Rim-Based Catalyst Support for Ammonia Oxidation Burners

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Solution Overview

Problem

Existing catalyst support structures for ammonia oxidation burners are prone to thermal stress-induced failure due to large temperature differences, leading to cracking and ammonia leakage, which reduces efficiency and poses explosion risks.

Innovation Solution

A rim-based catalyst support system with a top flange and inner wall, featuring a planar section, rounded edges, and expansion slits, designed to accommodate thermal strain with uniform thickness and curvature ratios, reducing the number of welds and enhancing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional catalyst support structures are used, then the burner can perform ammonia oxidation, but thermal stresses cause cracking and structural failure

Engineering Contradiction:

Improvestructural integrityVSAvoidresistance to thermal stress

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The rim is designed with a specific geometric configuration including a rounded outer edge, rounded inner edge, and planar section with controlled radius of curvature. This flexible geometric design allows the rim to accommodate thermal expansion and contraction during transient conditions, preventing crack formation while maintaining structural integrity under thermal stress

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention specifies precise geometric parameters for the rim including the radius of curvature of the rounded edges and the width of the planar section. By optimizing these parameters, the rim can effectively distribute and accommodate thermal stresses, preventing the cracking that occurs in traditional rigid support structures

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If multiple welded connections are used to assemble the burner basket, then the structure can be constructed, but the welded connections create weak links prone to rupture

Engineering Contradiction:

Improveassembly capabilityVSAvoidresistance to rupture

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The rim is designed as an integrated component that combines multiple functions into a single structural element. This integration reduces the number of separate parts and welded connections required, thereby eliminating weak links while maintaining assembly capability through the rim's inherent structural design

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rim is divided into distinct geometric sections (rounded outer edge, planar section, rounded inner edge) that can be manufactured separately and then assembled with minimal welding. This segmentation allows for easier manufacturing while reducing the total number of welded connections compared to traditional designs

Inventive Principle:

Principle #1Segmentation

3Reliability

If the rim has complex geometric features, then thermal stress accommodation is improved, but manufacturing difficulty increases

Engineering Contradiction:

Improvethermal stress resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The rim incorporates rounded edges with specified radius of curvature instead of sharp corners. This curvature design accomplishes two things: it stress-concentrations are eliminated improving thermal stress resistance, and the rounded geometry is easier to manufacture using standard forming processes compared to sharp angular features

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 rim effectively mitigates thermal stresses, extending the lifespan of ammonia burner baskets, reducing ammonia bypass, and ensuring a uniform gas flow, while being easier to manufacture and maintain.

Implementation Method 1

large temperature differences that may even be greater than 500° C. between relatively hot catalyst support structures and relatively cold reactor walls result in differences in thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

These differences need to be accommodated in order to prevent the occurrence of unacceptably large thermal stresses

Methodology Applied

Scientific EffectThermal stress: Thermal Shock

Implementation Method 3

the rim effectively mitigates thermal stresses, extending the lifespan of ammonia burner baskets

Methodology Applied

Scientific EffectThermal stress resistance: Thermal Shock

Data Source

PatentUS11485639B2Catalyst support systems for ammonia oxidation burners

Publication Date: 2022.11.01 YARA INTERNATIONAL ASA

AI summary

Catalyst support systems for ammonia oxidation burners comprising a top flange and an inner wall. The top flange comprises a planar section, a rounded outer edge, and a rounded inner edge, the rounded outer edge and the rounded inner edge being separated by the planar section. The inner wall comprises a carrier plate, a gauze shelf, and a bottom plate shelf, the gauze shelf and the bottom plate shelf being attached to the carrier plate. The carrier plate is attached to the top flange by means of the rounded inner edge.