Axial Catalyst Bed Reactor With Floating Support for Thermal Stress
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Solution Overview
Problem
Existing reactors for nitric acid production suffer from high manufacturing costs, complexity, susceptibility to faults, and inefficiencies due to radial catalyst bed designs, which require costly flanges, complex sealing surfaces, and inadequate catalyst replacement methods, as well as thermal stress issues with axial flow configurations.
Innovation Solution
A reactor design with a catalyst bed that extends over the reactor cross-section and is flown through axially, featuring a floatingly mounted carrier structure with sieve elements and support elements that allow for simplified catalyst replacement and reduced thermal stress, eliminating the need for a main flange and catalyst settling reserves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial catalyst bed design is used, then the reactor can be sealed with flanges and have complex sealing surfaces, but this increases manufacturing costs, device complexity, and susceptibility to faults
Solution Approach 1:
The invention extracts and eliminates the flange and complex sealing surfaces from the reactor design by transitioning to an axial catalyst bed configuration, thereby reducing device complexity and susceptibility to faults while maintaining sealing integrity through a simpler structure
Solution Approach 2:
The invention inverts the conventional radial flow design to an axial flow configuration, where the gas stream flows through the catalyst bed in the axial direction rather than radially, fundamentally changing the reactor architecture to eliminate complex sealing requirements
2Productivity
If radial catalyst bed design is used, then catalyst replacement requires settling reserves and complex procedures, but this reduces productivity and increases loss of time
Solution Approach 1:
The invention extracts and eliminates the requirement for catalyst settling reserves by adopting axial flow configuration, allowing complete catalyst replacement without the need for reserve catalyst beds that would otherwise be required in radial designs
Solution Approach 2:
The invention enables preliminary preparation for catalyst replacement by designing the reactor with axial flow and removable catalyst beds, allowing catalyst to be replaced in advance or during scheduled maintenance without disrupting continuous operation and without requiring settling reserves
3Ease of manufacture
If axial catalyst bed configuration is used, then catalyst replacement is simplified, but thermal stress issues arise
Solution Approach 1:
The invention applies dynamics by allowing the catalyst bed to move axially within the reactor vessel, enabling the catalyst bed to expand and contract in response to thermal conditions while maintaining simplified replacement capability through axial displacement
Solution Approach 2:
The invention changes the operational parameters by controlling the axial position of the catalyst bed and adjusting flow conditions to manage thermal stress, allowing the system to adapt to thermal variations while maintaining ease of catalyst replacement
4Productivity
If radial flow through catalyst bed is used, then gas distribution is achieved, but bypassing occurs and manufacturing costs increase
Solution Approach 1:
The invention inverts the flow direction from radial to axial, eliminating bypassing pathways that exist in radial configurations and ensuring all gas streams pass through the catalyst bed in a controlled axial direction for complete treatment
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
This design reduces costs, simplifies maintenance, and enhances catalyst replacement efficiency while preventing bypassing and thermal stress, leading to a more reliable and cost-effective nitric acid production process.
Implementation Method 1
ammonia is catalytically oxidized to nitrogen oxides (NOx) using atmospheric oxygen
Implementation Method 2
ammonia is catalytically oxidized to nitrogen oxides (NOx) using atmospheric oxygen
Implementation Method 3
a temperature of about 800-950° C. being established at the meshes as a result of the exothermicity of the oxidation reaction
Implementation Method 4
a cooling is carried out, so that water present in the product gas stream condenses to form a first proportion of acid condensate
Implementation Method 5
the NOx gases are absorbed in water to form nitric acid (HNO3)
Implementation Method 6
ammonia which reacts with the nitrogen oxides remaining in the residual gas to afford nitrogen and water
Implementation Method 7
the NOx content is reduced by a catalytic reduction process
Data Source
AI summary
A reactor may have a catalyst bed for the catalytic treatment of a gas stream, with the catalyst bed extending substantially over a cross section of the reactor. Gas to be treated may axially fly through the catalyst bed. A carrier structure for the catalyst bed that is at least partly floatingly mounted in the reactor may include a sieve element and, radially outwardly, carrier elements fixedly joined to the reactor wall below the sieve element. The sieve element provides a resting surface for the catalyst bed. The sieve element terminates, radially outwardly, at a distance from the reactor wall. The carrier structure also includes support elements for the sieve element that are floatingly mounted in the reactor. An improved floating mounting is thus provided where not only the sieve element itself but also further parts of the carrier structure are mounted to prevent stresses due to thermal expansion.