CN106925279B

CN106925279B - Fe-based selective hydrogenation catalyst, preparation method and application thereof

Info

Publication number: CN106925279B
Application number: CN201511032668.5A
Authority: CN
Inventors: 梁玉龙; 车春霞; 韩伟; 张峰; 苟尕莲; 钱颖; 景喜林; 蔡小霞; 张忠东; 谷丽芬; 郭珺; 景丽; 杨珊珊
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2020-05-08
Anticipated expiration: 2035-12-31
Also published as: CN106925279A

Abstract

The invention relates to a Fe system selective hydrogenation catalyst, wherein the active component of the catalyst comprises 2-15 wt% of Fe, 0-2 wt% of X, and X is selected from one or more of K, La and Ce. The rest is oxygen element and carrier. The specific surface of the catalyst is 10-300 m²The pore volume is 0.2 to 0.65 ml/g. The catalyst of the present invention can be used in C_2～3Selective hydrogenation of acetylene, propyne and propadiene (MAPD) in the cracked fraction. The catalyst has mild hydrogenation activity, excellent olefin selectivity, high olefin increment, good operation elasticity, low green oil generation amount and good long-period running performance. And the catalyst cost is far lower than that of the noble metal Pd catalyst.

Description

Fe-based selective hydrogenation catalyst, preparation method and application thereof

Technical Field

The invention relates to a Fe system selective hydrogenation catalyst, a preparation method and application thereof, which are used for preparing ethylene and propylene by selective hydrogenation of acetylene, propyne (MA) and Propadiene (PD) contained in a fraction cracked by carbon dioxide.

Background

Ethylene and propylene are one of the most important basic raw materials in the petrochemical industry, and are mostly prepared by steam cracking of petroleum hydrocarbons (such as ethane, propane, butane, naphtha, light diesel oil and the like) as monomers for synthesizing various polymers. The C2 fraction mainly containing ethylene obtained by the method also contains 0.5 to 2.5 percent (mole fraction) of acetylene. The presence of acetylene complicates the polymerization process of ethylene and deteriorates the polymer properties. When polyethylene is produced by a high pressure process, there is a risk of explosion due to the accumulation of acetylene; in addition, the presence of acetylene also reduces the activity of the polymerization catalyst and increases the catalyst consumption when producing polyethylene. Therefore, acetylene in ethylene must be reduced to a certain value or less to be used as a monomer for synthesizing a high polymer.

Currently, a noble metal Pd-based hydrogenation catalyst is generally used in industry to selectively remove acetylene in a C2 fraction and propyne (MA) and propadiene (Pd) in a C3 fraction. The patent US4404124 prepares a selective hydrogenation catalyst with a palladium shell layer distribution as an active component by a step-by-step impregnation method, and can be applied to selective hydrogenation of carbon dioxide and carbon three fractions to eliminate acetylene in ethylene and propadiene in propylene. US5587348 uses alumina as carrier, regulates the action of promoter silver and palladium, and adds alkali metal and chemically bonded fluorine to prepare excellent carbon dioxide hydrogenation catalyst. The catalyst has the characteristics of reducing the generation of green oil, improving the selectivity of ethylene and reducing the generation amount of oxygen-containing compounds. US5519566 discloses a process for preparing silver and palladium catalysts by wet reduction, by adding organic or inorganic reducing agents to the impregnation solution, silver and palladium bi-component selective hydrogenation catalysts are prepared.

Because of using noble metal Pd as active component, the catalyst cost is high, and because the noble metal catalyst activity is high, there are certain problems in the aspects of device start-up stability, operation flexibility and long-period operation performance of the catalyst. The development of a low-cost and excellent-performance carbon dioxide hydrogenation catalyst system is always the aim of scientific research personnel in the field.

