Multi-Zone Fluidised Bed Reactor for Cleaner Hydrocarbon Pyrolysis
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Solution Overview
Problem
Existing thermochemical reactors face issues with poor product quality due to high impurity levels, inefficient energy use, and operational challenges such as bed agglomeration, gas bypass, and feedstock delivery problems, particularly when processing plastics and biomass, leading to inefficient and costly processes.
Innovation Solution
A reactor design with multiple fluidised beds separated by gas distribution base plates, allowing improved mixing and control of temperature profiles, and a modular system for efficient thermochemical treatment of feedstock, including feedstock preparation and product refinement, to produce high-grade hydrocarbon products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single fluidised bed reactor is used for pyrolysis, then the process is simple to operate, but the product quality is poor with high impurity levels
Solution Approach 1:
The single fluidised bed reactor is segmented into multiple zones (devolatilization zone, cracking zone, and refining zone) separated by gas distribution base plates. Each zone performs a specific function: devolatilization removes volatiles, cracking breaks down hydrocarbons, and refining removes impurities. This segmentation allows complex product refinement functions to be integrated within a single reactor, improving product quality while maintaining operational simplicity.
2Productivity
If high temperatures are used for pyrolysis, then the conversion efficiency is improved, but energy costs increase and bed agglomeration occurs
Solution Approach 1:
Different temperature conditions are applied locally in different zones of the reactor. The devolatilization zone operates at high temperature for rapid volatile removal, the cracking zone operates at moderate temperature for controlled hydrocarbon breakdown, and the refining zone operates at lower temperature for impurity removal. This local quality approach optimizes conversion efficiency in each zone while reducing overall energy consumption and preventing bed agglomeration that would occur at uniformly high temperatures.
3Productivity
If plastics are fed directly into the hot bed, then the process is continuous, but feedstock delivery problems occur due to melting and blockage
Solution Approach 1:
The reactor design includes a devolatilization zone positioned above the gas distribution base plate where plastics are first fed and undergo preliminary thermal treatment. This preliminary action allows the plastic to be gradually heated and volatiles to be removed before the material enters the main hot bed, preventing sudden melting and blockage while maintaining continuous processing capability.
4Manufacturing precision
If extensive downstream catalytic upgrading is used, then the fuel product quality is improved, but the process becomes inefficient and costly
Solution Approach 1:
The patent merges the cracking and refining functions into a single integrated reactor system. The cracking zone performs hydrocarbon breakdown while the refining zone, positioned above the same gas distribution base plate, performs impurity removal in situ. This merging eliminates the need for separate downstream catalytic upgrading units, improving process efficiency while maintaining high fuel product quality through the combined action of multiple functional zones within one reactor.
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 achieves high-quality hydrocarbon products with reduced impurities and improved efficiency by enhancing mass and heat transfer, reducing energy costs, and enabling flexible processing of contaminated feedstocks.
Implementation Method 1
the devolatilization zone comprises a first gas distribution base plate for the generation of a fluidised bed of material in the devolatilization zone, the cracking zone comprises a second gas distribution base plate for the generation of a fluidised bed of material in the cracking zone
Implementation Method 2
Pyrolysis is the process of thermal destruction of hydrocarbons (e.g. polyolefins) in an oxygen-free environment at temperatures of 400-900 °C
Implementation Method 3
heat treatment of solid feedstock materials within a reactor to convert the solid feedstock into the desired more valuable product
Data Source
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AI summary
A reactor is described which is useful for the generation of hydrocarbon products by thermochemical treatment. The reactor comprises a feeding means for the addition of feedstock material to the reactor; an outlet for the extraction of hydrocarbon products from the reactor; a devolatilization zone; and a cracking zone; wherein the devolatilization zone comprises a first gas distribution base plate for the generation of a fluidised bed of material in the devolatilization zone, the cracking zone comprises a second gas distribution base plate for the generation of a fluidised bed of material in the cracking zone, and the devolatilization zone is in fluid communication with the cracking zone through a plurality of apertures within the second gas distribution base plate permitting the passage of gas from the devolatilization zone into the cracking zone. Processes of producing hydrocarbon products by thermochemical treatment are also described. The hydrocarbon products may be useful as drop-in fuel products and/or chemical feedstock.