Reactor Ring Baffle for Even Heat Distribution
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Solution Overview
Problem
Existing annular reactors using non-premixed burners face challenges with uneven heat distribution and local overheating of tubes due to high combustion gas momentum, leading to inefficiencies in endothermic reactions such as ammonia cracking and steam reforming.
Innovation Solution
The introduction of a ring baffle positioned on the opposite end wall of the combustion chamber, with specific dimensions and placement, redirects combustion gas for recirculation, increasing residence time and achieving more even heat distribution, thereby enhancing overall heat transfer and reducing tube wall temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If non-premixed burners are used in annular reactors, then heat input capacity is increased, but combustion gas momentum causes uneven heat distribution and local overheating of tubes
Solution Approach 1:
A ring baffle is introduced as an intermediary element between the combustion gases and the catalyst tubes. The baffle redirects the high-momentum combustion gases, forcing them to recirculate and lose momentum before reaching the tubes, thereby preventing direct impingement and local overheating while maintaining adequate heat transfer.
Solution Approach 2:
The ring baffle creates localized flow patterns that redirect combustion gases away from specific regions where direct impingement occurs. By modifying the flow field locally around the baffle, the system achieves more uniform heat distribution across the tube array without reducing overall heat input capacity.
2Power
If combustion gas momentum is high, then heat transfer rate is increased, but tubes experience local overheating due to direct impingement
Solution Approach 1:
The ring baffle acts as a mediator that decouples the high heat transfer rate from the harmful direct impingement effect. It allows the combustion gases to maintain their thermal energy while redirecting their flow path, so that heat is transferred to the tubes through recirculation rather than direct impact, preventing local overheating.
Solution Approach 2:
The high momentum of the combustion gases, which initially causes harmful direct impingement on the tubes, is converted into a beneficial recirculation flow pattern. The baffle redirects this momentum to create a circulating flow that enhances heat distribution uniformity while maintaining adequate heat transfer rates.
3Device complexity
If combustion gases exit directly through outlets adjacent to tubes, then gas flow is simplified, but heat distribution becomes uneven and tubes overheat
Solution Approach 1:
The ring baffle serves as an intermediary that modifies the gas flow path between the combustion chamber and the outlets. It forces the gases to recirculate through the combustion chamber before exiting, creating a more complex but beneficial flow pattern that ensures uniform heat distribution across all tubes.
Solution Approach 2:
The baffle performs a preliminary action by redirecting the combustion gases before they reach the tube outlets. This preliminary redirection ensures that heat has been distributed more uniformly across the tube array before the gases exit, preventing local overheating at the outlet regions.
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 implementation of the ring baffle improves heat transfer by up to 10% and reduces tube wall temperature by up to 100°C, leading to increased efficiency and reduced ammonia or methane slip in endothermic reactions.
Implementation Method 1
redirects combustion gas for recirculation, increasing residence time and achieving more even heat distribution
Implementation Method 2
combusting a fuel with an oxidant gas in the burner(s) to heat the catalyst-containing tubes
Implementation Method 3
Hot combustion gases provide heat mostly through radiation to the tubes
Implementation Method 4
Hot combustion gases provide heat mostly through radiation to the tubes
Implementation Method 5
The process is usually performed over a catalyst
Implementation Method 6
An endothermic reaction is a reaction that requires energy, usually heat energy, from the surroundings to provide the activation energy for the reaction to occur
Implementation Method 7
insulated cylindrical side wall having a first end and a second end opposite the first end
Data Source
AI summary
In a reactor comprising a cylindrical combustion chamber, at least one burner and a circular array of catalyst-containing tubes, there is provided a ring baffle on the wall opposite the burner(s) extending into the combustion chamber which redirects combustion gas around the combustion chamber, thereby enabling more even heat distribution and an increase in overall heat transfer.