CN106944115B

CN106944115B - A kind of heteropoly acid ammonium salt form catalyst and preparation method thereof

Info

Publication number: CN106944115B
Application number: CN201610003174.2A
Authority: CN
Inventors: 金浩; 孙素华; 朱慧红; 杨光
Original assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Current assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Priority date: 2016-01-07
Filing date: 2016-01-07
Publication date: 2019-06-11
Anticipated expiration: 2036-01-07
Also published as: CN106944115A

Abstract

The invention discloses a kind of heteropoly acid ammonium salt form catalyst and preparation method thereof.The catalyst includes active component, the carrier containing auxiliary agent, and active component is ammonium heteropoly acids, and carrier is the silica of nickel containing auxiliary agent and iron；On the basis of the weight of catalyst, the content of ammonium heteropoly acids is 3% ~ 35%, and for auxiliary agent in terms of oxide, the content of nickel oxide is 3% ~ 18%, and the content of di-iron trioxide is 1% ~ 10%, and the content of silica is 37% ~ 93%.Catalyst of the present invention is ethylene reaction produced especially suitable for the dehydration that low-concentration ethanol aqueous solution is raw material, which not only has the characteristics that low temperature active is high, selectivity is good, has strong anti-carbon capacity, and stability is good.

Description

A kind of heteropoly acid ammonium salt form catalyst and preparation method thereof

Technical field

The present invention relates to a kind of heteropoly acid ammonium salt form catalyst and preparation method thereof, de- for ethyl alcohol more particularly to one kind The aquatic agent of carried heteropoly acid ammonium salt in catalysis and its preparation method for producing ethylene.

Background technique

Flagship product of the ethylene as basic Organic Chemicals and petro chemical industry, about 75% chemical products It is to be prepared by raw material of ethylene, therefore the size of ethylene yield has become one national oil development of chemical industry water of measurement Flat important symbol.Traditional ethylene is mainly the heavy dependence petroleum resources as made from light petroleum fraction cracking.With The day of international energy situation is becoming tight, and petroleum resources are increasingly exhausted, and developing new renewable alternative energy source has been the task of top priority.

Recently, ethyl alcohol especially recyclable organism preparing ethylene by dehydrating ethanol is increasingly valued by people, and is had Green, sustainable, various advantages such as reaction condition is mild and product ethylene is with high purity.Bio-ethanol is mainly derived from agriculture The fermentation of byproduct can avoid the dependence to petroleum resources, deficient in some petroleum resources such as Brazil, India, Pakistan Country continues to use always this method production ethylene, and this point more has realistic meaning to the country of oil-poor and few oil.Ethanol dehydration prepares second Alkene has the great potential for partly or entirely replacing obtaining ethylene from petroleum.Therefore, research producing ethylene from dehydration of ethanol has great Economic value and strategic importance.

There are many catalyst for ethanol delydration to ethylene report, mainly activated alumina, molecular sieve and heteropoly acid etc..It is living Property aluminium oxide is cheap as catalyst, and activity and selectivity is preferable, but reaction temperature is high, and reaction velocity is low, energy Consumption is high, and utilization rate of equipment and installations is low.The catalytic activity and selectivity of molecular sieve are high, stablize；Reaction temperature is low, and reaction velocity is big, but Catalyst life is short, and amplification factor is small, limits its industrialized production.Heteropoly acid is by central atom and coordination atom with one Fixed structure passes through oxygen-containing polyacid made of oxygen atom ligand bridging, has many advantages, such as highly acid.In producing ethylene from dehydration of ethanol The characteristics of in reaction, heteropolyacid catalyst has reaction temperature low, selectivity height and high income.

Li Benxiang etc. [Chemical Engineering Technology and exploitation, 2010,5 (39): 7-9] reports entitled MCM-41 load Catalyzed by Silicotungstic Acid The article of producing ethylene from dehydration of ethanol, catalyst are prepared using infusion process.CN200910057539.X discloses a kind of ethanol dehydration The catalyst of ethylene processed.For the catalyst using aluminium oxide as carrier, active component is heteropoly acid, is prepared using kneading method.It is above-mentioned to urge Agent shows higher catalytic activity and selectivity when using high concentration ethanol as raw material, but working as with low-concentration ethanol is original When material, catalyst activity is decreased obviously, and stability is bad.

Summary of the invention

Place in order to overcome the shortcomings in the prior art, the present invention provides a kind of heteropoly acid ammonium salt form catalyst and its systems Preparation Method.The catalyst not only has the characteristics that low temperature active is high, selectivity is good, has strong anti-carbon capacity, and stability is good.

