Multiphase AC Reaction Tube Reactor for Low-CO2 High-Temperature Heating
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Solution Overview
Problem
Existing reactors used in chemical processes, such as steam cracking and steam reforming, face challenges in meeting electrical, thermal, and mechanical boundary conditions, particularly for single-pass tube geometries, leading to inefficiencies and high carbon dioxide emissions when using fired reactors.
Innovation Solution
A reactor design featuring a reactor chamber with thermally insulating walls and multiple straight reaction tubes made of heat-resistant materials, connected by electrically conductive bridges that allow for multiphase alternating current heating, ensuring efficient electrical resistance heating and minimizing carbon dioxide emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fired reactors with burners are used for heating reaction tubes, then high temperature for chemical reactions is achieved, but carbon dioxide emissions increase and energy efficiency decreases
Solution Approach 1:
The patent replaces the mechanical combustion system (burners firing fossil fuels) with an electrical resistance heating system. Electrically conductive bridges made of materials like graphite or metal alloys are positioned to contact the reaction tubes, allowing direct electrical current flow through the tubes to generate heat via Joule heating. This substitution eliminates the need for combustion, thereby eliminating carbon dioxide emissions while maintaining the required high temperatures for endothermic reactions.
Solution Approach 2:
The patent changes the heating mechanism from thermal energy transfer via combustion to direct electrical energy conversion. By introducing electrically conductive bridges and applying electrical current, the system transforms the energy input parameter from chemical combustion to electrical resistance heating, achieving the same thermal effect without the harmful byproducts of fossil fuel burning.
2Object-generated harmful factors
If electrical resistance heating is applied to single-pass tube geometries, then carbon dioxide emissions are reduced, but electrical and thermal boundary conditions cannot be met with known arrangements
Solution Approach 1:
The patent introduces electrically conductive bridges as intermediary components between the power supply and the reaction tubes. These bridges, made of materials with high electrical conductivity such as graphite blocks or metal alloys, serve as mediators that efficiently transfer electrical current to the reaction tubes. The bridges are positioned to make direct contact with the tubes, ensuring reliable electrical connection while allowing the tubes to maintain their single-pass geometry without requiring complex winding or U-bend configurations.
Solution Approach 2:
The heating system is segmented into multiple independent electrically conductive bridges that can be positioned at different locations along the reaction tubes. This segmentation allows flexible adaptation to various tube geometries and lengths, ensuring that electrical and thermal boundary conditions are met throughout the entire reactor chamber without requiring changes to the fundamental single-pass tube design.
3Use of energy by moving object
If reaction tubes are made electrically conductive for resistance heating, then electrical heating efficiency improves, but material selection becomes more restricted
Solution Approach 1:
The patent employs composite material structures where the reaction tubes are made of electrically conductive materials such as graphite, graphite alloys, or metal alloys with sufficient electrical conductivity. These materials are selected to provide both the required mechanical strength and thermal resistance for high-temperature operation and adequate electrical conductivity for efficient resistance heating. The use of composite or alloy materials allows simultaneous satisfaction of mechanical, thermal, and electrical requirements.
Solution Approach 2:
The patent changes the material parameter selection criteria by prioritizing materials with higher electrical conductivity while maintaining high-temperature stability. Materials such as graphite and its alloys, which naturally possess both high-temperature resistance and good electrical conductivity, are selected. This parameter change in material selection allows the tubes to serve dual functions: structural containment and electrical heating element, thereby improving heating efficiency without significantly restricting material options.
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 design enables efficient heating of process fluids to temperatures above 500°C, reducing carbon dioxide emissions and meeting electrical, thermal, and mechanical boundary conditions, while allowing for cost-effective and efficient operation of chemical reactions like steam cracking and steam reforming.
Implementation Method 1
The reaction tubes... consist of a material that permits electrical resistance heating
Data Source
AI summary
A reactor for carrying out a chemical reaction using multiphase alternating current, includes a reactor chamber surrounded by thermally insulating reactor walls and multiple substantially straight reaction tubes. The reaction tubes run between at least one tube inlet opening and at least one tube outlet opening in opposite reactor walls and consist of a material that permits electrical resistance heating. Two electrically conductive bridges spaced apart along the reaction tubes are provided, each of which electrically conductively connects the reaction tubes to one another. Electrically conductive power input arrangements are provided extending through one or more input openings in one of the reactor walls. Each reaction tube is electrically conductively connected to one of the power input arrangements. Each power input arrangement is electrically conductively connected between the bridges to one of the reaction tubes and is connected or connectable to one of the phases of the alternating current.