Ni-perovskite catalyst for the production of syngas by reforming of coke oven gas with co2

Abstract

The application discloses a reforming catalyst with multi-type ABO3 perovskite as a carrier and Ni as an active component, and the catalyst is subjected to reduction-weak oxidation section pretreatment to obtain a surface layer NiO x , a body phase zero-valence Ni bifunctional active site. SrTiNbO3, SrTiO3 and other series of perovskites can generate abundant reversible lattice oxygen vacancies, and cooperates with NiO x to synchronously activate CH4, CO2 and water vapor, and has the dual catalytic functions of methane dry reforming and steam reforming, and can inhibit carbon deposition and Ni sintering at high temperature. The catalyst has a Ni loading of 1-10 wt%, the carrier can be a single or composite perovskite, and the catalyst can be prepared through two routes of impregnation and coprecipitation. The H2 / CO molar ratio of the synthesis gas can be stably controlled in the range of 0.8-2.2 by adjusting the raw material ratio; the catalyst can continuously run for more than 1000 hours, the CH4 conversion rate is greater than or equal to 90%, and the CO2 conversion rate is greater than or equal to 90%. The catalyst uses cheap Ni to replace noble metal, the carrier can be selected from a wide range, has the dual values of coking byproduct gas resourceization and CO2 capture and utilization, and has low production cost and excellent anti-carbon deposition stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of coal chemical industry and CO2 capture and utilization (CCU) catalytic conversion, and specifically relates to a preparation process of a multi-type perovskite supported Ni-based catalyst and application of the catalyst in the preparation of synthesis gas with adjustable hydrogen-carbon ratio through the coupling of CO2 and steam reforming of surplus coking oven gas. BACKGROUND

[0002] The total amount of coal consumption in China is more than 4 billion tons per year, and the coal consumption of the coking industry is about 660 million tons per year, and the total amount of by-product coking oven gas is about 200 billion cubic meters; the coking device itself consumes about 50%, and the surplus coking oven gas is more than 100 billion cubic meters per year. The main components of the purified coking oven gas mainly include H2, CH4 and a small amount of low-carbon alkanes, which are high-quality raw materials for preparing synthesis gas, and direct venting or low-value combustion will cause serious resource waste and air pollution. At the same time, the metallurgical, thermal power and chemical industries emit a large amount of CO2 every year, and the methane dry reforming and steam coupling reforming are the core routes for simultaneous conversion of CH4 and CO2 and carbon emission reduction.

[0003] The existing industrial coking oven gas synthesis gas only adopts a single steam reforming process, which has four inherent defects: (1) the conventional steam reforming catalyst has very weak CO2 dissociation and activation ability, and the CO2 in the raw material cannot fully participate in the reforming reaction, so that the residual amount of CO2 in the product synthesis gas is high; when used for methanol synthesis, it will reduce the catalytic reaction rate and increase the water content of the crude methanol, and the downstream process has poor adaptability; (2) the traditional Ni-based catalyst mainly uses Al2O3, MgO and other ordinary oxide carriers, and the lattice oxygen is scarce, so that the Ni particles are easy to migrate, agglomerate and sinter at high temperature, and a large amount of filamentous coke is generated by CH4 cracking, so that the catalyst activity is greatly attenuated in a short period, and the catalyst needs to be regenerated frequently, which has high operation and maintenance cost; (3) the noble metal Ru, Ir and Pt type reforming catalyst has excellent catalytic performance, but the market price of noble metals is high, and the investment threshold for large-scale industrial application is extremely high, so it is difficult to popularize; (4) the existing Ni-based catalyst only uses a single impregnation process to load the metal, and the metal dispersion is limited, and there is no co-precipitation doping route to choose, so the metal-support interaction cannot be further strengthened; the carrier only uses a single oxide, and lacks a multi-perovskite composite carrier system, so that the high-temperature resistance and anti-coking performance are limited.

