Segmented Pyrolysis Reactors for Uniform Heating and Particle Flow
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Solution Overview
Problem
Existing pyrolytic decomposition processes face challenges in achieving homogeneous heat input and preventing bridging/blocking issues while maintaining efficient energy transfer and economic viability, particularly in the thermal decomposition of hydrocarbons like methane.
Innovation Solution
A device comprising at least two reactors connected in series, with spaced electrodes for resistance heating and a mechanism to transfer particulate material between reactors, ensuring homogeneous heat distribution and preventing blocking, while allowing for the production of hydrogen and carbon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrical resistance heating is used in a single reactor with carbon particles, then the pyrolysis reaction can proceed at high temperature, but homogeneous heat input becomes difficult to maintain over extended periods due to varying electrical resistance
Solution Approach 1:
The single reactor is divided into multiple reactors connected in series, with heating zones distributed across different reactors. This segmentation allows each reactor to maintain more stable and homogeneous electrical resistance conditions, preventing the formation of hot spots while ensuring consistent high-temperature pyrolysis throughout the system.
2Productivity
If carbon particles are continuously added and removed from a single reactor, then the process can operate continuously, but bridging and blocking issues increase
Solution Approach 1:
The continuous process is segmented into multiple reactors in series, allowing carbon particles to flow sequentially through each reactor. This distribution reduces particle accumulation and minimizes bridging and blocking issues in any single reactor while maintaining continuous operation.
Solution Approach 2:
Inter-reactor transfer devices serve as intermediaries between reactors, controlling particle flow and preventing direct contact that could lead to bridging. These transfer mechanisms regulate the movement of carbon particles, ensuring smooth flow and reducing blocking tendencies.
3Ease of operation
If the electrical resistance of the particle bed varies, then current flows preferentially in areas of lower resistance, but this creates hot spots and ultimately fails the heating concept
Solution Approach 1:
By distributing the heating function across multiple reactors, each with its own electrode system, the electrical load and heat generation are divided. This prevents localized overheating in any single reactor while maintaining overall efficient current flow through the particle beds.
Solution Approach 2:
Each reactor can be independently controlled with tailored electrical parameters, allowing optimization of heat distribution in each local zone. This localized control ensures uniform temperature profiles and prevents hot spot formation while maintaining ease of operation.
4Quantity of substance
If conventional steam reforming is used for hydrogen production, then hydrogen can be produced from hydrocarbons, but CO2 emissions reach up to 0.4 m3 per m3 of hydrogen
Solution Approach 1:
The process uses pyrolysis in an inert or reducing atmosphere to decompose hydrocarbons into hydrogen and carbon without oxidation reactions. This eliminates CO2 emissions associated with steam reforming while maintaining high hydrogen production efficiency.
Solution Approach 2:
The process changes the fundamental reaction parameters from oxidative (steam reforming) to thermal decomposition (pyrolysis). By operating at high temperatures without oxygen or water vapor involvement, the process produces hydrogen cleanly while the carbon byproduct can be utilized or sequestered.
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 solution enables efficient pyrolytic decomposition of hydrocarbons with uniform heat distribution, reducing the risk of hot spots and bridging, and optimizing energy use, thereby enhancing the process's economic viability and product yield.
Implementation Method 1
The reactor is resistance-heated via at least one pair of electrodes arranged axially in the particle bed. Although carbon particles themselves have high electrical conductivity, the electrical resistance results from the contact points between the particles and the small transfer surfaces. The electrical current flows through the carbon bed and dissipates into thermal energy due to the electrical resistance of the particle bed.
Implementation Method 2
Non-oxidative processes involve the thermal decomposition (or dissociation, pyrolysis, cracking) of hydrocarbons into hydrogen and carbon. The thermal decomposition of natural gas has been used for several decades as a means of producing carbon black, with hydrogen being an additional valuable product in the process. In these processes, hydrocarbon vapor is decomposed into hydrogen and soot particles at a temperature of approximately 1400°C over a preheated contact.
Data Source
Figure 1A~1B
Figure 2
AI summary
The present invention relates to a device for the pyrolytic conversion of hydrocarbons to hydrogen and carbon, comprising at least two reactors connected in series with a reactor chamber, wherein each of these reactor chambers has at least two electrodes spaced apart from one another in the direction of flow of the hydrocarbons, via which the reactor can be heated by resistance, and wherein each upstream reactor has in its lower region a removal device for particulate material which is connected to the upper region of the respective downstream reactor and enables the supply of particulate material to the upper region of the respective downstream reactor.