A process for the catalytic conversion of methane to olefins, aromatics and hydrogen under oxygen-free conditions

Abstract

The present application relates to a kind of methods for catalyzing methane to olefin, aromatic and hydrogen under anaerobic condition, the lattice of catalyst active component is doped with the substrate pipe of coating in the contact surface of metal pipe and reaction raw material, form catalytic dopant thin layer on the contact surface of metal pipe and reaction raw material, obtain the metal catalytic reactor for the method reaction of methane to olefin, aromatic and hydrogen, can realize the efficient conversion of methane, high catalyst stability and zero carbon generation.The conversion rate of methane of the present application is 25-80%;Olefin selectivity is 60-90%;Aromatic selectivity is 0-20%;Zero carbon.This application has the characteristics of long catalyst life, high methane conversion and product selectivity, zero carbon, catalyst does not need to be enlarged, industrialization is difficult, product is easy to separate, process repeatability is good, operation is safe and reliable, etc., has wide industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysis, and particularly relates to a method for catalyzing methane to olefins, aromatic hydrocarbons and hydrogen under oxygen-free conditions, which realizes efficient conversion of methane to high-value chemicals, and has the characteristics of excellent catalyst stability and zero carbon deposition. BACKGROUND

[0002] Development and effective utilization of natural gas (methane) resources represent the development direction of contemporary energy structure, and is one of the important ways for sustainable development and energy greenization. However, how to efficiently utilize gaseous carbon-hydrogen resources (methane) has become an important link restricting the development of China's energy industry, and converting this abundant resource into fuel and high-value chemicals (especially low-carbon olefins) has aroused worldwide interest again, and is also an important step to improve China's energy structure. Low-carbon olefins, such as ethylene, are very important raw materials or intermediates in chemical and chemical processes. Traditional low-carbon olefins (C2-C4) are mainly derived from petroleum cracking and other petrochemical processes, so the production of ethylene has become a symbol of the level of oil and chemical production in a country or region. With the increasing depletion of oil resources, exploring non-traditional routes to produce low-carbon olefins has become the focus of current research. Some typical alternative routes have emerged, such as starting from synthesis gas to obtain low-carbon olefins through methanol or dimethyl ether, but this route is complex and has low atom economy. In order to shorten the reaction path, a large amount of research has been conducted on the Fischer-Tropsch route to directly synthesize low-carbon olefins from synthesis gas. However, the above-mentioned alternative routes must consume CO or H2 to remove O in CO, which will inevitably result in a C atom utilization rate of less than 50%. Despite the high energy input, large amount of CO2 emission and less than 50% atom utilization rate, the indirect process still dominates in the natural gas industry.

[0003] In contrast, direct conversion of natural gas has great economic potential and is more environmentally friendly. However, direct conversion of natural gas is still a challenge in chemistry and chemical engineering. The main component of natural gas is methane, which has a high C—H bond energy of 434 kJ / mol, and the methane molecule itself has little electronic affinity. In addition, it has a large ionization energy and a small polarizability, so the activation of the C—H bond of methane is considered to be the ―holy grail” of chemistry. Keller and Bhasin reported the activation of the C—H bond of methane with the participation of O2, and their pioneering work sparked enthusiasm for the study of methane oxidative coupling to ethylene at high temperatures (> 1073 K) worldwide. During this period, hundreds of catalytic materials were synthesized and tested, and research peaked in the 1990s. In the oxidative coupling process, the introduction of molecular oxygen (O2) inevitably leads to the over-oxidation of methane and its products, resulting in a large amount of thermodynamically more stable products such as CO2 and H2O, ultimately leading to a relatively low utilization efficiency of C atoms. Due to the bottleneck of new material and new catalyst development, the methane oxidative coupling process has stagnated, and so far there have been few reports of economically viable new processes. A recent study proposed using weakly oxidizing gas-phase S instead of molecular oxygen O2 to perform methane oxidative coupling reactions. At a temperature of 1323 K (reaction gas: 5% CH4 / Ar), the optimal PdS / ZrO2 catalyst can achieve a methane conversion rate of 16%, but the selectivity of C2H4 is only about 20%, and a large amount of CS2 and H2S is produced as by-products. The above studies show that the activation of methane with oxygen (or oxidants) will inevitably lead to over-oxidation.

[0004] Therefore, direct conversion of methane without oxygen (or oxygenate) is considered as the most ideal route for methane activation. Under the condition of no oxygen (or oxygenate), the over-oxidation of methane or product can be effectively avoided, the emission of greenhouse gas CO2 is inhibited, and the utilization of C atom is improved. The challenges of direct catalytic conversion of methane to ethylene are: 1) controllable activation of methane to break the first C—H bond; 2) inhibition of deep dehydrogenation of methane on the surface of the catalyst; 3) avoidance of the production of greenhouse gas CO2 and carbon deposition. Among them, 1 and 2 are for the catalyst, and 3 is for the reaction process. The over-oxidation of product is inevitable for the process with oxygen, resulting in the inevitable production of CO2. Only the process without oxygen can avoid the production of CO2, but it is easy to deposit carbon, so how to avoid carbon deposition has become the focus of attention in the process without oxygen. The key to solving the problem of carbon deposition is to understand the source of carbon deposition. Taking the process of aroamticization without oxygen as an example, the main sources of carbon deposition are: deep dehydrogenation of methane on the surface of Mo species of the catalyst (―graphitized carbon-like carbon deposition”); cyclization and coupling of product on the B acid site of the carrier molecular sieve channel or orifice (―polyaromatic carbon deposition”). Therefore, the three challenges of direct conversion of methane to ethylene are in the design and construction of the catalyst.

[0005] In 1993, researchers from Dalian Institute of Chemical Physics first reported the continuous flow mode CH4aromaticization reaction on Mo / HZSM-5 catalyst. At 973 K and normal pressure, the CH4conversion rate is about 6%, and the selectivity of aromatic hydrocarbon is more than 90% (not counting the carbon deposition of the reaction), which is an important milestone in the study of CH4aromaticization process without oxygen. In the past decade, the research work of scientists from many countries has mainly focused on the preparation and development of catalysts, reaction and deactivation mechanism, etc., but the rapid carbon deposition and deactivation of the catalyst restricts its further industrial scale-up.

[0006] Recently, the composite catalyst prepared by the biomimetic method of US siluria company (US201241246, US2013165728, US2014121433, CA2837201, US8921256B29) has a methane conversion rate of 26% and an ethylene selectivity of 52% in the oxidative coupling reaction at 600-650℃. For the selective oxidation of methane to prepare methanol or formaldehyde, the oxidation rate of target product methanol and formaldehyde is much faster than that of raw material methane, resulting in low selectivity of the reaction and difficult scale application.

[0007] Two patents have been applied for in the early stage (application numbers: 201310174960.5, 201511003407.0, the two patents mainly apply for a metal-doped silicon-based catalyst, which is then placed in a reactor to catalytically convert methane to olefins in a fixed bed or fluidized bed or moving bed; the two methods have the disadvantages of large pressure drop of the catalyst bed, poor heat conduction of the catalyst, large temperature difference of the bed, harsh catalyst preparation conditions, and difficulty in scaling up, etc. SUMMARY

[0008] The present application further studies the reasons for the above problems in the process of catalytic conversion of oxygen-free methane to olefins, aromatics and hydrogen (MTOAH). From the CFD simulation of the temperature of the fixed bed catalyst, it can be seen that the temperature from the inner wall of the reactor to the axial center of the catalyst bed shows an inverted parabolic trend, i.e. the overall temperature of the catalyst bed is not uniform and the axial center temperature is the lowest; at the same time, the MTOAH reaction is a strong endothermic process, which will further exacerbate the non-uniformity of the bed temperature distribution, which will lead to a serious lack of heat in the part far from the wall surface and difficulty in improving the conversion rate.

