Hybrid Gas Absorption Process for Energy Recovery
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Solution Overview
Problem
Existing gas removal processes require significant external heat for regeneration, particularly in chemical absorption processes, which increases energy consumption and dependency on steam supply.
Innovation Solution
A hybrid process combining physical and chemical absorption-regeneration cycles, where physical absorption occurs at high partial pressures to reduce energy needs, and chemical absorption completes the process at lower pressures, utilizing steam efficiently to minimize external heat requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical absorption is used to remove gases from gas mixtures, then gas removal efficiency is improved, but external heat supply requirements increase significantly
Solution Approach 1:
The invention divides the gas removal process into two separate absorption columns: the first column performs bulk gas removal (e.g., CO2) with a chemical absorption solution, while the second column removes remaining traces of gas. This segmentation allows the energy-intensive chemical absorption to be applied only where needed, reducing overall heat requirements compared to using chemical absorption throughout the entire process.
Solution Approach 2:
The first absorption column is designed to remove the majority (e.g., 95%) of the target gas through chemical absorption, while the second column handles the remaining small fraction. This partial action approach means that the high energy consumption of chemical absorption is applied only to the bulk removal stage, not to the entire gas purification process, thereby reducing total external heat supply needs.
2Manufacturing precision
If two different chemical absorption solutions are used in series, then gas purity is improved, but regeneration heat supply remains unchanged
Solution Approach 1:
The invention merges physical absorption and chemical absorption into a hybrid process. The first column uses chemical absorption for bulk removal, while the second column uses physical absorption (with a different solvent) for trace removal. This combination achieves high gas purity through the complementary actions of both absorption mechanisms, while the physical absorption in the second column requires minimal or no external heat for regeneration, thus improving purity without proportionally increasing heat supply.
3Use of energy by moving object
If physical absorption is used for gas removal, then regeneration energy is reduced, but gas removal efficiency at low partial pressures decreases
Solution Approach 1:
The invention applies different absorption qualities to different stages of the process: chemical absorption (with high selectivity and capacity) is used in the first column where gas partial pressures are high, while physical absorption (with lower energy regeneration requirements) is used in the second column where gas partial pressures are low. This local optimization of absorption type matches the process conditions at each stage, achieving both efficient gas removal and reduced regeneration energy.
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 hybrid process significantly reduces the need for external heat in gas removal, reuses steam and desorbed gases to enhance flash regeneration, and achieves high purity gas treatment with reduced energy integration.
Implementation Method 1
physical absorption processes only when the partial pressures of the gases to be removed are higher and therefore at an early stage of the absorption process in which the solubility of the gases to be removed, which is governed by Henry's law
Implementation Method 2
the solubility of the gases to be removed, which is governed by Henry's law
Implementation Method 3
chemical absorption column (26) where it is contacted in countercurrent by a chemical absorption solution fed through conduit 40 and in which the total removal of gases to be removed takes place
Implementation Method 4
the regeneration of the solution to release the absorbed gases takes place primarily by flash following the reduction of the pressure of the solution
Implementation Method 5
can be improved and/or completed by stripping with steam, air or inert gas such as nitrogen
Data Source
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AI summary
A hybrid process for the selective absorption of gases from gas mixtures containing them, characterized by comprising the steps of: - an initial absorption of the gases to be removed by a physical absorption process by which up to 30% of the gases to be removed is absorbed by physical solubility in an absorbent solution which is subsequently flash- regenerated, and - a final absorption of the remaining gases with a chemical absorption process by which the remaining gases to be removed are chemically absorbed by an absorbent solution which is subsequently regenerated by means of a heat and/or steam external supply, the heat supplied for the regeneration of the chemical absorption solution and largely contained in the gas mixture exiting from the regeneration step being recovered and re-used in double effect for improving and/or for completing the flash-regeneration of the solution used for the physical absorption of the gases to be removed.