Selection of hydrocyclone structure diagram
Writer： admin Time：2020-08-03 11:13 Browse：℃
Hydrocyclone is a new type of equipment used for oil-water, mud-sand separation in oilfield sand washing operations. It uses centrifugal force instead of gravity to achieve liquid-solid separation. The basic structure of the hydrocyclone is composed of upper feed port II, cylindrical cavity V, conical cavity I, underflow port IV and overflow port III.
The basic principle of cyclone is that bai separates du liquid-liquid, liquid-solid, liquid-gas and other two-phase or multiphase mixtures with a certain density difference under the action of centrifugal force dao. The mixed liquid enters the cyclone tangentially at a certain pressure, and a high-speed rotating flow field is generated in the cylindrical cavity.
The dense components in the mixture simultaneously move downwards in the axial direction under the action of the swirling field, and move outwards in the radial direction. When they reach the cone section, they move downwards along the wall and are discharged from the underflow port, thus forming The outer vortex vortex flow field; the components with low density move to the direction of the central axis and form an upward moving inner vortex at the center of the axis, and then are discharged from the overflow port, thus achieving the purpose of two-phase separation.
Cyclone, as a typical device of the compound force field of centrifugal force and gravity, is widely used in many fields because of its simple structure, small footprint, convenient installation and operation, and low operating cost.
Small solids still account for about 5% of the total volume of solids, while solids with a particle size greater than 30 μm in the filtrate at the overflow still account for more than 65%. After measurement, the solid mass fraction of the underflow of the cyclone is obviously low, still less than 40%, and the operation is unstable. The mass fraction of solids in the underflow of the cyclone of unit A meets the requirements (the solids content is not less than 50%, but the water content of gypsum products is only qualified at the beginning of the operation in the dehydration process, and the water content of the water content gradually increases as the dehydration progresses.
How to select the type according to the structure drawing of the hydrocyclone?
The slurry is pressurized by the discharge pump and then sent to the cyclone for concentration and separation. Under the action of centrifugal force, the overflow of the cyclone forms filtrate water containing a small amount of solid particles, and most of the solid particles are discharged from the underflow port. The slurry discharged from the underflow port is further filtered and absorbed by a vacuum belt dehydrator to finally form gypsum with a water content of no more than 10%.
Small solids still account for about 5% of the total volume of solids, while solids with a particle size greater than 30 μm in the filtrate at the overflow still account for more than 65%. After measurement, the solid mass fraction of the underflow of the cyclone is obviously low, still less than 40%, and the operation is unstable. The mass fraction of solids in the underflow of the cyclone of unit A meets the requirements (the solids content is not less than 50%, but the water content of gypsum products is only qualified at the beginning of the operation in the dehydration process, and the water content of the water content gradually increases as the dehydration progresses.
Among them, the small particle area is mainly unreacted limestone particles, fine gypsum particles and impurities, and the large particle area is normal gypsum crystals. The 4-8 μm solid particles in the slurry at the inlet of the cyclone account for about 5% of the total solid volume, and the 30-70 μm solid particles account for about 70% of the total solid volume. However, when the underflow solid mass fraction of the cyclone meets the requirements, the water content of the gypsum product exceeds the standard, which is worthy of our in-depth analysis.
The basic working principle of the hydrocyclone is based on the different centrifugal force generated by the substances with different densities during the rotation process. The dense substances move in the outer circle, while the less dense substances move in the opposite direction to produce separation. The mixture of oil, cement, sand, etc. enters the cylindrical wall V of the cyclone tangentially from the upper feed port II under a certain pressure, and rotates at a high speed in the cone wall I of the cyclone. The light phase (oil and water) moves to the axis of the cyclone to form an upward internal swirling oil-water core; the heavy phase (mud sand) moves to the cyclone wall to form a downward external swirl.
Oil and water are separated and discharged from the overflow port III. Mud and sand and a small amount of water are discharged from the underflow port IV to achieve the purpose of separation.
There are many theories of hydrocyclone separation technology. These theories tell us that the factors affecting the separation efficiency and separation particle size of hydrocyclones can be summarized into three, namely:
1. The influence of structural parameters;
2, the influence of operating parameters;
3. The influence of material characteristics.
Research found that the hydrocyclone has reasonable design, simple structure, easy operation, safe and reliable work, high separation efficiency, and the minimum diameter of the separated sand particles is small (up to 8μm), which fully meets the requirements of phenomenon operation. The use of hydrocyclones reduces the cost of sand washing operations, saves water resources, shortens operations, reduces oilfield consumption and energy saving, and comprehensively improves economic benefits. It has good economic significance and broad promotion prospects.