[0009] In order to solve the problem, the present application provides a method for catalytically converting methane to olefins, aromatics and hydrogen under oxygen-free conditions, which effectively overcomes the axial temperature difference and avoids the generation of carbon deposition.

[0010] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0011] A method for catalytically converting methane to olefins, aromatics and hydrogen under oxygen-free conditions, which uses a metal catalytic reactor to react, and directly catalytically converts methane as a raw material gas into olefins, aromatics and hydrogen;

[0012] The metal catalytic reactor comprises a metal tube and a catalyst active component, the catalyst active component is coated on the contact surface of the metal tube and the reaction raw material to form a thin layer of catalytic dopant on the contact surface of the metal tube and the reaction raw material, the catalyst active component and the base metal of the contact surface of the metal tube form a catalyst, and the contact surface refers to the inner wall and / or outer wall of the metal tube.

[0013] In the above technical scheme, the thickness of the thin layer of catalytic dopant is 100 nanometers-1 millimeter. Preferably, it is 200 nanometers-0.5 millimeter, more preferably 500 nanometers-200 micrometers, and further preferably 1 micrometer-50 micrometers.

[0014] In the technical scheme, the doping is lattice doping; the catalyst active component is a metal element or a mixture of a metal element and a non-metal element, and the doping amount of the metal element is 0.1-20wt.%, preferably 0.1-15wt.%, and further preferably 0.1-5wt.% based on the total weight of the thin layer of the dopant. The lattice doping refers to that the doping metal element forms a chemical bond with certain elements in the substrate metal material, so that the doping metal element is limited in the lattice of the doping substrate, thereby generating specific catalytic performance.

[0015] In the technical scheme, the existing state of the metal element is one or more of an oxide, a carbide, a nitride, a silicide, and an alloy; and the metal element includes one or more of magnesium, aluminum, calcium, barium, titanium, manganese, vanadium, niobium, tungsten, molybdenum, chromium, iron, cobalt, nickel, copper, zinc, tin, gallium, zirconium, lanthanum, cerium, ruthenium, gold, palladium, or platinum. Preferably, the metal element includes one or more of aluminum, barium, titanium, manganese, vanadium, niobium, tungsten, molybdenum, chromium, iron, cobalt, nickel, copper, zinc, gallium, gold, lanthanum, cerium, ruthenium, gold, palladium, or platinum.

[0016] In the technical scheme, the material of the base metal tube includes one or more than two combinations of GH1015, GH1040, GH1131, GH1140, GH2018, GH2036, GH2038, GH2130, GH2132, GH2135, GH2136, GH2302, GH2696, GH3030, GH3039, GH3044, GH3028, GH3128, GH3530, GH3536, GH605, GH600, GH4033, GH4037, GH4043, GH4049, GH4133, GH4133B, GH4169, GH4145, Hastelloy G-30, Hastelloy G-35, Hastelloy N, Hastelloy S, Inconel 600, Inconel 601, Inconel 601GC, Inconel 617, Inconel 622, Inconel 625, Inconel 625LCF, Inconel 671, Inconel 672, Inconel 686, Inconel 690, Inconel 706, Inconel 718, Inconel 718SPF, Inconel 725, Inconel X-750, Inconel 751, Inconel 754, Inconel 758, Inconel 783, Incoloy DS, Incoloy 800, Incoloy 800H, Incoloy 802, Incoloy 803, Incoloy 804, Incoloy 825, Incoloy 903, Incoloy 907, Incoloy 909, Incoloy 925, Incoloy MA956, Incoloy A-286, Incoloy 25-6Mo, Monel 400.

[0017] In the technical scheme, the metal catalytic reactor is prepared by using the following coating doping technology: one or more than two combinations of electrochemical deposition method, conversion deposition precipitation method, electroplating, electroless plating, electrochemical deposition method, conversion deposition precipitation method, chemical vapor deposition method (CVD), physical vapor deposition method (PVD).

[0018] The following preparation process aims to improve the dispersion and adhesion of metal elements on the surface of the metal base.

[0019] The electrochemical deposition method includes the following steps:

[0020] (1) The base pipe is cooked in 10-20wt.% NaOH or KOH solution for 1-2h for deoiling treatment, and is rinsed and dried at room temperature for standby;

[0021] (2) The base pipe treated in step (1) is heated in hot N2 atmosphere, the heating temperature is 300-500℃, and the heating time is 1-2h to form a corrosion-resistant conductive film layer;

[0022] (3) At room temperature, an aqueous or organic solution of a doped metal element precursor is prepared, the pH value of the solution is adjusted to 3.3-6.5, the metal pipe to be doped is immersed in the doped metal element precursor solution, a power supply is connected, platinum is used as an anode, and the distance between the cathode and the anode is adjusted to 2-5cm after the circuit is connected. The direct current stabilized power supply is adjusted to maintain a constant current mode, the current is 5mA-0.5A, and the metal pipe is electrodeposited for 0.5-2h. After the deposition is completed, the metal catalytic reactor is obtained after washing with deionized water and drying.

[0023] Or the conversion deposition precipitation method, comprising the following steps:

[0024] (1) The base pipe is cooked in 10-20wt.% NaOH or KOH solution for 1-2h for deoiling treatment, and is rinsed and dried at room temperature for standby;

[0025] (2) The base pipe treated in step (1) is heated in hot N2 atmosphere, the heating temperature is 300-500℃, and the heating time is 1-2h to form a corrosion-resistant conductive film layer;

[0026] (3) At room temperature, an aqueous or organic solution of a doped metal element precursor is prepared, the pH value of the solution is adjusted to 3.8-7.2, the metal pipe to be doped is immersed in the doped metal element precursor solution, and the solution is in a flowing state inside the metal pipe to be deposited. Then, 10-20wt.% H2O2 aqueous solution is added for conversion deposition precipitation, the deposition time is 0.5-5h, and the metal catalytic reactor is obtained after the deposition is completed.

[0027] In the above technical solution, the doped metal element precursor used in the electrochemical deposition method is one or two or more of nitrate, soluble halide, soluble sulfate, soluble carbonate, soluble phosphate, soluble methanol salt, soluble ethanol salt, soluble formate, and soluble acetate of the metal;

[0028] The doped metal element precursor used in the conversion deposition precipitation method is one or two or more of chloride, methanol salt, ethanol salt, formate, and acetate of the metal.

[0029] In the technical solution, the catalytic reaction temperature is 750-1200℃, preferably 900-1150℃; the reaction raw material gas flow is 1-100L / min.

[0030] In the technical solution, the reaction raw material gas composition includes methane or a mixed gas of methane and other gases, the other gases including one or both of inert atmosphere gases and non-inert atmosphere gases;

[0031] The inert atmosphere gas is one or more of nitrogen, helium, neon, argon, and krypton, and the volume content of the inert atmosphere gas in the reaction raw material gas is 0-95%;

[0032] The non-inert atmosphere gas is a mixture of one or more of carbon monoxide, hydrogen, and C2-4 alkanes, and the volume content ratio of the non-inert atmosphere gas to methane is 0-10%;

[0033] The volume content of methane in the reaction raw material gas is 5-100%;

[0034] In the technical solution, the reaction process is a continuous flow reaction mode, and when continuous reaction is performed, the reaction pressure is 0.05-1MPa, preferably 0.1-0.5Mpa; and the mass space velocity of the reaction raw material gas is 1.0-100.0L / g / h.

[0035] In the technical solution, the aromatic hydrocarbon product includes one or more of benzene, toluene, p-xylene, o-xylene, m-xylene, ethylbenzene, and naphthalene.

