CN106928012B

CN106928012B - Acetylene removal method by using carbon dioxide post-hydrogenation process

Info

Publication number: CN106928012B
Application number: CN201511032411.XA
Authority: CN
Inventors: 苟尕莲; 钱颖; 胡晓丽; 谷丽芬; 车春霞; 韩伟; 张峰; 梁玉龙; 刘俊涛; 郭珺; 杨珊珊; 何崇慧
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2019-12-10
Anticipated expiration: 2035-12-31
Also published as: CN106928012A

Abstract

A method for removing alkyne in a post-hydrogenation carbon dioxide process is characterized in that a Ti-Fe-Ni selective hydrogenation catalyst is filled in a reactor, a carrier is a high-temperature-resistant inorganic oxide, the catalyst contains 2-12% of Fe, 0.2-1.5% of Ti and 0.5-1.8% of Ni by weight of 100% of the catalyst, the specific surface of the catalyst is 10-200 m ²/g, and the pore volume is 0.2-0.63 ml/g, wherein Fe is loaded on the carrier in an impregnation mode and is prepared by roasting and hydrogen atmosphere reduction, and in the catalyst, Fe mainly exists in an alpha-Fe ₂ O ₃ form and contains a FeNi phase.

Description

acetylene removal method by using carbon dioxide post-hydrogenation process

Technical Field

the invention relates to a method for removing alkyne by hydrogenation after carbon dioxide, in particular to a method for removing alkyne by hydrogenation in a hydrogenation process after carbon dioxide by using a Ti-Fe-Ni catalyst.

Background

Polymer grade ethylene production is the tap of the petrochemical industry, and polymer grade ethylene and propylene are the most basic raw materials for downstream polymerization plants. The selective hydrogenation of acetylene has very important influence on the ethylene processing industry, the selectivity of the catalyst is excellent except ensuring that the content of the acetylene at the outlet of a hydrogenation reactor reaches the standard, the ethylene can be generated into ethane as little as possible, and the catalyst has important significance for improving the ethylene yield of the whole process and the economic benefit of a device.

The cracked carbon-dioxide fraction contains acetylene with a mole fraction of 0.5-2.5%, and a small amount of acetylene in ethylene reduces the activity of a polymerization catalyst and deteriorates the physical properties of a polymer when polyethylene is produced, so that the acetylene content in ethylene must be reduced to a certain limit before the ethylene can be used as a monomer for synthesizing a high polymer. Acetylene separation and conversion is therefore one of the important processes in the ethylene plant scheme.

The catalytic selective hydrogenation in the ethylene device comprises front hydrogenation and back hydrogenation, wherein the front hydrogenation and the back hydrogenation of acetylene refer to that the hydrogenation reactor is positioned in front of the demethanizer and is front hydrogenation, and the hydrogenation reactor is positioned behind the demethanizer and is back hydrogenation relative to the position of the demethanizer. The post hydrogenation is a sequential separation process, and the process has the advantages of multiple control means in the hydrogenation process, difficult temperature runaway and convenient operation, but has the defects of easy coking of the catalyst and frequent regeneration of the catalyst. The reason for this is that, in the hydrogenation process, since the amount of hydrogen added is small, the hydrodimerization reaction of acetylene easily occurs to produce 1, 3-butadiene, and further to produce an oligomer having a relatively wide molecular weight, commonly referred to as "green oil". The green oil is adsorbed on the surface of the catalyst and further forms coke to block the pore channels of the catalyst, so that the activity and the selectivity of the catalyst are reduced.

at present, the hydrogenation after the carbon dioxide is mainly carried out by adopting a two-section or three-section reactor series connection process, and a device with lower space velocity or low alkyne content can adopt a two-section reactor series connection. At present, the industrial device mainly adopts a three-section reactor series connection process.

the post-hydrogenation feed generally consists of: 1.0-2.2% (v) acetylene, 65-85% ethylene and the balance ethane, and hydrogen is added after metering.

The reaction is exothermic, but the temperature rise is relatively low, and the maximum temperature rise of a single reactor is different from 30-60 ℃ according to the airspeed, so that an adiabatic reactor is basically adopted.

