Boiler Cleaning via Magnesium Oxide Crystallization
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Solution Overview
Problem
Boilers, especially those downstream from combustion devices, become dirty due to deposition of oxide and salt mixtures, leading to reduced efficiency and performance, and existing cleaning methods are costly, require frequent shutdowns, and can cause mechanical stress and corrosion, while current technologies fail to effectively address the molten salts and oxides responsible for dirtying.
Innovation Solution
Injecting an aqueous solution of magnesium chloride and/or sulfate and/or calcium chloride into the combustion chamber as droplets, which vaporize and decompose into small magnesium and/or calcium oxide particles that react with molten salts and oxides, increasing their melting temperature and preventing adherence to exchanger surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical cleaning devices (shot peening, striking) are used to clean boiler surfaces, then cleaning effectiveness is improved, but the lifetime of exchanger surfaces is reduced due to mechanical stresses and erosion
Solution Approach 1:
The patent replaces mechanical cleaning systems (shot peening, striking) with a chemical cleaning system that introduces powdered cleaning products into the combustion chamber. These products chemically react with and remove deposits from exchanger surfaces without imposing mechanical stresses, thereby maintaining cleaning effectiveness while preserving the lifetime of exchanger surfaces.
Solution Approach 2:
The patent changes the cleaning mechanism from mechanical to chemical by altering the fundamental parameter of interaction between the cleaning agent and deposits. Instead of using high-velocity particles or shockwaves, the system uses chemically active powdered substances that react with deposits at lower energies, eliminating the erosive effects while maintaining cleaning capability.
2Reliability
If explosion techniques are used to clean boilers, then cleaning effectiveness is improved, but operational safety deteriorates due to risks for operators handling explosive gases
Solution Approach 1:
The patent replaces the explosive cleaning method with a chemical reaction-based cleaning system. Instead of using explosive gases to physically detach deposits, the system introduces powdered cleaning products that chemically interact with and remove deposits through controlled reactions in the combustion chamber, eliminating the safety hazards associated with explosive material handling while maintaining cleaning effectiveness.
Solution Approach 2:
The patent introduces powdered cleaning products as an intermediary substance that mediates the cleaning process. These products serve as a safe alternative to explosive gases, providing the necessary cleaning action through chemical reactions without posing safety risks to operators. The powdered substances act as a controlled intermediary between the combustion process and deposit removal.
3Reliability
If steam injection is used for cleaning, then cleaning effectiveness is improved, but net steam production performance deteriorates and mechanical wear problems occur
Solution Approach 1:
The patent replaces steam injection with a powdered substance-based chemical cleaning system. Instead of introducing additional steam that competes with the boiler's steam production function, the system uses dry powdered cleaning products that chemically remove deposits without affecting the steam generation process, thereby maintaining cleaning effectiveness while preserving net steam production performance and avoiding mechanical wear from moisture.
4Reliability
If steam injection is used for cleaning, then cleaning effectiveness is improved, but corrosion phenomena occur in cold parts of the boiler due to increased acid dew point
Solution Approach 1:
The patent replaces steam injection with a powdered chemical cleaning system that does not introduce additional moisture or affect the acid dew point. The powdered substances chemically interact with deposits through dry reactions, eliminating the corrosion mechanism associated with increased moisture content in the flue gases, thereby maintaining cleaning effectiveness while preventing corrosion in cold boiler parts.
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
Significantly reduces the need for frequent boiler shutdowns, improves efficiency by controlling dirtying, and limits corrosion by increasing the melting temperature of molten salts and oxides, thus extending the lifespan of exchanger surfaces.
Implementation Method 1
by vaporization of the water of the aqueous solution
Implementation Method 2
then thermal decomposition, are transformed in the combustion chamber into magnesium and/or calcium oxide particles
Implementation Method 3
reacting in the combustion chamber by mixing with molten salts and/or molten oxides, present in the fumes, to crystallize these molten salts and/or to vitrify these molten oxides
Implementation Method 4
to crystallize these molten salts
Implementation Method 5
to vitrify these molten oxides
Data Source
AI summary
Disclosed is a process for cleaning a boiler, wherein, while fumes are emitted in a combustion chamber of the boiler and circulate up to exchangers of the boiler, an aqueous solution of dissolved magnesium chloride and/or sulfate and/or dissolved calcium chloride is injected into the combustion chamber in the form of droplets which, by vaporization of the water of the aqueous solution, then thermal decomposition, are transformed in the combustion chamber into magnesium and/or calcium oxide particles reacting in the combustion chamber by mixing with molten salts and/or molten oxides, present in the fumes, to crystallize these molten salts and/or to vitrify these molten oxides before these molten salts and/or these molten oxides come into contact with the exchangers. Also disclosed is a device for implementing this process and a boiler equipped with this device.