Shaped Activated Carbon Array for Low-Pressure Tank Venting
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Solution Overview
Problem
Existing tank venting systems using activated carbon packings face high pressure drops and reduced adsorptive capacity due to particle size limitations, leading to inefficient hydrocarbon vapor retention in motor fuel systems, especially under vibrations during vehicle motion.
Innovation Solution
The use of an array of shaped activated carbon articles with varying channel cross-sectional areas connected to maintain low pressure drops while enhancing adsorptive capacity, produced through a process involving carbonization and activation of carbon particles with high mesopore content, resulting in a high activated carbon content of at least 95% by weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If activated carbon packings are used in tank venting systems, then adsorptive capacity is achieved, but pressure drop becomes very high
Solution Approach 1:
The patent employs monolithic structures with controlled porosity and channel networks instead of packed particles. The monolithic activated carbon articles feature an interconnected pore system that allows vapor flow while providing adsorption sites, eliminating the high pressure drop associated with particle packings while maintaining adsorptive capacity.
Solution Approach 2:
The patent changes the physical state and structural parameters of activated carbon from particulate to monolithic form. This transformation alters the flow characteristics and pressure drop profile while preserving the adsorptive properties through controlled pore distribution and surface area within the monolithic structure.
2Duration of action of stationary object
If small particle size activated carbon is used for good regenerability, then regenerability is improved, but pressure drop increases even greater
Solution Approach 1:
The monolithic structure incorporates a controlled pore network that provides adequate surface area for adsorption and regeneration cycles without requiring small particle sizes. The interconnected pores allow vapor penetration and desorption while maintaining structural integrity and low flow resistance.
3Quantity of substance
If activated carbon particles are used in moving vehicles, then adsorption function is provided, but vibrations cause particle abrasion and pulverization reducing adsorptive capacity
Solution Approach 1:
The monolithic activated carbon structure provides a rigid, continuous framework that resists vibration-induced mechanical degradation. The monolithic form eliminates inter-particle contact and abrasion while maintaining the porous adsorption network necessary for hydrocarbon vapor capture in dynamic vehicle environments.
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
This configuration achieves a significant reduction in pressure drop by up to 70% compared to conventional activated carbon packings while maintaining high adsorptive capacity, ensuring effective hydrocarbon vapor retention and mechanical stability.
Implementation Method 1
Hydrocarbons emitted by a motor fuel reservoir as a result of an increase in pressure, particularly when the motor vehicles are not in motion and are exposed, for example, to direct solar radiation in the summer months, are retained by such tank venting systems
Implementation Method 2
produced through a process involving carbonization and activation of carbon particles with high mesopore content
Implementation Method 3
carbonization and activation of carbon particles with high mesopore content, resulting in a high activated carbon content of at least 95% by weight
Data Source
AI summary
The invention relates to an array of shaped activated carbon articles having channels extending through said array of shaped activated carbon articles, wherein said array of shaped activated carbon articles includes at least two shaped monolithic activated carbon articles containing channels, which channels of the at least two shaped monolithic activated carbon articles are connected so as to communicate with each other and the free cross-sectional areas formed by the channel cross-sections thereof have different values in said first and second shaped monolithic activated carbon articles. The invention also relates to a tank venting system and a motor vehicle containing an array of shaped activated carbon articles of the invention. Finally, the invention relates to a process for the production of said array of shaped activated carbon articles of the invention.