WO2021073640A1 - 一种碳二馏分炔烃选择加氢方法 - Google Patents

一种碳二馏分炔烃选择加氢方法 Download PDF

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WO2021073640A1
WO2021073640A1 PCT/CN2020/121914 CN2020121914W WO2021073640A1 WO 2021073640 A1 WO2021073640 A1 WO 2021073640A1 CN 2020121914 W CN2020121914 W CN 2020121914W WO 2021073640 A1 WO2021073640 A1 WO 2021073640A1
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catalyst
microemulsion
surfactant
hydrogenation
carbon
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PCT/CN2020/121914
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English (en)
French (fr)
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谭都平
王喆
路全能
李保江
李蓬勃
何磊
何超
张小宇
张生芳
沈健明
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中国石油天然气股份有限公司
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Priority claimed from CN201910988247.1A external-priority patent/CN112679301B/zh
Priority claimed from CN201910988249.0A external-priority patent/CN112675869B/zh
Priority claimed from CN201910990953.XA external-priority patent/CN112675870B/zh
Application filed by 中国石油天然气股份有限公司 filed Critical 中国石油天然气股份有限公司
Publication of WO2021073640A1 publication Critical patent/WO2021073640A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
    • B01J21/04—Alumina
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C11/00—Aliphatic unsaturated hydrocarbons
    • C07C11/02—Alkenes
    • C07C11/04—Ethylene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
    • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
    • C07C7/167—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation for removal of compounds containing a triple carbon-to-carbon bond
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the invention relates to a method for selective hydrogenation of carbon two fractions, in particular to a method for selective hydrogenation of carbon two fractions that maintains the selectivity and stability of the hydrogenation reaction.
  • Ethylene is one of the most important basic raw materials in the petrochemical industry.
  • the monomer ethylene used to synthesize various polymers most of it is steam cracked from petroleum hydrocarbons (such as ethane, propane, butane, naphtha, light diesel, etc.) be made of.
  • the ethylene-based C 2 fraction obtained by this method contains 0.5% to 2.3% (mole fraction) of acetylene. If there is more acetylene in ethylene, the polymerization process of ethylene will be complicated and the polymer performance will be deteriorated. Reduce polymerization catalyst activity and increase catalyst consumption. Therefore, the acetylene content in ethylene must be reduced below a certain value before it can be used as a monomer for the synthesis of high polymers.
  • the catalysts used are mainly precious metal catalysts with active components such as Pd, Pt, and Au.
  • the catalyst In order to ensure that the ethylene produced by the hydrogenation of acetylene and the original ethylene in the raw material will not continue to be hydrogenated to produce ethane, which will cause ethylene loss, the catalyst must have a higher hydrogenation selectivity to improve the economic benefits of the device.
  • C2 hydrogenation is an extremely important process in the petrochemical industry, which directly affects the stability of the entire ethylene plant.
  • the C2 hydrogenation process is mainly divided into two processes according to the hydrogenation materials and conditions. Since the location of the reactor determines the composition of the reaction materials, it is commonly named according to the relative position of the reactor and other parts, just like the previous addition. Hydrogenation and post-hydrogenation refer to the position of the acetylene hydrogenation reactor relative to the demethanizer. The hydrogenation reactor is located before the demethanizer for pre-hydrogenation, and the hydrogenation reactor is located after the demethanizer for post-hydrogenation.
  • the C2 post-hydrogenation process generally uses a three-stage hydrogenation reactor.
  • the total conversion rate of acetylene in the first stage reactor is 50-80%, hydrogen/acetylene is 1.0-1.4, and the total conversion rate of acetylene in the second-stage reactor is 40-20%.
  • Hydrogen/acetylene is 1.4-2.0, the residual acetylene is completely converted in the three-stage reactor, and the three-stage hydrogen/acetylene is 2.5-4.0.
  • the acetylene content at the outlet of the three-stage reactor is generally below 1ppm.
  • the hydrogenation dimerization of acetylene will occur to produce a series of oligomers with different molecular weights.
  • oligomers cannot flow with the gas phase material or move at a very low rate, and will adhere to the catalyst for a long time. The surface or enter the hole into the inside, causing the catalyst hole to be blocked. Due to the slow moving rate, they will gradually agglomerate. These oligomers themselves contain a large number of unsaturated bonds and can be further polymerized to form coking, which greatly reduces the activity selectivity of the catalyst.
  • the amount of hydrogenation dimerization product is closely related to the hydrogenation conditions.
  • the hydrogen/acetylene is low, the hydrogenation dimerization reaction of acetylene is very violent due to insufficient hydrogen; the coking rate of the catalyst will be very rapid.
  • the amount of green oil produced in the first stage reactor is also the largest.
  • the hydrogenation dimerization reaction at the entrance of the first stage reactor is the most intense, and part of the green oil is polymerized at the entrance of the first stage reactor. , So that the activity of this part of the catalyst declines rapidly.
  • the other part is the outlet of the reactor section. This is because as the hydrogenation reaction progresses, the hydrogen/alkynes become lower and lower, which makes the hydrogenation dimerization reaction rate rise again, and the increase in temperature will intensify the polymerization of green oil. .
  • Part of the C2 post-hydrogenation unit uses a two-stage hydrogenation process.
  • Part of the green oil produced in the first-stage reactor will enter the second-stage reactor and be formed at the entrance of the second-stage reactor.
  • the hydrogen effect deteriorates rapidly, and the acetylene content at the outlet of the reactor will soon rise to above 1 ppm.
  • the purity of ethylene is not good, which affects the progress of olefin polymerization, so the catalyst has to be regenerated.
  • Part of the device adopts an isothermal reactor.
  • the inside of the reactor extends the material flow direction and the temperature becomes lower and lower.
  • the green oil generated in the upper part of the reactor does not accumulate in the lower part of the reactor and gradually forms coking, which makes the selectivity drop quickly.
  • the carbon two fraction is hydrogenated in one stage, which has higher requirements for catalyst stability.
  • the selectivity of the catalyst will be significantly reduced due to the influence of green oil.
  • US5856262 reported a method for preparing low-acid palladium catalysts with potassium hydroxide (or hydroxides of barium, strontium, rubidium, etc.) modified silica as a carrier, at a space velocity of 3000h -1 , an inlet temperature of 35°C, and an inlet acetylene Under the conditions of 0.71% mole fraction and 1.43 hydrogen acetylene mole ratio, the outlet acetylene mole fraction is less than 1 ⁇ 10-7, and the ethylene selectivity reaches 56%.
  • potassium hydroxide or hydroxides of barium, strontium, rubidium, etc.
  • Patent CN200810114744.0 discloses an unsaturated hydrocarbon selective hydrogenation catalyst, preparation method and application method.
  • the catalyst uses alumina as a carrier and palladium as an active component.
  • the impurity resistance and coking resistance of the catalyst are improved by adding rare earth, alkaline earth metals and fluorine, but the selectivity of the catalyst is not ideal.
  • Patent CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst and its preparation method and application, including a carrier and main active components and auxiliary active components supported on the carrier, wherein the main active group Divided into Ni, the auxiliary active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn and Zr, the main active component and the auxiliary active component are both non- It exists in a crystalline form, the average particle size is less than 10 nm, the carrier is a porous material with no oxidizing properties; and the catalyst is prepared by a microemulsification method.
  • the catalysts prepared by the above methods all use catalysts with a single pore size distribution, and are affected by internal diffusion, and the selectivity of the catalyst is poor.
  • the carrier with bimodal pore distribution ensures the high activity of the catalyst, while the existence of macropores can reduce the influence of internal diffusion and improve the selectivity of the catalyst.
  • ZL971187339 discloses a hydrogenation catalyst.
  • the carrier is a honeycomb-type carrier with a large pore size, which effectively improves the selectivity of the catalyst.
  • CN1129606A discloses a hydrocarbon conversion catalyst and a preparation method.
  • the supported catalyst includes alumina, nickel oxide, iron oxide, etc.
  • the catalyst includes two kinds of pores, one is used to increase the catalytic reaction surface, and the other is beneficial to diffusion .
  • CN101433842A discloses a hydrogenation catalyst, wherein the catalyst has a bimodal pore distribution, the maximum radius of the small pore part is 2-50nm, and the maximum radius of the macropore part is 100-400nm. Because the catalyst has a bimodal pore distribution, it has With good hydrogenation activity, it also has good selectivity, and the ethylene increase is large.
  • 201310114070.5 discloses a method for selecting a carbon two fraction.
  • the hydrogenation method uses a catalyst, the active components of which are Pd and Ag are supported by an aqueous solution impregnation method, and Ni is supported by a W/O microemulsion impregnation method. After adopting this method, Pd/Ag and Ni are located in pore channels with different pore diameters, the green oil produced by the reaction is saturated and hydrogenated in the macropores, and the amount of coking of the catalyst is reduced.
  • the catalyst Before the catalyst is put into operation, the catalyst needs to be reduced. Generally, the reduction temperature of precious metal catalysts is relatively low, but the reduction temperature of Ni often reaches about 500°C. At this temperature, Pd atoms in the reduced state are very easy to accumulate, which reduces the catalyst activity by more than 30%. It is necessary to greatly increase the amount of active components. To compensate for the loss of activity, but it will cause a decrease in selectivity.
  • the purpose of the present invention is to provide a carbon two fraction hydrogenation method, especially a carbon two fraction alkyne selective hydrogenation method that can reduce catalyst coking.
  • the present invention provides a method for selective hydrogenation of C2 fraction alkyne, wherein the hydrogenation material is the C2 distillate from the top of the front deethanizer, which enters the fixed bed reactor and undergoes gas phase hydrogenation.
  • the process conditions of this selective hydrogenation reaction are: reactor inlet temperature 35-100°C, pressure 1.5-3.0MPa, gas volumetric space velocity 2000-11000h -1 ;
  • the catalyst used in the hydrogenation reaction is Al 2 O 3 is the carrier, with bimodal pore size distribution characteristics, the pore diameters are 15-50nm and 80-500nm respectively;
  • the fixed bed reactor described in the present invention is a fixed adiabatic bed or an isothermal bed reactor.
  • the idea of the hydrogenation method is to load the active component nickel/copper and a small amount of palladium in the macropores of the catalyst, and load the active component palladium in the small pores.
  • Acetylene and others mainly undergo selective hydrogenation reactions in small pores to produce ethylene.