Heteropoly acid ammonium salt form catalyst of the present invention, including active component, containing the carrier of auxiliary agent, active component is heteropoly acid ammonium Salt is shown in formula (1) that carrier is the silica of nickel containing auxiliary agent and iron；On the basis of the weight of catalyst, the content of ammonium heteropoly acids is 3% ~ 35%, preferably 12% ~ 30%, further preferably 18% ~ 30%, for auxiliary agent in terms of oxide, the content of nickel oxide is 3% ~ 18%, Preferably 5% ~ 15%, the content of di-iron trioxide is 1% ~ 10%, preferably 2% ~ 7%, and the content of silica is 37% ~ 93%, preferably It is 48% ~ 81%, further preferably 48% ~ 76%；

H_m(NH₄)_nYX₁₂O₄₀(1)

Wherein X represents W or Mo, and Y represents Si or P；When Y represents Si, m+n=4, n value is 0.1 ~ 1.0；When Y represents P When, m+n=3, n value is 0.1 ~ 1.0.

In the heteropoly acid ammonium salt form catalyst, ammonium heteropoly acids are distributed in the outer surface of carrier.That is, urging Substantially without heteropoly acid ammonium in agent duct.

The property of the silica support of the nickel containing auxiliary agent and iron is as follows: specific surface area is 400 ~ 750 m²/ g, Kong Rongwei 0.50 ~ 0.80 mL/g, average pore diameter are 4.1 ~ 6.2 nm.

The preparation method of the heteropoly acid ammonium salt form catalyst, comprising:

(1) preparation of the silica support of nickel containing auxiliary agent and iron；

(2) step (1) resulting catalyst carrier is added in autoclave, carries out also original place to it using hydrogen Reason；

(3) polyalcohol and/or furfuryl aldehyde solution are added in autoclave, then adjusting Hydrogen Vapor Pressure to 2~4MPa, 0.5~5.0h is reacted at 100~300 DEG C；

(4) product that step (3) reaction obtains, through drying to sample surfaces under low temperature without liquid phase, is catalyzed through filtering Agent precursor A；

(5) the catalyst precarsor A that step (4) obtains being added in aqueous solutions of organic acids, heating stirring to solution is evaporated, Obtain catalyst precarsor B；

(6) the catalyst precarsor B that step (5) obtains is added in the alkaline solution containing ammonium, through filtering, 40 DEG C ~ 90 It is dry at DEG C；Or the material that step (5) obtains is adsorbed into ammonia at 40 DEG C ~ 90 DEG C, obtain catalyst precarsor C；

(7) aqueous solution of heteropoly acid is added in the catalyst precarsor C that step (6) obtains, heating stirring to solution is steamed It is dry, then through dry and roasting to get catalyst.

The method of the present invention, the preparation of the silica support of nickel containing auxiliary agent and iron in step (1), it is preferred to use following method:

A, iron containing compounds and template are added in the aqueous solution of organic acid, obtain solution I；

B, silicon source is added in solution I, is then stirred at 60 DEG C ~ 90 DEG C at gel；

C, iron-containing silica support is made through aging, dry and roasting in the resulting gel of step B；

D, the silica support of iron content and nickel is obtained on nickel load to iron-containing silica support using infusion process.

In step A, the iron containing compounds are soluble molysite, generally ferric nitrate, ferric sulfate, in iron chloride It is one or more；The organic acid is one of citric acid, tartaric acid, malic acid or a variety of, the organic acid and carrier Middle SiO₂Molar ratio be 0.1 ~ 1.2.

In step A, the template is cetyl trimethylammonium bromide, hexadecyltrimethylammonium chloride, dodecane Base sodium sulphate, triblock polymer P123, triblock polymer F127, triblock polymer F108, molecular weight be 1000 ~ One of 10000 polyethylene glycol is a variety of, SiO in the template and carrier₂Molar ratio be 0.01 ~ 1.2.

In step B, the silicon source is one of ethyl orthosilicate, silica solution or a variety of.

In step C, molding silica support can be made in the silica support, be also possible to be not required to molding oxygen SiClx carrier, those skilled in the art determine according to selected technique.Molding silica support can use existing Conventional molding techniques form, such as extruded moulding, compression molding etc., and shape can be bar shaped, spherical shape, sheet etc..It is forming In the process, it can according to need addition binder and shaping assistant, binder generally use small porous aluminum oxide.Shaping assistant is such as Peptizing agent, extrusion aid etc..

