CN112391195B

CN112391195B - Method for removing olefin from aromatic hydrocarbon raw material

Info

Publication number: CN112391195B
Application number: CN201910760580.7A
Authority: CN
Inventors: 胥明; 高焕新; 魏一伦
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2022-04-05
Anticipated expiration: 2039-08-16
Also published as: CN112391195A

Abstract

The invention relates to the field of olefin reduction, and discloses a method for removing olefin from an aromatic hydrocarbon raw material, which comprises the following steps: under the alkylation reaction condition, an aromatic hydrocarbon raw material is contacted with a catalyst, wherein the aromatic hydrocarbon raw material contains olefin and alkyl substituted aromatic hydrocarbon, and the content of ethyl substituted aromatic hydrocarbon is not higher than 20 wt% based on the total amount of the alkyl substituted aromatic hydrocarbon. The method avoids the use of clay on one hand and can ensure the service life of the catalyst on the other hand.

Description

Method for removing olefin from aromatic hydrocarbon raw material

Technical Field

The invention relates to the field of olefin reduction, in particular to a method for removing olefin from an aromatic hydrocarbon raw material.

Background

Unsaturated hydrocarbons such as mono-olefins, multi-olefins and styrenic species, which are typically contained in aromatic hydrocarbon feedstocks, can lead to undesirable side reactions in downstream processes. Therefore, these unsaturated hydrocarbons should be removed by reaction before the aromatic feedstock is used in other processes.

It is possible to remove unsaturated hydrocarbons from aromatic feedstocks industrially by means of a hydrotreating process. The method has high activity and stability, and can partially convert olefin in aromatic hydrocarbon raw material into alkyl aromatic compound. However, the hydrotreating process usually employs a noble metal catalyst, and typical catalysts are disclosed in patent documents CN104342201B, CN106268797B, CN104014337B, CN 1282733C. In addition, for a wide-component raw material of aromatic hydrocarbons containing benzene, toluene and xylene at the same time, it is difficult to fully consider the hydrogenation reaction depth, and particularly, aromatic hydrocarbons with carbon nine or more form low-boiling-point toluene and other aromatic hydrocarbons after hydrogenation, so that the loss of aromatic hydrocarbon products is large. In addition, the hydrogenation reaction has higher requirements on equipment, higher device cost, harsh reaction conditions and certain aromatic hydrocarbon loss rate. Therefore, there is a need in the industry for a more efficient and less expensive process.

The use of clay and molecular sieves in the processing of aromatic hydrocarbon feedstocks has been reported. In the case of clays, the service life is usually only a few weeks, or even less, and the exploitation of clays can cause permanent damage to the environment. In addition, the deactivated argil containing aromatic hydrocarbon is very harmful to human health, cannot be regenerated and recycled, and can only be treated by landfill, thus causing serious secondary pollution to the environment. With the increasing awareness of environmental protection, the problem is more and more concerned by the nation and the people, and the olefin removal technology capable of solving the problem is urgently needed by the production enterprises.

The molecular sieve has longer service life than the clay, is renewable, and can replace the clay under the condition of not changing the device. In view of the above advantages of molecular sieve catalysts, a number of de-olefm catalysts prepared with molecular sieves as the major component have been disclosed. CN1618932A describes a catalyst for catalytically refining and reforming aromatic oil under non-hydrogenation conditions, which is prepared by extruding kaolin, aluminum oxide and beta molecular sieve into strips, but the catalyst still has the defect of short service life, and the service life is less than one month. CN102220158A discloses a supported catalyst comprising at least one element or oxide selected from Ni, Mo, W or Zr, at least one element or oxide selected from Ti, Cu or Al and at least one rare earth element or oxide. In the initial period of operation, the disclosed catalyst has good performance, but the service life of the catalyst is still not ideal, and the weight space velocity is 0.3h^-1The one-way service life of the catalyst can only reach four months under the condition of (2). CN107754846A reports a method for modifying molecular sieve by adding rear main group element, which interacts with lanthanide and alkali element to achieve better effect, but this method has the disadvantages of relatively complex preparation process and more steps.