CN2005800220708.2 discloses a selective hydrogenation catalyst for acetylene and diolefin in light olefin raw material, which is composed of a first component selected from copper, gold and silver and a second component selected from nickel, platinum, palladium, iron, cobalt, ruthenium and rhodium, and in addition, the catalyst also includes at least one inorganic salt and oxide selected from zirconium, lanthanide and alkaline earth metal mixture. The catalyst forms a fluorite structure after being calcined, used or regenerated. The total content of the catalyst oxide is 0.01-50%, and the preferred roasting temperature is 700-850 ℃. The addition of a third oxide, modified alumina or silica support, helps to increase catalyst selectivity and activity, selectivity after regeneration. The technology still takes copper, gold, silver, palladium and the like as active components and takes nickel, platinum, palladium, iron, cobalt, ruthenium, rhodium and the like as auxiliary components, and the regeneration performance of the catalyst is improved by modifying the oxide of the carrier.

CN102218323A discloses a hydrogenation catalyst for unsaturated hydrocarbons, the active component is a mixture of 5-15% of nickel oxide and 1-10% of other metal oxides, the other metal oxides can be one or more of molybdenum oxide, cobalt oxide and iron oxide, and in addition, 1-10% of an auxiliary agent is also included. The technology is mainly used for hydrogenating and converting ethylene, propylene, butylene and the like in the tail gas of the coal-to-liquid industry into saturated hydrocarbon, and has good deep hydrogenation capacity. The technology is mainly used for the total hydrogenation of ethylene, propylene, butylene and the like in various industrial tail gases rich in CO and hydrogen, and is not suitable for the selective hydrogenation of alkyne and dialkene.

ZL201080011940.0 discloses an ordered cobalt-aluminum and iron-aluminum intermetallic compound as acetylene hydrogenation catalyst, and the intermetallic compound is selected from the group consisting of CoAl and CoAl₃、Co₂Al₅、Co₂Al₉、o-Co₄Al₁₃、h-Co₄Al₁₃、m-Co₄Al₁₃、FeAl、FeAl₂、Fe₃Al、Fe₂Al₅、Fe₄Al₁₃Group (d) of (a). Among them, Fe is preferred₄Al₁₃And o-Co₄Al₁₃. The intermetallic compound is prepared by a hot melting method in solid chemistry. The hydrogenation performance of the catalyst is tested in a quartz tube furnace, the reaction temperature is 473K, and after the stable reaction is carried out for 20 hours, o-Co₄Al₁₃The catalyst has acetylene conversion rate up to 62%, ethylene selectivity up to 71%, and Fe₄Al₁₃The acetylene conversion rate on the catalyst reaches 40%, and the ethylene selectivity reaches 75%. The technology is used for preparing intermetallic compounds under the condition of high temperature, is used for selective hydrogenation of acetylene, has low acetylene conversion rate and high reaction temperature, and is not beneficial to industrial application. And the catalyst is prepared by a hot melting method, and the conditions are harsh.

In summary, the selective hydrogenation of low carbon alkynes and dienes mainly adopts noble metal catalysts, and a great deal of work is carried out on the research and development of non-noble metal catalysts, but the selective hydrogenation is far away from the industrial application. In order to solve the problem, the invention provides a Fe hydrogenation catalyst and a preparation method thereof.

Disclosure of Invention

The invention aims to provide an Fe-based catalyst for selective hydrogenation of alkyne and dialkene in a carbon-reduced fraction. The catalyst of the invention can selectively hydrogenate a small amount of acetylene, propyne (MA) and Propadiene (PD) contained in the cracking atmosphere to convert the acetylene, the propyne (MA) and the Propadiene (PD) into ethylene and propylene. The method can also be used for refining reaction of ethylene and propylene, completely removing trace acetylene, propyne (MA) and Propadiene (PD) contained in raw materials of ethylene and propylene, and producing polymerization-grade raw materials.

