Non-selective superposition method of C4 olefins

Abstract

This invention relates to the field of catalytic chelation and discloses a non-selective chelation method for C4 olefins. The method includes: sequentially subjecting C4 olefins to a first chelation reaction and a second chelation reaction in the presence of a modified amorphous aluminosilicate catalyst; wherein the modified amorphous aluminosilicate catalyst is composed of an amorphous aluminosilicate catalyst and a copper-zinc component supported thereon, the silica-alumina ratio of the amorphous aluminosilicate catalyst is 1.5-3, and the copper-zinc component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, z is the number of oxygen atoms satisfying the valence of each metal element, the content of the copper-zinc component is 1-10% by mass of the amorphous silica-alumina catalyst, and in the modified amorphous silica-alumina catalyst, 0-valent copper and +1-valent copper account for more than 50% of the total copper content. The non-selective superposition method of the present invention has a high C4 olefin conversion rate.

Description

Technical Field

[0001] This invention relates to the field of catalytic chelation, and more specifically to a non-selective chelation method for C4 olefins. Background Technology

[0002] my country has abundant C4 hydrocarbon (liquefied petroleum gas) resources. In 2016, the country's crude oil processing volume reached 541 million tons, with refineries producing approximately 17 million tons of C4 hydrocarbons as a byproduct. Cracked C4 hydrocarbons account for about one-quarter of total ethylene production, producing 4.25 million tons of C4 hydrocarbons as a byproduct. Currently, my country's total C4 hydrocarbon reserves have reached 25 million tons. C4 hydrocarbons have a wide range of applications. They can be used as fuels through aromatization, alkylation, and isomerization, and can also be used to produce various chemical products such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl ethyl ketone (MEK), and sec-butyl acetate. MTBE, as a significant pathway for isobutylene consumption, plays a crucial role in the downstream utilization of butene-1 and butene-2. 62% of MTBE production capacity is concentrated in Asia.

[0003] The latest Chinese standard for ethanol gasoline prohibits the artificial addition of oxygen-containing organic compounds, meaning that etherified components such as MTBE can no longer be used as gasoline blending components. Therefore, with the ban on MTBE, there is an urgent need to find new chemical pathways for liquefied petroleum gas (LPG), and the improvement and optimization of C4 hydrocarbon conversion and utilization technologies are urgently needed.

[0004] Fully alkylation reaction (non-selective alkylation reaction) involves the reaction between isobutylene, n-butene, cis-2-butene, and trans-2-butene to produce polyolefins. Polyolefins produced by alkylation reaction have a high degree of branching and are characterized by high research octane number, low vapor pressure, no sulfur, and no aromatics, making them ideal additives for clean gasoline.

[0005] Currently, there are three main industrially mature processes globally for producing petroleum products that meet international additive standards from olefin full smothermal synthesis: the SPAC process from UOP (U.S.), the non-selective MOGD smothermal synthesis process from the former Mobil (U.S.), and the Polynaphtha process from Axens (France). Among these, UOP's SPAC process is characterized by its simple process flow, readily available and inexpensive solid phosphoric acid catalysts, and long lifespan, making it one of the most widely used full smothermal processes in the world. However, with increasingly stringent environmental regulations, the drawbacks of solid phosphoric acid catalysts—such as easy sludge formation, non-renewability, and the difficulty of post-treatment due to strong acidity—have become increasingly prominent. Although researchers both domestically and internationally have conducted extensive research on solid phosphoric acid catalysts (CN1997450A, CN100496724C, CN1226095C, etc.), employing various novel phosphoric acid supports such as diatomaceous earth, silica, and activated carbon to continuously extend the catalyst's lifespan and catalytic activity, none of these studies have solved the problems of easy sludge formation and non-renewability of solid phosphoric acid catalysts. Mobil's MOGD process uses ZSM-5 molecular sieve catalysts, offering flexible reaction conditions to meet diverse market demands. However, this gas-solid reaction involves extremely high temperatures, high energy consumption, and difficult plant construction, thus limiting its large-scale adoption. Axens' Polynaphtha process uses a co-precipitation method to prepare silica-alumina catalysts. These catalysts are regenerable, have a long lifespan, and are easy to handle after deactivation. The process is also simple, requiring no modifiers. However, the co-precipitation method produces a low amount of Brønsted acid (B acid) and a low B / L acid ratio, requiring higher reaction temperatures and pressures. This results in significant olefin polymerization, with only about 40% selectivity for C8 olefins, limiting their application to diesel component modifiers. However, due to my country's focus on gasoline development, the market for the resulting blended diesel is limited, hindering large-scale application. Therefore, developing a novel blended gasoline process has become a research hotspot. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem that the total conversion rate of C4 olefins drops significantly to below 70% after a long period of operation (>30 days) in the non-selective fusion reaction of the prior art, and to provide a non-selective fusion method with high C4 olefin conversion rate.

[0007] To achieve the above objectives, the present invention provides a non-selective superposition method for C4 olefins, the method comprising: subjecting C4 olefins to a first superposition reaction and a second superposition reaction in the presence of a modified amorphous silica-alumina catalyst.