For two-stage reactors, the first stage reactor is required to convert more than 70% of acetylene, and the second stage reactor converts the residual acetylene to a content of less than 1 μ L/L.

For the device with higher space velocity or higher acetylene content, a three-section reactor process is generally adopted, the first section converts about 50 percent, the other two sections convert the residual acetylene, and the acetylene content at the outlet of the three-section reactor is less than 1 mu L/L.

The amount of hydrogen is related to the acetylene content and the process adopted. For the three-stage reactor process, the hydrogen/acetylene ratio of the first stage reactor is generally 0.8-1.2, the hydrogen/acetylene ratio of the second stage reactor is generally 1-1.5, and the hydrogen/acetylene ratio of the third stage reactor is generally 1.5-3.

For the two-stage reactor process, the hydrogen/acetylene ratio in the first stage reactor is generally 1-1.5, and the hydrogen/acetylene ratio in the second stage reactor is generally 2-4.

The reaction mechanism is as follows:

Main reaction C₂H₂+H₂→C₂H₄ △H＝-175.7kJ/mol (1)

side reactions

C₂H₄+H₂→C₂H₆ △H＝-138.1kJ/mol (2)

C₂H₂+2H₂→C₂H₆ (3)

2C₂H₂+H₂→C₄H₆ (4)

C₂H₂+nC₂H₂+H₂→C_2n+2H_2n+4 (5)

in these applications, reaction (1) is the hydrogenation of acetylene and reactions (2) and (3) are the hydrogenation of ethylene. Reaction (4) is a hydrodimerization of acetylene, which contributes significantly to the production of green oil, and reaction (5) is a general reaction formula for producing green oil.

Among these reactions, only the reaction (1) is a desired reaction, and the others are undesired reactions.

US5856262 reports a process for preparing low acidity palladium catalysts on potassium hydroxide (or barium, strontium, rubidium hydroxide, etc.) modified silica as support, at a space velocity of 3000h^-1And under the conditions that the inlet temperature is 35 ℃, the inlet acetylene mole fraction is 0.71 percent, and the mole ratio of the acetylene to the hydrogen is 1.43, the outlet acetylene mole fraction is less than 0.1 mu L/L, and the selectivity of the ethylene reaches 56 percent. In the patent US4404124, alumina is used as a carrier, and a promoter silver is added to react with palladium, so that the carbon dioxide hydrogenation catalyst with excellent performance is prepared. The catalyst has the characteristics of reducing the ethane generation amount, inhibiting acetylene adsorbed on the surface of the catalyst from carrying out partial hydrodimerization reaction, inhibiting the generation of 1, 3-butadiene, reducing the generation of green oil, improving the ethylene selectivity and reducing the generation amount of oxygen-containing compounds, and is widely applied to the ethylene industry. However, the above catalysts are prepared by impregnation method, and are limited by the preparation method, the metal dispersion degree is only about 30%, and the catalyst performance has many defects, and further improvement is still needed.

The traditional Pd-Ag bimetallic selective hydrogenation catalyst is prepared by adopting an aqueous solution impregnation method. When the sub-leaching method is adopted, one component is more enriched on the surface of the carrier, the other component is enriched on the outer surface, and only part of metal atoms are mutually permeated to form an alloy structure. Meanwhile, by adopting a co-immersion method, due to different interaction between precursors of two metal ions and a carrier and surface tension and solvation, uniform loading of the two components is difficult to form, and only an alloy structure can be partially formed. When the catalyst is applied to selective hydrogenation of carbon dioxide fraction, the selectivity is good at the initial stage of reaction, the selectivity is continuously reduced along with the extension of the operation time, regeneration is needed after the catalyst is generally operated for 3-6 months, and the economic loss is large.

