Claus Tail Gas Adsorption for High Sulfur Recovery
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Solution Overview
Problem
Conventional sulfur recovery methods, such as the Claus process, leave residual hydrogen sulfide in tail gases, which are not effectively recovered, leading to inefficiencies in sulfur recovery and potential environmental impacts.
Innovation Solution
A method involving a hydrogenation reactor, quench tower, and multiple stage adsorption units with specific adsorbents and regeneration processes to convert sulfur-containing compounds in Claus tail gas streams, achieving high sulfur recovery by converting hydrogen sulfide and separating it from carbon dioxide and nitrogen, using cryogenic separation and thermal oxidizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Claus process is used for sulfur recovery, then sulfur can be recovered from hydrogen sulfide, but residual hydrogen sulfide remains in the tail gas (less than 5% recovery efficiency)
Solution Approach 1:
The patent introduces an amine solution as an intermediary substance to absorb residual hydrogen sulfide from Claus tail gas. The amine solution acts as a mediator between the tail gas and the subsequent treatment stages, enabling effective removal of hydrogen sulfide that the Claus process alone cannot recover. This intermediary absorption step bridges the gap between conventional Claus recovery and complete sulfur recovery.
Solution Approach 2:
The patent changes the chemical parameters of the tail gas treatment by introducing chemical absorption using amine solutions, followed by thermal decomposition at elevated temperatures. This parameter change from physical condensation to chemical absorption and thermal breakdown enables recovery of residual hydrogen sulfide at concentrations below 5%, dramatically improving overall sulfur recovery rate.
2Productivity
If conventional Claus tail gas treatment is used, then processing is simpler, but sulfur recovery rate remains below 95%
Solution Approach 1:
The patent segments the tail gas treatment into distinct functional stages: amine absorption stage, thermal decomposition stage, and sulfur condensation stage. Each segment performs a specific function - the amine solution absorbs hydrogen sulfide, thermal decomposition breaks down the amine-H2S complex, and condensation recovers elemental sulfur. This segmentation enables high sulfur recovery while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent implements continuous circulation of the amine solution through absorption and regeneration cycles, ensuring uninterrupted hydrogen sulfide removal. The thermal decomposition continuously regenerates the amine solution, maintaining its absorption capacity. This continuous action ensures sustained high sulfur recovery rates without interruption, justifying the additional processing complexity.
3Productivity
If multiple adsorption stages are added to increase sulfur recovery, then hydrogen sulfide removal improves, but system complexity and operational difficulty increase
Solution Approach 1:
The amine solution system operates on self-service principles where the absorption medium automatically regenerates through thermal decomposition. The spent amine solution is heated to release hydrogen sulfide, and the regenerated amine returns to the absorption stage without requiring manual intervention. This self-regenerating system simplifies operation despite multiple treatment stages, as the system maintains itself through inherent chemical cycles.
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 enables sulfur recovery rates greater than 99%, effectively recycling hydrogen sulfide and minimizing environmental impact by efficiently processing residual sulfur-containing compounds in Claus tail gas streams.
Implementation Method 1
converting sulfur-containing compounds in a Claus tail gas stream to hydrogen sulfide
Implementation Method 2
condensing liquid water into a water condensate stream
Implementation Method 3
adsorbing water from the quenched gas stream
Implementation Method 4
adsorbing hydrogen sulfide from the first outlet gas stream
Implementation Method 5
feeding the carbon dioxide stream to a thermal oxidizer
Data Source
AI summary
A method for sulfur recovery includes, in a hydrogenation reactor, converting sulfur-containing compounds in a Claus tail gas stream to hydrogen sulfide to produce a hydrogenated gas stream; feeding the hydrogenated gas stream to a quench tower to produce a quenched gas stream by condensing liquid water; feeding the quenched gas stream to a first stage adsorption vessel of a first stage adsorption unit to produce a first outlet gas stream by adsorbing water from the quenched gas stream; feeding the first outlet gas stream to a second stage adsorption vessel of a second stage adsorption unit to produce a second byproduct gas stream by adsorbing hydrogen sulfide from the first outlet gas stream; separating the second byproduct gas stream into a carbon dioxide stream and an enriched nitrogen stream; and regenerating the second stage adsorption vessel using the enriched nitrogen stream.