CN103084203A

CN103084203A - A kind of method that prepares CuZnAlFe series catalyst to catalyze CO2 add H2 to make dimethyl ether

Info

Publication number: CN103084203A
Application number: CN2011103362458A
Authority: CN
Inventors: 王明华; 黎潮; 王凤栾; 宫振宇; 翟玉春
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2011-10-31
Filing date: 2011-10-31
Publication date: 2013-05-08

Abstract

二氧化碳是主要的温室气体之一，对温室效应有着重要的影响。通过二氧化碳加氢合成二甲醚是控制二氧化碳的有效途径。采用水热法合成Cu-CuO-ZnO-Al₂O₃-Fe₂O₃催化剂(简称CZAF)，按质量比2∶1采用机械混合法制备加入HZSM-5的双功能催化剂；将原料气CO₂和H₂通入高压釜，4Mpa，260℃下，通过双功能催化剂的作用合成二甲醚，合成气通过气相色谱检测。结果表明：硝酸盐浓度为10％，老化温度为150℃，老化时间10h制备CZAF催化剂粒径最小，约200nm，比表面积达200.62m²/g，Fe含量对催化剂性质的影响不明显。在合成二甲醚的实验中，Fe含量为5％，反应时间为5h结果最佳，CO₂的转化率达21.5％和DME的选择性达33.3％。Carbon dioxide is one of the main greenhouse gases and has an important impact on the greenhouse effect. Synthesis of dimethyl ether by carbon dioxide hydrogenation is an effective way to control carbon dioxide. The Cu-CuO-ZnO-Al ₂ O ₃ -Fe ₂ O ₃ catalyst (referred to as CZAF) was synthesized by hydrothermal method, and the bifunctional catalyst was prepared by mechanical mixing method with HZSM-5 at a mass ratio of 2:1; the raw material gas CO ₂ and H ₂ into the autoclave, 4Mpa, 260 ° C, synthesize dimethyl ether through the action of a bifunctional catalyst, and the synthesis gas is detected by gas chromatography. The results show that: the concentration of nitrate is 10%, the aging temperature is 150℃, and the aging time is 10h. The particle size of CZAF catalyst is the smallest, about 200nm, and the specific surface area is 200.62m ² /g. The effect of Fe content on the properties of the catalyst is not obvious. In the experiment of synthesizing dimethyl ether, the Fe content is 5%, the reaction time is 5h, the result is the best, the conversion rate of _CO2 reaches 21.5% and the selectivity of DME reaches 33.3%.

Description

A kind of CuZnAlFe series catalyzer to catalyse CO for preparing 2Add H 2The method of preparing dimethy ether

Technical field

The present invention relates to industrial waste gas CO ₂The field that utilizes is specifically related to by synthetic CuZnAlFe catalyst CO ₂Add H ₂Generate the method for dimethyl ether.

Background technology

Carbon dioxide is one of main greenhouse gases, and greenhouse effects are had important impact.Along with the development of industry, airborne carbon dioxide content grows with each passing day, heavy damage the mankind's living environment, the comprehensive utilization of carbon dioxide has become the research in the urgent need to carrying out.Dimethyl ether is important organic chemical industry's product, is the important source material of many chemical products, is also the desirable alternative fuel of fossil fuel.No matter be from economy or the angle of environment, be all the effective way of controlling CO2 emission by the hydrogenation of carbon dioxide dimethyl ether synthesis.Patent 200810202014.6 (Mao Dongsen, Wang Song, Lu Guanzhong, Wang Rong, Wu Yan, Shanghai Institute Of Technology) the CuZnTiZr composite oxide catalysts catalysis hydrogenation of carbon dioxide of having reported for work prepares dimethyl ether, and carbon dioxide conversion reaches 28.6%, dimethyl ether selectively reaches 52.9%, and the yield of dimethyl ether reaches 15.1%.Patent 20091009449.X (Gao Wengui, not good big, Wang Hua, Wang Cuifang. a kind of slurry attitude bed CO ₂The method of direct synthetic dimethyl ether) use CuOZnOAl has been described ₂O ₃ZrO ₄/ MgOHZSM-5 methyl alcohol synthesizes the bifunctional catalyst with methanol dehydration, the CO that obtains ₂Conversion ratio is 12%, dimethyl ether be selectively 27%.Patent 201010046321.7 (look into and fly, Chen Haobin, Xu Yunfeng, Li Zhilin. the method for the modified montmorillonite used catalysis synthesizing dimethyl ether with carbon dioxide of a kind of CuO-ZnO-Al2O3/ catalyst) announce one and used CuOZnOAl ₂O ₃The method of/modified montmorillonite used catalysis hydrogenation of carbon dioxide synthesizing dimethyl ether catalyst, carbon dioxide conversion is up to 26.5%, and dimethyl ether selectively reaches 16.7%, and yield of dimethyl ether reaches 4.4%.

