Selective hydrogenation method for C1-C3 fractions

Abstract

The invention provides a selective hydrogenation method for C1-C3 fractions, the C1-C3 fractions come from the top of a depropanizer of an ethylene device, and the process conditions of the hydrogenation reaction are as follows: the inlet temperature of a reactor is 90-130 DEG C, and the gas volume space velocity is 6000-20000h <-1 >; in the C1-C3 fractions, the content of H2 is 10%-30%, the content of C2H4 is 25%-40%, the content of C2H2 is 0.4%-0.9%, the content of C3H6 is 5%-11%, the content of PDMA is 0.2%-1.2%, the content of CO is 0.03%-0.2%, the content of butadiene is less than or equal to 0.2%, and the balance is methane, ethane and propane. According to the hydrogenation method, non-noble metal Fe is adopted as a catalyst of a main active component, and process parameter control is combined, so that the CO fluctuation resistance of the catalyst is improved, the selective hydrogenation efficiency of C1-C3 fractions is ensured, and meanwhile, the cost of the catalyst is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogenation, and in particular relates to a method for selective hydrogenation of C1-C3 fractions. Background Art

[0002] Ethylene obtained by steam cracking of petroleum hydrocarbons (such as ethane, naphtha, diesel, hydrogenated tail oil, etc.) contains 0.2%-2.5% acetylene by mass. When used for polymerization, the acetylene in ethylene will reduce the activity of the polymerization catalyst and affect the physical properties of the polymer, so it must be removed. At present, the industry generally adopts the method of selective hydrogenation to remove acetylene, and the catalysts used are mainly precious metal catalysts such as Pd, Pt, and Au. In order to ensure that the ethylene generated by acetylene hydrogenation and the original ethylene in the raw material do not continue to hydrogenate to generate ethane and do not cause ethylene loss, it is necessary to ensure that the catalyst has a high hydrogenation selectivity in order to obtain better economic benefits.

[0003] According to the relative position of the C2 hydrogenation reactor and the demethanization, C2 hydrogenation is divided into pre-hydrogenation and post-hydrogenation. The C2 pre-hydrogenation reactor is before the demethanizer, and the hydrogenated materials generally contain C1, C2 fractions and C3 fractions. In addition to hydrogen and methane, the C1 fraction also contains CO. Generally, the material composition of pre-depropanization hydrogenation is: H2 15% ~ 30%, C2H 64% ~ 10%, C2H4 25% ~ 40%, C2H2 0.4% ~ 0.7%, C3H 68% ~ 11%, C3H 81% ~ 2%, propyne 0.1% ~ 0.6%, propadiene 0.1% ~ 0.6%, CO 0.04% ~ 0.15%.

[0004] Precious metal catalysts have high activity, but they are prone to generate green oil during use, which causes the catalyst to coke and deactivate, affecting the stability and service life of the catalyst. For example, Chinese patent document CN101664682 discloses a non-precious metal supported selective hydrogenation catalyst and its preparation method and application, including a carrier and a main active component and an auxiliary active component supported on the carrier, wherein the main active component is Ni, and 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 present in amorphous form, with an average particle size of <10nm, and the carrier is a non-oxidizing porous material; and the catalyst is prepared by microemulsion method.

[0005] The selective hydrogenation catalyst for alkynes and dienes is obtained by loading a noble metal such as palladium on a porous inorganic material carrier (e.g., US4762956). In order to increase the selectivity of the catalyst and reduce the catalyst deactivation caused by the green oil produced by the oligomerization reaction during hydrogenation, the prior art adopts a method of adding, for example, a Group IB element as a co-catalyst component in the catalyst: Pd-Au (US4490481), Pd-Ag (US4404124), Pd-Cu (US3912789), or adding an alkali metal or alkaline earth metal (US5488024), etc. The carrier used has aluminum oxide, silicon dioxide (US5856262), honeycomb philadelphite (CN1176291), etc. For example, U.S. Patent Document US4404124 prepared a selective hydrogenation catalyst with a palladium shell distribution of the active component by a step-by-step impregnation method, which can be applied to the selective hydrogenation of carbon two and carbon three fractions to eliminate acetylene in ethylene and propyne and propadiene in propylene. US Patent Document US5587348 discloses that alumina is used as a carrier, the role of silver and palladium as co-catalysts is adjusted, and alkali metals and chemically bonded fluorine are added to prepare a carbon dihydrogenation catalyst with excellent performance. The catalyst has the characteristics of reducing green oil production, improving ethylene selectivity, and reducing the amount of oxygen-containing compounds produced. US Patent Document US5519566 discloses a method for preparing a silver and palladium catalyst by wet reduction, and a silver and palladium two-component selective hydrogenation catalyst is prepared by adding an organic or inorganic reducing agent to the impregnation solution.

[0006] In the above traditional carbon dihydrogenation process, the catalysts used are mostly prepared by impregnation method, and their active phases are mostly Pd and Ag bimetallic. This method has the following disadvantages: (1) Affected by the pore structure of the carrier, the dispersion of active components cannot be precisely controlled and is highly random. (2) Affected by the surface tension and solvation effect of the impregnation liquid, the metal active component precursors are deposited on the carrier surface in the form of aggregates and cannot form a uniform distribution. (3) Carbon dihydrogenation has high requirements for catalyst selectivity. The traditional preparation method promotes the role of its auxiliary agent by increasing the amount of Ag, which leads to the obstruction of hydrogen transfer, the increase of the possibility of polymerization reaction, and the increase of green oil production, which affects the life of the catalyst. The occurrence of the above three phenomena can easily lead to poor dispersion of metal active components, low reaction selectivity, and high green oil production, which in turn affects the overall performance of the catalyst.

[0007] In view of the above problems, Chinese patent document CN102205243B discloses a catalyst used in the process of carbon dihydrogenation, which forms a polymer coating layer on the surface of the carrier with a certain thickness by adsorbing a specific polymer compound on the carrier, and reacting the polymer with a compound with a functional group to make it have a functional group that can be complexed with the active component, and the active component undergoes a complex reaction on the functional group on the surface of the carrier to ensure that the active component is orderly and highly dispersed. However, the amount of polymer compound adsorbed by the carrier will be limited by the number of hydroxyl groups of alumina by chemical adsorption of the hydroxyl group of alumina; the complexation of the functionalized polymer with Pd is not strong, and sometimes the active component loading does not meet the requirements, and some active components remain in the impregnation solution, resulting in an increase in the cost of the catalyst.

[0008] In order to improve the anti-coking performance of the catalyst and reduce the surface coking degree of the catalyst, in recent years, a carbon two selective hydrogenation catalyst and a preparation method using a bimodal pore carrier and a microemulsion method to load the active component have been disclosed. For example, Chinese patent document CN104096572B discloses a selective hydrogenation catalyst, whose carrier is mainly alumina and has a bimodal pore distribution structure, wherein the pore size of the small pore is within 50nm and the pore size of the large pore is 60-800nm. Taking the mass of the catalyst as 100%, the catalyst contains 0.01-0.5% by weight of Pd, which is a shell distribution with a thickness of 1-500um; it contains 0.2-5% by weight of Ni, and the anti-coking component Ni is controlled by a microemulsion method to control the particle size of the microemulsion to be larger than the particle size of the small pores of the carrier, so that Ni is mainly distributed in the large pores of the carrier. Chinese patent document CN104096573B discloses a method for preparing a hydrogenation catalyst, wherein the catalyst carrier is mainly alumina and has a bimodal pore distribution structure. The catalyst contains Pd and Ni dual active components. When preparing the catalyst, the anti-coking component Ni is introduced into the macropores of the carrier in the form of a microemulsion, and the active component Pd is mainly distributed on the surface of the carrier, especially in the small pores. Chinese patent document CN104098426A discloses a carbon distillate selective hydrogenation method suitable for a pre-depropanization pre-hydrogenation process. The selective hydrogenation catalyst used in this method has a carrier of alumina or mainly alumina, and has a bimodal pore distribution structure, containing dual active components Pd and Ni, and the anti-coking component Ni is mainly distributed in the macropores. Although the above-mentioned hydrogenation catalysts improve the anti-coking performance of the catalyst, the single component Ni in the macropores of the catalyst carrier has a reduction temperature of more than 500°C, and is reduced at this temperature, so that the catalyst active component Pd aggregates, which greatly reduces the catalyst activity. In order to compensate for the loss of catalyst activity, the amount of active component needs to be increased, which leads to a decrease in catalyst selectivity and a decrease in active component utilization.

[0009] Chinese patent document CN112675872A discloses a pre-deethanization pre-hydrogenation catalyst for carbon distillation, wherein the carrier is alumina or mainly alumina and has a bimodal pore distribution structure, the specific surface area of ​​the catalyst is 4-12m2 / g, the pore diameter of the small pores is 55-72nm, the pore diameter of the macropores is 300-640nm, the catalyst contains at least Pd, Ni, and Cu, wherein Pd and Ni are loaded in two ways, microemulsion and solution, Cu is loaded in microemulsion, based on the mass of the catalyst as 100%, the content of Pd loaded in the solution method is 0.03-0.04%, the weight ratio of Ni loaded in the solution method to Pd loaded in the solution method is 2.5-3.5, the content of Ni loaded in the microemulsion method is 1.0-4.5%, and the weight ratio of Cu to Ni loaded in the microemulsion method is 0.1-1.0; wherein Ni, Cu, and Pd loaded in the microemulsion method are mainly distributed in the macropores of 300-640nm on the carrier. However, the content of Pd, the main active component of the catalyst, is relatively high, and the catalyst cost is high.