CN201110086174.0 forms a polymer coating layer on the surface of the carrier in a certain thickness by adsorbing a specific polymer compound on the carrier, and the compound with a functional group reacts with the polymer to enable the polymer to have the functional group capable of complexing with the active component, and the active component is ensured to be orderly and highly dispersed by the complexing reaction of the active component on the functional group on the surface of the carrier. By adopting the method, the carrier adsorbs specific high molecular compounds, and the high molecular compounds are chemically adsorbed with the high molecular compounds through the hydroxyl groups of the alumina, and the amount of the high molecular compounds adsorbed by the carrier is limited by the number of the hydroxyl groups of the alumina; the functional polymer and Pd have weak complexing effect, sometimes the loading capacity of the active component can not meet the requirement, and part of the active component remains in the impregnation liquid, so that the cost of the catalyst is increased; the method for preparing the carbon dioxide hydrogenation catalyst also has the defect of complicated process flow.

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 novel Ti-Fe-Ni hydrogenation catalyst and a preparation method thereof.

Disclosure of Invention

The invention aims to provide a method for removing alkyne in a carbon dioxide post-hydrogenation process. In particular to a Ti-Fe-Ni selective hydrogenation catalyst which selectively hydrogenates acetylene contained in the tower top effluent from a deethanizer and completely converts the acetylene into ethylene without loss of the ethylene.

The acetylene removing method of the post-carbon hydrogenation process of the invention comprises the steps of enabling a refined ethylene material at the top of an ethylene rectifying tower to enter an adiabatic reactor for selective hydrogenation to remove trace acetylene therein, and reactingThe Ti-Fe-Ni selective hydrogenation catalyst containing non-noble metal is filled in the device, based on 100 mass of the catalyst, the catalyst contains 2-12% of Fe, 0.2-1.5% of Ti, preferably 0.5-1%, 0.5-1.8% of Ni, preferably 0.8-1.2%, and the specific surface of the catalyst is 10-200 m²A ratio of 30 to 100 m/g is preferred²The pore volume is 0.2-0.63 ml/g, preferably 0.35-0.49 ml/g; wherein Fe is loaded on a carrier in an impregnation mode, roasted at 300-700 ℃, and reduced by atmosphere containing hydrogen at 200-500 ℃; in the catalyst, Fe is mainly alpha-Fe₂O₃exists in a form and contains a FeNi phase. Selecting the hydrogenation reaction conditions: the inlet temperature of the reactor is 40-100 ℃, the reaction pressure is 1.5-2.5 MPa, and the gas volume space velocity is 2000-10000H < -1 >, H₂/C₂H₂The volume ratio is 1-20. Preferred hydrogenation conditions are: the inlet temperature of the hydrogenation reactor is 45-55 ℃, the reaction pressure is 1.8-2.2 MPa, the gas volume space velocity is 5000-8000H < -1 >, and the H₂/C₂H₂The volume ratio is 1.2-5.

The acetylene removing method adopts the hydrogenation catalyst, the carrier is a high-temperature-resistant inorganic oxide, and the technical key point of the method is that the catalyst contains Fe, and the catalyst is roasted and reduced, so that the carrier has no special requirement, such as one or more of alumina, silica, zirconia, magnesia and the like. However, alumina or alumina-based carriers, which are composite carriers of alumina and other oxides, in which alumina accounts for 50% or more of the mass of the carrier, are also preferred, and for example, alumina and oxides such as silica, zirconia, magnesia, etc., and alumina-zirconia composite carriers, in which the alumina content is 60% or more, are also preferred. The alumina can be theta, alpha, gamma type or their mixture of multiple crystal forms, preferably alpha-Al₂O₃or containing alpha-Al₂O₃Mixed crystal form alumina of (1).

The preparation process of the Fe catalyst adopted by the alkyne removing method comprises the following steps:

The catalyst is obtained by preparing impregnation liquid of Fe precursor aqueous solution and Ti and Ni precursor aqueous solution, impregnating the carrier respectively, aging respectively, drying, roasting, reducing or impregnating the carrier with mixed solution thereof, aging, drying, roasting and finally reducing.

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

The dipping temperature is 30-60 ℃, the loading time is 10-60 min, the pH value of the dipping solution is 1.5-5.0, the temperature is 20-60 ℃, 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 a temperature-raising 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 Ni component of the catalyst can be singly soaked by adopting the steps or can be prepared into a mixed solution with Fe and then is soaked together according to the steps; the Ti component is loaded by adopting the same steps, and the roasting temperature is 300-700 ℃, preferably 400-500 ℃.

