CN102553600B - Method for preparing methane from synthesis gas and coproducing low-carbon mixed alcohol - Google Patents

Abstract

A reaction catalyst for producing methane from syngas and co-producing low-carbon mixed alcohols, and a process for its preparation and methane synthesis and co-producing mixed alcohols. The catalyst composition is CuCoMAO/C or CuCoMAZnO/C, in which M is Zn, Cr, Fe, V, Mn, A is an alkali metal or alkaline earth metal additive, and C is a carrier, including aluminum oxide AL ₂ O ₃ , zirconia ZrO, silicon dioxide SiO ₂ , or titanium oxide TiO ₂ . The content of copper oxide is 1-90wt% of the total weight, the content of Co oxide is 1-95wt% of the total weight of the catalyst, the content of M oxide is 1-90wt% of the total weight of the catalyst, and the content of oxides of A is 1-90wt% of the total catalyst weight. 0.01 to 25% by weight. The preparation process of the catalyst adopts the impregnation method, and then roasts to obtain the oxidized catalyst. The raw material of the present invention is synthesis gas, which has a wide range of sources, and can be obtained from coal or biomass. The cost of the catalyst is low, the preparation is simple, the efficiency is high, the product can be adjusted as required, and the catalyst is suitable for continuous large-scale production.

Description

A method for producing methane from syngas and co-producing low-carbon mixed alcohols

technical field

The invention belongs to the field of catalytic chemistry, relates to the conversion of syngas to methane and the co-production of low-carbon mixed alcohols, and in particular provides a catalyst for synthesizing methane at medium and low temperatures and co-producing low-carbon mixed alcohols, the preparation of the catalyst and its application.

Background technique

With the implementation of the domestic sustainable development strategy and the strengthening of environmental protection policies, the domestic demand for natural gas has increased significantly. Domestic natural gas production cannot fully meet the market demand, and the contradiction between supply and demand is prominent. Therefore, it is necessary to expand resource supply through multiple channels and methods to meet the growing growing market demand. At the same time, based on the characteristics of my country's oil-scarce, gas-rich and coal-rich energy structure, the development of coal-to-natural gas is one of the feasible ways. In the process of coal conversion, the energy efficiency of coal-to-natural gas is the highest coal utilization method, reaching 53%, which can not only greatly reduce coal consumption, but also reduce SO ₂ and CO ₂ emissions and reduce environmental pollution. In addition, coal-to-natural gas can be transported on a large scale through pipelines, which increases the safety of its transportation and use.

Converting coal gas into methane (synthetic natural gas) is a mature technology. 1 ton of coal can be converted into 400m ³ synthetic natural gas. At present, mature processes include Topsoe Methanation Cycle Process (TREMPTM) technology, DAVY Company Methanation Technology (CRG ). BASF and Lurgi also have mature methanation technologies. China is relatively familiar with methanation technology.

At present, whether large-scale coal-to-methane production has good economic benefits has yet to be verified by actual production. The coal-to-methane industry has the characteristics of high investment and high risk. If coal-to-natural gas and other coal-based coal-to-gas co-productions can be realized, the anti-risk capability of coal-to-natural gas projects can be increased. Realizing the joint production of various coal-based products such as coal-based natural gas and coal-based methanol, coal-based olefins, coal-based oil, and synthetic ammonia will realize the complementary advantages of various coal-based products and effectively improve the economic benefits and overall efficiency of coal-based natural gas projects. The ability to resist risks. In addition, the gas consumption in cities in my country is very unbalanced. The northern region uses a lot of gas in winter, and the gas consumption in non-heating seasons is small, and the problem of peak regulation is very serious. In addition to using underground gas storage, gas peak-shaving power generation or LNG and other peak-shaving methods, coal-to-natural gas plants can also be used for peak shaving, that is to say, coal-to-natural gas plants produce natural gas in winter, and co-produce a part of methanol and oil in other seasons. , Olefins, low-carbon mixed alcohols, synthetic ammonia and other products.

The research and development of catalysts and processes for the synthesis of methane from coal through synthesis gas, parallel production of alcohol, oil, olefins, low-carbon mixed alcohols, and ammonia synthesis has great practicability and application prospects.

Contents of the invention

The object of the present invention is to provide a catalyst for producing methane from syngas and co-producing low-carbon mixed alcohols, its preparation technology and application.

