Wet Electrostatic Gas Cleaning System with Non-Thermal Plasma for NOx Reduction
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Solution Overview
Problem
Current methods for cleaning exhaust gases from fossil fuel boilers and furnaces are inefficient in removing sub-micron particulate matter and require costly ozone generators that use purified oxygen or clean air, leading to high operating costs and incomplete pollutant reduction.
Innovation Solution
A system comprising two wet electrostatic precipitator units, where the first unit electrostatically charges and oxidizes gas components using ozone generated from the gas stream itself, and the second unit uses aqueous scrubbing to remove higher oxides and sub-micron particles down to 0.01 microns, with a packed bed for enhanced gas distribution and polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional wet scrubbers are used to remove sub-micron particles, then higher energy consumption is required, but this leads to prohibitive operating costs
Solution Approach 1:
The patent replaces conventional mechanical wet scrubbing systems with a plasma-based electrostatic precipitation system. The plasma field generates ionized particles that electrostatically charge sub-micron particles, enabling their separation without high-energy mechanical scrubbing. This substitution of mechanical energy with electrical field energy resolves the contradiction by achieving high removal efficiency without prohibitive energy consumption.
Solution Approach 2:
The invention changes the physical state of the gas stream by introducing non-thermal plasma, which creates a highly ionized environment without significant temperature increase. This parameter change enables efficient charging of sub-micron particles through electron attachment, allowing their removal via electrostatic forces rather than high-energy mechanical processes, thus maintaining high efficiency while reducing energy consumption.
2Object-generated harmful factors
If selective catalytic reduction is used for nitrogen oxides removal, then nitrogen oxides are reduced to N2 gas, but the process is expensive and subject to catalyst poisoning
Solution Approach 1:
The patent replaces catalytic chemical reduction with a plasma-based oxidation process. The non-thermal plasma generates highly reactive oxygen species that directly oxidize nitrogen oxides to higher oxides (NO2, N2O5) which are then water-soluble. This eliminates the need for catalysts entirely, avoiding catalyst poisoning issues while maintaining effective nitrogen oxides removal through a more reliable plasma-driven chemical process.
Solution Approach 2:
The invention changes the chemical pathway from reduction to oxidation by utilizing plasma-generated reactive oxygen species. Instead of reducing NOx to N2 through catalytic reactions, the plasma process oxidizes NO to NO2 and further to water-soluble higher oxides that can be removed by water scrubbing. This parameter change in reaction mechanism eliminates catalyst dependency and improves reliability.
3Object-generated harmful factors
If non-catalytic reduction is used for nitrogen oxides, then chemical reactions reduce nitrogen oxides to N2 gas, but high temperatures and large reactor volumes are required
Solution Approach 1:
The patent replaces high-temperature thermal processes with a non-thermal plasma process. The plasma generates highly reactive species through electrical field ionization rather than thermal energy, enabling nitrogen oxides oxidation at ambient or near-ambient temperatures. This substitution of thermal energy with electrical field energy resolves the contradiction by achieving effective removal without high temperature requirements.
Solution Approach 2:
The invention changes the energy input method from thermal to electrical, creating a non-thermal plasma environment where reactive oxygen species are generated through electron impact ionization. This parameter change enables the oxidation of nitrogen oxides at low temperatures, eliminating the need for high-temperature reactors while maintaining effective pollutant removal through plasma-driven chemical reactions.
4Object-generated harmful factors
If ozone generators using purified oxygen are used for oxidation, then higher oxides are formed that are more soluble in water, but the operating costs are high
Solution Approach 1:
The patent implements a self-service system where the plasma reactor directly processes the contaminated gas stream itself to generate the necessary oxidizing species. The gas stream provides the oxygen atoms needed for oxide formation through plasma-induced dissociation and recombination, eliminating the need for external purified oxygen supply. This self-service approach reduces operating costs by utilizing resources already present in the waste stream.
Solution Approach 2:
The invention makes the plasma reactor perform multiple functions simultaneously: it generates reactive oxygen species for oxidation, charges particles for electrostatic separation, and prepares higher oxides for water solubility enhancement. By consolidating these functions into a single plasma-based system rather than requiring separate ozone generation and injection equipment, the process reduces operating costs while achieving the desired oxide transformation.
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
Achieves high-efficiency removal of sub-micron particles and pollutants, reducing operating costs by utilizing oxygen from the gas stream and minimizing energy consumption, while ensuring compliance with stringent environmental regulations.
Implementation Method 1
A system and method for high efficiency cleaning of a gas stream is provided
Implementation Method 2
oxidize the gas flow so as to oxidize the mixed nitrogen oxides (NOx) and the mixed sulfur oxides (SOx) to the higher, more soluble oxides
Implementation Method 3
contacted with water. While higher oxides are reasonably soluble in water (forming acids)
Implementation Method 4
improved ozone and free radical generation devices, especially for use in the invention systems
Data Source
AI summary
An apparatus and method of generating ozone and its incorporation into a system apparatus and method of cleaning exhaust gasses from fossil fuel burning boilers and/or furnaces are disclosed.