[0004] The nickel-based reforming catalysts disclosed in the existing patents CN113000059A and CN113332985A both use zero-valent Ni as the only active center, and do not construct a stable NiO xThe partial oxidation active site is supported by conventional alumina, and the problems of high-temperature carbon deposition and sintering are prominent; the existing perovskite reforming catalyst only selects single strontium titanate, does not expand SrTiNbO3 and La-based multi-component perovskite composite carrier, and only uses a single impregnation preparation route, which cannot balance high metal dispersion and low-cost mass production; the traditional industry cognition believes that only zero-valent metal has activity in the reforming reaction, and ignores the synergistic catalytic effect of surface partial oxidation metal and lattice oxygen vacancy, so that the conversion efficiency of CH4 and CO2 is low under medium and low temperature conditions. SUMMARY

[0005] 1. Technical problems to be solved by the present application

[0006] (1) Overcoming the defects of traditional single steam reforming catalysts, such as weak CO2 activation ability and fixed hydrogen-carbon ratio of synthesis gas; (2) Solving the pain points of ordinary oxide-supported Ni catalysts, such as high-temperature sintering, serious carbon deposition and poor long-period stability; (3) Abandoning high-cost noble metal catalytic systems and using inexpensive metal Ni to reduce industrial raw material input; (4) Providing two flexible switching nickel-loaded processes, i.e. impregnation and co-precipitation, and realizing Ni lattice doping by co-precipitation method to strengthen metal-support interaction; (5) Expanding a variety of high-temperature-resistant ABO3 perovskite single / composite carrier systems, relying on the reversible lattice oxygen vacancy of the carrier to synergize with NiO x Dual-site synchronous activation of CH4, CO2 and H2O to realize efficient coupling reforming of coke oven gas and output synthesis gas with adjustable wide-range hydrogen-carbon ratio.

[0007] 2. Complete technical solution

[0008] (1) Catalyst component system

[0009] One or more complex ABO3 perovskites are used as carriers, and metal Ni is the only active component without noble metals or other transition metals; after segmented reduction and selective weak oxidation pretreatment, Ni particles form zero-valent metal core + surface NiO x Partial oxidation thin-layer dual-function composite active structure. Component mass range: perovskite carrier 90-99 wt%, metal Ni active component 1-10 wt%; optional perovskite carriers: SrTiNbO3, SrTiO3, LaAlO3, LaFeO3, LaMnO3, La0.9Sr0.1NiO3, BaTiO3, SrZrO3; which can be used singly or in any proportion for solid-phase compounding.

[0010] (2) Complete preparation process of dual routes

[0011] Step 1: Single / Composite Perovskite Carrier Preparation

[0012] ① Single pure phase perovskite: select the corresponding metal nitrate, alkali salt raw material is dissolved in deionized water, ammonia water to adjust pH to 9-11, into the hydrothermal reactor 160-220 ℃ for 10-24 h; cooling, washing, drying, 800-1000 ℃ calcination 6-12 h, get pure phase perovskite powder; ② Composite perovskite carrier: two or more single perovskite powder according to the demand ratio, 300-500 r / min ball milling 2-6 h, 700-900 ℃ solid phase calcination 3-8 h, get multi-component composite perovskite.

[0013] Step 2: two kinds of Ni loading process

[0014] Scheme A: impregnation method (adapt to 1-5 wt% low Ni loading, simple process, low cost of mass production) dry perovskite powder and a certain amount of aqueous nickel nitrate solution are mixed, 60 ℃ constant temperature stirring evaporation to no free water, Ni salt is evenly adsorbed on the surface of the carrier pore, get impregnated precursor.

[0015] Scheme B: co-precipitation method (adapt to 5-10 wt% medium-high Ni loading, Ni lattice doping, stronger metal-carrier interaction) all metal precursor salt required for the preparation of perovskite, nickel nitrate hexahydrate is dissolved in deionized water, 30-80 ℃ constant temperature stirring; slowly add sodium carbonate / ammonium carbonate precipitator, control pH=8-11 throughout the process to complete synchronous co-precipitation; precipitate product constant temperature aging 1-6 h, water washing to no nitrate, 60-120 ℃ drying 8-24 h, get composite precursor of Ni evenly embedded in perovskite framework.

[0016] Step 3: precursor high temperature calcination

[0017] The solid precursor obtained in step 2 is placed in a muffle furnace, heated to 400-700 ℃ at a rate of 2-5 ℃ / min, and kept for 2-5 h to completely decompose the nitrate and carbonate, generating nickel oxide loaded intermediate.

[0018] Step 4: tube furnace staged reduction-weak oxidation pretreatment (core innovation step)

[0019] ① Reduction section: load the calcined powder, pass in 80-120 mL / min pure H2 or CO, 400-800 ℃ for 2-6 h, all the nickel oxide is reduced to zero-valent Ni nanoparticles; ② Weak oxidation section: switch to pure CO2 or water vapor carrier gas, maintain the flow rate at 80-120 mL / min, 600-1200 ℃ for 1-4 h; only the surface layer of Ni particles is selectively and partially oxidized to form stable NiO xActive layer, zero-valent metal Ni is reserved inside the particle.

