Sulphate Sludge Injection for Barium Fixation in Power Plant Filter Ash
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Solution Overview
Problem
Existing methods for reducing the soluble barium content in filter ash from power plants are not economically justifiable, leading to environmental risks and increased disposal costs due to high barium levels in the eluate.
Innovation Solution
Incorporating a pumpable, sulphate-containing sludge into the coal combustion process, where sulphate forms a chemical bond with barium to produce poorly soluble barium sulfate, reducing the elutable barium content in filter ash and preventing groundwater contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aging fly ash under carbon dioxide is used to reduce barium content, then soluble barium is reduced, but the process requires unjustifiable time and incurs high economic costs
Solution Approach 1:
The invention changes the chemical parameters by introducing sulphate-containing substances (gypsum, calcium sulphate, barium sulphate) that directly react with barium compounds to form insoluble barium sulphate, replacing the slow aging process with a rapid chemical precipitation process that reduces soluble barium without requiring extended time
Solution Approach 2:
The invention extracts and removes soluble barium compounds from filter ash by adding sulphate substances that precipitate barium as insoluble barium sulphate, which can then be separated through washing and filtration processes, directly eliminating the harmful soluble barium without time-consuming aging
2Object-affected harmful factors
If aging fly ash under carbon dioxide is used to reduce barium content, then soluble barium is reduced, but economic costs increase significantly
Solution Approach 1:
The invention utilizes substances already present in the power plant system (gypsum from flue gas desulfurization, calcium sulphate from water treatment) and redirects them to treat filter ash barium contamination, eliminating the need for external chemicals or prolonged aging processes and reducing overall operational costs
Solution Approach 2:
The invention recovers useful substances (sulphate-containing gypsum and calcium sulphate) that would otherwise be discarded or require separate disposal, and repurposes them to treat barium contamination in filter ash, transforming waste management into a cost-saving process
3Object-affected harmful factors
If filter ash with high barium content is disposed of, then disposal costs increase and landfill options are limited, but recycling becomes difficult
Solution Approach 1:
The invention performs preliminary treatment of filter ash by adding sulphate substances before disposal or recycling, converting soluble barium to insoluble barium sulphate in advance, which ensures that the ash meets disposal requirements or is suitable for recycling without requiring costly or time-consuming subsequent treatments
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
The method effectively reduces soluble barium in filter ash, allowing for harmless classification and recycling or disposal, improving gypsum quality and reducing logistical and economic burdens on power plants.
Implementation Method 1
sulphate forms a chemical bond with barium to produce poorly soluble barium sulfate
Implementation Method 2
produce poorly soluble barium sulfate, reducing the elutable barium content
Implementation Method 3
the coal dust is burned in the combustion chamber, the resulting heat generates steam
Implementation Method 4
the flue gas is filtered in the filter device, with filter ash occurring as waste product
Data Source
Figure 1
AI summary
The invention relates to a combustion process in a power plant comprising at least one mill, a steam generator with a combustion chamber connected to the at least one mill, and a flue gas cleaning system downstream of the steam generator, which comprises at least one filter device and a flue gas desulfurization system downstream of the filter device, wherein raw coal is ground into coal dust in the at least one mill, the coal dust is burned in the combustion chamber, steam is generated in the steam generator by the heat produced in the process, and the flue gas produced in the combustion chamber is directed into the flue gas cleaning system, where the flue gas is filtered in the filter device, with filter ash being produced as a by-product, and sulfur and/or at least one sulfur compound is separated from the filtered flue gas in the flue gas desulfurization system.To reduce the soluble barium content in the filter ash, a pumpable, sulfate-containing sludge and/or a sulfate-containing model suspension is fed to at least one mill in the process, ground therein together with the raw coal, fed to the combustion chamber and burned with the coal dust.