In addition, the olefin reducing molecular sieve catalyst which is industrially applied at present cannot be used alone generally, and still needs to be matched with clay for use. Therefore, a molecular sieve catalyst with better reactivity and stability without clay pretreatment is needed.

Disclosure of Invention

The invention aims to solve the problems that the olefin-reducing molecular sieve catalyst needs to be matched with argil for use and the stability of the molecular sieve catalyst needs to be further improved in the prior art, and provides a method for removing olefin from an aromatic hydrocarbon raw material.

In order to achieve the above object, the present invention provides a method for removing olefins from an aromatic hydrocarbon feedstock, the method comprising: under the alkylation reaction condition, an aromatic hydrocarbon raw material is contacted with a catalyst, wherein the aromatic hydrocarbon raw material contains olefin and alkyl substituted aromatic hydrocarbon, and the content of ethyl substituted aromatic hydrocarbon is not higher than 20 wt% based on the total amount of the alkyl substituted aromatic hydrocarbon.

Preferably, the ethyl-substituted aromatic hydrocarbon content is not higher than 15% by weight, preferably 0-14% by weight, based on the total amount of alkyl-substituted aromatic hydrocarbons.

Preferably, the methyl-substituted aromatic hydrocarbon is present in an amount of not less than 75% by weight, based on the total amount of alkyl-substituted aromatic hydrocarbons.

Preferably, the content of propyl-substituted aromatic hydrocarbons is not higher than 5% by weight, based on the total amount of alkyl-substituted aromatic hydrocarbons.

Preferably, the catalyst comprises a molecular sieve and optionally a binder, preferably the molecular sieve is a MWW molecular sieve; further preferably, the preparation method of the MWW molecular sieve comprises:

(1) mixing a silicon source, an aluminum source, an alkali source, a template agent and water, wherein the mixing is carried out at 0-15 ℃;

(2) carrying out hydrothermal treatment on the mixture obtained in the step (1) under a hydrothermal crystallization condition;

(3) roasting the solid product obtained in the step (2);

wherein the molar ratio of the silicon source, the aluminum source, the alkali source, the template agent and the water is 10: 0.2-2: 5-30: 0.5-10: 20-300, preferably 10: 0.5-1.5: 10-20: 0.5-5: 30-300, more preferably 10: 0.6-0.9: 14-18: 1-3:40-200, wherein the silicon source is SiO₂Calculated by Al as the aluminum source₂O₃Calculated as OH as alkali source^-And (6) counting.

In the research process, the inventor of the invention finds that the service life of the catalyst is closely related to the content of the ethyl-substituted aromatic hydrocarbon in the alkyl-substituted aromatic hydrocarbon in the aromatic hydrocarbon raw material, and the stability of the catalyst can be improved by controlling the content of the ethyl-substituted aromatic hydrocarbon in the alkyl-substituted aromatic hydrocarbon, so that the longer service life of the catalyst is ensured. In the process of further research, the inventor finds that controlling the content of methyl-substituted aromatic hydrocarbon in alkyl-substituted aromatic hydrocarbon in the aromatic hydrocarbon raw material to be not less than 75 wt% and the content of propyl-substituted aromatic hydrocarbon in the aromatic hydrocarbon raw material to be not more than 5 wt% is more beneficial to further prolonging the service life of the catalyst. The inventor of the present invention has continued research and found that, when the MWW molecular sieve with a large acid content is prepared by mixing a silicon source, an aluminum source, an alkali source, a template agent and water at 0-15 ℃, and then performing hydrothermal treatment and calcination, the MWW molecular sieve is used for treating alkyl-substituted aromatic hydrocarbons, when the content of ethyl-substituted aromatic hydrocarbons is not higher than 20 wt%, olefins in the aromatic hydrocarbon raw material can be removed more favorably, and the catalyst has a longer service life. The results of the examples show that the olefin conversion rate is still more than 70% and the aromatic hydrocarbon loss rate is below 0.43% after 10000h of reaction by adopting the method provided by the invention.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a method for removing olefin from an aromatic hydrocarbon raw material, which comprises the following steps: contacting an aromatic hydrocarbon feedstock with a catalyst under alkylation reaction conditions, wherein the aromatic hydrocarbon feedstock comprises olefins and alkyl-substituted aromatic hydrocarbons, and wherein the ethyl-substituted aromatic hydrocarbons are present in an amount of no greater than 20 wt.%, preferably no greater than 15 wt.%, and more preferably from 0 to 14 wt.%, based on the total amount of alkyl-substituted aromatic hydrocarbons.