In addition to the conversion of synthesis gas into methane, the present invention also co-produces some low-carbon mixed alcohols, while in the prior art, the synthesis gas is completely converted into methane, with the goal of complete conversion. This is the copper-cobalt-based catalyst provided by the invention and the current There is the biggest difference in technology.

The synthesis gas is reacted through a reactor equipped with a catalyst to prepare methane and co-produce low-carbon mixed alcohols; the catalyst composition is CuCoMA/C,

in:

The active component Cu, calculated as a metal element, has a content of 1.0-90.0wt% in the catalyst;

The active component Co, calculated as a metal element, has a content of 1.0-90.0wt% in the catalyst;

Component M is an additive, which is any one or a mixture of any of Zn, Cr, Fe, V, Mn, and its content in the catalyst is 0.0-90.0wt% in terms of metal elements;

Component A is an auxiliary agent, which is any one or a mixture of Li, Na, K, Mg, Ca, Sr, Ba, and its content in the catalyst is 0.0-25.0wt% in terms of metal elements;

The carrier component C is any one or a combination of Al ₂ O ₃ , ZrO, SiO ₂ , TiO ₂ , and its content in the catalyst is 10.0-95.0 wt%.

The present invention utilizes the above-mentioned catalyst to carry out the reaction of producing methane from syngas and co-producing low-carbon mixed alcohols. The reaction temperature T is 200≤T≤400°C, the reaction pressure P is 0.5≤P≤10.0MPa, and the reaction volume space velocity LHSV is 1000≤ LHSV≤40000h ^-1 .

The catalyst of the present invention is reduced with hydrogen, or hydrogen diluted with inert gas, or synthesis gas before the reaction, and then reacted.

The hydrogen to carbon monoxide ratio of the reaction raw material synthesis gas in the present invention is H ₂ /CO=2-8.

The content of the active component copper in the catalyst of the invention is 20.0-50.0wt% in terms of metal elements, and the content of cobalt in the catalyst is 5.0-20.0wt% in terms of metal elements.

The promoter M of the catalyst of the present invention is that the content of Mn and/or Fe in the catalyst is 1.0-15wt%.

The content of the auxiliary agent A in the catalyst of the present invention is 0.01-5.0wt%

The content of the promoter Zn in the catalyst of the present invention is 5.0-20.0 wt % in terms of metal elements.

The content of the carrier of the catalyst in the invention is 60.0-75wt%.

The preparation of catalyst of the present invention adopts impregnation method, and step is as follows:

a) According to the weight ratio of each component in the catalyst, the carrier component C is subjected to calcination and purification treatment at a temperature of 400-700° C. for 1-10 hours, and then cooled;

b) impregnating the sample obtained in step a) with an aqueous solution containing copper, cobalt, the metal ions of component A and component M in equal volume for 2 to 12 hours;

c) The impregnated sample obtained in step b) is evaporated to dryness at 60-90°C, dried at 100-150°C, and calcined at 400-800°C for 1-20 hours to obtain the catalyst.

The metals mentioned in the present invention are all quoted in the form of nitrates, which are prepared into an aqueous solution containing metal ions. The preparation of the aqueous solution of metal ions and the steps of impregnating the carrier can be carried out with reference to conventional techniques.

After the catalyst of the present invention is prepared, the reduction treatment shall be carried out according to the method of the present invention before being used for the reaction.

The carbon number n of the low-carbon mixed alcohol in the present invention is: 1≤n≤4, including methanol, ethanol, propanol, butanol and isobutanol.

The invention adopts cheap raw materials and a simple impregnation method to prepare a novel catalyst for partial methanation of synthesis gas and co-production of low-carbon mixed alcohols. Since synthesis gas can be obtained from coal gasification, it is possible to realize the co-production of coal-based natural gas and other coal chemical products, achieve the complementary advantages of various coal-based products, and effectively improve the economic benefits and overall risk resistance of coal-based natural gas projects Ability.