[0010] Chinese patent document CN112939718B discloses a method for removing acetylene in a pre-depropanization pre-hydrogenation process, wherein the top effluent from the pre-depropanizer in the ethylene unit enters an adiabatic bed reactor for selective hydrogenation to remove acetylene and dienes therein, and the reaction conditions are: inlet temperature of 50-100°C for the first stage, 50-100°C for the second stage, 50-100°C for the third stage, pressure of 1.5-4.0 MPa, and space velocity of 10000-20000 h-1; the preferred hydrogenation conditions are: inlet temperature of 53-95°C for the first stage, 55-95°C for the second stage, 60-95°C for the third stage, pressure of 2.8-3.8 MPa, and space velocity of 1200 0~18000h-1; The catalyst contains at least active components Pd, Au, Ni, and Cu, wherein Pd is loaded in two ways, microemulsion and solution, Ni and Cu are loaded in microemulsion, Au is loaded in solution, the content of Pd loaded in solution is 0.035~0.065%, preferably 0.037~0.045%, the weight ratio of Au to solution loading is 1.3~3.0, preferably 1.5~2.5, the content of Ni is 0.5~8.0%, preferably 2.0~5.8%, the weight ratio of Cu to Ni is 0.1~0.9, preferably 0.3~0.8. The content of Pd loaded in microemulsion is 1 / 150~1 / 250 of the content of Ni+Cu, the catalyst carrier is alumina or mainly alumina, and has a bimodal pore distribution structure. However, the main active components of the catalyst are Pd and Au, both of which have high contents, and the catalyst cost is high. Summary of the invention

[0011] The object of the present invention is to provide a method for selective hydrogenation of C1-C3 fractions, which adopts a catalyst with non-precious metal Fe as the main active component, thereby improving the catalyst's ability to resist CO fluctuations and ensuring the selective hydrogenation efficiency of C1-C3 fractions, while reducing the catalyst cost.

[0012] To achieve the above object, the present invention adopts the following technical solution:

[0013] A method for selective hydrogenation of C1-C3 fractions, wherein the C1-C3 fractions are from the top of a depropanizer of an ethylene unit, and the C1-C3 fractions are selectively hydrogenated with hydrogen in a fixed bed reactor containing a catalyst. The process conditions of the selective hydrogenation reaction are: a reactor inlet temperature of 90-130°C, a gas volume space velocity of 6000-20000h / min -1 ; The volume content of CO in the C1-C3 fraction is 0.03% to 0.2%;

[0014] The catalyst used in the selective hydrogenation reaction is alumina or mainly alumina, with a specific surface area of ​​3 to 15 m 2 / g, having a bimodal pore size distribution characteristic, with a small pore size of 30-80nm and a large pore size of 300-800nm; the active components include Pd, Ni and Fe, Pd is loaded by both microemulsion method and solution method, Ni is loaded by microemulsion method, and Fe is loaded by solution method; and the solution method loads Pd after the solution method loads Fe, and the microemulsion method loads Pd after the microemulsion method loads Ni; the microemulsion method loads Pd and Ni in the large pores, and the solution method loads Fe and Pd in ​​the small pores;

[0015] Taking the mass of the carrier as 100%, the Ni content is 0.5% to 2.5%, the Fe content is 0.5% to 1.5%, the Pd content loaded by the solution method is 0.007% to 0.015%; the Pd content loaded by the microemulsion method is 0.002 to 0.007 of the Ni content;

[0016] The catalyst is reduced at 180-230° C. before being put into the selective hydrogenation reaction; preferably, the reduction is performed for 4-12 hours, and the reduction space velocity is 100-400 / h.

[0017] In the selective hydrogenation method provided by the present invention, Fe in the catalyst is the main active component of the selective hydrogenation. During the hydrogenation process, CO in the crude hydrogen will also participate in the reaction, mainly undergoing formylation reaction with hydrogen and olefins to generate carbonyl-containing compounds. The adsorption strength of these carbonyl-containing compounds on alumina is higher than that of olefins, and they stay on the catalyst for a longer time, resulting in a decrease in the hydrogenation activity of Fe.

[0018] Moreover, the catalyst needs to be reduced before the hydrogenation reaction. Both Pd and Ni components need to be reduced from an oxidized state to a metallic state under the action of hydrogen. The reduction temperature of Pd oxide is no higher than 150°C, and the reduction temperature of Ni oxide is 350-400°C. This temperature is too high for Pd, which can easily cause the aggregation of active centers and form larger active centers, thereby reducing the activity selectivity of the hydrogenation reaction.

[0019] Therefore, in this hydrogenation process, two key issues need to be addressed: 1) the hydrogenation activity of Fe; 2) the growth of Pd particles caused by the reduction temperature of 350-400°C.

[0020] The inventors have found that after loading Fe by solution method, a small amount of Pd is then loaded by solution method, and the hydrogenation activity is greatly improved. It is speculated that the small amount of Pd loaded by solution plays a role in hydrogenation transfer rate, thereby accelerating the hydrogenation reaction. The inventors have also found that after loading Ni by microemulsion method, a small amount of Pd is loaded by microemulsion method, and the reduction temperature of NiO can be reduced to 180-230°C.

[0021] In the above hydrogenation method provided by the present invention, non-precious metal iron is used as the main active component, and a catalyst having a carrier with a bimodal pore size distribution (large pores loaded with Ni and a small amount of Pd, small pores loaded with Fe and a small amount of Pd) is used. In addition to acetylene, ethylene and ethane, the hydrogenation material also contains hydrogen, methane and CO. In the hydrogenation process, the selective hydrogenation of acetylene mainly occurs in the small pores loaded with Fe and a small amount of Pd. The by-products generated in the hydrogenation reaction are easier to enter the macropores of the catalyst due to their larger volume. Under the action of the Ni active center, the by-products undergo saturated hydrogenation to become alkanes, and no polymerization reaction occurs, thereby greatly reducing the rate of coking.

[0022] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, based on the total volume of the C1-C3 fraction as 100%, the H2 content is 10%-30%, the C2H4 content is 25%-40%, the C2H2 content is 0.4%-0.9%, the C3H6 content is 5%-11%, the PDMA content is 0.2%-1.2%, the CO content is 0.03%-0.2%, the butadiene content is ≦0.2%, and the remainder is methane, ethane and propane.

[0023] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, the selective hydrogenation reaction is single-stage hydrogenation, two-stage hydrogenation or three-stage hydrogenation.

[0024] Optionally, in the above-mentioned C1~C3 fraction selective hydrogenation method provided by the present invention, the process of loading Ni by microemulsion method or loading Pd by microemulsion method includes the following steps: dissolving Ni precursor salt or Pd precursor salt in water to obtain an aqueous phase, and then adding an oil phase, a surfactant and a co-surfactant to the aqueous phase, and stirring to form a microemulsion.

[0025] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, microemulsion loading refers to traditional impregnation loading, and its impregnation liquid is a microemulsion; solution loading refers to traditional impregnation loading, and its impregnation liquid is a solution. The process of loading Ni by microemulsion or loading Pd by microemulsion recommended by the present invention comprises the following steps: dissolving a precursor salt of Ni or a precursor salt of Pd in ​​water to obtain an aqueous phase, and then adding an oil phase, a surfactant and a co-surfactant to the aqueous phase, and stirring to form a microemulsion.

[0026] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, the particle size of the microemulsion is not less than the maximum pore size of the small pores of the carrier and not higher than the maximum pore size of the large pores, for example, the particle size of the microemulsion is 300-800nm. For a specific catalyst carrier with a bimodal pore size distribution, the pore size of its small pores and the pore size of its large pores are respectively a size range, and the particle size of the microemulsion is not less than the maximum pore size of the small pores and not higher than the maximum pore size of the large pores means that the particle size of the microemulsion prepared during loading is not lower than the upper limit of the pore size range of the small pores of a specific catalyst carrier and is not higher than the upper limit of the pore size range of the large pores of the catalyst carrier. Preferably, the particle size of the microemulsion is greater than 300nm (including 300nm) and less than 800nm ​​(including 800nm).

[0027] The particle size of the microemulsion is larger than the pore size of the small pores but smaller than the maximum pore size of the large pores. Due to spatial resistance, these components can only enter the large pores, so active centers with different hydrogenation effects are formed in the large and small pores of the catalyst. The large pores contain active centers composed of Ni, which have a good hydrogenation saturation effect on the green oil molecules, so that the green oil molecules entering the large pores will no longer polymerize, so they will gradually move out of the reactor and are not easy to form coke.

[0028] In the process of loading Ni or Pd by the microemulsion method recommended by the present invention, the mass ratio of the water phase to the oil phase is 2.0 to 4.5, the mass ratio of the surfactant to the oil phase is 0.10 to 0.4, and the mass ratio of the surfactant to the co-surfactant is 1.0 to 1.5.

