Sulfur-Modified Carbon Sorbent Ignition Risk
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Solution Overview
Problem
Existing sorbents for cleaning exhaust gases from thermal processes either have high adsorption capacity for heavy metals like mercury but low for organic pollutants, or vice versa, and often exhibit a high tendency to ignite when mixed with catalytically active process dust, reducing their effectiveness and safety.
Innovation Solution
A carbon-containing, powdery or granular sorbent modified with sulfur and/or sulfur compounds, specifically impregnated with an aqueous sulfur-containing solution under controlled conditions to achieve a balanced specific surface area to pore volume ratio, reducing ignition tendency while maintaining adsorption capacity for both mercury and organic pollutants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lignite coke dust is used as sorbent for exhaust gas cleaning, then adsorption capacity for heavy metals like mercury is improved, but tendency to ignite increases
Solution Approach 1:
Sulfur compounds are introduced as an intermediary substance that modifies the surface properties of lignite coke. The sulfur compounds act as a mediator between the carbon structure and the exhaust gas components, forming sulfur-containing surface groups that reduce ignition tendency while preserving heavy metal adsorption capacity through controlled surface chemistry modifications.
Solution Approach 2:
The chemical composition and surface properties of the lignite coke are modified by changing the sulfur content parameter. By controlling the sulfur modification process, the surface chemistry is altered to create a balance where heavy metal adsorption sites are preserved while ignition-promoting surface groups are reduced or transformed.
2Object-affected harmful factors
If zeolite is added to lignite coke dust for inerting, then ignition tendency is reduced, but adsorption capacity for organic pollutants decreases
Solution Approach 1:
Instead of uniformly modifying the entire sorbent mass, sulfur modification is applied locally at the surface level where it is most needed for ignition prevention. This localized surface treatment allows the bulk carbon structure to maintain its organic pollutant adsorption capacity while the surface layer provides ignition resistance through sulfur-containing functional groups.
3Object-affected harmful factors
If sulfur is added to carbon adsorbents to reduce ignition tendency, then safety is improved, but adsorption capacity for organic compounds decreases
Solution Approach 1:
The sulfur content and distribution within the carbon adsorbent are carefully controlled as a key parameter. By optimizing the sulfur modification conditions (temperature, time, sulfur compound type), the surface chemistry is tuned to achieve the minimum necessary sulfur content for ignition prevention while preserving sufficient organic compound adsorption sites.
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 sorbent achieves a reduced tendency to ignite while maintaining high adsorption capacities for both elemental mercury and organic pollutants like polyhalogenated dibenzodioxins and dibenzofurans, with improved separation efficiency and safety in industrial applications.
Implementation Method 1
The invention further relates to a method for producing a carbon-containing sorbent for dry exhaust gas purification, comprising the impregnation of carbons from the group of lignite with an aqueous sulfur-containing solution
Implementation Method 2
Carbon adsorbents are used in particular to clean exhaust gases from metallurgical/secondary metallurgical processes. Exhaust gases from these processes contain polyhalogenated dibenzodioxins and dibenzofurans as well as heavy metals, especially mercury
Data Source
AI summary
The invention relates to a carbon-containing, powdered or granular sorbent for the dry purification of exhaust gases from thermal processes. The sorbent comprises carbon adsorbents from the group of activated carbon and/or lignite cokes, which are modified or doped with sulfur and/or sulfur compounds. The sorbent is characterized in that the specific surface area of the carbon adsorbents in m²/g, based on the pore volume of the micropores in cm³/g, is between 2,400 and 2,700.