Hydrogen-CO2 Gas Mixture Production via Adsorption and Cycle Gas
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Solution Overview
Problem
Existing CO2 separation technologies are inefficient for low CO2 content gas mixtures, requiring high CO2 partial pressure and energy-intensive desorption processes, and lack a simple and cost-effective method to adjust CO2 content in hydrogen-CO2 gas mixtures for further processing.
Innovation Solution
A process involving CO2 isolation using adsorbers, desorption with heated hydrogen gas, and adjustment of CO2 volume fraction using a cycle gas system to produce a hydrogen-CO2 gas mixture suitable for methanol synthesis, utilizing a cycle gas system to enhance CO2 content independently of partial pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amine scrubbing is used to isolate CO2, then CO2 separation is effective, but the process requires relatively high CO2 partial pressure and is not suitable for low CO2 content gas mixtures
Solution Approach 1:
The patent changes the separation mechanism from chemical absorption (amine scrubbing) to physical adsorption using solid adsorbers. This parameter change allows the process to effectively separate CO2 from gas mixtures with low CO2 content (0.01% to 20% volume fraction), including direct air capture applications, without requiring high CO2 partial pressure.
2Quantity of substance
If temperature swing process is used to desorb CO2 from adsorber, then CO2 desorption is achieved, but energy-intensive drying with superheated steam is required
Solution Approach 1:
The patent introduces hydrogen as an intermediary substance that serves dual functions: (1) as a desorbing agent that displaces CO2 from the adsorber through competitive adsorption, and (2) as a heating medium that provides the necessary temperature elevation for desorption. This eliminates the need for energy-intensive superheated steam drying, as the CO2-hydrogen mixture can be directly used for downstream applications like methanol synthesis.
3Ease of operation
If isothermal backwashing with hydrogen is used, then the process is simple, but desorption is incomplete since desorption is an endothermic process
Solution Approach 1:
The patent modifies the isothermal backwashing process by introducing temperature elevation during the hydrogen backwashing step. Since desorption is an endothermic process, heating the adsorber during hydrogen backwashing provides the necessary energy to complete CO2 desorption, thereby improving desorption completeness while maintaining process simplicity.
4Adaptability or versatility
If low-CO2 gas mixture is processed, then the adsorber can handle diverse feedstocks, but there is no way to increase the CO2 partial pressure of the gas mixture
Solution Approach 1:
The patent extracts CO2 from low-CO2 gas mixtures using the adsorber, concentrating the CO2 in the desorbed gas stream. By using hydrogen backwashing with temperature elevation, the process effectively extracts and concentrates CO2 regardless of the initial CO2 content in the feed gas, thereby enabling downstream processes to receive gas mixtures with sufficient CO2 partial pressure.
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
Enables efficient production of a hydrogen-CO2 gas mixture with adjustable CO2 content for methanol synthesis, reducing energy consumption and costs by using hydrogen as a desorber gas and heat-transfer medium.
Implementation Method 1
This problem can be solved by adsorption of CO2 on solid adsorbers
Implementation Method 2
II) desorption of the CO2 using a heated hydrogen-containing gas stream in a desorber
Implementation Method 3
desorption of the CO2 using a heated hydrogen-containing gas stream
Implementation Method 4
III) adjustment of the CO2 volume fraction of the hydrogen-containing gas stream to the target content using a cycle gas system, by means of which the heated hydrogen-CO2 gas mixture is passed through the desorber
Data Source
AI summary
A process for producing a hydrogen-carbon dioxide gas includes isolating CO2 from gas mixtures having a volume fraction of CO2 in the range from 0.01% to 20% using an adsorber and desorption of the CO2 using a heated hydrogen-containing gas stream in a desorber. The process also includes adjusting the CO2 volume fraction of the hydrogen-containing gas stream to the target content using a cycle gas system. The heated hydrogen-CO2 gas mixture is completely or partially passed through one or more desorbers thereby increasing the CO2 volume fraction in the hydrogen-CO2 gas mixture until achievement of a target value.