High-dispersion vulcanized CoMoSxOyPreparation method and application of @ C bimetallic catalyst
阅读说明：本技术 一种高分散硫化CoMoSxOy@C双金属催化剂的制备方法和应用 (High-dispersion vulcanized CoMoSxOyPreparation method and application of @ C bimetallic catalyst ) 是由 魏贤勇 刘光辉 宗志敏 柳方景 麻志浩 闫卫卫 于 2019-09-26 设计创作，主要内容包括：一种高分散硫化CoMoS_xO_y@C双金属催化剂的制备方法和应用,负载型催化剂技术领域。双金属硫化态催化剂的制备方法,选用α-纤维素作为生物炭源,将金属Co和Mo分散在α-纤维素上,干燥后置于管式炉中缓慢原位热解,得到Co、Mo双金属高度分散的前驱体Co-MoO_2@C；最后,将该前驱体进行硫化,得到金属高度分散的生物炭负载的CoMoS_xO_y双金属硫化态催化剂。优点：该制备工艺简单,原料廉价易得,相比于非负载型金属硫化物来说,降低了对设备的腐蚀性以及固废处理费用,所得到的催化剂应用于褐煤相关模型化合物以及褐煤的催化加氢裂解,表现出优异的活性,且稳定性好、生产周期短。(High-dispersion vulcanized CoMoS x O y A preparation method and application of a @ C bimetallic catalyst, belonging to the technical field of supported catalysts. The preparation method of the bimetal sulfuration state catalyst comprises the steps of selecting alpha-cellulose as a charcoal source, dispersing metal Co and Mo on the alpha-cellulose, drying, placing in a tubular furnace for slow in-situ pyrolysis to obtain a Co-MoO precursor with highly dispersed Co and Mo bimetal 2 @ C; finally, vulcanizing the precursor to obtain the highly metal-dispersed charcoal-loaded CoMoS x O y A bimetallic sulfided catalyst. The advantages are that: the preparation process is simple, the raw materials are cheap and easy to obtain, the corrosivity to equipment and the solid waste treatment cost are reduced compared with those of non-supported metal sulfides, and the obtained catalyst is applied to catalytic hydrocracking of lignite-related model compounds and lignite, shows excellent activity and has good stabilityAnd the production period is short.)
1. High-dispersion vulcanized CoMoSxOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: the preparation method of the bimetallic sulfuration catalyst selects alpha-cellulose as a biochar source and uses metal Co and Mo are dispersed on alpha-cellulose, dried and then placed in a tube furnace for slow in-situ pyrolysis to obtain a Co-MoO precursor with highly dispersed Co and Mo double metals2@ C; finally, vulcanizing the precursor to obtain the highly metal-dispersed charcoal-loaded CoMoSxOyA bimetallic sulfided catalyst.
2. High dispersion vulcanized CoMoS according to claim 1xOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: the preparation method comprises the following specific steps:
the method comprises the following steps: weighing Co (NO)3)2·6H2O and (NH)4)6Mo7O24·4H2O, dispersing in the selected solution, and stirring at 60 ℃ for later use; the selected solution comprises any one of deionized water, methanol, ethanol or acetone;
step two: weighing 10-100g of alpha-cellulose, slowly adding the alpha-cellulose into the solution obtained in the first step, and continuously stirring for 24 hours until the alpha-cellulose is uniformly dispersed;
step three: removing the solution in the mixed system in the second step by reduced pressure distillation, then placing the mixed system into a forced air drying oven, and drying the mixed system for 4 hours at 120 ℃ to remove the residual solution;
step four: the powder dried in step three is then placed in a tube furnace under N2Heating to 650 ℃ under the atmosphere and keeping for 4 h; cooling and taking out to obtain a highly dispersed bimetal precursor Co-MoO2@C；
Step five: subjecting a bimetallic precursor Co-MoO2@ C and calculated amount of sulfur powder are placed in high-pressure autoclave, and H is charged2And vulcanizing to obtain the bimetallic vulcanized CoMoSxOy@ C catalyst.
3. High dispersion vulcanized CoMoS according to claim 2xOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: in the first step, Co (NO)3)2·6H2O and (NH)4)6Mo7O24·4H2Amount of O addedBased on a mass ratio of Co to Mo of 1 to 3, the total loading was 20 wt% of the support.
