SO3 Removal via Salt Spray in Flue Gas
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Solution Overview
Problem
Existing exhaust gas treatment systems face challenges in effectively and economically removing sulfur trioxide (SO3) from combustion exhaust gases, as they often require expensive chemicals, lead to corrosion, and have limitations in achieving low enough concentrations to meet environmental standards.
Innovation Solution
An exhaust gas treatment system that sprays an aqueous solution containing dissolved salts of Na, K, Mg, or Ca into the flue, utilizing a two-fluid nozzle to atomize the solution and create fine particles that adsorb and immobilize SO3, thereby reducing its concentration without the need for expensive chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ammonia gas is injected into combustion exhaust gas to remove SO3, then SO3 removal is achieved, but facility cost and operation cost increase due to separate heavy metal treatment
Solution Approach 1:
The invention changes the chemical parameter by using sodium chloride solution instead of ammonia gas, which fundamentally alters the reaction products from ammonium sulfate (requiring separate heavy metal treatment) to sodium sulfate (easily soluble and treatable in existing wet desulfurization systems), thereby reducing facility complexity and cost
Solution Approach 2:
The invention makes the existing wet desulfurization system serve dual purposes by having it treat both SO2 and the reaction products from SO3 removal, eliminating the need for separate treatment facilities and reducing overall system complexity
2Object-affected harmful factors
If ammonia gas is constantly supplied to remove SO3, then SO3 removal is maintained, but operation cost increases due to large ammonia consumption
Solution Approach 1:
The invention replaces expensive ammonia gas with cheap sodium chloride solution, which can be readily obtained from desulfurization effluents, significantly reducing operation costs while maintaining effective SO3 removal
Solution Approach 2:
The invention recovers and utilizes sodium chloride from desulfurization effluents as the reagent for SO3 removal, turning a waste stream into a valuable resource and eliminating the need for continuous purchase of expensive ammonia gas
3Object-affected harmful factors
If wet electrostatic precipitator or dielectric flue gas treatment system is used to remove dust and SO3, then dust removal is achieved, but SO3 removal is insufficient for highly concentrated cases
Solution Approach 1:
The invention performs preliminary chemical reaction by injecting sodium chloride solution to convert SO3 into sodium sulfate particles before the gas reaches the electrostatic precipitator, enhancing the subsequent dust collection efficiency and ensuring reliable SO3 removal even for highly concentrated cases
Solution Approach 2:
The invention creates composite particles by having sodium sulfate formed on dust particle surfaces, which are then more effectively captured by the electrostatic precipitator, improving overall SO3 removal reliability
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 allows for efficient and cost-effective removal of SO3, preventing corrosion and simplifying treatment processes by using readily available salts, such as Na2SO4 and MgSO4, which are easily obtained from desulfurization effluents, thereby reducing operational and facility costs.
Implementation Method 1
spraying an aqueous solution that contains a dissolved salt of a chloride of any one of Na, K, Mg, and Ca or a sulfate of any one of K and Mg, into a flue through which the combustion exhaust gas flows
Data Source
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AI summary
An exhaust gas treatment system is provided that can sufficiently remove pollutants such as SO3 contained in combustion exhaust gas at low cost. In the exhaust gas treatment system for removing pollutants such as SO3 contained in combustion exhaust gas, there is provided dissolved salt aqueous solution sprays 35A, 35B, and 35C, that spray an Na2SO4 aqueous solution obtained from desulfurization effluent of a wet desulfurization system, into a flue though which the combustion exhaust gas flows.