[0008] The modified amorphous silica-alumina catalyst comprises an amorphous silica-alumina catalyst and a copper-zinc-aluminum component supported thereon. The silica-alumina ratio of the amorphous silica-alumina catalyst is 1.5-3, preferably 1.8-2.5. The copper-zinc-aluminum component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, and z is the number of oxygen atoms satisfying the oxidation states of each metal element. The content of the copper-zinc-aluminum component is 1-10% by mass of the amorphous silica-alumina catalyst, preferably 3-5% by mass, and in the modified amorphous silica-alumina catalyst, 0-valent copper and +1-valent copper account for more than 50% of the total copper content, preferably more than 70%. The conditions for the first superposition reaction include: reaction temperature 160-200℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 The conditions for the second superposition reaction include: reaction temperature 180-240℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 .

[0009] Preferably, the conditions for the first superposition reaction include: a reaction temperature of 170-190°C, a reaction pressure of 5-6 MPa, and a liquid hourly space velocity of 0.5-1.2 h⁻¹. -1 ; and / or the conditions for the second superposition reaction include: reaction temperature 180-220℃, reaction pressure 5-6MPa, and liquid hourly space velocity 0.5-1.2h. -1 .

[0010] Preferably, the non-selective superposition method further includes a step of regenerating the modified amorphous silica-alumina catalyst, and preferably the regeneration is an online regeneration.

[0011] Preferably, the regeneration conditions include: an oxygen-containing atmosphere, a temperature of 450-600°C, and a time of 4-10 hours.

[0012] Preferably, in the modified amorphous silica-alumina catalyst, 0-valent copper accounts for 30-50% of the total copper content, and +1-valent copper accounts for 30-50% of the total copper content.

[0013] Preferably, the amorphous silica-alumina catalyst has a pore size of 20-50 nm.

[0014] Preferably, the specific surface area of ​​the amorphous silica-alumina catalyst is less than 250 m². 2 / g.

[0015] Preferably, the XRD pattern of the amorphous silica-alumina catalyst has only one diffuse diffraction peak at 25° to 27°.

[0016] Preferably, the modified amorphous silica-alumina catalyst is prepared by the following method:

[0017] (1) The copper-zinc-aluminum components are subjected to hydrogenation pretreatment;

[0018] (2) The amorphous silica-alumina catalyst is mixed with the product obtained in step (1) and subjected to first drying, first calcination and hydrothermal treatment in sequence.

[0019] Preferably, in step (2), the conditions for the first calcination include: an inert atmosphere, a temperature of 400-580°C, and a time of 1-5 hours.

[0020] Preferably, in step (1), the preparation method of the copper-zinc-aluminum component includes: contacting the precipitant with a copper source, a zinc source, and a second aluminum source under pH 5-9 conditions, followed by a second aging, washing, a second drying, and a second calcination to obtain the copper-zinc-aluminum component.

[0021] Preferably, the precipitant is an alkali or an alkaline salt.

[0022] Preferably, in step (1), the hydrogenation pretreatment makes the 0-valent copper and +1-valent copper account for more than 50% of the total copper content in the copper-zinc-aluminum composition, more preferably more than 70%; more preferably, the hydrogenation pretreatment makes the 0-valent copper account for 30-50% of the total copper content and the +1-valent copper account for 30-50% of the total copper content in the copper-zinc-aluminum composition.

[0023] Preferably, in step (1), the conditions for hydrogenation pretreatment include: reduction with hydrogen or hydrogen-containing gas at 150-300°C and 0.1-8MPa for 2-40 hours.

[0024] Preferably, the superposition reaction is carried out in a fixed-bed reactor.

[0025] Preferably, the modified amorphous silica-alumina catalyst has a particle size of 20-40 mesh.

[0026] Preferably, the basic nitrogen content of the carbotetraene is less than 30 ppm.

[0027] Through the above technical solution, this method, by using the modified amorphous silica-alumina catalyst of the present invention for a two-step non-selective superposition reaction, can significantly improve the total conversion rate of C4 olefins from about 60-80% to 80-95%; after 120 days of continuous operation of the two-step fixed bed, the total conversion rate of C4 olefins is greater than 80%; isobutylene can be basically completely converted; and the separated mixed C4 olefins can be used as high-quality raw materials for alkylation.

[0028] Furthermore, the non-selective superposition method of the present invention can be used to prepare high-octane gasoline components by mixing C4 olefins. Detailed Implementation

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] The present invention provides a non-selective superposition method for C4 olefins, the method comprising: subjecting C4 olefins to a first superposition reaction and a second superposition reaction in the presence of a modified amorphous silica-alumina catalyst.

