Forced-Circulation Pyrolysis Reactor for Coke Fouling Control
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Solution Overview
Problem
Conventional hydrocarbon pyrolysis methods face challenges with carbon deposition on reactor surfaces, leading to equipment fouling and low-value carbon product formation, limiting commercial scalability and efficiency.
Innovation Solution
A forced circulation reactor system is employed to maintain a threshold solids density of coke particles within the pyrolysis environment, utilizing fluidized beds to preferentially deposit carbon on circulating particles, minimizing deposition on reactor surfaces and enhancing the recovery of larger, higher-value carbon products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional pyrolysis methods are used, then carbon is produced as a byproduct, but carbon deposits on reactor surfaces causing equipment fouling and low-value carbon formation
Solution Approach 1:
The patent introduces inert solid particles as intermediaries that serve as preferential deposition sites for pyrolysis carbon. These particles circulate through the reactor, capturing carbon that would otherwise deposit on reactor surfaces. The particles act as a mediator between the pyrolysis reaction and the carbon product, redirecting carbon deposition away from equipment and toward collectible particles.
Solution Approach 2:
The patent converts the harmful effect of carbon deposition (which causes fouling) into a beneficial outcome by providing circulating particles that capture this deposited carbon. The carbon that would be harmful when depositing on reactor walls becomes valuable when deposited on circulating particles, transforming the fouling problem into a product recovery opportunity.
2Quantity of substance
If conventional pyrolysis methods are used, then carbon is formed, but the carbon particles are small and difficult to recover commercially
Solution Approach 1:
The circulating inert particles serve as carriers that collect and transport carbon particles. By depositing carbon onto these larger, pre-formed inert particles, the system produces larger aggregate particles that are easier to separate and recover commercially, rather than producing fine carbon dust that is difficult to handle.
Solution Approach 2:
The patent changes the particle size parameter of the carbon product by depositing it onto larger inert particles rather than forming it as fine particles directly. This parameter change from fine to coarse particle size dramatically improves the ease of manufacture and commercial recovery of the carbon product.
3Manufacturing precision
If fluidized bed pyrolysis is used to improve carbon deposition, then carbon is deposited on particles, but maintaining adequate solids density throughout the reactor is challenging
Solution Approach 1:
The patent implements a continuous circulation system where inert particles continuously move through the reactor, collecting carbon deposits along their path. This continuous circulation ensures that solids are maintained throughout the reactor volume, addressing the challenge of maintaining adequate solids density while enabling controlled carbon deposition.
Solution Approach 2:
The system uses dynamic particle circulation rather than static fluidized beds. The inert particles are continuously circulated through the reactor at controlled rates, allowing the system to maintain adequate solids density dynamically throughout the reactor volume while providing controlled conditions for carbon deposition.
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 system effectively reduces coke fouling and promotes the formation of larger, recoverable carbon particles, improving process stability and efficiency by maintaining a coke density above a certain threshold, thereby enhancing the commercial viability of hydrocarbon pyrolysis for hydrogen production.
Implementation Method 1
pyrolyzing a hydrocarbon-containing flow in the presence of solid particles under pyrolysis conditions in a reactor to form an H2-containing effluent and coke deposited on at least a portion of the solid particles
Implementation Method 2
the hydrocarbon-containing flow and the solid particles forming a gas-solids mixture within the reactor under forced circulation conditions
Implementation Method 3
passing the H2-containing effluent and a transfer portion of the solid particles in the gas-solids mixture upwards through the reactor into a separation vessel to produce an H2-containing product and a solids product comprising solid particles having deposited coke
Data Source
AI summary
Systems and methods are provided for forming particles containing pyrolysis coke during a forced-circulation hydrocarbon pyrolysis process. The gaseous hydrocarbon pyrolysis configuration described herein provides reduced coke fouling of the pyrolysis system. This is achieved using a forced circulation reactor design to move circulating coke through the reactor system. The gaseous hydrocarbon pyrolysis configuration is proposed to prevent the undesirable operational affects that occur in reaction zones that do not contain solid particles by maintaining an amount of solid particles above a threshold solids density in areas of the system with pyrolysis conditions. The threshold solids density is a density at which carbon formed during the pyrolysis reaction will have increased selectivity for depositing on circulating solid (coke) particles, while reducing or minimizing coke deposition on system surfaces.