Modular Catalyst Monoliths for Thermal Expansion Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-temperature reactors with catalytic monolithic shaped bodies face issues due to thermal expansion differences between the reactor materials and the catalytic or non-catalytic particles, leading to inhomogeneous fillings, reduced catalytic efficiency, and increased risk of particle breakage and emissions, particularly in processes for producing nitrogen oxides and nitric acid.
Innovation Solution
A reactor design with a device featuring a perforated metal base and side boundaries made from high-temperature materials like Inconel 600 or Alloy 602 CA, incorporating a heat-insulating layer and modular structured catalyst bodies to minimize thermal expansion issues and ensure efficient, damage-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If monolithic shaped bodies are used as catalytic fillings in high-temperature reactors, then catalytic efficiency is improved, but the bodies are susceptible to breakage and destruction due to thermal expansion differences and mechanical stress
Solution Approach 1:
The device is divided into multiple segments or modules that can expand and contract independently. Each segment contains monolithic shaped bodies that are supported within confined spaces, preventing them from moving freely and breaking due to thermal expansion differences between the reactor materials and the monolithic bodies.
Solution Approach 2:
A metal mesh or support structure is introduced as an intermediary between the monolithic shaped bodies and the reactor walls. This intermediary layer absorbs and distributes the mechanical stress caused by thermal expansion, protecting the brittle monolithic bodies from direct contact forces that would cause breakage.
2Productivity
If the reactor operates at high temperatures to improve reaction rates, then productivity increases, but thermal expansion differences cause inhomogeneous filling and reduced catalytic performance
Solution Approach 1:
The reactor is segmented into multiple zones with independent support structures. Each segment maintains uniform catalyst distribution locally, preventing the formation of large-scale inhomogeneities that would occur in a continuous structure subjected to thermal expansion.
Solution Approach 2:
The support structure parameters (mesh size, spacing, material properties) are specifically designed to accommodate thermal expansion at operating temperatures. The metal mesh or support elements are selected with thermal expansion coefficients that match the reactor materials, maintaining consistent spacing and preventing catalyst displacement during temperature cycles.
3Ease of repair
If the reactor is shut down for repairs or maintenance, then operational issues can be addressed, but replacing monolithic catalytic elements is tedious and inefficient
Solution Approach 1:
The catalytic system is divided into modular segments that can be independently removed and replaced. Each module contains the monolithic shaped bodies mounted on a common support structure, allowing entire modules to be swapped out as units rather than handling individual brittle monolithic bodies one by one.
Solution Approach 2:
The monolithic shaped bodies are nested within or mounted on removable carrier structures or cages. These carriers protect the fragile monolithic bodies during handling and allow them to be installed or removed as protected units, reducing the time and risk associated with replacing catalyst elements.
4Adaptability or versatility
If monolithic shaped bodies are removed from or inserted into the receiving device, then catalyst replacement is possible, but there is a risk of breakage of the molded parts
Solution Approach 1:
Protective carrier structures or cages serve as intermediaries during the installation and removal processes. These carriers provide mechanical support and protection to the brittle monolithic shaped bodies, preventing breakage during handling, transport, and installation while still allowing the catalyst to function when in place.
Solution Approach 2:
The monolithic shaped bodies are pre-mounted and secured to removable carrier structures before being inserted into the reactor. This preliminary assembly ensures proper positioning and provides protection during handling, eliminating the risk of breakage that would occur if the bodies were handled individually during installation.
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 enhances catalytic efficiency by maintaining a stable reactor environment, reducing nitrous oxide emissions, and allowing for easier maintenance and replacement of catalyst bodies, thereby improving overall production processes for nitrogen oxides and nitric acid.
Implementation Method 1
incorporating a heat-insulating layer and modular structured catalyst bodies to minimize thermal expansion issues
Implementation Method 2
processes for the production of nitrogen oxides and/or nitric acid by the oxidation of ammonia in the presence of a catalyst, such as a precious metal-containing catalyst mesh
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a reactor (R) with a device (D) containing a gas and/or liquid-permeable base (B) in whose edge region a lateral boundary (W) is arranged which entirely surrounds the base (B) and forms a volume (V), said volume containing catalytic and/or non-catalytic moulded bodies (F), wherein at least one mesh made of noble metal and/or non-noble metal is located on the side opposing the base (B) in the upstream direction, and the catalytic and/or non-catalytic moulded bodies (F) are selected from (i) moulded bodies (F1) in the form of straight prisms whose base surface is selected from a triangle, rectangle, hexagon or fragments of these polygons, or (ii) a combination of the moulded bodies (F1) with moulded bodies (F2) that are smaller than the moulded bodies (F1), characterised in that groups of m to n moulded bodies (F1), where m/n is a whole number between 3-30 and n > m, are bound to form modules (M) in a metal cassette that is open upstream and closed with a gas-permeable base in the downstream direction, with their lateral surfaces side by side practically without a gap and with their longitudinal axis oriented in the vertical direction, such that the cross-section of the base is practically entirely covered, and which modules (M) are joined to one another in a mosaic-like manner practically without a gap, with the vertical orientation of the longitudinal axis of the moulded bodies (F1), optionally with the cooperation of a joint filling material.