CN-122006767-A - Methane oxidative coupling catalyst and preparation method and application thereof

CN122006767ACN 122006767 ACN122006767 ACN 122006767ACN-122006767-A

Abstract

The invention discloses a methane oxidative coupling catalyst and a preparation method and application thereof. The methane oxidative coupling catalyst is obtained by roasting a mixed material comprising a nano catalyst intermediate state and a flocculating agent in a protective atmosphere, and the methane oxidative coupling catalyst contains sodium element. According to the invention, a high molecular flocculant is adopted to perform rapid solid-liquid separation on the intermediate state of the low-temperature OCM nano catalyst, and as a result, the catalyst prepared by the separation method disclosed by the invention is found to be further improved in CO yield while keeping higher reaction activity in the methane oxidative coupling reaction under the condition of not changing the composition of active components of the catalyst. Therefore, the method for quickly separating the methane oxidative coupling catalyst can reduce the preparation cost of the catalyst and improve the preparation efficiency of the catalyst.

Inventors

WANG XUE
WU JIEHUA
DING CHENGZHE
LI WEI
BAI JIE
LIU DONGBING

Assignees

中国石油化工股份有限公司
中石化(北京)化工研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20241122
Priority Date: 20241111

Claims (10)

1. A methane oxidative coupling catalyst, which is characterized in that: the methane oxidative coupling catalyst is obtained by roasting a mixture material comprising a nano catalyst intermediate state and a flocculating agent in a protective atmosphere, and the methane oxidative coupling catalyst contains sodium element.
2. The methane oxidative coupling catalyst of claim 1, wherein: the methane oxidative coupling catalyst is selected from lanthanide catalysts loaded with sodium element, preferably the lanthanide catalysts are selected from lanthanum oxycarbonate catalysts, and/or, The mass content of sodium element in the methane oxidative coupling catalyst is 5% -20%, and preferably 5% -15%.
3. The methane oxidative coupling catalyst of claim 1, wherein: the flocculant is at least one selected from polyacrylamide, cellulose and derivatives thereof, lignin and derivatives thereof, chitosan and derivatives thereof.
4. A methane oxidative coupling catalyst according to claim 3, characterized in that: the polyacrylamide is at least one selected from anionic polyacrylamide, cationic polyacrylamide or nonionic polyacrylamide, and/or, The cellulose is selected from sodium carboxymethyl cellulose, and/or, The lignin is selected from dealkalized lignin.
5. The preparation method of the methane oxidative coupling catalyst is characterized by comprising the following steps of: Adding a flocculating agent into the mixed solution containing the intermediate state of the nano catalyst, settling, separating solid from liquid, drying and grinding solid materials, and roasting in a protective atmosphere to obtain the methane oxidative coupling catalyst; the methane oxidative coupling catalyst of any one of claims 1-4 is preferably prepared using the method.
6. The method for preparing the oxidative coupling catalyst for methane according to claim 5, wherein: the mixed solution containing the intermediate state of the nano catalyst comprises the intermediate state of the nano catalyst, sodium element and a solvent; Preferably, the preparation of the mixed solution containing the intermediate state of the nano catalyst comprises the following steps of dropwise adding alkali solution containing sodium into solution containing the precursor of the nano catalyst, and obtaining the mixed solution containing the intermediate state of the nano catalyst after reaction.
7. The method for preparing the oxidative coupling catalyst for methane according to claim 6, wherein: The nanocatalyst precursor is selected from soluble lanthanum salts, preferably from lanthanum nitrate, and/or, In the solution containing the nano catalyst precursor, the concentration of lanthanum element is 0.6wt% -0.8wt%, and/or, The alkali liquor containing sodium element is sodium hydroxide solution, preferably, alkali liquor containing 0.1-0.2g of sodium hydroxide is dropwise added into the solution containing nano catalyst precursor per kilogram per minute until the pH value is adjusted to 11.5-12, and/or, The solution containing the nano catalyst precursor and the solvent in the alkali solution containing the sodium element are water and/or, The temperature of the reaction is room temperature, and/or, The reaction time is 50-70h, and/or, The nano catalyst intermediate is selected from lanthanum hydroxide.
8. The method for preparing the oxidative coupling catalyst for methane according to claim 5, wherein: the mass volume ratio of the flocculant to the mixed solution containing the intermediate state of the nano catalyst is 0.01-5 g/1L, preferably 1-5 g/1L, more preferably 2-4 g/1L, and/or, The sedimentation is a static sedimentation, and/or, The solid-liquid separation mode is suction filtration and/or, The drying temperature is 80-200 ℃, and/or, The drying time is 10-18h, and/or, The grinding time is 20-40min.
9. The method for preparing the oxidative coupling catalyst for methane according to claim 5, wherein: The roasting is carried out at 500-700 ℃ for 2-6h, preferably at 500-600 ℃ for 2-3h, and further preferably the temperature rising rate of the roasting is 2-5 ℃/min.
10. Use of a methane oxidative coupling catalyst according to any one of claims 1-4 or a methane oxidative coupling catalyst prepared by a method according to any one of claims 5-9 in a reaction for the oxidative coupling of methane to ethylene.