  • the by-products of larger molecular size produced in the reaction are mainly carbon four to carbon sixteen fractions, which are more likely to enter the macropores, and the saturated hydrogenation reaction occurs under the action of active components such as nickel in the macropores. Because these molecules are saturated by hydrogenation, their molecular chains no longer grow, and they are easily carried out of the reactor by the materials.
  • the present invention found that if Ni and Cu are impregnated at the same time, the two will form an alloy. Due to the presence of Cu, the reduction temperature of Ni will be greatly reduced, reaching a minimum of 350°C, but this temperature is still too high for Pd catalysts .
  • the present invention also found that after a small amount of Pd is loaded on the Ni/Cu catalyst, the reduction temperature is greatly reduced, and can be reduced to 150°C. This temperature is completely acceptable for the Pd catalyst, because the general Pd catalyst has The reduction temperature is 100-150°C, and the catalyst can run for a longer time at 120-130°C in some cases, indicating that 100°C-150°C will not cause the aggregation of active components.
  • the conditions of the hydrogenation method of the present invention are:
  • the fixed-bed reactor is an adiabatic or isothermal reactor, and the reaction conditions are: reactor inlet temperature 35-100°C, reaction pressure 1.5-3.0Mpa, gas volumetric space velocity 2000-11000h -1 .
  • the hydrogenation feedstock is carbon distillate, in which 65-93% (v/v) of ethylene; 0.2-2.5% (v/v) of acetylene, preferably ethylene accounts for 65-93% (v/v). % (V/v), followed by ethane 5 to 35% (v/v), acetylene 0.3 to 2.5% (v/v), carbon three fraction 0.01 to 0.5% (v/v).
  • the above content is calculated based on the total volume of the hydrogenation feedstock as 100%.
  • the reactor inlet hydrogen/alyne is 1.3-2.2, preferably 1.3-1.8.
  • the hydrogen/alyne inlet of the one-stage reactor is 1.0-1.4
  • the hydrogen/acetylene inlet of the second-stage reactor is 1.5-2.5.
  • the hydrogen/alyne inlet of the first-stage reactor is 0.5-1.5
  • the hydrogen/alyne inlet of the second-stage reactor is 1.0-2.0
  • the three The hydrogen/alyne inlet of the stage reactor is 1.4-3.0
  • the hydrogen/alyne inlet of the first-stage reactor is 0.8-1.5
  • the hydrogen/alyne inlet of the second-stage reactor is 1.2-1.6
  • the hydrogen/alyne inlet of the three-stage reactor is 1.5-2.5.
  • the hydrogenation catalyst further contains 0.08-0.21% Ag, and Ag is supported by the solution; the preferred content of Pd is 0.035-0.075%; the part of Pd supported by the microemulsion is preferably The content is 1/110 to 1/200 of the Ni+Cu content. That is to say, the present invention also provides a method for selective hydrogenation of acetylenes from carbon two fractions, wherein the hydrogenation material is the carbon two fraction from the top of the front deethanizer tower, which enters the fixed bed reactor and undergoes gas phase hydrogenation to remove acetylene.
  • the process conditions of the selective hydrogenation reaction are: reactor inlet temperature 35-100°C, pressure 1.5-3.0MPa, gas volumetric space velocity 2000-11000h -1 ; the catalyst used in the hydrogenation reaction is Al 2 O 3
  • the carrier has the characteristics of bimodal pore size distribution, and the pore diameters are respectively 15-50nm and 80-500nm; the catalyst contains at least the active components Pd, Ag, Ni, Cu, based on 100% of the mass of the carrier, the catalyst contains 0.035 ⁇ 0.075% of Pd and 0.008 ⁇ 0.21% of Ag, Ag is supported by solution method, Ni, Cu and part of Pd are supported by microemulsion method, and the content of said part of Pd is 1/110 ⁇ of the content of Ni+Cu 1/200, the particle size of the microemulsion is 50-500nm.
  • the microemulsion loading refers to the traditional dipping loading
  • the dipping liquid is a microemulsion
  • the solution loading refers to the traditional dipping loading
  • the dipping liquid is a solution.
  • a part of Pd is supported in the form of microemulsion, and the rest of Pd is supported by impregnation, and the amount of Pd supported by the microemulsion is 1/100 to 1/200 of the content of Ni+Cu.
  • the particle size of the microemulsion is preferably not lower than the maximum pore diameter of the carrier and not higher than the maximum pore diameter of the macropore, for example, the particle diameter of the microemulsion is 50-500 nm.
  • the pore diameter of the small pores and the pore diameter of the macropores are respectively a size range, and the particle size of the microemulsion is not lower than the maximum pore diameter but not higher than the maximum pore diameter.
  • the maximum pore size of the pores means that the particle size of the microemulsion prepared during loading is not lower than the upper limit of the pore diameter range of a specific catalyst carrier and not higher than the upper limit of the macropore pore diameter range of the catalyst carrier.
  • the particle size of the microemulsion is greater than 50 nm and less than 500 nm.
  • the catalyst carrier used in this method is alumina with a bimodal pore size distribution structure, the small pore pore diameter of the carrier is 15-50 nm, and the macro pore pore diameter is 80-500 nm;
  • the active component of the catalyst used in the present invention includes Pd , Ni, Cu, and part of Pd are loaded by microemulsion, and its loading is carried out after the loading of Ni and Cu.
  • the particle size of the microemulsion is larger than the pore diameter of the small pores but smaller than the maximum pore diameter of the macropores. Due to the steric resistance, these components can only enter the macropores. Therefore, active centers with different hydrogenation effects are formed in the pores of the catalyst.
  • the macropores contain active centers composed of Ni/Cu and Pd, which have a good hydrogenation saturation effect on the green oil molecules, so that the green oil molecules entering the macropores will no longer polymerize, so they will gradually move out of the reactor. Formation of coking.
  • the catalyst used in the hydrogenation method of the present invention may also contain Ag.
  • Ag is supported by the aqueous solution method, and the content of Ag is 0.08-0.21%.
  • the role of Ag is to form an alloy with Pd to reduce the amount of green oil produced.
  • the catalyst needs to be reduced before hydrogenation, and the reduction temperature is 150-200°C.
  • the loading process of the catalyst in a microemulsion mode includes: dissolving the precursor salt in water, adding an oil phase, a surfactant and a co-surfactant, and fully stirring to form a microemulsion, wherein the oil phase is an alkane Or cycloalkane, the surfactant is an ionic surfactant and/or non-ionic surfactant, and the co-surfactant is an organic alcohol.
  • the weight ratio of the water phase/oil phase is 2.0-3.0; the weight ratio of the surfactant/co-surfactant is 1-1.2; the surface activity The weight ratio of agent/oil phase is 0.15 to 0.6.
  • the oil phase is preferably C 6 to C 8 saturated alkanes or cycloalkanes, more preferably cyclohexane and n-hexane;
  • the surfactant is preferably an ionic surfactant and/or non-ionic Type surfactants, more preferably nonionic surfactants: polyethylene glycol octyl phenyl ether or cetyl trimethyl ammonium bromide;
  • co-surfactants are preferably C 4 ⁇ C 6 alcohols, More preferably, it is n-butanol and/or n-pentanol.
  • the preferred catalyst preparation process includes the following steps:
  • step (1) and step (2) can be the same or different, preferably the same.
  • the Al 2 O 3 crystal form in the carrier in the above step (1) is preferably ⁇ , ⁇ or a mixed crystal form thereof.
  • the carrier in the above step (1) may be spherical, cylindrical, clover-shaped, four-leaf clover-shaped, and the like.
  • the ratio of the macropore volume to the small pore volume of the carrier in the above step (1) is not limited, and is determined according to the loading content of the active component.
  • the precursor salts of Ni, Cu, and Pd described in the above steps are soluble salts.
  • the mass ratio of Ni and Cu in the above step (1) is preferably 10:1 to 1:1.
  • the mass ratio of Ni+Cu to Pd supported by the emulsion method in steps (1) and (2) is 100:1 to 200:1.
  • a more preferred catalyst preparation process includes the following steps:
  • the microemulsion is loaded with Pd after Ni and Cu.
  • the solution loading Ag is after the solution loading Pd, and the loading of Pd and Ag can adopt the saturated spray method.
  • the order of the solution loading Pd and the microemulsion loading Ni and Cu is not limited.
  • This catalyst has the following characteristics: at the beginning of the hydrogenation reaction, due to the high hydrogenation activity of palladium and mainly distributed in the small pores, the selective hydrogenation reaction of acetylene mainly occurs in the small pores. With the extension of the catalyst running time, some by-products with larger molecular weight are formed on the surface of the catalyst. Because of the larger molecular size, more of these substances enter the macropores and the residence time is longer. Under the action of the nickel catalyst, Hydrogenation of the double bond occurs, and saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds are generated, and no larger molecular weight substances are generated.
  • the inventors also found that after using the catalyst, even if the reactant contains more heavy fractions, the amount of green oil produced by the catalyst is greatly increased, and the activity and selectivity of the catalyst still have no tendency to decrease.
  • the following characterization methods are used in the preparation process of the catalyst of the present invention: dynamic light scattering particle size analyzer to analyze the particle size distribution of Ni/Cu alloy microemulsion on M286572 dynamic light scattering analyzer; automatic mercury porosimeter, in the United States Analyze the pore volume, specific surface area and pore size distribution of the carrier on the 9510 Mercury Porosimeter of Mike Company. On the AA240FS atomic absorption spectrometer, the content of Pd, Ag, Ni, and Cu in the catalyst was measured.
  • Acetylene conversion rate [(reactor inlet acetylene content-reactor outlet acetylene content)/reactor outlet acetylene content]*100%
  • Ethylene selectivity ⁇ 2-[(reactor inlet hydrogen content-reactor outlet hydrogen content)/(reactor inlet acetylene content-reactor outlet acetylene content)])*100%
  • the initial conversion rate refers to the conversion rate of acetylene within 24 hours from the start of reactor feeding.
  • Coking amount [(catalyst weight after reaction-catalyst weight before reaction)/reactor catalyst weight]*100%
  • the particle size of the microemulsion prepared in step (1) was determined by dynamic light scattering as 50.29nm, and the particle size of the microemulsion prepared in step (3) was 51.45nm.
  • the element content was measured by atomic absorption spectrometry, and the catalyst prepared in Example 1 had a Pd content of 0.08%, a Ni content of 5.0%, and a Cu content of 0.5%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 150°C, holding for 8h.