[0036] Based on long-term research on the catalytic conversion of methane under anaerobic conditions, the present application proposes a method for directly producing ethylene, aromatic hydrocarbons, and hydrogen from methane under anaerobic conditions by coating and doping a catalyst active component on the contact surface between a metal tube and a reaction raw material, forming a thin layer of catalytic dopant on the contact surface between the metal tube and the reaction raw material, and forming a catalyst on the contact surface between the catalyst active component and the base metal of the metal tube. Compared with previous methane anaerobic conversion processes, especially the patents with the authorization numbers CN 111333479B, CN 111333477A, and CN 111333478B, the method has the following characteristics:

[0037] Table 1

[0038]

[0039]

[0040] Therefore, the method has the characteristics of high catalyst stability, high methane conversion rate, high product selectivity, zero carbon deposition, good process repeatability, safe and reliable operation, and has a broad industrial application prospect.

[0041] The beneficial effects of the present application are:

[0042] The present application integrates the catalyst active metal component into a nickel-chromium special alloy steel with a unique shape to make an integrated metal catalytic reactor, so that the catalyst and the reactor are integrated. This method has the following advantages:

[0043] (1) The integrated metal alloy catalytic reactor has the characteristics of simple process, milder conditions, and more uniform dispersion of metal active components compared to quartz and silicon carbide doping processes;

[0044] (2) Compared with traditional granular catalysts, the reaction process avoids catalyst axial or radial temperature difference. Because when the catalyst is filled in the reactor, and the catalyst itself has poor thermal conductivity, which leads to an increase in bed radial temperature difference (from the reactor wall to the center, the temperature shows a gradually decreasing trend), so in order to make the center part of the catalyst reach the reaction temperature, more heat needs to be supplied, resulting in heat loss and more side reactions near the wall (high temperature end).

[0045] (3) Compared with granular catalysts, there is no bed pressure drop, and the reaction process is more stable.

[0046] (4) Compared with granular catalysts, the problem of scaling is overcome.

[0047] (5) The metal catalytic reactor prepared by the present application has the characteristics of high catalyst stability, high methane conversion rate, high product selectivity, zero carbon deposition, good process repeatability, and safe and reliable operation in the catalytic conversion of methane to olefins, aromatics and hydrogen. Among them, the conversion rate of methane is 25-80%; zero carbon deposition. This method has the characteristics of long catalyst life, high methane conversion rate, zero carbon deposition, easy separation of products, no need to scale up the catalyst, small difficulty in industrialization, good process repeatability, safe and reliable operation, etc., and has broad industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 La-Ce-Fe prepared for Example 18 Particle induced X-ray emission (PIXE) analysis of Inconel 600 metal catalytic reactor. DETAILED DESCRIPTION

[0049] However, the following examples are only for the purpose of explaining the present application, and the protection scope of the present application should include the entire content of the claims, not just the examples. In addition, the concentrations of NaOH solution, metal precursor solution and H2O2 solution described in the following examples and comparative examples refer to mass percentage concentration.

[0050] I. Preparation of catalytic reactor

[0051] Comparative Example 1

[0052] Inconel 601 alloy tubes (id 10 od 14) were selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature. Subsequently, the tubes were treated at 300 °C under continuous flow of 200 ml / min of N2for 2 h. The tubes were then treated at 500 °C under high purity hydrogen atmosphere for 2.5 h. The blank metal catalytic reactor was obtained, i.e. the blank. Inconel 601 metal catalytic reactor.

[0053] Example 1

[0054] Electrochemical deposition method

[0055] GH3030 and GH3530 alloy tubes (id 15 od 20) were selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature. Subsequently, the tubes were treated at 300 °C under continuous flow of 200 ml / min of N2for 2 h. A 10% aqueous solution of RuCl3was prepared in 2 L, 20 ml of 0.1 mol / L citric acid was added and the pH was adjusted to 4.5 with hydrochloric acid. A 0.5 mm platinum wire was connected as anode and the GH3030 and GH3530 alloy tubes were connected as cathodes. A power supply was connected and the distance between the platinum wire and the alloy tubes was 2 cm. A constant current mode was used and the current was set to 20 mA. After 0.5 h of deposition, Ru-deposited GH3030 and GH3530 alloy tubes were obtained, respectively. Subsequently, the tubes were treated at 500 °C under high purity hydrogen atmosphere for 2 h. A thin layer of Ru dopant of 100 nm thickness was formed at the contact surface of the reactor and then the tubes were naturally cooled. Ru GH3030 and Ru GH3530 metal catalytic reactors, wherein the amount of Ru dopant was 0.5 wt.%.

[0056] Example 2

[0057] Electrochemical deposition method

[0058] GH3030 alloy tube (id 12 od 16) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, then treated at 300°C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 10% RuCl3and 15% FeCl3was prepared in 2 L, 30 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 4.5 with hydrochloric acid. A 0.5 mm platinum wire was connected as an anode, and the GH3030 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used, and the current was set to 25 mA. After 0.5 h of deposition, a Ru and Fe deposited GH3030 alloy tube was obtained. Then, the tube was treated at 500°C under high-purity hydrogen atmosphere for 2 h, a 110 nm thick Ru and Fe dopant thin layer was formed on the contact surface of the reactor, and then the tube was naturally cooled, thereby obtaining a Ru-Fe GH3030 metal catalytic reactor, in which the doping amounts of Ru and Fe were 0.8 wt.% and 1 wt.% respectively.

[0059] Example 3

[0060] Electrochemical deposition method

[0061] Inconel 601 alloy tube (id 10 od 14) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, then treated at 300°C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 20% Co(NO3)2and 15% FeCl3was prepared in 2 L, 20 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 3.8 with hydrochloric acid. A 0.5 mm platinum wire was connected as an anode, and the Inconel 601 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used, and the current was set to 25 mA. After 1 h of deposition, a Co and Fe deposited Inconel 601 alloy tube was obtained. Then, the tube was treated at 500°C under high-purity hydrogen atmosphere for 2.5 h, a 110 nm thick Co and Fe dopant thin layer was formed on the contact surface of the reactor, and then the tube was naturally cooled, thereby obtaining a Co-Fe Inconel 601 metal catalytic reactor, in which the doping amounts of Co and Fe were 1.5 wt.% and 0.6 wt.% respectively.

[0062] Example 4

[0063] Electrochemical deposition method

[0064] Inconel 601 alloy tube (id 10 od 14) was selected and treated by boiling in 15% NaOH solution for 1 h to remove oil, washed with distilled water and air dried at room temperature. The tube was then treated at 300°C under continuous flowing N2atmosphere at 200 ml / min for 2 h. A mixed aqueous solution of 20% Ni(NO3)2and 15% Co(NO3)2was prepared at 2 L, 19 ml of 0.1 mol / L citric acid was added and the pH was adjusted to 3.8 with nitric acid. A 0.5 mm platinum wire was connected as an anode and the Inconel 601 alloy tube was connected as a cathode. A power supply was connected and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used and the current was set at 30 mA. After 1 h of deposition, a Co and Ni deposited Inconel 601 alloy tube was obtained. The tube was then treated at 500°C under high purity hydrogen atmosphere for 2.5 h to form a 110 nm thick Co and Ni dopant layer at the reactor interface and then naturally cooled to obtain a Ni-Co Inconel 601 metal catalytic reactor with 1.5 wt.% and 1.1 wt.% of Ni and Co doping, respectively.

[0065] Example 5

[0066] Electrochemical deposition method

[0067] Inconel 600 alloy tube (id 16 od 20) was selected and treated by boiling in 15% NaOH solution for 1 h to remove oil, washed with distilled water and air dried at room temperature. The tube was then treated at 300°C under continuous flowing N2atmosphere at 200 ml / min for 2 h. A mixed aqueous solution of 10% RuCl3and 15% Cu(NO3)2was prepared at 2 L, 32 ml of 0.1 mol / L citric acid was added and the pH was adjusted to 4.1 with nitric acid. A 0.5 mm platinum wire was connected as an anode and the Inconel 600 alloy tube was connected as a cathode. A power supply was connected and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used and the current was set at 25 mA. After 1 h of deposition, a Ru and Cu deposited Inconel 600 alloy tube was obtained. The tube was then treated at 500°C under high purity hydrogen atmosphere for 2 h to form a 120 nm thick Ru and Cu dopant layer at the reactor interface and then naturally cooled to obtain a Ru-Cu Inconel 600 metal catalytic reactor with 0.5 wt.% and 0.6 wt.% of Ru and Cu doping, respectively.

