Alkylation process

Abstract

The invention relates to the technical field of alkylation, in particular to an alkylation method. The method comprises the following steps: carrying out alkylation reaction on isoparaffin and ethylene in the presence of a hydrogen-containing atmosphere and a solid acid catalyst, the concentration of hydrogen in the hydrogen-containing atmosphere is 1-100% by volume; the solid acid catalyst comprises a molecular sieve, a binder and a hydrogenation active component, based on the dry basis weight of the catalyst, the content of the molecular sieve is 20-90 wt%, the content of the binder is 5-79.99 wt%, and the content of the hydrogenation active component in terms of elements is 0.01-5 wt%; compared with the 200 DEG C pyridine infrared total acid content of the molecular sieve, the 200 DEG C pyridine infrared total acid content of the catalyst is increased by 30-110%; compared with the mesoporous volume of the molecular sieve, the mesoporous volume of the catalyst is increased by 70-215%. The method can improve the conversion rate and yield of the catalyst in the alkylation reaction of isoparaffin and ethylene.

Description

Technical Field

[0001] The present invention relates to the technical field of alkylation, and in particular to an alkylation method. Background Art

[0002] The reaction of isoparaffins and olefins to form alkylate oil under the action of acidic catalysts is an important process for producing high-octane gasoline components in the petroleum industry. This reaction is an organic addition reaction between alkane molecules and olefin molecules following the positive carbon ion chain reaction process under the action of acidic catalysts.

[0003] With the continuous improvement of environmental protection requirements and energy conservation and emission reduction requirements, the number of hybrid vehicles is growing in order to reduce automobile fuel consumption. Since the engine of hybrid vehicles needs to be started and stopped constantly, a certain amount of lighter high-octane components will help the engine start. Dimethylbutane and isopentane produced by the alkylation of isobutane and ethylene are ideal light gasoline blending components due to their high octane number, good combustion performance, and the absence of sulfides, aromatics, and olefins.

[0004] Molecular sieves have a regular three-dimensional pore structure. Their suitable acidity and low price facilitate the diffusion of reactant molecules in the molecular sieve pores and their reaction at the acidic center. Molecular sieve catalysts are widely used in petrochemical and other fields, especially in catalytic cracking, hydrogenation, reforming, isobutane butene alkylation, benzene and olefin alkylation. Therefore, the research on molecular sieve catalysts not only has important academic value, but also has broad application prospects.

[0005] However, molecular sieve solid acid catalysts are prone to coking and deactivation during the catalytic alkylation of isobutane with ethylene. To achieve continuous production, the life of the catalyst needs to be increased and the catalyst needs to be regenerated frequently. For molecular sieve catalysts, increasing the life of the catalyst can increase the total acid content of the catalyst to inhibit side reactions, and improve the diffusion performance of the catalyst so that the generated macromolecular products can diffuse out of the pores in a timely manner. In general, the diffusion performance of molecular sieve catalysts is achieved by improving the pore structure of the catalyst. In general, pore expansion of molecular sieve catalysts will destroy the acid sites of the catalyst, resulting in a decrease in the total acid content. Some Na+ still remains in the catalyst after a single calcination. + Near the acidic site, it can protect the acidic site from damage.

[0006] It is generally believed that the coking reaction on the catalyst starts with low-level olefins, followed by polymerization and hydrogen transfer reactions to generate polyolefin species and low-ring aromatics, and then hydrogen transfer, alkylation and cyclization reactions continue to form non-volatile coke deposits with multi-ring structures. The alkylation reaction is carried out at a relatively low temperature, and the carbon deposits on the catalyst are generally considered to be long-chain alkanes, olefins and monocyclic aromatic compounds. These carbon deposits are called soft cokes, which can be easily removed from the acidic positions of the catalyst by hydrogenation reactions. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems existing in the prior art and provide a solid alkylation method. The method uses a solid acid catalyst with a higher pyridine infrared total acid content and a specific mesoporous volume. The method can improve the conversion rate and yield of the catalyst in the alkylation reaction of isoparaffin and ethylene, and the operation is simple and the cost is low.

[0008] In order to achieve the above object, the present invention provides an alkylation method, wherein the method comprises: in the presence of a hydrogen-containing atmosphere and a solid acid catalyst, carrying out an alkylation reaction on isoparaffin and ethylene; wherein the concentration of hydrogen in the hydrogen-containing atmosphere is 1-100 volume %; the solid acid catalyst comprises a molecular sieve, a binder and a hydrogenation active component, based on the dry weight of the catalyst, the content of the molecular sieve is 20-90wt%, the content of the binder is 5-79.99wt%, and the content of the hydrogenation active component in terms of element is 0.01-5wt%; the 200°C pyridine infrared total acidity of the catalyst is increased by 30-110% compared with the 200°C pyridine infrared total acidity of the molecular sieve; and the mesopore volume of the catalyst is increased by 70-215% compared with the mesopore volume of the molecular sieve.

[0009] The alkylation method provided by the present invention generates dimethylbutane and isopentane with high octane number through reaction, reduces the loss of catalyst performance and structure caused by catalyst regeneration, reduces the energy loss caused by high-temperature hydrogen regeneration, reduces carbon emissions, and reduces reaction costs.

[0010] The alkylation method provided by the present invention reacts in a hydrogen atmosphere, utilizes the platinum loaded on the catalyst to produce a hydrogenolysis function, inhibits the generation of carbon deposits, prolongs the reaction cycle, has no negative impact on the acidity and stability of the catalyst itself, and realizes long-term continuous operation of the catalyst, which is beneficial to industrial continuous production and greatly saves production costs.

