CO2 Absorber Solvent Stripping for Low CO Levels
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Solution Overview
Problem
Current acid gas removal processes face challenges in reducing carbon monoxide levels in carbon dioxide streams to below 1 mole % due to high CO levels in partially shifted or unshifted syngas feeds, leading to excessive electricity requirements and increased solvent and utility demands.
Innovation Solution
A process that involves contacting synthesis gas with a first liquid solvent to remove carbon dioxide, then transferring absorbed CO from the solvent to a shifted syngas stream, using a combination of solvents and flash drums to minimize CO in the product CO2 stream, optimizing the CO2 removal section configuration to reduce electricity consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional acid gas removal processes are used to remove CO2 from partially shifted or unshifted syngas, then CO2 removal is achieved, but CO levels in the product CO2 stream increase to unacceptable levels
Solution Approach 1:
The process divides CO removal into two distinct stages: first, CO is absorbed along with CO2 in the primary absorber; second, CO is selectively stripped from the rich solvent in a dedicated stripper unit. This segmentation allows independent optimization of each function, achieving both high CO2 removal and low CO levels in the product stream.
Solution Approach 2:
A dedicated stripper unit acts as an intermediary between the absorber and product CO2 stream. This intermediate device transfers CO from the rich solvent to a separate gas stream, preventing CO from contaminating the product CO2 while maintaining efficient CO2 removal in the absorber.
2Manufacturing precision
If CO levels in product CO2 are reduced to below 1 mole %, then product quality improves, but electricity requirements and solvent demands increase excessively
Solution Approach 1:
The stripper unit serves as an intermediary that handles CO removal separately, allowing the main absorber to focus on CO2 removal without excessive energy input. This division prevents the need for high-energy operations in the primary CO2 removal step.
Solution Approach 2:
The process utilizes temperature and pressure changes in the stripper unit to selectively desorb CO from the rich solvent. By controlling these parameters, CO is transferred to a separate stream while minimizing solvent losses and energy consumption in the overall process.
3Quantity of substance
If CO is absorbed from partially shifted syngas in the primary absorber, then CO2 removal efficiency increases, but CO contaminates the product CO2 stream
Solution Approach 1:
The stripper unit extracts CO from the rich solvent that was absorbed in the primary absorber. This extraction step removes the harmful CO component before the solvent is regenerated, ensuring CO does not contaminate the product CO2 stream while maintaining high CO2 absorption capacity in the absorber.
Solution Approach 2:
The stripper acts as an intermediary processing step that separates CO from the solvent stream. This intermediate treatment allows the system to benefit from high CO2 absorption in the primary unit while eliminating CO contamination through the stripping operation.
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 effectively reduces CO levels in the product CO2 stream to manageable levels, decreasing electricity requirements and associated costs by desorbing CO from the solvent and preventing its entry into the product CO2, while maintaining the properties of the treated fully shifted syngas.
Implementation Method 1
contacting the synthesis gas with a first liquid solvent in a first acidic gas removal unit to selectively absorb and remove at least a portion of carbon dioxide from the synthesis gas
Implementation Method 2
contacted with the first liquid solvent mixed with a second liquid solvent to remove CO2 from a shifted synthesis gas to produce a purified shifted synthesis gas
Implementation Method 3
at least a portion of CO from said first liquid solvent is transferred to said purified shifted synthesis gas
Implementation Method 4
at least a portion of CO from said first liquid solvent is transferred to said purified shifted synthesis gas
Data Source
AI summary
A process for maintaining a low carbon monoxide content in a carbon dioxide product that is made in a synthesis gas purification process is disclosed. More particularly, the invention involves an improved process in which a portion of a loaded solvent is sent through a carbon dioxide absorber instead of to a series of carbon dioxide flash drums.