The Fe element in the catalyst can be Fe or Fe₂O₃、Fe₃O₄FeO, but in which alpha-Fe is present in various forms₂O₃The 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. In the present invention, it is recommended to add Ni to the iron-containing active composition by treatmentA FeNi phase is formed, which is beneficial to the activation of hydrogen and improves the activity of the catalyst; in the present invention, it is recommended to add TiO to the iron-containing active component₂The method is beneficial to the formation and dispersion of the catalyst active phase, and is beneficial to the stability of the active phase, 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, and alpha-Fe is formed after the activation process₂O₃Fe in a form, and is relatively stable, and the activation temperature cannot be too high; on the other hand, the degree of activation determines the reduction conditions of the catalyst, and the catalyst provided by the invention still uses alpha-Fe₂O₃fe 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 active component of the catalyst is mainly Fe, and the catalyst can be a non-noble metal catalyst, even can not contain cobalt, molybdenum and tungsten, so that the cost is greatly reduced, and the cost of the catalyst is far lower than that of a noble metal Pd catalyst.

The catalyst reduction of the present invention means that the calcined catalyst is reduced with a hydrogen-containing gas, H, before the catalyst is used₂The volume content is preferably 10-50%, the reduction temperature is 200-500 ℃, the reduction time is 240-360 min, and the volume airspeed is 100-500 h^-1The reduction pressure is 0.1-0.8 MPa; with the preferred proviso that N is used₂+H₂Reducing the mixed gas at the reduction temperature of 300-400 ℃ at a volume airspeed of 200-400 h^-1The reduction pressure is preferably 0.1 to 0.5 MPa. The process is usually carried out before the selective hydrogenation reaction, and is preferably carried out outside the reactor, i.e., outside the selective hydrogenation reaction apparatus.

Due to the beneficial effect of the catalyst, the adiabatic bed reactor can be a two-section or three-section series adiabatic bed hydrogenation reactor. When the hydrogenation reactor is a three-section series adiabatic bed reactor, the inlet temperature of the first-section reactor is 40-50 ℃, the volume ratio of hydrogen to acetylene is 0.8-1.2, the inlet temperature of the second-section reactor is 45-55 ℃, the volume ratio of hydrogen to acetylene is 1-1.5, the inlet temperature of the three-section reactor is 50-60 ℃, and the volume ratio of hydrogen to acetylene is 1.5-3.0. When the hydrogenation reactor is a two-stage adiabatic bed reactor, the inlet temperature of the first stage reactor is 40-50 ℃, the volume ratio of hydrogen to acetylene is 1-1.5, the inlet temperature of the second stage reactor is 50-60 ℃, and the volume ratio of hydrogen to acetylene is 2-4.

According to the method for removing acetylene by hydrogenation after carbon dioxide, the hydrogenation raw material is from the top effluent of a deethanizer in the hydrogenation process after carbon dioxide, and the raw material composition mainly comprises: 0.98-2.2% of acetylene, 11.2-30.3% of ethane and 65.0-85.0% of ethylene.

By adopting the alkyne-removing method, the catalyst has moderate reaction activity, good operation elasticity and good ethylene selectivity, and the green oil generation amount is far lower than that of a noble metal catalyst.

drawings

FIG. 1 is a flow diagram of a carbon dioxide selective hydrogenation process employing a sequential separation scheme. 1-oil wash column; 2-water washing tower; 3-alkaline washing tower; 4-a dryer; 5-a demethanizer; 6-deethanizer; 7-a carbon dioxide hydrogenation adiabatic bed reactor; 8-heat exchanger.

FIG. 2 is the XRD spectrum (minus the carrier alpha-Al) of the catalyst in example 3₂O₃Background).

FIG. 3 is the XRD spectrum (minus the carrier alpha-Al) of the catalyst of comparative example 2₂O₃Background).

FIG. 4 is the XRD spectrum (minus the carrier α -Al) of the catalyst of comparative example 5₂O₃background).

