Microwave-Heated Fluidized Bed Reactor for Continuous Pyrolysis
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Solution Overview
Problem
Current plastic recycling methods are inefficient, leading to downcycling and high energy consumption, and existing microwave-assisted thermo-catalytic decomposition processes are limited by high energy requirements and batch processing, preventing economic scaling and uniform heating.
Innovation Solution
A microwave-heated fluidized bed reactor that converts hydrocarbon feedstocks, including plastics, into hydrogen deficient carbon products and hydrogen gas through a continuous flow process, utilizing a vertically oriented vessel with a distributor and microwave generator to achieve thermal uniformity and efficient conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microwave-assisted thermo-catalytic decomposition is used to produce hydrogen and carbon from plastics, then high hydrogen yield (～90%) is achieved, but high energy consumption and long processing time (about an hour) are required
Solution Approach 1:
The patent changes the processing mode from batch to continuous flow, and modifies operational parameters including reducing microwave power requirements through improved reactor design. This enables achieving high hydrogen yield with significantly reduced energy consumption and processing time (from about an hour to continuous operation with shorter residence times)
Solution Approach 2:
The patent transitions from batch processing to continuous flow processing, allowing the decomposition reaction to occur continuously rather than in discrete batches. This improves energy efficiency by maintaining steady-state operation and eliminates the need for repeated heating cycles, thereby reducing overall energy consumption while maintaining high hydrogen yield
2Quantity of substance
If batch processing is used for microwave-assisted decomposition, then high hydrogen yield is achieved, but long processing time and high energy consumption occur
Solution Approach 1:
The patent implements continuous flow processing where plastic feedstock is continuously fed into the reactor, decomposed under microwave irradiation, and products are continuously removed. This eliminates the start-stop nature of batch processing, reducing total processing time while maintaining high hydrogen yield through sustained reaction conditions
3Productivity
If conventional thermal decomposition is used, then processing can be scaled, but uneven heating and high energy consumption occur
Solution Approach 1:
The patent replaces conventional thermal conduction heating with microwave electromagnetic field heating. Microwaves provide volumetric heating throughout the reaction mixture, eliminating the uneven heating problems of conventional thermal methods. This substitution enables efficient scaling while reducing energy consumption through direct coupling of electromagnetic energy with the reaction medium
4Productivity
If conventional thermal decomposition is used, then processing can be scaled, but uneven heating occurs
Solution Approach 1:
The patent substitutes microwave electromagnetic heating for conventional thermal conduction heating. Microwaves penetrate the reaction mixture and provide uniform volumetric heating throughout the volume, eliminating the temperature gradients and hot/cold spots inherent in conventional thermal methods. This enables scalable processing while maintaining uniform heating conditions
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 reactor enables efficient production of hydrogen deficient carbon products, such as carbon nanotubes, with high thermal uniformity and reduced energy consumption, overcoming the limitations of batch processes and uneven heating in conventional methods.
Implementation Method 1
applying microwave energy to the mixture
Implementation Method 2
a distributor adapted to distribute the carrier gas into the interior of the lower portion of the vessel
Implementation Method 3
Microwave-assisted thermo-catalytic decomposition of plastics
Data Source
AI summary
A reactor including a vertically oriented vessel with a gas inlet port, a distributor, a feedstock port, and a microwave generator. The reactor is designed to process a carbon feedstock to produce hydrogen gas and a hydrogen deficient carbon product, utilizing a fluidized bed provided with microwave energy. Also disclosed are methods of converting a carbon feedstock, particularly a solid carbon feedstock, into hydrogen gas and a hydrogen deficient carbon product, preferably including carbon nanotubes.