In step C, the drying and roasting are carried out using usual manner, and the dry condition generally used is as follows: 90 DEG C ~ 120 DEG C of dry 3h ~ 12h are roasted generally in 300 DEG C ~ 800 DEG C roasting 2 h ~ 6 h.

In step D, the infusion process can use conventional method, such as saturation infusion process, supersaturated infusion process etc., leaching Generally require after stain as follows by dry and roasting process, drying condition: 90 DEG C ~ 120 DEG C dry 3h ~ 12h, roasting condition is such as Under: in 300 DEG C ~ 500 DEG C roasting 2 h ~ 6 h.Wherein, nickel source used when infusion process nickel-loaded is soluble nickel salt, generally For one of nickel nitrate, nickel acetate or a variety of.

In step (5), the temperature of the heating stirring is generally 40 DEG C ~ 90 DEG C.

In step (7), the temperature of the heating stirring is generally 40 DEG C ~ 90 DEG C.

In step (7), the drying condition is as follows: in 90 DEG C ~ 120 DEG C drying h of 3 h ~ 12, the roasting condition It is as follows: in 300 DEG C ~ 550 DEG C roasting 2 h ~ 6 h.

In step (2), the reduction treatment process is as follows: under hydrogen atmosphere by catalyst carrier be warming up to 300 DEG C~ 600 DEG C, 4h~8h is handled at 0.1MPa~0.5MPa.Wherein reduction treatment can use pure hydrogen, can also be using containing lazy Property gas hydrogen, hydrogen volume concentration be 30% ~ 100%.

In step (3), the polyalcohol is one of C5~C10 polyalcohol or a variety of, preferably xylitol, sorb One of alcohol, mannitol, arabite are a variety of；The mass concentration of polyalcohol and/or furfuryl aldehyde solution is 5%~35%, preferably It is 5%~30%, the additional amount of polyalcohol and/or furfural and the mass ratio of step (1) resulting catalyst carrier are 2:1 ~ 10:1, Preferably 3:1 ~ 10:1.

In step (5), the organic acid is one of citric acid, tartaric acid, malic acid or a variety of.The organic acid With SiO in carrier₂Molar ratio be 0.05 ~ 0.50.

In step (6), the catalyst precarsor B that step (5) obtains is added in the alkaline solution containing ammonium and is impregnated, soaked The stain time is generally the min of 5 min ~ 30.The catalyst precarsor B that step (5) is obtained adsorbs ammonia, and adsorption time is generally 5 min~30 min.In step (6), the alkaline solution containing ammonium is ammonium hydroxide, sal volatile, one in ammonium bicarbonate soln Kind is a variety of.

In step (6), pure ammonia is can be used in the ammonia, the gaseous mixture containing ammonia can also be used, in mixed gas It is other for one of inert gas such as nitrogen, argon gas etc. or a variety of in addition to ammonia.

In step (7), the heteropoly acid is one of phosphotungstic acid, silico-tungstic acid, phosphomolybdic acid or a variety of.

It can also be added in the silica support in mesopore molecular sieve, such as SBA-15, SBA-3, MCM-41 etc. One or more, the weight content of molecular sieve in the carrier is 10% hereinafter, generally 1% ~ 8%.Mesopore molecular sieve can aoxidize It introduces, can also be introduced during plastic before silicon plastic, can also be introduced after silica plastic, it can be with silica support Kneading introduces in forming process.

The present invention also provides a kind of methods of producing ethylene by ethanol dehydration, wherein using catalyst of the invention.This hair Bright catalyst is ethylene reaction produced especially suitable for the dehydration that low-concentration ethanol aqueous solution is raw material, and ethanol water concentration is 5wt% ~40wt%.The method of the producing ethylene by ethanol dehydration can use fixed-bed process, and reaction condition is as follows: mass space velocity 0.5 h^-1~12.0 h^-1, 180 DEG C ~ 400 DEG C of reaction temperature.