[0031] The modified amorphous silica-alumina catalyst comprises an amorphous silica-alumina catalyst and a copper-zinc-aluminum component supported thereon. The silica-alumina ratio of the amorphous silica-alumina catalyst is 1.5-3, preferably 1.8-2.5. The copper-zinc-aluminum component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, and z is the number of oxygen atoms satisfying the oxidation states of each metal element. The content of the copper-zinc-aluminum component is 1-10% by mass of the amorphous silica-alumina catalyst, preferably 3-5% by mass, and in the modified amorphous silica-alumina catalyst, 0-valent copper and +1-valent copper account for more than 50% of the total copper content, preferably more than 70%. The conditions for the first superposition reaction include: reaction temperature 160-200℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 The conditions for the second superposition reaction include: reaction temperature 180-240℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 .

[0032] According to a preferred embodiment of the present invention, the conditions for the first superposition reaction include: a reaction temperature of 170-190°C, a reaction pressure of 5-6 MPa, and a liquid hourly space velocity of 0.5-1.2 h⁻¹. -1 ; and / or the conditions for the second superposition reaction include: reaction temperature 180-220℃, reaction pressure 5-6MPa, and liquid hourly space velocity 0.5-1.2h. -1 .

[0033] More preferably, the temperature of the second superposition reaction is 15-30°C higher than the temperature of the first superposition reaction, more preferably 15-25°C higher.

[0034] According to the present invention, the first superposition reaction and the second superposition reaction can be carried out continuously, that is, the product of the first superposition reaction can be directly subjected to the second superposition reaction. Optionally, the C8 component can be separated from the product of the first superposition reaction, and then the separated product can be used to carry out the second superposition reaction. For example, the separation method can be to obtain C4 component liquefied gas from the top of the column and C8 component from the bottom of the vessel by pressure distillation.

[0035] According to the present invention, the non-selective superposition method further includes a step of regenerating the modified amorphous silica-alumina catalyst. Specifically, catalyst regeneration can be performed when the total conversion of C4 olefins in the superposition reaction is less than 80%. Preferably, catalyst regeneration is performed when the total conversion of C4 olefins in the first superposition reaction is less than 60%, and / or when the total conversion of C4 olefins in the second superposition reaction is less than 80%.

[0036] The regeneration preferably employs an online regeneration process. The conditions for online regeneration may include, for example, an oxygen-containing atmosphere, a temperature of 450-600℃, preferably 500-550℃, and a time of 4-10 hours, preferably 4-6 hours. The aforementioned oxygen-containing atmosphere can be, for example, air or other atmospheres containing oxygen, preferably with an oxygen content of 5% or more, such as a mixture of 5-15% oxygen and 85-95% nitrogen.

[0037] The non-selective chelation method of the present invention can be carried out using the above-mentioned modified amorphous silica-alumina catalyst. According to the present invention, in the modified amorphous silica-alumina catalyst, copper exists in the forms of 0, +1, and / or +2 valences. Through hydrogenation reduction pretreatment, the 0-valent copper and +1-valent copper account for more than 50% of the total copper content, enabling the obtained modified amorphous silica-alumina catalyst to possess better C4 olefin chelation catalytic activity. In a specific embodiment of the present invention, the 0-valent copper accounts for 30-50% of the total copper content, and the +1-valent copper accounts for 30-50% of the total copper content; furthermore, the +2-valent copper accounts for less than 30% of the total copper content, for example, 10-30%.

[0038] According to the present invention, the amorphous silica-alumina catalyst described above preferably has the following characteristics, which helps to further improve the conversion rate of C4 olefins and the selectivity of C8 olefins, and is particularly suitable for the synthesis of coking C4 olefins with a basic nitrogen content of 0-30 ppm.

[0039] Preferably, the amorphous silica-alumina catalyst has a pore size of 20-50 nm, more preferably 30-50 nm.

[0040] Preferably, the specific surface area of ​​the amorphous silica-alumina catalyst is less than 250 m². 2 / g, preferably 200-250m 2 / g.

[0041] Preferably, the XRD pattern of the amorphous silica-alumina catalyst has only one diffuse diffraction peak at 25° to 27°.

[0042] According to a preferred embodiment of the present invention, the modified amorphous silica-alumina catalyst is preferably prepared by the following method:

[0043] (1) The copper-zinc-aluminum components are subjected to hydrogenation pretreatment;

[0044] (2) The product obtained in step (1) is mixed with an amorphous silica-alumina catalyst and subjected to a first drying, a first calcination and a hydrothermal treatment in sequence;

[0045] The amorphous silica-alumina catalyst has a silica-alumina ratio of 1.5-3, preferably 1.8-2.5.

[0046] The copper-zinc-aluminum component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, and z is the number of oxygen atoms that satisfy the oxidation states of each metal element.

[0047] According to the present invention, the silicon-to-aluminum ratio of the amorphous silicon-aluminum catalyst can be, for example, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3.

[0048] According to the present invention, a can be 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10, etc.; b and c can each independently be 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5, etc.

[0049] According to a preferred embodiment of the present invention, the amorphous silica-alumina catalyst has the following general formula composition: (0-0.3)Na2O·(50-80)SiO2·(20-50)Al2O3.

