CN-122006756-A - Composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas and application method thereof

CN122006756ACN 122006756 ACN122006756 ACN 122006756ACN-122006756-A

Abstract

The invention discloses a composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas and an application method thereof, and belongs to the technical field of catalyst materials. The composite catalyst consists of a metal matrix, a catalytic induction phase and an interface regulation phase. The catalysis induction phase is a reversible valence state metal compound, and the interface regulation phase is selected from at least one of metal halogen salt or metal carbonate. Heating a metal matrix to be molten in an inert atmosphere, adding a catalytic induction phase, uniformly dispersing, adding an interface regulation phase, uniformly mixing, and cooling to obtain the composite catalyst. The application method comprises the steps of arranging a high-temperature resistant sealed reaction section at a target production layer position of a shaft, filling a composite catalyst in the reaction section, heating to enable the composite catalyst to be converted into a molten state, and then guiding the carbon-rich natural gas into the reaction section to enable the carbon-rich natural gas to be fully contacted with the molten state catalyst to generate a cracking reaction. The composite catalyst of the invention solves the problems of easy deactivation, uncontrollable carbon structure, multiple side reactions and the like of the traditional catalyst.

Inventors

ZHOU YING
WANG KUN
ZHANG RUIYANG
GUO HENG
LI RENZE
YU PAN

Assignees

西南石油大学

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (9)

1. The composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas is characterized by comprising a metal matrix, a catalytic induction phase and an interface regulation phase, wherein the metal matrix comprises at least two metals with melting points lower than 400 ℃, the catalytic induction phase is a reversible valence metal compound, and the interface regulation phase is selected from at least one of metal halogen salt or metal carbonate.
2. The composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas according to claim 1, wherein the metal matrix is heated to be completely melted in an inert atmosphere to form a molten metal matrix, then a catalytic induction phase is added to uniformly disperse the metal matrix in the molten metal matrix, and then an interface control phase is added to uniformly mix and cool the mixture to obtain the target composite catalyst.
3. The composite catalyst for the production of graphite-like carbon by cracking carbon-rich natural gas according to claim 2, wherein the catalytically induced phase is selected from at least one of oxides or sulfides of iron, cerium, tungsten, cobalt or molybdenum.
4. The composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas according to claim 3, wherein the catalytic induction phase is a binary composite of CeO 2 and MoO 3 , or a binary composite of CeO 2 and WO 3 , or a ternary composite of CeO 2 、MoO 3 and WO 3 , and the addition amount is 0.5-10% of the total mass of the catalyst.
5. The composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas according to claim 2, wherein the interface regulating phase is at least one selected from NaCl, KCl, laCl 3 、MgCl 2 、Li 2 CO 3 、Na 2 CO 3 , and the addition amount is 0.1-5wt% of the total mass of the catalyst.
6. The composite catalyst for the production of graphite-like carbon by cracking carbon-rich natural gas according to claim 2, wherein the metal matrix is selected from at least two of Sn, bi, ga, in, pb.
7. An application method of the composite catalyst as claimed in any one of claims 1 to 6, wherein the composite catalyst is placed in a shaft, and in-situ cracking of carbon-rich natural gas in the shaft is realized at 400-950 ℃ to prepare hydrogen and graphite-like carbon.
8. The method for using the composite catalyst according to claim 7, comprising the steps of: (1) Arranging a high-temperature-resistant sealed reaction section at a target zone position of an oil-gas well shaft, and filling a composite catalyst into the reaction section; (2) Heating and raising the temperature by using the formation temperature, the auxiliary heating of a shaft or the superposition of the formation temperature and the auxiliary heating of the shaft so as to enable the composite catalyst to be converted into a molten state to form a continuous liquid reaction environment; (3) And (3) introducing the carbon-rich natural gas extracted from the shaft into a reaction section, fully contacting the carbon-rich natural gas with a molten catalyst, controlling the reaction temperature to be 400-950 ℃, and cracking methane and carbon dioxide in the natural gas to generate hydrogen and graphite-like carbon, wherein the graphite-like carbon is deposited or enriched in the shaft reaction section in situ.
9. The method of using the composite catalyst according to claim 8, wherein step (3) uses the natural potential difference formed between the wellbore casing and the formation during the cracking process, or additionally applies a dc bias, to build up a micro-electrochemical reaction environment in the molten catalyst.

