A method for producing olefins from natural gas by catalysis with thermal radiation

Abstract

The application provides a method for producing olefins from natural gas through thermal radiation catalysis, and relates to the field of chemical industry. The method for producing olefins from natural gas through thermal radiation catalysis provided by the application adds photocatalysis generated by thermal radiation to traditional thermal catalysis, improves the catalytic performance, accelerates the reaction speed, improves the conversion rate and improves the selectivity of the catalytic reaction, so that the reaction time can be reduced and the energy consumption can be reduced. In the catalytic process participated by the gas, liquid and solid catalysts with the light spectrum absorption capacity of thermal radiation, the method can further improve the catalytic performance / selectivity / stability and other characteristics on the basis of the original catalytic performance. The application mainly aims at improving the catalytic performance of natural gas for producing olefins, the method has the characteristics of simple operation and smooth operation, and the existing industrial equipment does not need to be modified too much.

Description

Technical Field

[0001] This application relates to the chemical industry, and more particularly to a method for producing olefins from natural gas by thermal radiation catalysis. Background Technology

[0002] With increasingly scarce oil resources, the further development and utilization of natural gas resources is attracting more and more attention. Besides being used directly as fuel, natural gas can also serve as a highly efficient, high-quality, and clean energy source and chemical feedstock. The main component of natural gas is methane, and the comprehensive utilization of methane is broadly divided into two categories: direct conversion and indirect conversion. Direct conversion involves directly converting methane into chemical feedstocks such as ethylene, methanol, formaldehyde, and chloromethane. Indirect conversion involves first converting methane into syngas, and then using the syngas to produce liquid fuels such as methanol and gasoline, as well as synthetic ammonia.

[0003] Indirect methane conversion requires a long time to complete, significant capital investment, and high energy consumption. Direct methane conversion, on the other hand, is a highly energy-efficient process; its main challenge lies in the selective activation and directional conversion of methane. Summary of the Invention

[0004] The purpose of this application is to provide a method for producing olefins from natural gas through thermal radiation catalysis, which aims to solve the problems of existing indirect methane conversion methods that require a long time to complete the conversion, require a large investment, and consume a lot of energy, as well as the difficulties in selective activation and directional conversion of methane in direct methane conversion methods.

[0005] To achieve the above objectives, this application provides a method for producing olefins from natural gas via thermal radiation catalysis. A reaction gas is introduced into a reaction apparatus, wherein the volume ratio of methane in the reaction gas is greater than or equal to 20% and less than 100%, and the volume ratio of ethane is greater than 0 and less than or equal to 80%. The reaction gas is subjected to heating and thermal radiation conditions to catalytically prepare olefins; the thermal radiation includes first thermal radiation generated by the heating heat source.

[0006] Preferably, the temperature at which the reactant gas is heated is 300~1000℃;

[0007] Preferably, the temperature at which the reaction gas is heated is 450~650℃.

[0008] Preferably, the reaction device is further provided with a radiation source, and the thermal radiation also includes a second thermal radiation generated by the radiation source;

[0009] Preferably, the temperature of the radiation source is 300~1500℃;

[0010] Preferably, the temperature of the radiation source is 500~1000℃.

[0011] Preferably, the step of introducing a reaction gas into the reaction apparatus further includes: adding a catalyst to the reaction apparatus, wherein the catalyst can absorb the spectrum of the thermal radiation to increase the surface temperature of the catalyst and improve the internal energy of the reaction system; the catalyst includes any one or more of a gaseous catalyst, a solid catalyst, and a liquid catalyst.

[0012] Preferably, the catalyst comprises a gaseous catalyst, wherein the gaseous catalyst is a gas molecule that has strong spectral absorption of thermal radiation;

[0013] Preferably, the gaseous catalyst comprises any one or both of carbon dioxide and water vapor;

[0014] Preferably, the volume ratio of the reactant gas to the gaseous catalyst is (1000:1) to (1:1000).

[0015] Preferably, the temperature of the reaction gas heating is 550~650℃, and the step of introducing the reaction gas into the reaction device further includes: adding a catalyst to the reaction device, wherein the catalyst can absorb the spectrum of the thermal radiation to increase the surface temperature of the catalyst and improve the internal energy of the reaction system; the catalyst includes any one or more of gaseous catalysts, solid catalysts and liquid catalysts;

[0016] Preferably, the catalyst comprises a gaseous catalyst, wherein the gaseous catalyst is a gas molecule that has strong spectral absorption of thermal radiation;

[0017] Preferably, the gaseous catalyst comprises any one or both of carbon dioxide and water vapor;

[0018] Preferably, the volume ratio of the reactant gas to the gaseous catalyst is (1000:1) to (1:1000).

