Macroporous Calcium Hydroxide Adsorbent for Emergency SO2 Retention
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Solution Overview
Problem
Existing adsorbent materials are inadequate for efficiently retaining high concentrations of sulfur dioxide (SO2) in emergency emissions from copper smelters, particularly during power outages, due to limitations in mechanical strength, diffusional limitations, and retention capacity under high-flow, high-temperature conditions.
Innovation Solution
A shaped adsorbent material composed of calcium hydroxide, sodium bicarbonate, potassium bicarbonate, and sepiolite, optimized for high mechanical strength and macroporosity, is used in a fixed bed system to capture SO2 efficiently under emergency conditions, forming CaSO3 on the surface and minimizing diffusional limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional adsorbent materials are used for SO2 retention, then the system can operate under normal conditions, but the retention capacity is insufficient for high-concentration emergency emissions
Solution Approach 1:
The patent uses a composite material consisting of calcium hydroxide (active component for SO2 reaction), sepiolite (porous structure provider), and sodium bicarbonate (mechanical strength enhancer). This composite structure combines the high reactivity of calcium hydroxide with the macroporous architecture of sepiolite, achieving both high retention capacity and reliable performance under emergency high-flow conditions
Solution Approach 2:
The invention utilizes sepiolite, a natural porous clay mineral, to create a macroporous structure with pore sizes of 0.03-10 μm. This porous architecture provides high surface area for SO2 adsorption and facilitates rapid gas diffusion, enabling the material to handle high-concentration emergency emissions effectively
2Productivity
If the adsorbent material has high porosity to reduce diffusional limitations, then gas diffusion improves, but mechanical strength decreases
Solution Approach 1:
The patent creates a composite where sepiolite provides the macroporous structure for rapid gas diffusion, while sodium bicarbonate acts as a binding agent to maintain mechanical integrity. The synergistic combination allows the material to simultaneously achieve high porosity (0.2-2.0 mL/g) and adequate mechanical strength for industrial application
Solution Approach 2:
The invention optimizes the pore size parameter to 0.03-10 μm range, which balances diffusional efficiency with structural stability. This specific pore size range allows rapid SO2 diffusion while maintaining sufficient mechanical strength, resolving the contradiction between productivity and strength
3Quantity of substance
If calcium hydroxide is used as the primary adsorbent, then SO2 reaction capacity increases, but the material lacks mechanical consistency
Solution Approach 1:
The patent formulates a composite where calcium hydroxide (5-50 wt%) provides high SO2 reaction capacity, sepiolite (40-80 wt%) provides structural consistency and porosity, and sodium bicarbonate (5-20 wt%) enhances mechanical strength. This multi-component composite resolves the mechanical weakness of pure calcium hydroxide while preserving its high reactivity
Solution Approach 2:
Sepiolite acts as an intermediary material that provides structural framework and mechanical consistency to the calcium hydroxide particles. The sepiolite network holds the calcium hydroxide in place, preventing particle disintegration while allowing SO2 to access the reactive calcium hydroxide surfaces
4Loss of time
If the emergency system activates immediately, then SO2 release is prevented, but the system requires rapid response capability that conventional systems lack
Solution Approach 1:
The macroporous structure of sepiolite with pore sizes of 0.03-10 μm enables rapid gas diffusion and immediate SO2 uptake upon system activation. The high porosity (0.2-2.0 mL/g) ensures that SO2 molecules can quickly penetrate the adsorbent bed, achieving effective retention within seconds of emergency activation
Solution Approach 2:
The invention optimizes the particle size and pore distribution parameters to maximize diffusion rates. The specific surface area is maintained between 1-20 m²/g, and pore sizes are controlled at 0.03-10 μm, creating optimal conditions for rapid gas-phase SO2 diffusion and reaction, enabling immediate response capability
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 material achieves greater than 99% SO2 retention for extended periods, reducing emissions below 1000 mg/Nm3 and minimizing air quality issues, with a retention capacity exceeding 300 mg SO2 per gram of adsorbent.
Implementation Method 1
calcium hydroxide, which reacts with SO2 to form CaSO3
Implementation Method 2
which is adsorbed with high efficiency on the surface due to the existence of a macroporous structure
Data Source
Figure 1A~1C
Figure 2~4
Figure 5A~5B
AI summary
The present invention relates to an adsorbent material with high capacity for retaining SO2 present in high concentrations in high flow gaseous streams, and its particular use in the elimination of SO2 in emergency point emissions of copper factories. This material comprises calcium hydroxide as an acidic gas adsorbent element, together with sepiolite as a binding agent and sodium and potassium bicarbonates as basifying elements and may be obtained by an easy process which requires mainly a dry treatment at temperatures below 60ºC.