[0020] (3) Coke oven gas reforming application process

[0021] The catalyst powder after pretreatment is pressed into tablets, crushed, and sieved into 40-60 mesh particles, mixed with quartz sand at a ratio of 1:1, and then loaded into a quartz fixed bed reactor after dilution; the raw gas is mixed in three ways: purified industrial coke oven gas, CO2, and water vapor; the reaction control parameters are temperature 800-1500 DEG C, system pressure 0.1-2.5 MPa; the control logic is that increasing the CO2 inlet amount and reducing the water vapor can reduce the H2 / CO ratio of the synthesis gas; increasing the water vapor and reducing the CO2 inlet amount can increase the H2 / CO ratio, and the adjustment range is stable at 0.8-2.2, which is suitable for Fischer-Tropsch synthesis (H2 / CO is about 0.8-1.6), methanol synthesis (H2 / CO is about 2.0-2.2), and other processes.

[0022] (4) Catalytic reaction mechanism

[0023] 1. Perovskite lattice oxygen vacancy anti-coking mechanism: SrTiNbO3, La series, etc. There are reversible variable valence metal ions (Nb 5+ / Nb 4+ , Fe³ + / Fe² + , Mn³ + / Mn² + ) inside the perovskite, which continuously generates a large number of lattice oxygen vacancies; vacancies can quickly capture and dissociate CO2 to produce active lattice oxygen, directly oxidize carbon intermediates produced by CH4 cracking, and inhibit the generation of carbon deposits from the source; 2. NiO x and zero-valent Ni cooperative activation mechanism: the surface NiO x has strong C-H bond breaking ability, which greatly reduces the activation energy of methane dissociation; the bulk zero-valent Ni maintains the channel for H atom desorption to generate H2, and the two cooperate to simultaneously complete the triple molecular activation of CH4, CO2, and H2O, and simultaneously catalyze dry reforming and steam reforming; 3. Strong metal-support anti-sintering mechanism: the co-precipitation process makes Ni embedded in the interstitial space of the perovskite lattice, and the impregnation method makes Ni uniformly adsorbed on the defect sites of the carrier, both of which form a strong metal-support interaction, limiting the migration and agglomeration of Ni atoms at high temperatures, and greatly extending the service life of the catalyst.

[0024] (Four) Advantages of the present application

[0025] 1. Raw material costs are significantly reduced, and there is no precious metal system. This invention uses only the inexpensive metal Ni as the sole active component, completely abandoning the high-priced precious metals Ru, Ir, and Pt. The perovskite raw material is a conventional industrial metal salt, with low procurement costs. Compared with precious metal catalysts, the cost of raw materials per ton is reduced by more than 90%.

[0026] 2. Dual preparation processes to adapt to different industrial production needs: The impregnation method is simple to operate and has low energy consumption, making it suitable for large-scale continuous production with low Ni loading of 1-5 wt%. The co-precipitation method achieves Ni lattice doping, resulting in higher metal dispersion and stronger metal-carrier interaction. It is suitable for high loading of 5-10 wt% and ultra-long-term stable operating conditions. The factory can flexibly switch the preparation route according to downstream needs.

[0027] 3. The multi-perovskite carrier system exhibits excellent high-temperature resistance and anti-carbon deposition properties. Conventional Al2O3 and MgO carriers are prone to phase transformation at high temperatures and lack oxygen vacancies. The ABO3 perovskite crystal structure of this invention has extremely strong thermal stability, with no structural collapse at high temperatures of 800–1500 ℃. The reversible lattice oxygen vacancies continuously eliminate carbon deposition, and no obvious carbon deposition is observed after 100 h of long-term operation.

[0028] 4. All-new NiO x With dual active sites and high conversion efficiency, it breaks the industry's conventional wisdom that only zero-valent Ni possesses catalytic activity; the surface NiO... x Synergistic activation of three types of reactant molecules by oxygen vacancies in the lattice; CH4 conversion rate ≥90% and CO2 conversion rate ≥91% under standard coke oven gas conditions, which is far superior to ordinary alumina-supported Ni catalyst.

[0029] 5. The syngas hydrogen-to-carbon ratio is adjustable over a wide range and is highly versatile. By finely adjusting the flow rate, temperature and pressure of the three feedstock inlets, the syngas H2 / CO ratio can be controlled within the full range of 0.8 to 2.2. One set of catalysts can simultaneously supply multiple downstream production lines of methanol, Fischer-Tropsch, and ethylene glycol, resulting in a high equipment reuse rate.

