Fluidized Bed Reactor with Separation Filter for Nanoparticle Deposition
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Solution Overview
Problem
Fluidized bed reactors struggle with efficiently fluidizing particles that do not obey Ergun's equation, particularly ultra-low density powders like diatomite, which hinders 100% functionalization through gas phase reactions such as atomic layer deposition, and lacks fine control over nanoparticle size dispersion due to external gas transport and turbulent fluid mechanics.
Innovation Solution
A high-temperature resistant and transparent quartz tube fluidized bed reactor with separate upstream and downstream zones, porous filters, and a heating source, allowing for precise control of gas flow and temperature for in situ vapor phase impregnation of nanoparticles onto powders, enabling efficient fluidization and functionalization of particles like diatomite for atomic layer deposition and carbon nanotube growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard fluidized bed reactor is used for ultra-low density powders like diatomite, then the reactor structure is simple, but the fluidization control is poor and particles cannot be efficiently functionalized
Solution Approach 1:
The reactor tube is divided into three distinct zones: a fluidization zone for particle suspension, a deposition zone for nanoparticle coating, and a separation filter zone for particle collection. This segmentation allows independent optimization of fluidization control in the first zone while maintaining structural simplicity overall.
Solution Approach 2:
A separation filter is introduced as an intermediary component between the fluidization zone and deposition zone. This filter mediates the transition of particles from fluidized state to collected state, enabling precise control over fluidization parameters without requiring complex reactor redesign.
2Manufacturing precision
If external gas transport is used for particle functionalization, then the process is simple, but nanoparticle size dispersion control is poor
Solution Approach 1:
The functionalization process is segmented into distinct spatial zones: fluidization zone for particle suspension, deposition zone for controlled nanoparticle coating, and separation zone for particle collection. This segmentation enables precise control of nanoparticle size dispersion in the deposition zone through controlled vapor phase impregnation.
Solution Approach 2:
The external gas transport mechanism is replaced with in-situ vapor phase impregnation within the fluidized bed. This substitution eliminates the need for complex external transport systems while achieving superior nanoparticle size dispersion control through direct vapor deposition onto fluidized particles.
3Reliability
If wet impregnation is used for surface coating, then the coating process is simple, but the functionalization completeness is insufficient
Solution Approach 1:
The coating process utilizes phase transition from vapor to condensed phase through vapor phase impregnation. Precursor materials are vaporized and then condensed onto the surface of fluidized particles, achieving complete and uniform functionalization that surpasses wet impregnation methods.
Solution Approach 2:
Wet impregnation is replaced with vapor phase impregnation methodology. This substitution eliminates liquid handling complexity while achieving superior functionalization completeness through vapor-phase chemical reactions that occur uniformly across all particle surfaces in the fluidized state.
4Adaptability or versatility
If conventional CVD is used for coating, then the process is straightforward, but individual adjustment of precursor concentration and residence time is limited
Solution Approach 1:
The reactor is segmented into distinct zones that allow independent control of process parameters. The deposition zone specifically enables individual adjustment of precursor concentration and residence time by controlling vapor generation rate and particle residence time in the coating region, providing adaptability without overall reactor complexity.
Solution Approach 2:
The system incorporates dynamic control capabilities where gas flow rates, temperature, and precursor delivery can be independently adjusted during operation. This allows real-time optimization of precursor concentration and residence time parameters to achieve desired coating characteristics.
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 configuration allows for flexible control over impregnation and fluidization, achieving uniform and conformal coatings of nanoparticles on powders, enabling the growth of carbon nanotubes on mesoporous supports with precise control over morphology and process parameters, enhancing the functionality of particles within the reactor.
Implementation Method 1
said upstream zone of said tube being connected to a heating part (18) and adapted to comprise the solid precursor or precursor powder to be sublimated (26)
Implementation Method 2
A flow of gas is passed through a solid substrate at high enough velocities to suspend the solid and cause it to behave as though it were a fluid (fluidization)
Implementation Method 3
The ALD process can be performed in wide range of temperatures starting from room temperature
Data Source
Figure 1
AI summary
The first object of the invention is directed to a fluidized bed reactor designed for in situ gas phase impregnation. The reactor comprises a tube (2) with an upstream zone and a downstream zone, said upstream zone and said downstream zone being separated by a separation filter (14). The second object of the invention is directed to a method for a controlled-deposition of a sublimated precursor onto a fluidized solid support. Said method is remarkable in that it is carried out in situ within the tube (2) of the fluidized bed reactor in accordance with the first object of the invention.