In order to achieve the purpose, the invention adopts the following technical scheme: the non-noble metal catalyst with the high-temperature-resistant inorganic oxide as the carrier comprises 2-15% of Fe (calculated by 100% of the mass of the catalyst), preferably 4-10%, and 0-2% of X, wherein X is selected from one or more of K, La and Ce, and preferably 0.2-1.5%; the specific surface of the catalyst is 10-300 m²The preferred concentration is 30-170 m/g²The pore volume is 0.2-0.65 ml/g, preferably 0.30-0.63 ml/g, wherein Fe is loaded on the carrier by dipping, calcined at 300-700 ℃, reduced at 250-500 ℃ by atmosphere containing hydrogen, and the Fe element in the catalyst is α -Fe₂O₃The form exists.

The Fe element in the catalyst can be Fe or Fe₂O₃、Fe₃O₄Various forms such as FeO, etc., but α -Fe among them₂O₃The Fe content in the form is higher than that in the other forms, and preferably, it is 50% or more of the total Fe mass.

The carrier of the invention is a high-temperature resistant inorganic oxide, the technical key point of the invention is that the catalyst contains Fe, and after roasting and reduction processes, the carrier has no special requirements, such as one or more of alumina, silica, zirconia, magnesia and the like, but the most common carrier is also the best alumina or alumina carrier, the alumina carrier is a composite carrier of alumina and other oxides, wherein, the alumina accounts for more than 50 percent of the mass of the carrier, such as a composite of alumina and oxides of silica, zirconia, magnesia and the like, the best is an alumina-zirconia composite carrier, wherein, the alumina content is more than 60 percent, the alumina can be theta, α, gamma or a mixture of a plurality of crystal forms, the best is α -Al₂O₃Or containing α -Al₂O₃Mixed crystal form alumina of (1).

The invention also provides a preparation method of the catalyst, which comprises the following steps:

the catalyst is obtained by preparing Fe precursor aqueous solution and X precursor aqueous solution, respectively impregnating the carrier, respectively aging, drying and roasting, or impregnating the carrier with mixed solution thereof, then aging, drying and roasting, and finally reducing.

The preferred conditions in the preparation method of the invention are:

the dipping temperature is 30-60 ℃, the dipping time is 10-60 min, the pH value of the dipping solution is 1.5-5.0, the aging temperature is 30-60 ℃, the aging time is 30-120 min, the roasting temperature is 400-500 ℃, and the roasting time is 180-300 min.

In the present invention, the drying is preferably temperature-programmed drying, and the drying temperature program is set as follows:

in the present invention, the calcination, i.e. the activation process, is preferably temperature programmed calcination, and the calcination temperature program is set as follows:

the catalyst can be prepared by adopting any one impregnation mode of isometric impregnation, excessive impregnation, surface spray impregnation, vacuum impregnation and multiple impregnation.

The preparation method of the catalyst provided by the invention comprises the following specific steps:

(1) and measuring the water absorption of the carrier and then weighing the carrier.

(2) Accurately weighing a certain amount of Fe precursor (recommending soluble nitrate, chloride or sulfate) according to the load, preparing an impregnation solution according to the water absorption rate of the carrier and an impregnation method, adjusting the pH value of the impregnation solution to 1.5-5.0 according to requirements, and heating the solution to 30-60 ℃ for later use.

(3) When an isometric immersion or spray immersion method is adopted, the weighed carrier can be placed into a rotary drum, the rotating speed of the rotary drum is adjusted to be 25-30 r/min, the carrier is completely turned over, the prepared immersion liquid at the temperature of 30-60 ℃ is poured or sprayed onto the carrier at a certain speed, and the carrier is loaded for 5-10 min.

When an excessive impregnation method is adopted, the weighed carrier is placed in a container, then the prepared impregnation solution with the temperature of 30-60 ℃ is added, the container is quickly shaken, so that heat emitted in the adsorption process is quickly released, the active component is uniformly loaded on the carrier, and standing is carried out for 5-10 min so that the surface active component and the active component in the solution compete for adsorption balance.

