Soil Carbon Quantification via Multi-Stage Thermal Analysis

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Solution Overview

Problem

Current methods for characterizing carbon forms in soils, adapted from petroleum industry techniques, face challenges in differentiating between organic and mineral carbon, leading to inaccurate measurements and inefficient analysis, particularly due to the thermal decomposition of organic and mineral components at similar temperatures.

Innovation Solution

A method involving a heating sequence with multiple isothermal stages under inert and oxidizing atmospheres, allowing for continuous measurement of hydrocarbon compounds, CO, and CO2, and using a parameter SCmin to differentiate between organic and mineral carbon content, with specific formulas for TOCfs and MinCfs parameters to accurately quantify carbon forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional thermal analysis methods are used to measure carbon in soils, then the analysis can be performed using standard equipment, but the method cannot accurately differentiate between organic and mineral carbon forms

Engineering Contradiction:
Improvecarbon form differentiation accuracyVSAvoidmeasurement accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the carbon analysis into distinct temperature zones: a first heating sequence (200-400°C) that primarily releases CO2 from organic carbon, and a second heating sequence (400-850°C) that releases CO2 from mineral carbon. This segmentation allows differentiation between organic and mineral carbon forms by measuring CO2 evolution in separate temperature intervals, resolving the contradiction between measurement precision and reliability.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple extraction and separation methods are used to characterize different carbon forms, then accurate characterization can be achieved, but the analysis time and complexity increase significantly

Engineering Contradiction:
Improvecarbon form characterization accuracyVSAvoidanalysis time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges multiple extraction and separation methods into a single thermal analysis procedure. By combining the measurement of CO2 evolution from organic carbon (first heating sequence) and mineral carbon (second heating sequence) into one continuous experiment, the method achieves accurate carbon form characterization without the time loss associated with multiple separate analyses.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thermal analysis method serves multiple functions simultaneously: it quantifies total organic carbon, quantifies mineral carbon, and characterizes carbon forms all in a single measurement sequence. This multi-functionality eliminates the need for separate extraction and analysis steps, significantly reducing analysis time while maintaining precision.

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

3Reliability

If specialized service providers are used for soil carbon analysis, then environmental and safety constraints are met, but the analysis costs and time increase

Engineering Contradiction:
Improveenvironmental and safety complianceVSAvoidanalysis efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent enables laboratories to perform soil carbon analysis in-house using standard thermal analysis equipment rather than relying on specialized service providers. The method incorporates environmental and safety considerations directly into the measurement protocol, allowing institutions to maintain compliance while improving analysis efficiency and reducing costs through self-service capability.

Inventive Principle:
Principle #25Self-service

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 enables precise characterization and quantification of organic and mineral carbon, improving the discrimination between carbon forms and providing reliable, reproducible results, overcoming the limitations of existing methods by accurately determining carbon content in soils.

Implementation Method 1

The sample is heated according to a first heating sequence under an inert atmosphere, and a quantity of hydrocarbon compounds, a quantity of CO and a quantity of CO2 released during said first heating sequence are continuously measured

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

a residue of said sample from said first heating sequence is heated according to a second heating sequence under an oxidizing atmosphere, and a quantity of CO and a quantity of CO2 released during said second heating sequence is measured

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4314807B1Method for the quantification and characterization of carbon in soils
Publication Date: 2025.01.22 IFP ENERGIES NOUVELLES
  • EP4314807B1 patent drawingFigure 1~2A
  • EP4314807B1 patent drawingFigure 2B~2C
  • EP4314807B1 patent drawingFigure 2D~3A

AI summary

The invention relates to a method for characterizing and quantifying carbon of a surface deposit, in which: heat is applied to a sample of the deposit in an inert atmosphere, comprising at least six isothermal steps interconnected by a thermal gradient; heat is applied to the sample residue in an oxidizing atmosphere; and the quantities of HC, CO and CO 2 released during these heating steps are measured. The ratio of mineral carbon to total carbon in the sample is determined, and the content of organic carbon and/or mineral carbon in the sample is then determined as a function of the ratio: (i) taking account of an estimated quantity of CO 2 released by thermal cracking of the organic material of the sample during the heating in an inert atmosphere if the ratio is substantially non-zero; (ii) if the ratio is substantially zero, the mineral carbon content is zero.