The stability of the catalyst can be improved by controlling the content of the ethyl-substituted aromatic hydrocarbon in the alkyl-substituted aromatic hydrocarbon, so that the longer service life of the catalyst is ensured.

According to the invention, the alkyl-substituted aromatic hydrocarbon is preferably an alkyl-substituted monocyclic aromatic hydrocarbon. Specifically, the alkyl-substituted aromatic hydrocarbon is a liquid alkyl-substituted aromatic hydrocarbon.

According to the present invention, preferably, the alkyl-substituted aromatic hydrocarbon comprises a methyl-substituted aromatic hydrocarbon, an optionally ethyl-substituted aromatic hydrocarbon and an optionally propyl-substituted aromatic hydrocarbon.

According to the invention, the olefins comprise mono-olefins and/or di-olefins, preferably the mono-olefins content of the olefins is not less than 90% by weight, preferably 95-99.9% by weight. By adopting the preferred embodiment, the side reaction in the subsequent alkylation process is avoided, the yield and the quality of the alkylbenzene are further improved, and the service life of the catalyst is further prolonged. Specifically, the monoolefin may be an alkene, or may be an aromatic olefin.

Where the alkyl-substituted aromatic hydrocarbon has an ethyl-substituted aromatic hydrocarbon content of greater than 20 wt.% in the aromatic hydrocarbon feedstock, the process may further comprise adjusting the ethyl-substituted aromatic hydrocarbon content of the alkyl-substituted aromatic hydrocarbon to not greater than 20 wt.%. The adjustment may be to remove part of the ethyl-substituted aromatic hydrocarbon, or to introduce a methyl-substituted aromatic hydrocarbon and/or a propyl-substituted aromatic hydrocarbon into the raw material to reduce the ethyl-substituted aromatic hydrocarbon, which is not particularly limited in the present invention. Preferably, the adjusting method includes: methyl-substituted aromatic hydrocarbons are introduced into an aromatic hydrocarbon feedstock.

According to a preferred embodiment of the present invention, the content of methyl-substituted aromatic hydrocarbons is not less than 75% by weight, preferably 85-99.9% by weight, based on the total amount of alkyl-substituted aromatic hydrocarbons.

According to a preferred embodiment of the present invention, the content of propyl-substituted aromatic hydrocarbons is not higher than 5% by weight, preferably 0-2% by weight, based on the total amount of alkyl-substituted aromatic hydrocarbons.

The inventor of the invention finds that controlling the content of the ethyl substituted aromatic hydrocarbon, the content of the methyl substituted aromatic hydrocarbon and the content of the propyl substituted aromatic hydrocarbon in the alkyl substituted aromatic hydrocarbon is more beneficial to further prolonging the service life of the catalyst.

According to a preferred embodiment of the present invention, the aromatic hydrocarbon feedstock has a gum content of not more than 200mg/100mL, preferably a gum content of not more than 120mg/100mL, more preferably not more than 60mg/100mL, for example 0-60mg/100 mL.

