Optical Concentration Monitoring With Temperature-Compensated Spectra

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Solution Overview

Problem

Existing methods for monitoring the concentration of chemical compounds in fluids, such as those used in geosciences, are limited by temperature variations, require manual analysis, and have restricted measurement ranges, leading to time-consuming and inaccurate results, especially for high concentrations.

Innovation Solution

A method using an optical measurement system and temperature sensor to construct intermediate models of absorbance vs. concentration at varying temperatures, allowing real-time monitoring without dilution, and expanding the measurement range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Beer-Lambert's law is used for concentration measurement at a given wavelength, then measurement simplicity is improved, but measurement precision deteriorates due to saturation phenomenon at high concentrations

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidconcentration measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from single-wavelength measurement to multi-wavelength spectral measurement. Instead of measuring absorbance at one wavelength, the system captures the entire absorption spectrum across multiple wavelengths, adding dimensional information that enables accurate concentration measurement even at high concentrations where single-wavelength methods fail due to saturation.

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

Solution Approach 2:

The patent changes the measurement parameter from single-wavelength absorbance to multi-wavelength spectral characteristics. By analyzing how absorbance varies across different wavelengths and using temperature-compensated spectral models, the system maintains measurement precision across a wide concentration range without suffering from saturation effects.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If temperature variations are present in the fluid, then real-world applicability is improved, but measurement precision deteriorates due to temperature dependence of absorption spectra

Engineering Contradiction:
Improvereal-world applicabilityVSAvoidconcentration measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent incorporates temperature sensing as feedback to the measurement system. The temperature sensor continuously monitors fluid temperature, and this information is used to select or adjust the appropriate spectral model for concentration calculation, compensating for temperature-induced spectral shifts and maintaining measurement accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary measurements of absorption spectra at multiple predefined temperatures during the calibration phase. These pre-acquired spectral data at different temperatures are used to build temperature-compensated models, allowing the system to predict and correct for temperature effects during actual measurements without requiring real-time temperature control.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If manual analysis with fraction collectors is used, then measurement accuracy is improved, but productivity deteriorates due to time-consuming analysis

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidanalysis speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces manual mechanical analysis methods (fraction collectors, manual sampling) with an automated optical measurement system. The system uses UV-Vis spectrometry with automated data processing to determine concentrations, eliminating the need for manual sample collection and analysis while maintaining or improving accuracy through multi-wavelength spectral analysis.

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

Solution Approach 2:

The patent enables continuous online measurement of concentration in flowing fluids, replacing discontinuous batch analysis. The optical measurement system continuously monitors the fluid stream, providing real-time concentration data without interrupting the flow or requiring sample collection, thereby dramatically increasing productivity while maintaining measurement quality.

Inventive Principle:
Principle #20Continuity of useful action

4Device complexity

If single-wavelength measurement is used, then device complexity is reduced, but adaptability deteriorates due to limited measurement range

Engineering Contradiction:
Improvesystem simplicityVSAvoidmeasurement range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a multi-functional measurement system that can handle various concentration ranges, temperatures, and fluid conditions using a single optical measurement platform. The UV-Vis spectrometer with programmable wavelength scanning and temperature compensation capabilities provides universal applicability across different measurement scenarios, replacing multiple specialized single-wavelength instruments.

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

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, real-time monitoring of chemical compound concentrations over a wide range of temperatures and concentrations, overcoming limitations of traditional methods by providing precise and dynamic measurement capabilities.

Implementation Method 1

a) by means at least of said optical measurement system and said temperature sensor, an absorbance as a function of wavelength and a temperature are measured in said measurement zone respectively for a succession of time steps

Methodology Applied
Scientific EffectAbsorbance measurement: Absorption (EM radiation)

Implementation Method 2

b) for each of said absorption spectra of said second plurality of absorption spectra, a second absorbance value is determined at the intersection between said curve and said absorption spectrum

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 3

Some are based on Beer-Lambert's law. Beer-Lambert's law is an empirical relationship that states that, at a given wavelength λ, the absorbance Aλ The absorption of a solution is proportional to the concentration c of the absorbing species

Methodology Applied
Scientific EffectBeer-Lambert's law:

Data Source

PatentEP4495581B1Method for monitoring the chemical compound concentration of a fluid in time, by means of an optical measuring system and a temperature sensor
Publication Date: 2025.12.31 IFP ENERGIES NOUVELLES
  • EP4495581B1 patent drawingFigure 1~2a
  • EP4495581B1 patent drawingFigure 2b~2c
  • EP4495581B1 patent drawingFigure 3~4a

AI summary

The invention relates to a method for determining the time evolution of the concentration of a chemical compound in a fluid, using an optical measurement system and a temperature sensor. For each predefined temperature within a plurality of predefined temperatures, an intermediate model (MTc1, MTc5) of the absorbance evolution as a function of concentration is constructed by means of linear regression and from absorption spectra measurements performed on a plurality of fluid samples at distinct concentrations of the chemical compound. From the slopes and y-intercepts of each intermediate model (MTc1, MTc5), a model of the absorbance evolution as a function of concentration and temperature is determined by linear regression.Then we determine a time evolution of a concentration of the chemical compound using the model thus determined and from a measurement of an absorption spectrum and a temperature.