[0019] Preferably, the reaction device is a tubular reactor, and the reaction gas is introduced into the reaction tube of the reaction device. The reaction tube is made of transparent high-temperature resistant material or high emissivity material.

[0020] Preferably, the reaction device is a tubular reactor, the reaction gas is introduced into the reaction tube of the reaction device, the reaction tube is made of transparent high-temperature resistant material or high emissivity material, and the distance between the radiation source and the heat source and the reaction tube is 0-100cm.

[0021] Preferably, the radiation source is a wound heating wire or heating rod, and the heat source is a wound heating wire or heating rod; the material of the radiation source is metal; and the outer surface of the heat source is coated with corundum and / or ceramic.

[0022] Preferably, the flow rate of the reaction gas is 1-1000 ml / min.

[0023] Compared with the prior art, the beneficial effects of this application include:

[0024] The method for producing olefins from natural gas via thermal radiation provided in this application incorporates photocatalysis generated by thermal radiation into traditional thermal catalysis, thereby improving its catalytic performance, accelerating the reaction rate, increasing the conversion rate, and enhancing the selectivity of the catalytic reaction, which can reduce the reaction time and energy consumption.

[0025] In catalytic processes involving gaseous, liquid, and solid catalysts with thermal radiation spectral absorption capabilities, the method of the present invention can further improve the catalytic performance, selectivity, stability, and other properties on the basis of the original catalytic performance.

[0026] This application mainly focuses on improving the catalytic performance of natural gas to olefins. The method is characterized by simple operation, stable operation, and minimal modification to existing industrial equipment. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0028] Figure 1 This is a schematic diagram of the structure of an embodiment of the reaction apparatus of this application;

[0029] Figure 2 This is a schematic diagram of another embodiment of the reaction apparatus of this application.

[0030] The attached icon is labeled as follows:

[0031] 10-Reaction tube; 11-Inlet; 12-Outlet; 20-Heat source; 30-Cavity; 40-Shell. Detailed Implementation

[0032] As used in this article:

[0033] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0034] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0035] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0036] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0037] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0038] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0039] This application provides a method for producing olefins from natural gas via thermal radiation catalysis. A reaction gas is introduced into a reaction apparatus, wherein the volume ratio of methane in the reaction gas is greater than or equal to 20% and less than 100%, and the volume ratio of ethane is greater than 0 and less than or equal to 80%. The reaction gas is subjected to heating and thermal radiation conditions to catalytically prepare olefins. The thermal radiation includes first thermal radiation generated by the heat source of the heating.

[0040] The reaction gases mainly consist of methane and ethane. The volume ratio of methane can be, for example, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%, and the volume ratio of ethane can be, for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80%. Preferably, in the reaction gases of this application, the volume ratio of methane is greater than or equal to 80% and less than 100%, and the volume ratio of ethane is greater than 0 and less than or equal to 20%.

[0041] The reaction apparatus is used for the thermal radiation catalytic production of olefins from natural gas. The shape and structure of the reaction apparatus are not specifically limited; for example, it can be a cube, cuboid, cylinder, or other irregular shape. The reaction apparatus can be, for example, a chamber reactor or a tubular reactor. In a chamber reactor, the reactant gas is introduced into the reaction chamber for the catalytic reaction; in a tubular reactor, the reactant gas is introduced into the reaction tube for the catalytic reaction.

[0042] Preferably, please refer to Figure 1 and Figure 2 The reaction apparatus is a tubular reactor, comprising a shell 40. The reaction gas is introduced into the reaction tube 10 of the reaction apparatus through the inlet 11 and connected to the detection equipment through the outlet 12. The reaction tube 10 is made of a transparent high-temperature resistant material or a high-emissivity material. For example, the transparent high-temperature resistant material used to prepare the reaction tube can be transparent quartz, thus obtaining a transparent quartz tube; the high-emissivity material used to prepare the reaction tube can be, for example, corundum, sandblasted stainless steel tube, or steel tube coated with blackbody radiation paint, etc.

