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US-12618012-B2 - Method for producing hydrocarbon

US12618012B2US 12618012 B2US12618012 B2US 12618012B2US-12618012-B2

Abstract

CO 2 introduced into the ground reacts with water in the moisture present in the surroundings to convert to hydrocarbon, suppressing leakage of CO 2 above ground. The method for producing hydrocarbon has an introduction step for introducing CO 2 into a storage site in the ground where moisture and a catalytic metal are present, the pressure is 5 MPa or higher, and the temperature is 40° C. or higher, to bring the CO 2 into a subcritical state or a supercritical state, and a synthesis step for reacting the water in the moisture with the subcritical or supercritical CO 2 in the storage site to synthesize hydrocarbon. The storage site is preferably a site from 800 m to 1200 m below ground. The pressure of the storage site is preferably 8 MPa or higher.

Inventors

  • Takashi Fujii
  • Masateru Nishioka

Assignees

  • NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY

Dates

Publication Date
20260505
Application Date
20210917
Priority Date
20201014

Claims (6)

  1. 1 . A method for producing a hydrocarbon comprising: introducing catalytic particles comprising a catalytic metal and CO 2 into an underground storage site where moisture is present, the pressure is 5 MPa or higher, and the temperature is 40° C. or higher, thereby bringing CO 2 into a subcritical or supercritical state; and reacting water in the moisture and CO 2 in the subcritical or supercritical state at the storage site to synthesize the hydrocarbon.
  2. 2 . The method for producing a hydrocarbon according to claim 1 , wherein the catalytic particles comprises a core which is a nanoparticle support, and a shell which is the catalytic metal.
  3. 3 . The method for producing a hydrocarbon according to claim 1 , wherein the catalytic metal is a metal that allows the Fischer-Tropsch reaction to proceed.
  4. 4 . The method for producing a hydrocarbon according to claim 1 , wherein the storage site is at a point between 800 m and 1,200 m below the ground surface.
  5. 5 . The method for producing a hydrocarbon according to claim 1 , wherein the catalytic metal is one or more of Ni, Fe, Co, and Pd.
  6. 6 . The method for producing a hydrocarbon according to claim 1 , wherein the pressure at the storage site is 8 MPa or higher.

Description

TECHNICAL FIELD The present application relates to a method in which CO2 stored in the ground is converted to a solid or liquid hydrocarbon, thereby reducing CO2 above ground and obtaining a valuable resource. BACKGROUND ART A system for storing and sequestrating CO2 is known in which CO2 is dissolved in a solvent and injected into an underground aquifer by pressure (Patent literature 1). According to the system in Patent literature 1, CO2-dissolved water can be stored in the ground at a concentration close to the saturation concentration. However, if CO2-dissolved water is stored underground for a long period of time, there is a risk of CO2 leaking to the ground surface. The emergence of a technology to suppress the leakage of CO2 stored underground to the ground surface has been desired. PRIOR ART LITERATURE Patent Literature Patent literature 1: JP 2010-201330 A SUMMARY OF INVENTION Problem to be Solved by the Invention The objective of the present application is to provide a method for suppressing CO2 leakage to the ground surface by synthesizing a hydrocarbon from water and CO2 underground. Means for Solving the Problem A method for producing a hydrocarbon in one aspect of the present application comprises: an introduction step in which CO2 is brought into a subcritical or supercritical state by introducing CO2 into an underground storage site where moisture and a catalytic metal are present, the pressure is 5 MPa or higher, and the temperature is 40° C. or higher; and a synthesis step in which water in the moisture and CO2 in the subcritical or supercritical state are allowed to react at the storage site to synthesize the hydrocarbon. A method for producing a hydrocarbon in another aspect of this application comprises: an introduction step in which CO2 is brought into a subcritical or supercritical state by introducing catalytic particles comprising a catalytic metal and CO2 into an underground storage site where moisture is present, the pressure is 5 MPa or higher, and the temperature is 40° C. or higher; and a synthesis step in which water in the moisture and CO2 in the supercritical state are allowed to react at the storage site to synthesize the hydrocarbon. Effects of Invention According to the present application, CO2 introduced into the ground reacts with water present in the surrounding moisture to produces a hydrocarbon, and therefore CO2 is less likely to leak to the ground surface. In addition, according to the present application, the hydrocarbon produced underground can be extracted and used as a valuable resource. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 A schematic diagram of a reactor and a collection unit used in Examples. FIG. 2 A FT-IR spectrum of adherent matter on the filter from Example 1. FIG. 3 A GC-MS chromatogram of residue in the reaction vessel from Example 1. FIG. 4 A GC-MS chromatogram of adherent matter on the filter from Example 1. FIG. 5 A GC-MS chromatogram of a deuterated chloroform solution in the first trap of the collection unit from Example 1. FIG. 6 A GC-MS chromatogram of adherent matter in the last trap of the collection unit from Example 1. FIG. 7 A GC-MS chromatogram of gas in the gas sampling bag from Example 1. FIG. 8 GC-MS chromatograms of products at various sites of the reactor and collection unit from Example 1. MODE FOR CARRYING OUT THE INVENTION A method for producing a hydrocarbon according to an embodiment of the present application comprises an introduction step and a synthesis step. In the introduction step, CO2 is brought into a subcritical or supercritical state by introducing CO2 into an underground storage site where moisture and a catalytic metal are present, the pressure is 5 MPa or higher, and the temperature is 40° C. or higher. In other words, in the introduction step, CO2 is introduced into an underground storage site where water and a catalytic metal are present and CO2 becomes subcritical or supercritical. CO2 can be introduced, for example, by connecting the ground surface and the storage site with a pipe, which can be used to inject CO2 by pressure. This storage site may be, for example, a cleavage, fissure, or pore in a soil or rock formation. Moisture may be rainwater or surface water that has percolated from the ground surface into the subsurface and been stored in cleavages, fissures, or pores in the soil or rock formations, or it may be water of crystallization, such as the water component of a metal salt hydrate present in the ground. Catalytic metals are present as mineral compositions in soil or rock formations, or are attached to cleavages, fissures, or pores in soil or rock formations. From the perspective of storing CO2 at the storage site, CO2 introduced into the ground is preferably a gas or liquid. The storage site where CO2 becomes subcritical or supercritical is, for example, at a temperature of 40° C. or higher and a pressure of 8 MPa or higher. In Japan, moisture is generally present and metals that can serve as cataly