  • the particle size of the microemulsion prepared in step (1) was determined to be 50.31 nm by the dynamic light scattering method, and the particle size of the microemulsion prepared in step (3) was 51.38 nm.
  • the element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 1A had a Pd content of 0.08% and a Ni content of 5.2%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 150°C, holding for 8h.
  • the particle size of the microemulsion prepared in step (1) was determined to be 50.31 nm by the dynamic light scattering method, and the particle size of the microemulsion prepared in step (3) was 51.49 nm.
  • the element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 1B had a Pd content of 0.08% and a Cu content of 0.52%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 150°C, holding for 8h.
  • the two-stage reactor process has a material space velocity of 4000/h, an operating pressure of 3.0 MPa, and a catalyst loading volume of 200 mL.
  • the reactor conditions are shown in Table 1.
  • the activity selectivity of the reaction in Comparative Examples 1A and 1B is the same as that of Example 1, but after 500 hours and 1000 hours, the activity selectivity of the reaction in Comparative Examples 1A and 1B is the same as
  • the gap in Example 1 gradually widened, because after the lack of Ni and Cu, the saturation hydrogenation activity for hydrogenation by-products was insufficient, resulting in serious coking of the catalyst.
  • the activity selectivity decreases.
  • the acetylene at the outlet of the reactor exceeds the required value, and the ethylene quality is unqualified.
  • step (1) Weigh 0.043 g of palladium nitrate, dissolve it in 80 g of water, add 26.67 g of cyclohexane, 4.0 g of Triton X-100, and 3.50 g of n-butanol, and stir well to form a microemulsion. After the semi-finished product A2 prepared in step (1) is immersed in the prepared microemulsion for 4 hours, the remaining liquid is filtered off, dried at 80°C, and calcined at 600°C for 4 hours to prepare the semi-finished product catalyst B2.
  • the particle size of the microemulsion prepared in step (1) is 487.63 nm
  • the particle size of the microemulsion prepared in step (2) is 486.19 nm.
  • the element content was determined by atomic absorption spectrometry, and the catalyst prepared in Example 2 was obtained, in which the Pd content was 0.065%, the Ni content was 1.1%, and the Cu content was 1.1%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 200°C, holding for 8h.
  • the particle size of the microemulsion prepared in step (1) is 487.65 nm, and the particle size of the microemulsion prepared in step (2) is 486.22 nm.
  • the element content was determined by atomic absorption spectrometry, and the catalyst prepared in Comparative Example 2 had a Pd content of 0.06%, a Ni content of 1.0%, and a Cu content of 1.1%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 200°C, holding for 8h.
  • the single-stage reactor process has a material space velocity of 4000/h, an operating pressure of 1.6 MPa, and a catalyst loading volume of 200 mL.
  • Reactor inlet materials acetylene 0.2% (v/v), ethylene 65% (v/v), C3 0.8% (v/v).
  • the reactor conditions are shown in Table 5.
  • Comparative Example 2 has a single pore size distribution without macropores, which causes the active components in the microemulsion to not enter the carrier or semi-finished product.
  • the pores of the catalyst are completely on the outer surface of the carrier and block the pores of the carrier, resulting in a decrease in the activity of the catalyst.
  • Table 6 shows the results of the single-stage reactor. Although the acetylene content at the reactor inlet is low, the high carbon three content also promotes the formation of more by-products in the hydrogenation reaction. Until 2000 hours, the acetylene content at the reactor outlet of the embodiment is always In the comparative example, because only a small amount of Ni-Cu was adsorbed on the outer surface of the catalyst, most of the by-products of hydrogenation could not be saturated hydrogenation, which caused the by-products to accumulate and coked, and the selectivity of the catalyst decreased and it could not be effectively removed. In addition to acetylene. After 1000 hours, the reaction result was already unqualified.
  • the particle size of the microemulsion prepared in step (2) is 78.38nm, and the particle size of the microemulsion prepared in step (3) is 77.64nm.
  • the element content was measured by atomic absorption spectroscopy, and it was obtained that in the catalyst prepared in Example 3, the Pd content was 0.035%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 150°C, holding for 4h.
  • the particle size of the microemulsion prepared in step (2) of the dynamic light scattering method is 78.45nm
  • the element content was determined by atomic absorption spectrometry, and it was obtained that in the catalyst prepared in Comparative Example 3A, the Pd content was 0.035%, the Ni content was 0.5%, the Cu content was 0.5%, and the Ag content was 0.08%.
  • Reduction of the catalyst reducing gas: hydrogen, reducing space velocity: 100h -1 , temperature 150°C, holding for 4h.
  • the first stage reactor inlet materials acetylene 0.5% (v/v), ethylene 70% (v/v), carbon three 0.8% (v/v).
  • Carrier A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 1078°C for 4 hours, the bimodal pore size distribution ranges from 20 to 35 nm and 90 to 250 nm, the water absorption rate is 57%, and the specific surface area is 44.82 m 2 /g. Weigh 100 g of the carrier.
  • the particle size of the microemulsion emulsion prepared in step (1) of the dynamic light scattering measurement is 51.19 nm, and the particle size of the microemulsion emulsion prepared in step (4) is 50.85 nm.
  • the prepared catalyst was determined by atomic absorption spectrometry.
  • the Pd content was 0.05%
  • the Ni content was 1%
  • the Cu content was 0.25%
  • the Ag content was 0.14%.
  • Carrier A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 1078°C for 4 hours, the bimodal pore size distribution ranges from 20 to 35 nm and 90 to 250 nm, the water absorption rate is 62%, and the specific surface area is 44.82 m 2 /g. Weigh 100 g of the carrier.
  • the particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (1) is 52.18 nm.
  • the particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (4) is 26.58 nm.
  • the element content of the prepared catalyst was determined by atomic absorption spectrometry.
  • the Pd content was 0.05%
  • the Ni content was 1%
  • the Cu content was 0.25%
  • the Ag content was 0.15%.
  • Carrier A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3mm is used. After calcination at 1078°C for 4 hours, the bimodal pore size distribution ranges from 20 to 35 nm and 90 to 250 nm, the water absorption rate is 57%, and the specific surface area is 44.82 m 2 /g. Weigh 100 g of the carrier.
  • the particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (1) is 52.13 nm.
  • the particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (4) is 595.09 nm.
  • the prepared catalyst element content was determined by atomic absorption spectrometry.
  • the Pd content was 0.05%
  • the Ni content was 1.0%
  • the Cu content was 0.25%
  • the Ag content was 0.15%.
  • the two-stage reactor process the material space velocity is 5000/h, the operating pressure is 2.2MPa, and the catalyst loading capacity is 200mL.
  • the reactor conditions are shown in Table 9.
  • Material composition The inlet material of the first stage reactor: acetylene 1.4% (v/v), ethylene 85% (v/v), carbon three 0.5% (v/v).
  • the first and second stages are adiabatic reactors, the material space velocity is 5000/h, the third stage is an isothermal reactor, the material space velocity is 11000/h, the operating pressure is 2.5MPa, and the catalyst loading of the first and second stages is 1000mL .
  • the reactor conditions are shown in Table 11.
  • Carrier A commercially available spherical alumina-magnesia carrier with bimodal pore distribution is used, the magnesium oxide content is 3%, and the diameter is 3mm. After calcination at 1065°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 58%, and the specific surface area is 42.38 m 2 /g. Weigh 100 g of the carrier.
  • the particle size of the microemulsion emulsion in step (1) of the dynamic light scattering measurement preparation is 65.0 nm, and the particle size of the microemulsion emulsion in step (4) is 65.24 nm.
  • the prepared catalyst element content was measured by atomic absorption spectrometry.
  • the Pd content was 0.04%
  • the Ni content was 0.75%
  • the Cu content was 0.75%
  • the Ag content was 0.21%.
  • the catalyst preparation conditions are the same as in Example 5, except that the preparation step does not support Pd in the emulsion method.
  • Carrier A commercially available spherical alumina-magnesia carrier with bimodal pore distribution is used, the magnesium oxide content is 3%, and the diameter is 3mm. After calcination at 1000°C for 4 hours, the bimodal pore size distribution ranges from 23 to 47 nm and 80 to 380 nm, the water absorption rate is 58%, and the specific surface area is 40 m 2 /g. Weigh 100 g of the carrier.
  • step (3) Weigh 1.648g of nickel chloride and 2.175g of copper nitrate, dissolve in 80mL of deionized water, add 36.00g of n-hexane, add 20.88g of Triton X-100, add 19.4g of n-hexanol, stir well to form a microemulsion,
  • the semi-finished catalyst B5-1 prepared in step (2) was immersed in the prepared microemulsion, shaken for 180 minutes, filtered off the remaining liquid, dried at 70°C, and calcined at 500°C for 4 hours to obtain the desired catalyst.
  • the particle size of the microemulsion emulsion prepared in the dynamic light scattering measurement step (4) is 65.20 nm.
  • the prepared catalyst was determined by atomic absorption spectrometry.
  • the Pd content was 0.04%
  • the Ni content was 0.75%
  • the Cu content was 0.75%
  • the Ag content was 0.21%.
  • each stage is an adiabatic reactor, the material space velocity is 11000/h, the operating pressure is 2.3MPa, and the catalyst loading is 1000mL.
  • the reactor conditions are shown in Table 13.
  • Material composition One-stage reactor inlet acetylene: 1.5% (v/v), ethylene 70% (v/v).

