Foam Bodies in Oxidation Reactors for Heat Dissipation
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Solution Overview
Problem
Conventional tube bundle reactors for the gas-phase oxidation of propene or isobutene to produce unsaturated aldehydes or carboxylic acids face limitations such as poor heat dissipation, high investment costs, complex catalyst filling procedures, and the formation of hot spots, which reduce selectivity and increase the risk of reactor runaway.
Innovation Solution
The use of open-cell, metallic or ceramic foam bodies in dehydrogenation and oxidation reactors allows for higher throughputs, increased catalyst service life, and larger tube diameters, enabling safer and more efficient production of unsaturated aldehydes or carboxylic acids without the need for multi-zone procedures or different catalyst beds, while using oxygen-enriched air or pure oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional tube bundle reactors with fixed bed catalysts are used for gas-phase oxidation, then production capacity can be maintained, but heat dissipation is poor leading to hot spots and reduced selectivity
Solution Approach 1:
The patent replaces conventional fixed bed catalysts with foam catalysts having a porous cellular structure. This foam structure provides vastly increased surface area for heat dissipation while maintaining catalytic activity, thereby eliminating hot spots and improving selectivity without sacrificing productivity.
Solution Approach 2:
The foam catalyst represents a composite material combining the catalytically active phase with a foam support structure. This composite architecture provides both the necessary catalytic function and superior thermal management through the high surface-area-to-volume ratio of the foam cells.
2Temperature
If tube bundle reactors with many small reaction tubes are used, then heat dissipation improves, but investment costs increase due to large number of tubes and complex catalyst filling
Solution Approach 1:
The foam catalyst's inherent porous structure eliminates the need for numerous small tubes by providing internal surface area for reaction and heat exchange within each tube. This simplifies reactor design while maintaining effective heat dissipation.
Solution Approach 2:
The foam catalyst introduces a new dimensional aspect (internal pore structure) for heat dissipation, replacing the need for multiple small tubes arranged in complex bundles. The heat exchange occurs throughout the three-dimensional foam structure rather than requiring numerous separate conduits.
3Duration of action of stationary object
If conventional fixed bed catalysts are used, then catalyst loading is straightforward, but catalyst service life is reduced due to hot spots and deactivation
Solution Approach 1:
The foam catalyst structure inherently resists hot spot formation due to its high surface area, extending catalyst life. The monolithic foam structure simplifies installation as a single piece or few large pieces rather than requiring filling of numerous small tubes with individual catalyst particles.
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 approach enhances space-time yield, reduces hot-spot temperatures, lowers investment costs, and maintains selectivity and conversion levels comparable to traditional methods with lower compressor capacity and pressure loss, thereby improving operational safety and efficiency.
Implementation Method 1
The foam body has a cell width in a range of 1 to 40 ppi, which facilitates heat dissipation and reduces hot-spot temperatures
Implementation Method 2
catalytic gas-phase oxidation of the unsaturated hydrocarbon obtained in process step i) or provided in process step ii) to obtain a gas mixture containing an unsaturated aldehyde in a first oxidation reactor having a first oxidation catalyst material
Implementation Method 3
at least one of the reactors selected from the dehydrogenation reactor, the first oxidation reactor and the second oxidation reactor contains at least one open-cell, metallic or ceramic foam body
Data Source
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AI summary
The present invention relates to a process for preparing unsaturated aldehydes or unsaturated carboxylic acids by heterogeneous catalytic gas phase oxidation of unsaturated or saturated hydrocarbons, comprising the process steps of: i) providing a gas mixture at least comprising a saturated hydrocarbon and catalytically dehydrogenating the at least one saturated hydrocarbon in the gas phase to obtain a gas mixture comprising an unsaturated hydrocarbon in a dehydrogenation reactor having a dehydrogenation catalyst material; or ii) providing a gas mixture at least comprising oxygen and at least one unsaturated hydrocarbon; iii) catalytically oxidizing the unsaturated hydrocarbon obtained in process step i) or provided in process step ii) in the gas phase to obtain a gas mixture comprising an unsaturated aldehyde in a first oxidation reactor having a first oxidation catalyst material; iv) optionally catalytically oxidizing the unsaturated aldehyde obtained in process step iii) in the gas phase to obtain a gas mixture comprising an unsaturated carboxylic acid in a second oxidation reactor having a second oxidation catalyst material; wherein at least one of the reactors selected from the dehydrogenation reactor, the first oxidation reactor and the second oxidation reactor comprises at least one foam body. The invention further relates to a process for preparing a polymer based on an unsaturated carboxylic acid, to an apparatus for preparing unsaturated carboxylic acids or a polymer based on unsaturated carboxylic acids, and to the use of an apparatus.