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 Ka 1 wavelength, diffraction angle 2 theta on abscissa and diffraction intensity on ordinate

The symbols in fig. 2 illustrate:

● is alpha-Fe₂O₃A, tangle-solidup is FeNi, and t is Ti₂O。

The symbols in fig. 3 illustrate:

● is alpha-Fe₂O₃Tangle-solidup is FeNi, diamond-solid is anatase.

Symbolic illustration in fig. 4:

^ is alpha-Fe, ■ is Fe₃O₄A t is Ti₂O, and a-solidup is Ni.

As can be seen in FIG. 2, the Fe in the catalyst is mainly alpha-Fe₂O₃the relative content is 8.10%, and an FeNi phase appears at the same time.

As can be seen in fig. 3, Ti in the catalyst sinters with iron oxide, an anatase crystal phase appears, distribution and structure of active components are destroyed, and the catalyst activity decreases.

In FIG. 4, Fe mainly appears in the form of simple substance alpha-Fe, the relative content is 8.92%, and a small amount of Fe exists₃O₄And (4) forming.

Detailed Description

The analysis and test method comprises the following steps:

comparison table: GB/T-5816

Pore volume: GB/T-5816

Content of Fe oxide in different crystal forms: XRD

The content of active components of the catalyst is as follows: GB/T1537-94

Acetylene conversion (C)

Selectivity (S) for hydrogenation to ethylene

Example 1

Weighing cloverleaf clover type alumina carrier with phi of 4.5 multiplied by 4.5 mm. Taking ferric nitrate, heating and dissolving in 60ml of deionized water, adjusting the pH value to be 2.5, keeping the temperature of an impregnation liquid at 50 ℃, impregnating the surface of a carrier in an equal volume, rapidly turning over the carrier for impregnation for 6min, standing for 30min until adsorption is balanced, aging at 60 ℃ for 30min, and then placing in an oven according to the following procedures:drying the catalyst, activating by programmed heating methodThe method comprises the following steps: weighing lanthanum nitrate, and impregnating according to the preparation steps.

Before the catalyst is used, reducing the catalyst in a reducing furnace by using 40 percent of hydrogen and 60 percent of nitrogen at the reduction temperature of 450 ℃, under the pressure of 0.5MPa and for 4 hours. The hydrogenation scheme shown in figure 1 was used with the catalyst packed in an adiabatic bed reactor. The raw materials comprise:

C₂H₂：1.6％(Φ)，C₂H₄75.3％(Φ)，C₂H₆23.1％(Φ)。

reaction conditions are as follows: two sections of adiabatic bed reactors are connected in series for reaction, namely, the material at the outlet of the first section of reactor enters the second section of reactor. Each reactor section is provided with an independent gas distribution system.

Material gas space velocity: 2000h^-1The operating pressure is as follows: 2.5MPa, catalyst loading of each reactor: 50 ml. First stage reactor H₂/C₂H₂1.5: 1 (molar ratio); two-stage reactor H₂/C₂H₂3: 1 (molar ratio) and 200 hours are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

Example 2

At 50 ℃, a certain amount of NaAlO is added₂Solution 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 15% polyvinyl alcohol serving 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. The mass ratio of alumina to zirconia in the carrier was 4: 1.

The catalyst is prepared by alumina-zirconia composite carrier. Heating ferric chloride and potassium chloride to dissolve in deionized water, adjusting pH to 2.0, soaking at 80 deg.C, soaking on the carrier in excess amount,Shaking the beaker for 10min, filtering off the excess impregnation, aging the catalyst in a water bath at 60 ℃ for 50min, and then in an oven according to the procedure:Drying the catalyst, and activating the catalyst by adopting a programmed heating method, wherein the activating program comprises the following steps:

Before the catalyst is used, reducing the catalyst in a reducing furnace by using 30 percent of hydrogen and 60 percent of nitrogen at the reducing temperature of 550 ℃, under the pressure of 0.5MPa and for 4 hours. The hydrogenation scheme shown in figure 1 was used with the catalyst packed in an adiabatic bed reactor. The raw materials comprise:

C₂H₂：1.4％(Φ)，C₂H₄80.0％(Φ)，C₂H₆18.6％(Φ)。

Material gas space velocity: 5000h^-1The operating pressure is as follows: 2.2MPa, catalyst loading of each reactor: 50 ml. First stage reactor H₂/C₂H₂1.5: 1 (molar ratio); two-stage reactor H₂/C₂H₂4:1 (molar ratio) and 500 hours are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

Example 3

Spherical alumina with phi of 1.5mm is weighed to prepare the catalyst. Dissolving ferric nitrate in deionized water, adjusting the pH value to 3.0, keeping the temperature of the impregnation liquid at 40 ℃, spraying the carrier by a spraying pot, loading for 10min to uniformly load the active components, and then, in an oven, according to the following procedures: drying the catalyst, and activating the catalyst by adopting a programmed heating method, wherein the activating program comprises the following steps: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:

Before the catalyst is used, reducing the catalyst in a reducing furnace by using 20 percent hydrogen at the reducing temperature of 400 ℃ and under the pressure of 0.5MPa for 4 h. XRD analysis of the reduced catalyst is shown in figure 2. The hydrogenation scheme shown in figure 1 was used with the catalyst packed in an adiabatic bed reactor.

The post-hydrogenation process is adopted, and the reaction raw materials are as follows:

C₂H₂：2.2(v％)C₂H₄79.3(v％)，C₂H₆18.5(v％)。

Reaction conditions are as follows: the three-section bed adiabatic bed reactor series process is characterized in that the material at the outlet of the first-section reactor enters a second-section reactor, the material at the outlet of the second-section reactor enters a third-section reactor, and each section of reactor is provided with an independent gas distribution system.

Material gas space velocity: 7000h^-1The operating pressure is as follows: 1.8MPa, catalyst loading of each reactor: 50 ml. First stage reactor H₂/C₂H₂1: 1 (molar ratio); two-stage reactionH device₂/C₂H₂1.5: 1 (molar ratio); three-stage reactor H₂/C₂H₂3: 1 (molar ratio), the results are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

Example 4

The spherical alumina-titania carrier with phi of 2.0mm is weighed and placed in a vacuum impregnation device. Dissolving ferric nitrate in deionized water, and adjusting the pH value to 3.5 for later use. Opening a vacuum pumping pump of a vacuum impregnation device until the vacuum degree is 0.1mmHg, then slowly adding the prepared impregnation liquid from a feeding port, finishing the addition for 5min, evaporating at 60 ℃ until the flowing moisture on the surface of the catalyst completely disappears, finishing the loading, and putting the loaded catalyst in an oven according to the following procedures:Drying in a muffle furnace according to the following steps: And (4) roasting. To obtain a leached catalyst.

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

Before the catalyst is used, the catalyst is reduced by 15 percent hydrogen in a reducing furnace, the reducing temperature is 500 ℃, the pressure is 0.5MPa, and the reducing time is 4 hours. The hydrogenation scheme shown in figure 1 was used with the catalyst packed in an adiabatic bed reactor.

C₂H₂：2.2(v％)C₂H₄79.3(v％)，C₂H₆18.5(v％)。

Reaction conditions are as follows: the three-section bed adiabatic reactor series process is characterized in that the material at the outlet of the first-section reactor enters a second-section reactor, the material at the outlet of the second-section reactor enters a three-section reactor, and each section of reactor is provided with an independent gas distribution system.

Material gas space velocity: 10000h^-1the operating pressure is as follows: 1.5 MPa. First stage reactor H₂/C₂H₂1: 1 (molar ratio); two-stage reactor H₂/C₂H₂1.5: 1 (molar ratio); three-stage reactor H₂/C₂H₂3: 1 (molar ratio). The results are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

Weighing 100ml alumina carrier with 4.0mm diameter, and preparing the catalyst by the same method of the embodiment 3. The activation temperature was 650 ℃.

before the catalyst is used, the catalyst is reduced by 25 percent hydrogen in a reducing furnace, the temperature is 700 ℃, the pressure is 0.5MPa, and the reduction time is 4 h. The hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor.