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Abstract

一种碳二馏分炔烃选择加氢方法，其加氢物料为来自前脱乙烷塔塔顶的碳二馏分，进入固定床反应器后进行气相加氢脱除乙炔，该选择性加氢反应的工艺条件为：反应器入口温度35～100℃，压力1.5～3.0MPa，气体体积空速2000～11000h -1；加氢反应所使用的催化剂以Al 2O 3为载体，具有双峰孔径分布特征，孔径分别在15～50nm及80～500nm；所述的催化剂至少含有活性组分Pd、Ni、Cu，以载体的质量100％计，所述的催化剂含0.03～0.09％的Pd，0.5～5％的Ni，Cu：Ni＝0.1～1:1，Ni、Cu及部分的Pd采用微乳液负载，所述的部分Pd的含量是所述的Ni+Cu含量的1/100～1/200，所述的微乳液的粒径在50～500nm。该加氢方法具有乙炔脱除效果好，选择性高及运行稳定性好的特点。

Description

一种碳二馏分炔烃选择加氢方法 技术领域
本发明涉及一种碳二馏分选择加氢方法，特别是涉及一种保持加氢反应选择性稳定的碳二馏分选择加氢方法。
背景技术
乙烯是石油化学工业最重要的基础原料之一，作为合成各种聚合物的单体乙烯，绝大部分由石油烃(如乙烷、丙烷、丁烷、石脑油和轻柴油等)蒸汽裂解制得。经这种方法得到的以乙烯为主的C 2馏分中含有0.5％～2.3％(摩尔分数)的乙炔。乙烯中如果有较多乙炔存在会使乙烯的聚合过程复杂化，恶化聚合物性能。降低聚合催化剂活性，增加催化剂的消耗。所以必须将乙烯中的乙炔含量降到一定值以下，才能作为合成高聚物的单体。
目前工业上普遍采用选择加氢的方法脱除乙烯中的乙炔，采用的催化剂主要为Pd，Pt，Au等为活性组分的贵金属催化剂。为了保证乙炔加氢生成的乙烯和原料中原有的乙烯不继续加氢生成乙烷，造成乙烯损失，必须保证催化剂的较高的加氢选择性，才能提高装置的经济效益。
因此，碳二加氢是石油化工业中极其重要的一个工序，它直接影响整个乙烯装置运行的稳定性。
碳二加氢工艺按加氢物料及条件，主要分为两种工艺，由于反应器所在的位置决定了反应物料的组成，所以通俗地按照反应器与其它部件的相对位置来命名，如同前加氢和后加氢是指乙炔加氢反应器相对于脱甲烷塔位置而言，加氢反应器位于脱甲烷塔之前为前加氢，加氢反应器位于脱甲烷塔之后为后加氢。
碳二后加氢工艺一般采用三段加氢反应器，一段反应器的乙炔总转化率在50～80％，氢/炔1.0～1.4，二段反应器的乙炔总转化率40～20％，氢/炔1.4～2.0，残余的乙炔在三段反应器完全转化，三段氢/炔2.5～4.0，三段反应器出口的乙炔含量一般在1ppm以下。碳二后加氢反应中，会发生乙炔的加氢二聚，生成一系列分子量不同的低聚物，这些低聚物由于不能随气相物料流动或移动速率很低，会较长时间附着在催化剂表面或进入孔到内，造成催化剂孔堵塞。由于移动速率慢，会逐步集聚，这些低聚物本身有含有大量不饱和键，还可以进一步聚合，最终形成结焦，使催化剂活性选择性大幅度下降。
加氢二聚产物的量与加氢条件密切相关，在低氢/炔时，由于氢气不足，乙炔的加氢二聚反应十分剧烈；催化剂结焦速率会十分迅速。
在反应过程中，由于一段反应器的除炔负荷大，一段反应器生成绿油的量也是最大的，一段反应器入口处的加氢二聚反应最剧烈，部分绿油在一段反应器入口聚合，使这部分催化剂活性迅速下降。另一个部位是一段反应器的出口，这是因为随加氢反应进行，氢/炔愈来愈低，使加氢二聚反应速率再上升，而且温度的升高又会使绿油的聚合加剧。
部分碳二后加氢装置采用了两段加氢工艺，一段反应器生成的绿油，部分会进入二段反应器，而且在二段反应器入口处聚集而形成，使二段反应器的加氢效果迅速恶化，反应器出口乙炔含量很快会上升到在1ppm以上，乙烯的纯度不好，影响烯烃聚合的进行，因此不得不对催化剂进行再生。
部分装置采用等温反应器，该反应器内延物料流动方向，温度愈来愈低，反应器上部生成的绿油在反应器下部不聚集，并逐渐形成结焦，使选择性下降很快。
部分乙烯装置，碳二馏分采用一段加氢，对催化剂稳定性的要求更高，一般催化剂在运行3个月后，由于绿油的影响，催化剂选择性会明显下降。
有些装置为了调节各反应器的加氢负荷，有时会人为地降低配入的氢气量，使某反应器入口氢/炔甚至低于1，会大大加速催化剂结焦，虽然调节了各反应器的负荷，却导致催化剂运行周期明显缩短。
结焦量一旦达到碳二加氢催化剂自身质量的10％以上，性能下降就很明显，绿油的生成如此严重的影响碳二后加氢催化剂的性能，但加氢二聚又不可避免，因此，使得如何降低绿油生成和延缓结焦成为催化剂设计中的永恒的课题之一。
US5856262报道了以氢氧化钾(或钡、锶、铷等的氢氧化物)改性的氧化硅为载体，制备低酸性钯催化剂的方法，在空速3000h -1，入口温度35℃，入口乙炔摩尔分数0.71％，氢炔摩尔比1.43的条件下，出口乙炔摩尔分数小于1×10-7，乙烯选择性达56％。
专利CN200810114744.0公开了一种不饱和烃选择加氢催化剂，制备方法及应用方法。该催化剂以氧化铝为载体，以钯为活性组分，通过加入稀土和碱土金属和氟提高催化剂抗杂质和抗结焦性能，但催化剂选择性并不理想。
专利CN200810119385.8公开了一种非贵金属负载型选择加氢催化剂及其制备方法和应用，包括载体以及负载在该载体上的主活性组分和助活性组分，其中，所述的主活性组分为Ni，所述的助活性组分选自Mo、La、Ag、Bi、Cu、Nd、Cs、Ce、Zn和Zr中的至少一种，主活性组分和助活性组分均以非晶态形式存在，平均粒径＜10nm，所述载体为不具氧化性的多孔材料；且所述的催化剂以微乳化法制备。
以上方法制备的催化剂均采用孔径单一分布的催化剂，受到内扩散的影响，催化剂 的选择性较差。具有双峰孔分布的载体，在保证催化剂高活性的同时，大孔的存在可以减少内扩散的影响，提高催化剂选择性。
ZL971187339公开了一种加氢催化剂，载体是一种蜂窝型载体，为大孔径载体，有效的提高了催化剂的选择性。
CN1129606A公开了一种烃类转化催化剂及制备方法，其载体催化剂包括氧化铝、氧化镍、氧化铁等，该催化剂中包括两种孔，一种用于提高催化反应表面，另一种有利于扩散。CN101433842A公开了一种加氢催化剂，其中催化剂具有双峰孔分布，小孔部分最可几半径为2～50nm，大孔部分最可几半径为100～400nm，由于催化剂为双峰孔分布，具有良好的加氢活性的同时，又有好的选择性，乙烯增量大。
201310114070.5公开了一种碳二馏分选择的方法，该加氢方法中采用了一种催化剂，其活性组分Pd，Ag采用水溶液浸渍法负载，Ni是采用W/O微乳液浸渍法负载的。采用该方法后，Pd/Ag与Ni位于不同孔径的孔道中，反应生成的绿油在大孔中饱和加氢，催化剂结焦量降低。
在催化剂投运前，需要对催化剂进行还原。一般贵金属催化剂还原温度较低，但Ni的还原温度往往要达到500℃左右，在该温度下还原态的Pd原子极易聚集，使催化剂活性降低30％以上，需要大幅度增加活性组分等量以补偿活性损失，但又会引起选择性的下降。
发明内容
本发明的目的在于提供一种碳二馏分加氢方法，尤其是一种可以降低催化剂结焦的碳二馏分炔烃选择加氢方法。
为达到上述目的，本发明提供了一种碳二馏分炔烃选择加氢方法，其中，加氢物料为来自前脱乙烷塔塔顶的碳二馏分，进入固定床反应器后进行气相加氢脱除乙炔，该选择性加氢反应的工艺条件为：反应器入口温度35～100℃，压力1.5～3.0MPa，气体体积空速2000～11000h -1；加氢反应所使用的催化剂以Al 2O 3为载体，具有双峰孔径分布特征，孔径分别在15～50nm及80～500nm；所述的催化剂至少含有活性组分Pd、Ni、Cu，以载体的质量100％计，所述的催化剂含0.03～0.09％的Pd，0.5～5％的Ni，Cu：Ni＝0.1～1:1，Ni、Cu及部分Pd的负载采用微乳液负载，所述的部分Pd的含量是所述的Ni+Cu含量的1/100～1/200，所述的微乳液的粒径在50～500nm。
本发明中所述的固定床反应器是固定绝热床或等温床反应器。
该加氢方法的思路是：在催化剂大孔中负载活性组分镍/铜及少量钯，在小孔中负载 活性组分钯。乙炔等主要在小孔中发生选择性加氢反应，生成乙烯。而反应中生成的较大分子尺寸的副产物，主要为碳四至碳十六馏分，更容易进入大孔中，在大孔中的镍等活性组分的作用下发生饱和加氢反应。由于这些分子被加氢饱和，其分子链不再增长，因而容易被物料带出反应器。
本发明发现如果将Ni和Cu同时浸渍，二者会形成合金，由于Cu的存在，Ni的还原温度会有较大幅度的降低，最低达到350℃，但这个温度对Pd催化剂来讲仍然太高。
本发明还发现，将少量在Pd负载在Ni/Cu催化剂上后，其还原温度有大幅度降低，可以降低到150℃，这个温度对Pd催化剂来讲是完全可以接受的，因为一般Pd催化剂的还原温度是100～150℃，催化剂在有些情况下在120-130℃可以较长时间运行，说明100℃～150℃不会引起活性组分的聚集。
本发明加氢方法的条件是：
固定床反应器为绝热或等温反应器，反应条件为：反应器入口温度35～100℃，反应压力1.5～3.0Mpa，气体体积空速2000～11000h -1。
本发明所述的加氢方法中，加氢原料为碳二馏分，其中乙烯65～93％(v/v)；乙炔0.2～2.5％(v/v)，优选的是，乙烯占65～93％(v/v)，其次为乙烷5～35％(v/v)，乙炔0.3～2.5％(v/v)，碳三馏分0.01～0.5％(v/v)。上述含量以加氢原料的总体积为100％计算。
本发明所述的加氢方法，优选地：使用固定床反应器单段反应器加氢时，反应器入口氢/炔1.3～2.2，优选1.3-1.8。
本发明所述的加氢方法，优选地：使用固定床反应器两段反应器加氢时，一段反应器入口氢/炔1.0～1.4，二段反应器入口氢/炔1.5～2.5。
本发明所述的加氢方法，优选地：使用固定床反应器三段反应器串联加氢时，一段反应器入口氢/炔0.5～1.5，二段反应器入口氢/炔1.0～2.0，三段反应器入口氢/炔1.4～3.0，优选的是，一段反应器入口氢/炔0.8～1.5，二段反应器入口氢/炔1.2～1.6，三段反应器入口氢/炔1.5～2.5。
