Plasma Discharge Stretching in Liquid via Gas Injection
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Solution Overview
Problem
High electric conductivity of produced water from hydraulic fracturing poses challenges for generating plasma discharges, as it behaves as a short circuit, preventing effective treatment methods for removing dispersed oil/grease, soluble hydrocarbons, and disinfection, and existing methods struggle to sustain plasma discharges in both high and low conductivity liquids.
Innovation Solution
A system and method involving a container with multiple electrodes and a gas injection conduit to introduce gas between electrodes, allowing for the generation and stretching of plasma discharges by controlling electrode connections and gas flow rates, enabling larger plasma discharges in high and low conductivity liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is injected to assist plasma discharge generation in high conductivity liquid, then plasma discharge can be generated, but the plasma discharge size is limited to small scale within electrode gap
Solution Approach 1:
The invention divides the plasma generation process into two distinct phases: first generating a small plasma discharge between closely spaced electrodes (2-5mm gap) to overcome the high conductivity barrier, then using that initial plasma as a seed to ignite a much larger plasma discharge between electrodes spaced farther apart (5-20cm gap). This segmentation allows the system to bypass the limitation of small plasma size by using a two-step ignition approach.
Solution Approach 2:
The invention performs a preliminary plasma discharge between closely spaced electrodes before attempting to generate the main large-scale plasma discharge. This preliminary action creates ionized pathways and reduces the breakdown voltage requirement, enabling the subsequent large plasma discharge to occur between electrodes that would otherwise be too far apart for direct ignition. The gas injection is timed to coincide with this preliminary phase to assist breakdown.
2Productivity
If electrode spacing is increased to achieve larger plasma discharge, then treatment efficiency improves, but plasma breakdown becomes difficult due to higher voltage requirements
Solution Approach 1:
The system performs a preliminary breakdown between closely spaced electrodes (2-5mm gap) that requires lower voltage, creating an ionized plasma channel. This preliminary action prepares the pathway for subsequent plasma propagation to distant electrodes (5-20cm away), eliminating the need to directly overcome the high voltage barrier of the full electrode spacing. The gas injection assists this preliminary breakdown phase.
Solution Approach 2:
The initial plasma discharge between closely spaced electrodes acts as an intermediary that mediates the energy transfer from the power supply to the larger plasma volume. Instead of directly applying high voltage across the full electrode gap, the system uses the initial plasma as an intermediate conductive pathway that enables subsequent plasma formation at lower voltage requirements over longer distances.
3Reliability
If high voltage is applied to generate plasma in high conductivity liquid, then plasma discharge occurs, but electrons flow directly through liquid creating short circuit
Solution Approach 1:
Gas bubbles introduced between the electrodes serve as an intermediary medium that blocks direct electron flow through the conductive liquid. The gas phase creates a resistive barrier that prevents electron leakage and short-circuiting, while still allowing plasma discharge to occur through the gas-filled pathway. This intermediary gas layer enables plasma generation without the energy loss associated with direct electronic conduction through the liquid.
Solution Approach 2:
The invention creates a localized gas-filled region between the electrodes where plasma discharge is desired, while the surrounding liquid maintains its natural properties. The gas injection is targeted specifically at the electrode interface region, creating a local modification of the medium's electrical properties (from conductive liquid to resistive gas) precisely where plasma generation is needed, without altering the bulk liquid properties.
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 method achieves significantly larger plasma discharges, increasing treatment efficiency and power delivery, effectively addressing the challenges of high conductivity liquids like produced water and low conductivity liquids such as hydrocarbon fuels, while enhancing the removal of contaminants like bicarbonate ions.
Implementation Method 1
introducing a gas between the first and second electrode to generate a group of bubbles
Implementation Method 2
generating a first plasma discharge between the first and second electrodes
Implementation Method 3
breakdown of air between the two electrodes takes place, generating a discharge of plasma
Implementation Method 4
a large number of gas bubbles are generated from both electrodes, due to electrolysis
Data Source
AI summary
A system and method for stretching the discharge of plasma in a liquid utilizes in certain embodiments a first, second and third electrode within a liquid holding container, a gas injection conduit for introducing a gas such as air or oxygen into the container, and a power supply electrically coupled to at least the second and third electrodes. In certain embodiments, a seed plasma generated by a first and second electrode is stretched, and a larger plasma is generated by a first and third electrode. In certain embodiments, a fourth electrode can be used to further stretch the plasma. An increase in gas introduction flow rate can also be utilized to facilitate the stretching of plasma.