Description of drawings

Figure 1 shows the catalytic performance of copper-cobalt-based catalyst CuCoFeK/Al ₂ O ₃ for H ₂ /CO=2:1 synthesis gas methanation and co-production of low-carbon mixed alcohols at different reaction temperatures. (Catalyst quality: 1g CuCoFeK/Al ₂ O ₃ ; Feed gas composition: H ₂ /CO/Ar=64/32/4; Syngas flow rate: Syngas=60ml/min; Reaction pressure: P=5.0MPa; Activation conditions: 5h at 400℃)

Figure 2 shows the catalytic performance of copper-cobalt-based catalyst CuCoFeK/Al ₂ O ₃ for H ₂ /CO=3:1 synthesis gas methanation and co-production of low-carbon mixed alcohols at different reaction temperatures. (Catalyst quality: 1g CuCoFeK/Al ₂ O ₃ ; Feed gas composition: H ₂ /CO/Ar=72/24/4; Syngas flow rate: Syngas=60ml/min; Reaction pressure: P=4.0MPa; Activation conditions: 5h at 400℃)

Figure 3 shows the catalytic performance of copper-cobalt-based catalyst CuCoFeK/ZrO ₂ for H ₂ /CO=2:1 synthesis gas methanation and co-production of low-carbon mixed alcohols at different reaction temperatures. (Catalyst quality: 1g CuCoFeK/ZrO ₂ ; feed gas composition: H ₂ /CO/Ar=64/32/4; synthesis gas flow rate: Syngas=60ml/min; reaction pressure: P=5.0MPa; activation condition: 430°C next 5h)

Detailed ways

The preparation method of embodiment 1 catalyst

1.1 Catalyst preparation process

10 grams of gamma-alumina or zirconia carrier is impregnated with corresponding nitrates in a certain order, equal volume and step by step on the carrier C, and roasted at 400-800 ° C. During the reaction, use hydrogen, or hydrogen diluted with inert gas, or synthesis gas (mixed gas of _H2 and CO) to reduce, and then carry out the reaction.

1.2 Preparation _{of catalyst 30%CuO-10%CoO-1%Fe2O3-0.5 % K2O / Al2O3}

The 5.85g Al ₂ O ₃ carrier is subjected to roasting purification treatment at a temperature of 550°C. After cooling, an equal volume impregnation is performed. Dissolve 9.06g of Cu(NO ₃ ) ₃ ·3H ₂ O, 3.93g of Co(NO ₃ ) ₂ ·6H ₂ O, 0.054g of KNO ₃ and 0.51g of Fe(NO ₃ ) ₃ ·9H ₂ O in 5.0 ml of deionized water, and impregnate the mixed aqueous solution onto 5.85g of Al ₂ O ₃ carrier by equal-volume impregnation method, and evaporate the excess solvent in a water bath at 80°C. The obtained sample was dried in an oven at 120°C for 12 hours. After drying, the sample was placed in a muffle furnace, heated to 550°C at a heating rate of 2°C/min, and calcined for 5 hours to obtain a catalyst 30%CuO-10%CoO-1% _Fe2 O ₃ -0.5% K ₂ O/Al ₂ O ₃ .

The analytical method of embodiment 2 product

The obtained product was analyzed with Agilent 7890A. The chromatograph is equipped with dual detectors FID and TCD, and has a ten-way valve, which allows the products to enter the packed column and capillary column respectively at the same time. Data were processed with Agilent's Chemstation software.

The specific chromatographic conditions of Agilent are as follows:

Chromatography: Agilent 7890A

FID column: HP-PONA 19091S-001, 50mx0.2mm (inner diameter), 0.5μm film thickness

Carrier gas: helium, 2.5ml/min

Oven temperature: 35°C for 5 minutes

    35-150°C, 5°C/min

      150°C for 10 minutes

Inlet: Split (100:1) Temperature: 170°C

Detector: FID 250°C

TCD column: carbon molecular sieve column, TDX-01 2mx2mm (inner diameter)

Carrier gas: helium, 20ml/min

Oven temperature: 35°C for 5 minutes

    35-150°C, 5°C/min

    150°C for 10 minutes

Injection port: Temperature: 170°C

Detector: TCD 200°C

Example 3 Catalytic Reaction Performance of Syngas to Methane and Co-production of Low-carbon Mixed Alcohols

In a tubular fixed-bed reactor, the prepared catalyst was tested and evaluated for the catalytic reaction performance of synthesis gas to methane and co-production of low-carbon mixed alcohols. According to the requirements of the present invention, the process of producing methane from syngas and co-producing low-carbon mixed alcohols is set as follows:

