Multi-Stage Absorber for CO2 and H2S Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for removing CO2 and H2S from natural gas and coal seam gas face challenges such as high regeneration energy consumption and incomplete removal of H2S, leading to increased energy costs and residual H2S concentrations in treated gases.
Innovation Solution
A multi-stage absorption process using lean and semi-lean solutions in absorbers, followed by a flash drum and stripper, with optional adsorption using oxides of titanium and molybdenum, to reduce the circulation of rich solutions and regenerate the gas efficiently, while ensuring low H2S concentrations in the treated gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess amount of rich solution is circulated to decrease property change during CO2 absorption, then absorption performance is improved, but regeneration energy consumption is increased
Solution Approach 1:
The absorption process is divided into two separate absorbers: a first absorber for H2S removal using rich solution, and a second absorber for CO2 removal using semi-lean solution. This segmentation allows each absorber to be optimized for its specific function, preventing the property changes in rich solution from affecting overall absorption performance while reducing the total amount of rich solution that requires regeneration.
Solution Approach 2:
Instead of circulating excess rich solution through a single absorber, the invention uses partial action by having the first absorber remove H2S with rich solution, then the second absorber removes CO2 with the resulting semi-lean solution. This partial removal approach in stages achieves the required purification without the energy penalty of circulating excessive rich solution.
2Loss of energy
If pressure is lowered to regenerate rich solution by releasing absorbed CO2 and H2S, then regeneration is achieved, but predetermined performance cannot be obtained at absorption stage due to high remaining concentration
Solution Approach 1:
The invention segments the gas purification function into two absorbers with different solution types: the first absorber uses rich solution optimized for H2S removal, while the second absorber uses semi-lean solution optimized for CO2 removal. This segmentation ensures that each absorber operates at optimal performance for its target gas, preventing the compromise that occurs when a single absorber must handle both gases.
Solution Approach 2:
The invention changes the parameter of solution composition between absorbers. The first absorber operates with rich solution (high amine concentration) for H2S removal, while the second absorber operates with semi-lean solution (lower amine concentration) for CO2 removal. This parameter change optimizes each stage for its specific function, achieving both high H2S removal and low CO2 breakthrough.
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 reduces the energy required for regeneration and achieves a significant decrease in H2S concentrations in the treated gas, enhancing the efficiency and effectiveness of the gas purification process.
Implementation Method 1
H2S primarily dissolves in advance in rich solution in the regions from a down stage to a middle stage of an absorber and is removed
Implementation Method 2
a method is known in which the pressure of the rich solution that has absorbed CO2 and H2S is lowered and the rich solution is regenerated by releasing the absorbed CO2 and H2S
Implementation Method 3
A remaining part of the semi-lean solution in the flash drum is introduced into a stripper and heated to release remaining CO2 and H2S from the rich solution
Implementation Method 4
adsorption using oxides of titanium and molybdenum
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and a device for removing acidic materials, such as CO2 and H2S, with limited energy consumption are provided. The method comprises a step of introducing the feed gas (21) into a first absorber (1), and removing CO2 and H2S from the feed gas (21) by contacting the feed gas (21) with a lean solution (27) in the first absorber (1); and a step of introducing the feed gas (21) into a second absorber (2), and removing CO2 and H2S remaining in the feed gas (21) by contacting the feed gas (21) first with a semi-lean solution (28) and then with another part of the lean solution (27). The rich solution (25) having absorbed CO2 and H2S in the first and second absorber (1,2) is regenerated in a flash drum (4) and a stripper (5).