Steam Turbine Bypass Valving for Single-SCR Combined-Cycle Operation
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Solution Overview
Problem
Current combined-cycle power plants face challenges in alternating between simple and combined-cycle operations while maintaining emissions compliance, as implementing a hot selective catalytic reduction (SCR) system with a diverter damper and bypass stack is costly, inefficient, and increases the plant's footprint.
Innovation Solution
A steam flow valving arrangement is used to direct steam from a heat recovery steam generator (HRSG) to either a condenser or a steam turbine system, depending on the operation mode, eliminating the need for a diverter damper and bypass stack, and utilizing a single SCR system downstream of the HRSG for emissions compliance in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a hot selective catalytic reduction (SCR) system is added with diverter damper and bypass stack to achieve emissions compliance in simple cycle mode, then emissions compliance is improved, but device complexity and capital cost increase significantly
Solution Approach 1:
The patent applies universality by enabling a single SCR system to serve dual purposes: treating exhaust during combined-cycle mode through the steam turbine, and treating exhaust during simple-cycle mode through the bypass arrangement. The steam turbine system is designed to handle both steam generation for power production and exhaust routing functions, eliminating the need for separate emissions control systems for each operational mode.
Solution Approach 2:
The patent merges the emissions control function into the existing combined-cycle infrastructure by integrating the SCR system downstream of the steam turbine. This consolidation allows the same exhaust treatment system to handle both operational modes, reducing overall system complexity and eliminating redundant components that would be required if separate SCR systems were installed for simple-cycle and combined-cycle operations.
2Object-generated harmful factors
If a hot selective catalytic reduction (SCR) system is added with diverter damper and bypass stack to achieve emissions compliance, then emissions compliance is improved, but construction cost and auxiliary load increase
Solution Approach 1:
The patent applies universality by enabling a single SCR system to serve dual purposes: treating exhaust during combined-cycle mode through the steam turbine, and treating exhaust during simple-cycle mode through the bypass arrangement. The steam turbine system is designed to handle both steam generation for power production and exhaust routing functions, eliminating the need for separate emissions control systems for each operational mode.
Solution Approach 2:
The patent merges the emissions control function into the existing combined-cycle infrastructure by integrating the SCR system downstream of the steam turbine. This consolidation allows the same exhaust treatment system to handle both operational modes, reducing overall system complexity and eliminating redundant components that would be required if separate SCR systems were installed for simple-cycle and combined-cycle operations.
3Object-generated harmful factors
If a hot selective catalytic reduction (SCR) system is added with diverter damper and bypass stack to achieve emissions compliance, then emissions compliance is improved, but plant footprint increases
Solution Approach 1:
The patent merges the emissions control function into the existing combined-cycle infrastructure by integrating the SCR system downstream of the steam turbine. This consolidation allows the same exhaust treatment system to handle both operational modes, reducing overall system complexity and eliminating redundant components that would be required if separate SCR systems were installed for simple-cycle and combined-cycle operations.
Solution Approach 2:
The patent applies universality by enabling a single SCR system to serve dual purposes: treating exhaust during combined-cycle mode through the steam turbine, and treating exhaust during simple-cycle mode through the bypass arrangement. The steam turbine system is designed to handle both steam generation for power production and exhaust routing functions, eliminating the need for separate emissions control systems for each operational mode.
4Object-generated harmful factors
If steam flow valving arrangement is used to direct steam to condenser during simple cycle operation, then emissions compliance is maintained with single SCR system, but steam turbine system must be bypassed
Solution Approach 1:
The patent applies dynamics by implementing a steam flow valving arrangement that dynamically routes steam based on operational mode. During simple-cycle operation, the valve directs steam to the condenser, bypassing the steam turbine. During combined-cycle operation, the valve redirects steam to the steam turbine for power generation. This dynamic switching capability allows the system to maintain emissions compliance while optimizing power generation based on operational requirements.
Solution Approach 2:
The patent extracts the steam turbine from the simple-cycle operational path by providing a bypass arrangement where steam can be directed to the condenser without passing through the steam turbine. This extraction allows the steam turbine to remain available for power generation during combined-cycle mode while eliminating its mandatory involvement in simple-cycle operation, thereby maintaining emissions compliance through the single downstream SCR system.
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 allows for flexible operation in both simple and combined-cycle modes with emissions compliance, reducing capital and operational costs, and maintaining efficiency by avoiding the need for multiple SCR systems.
Implementation Method 1
a heat recovery steam generator (HRSG) to generate steam from exhaust of the gas turbine system
Implementation Method 2
a condenser to condense steam from one of the steam turbine system and the HRSG
Data Source
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AI summary
A combined-cycle power plant (10) with a steam turbine bypass for simple cycle operation with a heat recovery steam generator (HRSG, 32) and a method of use are disclosed. In the disclosed combined-cycle power plant (10), a steam flow valving arrangement (34) is operatively coupled with the steam turbine (14), the HRSG (32), and a condenser (30). The steam flow valving arrangement (54) is configured to direct a flow of steam generated in the HRSG (32) to the condenser (30) bypassing the steam turbine (14) during a simple cycle mode of operation. In addition, the steam flow valving arrangement (54) is configured to direct the flow of steam generated in the HRSG (32) to the steam turbine (14) during a combined-cycle mode of operation.