H2S Selective Membrane Separator for Syngas Purification
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Solution Overview
Problem
Integrated gasification combined-cycle (IGCC) power generation plants face inefficiencies in producing clean syngas due to the presence of hydrogen sulfide and carbon dioxide, which are not effectively removed from the raw syngas, affecting the combustion process and overall plant efficiency.
Innovation Solution
A carbon capture system incorporating an acid gas removal (AGR) subsystem, an H2S selective membrane separator, and a sulfur recovery unit (SRU) to separate hydrogen sulfide and carbon dioxide from the raw syngas, producing a lean gas and H2S-rich gas streams, thereby reducing impurities in the syngas fed to the gas turbine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acid gas removal is performed using conventional methods, then hydrogen sulfide and carbon dioxide are removed from raw syngas, but the process complexity and capital costs increase
Solution Approach 1:
The acid gas removal process is segmented into two distinct stages: first, an H2S-selective membrane separator removes hydrogen sulfide to produce H2S-lean syngas; second, an acid gas removal unit treats the H2S-lean syngas to remove carbon dioxide. This segmentation allows each unit to be optimized for its specific function, reducing overall process complexity while achieving effective acid gas removal.
Solution Approach 2:
The H2S-lean syngas stream serves as an intermediary between the membrane separator and the acid gas removal unit. By creating this intermediate stream with reduced H2S content, the subsequent CO2 removal process can be optimized without interference from high H2S concentrations, simplifying the overall process design and operation.
2Object-affected harmful factors
If conventional acid gas removal methods are used, then syngas is cleaned for combustion, but operating costs increase
Solution Approach 1:
The system discards H2S from the syngas stream through the membrane separator and recovers it as a concentrated H2S-rich stream suitable for sulfur recovery. Similarly, CO2 is discarded from the H2S-lean syngas in the acid gas removal unit. This selective discarding and recovery approach reduces operating costs by enabling efficient sulfur recovery and reducing the energy required for acid gas removal compared to conventional single-stage methods.
3Productivity
If hydrogen sulfide is not effectively removed from raw syngas, then the gasification process continues without additional separation steps, but combustion efficiency and environmental compliance deteriorate
Solution Approach 1:
The H2S-selective membrane separator performs preliminary H2S removal from raw syngas before the syngas enters the combustion system. This preliminary action reduces H2S content to levels that ensure reliable combustion and environmental compliance, while the continuous operation of the membrane separator maintains this protection without interrupting syngas production.
4Device complexity
If carbon dioxide is not removed from raw syngas, then the acid gas removal process is simplified, but environmental compliance and plant efficiency worsen
Solution Approach 1:
The removal of carbon dioxide is segmented as a separate stage following H2S removal. The acid gas removal unit is specifically designed to treat H2S-lean syngas, allowing it to be optimized for CO2 removal without the complications of high H2S content. This segmentation achieves effective CO2 removal while maintaining reasonable process simplicity through specialized unit design.
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 configuration enhances syngas production efficiency, reduces operating costs, and improves environmental compliance by continuously removing H2S and COS, leading to increased operational margins and reduced capital costs for IGCC plants.
Implementation Method 1
an H2S selective membrane separator oriented downstream from the AGR subsystem, the H2S selective membrane separator configured to separate the flow of H2S-lean gas from the AGR into a second flow of H2S-rich gas and a flow of CO2 gas
Implementation Method 2
an SRU configured to generate a flow of elemental sulfur and a flow of tail gas from the first flow of H2S-rich gas and the second flow of H2S-rich gas
Data Source
AI summary
A system and method of capturing carbon dioxide from a flow of raw synthesis gas generated in a gasification system are provided. The carbon capture system includes an acid gas removal subsystem configured to generate a flow of reduced acid gas content syngas, a flow of hydrogen sulfide (H2S) lean gas, and a first flow of H2S-rich gas from a stream of particulate-free raw syngas, an H2S selective membrane separator, said H2S selective membrane separator configured to separate the flow of H2S-lean gas from the AGR into a second flow of H2S-rich gas and a flow of CO2 gas, and a sulfur recovery unit (SRU) coupled in flow communication with said H2S membrane separator downstream of said membrane separator, said SRU configured to generate a flow of elemental sulfur and a flow of tail gas from the first flow of H2S-rich gas and the second flow of H2S-rich gas.