[0029] Optionally, in the above-mentioned microemulsion method for loading Ni or microemulsion method for loading Pd recommended by the present invention, the oil phase is a C6-C8 saturated alkane or cycloalkane, preferably cyclohexane or n-hexane;

[0030] The surfactant is an ionic surfactant and / or a nonionic surfactant, preferably a nonionic surfactant, more preferably polyethylene glycol octylphenyl ether or hexadecyltrimethylammonium bromide;

[0031] The co-surfactant is an organic alcohol; preferably C4-C6 alcohols, more preferably n-butanol and / or n-pentanol.

[0032] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, the order of loading the active component into the carrier comprises the following steps:

[0033] Microemulsion loading of Ni, solution method loading of Fe, solution method loading of Pd, microemulsion method loading of Pd; or

[0034] Microemulsion loading of Ni, solution method loading of Fe, microemulsion method loading of Pd, solution method loading of Pd; or

[0035] Solution method loading Fe, microemulsion loading Ni, solution method loading Pd, microemulsion method loading Pd; or

[0036] Microemulsion loading of Ni, microemulsion method loading of Pd, solution method loading of Fe, solution method loading of Pd.

[0037] Specifically, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, the preparation of the catalyst comprises the following steps:

[0038] (1) Dissolve the Ni precursor salt in water, add the oil phase, surfactant and co-surfactant, and stir thoroughly to form a microemulsion; the conditions for preparing the microemulsion are: the mass ratio of the water phase to the oil phase is 2.0-4.5, the mass ratio of the surfactant to the oil phase is 0.10-0.4, and the mass ratio of the surfactant to the co-surfactant is 1.0-1.5. Add the calcined carrier to the prepared microemulsion and immerse it. After the emulsion is completely absorbed, dry it and calcine it at 400-600°C to obtain a semi-finished catalyst A;

[0039] (2) dissolving the Fe precursor salt in deionized water, the volume of the solution being equivalent to the water absorption capacity of the carrier, and then adding the semi-finished catalyst A to the prepared solution. After the solution is completely absorbed, drying and calcining at 250-600° C. to obtain the semi-finished catalyst B;

[0040] (3) dissolving the precursor salt of Pd in ​​water, the volume of the solution being equal to the water absorption capacity of the carrier, adjusting the pH to 1.2-2.7, and then adding the semi-finished catalyst B to the Pd salt solution. After the solution is completely absorbed, drying and calcining at 400-550° C. to obtain the semi-finished catalyst C;

[0041] (4) dissolving a precursor salt of Pd in ​​water, adding an oil phase, a surfactant and a co-surfactant, and stirring thoroughly to form a microemulsion; the conditions for preparing the microemulsion are: the mass ratio of the water phase to the oil phase is 2.0 to 4.5, the mass ratio of the surfactant to the oil phase is 0.10 to 0.4, and the mass ratio of the surfactant to the co-surfactant is 1.0 to 1.5; adding the semi-finished catalyst C to the prepared microemulsion for immersion, and after the solution is completely absorbed, drying, and calcining at 400 to 550° C. to obtain the desired catalyst of the semi-finished catalyst;

[0042] Among them, step (1) and step (2) can be interchanged; step (3) and step (4) can be interchanged, step (4) is after step (1), and step (3) is after step (2).

[0043] In each of the above steps, the precursor salt of the metal is a soluble salt, which may be its nitrate, chloride or other soluble salt. For example, the precursor salt of Pd may be selected from any soluble palladium salt such as palladium chloride and palladium nitrate; the precursor salt of Ni may be selected from any soluble nickel salt such as nickel chloride and nickel nitrate; the precursor salt of Fe may be selected from any soluble iron salt such as ferric nitrate and ferric chloride.

[0044] Optionally, in the above-mentioned C1-C3 fraction selective hydrogenation method provided by the present invention, before the catalyst is put into the selective hydrogenation reaction, the reducing atmosphere is pure hydrogen, or a mixture of hydrogen and nitrogen, and the reduction time is 2 to 15 hours.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] Beneficial effect 1: The selective hydrogenation method of C1-C3 fractions provided by the present invention has good hydrogenation selectivity and long-cycle operation characteristics, which not only reduces the catalyst preparation cost, but also improves the target product yield and greatly reduces the coking rate. Specifically, the main active component of the catalyst used is non-precious metal Fe, which reduces the Pd content, reduces the catalyst cost, and makes the catalyst easier to produce and replace. As the main active component, Fe has a lower adsorption strength for CO than the main active component Pd of the traditional catalyst, which reduces the sensitivity of the reaction temperature to the CO content during the hydrogenation process, which is beneficial to the stability of the acetylene removal reaction. Moreover, since the catalyst cost is greatly reduced, the reaction can be operated at a lower space velocity to ensure that the reaction results are qualified.

[0047] Beneficial effect 2: In the selective hydrogenation method of C1-C3 fraction provided by the present invention, the main active component of the catalyst used is Fe, and a small amount of Pd plays the role of adsorbing and transferring hydrogen. Due to the reduction of the precious metal content, the catalyst cost is greatly reduced. And the ability of the catalyst to resist CO fluctuations is improved. Specifically, the outer electron configuration of the main active component Fe is close to half full, and its empty orbital can accept π electrons or lone pairs of electrons from olefin molecules or CO. Therefore, CO can play a role in regulating the selectivity of the active center. In addition, the number of empty orbitals of the outer layer of Fe atoms is lower than that of Pd atoms, and the adsorption strength of CO on Fe atoms is lower than that of Pd atoms. Therefore, the active center composed of Fe as the main active component is less sensitive to CO content fluctuations than the active center composed of Pd as the main active component. Therefore, the active center of the former no longer needs to add Ag, so it can also reduce the cost of catalyst preparation, and the adaptable CO range is larger.

[0048] More importantly, when Pd is used as a hydrogenation catalyst, there is a risk of temperature runaway when the temperature exceeds 130°C. The reason is that at this temperature, ethylene may undergo polymerization reaction, releasing a large amount of reaction heat, causing the temperature in the reactor to rise rapidly. In addition, there is a large amount of hydrogen in the material, which accelerates the hydrogenation reaction and polymerization reaction, so that the temperature cannot be controlled and the temperature runs away. In the present invention, the active center composed of Fe as the main active component is used, and its hydrogenation activity is relatively low. After the temperature exceeds 120°C, it will not quickly cause ethylene self-polymerization, and it is not easy to cause reactor runaway. Therefore, the temperature in its reactor can reach up to 135°C, that is, its active temperature range is also wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is the particle size distribution diagram of the iron microemulsion prepared in step (1) of Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0051] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0052] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

[0053] The experimental instruments, raw materials and chemical reagents involved in the following examples and comparative examples are shown in Tables 1 and 2 below.

[0054] Table 1 Experimental instruments

[0055]

[0056]

[0057] Table 2 Experimental raw materials and chemical reagents

[0058]

[0059] Analytical test methods:

[0060] Specific table: GB / T-5816;

[0061] Content of active components in catalyst: atomic absorption method;

[0062] Ni, Pd microemulsion particle size distribution: dynamic light scattering particle size analyzer;

[0063] Agilent 7890A gas chromatograph was used to measure the hydrogen and acetylene contents at the reactor outlet and inlet.

[0064] The conversion rate and selectivity are calculated according to the following formula:

[0065] Acetylene conversion rate (%) = [(acetylene content at reactor inlet - acetylene content at reactor outlet) / acetylene content at reactor inlet] × 100%

[0066] Ethylene selectivity = [(ethylene content at reactor outlet - ethylene content at reactor inlet) / (acetylene content at reactor inlet - acetylene content at reactor outlet)] × 100%

[0067] The initial conversion rate refers to the acetylene conversion rate within 24 hours after the reactor is charged.

[0068] The present invention is further described below by way of examples, but it is not intended that the present invention is limited thereto.

[0069] Example 1

[0070] Carrier: Weigh a commercially available bimodal pore distribution spherical carrier with a diameter of 4 mm. After calcination at 1350°C, the pore size distribution ranges are 45-65 nm and 410-560 nm, respectively, the water absorption rate is 35%, and the specific surface area is 3 m 2 / g, weigh 100g of the carrier.

[0071] Catalyst preparation:

[0072] (1) Weigh 3.11 g of nickel nitrate, dissolve it in 30 ml of deionized water, add 14 g of cyclohexane, 3.08 g of Triton X-100, and 2.57 g of n-butanol, stir thoroughly to form a microemulsion, and impregnate 100 g of the carrier into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 60° C. and calcine it at 600° C. for 5 h to obtain a semi-finished catalyst A.