[0011] The alkylation method provided by the present invention uses a solid acid catalyst with a high pyridine infrared total acid content and a specific mesoporous volume. Preferably, in the process of preparing the solid acid catalyst, the inventors of the present invention have found in their research that after a Na-type molecular sieve is subjected to an ammonium exchange, it is shaped and calcined with a binder, and then the catalyst is subjected to a crystallization treatment, so that the remaining Na in the catalyst can be + The mesoporous volume and acid accessibility of the catalyst are increased while protecting the acidity of the catalyst from being destroyed, and the loaded active metal can enter the Na cage, thereby improving the metal dispersion and effectively extending the life of the catalyst.

[0012] Compared with the prior art where the catalyst reaction cycle is short and leads to frequent reactor switching, the alkylation method provided by the present invention greatly improves the manpower and material costs in the reaction process, extends the catalyst life and thus extends the reaction cycle, which can effectively reduce the frequent switching and regeneration of the reactor, thereby saving costs and reducing carbon emissions. DETAILED DESCRIPTION

[0013] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0014] The invention provides an alkylation method, wherein the method comprises: in the presence of a hydrogen-containing atmosphere and a solid acid catalyst, carrying out an alkylation reaction on isoparaffin and ethylene; wherein the concentration of hydrogen in the hydrogen-containing atmosphere is 1-100 volume percent; the solid acid catalyst comprises a molecular sieve, a binder and a hydrogenation active component, based on the dry weight of the catalyst, the content of the molecular sieve is 20-90wt%, the content of the binder is 5-79.99wt%, and the content of the hydrogenation active component in terms of elements is 0.01-5wt%; the 200°C pyridine infrared total acidity of the catalyst is increased by 30-110% compared with the 200°C pyridine infrared total acidity of the molecular sieve; and the mesopore volume of the catalyst is increased by 70-215% compared with the mesopore volume of the molecular sieve.

[0015] The method provided by the present invention selects a solid acid catalyst having a higher pyridine infrared total acid content and a higher mesopore volume, the pyridine infrared total acid content and the mesopore volume have a specific matching relationship, and the catalyst has a longer service life; further, in the method provided by the present invention, the solid acid catalyst is loaded with a component with hydrogenation activity, which dissociates hydrogen into H protons during the reaction process, promotes the hydrogen transfer reaction in the alkylation reaction, inhibits the generation of carbon deposition, and greatly improves the catalyst life.

[0016] According to a preferred embodiment of the present invention, based on the dry weight of the catalyst, the content of the molecular sieve is 25-84wt%, the content of the binder is 15-75wt%, and the content of the hydrogenation active component in terms of element is 0.1-1wt%.

[0017] In the present invention, the content of each substance in the catalyst is measured by X-ray fluorescence spectrometry (XRF), and the specific test conditions include: the test conditions are: tungsten target, excitation voltage 40kV, excitation current 50mA. The sample powder is pressed into tablets, and the applied pressure is generally 500-1000kPa. The standard sample is measured and a working curve is established, and the content is found on the working curve by interpolation.

[0018] According to a preferred embodiment of the present invention, the total pyridine infrared acid content of the catalyst at 200°C is increased by 52-80% compared with the total pyridine infrared acid content of the molecular sieve at 200°C. The advantage of adopting this preferred embodiment is that the total pyridine acid content of the obtained catalyst is more suitable for ethylene isobutane alkylation reaction.

[0019] According to a preferred embodiment of the present invention, the mesopore volume of the catalyst is increased by 110-215% compared with the mesopore volume of the molecular sieve. The advantage of adopting this preferred embodiment is that the increase in the mesopore volume of the catalyst is mainly concentrated on the destruction of the Na cage, and has no obvious effect on the original pore structure. On the basis of ensuring the original acid content, the B acid site of the Na cage is exposed, thereby increasing the B acid content of the catalyst and the accessibility of the acid center.

[0020] In the present invention, "dry basis weight" refers to the mass of a unit mass of catalyst after calcination at 600°C for 4 hours.

[0021] In the present invention, the pyridine adsorption infrared acid amount of the alkylation solid acid catalyst is determined as follows, the instrument is a BrukerTensor II Fourier transform infrared spectrometer, the test process is: take about 25 mg of the catalyst sample 20MPa tablet for 5 minutes, place it in the infrared spectrometer in-situ cell and seal it, heat it to 450°C at a rate of 10°C / min, and evacuate it to 10 -6 Pa for 2h, cooled to room temperature, statically saturated adsorbed pyridine, then vacuumed, heated to 200℃ and 350℃ in steps to desorb the adsorbed pyridine, measured the infrared spectra at the two temperatures and integrated them to calculate the infrared spectrum using the formula. -1 The absorption peak at 1450cm -1 The absorption peak is attributed to the L acidic site.

[0022] C is the concentration of B acid or L acid (mmol / g), C B With C L The calculation formula is:

[0023] C B =1.88A B R 2 / W (Formula 1)

[0024] CL =1.42A L R 2 / W (Formula 2)

[0025] A is the integrated area of ​​the B acid or L acid absorption peak; R is the radius of the sample piece (cm); W is the mass of the sample piece (mg).

[0026] In the present invention, it can be understood that the total pyridine infrared acid content of different hydrogen-type molecular sieves may be different. For example, the total pyridine infrared acid content of HX type molecular sieve at 200°C is about 360 μmol / g, the total pyridine infrared acid content of HY type molecular sieve at 200°C is about 310 μmol / g, and the total pyridine infrared acid content of Hβ type molecular sieve at 200°C is about 560 μmol / g.

[0027] In the present invention, it is understood that the acid amount measured at 200° C. is the total acid amount of the catalyst and the molecular sieve, and the acid amount measured at 350° C. is the strong acid amount of the catalyst and the molecular sieve.

[0028] According to a preferred embodiment of the present invention, the molecular sieve is at least one of X-type, Y-type and β-type molecular sieves, preferably Y-type molecular sieve. The advantage of adopting this preferred embodiment is that the preparation route of Y-type molecular sieve is very mature and suitable for ethylene isobutane alkylation reaction.

