Aqueous Alkanolamine Absorbent for H2S Removal at Elevated Temperatures
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Solution Overview
Problem
Existing aqueous amine solutions for removing acid gases, such as H2S, from gaseous mixtures are less effective at elevated temperatures, limiting their commercial viability.
Innovation Solution
An aqueous alkanolamine solution comprising 3-(dimethylamino)-1,2-propanediol or 3-(diethylamino)-1,2-propanediol, piperazine, and additional amino compounds, used at elevated temperatures, effectively removes acid gases including H2S by contact with gaseous mixtures, with optional physical solvents and without acids or acid-forming materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous amine solutions are used for removing acid gases, then acid gas removal is achieved, but the removal capacity decreases at elevated temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous solution by incorporating specific alkanolamines (3-dimethylamino-1,2-propanediol or 3-diethylamino-1,2-propanediol) in combination with piperazine and other amino compounds. This compositional parameter change enables the solution to maintain high acid gas removal capacity at elevated temperatures above 140°F, resolving the temperature-dependent capacity loss of conventional amine solutions
Solution Approach 2:
The patent creates a composite aqueous solution system combining multiple amino compounds with complementary properties. The specific formulation containing 20-50 wt% alkanolamine, 2-10 wt% piperazine, and additional amino compounds produces synergistic effects that enhance thermal stability and maintain removal capacity at elevated operating temperatures
2Productivity
If aqueous amine solutions are used at elevated temperatures for commercial viability, then productivity increases, but acid gas removal effectiveness deteriorates
Solution Approach 1:
By modifying the chemical composition to include thermally stable alkanolamine structures with specific molecular configurations, the solution maintains high removal effectiveness while enabling operation at elevated temperatures that improve commercial viability through enhanced kinetics and reduced viscosity
Solution Approach 2:
The patent introduces amino compounds with specific local molecular structures (branched alkyl groups, hydroxyl positions) that provide localized thermal stability while maintaining bulk solution reactivity. This local structural optimization allows the solution to withstand elevated temperatures without losing removal effectiveness
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
The solution maintains high acid gas removal capacity at temperatures above 140°F (60°C), achieving efficient H2S removal from gaseous mixtures, meeting commercial viability standards and environmental regulations.
Implementation Method 1
aqueous amine solution contacts the gaseous mixture comprising the acidic gases counter currently at low temperature or high pressure in an absorber tower
Data Source
Figure 1~2
AI summary
The present invention relates to an aqueous alkanolamine solution for the removal of hydrogen sulfide from gaseous mixtures containing hydrogen sulfide. The aqueous alkanolamine solution comprises (i) an amino compound with the formula: R1R2NCH2CH(OH)CH2OH wherein R1and R2 independently represent lower alkyl groups of 1 to 3 carbon atoms, (ii) piperazine, and (iii) optionally a physical solvent, wherein said solution does not contain a strong acid. Further, the present invention relates to a process for removing hydrogen sulfide from a gaseous mixture containing hydrogen sulfide, and additionally other acid gases, if present, for example carbon dioxide, comprising the step of contacting the gaseous mixture contain hydrogen sulfide with the aqueous alkanolamine solution, preferably wherein the temperature of the aqueous alkanolamine solution is equal to or greater than 140?F. Examples of the gaseous mixtures include natural gas, synthesis gas, tail gas, and refinery gas.