[0073] (2) Weigh 2.17 g of ferric nitrate and dissolve it in 35 g of deionized water, then add the semi-finished catalyst A to the Ni salt solution, and after the solution is completely absorbed, age it for 4 hours, dry it at 120° C., and calcine it at 400° C. for 6 hours to obtain the semi-finished catalyst B;

[0074] (3) Weigh 16.67 mg of palladium chloride and dissolve it in 35 g of deionized water, adjust the pH to 1.5, then add the semi-finished catalyst B to the Pd salt solution, age it for 10 hours, dry it at 120° C., and calcine it at 400° C. for 4 hours to obtain a semi-finished catalyst C;

[0075] (4) Weigh 8.33 mg of palladium chloride and dissolve it in 30 ml of deionized water. Add 14 g of cyclohexane, 3.08 g of Triton X-100, and 2.57 g of n-butanol to 30 ml of deionized water. Impregnate the semi-finished catalyst C into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 60° C. for 6 hours and calcine it at 450° C. for 4 hours to obtain the desired catalyst.

[0076] The particle sizes of the microemulsions prepared in step (1) and step (4) are both 400 nm as determined by dynamic light scattering. Figure 1 is the particle size distribution diagram of the iron microemulsion prepared in step (1). Figure 1 It can be seen that the particle size of the iron microemulsion is mostly within a narrow range of 390 to 410 nm, indicating that the particle size distribution of the microemulsion has reached an ideal level, which is beneficial to the loading of the active components.

[0077] According to the atomic absorption spectrometry, based on the mass of the carrier as 100%, the Pd content of the catalyst is 0.015%, the Ni content is 1.0%, and the Fe content is 0.5%. The Pd content of the solution method is 0.01%, and the Pd content of the emulsion method is 0.005%.

[0078] Before use, the catalyst was placed in a fixed bed reaction device and reduced at a constant temperature of 180° C. for 4 hours in an atmosphere of hydrogen / nitrogen (molar ratio)=1:1, with a reduction space velocity of 200 / h.

[0079] Comparative Example 1

[0080] Carrier: Same as Example 1.

[0081] Catalyst preparation: Similar to Example 1, the only difference is that no Fe is loaded in Comparative Example 1. The preparation process of the catalyst in this comparative example is as follows:

[0082] (1) 3.11 g of nickel nitrate was weighed and dissolved in 35 g of deionized water, and then 100 g of the carrier was added to the Ni salt solution. After the solution was completely absorbed, the catalyst was aged for 4 hours, dried at 120° C., and calcined at 400° C. for 6 hours to obtain a semi-finished catalyst A1;

[0083] (2) Weigh 16.67 mg of palladium chloride and dissolve it in 35 g of deionized water, adjust the pH to 1.5, then add the semi-finished catalyst A1 into the Pd salt solution, age for 10 hours, dry at 120° C., and calcine at 400° C. for 4 hours to obtain the semi-finished catalyst B1;

[0084] (3) Weigh 8.33 mg of palladium chloride and dissolve it in 30 ml of deionized water. Add 14 g of cyclohexane, 3.08 g of Triton X-100, and 2.57 g of n-butanol to 30 ml of deionized water. Impregnate the semi-finished catalyst B1 into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 60° C. for 6 hours and calcine it at 450° C. for 4 hours to obtain the desired catalyst.

[0085] The particle size of the microemulsion prepared in step (3) was 400 nm as determined by dynamic light scattering.

[0086] According to the atomic absorption spectrometry, based on the mass of the carrier as 100%, the Pd content of the catalyst is 0.015%, and the Ni content is 1.0%. The Pd content of the solution method is 0.01%, and the Pd content of the emulsion method is 0.005%.

[0087] Before use, the catalyst was placed in a fixed bed reaction device and reduced at a constant temperature of 180° C. for 4 hours in an atmosphere of hydrogen / nitrogen (molar ratio)=1:1, with a reduction space velocity of 200 / h.

[0088] Experimental Example 1

[0089] The composition of the hydrogenation material is shown in Table 3 below.

[0090] Table 3

[0091]

[0092] Evaluation process conditions: space velocity 6000 / h, reactor inlet temperature: 130°C, single-stage isothermal reaction process. The evaluation results are shown in Table 4.

[0093] Table 4 Evaluation results

[0094]

[0095] From the results of Example 1 and Comparative Example 1, when the inlet temperature of Example 1 is 130°C, the isothermal single-stage reactor can completely remove acetylene. And the selectivity reaches 78.54%. After 1500 hours, the reaction results change very little; while the initial acetylene conversion rate in the comparative example is only 23.14%. Although the change range is also small after 1500 hours, the acetylene conversion efficiency of Comparative Example 1 is significantly lower than that of Example 1. The reason is that there is no Fe loaded in the comparative example, and the active center aggregates formed by a small amount of Pd have a spatial scale smaller than the optimal scale, which makes the catalyst hydrogenation activity insufficient.

[0096] Example 2

[0097] Carrier: Weigh a commercially available bimodal pore distribution spherical carrier with an alumina content of 90%, a titanium oxide content of 10%, and a diameter of 4 mm. After calcination at 1310°C, the pore size distribution ranges are 55-80 nm and 500-800 nm, respectively, the water absorption rate is 35%, and the specific surface area is 3.1 m 2 / g, weigh 100g of the carrier.

[0098] Catalyst preparation:

[0099] (1) Weigh 1.55 g of nickel nitrate, dissolve it in 30 ml of deionized water, add 6.67 g of n-hexane, 0.67 g of CTAB, and 0.47 g of n-pentanol, stir well to form a microemulsion, impregnate 100 g of the calcined carrier into the prepared microemulsion, wait for the emulsion to be completely absorbed, dry at 100°C, and calcine at 500°C for 5 h to obtain a semi-finished catalyst D.

[0100] (2) Weigh 2.17 g of ferric nitrate and dissolve it in 35 g of deionized water, add the semi-finished catalyst D to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 4 hours, dry it at 100° C., and calcine it at 250° C. for 6 hours to obtain the semi-finished catalyst E;

[0101] (3) Weigh 15.15 mg of palladium nitrate and dissolve it in 45 g of deionized water, adjust the pH to 1.7, then add the semi-finished catalyst E to the Pd salt solution, age for 10 hours, dry at 120° C., and calcine at 450° C. for 4 hours to obtain the semi-finished catalyst F;

[0102] (4) Weigh 3.33 mg of palladium chloride and dissolve it in 30 ml of deionized water. Add 6.67 g of n-hexane, 0.67 g of CTAB, and 0.47 g of n-pentanol, and stir well to form a microemulsion. Then, impregnate the semi-finished catalyst F into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 100° C., and calcine it at 550° C. for 4 hours to obtain the desired catalyst.

[0103] The particle size of the microemulsion prepared in steps (1) and (4) was 800 nm as determined by dynamic light scattering.

[0104] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.009%, the Ni content was 0.5%, and the Fe content was 0.5%, with the carrier as 100%. The Pd content of the solution method was 0.007%, and the Pd content of the emulsion method was 0.002%.

[0105] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 190°C for 12 hours, with a reduction space velocity of 150 / h.

[0106] Comparative Example 2

[0107] Carrier: Same as Example 2.

[0108] Catalyst preparation: Similar to Example 2, except that the solution method was not used to load Pd in ​​Comparative Example 2. Catalyst preparation:

[0109] Catalyst preparation:

[0110] (1) Weigh 1.55 g of nickel nitrate, dissolve it in 30 ml of deionized water, add 6.67 g of n-hexane, 0.67 g of CTAB, and 0.47 g of n-pentanol, stir well to form a microemulsion, impregnate 100 g of the calcined carrier into the prepared microemulsion, wait for the emulsion to be completely absorbed, dry at 100° C., and calcine at 500° C. for 5 h to obtain the semi-finished catalyst D1.

[0111] (2) Weigh 2.17 g of ferric nitrate and dissolve it in 35 g of deionized water, add the semi-finished catalyst D1 to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 4 hours, dry it at 100° C., and calcine it at 250° C. for 6 hours to obtain the semi-finished catalyst E1;

[0112] (3) Weigh 3.33 mg of palladium chloride and dissolve it in 30 ml of deionized water. Add 6.67 g of n-hexane, 0.67 g of CTAB, and 0.47 g of n-pentanol. Stir well to form a microemulsion. Impregnate the semi-finished catalyst E1 into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 100° C. and calcine it at 550° C. for 4 hours to obtain the desired catalyst.

[0113] The particle size of the microemulsion prepared in steps (1) and (3) was 800 nm as measured by dynamic light scattering.

[0114] The prepared catalyst was measured by atomic absorption spectrometry, and based on the carrier as 100%, the Pd content of the catalyst was 0.002%, the Ni content of the catalyst was 0.5%, and the Fe content of the catalyst was 0.5%.

[0115] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 190°C for 12 hours, with a reduction space velocity of 150 / h.

[0116] Experimental Example 2

[0117] The composition of the hydrogenation material is shown in Table 5 below.

[0118] Table 5

[0119]

[0120] Evaluation process conditions: 2-stage adiabatic reactor, first stage inlet temperature 95°C, second stage reactor inlet temperature 120°C, space velocity 8000 / h. Evaluation results are shown in Table 6

[0121] Table 6 Evaluation results

[0122]

[0123]

[0124] From the evaluation results in the above table, it can be seen that the acetylene at the outlet of the second stage in Example 2 has been completely converted, and the ethylene selectivity has decreased slightly after 2000 hours compared with the initial period; in Comparative Example 2, the acetylene conversion rate, ethylene and propylene selectivities have decreased slightly after 2000 hours, indicating that the catalyst performance is well maintained in the hydrogenation method, especially the butadiene content in the material reaches 0.15%, which is a relatively high amount.