C₂H₂：1.2(v％)C₂H₄80.3(v％)，C₂H₆18.5(v％)。

Example 6

The method comprises the following steps of mixing commercially available pseudo-boehmite, silica gel, zirconium oxychloride powder and extrusion aid 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. The catalyst was prepared by the same method as in example 4.

Before the catalyst is used, 45% hydrogen and 55% nitrogen are used in a reducing furnace, the temperature is 450 ℃, the pressure is 0.5MPa, and the activation time is 4 h. The hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor.

C₂H₂：2.2(v％)C₂H₄79.3(v％)，C₂H₆18.5(v％)。

Comparative example 1

LY-C2-02 catalyst for petrochemical institute, with particle diameter of phi 3.0mm and specific surface area of 20m²The pore volume is 0.30ml/g, and the bulk ratio is 0.75 g/ml. The catalyst has Pd content of 0.035% and Ag content of 0.085%.

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

The evaluation was carried out in the same manner as in example 1, the composition of the raw materials was the same as in example 1, and the reaction conditions were: airspeed of 6000h^-1The operating pressure is as follows: 2.0 MPa.

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

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 ℃.

Before the catalyst is used, the catalyst is reduced by 25 percent hydrogen in a reducing furnace, the temperature is 450 ℃, the pressure is 0.5MPa, and the activation time is 4 h. The hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor. The XRD diffraction pattern of the reduced catalyst is shown in figure 3.

The raw material composition is the same as that of example 2, and the reaction conditions are as follows: airspeed of 2000h^-1The operating pressure is as follows: 2.5 MPa.

Comparative example 3

Alumina of phi 4.0mm was weighed as a carrier, and the catalyst with low iron content was prepared by the same method as in example 1, and activated at 450 ℃.

Before the catalyst is used, the catalyst is reduced by 45 percent hydrogen in a reducing furnace, the temperature is 450 ℃, the pressure is 0.5MPa, and the activation time is 4 h. The hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor.

Evaluation was carried out by the same procedure as in example 3. The raw material composition is the same as that of example 3, and the reaction conditions are as follows: space velocity of 8000h^-1The operating pressure is as follows: 1.5 MPa.

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. The hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor.

Three sections of adiabatic reactors in series were used for evaluation, the raw material composition was the same as in example 1, and the reaction conditions were: airspeed of 3000h^-1The operating pressure is as follows: 2.0 MPa. The reaction results are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

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 hydrogenation scheme shown in figure 1 was used, and the catalyst was packed in an adiabatic bed reactor. The XRD diffraction pattern of the reduced catalyst is shown in figure 4.

three sections of adiabatic reactors in series were used for evaluation, the raw material composition was the same as in example 1, and the reaction conditions were: space velocity of 5000h^-1The operating pressure is as follows: 2.2 MPa. The reaction results are shown in Table 1, and the physical properties of the catalyst and the carrier are shown in Table 2.

TABLE 1 Process conditions and catalyst Properties

TABLE 2 catalyst Properties of the examples and comparative examples

The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for removing alkyne in a post-carbo-hydrogenation process is characterized in that in a post-carbo-hydrogenation ethylene device, a material flowing out of the top of a deethanizer is subjected to hydrogen preparation and then enters an adiabatic reactor for selective hydrogenation to remove acetylene, a Ti-Fe-Ni selective hydrogenation catalyst is filled in the reactor, a carrier is a high-temperature-resistant inorganic oxide, the catalyst contains Fe 2-12%, Ti 0.2-1.5% and Ni 0.5-1.8% by weight of 100% of the catalyst, and the specific surface of the catalyst is 10-200 m²The pore volume is 0.2-0.63 mL/g; wherein Fe is loaded on a carrier in an impregnation mode, roasted at 300-700 ℃, and reduced by atmosphere containing hydrogen at 200-500 ℃; in the catalyst, Fe is mainly alpha-Fe₂O₃Exists in a form and contains FeNi phase; selecting the hydrogenation reaction conditions: the inlet temperature of the reactor is 40-100 ℃, the reaction pressure is 1.5-2.5 MPa, and the gas volume space velocity is 2000-10000 h^-1，H₂/C₂H₂Is 1 to 20.