[0043] The distance between the heat source 20 and the reaction tube 10 can be 0-100cm, for example, 0cm, 5cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm, or 100cm, or any value between 0-100cm. The installation distance determines the temperature and thermal radiation spectrum of the reaction tube 10, and therefore can be adjusted according to the temperature and thermal radiation spectrum required for the actual application. The closer the heat source 20 is to the reaction tube 10, the more favorable the thermal radiation transmission, facilitating the absorption of the thermal radiation spectrum by the catalyst or reaction molecules.

[0044] The evaluation of olefin production from natural gas via thermal radiation catalysis mainly involves two aspects: conversion rate and selectivity. Conversion rate is the ratio of the amount of product to the amount of feedstock; a higher conversion rate indicates a greater yield of olefins. Selectivity refers to the probability of generating the desired product relative to byproducts during a given reaction. The conversion rate and selectivity of olefin production from natural gas via thermal radiation catalysis in this invention can be measured using a gas chromatograph connected externally to the reactor.

[0045] Existing methods for producing olefins from natural gas primarily utilize heating and solid metal catalysts for catalytic reactions. The reaction chambers or tubes of existing reaction devices are typically made of opaque, common, high-temperature-resistant materials. However, the applicant has discovered that the heat source used for heating not only provides temperature but also emits thermal radiation, which generates a thermal radiation spectrum that also has a catalytic effect. Thermal radiation catalysis mainly consists of two parts: first, the thermal radiation transfers heat energy; second, the thermal radiation spectrum can be used to drive photocatalysis, achieving a synergistic photothermal catalytic effect. This strengthens the bond vibrations of the reactant gas molecules, increases the internal energy of the reaction system, and allows olefins to be produced from natural gas without a catalyst.

[0046] Thermal radiation refers to the phenomenon of an object radiating electromagnetic waves due to its temperature. It is one of the three modes of heat transfer. All objects with a temperature above absolute zero can produce thermal radiation; the higher the temperature, the greater the total energy radiated, and the more short-wavelength components are emitted. The spectrum of thermal radiation is a continuous spectrum, theoretically covering wavelengths from 0 to ∞. Typical thermal radiation mainly includes longer wavelengths of visible light and infrared radiation. Therefore, the heat source used in this application can also generate thermal radiation, i.e., first thermal radiation, as one of the conditions for the catalytic oxidation of natural gas to olefins. It is understood that, to increase the energy of thermal radiation, this application can add a radiation source to the heat source, thereby improving reaction efficiency.

[0047] The method for producing olefins from natural gas via thermal radiation provided in this application incorporates photocatalysis generated by thermal radiation into traditional thermal catalysis, thereby improving its catalytic performance, accelerating the reaction rate, increasing the conversion rate, and enhancing the selectivity of the catalytic reaction, which can reduce the reaction time and energy consumption.

[0048] Heating refers to heating the reactant gas at a temperature of 300~1000℃, for example, 300~700℃, 500~1000℃, 400~800℃, or 450~650℃. Preferably, the reactant gas is heated to a temperature of 450~650℃, for example, (450, 500, 550, 600, or 650)℃, or any value between 450~650℃. This temperature can also be referred to as the reaction temperature. The reaction temperature can be maintained, for example, by placing a temperature sensor inside the reaction tube or reaction chamber and using a heat source within the reaction apparatus to keep the reactant gas temperature in the reaction tube or reaction chamber at the set reaction temperature.

[0049] It is understandable that the reaction tube 10 can be heated by an external heat source or by itself being electrically heated, thereby heating the reaction gas inside the reaction tube 10. The reaction tube 10 is made of a transparent, high-temperature resistant material, allowing more heat radiation from the external heat source to penetrate and irradiate the reaction gas inside. Alternatively, the reaction tube 10 can be made of a high-emissivity material, so that after being heated, it can act as a heat source itself, radiating heat to irradiate the reaction gas inside.

[0050] In other embodiments, when the reaction device is a chamber reactor, the reaction gas is directly introduced into the reaction chamber to react, and the heat source directly heats and radiates heat onto the reaction gas. Similar to a tubular reactor, the reaction chamber can also be heated by itself using electricity as a heat source, or a heat source structure containing high emissivity materials, such as heating rods or heating wires, can be installed inside the reaction chamber to generate thermal radiation that irradiates the reaction gas.

[0051] In a preferred embodiment, the reaction apparatus is further provided with a radiation source, and the thermal radiation also includes a second thermal radiation generated by the radiation source. By adding a radiation source on top of the heat source, the efficiency of the catalytic reaction can be improved.