[0029] According to a preferred embodiment of the present invention, the binder is selected from at least one of alumina, silica, titania, kaolin and montmorillonite, preferably at least one of alumina, silica and titania.

[0030] According to a preferred embodiment of the present invention, the aluminum oxide is aluminum oxide containing pseudo-boehmite phase and / or γ phase.

[0031] According to a preferred embodiment of the present invention, the hydrogenation active component is selected from at least one of Pt, Pd, Ru and Ir, preferably Pt and / or Pd, and more preferably Pt. The advantages of adopting this preferred embodiment are that the loading amount of Pt is small, the hydrogenation effect is better than other metals, the effect on the acidity and pore structure of the catalyst is small, and it is beneficial to improve the life and selectivity of the catalyst.

[0032] According to a preferred embodiment of the present invention, the content of Pt in terms of element is 0.1-0.5 wt % based on the dry weight of the catalyst. The advantages of adopting this preferred embodiment are that while reducing the loading of the precious metal Pt and reducing the cost of the catalyst, the proportion of active centers in the catalyst is increased, and the coverage of the acid sites of the catalyst by metal particles is reduced, thereby improving the activity and stability of the catalyst.

[0033] According to a preferred embodiment of the present invention, the molecular sieve is an X-type molecular sieve, the unit cell constant of the catalyst is 2.46-2.485 nm, the total acidity of pyridine infrared at 200 ° C is greater than 360 μmol / g, preferably the total acidity of pyridine infrared at 200 ° C is 430-540 μmol / g, and the mesopore volume is 0.048-0.106 cm 3 / g.

[0034] According to a preferred embodiment of the present invention, the molecular sieve is a Y-type molecular sieve, the unit cell constant of the catalyst is 2.441-2.466 nm, the total acidity of pyridine infrared at 200 ° C is greater than 310 μmol / g, preferably the total acidity of pyridine infrared at 200 ° C is 372-465 μmol / g, and the mesopore volume is 0.07-0.128 cm 3 / g.

[0035] According to a preferred embodiment of the present invention, the molecular sieve is a β molecular sieve, the unit cell constant of the catalyst is 1.249-1.262 nm, the total acidity of pyridine infrared at 200 ° C is greater than 560 μmol / g, preferably the total acidity of pyridine infrared at 200 ° C is 670-840 μmol / g, and the mesopore volume is 0.024-0.051 cm 3 / g.

[0036] The catalyst unit cell constant referred to in the present invention is the unit cell constant of the molecular sieve in the catalyst, which is well known to those in the industry and is measured by fitting the unit cell of the spectrum in the standard XRD spectrum library using an X-ray diffraction method (hereinafter referred to as XRD). Different sodium-type molecular sieves may have different unit cell constants, for example, the unit cell constant of sodium X-type molecular sieve is generally about 2.485nm, the unit cell constant of sodium Y-type molecular sieve is generally about 2.466nm, and the unit cell constant of sodium β-type molecular sieve is generally about 1.262nm.

[0037] In the present invention, the mesopore volume of the catalyst is measured by the BET method. Different sodium molecular sieves may have different mesopore volumes. For example, the mesopore volume of sodium X molecular sieve is generally 0.032 cm 3 / g, and the mesopore volume of sodium Y-type molecular sieve is generally 0.04cm 3 / g, and the mesopore volume of sodium β-type molecular sieve is generally 0.016cm 3 / g or so.

[0038] According to a preferred embodiment of the present invention, the molecular sieve is an X-type molecular sieve, and the ratio of B acid / L acid of the catalyst at 200°C pyridine infrared is 1.2-3, and the ratio of B acid / L acid of the catalyst at 350°C pyridine infrared is 1-3.5. In the prior art, the ratio of B acid / L acid of solid acid catalyst is usually 0.5-1.

[0039] According to a preferred embodiment of the present invention, the molecular sieve is a Y-type molecular sieve, the catalyst has a 200°C pyridine infrared B acid / L acid ratio of 0.95-3.5, preferably 1.2-3.5, and a 350°C pyridine infrared B acid / L acid ratio of 0.95-3.5, preferably 1.5-3.5.

[0040] According to a preferred embodiment of the present invention, the molecular sieve is a β molecular sieve, and the ratio of pyridine infrared B acid / L acid of the catalyst at 200°C is 1-2, and the ratio of pyridine infrared B acid / L acid at 350°C is 1-2.

[0041] According to a preferred embodiment of the present invention, the preparation method of the solid acid catalyst comprises the following steps:

[0042] (1) mixing a sodium molecular sieve with a binder or its precursor, an auxiliary agent, an acid solution, and water to form a mixture, and then drying and calcining the mixture to obtain a calcined product;

[0043] (2) The calcined product obtained in step (1) is sequentially subjected to crystallization treatment, ammonium exchange, acid treatment and introduction of hydrogenation active components to obtain a solid acid catalyst.

[0044] The preparation method provided by the present invention expands the pores of the catalyst without destroying the catalyst skeleton, which can avoid the acid damage caused by the conventional acid-base treatment of the molecular sieve. The method provided by the present invention can achieve a balance between the pore structure and the acidity of the molecular sieve.

[0045] In the present invention, the types and properties of the sodium molecular sieve have been described in the foregoing content and will not be repeated here.

[0046] According to a preferred embodiment of the present invention, in step (1), the silicon-aluminum molar ratio of the sodium molecular sieve is 1-1000, preferably 1.5-500.

[0047] In the present invention, the types of adhesives have been described in the above content and will not be repeated here.