[0030] 6. Green preparation process, easy to scale up to industrial use. No highly toxic organic solvents such as toluene and cyclohexane are used throughout the process. Hydrothermal treatment, impregnation, calcination and tubular pretreatment are all general chemical equipment. The process route is continuous and adaptable. It simultaneously consumes coking waste gas and industrial CO2 emissions, combining carbon emission reduction and environmental benefits with the high added value of syngas.

[0031] 7. Long-term stability and low operation and maintenance costs: Strong metal-carrier interaction inhibits Ni high-temperature sintering. The activity decay is less than 6% after 100 hours of continuous operation, eliminating the need for frequent shutdowns for regeneration and reducing equipment start-up and shutdown losses and manual operation and maintenance costs. Attached Figure Description

[0032] Figure 1A N2 adsorption-desorption isotherm diagram of the perovskite carrier provided by the embodiment of the present application is shown in the figure; Figure 2 A catalyst stability test diagram of the coke oven gas reforming under different reaction conditions provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0033] Example 1

[0034] Preparation of 5 wt% NiO by impregnation method x / SrTiNbO3 catalyst

[0035] 1. Preparation of pure phase SrTiNbO3 carrier Weigh strontium nitrate, tetrabutyl titanate and niobium pentachloride, and dissolve them in deionized water. Ammonia water is used to adjust the pH value of the mixed solution to 10. The solution is transferred into a hydrothermal kettle and kept at 180 DEG C for 16 hours. After cooling, the solution is filtered and washed with deionized water. The solution is dried at 110 DEG C. The solution is calcined in a muffle furnace at 900 DEG C for 10 hours to obtain high specific surface area SrTiNbO3 perovskite powder.

[0036] 2. Preparation of impregnated precursor 10 g of dry SrTiNbO3 powder is taken, and 50 mL of deionized water solution containing 1.24 g of nickel nitrate hexahydrate is added. The solution is stirred at a constant temperature of 60 DEG C for 6 hours until the water is completely evaporated. The theoretical Ni loading is 5 wt%.

[0037] 3. High temperature calcination The solution is calcined in a muffle furnace at 500 DEG C for 3 hours at a heating rate of 3 DEG C / min. The nickel nitrate is completely decomposed into nickel oxide.

[0038] 4. Stepwise pretreatment 100 mL / min of H2 is introduced into a tubular furnace, and the solution is reduced at 700 DEG C for 3 hours. The carrier gas is switched to saturated water vapor, and the solution is weakly oxidized at 1200 DEG C for 0.5 hours to obtain NiO x Surface layer modified target catalyst.

[0039] 5. Coke oven gas reforming performance test 1 g of catalyst is pressed into a tablet and sieved to 40-60 mesh. The tablet is mixed with 1 g of quartz sand and packed into a fixed bed. The gas flow rate is 430 mL / min of coke oven gas, 90 mL / min of CO2 and 30 mL / min of water vapor. The reaction conditions are 850 DEG C and 0.1 MPa. The test results are as follows: the synthesis gas H2 / CO is about 2.2, the average CH4 conversion rate is 92.3%, the average CO2 conversion rate is 93.0%, and there is no obvious Ni agglomeration or carbon deposition on the catalyst after the reaction.

[0040] Example 2

[0041] Preparation of 8 wt% NiO by impregnation method x / SrTiO3 catalyst

[0042] 1. Preparation of SrTiO3 support: hydrothermal treatment at pH 9.5, holding at 200 ℃ for 12 h, and calcining at 850 ℃ for 8 h; 2. Impregnation solution: 1.98 g of nickel nitrate hexahydrate is dissolved in 50 mL of water, and 10 g of SrTiO3 powder is stirred and evaporated to dryness at 60 ℃, with a Ni loading of 8 wt%. 3. Calcination at 500 ℃ for 3 hours; 4. Pretreatment: H2 reduction at 750 ℃ ​​for 2 h, CO2 weak oxidation at 850 ℃ for 0.5 h; 5. Reforming conditions: 430 mL / min coke oven gas, 100 mL / min CO2, 15 mL / min steam, 1200℃, 1.7 MPa; syngas H2 / CO≈1.6, stable operation for 100 h, CH4 conversion rate 91.5%, CO2 conversion rate 92.1%.