[0052] The temperature of the radiation source is 300~1500℃, for example, it can be 300~800℃, or 700~1300℃, or 600~1000℃, or 500~1000℃, or 500~1500℃. Preferably, the temperature of the radiation source is 500~1000℃, for example, it can be 500℃, 600℃, 700℃, 800℃, 900℃, or 1000℃.

[0053] Alternatively, please continue reading Figure 1 and Figure 2 The tubular reactor can also be equipped with a cavity 30 structure, in which the reaction tube 10 is installed, and the heat source 20 and radiation source are also installed in the cavity 30 structure to facilitate the release of thermal radiation.

[0054] The distance between the radiation source and the reaction tube 10 is 0-100cm, for example, it can be 0cm, 5cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm or 100cm, or any value between 0-100cm. The installation distance determines the magnitude of the second thermal radiation and can be adjusted according to the actual application requirements.

[0055] The radiation source can be a wound heating wire or a heating rod, and the heat source can also be a wound heating wire (such as...). Figure 1 (as shown) or heating rod (such as) Figure 2(As shown); the radiation source is made of metal, and its emissivity is between 0.5 and 0.99, giving it high thermal radiation. Preferably, the radiation source is made of nickel-chromium alloy. Emissivity, usually called emissivity, refers to the ratio of an object's radiation capacity to that of a blackbody at the same temperature. It is generally in the range of [0,1]. The higher the emissivity, the higher the object's thermal radiation.

[0056] A heat source can provide heat or heat radiation. A heat source can provide heat radiation by wrapping its outer surface with corundum and / or ceramic, which are high emissivity materials, thus increasing the emissivity of the heat source. Alternatively, the heat source can also be made of a metal material with high emissivity.

[0057] This application mainly focuses on improving the catalytic performance of natural gas to olefins. The method is characterized by simple operation, stable operation, and minimal modification to existing industrial equipment.

[0058] In a preferred embodiment, the step of introducing a reaction gas into the reaction apparatus further includes: adding a catalyst to the reaction apparatus, the catalyst being capable of absorbing the spectrum of the thermal radiation to increase the surface temperature of the catalyst and improve the internal energy of the reaction system; the catalyst includes any one or more of a gaseous catalyst, a solid catalyst, and a liquid catalyst.

[0059] Specifically, adding a catalyst during the above-mentioned thermal radiation catalytic reaction can increase the catalytic rate. The catalyst has the characteristic of absorbing the spectrum generated by thermal radiation, that is, it can absorb thermal radiation, thereby increasing its own surface temperature and strengthening vibration. Solid and liquid catalysts can also excite photogenerated carriers or excite the generation of surface plasma, promote the activation of reactant gas molecules, and thus accelerate the reaction rate.

[0060] In catalytic processes involving gaseous, liquid, and solid catalysts with thermal radiation spectral absorption capabilities, the method of the present invention can further improve the catalytic performance, selectivity, stability, and other properties on the basis of the original catalytic performance.

[0061] The specific form of the catalyst is not limited; it can be a gas (a substance with a vaporization temperature lower than the catalytic temperature) that has the ability to absorb thermal radiation spectrum, or a liquid (a substance with a melting temperature lower than the catalytic temperature) that has the ability to absorb thermal radiation spectrum, as well as a solid catalyst.

[0062] In one embodiment, the catalyst comprises a gaseous catalyst, which is a gas molecule that strongly absorbs the thermal radiation spectrum; the increased internal energy of the gaseous catalyst molecules facilitates the transfer of kinetic energy during molecular collisions. The gaseous catalyst includes any one or both of carbon dioxide and water vapor, as well as any other gas molecules that can absorb the thermal radiation spectrum.

[0063] More preferably, the gaseous catalyst is water vapor, which has better spectral absorption characteristics and therefore better catalytic performance.

[0064] Preferably, the volume ratio of the reactant gas to the gaseous catalyst is (1000:1) to (1:1000), for example, it can be 2:1, 3:2, 5:3, 10:3, 50:3, 50:23, 100:33, 200:55, 300:57, 400:1 or 500:1.

[0065] In another preferred embodiment, the temperature of the reaction gas is heated to 550~650℃, for example, 550℃, 600℃, or 650℃. No external radiation source is used. Introducing the reaction gas into the reaction apparatus further includes adding a catalyst, the catalyst having the same characteristics as the catalyst in the above embodiments, which will not be described in detail here. Experiments have shown that when there is insufficient thermal radiation to provide enough energy to activate the catalyst water vapor, the water vapor will poison the reaction at low temperatures, slowing down the reaction.