Description

Composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas and application method thereof Technical Field The invention relates to the technical field of catalyst materials, in particular to a composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas and an application method thereof. Background Along with the large-scale development of unconventional and deep oil and gas resources, the wellbore environment increasingly presents complex characteristics of high temperature, high pressure, rich carbon, high sulfur and the like, the traditional ground centralized treatment mode is limited and obvious in energy efficiency, cost and safety, and development of in-situ conversion and resource utilization technologies suitable for the extreme environment of the wellbore is needed. The direct cracking of carbon-rich natural gas into hydrogen and carbon materials in a well bore can reduce the ground treatment load and realize the efficient on-site utilization of resources, thus attracting attention. The technology aims to realize the efficient separation and cooperative utilization of hydrocarbon resources, hydrogen can be used as clean energy or to drive underground equipment, and solid carbon can be deposited, sealed or utilized in situ. The graphite-like carbon has the characteristics of ordered lamellar structure and defects, has good conductivity, temperature resistance, corrosion resistance and stability, and has remarkable value in the fields of energy storage, composite materials and the like. The graphite-like carbon is directionally prepared under the in-situ condition of the shaft, and has important significance for improving the economical efficiency and the added value of the products in the cracking process. The existing cracking carbon production technology mostly adopts transition metal solid catalysts such as Ni, fe, co and the like, and the traditional catalysts are easy to sinter and carbon deposit to cover active sites under high temperature and high pressure, so that the deactivation is caused, and the long-term stable operation is difficult. In addition, the traditional catalytic system has limited capability of regulating and controlling a carbon structure, most products are disordered carbon such as carbon black, fiber carbon and the like, the structure and the morphology of the prepared graphite-like carbon are difficult to effectively control, the added value of the products is limited, and the products are easy to poison and have insufficient adaptability in a sulfur-containing and strong-reducibility shaft environment. The catalytic cracking technology of the molten metal is gradually rising in recent years, and the problems of sintering and carbon deposition inactivation of the traditional catalyst can be relieved by using liquid metal or alloy as a reaction medium, and the catalytic cracking technology has good heat transfer and self-updating characteristics and is more suitable for the high-temperature and high-heat-flow environment of a shaft. However, the existing melting system has single multi-focus or binary alloy and relatively single function, mainly focuses on hydrogen production rate, has insufficient regulation and control research on carbon material structure and has a plurality of organic byproducts, and the controllable preparation of graphite-like carbon is difficult to realize. Meanwhile, a single system is difficult to combine cracking activity, sulfur toxicity resistance and carbon structure induction capability, and the problems of insufficient selectivity, uncontrollable product structure and the like still exist in the atmosphere of a complex shaft. In addition, the traditional molten metal methane cracking catalyst is easy to have the problems of catalyst oxidation deactivation, carbon product oxidation, more organic matters generated by side reaction and the like after introducing carbon dioxide. Therefore, there is a need to develop a catalytic system that can realize heterogeneous synergy, multi-active center coupling, controllable preparation of graphite-like carbon by carbon structure induced growth in a molten state, and can catalyze the cracking of carbon dioxide. Disclosure of Invention Aiming at the problems that the graphite-like carbon can not be controllably prepared by the catalyst used in the existing carbon-rich natural gas cracking technology and the catalyst is easy to be inactivated, the invention provides a composite catalyst for preparing the graphite-like carbon by cracking the carbon-rich natural gas. The catalyst is suitable for preparing graphite-like carbon materials by in-situ cracking of natural gas in a high-temperature environment of a shaft. The invention provides a composite catalyst for preparing graphite-like carbon by cracking carbon-rich natural gas, which is a heterogeneous synergistic catalyst formed by taking a low-melting-point metal matrix as a continuous phase, a