Carbon Nanostructure Fluidized Bed Reactor Continuous Production
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Solution Overview
Problem
Existing methods for producing carbon nanostructures in fluidized bed reactors face challenges such as aggregation, poor mixing of catalyst and gas, and short contact time, leading to inefficient growth and yield of carbon nanostructures due to the upward gas flow, which results in clogging and pressure drops, and batch-type methods are time- and cost-inefficient.
Innovation Solution
A method where a predetermined amount of uncollected carbon nanostructures are left as fluidic materials in the reactor to enhance fluidity and contact time between the catalyst and carbon source, optimizing the residual rate and catalyst supply to ensure continuous production of carbon nanostructures with improved conversion efficiency and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If upward gas flow is used in fluidized bed reactor, then gas distribution is improved, but carbon nanostructures aggregate and settle on distribution plate
Solution Approach 1:
The patent introduces a downward gas flow through the distribution plate instead of the conventional upward flow. This inverted flow direction prevents carbon nanostructures from settling on the distribution plate by carrying them back into the fluidized bed, thereby maintaining stable dispersion while still achieving effective gas distribution throughout the reactor.
Solution Approach 2:
The patent uses a fluidic material (inert gas) as an intermediary to enhance the fluidity of the carbon nanostructure-catalyst mixture. This intermediary fluid helps maintain suspension of carbon nanostructures and prevents aggregation, allowing the system to benefit from both good gas distribution and stable nanostructure composition.
2Productivity
If catalyst and carbon source have short contact time, then productivity is improved, but conversion efficiency decreases
Solution Approach 1:
The patent dynamically adjusts the residence time of catalyst and carbon source in the fluidized bed by controlling gas flow rates and bed expansion. The system maintains optimal contact time for high conversion efficiency while ensuring continuous product removal to sustain productivity, creating a dynamic balance between these conflicting parameters.
Solution Approach 2:
The patent implements continuous operation where catalyst, carbon source, and fluidic material flow continuously through the reactor. This continuous action ensures that conversion processes never stop while maintaining optimal contact time, thereby achieving both high conversion efficiency and sustained productivity without batch interruptions.
3Ease of operation
If carbon nanostructures are not removed from reactor, then fluidity is improved, but reactor volume is occupied
Solution Approach 1:
The patent changes the physical state and properties of carbon nanostructures by controlling residence time, temperature, and gas flow parameters. These parameter changes allow carbon nanostructures to maintain fluidity and remain suspended in the fluidized bed without settling, effectively utilizing reactor volume while preserving operational fluidity.
Solution Approach 2:
The patent uses fluidic material (inert gas) as a copying medium that replicates the fluidization behavior of the carbon nanostructure-catalyst mixture. This fluidic copy enhances the overall fluidity of the system without occupying additional reactor volume, as it integrates seamlessly with the existing phases.
4Adaptability or versatility
If batch type production is used, then catalyst can be replaced, but heating time and cost increase
Solution Approach 1:
The patent implements continuous catalyst circulation and replacement within the fluidized bed system. Fresh catalyst can be continuously introduced while spent catalyst is removed, eliminating the need for batch shutdowns and cooling/heating cycles. This continuous operation maintains constant reaction temperature, thereby eliminating additional heating time and associated costs while preserving catalyst adaptability.
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 allows for continuous production of carbon nanostructures with extended contact time, improved fluidity, and high conversion efficiency, eliminating the need for subsequent separation and reducing operational inefficiencies, resulting in high-purity products with optimized physical properties.
Implementation Method 1
the gas flows upwardly through the distribution plate to allow a particle bed on the distribution plate to float in a fluidized state
Implementation Method 2
carbon nanostructures tend to aggregate and settle down on the upper surface of the distribution plate due to their strong van der Waals attractive force
Implementation Method 3
carbon nanostructures are typically formed by dispersing and reacting metal catalyst particles and a gaseous hydrocarbon raw material in a fluidized bed reactor at a high temperature
Data Source
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AI summary
The present invention relates to a method for producing carbon nanostructures using a fluidized bed reactor. According to the method, some of the as-produced carbon nanostructures remain uncollected and are used as fluidic materials to improve the fluidity in the reactor. The method enables the production of carbon nanostructures in a continuous process. In addition, the fluidity of the catalyst and the fluidic materials in the reactor is optimized, making the production of carbon nanostructures efficient.