According to the present invention, the gum refers to solid matter in the feedstock, typically saturated monocyclic aromatic hydrocarbons and/or polycyclic aromatic hydrocarbons of C18 or greater, unless otherwise specified. In the reaction process, polycyclic aromatic hydrocarbon is not easy to generate ring-opening reaction and coking, which seriously affects the product quality, yield and the service life of the catalyst and is not beneficial to the alkylation reaction. The colloid content is measured by the method of GB/T8019-2008, when the boiling point of the raw material is close to that of the gasoline, the standard of the GB/T8019-2008 about the gasoline is adopted for measuring; when the boiling point of the raw material is close to that of the diesel oil, the standard of GB/T8019-2008 about the diesel oil is adopted for measurement.

The method provided by the invention preferably also comprises the step of pretreating the aromatic hydrocarbon raw material so that the colloid content in the raw material is not more than 200mg/100 mL. The method of pretreatment is not particularly limited in the present invention, as long as the colloid content in the aromatic hydrocarbon feedstock can be reduced to not more than 200mg/100 mL. For example, membrane filtration and distillation may be used to reduce the gums in the aromatic feedstock, and the specific procedures are known to those skilled in the art and are not described herein.

According to the present invention, preferably, the content of olefins in the aromatic hydrocarbon feedstock is between 0.1 and 10 wt.%, and the content of alkyl-substituted aromatic hydrocarbons is between 90 and 99.9 wt.%; preferably, the olefin content is from 0.1 to 5 wt%, and the alkyl-substituted aromatic hydrocarbon content is from 95 to 99.9 wt%; further preferably, the olefin content is from 0.1 to 3% by weight and the alkyl-substituted aromatic hydrocarbon content is from 97 to 99.9% by weight.

According to the present invention, the aromatic hydrocarbon feedstock may contain, in addition to gums, olefins, and alkyl-substituted aromatic hydrocarbons, saturated hydrocarbons, benzene, and the like.

According to the method for removing olefins from an aromatic hydrocarbon feedstock provided by the present invention, if the contents of methyl-substituted aromatic hydrocarbon, ethyl-substituted aromatic hydrocarbon and propyl-substituted aromatic hydrocarbon in the alkyl-substituted aromatic hydrocarbon are not within the above ranges, the method may further specifically include adjusting the amounts of methyl-substituted aromatic hydrocarbon, ethyl-substituted aromatic hydrocarbon and propyl-substituted aromatic hydrocarbon in the alkyl-substituted aromatic hydrocarbon so as to satisfy the above requirements. The specific adjustment method of the present invention is not particularly limited, and for example, when the content of the methyl-substituted aromatic hydrocarbon is small, the methyl-substituted aromatic hydrocarbon may be introduced into the raw material to increase the content of the methyl-substituted aromatic hydrocarbon.

In the present invention, the content of olefins, alkyl-substituted aromatics, methyl-substituted aromatics, ethyl-substituted aromatics and propyl-substituted aromatics in the aromatic hydrocarbon feedstock can be measured by a method of color quality analysis.

In the present invention, the methyl-substituted aromatic hydrocarbon refers to a methyl-based aromatic hydrocarbon in which a methyl group is connected to a benzene ring of an aromatic hydrocarbon, the ethyl-substituted aromatic hydrocarbon refers to an ethyl-based aromatic hydrocarbon in which an ethyl group is connected to a benzene ring of an aromatic hydrocarbon, and the propyl-substituted aromatic hydrocarbon refers to a propyl-based aromatic hydrocarbon in which a propyl group is connected to a benzene ring of an aromatic hydrocarbon. When at least two of methyl, ethyl and propyl groups are connected to the benzene ring of the aromatic hydrocarbon, the alkyl-substituted aromatic hydrocarbon is counted as an alkyl-substituted aromatic hydrocarbon with a high carbon atom number, that is, when the methyl and ethyl groups are simultaneously connected to the benzene ring of the aromatic hydrocarbon, the alkyl-substituted aromatic hydrocarbon is counted as an ethyl-substituted aromatic hydrocarbon, when the ethyl and propyl groups are simultaneously connected to the benzene ring of the aromatic hydrocarbon, the alkyl-substituted aromatic hydrocarbon is counted as a propyl-substituted aromatic hydrocarbon, and when the methyl, ethyl and propyl groups are simultaneously connected to the benzene ring of the aromatic hydrocarbon, the alkyl-substituted aromatic hydrocarbon is counted as a propyl-substituted aromatic hydrocarbon.

