Multiphase AC Reactor Tubes for High-Temperature Heating
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Solution Overview
Problem
Existing reactors used in chemical processes, particularly for endothermic reactions, face challenges in meeting electrical, thermal, and mechanical boundary conditions, especially in single-pass pipe geometries, leading to inefficiencies and increased carbon dioxide emissions.
Innovation Solution
A reactor design that uses multi-phase alternating current to heat reaction tubes, with electrically conductive bridges connecting them, allowing for efficient electrical resistance heating and potential equalization, while preventing current flow into other process lines, thus avoiding space conflicts and enhancing cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrically conductive bridges are arranged on both sides of the power feed in single-pass pipe geometries, then electrical current is prevented from flowing into other process lines and potential equalization is achieved, but device complexity increases due to additional bridges and insulation requirements
Solution Approach 1:
The reactor is divided into electrically isolated segments using non-conductive supports positioned at regular intervals along the reaction tubes. This segmentation prevents electrical current from flowing continuously through the tubes into downstream process lines, while avoiding the need for complex bridge arrangements on both sides of the power feed.
Solution Approach 2:
The electrical isolation function is extracted from the bridge structure and implemented separately using non-conductive supports. This removes the need for complex bridge arrangements and their associated insulation requirements, simplifying the overall device structure while maintaining electrical safety.
2Ease of manufacture
If power feed arrangements are positioned close to tube inlet and outlet openings, then electrical connection is simplified, but space conflicts arise with downstream process lines and cooling performance is compromised
Solution Approach 1:
The power feed arrangements are positioned at intermediate locations along the reaction tubes rather than at the ends near inlet/outlet openings. This spatial repositioning in the longitudinal dimension resolves space conflicts with downstream process lines and allows adequate space for cooling elements, while electrical connections are maintained through the tube walls at these intermediate positions.
Solution Approach 2:
Intermediate positions along the reaction tubes serve as mediator locations for power feed arrangements. These positions are neither at the inlet nor outlet ends, allowing adequate clearance for cooling elements and process lines while still enabling effective electrical connection to the reaction tubes for heating purposes.
3Object-affected harmful factors
If conventional burners are used for heating reaction tubes, then carbon dioxide emissions increase, but alternative heating methods are ruled out due to high costs or technical limitations
Solution Approach 1:
Conventional thermal heating using combustion burners is replaced with electrical resistance heating of the reaction tubes. Electrical current is passed through the conductive reaction tubes, generating heat directly within the tubes through resistive heating, thereby eliminating the need for fossil fuel combustion and associated carbon dioxide emissions.
Solution Approach 2:
The heating method parameter is changed from chemical combustion to electrical resistance heating. This parameter change fundamentally alters the energy conversion process from chemical energy release to electrical energy conversion, achieving zero or reduced carbon dioxide emissions while providing precise temperature control for the chemical reactions.
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 reaction tubes, reduces carbon dioxide emissions, and improves the mechanical and thermal integrity of the reactor system, making it suitable for high-temperature chemical reactions like steam cracking and steam reforming.
Implementation Method 1
The reaction tubes are made of a material that allows electrical resistance heating and are electrically heated by alternating current between the electrically conductive bridges
Implementation Method 2
The electrically conductive bridges equalize the potential between the phases, so that electrical current flows from the reaction tubes via further process lines to other parts of a process plant
Data Source
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AI summary
The invention relates to a reactor for carrying out a chemical reaction, which proceeds at least partially at a temperature of at least 500°C, in a process fluid using multiphase alternating current, comprising a reactor chamber, which is surrounded by thermally insulating reactor walls, and multiple substantially straight reaction tubes; wherein the reaction tubes run through the reactor chamber between at least one tube inlet opening and at least one tube outlet opening in mutually opposing reactor walls and consist of a material which allows electrical resistance heating; wherein two electrically conductive bridges, which are spaced from each other along the reaction tubes, are provided in the reactor chamber and connect the reaction tubes electrically conductively to each other; wherein electrically conductive current feed-in assemblies are provided, which extend through one or more feed-in openings in one of the reactor walls, wherein each reaction tube is connected in an electrically conductive manner to one of the current feed-in assemblies, wherein each current feed-in assembly is connected electrically conductively to one of the reaction tubes between the bridges and is or can be connected to one of the phases of the alternating current.