[0050] According to the present invention, in step (1), in order to obtain the copper-zinc-aluminum component having the above composition, a co-precipitation method can be used for preparation. Specifically, the preparation method of the copper-zinc-aluminum component may include, for example, contacting a precipitant with a copper source, a zinc source, and a second aluminum source under conditions of pH 2-9, preferably 5-8.5, followed by a second aging, washing, a second drying, and a second calcination to obtain the copper-zinc-aluminum component.

[0051] As the copper source, zinc source, and second aluminum source, soluble salts containing copper, zinc, and aluminum are preferably used, with nitrates or hydrochlorides being more preferred. The copper source may be selected from one or more of copper nitrate, copper sulfate, and copper chloride. The zinc source may be selected from one or more of zinc nitrate, zinc sulfate, and zinc chloride. The second aluminum source may be selected from one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride. Additionally, as the precipitant, it may be an alkali (such as sodium hydroxide, potassium hydroxide), an alkaline salt (such as sodium carbonate, potassium carbonate), or ammonia, such as sodium carbonate.

[0052] The contact between the precipitant and the copper source, zinc source, and second aluminum source can be achieved by adding a solution containing the copper source, zinc source, and second aluminum source to the precipitant solution, or by adding the precipitant solution to a solution containing the copper source, zinc source, and second aluminum source, or by contacting the solutions containing the copper source and second aluminum source, and the solutions containing the zinc source and second aluminum source, separately with the precipitant solution and then mixing the contact products. In the above solution, the concentrations of the zinc source, copper source, and second aluminum source (calculated as zinc ion, copper ion, or aluminum ion) can each be independently 0.1-5 mol / L, preferably 0.2-2.5 mol / L, more preferably 1-2.5 mol / L. The concentration of the precipitant solution can be 0.1-5 mol / L, preferably 0.5-2 mol / L. The volume ratio of the precipitant solution to the total volume of the zinc source, copper source, and second aluminum source is 1-10:1, preferably 3-8:1.

[0053] As a preferred method for preparing the copper-zinc-aluminum component, the conditions for the second aging may include: a temperature of 30-80℃, preferably 50-70℃; a time of 2-20 hours, preferably 5-10 hours; and a pH of 6-9, preferably 7.5-8.5. The conditions for the second drying may include: a temperature of 80-150℃, preferably 105-120℃; and a time of 1-6 hours, preferably 2-4 hours. The conditions for the second calcination may include: a temperature of 200-450℃, preferably 300-380℃; and a time of 1-6 hours, preferably 2-4 hours.

[0054] According to the present invention, in step (1), the copper-zinc-aluminum component is made suitable for modification of the C4 olefin non-selective chelate catalyst through hydrogenation pretreatment, thereby facilitating the obtaining of a modified amorphous silica-alumina catalyst with better non-selective chelate effect. Preferably, the hydrogenation pretreatment results in 0-valent copper and +1-valent copper accounting for more than 50% of the total copper content in the copper-zinc-aluminum component, more preferably more than 70%; more preferably, the hydrogenation pretreatment results in 30-50% of the total copper content in the copper-zinc-aluminum component and 30-50% of the total copper content in the +1-valent copper.

[0055] The conditions for the hydrogenation pretreatment may include: reduction with hydrogen or a hydrogen-containing gas at 150-300°C and 0.1-8 MPa for 2-40 hours; preferably, reduction at 200-280°C and 3-6 MPa for 5-10 hours. The hydrogen-containing gas may be a mixture of hydrogen and an inert gas, wherein the hydrogen content is 5-20% by volume.

[0056] According to the present invention, in step (2), the amorphous silicon-aluminum catalyst can be an amorphous silicon-aluminum catalyst commonly used for C4 non-selective superposition, for example, it can be prepared by the following preparation method: a silicon source and a first aluminum source are subjected to a first aging under the conditions of pH 8-10.5 and 40-80°C, and then the resulting aging product is washed and filtered, and then the filtered solid precipitate is contacted with an acidic solution and then filtered and dried.

[0057] Specifically, the silicon source may be selected from one or more of water glass, sodium silicate, alkaline silica sol, tetraethoxysilane, and tetramethoxysilane, and the first aluminum source may be selected from one or more of aluminum nitrate, aluminum sulfate, or aluminum chloride. Furthermore, the weight ratio of the silicon source (based on silicon oxide) to the first aluminum source (based on aluminum oxide) may be 1:(0.25-1), preferably 1:(0.4-0.7).

[0058] Preferably, the pH is adjusted to the aforementioned range by adding an alkaline solution. The alkaline solution used can be selected from one or more of sodium hydroxide, potassium hydroxide, ammonia, and sodium aluminate. When sodium aluminate is used as the alkaline solution, its aluminum content is included in the first aluminum source. Furthermore, the conditions for the first aging process may include: a temperature of 40-80°C, preferably 60-75°C; a time of 5-20 hours, preferably 10-15 hours; and a pH of 8-10.5, preferably 9-10.