[0125] The acetylene conversion rate in Comparative Example 2 is very low, indicating that the active component Fe alone has insufficient ability to adsorb and activate hydrogen, resulting in insufficient hydrogenation activity.

[0126] Example 3

[0127] Catalyst preparation:

[0128] The commercially available bimodal pore distribution spherical alumina carrier has a diameter of 4 mm, 80% alumina and 20% magnesia. After calcination at 1250°C, the pore size distribution ranges are 30-55 nm and 310-460 nm, respectively, the water absorption rate is 50%, and the specific surface area is 15 m 2 / g, weigh 100g of the carrier.

[0129] Catalyst preparation:

[0130] (1) Weigh 2.49 g of nickel nitrate and dissolve it in 50 ml of deionized water. Add 20 g of n-hexane, 8.0 g of CTAB, and 8.0 g of n-pentanol, and stir thoroughly to form a microemulsion. Weigh 100 g of the carrier and impregnate it into the prepared microemulsion. After the emulsion is completely absorbed, calcine at 400° C. for 7 h to obtain a semi-finished catalyst H.

[0131] (2) Weigh 6.52 g of ferric nitrate and dissolve it in 50 g of deionized water, then add the semi-finished catalyst H to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 6 hours, dry it at 120° C., and calcine it at 400° C. for 6 hours to obtain a semi-finished catalyst J;

[0132] (3) Weigh 8.66 mg of palladium nitrate and dissolve it in 50 ml of deionized water, add 20 g of n-hexane, 8.0 g of CTAB, and 8.0 g of n-pentanol, stir well to form a microemulsion, and immerse the semi-finished catalyst J in the prepared microemulsion. After the emulsion is completely absorbed, dry it at 60° C., and calcine it at 550° C. for 6 hours to obtain the semi-finished catalyst K;

[0133] (4) 16.67 mg of palladium chloride was weighed and dissolved in 51 g of deionized water, and the pH was adjusted to 2.0. The semi-finished catalyst K was then added to the Pd salt solution, aged for 10 hours, dried at 120° C., and calcined at 400° C. for 4 hours to obtain the desired catalyst.

[0134] The particle size of the microemulsion prepared in steps (1) and (3) was 80 nm as determined by dynamic light scattering.

[0135] The prepared catalyst was measured by atomic absorption spectrometry. Calculated based on the carrier as 100%, the Pd content of the catalyst was 0.014%, the Ni content was 0.8%, and the Fe content was 1.5%. The Pd content loaded by the solution method was 0.010%, and the Pd content loaded by the emulsion method was 0.004%.

[0136] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 210°C for 12 hours, with a reduction space velocity of 350 / h.

[0137] Comparative Example 3

[0138] Carrier: Same as Example 3.

[0139] Catalyst preparation: Similar to Example 3, except that no Ni is loaded in Comparative Example 3.

[0140] Catalyst preparation:

[0141] (1) Weigh 6.52 g of ferric nitrate and dissolve it in 50 g of deionized water, then add 100 g of the calcined carrier into the prepared Fe salt solution, and after the solution is completely absorbed, age it for 6 hours, dry it at 120° C., and calcine it at 400° C. for 6 hours to obtain a semi-finished catalyst J1;

[0142] (2) 8.66 mg of palladium nitrate was weighed and dissolved in 50 ml of deionized water, 20 g of n-hexane, 8.0 g of CTAB, and 8.0 g of n-pentanol were added, and the mixture was stirred thoroughly to form a microemulsion. The semi-finished catalyst J1 was impregnated into the prepared microemulsion, and after the microemulsion was completely absorbed, the mixture was dried at 60° C. and calcined at 550° C. for 6 hours to obtain the semi-finished catalyst K1;

[0143] (3) Weigh 16.67 mg of palladium chloride and dissolve it in 51 g of deionized water, adjust the pH to 2.0, then add the semi-finished catalyst K1 to the Pd salt solution, age it for 10 hours, dry it at 120°C, and calcine it at 400°C for 4 hours to obtain the desired catalyst.

[0144] The particle size of the microemulsion prepared in step (2) was 80 nm as determined by dynamic light scattering.

[0145] The prepared catalyst was measured by atomic absorption spectrometry. Calculated based on the carrier as 100%, the Pd content of the catalyst was 0.014%, and the Fe content was 1.5%. The Pd content of the catalyst loaded by the solution method was 0.010%, and the Pd content of the catalyst loaded by the emulsion method was 0.004%.

[0146] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 210°C for 12 hours, with a reduction space velocity of 350 / h.

[0147] Experimental Example 3

[0148] The composition of the raw materials evaluated is shown in Table 7.

[0149] Table 7 Hydrogenation material composition

[0150]

[0151] Evaluation of process conditions:

[0152] There are three-stage adiabatic reactors, with the inlet temperature of the first reactor at 90°C, the inlet temperature of the second reactor at 110°C, the inlet temperature of the third reactor at 115°C, and the space velocity at 15000 / h.

[0153] Table 8 Test results

[0154]

[0155] As can be seen from the results of Table 8, in Example 3, the second section can still completely convert acetylene after 1500 hours, and the comparative example can completely convert acetylene in the second section reactor in the initial stage, but the comparative example second section acetylene conversion rate is only 98.52% after 1500 hours, and the third section can completely convert acetylene, and the acetylene conversion rate of one section has dropped by nearly 10 percentage points, indicating that the catalyst coking is more serious. From the material composition, its butadiene content is 0.14%, which should be a higher content of butadiene, causing the coking of the catalyst.

[0156] Under the same material composition, the acetylene and PDMA conversions and ethylene propylene selectivity of the three-stage reactor in the embodiment only decreased slightly, indicating that the catalyst coking was very little.

[0157] The reason for the difference between the two is that the catalyst in the comparative example does not load Ni, and the catalyst does not have the function of saturated hydrogenation of butadiene or butadiene polymers. These heavy fractions can continue to polymerize and eventually form coke, which reduces the performance of the catalyst.

[0158] Example 4

[0159] Carrier: A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3 mm was used. After calcination at 1330°C, the bimodal pore size distribution range was 50-70 nm and 430-720 nm, the water absorption rate was 38%, and the specific surface area was 5 m 2 Weigh 100 g of the carrier.

[0160] Catalyst preparation:

[0161] (1) 5.52 g of nickel chloride was dissolved in 35 ml of deionized water, and 8.75 g of n-hexane, 1.4 g of Triton X-100, and 1.08 g of n-octanol were added and stirred thoroughly to form a microemulsion. 100 g of the carrier was impregnated into the prepared microemulsion. After the emulsion was completely absorbed, it was dried at 120° C. for 6 hours and calcined at 550° C. for 3 hours to obtain a semi-finished catalyst M.

[0162] (2) Weigh 3.49 g of ferric chloride and dissolve it in 38 g of deionized water, then add the semi-finished catalyst M to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 1 hour, dry it at 100° C., and calcine it at 350° C. for 8 hours to obtain the semi-finished catalyst N;

[0163] (3) Weigh 12.5 mg of palladium chloride and dissolve it in 38 g of deionized water, adjust the pH to 2.5, then add the semi-finished catalyst N to the prepared Pd salt solution, age it for 12 hours, dry it at 100° C., and calcine it at 450° C. for 6 hours to obtain the semi-finished catalyst O;

[0164] (4) Weigh 27.17 mg of palladium nitrate and dissolve it in 40 ml of deionized water. Add 8.75 g of n-hexane, 1.4 g of Triton X-100, and 1.08 g of n-octanol. Stir thoroughly to form a microemulsion. Impregnate the semi-finished catalyst O into the prepared microemulsion. After immersion for 4 hours, filter out the remaining liquid; wash with deionized water until neutral, dry at 120° C. for 6 hours, and calcine at 450° C. for 6 hours to obtain the desired catalyst.

[0165] The particle size of the microemulsion prepared in steps (1) and (4) was 600 nm as determined by dynamic light scattering.

[0166] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.020%, the Ni content was 2.5%, and the Fe content was 1.2%, with the carrier as 100%. The Pd content of the solution method was 0.0075%, and the Pd content of the emulsion method was 0.0125%.

[0167] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 200°C for 12 hours, with a reduction space velocity of 200 / h.

[0168] Comparative Example 4

[0169] Carrier: Same as Example 4.

[0170] Catalyst: Similar to Example 4, except that the emulsion method for loading Pd is omitted.

[0171] Catalyst preparation:

[0172] (1) 5.52 g of nickel chloride was dissolved in 35 ml of deionized water, and 8.75 g of n-hexane, 1.4 g of Triton X-100, and 1.08 of n-octanol were added and stirred thoroughly to form a microemulsion. 100 g of the carrier was impregnated into the prepared microemulsion. After the emulsion was completely absorbed, it was dried at 120° C. for 6 hours and calcined at 550° C. for 3 hours to obtain the semi-finished catalyst M1.

