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EP-4474817-B1 - METHOD FOR QUANTIFYING THE GENERATION POTENTIAL OF NATURAL HYDROGEN FROM ROCK SAMPLE

EP4474817B1EP 4474817 B1EP4474817 B1EP 4474817B1EP-4474817-B1

Inventors

  • AMMOUIAL, JÉRÉMIE
  • BOUTON, Nicolas

Dates

Publication Date
20260513
Application Date
20240606

Claims (17)

  1. Method for automatically quantifying the dihydrogen generated by a sample of mineral or sedimentary parent rock containing an iron-containing metal compound, wherein a water reduction reaction is carried out in the presence of said sample and water vapor, the temperature of which is rised to approximately 1200 °C, and the amount of said dihydrogen generated by said sample during this reaction is determined in order to qualify said parent rock as a potential source of natural hydrogen.
  2. Method according to claim 1, characterized in that the water is brought into contact with the rock sample by means of an inert carrier gas carrying water vapor.
  3. Method according to either of the preceding claims, characterized in that the gaseous effluents from the water reduction reaction are separated to ensure condensation of the water and drying of the gaseous fraction of said effluents.
  4. Method according to the preceding claim, characterized in that the dried gaseous fraction is analyzed in order to determine the amount of hydrogen initially present in the sample.
  5. Method according to any one of the preceding claims, characterized in that the initial temperature of the water vapor prior to the temperature rise is between 200 °C and 400 °C.
  6. Method according to any one of the preceding claims, characterized in that the final temperature of the water vapor at the end of the temperature rise during the reduction reaction is between 600 °C and 1200 °C.
  7. Method according to any one of the preceding claims, characterized in that the gradient of the temperature increase is between 0.1 and 50 °C/min.
  8. Method according to any one of the preceding claims, characterized in that the carrier gas flow rate is between 0 and 500 mL/min.
  9. Method according to any one of the preceding claims, characterized in that the water content of the carrier gas is monitored by increasing the temperature of a water reserve or by vaporizing liquid water in a hot gas flow.
  10. Method according to any one of the preceding claims, characterized in that the temperature (TmH2) corresponding to the generation of a maximum amount of hydrogen is determined, and the kinetics of the generation of said hydrogen is deduced therefrom.
  11. Method according to any one of the preceding claims, characterized in that the quantity of hydrogen generated by the sample is used to calculate the useful molar and mass yields (η n H2 and η m H2) and to determine the potential amount of hydrogen in the parent rock, as well as the maturity of the parent rock from which said sample was taken.
  12. Device for continuously quantifying the hydrogen emitted by a sample of mineral or sedimentary parent rock, characterized in that it comprises a reactor (1) intended to receive said sample, said reactor being provided with a carrier gas injection tube (21) fed by a tank (2) containing water heated to between 0 and 100 °C and provided with a line (22) for maintaining the temperature, a reactor with a winding of heating wires ensuring temperature rises from 0 to 1200 °C inside said reactor, a separator (3) collecting the gaseous effluents from the reactor and ensuring the condensation of the water and exhaust of the gaseous fraction of the effluents to a drying means (4) and a hydrogen detector (6) analyzing the dried gaseous fraction.
  13. Device according to claim 12, characterized in that it comprises a piston (11) ensuring the introduction of the sample into the reactor (1).
  14. Device according to any one of claims 12 or 13, characterized in that it comprises thermocouples (23) intended for monitoring the temperatures of the tank (2) and the line (22) for maintaining the temperature of the injected carrier gas.
  15. Device according to any one of claims 12 to 14, characterized in that it comprises a flowmeter for monitoring the flow rate of the injected carrier gas.
  16. Device according to any one of claims 12 to 15, characterized in that it comprises an injection nozzle controlling the amount of water injected into the reactor (1).
  17. Device according to any one of claims 12 to 16, characterized in that it comprises a hygrometer or dew point detector intended for monitoring the water content of the injected carrier gas.