4. High dispersion vulcanized CoMoS according to claim 2xOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: in the second step, the alpha-cellulose is a carbon source of the catalyst.
5. High dispersion vulcanized CoMoS according to claim 2xOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: in the fourth step, N is required2Heating to 650 ℃ and holding for 4h under an atmosphere is intended to ensure adequate pyrolysis of the alpha-cellulose and to promote high dispersion of the bimetal.
6. High dispersion vulcanized CoMoS according to claim 2xOyThe preparation method of the @ C bimetallic catalyst is characterized by comprising the following steps of: in the fifth step, the initial hydrogen pressure is 4MPa, the vulcanization temperature is 340 ℃, and the time is 4 hours, so as to ensure that the metal sulfide has enough thermal stability.
7. A highly dispersed sulfurized CoMoS as defined in claim 1xOyThe application of the bimetallic catalyst prepared by the preparation method of the @ C bimetallic catalyst is characterized in that:
charcoal-loaded CoMoSxOyThe application of the bimetallic sulfurized catalyst in the catalytic hydrocracking of lignite related model compound and lignite comprises the following steps:
the method comprises the following steps: 0g or 5g CoMoSxOyCatalyst and 20g of lignite powder are placed in a 1L high-pressure reaction kettle, and 200mL of cyclohexane is added;
step two: with N2Replacing air in the kettle and filling 1MPa H2Reacting for 4 hours at 320 ℃, finishing the reaction, and cooling by using an ice water bath;
step three: thoroughly extracting the reaction mixture by using petroleum ether with a boiling range of 30-60 ℃ to obtain petroleum ether soluble substances, namely light components;
step four: then, the extraction is continued by using the mixed solvent of acetone and carbon disulfide with the same volume, and soluble matters, namely heavy components, of the mixed solvent of acetone and carbon disulfide with the same volume are obtained.
Technical Field
The invention relates to the technical field of supported catalysts, in particular to high-dispersion vulcanized CoMoSxOyA preparation method and application of a @ C bimetallic catalyst.
Background
The direct liquefaction process of the lignite can obtain light tar with rich components from the lignite, is an important chemical raw material, can separate various chemicals such as carbazole, quinoline, phenol oil and the like from the lignite, can further upgrade the lignite into clean liquid fuel through catalytic hydrogenation conversion, and has great utilization space and utilization value. However, the yield of light tar obtained by the method still needs to be improved, and the selection of the catalyst has many concerns, such as the cost, stability and reactivity of the catalyst.
Disclosure of Invention
The invention aims to provide high-dispersion vulcanized CoMoS which has relatively simple, safe and feasible preparation process and technique and can be produced in large scalexOyThe preparation method and the application of the @ C bimetallic catalyst solve the problems of poor mass transfer and poor metal dispersion degree in the traditional supported catalyst preparation.
The purpose of the invention is realized as follows: the preparation method of the bimetal sulfuration state catalyst comprises the steps of selecting alpha-cellulose as a charcoal source, dispersing metal Co and Mo on the alpha-cellulose, drying, placing in a tubular furnace for slow in-situ pyrolysis to obtain a Co-MoO precursor with highly dispersed Co and Mo bimetal2@ C; finally, vulcanizing the precursor to obtain the highly metal-dispersed charcoal-loaded CoMoSxOyA bimetallic sulfided catalyst.
The preparation method comprises the following specific steps:
the method comprises the following steps: weighing Co (NO)3)2·6H2O and (NH)4)6Mo7O24·4H2O, dispersing in the selected solution, and stirring at 60 ℃ for later use; the selected solution comprises any one of deionized water, methanol, ethanol or acetone;
step two: weighing 10-100g of alpha-cellulose, slowly adding the alpha-cellulose into the solution obtained in the first step, and continuously stirring for 24 hours until the alpha-cellulose is uniformly dispersed;
step three: removing the solution in the mixed system in the second step by reduced pressure distillation, then placing the mixed system into a forced air drying oven, and drying the mixed system for 4 hours at 120 ℃ to remove the residual solution;
step four: the powder dried in step three is then placed in a tube furnace under N2Heating to 650 ℃ under the atmosphere and keeping for 4 h; cooling and taking out to obtain a highly dispersed bimetal precursor Co-MoO2@C；
Step five: subjecting a bimetallic precursor Co-MoO2@ C and calculated amount of sulfur powder are placed in high-pressure autoclave, and H is charged2And vulcanizing to obtain the bimetallic vulcanized CoMoSxOy@ C catalyst.