[0173] (2) Weigh 3.49 g of ferric chloride and dissolve it in 38 g of deionized water, then add the semi-finished catalyst M1 to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 1 hour, dry it at 100° C., and calcine it at 350° C. for 8 hours to obtain the semi-finished catalyst N1;

[0174] (3) Weigh 12.5 mg of palladium chloride and dissolve it in 38 g of deionized water. Adjust the pH to 2.5. Then add the semi-finished catalyst N1 to the prepared Pd salt solution, age it for 12 hours, dry it at 100° C., and calcine it at 450° C. for 6 hours to obtain the desired catalyst.

[0175] The particle size of the microemulsion prepared in step (1) was 600 nm as determined by dynamic light scattering.

[0176] The prepared catalyst was measured by atomic absorption spectrometry. Based on the support being 100%, the Pd content of the catalyst was 0.0075%, the Ni content was 2.5%, and the Fe content was 1.2%.

[0177] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 200°C for 12 hours, with a reduction space velocity of 200 / h.

[0178] Experimental Example 4

[0179] The composition of the evaluated materials is shown in Table 9.

[0180] Table 9 Hydrogenation material composition

[0181]

[0182] Evaluation process conditions: single-stage isothermal reactor, reactor inlet temperature 110°C, space velocity 10000 / h. Specific evaluation results are shown in Table 10.

[0183] Table 10 Evaluation results

[0184] Example 4 Comparative Example 4 Initial acetylene conversion; % 100 100 Initial PDMA conversion, % 64.25 64.34 Initial ethylene selectivity, % 78.64 78.49 Initial propylene selectivity, % 93.14 93.27 Acetylene conversion rate at 2000 hours, % 100 97.31 2000 hours PDMA conversion rate, % 63.87 58.23 2000 hours ethylene selectivity, % 76.53 68.29 2000 hours propylene selectivity, % 92.67 89.71 Catalyst weight gain after 2000 hours, % 3.27 8.92

[0185] From the results of Table 10, in the initial stage of the reaction, the acetylene conversion of Example 4 and Comparative Example 4 both reached 100%, and there was almost no difference in their ethylene selectivity, PDMA conversion rate and propylene selectivity. However, after 2000 hours, the acetylene conversion rate of Example 4 was still 100%, while the acetylene conversion rate of Comparative Example 4 was only 97.31%, and the acetylene at the reactor outlet exceeded the standard by a large margin, and the reaction result was already unqualified. In addition, the PDMA conversion rate, ethylene selectivity and propylene selectivity in the comparative example all decreased significantly. From the perspective of catalyst weight gain, the catalyst weight gain in Comparative Example 4 exceeded that of the catalyst in Example 4 by more than 1 times. The results show that the catalyst coking was serious because Pd was not loaded by the emulsion method. The reason is that the catalyst reduction temperature is 200°C, and when there is no Pd on the NiO surface, the reduction temperature generally requires 450°C. At the reduction temperature given in this experiment, NiO was not reduced and did not have the function of hydrogenating butadiene, etc., resulting in serious coking of the catalyst in Comparative Example 4 and a significant decrease in catalyst performance.

[0186] Example 5

[0187] Carrier: A commercially available bimodal pore distribution spherical carrier with a diameter of 3.5 mm and a composition of 95% alumina and 5% magnesium oxide was used. After calcination at 1310°C, the specific surface area was 12 m 2 / g, water absorption rate 48%, small pore diameter 40-60nm, large pore diameter 360-500nm, weigh 100g of the carrier.

[0188] Catalyst preparation:

[0189] (1) Weigh 2.65 g of nickel chloride, dissolve it in 45 ml of deionized water, add 15.51 g of cyclohexane, 5.12 g of Triton X-10, and 4.66 g of n-butanol, stir thoroughly to form a microemulsion, and impregnate 100 g of the carrier into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 120° C. for 6 hours, and calcine it at 450° C. for 5 hours to obtain a semi-finished catalyst P.

[0190] (2) Weigh 3.91 g of ferric nitrate and dissolve it in 48 g of deionized water, then add the semi-finished catalyst P to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 4 hours, dry it at 110° C., and calcine it at 350° C. for 2 hours to obtain the semi-finished catalyst Q;

[0191] (3) Weigh 5.67 mg of palladium chloride and dissolve it in 48 g of deionized water, adjust the pH to 1.9, then add the semi-finished catalyst Q to the prepared Pd salt solution, and after the solution is completely absorbed, age it for 12 hours, dry it at 100° C., and calcine it at 400° C. for 8 hours to obtain the semi-finished catalyst R;

[0192] (4) Weigh 6 mg of palladium chloride and dissolve it in 45 ml of deionized water. Add 15.51 g of cyclohexane, 5.12 g of Triton X-10, and 4.66 g of n-butanol, and stir thoroughly to form a microemulsion. Impregnate the semi-finished catalyst R into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 120° C. for 6 hours and calcine it at 480° C. for 6 hours to obtain the desired catalyst.

[0193] The particle size of the microemulsion prepared in steps (1) and (4) was 200 nm as determined by dynamic light scattering.

[0194] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.007%, the Ni content was 1.2%, and the Fe content was 0.9%, with the carrier being 100%. The Pd content of the solution method was 0.0034%, and the Pd content of the emulsion method was 0.0036%.

[0195] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 190°C for 12 hours, with a reduction space velocity of 150 / h.

[0196] Comparative Example 5

[0197] Carrier: Same as Example 5.

[0198] Catalyst: Same as Example 5.

[0199] The particle size of the microemulsion prepared in steps (1) and (4) was 200 nm as determined by dynamic light scattering.

[0200] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.007%, the Ni content was 1.2%, and the Fe content was 0.9%, with the carrier being 100%. The Pd content of the solution method was 0.0034%, and the Pd content of the emulsion method was 0.0036%.

[0201] Before use, it was placed in a fixed bed reaction device and reduced with a mixed gas with a molar ratio of N2:H2=1:1 at a temperature of 190°C for 12 hours, with a reduction space velocity of 150 / h.

[0202] Experimental Example 5

[0203] The composition of the evaluated materials is shown in Table 11.

[0204] Table 11 Comparative Example Evaluation Results

[0205]

[0206] Evaluation of process conditions

[0207] Example 5: Single-stage adiabatic reactor, reactor inlet temperature 95°C, space velocity 10000 / h,

[0208] Comparative Example 5: Single-stage adiabatic reactor, reactor inlet temperature 85°C, space velocity 10000 / h,

[0209] The evaluation results are shown in Table 12.

[0210] Table 12 Evaluation results

[0211] Example 5 Comparative Example 5 Initial acetylene conversion; % 100 98.64 Initial PDMA conversion, % 54.32 48.69 Acetylene conversion rate in 1000 hours, % 100 98.51 1000 hours PDMA conversion rate, % 53.65 47.85 Catalyst weight gain after 1000 hours, % 2.60 2.14

[0212] As can be seen from Table 12, in Example 5, the single-stage adiabatic reaction can completely convert acetylene, and still maintains a good acetylene removal effect after 1000 hours of operation; the comparative example reactor inlet temperature is 85°C, and acetylene cannot be completely converted. After 1000 hours, the amount of coking of the catalyst in Comparative Example 5 is still lower than that in the embodiment (catalyst weight gain), indicating that it is not the catalyst coking that affects the reaction results, but the insufficient activity of the catalyst in the comparative example. It is inferred that the low reactor inlet temperature leads to the insufficient catalyst activity in the comparative example. That is, the low reactor inlet temperature leads to the low catalyst activity in the comparative example. Compared with the traditional method using Pd as the hydrogenation active component, the hydrogenation method of the present invention has a significantly higher reactor inlet temperature.

[0213] Example 6

[0214] Carrier: A commercially available bimodal pore distribution spherical carrier with a diameter of 4 mm was used. After calcination at 1325°C, the specific surface area was 12 m 2 / g, water absorption rate 48%, small pore diameter 40-65nm, large pore diameter 390-540nm, weigh 100g of the carrier.

[0215] Catalyst preparation:

[0216] (1) Weigh 4.35 g of ferric nitrate and dissolve it in 48 g of deionized water. Then, weigh 100 g of the carrier and add it to the prepared Fe salt solution. After the solution is completely absorbed, age it for 6 hours, dry it at 120° C., and calcine it at 600° C. for 8 hours to obtain a semi-finished catalyst S.

[0217] (2) Weigh 2.21 g of nickel chloride, dissolve it in 40 ml of deionized water, add 15.38 g of n-hexane, 5.69 g of Triton X-10, and 4.07 g of n-octanol, stir well to form a microemulsion, and then immerse the semi-finished catalyst S in the prepared microemulsion. After the emulsion is completely absorbed, dry it at 80° C., and calcine it at 600° C. for 8 h to obtain the semi-finished catalyst T;

[0218] (3) Weigh 21.7 mg of palladium nitrate and dissolve it in 48 g of deionized water, adjust the pH to 2.3, then add the semi-finished catalyst T to the Pd salt solution, age for 10 hours, dry at 120° C., and calcine at 550° C. for 4 hours to obtain a semi-finished catalyst U;

[0219] (4) Weigh 15.0 mg of palladium nitrate, dissolve it in 40 ml of deionized water, add 15.38 g of n-hexane, 5.69 g of Triton X-10, and 4.07 g of n-pentanol, stir well to form a microemulsion, and impregnate the semi-finished catalyst U into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 80°C, and calcine it at 400°C for 4 hours to obtain the desired catalyst.