[0048] In the present invention, there is no particular limitation on the type of binder precursor in step (1). Preferably, the binder precursor is mainly aluminum salt, silicate, titanium salt and zirconium salt. For example, the aluminum salt may include pseudo-boehmite, aluminum chloride (AlCl3), aluminum sulfate (Al2(SO4)3), etc.; the silicate may include sodium silicate, potassium silicate, calcium silicate, etc.; the titanium salt may include titanium sulfate, titanium tetrachloride, etc.; the zirconium salt may include zirconium chloride, zirconium sulfate, etc.

[0049] According to a preferred embodiment of the present invention, in step (1), the amount of sodium molecular sieve and binder or its precursor is such that the weight ratio of sodium molecular sieve to binder in the catalyst is 90:10-20:80, preferably 90:10-50:50, calculated on a dry basis.

[0050] In the present invention, the acid solution and the auxiliary agent in step (1) can be selected from a wide range of types, and can be the acid solution and auxiliary agent conventionally defined in the art. For example, the acid solution is selected from at least one of hydrochloric acid solution, nitric acid solution, oxalic acid solution and citric acid solution, and the auxiliary agent is selected from at least one of sesbania powder, methylcellulose, polyether, polyvinyl alcohol, cyclodextrin and chitosan.

[0051] In the present invention, whether to add acid solution is considered according to the type of the binder or its precursor. If the binder is aluminum oxide or the binder precursor is aluminum salt, acid solution is added; if the binder is silicon dioxide, titanium oxide, zirconium oxide or the binder precursor is silicate, titanium salt or zirconium salt, acid solution may or may not be added; in the present invention, the auxiliary agent plays a role of lubrication and pore formation, and the auxiliary agent may or may not be added. When no auxiliary agent is added, the dried mixed molded product is directly calcined to obtain a calcined product; when a certain amount of auxiliary agent is added, the dried mixed molded product is first calcined, and then air-calcined to remove the auxiliary agent therein to obtain a calcined product.

[0052] According to a preferred embodiment of the present invention, in step (1), the amount of the acid solution and the auxiliary agent used is independently 0-5wt% of the total weight of the sodium molecular sieve and the binder on a dry basis.

[0053] In the present invention, there is no particular limitation on the amount of water, as long as the mixture including the sodium molecular sieve, the binder or its precursor, the acid solution and the auxiliary agent can be mixed uniformly. Preferably, the weight of water is in a ratio of (0.5-10) to the total weight of the dry basis of the other mixtures: 1, wherein the other mixtures refer to the mixture of the sodium molecular sieve, the binder or its precursor and the auxiliary agent.

[0054] According to a preferred embodiment of the present invention, in step (1), the drying conditions are such that the dry basis weight of the mixed molded product after drying is above 60 wt%.

[0055] According to a preferred embodiment of the present invention, in step (1), the calcination includes a first stage calcination and a second stage calcination. The advantage of adopting this preferred embodiment is to effectively remove organic matter such as lubricants added during the molding process and remove carbon deposits in the catalyst.

[0056] According to a preferred embodiment of the present invention, the conditions of the first stage roasting include: a roasting temperature of 450-650° C., a roasting time of 0.5-12 h, and a roasting pressure of 0-0.5 MPa.

[0057] According to a preferred embodiment of the present invention, the conditions of the second-stage roasting include: a roasting temperature of 500-600° C., a roasting time of 1-6 h, and a roasting pressure of normal pressure-0.3 MPa.

[0058] By calcining in the above preferred embodiment, the interaction between the molecular sieve and the binder is enhanced, the organic matter in the catalyst can be removed, and the damage to the catalyst skeleton structure can be reduced.

[0059] In the present invention, there is no particular limitation on the calcination atmosphere used for the first-stage calcination and the second-stage calcination. The existing calcination atmosphere in the art can be used, for example, it can be an air atmosphere, an ammonia water vapor atmosphere, a water vapor atmosphere, an N2 atmosphere, a He atmosphere or an Ar atmosphere. Preferably, the first-stage calcination is carried out in a water vapor or an ammonia water vapor atmosphere, and the second-stage calcination is carried out in an air atmosphere.

[0060] According to a preferred embodiment of the present invention, in step (2), the crystallization treatment comprises: subjecting the calcined product to a hydrothermal crystallization treatment in the presence of a template.

[0061] In the present invention, the template agent has a wide selection range. Preferably, the template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, hexadecyltrimethylammonium bromide and dodecyltrimethylammonium bromide.

[0062] According to a preferred embodiment of the present invention, the concentration of the template is 0.05-1.5 mol / L.

[0063] According to a preferred embodiment of the present invention, the conditions of the crystallization treatment include: temperature of 80-300° C., time of 1-24 h, and liquid-to-solid mass ratio of 0.05-10:1.

[0064] In the present invention, in step (2), the conditions for ammonium exchange are operations familiar to those skilled in the art, and the present invention has no special requirements for this. After the ammonium exchange, the Na2O content of the catalyst is reduced to less than 1% by weight, preferably less than 0.9% by weight. In the present invention, there is no special limitation on the type of ammonium solution in the ammonium exchange, for example, it can be at least one of ammonium nitrate solution, ammonium chloride solution and ammonium sulfate solution. In the present invention, preferably, the ammonium solution contains NH4 + The concentration is 0.05-8 mol / L. Preferably, in step (2), the conditions for the ammonium exchange include: a temperature of 50-150°C, a liquid-to-solid mass ratio of 5-50, and a time of 2-24 hours.

[0065] In the present invention, the method further comprises washing, filtering and drying the product after the ammonium exchange in sequence. The present invention has no particular limitation on the above operations, and existing methods in the art can be used.

[0066] In the present invention, the mesoporous volume of the catalyst can be effectively increased by acid treatment. Preferably, in step (2), the acid treatment conditions include: a temperature of 10-350° C. and a time of 0.5-36 h.

[0067] According to a preferred embodiment of the present invention, the acid used for the acid treatment is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, lactic acid, oxalic acid, fluorosilicic acid, hydrofluoric acid and ammonium fluorosilicate.