According to the present invention, 1 to 4 methyl groups may be attached to the benzene ring of the methyl-substituted aromatic hydrocarbon, and preferably, the methyl-substituted aromatic hydrocarbon is at least one selected from the group consisting of toluene, p-xylene, m-xylene, o-xylene, mesitylene, pseudocumene and durene.

According to the present invention, 1 or 2 ethyl groups may be attached to the benzene ring of the ethyl-substituted aromatic hydrocarbon, and preferably, the ethyl-substituted aromatic hydrocarbon is selected from at least one of ethylbenzene, m-diethylbenzene, o-diethylbenzene, and p-diethylbenzene.

According to the present invention, in the propyl-substituted aromatic hydrocarbon, the propyl group bonded to the benzene ring of the aromatic hydrocarbon may be an n-propyl group or an isopropyl group. Preferably, the phenyl ring of the propyl-substituted aromatic hydrocarbon has attached 1 or 2, preferably 1, propyl groups.

According to a preferred embodiment of the present invention, the propyl-substituted arene is n-propylbenzene and/or isopropylbenzene.

According to the invention, in particular, the catalyst may contain a molecular sieve and optionally a binder, preferably a molecular sieve and a binder. The binder may bind the molecular sieve particles together, and the binder may be an amorphous binder material. Preferably, the binder is selected from at least one of alumina, silica, kaolin, bentonite, montmorillonite and sepiolite, and is further preferably alumina.

The content of the binder and the molecular sieve in the catalyst is selected in a wide range, and preferably, the content of the molecular sieve is 55-90 wt%, and more preferably 70-80 wt% based on the total amount of the catalyst; the content of the binder is 10 to 45 wt%, and further 20 to 30 wt%.

The present invention is not particularly limited to the method for preparing the catalyst, and preferably, the method for preparing the catalyst comprises:

a) extruding the molecular sieve and a binder and/or a precursor thereof into strips for molding to obtain a molding material;

b) and drying and roasting the formed product.

In the preparation process of the catalyst, a binder can be added, a precursor of the binder can also be added, and the binder and the precursor of the binder can also be added simultaneously.

In the present invention, the binder precursor refers to a substance that can be converted into the binder by a subsequent firing step, and a person skilled in the art knows which binder precursor to select, knowing the kind of binder.

The present invention is not particularly limited to the manner of the extrusion molding in step a), and the extrusion molding includes: mixing the molecular sieve, the binder and/or a precursor thereof, water and an optional peptizing agent, and then extruding and molding the obtained mixture. The extrusion molding can be carried out in an extrusion molding machine.

According to the invention, preferably, a peptizing agent is added in the extrusion molding process. The peptizing agent may be at least one of inorganic acids, such as nitric acid.

The amount of the peptizing agent and water used in the present invention is selected from a wide range, for example, the amount of the peptizing agent may be 0.1 to 10 parts by weight and the amount of water may be 10 to 60 parts by weight, relative to 100 parts by weight of the molecular sieve and the binder and/or the precursor thereof.

The shape of the molded product is not particularly limited in the present invention, and may be appropriately selected according to actual needs, and may be, for example, a strip shape.

According to the catalyst provided by the invention, the drying and roasting in the step b) can be carried out according to the conventional technical means in the field, and the drying can be carried out at 50-180 ℃. The conditions for the firing may include: the temperature is 400-600 ℃, and the time is 2-100 h.