[0066] Preferably, the flow rate of the reactant gas is 1-1000 ml / min, for example, it can be (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000) ml / min, or any value between 1 and 1000 ml / min.

[0067] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0068] For ease of description, the reaction apparatus used in the method for producing olefins from natural gas by thermal radiation in the embodiments of the present invention is described in detail below. Figure 2 Taking a similar tubular reactor as an example, the reaction device includes a shell 40 and a cavity structure 30. A reaction tube 10 and a heat source 20 are arranged within the cavity structure 30. The reaction tube 10 includes an inlet 11 and an outlet 12 for introducing reaction gases. A transparent quartz tube is used as the reaction tube 10. The heat source 20 is a high-emissivity alumina-based electric heating rod. There are a total of six heat sources 20. The distance between the heating rod and the reaction tube 10 is approximately 5 cm. Figure 2The difference is that the heat source 20 is installed parallel and evenly around the reaction tube 10. The radiation source is a spirally wound metal wire, 14.5cm long, made of nickel-chromium alloy, and installed parallel to the reaction tube 10 at a distance of about 5cm.

[0069] Those skilled in the art will understand that the structure of the reaction device described herein is for illustrative purposes only and should not be construed as limiting the scope of this application. The specific structure and parameters of the reaction device can be modified or replaced according to actual applications. Such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0070] Example 1

[0071] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0072] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 450℃, and the total reaction gas flow rate was set at 4 mL / min. The mixture was then introduced into the atmosphere... Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 0.86%, and the ethylene selectivity was 100%.

[0073] Example 2

[0074] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0075] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 500℃, and the total reaction gas flow rate was set at 4 mL / min. The mixture was then introduced into the atmosphere... Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.25%, and the ethylene selectivity was 100%.

[0076] Example 3

[0077] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0078] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 550℃, and the total reaction gas flow rate was set at 4 mL / min. The mixture was then introduced into the atmosphere... Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.17%, and the ethylene selectivity was 81.06%.

[0079] Example 4

[0080] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0081] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 600℃, and the total reaction gas flow rate was set at 4 mL / min. The mixture was then introduced into the atmosphere... Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.15%, and the ethylene selectivity was 79.31%.

[0082] Example 5

[0083] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0084] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 650℃, and the total reaction gas flow rate was set at 4 mL / min. The mixture was then introduced into the atmosphere... Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.65%, and the ethylene selectivity was 80.89%.

[0085] Example 6

[0086] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0087] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 450℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.71%, and the ethylene selectivity was 100%.

[0088] Example 7

[0089] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0090] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 500℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 2.18%, and the ethylene selectivity was 100%.

[0091] Example 8

[0092] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0093] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 550℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 2.66%, and the ethylene selectivity was 89.54%.

[0094] Example 9

[0095] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0096] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 600℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 3.01%, and the ethylene selectivity was 85.25%.

[0097] Example 10

[0098] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0099] The reaction gases were mixed at a volume ratio of 42.5% methane, 7.5% ethane, and 50% Ar. The reaction temperature was set at 650℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 3.72%, and the ethylene selectivity was 88.45%.

[0100] Example 11

[0101] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0102] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 450℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 2.30%, and the ethylene selectivity was 100%.

[0103] Example 12

[0104] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0105] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 500℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 2.54%, and the ethylene selectivity was 100%.

[0106] Example 13

[0107] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0108] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 550℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 4.19%, and the ethylene selectivity was 100%.

[0109] Example 14

[0110] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0111] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 600℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 5.17%, and the ethylene selectivity was 100%.

[0112] Example 15

[0113] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0114] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 650℃, the thermal radiation temperature at 700℃, and the total reaction gas flow rate at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 5.71%, and the ethylene selectivity was 100%.

[0115] Example 16

[0116] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0117] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 450℃, and the total reaction gas flow rate was set at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography indicate that the initial conversion rate was approximately 0%, and the ethylene selectivity was 0%.

[0118] Example 17

[0119] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0120] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 500℃, and the total reaction gas flow rate was set at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography indicate that the initial conversion rate was approximately 0%, and the ethylene selectivity was 0%.

[0121] Example 18

[0122] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0123] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 550℃, and the total reaction gas flow rate was set at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 1.32%, and the ethylene selectivity was 100%.

[0124] Example 19

[0125] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0126] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 600℃, and the total reaction gas flow rate was set at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 2.34%, and the ethylene selectivity was 100%.