本发明所述的加氢方法，优选地，所述的加氢催化剂还含有0.08～0.21％的Ag，Ag通过溶液负载；Pd的优选含量为0.035～0.075％；微乳液负载的部分Pd优选的含量是所述的Ni+Cu含量的1/110～1/200。即本发明还提供了一种碳二馏分炔烃选择加氢方法，其中：加氢物料为来自前脱乙烷塔塔顶的碳二馏分，进入固定床反应器后进行气相加氢脱除乙炔，该选择性加氢反应的工艺条件为：反应器入口温度35～100℃，压力1.5～3.0MPa，气体体积空速2000～11000h -1；加氢反应所使用的催化剂以Al 2O 3为载体，具 有双峰孔径分布特征，孔径分别在15～50nm及80～500nm；所述的催化剂至少含有活性组分Pd、Ag、Ni、Cu，以载体的质量100％计，所述的催化剂含0.035～0.075％的Pd及0.008～0.21％的Ag，Ag是采用溶液法负载，Ni、Cu及部分的Pd采用微乳液法负载，所述部分Pd的含量是Ni+Cu含量的1/110～1/200，所述微乳液的粒径在50～500nm。
本发明中，微乳液负载是指传统的浸渍负载，其浸渍液为微乳液，溶液负载是指传统的浸渍负载，其浸渍液为溶液。
在本发明的催化剂中，一部分Pd以微乳液的形式负载，而其余的Pd以浸渍的方式负载，并且，微乳液负载的Pd的量是Ni+Cu含量的1/100～1/200。
根据本发明的具体实施方案，微乳液的粒径优选不低于载体的小孔的最大孔径而不高于大孔的最大孔径，例如微乳液的粒径50～500nm。对于一个具体的具有双峰孔径分布的催化剂载体来说，其小孔的孔径、大孔的孔径分别是一个尺寸范围，而微乳液的粒径不低于小孔的最大孔径而不高于大孔的最大孔径是指负载时所配制的微乳液的粒径不低于某个具体的催化剂载体的小孔的孔径范围的上限、不高于催化剂载体的大孔的孔径范围的上限。优选地，微乳液的粒径大于50nm、小于500nm。
本方法所采用的催化剂载体为具有双峰孔径分布结构氧化铝，所述的载体的小孔孔径为15～50nm，大孔孔径为80～500nm；本发明所采用的催化剂的活性组分包括Pd，Ni，Cu，部分的Pd采用微乳液负载，它的负载是在Ni，Cu的负载之后进行。
所述的微乳液粒径大于小孔的孔径而小于大孔的最大孔径。由于空间阻力的原因，这些组分只能进入大孔，因此在催化剂的大小孔中，形成了具有不同加氢作用的活性中心。大孔中含有由Ni/Cu及Pd组成的活性中心，它对绿油分子有很好的加氢饱和作用，使进入大孔中的绿油分子不再聚合，因此会逐渐移出反应器，不易形成结焦。
本发明的加氢方法所用的催化剂还可以含有Ag，Ag采用水溶液法负载，Ag的含量0.08～0.21％。Ag的作用是和Pd形成合金，减少绿油的生成量。
本发明中，优选地，所述催化剂在加氢前，需要进行还原，还原温度为150～200℃。
本发明中，优选地，所述催化剂的微乳液方式负载过程包括：将前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液，其中油相为烷烃或环烷烃，表面活性剂为离子型表面活性剂和/或非离子型表面活性剂，助表面活性剂为有机醇。
本发明中，优选地，微乳液制备中，水相/油相的重量比为是2.0～3.0；所述的表面活性剂/助表面活性剂的重量比是1～1.2；所述的表面活性剂/油相的重量比为0.15～0.6。
本发明中，微乳液制备中，油相优选是C 6～C 8饱和烷烃或环烷烃，更优选的是环 己烷、正己烷；表面活性剂优选为离子型表面活性剂和/或非离子型表面活性剂，更优选为非离子型表面活性剂：聚乙二醇辛基苯基醚或十六烷基三甲基溴化铵；助表面活性剂优选为C 4～C 6醇类，更优选为正丁醇和/或正戊醇。
本发明中，优选的催化剂制备过程，包含以下步骤：
(1)将Ni和Cu的前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液；制备微乳液的条件是：表面活性剂/助表面活性剂的重量比为1～1.2，水相/油相的重量比为2.0～3.0，表面活性剂/油相的重量比为0.15～0.6；将载体加入到制好的微乳液中浸渍0.5～4小时后，滤除余液；在40～80℃下干燥，在400～600℃下焙烧，得到半成品催化剂A；
(2)将Pd前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液；制备微乳液的条件是：表面活性剂和助表面活性剂的重量比为1～1.2，水相和油相的重量比为2.0～3.0，表面活性剂和油相的重量比为0.15～0.6；将半成品催化剂A加入到制好的微乳液中浸渍0.5～4小时后，滤除余液；干燥后，在400～600℃下焙烧，得到半成品催化剂B；
(3)将Pd的前驱体盐溶于水，调pH为1.5～2.5，再将半成品催化剂B加入Pd的盐溶液中，浸渍吸附0.5～4h后，干燥后在400～600℃条件下焙烧，得到成品催化剂。
对一个样品来说，步骤(1)和步骤(2)的条件可以相同，也可以不同，最好是相同。
上述步骤(1)中的载体中Al 2O 3晶型最好为θ、α或其混合晶型。
上述步骤(1)中的载体可以是球形、圆柱形、三叶草形、四叶草形等。
上述步骤(1)中的载体其大孔孔体积和小孔孔体积比不限，根据活性组分负载含量决定。
上述步骤中所述的Ni，Cu，Pd的前驱体盐为可溶性盐。
上述步骤(1)中所述的Ni和Cu的质量比最好为10:1～1:1。
步骤(1)、(2)中Ni+Cu与乳液法负载的Pd的质量比为100:1～200:1。
本发明中，更优选的催化剂制备过程包含以下步骤：
(1)将Ni及Cu的前驱体盐溶于水中，加入计量的油相、表面活性剂及助表面活性剂，充分搅拌形成微乳液，控制微乳液粒径大于50nm、小于500nm，将载体加入到制好的微乳液中浸渍0.5～4小时后，滤除余液，用去离子水洗至中性，干燥焙烧得到半成品催化剂A；
(2)将Pd的前驱体盐溶于去离子水，加入计量的油相、表面活性剂及助表面活性剂，充分搅拌形成微乳液，充分搅拌形成微乳液，控制微乳液粒径大于50nm、小于500nm；将半成品A加入到制好的微乳液中浸渍0.5～4小时后，滤除余液，用去离子水洗至中性，干燥焙烧得到半成品催化剂B；
(3)将Pd的前驱体盐溶于去离子水，再将半成品催化剂B加入Pd的盐溶液中，浸渍10-120分钟后，干燥，焙烧得到半成品催化剂C；
(4)将Ag的前驱体盐溶于水，得到的水溶液的量与半成品催化剂C饱和吸水量相当，再将半成品C加入Ag的盐溶液中，待溶液完全吸收后，干燥、焙烧得到所要的催化剂。
上述的制备步骤中，微乳液负载Pd是在Ni、Cu之后。
上述的制备步骤中，溶液负载Ag是在溶液负载Pd之后，Pd，Ag的负载可采用饱和喷淋法。
上述的制备步骤中，溶液负载Pd与微乳液负载Ni、Cu的次序不限定。
此催化剂具有以下特性：在加氢反应开始时，由于钯的加氢活性高，而且主要分布在小孔中，因而乙炔的选择性加氢反应主要发生在小孔中。随着催化剂运行时间的延长，催化剂表面生成了一部分分子量较大的副产物，这些物质由于分子尺寸较大，较多的进入大孔中，而且停留时间较长，会在镍催化剂的作用下，发生双键的加氢反应，而生成饱和烃或不含孤立双键的芳香烃，不再生成分子量更大的物质。
本发明人还发现，使用该催化剂后，即使反应物中含较多重馏分，催化剂绿油生成量大幅增加，催化剂活性及选择性仍没有下降的趋势。
具体实施方式
本发明的催化剂在制备过程中用到以下表征方法：动态光散射粒径分析仪，在M286572动态光散射分析仪上分析Ni/Cu合金的微乳液粒径分布；全自动压汞仪，在美国麦克公司9510型压汞仪上分析载体的孔体积、比表面积和孔径分布。在AA240FS原子吸收光谱仪上，测定催化剂中Pd、Ag、Ni、Cu的含量。
乙炔转化率＝[(反应器入口乙炔含量-反应器出口乙炔含量)/反应器出口乙炔含量]*100％
乙烯选择性＝{2-【(反应器入口氢气含量-反应器出口氢气含量)/(反应器入口乙炔含量-反应器出口乙炔含量)】}*100％
初始转化率是指反应器投料开始，24小时内的乙炔转化率。
结焦量＝[(反应后催化剂重量-反应前催化剂重量)/反应器催化剂重量]*100％
实施例1：
催化剂制备：
市售双峰孔分布球形氧化铝载体，直径为4mm。经过1058℃焙烧4h后，孔径分布范围分别是15～32nm和80～204nm，吸水率60％，比表面积为47.28m 2/g，称取该载体100g。
(1)称取无水硝酸镍15.94g，硝酸铜1.47g溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液。将载体加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h。得到半成品催化剂A。
(2)称取0.079g氯化钯溶于120mL去离子水中，调pH为1.5，再将半成品催化剂A加入Pd的盐溶液中，浸渍吸附30min后，100℃干燥，400℃条件下焙烧6h，得到半成品催化剂B。
(3)称取硝酸钯0.071g溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液，将半成品催化剂B加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h，即制得所要的催化剂。
动态光散射法测定步骤(1)制备的微乳液的粒径为50.29nm，步骤(3)制备的微乳液的粒径为51.45nm。
用原子吸收光谱法测定元素含量，得到实施例1所制备的催化剂中，Pd的含量为0.08％，Ni含量为5.0％，Cu含量为0.5％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度150℃，保持8h。
对比例1A：
市售双峰孔分布球形氧化铝载体，直径为4mm。经过1058℃焙烧4h后，孔径分布范围分别是15～32nm和80～204nm，吸水率60％，比表面积为47.28m 2/g，称取该载体100g。
(1)称取无水硝酸镍15.94g，溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液。将载体加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h。得到半成品催化剂A1-1。
(2)称取0.079g氯化钯溶于120mL去离子水中，调pH为1.5，再将半成品催化剂A1-1加入Pd的盐溶液中，浸渍吸附30min后，100℃干燥，400℃条件下焙烧6h，得到半成品催化剂B1-1。
