CO2 Purification by Liquid Expansion and Column Separation
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Solution Overview
Problem
Current carbon dioxide purification processes from oxyfuel combustion and hydrogen PSA processes face inefficiencies in achieving high carbon dioxide recovery and purity, particularly in removing oxygen and carbon monoxide contaminants, which hinders economic and energy-efficient carbon capture and storage.
Innovation Solution
A method involving compressing impure carbon dioxide, condensing it, expanding the liquid, and separating it in a mass transfer separation column system to produce high-purity carbon dioxide with minimal contaminant levels, allowing for direct transportation as a liquid or supercritical fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current purification processes are used to remove oxygen and carbon monoxide from carbon dioxide, then contaminant levels are reduced, but carbon dioxide recovery remains below 97% and energy consumption is high
Solution Approach 1:
The patent utilizes phase transitions of carbon dioxide between gas and liquid states, combined with pressure changes, to achieve separation of contaminants. By cycling through compression (gas to liquid), expansion (liquid to gas), and phase separation, the process achieves high purity carbon dioxide recovery above 97% while managing energy consumption through heat integration.
2Ease of operation
If carbon dioxide is compressed to pipeline pressure, then transportation is enabled, but power consumption increases and two phase flow conditions may arise
Solution Approach 1:
The process employs controlled phase transitions of carbon dioxide to achieve pipeline pressure (73-300 bar) while managing energy consumption. By utilizing the compression-expansion- phase separation cycle, the system enables liquid carbon dioxide transportation without excessive power consumption and avoids problematic two-phase flow conditions in pipelines.
3Manufacturing precision
If cooling is applied to condense carbon dioxide for separation, then purification is achieved, but energy consumption increases
Solution Approach 1:
The patent converts the exothermic heat of compression into a beneficial resource by using it for condensation and heating requirements within the process. The compression step, which generates heat, is integrated to provide the necessary thermal energy for phase changes and contaminant removal, thereby reducing external cooling energy consumption while achieving high purity carbon dioxide.
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 approach achieves carbon dioxide recovery rates above 97% with high purity, reducing energy consumption and enabling efficient transportation and storage, while minimizing oxygen and carbon monoxide levels below 100 ppm.
Implementation Method 1
compressing impure carbon dioxide gas to produce compressed impure carbon dioxide gas
Implementation Method 2
condensing it, expanding the liquid
Implementation Method 3
expanding at least a portion of said impure carbon dioxide liquid to produce expanded impure carbon dioxide liquid
Implementation Method 4
separating at least a portion of said expanded impure carbon dioxide liquid in a mass transfer separation column system to produce first contaminant-enriched overhead vapor and carbon dioxide bottoms liquid
Data Source
AI summary
Impure carbon dioxide (“CO2”) comprising a first contaminant selected from the group consisting of oxygen (“O2”) and carbon monoxide (“CO”) is purified by separating expanded impure carbon dioxide liquid in a mass transfer separation column system. The impure carbon dioxide may be derived from, for example, flue gas from an oxyfuel combustion process or waste gas from a hydrogen (“H2”) PSA system.