[0068] According to a preferred embodiment of the present invention, the concentration of the acids is independently 0.01-20 wt %.

[0069] In the present invention, in step (2), the types of the hydrogenation active components have been described in the above content and will not be repeated here.

[0070] According to a preferred embodiment of the present invention, the hydrogenation active component is provided by a solution containing a hydrogenation active component precursor, and the hydrogenation active component precursor is independently selected from the soluble salt of each hydrogenation active component, preferably selected from at least one of chloroplatinic acid, tetraamine platinum dichloride, tetraamine platinum nitrate, dinitrosodiammine platinum, tetraamine platinum acetate, palladium chloride, palladium nitrate, sodium chloropalladate and potassium chloropalladate, and further preferably selected from at least one of tetraamine platinum dichloride, tetraamine platinum nitrate, sodium chloropalladate and potassium chloropalladate.

[0071] According to a preferred embodiment of the present invention, in step (2), the amount of the hydrogenation active component is such that the content of the hydrogenation active component in the catalyst, calculated as an element, is 0.01-5wt%, preferably 0.1-1wt%, and more preferably 0.1-0.5wt%. The advantage of adopting this preferred embodiment is that the carbon deposits are completely degraded and the catalyst is completely regenerated.

[0072] In the present invention, the method for introducing the hydrogenation active component in step (2) can be a method conventionally defined in the art, such as an impregnation method, an atomic deposition method or a rotary evaporation method, preferably a rotary evaporation method, so that the hydrogenation active component is dispersed more evenly.

[0073] In the present invention, preferably, the method further comprises pre-treating the molecular sieve before mixing the sodium molecular sieve with other reaction raw materials, wherein the pre-treating method comprises: exchanging the molecular sieve with ammonium solution for 0.1-10h at 30-180°C, and then filtering and drying. Preferably, the ammonium solution contains NH4+ The concentration of ammonium is 0.05-8 mol / L. Preferably, the ammonium solution is selected from at least one of ammonium nitrate solution, ammonium chloride solution and ammonium sulfate solution.

[0074] According to a preferred embodiment of the present invention, the conditions of the alkylation reaction include: temperature of 100-280° C., pressure of 0.5-10 MPa, and feed flow rate of 10-3000 mL / (g·h).

[0075] In the present invention, the feed flow rate refers to the volume (mL) of isoparaffin and ethylene fed per hour per unit weight (g) of catalyst.

[0076] According to a preferred embodiment of the present invention, the isoalkane is a C3-C5 isoalkane, preferably isobutane.

[0077] According to a preferred embodiment of the present invention, the molar ratio of the isoparaffin to ethylene is 1-100:1, more preferably 5-50:1.

[0078] According to a preferred embodiment of the present invention, the alkylation reaction is carried out in a fixed bed reactor.

[0079] In the present invention, isoparaffin and ethylene are contacted with a solid acid catalyst to carry out an alkylation reaction according to the method of the present invention, which can increase the cycle life of the catalyst while ensuring the selectivity of the target product.

[0080] Unless otherwise specified, the pressures described in the present invention refer to gauge pressures.

[0081] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all the raw materials used can be obtained from commercial channels.

[0082] Y-type molecular sieve: unit cell constant is 2.466nm, silicon-aluminum molar ratio is 3, average particle size is 1μm, total acid content of pyridine infrared at 200℃ is 310μmol / g, mesopore volume is 0.042cm 3 / g, Sinopec Catalyst Co., Ltd.

[0083] X-type molecular sieve: unit cell constant is 2.485nm, silicon-aluminum molar ratio is 1.8, average particle size is 0.5μm, total acid content of pyridine infrared at 200℃ is 360μmol / g, and mesopore volume is 0.032cm 3 / g, Sinopec Catalyst Co., Ltd.

[0084] β-type molecular sieve: unit cell constant is 1.262nm, silicon-aluminum molar ratio is 50, average particle size is 10μm, total acid content of pyridine infrared at 200℃ is 560μmol / g, mesopore volume is 0.016cm 3 / g, Sinopec Catalyst Co., Ltd.

[0085] Pseudo-boehmite: average particle size is 100 μm, Sinopec Catalyst Co., Ltd.

[0086] In the following examples, X-ray diffraction (XRD) was used to determine the unit cell constant and crystallinity of the catalyst molecular sieve.

[0087] The mesoporous volume of the catalysts was measured using the BET method.

[0088] The pyridine adsorption infrared acid content of the solid acid catalyst is determined as follows: the instrument is a Bruker Tensor II Fourier transform infrared spectrometer. The test process is as follows: about 25 mg of the catalyst sample is pressed into a tablet at 20 MPa for 5 minutes, placed in an infrared spectrometer in-situ cell and sealed, and heated to 450°C at a rate of 10°C / min, and evacuated to 10 -6 Pa for 2h, cooled to room temperature, statically saturated adsorbed pyridine, then vacuumed, heated to 200℃ and 350℃ in steps to desorb the adsorbed pyridine, and measured the infrared spectra at the two temperatures and integrated. -1 The absorption peak at 1450cm -1 The absorption peak is attributed to the L acidic site.

[0089] C is the concentration of B acid or L acid (mmol / g), C B With C L The calculation formula is:

[0090] C B =1.88A B R 2 / W (Formula 1)

[0091] C L =1.42A L R 2 / W (Formula 2)

[0092] A is the integrated area of ​​the absorption peak of B acid or L acid;

[0093] R is the radius of the sample piece (cm);

[0094] W is the mass of the sample piece (mg).

[0095] The selectivity distribution of C5 and C6 of the obtained alkylate oil was determined by anglient-7890 gas chromatography analysis equipped with a high pressure injector (the chromatographic column was an HP-PONA 50 m×0.2 mm capillary column).

