High Temperature Desulfurization and Water-Gas Shift for Syngas Cleaning
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Solution Overview
Problem
Current methods for removing sulfur compounds and converting carbon monoxide to carbon dioxide in syngas streams are inefficient and costly, leading to reduced thermal value and increased capital expenditures in combined cycle power plants, with existing acid gas removal processes requiring cooling and solvent-based systems that incur energy losses and high operational costs.
Innovation Solution
A method combining high temperature desulfurization with multiple water-gas shift reactions and hydrogen separation using a hydrogen permeable membrane to remove sulfur compounds and convert carbon monoxide to carbon dioxide, eliminating the need for solvent-based acid gas removal processes and achieving nearly complete conversion of carbon monoxide to carbon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvent-based acid gas removal processes are used to remove sulfur compounds and CO2 from syngas, then sulfur and CO2 removal is achieved, but the process requires cooling to low temperatures and uses expensive solvents resulting in high energy consumption and operational costs
Solution Approach 1:
The patent changes the temperature parameter from conventional low-temperature operation to high-temperature operation (above 200°C). This allows the use of water-gas shift reactions and high-temperature desulfurization processes that eliminate the need for cooling and conventional solvent-based systems, thereby reducing energy consumption while maintaining removal efficiency
Solution Approach 2:
The patent replaces the mechanical/physical solvent absorption system with chemical reaction-based systems. Specifically, it uses water-gas shift reactions (CO + H2O → CO2 + H2) and high-temperature desulfurization chemistry to remove sulfur and CO2, eliminating the need for physical solvents and associated cooling machinery
2Reliability
If conventional acid gas removal processes are used, then sulfur compounds are removed, but the process complexity and capital expenditures increase due to multiple equipment components and solvent handling systems
Solution Approach 1:
The patent merges multiple separate functions into integrated reaction zones. The water-gas shift reactions and desulfurization processes occur in combined high-temperature reaction sections, eliminating the need for separate cooling systems, solvent recovery units, and multiple treatment stages, thereby simplifying the overall process
Solution Approach 2:
The patent extracts and eliminates the solvent-based acid gas removal section entirely. By removing this complex subsystem and replacing it with direct chemical conversion processes, the patent reduces equipment complexity while maintaining sulfur removal effectiveness
3Use of energy by moving object
If high temperature desulfurization is used to remove sulfur compounds, then sulfur removal efficiency improves and energy consumption decreases, but the process requires multiple water-gas shift reactions to achieve complete CO conversion
Solution Approach 1:
The patent segments the CO conversion process into multiple sequential water-gas shift reactions operating at different temperatures. This segmentation allows each reaction stage to optimize for specific conversion requirements, achieving complete CO to CO2 conversion while managing the overall process complexity through systematic staging
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 results in a more efficient and cost-effective syngas cleaning process, reducing residual sulfur and carbon monoxide levels, enhancing thermal efficiency, and producing a clean hydrogen-based fuel source for combined cycle plants without the need for catalytic converters or solvent-based systems.
Implementation Method 1
separating out substantially all hydrogen present in the treated synthesis gas stream
Implementation Method 2
converting carbon monoxide to carbon dioxide through a series of water-gas shift reactions
Data Source
AI summary
A method and system for capturing and isolating carbon dioxide and hydrogen gases from a high temperature synthesis gas stream containing a substantial amount of CO and sulfur compounds for use as a “clean” supplemental fuel, comprising the steps of reducing the temperature of the high temperature synthesis gas stream, removing substantially all of the sulfur compounds present in the synthesis gas, converting a first portion of CO to carbon dioxide in a first high temperature water-gas shift reaction, converting a second portion of CO to carbon dioxide using a second low temperature water-gas shift reaction, converting a third portion of CO to carbon dioxide using a third low temperature water-gas shift reaction and then separating out substantially all hydrogen present in the treated synthesis gas stream.