[0059] Preferably, the contact between the filtered solid precipitate and the acidic solution is carried out at a weight ratio of precipitate dry basis: acidic substance: H2O = 1:(0.02-0.2):(5-30), preferably 1:(0.05-0.15):(10-20). The acidic substance is the solute in the acidic solution. The contact is preferably carried out at 20-60°C, preferably 30-50°C, for at least 0.2 hours, preferably 0.2-1 hours. The acidic solution used can be an acid or a solution of a strong acid-weak base salt, for example, a solution selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, ammonium sulfate, ammonium chloride, and ammonium nitrate, with a concentration of 0.01-2 mol / L, preferably 0.1-1 mol / L. Subsequent drying conditions can be, for example, 80-110°C for 1-5 hours.

[0060] According to the present invention, in step (2), the amorphous silica-alumina catalyst is modified by using a copper-zinc-aluminum component. The amount of the copper-zinc-aluminum component is 1-10% by mass of the amorphous silica-alumina catalyst, preferably 3-5% by mass, thereby improving the C4 olefin conversion and C8 olefin selectivity of the obtained catalyst. Furthermore, when the product obtained in step (1) is mixed with the amorphous silica-alumina catalyst, it is preferable to stir and mix for more than 3 minutes, for example 5-20 minutes, so that the hydrogenated copper-zinc-aluminum component is fully mixed with the amorphous silica-alumina catalyst.

[0061] According to the present invention, in step (2), the conditions for the first drying may include: a temperature of 80-150°C, preferably 95-120°C, more preferably 105-120°C; and a time of 1-6 hours, preferably 2-4 hours. The conditions for the first calcination may include: under an inert atmosphere, a temperature of 400-580°C, preferably 400-550°C, more preferably 500-550°C; and a time of 1-6 hours, preferably 2-4 hours. The inert atmosphere may be a nitrogen atmosphere and / or an inert gas atmosphere such as argon. The conditions for the hydrothermal treatment may include: a temperature of 200-400°C, preferably 240-350°C, more preferably 240-300°C; a pressure of atmospheric pressure to 0.5 MPa, preferably atmospheric pressure to 0.2 MPa; and a time of 1-8 hours, preferably 2-5 hours, more preferably 2-4 hours.

[0062] In the non-selective superposition method of the present invention, the superposition reaction is preferably carried out in a fixed-bed reactor, which can be either an upflow or a downflow reactor, with a downflow reactor being preferred. To facilitate the reaction, the modified amorphous silica-alumina catalyst used has a particle size of 20-40 mesh.

[0063] The mixed C4 used as the reaction feedstock has no particular source limitation and can be C4 byproducts of ethylene cracking units and refinery C4 components. Refinery C4 includes C4 byproducts from catalytic cracking, viscous cracking, thermal cracking, and delayed coking in refineries; C4 byproducts from aromatics reforming; C4 byproducts from coal chemical methanol-to-olefins units; and recovered C4 from oilfield gas and natural gas. The amount of saturated C4 hydrocarbons in the feedstock does not affect this method, but excessive saturated hydrocarbons will increase the reaction temperature and energy consumption. Therefore, it is preferable that the content of saturated C4 hydrocarbons in the mixed C4 is below 70% by volume.

[0064] According to some specific embodiments of the present invention, the composition of the C4 olefin may include, for example, n-butane, isobutane, n-butene, isobutene, cis-butene, trans-butene, etc., and preferably the butene content (including n-butene, isobutene, cis-butene and trans-butene) in the C4 olefin is 20-80%.

[0065] Furthermore, by employing the modified amorphous silica-alumina catalyst of this invention, the non-selective fusion method of this invention can be applied to C4 fusions from coking sources. Even if the fusion feedstock has a basic nitrogen content of less than 30 ppm, it can still achieve good C4 olefin conversion and C8 olefin selectivity, and has a better catalyst activity retention effect, extending the catalyst activation interval time.

[0066] In this invention, the alkaline nitrogen content of the composite raw material can be, for example, 0 ppm, 1 ppm, 2 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm or 30 ppm.

[0067] In this invention, the alkaline nitrogen content is determined by the industry standard SH / T 0162-1992, the method for determining alkaline nitrogen in petroleum products; the valence state distribution of copper is obtained by peak analysis using XPS Auger copper spectrometry.

[0068] The present invention will be described in detail below through embodiments.

[0069] Preparation Example 1

[0070] This preparation example illustrates the use of n Cu / n Zn A method for preparing modified amorphous silica-alumina catalysts by modifying amorphous silica-alumina catalysts with a 1:1 copper-zinc-aluminum composition.

[0071] (1) Preparation of copper-zinc-aluminum components n was prepared by co-precipitation method Cu / n Zn It is a 1 / 1 copper-zinc-aluminum composition.

[0072] a) Dissolve 0.5 mol Cu(NO3)2·3H2O and 0.5 mol AlCl3·6H2O in 200 mL of deionized water to prepare mixed solution A, and dissolve 0.5 mol Zn(NO3)2·6H2O and 0.5 mol AlCl3·6H2O in 200 mL of deionized water to prepare mixed solution B.

