CN105214704A

CN105214704A - A kind of preparation method of catalyst

Info

Publication number: CN105214704A
Application number: CN201510718695.1A
Authority: CN
Inventors: 沈秋
Original assignee: Wuxi Qingyang Machinery Manufacturing Co Ltd
Current assignee: Wuxi Qingyang Machinery Manufacturing Co Ltd
Priority date: 2015-10-29
Filing date: 2015-10-29
Publication date: 2016-01-06

Abstract

The invention discloses a kind of preparation method of catalyst, this catalyst is molybdenum carbide catalyst, by molybdenum oxide after compressing tablet, screening, prepare this catalyst by the heating rate controlling the differential responses stage, comprising: ammonium molybdate roasting prepares heating rate-passivation that molybdenum oxide-molybdenum oxide compressing tablet-molybdenum oxide sieve-passes into blender carbonization-control different phase.Sintering temperature is 600-650 degree, and the time is 2-3h.Gaseous mixture is CH ₄: H ₂for 1:3, volume space velocity is 7000-8000/h.Heating rate is room temperature to being after 6K/min, 623K be 1k/min during 623K, and adopt thermocouple collecting temperature data, Controlled by Programmable Controller temperature, precision is ± 1 degree.The molybdenum carbide catalyst grain shape that this invention prepares is regular, and size is even, and purity is high, in the chemical reaction such as desulfurization, denitrogenation, have good catalytic action.

Description

A kind of preparation method of catalyst

Technical field

The present invention relates to a kind of preparation method of catalyst.

Background technology

In current oil exploitation, mink cell focus ratio is increasing gradually, in oil the content of heterocyclic compound and annelation degree also more and more higher.The existence of these heterocyclic compounds not only produces poisoning effect to the deep-processing process of oil product, and brings serious environmental pollution.According to the promise of China's WTO accession, within 2007, product oil wholesale market will be opened.The Beijing Olympic Green of 2008 is come up to us, improve fuel environment protection quality, produce the clean gasoline of more environmental protection, diesel oil, control automobile exhaust pollution, be that petroleum refining industry of China meets Domestic Automotive Industry to develop, international oil product is competed and is guaranteed that Beijing Olympic Green successfully waits key subjects of challenge.

In platinum and its periodic table of elements, adjacent element is widely used in the chemical industrial field of chemical synthesis, petrochemical industry, polymerization and environmental protection as catalyst.But platinum group metal or the 8th group 4 transition metal, particularly platinum, palladium, rhodium etc. are rare precious metals, and its reserves reduce year by year, and demand increases year by year. some scientists and aerospace mechanism propose exploitation aerolite, because meteoritic abundance contains the carbide of tungsten and molybdenum.It is through specific preparation technology, and obtained tungsten carbide and aluminium carbide have the catalytic performance identical with platinum group metal, thus have found the material that can substitute platinum group metal---tungsten carbide and molybdenum carbide.

In recent years, the carbide of the transition metal of high-specific surface area and this two classes new material of nitride demonstrate the catalytic desulfurization of great theoretical significance and broad prospect of application, particularly molybdenum nitride and molybdenum carbide at catalytic field, nitrogen removal performance attracts much attention.With regard to catalyst system and catalyzing, molybdenum nitride and molybdenum carbide are different from oxide and sulfide, its preparation process and conventional catalyst completely different, it is " topotactic reaction " that utilize under temperature programming, is made up of the thermal response of gas, solid phase.With regard to catalysis characteristics, the hydrogenation activity of molybdenum nitride and molybdenum carbide is suitable with the noble metal such as platinum and palladium.In hydrofining reaction, aluminium nitride is very high selective to having containing the cracking of heteroatomic ring, and relatively little to the hydrogenation activity of aromatic rings, greatly can reduce the hydrogen consumption in hydrofinishing, have larger industrial significance.Fruitful to the research of this kind of catalyst in the world.Molybdenum nitride, as the potential catalysis material of function admirable, must possess high specific area.The early stage synthesis high-temperature heating method of nitride can obtain the nitride that granularity is 2 ~ 10nm; The nitride that granularity is 5 ~ 50nm can be prepared by plasma sputtering method.But the specific area of these method synthetic products is general all very little.Utilizing Mo or its oxide and NH3 to carry out gas-solid reaction method, to prepare molybdenum nitride be another approach synthesizing molybdenum nitride.Toth in 1971 first reported and generates Y-Mo at 600 ~ 80012 times by Mo and NH3 reaction, but specific area is little.Oyama in 1981 etc. have done improvement to the method, and the specific area of the Y-Mo:N of generation can improve.Volpe in 1985 etc. utilize temperature-programmed technique, strict control heating rate and NH, air speed, and the specific area of its fresh product of Y-M02N of result synthesis is up to 220m2/g.Programmed temperature method is that the synthesis of high-specific surface area molybdenum nitride opens up a new way.