Catalyst of the present invention uses the silica support of bigger serface, and the addition of auxiliary agent iron can be improved silica load Acidity in the acidity of body, especially duct, and hydrogenation is played jointly with auxiliary agent nickel, the catalytic polyol in autoclave And/or furfural liquid-phase hydrogenatin, mainly there are two aspect effects: one is the liquid alkane that polyalcohol and/or furfural liquid-phase hydrogenatin generate Hydrocarbon adsorbs on a catalyst support, can effectively block the duct of carrier, the heteropoly acid ammonium of subsequent load is made to be distributed in carrier On outer surface；On the other hand, polyalcohol and/or furfural liquid-phase hydrogenatin can generate carbon distribution on carrier, can be to a certain extent Weaken the acidity of carrier, reduces the quantity of support acidity position absorption ammonia, heteropoly acid is made mainly to react with ammonium salt organic acid life At ammonium heteropoly acids, it is evenly dispersed in carrier surface to facilitate ammonium heteropoly acids, and can be removed through subsequent high-temperature roasting Carbon deposit is stated, effectively remains this Component Vectors acidic site in this way.The catalyst that the method for the present invention obtains not only has low temperature living Property is high, selectivity is good, the characteristics of having strong anti-carbon capacity, and stability is good.

Specific embodiment

Below with reference to embodiment, the present invention is described in detail.In the present invention, wt% is mass fraction.

Embodiment 1

(1) preparation of carrier:

It weighs and 15.2g ferric nitrate and 205g citric acid is made into mixed solution, 145.8g cetyl front three is then added After being completely dissolved, 302mL tetraethyl orthosilicate is added in mixed solution for base ammonium bromide, 2 h is stirred, then at 70 DEG C Stirring, by gel in 12 h of aged at room temperature, 8 h is then dried at 110 DEG C, are roasted after compression molding at 580 DEG C at gel 3 h are burnt, iron-containing silica support is obtained, wherein the molar ratio of cetyl trimethylammonium bromide and silica is 0.3, lemon The molar ratio of acid and silica is 0.8.31.1 g nickel nitrates are dissolved in deionized water, are added to the iron-containing silica support of 77g In, stirring is evaporated to solution at 70 DEG C, by obtained solid in 110 DEG C of dry 8.0 h, then in 400 DEG C of 3.0 h of roasting, The catalyst carrier of iron content and nickel, support is made are as follows: specific surface area is 490 m²0.60 mL/g of/g, Kong Rongwei, average hole Diameter is 4.9 nm.

(2) preparation of catalyst:

The catalyst carrier of iron content and nickel is added in autoclave, 400 DEG C are warming up under hydrogen atmosphere, 4h is handled under 0.3MPa, is down to reaction temperature, the sorbitol solution that 400g mass concentration is 20% is added, then adjusts hydrogen pressure Power reacts 3h at 260 DEG C, after reaction, catalyst filtration is come out, dried at room temperature to carrier surface aneroid to 3MPa Phase；It is then added in the aqueous solution containing 37.0g citric acid, stirring to solution is evaporated at 40 DEG C；Obtained material is added 10min is impregnated into sal volatile, it is dry at 40 DEG C after filtering；It is then added to the aqueous solution containing 15.6g phosphotungstic acid In, stirring to solution is evaporated at 70 DEG C；By obtained solid in 110 DEG C of dry 8.0 h, then in 500 DEG C of 3.0 h of roasting, (NH is made₄)_0.5H_2.5PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 8wt%, Fe₂O₃Content is 3wt%, (NH₄)_0.5H_2.5PW₁₂O₄₀Content is 15wt%.

(3) catalyst characterization:

It is taken a little in the surrounding in catalyst granules section and centre, elemental analysis is carried out to each point by SEM, the results showed that Heteropoly acid ammonium salt content at surrounding each point is substantially suitable, and ammonium heteropoly acids are not detected in intermediate each point, illustrates using this side The catalyst of method preparation, the dispersion that ammonium heteropoly acids have had on catalyst surface, and be not impregnated with into duct.

(4) evaluation of catalyst:

Evaluating catalyst carries out in atmospheric fixed bed tubular reactor, and raw material is 20wt% ethanol water, mass space velocity 4 h^-1, 240 DEG C of reaction temperature.Before reaction, catalyst is in N₂In 400 DEG C of 2 h of activation under protection, then it is down to reaction temperature and opens After beginning reaction 4 hours, product is analyzed by gas-chromatography, is calculated ethanol conversion and ethylene selectivity, be the results are shown in Table 1.