[0068] Example 6

[0069] Electrochemical deposition method

[0070] Incoloy 800 alloy tube (id 15 od 20) was selected and boiled in 15% NaOH solution for 1 h for deoiling treatment, washed with distilled water and air dried at room temperature, then treated at 300 °C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 20% Ni(NO3)2and 15% Co(NO3)2was prepared at 2 L, 36 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 4.3 with nitric acid. A 0.5 mm platinum wire was connected as an anode, and the Incoloy 800 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 1 cm. A constant current mode was used, and the current was set to 80 mA. After 1 h of deposition, the Incoloy 800 alloy tube with Ni and Co deposition was obtained. Then, it was treated at 500 °C under a high-purity hydrogen atmosphere for 2 h, a 150 nm thick layer of Ni and Co dopant was formed on the contact surface of the reactor, and then it was naturally cooled, i.e., a Ni-Co Incoloy 800 metal catalytic reactor, in which the doping amounts of Ni and Co were 2 wt.% and 1.2 wt.% respectively.

[0071] Example 7

[0072] Electrochemical deposition method

[0073] Monel 400 alloy tube (id 15 od 20) was selected and boiled in 15% NaOH solution for 1 h for deoiling treatment, washed with distilled water and air dried at room temperature, then treated at 300 °C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 20% Ni(NO3)2and 15% Co(NO3)2was prepared at 2 L, 41 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 4.3 with nitric acid. A 0.5 mm platinum wire was connected as an anode, and the Incoloy 800 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 1 cm. A constant current mode was used, and the current was set to 80 mA. After 1 h of deposition, the Incoloy 800 alloy tube with Ni and Co deposition was obtained. Then, it was treated at 500 °C under a high-purity hydrogen atmosphere for 2 h, a 150 nm thick layer of Ni and Co dopant was formed on the contact surface of the reactor, and then it was naturally cooled, i.e., a Ni-Co Monel 400 metal catalytic reactor, in which the doping amounts of Ni and Co were 2 wt.% and 1.2 wt.% respectively.

[0074] Example 8

[0075] Electrochemical deposition method

[0076] Inconel X-750 alloy tube (id 15 od 20) was selected and boiled in 15% NaOH solution for 1 h for deoiling. It was washed with distilled water and air dried at room temperature. It was then treated at 300°C under continuous flow of 200 ml / min N2for 2 h. A mixed aqueous solution of 20% Ni(NO3)2and 15% Zn(NO3)2was prepared in 2 L. 31 ml of 0.1 mol / L citric acid was added and the pH was adjusted to 4.3 with nitric acid. A 0.5 mm platinum wire was connected as an anode and Incoloy 800 alloy tube was connected as a cathode. A power supply was connected and the distance between the platinum wire and the alloy tube was 1 cm. A constant current mode was used and the current was set to 100 mA. After 1 h of deposition, Ni and Zn deposited Inconel X-750 alloy tube was obtained. It was then treated at 500°C under high purity hydrogen atmosphere for 2 h to form a 180 nm thick layer of Ni and Zn dopant on the reactor contact surface. It was then naturally cooled to obtain Ni-Zn Inconel X-750 metal catalytic reactor with 2 wt.% and 1.2 wt.% of Ni and Zn doping respectively.

[0077] Example 9

[0078] Electrochemical deposition method

[0079] Hastelloy G-30 alloy tube (id 16 od 20) was selected and boiled in 15% NaOH solution for 1 h for deoiling. It was washed with distilled water and air dried at room temperature. It was then treated at 300°C under continuous flow of 200 ml / min N2for 2 h. A mixed aqueous solution of 25% Ni(NO3)2and 15% La(NO3)3was prepared in 2 L. 26 ml of 0.1 mol / L citric acid was added and the pH was adjusted to 4.3 with nitric acid. A 0.5 mm platinum wire was connected as an anode and Hastelloy G-30 alloy tube was connected as a cathode. A power supply was connected and the distance between the platinum wire and the alloy tube was 1 cm. A constant current mode was used and the current was set to 100 mA. After 1 h of deposition, Ni and La deposited Hastelloy G-30 alloy tube was obtained. It was then treated at 500°C under high purity hydrogen atmosphere for 2 h to form a 180 nm thick layer of Ni and La dopant on the reactor contact surface. It was then naturally cooled to obtain Ni-La Hastelloy G-30 metal catalytic reactor with 2.5 wt.% and 1.6 wt.% of Ni and La doping respectively.

[0080] Example 10

[0081] Electrochemical deposition method

[0082] Inconel 600 alloy tube (id 10 od 14) was selected and boiled in 15% NaOH solution for 1 h for deoiling treatment, washed with distilled water and air dried at room temperature, then treated at 300°C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 10% chloroauric acid and 15% La(N03)3was prepared in 2 L, 35 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 4.1 with nitric acid. A 0.5 mm platinum wire was connected as an anode, and a GH2130 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used, and the current was set to 30 mA. After 1 h of deposition, an Inconel 600 alloy tube with Au and La deposition was obtained. Then, the alloy tube was treated at 500°C under a high-purity hydrogen atmosphere for 2 h, a 120 nm thick Au and La dopant thin layer was formed on the contact surface of the reactor, and then the alloy tube was naturally cooled, thereby obtaining a Ni-La Inconel 600 metal catalytic reactor, in which the doping amounts of Au and La were 0.5 wt.% and 0.8 wt.% respectively.

[0083] Example 11

[0084] Electrochemical deposition method

[0085] GH4169 alloy tube (id 12 od 18) was selected and boiled in 15% NaOH solution for 1 h for deoiling treatment, washed with distilled water and air dried at room temperature, then treated at 300°C under continuous flowing N2atmosphere of 200 ml / min for 2 h. A mixed aqueous solution of 25% Ni(N03)2, 16% Al(N03)3and 15% Fe(N03)3was prepared in 2 L, 30 ml of 0.1 mol / L citric acid was added, and the pH was adjusted to 4.0 with nitric acid. A 0.5 mm platinum wire was connected as an anode, and a GH4169 alloy tube was connected as a cathode. A power supply was connected, and the distance between the platinum wire and the alloy tube was 2 cm. A constant current mode was used, and the current was set to 100 mA. After 1 h of deposition, a GH4169 alloy tube with Ni, Al and Fe deposition was obtained. Then, the alloy tube was treated at 500°C under a high-purity hydrogen atmosphere for 2 h, a 160 nm thick Ni, Al and Fe dopant thin layer was formed on the contact surface of the reactor, and then the alloy tube was naturally cooled, thereby obtaining a Ni-Al-Fe GH4169 metal catalytic reactor, in which the doping amounts of Ni, Al and Fe were 2.5 wt.%, 1.5 wt.% and 1.2 wt.% respectively.

[0086] Example 12

[0087] Electrochemical deposition method

[0088] Incoloy 903 alloy tube (id 14 od 18) was selected, steamed in 15% NaOH solution for 1 h for degreasing, washed with distilled water and air dried at room temperature, then treated at 300°C for 2 h under a continuous flow of 200 ml / min N2. A 2 L aqueous solution of 25% La(N03)3, 15% Ce(N03)3 and 15% Fe(N03)3 was prepared, 22 ml of 0.1 mol / L citric acid was added, the pH was adjusted to 3.6 with nitric acid, a 0.5 mm platinum wire was connected as an anode, the Incoloy 903 alloy tube was connected as a cathode, and a power supply was connected, with the platinum wire 2 cm from the alloy tube. A constant current mode was used, with a current of 200 mA set, and after 1 h of deposition, La, Ce and Fe deposited Incoloy 903 alloy tube was obtained. Subsequently, it was treated at a temperature of 500°C under a high-purity hydrogen atmosphere for 2 h, forming a 180 nm thick layer of Ni, Al and Fe dopant on the reactor contact surface, and then naturally cooled, obtaining La-Ce-Fe Incoloy 903 metal catalytic reactor, with La, Ce and Fe doping amounts of 3 wt.%, 2.8 wt.% and 1.1 wt.% respectively.