[0043] Example 3

[0044] Preparation of 2 wt% NiO by impregnation method x / LaFeO3 catalyst

[0045] 1. Hydrothermal synthesis of LaFeO3: pH=11, heat treatment at 160 ℃ for 24 h, calcination at 800 ℃ for 12 h; 2. 0.48 g of nickel nitrate was added to prepare 50 mL of impregnation solution, with a theoretical Ni loading of 2 wt%. 3. Calcination at 500 ℃ for 3 h; reduction with H2 at 700 ℃ for 3 h; weak oxidation with CO2 at 750 ℃ ​​for 3 h; 3. Reaction conditions: 430 mL / min coke oven gas, 120 mL / min CO2, 5 mL / min steam, 850 ℃, 0.1 MPa; synthesis gas H2 / CO≈0.8, no significant decrease in activity after 100 h, CH4 conversion rate 90.2%, CO2 conversion rate 91.0%.

[0046] Example 4

[0047] Preparation of 5 wt% NiO by coprecipitation method x / SrTiNbO3 catalyst

[0048] 1. Preparation of coprecipitated composite precursor: Strontium nitrate, tetrabutyl titanate, niobium pentachloride, and nickel nitrate hexahydrate were all mixed and dissolved in deionized water and stirred at a constant temperature of 50 °C. Sodium carbonate precipitant was slowly added dropwise, and the pH was kept stable at 9.5 throughout the process. After precipitation was completed, the mixture was aged at a constant temperature of 50 °C for 4 h. The mixture was then filtered and washed with water until no nitrate ions were found in the filtrate, and dried at 110 °C for 16 h.

[0049] 2. Calcination treatment: Calcination in a muffle furnace at 500 ℃ for 3 h decomposes carbonates to obtain nickel oxide composite intermediates.

[0050] 3. Segmented pretreatment: H2 reduction at 700 ℃ for 3 h, CO2 weak oxidation at 800 ℃ for 2 h.

[0051] 4. The evaluation conditions for coke oven gas are completely consistent with those in Example 1; Test results: CH4 conversion rate 93.5%, CO2 conversion rate 94.1%, and the surface carbon content of the catalyst is much lower than that of the impregnation method sample under the same running time. Ni is uniformly dispersed and does not grow.

[0052] Example 5

[0053] Co-precipitation of 5 wt% Ni catalyst on a composite perovskite support (SrTiNbO3:SrTiO3=7:3)

[0054] 1. Prepare pure phase powders of SrTiNbO3 and SrTiO3 respectively, mix them at a mass ratio of 7:3, ball mill at 400 r / min for 4 h, and calcine them at 850 ℃ for 5 h to obtain a composite carrier; 2. Simultaneous doping of 5 wt% Ni was performed using the co-precipitation process described in Example 4; 3. The roasting and pretreatment parameters are the same as in Example 4; 4. Reforming test: At 850 ℃ and normal pressure, with H2 / CO≈2.1 in the synthesis gas, the CH4 conversion rate was 92.7% and the CO2 conversion rate was 93.5% after 100 h of operation, combining the advantages of both perovskite in resisting sintering and carbon deposition.

[0055] (vii) Comparative Example

[0056] A 5 wt% Ni catalyst was impregnated on a conventional γ-Al₂O₃ support. The preparation, pretreatment, and coke oven gas reforming evaluation conditions were identical to those in Example 1. Test results showed that the initial CH₄ conversion was only 74.6% at 850 °C and 0.1 MPa, with a 26% activity decrease after 120 h of operation. Electron microscopy revealed a large amount of filamentous carbon deposits on the catalyst surface, and significant agglomeration and growth of Ni particles, verifying the effectiveness of the multi-perovskite support and NiO₂ catalyst in this invention. x The unique advantages of active sites.

[0057] The above-described embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to help those skilled in the art understand the content of the present invention and implement it accordingly. The scope of this patent should not be limited to these embodiments alone. All equivalent changes or modifications made in accordance with the spirit disclosed in this invention still fall within the scope of this patent.

Claims

1. A Ni-perovskite catalyst, characterized in that, Mass fraction of each component based on the total mass of the catalyst: Perovskite support: 90–99 wt%; Active component: 1–10 wt%; The perovskite support is an ABO3-type composite oxide, selected from any one of SrTiNbO3, SrTiO3, LaAlO3, LaFeO3, LaMnO3, La0.9Sr0.1NiO3, BaTiO3, and SrZrO3, or a physical mixture / solid-phase composite mixture of two or more; After reduction-weak oxidation staged pretreatment, the bulk phase of the Ni particles is zero-valent Ni, and a stable partially oxidized NiO is formed on the particle surface. x NiO x It is the core active site for the reforming reaction.

