Microbubble Generator for Plasma Liquid Treatment
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Solution Overview
Problem
Existing plasma reactors for liquid treatment have limitations in generating and retaining plasma-treated gas within a closed system, leading to material loss and inefficient treatment due to gas escaping to the atmosphere and pressure drops, especially when dealing with high electrolytic conductivity liquids.
Innovation Solution
A system incorporating a sparger for generating large gas bubbles and a microbubble generator to produce submicron-sized bubbles, allowing the re-injection of plasma-treated gas into the liquid, maintaining pressure and enhancing treatment efficiency by ensuring active chemical species remain within the liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is injected into liquid to assist plasma discharge generation, then plasma discharge can be effectively generated in high electrolytic conductivity liquid, but the plasma-treated gas escapes to the atmosphere causing material loss and pressure drop
Solution Approach 1:
The system recovers plasma-treated gas by capturing it in a headspace above the liquid and then re-injecting it back into the liquid through a microbubble generator, preventing gas loss to the atmosphere while maintaining plasma treatment effectiveness
Solution Approach 2:
A microbubble generator acts as an intermediary device that converts the plasma-treated gas into submicron-sized bubbles, enabling the gas to remain suspended in the liquid and facilitating continuous plasma treatment without escaping to the atmosphere
2Reliability
If large gas bubbles are generated to fill the space between electrodes, then plasma ignition occurs effectively, but the gas bubbles rise and escape to the atmosphere
Solution Approach 1:
The system segments gas bubbles into two size categories: large bubbles (1-3 mm) for plasma ignition between electrodes and submicron-sized bubbles for suspension in the liquid. This segmentation allows each bubble type to fulfill its specific function without escaping
Solution Approach 2:
The microbubble generator changes the size parameter of gas bubbles from millimeter scale to submicron scale, fundamentally altering their behavior in the liquid. Submicron bubbles remain suspended due to balanced buoyancy and drag forces, preventing escape while maintaining plasma treatment capability
3Ease of operation
If open-ended plasma reactor is used, then gas can escape freely, but pressure drops to zero gage pressure requiring pump and active species are lost
Solution Approach 1:
The system creates a closed inert environment (headspace) above the liquid that captures plasma-treated gas. This closed atmosphere prevents gas and active species from escaping to the external environment, maintaining pressure and enabling continuous treatment without pumps
4Productivity
If submicron-size gas bubbles are generated, then plasma-treated gas mixes effectively with liquid, but such small bubbles cannot fill the space between electrodes for plasma discharge
Solution Approach 1:
The system segments gas bubble generation into two distinct functions: a sparger produces large bubbles (1-3 mm) for filling electrode space and enabling plasma discharge, while a microbubble generator produces submicron bubbles for effective mixing and suspension in the liquid. Both functions are achieved simultaneously through separate devices
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 system effectively disperses plasma-treated gas back into the liquid, maintaining pressure and enhancing treatment efficacy by prolonging the presence of active species, such as H2O2 and radicals, for effective disinfection and oxidation processes.
Implementation Method 1
the sparger includes pores of at least 1 mm in size for the gas from the gas source to flow through
Implementation Method 2
the microbubble generator includes pores in the range of 0.1 to 5 micron in size for the gas from the head-space to flow through
Implementation Method 3
these microbubbles stay in liquid for long durations in time because the force of buoyancy is at an order of magnitude comparable with drag
Implementation Method 4
breakdown of air between the two electrodes takes place, generating plasma discharges
Implementation Method 5
When the voltage between the two electrodes increases to a certain value such as 2 kV, breakdown of air between the two electrodes takes place, generating plasma discharges
Implementation Method 6
the conduit between the head-space and the microbubble generator includes a compressor pump
Data Source
AI summary
A system for the plasma treatment of a liquid is described. The system includes a storage chamber containing a liquid and a head-space, a gas source connected to a sparger positioned within the liquid, a pair of electrodes positioned within the liquid and substantially above the sparger, a microbubble generator positioned within the liquid, and a conduit between the head-space and the microbubble generator, such that gas from the head space can travel through the conduit to the microbubble generator. Also described is a method of plasma treating a liquid. The method includes the steps of positioning a liquid in a storage chamber at a volume that provides a head-space in the storage chamber, feeding a gas to a sparger that is positioned within the liquid to form a first set of bubbles in the liquid, passing the first set of bubbles between a pair of electrodes positioned within the liquid and substantially above the sparger, generating a plasma discharge between the electrodes, and feeding the gas in the head-space into a microbubble generator positioned within the liquid to form a second set of bubbles in the liquid, wherein the second set of bubbles are in the range of 0.1 to 5 microns in diameter.