[0089] Example 13

[0090] Conversion deposition precipitation method

[0091] Incoloy 800 alloy tube (id 12 od 18) was selected, steamed in 15% NaOH solution for 1 h for degreasing, washed with distilled water and air dried at room temperature, then treated at 300°C for 2 h under a continuous flow of 200 ml / min N2. A 2 L aqueous solution of 10% Ce(N03)2 was prepared, 25 ml of 0.1 mol / L citric acid was added, and 12 ml of 10% H2O2 was added. After 1 h of deposition by circulating the aqueous solution, Ce deposited Incoloy 800 alloy tube was obtained. Subsequently, it was treated at a temperature of 500°C under a high-purity hydrogen atmosphere for 2 h, forming a 100 nm thick layer of Ce dopant on the reactor contact surface, and then naturally cooled, obtaining Ce Incoloy 800 metal catalytic reactor, with Ce doping amount of 0.8 wt.%.

[0092] Example 14

[0093] Conversion deposition precipitation method

[0094] GH4169 alloy tube (id 14 od 18) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, then treated at 300°C for 2 h in a continuous flow of 200 ml / min N2atmosphere. A mixed aqueous solution of 10% Ce(NO3)2and 20% Fe(NO3)3was prepared in 2 L, 20 ml of 0.1 mol / L citric acid was added, and 22 ml of 10% H2O2was added. After 1 h of aqueous solution circulation deposition, the Ce-deposited GH4169 alloy tube was obtained. Subsequently, it was treated at 500°C in a high-purity hydrogen atmosphere for 2 h, forming a 100 nm thick layer of Ce and Fe dopant on the reactor contact surface, and then naturally cooled to obtain Ce-Fe GH4169 metal catalytic reactor, in which the doping amounts of Ce and Fe were 1.2 wt.% and 1.1 wt.% respectively.

[0095] Example 15

[0096] Conversion deposition precipitation method

[0097] Incoloy 800 alloy tube (id 14 od 18) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, then treated at 300°C for 2 h in a continuous flow of 200 ml / min N2atmosphere. A mixed aqueous solution of 20% La(NO3)3, 15% Ce(NO3)3and 20% Fe(NO3)3was prepared in 2 L, 26 ml of 0.1 mol / L citric acid was added, and 22 ml of 10% H2O2was added. After 1.5 h of aqueous solution circulation deposition, the La, Ce and Fe-deposited Incoloy 800 alloy tube was obtained. Subsequently, it was treated at 500°C in a high-purity hydrogen atmosphere for 2 h, forming a 100 nm thick layer of La, Ce and Fe dopant on the reactor contact surface, and then naturally cooled to obtain La-Ce-Fe Incoloy 800 metal catalytic reactor, in which the doping amounts of La, Ce and Fe were 1.6 wt.%, 1.0 wt.% and 1.1 wt.% respectively.

[0098] Example 16

[0099] Conversion deposition precipitation method

[0100] Inconel 725 alloy tube (id 14 od 18) was selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, and then treated at 300°C for 2 h under continuous flow of 200 ml / min N2. A mixed aqueous solution of 20% Al(NO3)3, 15% Ce(NO3)3 and 20% Fe(NO3)3 was prepared in 2 L, 26 ml of 0.1 mol / L citric acid was added, and 22 ml of 10% H2O2 was added. After 1.5 h of circulation deposition of the aqueous solution, La, Ce and Fe-deposited Inconel 725 alloy tube was obtained. Subsequent treatment at 500°C under high-purity hydrogen atmosphere for 2 h formed a 140 nm thick layer of Al, Ce and Fe-doped material on the reactor contact surface, and then natural cooling was performed, i.e. Al-Ce-Fe Inconel 725 metal catalytic reactor, in which the doping amounts of Al, Ce and Fe were 1.4 wt.%, 1.1 wt.% and 1.4 wt.% respectively.

[0101] Example 17

[0102] Conversion deposition precipitation method

[0103] Inconel 718 alloy tube (id 21 od 25) was selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature, and then treated at 300°C for 2 h under continuous flow of 200 ml / min N2. A mixed aqueous solution of 20% Ni(NO3)2 and 15% Zn(NO3)2 was prepared in 2 L, 30 ml of 0.1 mol / L citric acid was added, and 50 ml of 10% H2O2 was added. After 1.5 h of circulation deposition of the aqueous solution, Ni and Zn-deposited Inconel 718 alloy tube was obtained. Subsequent treatment at 500°C under high-purity hydrogen atmosphere for 2 h formed a 130 nm thick layer of Ni and Zn-doped material on the reactor contact surface, and then natural cooling was performed, i.e. Ni-Zn Inconel 718 metal catalytic reactor, in which the doping amounts of Ni and Zn were 4.5 wt.% and 1.0 wt.% respectively.

[0104] Example 18

[0105] Conversion deposition precipitation method

[0106] Inconel 600 alloy tube (id 10 od 14) was selected and subjected to boiling in 15% NaOH solution for 1 h for deoiling. The tube was washed with distilled water and air dried at room temperature. The tube was then subjected to heat treatment at 300°C for 2 h under continuous flow of N2at 200 ml / min. A 2 L aqueous solution of 20% La(N03)3, 15% Ce(N03)3and 20% Fe(N03)3was prepared. To this solution, 26 ml of 0.1 M citric acid and 22 ml of 10% H202were added. The tube was subjected to cyclic deposition for 1.5 h in the aqueous solution to obtain La, Ce and Fe deposited Inconel 600 alloy tube. The tube was then subjected to heat treatment at 500°C under high purity hydrogen atmosphere for 2 h to form a 100 nm thick La, Ce and Fe dopant layer at the tube surface. The tube was then allowed to cool naturally to obtain La-Ce-Fe Inconel 600 metal catalytic reactor with La, Ce and Fe doping of 1.6 wt.%, 1.0 wt.% and 1.1 wt.% respectively.

[0107] Example 19

[0108] Conversion deposition precipitation method

[0109] GH600 alloy tube (id 10 od 14) was selected and subjected to boiling in 15% NaOH solution for 1 h for deoiling. The tube was washed with distilled water and air dried at room temperature. The tube was then subjected to heat treatment at 300°C for 2 h under continuous flow of N2at 200 ml / min. A 2 L aqueous solution of 20% Ni(N03)2and 15% Ce(N03)3was prepared. To this solution, 100 ml of 0.1 M citric acid and 40 ml of 10% H202were added. The tube was subjected to cyclic deposition for 2 h in the aqueous solution to obtain Ni and Ce deposited GH600 alloy tube. The tube was then subjected to heat treatment at 500°C under high purity hydrogen atmosphere for 2 h to form a 100 nm thick Ni and Ce dopant layer at the tube surface. The tube was then allowed to cool naturally to obtain Ni-Ce GH600 metal catalytic reactor with Ni and Ce doping of 8.5 wt.% and 2.0 wt.% respectively.

[0110] Example 20

[0111] Conversion deposition precipitation method

[0112] Hastelloy G-35 alloy tube (id 10 od 14) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and dried at room temperature, and then heated at 300°C for 2 h in a continuous flow of 200 ml / min N2atmosphere. A 2 L aqueous solution of 20% Ni(NO3)2and 25% Fe(NO3)3was prepared, 100 ml of 0.1 mol / L citric acid was added, and 35 ml of 10% H2O2was added. After 3 h of aqueous solution circulation deposition, the Ni and Fe deposited Hastelloy G-35 alloy tube was obtained. Subsequently, it was treated at a temperature of 500°C in a high-purity hydrogen atmosphere for 2 h, a 130 nm thick Ni and Fe dopant thin layer was formed on the reactor contact surface, and then it was naturally cooled, i.e. a Ni-Ce Hastelloy G-35 metal catalytic reactor, wherein the doping amounts of Ni and Fe are 8.5 wt.% and 7.8 wt.% respectively.

