Aminopyridine Derivatives for Selective H2S Removal
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Solution Overview
Problem
Existing methods for removing hydrogen sulfide (H2S) from fluid streams, particularly those containing carbon dioxide, are inefficient due to reduced effectiveness at high CO2 concentrations, require specialized equipment, and have limitations in solubility and safety concerns with existing amine solutions.
Innovation Solution
The use of 1-hydroxyethyl-4-pyridinlypiperazine compounds in an aqueous absorbent solution, optionally combined with other amino compounds, to selectively remove H2S from fluid streams, improving solubility and effectiveness across a broad range of CO2 concentrations without needing high shear conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional amine solutions (MEA, DEA) are used to remove H2S from gas streams, then H2S removal capability is improved, but safety concerns arise due to irritant properties and flammability of the amine and ethylene oxide
Solution Approach 1:
The patent changes the chemical parameters of the absorbent by using aminopyridine derivatives with specific molecular structures (formula I) that have different safety profiles while maintaining H2S removal capability. The compounds are designed to be less hazardous than conventional amines while preserving the desired functional performance.
Solution Approach 2:
The patent employs composite absorbent solutions combining aminopyridine derivatives with co-absorbents or additives to enhance both H2S removal efficiency and safety characteristics. The composite formulation allows optimization of both performance and safety attributes simultaneously.
2Reliability
If MDEA is used for selective H2S removal from CO2-H2S mixtures, then H2S selectivity is improved, but effectiveness is reduced at high CO2 concentrations due to accelerated CO2 absorption
Solution Approach 1:
The patent modifies the chemical parameters of the absorbent by introducing aminopyridine derivatives with specific structural features (formula I) that change the absorption characteristics. These compounds exhibit different CO2 and H2S absorption rates compared to MDEA, enabling effective H2S removal even at high CO2 concentrations without the acceleration problem.
Solution Approach 2:
The patent creates a new class of absorbent compounds that replicate the selective H2S removal function of MDEA while avoiding its limitation at high CO2 concentrations. The aminopyridine derivatives serve as functional copies that improve upon the performance constraints of existing technologies.
3Reliability
If severely hindered amino compounds are used for H2S removal, then selectivity is improved, but the method cannot provide for low levels of H2S (lower than 10 ppm)
Solution Approach 1:
The patent changes the sensitivity parameters of the absorption system by using aminopyridine derivatives with optimized molecular structures. These compounds provide both high selectivity and high sensitivity, enabling detection and removal of H2S at concentrations below 10 ppm while maintaining excellent selectivity characteristics.
4Reliability
If 4-dimethylaminopyridine is used for H2S removal, then some H2S removal capability is achieved, but limited solubility in water requires specialized solvents
Solution Approach 1:
The patent modifies the solubility parameters of the absorbent by introducing aminopyridine derivatives with specific substituent patterns (formula I). These structural modifications enhance water solubility while preserving H2S removal capability, eliminating the need for specialized non-aqueous solvents and simplifying the manufacturing and operation process.
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 with high selectivity over CO2, demonstrating improved solubility and performance compared to existing methods, while minimizing CO2 absorption and ensuring safety by avoiding hazardous materials.
Implementation Method 1
contacting the fluid stream with an aqueous absorbent solution comprising the 1-hydroxyethyl-4-pyridinlypiperazine compound... effectively removes H2S with high selectivity over CO2
Data Source
AI summary
The present invention relates to a novel class of aminopyridine derivatives with the general formula: wherein R1; R2, R3, and R4 are each independently hydrogen, an alkyl group, —(O—CH2—CH2)n-OH wherein n is an integer from 0 to 8, —CH2—(O—CH2—CH2)n-OH wherein n is an integer from 0 to 8, an hydroxyalkyl group, an aminoalkyl group where the nitrogen can be part of a 5 or 6 ring membered cycle, an alkylene group containing quaternary ammonium, a carboxylic acid and/or a salt thereof, or a sulphonic acid and/or a salt thereof, preferably R1; R2, R3, and R4 are each hydrogen. The compounds are useful for removal of hydrogen sulfide and other impurities from fluid streams containing hydrogen sulfide, including selective removal from such streams which also contain carbon dioxide. Examples of the fluid stream include a gas stream, for example natural gas, synthesis gas, tail gas, refinery gas, or from liquid streams such as liquid or liquefied hydrocarbons, for example Liquefied Petroleum Gas or Natural Gas Liquids.