CO2 Separation Column Reboiling for High-Purity Carbon Dioxide
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Solution Overview
Problem
Current carbon dioxide purification processes from oxyfuel combustion and hydrogen PSA processes face challenges in achieving high carbon dioxide recovery and purity, particularly in reducing oxygen and carbon monoxide levels, while being energy-efficient and cost-effective.
Innovation Solution
A method involving a mass transfer separation column system that separates impure liquid carbon dioxide to produce contaminant-enriched overhead vapor and carbon dioxide-enriched bottoms liquid, with reboiling and indirect heat exchange to enhance carbon dioxide recovery and purity, and a reboiler to produce carbon dioxide-enriched vapor, using internal refrigeration from expanded carbon dioxide-enriched liquids to reduce energy consumption.
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 increases
Solution Approach 1:
The patent employs phase transitions of carbon dioxide between liquid and vapor states within the mass transfer separation column system. By controlling temperature and pressure conditions, the process achieves high-purity carbon dioxide separation through condensation and vaporization cycles, enabling both high purity (≥99 mol%) and high recovery (>97%) simultaneously
Solution Approach 2:
The process uses internally generated cold streams from the carbon dioxide purification process itself to provide refrigeration for the separation column. The expanded carbon dioxide-enriched liquids from the reboiler serve as the cooling medium, eliminating the need for external refrigerants and reducing energy consumption while maintaining high recovery rates
2Manufacturing precision
If external refrigerants are used for cooling in the purification process, then separation efficiency is improved, but energy consumption and operational complexity increase
Solution Approach 1:
The process utilizes its own internal cold streams for refrigeration. The expanded carbon dioxide-enriched liquids generated during the separation process are used to cool incoming feed streams and provide refrigeration duty for the mass transfer separation column, making the system self-sufficient and eliminating external refrigerant requirements
Solution Approach 2:
The cooling function is merged with the separation process itself. The mass transfer separation column system integrates the refrigeration cycle with the purification operation, where the same equipment that separates carbon dioxide also generates the cold streams needed for cooling, reducing overall energy consumption and equipment complexity
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 method achieves carbon dioxide recovery of over 97% with a purity of at least 99 mol%, significantly reducing oxygen and carbon monoxide levels, while maintaining minimal power consumption and avoiding external refrigerants.
Implementation Method 1
separating impure liquid carbon dioxide in a mass transfer separation column system to produce first contaminant-enriched overhead vapor and carbon dioxide-enriched bottoms liquid
Implementation Method 2
reboiling a portion of said carbon dioxide-enriched bottoms liquid by indirect heat exchange against crude carbon dioxide fluid to produce carbon dioxide-enriched vapor
Implementation Method 3
using internal refrigeration from expanded carbon dioxide-enriched liquids to reduce energy consumption
Data Source
AI summary
A first contaminant selected from oxygen and carbon monoxide is removed from impure liquid carbon dioxide using a mass transfer separation column system which is reboiled by indirect heat exchange against crude carbon dioxide fluid, the impure liquid carbon dioxide having a greater concentration of carbon dioxide than the crude carbon dioxide fluid. The invention has particular application in the recovery of carbon dioxide from flue gas generated in an oxyfuel combustion process or waste gas from a hydrogen PSA process. Advantages include reducing the level of the first contaminant to not more than 1000 ppm.