Embodiment 2

(1) preparation of carrier:

It weighs and 20.2g ferric nitrate and 105.7g citric acid is made into mixed solution, 200g cetyl front three is then added After being completely dissolved, 250mL tetraethyl orthosilicate is added in mixed solution for base ammonium bromide, 2 h is stirred, then at 70 DEG C Stirring, by gel in 12 h of aged at room temperature, 8 h is then dried at 110 DEG C, are roasted after compression molding at 600 DEG C at gel 3 h are burnt, iron-containing silica support is obtained, wherein the molar ratio of cetyl trimethylammonium bromide and silica is 0.5, lemon The molar ratio of acid and silica is 0.5.38.9 g nickel nitrates are dissolved in deionized water, are added to the iron-containing silica support of 70g In, stirring is evaporated to solution at 70 DEG C, by obtained solid in 110 DEG C of dry 8.0 h, then in 400 DEG C of 3.0 h of roasting, The catalyst carrier of iron content and nickel, property is made are as follows: specific surface area is 510 m²0.64 mL/g of/g, Kong Rongwei, average Kong Zhi Diameter is 5.0 nm.

(2) preparation of catalyst:

The catalyst carrier of iron content and nickel is added in autoclave, 400 DEG C are warming up under hydrogen atmosphere, 4h is handled under 0.3MPa, is down to reaction temperature, the furfuryl aldehyde solution that 400g mass concentration is 20% is added, then adjusts Hydrogen Vapor Pressure To 3MPa, 3h is reacted at 150 DEG C, after reaction, catalyst filtration is come out, and is dried at room temperature to carrier surface aneroid Phase；It is then added in the aqueous solution containing 56.0g citric acid, stirring to solution is evaporated at 40 DEG C；Obtained material is added 10min is impregnated into sal volatile, it is dry at 40 DEG C after filtering；It is then added to the aqueous solution containing 20.7g phosphotungstic acid In, stirring to solution is evaporated at 70 DEG C；By obtained solid in 110 DEG C of dry 8.0 h, then in 470 DEG C of 3.0 h of roasting, (NH is made₄)_0.7H_2.3PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 10wt%, Fe₂O₃Content is 4wt%, (NH₄)_0.7H_2.3PW₁₂O₄₀Content is 20wt%.

(3) evaluation of catalyst:

Evaluating catalyst carries out in atmospheric fixed bed tubular reactor, and raw material is 20wt% ethanol water, mass space velocity 5 h^-1, 240 DEG C of reaction temperature.Before reaction, catalyst is in N₂In 400 DEG C of 2 h of activation under protection, then it is down to reaction temperature and opens After beginning reaction 4 hours, product is analyzed by gas-chromatography, is calculated ethanol conversion and ethylene selectivity, be the results are shown in Table 1.

Embodiment 3

(1) preparation of carrier:

25.3g ferric nitrate and 62.4g citric acid are made into mixed solution, 316g cetyl trimethyl bromination is then added After being completely dissolved, 246mL tetraethyl orthosilicate is added in mixed solution for ammonium, stir 2 h, then stirred at 70 DEG C to At gel, by gel in 12 h of aged at room temperature, then dry 8 h at 110 DEG C, in 650 DEG C of 3 h of roasting after compression molding, Iron-containing silica support is obtained, wherein the molar ratio of cetyl trimethylammonium bromide and silica is 0.8, citric acid and oxygen The molar ratio of SiClx is 0.3.46.7 g nickel nitrates are dissolved in deionized water, are added in the iron-containing silica support of 63g, 70 Stirring to solution is evaporated at DEG C, and by obtained solid in 110 DEG C of dry 8.0 h, then in 400 DEG C of 3.0 h of roasting, iron content is made With the catalyst carrier of nickel, property are as follows: specific surface area is 530 m²0.68 mL/g of/g, Kong Rongwei, average pore diameter 5.1 nm。

(2) preparation of catalyst:

The catalyst carrier of iron content and nickel is added in autoclave, 400 DEG C are warming up under hydrogen atmosphere, 4h is handled under 0.3MPa, is down to reaction temperature, the sorbitol solution that 400g mass concentration is 20% is added, then adjusts hydrogen pressure Power reacts 2h at 300 DEG C, after reaction, catalyst filtration is come out, dried at room temperature to carrier surface aneroid to 3MPa Phase；It is then added in the aqueous solution containing 70.6g citric acid, stirring to solution is evaporated at 40 DEG C；Obtained material is added 10min is impregnated into sal volatile, it is dry at 40 DEG C after filtering；It is then added to the aqueous solution containing 25.9g phosphotungstic acid In, stirring to solution is evaporated at 70 DEG C；By obtained solid in 110 DEG C of dry 8.0 h, then in 520 DEG C of 3.0 h of roasting, (NH is made₄)_0.2H_2.8PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, (NH₄)_0.2H_2.8PW₁₂O₄₀Content is 25wt%.