[0113] Example 21

[0114] Conversion deposition precipitation method

[0115] Monel 400 alloy tube (id 12 od 16) was selected and boiled in 15% NaOH solution for 1 h for deoiling, washed with distilled water and dried at room temperature, and then heated at 300°C for 2 h in a continuous flow of 200 ml / min N2atmosphere. A 2 L aqueous solution of 20% Ba(NO3)2and 15% Fe(NO3)3was prepared, 33 ml of 0.1 mol / L citric acid was added, and 40 ml of 10% H2O2was added. After 1.5 h of aqueous solution circulation deposition, the Ba and Fe deposited Monel 400 alloy tube was obtained. Subsequently, it was treated at a temperature of 500°C in a high-purity hydrogen atmosphere for 2 h, a 120 nm thick Ba and Fe dopant thin layer was formed on the reactor contact surface, and then it was naturally cooled, i.e. a Ba-Fe Monel 400 metal catalytic reactor, wherein the doping amounts of Ba and Fe are 2.2 wt.% and 3 wt.% respectively.

[0116] Example 22

[0117] Conversion deposition precipitation method

[0118] GH1015 alloy tube (id 10 od 14) was selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature. The tube was then subjected to heat treatment at 300°C for 2 h under continuous flow of 200 ml / min of N2 atmosphere. A 2 L aqueous solution of 15% Ni(NO3)2and 25% Mg(NO3)2was prepared and 45 ml of 0.1 mol / L citric acid and 45 ml of 10% H2O2were added. The aqueous solution was circulated for 3 h to obtain Ni and Mg deposited GH1015 alloy tube. The tube was then subjected to heat treatment at 500°C under high purity hydrogen atmosphere for 2 h to form a 120 nm thick layer of Ni and Mg dopant at the reactor interface, followed by natural cooling to obtain Ni-Mg GH1015 metal catalytic reactor with 5.2 wt.% and 4.6 wt.% of Ni and Mg doping, respectively.

[0119] Example 23

[0120] Conversion deposition precipitation method

[0121] Inconel 783 alloy tube (id 12 od 16) was selected and subjected to steaming in 15% NaOH solution for 1 h for deoiling, washed with distilled water and air dried at room temperature. The tube was then subjected to heat treatment at 300°C for 2 h under continuous flow of 200 ml / min of N2 atmosphere. A 2 L aqueous solution of 20% Ni(NO3)2, 10% Mn(NO3)2, 15% Fe(NO3)3and 10% Zn(NO3)2was prepared and 40 ml of 0.1 mol / L citric acid and 50 ml of 10% H2O2were added. The aqueous solution was circulated for 3 h to obtain Ni, Mn, Fe and Zn deposited Inconel 783 alloy tube. The tube was then subjected to heat treatment at 500°C under high purity hydrogen atmosphere for 2 h to form a 160 nm thick layer of Ni, Mn, Fe and Zn dopant at the reactor interface, followed by natural cooling to obtain Ni-Mn-Fe-Zn Inconel 783 metal catalytic reactor with 5 wt.%, 2.5 wt.%, 3 wt.% and 1.5 wt.% of Ni, Mn, Fe and Zn doping, respectively.

[0122] II. Direct catalytic reaction of methane to olefins, aromatics and hydrogen under continuous flow conditions

[0123] All the catalytic reactors described above were used directly without loading of catalyst.

[0124] All reaction examples were carried out in a continuous flow microreactor equipped with gas mass flow meters, gas deoxygenation and dehydration tubes and online product analysis chromatograph (the tail gas of the reactor was directly connected to the quantification valve of the chromatograph for periodic real-time sampling analysis). Except for special instructions, N2 in the reaction feed gas was used as the internal standard gas. The online product analysis used an Agilent 7890B gas chromatograph equipped with FID and TCD dual detectors, in which the FID detector was equipped with an HP-1 capillary column for analysis of low-carbon olefins, low-carbon alkanes and aromatic hydrocarbons; the TCD detector was equipped with a Hayesep D packed column for analysis of low-carbon olefins, low-carbon alkanes, methane, hydrogen and internal standard nitrogen. The methane conversion, carbon-hydrogen product selectivity and carbon deposition were calculated according to the carbon balance before and after the reaction, and the calculation formulas were as follows:

[0125] methane conversion,

[0126]

[0127] wherein, A CH4,TCD,outlet , the peak area of methane after reaction at the tail gas outlet of the TCD detector; A N2,TCD,outlet , the peak area of nitrogen after reaction at the tail gas outlet of the TCD detector; A CH4,TCD,RT , the peak area of methane at room temperature of the TCD detector; A N2,TCD,RT , the peak area of methane at room temperature of the TCD detector.

[0128] product and carbon deposition selectivity,

[0129]

[0130]

[0131]

[0132] wherein, total number of carbon atoms entering the reactor; relative correction factor of methane and nitrogen on the TCD detector; C x H y product selectivity; C x H y , x is the number of C, and y is the number of H; C x H y relative correction factor of product and benzene on the FID detector; peak area of the tail gas at the TCD detector after reaction; peak area of the tail gas at the FID detector after reaction;

[0133] The products in the following examples are all detectable by gas chromatography.

[0134] Comparative Example 2

[0135] A 1.6 meter blank without a doped metal active component was used A 5 g of 20-40 mesh 1.5 wt.% Ni-1.1 wt.% Co / SiO2 powder catalyst was added to an Inconel 601 metal reactor, and after the reactor was purged with 0.5 L / min Ar for about 30 minutes, the Ar flow rate was maintained and the reactor was programmed to increase in temperature at a rate of 6°C / min from room temperature to 1050°C, while adjusting the 90% CH4 / 10% N2 (volume content, hereinafter the same) to a flow rate of 2 L / min, and after maintaining for 30 minutes, on-line analysis was started, and then a 200 hour stability test was performed, and the reactor was blocked by carbon deposition and the reaction was stopped, and the analysis results showed that after 30 minutes, the methane conversion rate was 10%, the ethylene selectivity was 20%, the propylene selectivity was 5%, the benzene selectivity was 10%, the naphthalene selectivity was 5%, and the carbon deposition selectivity was 60%. After 200 hours, the methane conversion rate was reduced to 6%, and the reactor was blocked and the reaction was stopped.

[0136] Comparative Example 3

[0137] A 1.6 meter blank without a doped metal active component was used An Inconel 601 metal catalytic reactor was used, and after the reactor was purged with 0.5 L / min Ar for about 30 minutes, the Ar flow rate was maintained and the reactor was programmed to increase in temperature at a rate of 6°C / min from room temperature to 1050°C, while adjusting the 90% CH4 / 10% N2 (volume content, hereinafter the same) to a flow rate of 2 L / min, and the analysis results showed that the methane conversion rate was 5%, the ethylene selectivity was 28%, the benzene selectivity was 5%, the naphthalene selectivity was 6%, and the carbon deposition selectivity was 51%.

[0138] Application Example 1

[0139] A 1.6 meter Ru A GH3530 metal catalytic reactor (catalytic reactor preparation example 1) was used, and after the reactor was purged with 0.5 L / min Ar for about 30 minutes, the Ar flow rate was maintained and the reactor was programmed to increase in temperature at a rate of 6°C / min from room temperature to 950°C, while adjusting the 70% CH4 / 20% H2 / 10% N2 (volume content, hereinafter the same) to a flow rate of 2 L / min, and the analysis results showed that the methane conversion rate was 25%, the ethylene selectivity was 60%, the propylene selectivity was 15%, the benzene selectivity was 20%, the naphthalene selectivity was 5%, and the carbon deposition was zero.

