Device and method for bleed air backflow recycling multi-stage baffling microbubble flotation oil removal

Abstract

The invention provides a device and a method for deoiling by entraining, refluxing and reusing multistage baffling microbubble flotation, and relates to the technical field of deoiling of oilfield produced water. The multistage baffling microbubble flotation oil removal device for entrained air backflow recycling comprises an air flotation tank, a dissolved air pump and an electric control system, and a vortex reactor, a T-shaped water passing opening and an adjustable oil collecting groove are arranged in the air flotation tank; a nitrogen pressure automatic balancing pipeline system, a nitrogen entraining return pipeline, a dissolved air water replenishing pipeline, a dissolved air water return pipeline and an oil-containing raw water extraction pipeline are arranged outside the air floatation tank; the air dissolving efficiency is improved and the particle size of microbubbles is reduced by controlling the inlet and outlet pressure of an air dissolving pump; the vortex reactor slows down the bubble gathering and floating speed and prevents short flow; according to the nitrogen pressure automatic balancing pipeline system, a stable gas phase space can be formed at the inner top of the air floatation tank, the liquid level is kept stable, separated nitrogen serves as a gas source of the gas dissolving pump to be recycled, and the consumption of the nitrogen is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of deoiling oilfield produced water, in particular to a device and method for deoiling oil by multi-stage baffled microbubble flotation for bleed air backflow. Background technique [0002] Micro-bubble flotation oil removal in the oil-bearing produced water technology in oilfields, that is, air flotation oil removal, is to generate a large number of fine air bubbles in the water through the dissolved air system, so that the air is attached to the suspended particles in the form of highly dispersed fine air bubbles, resulting in The density is less than that of water, and the principle of buoyancy is used to make it float on the water surface, so as to realize the water treatment process of solid-liquid separation or liquid-liquid separation. At present, the air flotation methods are mainly divided into dissolved air flotation, multiphase flow dissolved air pump air flotation, jet air flotation, electroflocc...

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Problems solved by technology

[0003] The traditional multiphase flow dissolved air pump air flotation device is used for oil removal, and the main problems are as follows: (1) The nitrogen consumption is large during the gas dissolution process; (2) The gas dissolution efficiency is low, and most of the gas-liquid ratios are <5%. Some dissolved air pumps also need to install a gas-liquid separation tank at the pump outlet to discharge the gas that cannot be dissolved in water; (3) The dissolved air water pipeline is vertically inserted into the raw water pipeline, and the loss of dissolved air water and raw water is large after mixing, and the dissolution effect is poor. Short flow is easy to occur during the backward push flow operation, and the flotation degreasing effect is poor

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