(3) evaluation of catalyst:

Evaluating catalyst carries out in atmospheric fixed bed tubular reactor, and raw material is 20wt% ethanol water, mass space velocity 8 h^-1, 240 DEG C of reaction temperature.Before reaction, catalyst is in N₂In 400 DEG C of 2 h of activation under protection, then it is down to reaction temperature and opens After beginning reaction 4 hours, product is analyzed by gas-chromatography, is calculated ethanol conversion and ethylene selectivity, be the results are shown in Table 1.

Embodiment 4

In embodiment 3, cetyl trimethylammonium bromide is changed to 628g P123, with embodiment 3, gained is urged for remaining Agent is (NH₄)_0.2H_2.8PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, (NH₄)_0.2H_2.8PW₁₂O₄₀Content is 25wt%, P123 and SiO₂Molar ratio be 0.1.Support are as follows: specific surface area 512 m²0.71 mL/g of/g, Kong Rongwei, average pore diameter are 5.5 nm.

The evaluation of catalyst the results are shown in Table 1 with embodiment 1, ethanol conversion and ethylene selectivity.

Embodiment 5

In embodiment 3, phosphotungstic acid is changed to silico-tungstic acid, 10min is impregnated in sal volatile and is changed to inhale

Attached 10v% NH₃/ Ar gaseous mixture 10min, with embodiment 3, gained catalyst is (NH for remaining₄)_0.2H_3.8SiW₁₂O₄₀/ NiO-Fe₂O₃-SiO₂, wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, (NH₄)_0.2H_3.8SiW₁₂O₄₀Content is 25wt%.

Embodiment 6

(1) carrier prepared by selection example 3:

(2) preparation of catalyst:

The catalyst carrier of iron content and nickel is added in autoclave, 400 DEG C are warming up under hydrogen atmosphere, 4h is handled under 0.3MPa, is down to reaction temperature, the sorbitol solution that 400g mass concentration is 20% is added, then adjusts hydrogen pressure Power reacts 2h at 300 DEG C, after reaction, catalyst filtration is come out, dried at room temperature to carrier surface aneroid to 3MPa Phase；It is then added in the aqueous solution containing 66.1g citric acid, stirring to solution is evaporated at 40 DEG C；Obtained material is added 10min is impregnated into sal volatile, it is dry at 40 DEG C after filtering；It is then added to the aqueous solution containing 29.0g phosphotungstic acid In, stirring to solution is evaporated at 70 DEG C；By obtained solid in 110 DEG C of dry 8.0 h, then in 520 DEG C of 3.0 h of roasting, (NH is made₄)_0.2H_2.8PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, (NH₄)_0.2H_2.8PW₁₂O₄₀Content is 28wt%.

(3) evaluation of catalyst:

Evaluating catalyst carries out in atmospheric fixed bed tubular reactor, and raw material is 20wt% ethanol water, mass space velocity 9h^-1, 240 DEG C of reaction temperature.Before reaction, catalyst is in N₂In 400 DEG C of 2 h of activation under protection, then it is down to reaction temperature and opens After beginning reaction 4 hours, product is analyzed by gas-chromatography, is calculated ethanol conversion and ethylene selectivity, be the results are shown in Table 1.

Embodiment 7

Catalyst is made according to embodiment 3, has carried out the stabilization of 100 h to catalyst according to the evaluation condition of embodiment 3 Property evaluation experimental, ethanol conversion and ethylene selectivity the results are shown in Table 2.

Comparative example 1

In embodiment 3, nickeliferous and iron carrier is added directly into the aqueous solution containing 25.9g phosphotungstic acid, 70 Stirring to solution is evaporated at DEG C；By obtained solid in 110 DEG C of dry 8.0 h, then in 350 DEG C of 3.0 h of roasting, it is made H₃PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, H₃PW₁₂O₄₀Content is 25wt%。

The evaluation of catalyst the results are shown in Table 1 with embodiment 3, ethanol conversion and ethylene selectivity.