The hydrogenation of carbon dioxide dimethyl ether synthesis, need further be studied though obtaining certain achievement aspect catalyst material selection and synthesis condition, do not reach industrialization degree through the development of nearly more than ten years.

Summary of the invention

Prepare the not high situation of dimethyl ether reaction efficiency for present hydrogenation of carbon dioxide, the invention provides a kind of method of utilizing co-precipitation and hydro-thermal method to prepare the catalyst of high-ratio surface.

The process of preparation CuZnAlFe series catalysts is as follows: by m (CuO): m (ZnO): m (Al ₂O ₃)=3: 6: 1 and a certain proportion of Fe content meter are calculated the amount of the preparation required various nitrate of a certain amount of catalyst and sodium carbonate.Take according to quantity copper nitrate+partly measure zinc nitrate, aluminum nitrate+ferric nitrate+partly measure zinc nitrate, and sodium carbonate is made into the aqueous solution, wherein concentration of sodium carbonate is 8%.70 ℃ of water-baths, mixing speed 450rpm, do end liquid with the 100ml deionized water, intersect and splash into copper nitrate+zinc nitrate mixed solution and sodium carbonate liquor, stir 30min, then intersect and splash into aluminum nitrate+zinc nitrate+ferric nitrate mixed solution and sodium carbonate liquor, and to regulate pH value be 7～8, drip off rear continuation stirring 30min.The reaction unit schematic diagram is seen Fig. 1.

After reaction finishes, mixed solution is poured into autoclave, baking oven is put in sealing, and one fixs the aging certain hour of temperature, after filtration, washing (do not have Na ⁺Till), 110 ℃ of oven dry, porphyrize 40～60 orders (0.45～0.30mm) that sieve.

With the catalyst precursor porcelain boat of packing into, put into tube furnace, 400 ℃ of constant temperature calcining 2h.Be cooled to room temperature after roasting, pass into Ar gas in tube furnace, repeatedly discharge air three times, 270 ℃ of constant temperature pass into H ₂Reductase 12 h, grinding is screened to below diameter 0.1mm, carries out infrared spectrum and detects, and sees Fig. 2.Carry out simultaneously XRD and detect, see Fig. 3.Standby.

Dimethyl Ether Synthesis From Syngas is as follows: by m (catalyst)/m (HZSM-5)=take catalyst at 2: 1, ground and mixed is even in mortar, 180 ℃ of dry 24h in baking oven.Dried catalyst is put into autoclave, pass into Ar gas in reactor, with vavuum pump, reactor is vacuumized, three times repeatedly.Under normal temperature, press n (Ar): n (H ₂): n (CO ₂)=30: 3: 1 ventilation, then be heated to 270 ℃, the control stagnation pressure is 4Mpa, Experimental equipment is seen Fig. 4, collect gas with the gas collection bag and detect with gas-chromatography, detect on 7910 gas chromatographs of the gas that reaction is collected by the production of U.S. Agilent company, wherein that chromatographic column adopting is GDX-101 and GDX-401, this chromatograph is furnished with mass spectrograph, and He gas is done carrier gas.

The specific embodiment

Embodiment 1

The autoclave 5 gram composite catalysts of packing under normal temperature, are pressed n (Ar): n (H ₂): n (CO ₂Then)=30: 3: 1 ventilation is heated to 270 ℃, and the control stagnation pressure is 4Mpa, reacts after 4 hours and detects with gas-chromatography with gas collection bag collection gas, calculates carbon dioxide conversion and reaches 21.5%, selectively reaches 33.3%.

Embodiment 2

Same example [006], the reaction time reaches 6 hours, and calculate after testing carbon dioxide conversion and reach 38.8%, be selectively 41.4%.

Embodiment 3

Same example [006], the reaction time reaches 2 hours, and calculate after testing carbon dioxide conversion and reach 13.6%, be selectively 24.7%.

Example example 4

Same example [006], the reaction time is 1 hour, calculates after testing carbon dioxide conversion and reaches 5.9%, be selectively 10.3%.

Claims

1. A kind of is used for CO _Add _H The catalyzer that directly synthesizes dimethyl ether is characterized in that: (1) added Fe in the composition of CuZnAl catalyst; (2) used co-precipitation in the preparation process of catalyzer And the hydrothermal method, the obtained nano-scale precursor particles, the specific surface area is as high as 200m ² /g or more; (3) the precursor components need to go through high-temperature calcination and H2 reduction process before use, and then need to add HZSM-5 carrier It can be used as a dehydrating agent to make a composite catalyst.

2. The nanocomposite catalyst obtained according to right 1 is used for _CO2 plus _H2 to synthesize dimethyl ether, the _CO conversion rate reaches more than 60%, the selectivity of dimethyl ether reaches more than 50%, and the yield can reach more than 80% .