[0140] Example 2

[0141] Using a 1.6 meter Ru-Fe A GH3030 metal catalytic reactor (catalytic reactor preparation example 2) was used, after replacing the air in the reactor with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 970°C at a rate of 6°C / min, while adjusting 70% CH4 / 20% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 3 L / min, the analysis results showed that the conversion rate of methane was 37%, the selectivity of ethylene was 68%, the selectivity of propylene was 15%, the selectivity of benzene was 10%, the selectivity of naphthalene was 6%, and the selectivity of carbon deposition was 1%.

[0142] Example 3

[0143] Using a 1.6 meter Ru-Fe A GH3030 metal catalytic reactor (catalytic reactor preparation example 2) was used, after replacing the air in the reactor with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 970°C at a rate of 6°C / min, while adjusting 70% CH4 / 20% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 3 L / min, the analysis results showed that the conversion rate of methane was 37%, the selectivity of ethylene was 68%, the selectivity of propylene was 15%, the selectivity of benzene was 10%, the selectivity of naphthalene was 6%, and the selectivity of carbon deposition was 1%.

[0144] Example 4

[0145] Using a 1.6 meter Ru-Fe A GH3030 metal catalytic reactor (catalytic reactor preparation example 2) was used, after replacing the air in the reactor with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 970°C at a rate of 6°C / min, while adjusting 70% CH4 / 20% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 3 L / min, the analysis results showed that the conversion rate of methane was 37%, the selectivity of ethylene was 68%, the selectivity of propylene was 15%, the selectivity of benzene was 10%, the selectivity of naphthalene was 6%, and the selectivity of carbon deposition was 1%.

[0146] Example 5

[0147] Using a 1.6 meter Ru-Fe Inconel 601 metal catalytic reactor (catalytic reactor preparation example 3), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise to 1050°C at a temperature rise rate of 6°C / min from room temperature, while adjusting 80% CH4 / 10% H2 / 10% N2 (volume content), the flow rate of the reaction raw material gas was 3 L / min, and the analysis results showed that the conversion rate of methane was 42%, the selectivity of ethylene was 68%, the selectivity of propylene was 11%, the selectivity of benzene was 18%, the selectivity of naphthalene was 3%, and there was no carbon deposition.

[0148] Application example 6

[0149] Using Ni-Co Inconel 601 metal catalytic reactor (catalytic reactor preparation example 4), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise to 1100°C at a temperature rise rate of 6°C / min from room temperature, while adjusting 70% CH4 / 20% H2 / 10% N2 (volume content, the same below), the flow rate of the reaction raw material gas was 6 L / min, and the analysis results showed that the conversion rate of methane was 58%, the selectivity of ethylene was 68%, the selectivity of propylene was 5%, the selectivity of benzene was 15%, the selectivity of naphthalene was 12.5%, and the selectivity of carbon deposition was 0.5%.

[0150] Application example 7

[0151] Using Ni-Co Inconel 601 metal catalytic reactor (catalytic reactor preparation example 4), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise to 1100°C at a temperature rise rate of 6°C / min from room temperature, while adjusting 60% CH4 / 30% H2 / 10% N2 (volume content), the flow rate of the reaction raw material gas was 9 L / min, and the analysis results showed that the conversion rate of methane was 52%, the selectivity of ethylene was 70%, the selectivity of propylene was 6%, the selectivity of benzene was 18%, the selectivity of naphthalene was 6%, and there was no carbon deposition.

[0152] Application examples (8-17)

[0153] Using 1.6 meters of Ru-Cu Inconel 600 metal catalytic reactor (catalytic reactor preparation example 5), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 1100 °C at a rate of 6 °C / min, while adjusting 45% CH4 / 50% H2 / 5% N2 (volume content), the flow rate of the reaction raw gas was 6 L / min, and the analysis results showed that the conversion rate of methane was 58%, the selectivity of ethylene was 68%, the selectivity of propylene was 5%, the selectivity of benzene was 15%, the selectivity of naphthalene was 12.5%, and the selectivity of carbon deposition was 0.5%.

[0154] Table 2

[0155]

[0156]

[0157] Application Example 18

[0158] Using 1.6 meters of Ni-Co Monel 400 metal catalytic reactor (catalytic reactor preparation example 7), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 1100 °C at a rate of 6 °C / min, while adjusting 70% CH4 / 20% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 6 L / min, and the analysis results showed that the conversion rate of methane was 58%, the selectivity of ethylene was 68%, the selectivity of propylene was 5%, the selectivity of benzene was 15%, the selectivity of naphthalene was 12.5%, and the selectivity of carbon deposition was 0.5%.

[0159] Application Example 19

[0160] Using 1.6 meters of Ni-Zn Inconel X-750 metal catalytic reactor (catalytic reactor preparation example 8), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 1050 °C at a rate of 6 °C / min, while adjusting 90% CH4 / 10% N2 (volume content), the flow rate of the reaction raw gas was 4 L / min, and the analysis results showed that the conversion rate of methane was 36%, the selectivity of ethylene was 55%, the selectivity of propylene was 10%, the selectivity of butene was 9%, the selectivity of benzene was 15%, the selectivity of naphthalene was 11%, and the selectivity of carbon deposition was 0.

[0161] Application Example 20

[0162] Using 1.6 meters of Ni-La Hastelloy G-30 metal catalytic reactor (catalytic reactor preparation example 9), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise from room temperature to 1020°C at a temperature rise rate of 6°C / min, while adjusting 80% CH4 / 10% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 3.6 L / min, and the analysis results showed that the conversion rate of methane was 41%, the selectivity of ethylene was 60%, the selectivity of propylene was 8%, the selectivity of butene was 10%, the selectivity of benzene was 20%, the selectivity of naphthalene was 2%, and zero carbon deposition.

[0163] Examples 21-31

[0164] 1.6-meter Ni-La Inconel 600 metal catalytic reactor (catalytic reactor preparation example 10), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise from room temperature to the following temperature at a temperature rise rate of 6°C / min, while adjusting 50% CH4 / 45% H2 / 5% N2 (volume content), the flow rate of the reaction raw gas was as follows, and the online analysis was started after 30 minutes of holding, and the analysis results showed the following table.

[0165] Table 3

[0166]

[0167]

[0168] Examples 32-42

[0169] 1.6-meter La-Ce-Fe Incoloy 800 metal catalytic reactor (catalytic reactor preparation example 15), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise from room temperature to the following temperature at a temperature rise rate of 6°C / min, while adjusting 45% CH4 / 50% H2 / 5% N2 (volume content), the flow rate of the reaction raw gas was as follows, and the online analysis was started after 30 minutes of holding, and the analysis results showed the following table.

[0170] Table 4

[0171]

[0172]

[0173] Example 43

[0174] 1.6-meter Ni-Zn Inconel 718 metal catalytic reactor (catalytic reactor preparation example 17), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise to 1060°C at a temperature rise rate of 6°C / min from room temperature, while adjusting 80% CH4 / 10% H2 / 10% N2 (volume content), the flow rate of the reaction raw gas was 9 L / min, and the analysis results showed that the conversion rate of methane was 44%, the selectivity of ethylene was 56%, the selectivity of propylene was 9%, the selectivity of butene was 10%, the selectivity of benzene was 20%, the selectivity of naphthalene was 4%, and the selectivity of carbon deposition was 1.0%.