Comparative example 2

The silica support 75g of the nickeliferous and iron prepared in embodiment 3 is added in C6 alkane solvent, 10min is impregnated, Then it filters, dries to carrier surface at 40 DEG C without liquid phase；It is then added in the aqueous solution containing 70.6g citric acid, Stirring to solution is evaporated at 70 DEG C；Obtained material, which is added in sal volatile, impregnates 10min, does at 60 DEG C after filtering It is dry；It is then added in the aqueous solution containing 25.9g phosphotungstic acid, stirring to solution is evaporated at 70 DEG C；Obtained solid is existed (NH is made then in 520 DEG C of 3.0 h of roasting in 110 DEG C of 8.0 h of drying₄)_0.2H_2.8PW₁₂O₄₀/NiO-Fe₂O₃-SiO₂Catalyst, Wherein NiO content is 12wt%, Fe₂O₃Content is 5wt%, (NH₄)_0.2H_2.8PW₁₂O₄₀Content is 25wt%.

Comparative example 3

Catalyst is made according to comparative example 1, has carried out the stabilization of 100 h to catalyst according to the evaluation condition of embodiment 3 Property evaluation experimental, ethanol conversion and ethylene selectivity the results are shown in Table 2.

The conversion ratio and selectivity of 1 each catalyst of table

	Conversion ratio, wt%	Selectivity, wt%
			Embodiment 1	97.3	98.2
Embodiment 2	97.4	98.1
			Embodiment 3	98.5	98.5
Embodiment 4	98.8	98.9
			Embodiment 5	98.4	98.6
Embodiment 6	98.5	98.6
			Comparative example 1	95.0	95.2
Comparative example 2	95.4	96.3

2 stability test evaluation result of table

	Conversion ratio, wt%	Selectivity, wt%
			Embodiment 7	98.3	98.4
Comparative example 3	82.0	82.2

By Tables 1 and 2 result as it can be seen that activity, selectivity and the stability of catalyst of the present invention are urged significantly better than comparative example Agent.

Claims

1. a kind of preparation method of heteropoly acid ammonium salt form catalyst, the heteropoly acid ammonium salt form catalyst include active component, contain The carrier of auxiliary agent, active component are that ammonium heteropoly acids are shown in formula (1), and carrier is the silica of nickel containing auxiliary agent and iron；With catalyst On the basis of weight, the content of ammonium heteropoly acids is 3% ~ 35%, and auxiliary agent is in terms of oxide, and the content of nickel oxide is 3% ~ 18%, three oxygen The content for changing two iron is 1% ~ 10%, and the content of silica is 37% ~ 93%；

H_m(NH₄)_nYX₁₂O₄₀(1)

Wherein X represents W or Mo, and Y represents Si or P；When Y represents Si, m+n=4, n value is 0.1 ~ 1.0；When Y represents P, m+ N=3, n value are 0.1 ~ 1.0；

The preparation method of the catalyst, comprising:

(2) step (1) resulting catalyst carrier is added in autoclave, reduction treatment is carried out to it using hydrogen；

(3) polyalcohol and/or furfuryl aldehyde solution are added in autoclave, then adjust Hydrogen Vapor Pressure to 2~4MPa, 100~ 0.5~5.0h is reacted at 300 DEG C；

(4) product that step (3) reaction obtains is through filtering, through drying to sample surfaces without liquid phase, before obtaining catalyst under low temperature Body A；

(5) the catalyst precarsor A that step (4) obtains is added in aqueous solutions of organic acids, heating stirring to solution is evaporated, and is obtained Catalyst precarsor B；

(6) the catalyst precarsor B that step (5) obtains is added in the alkaline solution containing ammonium, through filtering, at 40 DEG C ~ 90 DEG C It is dry；Or the catalyst precarsor B that step (5) obtains is adsorbed into ammonia at 40 DEG C ~ 90 DEG C, obtain catalyst precarsor C；

(7) aqueous solution of heteropoly acid being added in the catalyst precarsor C that step (6) obtains, heating stirring to solution is evaporated, then Through dry and roasting to get catalyst.

2. preparation method described in accordance with the claim 1, it is characterised in that: on the basis of the weight of catalyst, ammonium heteropoly acids Content be 12% ~ 30%, the content of nickel oxide is 5% ~ 15%, and the content of di-iron trioxide is 2% ~ 7%, and the content of silica is 48%~81%。

3. preparation method described in accordance with the claim 1, it is characterised in that: in the catalyst, ammonium heteropoly acids are distributed in The outer surface of carrier.

4. preparation method described in accordance with the claim 1, it is characterised in that: the property of the silica support of the nickel containing auxiliary agent and iron Matter is as follows: specific surface area is 400 ~ 750 m²0.50 ~ 0.80 mL/g of/g, Kong Rongwei, average pore diameter are 4.1 ~ 6.2 nm.