When a vacuum impregnation method is adopted, the weighed carrier is placed in a cyclone evaporator, the vacuum is pumped, impregnation liquid with the temperature of 30-60 ℃ is added for impregnation for 5-10 min, and the carrier is heated in a water bath until the surface of the carrier is completely dried.

(4) Transferring the impregnated catalyst into a container, and aging the catalyst for 30-120 min at 25-60 ℃.

(5) Filtering out excessive solution after impregnation, and then drying in an oven by adopting a temperature programming method, wherein the drying temperature programming is as follows:

(6) roasting and activating the dried catalyst in a muffle furnace or a tubular furnace, wherein the roasting temperature-rising program comprises the following steps:

the catalyst X component is loaded by adopting the same steps, the roasting temperature is 300-700 ℃, preferably 400-500 ℃, the two components can also be prepared into a mixed solution, and the mixed solution is dipped on the surface of the carrier at one time according to the steps.

The reduction of the invention means that before the catalyst is used, hydrogen-containing gas is required for reduction, H₂The content is preferably 10-50%, the reduction temperature is preferably 250-500 ℃, the reduction time is 240-360 min, and the volume space velocity is 100-500 h^-1The reduction pressure is 0.1-0.8 MPa; the recommended condition is to use N₂+H₂The mixed gas is carried out at 300-400 ℃ under the micro-positive pressure conditionThe reduction time is preferably 240-360 min, and the volume airspeed is preferably 200-400 h^～1The reduction pressure is preferably 0.1 to 0.5 MPa.

The active component of the catalyst is mainly Fe, the catalyst is a non-noble metal catalyst, even cobalt, nickel, molybdenum and tungsten are not contained, the cost is greatly reduced, and the cost of the catalyst is far lower than that of a noble metal Pd catalyst.

The Fe element in the catalyst can be Fe or Fe₂O₃、Fe₃O₄And the forms of the FeO and the Fe exist, and one or more of K, La and Ce is recommended to be added into the active composition containing the Fe, so that the formation and dispersion of an activated phase of the catalyst are facilitated, the stability of the activated phase is facilitated, and the selectivity and the coking resistance of the catalyst are improved.

The activation temperature of the catalyst in the invention is related to the active composition, content and carrier of the catalyst, α -Fe is formed after the activation process₂O₃Fe in a form which is stable and the activation temperature cannot be too high, and on the other hand, the activation degree determines the reduction condition of the catalyst, and α -Fe is still used in the catalyst provided by the invention₂O₃Fe in the form of Fe is a main component, and excessive reduction can influence the effect of the catalyst and the selectivity and is easy to coke.

The catalyst of the invention has the following beneficial effects:

(1) the catalyst of the invention has far lower cost than noble metal Pd catalyst, the used raw materials are harmless and easy to obtain, and the preparation method is simple and is easy to realize technically.

(2) The catalyst has mild hydrogenation activity and good operation elasticity, and is suitable for application in industrial devices.

(3) The catalyst of the invention has good selectivity, and the olefin increment is higher than that of a noble metal catalyst.

(4) The green oil generation amount of the catalyst is far lower than that of a noble metal catalyst, and the catalyst is suitable for long-period operation of the catalyst.

The Fe system selective hydrogenation catalyst is most suitable for selective hydrogenation removal of acetylene, propyne and propadiene contained in an ethylene atmosphere.

Drawings

FIG. 1 shows the XRD spectrum (with the carrier background removed) of the catalyst of example 3;

FIG. 2 is the XRD spectrum (with the carrier background subtracted) of the catalyst of comparative example 2;

FIG. 3 is the XRD spectrum (with the carrier background subtracted) of the catalyst of comparative example 5;

XRD measurement conditions:

german Bruker D8ADVANCE X-ray diffractometer

Tube voltage: 40kV current 40mA

Scanning: step size of 0.02 degree, frequency of 0.5s, scanning range of 4-120 degree, temperature of 25 degree C

Cu K α 1 wavelength, diffraction angle 2 theta on abscissa and diffraction intensity on ordinate

