Spherical Activated Carbon Composition for Low-Dust High-Hardness Adsorption
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Solution Overview
Problem
Existing granular activated carbons (GACs) produced from low-rank coal or cellulosic materials lack sufficient mechanical hardness and exhibit high dustiness, making them unsuitable for efficient contaminant removal in industrial applications.
Innovation Solution
A process involving homogenization, spheronization, thermal charring, and steam activation of a carbonaceous feed material to produce spherical granular activated carbon with high sphericity, aspect ratio, and enhanced adsorptive properties, including a BET surface area of at least 900 m2/g and specific contaminant capacities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GAC is produced from low-rank coal or cellulosic materials, then production cost is reduced, but mechanical hardness is insufficient and dustiness increases
Solution Approach 1:
The patent applies composite materials by combining low-rank coal or cellulosic materials with specific binders (such as starch, cellulose, or polyvinyl alcohol) and additives during the granulation process. This composite approach allows the use of cheaper raw materials while the binders provide structural integrity to achieve desired mechanical hardness and reduce dustiness.
Solution Approach 2:
The patent employs parameter changes by modifying process parameters such as granulation method (e.g., spheronization), drying conditions, and thermal activation parameters. These parameter adjustments transform the physical and chemical properties of the activated carbon to enhance mechanical strength and reduce dustiness while maintaining cost-effectiveness.
2Productivity
If GAC particles are made larger for high flowrate applications, then pressure drop is reduced, but particle strength and hardness decrease
Solution Approach 1:
The patent applies segmentation by creating multi-layered or composite particle structures where smaller, stronger units are aggregated into larger particles. This allows the particle to achieve both large size for low pressure drop and internal structural integrity for strength.
Solution Approach 2:
The patent uses composite materials with binders and strengthening agents incorporated into the particle matrix. These composite structures enable larger particles to maintain high strength and hardness, resolving the contradiction between particle size and mechanical properties.
3Reliability
If activation time is increased to enhance adsorptive properties, then contaminant removal efficiency improves, but production time and energy consumption increase
Solution Approach 1:
The patent applies parameter changes by optimizing activation temperature, time, and atmosphere (e.g., using steam or CO2). By adjusting these parameters, the patent achieves enhanced adsorptive properties in shorter times, reducing both production time and energy consumption while maintaining reliability.
Solution Approach 2:
The patent uses strong oxidizing agents or accelerated oxidation processes during activation to rapidly develop the porous structure and adsorptive properties. This accelerates the activation process, reducing the time and energy required while achieving the desired contaminant removal efficiency.
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 resulting spherical GAC exhibits improved mechanical integrity, reduced dustiness, faster adsorption kinetics, and enhanced contaminant removal efficiency for VOCs, PFAS, and other pollutants in gas and liquid streams, with lower energy consumption and reduced pressure drop.
Implementation Method 1
thermal charring, and steam activation of a carbonaceous feed material to produce spherical granular activated carbon
Implementation Method 2
thermal charring, and steam activation of a carbonaceous feed material
Implementation Method 3
enhanced adsorptive properties, including a BET surface area of at least 900 m2/g and specific contaminant capacities
Data Source
AI summary
A sorbent composition comprises primarily activated carbon with at least most of the particulates of the sorbent composition having a mean and/or median sphericity in the range of from about 0.75 to about 1.0, a total pore volume ranging from about 0.5 to about 0.95 cc/g, a pore volume for pores less than 500 Å ranging from about 0.6 to about 0.8 cc/g, and a BET surface area of at least about 900 m2/g, and one or more of a butane activity (measured by ASTM Method D5742) of more than about 20 wt % and a butane working capacity (measured by ASTM Method D5228) of at least about 5 wt %.