Heat Recovery Steam Generator Flash Evaporation Segmentation
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Solution Overview
Problem
Conventional heat recovery steam generators are costly and inefficient, particularly in the low-pressure regime, due to the need for large steam piping and inability to provide multiple steam pressures, which reduces energy efficiency and increases structural complexity.
Innovation Solution
A heat recovery steam generator system utilizing a first pressure section with a flash vessel for steam generation by flash evaporation, allowing for multiple steam pressures and reduced piping requirements, along with additional pressure sections for efficient thermal energy transfer, and incorporating a water turbine for enhanced energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional heat recovery steam generators use direct contact evaporation in tubes for steam generation, then the structural setup is relatively simple, but the energy efficiency is reduced and the ability to provide multiple low pressure steams is limited
Solution Approach 1:
The steam generation process is divided into multiple pressure sections (first pressure section for low pressure steam, second pressure section for high pressure steam), each with dedicated economizer, evaporator, and superheater sections. This segmentation allows optimized heat recovery at different pressure levels, improving energy efficiency while maintaining structural clarity through modular design.
Solution Approach 2:
The patent introduces a third dimension to heat transfer by using a heat transfer fluid that circulates through tubes in direct contact with exhaust gas, while steam is generated in separate chambers. This indirect heat transfer approach adds a fluid circulation dimension, enabling better thermal efficiency and multiple steam pressure outputs without proportionally increasing structural complexity.
2Adaptability or versatility
If steam piping dimensions increase to accommodate lower steam pressures, then more low pressure steam can be provided, but the piping grows in dimensions and structural complexity increases
Solution Approach 1:
The system is segmented into multiple pressure sections, each generating steam at specific pressure levels. The first pressure section produces low pressure steam (2-35 bar) and the second pressure section produces high pressure steam (>70 bar), eliminating the need for large-diameter piping to transport low pressure steam over long distances. Each section has its own compact steam generation and distribution system.
Solution Approach 2:
Each pressure section has locally optimized components including dedicated economizer, evaporator, and superheater sections tailored to its specific pressure and temperature requirements. This local optimization allows each section to be compact and efficient, reducing overall piping complexity while providing versatile multi-pressure steam output.
3Loss of energy
If multiple pressure sections with economizer, evaporator, and superheater are added, then energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The heat recovery steam generator is divided into functionally independent but structurally integrated pressure sections. Each section contains economizer, evaporator, and superheater components arranged in sequence, allowing modular manufacturing and assembly. This segmentation enables optimized heat recovery at each stage while maintaining manageable structural complexity through standardized modular units.
Solution Approach 2:
The heat transfer fluid circulation system serves multiple functions simultaneously: it absorbs heat from exhaust gas in the evaporator section, transfers heat to water in the economizer section, and provides superheating in the superheater section. This multi-functionality reduces the need for separate systems for each function, balancing improved energy efficiency with controlled structural complexity.
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
The system achieves improved energy efficiency and reduced structural complexity by generating steam at multiple pressures with smaller piping, enhancing the performance of the steam turbine and overall energy recovery from exhaust gas.
Implementation Method 1
a first pressure section (20) having a flash vessel (24) for generating steam (50) out of feed water (42) by flash evaporation
Implementation Method 2
arranged thermally coupled to a flow of exhaust gas (40)
Implementation Method 3
a water turbine (26) is arranged in the flow of feed water (42) in the flow direction of the feed water (42) before the at least one flash vessel (24) to deliver feed water (42) to the at least one flash vessel (24)
Data Source
Figure 1
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AI summary
The invention is directed to a heat recovery steam generator (3) for generating steam (50) for a steam turbine (2) by recovering heat energy out of a flow of exhaust gas (40), comprising a first pressure section (20) for producing steam (50) at a first pressure. Further, the invention is directed to a method for generating steam (50) for a steam turbine (2) in a heat recovery steam generator (3). Additionally, the invention is directed to a system (1), comprising a steam turbine (2) and a heat recovery steam generator (3), the heat recovery steam generator (3) providing steam (50) for the steam turbine (2).