[0073] b) Add 50 mL of deionized water to reaction vessel 1. Add mixed solution A and sodium carbonate solution (concentration 1.0 mol / L) to reaction vessel 1 in parallel and stir. The molar ratio of sodium carbonate to the total amount of copper and aluminum is 2.0. The temperature is 60℃, the pH value is 7.5, and the time is 1.0 hour to obtain slurry I.

[0074] c) Add 50 mL of deionized water to reaction vessel 2. Add mixed solution B and sodium carbonate solution (concentration 1.0 mol / L) to reaction vessel 2 in parallel. The molar ratio of sodium carbonate to the total amount of zinc and aluminum is 2.0. The temperature is 60℃, the pH value is 9.2, and the time is 2.0 hours to obtain slurry II.

[0075] d) Mix slurry I and II in a volume ratio of 1:1. The resulting mixed slurry is aged under stirring conditions. The aging pH value is 7.8, the aging temperature is 70℃, and the aging time is 5.5 hours. The aged slurry is filtered, and the filter cake is washed 3 times with deionized water. The filter cake is dried at 110℃ for 5 hours and calcined at 360℃ for 3.5 hours.

[0076] (2) Hydrogenation pretreatment of copper-zinc-aluminum components

[0077] The copper-zinc-aluminum component obtained in step (1) was pressed into 20-40 mesh solid particles, and 20.0 g was loaded into a fixed-bed reactor. 10% hydrogen gas (a mixture of 10% hydrogen and 90% nitrogen, hereinafter the same) was introduced at a pressure of 0.20 MPa, and the temperature was increased at a rate of 0.5 °C / min within the range of room temperature to 280 °C. The catalyst was reduced at 280 °C for 4.0 h, and then cooled to room temperature. XPS analysis revealed that 0-valent copper accounted for 39.5% of the total copper content, +1-valent copper accounted for 38.2%, and +2-valent copper accounted for 22.3%.

[0078] (3) Preparation of amorphous silica-alumina catalysts

[0079] The silicon source (35g SiO2 / L water glass, 1000mL) and the alkaline solution (sodium hydroxide, 1.0mol / L, 250mL) were thoroughly mixed at 60℃. Then, the aluminum source (90g Al2O3 / L sodium aluminate, 300mL) was added under stirring. The pH of the resulting slurry was adjusted to 9.4. The slurry was then dynamically aged at a constant temperature of 70℃ for 12 hours. After washing and filtration, the resulting solid precipitate was contacted with an acidic solution (NH4Cl, 0.5mol / L) at 60℃ for 0.5 hours at a weight ratio of precipitate dry basis: NH4Cl: H2O = 1:0.1:15. After filtration, the precipitate was dried at 100℃ for 3 hours to obtain an amorphous silicon-aluminum catalyst.

[0080] The XRD pattern of this amorphous silica-alumina catalyst showed only one diffuse diffraction peak at 25°–27°, indicating a pore size of 35.4 nm and a specific surface area of ​​248 m². 2 / g, with a silicon-to-aluminum ratio of 2.24.

[0081] (4) Modification treatment of amorphous silica-alumina catalysts

[0082] Add 3.5g of copper-zinc-aluminum components to 100g of amorphous silica-alumina catalyst, stir evenly, dry at 100℃ for 2 hours, then calcine at 450℃ for 3 hours under nitrogen atmosphere, and then perform hydrothermal treatment at 350℃ for 5 hours to obtain modified amorphous silica-alumina catalyst.

[0083] Example 1

[0084] (1) A fixed bed was used, and the modified amorphous silica-alumina catalyst obtained in Preparation Example 1 was used. The mixed C4 olefin products from catalytic cracking and coking at Cangzhou Refinery (in mol%: n-butane 18.783%, isobutane 38.258%, n-butene 11.153%, isobutene 10.096%, cis-butene 8.364%, trans-butene 12.086%, C3 0.56%, isopentene 0.65%, butadiene 0.05%; basic nitrogen content was 5.0 ppm) were used as raw materials. The reaction was carried out at a reaction temperature of 180℃, a reaction pressure of 5.2 MPa, and a liquid hourly space velocity of 0.50 h⁻¹. -1 Under certain conditions, a non-selective superposition reaction is carried out.

[0085] (2) A fixed bed was used, with the modified amorphous silica-alumina catalyst obtained in Preparation Example 1 as the raw material, and the product of the first step of non-selective superposition was used. The reaction was carried out at a reaction temperature of 200°C, a reaction pressure of 5.8 MPa, and a liquid hourly space velocity of 0.50 h⁻¹. -1 Under certain conditions, a non-selective superposition reaction is carried out.

[0086] The total conversion rates of C4 olefins on days 30 and 60 of the two-step superposition reaction are shown in Table 1.

