Selective H2S Removal via Basic Nitrogenous Sorbent
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Solution Overview
Problem
Current natural gas treatment processes are inefficient in selectively removing hydrogen sulfide (H2S) from gas streams containing CO2, leading to increased processing costs and resource loss, as they often remove CO2 more than necessary, and lack advanced technologies for large-scale rapid separation.
Innovation Solution
A cyclic process utilizing a non-aqueous sorbent comprising a basic non-protogenic nitrogenous compound that selectively reacts with H2S, allowing for its sorption and subsequent desorption, particularly using pressure swing and temperature swing adsorption variants with solid or liquid phase sorbents to achieve high H2S selectivity over CO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PSA or TSA processes are used to remove acid gases, then H2S removal is achieved, but CO2 is also removed excessively leading to increased processing costs and reduced methane recovery
Solution Approach 1:
The patent applies local quality by functionalizing specific regions of the sorbent material with basic nitrogenous compounds that have selective affinity for H2S. The sorbent contains both selective H2S-binding sites and non-selective regions, creating localized functionality that preferentially captures H2S while allowing CO2 and methane to pass through, thus achieving selective removal without excessive CO2 removal or methane loss.
Solution Approach 2:
The patent utilizes parameter changes by modifying the chemical properties of the sorbent material through functionalization with basic nitrogenous compounds. This changes the sorbent's selectivity parameters, enabling it to distinguish between H2S and CO2 based on their different chemical reactivities with the basic functional groups, thereby achieving selective H2S removal while minimizing CO2 removal and methane loss.
2Reliability
If unselective removal processes are used between H2S and CO2, then both gases are removed, but treatment becomes unnecessarily severe increasing processing costs
Solution Approach 1:
The patent changes the selectivity parameter of the sorbent material by introducing basic nitrogenous functional groups that have differential affinity for H2S versus CO2. This parameter modification enables the sorbent to selectively bind H2S at lower concentrations and more favorable equilibrium conditions, reducing the severity of treatment required and lowering processing costs while maintaining effective gas purification.
Solution Approach 2:
The patent employs composite materials by combining a base sorbent material with basic nitrogenous functional groups. This composite structure integrates the physical adsorption capabilities of the base material with the selective chemical binding properties of the basic functional groups, creating a material that achieves selective H2S removal at lower costs compared to unselective removal processes.
3Productivity
If conventional sorbents are used, then general acid gas removal is achieved, but selective H2S removal with high efficiency is not attained
Solution Approach 1:
The patent applies local quality by creating specific functionalized regions within the sorbent material that have high selective affinity for H2S. These localized basic nitrogenous sites provide preferential binding for H2S molecules while being less interactive with CO2 and methane, thereby achieving both high separation efficiency for H2S and high selectivity without excessively removing CO2 or methane.
Solution Approach 2:
The patent changes the chemical parameter of the sorbent by introducing basic nitrogenous functional groups that modify the binding characteristics. This parameter change increases both the productivity (separation efficiency) and reliability (selectivity) by creating stronger and more selective interactions with H2S compared to conventional non-functionalized sorbents, enabling efficient selective removal.
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 process effectively separates H2S from CO2, reducing H2S content in natural gas streams while minimizing methane loss, enabling more efficient gas processing and reducing operational costs by preferentially desorbing CO2 followed by H2S, suitable for large-scale industrial applications.
Implementation Method 1
contacting the gas mixture under sorption conditions with a non-aqueous sorbent comprising a basic non-protogenic nitrogenous compound to react the H2S with the basic compound so that the H2S is sorbed by the compound
Implementation Method 2
The well-established pressure swing adsorption (PSA) process has been used in this way since about the 1960s. In the PSA process, the solid sorbent is contained in a vessel and adsorbs the contaminant gas species
Implementation Method 3
subjecting the sorbent to desorption conditions by which the H2S is desorbed
Implementation Method 4
The well-established pressure swing adsorption (PSA) process has been used in this way since about the 1960s
Implementation Method 5
Temperature swing adsorption (TSA) provides an alternative to the pressure swing technology in which the sorbed component is desorbed by an increase in temperature
Data Source
AI summary
A cyclic process for selectively separating hydrogen sulfide from a gas mixture including CO2 is operated by contacting the gas mixture under sorption conditions with a non-aqueous sorbent comprising a basic non-protogenic nitrogenous compound to react the H2S with the basic compound so that the H2S can be sorbed by the compound. The compound containing the sorbed H2S can then be subjected to desorption conditions by which the H2S is desorbed and the sorbent readied for another sorption step in the cycle. The basic nitrogenous compound can be carried on a porous solid sorbent, e.g., a solid oxide such as alumina, silica, silica-alumina, zeolites, or a mesoporous and/or macroporous solid oxide. The process may be operated using a pressure swing, temperature swing, partial pressure swing, purge displacement, or a combination thereof between the sorption and desorption portions of the cycle, preferably in a rapid cycle operation.