Aqueous Alkanolamine Solution for H2S Removal at Elevated Temperatures
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Solution Overview
Problem
Existing methods for removing hydrogen sulfide (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, an acid with a pKa of 6 or less, and optional additional amino compounds, used at temperatures equal to or greater than 140°F (60°C), along with steam stripping to enhance H2S removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous amine solutions are used for H2S removal, then effective acid gas removal is achieved at low temperature, but the capacity decreases significantly at elevated temperatures
Solution Approach 1:
The patent modifies the chemical composition parameters of the aqueous solution by combining specific alkanolamines (such as MDEA, DEA, or DIPA) with accelerators (such as piperazine or hydroxylamine) in optimized ratios. This compositional parameter change enables the solution to maintain high H2S removal capacity at elevated temperatures up to 200°F, resolving the temperature-dependent capacity loss of conventional solutions
Solution Approach 2:
The invention creates a composite absorbent system by combining multiple amine components with complementary properties. The alkanolamine provides bulk capacity while the accelerator enhances reaction kinetics and temperature stability. This composite approach synergistically improves both low-temperature effectiveness and high-temperature reliability, extending the viable operating temperature range
2Productivity
If the operating temperature is increased to improve commercial viability, then processing efficiency increases, but the H2S removal capacity of existing solutions decreases
Solution Approach 1:
By changing the chemical composition parameters—specifically the ratio and types of amine components—the solution maintains optimal reaction kinetics across a broader temperature range. The accelerator component compensates for the natural decline in amine reactivity at higher temperatures, allowing the system to achieve both improved processing efficiency and sustained removal capacity
Solution Approach 2:
The composite solution dynamically adapts to temperature changes through the synergistic interaction of its components. As temperature increases, the system maintains effectiveness through the combined action of the alkanolamine and accelerator, which together provide temperature-resilient H2S removal performance rather than a static response
3Reliability
If select alkaline materials are mixed with acid to enhance acid gas removal, then removal capacity increases, but the selection is limited to a specific class of materials
Solution Approach 1:
The patent identifies a universal combination pattern that works across multiple alkanolamine types (MDEA, DEA, DIPA) with various accelerators (piperazine, hydroxylamine). This universal formulation approach eliminates the need for highly selective material choices and allows flexible adaptation to different application requirements while maintaining enhanced removal capacity
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 effectively removes H2S from gaseous mixtures at elevated temperatures, achieving commercially viable capacity and meeting environmental standards for hydrogen sulfide levels in treated gases.
Implementation Method 1
contacting the gaseous mixture with an aqueous solution of an amino compound and an acid to remove hydrogen sulfide from the gaseous mixture
Implementation Method 2
steam stripping to enhance H2S removal
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. 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 and (ii) an acid or acid-forming material having a pKa equal to or less than 8, optionally (iii) another amino compound, and optionally (iv) a physical solvent. Further, the present invention relates to a process for removing acid gases from a gaseous mixture, preferably hydrogen sulfide, comprising the step of contacting the gaseous mixture 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.