Symbolic illustration in fig. 1:

● is α -Fe₂O₃▲ is Fe₃O₄，

Is CeO;

the symbols in fig. 2 illustrate:

● is α -Fe₂O₃▲ is Fe₃O₄■ is LaFeO₃；

The symbols in fig. 3 illustrate:

▲ is Fe₃O₄Xxx is Ce, ★ is α -Fe;

as can be seen in FIG. 1, the Fe in the catalyst is mainly α -Fe₂O₃The form appears, and the relative content is 7.6%;

as can be seen in FIG. 2, the second component La in the catalyst, mainly combined with iron oxide to form LaFeO₃The auxiliary component and the active component are sintered, so that the distribution and the structure of the active component are damaged, and the activity of the catalyst is reduced;

α -Fe was not included in FIG. 3₂O₃In the phase, Fe mainly appears in the form of simple substance α -Fe, the relative content is 8.92%, and the third component appears in the form of simple substance Ce.

Detailed Description

The analysis and test method comprises the following steps:

specific surface area: GB/T-5816

Pore volume: GB/T-5816

Content of Fe oxide in different crystal forms: XRD

The content of active components in the catalyst is as follows: atomic absorption method

The conversion and selectivity in the examples were calculated according to the following formulas:

acetylene conversion (%) -100 × △ acetylene/inlet acetylene content

Ethylene selectivity (%) - () 100 × △ ethylene/△ acetylene

Example 1

Weighing 100ml of clover type α -alumina carrier with the diameter of 4.5 multiplied by 4.5mm, placing the carrier in a 1000ml beaker, taking ferric nitrate, heating and dissolving the ferric nitrate in 60ml of deionized water, adjusting the pH value to be 2.5, keeping the temperature of an impregnation solution at 50 ℃, impregnating the surface of the carrier with equal volume, quickly shaking the carrier for impregnation for 6min, standing for 30min until the carrier is in equilibrium of adsorption, completely sealing the mouth of the beaker by a preservative film, aging in a water bath at the temperature of 60 ℃ for 30min, and then placing in an oven according to the procedures:

transferring the catalyst into an evaporating dish, and activating the catalyst in a muffle furnace by adopting a programmed heating method, wherein the activating program comprises the following steps:

weighing lanthanum nitrate, and impregnating according to the preparation steps. The catalyst properties are shown in table 1.

The evaluation method comprises the following steps:

the performance of the catalyst is evaluated on a 10ml micro-reaction device, the catalyst is crushed in a mortar, 3ml of the catalyst is sieved by a sieve of 10-20 meshes, and the sieved catalyst is diluted to 5ml by glass beads of 20 meshes and filled.

The catalyst is firstly reduced by 40 percent of hydrogen and 60 percent of nitrogen, the reduction temperature is 320 ℃, the pressure is 0.5MPa, and the reduction time is 4 hours.

Reaction conditions are as follows:volume space velocity 8000h^-1The pressure is 1.5MPa, and the reaction temperature is 80 ℃.

The reaction raw material gas adopts standard gas and comprises the following components:

the physical properties of the prepared catalyst are shown in Table 1, and the reaction results are shown in Table 2.

Example 2

NaAlO is added at 50 deg.C₂Solution and ZrCl₄The solution is stirred and mixed, then is neutralized by nitric acid solution, is stirred for 10 hours, and is coprecipitated to generate uniform Al-Zr particles. The resultant was filtered, and Na contained therein was washed with deionized water⁺And Cl^-And (3) ionizing, adding a proper amount of polyvinyl alcohol with the mass concentration of 15% as a pore-forming agent, and kneading and molding. Drying at 130 ℃ for 2h, and roasting at 650 ℃ for 4h to obtain the Zr-Al composite carrier, wherein the mass ratio of alumina to zirconia in the carrier is 4: 1.

