Cooled Control Stopper for Waste Heat Boiler Exhaust
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Solution Overview
Problem
Current control stoppers in waste heat boilers are subject to high thermal loads, leading to the formation of hot plumes that cause thermal damage to the gas exhaust chamber walls, resulting in short servicing intervals and reduced lifespan.
Innovation Solution
A cooled control stopper that extends into the cone-shaped outlet end of the bypass pipe, with a radially expanding gas passage cross-section and a stopper base plate to deflect exhaust gases, combined with a cooling medium to prevent overheating and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a control stopper is arranged at the outlet end of the bypass pipe to control exhaust temperature, then the waste heat boiler gas exhaust temperature can be maintained within a particular temperature range, but hot plumes form causing thermal damage to the gas exhaust chamber walls
Solution Approach 1:
A cooling medium is introduced as an intermediary substance that flows through the stopper and mixes with the hot exhaust gases. This cooling medium acts as a mediator to reduce the temperature of the exhaust gases before they exit the bypass pipe, thereby preventing hot plume formation and thermal damage to the chamber walls while still allowing temperature control functionality.
Solution Approach 2:
The invention changes the temperature parameter of the exhaust gases by introducing a cooling medium. The cooling medium alters the thermal state of the exhaust flow, transforming it from a high-temperature state that causes thermal damage to a cooled state that prevents such damage, while maintaining the ability to control exhaust temperature within a desired range.
2Speed
If the exhaust gases flow through the bypass pipe at high velocity, then the control stopper is subject to high thermal load, but this high velocity flow creates powerful plumes that cause thermal damage
Solution Approach 1:
The cooling medium serves as an intermediary that mixes with the high-velocity exhaust gases in the bypass pipe outlet region. This mixing process reduces the temperature of the exhaust flow, thereby preventing the formation of hot plumes that would otherwise cause thermal damage to the chamber walls, even though the exhaust gases continue to flow at high velocity.
Solution Approach 2:
The invention converts the harmful high-temperature exhaust flow into a beneficial cooled flow by introducing the cooling medium. The high-velocity flow that previously created damaging hot plumes is now combined with the cooling medium to create a mixed flow that maintains velocity while reducing temperature, thereby eliminating the thermal damage problem.
3Temperature
If a control stopper is used to influence exhaust temperature, then the gas exhaust temperature can be controlled, but the stopper itself is subject to thermal corrosion
Solution Approach 1:
The cooling medium acts as an intermediary protective layer that flows through the stopper and cools the stopper surface. This intermediary cooling flow protects the stopper from direct exposure to the high-temperature exhaust gases, thereby preventing thermal corrosion and extending the service life of the control stopper while maintaining its temperature control functionality.
Solution Approach 2:
The cooling medium provides beforehand cushioning by pre-cooling the exhaust gases and the stopper surface before the hot exhaust flow can cause thermal damage. This prior cooling action cushions against the thermal load, protecting the stopper from thermal corrosion and extending its operational life.
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
Prevents hot plumes from forming, reduces thermal corrosion, and extends the lifespan and servicing intervals of the waste heat boiler by decelerating exhaust gas velocity and dissipating gas plumes, thereby protecting the chamber walls.
Implementation Method 1
the stopper may be cooled by a cooling medium
Implementation Method 2
the gas passage cross-section expands uniformly or non-uniformly in the direction of flow of the exhaust gas flow within the gas passage area
Implementation Method 3
the stopper, viewed in the flow direction of the exhaust gas stream, is implemented with a stopper base plate that extends radially opposite the center portion of the stopper to deflect the exhaust gas stream in a maximally radial direction
Data Source
AI summary
A waste heat boiler includes an axial bypass pipe and multiple heat transfer pipes disposed within a cylindrical jacket. A hot exhaust gas stream transported between inlet and outlet ends of the heat transfer pipes is cooled by a coolant. A control system controls gas passage velocity and quantity of the exhaust gas stream through the bypass pipe whereby the exhaust gas stream exhaust temperature is maintained within a predetermined temperature range. The control system includes a stopper disposed at the outlet end of the bypass pipe and has a head plate extending into the outlet end of the bypass pipe. The stopper is axially displaceable from a closed position, where an outer surface of the stopper head plate contacts an inner surface of the bypass pipe outlet end. The gas passage formed between the inner surface of the bypass pipe outlet end and the outer surface of the stopper head plate has a cross-section that increases as the stopper is axially displaced from the closed position. The stopper is cooled by a cooling medium.