Vertical Thermosiphon Cooling for CO2 Methanation Reactors

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Solution Overview

Problem

Current cooling systems for methanation reactors, particularly those using phase change cooling, face issues such as stratification between liquid and vapor phases, leading to inefficient cooling and premature catalyst deactivation, and require additional pumps increasing costs without ensuring optimal operation.

Innovation Solution

A cooling device utilizing vertically oriented tubes with a thermosiphon mechanism for continuous water and steam circulation, regulated by a control loop that adjusts pressure based on actual bed temperature to maintain optimal conversion efficiency, preventing stratification and reducing construction and operational costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If coils or bundles are used for phase change cooling, then cooling effect is improved, but stratification between liquid and vapor phases occurs leading to inefficient cooling

Engineering Contradiction:
Improvecooling effectVSAvoidphase distribution uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent inverts the conventional horizontal or slightly inclined coil configuration by using vertically oriented tubes. This inversion eliminates stratification between liquid and vapor phases, ensuring efficient phase change cooling throughout the entire reactor volume without dead zones.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from horizontal/2D coil arrangements to vertical/3D tube configurations. This dimensional change allows gravity to naturally separate phases vertically while maintaining uniform cooling distribution throughout the reactor, preventing stratification issues.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If circulation pumps are inserted in the cooling device, then cooling system reliability is improved, but investment and operating costs increase

Engineering Contradiction:
Improvecooling system operationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs natural circulation driven by density differences between liquid and vapor phases. The vertical tube configuration allows the cooling system to self-regulate without external pumps, eliminating mechanical complexity while maintaining reliable operation through buoyancy-driven flow.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical circulation pump system with a thermally-driven natural circulation system. The phase change and density variations automatically drive the cooling fluid circulation, substituting mechanical complexity with thermal physics-based operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If tubular exchanger configuration is used, then temperature control is improved, but construction cost of shell increases sharply at high pressures

Engineering Contradiction:
Improvetemperature controlVSAvoidconstruction cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent merges the cooling function directly into the reactor structure by making the reactor walls themselves the heat exchange surface. This eliminates the need for separate high-pressure shells and internal tubular exchangers, reducing construction complexity and cost while maintaining effective temperature control.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the reactor walls multi-functional by combining structural containment and heat exchange functions. The same vertical tubes that form the reactor boundary also serve as the cooling heat exchange surface, eliminating redundant components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If fixed bed reactors without internal cooling system are used, then design simplicity is improved, but temperature increase leads to drop in conversion efficiency

Engineering Contradiction:
Improvedesign simplicityVSAvoidconversion efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent combines the cooling function with the reactor structure itself rather than adding separate cooling systems. The vertical tube walls perform both structural and heat exchange functions, maintaining design simplicity while enabling effective temperature control to preserve conversion efficiency.

Inventive Principle:
Principle #5Merging (Combining)

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 solution ensures efficient and uniform temperature control within the reactor, maintaining catalyst activity and optimizing conversion rates while avoiding the need for auxiliary pumps, thus reducing costs and preventing toxic compound formation.

Implementation Method 1

A cooling device utilizing vertically oriented tubes with a thermosiphon mechanism for continuous water and steam circulation

Methodology Applied
Scientific EffectThermosiphon: Thermosyphon

Implementation Method 2

These systems are based on the use of coils into which the cooling water is introduced and the phase change takes place in the coils

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3389844B1Cooling device for carbon dioxide methanation catalytic reactor
Publication Date: 2021.01.27 GDF SUEZ SA
  • EP3389844B1 patent drawingFigure 1
  • EP3389844B1 patent drawingFigure 2~3

AI summary

The cooling device (10) for a carbon dioxide methanation catalytic reactor (105) comprises: - at least one cooling tube (110) passing through the reactor comprising: - an inlet (115) and - an outlet (120) positioned at an altitude higher than the inlet, - a water tank (125) supplying the tube by gravity, comprising: - a water outlet (130), connected to the inlet of the tube; - a water and steam inlet (135) connected to the outlet of the tube; - a steam outlet (140) and - a water supply inlet (145), - a means (150) for measuring the temperature in the catalytic reactor and - a means (155) for controlling a water level in the water tank configured to supply the water tank with water in order to maintain a predefined water level in the tank.