[0220] The particle size of the microemulsion prepared in steps (2) and (4) was 100 nm as determined by dynamic light scattering.

[0221] The prepared catalyst was measured by atomic absorption spectrometry, and calculated based on the carrier as 100%, in Example 6, the Pd content was 0.017%, the Ni content was 1.0%, and the Fe content was 1.0%. The Pd content loaded by the solution method was 0.010%, and the Pd content loaded by the emulsion method was 0.007%.

[0222] Before use, it was placed in a fixed bed reaction device and reduced with pure hydrogen at 210°C for 8 hours with a reduction space velocity of 150 / h.

[0223] Comparative Example 6

[0224] Carrier: same as Example 6. Catalyst preparation: same as Example 6.

[0225] The particle size of the microemulsion prepared in steps (2) and (4) was 100 nm as determined by dynamic light scattering.

[0226] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.017%, the Ni content was 1.0%, and the Fe content was 1.0%, with the carrier as 100%. The Pd content of the solution method was 0.010%, and the Pd content of the emulsion method was 0.007%.

[0227] Before use, it was placed in a fixed bed reactor and reduced with pure hydrogen at 210°C for 8 hours with a reduction space velocity of 150 / h.

[0228] Experimental Example 6

[0229] The composition of hydrogenation materials is shown in Table 13.

[0230] Table 13 Hydrogenation material composition

[0231]

[0232]

[0233] Process conditions:

[0234] Two-stage adiabatic reactor, space velocity 12000 / h.

[0235] Temperature: before 1500 hours, the inlet temperature of the first reactor was 95°C, and the inlet temperature of the second reactor was 110°C; after 1500 hours, the inlet temperature of the first reactor was 95°C, and the inlet temperature of the second reactor was 125°C.

[0236] The evaluation results are shown in Table 14.

[0237] Table 14 Evaluation results

[0238]

[0239] From the results in Table 14, the conversion rate of the first stage of Example 6 at the beginning of the reaction is 68.61%, and the conversion rate of the first stage of Comparative Example 6 is 46.28%, which is more than 20 percentage points lower than that of the embodiment; the second stage of Example 6 completely converts acetylene, while the second stage reactor of Comparative Example 6 does not completely convert acetylene. Since the catalyst is the same and the reaction process conditions are also the same, the difference in the reaction results should be caused by the difference in materials. As can be seen from Table 13, the CO content in the reaction material of Comparative Example 6 is 1 times higher than that of Example 6. Although Fe is less sensitive to CO than Pd, excessive CO will still seriously inhibit the hydrogenation activity of Fe, or high content of CO will intensify the competitive adsorption of hydrogen on Pd atoms, resulting in the inhibition of the transfer of hydrogen to the active center of Fe, resulting in the inability to completely convert acetylene in the second stage reactor of the comparative example; after 1500 hours, the inlet temperature of the second stage reactor is increased by 10°C, and the ethylene selectivity of the second stage of the embodiment at 2000 hours is reduced by more than 6 percentage points compared with 1000 hours, while it is only reduced by 2 percentage points in Comparative Example 6, indicating that high CO content is still beneficial to improving selectivity. However, the CO content was too high. Even if the second stage inlet temperature was increased by 15°C, comparative example 6 still did not completely convert acetylene. From the weight gain of the catalyst after 2000 hours, the weight gain of the comparative example and the example catalyst was not significant, which did not seriously affect the catalyst performance. Therefore, it can be concluded that the reason why the second stage of the comparative example did not completely convert acetylene was that the CO content in the material was too high.

[0240] Example 7

[0241] Carrier: A commercially available spherical alumina carrier with a diameter of 2 mm was used. After being calcined at 1300°C for 4 hours, the water absorption rate was 44%, the small pore diameter was 40-65 nm, the large pore diameter was 390-540 nm, and the specific surface area was 9 m 2 Weigh 100 g of the carrier.

[0242] Catalyst preparation:

[0243] (1) Weigh 6.22 g of nickel nitrate, dissolve it in 40 ml of deionized water, add 11.42 g of cyclohexane, 3.08 g of Triton X-10, and 2.8 g of n-butanol, stir thoroughly to form a microemulsion, impregnate 100 g of the carrier into the prepared microemulsion, dry at 120° C. for 6 hours after the emulsion is completely absorbed, and calcine at 550° C. for 5 hours to obtain a semi-finished catalyst P.

[0244] (2) Weigh 6.52 g of ferric nitrate and dissolve it in 48 g of deionized water, then add the semi-finished catalyst P to the prepared Fe salt solution, and after the solution is completely absorbed, age it for 4 hours, dry it at 110° C., and calcine it at 280° C. for 4 hours to obtain a semi-finished catalyst Q;

[0245] (3) Weigh 16.67 mg of palladium chloride and dissolve it in 48 g of deionized water, adjust the pH to 1.9, then add the semi-finished catalyst Q to the prepared Pd salt solution, and after the solution is completely absorbed, age it for 12 hours, dry it at 100° C., and calcine it at 520° C. for 8 hours to obtain the semi-finished catalyst R;

[0246] (4) Weigh 16.67 mg of palladium chloride, dissolve it in 40 ml of deionized water, add 11.42 g of cyclohexane, 3.08 g of Triton X-10, and 2.8 g of n-butanol, stir thoroughly to form a microemulsion, and impregnate the semi-finished catalyst R into the prepared microemulsion. After the emulsion is completely absorbed, dry it at 120° C. for 6 hours, and calcine it at 500° C. for 6 hours to obtain the desired catalyst.

[0247] The particle size of the microemulsion prepared in steps (1) and (4) was 300 nm as determined by dynamic light scattering.

[0248] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.02%, the Ni content was 2.0%, and the Fe content was 1.5%, with the carrier being 100%. The Pd content of the solution method was 0.010%, and the Pd content of the emulsion method was 0.01%.

[0249] Before use, it was placed in a fixed bed reaction device and reduced with pure hydrogen at 220°C for 8 hours with a reduction space velocity of 150 / h.

[0250] Comparative Example 7

[0251] The carrier and catalyst are the same as those in Example 7.

[0252] The particle size of the microemulsion prepared in steps (1) and (4) was 300 nm as determined by dynamic light scattering.

[0253] The prepared catalyst was measured by atomic absorption spectrometry, and the Pd content was 0.02%, the Ni content was 2.0%, and the Fe content was 1.5%, with the carrier being 100%. The Pd content of the solution method was 0.010%, and the Pd content of the emulsion method was 0.01%.

[0254] Before use, it was placed in a fixed bed reaction device and reduced with pure hydrogen at 220°C for 8 hours with a reduction space velocity of 150 / h.

[0255] Experimental Example 7

[0256] The composition of the evaluated materials is shown in Table 15.

[0257] Table 15 Material composition

[0258]

[0259] Process conditions: The reaction process is a three-stage adiabatic process, with the first stage reactor inlet temperature at 90°C, the second stage inlet temperature at 100°C, and the third stage inlet temperature at 120°C.

[0260] The air velocity of Example 7 is 20000 / h, and the air velocity of Comparative Example 7 is 5000 / h. The specific evaluation results are shown in Table 16.

[0261] Table 16 Evaluation results

[0262]

[0263] As can be seen from Table 16, at the initial stage of the reaction, the acetylene conversion rate of the first stage of the comparative example reached 79.54%, which is very high, but the selectivity is already lower than 70%; the second stage of the comparative example 7 completely converts acetylene, and the selectivity is close to 50%, that is, 50% of the converted acetylene is hydrogenated to ethane, and the hydrogenation tendency of ethylene is already very obvious. After the third stage, there is no inhibition of ethylene hydrogenation by acetylene, and the temperature is high, CO cannot effectively inhibit the hydrogenation of ethylene, resulting in temperature runaway.

[0264] In Example 7, at high CO content, the acetylene conversion rate in the first stage cannot reach 50%, and the selectivity is as high as over 94%. Only in the third stage can acetylene be completely converted, and the selectivity of the third stage is also over 60%. It shows that under high CO and high air velocity conditions, the hydrogenation activity of acetylene is significantly inhibited, but the selectivity is very high. In other words, the air velocity of 5000 / h in the comparative example is lower than the minimum (critical) air velocity at which the reaction can operate stably, the reaction activity is too high and the selectivity is too low, resulting in a temperature runaway. Due to the three-stage temperature runaway in Comparative Example 7, the temperature of the second stage of Example 7 and Comparative Example 7 was reduced to 95°C, and the temperature of the third stage was reduced to 105°C. That is, the reduction reached 15°C, and then the evaluation was carried out. The results are shown in Table 17 below.