[0127] Example 20

[0128] A method for producing olefins from natural gas via thermal radiation catalysis, comprising the following steps:

[0129] The reaction gases were mixed in a volume ratio of 42.5% methane, 7.5% ethane, 47.4% Ar, and 2.6% water vapor. The reaction temperature was set at 650℃, and the total reaction gas flow rate was set at 4 mL / min. Figure 1 In the reaction apparatus shown, after 1 hour of reaction, the results of external gas chromatography showed that the initial conversion rate was approximately 3.26%, and the ethylene selectivity was 100%.

[0130] Table 1 shows the experimental results of catalytic production of olefins from natural gas via thermal radiation in Examples 1 to 20. According to Table 1, Examples 1 to 5, without the addition of water vapor as a catalyst or an external radiation source to provide thermal radiation, can also catalyze the production of olefins from natural gas using only a heated heat source, with a conversion rate of 0.86% to 1.65%. Examples 6 to 10, based on Examples 1 to 5, added an external radiation source to provide thermal radiation, and the corresponding conversion rate was improved at the corresponding reaction temperature, reaching 1.71% to 3.72%. Examples 11 to 15, based on Examples 6 to 10, added water vapor as a catalyst, and the corresponding conversion rate was improved at the corresponding reaction temperature, reaching 2.30% to 5.71%.

[0131] In addition, Examples 16 to 20 added water vapor as a catalyst based on Examples 1 to 5, but without an external radiation source. As a result, no conversion occurred at reaction temperatures of 450°C and 500°C, but at 550-650°C, the conversion rate was improved compared to Examples 3 to 5, by 1.32%, 2.34%, and 3.26%, respectively. This indicates that water vapor as a catalyst can improve the reaction conversion rate, but if there is insufficient thermal radiation to provide enough energy to activate the water vapor, the water vapor will poison the reaction at low temperatures, thus slowing down the reaction.

[0132] Table 1. Experimental results of natural gas to ethylene production in Examples 1 to 20

[0133]

[0134] The data in Table 1 show that as the reaction temperature increases, the methane conversion rate gradually increases, eventually reaching 5.71% when water vapor is added as a catalyst and an external radiation source is added.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0136] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for producing olefins from natural gas by catalytic thermal radiation, characterized in that, The reaction gas is introduced into a reaction device, wherein the volume ratio of methane is greater than or equal to 20% and less than 100%, and the volume ratio of ethane is greater than 0 and less than or equal to 80%; the reaction gas is catalytically prepared into olefins under heating and thermal radiation; the thermal radiation includes first thermal radiation generated by a heat source of the heating; The reaction device is further provided with a radiation source, and the thermal radiation further includes second thermal radiation generated by the radiation source; The reaction gas is introduced into the reaction device, and a catalyst is added into the reaction device, wherein the catalyst can absorb the spectrum of the thermal radiation, so that the surface temperature of the catalyst is increased and the internal energy of the reaction system is increased; the catalyst is water vapor; The temperature of the reaction gas is 300-1000℃. The temperature of the radiation source is 500-1000℃.

2. The method for producing olefins from natural gas via thermal radiation catalysis according to claim 1, characterized in that, The temperature of the reaction gas is 450-650℃.

3. The method for producing olefins from natural gas via thermal radiation catalysis according to claim 1, characterized in that, The volume ratio of the reaction gas to the catalyst is (1000:1)-(1:1000).

4. The method for producing olefins from natural gas via thermal radiation catalysis according to claim 1, characterized in that, The reaction device is a tubular reactor, the reaction gas is introduced into a reaction tube of the reaction device, the reaction tube is made of transparent high-temperature resistant material or high-radiation material, and the distance between the radiation source and the heat source and the reaction tube is 0-100 cm.

5. The method of producing olefins by catalytic natural gas through thermal radiation according to claim 4, characterized in that, The radiation source is a wound heating wire or a heating rod, and the heat source is a wound heating wire or a heating rod; the material of the radiation source is metal, and the emissivity of the metal is 0.5-0.

99.

6. The method of producing olefins by catalytic natural gas through thermal radiation according to claim 4, characterized by, The outer surface of the heat source is wrapped with corundum and / or ceramic.

7. The method of producing olefins by catalytic natural gas through thermal radiation according to claim 4, characterized by, The material of the radiation source is nickel-chromium alloy.

8. The method of producing olefins by catalytic natural gas through thermal radiation according to claim 1, characterized by, The flow rate of the reaction gas is 1-1000 ml / min.

Images