The nitrogen (carbon) of high-specific surface area changes aluminium by a series of " topotactic reaction " by the result of nitrogenize or carbonization." topotactic reaction " is that the form that product is same as parent precursor with crystal structure is formed, and the crystal structure of parent precursor remains unchanged substantially.Because molybdenum nitride is finer and close than aluminium oxide, such reaction will cause that molybdenum nitride crystal has crack to produce, formed multi-pore channel high-specific surface area material.Only have and keep whole " topotactic reaction " to carry out very lentamente, substantially could generate Y-M02N under the condition not destroying M003 crystal phase structure.

Synthesis different metal carbide is different with the reaction temperature of nitride, and the fusing point of synthesis reaction temperature and parent oxide has direct relation, and in building-up process, synthesis gas air speed is a key factor.It is the key factor determining specific area and phase composition that Choi etc. highlight reaction intermediate.

Because the surface nature of aluminium nitride and molybdenum carbide and characterization of adsorption are very similar to VIII race's noble metal, so, about the early stage research work of carbide and nitride catalyst performance is always associated with the characteristic reaction of noble metal, to find a kind of non-precious metal catalyst that can substitute noble metal platinum and palladium.In recent years, about the catalytic activity that molybdenum nitride and molybdenum carbide show in hydrodesulfurization and hydrodenitrogeneration reaction, the very large interest .Schlatter etc. of people is caused to have studied molybdenum nitride and molybdenum carbide to the hydrodenitrogenationactivity activity of quinoline, when making raw material with the tetradecane solution of quinoline under existing without sulfide, molybdenum carbide shows with active like nickel sulfide molybdenum/alumina type, but hydrogen consumption obviously reduces, and the primary product of hydrodenitrogeneration is unsaturated alkyl benzene.The hydrodenitrogenationactivity activity of M02c decreases a little, and selective reduction is more obvious.This may with formation low optionally MoS: superficial layer is relevant.The molybdenum nitride (108m2/g) of the synthesizing high specific surface area first such as Markel. and utilize thiophene to study as model compound, can find out from product distribution, Mo:N catalysis rhohene desulfiirization directly generates butadiene, butane and butylene.Butadiene is rapidly converted into butylene, is finally converted into butane stable on thermodynamics.Compared with cobalt nickel sulfide catalyst, M02N shows strong hydrogenation activity.Bell etc. have studied Mo:N catalyst to the hydrodenitrogeneration of the organic nitrogen compounds such as quinoline, benzofuran, benzothiophene and indoles and organic sulfur compound and desulphurizing activated.Find the investigation of the relation of asking of distribution of reaction products and reaction temperature, phenyl ring is hydrogenation not, and also found that the pyrolysis product .Nagai etc. of alkyl on phenyl ring thinks, the hydrogenation activity of the M02N catalyst of pulverulence is high and hydrogenolysis desulfuration selectivity is low simultaneously.They make model compound with dibenzothiophenes, analyze the hydrodesulfurization product distribution of dibenzothiophenes and contrast with industrial molybdenum sulfide catalyst, find the activity of Nitrides Catalysts be molybdenum sulfide catalyst I.2 doubly, and when reaction temperature is low, molybdenum nitride catalytic activity is higher, biphenyl in molybdenum nitride catalytic reaction products/cyclohexyl benzene value exceeds 91 times (at 553 DEG C) and 12 times (at 593 DEG C) than molybdenum sulfide catalyst product, has significantly directly hydrogenolysis desulfuration selectivity.The high selectivity that nitride reacts hydrodesulfurization and hydrodenitrogeneration, when making organic sulfide removal and nitrogen in petroleum refining process, can save valuable hydrogen resource.AjoyRaje etc. utilize low-sulfur content coal liquefaction gasoline as raw material, research hydrodenitrogeneration and hydrodesulfurization.

Adopt ADSORPTION IN A FIXED BED PROCESS FOR TREATMENT through the refined diesel oil of common process (sulfur content is less than 0.296), when effluent oil sulphur, nitrogen content exceed restriction index, just hydrocracking is carried out to the inorganic agent of absorption sulphur, nitride, add hydrogen desorption post-treatment agent simultaneously and regenerated and recycle.Screened by M element kind and preparation method's research and development absorption and the good Multifunctional Additive of hydrogenolysis performance.The selective enrichment of developing low-cost and hydrogenolysis prepare the innovative technology of clean fuel oil.Multifunctional Additive saturated adsorption desulphurizing ability is greater than 40mL oil/g inorganic agent; Trace Sulfur is measured by Coulomb equation and x XRF.In a word, transition metal nitride, carbide show tempting prospect in fields such as petroleum refining and chemical industry, fuel cell, gas chemical industries.But, relevant transition metal carbide, nitride are just come into one's own the nearly more than ten years at catalytic field, as novel energetic catalysis material, its kind and preparation method need to be excavated further, especially multi-component alloy material, its Surface Science more needs to be studied the rule disclosing its physico-chemical property and catalytic performance deeply, thus find the feasible method preparing the carbonitride of high-ratio surface on a large scale, and prepare that activity and selectivity is higher, the better new catalytic material of stability.