(3)称取硝酸钯0.071g溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液，将半成品催化剂B1-1加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h，即制得所要的催化剂。
动态光散射法测定步骤(1)制备的微乳液的粒径为50.31nm，步骤(3)制备的微乳液的粒径为51.38nm。
用原子吸收光谱法测定元素含量，得到对比例1A所制备的催化剂中，Pd的含量为0.08％，Ni含量为5.2％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度150℃，保持8h。
对比例1B
市售双峰孔分布球形氧化铝载体，直径为4mm。经过1058℃焙烧4h后，孔径分布范围分别是15～32nm和80～204nm，吸水率60％，比表面积为47.28m 2/g，称取该载体100g。
(1)称取硝酸铜1.47g溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液。将载体加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h，得到半成品催化剂A1-2。
(2)称取0.079g氯化钯溶于120mL去离子水中，调pH为1.5，再将半成品催化剂A1-2加入Pd的盐溶液中，浸渍吸附30min后，100℃干燥，400℃条件下焙烧6h，得到半成品催化剂B1-2。
(3)称取硝酸钯0.071g溶于72mL去离子水中，加正己烷36g，加CATB21.6g，加正戊醇21.50g，充分搅拌形成微乳液，将半成品催化剂B1-2加入到制好的微乳液中浸渍30min后，滤除余液，在40℃下干燥，在400℃下焙烧6h，即制得所要的催化剂。
动态光散射法测定步骤(1)制备的微乳液的粒径为50.31nm，步骤(3)制备的微乳液的粒径为51.49nm。
用原子吸收光谱法测定元素含量，得到对比例1B所制备的催化剂中，Pd的含量为0.08％，Cu含量为0.52％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度150℃，保持8h。
实施效果
加氢反应条件
二段反应器工艺，物料空速4000/h，操作压力3.0MPa，催化剂装填量200mL。反应器条件如表1所示。
物料组成：一段反应器入口乙炔：1.8％(v/v)，乙烯80％(v/v)。
表1各段反应器条件
Figure PCTCN2020121914-appb-000001
表2反应结果
Figure PCTCN2020121914-appb-000002
从表2的评价结果看，在24小时内，对比例1A和1B中反应的活性选择性与实施例1相同，但500小时和1000小时后，对比例1A和1B中反应的活性选择性与实施例1差距逐渐拉大，原因是Ni和Cu缺失后，对加氢副产物饱和加氢活性不足，导致催化剂结焦严重。活性选择性下降。反应器出口乙炔超过要求值，乙烯质量不合格。
实施例2
催化剂制备：
称取市售双峰孔分布球形氧化铝载体，直径为4mm。经过1115℃焙烧4h后，孔径分布范围分别是30～43nm和112～496nm，吸水率为50％，比表面积为21.74m 2/g，称取该载体100g。
(1)称取无水硝酸镍3.19g，硝酸铜2.95g溶于80g水中，加入26.67g环己烷，4.0g  TritonX-100，3.50g正丁醇充分搅拌形成微乳液。将载体加入到制好的微乳液中浸渍4小时后，滤除余液，在80℃下干燥，在600℃下焙烧4h得到所需的半成品催化剂A2。
(2)称取硝酸钯0.043g，溶于80g水中，加入26.67g环己烷，4.0g TritonX-100，3.50g正丁醇，充分搅拌形成微乳液。将步骤(1)制备的半成品A2浸渍到制备的微乳液中浸渍4小时后，滤除余液，在80℃下干燥，在600℃焙烧4h，制得半成品催化B2。
(3)称取0.067g氯化钯盐溶于120mL去离子水中，调pH为2.5，再将半成品催化剂B2加入Pd的盐溶液中，浸渍吸附1小时后，120℃干燥，600℃条件下焙烧4h，得到成品催化剂。
用动态光散射法(激光光散射法)测定，步骤(1)制备的微乳液的粒径为487.63nm，步骤(2)制备的微乳液的粒径为486.19nm。
用原子吸收光谱法测定元素含量，得到实施例2所制备的催化剂中，其中Pd含量为0.065％，Ni含量为1.1％，Cu含量为1.1％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度200℃，保持8h。
对比例2
催化剂制备：
称取市售球形单峰孔氧化铝载体，直径为4mm。经过1115℃焙烧4h后，孔径分布范围是32～88nm，吸水率为50％，比表面积为21.74m 2/g，称取该载体100g。
(1)称取无水硝酸镍3.19g，硝酸铜2.95g溶于80g水中，加入26.67g环己烷，4.0g TritonX-100，3.50g正丁醇充分搅拌形成微乳液。将制备的载体加入到制好的微乳液中浸渍4小时后，滤除余液，在80℃干燥，在600℃焙烧4h得到所需的半成品催化剂A2-1。
(2)称取硝酸钯0.043g，溶于80g水中，加入26.67g环己烷，4.0g TritonX-100，3.50g正丁醇，充分搅拌形成微乳液。将步骤(1)制备的半成品A2-1浸渍到制备的微乳液中浸渍4小时后，滤除余液，用去离子水洗涤至中性。在80℃下干燥，在600℃下焙烧4h，制得半成品催化剂B2-1。
(3)。称取0.067g氯化钯盐溶于120mL去离子水中，调pH为2.5，再将半成品催化剂B2-1加入Pd的盐溶液中，浸渍吸附1小时后，120℃干燥，600℃条件下焙烧4h，得到成品催化剂。
动态光散射法测定步骤(1)制备的微乳液的粒径为487.65nm，步骤(2)制备的微乳液的粒径为486.22nm。
用原子吸收光谱法测定元素含量，得到对比例2所制备的催化剂中，Pd含量为 0.06％，Ni含量为1.0％，Cu含量为1.1％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度200℃，保持8h。
实施效果
加氢反应条件1
三段反应器工艺，物料空速11000/h，操作压力1.5MPa，催化剂装填量300mL。反应器条件如表3所示。
物料组成：一段反应器入口乙炔：2.5％(v/v)，乙烯93％(v/v)。
表3各段反应器条件
Figure PCTCN2020121914-appb-000003
表4反应结果
Figure PCTCN2020121914-appb-000004
加氢反应条件2
单段反应器工艺，物料空速4000/h，操作压力1.6MPa，催化剂装填量200mL。
反应器入口物料：乙炔0.2％(v/v)，乙烯65％(v/v)，C3 0.8％(v/v)。反应器条件如表5所示。
表5反应器条件
  500小时前 500-1000小时 1000-2000小时
氢/炔 1.5 1.8 2.0
入口温度 40 55 65
表6反应结果
Figure PCTCN2020121914-appb-000005
从表4的结果看，反应初期对比例2与实施例2已经有区别，原因是对比例2中的载体为单孔径分布，没有大孔，导致微乳液中的活性组分不能进入载体或半成品催化剂的孔中，完全在载体的外表面，并堵塞载体的孔道，导致催化剂活性的下降。
随反应进行，生成的副产物在催化剂壳层内累积，并形成结焦，对比例2中的催化剂性能逐渐下降。位于催化剂表面的活性组分虽然有一定的对副产物饱和加氢的功能，但只能使部分加氢副产物饱和加氢，孔的堵塞现象愈来愈严重，催化剂性能下降明显。
表6为单段反应器结果，虽然反应器入口乙炔含量较低，但碳三含量很高也促使加氢反应中形成较多的副产物，直至2000小时，实施例的反应器出口乙炔含量始终为0，而对比例中，由于仅少量Ni-Cu吸附在催化剂外表面，不能对大部分地加氢副产物进行饱和加氢，致使副产物不断累积而结焦，催化剂选择性下降而不能有效脱除乙炔。1000小时后反应结果已经不合格。
实施例3
催化剂制备：
称取市售双峰孔分布球形氧化铝载体，直径为4mm。经过1092℃焙烧4h后，孔径分布范围分别是20～46nm和85～350nm，吸水率为58％，比表面积为39.58m 2/g，称取该载体100g。
(1)称取0.051g氯化钯盐溶于140mL去离子水中，调pH为2，再将载体加入Pd的盐溶液中，浸渍吸附50min后，110℃干燥，550℃条件下焙烧5h，得到所需的半成品催化剂A3。
(2)称取无水硝酸镍1.59g，硝酸铜1.47g，溶于71.5g水中，加入28.80g正己烷，17.16g CTAB，15.6g正戊醇充分搅拌形成微乳液，将半成品催化剂A3加入到制好的微乳液中浸渍80min后，滤除余液，用去离子水洗剂至中性。在80℃下干燥，在550℃下焙烧5小时，得到半成品催化剂B3。
(3)称取硝酸钯0.0107g，溶于71.5g水中，加入28.80g正己烷，17.16g CTAB，15.6g正戊醇充分搅拌形成微乳液，将半成品催化剂B3加入到制好的微乳液中浸渍80min后，滤除余液，在80℃下干燥，在550℃下焙烧5小时，得到半成品催化剂C3。
(4)取49.5mL去离子水，加入0.126g硝酸银使其完全溶解，调pH为2，将半成品催化剂C3浸渍在所制备的溶液中，摇动10min，在100℃干燥，500℃焙烧5小时，即制得所要的催化剂。
动态光散射法测定步骤(2)制备的微乳液的粒径为78.38nm，步骤(3)制备的微乳液的粒径为77.64nm。
用原子吸收光谱法测定元素含量，得到实施例3所制备的催化剂中Pd含量为0.035％，Ni含量为0.5％，Cu含量为0.5％，Ag含量为0.08％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度150℃，保持4h。
对比例3
催化剂制备：
称取市售双峰孔分布球形氧化铝载体，直径为4mm。经过1092℃焙烧4h后，孔径分布范围分别是20～46nm和85～350nm，吸水率为55％，比表面积为39.58m 2/g，称取该载体100g。