[0265] Table 17 Evaluation results of Example 7 and Comparative Example 7 after cooling

[0266]

[0267]

[0268] As can be seen from the data in the above table, after 1500 hours of lowering the temperature, the activity selectivity of the first and second stages of Example 7 slightly decreased; however, the activity selectivity of the first stage of Comparative Example 7 decreased significantly, and the activity of the second stage of Comparative Example 7 also decreased significantly. The reason is that when the air velocity is very low, the activity of the first stage of Comparative Example 7 is too high, and butadiene polymerizes when it is too late to hydrogenate. As can be seen from Table 17, after 1500 hours, the weight of the first stage catalyst of Comparative Example 7 increased by more than 13%, that is, butadiene formed a large amount of coking in the first stage reactor of Comparative Example 7, resulting in a significant decrease in its activity selectivity. Some of the macromolecules formed after the polymerization of these butadienes also entered the second stage reactor, affecting the performance of the catalyst in the second stage reactor. If the operation time is long enough, not only will the activity selectivity of the second stage reactor decrease, but it will also cause the selectivity of the third stage reactor to decrease, and eventually lead to acetylene leakage.

[0269] Therefore, the space velocity index is a key index for the hydrogenation reaction of C1-C3 fractions.

[0270] Compared with the traditional hydrogenation method of C1-C3 fraction, the minimum air velocity in the hydrogenation method of the present invention is significantly lower, which is of great significance for ensuring the safety of hydrogenation reaction. The selective hydrogenation of C1-C3 fraction of industrial equipment generally operates at a lower air velocity in the early stage of operation to avoid the waste of burning materials due to the large air velocity; if the critical (minimum) air velocity value of the reaction is high, it is easy to make the actual air velocity lower than the critical air velocity, so that a temperature runaway accident will occur, which will not only cause great economic losses, but also cause serious safety accidents such as explosion of the equipment.

[0271] Example 8 and Comparative Example 8

[0272] The catalysts used in Example 8 and Comparative Example 8 are the same as those used in Example 7.

[0273] Experimental Example 8

[0274] Evaluation material composition, see Table 18

[0275] Table 18 Evaluation material composition of Example 8 and Comparative Example 8

[0276]

[0277]

[0278] Process conditions: The reaction process is a three-stage adiabatic process, with the first stage reactor inlet temperature at 90°C, the second stage inlet temperature at 100°C, and the third stage inlet temperature at 105°C.

[0279] Preparation of hydrogenation materials: The carbon dioxide fraction, carbon three fraction, methane, hydrogen and CO from the industrial device pipeline are prepared online in proportion. Among them, CO is added alone, and the rate of change of its content is: decreasing from 0.015% (v) to 0.03% (v) within 15 minutes.

[0280] Sampling and analysis method: Analyze once before adjusting the CO content, and once after adjusting the CO content. The sampling interval is the adjustment time of the CO content.

[0281] The space velocity of Example 8 is 15000 / h, and the space velocity of Comparative Example 8 is 5500 / h.

[0282] The evaluation results are shown in Table 19.

[0283] Table 19 Evaluation results of Example 8 and Comparative Example 8

[0284]

[0285] During the evaluation process, the materials used in Example 8 and Comparative Example 8 were the same materials after unified preparation.

[0286] After being measured by different flow meters, it enters different reactors, and the space velocities of the reactors are different.

[0287] As can be seen from Table 19, when the CO content is 0.15%, the acetylene conversion rate of the first stage reactor of Comparative Example 8 is significantly higher than that of the first stage reactor of the embodiment, and the acetylene conversion rate of the second stage of the comparative example has reached 100%. However, there is no temperature runaway in the third stage. When the CO content is reduced, the acetylene conversion rate of the first stage of Example 8 reaches more than 90%, the acetylene conversion rate of the second stage reaches 100%, and there is no temperature runaway in the third stage. After reducing the CO content, the ethylene selectivity of each stage in the embodiment is reduced by about 10 percentage points, but the selectivity of the third stage is still above 50%, indicating that the large fluctuation of CO will not lead to a large change in the selectivity of the hydrogenation reaction.

[0288] In Comparative Example 8, when the CO content changes significantly, the first reactor can completely convert acetylene, the selectivity is less than 55%, and the second and third stages have temperature runaway. This indicates that at low space velocity or after the space velocity is lower than the critical value, when the CO content decreases significantly, the reactor temperature runaway will inevitably occur. This indicates that for this hydrogenation method, the space velocity is still a key parameter.

[0289] For the pre-hydrogenation process, the dramatic change of CO content in the hydrogenation material mainly occurs in the following situations: 1) new cracking furnace is put into operation; 2) cracking furnace is decoked online; cracking furnace is replaced with raw materials, etc. However, in a short period of time, such as CO is reduced from 0.15% (V) to 0.03% (V) or increased from 0.03% (V) to 0.15% (V) within 15 minutes, it is still a relatively rare dramatic change. This Example 8 and Comparative Example 8 show that under normal space velocity, the hydrogenation method of the present invention has good ability to resist CO fluctuations.

[0290] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for selective hydrogenation of a C1-C3 fraction, wherein the C1-C3 fraction comes from the top of a depropanizer of an ethylene plant, and the C1-C3 fraction is subjected to a selective hydrogenation reaction with hydrogen in a fixed bed reactor containing a catalyst, characterized in that: The process conditions of the selective hydrogenation reaction are: the reactor inlet temperature is 90-130°C, the gas volume space velocity is 6000-20000h -1 ; The volume content of CO in the C1-C3 fraction is 0.03% to 0.2%; The catalyst used in the selective hydrogenation reaction is alumina or mainly alumina, with a specific surface area of ​​3 to 15 m 2 / g, having a bimodal pore size distribution characteristic, with a small pore size of 30-80nm and a large pore size of 300-800nm; the active components include Pd, Ni and Fe, Pd is loaded by both microemulsion method and solution method, Ni is loaded by microemulsion method, and Fe is loaded by solution method; and the solution method loads Pd after the solution method loads Fe, and the microemulsion method loads Pd after the microemulsion method loads Ni; the microemulsion method loads Pd and Ni in the large pores, and the solution method loads Fe and Pd in ​​the small pores; Taking the mass of the carrier as 100%, the Ni content is 0.5% to 2.5%, the Fe content is 0.5% to 1.5%, and the Pd content is 0.007% to 0.020%; the Pd content loaded by the microemulsion method is 0.002 to 0.007 of the Ni content; The catalyst is reduced at 180-230°C before being put into the selective hydrogenation reaction.

2. The method for selective hydrogenation of C1-C3 fractions according to claim 1, characterized in that: Taking the total volume of the C1-C3 fraction as 100%, the H2 content is 10%-30%, the C2H4 content is 25%-40%, the C2H2 content is 0.4%-0.9%, the C3H6 content is 5%-11%, the PDMA content is 0.2%-1.2%, the CO content is 0.03%-0.2%, the butadiene content is ≤0.2%, and the remainder is methane, ethane and propane.

3. The method for selective hydrogenation of C1-C3 fractions according to claim 1, characterized in that: The selective hydrogenation reaction is single-stage hydrogenation, two-stage hydrogenation or three-stage hydrogenation.

4. The method for selective hydrogenation of C1-C3 fractions according to claim 1, characterized in that: The process of loading Ni or Pd by microemulsion method comprises the following steps: dissolving Ni precursor salt or Pd precursor salt in water to obtain an aqueous phase, then adding an oil phase, a surfactant and a co-surfactant to the aqueous phase, and stirring to form a microemulsion.

5. The method for selective hydrogenation of C1-C3 fractions according to claim 4, characterized in that: The mass ratio of the water phase to the oil phase is 2.0-4.5, the mass ratio of the surfactant to the oil phase is 0.10-0.4, and the mass ratio of the surfactant to the co-surfactant is 1.0-1.

5.

6. The method for selective hydrogenation of C1-C3 fractions according to claim 4, characterized in that: The oil phase is C6-C8 saturated alkane or cycloalkane, preferably cyclohexane or n-hexane.

7. The method for selective hydrogenation of C1-C3 fractions according to claim 4, characterized in that: The surfactant is an ionic surfactant and / or a nonionic surfactant, preferably a nonionic surfactant, more preferably polyethylene glycol octylphenyl ether or hexadecyltrimethylammonium bromide.

8. The method for selective hydrogenation of C1-C3 fractions according to claim 4, characterized in that: The co-surfactant is an organic alcohol; preferably C4-C6 alcohols, more preferably n-butanol and / or n-pentanol.

9. The method for selective hydrogenation of C1-C3 fractions according to claim 1, characterized in that: The sequence of loading the active component into the carrier comprises the following steps: Microemulsion loading of Ni, solution method loading of Fe, solution method loading of Pd, microemulsion method loading of Pd; or Microemulsion loading of Ni, solution method loading of Fe, microemulsion method loading of Pd, solution method loading of Pd; or Solution method loading Fe, microemulsion loading Ni, solution method loading Pd, microemulsion method loading Pd; or Microemulsion loading of Ni, microemulsion method loading of Pd, solution method loading of Fe, solution method loading of Pd.

10. The method for selective hydrogenation of C1-C3 fractions according to claim 1, characterized in that: Before the catalyst is put into the selective hydrogenation reaction, the reducing atmosphere is pure hydrogen or a mixture of hydrogen and nitrogen.

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