For oil and water separation treatment, commonly used to have oil and water separator. Oil and water separator is also called oil and water separator, its main principle is to use the different proportion of oil and water, the use of filtration, precipitation, buoyancy and other methods to bring together the separation of oil and water.
1. Air flotation separation
Air float method is a method of purifying water by forming tiny bubbles in water and carrying floc particles up to the liquid surface. The condition is that the bubbles attached to the oil droplets can form oil-gas particles. Due to the appearance of bubbles, the density difference between water and particles increases, and the diameter of particles is larger than that of oil droplets, so the rising speed can be significantly increased by substituting the density between particles for the density of oil droplets. That is, when one bubble (or more bubbles) attached to one oil drop can increase the vertical rise speed, so that the diameter of much smaller than 50μm oil drop can be removed.
Gravity separation
Because the relative density of oil, gas and water is different, the composition must be oil and water mixture under a certain pressure and temperature, when the system is in equilibrium will form a certain proportion of oil, gas and water phase. When the lighter component is in laminar flow state, the larger component drops settle according to stokes formula, and the gravity settling separation equipment is designed according to this basic principle. Stokes formula shows that the sedimentation velocity is directly proportional to the square of the radius of water in the oil, directly proportional to the density difference between water and oil, and inversely proportional to the viscosity of oil. By increasing water density, increasing oil-water density difference and decreasing oil viscosity, sedimentation separation speed can be improved and separation efficiency can be improved.
After further exploration, In 1904, Hazen proposed the "shallow pool theory" d on practical experience, that is, in the process of gravity settlement, the settling effect of dispersed particles rather than fluted particles is measured by the settling velocity of particles and the pool area as a function, and has nothing to do with the pool depth and settling time. In other words, there are two ways to improve the processing capacity of the settling pool: One is to expand the settlement area, the other is to improve the speed of water settlement. Stokes formula can be used to improve the rate of water settlement, and the measure to expand the settlement area is to install multi- horizontal separators in the container. d on this theory, the first parallel plate trap was developed by American Shell in 1950, which could remove oil droplets as small as 60μm from water. In the 1970s, Fram developed the V-shaped plate separator, and in the 1980s ce-Natco developed the plate coalescer, a type of split-flow combined corrugated plate. After continuous improvement, this equipment has been used in oil and gas separation, oil and water separation and oily sewage purification.
On the basis of in-depth study of oil-water separation mechanism, an efficient evaporation equipment is developed according to the corresponding theory, which can be roughly divided into three parts according to the separation process: pre-separation chamber, sedimentation separation chamber, oil chamber and water chamber. The pre-separation chamber is generally equipped with disc steering device and homogeneous liquid distribution plate. Its principle is to strengthen mechanical demulsification by changing the running direction and flow rate of oil-water emulsion for many times, so as to further speed up oil-water separation. The interface film strength of emulsion can be greatly reduced by active water washing. Due to the shear and friction between emulsion and other s, the interface film is broken, and the droplet coalescence is promoted, the particle size becomes larger, and the oil-water separation is accelerated. The settlement separation chamber mainly plays the role of further separation and purification, and the oil-water separator is the key of the design.
Coarse-grained evaporation of emulsified water
The use of oil and water on the solid substance affinity state of the different, commonly used hydrophilic hydrophobic solid substances made of various evaporation devices. Solid materials used for oil-water separation should have good wettability. Materials suitable for this requirement are: ceramics, wood chips, fiber materials, walnut shell and so on. For example, the ceramsite evaporator in Dagang oilfield uses ceramsite as filler. When the mixture of oil and water flows through the ceramsite , it is forced to constantly change the flow rate and direction, which increases the probability of collision and coalescence of water droplets and makes small droplets quickly coalesce and settle.