(1)称取0.059g氯化钯盐溶于140mL去离子水中，调pH为2，再将载体加入Pd的盐溶液中，浸渍吸附50minh后，110℃干燥，550℃条件下焙烧5h，得到所需的半成品催化剂A3-1。
(2)称取无水硝酸镍1.59g，硝酸铜1.47g，溶于71.5g水中，加入28.80g正己烷，17.16g CTAB，15.6g正戊醇充分搅拌形成微乳液，将半成品催化剂A3-1加入到制好的微乳液中浸渍80min后，滤除余液，用去离子水洗剂至中性。在80℃下干燥，在550℃下焙烧5小时，得到半成品催化剂B3-1。
(3)取49.5mL去离子水，加入0.126g硝酸银使其完全溶解，调pH为2，将半成品催化剂B3-1浸渍在所制备的溶液中，摇动10min，在100℃干燥，500℃焙烧5小时，即制得所要的催化剂。
动态光散射法测定步骤(2)制备的微乳液的粒径为78.45nm
用原子吸收光谱法测定元素含量，得到对比例3A所制备的催化剂中Pd含量为0.035％，Ni含量为0.5％，Cu含量为0.5％，Ag含量为0.08％。
催化剂的还原：还原气体：氢气，还原空速：100h -1，温度150℃，保持4h。
加氢反应条件：
一段反应器工艺，物料空速2000/h，操作压力3.0MPa，催化剂装填量，200mL。反应器条件如表7所示。
物料组成：
一段反应器入口物料：乙炔0.5％(v/v)，乙烯70％(v/v)，碳三0.8％(v/v)。
表7反应器条件
  500小时前 500小时后
氢/炔 1.5 1.8
入口温度 55 65
表8反应结果
Figure PCTCN2020121914-appb-000006
从表8可以看出，在对比例3A中，1000小时后反应器出口乙炔严重超标，表明催化剂性能已经完全不合格。主要是由于乳液法未负载钯，镍和铜的氧化物在150℃没有还原为金属态，因而没有对副产物的重馏分饱和加氢的作用，导致催化剂结焦较快。
实施例4
载体：采用市售双峰孔分布球形氧化铝载体，直径为3mm。经过1078℃焙烧4h后，双峰孔径分布范围在20～35nm和90～250nm，吸水率57％，比表面积为44.82m 2/g。称取该载体100g。
催化剂制备：
(1)称取无水硝酸镍3.18g，无硝酸铜0.74g，溶于70mL去离子水中，加正己烷35g，加CATB 21g，加正戊醇20g，充分搅拌形成微乳液，将称取的100g高温焙烧过的载体浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h，称为半成品催化剂A4。
(2)称取氯化钯0.069g，溶于100mL去离子水中，调pH为1.8，再将半成品催化剂A4浸渍到已配制的Pd盐溶液中，浸渍60min后，100℃干燥，500℃条件下焙烧6小时，得到半成品催化剂B4。
(3)称取硝酸银0.236g，溶于57mL去离子水中，调pH值为3，将步骤(2)制备的半成品催化剂B4溶解于所配制的配制含银的硝酸银溶液中，摇动，待溶液全部吸收后，140℃干燥，在550℃焙烧6小时，得到半成品催化剂C4。
(4)称取氯化钯0.016g，溶于70mL去离子水中，加正己烷35g，加CATB 21g，加正戊醇20g，充分搅拌形成微乳液，将半成品催化剂C4浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h得到所要的催化剂。
动态光散射测定步骤(1)制备的微乳液乳液的粒径是51.19nm，步骤(4)制备的微乳液乳液的粒径是50.85nm。
由原子吸收光谱法测定制备的催化剂，实施例4中，Pd含量为0.05％，Ni含量为1％，Cu含量为0.25％，Ag含量为0.14％。
催化剂的还原：使用前放置于固定床反应装置中，用摩尔比为N 2:H 2＝1:1的混合气体，在190℃温度，还原处理8h。
对比例4A
催化剂制备：
载体：采用市售双峰孔分布球形氧化铝载体，直径为3mm。经过1078℃焙烧4h后，双峰孔径分布范围在20～35nm和90～250nm，吸水率62％，比表面积为44.82m 2/g。称取该载体100g。
(1)称取称取无水硝酸镍3.18g，无硝酸铜0.74g，溶于70mL去离子水中，加正己烷35g，加CATB 21g，加正戊醇20g，充分搅拌形成微乳液，将称取的100g高温焙烧过的载体浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h，称为半成品催化剂A4-1。
(2)称取氯化钯0.069g，溶于100mL去离子水中，调pH为1.8，再将半成品催化剂A4-1浸渍到已配制的Pd盐溶液中，浸渍60min后，100℃干燥，500℃条件下焙烧6小时，得到半成品催化剂B4-1。
(3)称取硝酸银0.236g，溶于57mL去离子水中，调pH值为3，将步骤(2)制备的半成品催化剂B4-1溶解于所配制的配制含银的硝酸银溶液中，摇动，待溶液全部吸收后，140℃干燥，在550℃焙烧6小时，得到半成品催化剂C4-1。
(4)称取氯化钯0.016g，溶于70mL去离子水中，加正己烷38g，加CATB24g，加正戊醇24g，充分搅拌形成微乳液，将半成品催化剂C4-1浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h得到所要的催化剂。
动态光散射测定步骤(1)制备的微乳液乳液的粒径是52.18nm。
动态光散射测定步骤(4)制备的微乳液乳液的粒径是26.58nm。
由原子吸收光谱法测定制备的催化剂的元素含量，对比例4A的催化剂中，Pd含量为0.05％，Ni含量为1％，Cu含量为0.25％，Ag含量为0.15％。
催化剂的还原：使用前放置于固定床反应装置中，用摩尔比为N 2:H 2＝1:1的混合气体，在190℃温度，还原处理8h。
对比例4B
载体：采用市售双峰孔分布球形氧化铝载体，直径为3mm。经过1078℃焙烧4h后，双峰孔径分布范围在20～35nm和90～250nm，吸水率57％，比表面积为44.82m 2/g。称取该载体100g。
(1)称取称取无水硝酸镍3.18g，无硝酸铜0.74g，溶于70mL去离子水中，加正己烷35g，加CATB21g，加正戊醇20g，充分搅拌形成微乳液，将称取的100g高温焙烧过的载体浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h，称为半成品催化剂A4-2。
(2)称取氯化钯0.069g，溶于100mL去离子水中，调pH为1.8，再将半成品催化剂A4-2浸渍到已配制的Pd盐溶液中，浸渍60min后，100℃干燥，500℃条件下焙烧6小时，得到半成品催化剂B4-2。
(3)称取硝酸银0.236g，溶于57mL去离子水中，调pH值为3，将步骤(2)制备的半成品催化剂B4-2溶解于所配制的配制含银的硝酸银溶液中，摇动，待溶液全部吸收后，140℃干燥，在550℃焙烧6小时，得到半成品催化剂C4-2。
(4)称取氯化钯0.016g，溶于65mL去离子水中，加22.15g正己烷，2.79g CATB，2.75g正丁醇，充分搅拌形成微乳液，将半成品催化剂C4-2浸渍到所制备的微乳液中，摇动90min，滤除余液，在60℃下干燥，在500℃下焙烧6h得到所要的催化剂。
动态光散射测定步骤(1)制备的微乳液乳液的粒径是52.13nm。
动态光散射测定步骤(4)制备的微乳液乳液的粒径是595.09nm。
由原子吸收光谱法测定制备的催化剂元素含量，对比例4B的催化剂中，Pd含量为0.05％，Ni含量为1.0％，Cu含量为0.25％，Ag含量为0.15％。
催化剂的还原：使用前放置于固定床反应装置中，用摩尔比为N 2:H 2＝1:1的混合气体，在190℃温度，还原处理8h。
实施效果
加氢反应条件1
二段反应器工艺，物料空速5000/h，操作压力2.2MPa，催化剂装填量200mL。反应器条件如表9所示。
物料组成：一段反应器入口物料：乙炔1.4％(v/v)，乙烯85％(v/v)，碳三0.5％(v/v)。
表9各段反应器条件
Figure PCTCN2020121914-appb-000007
表10反应结果
Figure PCTCN2020121914-appb-000008
加氢反应条件2
三段反应器工艺：一、二段为绝热反应器，物料空速5000/h，第三段为等温反应器，物料空速11000/h，操作压力2.5MPa，一、二段催化剂装填量1000mL。反应器条件如表11所示。
物料组成：
一段反应器入口乙炔1.5％(v/v)，乙烯93(v/v)。
表11各段反应器条件
  一段 二段 三段
氢/炔 0.8 1.2-1.5 2.0-2.5
各段入口温度 45 55 70
表12反应结果
Figure PCTCN2020121914-appb-000009
从表10及表12中可以看出，对比例4A及4B在反应初期的活性略高于实施例4，表明独立存在的钯具有加氢活性，可以与乙炔反应形成乙烯等，但随反应进行，对比例4A及4B催化剂的活性选择性逐渐较实施例4差，到1000小时后，反应器出口乙炔含量已经不合格。从表12中的结焦量看，其一段反应器的催化剂结焦量很大，表明低氢/炔更易导致催化剂结焦。也表明本催化剂具有更优异的抗结焦性能。
实施例5
载体：采用市售双峰孔分布球形氧化铝-氧化镁载体，氧化镁含量为3％，直径为3mm。经过1065℃焙烧4h后，双峰孔径分布范围在23～47nm和80～380nm，吸水率58％，比表面积为42.38m 2/g。称取该载体100g。
催化剂制备：
(1)称取氯化钯0.051g，溶于80mL去离子水中，调pH为3，再将载体浸渍到已配制的Pd盐溶液中，浸渍120min后，130℃干燥，500℃条件下焙烧4小时，得到半成品催化剂A5。
(2)称取硝酸银0.33g，溶于58mL去离子水中，调pH值为5，将步骤(1)制备的半成品催化剂A5溶解于所配制的配制含银的硝酸银溶液中，摇动，待溶液全部吸收后，100℃干燥，在600℃焙烧4小时，得到半成品催化剂B5。
(3)称取氯化钯0.017g，溶于80mL去离子水中，加正己烷36.00g，加Triton X-10020.88g，加正己醇19.4g，充分搅拌形成微乳液，将制备的半成品催化剂B5浸渍到所制备的微乳液中，摇动180min，滤除余液，在70℃下干燥，在500℃下焙烧4h，称为半 成品催化剂C5。
