Ozone Oxidation and Wet ESP for Regional Haze Compliance
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Solution Overview
Problem
Existing air pollution control technologies are ineffective in removing ultra-fine particulate matter and condensation formation products from combustion processes, exacerbated by the use of ammonia as a reductant, leading to non-compliance with stringent emission regulations such as the US EPA Regional Haze Rules and increased formation of regional haze.
Innovation Solution
A multi-stage gas flow treatment system utilizing ozone (O3) to oxidize nitrogen oxides (NO) to N2O5 and mercury to its oxidized form, followed by a two-stage wet electrostatic precipitator (ESP) for enhanced particulate removal, eliminating the need for ammonia-based systems and integrating with existing combustion systems without disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional air pollution control technologies (interception and impaction) are used, then general particulate matter removal is achieved, but ultra-fine particulate matter and condensation formation products cannot be effectively removed
Solution Approach 1:
The patent changes the physical-chemical parameters of the gas stream by introducing ozone to oxidize nitrogen oxides to water-soluble forms and converting mercury to oxidized species. This parameter transformation enables subsequent effective removal of ultra-fine particles through wet electrostatic precipitation, which conventional dry methods cannot achieve.
Solution Approach 2:
The patent employs ozone as a strong oxidant to accelerate the oxidation of nitrogen oxides and mercury compounds. This accelerated oxidation converts difficult-to-remove ultra-fine particulate matter and gaseous pollutants into water-soluble forms that can be efficiently captured by the wet electrostatic precipitator.
2Object-generated harmful factors
If ammonia is used as a reductant for NOx reduction, then nitrogen oxide emissions are reduced, but visual clarity in Class I areas deteriorates due to carryover products and condensation formation
Solution Approach 1:
The patent converts the harmful effect of nitrogen oxides into a beneficial process by using ozone to oxidize them to water-soluble forms that can be captured. This eliminates the need for ammonia-based reduction systems that cause visual clarity problems, while still achieving effective NOx control.
Solution Approach 2:
The patent introduces ozone as an intermediary substance that mediates between the combustion exhaust and the final cleaned gas stream. Ozone oxidizes nitrogen oxides and mercury compounds, enabling their removal without requiring ammonia, thus preserving visual clarity in Class I areas.
3Object-generated harmful factors
If existing combustion systems are modified to meet stringent emission regulations, then compliance with Regional Haze Rules is achieved, but system complexity and operational disruption increase
Solution Approach 1:
The patent segments the emission control process into distinct functional stages: ozone oxidation stage, wet electrostatic precipitation stage, and CO2 scrubbing stage. This segmentation allows each component to be optimized independently and facilitates easier integration with existing combustion systems compared to monolithic solutions.
Solution Approach 2:
The patent creates a multi-functional treatment system where the wet electrostatic precipitator handles multiple pollutants (oxidized nitrogen oxides, mercury, ultra-fine particles) simultaneously, and the CO2 scrubber operates efficiently with the cleaned gas stream. This multi-functionality reduces overall system complexity compared to separate dedicated systems for each pollutant.
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
Effectively reduces emissions of nitrogen oxides, mercury, and particulate matter, enabling compliance with stringent regulations while minimizing operational disruptions and health risks associated with ammonia use, and improving the efficiency of CO2 scrubbers.
Implementation Method 1
injection of ozone (O3) as a reactant to oxidize nitric oxide (NO, the predominant form of nitrogen oxide in most flue gases) to N2O5 and convert mercury to its oxidized form
Implementation Method 2
exposing the gas flow to one or more stages of an electrostatic precipitator (ESP) to remove particulate matter from the gas flow
Data Source
AI summary
A method for cleaning gas flows generated by a combustion process. In one where continued use of coal as a source of heat input embodiment, this is accomplished by a multi-stage gas flow treatment that comprises treatment of a gas flow with ozone as a reactant to oxidize nitrous oxide and convert mercury to its oxidized form. This is followed by exposing the gas flow to one or more stages of a wet electrostatic precipitator (ESP) to substantially remove water and particulate matter from the gas flow. Among other benefits, the disclosed treatment process assists States to comply with regional haze reduction rules and regulations.