According to the invention, the preparation process of the catalyst can also comprise an ammonium exchange process, wherein the ammonium exchange process can be carried out before the extrusion molding in the step a), and specifically, the molecular sieve can be subjected to ammonium exchange to obtain a hydrogen type molecular sieve; the ammonium exchange process can also be carried out after the drying in the step b) and before the roasting, and specifically, the solid product obtained by the drying is subjected to ammonium exchange and then the roasting is carried out. The present invention is not particularly limited with respect to the specific operation and conditions of the ammonium exchange, and may be carried out according to the means conventional in the art, for example, the step of ammonium exchange may include: the molecular sieve or the solid product obtained by drying is contacted with ammonium nitrate solution. The ammonium exchange may be carried out a plurality of times, for example 2 to 5 times. The time for each ammonium exchange can be 0.5-5 h.

According to a preferred embodiment of the present invention, the molecular sieve has a twelve-membered ring channel structure, and further preferably, the molecular sieve is at least one of a beta molecular sieve, a Y-type molecular sieve and an MWW molecular sieve. The preferred molecular sieves are more suitable for treating the aromatic hydrocarbon feedstock of the present invention and are more conducive to improving the stability and activity of the catalyst.

The invention has wider selection range of the Si/Al molar ratio of the molecular sieve, and preferably, SiO₂/Al₂O₃In a molar ratio of 20 to 100: 1, more preferably 20 to 50: 1. the silica to alumina molar ratio of the molecular sieve can be determined by elemental analysis.

According to a more preferred embodiment of the invention, the molecular sieve is a MWW molecular sieve; preferably, the MWW molecular sieve has an acid amount of not less than 0.9mg NH₃Per 100mg, more preferably not less than 1mg NH₃Per 100mg, more preferably not less than 1.2mg NH₃Per 100mg, more preferably 1.3-2.5mg NH₃And/100 mg. The adoption of the preferred embodiment is more beneficial to further improving the catalytic activity of the catalyst and further prolonging the service life of the catalyst.

Specifically, the acid content of the molecular sieve is measured by an ammonia adsorption method, and the acid content test method of the molecular sieve comprises the following steps: roasting the molecular sieve at 500 ℃ for 1h in air atmosphere, reducing the temperature to 25 ℃ and weighing, wherein the weight is recorded as a; then placing the calcined molecular sieve in a mixed gas of ammonia gas and nitrogen gas with the ammonia gas concentration of 5 vol% for 30min, then purging for 1h by using nitrogen gas, weighing, and recording the weight as b; the acid content of the molecular sieve is calculated according to the following formula (1):

the acid amount of the molecular sieve is (b-a)/a × 100% formula (1).

The acid content of MWW molecular sieves disclosed in the prior art is generally less than 0.9mg NH₃/100mg。

According to the present invention, in particular, the MWW molecular sieve has a monolayer lamellar structure. In the present invention, the monolayer lamellar structure means that the ratio of the smallest dimension (referred to as thickness) to the smallest dimension (referred to as length) of the three-dimensional dimensions of the molecular sieve is not more than 1/3. In the present invention, the structure of the MWW molecular sieve can be characterized by Scanning Electron Microscopy (SEM).

The MWW molecular sieve with the structure and the composition can further prolong the service life and the activity of the molecular sieve catalyst, and the preparation method of the MWW molecular sieve is not particularly limited. Preferably, the preparation method of the MWW molecular sieve comprises the following steps:

(3) roasting the solid product obtained in the step (2);

wherein the molar ratio of the silicon source, the aluminum source, the alkali source, the template agent and the water is 10: 0.2-2: 5-30: 0.5-10: 20-300, wherein the silicon source is SiO₂Calculated by Al as the aluminum source₂O₃Calculated as OH as alkali source^-And (6) counting.

According to a preferred embodiment of the invention, the mixing in step (1) is carried out at a temperature of 0 to 10 ℃, preferably at a temperature of 2 to 10 ℃. The MWW molecular sieve prepared by the preferred embodiment has higher acid content, and the catalyst prepared by the obtained molecular sieve has higher activity and longer service life in the alkylation process.

In the mixing process of step (1), the order of adding the silicon source, the aluminum source, the alkali source, the template and the water is not particularly limited, as long as the mixing is carried out at 0-15 ℃. In the invention, the silicon source, the aluminum source, the alkali source, the template and the water can be directly mixed together, or at least two of the silicon source, the aluminum source, the alkali source, the template and the water can be mixed in advance, and then other residual materials are added.

