Flotation technology in oily wastewater treatment have?

In sewage purification, according to the formation of air bubbles in water and air bubble senior colonel flotation process can be divided into four types, namely gas dissolved air flotation, Japanese float induced air flotation, electricity and chemical air flotation. One of the commonly used method has the following several kinds: gas pressurized dissolved air flotation, the impeller type air flotation and jet air flotation.
1
, dissolved air flotation method dissolved air flotation process can be divided into full flow pressure type, return flow, part of raw water and compressed air, four kinds of full flow pressure dissolved air flotation method of dissolved gas is large, the flotation cell volume small, widely used in oilfield sewage treatment; Return flow dissolved air flotation method is a part of the purification of water back into the dissolving tank pressurization dissolved air, then with to liquid into the flotation cell, therefore, can be in raw water need to advance the coagulation and raw water oil content is higher under the condition of use; Part of raw water dissolved air floatation method and the whole flow pressurized dissolved air flotation method of similar type, is suitable for oilfield sewage processing oil content is low; Pneumatic dissolved air flotation method is through the porous plate, perforated plate, or a special kind of nozzle, the gas pressure in the liquid, than other kinds of dissolved air flotation technology of short residence time.
2, jet flotation method
jet flotation method is to use the principle of jet pump, use water or purified water for injection fluid, when the water through high-speed nozzle, the nozzle form negative pressure suction chamber, gas is sucked suction chamber, the high speed water by mixing section, carrying gas is cut into tiny air bubbles; In flotation cell, the bubble buoyancy and adhesion on the oil and solid particles, it brought to the surface. Liquid-gas jet pump instead of rotating impeller, it can be used to power a water pump, greatly save the energy consumption, only about half of the impeller flotation bubble diameter is small, and manufacturing installation, convenient maintenance, safe in operation and has a great deal of research and application prospect. But so far, domestic also in jet flotation device have no systematic study.
3, impeller flotation process
air flotation depend on high-speed rotating impeller impeller to produce tiny bubbles. Bubble formed by mechanical mixing in the oily sewage, residence time is short, high oil removal rate, low cost, to adapt to the changes in water oil content. WEMCO company produces the impeller flotation machine is widely used, running effect is good. Some of the big domestic oilfield, liaohe oilfield, shengli oilfield and xinjiang oilfield successively introduced the flotation machine [ 2] 。 Impeller flotation machine, however, there is the manufacture, maintenance trouble, high energy consumption. In order to overcome the shortcoming of the flotation machine, a jet flotation device.