Ozonation-Based Dry Desulfurization for Cementitious Material Production
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Solution Overview
Problem
Existing methods for producing cementitious materials from flue gas desulfurization and denitrification by-products are inefficient, requiring large water and steam consumption, and are not sustainable, especially in arid areas, and struggle to stabilize magnesium sulfate content.
Innovation Solution
An ozonation-based method that mixes flue gas with an ozone-containing gas for dry desulfurization and denitrification using a powdered desulfurizing agent containing magnesium oxide and a catalyst, generating by-products which are then mixed with fly ash and additives to produce a cementitious material, reducing water and steam consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet type process is adopted for flue gas desulfurization and denitrification, then desulfurization and denitrification effects are achieved, but large amount of industrial waste liquid is produced and water consumption increases
Solution Approach 1:
The patent changes the physical state parameter of the process from wet type to dry type, eliminating the need for large amounts of water while maintaining desulfurization and denitrification effectiveness. The dry process converts gaseous pollutants into solid by-products that can be directly utilized.
Solution Approach 2:
The patent converts harmful gaseous pollutants (SO2, NOx) into beneficial solid by-products (calcium sulfate, calcium nitrate) that can be used as cementitious materials, transforming environmental hazards into valuable resources.
2Reliability
If conventional desulfurization method is used, then sulfur dioxide removal is achieved, but magnesium sulfate content cannot be stabilized and requires additional concentration steps
Solution Approach 1:
The patent optimizes reaction parameters including temperature control (40-80°C), pH control (5.5-6.5), and molar ratios of reactants to stabilize the magnesium sulfate content in the by-product, eliminating the need for additional concentration steps.
Solution Approach 2:
The patent implements pH monitoring and adjustment during the reaction process to maintain optimal conditions for magnesium sulfate formation, ensuring stable by-product composition through real-time process control.
3Reliability
If ozone is used for denitrification in high-temperature environment, then nitrogen oxide oxidation occurs, but ozone decomposes easily resulting in excessive ozone consumption
Solution Approach 1:
The patent controls the reaction temperature between 40-80°C, avoiding high temperatures that cause ozone decomposition. This temperature optimization maintains ozone stability while ensuring sufficient activation for nitrogen oxide oxidation.
Solution Approach 2:
The patent performs preliminary cooling of the flue gas before introducing it to the ozone reaction zone, ensuring the gas temperature is within the optimal range for ozone stability before the oxidation reaction begins.
4Quantity of substance
If evaporation, crystallization and dryness process is used to generate MgSO4, then magnesium sulfate production is achieved, but large amount of steam is consumed increasing operating cost
Solution Approach 1:
The patent maintains the reaction temperature between 40-80°C and controls humidity to directly produce solid by-products in a dry state, eliminating the need for energy-intensive evaporation, crystallization, and dryness processes.
Solution Approach 2:
The patent replaces the thermal energy-intensive evaporation and drying processes with a controlled chemical reaction system that directly produces solid by-products, substituting mechanical/thermal separation with chemical 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
This method effectively removes sulfur dioxide and nitrogen oxides, reduces resource and energy consumption, and allows for sustainable use of by-products, achieving higher desulfurization and denitrification rates with lower ozone usage.
Implementation Method 1
oxidizing NO in a flue gas with O3 to high-valent NOX
Implementation Method 2
The accumulated magnesium sulfite would undergo a redox reaction with the high-valent NOX to form nitrite and sulfate
Implementation Method 3
the magnesium oxide slurry would first absorb SO2 in the flue gas by reacting with it to generate magnesium sulfite
Implementation Method 4
the desulfurizing and denitrificating agent contains magnesium oxide and a catalyst
Data Source
AI summary
An ozonation-based method for producing a cementitious material comprises the steps of: (1) mixing a flue gas with an ozone-containing gas to form a mixed flue gas; and introducing the mixed flue gas into an absorption tower, where the mixed flue gas undergoes dry desulfurization and denitrification by reacting with a powdered desulfurizing and denitrificating agent and becomes a treated flue gas; (2) subjecting the treated flue gas to dust removal to generate by-products; and (3) uniformly mixing raw materials that comprise the first by-product, magnesium oxide, fly ash and an additive to give a cementitious material, wherein on the basis of 100 parts by weight of the cementitious material, the first by-product is 20-60 parts by weight, magnesium oxide is 16-33 parts by weight, the fly ash is 15-35 parts by weight, and the additive is 1-15 parts by weight.