Ammonia Oxidation Burner Sealing System for Bypass Prevention
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Solution Overview
Problem
In ammonia oxidation burners, the mechanical connection between the burner basket's wall and gas-permeable bottom plate leads to thermal expansion mismatches, causing gas bypass and potential decomposition of NO, as well as loss and misalignment of support materials, which reduces combustion efficiency and nitric acid production.
Innovation Solution
A sealing system with a moveable, segmented border seal made of metal sheets, anchored by guide pins, that bridges the gap between the wall and gas-permeable bottom plate, allowing for differential thermal expansion without mechanical force, ensuring a consistent seal across varying diameters and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the wall and gas-permeable bottom plate are mechanically joined to one another, then structural stability is improved, but thermal expansion mismatch causes gas bypass and decomposition of NO
Solution Approach 1:
The bottom plate is segmented into a fixed central region and a movable peripheral annular region. The movable region can independently expand radially outward relative to the wall, accommodating thermal expansion differences without compromising the gas seal. This segmentation allows the structure to maintain both stability and sealing integrity under thermal stress.
2Stress or pressure
If the gas-permeable bottom plate is laid loosely on internals, then thermal expansion stress is reduced, but a gap forms between the wall and bottom plate causing gas bypass
Solution Approach 1:
The peripheral annular region of the bottom plate is designed to be movable rather than fixed, allowing it to dynamically adjust its position during thermal expansion. This dynamic capability enables the plate to maintain contact with the wall throughout the expansion process, preventing gap formation and gas bypass while accommodating stress changes.
3Stress or pressure
If the burner basket expands at places covered with support materials, then localized thermal stress is reduced, but support materials may fall through the gap and lose function
Solution Approach 1:
The bottom plate's peripheral annular region is segmented and movable, creating a controlled interface that prevents support materials from falling through during expansion. The movable segments move in a coordinated manner that maintains the structural integrity of the support material bed while accommodating thermal expansion stresses.
4Ease of manufacture
If a one-piece burner basket construction is used, then manufacturing simplicity is improved, but high wear occurs due to heat stresses during start-up and shut-down
Solution Approach 1:
The bottom plate is divided into fixed and movable regions, allowing the movable peripheral region to independently accommodate thermal expansion during start-up and shut-down cycles. This segmentation protects the mechanical joint between the bottom plate and wall from excessive stress and wear, significantly improving component durability while maintaining manufacturing feasibility.
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 solution effectively prevents gas bypass and supports catalyst gauze materials, maintaining bed structure integrity and reducing ammonia loss, thereby enhancing combustion efficiency and nitric acid production by ensuring immediate cooling and stable NO processing.
Implementation Method 1
the wall (1) and the gas-permeable bottom plate (2) begin to expand to different degrees
Data Source
AI summary
A sealing system of a burner basket in an ammonia oxidation burner, wherein the burner basket has a wall that is anchored in the ammonia oxidation burner and the burner basket has a gas-permeable bottom plate, which is placed on further internal fittings of the ammonia oxidation burner and has a peripheral rim, wherein the wall and the gas-permeable bottom plate are not mechanically connected to each other, and so there is a gap between the wall and the peripheral rim of the bottom plate, wherein at the peripheral rim of the bottom plate a rim seal that is made up of individual segments is mounted movably by way of guiding pins and the rim seal projects over the gap between the peripheral rim of the bottom plate to the wall and lies against the wall.