form of mixing equipment

vertical container central mixing

the mixing device is installed on the center line of the vertical equipment barrel. The driving mode is generally belt drive and gear drive, which are directly connected with ordinary motors or reducers

eccentric mixing

the mixing device is installed eccentrically on the vertical container, which can prevent the "cylindrical rotating area" of the liquid controlled by 4 measuring tools near the mixer, and can produce a mixing effect similar to that when adding baffles. Eccentric mixing will make the mixing center deviate from the center of the container, which will make the pressure of the liquid flow at each point different, so as to strengthen the relative movement between the liquid layers, increase the turbulence between the liquid layers, and significantly improve the mixing effect. However, eccentric mixing is easy to cause vibration, which is generally used in small equipment

inclined mixing

in order to prevent the generation of eddy current, for simple cylindrical or square open vertical equipment, the mixer can be directly installed on the upper edge of the mixer of the equipment cylinder with a splint or chuck, and the mixing shaft is obliquely inserted into the cylinder. The agitator of this kind of mixing equipment is small, light, simple in structure, easy to operate and widely used

bottom mixing

the mixing device is at the bottom of the equipment. Advantages of bottom mixing: the mixing shaft is short, thin, without intermediate bearings, and can be sealed mechanically, which is easy to maintain and repair, and has a long service life. Disadvantages: there are often solid substances on the shaft from the lower part of the impeller to the shaft seal, which are easy to become small lumps of materials. There is no more advanced problem of the two when mixed, and the product will affect the quality. In addition, when repairing the agitator and shaft seal, it is generally necessary to drain the materials in the kettle

horizontal vessel stirring

the agitator is installed on the horizontal vessel, which can reduce the installation height of the equipment, improve the seismic resistance of the equipment, improve the state of the suspension, etc. It can be used to stir materials of vapor-liquid heterogeneous system

side entry mixing

the mixing device is installed on the side wall of the cylinder, so the function of the shaft seal structure, namely u and O, is the key. It is generally used to prevent the accumulation of crude oil storage tanks and mud, for the uniform mixing of heavy oil, gasoline and other petroleum products, and for the mixing and sedimentation of various liquids. Specifically, it can be divided into side entry mixing with fixed angle and variable angle. (end)

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