5. preparation method described in accordance with the claim 1, it is characterised in that: the silica of nickel containing auxiliary agent and iron carries in step (1) Body the preparation method is as follows:

6. preparation method according to claim 5, it is characterised in that: in step A, the iron containing compounds are nitric acid One of iron, ferric sulfate, iron chloride are a variety of；The organic acid is one of citric acid, tartaric acid, malic acid or more Kind, SiO in the organic acid and carrier₂Molar ratio be 0.1 ~ 1.2.

7. preparation method according to claim 5, it is characterised in that: in step A, the template is cetyl front three Base ammonium bromide, hexadecyltrimethylammonium chloride, lauryl sodium sulfate, triblock polymer P123, triblock polymer One of F127, triblock polymer F108, polyethylene glycol that molecular weight is 1000 ~ 10000 or a variety of, described templates With SiO in carrier₂Molar ratio be 0.01 ~ 1.2；In step B, the silicon source is one of ethyl orthosilicate, silica solution Or it is a variety of.

8. preparation method according to claim 5, it is characterised in that: in step C, the drying condition is as follows: 90 DEG C ~ 120 DEG C of dry 3h ~ 12h, roasting condition are as follows: in 300 DEG C ~ 800 DEG C roasting 2 h ~ 6 h.

9. preparation method according to claim 5, it is characterised in that: in step D, need after the dipping by dry and Roasting process, drying condition are as follows: 90 DEG C ~ 120 DEG C dry 3h ~ 12h, roasting condition are as follows: 300 DEG C ~ 500 DEG C 2 h of roasting ~ 6 h。

10. preparation method described in accordance with the claim 1, it is characterised in that: in step (5) or step (7), the heating is stirred The temperature mixed is 40 DEG C ~ 90 DEG C.

11. preparation method described in accordance with the claim 1, it is characterised in that: in step (7), the drying condition is as follows: 90 DEG C ~ 120 DEG C dry 3h ~ 12h, the roasting condition are as follows: in 300 DEG C ~ 550 DEG C roasting 2 h ~ 6 h.

12. preparation method described in accordance with the claim 1, it is characterised in that: in step (2), the reduction treatment process is such as Under: catalyst carrier is warming up to 300 DEG C~600 DEG C under hydrogen atmosphere, 4h~8h is handled at 0.1MPa~0.5MPa.

13. preparation method described in accordance with the claim 1, it is characterised in that: in step (3), the polyalcohol is C5~C10 One of polyalcohol is a variety of；The mass concentration of polyalcohol and/or furfuryl aldehyde solution is 5%~35%, polyalcohol and/or furfural The mass ratio of additional amount and step (1) resulting catalyst carrier is 2:1 ~ 10:1.

14. preparation method described in accordance with the claim 1, it is characterised in that: in step (3), polyalcohol and/or furfuryl aldehyde solution Mass concentration is 5%~30%, and the mass ratio of the additional amount and step (1) resulting catalyst carrier of polyalcohol and/or furfural is 3:1~10:1。

15. preparation method described in accordance with the claim 1, it is characterised in that: in step (5), the organic acid is citric acid, wine One of stone acid, malic acid or a variety of, SiO in the organic acid and carrier₂Molar ratio be 0.05 ~ 0.50.

16. preparation method described in accordance with the claim 1, it is characterised in that: in step (6), catalyst that step (5) is obtained Precursor B, which is added in the alkaline solution containing ammonium, to be impregnated, and dip time is the min of 5 min ~ 30；It is urged what step (5) obtained Agent precursor B adsorbs ammonia, and adsorption time is the min of 5 min ~ 30；In step (6), the alkaline solution containing ammonium is ammonia One of water, sal volatile, ammonium bicarbonate soln are a variety of.

17. preparation method described in accordance with the claim 1, it is characterised in that: in step (7), the heteropoly acid be phosphotungstic acid, One of silico-tungstic acid, phosphomolybdic acid are a variety of.

18. a kind of heteropoly acid ammonium salt form catalyst, it is characterised in that: using any preparation method system of claim 1-17 ?.

19. a kind of method of producing ethylene by ethanol dehydration, it is characterised in that using the catalyst described in claim 18.

20. according to the method for claim 19, it is characterised in that: the raw material of ethanol dehydration uses concentration for 5wt% ~ 40wt% Ethanol water, using fixed-bed process, reaction condition is as follows: 0.5 h of mass space velocity^-1~12.0 h^-1, reaction temperature 180 ℃~400℃。