[0096] In the following examples and comparative examples, the selectivity distribution of C5 and C6 of the obtained alkylate oil was determined by anglient-7890 gas chromatography analysis (the chromatographic column is an HP-PONA 50m×0.2mm capillary column) equipped with a high-pressure injector. The detection idea and method for determining the one-way life of the solid acid catalyst are as follows: in normal reaction, the ethylene conversion rate is 100%. If ethylene is detected by gas chromatography, it indicates that the solid acid catalyst has begun to deactivate; when the ethylene conversion rate is 95%, the reaction time experienced by the solid acid catalyst is the one-way life of the solid acid catalyst.

[0097] Example 1

[0098] (1) At 80°C, use ammonium chloride solution (NH4 + The concentration of 3 mol / L) was used to carry out ammonium exchange on the NaY type molecular sieve for 2 hours, and then filtered and dried;

[0099] (2) mixing the ammonium-exchanged NH4NaY molecular sieve and pseudo-boehmite at a dry weight percentage of 9:1, adding 3wt% of sesbania powder and 1wt% of nitric acid (based on the total dry weight of the ammonium-exchanged Y molecular sieve and the binder), adding deionized water at a ratio of 1:1 of the weight of water to the total dry weight of other mixtures (a mixture of sodium molecular sieve, binder or its precursor and auxiliary agent), mixing well and extruding, drying at 120°C so that the dry weight of the mixed molded product after drying is 70wt%, and then steam-roasting at 600°C and a pressure of 0.15MPa for 2h, and air-roasting at 600°C for 4h, at a pressure of normal pressure;

[0100] (3) placing the obtained calcined product and 0.5 mol / L tetramethylammonium hydroxide solution in a mass ratio of 10:1 into a hydrothermal kettle, hydrothermally heating at 200° C. for 12 h, and washing, filtering and drying the obtained product;

[0101] (4) With ammonium chloride solution (NH4 + The concentration of the calcined product is 2 mol / L) with a liquid-solid mass ratio of 50:1, and ammonium exchange is performed at 80°C for 24 hours to reduce the content of Na2O in the calcined product to 0.5wt%, and then the calcined product is washed, filtered and dried;

[0102] (5) mixing the product obtained in step (4) with a hydrochloric acid solution (concentration of 5 wt%), subjecting the mixture to an acid treatment at 60° C. for 1 h, and then washing, filtering and drying;

[0103] (6) The product obtained in step (5) is subjected to rotary evaporation in a tetraammineplatinum dichloride solution to obtain catalyst Y-1.

[0104] Example 2

[0105] (1) At 100°C, use ammonium chloride solution (NH4 + The concentration of 2 mol / L) was used to ammonium exchange the NaY molecular sieve for 2 h, and then filtered and dried;

[0106] (2) mixing the ammonium-exchanged NH4NaY molecular sieve and pseudo-boehmite at a dry weight percentage of 50:50, adding 5% nitric acid, adding deionized water at a ratio of 1:1 of the weight of water to the total weight of the other mixture (a mixture of sodium molecular sieve, binder or its precursor and auxiliary agent), mixing evenly and extruding, drying at 120° C. so that the dry weight of the mixed molded product after drying is 70wt%, and then steam roasting at 450° C. for 2 h, the pressure is 0.3MPa, and air roasting at 500° C. for 3 h, the pressure is normal pressure;

[0107] (3) placing the obtained calcined product and 0.05 mol / L tetraethylammonium hydroxide solution in a mass ratio of 5:1 into a hydrothermal kettle, hydrothermally heating at 200° C. for 1 h, and washing, filtering and drying the obtained product;

[0108] (4) With ammonium chloride solution (NH4 + The concentration of the calcined product is 2 mol / L) with a liquid-solid mass ratio of 50:1, and ammonium exchange is performed at 120°C for 24 hours to reduce the content of Na2O in the calcined product to 0.5wt%, and then the calcined product is washed, filtered and dried;

[0109] (5) mixing the product obtained in step (4) with a hydrochloric acid solution (concentration of 5 wt%), subjecting the mixture to an acid treatment at 60° C. for 1 h, and then washing, filtering and drying;

[0110] (6) The product obtained in step (5) is subjected to rotary evaporation in a chloroplatinic acid solution to obtain catalyst Y-2.

[0111] Example 3

[0112] (1) At 60°C, use ammonium chloride solution (NH4 + The concentration of 2 mol / L) was used to carry out ammonium exchange on the Naβ molecular sieve for 10 hours, and then filtered and dried;

[0113] (2) mixing the ammonium-exchanged NH4Naβ molecular sieve and pseudo-boehmite at a dry weight percentage of 75:25, adding 5% sesbania powder and 2% nitric acid, adding deionized water at a ratio of 0.8:1 of the weight of water to the total weight of the other mixture (a mixture of sodium molecular sieve, binder or its precursor and auxiliary agent), mixing evenly and extruding, drying at 150°C so that the dry weight of the mixed molded product after drying is 70wt%, and then steam roasting at 550°C for 1h, the pressure is 0.1MPa, and air roasting at 550°C for 2h, the pressure is normal pressure;

[0114] (3) placing the obtained calcined product and 1 mol / L tetraethylammonium hydroxide solution in a mass ratio of 1:20 into a hydrothermal kettle, hydrothermalizing at 100° C. for 6 h, and washing, filtering and drying the obtained product;

[0115] (4) With ammonium chloride solution (NH4 + The concentration of the calcined product is 1 mol / L) with a liquid-solid mass ratio of 5:1, and ammonium exchange is performed at 60°C for 2 hours to reduce the content of Na2O in the calcined product to 0.1 wt%, and then the calcined product is washed, filtered and dried;

[0116] (5) mixing the product obtained in step (4) with an ammonium fluorosilicate solution (concentration: 5 wt%), subjecting the mixture to an acid treatment at 60° C. for 1 h, and then washing, filtering and drying the mixture;

[0117] (6) The product obtained in step (5) is subjected to rotary evaporation in a chloroplatinic acid solution to obtain catalyst β-1.