In the first step, Co (NO)3)2·6H2O and (NH)4)6Mo7O24·4H2The amount of O added is based on the mass ratio of Co to Mo being 1:3, and the total loading amount is 20 wt% of the carrier.
In the second step, the alpha-cellulose is a carbon source of the catalyst.
In the fourth step, N is required2Heating to 650 ℃ and holding for 4h under an atmosphere is intended to ensure adequate pyrolysis of the alpha-cellulose and to promote high dispersion of the bimetal.
In the fifth step, the initial hydrogen pressure is 4MPa, the vulcanization temperature is 340 ℃, and the time is 4 hours, so as to ensure that the metal sulfide has enough thermal stability.
Charcoal-loaded CoMoSxOyThe application of the bimetallic sulfurized catalyst in the catalytic hydrocracking of lignite related model compound and lignite comprises the following steps:
the method comprises the following steps: 0g or 5g CoMoSxOyCatalyst and 20g of lignite powder are placed in a 1L high-pressure reaction kettle, and 200mL of cyclohexane is added;
step two: with N2Replacing air in the kettle and filling 1MPa H2Reacting for 4 hours at 320 ℃, finishing the reaction, and cooling by using an ice water bath;
step three: thoroughly extracting the reaction mixture by using petroleum ether with a boiling range of 30-60 ℃ to obtain petroleum ether soluble substances, namely light components;
step four: then, the extraction is continued by using the mixed solvent of acetone and carbon disulfide with the same volume, and soluble matters, namely heavy components, of the mixed solvent of acetone and carbon disulfide with the same volume are obtained.
The method has the beneficial effects that due to the adoption of the scheme, the Co and Mo metals are highly dispersed on the charcoal carrier and in the pore channel in an in-situ Co-pyrolysis mode, and the harsh H condition is avoided by the simple vulcanization process2S or H2And the use of flammable and explosive gases simplifies the preparation steps of the catalyst, and simultaneously solves the problems of poor mass transfer, poor metal dispersion degree and the like in the preparation of the traditional supported catalyst. The method embodies the atom economy and achieves the effects of lignite-related model compounds and the catalytic hydrocracking of lignite.
The method comprises the following steps of (1) using cheap and easily-obtained alpha-cellulose as a charcoal source, and impregnating Co and Mo metals on the alpha-cellulose according to a certain proportion by an impregnation method; co and Mo species are embedded into a charcoal carrier in an in-situ Co-pyrolysis manner; then obtaining the charcoal-loaded CoMoS through vulcanizationxOyA bimetallic sulfided catalyst. The catalyst has high dispersion degree of two metals, and no obvious agglomeration after vulcanization. The preparation scheme provided by the invention has the advantages of simple and safe conditions and short production period. The catalyst is used for catalytic hydrocracking of lignite-related model compounds and lignite, shows excellent catalytic activity, and can effectively crack>C-O-bridge bond and remarkably improves the yield of the light tar derived from the lignite.
The problems of poor mass transfer and poor metal dispersion degree in the traditional supported catalyst preparation are solved, and the purpose of the invention is achieved.
The advantages are that: the preparation process is simple, the raw materials are cheap and easy to obtain, and compared with non-supported metal sulfides, the preparation process reduces the corrosivity on equipment and the solid waste treatment cost. The obtained catalyst is applied to catalytic hydrocracking of lignite related model compounds and lignite, shows excellent activity, and is good in stability and short in production period.
Drawings
FIG. 1 is an X-ray diffraction pattern of a biochar-supported Co, Mo or CoMo metal sulfided catalyst of the present invention.
FIG. 2 is a comparative transmission electron micrograph of a biochar-supported Co, Mo or CoMo metal sulfided catalyst of the present invention before and after sulfiding.
FIG. 3 is a biochar-loaded CoMoS of the inventionxOyX-ray photoelectron spectroscopy of the catalyst.
FIG. 4 is a biochar-loaded CoMoS of the inventionxOyThe tar yield chart of the catalyst used for lignite catalytic hydrocracking.
Detailed Description