Vertical Shallow Air Flotation for Gas-Bearing Produced Water
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional oilfield produced water treatment processes face issues such as resource waste in gas flotation, high energy consumption, large floor space requirements, and high operation and maintenance costs, particularly in gas-bearing oilfields, due to inefficient gas bubble generation and complex processes.
Innovation Solution
A treatment device comprising a pressure stabilizing buffer tank, primary and secondary tubular dissolved air releasers, and high-pressure and low-pressure vertical cyclone flotation devices, utilizing microbubble generation and cyclone separation technologies to enhance gas flotation efficiency, with a compact design and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas flotation treatment is applied to produced water after three-phase separation, then oil-gas-water separation can be achieved, but dissolved gas must be re-injected causing resource waste and high operation costs
Solution Approach 1:
The system uses the dissolved gas naturally present in the produced water itself as the flotation medium, eliminating the need for external gas injection. The produced water serves its own separation needs through pressure reduction that releases dissolved gas for bubble formation.
Solution Approach 2:
The system changes the pressure parameter of the produced water from high pressure (after three-phase separation) to low pressure, causing dissolved gas to be released and form bubbles naturally. This parameter change enables self-flotation without additional gas injection.
2Ease of operation
If booster pumps are used to pressurize produced water after three-phase separation, then water treatment can proceed, but energy consumption increases significantly
Solution Approach 1:
Instead of pressurizing the water to achieve flotation, the system inverts the approach by reducing pressure to enable dissolved gas to escape and form bubbles. This inverse pressure application eliminates the need for energy-intensive booster pumps.
Solution Approach 2:
The system replaces the mechanical booster pump system with a pressure reduction mechanism that uses the natural properties of dissolved gas in produced water. This substitution eliminates the need for high-energy mechanical pressurization.
3Reliability
If conventional air flotation equipment is used, then gas flotation separation can be performed, but hydraulic retention time is long and floor space is large
Solution Approach 1:
The system transitions from horizontal flotation tanks to vertical flotation configuration. By changing the spatial dimension from horizontal to vertical, the system achieves the same separation function in a compact footprint, dramatically reducing floor space requirements.
Solution Approach 2:
The flotation process is segmented into distinct vertical zones: an upper gas-liquid separation zone and a lower water treatment zone. This segmentation allows for efficient use of vertical space while maintaining effective separation functionality.
4Reliability
If conventional air flotation equipment is used, then separation can be achieved, but operation and maintenance costs are high
Solution Approach 1:
The system uses naturally dissolved gas in the produced water as the flotation medium, eliminating the need for external gas supply systems, gas storage tanks, and associated injection equipment. This self-service approach drastically reduces operation and maintenance requirements.
Solution Approach 2:
The system extracts and utilizes the dissolved gas already present in the produced water for flotation purposes, removing the need for separate gas generation and injection systems. This extraction of useful resource from the waste stream simplifies the overall system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves high separation efficiency with a simple process flow, minimizing floor space and operational costs while effectively removing oil, gas, and solids from produced water, utilizing natural gas resources efficiently.
Implementation Method 1
high-pressure vertical cyclone floating device
Implementation Method 2
primary tubular dissolved air releaser
Implementation Method 3
low-pressure vertical shallow air flotation device
Implementation Method 4
microbubble generation
Implementation Method 5
pressure stabilizing buffer tank
Implementation Method 6
tubular dissolved air releaser
Implementation Method 7
microbubble generation
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided by the present application are a device and method for treating gas-bearing oilfield produced water on the basis of vertical shallow air flotation. The treatment device provided by the present application comprises a pressure stabilizing buffer tank, a dosing system, a primary tubular dissolved air releaser, a high-pressure vertical cyclone floating device, a secondary tubular dissolved air releaser, a low-pressure vertical shallow air flotation device, a slop oil tank, and a sludge tank. In the present application, tubular dissolved microbubble generation technology, air flotation separation technology, cyclone separation technology, shallow sedimentation strengthening separation technology and the like are organically combined, a large amount of dissolved air resources contained in produced water is effectively utilized, high-quality microbubble sources are provided for the high-pressure vertical cyclone flotation device and the low-pressure vertical shallow air flotation device by means of a pressure step release mode, efficient treatment of gas-bearing oilfield produced water is implemented, the treatment process of the gas-bearing oilfield produced water is greatly simplified, and treatment costs are reduced.