Microporous Carbon Sorbent for Gas Storage
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Solution Overview
Problem
Current gas storage technologies face limitations such as high weight-to-volume ratios, safety concerns with pressurized containers, and low energy density, particularly for hazardous gases like hydrogen and hydrocarbons, which hinder their widespread adoption in transportation and spacecraft propulsion.
Innovation Solution
A method for producing high-capacity microporous carbon sorbents through sequential steps including carbonization, activation using cyclic chemisorption-desorption techniques, heat-treatment, and surface conditioning with reducing gases to optimize pore structure and gas storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If compressed gas systems are used for gas storage, then gas storage capacity is improved, but weight-to-volume ratio increases due to heavy containers
Solution Approach 1:
The patent employs activated carbon and other porous sorbent materials with highly developed nanostructures to adsorb gas molecules. The porous structure provides large internal surface area for gas adsorption, achieving high storage capacity without the need for heavy pressurized containers. The sorbent material itself becomes the storage medium, eliminating the weight penalty of thick-walled pressure vessels.
Solution Approach 2:
The patent develops composite sorbent materials combining carbon-based materials with other substances to enhance gas storage capacity and selectivity. These composite structures optimize both the adsorption capacity and the mechanical properties, providing lightweight alternatives to traditional metal pressure containers while maintaining high gas storage densities.
2Quantity of substance
If pressurized containers are used for storing hazardous gases, then gas storage capacity is improved, but safety concerns increase due to accidental tank rupture risks
Solution Approach 1:
The porous sorbent materials adsorb hazardous gas molecules within their internal pore structures, confining the gas in a distributed manner throughout the solid matrix rather than storing it under pressure in a single container. This eliminates the risk of catastrophic tank rupture while maintaining high storage capacity through the large internal surface area of the porous structure.
Solution Approach 2:
The patent creates a safe storage environment by immobilizing hazardous gases through strong adsorption interactions with the sorbent material. The gas molecules are held in place by physical and chemical interactions with the porous structure, effectively creating an inertified state that prevents accidental release even under conditions that would normally cause pressure vessel failure.
3Quantity of substance
If cryogenic storage is used for gas storage, then gas storage capacity is improved, but energy consumption increases due to liquefaction and maintenance requirements
Solution Approach 1:
Instead of changing the thermal state of the gas to liquid form through cryogenic temperatures, the patent changes the phase interaction by utilizing adsorption at moderate temperatures. The gas remains in the gas phase but is concentrated through adsorption onto the porous sorbent surface, achieving high density storage without the energy-intensive cooling and liquefaction processes required by cryogenic methods.
4Quantity of substance
If metal hydrides are used for hydrogen storage, then gas storage capacity is improved, but temperature requirements increase for hydrogen liberation
Solution Approach 1:
The patent uses porous carbon-based sorbent materials to adsorb hydrogen molecules on their internal surfaces. This physical adsorption mechanism allows hydrogen to be stored at high capacities without forming chemical bonds that would require high temperatures for release. The hydrogen can be liberated simply by heating the sorbent to moderate temperatures or by reducing the partial pressure, avoiding the high-temperature requirements of metal hydride decomposition.
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 method results in sorbents with enhanced gas storage capacity, safety, and diffusivity, specifically suitable for gases like PH3, BF3, and H2, offering improved energy density and reduced volume requirements.
Implementation Method 1
Gas storage based on adsorption on activated carbon offers large storage capacity in terms of weight (2-4 times greater than state-of-the-art hydrides). The high density of gas at the surface more than compensates some loss of the available volume associated with the introduction of a sorbent.
Implementation Method 2
activation of the carbonized material using any method, but preferably a cyclic chemisorption-desorption technique which consists of the following steps, repeated cyclically, as necessary, until an optimum gas-storage capacity is reached: (i) oxygen chemisorption on carbon surface at a relatively low temperature Tch for a period of τch to form stable oxygen surface complexes; and (ii) desorption of the surface complexes at a high-temperature, Td, in the absence of oxygen for a period τd
Implementation Method 3
heat-treatment at elevated temperatures (about 800° C. to about 2,000° C.)
Implementation Method 4
surface conditioning by hydrogen, or other reducing gas, e.g. carbon monoxide, treatment at elevated temperatures (above about 300° C.)
Data Source
AI summary
The method enables control over carbon pore structure to provide sorbents that are particularly advantageous for the adsorption of specific gases. It involves preparation of a sorbent precursor material, carbonization of the precursor material, and, usually, activation of the carbonized material. The resultant material is subjected to heat treatment and/or to surface conditioning by a reducing gas at elevated temperatures.