[0087] Example 2

[0088] The modified amorphous silica-alumina catalyst was prepared according to the method of Preparation Example 1, except that in the preparation of the copper-zinc-aluminum component, slurries I and II were mixed at a volume ratio of 2:1 to obtain copper-zinc-aluminum component n. Cu / n Zn The modified amorphous silica-alumina catalyst is 2 / 1.

[0089] The modified amorphous silica-alumina catalyst was used to carry out a non-selective superposition reaction according to the method of Example 1, the only difference being that in step (1), the reaction temperature was 190°C, the reaction pressure was 5.0 MPa, and the liquid hourly space velocity was 0.6 h⁻¹. -1 Under the conditions of 220℃, a non-selective superposition reaction was carried out; in step (2), the reaction temperature was 220℃, the reaction pressure was 5.5MPa, and the liquid hourly space velocity was 0.6h. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0090] Example 3

[0091] The modified amorphous silica-alumina catalyst was prepared according to the method of Preparation Example 1, except that in the preparation of the copper-zinc-aluminum component, slurries I and II were mixed at a volume ratio of 1:2 to obtain copper-zinc-aluminum component n. Cu / n Zn It is a modified amorphous silica-alumina catalyst with a ratio of 1 / 2.

[0092] The modified amorphous silica-alumina catalyst was used to carry out a non-selective superposition reaction according to the method of Example 1, the only difference being that in step (1), the reaction temperature was 185°C, the reaction pressure was 5.2 MPa, and the liquid hourly space velocity was 0.6 h⁻¹. -1 Under the conditions of 210℃, 5.5MPa, and 0.6h⁻¹, a non-selective superposition reaction was carried out; step (2) was carried out at a reaction temperature of 210℃, a reaction pressure of 5.5MPa, and a liquid hourly space velocity of 0.6h⁻¹. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0093] Example 4

[0094] The two-step non-selective chelation reaction was carried out according to the method of Example 1, except that the basic nitrogen content in the mixed C4 olefin product used was 1.0 ppm. The results are shown in Table 1.

[0095] Example 5

[0096] The two-step non-selective superposition reaction was carried out according to the method of Example 1, except that in step (1), the reaction temperature was 170°C, the reaction pressure was 5.0 MPa, and the liquid hourly space velocity was 0.7 h⁻¹. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0097] Example 6

[0098] The two-step non-selective superposition reaction was carried out according to the method of Example 1, except that in step (2), the reaction temperature was 240°C, the reaction pressure was 5.2 MPa, and the liquid hourly space velocity was 0.6 h⁻¹. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0099] Example 7

[0100] The two-step non-selective superposition reaction was carried out according to the method of Example 1, except that in step (2), the reaction temperature was 190°C, the reaction pressure was 4.5 MPa, and the liquid hourly space velocity was 1.5 h⁻¹. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0101] Example 8

[0102] The two-step non-selective superposition reaction was carried out according to the method of Example 1, except that in step (2), the reaction temperature was 200°C, the reaction pressure was 6.5 MPa, and the liquid hourly space velocity was 1.8 h⁻¹. -1 Under the specified conditions, a non-selective superposition reaction was carried out. The results are shown in Table 1.

[0103] Comparative Example 1

[0104] The modified amorphous silica-alumina catalyst was prepared according to the method of Preparation Example 1, but without hydrogenation pretreatment.

[0105] Using the modified amorphous silica-alumina catalyst described above, a two-step non-selective superposition reaction was carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0106] Comparative Example 2

[0107] Amorphous silica-alumina catalysts were prepared according to the method of Example 1, but without modification. The amorphous silica-alumina catalysts were then used directly in the same two-step non-selective superposition reaction as in Example 1. The results are shown in Table 1.

[0108] Table 1

[0109]

[0110] As can be seen from the results in Table 1, the non-selective superposition method of the present invention can achieve a total conversion rate of over 80% for C4 olefins after 60 days of reaction.

[0111] A comparison of Examples 1 and Examples 5-8 shows that by adopting preferred superposition reaction conditions, the total conversion rate of C4 olefins can be further improved.

[0112] A comparison of the results of Example 1 and Comparative Examples 1-2 shows that, since no hydrogenation pretreatment was performed in Comparative Example 1 and no modification treatment was performed in Comparative Example 2, the total conversion rate of C4 olefins in both examples is much lower than that in Example 1.

[0113] Example 9

[0114] The non-selective chelate reaction was carried out according to the method of Example 1 until the total conversion of C4 olefins in step (1) was less than 60% or the total conversion of C4 olefins in step (2) was less than 75%. The catalyst was then regenerated online in the following manner: the reactor temperature was raised to 550°C for 6 hours under mixed gas (10% oxygen and 90% nitrogen), and then replaced with nitrogen for later use.

[0115] Using the modified amorphous silica-alumina catalyst described above, the mixed C4 stoichiometric reaction was carried out in the same manner as in Example 1. The total conversion rates of C4 olefins on day 30 and day 60 of step (2) were 90.3% and 84.9%, respectively.

[0116] The above results demonstrate that the modified amorphous silica-alumina catalyst of the present invention has good regeneration performance, and the non-selective superposition performance of the regenerated modified amorphous silica-alumina catalyst is still significantly better than that of the unmodified amorphous silica-alumina catalyst.