[0118] Example 4

[0119] The method of Example 1 is followed, except that the crystallization treatment is performed before calcination to obtain Y-3.

[0120] Example 5

[0121] Catalyst Y-4 was obtained by following the method of Example 1, except that deionized water was used to replace tetramethylammonium hydroxide during the hydrothermal treatment, and the hydrothermal temperature was 300° C.

[0122] Example 6

[0123] The method of Example 1 is followed, except that the concentration of hydrochloric acid in step (5) is 10 wt %, and the reaction is carried out at 150° C. for 24 h to obtain catalyst Y-5.

[0124] Example 7

[0125] The method of Example 1 is followed, except that type X molecular sieve is selected to obtain catalyst X-1.

[0126] Example 8

[0127] Catalyst Y-6 was obtained by following the method of Example 1, except that the hydrothermal crystallization treatment in step (3) was not performed.

[0128] Comparative Example 1

[0129] Catalyst DY-1 was prepared according to the method of Example 1 of patent application CN114054071A, and the acid content of the catalyst was determined according to the test method of Example 1 of the present invention.

[0130] Comparative Example 2

[0131] Catalyst DY-2 was obtained by following the method of Example 1 except that tetraammineplatinum dichloride solution was not introduced.

[0132] In the above examples and comparative examples, the content of hydrogenation active components in the catalyst is shown in Table 1, the structural parameters of the catalyst are shown in Table 2, and the acid content of the catalyst is shown in Table 3.

[0133] Table 1

[0134]

[0135]

[0136] Table 2

[0137]

[0138] Table 3

[0139]

[0140] Test Example 1

[0141] The solid acid catalysts prepared in the above-mentioned embodiment and comparative example were respectively used to carry out an alkylation reaction of isoparaffin and ethylene in a fixed bed reactor, and the reaction conditions were as follows: the molar ratio of isobutane to ethylene was 50, the reaction temperature was 280°C, the reaction atmosphere was a hydrogen-nitrogen mixture, and in terms of volume percentage, hydrogen:nitrogen=95:5, the reaction pressure was 3MPa, and the feed flow rate was 300mL / (g·h). When ethylene was detected in the product, the catalyst was considered to be deactivated, and the reaction time before the catalyst was deactivated was defined as the cycle life of the catalyst. The results of the alkylation reaction are shown in Table 4, in which C5 and C6 selectivities represent the average results within the cycle life.

[0142] Comparative test example 1

[0143] The catalyst of Example 1 was selected, except that in the alkylation reaction, the reaction atmosphere was pure nitrogen. The results of the alkylation reaction are shown in Table 4.

[0144] Among them, selectivity refers to the proportion of a certain component in alkylation gasoline. The selectivity is defined as

[0145] s n选择性 =A Cn ×100% (Formula 3)

[0146] In the formula, s n A is the integrated area ratio of butene in the gas chromatogram of hydrocarbons with carbon number n at a certain time; Sn It is the integrated area ratio of hydrocarbons with carbon number n in alkylate gasoline in the gas chromatogram.

[0147] Table 4

[0148] Catalyst No. Lifespan (h) <![CDATA[C5 Selectivity (%)]]> <![CDATA[C6 selectivity (%)]]> Test Example 1 Y-1 86 67.5 24.9 Test Example 1 Y-2 73 61.8 30.1 Test Example 1 β-1 70 64.2 23.5 Test Example 1 Y-3 67 54.6 33.7 Test Example 1 Y-4 64 48.8 40.1 Test Example 1 Y-5 59 45.5 42.7 Test Example 1 X-1 43 36.8 50.9 Test Example 1 Y-6 12 43.7 44.5 Test Example 1 DY-2 52 51.8 35.2 Comparative test example 1 Y-1 47 60.7 30.4

[0149] It can be seen from Table 4 above that the reaction life of the catalyst prepared by the method provided by the present invention is not affected compared with the catalyst prepared by the traditional method, and the reaction cycle of the catalyst can be greatly improved under hydrogen reaction conditions, thereby improving the service life of the catalyst.

[0150] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An alkylation method, characterized in that: The method comprises: in the presence of a hydrogen-containing atmosphere and a solid acid catalyst, carrying out an alkylation reaction on isoparaffin and ethylene; wherein the concentration of hydrogen in the hydrogen-containing atmosphere is 1-100 volume percent; the solid acid catalyst comprises a molecular sieve, a binder and a hydrogenation active component, based on the dry weight of the catalyst, the content of the molecular sieve is 20-90wt%, the content of the binder is 5-79.99wt%, and the content of the hydrogenation active component in terms of elements is 0.01-5wt%; the 200°C pyridine infrared total acidity of the catalyst is increased by 30-110% compared with the 200°C pyridine infrared total acidity of the molecular sieve; and the mesopore volume of the catalyst is increased by 70-215% compared with the mesopore volume of the molecular sieve.

2. The method according to claim 1, wherein: Based on the dry weight of the catalyst, the content of the molecular sieve is 25-84wt%, the content of the binder is 15-75wt%, and the content of the hydrogenation active component in terms of element is 0.1-1wt%; And / or, the total pyridine infrared acidity of the catalyst at 200°C is increased by 52-80% compared with the total pyridine infrared acidity of the molecular sieve at 200°C; And / or, the mesopore volume of the catalyst is increased by 110-215% compared with the mesopore volume of the molecular sieve.

