Carbon Sorbent Formulations for CO2 Capture Amid Water Vapor
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Solution Overview
Problem
Existing carbon capture technologies for CO2 separation are energy-intensive, costly, and lack selectivity for CO2 capture from gas streams containing water vapor, particularly in post-combustion gases.
Innovation Solution
A carbon sorbent formulation with a high carbon, nitrogen, and oxygen content, including pyridone and pyrrole structures, is developed for selective CO2 adsorption, featuring a high CO2 capacity and selectivity relative to water vapor, formed by mixing carbohydrates, corn starch, and amino acids, followed by carbonization and activation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional CO2 separation methods (chemical absorption, physical absorption, membrane separation, cryogenic methods) are used, then CO2 can be removed from gas streams, but the process becomes energy intensive and costly
Solution Approach 1:
The patent employs porous carbon sorbent materials with specific surface area and pore structure to enable physical adsorption of CO2. The porous structure provides high surface area for gas-sorbent interaction, enabling effective CO2 capture through adsorption equilibrium rather than energy-intensive chemical reactions or phase changes
Solution Approach 2:
The patent utilizes pressure swing adsorption (PSA) and temperature swing adsorption (TSA) to change operating parameters (pressure and temperature) for CO2 capture and desorption. By cycling between high-pressure/low-temperature conditions for adsorption and low-pressure/high-temperature conditions for desorption, the system achieves CO2 separation without continuous energy input required by conventional methods
2Use of energy by moving object
If physical adsorbents (zeolites, carbon molecular sieves, activated carbons) are used for CO2 capture, then the process is less energy intensive, but selectivity for CO2 relative to water vapor is insufficient
Solution Approach 1:
The patent creates composite carbon sorbent materials combining carbon base material with metal salts (such as copper, zinc, nickel, or manganese salts) to enhance CO2 selectivity. The metal-containing functional groups on the carbon surface provide specific interaction sites for CO2 molecules, improving selectivity over water vapor while maintaining the low energy consumption characteristics of physical adsorption
Solution Approach 2:
The patent modifies specific local regions of the carbon sorbent surface by introducing metal-containing functional groups at controlled concentrations. This local functionalization creates selective binding sites for CO2 without altering the overall porous structure and low-energy adsorption mechanism of the bulk material
3Quantity of substance
If chemical absorption using aqueous alkanolamine solutions is used, then CO2 can be captured, but capital expenses and operational costs increase significantly
Solution Approach 1:
The patent replaces complex chemical absorption systems (requiring heat exchangers, condensers, pumps for circulating large volumes of aqueous solutions) with simpler physical adsorption systems using solid porous sorbents. The adsorption process occurs directly on the sorbent surface, eliminating the need for extensive thermal processing equipment and solution circulation infrastructure
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 carbon sorbent exhibits enhanced CO2 capture capacity and selectivity, achieving higher CO2 adsorption relative to water vapor, with a bulk density greater than conventional sorbents, suitable for use in pressure swing adsorption systems.
Implementation Method 1
Other methods of CO2 capture include pressure swing adsorption (PSA) and vacuum swing adsorption (VSA). Such methods use physical adsorbents, such as zeolites, carbon molecular sieves, or activated carbons, for capturing the CO2.
Implementation Method 2
a carbon sorbent for removal of carbon dioxide from a gaseous material comprises a carbon content of at least about 90.0 atomic percent at a surface of the carbon sorbent and a nitrogen content of at least about 2.0 atomic percent at the surface of the carbon sorbent
Data Source
AI summary
A carbon sorbent for removing carbon dioxide from a gaseous material includes a surface composition including carbon, nitrogen, and oxygen. The nitrogen atoms at the surface of the carbon sorbent may be present in pyridone, pyrrole, and pyridine. The surface of the carbon sorbent may include lactone groups and pyrone groups. The carbon sorbent may have a bulk density greater than about 0.40 grams per cubic centimeter. The carbon sorbent may be formed using amino acids to provide the nitrogen for the carbon sorbent. In addition, the use of processing aids during the formation of the carbon sorbent facilitates the formation of a denser carbon sorbent. Related methods of forming the carbon sorbent and pellets of the carbon sorbent are also disclosed.