(4)称取氯化镍1.648g，硝酸铜2.175g，溶于80mL去离子水中，加正己烷36.00g，加Triton X-100 20.88g，加正己醇19.60g，充分搅拌形成微乳液，将步骤(2)制备的半成品催化剂C5浸渍到所制备的微乳液中，摇动180min，滤除余液，在70℃下干燥，在500℃下焙烧4h，得到所要的催化剂。
动态光散射测定制备的步骤(1)微乳液乳液的粒径是65.0nm，步骤(4)微乳液乳液的粒径是65.24nm。
由原子吸收光谱法测定制备的催化剂元素含量，实施例5的催化剂中，Pd含量为0.04％，Ni含量为0.75％，Cu含量为0.75％，Ag含量为0.21％。
催化剂的还原：使用前放置于固定床反应装置中，用摩尔比为N2:H2＝1:1的混合气体，在180℃温度，还原处理8h。
对比例5
催化剂制备条件与实施例5相同，不同的是制备步骤无乳液法负载Pd。
载体：采用市售双峰孔分布球形氧化铝-氧化镁载体，氧化镁含量为3％，直径为3mm。经过1000℃焙烧4h后，双峰孔径分布范围在23～47nm和80～380nm，吸水率58％，比表面积为40m 2/g。称取该载体100g。
(2)称取氯化钯0.069g，溶于80mL去离子水中，调pH为3，再将载体浸渍到已配制的Pd盐溶液中，浸渍120min后，130℃干燥，500℃条件下焙烧4小时，得到半成品催化剂A5-1。
(2)称取硝酸银0.33g，溶于58mL去离子水中，调pH值为5，将步骤(1)制备的半成品催化剂A5-1溶解于所配制的配制含银的硝酸银溶液中，摇动，待溶液全部吸收后，100℃干燥，在600℃焙烧4小时，得到半成品催化剂B5-1。
(3)称取氯化镍1.648g，硝酸铜2.175g，溶于80mL去离子水中，加正己烷36.00g，加Triton X-100 20.88g，加正己醇19.4g，充分搅拌形成微乳液，将步骤(2)制备的半成品催化剂B5-1浸渍到所制备的微乳液中，摇动180min，滤除余液，在70℃下干燥，在500℃下焙烧4h，得到所要的催化剂。
动态光散射测定步骤(4)制备的微乳液乳液的粒径是65.20nm。
由原子吸收光谱法测定制备的催化剂，对比例5中，Pd含量为0.04％，Ni含量为0.75％，Cu含量为0.75％，Ag含量为0.21％。
催化剂的还原：使用前放置于固定床反应装置中，用摩尔比为N 2:H 2＝1:1的混合气 体，在180℃温度，还原处理8h。
实施效果
加氢反应条件
三段反应器工艺：各段为绝热反应器，物料空速11000/h，操作压力2.3MPa，催化剂装填量1000mL。反应器条件如表13所示。
物料组成：一段反应器入口乙炔：1.5％(v/v)，乙烯70％(v/v)。
表13各段反应器条件
  一段 二段 三段
氢/炔 1.5 1.4 1.5
各段入口温度 45 55 70
表14反应结果
Figure PCTCN2020121914-appb-000010
表14中，对比例5的催化剂1000小时后，尽管三段反应器入口乙炔含量仅0.12％，反应器出口乙炔含量达到40ppm。表明三段低氢/炔对脱除乙炔不利，但实施例5的催化剂，仍然能够将乙炔完全转化，表明本发明的催化剂，在经过1000小时运行后，性能衰减很小。而对比例5的催化剂要差的多，原因是未用乳液法负载Pd，导致镍和铜不能在180℃被还原。

Claims (20)

  1. 一种碳二馏分炔烃选择加氢方法，其中：加氢物料为来自前脱乙烷塔塔顶的碳二馏分，进入固定床反应器后进行气相加氢脱除乙炔，该选择性加氢反应的工艺条件为：反应器入口温度35～100℃，压力1.5～3.0MPa，气体体积空速2000～11000h -1；加氢反应所使用的催化剂以Al 2O 3为载体，具有双峰孔径分布特征，孔径分别在15～50nm及80～500nm；所述的催化剂至少含有活性组分Pd、Ni、Cu，以载体的质量100％计，所述的催化剂含0.03～0.09％的Pd，0.5～5％的Ni，Cu：Ni＝0.1～1:1，Ni、Cu及部分Pd的负载采用微乳液负载，所述的部分Pd的含量是所述的Ni+Cu含量的1/100～1/200，所述的微乳液的粒径在50～500nm。
  2. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，所述的催化剂还含有0.08～0.21％的Ag，Ag通过溶液负载。
  3. 根据权利要求1或2所述的碳二馏分炔烃选择加氢方法，其中，所述Pd的含量为0.035～0.075％，微乳液负载的部分Pd的含量是所述的Ni+Cu含量的1/110～1/200。
  4. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，所述催化反应物料中乙烯占65～93％(v/v)，乙炔0.2～2.5％(v/v)。
  5. 根据权利要求4所述的碳二馏分炔烃选择加氢方法，其中，所述催化反应物料中乙烯占65～93％(v/v)，其次为乙烷5～35％(v/v)，乙炔0.3～2.5％(v/v)，碳三馏分0.01～0.8％(v/v)。
  6. 根据权利要求1、4或5所述的碳二馏分炔烃选择加氢方法，其中，使用固定床反应器单段反应器加氢时，反应器入口氢/炔1.3～2.2，优选1.3-1.8。
  7. 根据权利要求1、4-6任一项所述的碳二馏分炔烃选择加氢方法，其中，使用固定床反应器两段反应器加氢时，一段反应器入口氢/炔1.0～1.4，二段反应器入口氢/炔1.5～2.5。
  8. 根据权利要求1、4-7任一项所述的碳二馏分炔烃选择加氢方法，其中，使用固定床反应器三段反应器串联加氢时，一段反应器入口氢/炔0.5～1.5，二段反应器入口氢/炔1.0～2.0，三段反应器入口氢/炔1.4～3.0，优选的是，一段反应器入口氢/炔0.8～1.5，二段反应器入口氢/炔1.2～1.6，三段反应器入口氢/炔1.5～2.5。
  9. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，所述催化剂在加氢前，需要进行还原，还原温度为150～200℃。
  10. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，所述催化剂的微乳 液方式负载过程包括：将前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液，其中油相为烷烃或环烷烃，表面活性剂为离子型表面活性剂和\或非离子型表面活性剂，助表面活性剂为有机醇。
  11. 根据权利要求10所述的碳二馏分炔烃选择加氢方法，其中，水相/油相的重量比为是2.0～3.0；所述的表面活性剂/助表面活性剂的重量比是1～1.2；所述的表面活性剂/油相的重量比为0.15～0.6。
  12. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，油相为C 6～C 8饱和烷烃或环烷烃；表面活性剂为离子型表面活性剂和\或非离子型表面活性剂；助表面活性剂为C 4～C 6醇类。
  13. 根据权利要求12所述的碳二馏分炔烃选择加氢方法，其中，所述油相为环己烷或正己烷。
  14. 根据权利要求12所述的碳二馏分炔烃选择加氢方法，其中，所述表面活性剂为非离子型表面活性剂。
  15. 根据权利要求14所述的碳二馏分炔烃选择加氢方法，其中，所述表面活性剂为聚乙二醇辛基苯基醚或十六烷基三甲基溴化铵。
  16. 根据权利要求12所述的碳二馏分炔烃选择加氢方法，其中，所述助表面活性剂为正丁醇和/或正戊醇。
  17. 根据权利要求1或2所述的碳二馏分炔烃选择加氢方法，其中，所述的催化剂的制备步骤中，微乳液法负载Pd是在Ni、Cu之后。
  18. 根据权利要求2所述的碳二馏分炔烃选择加氢方法，其中，所述的催化剂的制备步骤中，溶液法负载Ag是在溶液法负载Pd之后。
  19. 根据权利要求1所述的碳二馏分炔烃选择加氢方法，其中，所述催化剂的制备具体包含以下步骤：
    (1)将Ni和Cu的前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液；制备微乳液的条件是：表面活性剂/助表面活性剂的重量比为1～1.2，水相/油相的重量比为2.0～3.0，表面活性剂/油相的重量比为0.15～0.6；将载体加入到制好的微乳液中浸渍0.5～4小时后，滤除余液；干燥后，在400～600℃下焙烧，得到半成品催化剂A；
    (2)将Pd前驱体盐溶于水中，加入油相、表面活性剂和助表面活性剂，充分搅拌形成微乳液；制备微乳液的条件是：表面活性剂和助表面活性剂的重量比为1～1.2，水 相和油相的重量比为2.0～3.0，表面活性剂和油相的重量比为0.15～0.6；将半成品催化剂A加入到制好的微乳液中浸渍0.5～4小时后，滤除余液；干燥后，在400～600℃下焙烧，得到半成品催化剂B；
    (3)将Pd的前驱体盐溶于水，调pH为1.5～2.5，再将半成品催化剂B加入Pd的盐溶液中，浸渍吸附0.5～4h后，干燥后在400～600℃条件下焙烧，得到成品催化剂。
  20. 根据权利要求2所述的碳二馏分炔烃选择加氢方法，其中，所述催化剂的制备具体包含以下步骤：
    (1)将Ni及Cu的前驱体盐溶于水中，加入计量的油相、表面活性剂及助表面活性剂，充分搅拌形成微乳液，控制微乳液粒径大于50nm小于500nm，将载体加入到制好的微乳液中浸渍0.5～4小时后，滤除余液，用去离子水洗至中性，干燥焙烧得到半成品催化剂A；
    (2)将Pd的前驱体盐溶于去离子水，加入计量的油相、表面活性剂及助表面活性剂，充分搅拌形成微乳液，充分搅拌形成微乳液，控制微乳液粒径大于50nm小于500nm；将半成品A加入到制好的微乳液中浸渍0.5～4小时后，滤除余液，用去离子水洗至中性，干燥焙烧得到半成品催化剂B；
    (3)将Pd的前驱体盐溶于去离子水，再将半成品催化剂B加入Pd的盐溶液中，浸渍10-120分钟后，干燥，焙烧得到半成品催化剂C；
    (4)将Ag的前驱体盐溶于水，得到的水溶液的量与半成品催化剂C饱和吸水量相当，再将半成品C加入Ag的盐溶液中，待溶液完全吸收后，干燥、焙烧得到所要的催化剂。
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