2. The alkyne removal method of claim 1, wherein the catalyst comprises α -Fe₂O₃The Fe in the form accounts for more than 50% of the total weight of the Fe.

3. The alkyne removal method as claimed in claim 1, wherein the carrier of the catalyst is alumina or a composite carrier of alumina and other oxides, the alumina accounts for more than 50% of the mass of the carrier in the composite carrier of alumina and other oxides, and the other oxides are silica, zirconia, magnesia or titania; the alumina is of the theta, alpha or gamma type.

4. The method of claim 1, wherein the impregnation is an equal volume impregnation, an excess impregnation, a surface spray impregnation, a vacuum impregnation or multiple impregnations.

5. The alkyne-removing method as claimed in claim 1, wherein the catalyst is obtained by preparing an aqueous solution of a Fe-containing precursor, an aqueous solution of a Ni precursor and an aqueous solution of a Ti precursor, impregnating the carriers respectively, aging respectively, drying, calcining or impregnating the carriers with a mixed solution thereof, aging, drying, calcining and then reducing.

6. The alkyne removal method of claim 5, wherein: 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.

7. The alkyne removal method of claim 5, wherein: the drying conditions were:

8. The alkyne removal method of claim 1 or 5, wherein: the roasting is temperature programmed roasting, and the roasting temperature program is set as follows:

9. the alkyne removal method of claim 1 or 5, wherein: 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 200-500 ℃, 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.

10. The alkyne removal method of claim 1, wherein: the hydrogenation reactor is a two-section series adiabatic bed reactor or a three-section series adiabatic bed reactor.

11. The alkyne removal method of claim 1, wherein: when three sections of adiabatic bed reactors are connected in series, the inlet temperature of the first section of reactor is 40-50 ℃, the volume ratio of hydrogen to acetylene is 0.8-1.2, the inlet temperature of the second section of reactor is 45-55 ℃, the volume ratio of hydrogen to acetylene is 1-1.5, the inlet temperature of the third section of reactor is 50-60 ℃, and the volume ratio of hydrogen to acetylene is 1.5-3.0.

12. The alkyne removal method of claim 1, wherein: when the hydrogenation reactor is formed by connecting two sections of heat-insulating bed reactors in series, the inlet temperature of the first section of reactor is 40-50 ℃, the volume ratio of hydrogen to acetylene is 1-1.5, the inlet temperature of the second section of reactor is 50-60 ℃, and the volume ratio of hydrogen to acetylene is 2-4.

13. The alkyne removal method as recited in claim 1, wherein the hydrogenation raw material is from the overhead of the deethanizer in the hydrogenation process after carbon two, and the volume composition of the raw material is mainly as follows: 0.98-2.2% of acetylene, 11.2-30.3% of ethane and 65.0-85.0% of ethylene.

14. The alkyne removal method as claimed in claim 1, wherein the catalyst contains 4 to 10% of Fe, 0.5 to 1% of Ti, and 0.8 to 1.2% of Ni, based on 100% of the mass of the catalyst, and the specific surface area of the catalyst is 30 to 100m²The pore volume is 0.35-0.49 mL/g; the selective hydrogenation reaction conditions are as follows: the inlet temperature of the reactor is 45-55 ℃, the reaction pressure is 1.8-2.2 MPa, and the gas volume space velocity is 5000-8000 h^-1，H₂/C₂H₂Is 1.2 to 5.

15. The alkyne removal method as recited in claim 3, wherein the composite support of alumina and other oxides is an alumina-zirconia composite support; the alumina is alpha-Al₂O₃。

16. the alkyne removal method as claimed in claim 6, wherein the calcination temperature is 400-500 ℃.

17. The alkyne removal method of claim 9, wherein the reduction conditions are N₂+H₂Reducing the mixed gas at the reduction temperature of 300-400 ℃ at a volume airspeed of 200-400 h^-1The reduction pressure is 0.1-0.5 MPa.