3. The method according to claim 1 or 2, wherein: The molecular sieve is at least one of X-type, Y-type and β-type molecular sieves, preferably Y-type molecular sieve; and / or, the binder is selected from at least one of alumina, silica, titania, kaolin and montmorillonite, preferably at least one of alumina, silica and titania; And / or, the hydrogenation active component is selected from at least one of Pt, Pd, Ru and Ir, preferably Pt and / or Pd, and more preferably Pt.

4. The method according to any one of claims 1 to 3, wherein: The molecular sieve is an X-type molecular sieve, the unit cell constant of the catalyst is 2.46-2.485 nm, the total acidity of pyridine infrared at 200°C is greater than 360 μmol / g, preferably the total acidity of pyridine infrared at 200°C is 430-540 μmol / g, and the mesopore volume is 0.048-0.106 cm 3 / g; And / or, the molecular sieve is a Y-type molecular sieve, the unit cell constant of the catalyst is 2.441-2.466 nm, the total acidity of pyridine infrared at 200°C is greater than 310 μmol / g, preferably the total acidity of pyridine infrared at 200°C is 372-465 μmol / g, and the mesopore volume is 0.07-0.128 cm 3 / g; And / or, the molecular sieve is a β molecular sieve, the unit cell constant of the catalyst is 1.249-1.262 nm, the total acidity of pyridine infrared at 200°C is greater than 560 μmol / g, preferably the total acidity of pyridine infrared at 200°C is 670-840 μmol / g, and the mesopore volume is 0.024-0.051 cm 3 / g.

5. The method according to any one of claims 1 to 4, wherein: The molecular sieve is an X-type molecular sieve, and the ratio of pyridine infrared B acid / L acid of the catalyst at 200°C is 1.2-3, and the ratio of pyridine infrared B acid / L acid at 350°C is 1-3.5; And / or, the molecular sieve is a Y-type molecular sieve, and the ratio of pyridine infrared B acid / L acid of the catalyst at 200°C is 0.95-3.5, and the ratio of pyridine infrared B acid / L acid at 350°C is 0.95-3.5; And / or, the molecular sieve is a β molecular sieve, and the ratio of pyridine infrared B acid / L acid of the catalyst at 200°C is 1-2, and the ratio of pyridine infrared B acid / L acid at 350°C is 1-2.

6. The method according to any one of claims 1 to 5, wherein: The preparation method of the solid acid catalyst comprises the following steps: (1) mixing a sodium molecular sieve with a binder or its precursor, an auxiliary agent, an acid solution, and water to form a mixture, and then drying and calcining the mixture to obtain a calcined product; (2) The calcined product obtained in step (1) is sequentially subjected to crystallization treatment, ammonium exchange, acid treatment and introduction of hydrogenation active components to obtain a solid acid catalyst.

7. The method according to claim 6, wherein: In step (1), the amount of sodium molecular sieve and binder or its precursor is such that the weight ratio of sodium molecular sieve to binder in the catalyst is 90:10-20:80, preferably 90:10-50:50, calculated on a dry basis.

8. The method according to claim 6, wherein: In step (1), the amount of the acid solution and the auxiliary agent is independently 0-5wt% of the total weight of the sodium molecular sieve and the binder on a dry basis; Preferably, in step (1), the drying conditions are such that the dry basis weight of the mixed molding after drying is above 60wt%; Preferably, in step (1), the roasting includes a first stage roasting and a second stage roasting; Preferably, the conditions of the first stage roasting include: roasting temperature of 450-650°C, roasting time of 0.5-12h, roasting pressure of 0-0.5MPa; Preferably, the conditions of the second-stage roasting include: a roasting temperature of 500-600° C., a roasting time of 1-6 h, and a roasting pressure of normal pressure-0.3 MPa.

9. The method according to claim 6, wherein: In step (2), the crystallization treatment comprises: subjecting the calcined product to a hydrothermal crystallization treatment in the presence of a template; Preferably, the template is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, hexadecyltrimethylammonium bromide and dodecyltrimethylammonium bromide; Preferably, the concentration of the template is 0.05-1.5 mol / L; Preferably, in step (2), the conditions for the crystallization treatment include: temperature of 80-300° C., time of 1-24 h, and liquid-to-solid mass ratio of 0.05-10:

1.

10. The method according to claim 6, wherein: In step (2), the conditions for the ammonium exchange include: a temperature of 50-150° C., a liquid-to-solid mass ratio of 5-50, and a time of 2-24 h; And / or, in step (2), the acid treatment conditions include: temperature of 10-350° C., time of 0.5-36 h; And / or, the acid used for the acid treatment is at least one selected from hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, lactic acid, oxalic acid, fluorosilicic acid, hydrofluoric acid and ammonium fluorosilicate; and / or, the acid concentration is 0.1-20wt%; And / or, the hydrogenation active component is provided by a solution containing a hydrogenation active component precursor, and the hydrogenation active component precursor is independently selected from a soluble salt of each hydrogenation active component, preferably at least one selected from chloroplatinic acid, tetraamine platinum dichloride, tetraamine platinum nitrate, dinitrosodiammine platinum, tetraamine platinum acetate, palladium chloride, palladium nitrate, sodium chloropalladate and potassium chloropalladate, and more preferably at least one selected from tetraamine platinum dichloride, tetraamine platinum nitrate, sodium chloropalladate and potassium chloropalladate; And / or, in step (2), the amount of the hydrogenation active component used is such that the content of the hydrogenation active component in the catalyst, calculated as the element, based on the dry weight of the catalyst, is 0.01-5 wt%.

11. The method according to any one of claims 1 to 10, wherein: The conditions of the alkylation reaction include: temperature of 100-280° C., pressure of 0.5-10 MPa, and feed flow rate of 10-3000 mL / (g·h); Preferably, the isoalkane is a C3-C5 isoalkane, more preferably isobutane; Preferably, the molar ratio of the isoparaffin to ethylene is 1-100:1, more preferably 5-50:1.

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