Raw material composition: H2/CO/Ar Argon (Ar) as internal standard

Reaction pressure: 3.0MPa or 5.0MPa

Catalyst weight: 1.0g

Catalyst particle size: 40-60 mesh

Catalyst bed height: ~10mm

At the beginning of the investigation, the catalyst was first reduced for 5 hours at 4500°C under the condition of pure hydrogen, or diluent gas, or synthesis gas, and then the temperature of the bed was lowered to the specified temperature, and the synthesis gas was introduced to react. The reactor is heated by an electric furnace, and the reaction temperature is controlled by a thermocouple inserted into the catalyst bed. The composition of feed gas and product gas is detected by Angilent7890 gas chromatograph, which has two detectors: hydrogen flame detector and thermal conductivity detector. The hydrogen flame detector detects the distribution of hydrocarbons in the product, and the thermal conductivity detector detects hydrogen, carbon monoxide, carbon dioxide, methane and internal standard argon in the raw material and product. The composition of the two detectors is integrated with methane as an intermediary. Unless otherwise stated, the following examples of the present invention were carried out under the above-mentioned experimental conditions.

Because the experiment is carried out under different reaction conditions, the selectivity of the low-carbon mixed alcohols obtained is also different, and the products can be adjusted as required. The carbon number n of the low-carbon mixed alcohol obtained here is: 1≤n≤4, including methanol, ethanol, propanol, butanol and its isomers. The results are shown in FIGS. 1 to 3 .

Claims (9)

1. for the synthesis of a catalyst for gas methane processed coproduction MAS, it is characterized in that, catalyst consists of CuCoMA/C,

Wherein:

Active component Cu, in metallic element, the content in catalyst is 1.0-90.0wt%;

Active component Co, in metallic element, the content in catalyst is 1.0-90.0wt%;

Component M is auxiliary agent, and for any one or a few mixing in Zn, Cr, Fe, V, Mn, in metallic element, the content that its content in catalyst is 0.0-90.0wt% and M is not 0.0wt%;

Component A is auxiliary agent, is any one or a few mixing in Li, Na, K, Mg, Ca, Sr, Ba, and in metallic element, its content in catalyst is 0.01-5.0wt%;

Carrier component C is Al ₂o ₃, ZrO, SiO ₂, TiO ₂in any one or a few combination, its content in catalyst is 10.0-95.0wt%,

The content sum of all components is 100wt%.

2. according to catalyst claimed in claim 1, it is characterized in that, the content of described active ingredient copper in catalyst is 20.0-50.0wt%, and the content of cobalt in catalyst is 5.0-20.0wt%.

3. according to catalyst claimed in claim 1, it is characterized in that, the auxiliary agent M of described catalyst is that the content in catalyst is 1.0-15wt% taking metallic element for Mn and/or Fe.

4. according to catalyst claimed in claim 1, it is characterized in that, taking metallic element, the content in catalyst is 5.0～20.0wt% to described Zn.

5. according to catalyst claimed in claim 1, it is characterized in that, the content of described carrier in catalyst is 60.0-75wt%.

6. a preparation method for catalyst described in claim 1, is characterized in that, described employing infusion process, and step is as follows:

A) by the weight ratio of each component in described catalyst, carrier component C is carried out in the temperature of 400～700 DEG C after 1～10 hour roasting purified treatment, cooling;

B) with the aqueous solution that contains copper, cobalt, described component A and component M metal ion, step a) gained sample is carried out to incipient impregnation, flood 2～12 hours;

C) by dry through 70～90 DEG C of evaporates to dryness, 100～150 DEG C the sample after step b) gained dipping, 400-800 DEG C roasting 1～20 hour, with hydrogen, or the hydrogen of inert gas dilution, or synthesis gas reduction, obtain described catalyst.

7. a method for preparing methane by synthetic gas coproduction MAS, is characterized in that, synthesis gas, by the reactor reaction of catalyst described in claim 1 is housed, is prepared to methane coproduction MAS; The reaction temperature T of described preparing methane by synthetic gas coproduction MAS is 200≤T≤400 DEG C, and reaction pressure P is 0.5≤P≤10.0MPa, and reaction volume air speed LHSV is 1000≤LHSV≤40000h ^-1.

8. in accordance with the method for claim 7, it is characterized in that, before described catalyst reaction, use hydrogen, or the hydrogen of inert gas dilution, or synthesis gas reduction, then reacting, the hydrogen of described reaction raw materials synthesis gas and carbon monoxide are than being H ₂/ CO=2-8.

9. in accordance with the method for claim 7, the carbon number n of described MAS is: 1≤n≤4, comprise methyl alcohol, ethanol, propyl alcohol, butanols, isobutanol.

Images