Catalyst Bed Fiber Grating Layout for Accurate 3D Temperature Gradients

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Solution Overview

Problem

Current temperature measurement techniques in catalyst beds, such as thermocouples and IR cameras, fail to accurately measure 3D temperature gradients due to limitations in positioning and thermal interference, while fiber-optic sensors with fiber Bragg gratings suffer from uncertainty in sensor location and data interpretation.

Innovation Solution

A catalyst bed with a temperature sensor array comprising optical fiber parts with fixed fiber grating sensors, tensioned between mounting points, allowing precise temperature measurements along predefined locations, and incorporating additional sensors for strain correction and multi-directional gradient analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If fiber-optic sensors are loosely held in place to compensate for thermal expansion, then thermal strain is reduced, but sensor position stability deteriorates

Engineering Contradiction:
Improvesensor position stabilityVSAvoidthermal strain
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The optical fiber is divided into multiple segments, each segment being independently mounted at different heights on the reactor wall. This segmentation allows each fiber segment to independently compensate for thermal expansion at its specific location while maintaining stable positional relationships between multiple sensing points along the fiber length, resolving the contradiction between position stability and thermal strain compensation.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If thermocouples are installed inside catalyst beds for temperature measurement, then temperature monitoring capability is improved, but measurement accuracy deteriorates due to light absorption

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidlight absorption
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces traditional electrical thermocouples with optical fiber sensors that use light instead of electrical signals. The fiber-optic sensors with fiber Bragg gratings measure temperature through optical wavelength shifts, eliminating the light absorption interference that plagues electrical sensors in photo-reactor environments, thereby maintaining high measurement accuracy.

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

3Measurement precision

If multiple fiber-optic sensors are installed at different depths to map temperature gradients, then temperature profiling capability is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature gradient measurement capabilityVSAvoidsensor array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple temperature sensing functions into a single optical fiber by incorporating multiple fiber Bragg gratings at different positions along the fiber length. Each grating acts as an independent temperature sensor at a specific location, allowing simultaneous measurement of temperature gradients throughout the catalyst bed using one integrated fiber-optic sensor array rather than multiple separate sensors.

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

Enables accurate 3D temperature gradient measurement within catalyst beds by maintaining sensor position consistency and correcting for thermal strain, providing high-resolution temperature profiles with reduced measurement uncertainty.

Implementation Method 1

Each FOS is an optical fiber provided with a fiber Bragg grating (FBG). Each of the FBGs provides a local temperature sensor through its temperature-dependent optical behavior.

Methodology Applied
Scientific EffectFiber Bragg grating temperature-dependent optical behavior: Optical Fibre

Implementation Method 2

the first optical fiber part is tensioned between the mounting positions, such that each of the at least two fiber grating sensors is located at a predefined sensing position in the interior of the chamber

Methodology Applied
Scientific EffectMechanical tension: Tension

Data Source

PatentEP4671711A1Catalyst bed for measuring temperature gradients therein
Publication Date: 2025.12.31 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4671711A1 patent drawingFigure 1A
  • EP4671711A1 patent drawingFigure 1B
  • EP4671711A1 patent drawingFigure 1C

AI summary

The invention is directed at a catalyst bed comprising a temperature sensor array. The catalyst bed comprises a reactor chamber for being filled with a catalyst material, the reactor chamber having a bottom and one or more side walls defining an interior of the reactor chamber. The temperature sensor array comprises at least one first optical fiber part comprising at least two fiber grating sensors. Each of the at least two fiber grating sensors provides a temperature sensor of the temperature sensor array. The first optical fiber part is fixed to the reactor chamber in at least two mounting positions along a length of the first optical fiber part, such that the first optical fiber part between the two mounting positions extends through the interior of the chamber. The fixing of the first optical fiber part is such that the first optical fiber part is tensioned between the mounting positions, such that each of the at least two fiber grating sensors is located at a predefined sensing position in the interior of the chamber.