Description

The present invention relates to a method and device for continuous analysis of a hydrogen flow generated by chemical interaction between a water-charged carrier gas and a mineral rock sample. In general, the invention aims to determine the amount of hydrogen generated by a rock sample during a water reduction reaction at high temperature and in the presence of that sample. The invention also aims to analyze the kinetics of the reduction reaction as a function of temperature and the amount of water. Due to the decline in hydrocarbon resources and growing global energy needs, and the search for a less carbon-intensive energy mix, the production and use of hydrogen worldwide have become major issues. Besides being a raw material for the chemical industry, particularly for fertilizer production, hydrogen is also a fuel. The low greenhouse gas emissions produced by hydrogen combustion make it a good candidate as an environmentally friendly resource in the context of global warming. However, current hydrogen production remains heavily dependent on fossil fuels. Indeed, approximately 60% of the hydrogen produced comes from the high-temperature steam reforming of methane (or natural gas), itself most often generated using fossil fuels. Around 20% comes from coal gasification, and the remainder from liquid hydrocarbons. Less than 5% is produced by electrolysis, a process that is very energy-intensive, while this energy is most often generated by hydrocarbon or coal-fired power plants. The main challenge posed by hydrogen as a clean energy source, or raw material, is its production. Therefore, the exploration of natural hydrogen sources becomes crucial. Although still in the prospective stage, understanding natural hydrogen generation systems should allow us to harness this natural hydrogen in the future without resorting to fossil fuels. It is in this context that the invention provides solutions for simulating, in the laboratory, the natural conditions of hydrogen production in geological formations. The applications targeted by the invention are primarily in the field of exploring natural hydrogen sources worldwide. More specifically, the invention is mainly (but not exclusively) concerned with a particular method of generating hydrogen from mineral rocks. This method of generation results from the interaction between water, which is abundant in all deep geological environments, and the iron minerals present in certain types of rocks. This generation occurs naturally in various specific geological environments, such as mid-ocean ridges, obduction zones, subduction zones, and certain Archean and Neoproterozoic cratons. These environments are subjected to high temperatures ranging from 100°C to 400°C (and sometimes higher), thus favoring a redox reaction. Several chemical reactions can generate hydrogen naturally. The best known is the serpentinization reaction, which characterizes the hydration of olivine into serpentine. This reaction generates hydrogen as a byproduct. More precisely, water causes the oxidation of iron contained in fayalite (the iron-rich end-member of olivine, representing approximately 10% of olivine) according to the following reaction: 2H 2 O + 3Fe 2 SiO 4 = 2Fe 3 O 4 + 3SiO 2 + 2H 2 (g) A similar reaction capable of producing hydrogen also occurs during the hydration of orthopyroxene. In cratons, it is the iron-rich rocks, particularly banded iron formations (BIFs), that oxidize, with the iron changing from ferrous ( Fe²⁺ ) to ferric ( Fe³⁺ ). This same reaction can take place in the presence of amphiboles, found in granites, which are also rich in iron. US 2016039669A1 disseminates such a process for producing hydrogen. Just as in the early days of oil exploration, the first signs of hydrogen generation underground were found on the surface. Indeed, some places in the world are known for their natural hydrogen emissions, such as the Yanartas fires in Turkey, which have been burning for over 2,500 years. Other hydrogen emissions have also been detected on the surface, associated with a unique geomorphology of circular depressions measuring from a few meters to several kilometers, known as "fairy rings," and characterized by distinct vegetation. Furthermore, an onshore natural hydrogen deposit was discovered by chance and has been under development in Mali by the company Petroma (now Hydroma) since 2010. This well of The shallow depth allows for the operation of a turbine that generates electricity for a village of 1500 inhabitants. Since then, numerous exploration permits have been requested worldwide, including in the United States, France, and Australia. On the offshore side, certain geological environments have been identified as capable of generating natural hydrogen. This is the case for all mid-ocean ridges, but also for the Mariana Trench, in which several serpentinized mud volcanoes produce a gas mixing hydrogen and methane. In this context, the invention consists of a method and a