Flash Column Contaminant Removal in CO2 Purification
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Solution Overview
Problem
Conventional methods for recovering high purity carbon dioxide from gaseous sources face challenges such as contamination from nitrogen oxides, sulphurous compounds, and volatile organic compounds like benzene, which require costly and hazardous chemicals, and are inefficient in varying gas compositions.
Innovation Solution
Incorporating a flash column between the absorption and stripper columns, where a warm wet carbon dioxide stream is introduced, effectively removes contaminants like NOx, sulphurous compounds, and benzene, reducing the need for subsequent oxidation steps and chemical consumption, and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional absorption method with amine-based agent is used to recover carbon dioxide, then carbon dioxide can be absorbed from gaseous source, but contaminants such as nitrogen oxides, sulphurous compounds and volatile organic compounds are also absorbed together with carbon dioxide
Solution Approach 1:
The invention divides the purification process into multiple stages: first absorption stage for CO2 capture, followed by flash vaporization to remove absorbed contaminants, then stripping stage for final CO2 recovery. This segmentation allows selective removal of contaminants at different process points rather than attempting to separate them all at once.
Solution Approach 2:
The flash vaporization step is introduced before the final stripping process to preliminarily remove contaminants that were absorbed during CO2 capture. By performing this preliminary removal action, the subsequent stripping stage operates on a cleaner stream, reducing the burden on downstream equipment and improving overall purification efficiency.
2Object-generated harmful factors
If oxidation process is used to remove nitrogen oxides and sulphur compounds from stripper off gas, then these contaminants can be oxidized to nitrate and free sulphur, but large supply of hazardous chemicals such as potassium permanganate is required
Solution Approach 1:
The invention converts the harmful effect of absorbed contaminants into a beneficial separation mechanism. By utilizing flash vaporization, the contaminants that were harmful when absorbed are actually removed in the vapor phase, leaving cleaner liquid for subsequent CO2 recovery. This transforms the contamination problem into a selective vapor-liquid separation opportunity.
Solution Approach 2:
The flash vaporization step acts as an intermediary process between absorption and stripping. It serves as a mediating stage that removes contaminants without requiring hazardous chemicals, using only thermal energy to achieve vaporization and separation. This intermediary step eliminates the need for chemical oxidants while still achieving contaminant removal.
3Object-generated harmful factors
If carbon filter is used to remove benzene from gaseous stream, then benzene can be removed, but the carbon filter may not retain all benzene when gas composition varies
Solution Approach 1:
The invention changes the operational parameters by using flash vaporization temperature and pressure control to enhance benzene removal. By adjusting these parameters, the system adapts to varying gas compositions and maintains effective contaminant removal without relying solely on carbon filter capacity, which has fixed characteristics.
4Manufacturing precision
If multiple purification steps including oxidation, adsorption and distillation are used to achieve high purity carbon dioxide, then required purity can be obtained, but device complexity and cost increase
Solution Approach 1:
The invention merges the absorption and contaminant removal functions into a unified flash vaporization-stripping process. Instead of separate equipment for each purification function, the system combines CO2 recovery with contaminant removal in an integrated process flow, reducing overall device complexity while maintaining high purity output.
Solution Approach 2:
The flash vaporization and stripping equipment performs multiple functions simultaneously: it removes absorbed contaminants (nitrogen oxides, sulphurous compounds, volatile organics), recovers carbon dioxide, and prepares the stream for final purification. This multi-functionality reduces the need for dedicated equipment for each task, simplifying the overall system.
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 significantly reduces contaminant levels in the stripper off-gas, eliminates the need for hazardous chemicals, increases product yield, and maintains purity regardless of gas composition changes, while lowering energy consumption and extending equipment lifespan.
Implementation Method 1
separating by means of flashing the liquid obtained in step c into a contaminant-rich gas and a contaminant-depleted liquid
Implementation Method 2
separating by means of flashing the liquid obtained in step c into a contaminant-rich gas and a contaminant-depleted liquid
Implementation Method 3
absorbing the gas in an absorbing agent, by which the gas is separated into a carbon dioxide-lean gas and a carbon dioxide-rich liquid
Implementation Method 4
separating the liquid obtained in step e into a carbon dioxide-rich stripper off gas and a carbon dioxide-depleted liquid by means of stripping
Data Source
AI summary
The present invention relates to a method for recovery of high purity carbon dioxide from a gaseous source and uses thereof. More specifically, the present invention relates to the production of high purity carbon dioxide, which is substantially free of nitrogen, oxygen, nitrogen oxides, sulphurous compounds and volatile organic contaminants, particularly benzene. The present invention also relates to a method for removal of benzene from a carbon dioxide feeding gas as well as the use of said high purity carbon dioxide in foodstuffs.