Induction Heating of Ferromagnetic Reactors Above the Curie Point

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Solution Overview

Problem

Existing induction heating methods for reactors are inefficient, particularly when using ferromagnetic materials, as they require high energy input to maintain desired temperatures below the Curie temperature, limiting the efficiency of processes like the reverse water gas shift reaction.

Innovation Solution

Heating elements made of ferromagnetic materials are operated above their Curie temperature, allowing for a sudden increase in temperature with lower power input, and maintaining this temperature by adjusting power input accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ferromagnetic heating elements are operated below the Curie temperature using conventional induction heating, then the reactor can be heated, but high energy input is required to maintain desired temperatures

Engineering Contradiction:
Improvereactor temperatureVSAvoidpower consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by transitioning the ferromagnetic heating elements from below to above the Curie temperature. This fundamental parameter change alters the magnetic properties of the material, eliminating magnetic hysteresis losses and enabling more efficient induction heating. The system operates in a temperature regime where the material's magnetic permeability changes dramatically, reducing energy consumption while maintaining or increasing heating effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention exploits the phase transition that occurs at the Curie temperature point. By deliberately operating above this critical temperature threshold, the system takes advantage of the phase change from ferromagnetic to paramagnetic state. This phase transition is the core mechanism that enables reduced power consumption, as the material no longer exhibits magnetic hysteresis that would otherwise consume additional energy during cyclic heating operations.

Inventive Principle:
Principle #36Phase transitions

2Power

If high power input is used to maintain temperature below Curie temperature, then desired reactor temperature is achieved, but heating efficiency is limited

Engineering Contradiction:
Improveheating powerVSAvoidenergy efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent resolves this contradiction by changing the operating temperature parameter to exceed the Curie temperature. This parameter change fundamentally alters the energy loss characteristics of the ferromagnetic material. Above the Curie temperature, the material transitions to a paramagnetic state where magnetic hysteresis losses are eliminated, thereby significantly improving energy efficiency while maintaining the necessary heating power for reactor operation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts what was traditionally considered a harmful limitation (the Curie temperature threshold that was believed to mark the end of effective induction heating) into a beneficial operating regime. By operating above rather than below the Curie temperature, the system transforms the previously problematic magnetic phase transition into an advantage, eliminating energy-wasting hysteresis effects and achieving superior heating efficiency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Temperature

If the reactor temperature is increased above the Curie temperature of heating elements, then a sudden increase in temperature is achieved with lower power input, but temperature control becomes more challenging

Engineering Contradiction:
Improveheating element temperatureVSAvoidtemperature control
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent addresses temperature control challenges by implementing feedback mechanisms that monitor the temperature of heating elements and adjust the induction heating power accordingly. This feedback control system compensates for the non-linear temperature-power relationship that occurs when operating above the Curie temperature, allowing the system to maintain precise temperature control despite the dramatic changes in material properties at the phase transition point.

Inventive Principle:
Principle #23Feedback

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 approach enhances induction heating efficiency by maintaining higher temperatures with lower power consumption, improving processes such as the reverse water gas shift reaction by increasing CO2 conversion.

Implementation Method 1

Induction heating (or induction heating) is also a process of generating heat in an electrically conductive materials by passing an induced electric current (or secondary current) through the material (i.e. eddy energy losses). However, induction heating is different from resistive heating in that the current is generated by a rapidly alternating magnetic field penetrating the material (electromagnetic induction).

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Induction heating may additionally occur by hysteresis effects induced in the electrically conductive elements. Hysteresis occurs in ferromagnetic materials below their Curie temperature.

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Implementation Method 3

The heat is then transferred to the relevant material via thermal conduction.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4648551A1Efficient induction heating of a reactor
Publication Date: 2025.11.12 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4648551A1 patent drawingFigure 1A~1B
  • EP4648551A1 patent drawingFigure 2A~2B
  • EP4648551A1 patent drawingFigure 3A~3B

AI summary

The invention is in the field of inductive heating of reactors and concerns a method for for induction heating of a reactor wherein the reactor comprises one or more heating elements made of a ferromagnetic material and the heating elements are heated above the Curie temperature of the ferromagnetic material. The invention furthermore concerns a method for carrying out an endothermic reaction in a reactor and a method for desorbing an adsorbate from a sorbent in a reactor making use of the method for induction heating.