100ml of the composite carrier is weighed and placed in a 1000ml big beaker. Heating and dissolving ferric chloride and potassium chloride in 100ml of deionized water, adjusting the pH value to be 2.0, soaking the carrier in excess at the temperature of 80 ℃, shaking a beaker for soaking for 10min, filtering out excessive soaking liquid, aging the catalyst in a water bath at the temperature of 60 ℃ for 50min, and then drying in an oven according to the following procedures:

the catalyst properties are shown in table 1.

The catalyst evaluation was carried out in the same manner as in example 1, and the catalyst was reduced with 30% hydrogen at a reduction temperature of 340 ℃ under a pressure of 0.5MPa for a reduction time of 4 hours.

Reaction conditions are as follows: volume space velocity 8000h^-1The pressure is 1.5MPa, and the reaction temperature is 80 ℃.

the reaction results are shown in table 2.

Example 3

Weighing 100ml of spherical α -alumina carrier with the diameter of 1.5mm, dissolving ferric nitrate in 40ml of deionized water, adjusting the pH value to 3.0, keeping the temperature of an impregnation solution at 40 ℃, spraying the impregnation solution on the carrier by a spray can, loading the carrier in a rotary drum for 10min to uniformly load active components, controlling the loading process to be finished within 6min, and then loading the carrier in an oven according to the following procedures:

to obtain a leached catalyst.

And (3) dissolving cerium nitrate, spraying and soaking the dissolved cerium nitrate on the surface of the first-soaked catalyst, drying and roasting to obtain the final catalyst by adopting the same method in the first step. And (3) drying procedure:

and (3) roasting procedure:

XRD analysis of the reduced catalyst is shown in figure 1.

The catalyst properties are shown in table 1.

The catalyst was reduced with 20% hydrogen at 360 ℃ under 0.5MPa for 4 hours, using the same method as in example 1.

the reaction results are shown in table 2.

Example 4

50ml of spherical alumina-titania support of 2.0mm diameter were weighed out and placed in a rotary evaporator. Ferric nitrate was dissolved in 15ml of deionized water and the pH was adjusted to 3.5 for further use. Opening a vacuum pumping pump of the rotary evaporator to a vacuum degree of 0.1mmHg, then slowly adding the prepared impregnation liquid from a feeding port, finishing adding after 5min, carrying out rotary evaporation under the heating of water bath at 60 ℃ until the flowing moisture on the surface of the catalyst completely disappears, finishing loading, moving the loaded catalyst out of the rotary evaporator, and carrying out the following procedures in an oven:

in a muffle furnace according to:

to obtain a leached catalyst.

And (3) taking lanthanum nitrate, impregnating according to the same method, drying, and roasting to obtain the final catalyst. And (3) drying procedure:

and (3) roasting procedure:

the catalyst properties are shown in table 1.

The catalyst was reduced with 15% hydrogen at 380 ℃ under 0.5MPa for 4 hours, using the same method as in example 1.

Example 5

A catalyst was prepared by weighing 100ml of an alumina carrier having a diameter of 4.0mm by the same method as in example 3. The activation temperature was 650 ℃.

The catalyst properties are shown in table 1.

The catalyst is reduced by 25 percent hydrogen at the temperature of 700 ℃, the pressure of 0.5MPa and the activation time of 4 h.

Evaluation was carried out in the same manner as in example 1.

The reaction raw material gas adopts standard gas (ethane balance gas) and has the following composition:

Example 6

The commercial pseudo-boehmite, silica gel, zirconium oxychloride powder and extrusion aid are mixed according to the weight ratio of alumina: silicon oxide: uniformly mixing zirconium oxide in a ratio of 8:1:3, extruding the mixture on a strip extruding machine for forming, drying the mixture at 120 ℃, and roasting the mixture in a muffle furnace at 550 ℃ for 3 hours to obtain the Zr-Si-Al composite oxide carrier.

50ml of the prepared Zr-Si-Al carrier was weighed out, and a catalyst was prepared by the same method as in example 4.

