Photocatalyst Extrudates for Low-Pressure-Drop Photoreactors
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Solution Overview
Problem
Existing photocatalytic reactors face challenges in scaling up for industrial chemical production due to limitations in pressure rating of glass-based pressure vessels, non-uniform irradiance, and mass transfer limitations, which hinder the optimization of photocatalyst size and gas flow rates, and there is a lack of understanding in designing photocatalytic reactors for gas-phase reactions.
Innovation Solution
The development of optimized photocatalyst extrudates with controlled shape and geometry, produced through co-precipitation, drying, mixing with binders and porogens, and extrusion, followed by thermal treatment, to create extrudates suitable for glass-based photoreactors, which enhance photocatalytic performance by minimizing pressure drop and maximizing active surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If glass-based pressure vessels are used for photoreactors, then light transmission is enabled, but pressure rating is limited
Solution Approach 1:
The system segments the pressure containment function from the light transmission function by introducing a transparent flexible membrane that transmits light while the external pressure vessel contains pressure. This allows glass or transparent flexible materials to be used for light transmission without being directly exposed to high pressure.
Solution Approach 2:
A transparent flexible membrane acts as an intermediary between the light source and the photocatalyst, and between the pressure environment and the reaction zone. This membrane transmits both light and mechanical stress, enabling pressure containment while maintaining optical access.
2Productivity
If photocatalyst particle size is increased to reduce pressure drop, then mass transfer is improved, but active surface area is reduced
Solution Approach 1:
The photocatalyst is formed as a porous monolith with interconnected pores that allow gas flow through the structure. This porous architecture provides high internal surface area for catalysis while maintaining macroscopic dimensions that reduce pressure drop across the reactor bed.
Solution Approach 2:
The photocatalyst transitions from zero-dimensional particles to a three-dimensional monolithic structure with hierarchical porosity. This dimensional change allows simultaneous optimization of surface area (through porous internal structure) and pressure drop (through macroscopic external dimensions).
3Productivity
If gas flow rate is increased to improve productivity, then production capacity is enhanced, but pressure drop increases
Solution Approach 1:
The porous monolith structure provides tortuous but continuous flow paths that reduce flow resistance. The hierarchical pore structure allows high gas flow rates while maintaining low pressure drop through optimized porosity and interconnected pore networks.
4Area of stationary object
If photocatalyst is used in powdered form, then active surface area is maximized, but reactor complexity increases
Solution Approach 1:
The photocatalyst is merged with a monolithic support structure to form an integrated photocatalytic monolith. This combination eliminates the need for separate catalyst particles and support materials, simplifying reactor design while maintaining high surface area through the porous structure.
Solution Approach 2:
The photocatalyst forms a composite monolithic structure where the active photocatalytic material is integrated into a mechanically robust monolith with controlled porosity. This composite architecture provides both high surface area and structural integrity for simplified reactor operation.
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 optimized extrudates enable efficient chemical reactions at lower temperatures using visible light, reducing energy consumption and carbon emissions, and allow for larger-scale industrial chemical production with improved photocatalytic performance and reduced reactor complexity.
Implementation Method 1
Photocatalysis, as used herein, refers to irradiating a chemical process with photons to accelerate the rate of chemical conversion of reactants to selectively form a desired product. Incident photons of sufficient energy and wavelength activate photo-induced reactions
Implementation Method 2
plasmonic nanoparticles that exhibit strong interactions with visible light due to the excitation of electronic oscillations
Implementation Method 3
co-precipitating at least two solutions to deposit an active metal on a support, thereby forming a slurry
Implementation Method 4
centrifugating the slurry to form a paste in which unreacted chemicals, byproducts, and excess solvent from the co-precipitating have been removed
Implementation Method 5
drying the paste to form a dried powder
Implementation Method 6
thermally treating the extrudate after drying
Data Source
AI summary
Methods and manufacturing processes for photocatalyst extrusion, extrudate photocatalysts, and photoreactor utilizing extrudate photocatalysts as a photocatalyst packed bed. An example method includes co-precipitating solutions to form a photocatalyst slurry, centrifugating and drying the slurry to form a dried powder, mixing the dried powder with a binder and a porogen and combining with a solvent to form a dough, feeding the dough through an extruder to create extrudates having a predetermined shape and cross-section, drying the extrudate, and thermally treating the extrudate after drying.