Horizontal Steam Generator Tube Boundary Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Once-through steam generators face challenges in managing temperature imbalances and thermal stresses due to differences in mass flow and temperature between parallel tubes, particularly during startup and low-load operations, which can lead to operational risks and increased production costs.
Innovation Solution
The boundary between evaporator and superheater tubes is arranged essentially horizontally around the combustion chamber at the bottom of the horizontal gas pass, allowing the water separation system to function as a mixing point, reducing temperature imbalances and eliminating vertical separation points, thereby simplifying the design and enhancing operational safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the boundary between evaporator and superheater tubes is arranged vertically, then the structural design is simpler, but temperature imbalances and thermal stresses increase during startup and low-load operations
Solution Approach 1:
The patent transitions from a vertical arrangement of the boundary between evaporator and superheater tubes to a horizontal arrangement. This dimensional change allows the water separation system to function as a mixing point where flow from parallel tubes can equilibrate temperatures before entering the superheater section, thereby reducing thermal stresses and improving operational reliability during startup and low-load conditions.
2Adaptability or versatility
If parallel tubes have different mass flows and temperatures, then the steam generator can handle variable loads, but temperature imbalances increase causing thermal stresses
Solution Approach 1:
The water separation system serves as an intermediary mixing zone between the evaporator tubes and superheater tubes. Flow from multiple parallel evaporator tubes with different temperatures and mass flows is mixed in this intermediate region, allowing temperature equilibration before the combined flow enters the superheater section, thus reducing thermal stresses while maintaining load adaptability.
3Temperature
If additional mixing points are added to reduce temperature imbalances, then temperature distribution improves, but device complexity and production costs increase
Solution Approach 1:
The water separation system is designed to perform multiple functions: it separates water from steam during normal operation and simultaneously serves as a mixing point for temperature equilibration during startup and low-load operations. This multi-functionality eliminates the need for additional dedicated mixing points, maintaining temperature distribution improvement while avoiding increased device complexity and production costs.
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 arrangement reduces temperature differences, ensures safer and more reliable operation, extends the service life of the steam generator, and reduces material stresses, making the design more cost-effective and efficient.
Implementation Method 1
The water separator separates the water-steam mixture escaping from the evaporator tubes during start-up or during low-load operation into water and steam
Implementation Method 2
the supplied water flows in a number of tubes which absorb the energy in the form of radiant heat from the burner flames
Implementation Method 3
and/or by convection from the flue gas produced during combustion
Implementation Method 4
the heating of a number of evaporator tubes leads to a complete evaporation of the flow medium in the evaporator tubes in one pass
Implementation Method 5
the flow medium - usually water - after its evaporation is fed to superheater tubes downstream of the evaporator tubes and superheated there
Data Source
Figure 1
AI summary
The invention relates to a continuous steam generator (1) comprising a combustion chamber (2) having a number of burners for fossil fuels, downstream of which a vertical gas slope is mounted, on the hot gas side, in an upper region (4) above a horizontal gas slope (6). The outside wall (12) of the combustion chamber (2) is formed, in a lower region (10), from evaporation tubes welded together in a gas-tight manner and mounted upstream of a water separator system, on the flow medium side, and in an upper region (4), from superheater tubes welded together in a gas-tight manner and mounted downstream of the water separator system, on the flow medium side. The aim of the invention is to provide such a steam generator with an especially long service life and a comparatively simple structure. To this end, the limit (22) between the regions of the evaporation tubes and the superheater tubes is essentially horizontal around the combustion chamber (2), in the region of the bottom (18) of the horizontal gas slope (6).