The catalyst properties are shown in table 1.

The catalyst is activated at high temperature in a tubular furnace, wherein the activation atmosphere is 45% of hydrogen and 55% of nitrogen, the temperature is 450 ℃, the pressure is 0.5MPa, and the activation time is 4 hours. The physical properties of the prepared catalyst are shown in Table 1.

Evaluation was carried out in the same manner as in example 1.

The reaction raw material gas adopts standard gas (ethane is balance gas) and has the following composition:

the reaction results are shown in table 2.

Example 7

A catalyst was prepared in the same manner as in example 1 using alumina having a particle diameter of 4.0mm as a carrier, and activated at 450 ℃.

Before the catalyst is used, the catalyst is reduced by 20 percent hydrogen at the temperature of 450 ℃, the pressure of 0.5MPa and the activation time of 4 h. Evaluation was carried out in the same manner as in example 1.

Reaction conditions are as follows: volume space velocity 8000h^-1The pressure is 2.5MPa, and the reaction temperature is 50 ℃.

Comparative example 1

Taking an alumina carrier with phi of 4.0mm and a specific surface of 4.5m²The pore volume was 0.32 ml/g. The method comprises the steps of adopting an isometric impregnation method, impregnating a silver nitrate solution onto a carrier in an isometric manner, aging, drying and roasting to obtain a primary impregnated catalyst, then dissolving palladium chloride, impregnating in an isometric manner, aging, drying and roasting to obtain a final catalyst (PAH-01 hydrogenation catalyst of petrochemical research institute). The catalyst contains Pd 0.050% and AgThe amount was 0.20%.

The catalyst is reduced by hydrogen for 160min at 100 ℃, the pressure is 0.5MPa, and the volume space velocity of the hydrogen is 100h^-1。

Evaluation of feed gas composition:

Comparative example 2

The catalyst was prepared in the same manner as in example 1 using alumina of Φ 4.0mm as a carrier, and the catalyst activation temperature was 850 ℃.

The catalyst is reduced by 25 percent hydrogen at the temperature of 450 ℃ and under the pressure of 0.5MPa for 4 hours. The XRD diffraction pattern of the reduced catalyst is shown in figure 2.

Evaluation was carried out in the same manner as in example 1.

Comparative example 3

A catalyst was prepared by the same method as in example 1 by using alumina having a particle diameter of 4.0mm as a carrier, and activated at 450 ℃.

The catalyst is reduced by 35 percent hydrogen, the temperature is 450 ℃, the pressure is 0.5MPa, and the activation time is 4 h.

Evaluation was carried out in the same manner as in example 1.

Reaction conditions are as follows: volume space velocity 8000h^-1Pressure of1.5MPa, and the reaction temperature is 80 ℃.

Comparative example 4

The same catalyst as in example 1 was used, and the catalyst was activated at 450 ℃ and then directly started without reduction with hydrogen.

Evaluation was carried out in the same manner as in example 1.

Comparative example 5

The same catalyst as in example 1 was used and activated at 450 ℃.

The catalyst is reduced in a tubular furnace under the atmosphere of 30% hydrogen and 55% nitrogen at 850 ℃, the pressure of 0.5MPa and the activation time of 4 h. The XRD diffraction pattern of the reduced catalyst is shown in figure 3.

The physical properties of the prepared catalyst are shown in Table 1.

Evaluation was carried out in the same manner as in example 1.

the reaction results are shown in table 2.

TABLE 1 Carrier and catalyst Properties

TABLE 2 catalyst pairs C_2-3Selective hydrogenation of cracked material

Note: acetylene and ethylene are polymerized to produce n-butene, which is further polymerized to produce "green oil", and the amount of n-butene produced is generally used to characterize the amount of catalyst green oil "produced during the analysis.

