Activated Carbon from Wood and Vegetable Shells
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Solution Overview
Problem
Existing activated carbons for gas-phase vapor recovery applications face limitations in achieving high density, high adsorption capacity, low pressure drop, and long lifespan due to their low density and high mesoporosity, which results in increased bleeding and reduced effectiveness over time, especially under stringent environmental regulations requiring higher vapor capture volumes.
Innovation Solution
A chemically activated carbon is produced using a combination of wood particles and comminuted carbonaceous vegetable materials, such as kernel or shell materials, in specific weight ratios, with phosphoric acid or zinc chloride as the activating agent, eliminating the need for a separate plasticization step and resulting in high-density, low-attrition extrudates with enhanced adsorptive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If chemically activated carbon is produced with high mesoporosity to increase adsorption capacity, then adsorption capacity is improved, but density decreases and pressure drop increases
Solution Approach 1:
The patent applies parameter changes by controlling the activation process to optimize the balance between mesoporosity and density. By adjusting activation conditions and using specific carbonaceous materials, the invention achieves high adsorption capacity while maintaining sufficient density to reduce pressure drop in the carbon bed.
Solution Approach 2:
The invention uses composite materials by combining different carbonaceous materials (such as coconut shell, wood, or agricultural waste) with specific activators to create a carbon product that simultaneously achieves high mesoporosity for adsorption and controlled density for structural integrity and low pressure drop.
2Quantity of substance
If conventional chemically activated carbon is produced with high mesoporosity, then adsorption capacity is improved, but bleeding increases and lifespan decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the activation process parameters (temperature, time, activator concentration) to create a pore structure that maintains adsorption capacity while reducing bleeding. This controlled activation prevents excessive mesoporosity that would lead to high bleeding and reduced lifespan.
Solution Approach 2:
The invention applies local quality by creating different pore size distributions within the carbon structure. By having a controlled mix of micropores and mesopores in specific proportions, the carbon achieves high adsorption capacity in the micropores while the mesopores provide structural stability to reduce bleeding and extend lifespan.
3Stress or pressure
If particle size is increased to reduce pressure drop, then pressure drop is reduced, but adsorption and desorption rate decrease
Solution Approach 1:
The patent applies parameter changes by optimizing particle size parameters to achieve the optimal balance between pressure drop and adsorption/desorption rate. By controlling particle size distribution and morphology during the formation process, the invention minimizes pressure drop while maintaining fast mass transfer rates through controlled internal pore structures.
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 process yields activated carbon with improved working capacity, reduced bleeding, and extended lifespan, suitable for high-volume vapor capture while maintaining cost-effectiveness and process flexibility, meeting stringent environmental standards for fuel vapor recovery.
Implementation Method 1
chemical activation to produce carbon of high density, low pressure drop, high hardness, low attrition and high activity
Implementation Method 2
molecules of impurities in the gas are adsorbed onto the surface of the activated carbon
Data Source
AI summary
The invention is directed to a chemically activated carbon, based on a combination of wood particles and comminuted carbonaceous vegetable material selected from kernel or shell material, in a weight ratio of between 5- 95 to 90-10, preferably between 15-85 and 90-10, further optionally containing a binder, said carbon having been chemically activated using phosphoric acid or zinc chloride and to a process for producing same.