SO2-Selective Membrane for Claus Tail Gas Treatment
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Solution Overview
Problem
Current sulfur recovery processes in Claus units face challenges in minimizing sulfur dioxide emissions without increasing energy consumption, equipment complexity, and capital costs, while maintaining high sulfur recovery efficiency.
Innovation Solution
A method involving the use of SO2-selective membranes and absorption processes in series to recover sulfur dioxide from Claus process outlet streams, utilizing a membrane sweeping unit with a sweep air stream to enhance separation and collection, and integrating a carbon dioxide membrane unit to reduce carbon dioxide in the feed, thereby optimizing sulfur recovery and minimizing SO2 emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional Claus process is used to convert H2S to elemental sulfur, then sulfur recovery is achieved, but sulfur dioxide emissions increase and energy consumption rises
Solution Approach 1:
The patent extracts sulfur dioxide from the Claus process outlet stream using a SO2-selective membrane. The membrane separates SO2 from the gas stream, allowing it to be removed and potentially reused in the Claus process, thereby reducing emissions without requiring additional energy-intensive treatment steps
Solution Approach 2:
The patent changes the physical state and concentration parameters of sulfur dioxide by using a selective membrane to separate and concentrate SO2 from the outlet stream. This allows for controlled removal and potential recycling, transforming the emission problem into a resource recovery opportunity while minimizing energy input
2Productivity
If multiple catalyst beds are used in the Claus unit to increase sulfur recovery efficiency, then sulfur recovery improves, but equipment complexity and capital costs increase
Solution Approach 1:
The patent applies preliminary action by removing sulfur dioxide from the outlet stream before it is released or further processed. By pre-separating SO2 using the selective membrane, the system achieves high sulfur recovery efficiency without requiring multiple catalyst beds, as the membrane performs the separation function upstream
Solution Approach 2:
The patent substitutes the mechanical system of multiple catalyst beds with a membrane-based separation system. The SO2-selective membrane replaces the need for additional catalytic conversion stages, simplifying the equipment while maintaining or improving sulfur recovery efficiency
3Object-generated harmful factors
If sulfur dioxide is removed from Claus outlet stream using conventional methods, then emissions are reduced, but operational costs and process complexity increase
Solution Approach 1:
The patent introduces an intermediary element: the SO2-selective membrane. This membrane acts as a mediator between the Claus process outlet stream and the emission control system, enabling selective SO2 removal through a single, integrated component rather than multiple complex treatment stages
Solution Approach 2:
The patent employs a thin-film selective membrane to achieve SO2 separation. This thin-film technology provides a compact, low-complexity solution for emissions control, replacing bulky conventional treatment equipment while maintaining effective sulfur dioxide 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 approach achieves sulfur recovery rates greater than 99.2% while reducing the number of catalyst beds in the Claus unit, minimizing SO2 emissions, and lowering operational and capital costs by simplifying the process and reducing energy usage.
Implementation Method 1
a sulfur dioxide-selective membrane to separate a portion of the sulfur dioxide from the Claus process outlet stream
Implementation Method 2
a sulfur dioxide-selective absorption process to separate sulfur dioxide from the membrane residue
Implementation Method 3
a thermal oxidizer to convert the sulfur-containing compounds and the hydrogen sulfide to sulfur dioxide
Implementation Method 4
a gas treatment unit to produce a process condensed water stream and a dehydrated stream
Data Source
AI summary
A method for recovering sulfur from an acid gas feed is provided. The method comprising the steps of mixing the acid gas feed and an absorption process outlet stream to form a combined Claus feed, introducing the combined Claus feed and a sulfur dioxide enriched air feed to a Claus process to produce a Claus outlet gas stream, introducing the Claus outlet gas stream to a thermal oxidizer, treating the thermal oxidizer outlet stream in a gas treatment unit to produce a dehydrated stream, introducing the dehydrated stream to a membrane sweeping unit to produce a sweep membrane residue stream and a sulfur dioxide enriched air feed, introducing a sweep air stream to a permeate side of the membrane sweeping unit, and introducing the sweep membrane residue stream to a sulfur dioxide absorption process to produce the absorption process outlet stream and a stack feed.