Transition metal nitride has the stuctures and properties different from metal sulfide and metal oxide, transition metal high surface area catalysts is very special to the adsorption property of hydrogen, not only at room temperature just can generate Irreversible Adsorption hydrogen, and also can generate Irreversible Adsorption hydrogen under middle temperature; Its similar noble metal of activity in hydrogenation reaction is a kind of up-and-coming novel hydrogenation catalysis material ...The carbide of current research all shows very excellent catalytic performance in a series of reaction, these reactions comprise the hydrotreatment of petroleum cuts, the isomerization of hydrocarbon, the hydrogenation of oxycarbide and F-T synthetic reaction, electrode reaction in fuel cell, the conversion of methane, dehydroaromatizationof of alkane etc., in these reactions of carbide institute catalysis, show catalytic activity that can be comparable with noble metal, some has even exceeded noble metal.Since Schlattert etc. has reported since the hydrodenitrogeneration of transition metal carbide to quinoline have good catalytic activity, about carbide all shows very excellent catalytic performance for the hydrogenation essence of petroleum cuts.The result of study of the people such as Aegerter shows, aluminium oxide is supported to the catalyst of Mo, and at 693K, molybdenum carbide catalyst is that molybdenum sulfide catalyst is to 1.5 of rhohene desulfiirization activity times.The result of study of the people such as Schlatter is that aluminium carbide has the activity suitable with commercial NiMo/A1203 sulphided state catalyst.

Summary of the invention

The object of the invention is to the preparation method proposing a kind of catalyst.

For reaching this object, the present invention by the following technical solutions:

A kind of preparation method of catalyst, this catalyst is molybdenum carbide catalyst, by molybdenum oxide after compressing tablet, screening, this catalyst is prepared, comprising: ammonium molybdate roasting prepares molybdenum oxide---molybdenum oxide compressing tablet---molybdenum oxide screening------heating rate of control different phase---passivation that passes into blender carbonization by controlling the heating rate in differential responses stage.Sintering temperature is 600---650 degree, the time is 2---and 3h.Gaseous mixture is CH ₄: H ₂for 1:3, volume space velocity is 7000---8000/h.Heating rate is room temperature to being after 6K/min, 623K be 1k/min during 623K, and adopt thermocouple collecting temperature data, Controlled by Programmable Controller temperature, precision is ± 1 degree.

Detailed description of the invention

Embodiment 1

A kind of preparation method of catalyst, this catalyst is molybdenum carbide catalyst, by molybdenum oxide after compressing tablet, screening, this catalyst is prepared, comprising: ammonium molybdate roasting prepares molybdenum oxide---molybdenum oxide compressing tablet---molybdenum oxide screening------heating rate of control different phase---passivation that passes into blender carbonization by controlling the heating rate in differential responses stage.Sintering temperature is 650 degree, and the time is 3h.Gaseous mixture is CH ₄: H ₂for 1:3, volume space velocity is 7000/h.Heating rate is room temperature to being after 6K/min, 623K be 1k/min during 623K, and adopt thermocouple collecting temperature data, Controlled by Programmable Controller temperature, precision is ± 1 degree.

Embodiment 2

A kind of preparation method of catalyst, this catalyst is molybdenum carbide catalyst, by molybdenum oxide after compressing tablet, screening, this catalyst is prepared, comprising: ammonium molybdate roasting prepares molybdenum oxide---molybdenum oxide compressing tablet---molybdenum oxide screening------------cooling fast---passivation that controls the heating rate of different phase that passes into blender carbonization that passes into ammonia nitrogenize by controlling the heating rate in differential responses stage.Sintering temperature is 650 degree, and the time is 3h.Gaseous mixture is CH ₄: H ₂for 1:4, volume space velocity is 7500/h.Heating rate is room temperature to being after 5K/min, 600K be 1.5k/min during 600K, and cool time is 10min, and adopt thermocouple collecting temperature data, Controlled by Programmable Controller temperature, precision is ± 1 degree.

Claims

1. the preparation method of a catalyst, this catalyst is molybdenum carbide catalyst, it is characterized in that molybdenum oxide after compressing tablet, screening, this catalyst is prepared, comprising: ammonium molybdate roasting prepares molybdenum oxide---molybdenum oxide compressing tablet---molybdenum oxide screening------heating rate of control different phase---passivation that passes into blender carbonization by controlling the heating rate in differential responses stage.

2. method according to claim 1, is characterized in that, described sintering temperature is 600---650 degree, the time is 2---and 3h.

3. method according to claim 1, is characterized in that, described gaseous mixture is CH ₄: H ₂for 1:3, volume space velocity is 7000---8000/h.

4. method according to claim 1, is characterized in that, described heating rate is room temperature to being after 6K/min, 623K be 1k/min during 623K, and adopt thermocouple collecting temperature data, Controlled by Programmable Controller temperature, precision is ± 1 degree.