[0117] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A non-selective superposition method for C4 olefins, characterized in that, The method includes: subjecting a carbide olefin to a first superposition reaction and a second superposition reaction in the presence of a modified amorphous silica-alumina catalyst; The modified amorphous silica-alumina catalyst comprises an amorphous silica-alumina catalyst and a copper-zinc-aluminum component supported thereon. The SiO2 / Al2O3 silica-alumina molar ratio of the amorphous silica-alumina catalyst is 1.5-3. The copper-zinc-aluminum component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, z is the number of oxygen atoms that satisfy the valence of each metal element, the content of the copper-zinc-aluminum component is 1-10% by mass of the amorphous silicon-aluminum catalyst, and in the modified amorphous silicon-aluminum catalyst, 0-valent copper and +1-valent copper account for more than 50% of the total copper content. The conditions for the first superposition reaction include: reaction temperature 160-200℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 ; The conditions for the second superposition reaction include: reaction temperature 180-240℃, reaction pressure 4-10MPa, and liquid hourly space velocity 0.2-2h. -1 .

2. The non-selective superposition method for C4 olefins according to claim 1, wherein, The amorphous silicon-aluminum catalyst has a SiO2 / Al2O3 silicon-aluminum molar ratio of 1.8-2.5, and the copper-zinc-aluminum component has the following general formula: Cu a ZnAl b O z In the formula, a is 0.1-10, b is 0.1-5, z is the number of oxygen atoms satisfying the valence of each metal element, the content of the copper-zinc-aluminum component is 3-5% by mass of the amorphous silicon-aluminum catalyst, and in the modified amorphous silicon-aluminum catalyst, 0-valent copper and +1-valent copper account for more than 70% of the total copper content.

3. The non-selective superposition method for C4 olefins according to claim 1, wherein, The conditions for the first superposition reaction include: reaction temperature 170-190℃, reaction pressure 5-6MPa, and liquid hourly space velocity 0.5-1.2h. -1 ; and / or The conditions for the second superposition reaction include: reaction temperature 180-220℃, reaction pressure 5-6MPa, and liquid hourly space velocity 0.5-1.2h. -1 .

4. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The non-selective superposition method also includes a step of regenerating the modified amorphous silica-alumina catalyst.

5. The non-selective superposition method for carbotetraenes according to claim 4, wherein, The regeneration is an online regeneration.

6. The non-selective superposition method of carbotetraenes according to claim 4, wherein, The regeneration conditions include: an oxygen-containing atmosphere, a temperature of 450-600℃, and a time of 4-10 hours.

7. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, In the modified amorphous silica-alumina catalyst, 0-valent copper accounts for 30-50% of the total copper content, and +1-valent copper accounts for 30-50% of the total copper content.

8. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The amorphous silica-alumina catalyst has a pore size of 20-50 nm.

9. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The specific surface area of ​​the amorphous silica-alumina catalyst is less than 250 m². 2 / g.

10. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The XRD pattern of the amorphous silica-alumina catalyst shows only one diffuse diffraction peak at 25°–27°.

11. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The modified amorphous silica-alumina catalyst was prepared by the following method: (1) The copper-zinc-aluminum components are subjected to hydrogenation pretreatment; (2) The amorphous silica-alumina catalyst is mixed with the product obtained in step (1) and subjected to first drying, first calcination and hydrothermal treatment in sequence.

12. The non-selective lamination method for C4 olefins according to claim 11, wherein, In step (2), the conditions for the first calcination include: an inert atmosphere, a temperature of 400-580℃, and a time of 1-5 hours.

13. The non-selective superposition method of carbotetraenes according to claim 11, wherein, In step (1), the preparation method of the copper-zinc-aluminum component includes: contacting the precipitant with a copper source, a zinc source and a second aluminum source under pH 5-9 conditions, and then undergoing a second aging, washing, a second drying and a second calcination to obtain the copper-zinc-aluminum component.

14. The non-selective lamination method for C4 olefins according to claim 13, wherein, The precipitant is an alkali or an alkaline salt.

15. The non-selective lamination method for carbotetraenes according to claim 11, wherein, In step (1), the conditions for hydrogenation pretreatment include: reduction with hydrogen at 150-300℃ and 0.1-8MPa for 2-40 hours.

16. The non-selective lamination method for carbotetraenes according to claim 11, wherein, In step (1), the conditions for hydrogenation pretreatment include: reduction with hydrogen-containing gas at 150-300℃ and 0.1-8MPa for 2-40 hours.

17. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The superposition reaction is carried out in a fixed-bed reactor.

18. The non-selective assemblage method for carbotetraenes according to any one of claims 1-3, wherein, The modified amorphous silica-alumina catalyst has a particle size of 20-40 mesh.

19. The non-selective stoichiometry method for C4 olefins according to any one of claims 1-3, wherein the basic nitrogen content of the C4 olefin is less than 30 ppm.

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