Description

Methane oxidative coupling catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of nano catalyst preparation and separation, in particular to a methane oxidative coupling catalyst and a preparation method and application thereof. Background Ethylene is one of the most productive chemical products in the world and plays an important role in national economy. The current source of ethylene production is mainly derived from petroleum. To change the situation that ethylene production raw materials are excessively dependent on petroleum resources, the technology of direct ethylene production from natural gas (methane) (OCM) is receiving a great deal of attention, wherein low temperature nanocatalyst is attracting a great deal of attention due to its higher C 2 hydrocarbon yield and economy. However, the separation of the methane oxidative coupling nano catalyst at present mainly depends on the centrifugal technology of laboratory means, such as centrifugal separation, and the like, and has the advantages of high solid-liquid separation cost, long time consumption and difficult application to catalyst amplification and industrialization processes. Therefore, how to realize the rapid separation of the methane oxidative coupling catalyst is a technical problem which needs to be solved at present. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a methane oxidative coupling catalyst and a preparation method and application thereof. In order to solve the problem of catalyst separation, the invention provides a method and an application scheme for high-efficiency solid-liquid separation in the preparation process of a methane oxidative coupling catalyst, and a high-molecular flocculant is adopted to rapidly separate solid from liquid in the middle state of a low-temperature OCM nano catalyst. Therefore, the method for quickly separating the methane oxidative coupling catalyst can reduce the preparation cost of the catalyst and improve the preparation efficiency of the catalyst. The invention aims to provide a methane oxidative coupling catalyst, which is obtained by roasting a mixture material comprising a nano catalyst intermediate state and a flocculating agent in a protective atmosphere, and contains sodium element. In the methane oxidative coupling catalyst according to the present invention, preferably, The methane oxidative coupling catalyst is selected from lanthanide catalysts loaded with sodium element, preferably the lanthanide catalysts are selected from lanthanum oxycarbonate catalysts, and/or, The mass content of the sodium element in the methane oxidative coupling catalyst is 5% -20%, preferably 5% -15%, such as 5%, 7%, 10%, 12%, 15%, 18% and 20%. In the methane oxidative coupling catalyst according to the present invention, preferably, The flocculant is at least one selected from polyacrylamide, cellulose and derivatives thereof, lignin and derivatives thereof, chitosan and derivatives thereof. In the methane oxidative coupling catalyst according to the present invention, preferably, The polyacrylamide is at least one selected from anionic polyacrylamide, cationic polyacrylamide or nonionic polyacrylamide, and/or, The cellulose is selected from sodium carboxymethyl cellulose, and/or, The lignin is selected from dealkalized lignin. In the technical scheme of the invention, the sodium-containing polyacrylamide is obtained by selecting an initiator containing Na salt in the existing polyacrylamide preparation process, and the flocculant is preferably selected from the sodium-containing flocculant, namely at least one of sodium-containing polyacrylamide, sodium-containing cellulose and derivatives thereof or sodium-containing lignin and derivatives thereof. The second purpose of the invention is to provide a preparation method of the methane oxidative coupling catalyst, which comprises the following steps: Adding a flocculating agent into the mixed solution containing the intermediate state of the nano catalyst, settling, separating solid from liquid, drying and grinding solid materials, and roasting in a protective atmosphere to obtain the methane oxidative coupling catalyst; the oxidative coupling catalyst for methane according to one of the objects of the present invention is preferably prepared by the method. In the preparation method of the methane oxidative coupling catalyst, further preferably, a flocculating agent is added into mixed liquid containing the intermediate state of the nano catalyst, standing and settling are carried out, then the solid-liquid separation mixture is subjected to suction filtration, the filtered product is put into an oven for drying, and the solid product is baked in a protective atmosphere, so that the methane oxidative coupling catalyst is obtained. In the method for producing the oxidative coupling catalyst for methane according to the present invention, prefe