2. The catalyst according to claim 1, characterized in that, All types of ABO3 perovskites can generate reversible lattice oxygen vacancies, synergistically with surface NiO. x Simultaneously activates methane, carbon dioxide, and water molecules, simultaneously catalyzes dry reforming and water vapor reforming, and oxidizes and eliminates carbon precursors in real time.

3. The catalyst according to claim 1, characterized in that, Ni nanoparticles are uniformly dispersed on the perovskite surface, and a strong metal-support interaction is formed between Ni and perovskite, which inhibits Ni migration, agglomeration, and sintering deactivation under high temperature conditions.

4. The catalyst according to claim 1, characterized in that, The composite perovskite carrier is prepared by ball milling two or more perovskite powders in any proportion and then solid-phase composite at 700-900 °C.

5. A method for preparing a Ni-perovskite catalyst, characterized in that, The process includes step 1, preparing a perovskite support; and step 2, loading Ni active components using either impregnation or co-precipitation methods, followed by uniform calcination and segmented pretreatment. Step 1: Prepare single perovskite powder using a hydrothermal method or a sol-gel method; composite perovskite is further subjected to ball milling and solid-phase calcination treatment; Step 2 (Choose one): Option A Impregnation method: Mix perovskite powder with nickel nitrate aqueous solution, stir at 60 ℃ until the water is completely evaporated to obtain the impregnation precursor; Option B: Co-precipitation method: Perovskite metal precursor salt and nickel salt are co-dissolved in water, and a precipitant is added dropwise under stirring to maintain a constant pH of 8-11 to complete co-precipitation. After aging, washing, and drying, a Ni-perovskite composite precursor is obtained; Step 3: High-temperature roasting in a muffle furnace decomposes the metal salt to obtain a nickel oxide intermediate; Step 4: Segmented pretreatment in a tubular furnace: First, high-temperature reduction is carried out by introducing H2 or CO, followed by weak oxidation by introducing CO2 or water vapor to generate NiO on the surface of Ni particles. x Active species.

6. The preparation method according to claim 5, characterized in that, Step 1: Hydrothermal conditions for single perovskite: pH=9-11 of metal salt mixture, hydrothermal temperature 160-220 ℃, holding temperature for 10-24 h; after drying the product, calcine at 800-1000 ℃ for 6-12 h; ball mill the composite perovskite powder for 2-6 h, and solid-phase calcine at 700-900 ℃ for 3-8 h.

7. The preparation method according to claim 5, characterized in that, Step 2 Scheme B Co-precipitation process parameters: The precipitant is sodium carbonate, ammonium carbonate or ammonia water; the precipitation temperature is 30-80 ℃, and the pH is controlled at 8-11; after precipitation, the mixture is aged at a constant temperature for 1-6 h, washed with water to remove impurities, and dried at 60-120 ℃ for 8-24 h.

8. The preparation method according to claim 5, characterized in that, Step 3: Calcination temperature 400-700 ℃, hold for 2-5 h.

9. The preparation method according to claim 5, characterized in that, Step 4: Reduction stage: Treat in H2 / CO atmosphere at 400–800 ℃ for 2–6 h, until nickel oxide is completely reduced to zero-valent Ni; Weak oxidation stage: Treat in CO2 / water vapor atmosphere at 600–900 ℃ for 1–4 h, until NiO is formed only on the surface of Ni. x The body phase remains at zero valence.

10. A method for using a catalyst in the production of syngas from coke oven gas coupled with CO2 and steam reforming, wherein the catalyst is the catalyst as described in any one of claims 1-4, characterized in that: The catalyst is compressed into tablets, crushed and screened into 40-60 mesh particles, and then loaded into a fixed-bed reactor. A mixture of purified coke oven gas, CO2, and steam is introduced into the reactor. The reaction temperature is 800-1500 ℃, and the system pressure is 0.1-2.5 MPa.

11. The application method according to claim 10, characterized in that, By adjusting the feed flow rates of coke oven gas, CO2, and steam, and by controlling the reaction temperature and pressure, the H2 / CO molar ratio of the produced syngas can be controlled within the range of 0.8 to 2.

2.

12. The application method according to claim 10, characterized in that, The catalyst operates continuously and stably for ≥100 h, with methane conversion rate ≥90% and CO2 conversion rate ≥91% within the system, and no obvious Ni sintering, carbon deposition, or deactivation.

Images