Grinding and dispersing machine for coal water slurry preparation

Special 18000 RPM disperser for coal water slurry, nano disperser, high shear disperser, pipeline disperser, German high-speed disperser

Traditional coal water slurry mills can generally grind coal water slurry to 200-300 mesh, with a solid content of about 47-48%, which leads to a sharp increase in production costs. Currently, several large coal chemical enterprises' coal water slurry projects are in a loss making state. Only when the solid content of coal water slurry increases to 52% or more, can the production of coal water slurry be profitable. Recently, Taicang Xide Company and a large domestic coal chemical group conducted joint experiments to verify that the experimental high-speed shear disperser can increase the solid content of coal water slurry to between 60-65%, and the average particle size can be processed to 1500 mesh. Before the IKN high-speed shear disperser, a conveying pump (recommended to use a rotary pump or screw pump) needs to be equipped to ensure uniform feeding.

A high concentration coal water slurry high-speed shear disperser is an equipment that efficiently, quickly, and uniformly transfers one or more phases (liquid, solid) into another immiscible continuous phase (usually liquid). When the fineness of one or more materials reaches the micrometer or even nanometer level, the system can be considered homogeneous. When external energy is input, the two materials recombine into a homogeneous phase.

Due to the strong kinetic energy brought about by the high tangent speed and high-frequency mechanical effect generated by the high-speed rotation of the rotor, the materials in the high shear grinding disperser are subjected to intense mechanical and hydraulic shearing, centrifugal extrusion, liquid layer friction, impact tear and turbulence in the narrow gap between the stator and rotor, forming suspension (solid/liquid), lotion (liquid/liquid) and foam (gas/liquid). The high shear homogenizer instantly disperses and emulsifies immiscible solid, liquid, and gas phases uniformly and finely under the combined action of corresponding processes and appropriate additives. Through the cyclic operation of the high-frequency pipeline high shear dispersion homogenizer, stable high-quality products are finally obtained.

The preparation process and equipment of coal water slurry in China were introduced from the cement and mining industries during the period of "Sixth Five Year Plan" to "Ninth Five Year Plan" using rod mills or ball mills for slurry preparation technology. The technology and equipment have not been upgraded yet, and there are many problems such as high equipment power, high slurry energy consumption, low slurry concentration, and poor coal quality.

Taking the preparation of gasification coal water slurry by the current ****** rod mill with a diameter of 4.3 × 6m as an example, its rated dry coal feeding rate (coal used for Shenhua gasification) is 75t/h, the slurry concentration is only about 60%, equivalent to 125t/h of coal slurry, and the equipment motor power is 1600kW. Considering the raw coal, crushing, transportation and other links, the energy consumption per ton of slurry is ≥ 18kWh, which is relatively high; However, using Shenhua coal commonly used in coal water slurry gasification as raw material, the concentration of coal water slurry prepared by rod mill pulping technology is only about 60%. The lower coal slurry concentration leads to generally low gasification efficiency of coal water slurry, high specific coal consumption and oxygen consumption, and low effective gas content, resulting in waste of energy resources and energy, which is a major problem that urgently needs to be solved in the development of the coal chemical industry.

High concentration coal water slurry high-speed emulsion machine is mainly used for the production of micro lotion and ultra-fine suspension. Since three groups of dispersion heads (stator+rotor) in the working chamber work at the same time, after high shearing, the lotion drops are more delicate and the particle size distribution is narrower, so the stability of the generated mixed liquid is better. The three sets of dispersing heads are easy to replace and suitable for different process applications. The different models of machines in this series have the same line speed and shear rate, making it very easy to expand production. The appropriate temperature, pressure, and viscosity parameters are the same as DISPERSING. It also complies with CIP/SIP cleaning standards and is suitable for various types of production.

Introduction to dispersion effect：Dispersion is a thermodynamically unstable system composed of at least two incompatible liquids. One liquid is dispersed in spherical units in another liquid, so the more stable the dispersion, the better the dispersion effect.

From the perspective of equipment, there are several factors that affect the dispersion effect, including:

1. Form of dispersion head (batch and continuous) (continuous is better than batch)

2. The shear rate of the dispersing head, (the larger the effect, the better)

3. The tooth structure of the dispersing head (divided into initial teeth, middle teeth, fine teeth, ultra-fine teeth, and finer teeth for better effect)

4. The residence time and dispersion time of materials on dispersed walls (can be regarded as equivalent motors, the smaller the flow rate, the better the effect)

5. Number of cycles (the more cycles, the better the effect, and by the end of the device's lifespan, it cannot be any better.)

Working characteristics of high-speed disperser:

The strong centrifugal force throws the material radially into the narrow and precise gap between the stator and rotor, while being subjected to comprehensive forces such as centrifugal compression, liquid layer friction, and hydraulic impact, causing the material to be initially dispersed.

The high-speed rotating rotor of the disperser generates a linear velocity of at least 15m/s, and the material is fully dispersed and broken under strong hydraulic shear, liquid layer friction, tearing and collision, while being ejected at high speed through the stator slot.

The material of the disperser is continuously ejected from the radial direction at high speed, changing its flow direction under the resistance of the material itself and the container wall. At the same time, under the action of the upper and lower axial suction forces generated in the rotor area, two strong turbulent flows are formed, one above and one below. The material undergoes several cycles and finally completes the dispersion process.

Grinding and dispersing machine is a high-tech product composed of colloid grinding and dispersing machines.

The first level consists of three-level sawtooth protrusions and grooves with increasing precision. The stator can be infinitely adjusted to the desired distance between the rotors. Under enhanced fluid turbulence. The groove can change direction at each level.
The second stage is composed of a stator. The design of the dispersing head also effectively meets the needs of substances with different viscosities and particle sizes. The difference in the design of the stator and rotor (emulsifying head) between online and batch machines is mainly due to the requirements for conveying performance. It is particularly important to note that the difference between coarse precision, medium precision, fine precision, and other types of working heads is not only the arrangement of specified rotor teeth, but also an important difference in the geometric characteristics of different working heads. The width of the slot and other geometric features can alter the different functions of the stator and rotor working heads.

The following is a model table for reference:

Grinding and dispersing machine for coal water slurry preparation