[0175] Application Example 44

[0176] 1.6-meter La-Ce-Fe Inconel 600 metal catalytic reactor (catalytic reactor preparation example 18), after the reactor was replaced with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept unchanged, and the temperature was programmed to rise to 1150°C at a temperature rise rate of 6°C / min from room temperature, while adjusting 50% CH4 / 45% H2 / 5% N2 (volume content), the flow rate of the reaction raw gas was 20 L / min, and the analysis results showed that the conversion rate of methane was 70%, the selectivity of ethylene was 72%, the selectivity of propylene was 5%, the selectivity of butene was 5%, the selectivity of benzene was 16%, and the selectivity of naphthalene was 2%; after 500 hours of stability test, the analysis results showed that the conversion rate of methane was 68%, the selectivity of ethylene was 70%, the selectivity of propylene was 8%, the selectivity of butene was 6%, the selectivity of benzene was 12%, and the selectivity of naphthalene was 4%; after 1000 hours of stability test, the analysis results showed that the conversion rate of methane was 65%, the selectivity of ethylene was 67%, the selectivity of propylene was 6%, the selectivity of butene was 10%, the selectivity of benzene was 10%, the selectivity of naphthalene was 6.5%, and the selectivity of carbon deposition was 0.5%.

[0177] Application Example 45

[0178] 20-meter La-Ce-Fe An Inconel 600 metal catalytic reactor (Catalytic reactor preparation example 18) was used. After replacing the air in the reactor with 0.5 L / min Ar gas for about 30 minutes, the Ar flow rate was kept constant, and the temperature was programmed to rise from room temperature to 1100°C at a rate of 6°C / min, while adjusting the CH4 / H2 / N2 (volume content) to 70% and the feed gas flow rate to 22 L / min. A 110-hour stability test was conducted. The analysis results showed that the methane conversion rate was 61%, the ethylene selectivity was 70%, the propylene selectivity was 6%, the butene selectivity was 5%, the benzene selectivity was 16%, and the naphthalene selectivity was 3%.

[0179] Application Examples 46-47

[0180] Using 20 meters of Ni-Ce The GH600 metal catalytic reactor (Catalytic reactor preparation example 19) was used to replace the air in the reactor with 0.5 L / min Ar gas for about 30 minutes. After keeping the Ar flow rate constant, the temperature was increased from room temperature to the following temperature at a heating rate of 6℃ / min. At the same time, the flow rates of the 60% CH4 / 35% H2 / 5% N2 reaction feed gas were adjusted as follows. After holding for 30 minutes, online analysis was started. The analysis results are shown in the table below.

[0181] Table 5

[0182]

[0183] In summary, this invention utilizes a catalytic reactor with a reaction temperature of 900-1200℃, a reaction pressure of atmospheric pressure, and a feed gas flow rate of 1-100 L / min. The methane conversion rate is 25-80%, the olefin selectivity is 60-90%, the aromatics selectivity is 0-20%, and there is zero carbon deposition.

[0184] Therefore, it can be concluded that the catalyst of the catalytic reactor of the present invention has the characteristics of long life (>1000h), high product selectivity, zero carbon deposition, easy product separation, good process repeatability, and safe and reliable operation, and has broad prospects for industrial application.

[0185] It should be noted that, according to the above embodiments of the present invention, those skilled in the art can fully realize the scope of the independent claims and dependent claims of the present invention, and the implementation process and method are the same as those in the above embodiments; and the parts of the present invention not described in detail belong to the well-known technology in the art.

[0186] The above merely illustrates some specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A process for the catalytic conversion of methane to olefins, aromatics and hydrogen under oxygen-free conditions, characterized in that: The metal catalytic reactor is used for reaction, and methane is directly catalytically converted into olefins, aromatic hydrocarbons and hydrogen; The metal catalytic reactor comprises a metal pipe and a catalyst active component, the catalyst active component is coated on a contact surface of the metal pipe and a reaction raw material, a catalytic dopant thin layer is formed on the contact surface of the metal pipe and the reaction raw material, the catalyst active component and a base metal of the contact surface of the metal pipe form a catalyst, and the contact surface refers to an inner wall and / or an outer wall of the metal pipe. The metal catalytic reactor is prepared by the following method: An electrochemical deposition method comprises the following steps: (1) The base pipe is boiled in a 10-20 wt.% NaOH or KOH solution for 1-2 h for oil removal treatment, and then washed and dried at room temperature for standby; (2) The base pipe after the treatment in step (1) is heated in a hot N2 atmosphere, the heating temperature is 300-500 ℃, and the heating time is 1-2 h, so as to form a corrosion-resistant conductive thin film layer; (3) At room temperature, a water solution or an organic solution of a doped metal element precursor is prepared, the pH value of the solution is adjusted to 3.3-6.5, the metal pipe to be doped is immersed in the doped metal element precursor solution, a power supply is connected and used as a cathode, platinum is used as an anode, the distance between the cathode and the anode is adjusted to 2-5 cm after the circuit is connected, a direct current stabilized power supply is adjusted, a constant current mode is maintained, the current is 5 mA-0.5 A, and the electrochemical deposition is performed for 0.5-2 h, then the metal catalytic reactor is obtained after the deposition is completed and the metal pipe is washed with deionized water and dried. Or a conversion deposition and precipitation method comprises the following steps: (1) The base pipe is boiled in a 10-20 wt.% NaOH or KOH solution for 1-2 h for oil removal treatment, and then washed and dried at room temperature for standby; (2) The base pipe after the treatment in step (1) is heated in a hot N2 atmosphere, the heating temperature is 300-500 ℃, and the heating time is 1-2 h, so as to form a corrosion-resistant conductive thin film layer; (3) At room temperature, a water solution or an organic solution of a doped metal element precursor is prepared, the pH value of the solution is adjusted to 3.8-7.2, the metal pipe to be doped is immersed in the doped metal element precursor solution, the solution is in a flowing state in the metal pipe to be deposited, then a 10-20 wt.% H2O2 aqueous solution is added for conversion deposition and precipitation, the deposition time is 0.5-5 h, and the metal catalytic reactor is obtained after the deposition is completed.

2. The method of claim 1, wherein: The thickness of the catalytic dopant thin layer is 100 nm-1 mm.

3. The method of claim 1, wherein: The doping is lattice doping, the catalyst active component is a metal element or a mixture of a metal element and a non-metal element, and the doping amount of the metal element is 0.1-20 wt.% based on the total weight of the dopant thin layer.

4. The method of claim 3, wherein: The metal element exists in the form of one or more of an oxide, a carbide, a nitride, a silicide and an alloy, and the metal element comprises one or more of magnesium, aluminum, calcium, barium, titanium, manganese, vanadium, niobium, tungsten, molybdenum, chromium, iron, cobalt, nickel, copper, zinc, tin, gallium, zirconium, lanthanum, cerium, ruthenium, gold, palladium and platinum.

5. The method of claim 1, wherein: The doped metal element precursor used in the electrochemical deposition method is one or two or more of nitrate, soluble halide, soluble sulfate, soluble carbonate, soluble phosphate, soluble methanolate, soluble ethanolate, soluble formate, soluble acetate of metal; The doped metal element precursor used in the conversion deposition precipitation method is one or two or more of chloride, methanolate, ethanolate, formate, acetate of metal.

6. The method of claim 1, wherein: The catalytic reaction temperature is 750-1200℃; the flow rate of the reaction raw material gas is 1-100L / min.

7. The method of claim 1, wherein: The reaction raw material gas is methane or a mixture of methane and other gases; The other gases include one or both of inert atmosphere gases and non-inert atmosphere gases; The inert atmosphere gases are one or two or more of nitrogen, helium, neon, argon, krypton, and the volume content of the inert atmosphere gases in the reaction raw material gas is 0-95%; The non-inert atmosphere gases are one or two or more of a mixture of carbon monoxide, hydrogen, and C number 2-4 alkanes, and the volume content ratio of the non-inert atmosphere gases to methane is 0-50%; The volume content of methane in the reaction raw material gas is 5-100%.

8. The method of claim 1, wherein: The reaction process is a continuous flow reaction mode, and when the continuous reaction is performed, the reaction pressure is 0.05-1MPa.

9. The method of claim 1, wherein: The product of the aromatic hydrocarbon includes one or two or more of benzene, toluene, p-xylene, o-xylene, m-xylene, ethylbenzene, and naphthalene.

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