Claims

1. A Fe system selective hydrogenation catalyst is a non-noble metal catalyst, and is characterized in that the catalyst contains 2-15% of Fe and 0.2-1.5% of X by 100% of the mass of the catalyst, wherein the X is selected from one or more of K, La and Ce; the specific surface of the catalyst is 10-300 m²The pore volume is 0.2-0.65 mL/g, wherein Fe is loaded on the carrier by dipping, calcined at 300-700 ℃, reduced at 250-500 ℃ by atmosphere containing hydrogen, and in the catalyst, Fe is α -Fe₂O₃The morphology exists.

2. The Fe-based selective hydrogenation catalyst according to claim 1, characterized in that: the catalyst contains 4-10% of Fe by 100% of the mass of the catalyst; the specific surface of the catalyst is 30-170 m²The pore volume is 0.30 to 0.63 mL/g.

3. According to claim 1The Fe-based selective hydrogenation catalyst is characterized in that α -Fe is contained in the catalyst₂O₃The Fe in the form accounts for more than 50% of the total weight of the Fe.

4. The Fe-based selective hydrogenation catalyst according to claim 1, wherein the carrier is alumina or an alumina-based carrier, the alumina-based carrier is a composite carrier of alumina and other oxides, wherein the alumina accounts for more than 50% of the mass of the carrier, and the alumina is in a form of theta, α, gamma or a mixture of a plurality of crystal forms thereof.

5. The Fe-based selective hydrogenation catalyst according to claim 4, wherein: the alumina carrier is a composite of alumina, silica, zirconia and magnesia, wherein the content of alumina is more than 60%.

6. The Fe-based selective hydrogenation catalyst according to claim 5, wherein the alumina-based carrier is an alumina-zirconia composite carrier, and the alumina is α -Al₂O₃Or containing α -Al₂O₃Mixed crystal form alumina of (1).

7. The Fe system selective hydrogenation catalyst according to claim 1, wherein the impregnation means is equal volume impregnation, excess impregnation, surface spray impregnation, vacuum impregnation or multiple impregnation.

8. A method for preparing the Fe-based selective hydrogenation catalyst according to any one of claims 1 to 7, characterized in that: the preparation process of the catalyst comprises the following steps: preparing impregnation liquid containing Fe precursor water solution and X precursor water solution, respectively impregnating the carrier, respectively aging, drying and roasting or impregnating the carrier with mixed solution thereof, then aging, drying and roasting, and finally reducing to obtain the catalyst.

9. The method according to claim 8, wherein the catalyst is prepared by the following steps: the dipping temperature is 30-60 ℃, the dipping time is 10-60 min, the pH value of the dipping solution is 1.5-5.0, the aging temperature is 30-60 ℃, the aging time is 30-120 min, the roasting temperature is 300-700 ℃, and the roasting time is 180-300 min.

10. The method according to claim 9, wherein the catalyst is prepared by the following steps: the roasting temperature is 400-500 ℃.

11. The method according to claim 8, wherein the catalyst is prepared by the following steps: the drying conditions were:

12. the method according to claim 8, wherein the catalyst is prepared by the following steps: the roasting is temperature programmed roasting, and the roasting temperature program is set as follows:

13. the method according to claim 8, wherein the catalyst is prepared by the following steps: catalyst reduction means that the calcined catalyst is reduced with a hydrogen-containing gas, H, before the catalyst is used₂The volume content is 10-50%, the reduction temperature is 250-500 ℃, the reduction time is 240-360 min, and the volume airspeed is 100-500 h^-1And the reduction pressure is 0.1-0.8 MPa.

14. The method according to claim 13, wherein the catalyst is prepared by: the conditions for the reduction of the catalyst are as follows: with N₂+H₂The mixed gas is carried out at 300-400 ℃ and the volume airspeed of 200-400 h^-1The reduction pressure is 0.1-0.5 MPa.

15. The use of the Fe-based selective hydrogenation catalyst according to claim 1, wherein: the Fe selective hydrogenation catalyst is used for selective hydrogenation removal of acetylene, propyne and propadiene contained in an ethylene atmosphere.