According to the present invention, the adding amount of the aluminum source, the alkali source, the template and the water can be selected according to the amount of the silicon source, and preferably, the molar ratio of the silicon source, the aluminum source, the alkali source, the template and the water is 10: 0.5-1.5: 10-20: 0.5-5: 30-300 parts of; further preferably, the molar ratio of the silicon source, the aluminum source, the alkali source, the template agent and the water is 10: 0.6-0.9: 14-18: 1-3: 40-200.

According to the present invention, the silicon source may be an organic silicon source and/or an inorganic silicon source, preferably an inorganic silicon source. The source of the organic silicon may be a silicate including, but not limited to, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate. Preferably, the inorganic silicon source is at least one of silica, silica sol and water glass, and more preferably, silica sol and/or water glass. The silica sol can be obtained commercially. The invention is used for SiO in silica sol₂The content of (b) is not particularly limited, and may be, for example, 15 to 45% by weight.

According to the present invention, preferably, the aluminum source is an alkaline aluminum source, and further preferably, the aluminum source is at least one selected from the group consisting of metal aluminates, metal metaaluminates, aluminum hydroxide, aluminum powder, and aluminum oxide. The metal of the metal aluminate and the metal meta-aluminate are each independently preferably an alkali metal, and the alkali metal may be selected from at least one of Li, Na, K, and Rb, preferably Na.

According to the present invention, the alkali source is used for providing the alkalinity of the synthesis raw material, and the present invention has a wide range of selection of the kind of the alkali source, and preferably, the alkali source is an inorganic alkali, more preferably at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and calcium hydroxide, still more preferably sodium hydroxide and/or potassium hydroxide, and still more preferably sodium hydroxide.

According to the present invention, preferably, the template is at least one selected from the group consisting of ethylenediamine, hexamethylenediamine, cyclohexylamine, hexamethyleneimine, heptamethyleneimine, pyridine, hexahydropyridine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine and octadecylamine, more preferably hexamethyleneimine.

According to the present invention, the mixing time in step (1) is selected from a wide range, based on the uniform mixing of the silicon source, the aluminum source, the alkali source, the template and the water, and is preferably 0.1 to 10 hours, and more preferably 0.5 to 3 hours. According to a particular embodiment of the invention, the mixing of step (1) is carried out under stirring conditions. The stirring speed is not particularly limited in the present invention, and can be appropriately selected by those skilled in the art according to the actual situation.

According to the present invention, preferably, the hydrothermal crystallization conditions of step (2) include: the temperature is 100-200 ℃, and preferably is 120-190 ℃; the time is 5-200h, preferably 30-120 h. Specifically, the hydrothermal treatment may be performed under autogenous pressure conditions under closed conditions.

The mode of obtaining the solid product in the present invention is not particularly limited, and generally, the production method further includes: and (3) filtering and drying a product obtained by the hydrothermal treatment in the step (2) to obtain the solid product. The drying may be carried out at 50-180 ℃.

According to a preferred embodiment of the present invention, the firing conditions in step (3) include: the temperature is 400-600 ℃, and the time is 5-100 h.

The present invention provides a wide selection of alkylation reaction conditions to enable alkylation of olefins with alkyl substituted aromatic hydrocarbons, preferably the alkylation reaction conditions result in an olefin conversion of greater than 70%, preferably greater than 80%, and more preferably greater than 90%.

According to the method for removing olefins from an aromatic hydrocarbon feedstock provided by the present invention, preferably, the alkylation reaction conditions include: the temperature is preferably from 100 ℃ to 300 ℃, more preferably from 140 ℃ to 220 ℃, even more preferably from 150 ℃ to 180 ℃, and even more preferably from 170 ℃ to 180 ℃; the pressure is 0.5-5MPa, preferably 1-3MPa in terms of gauge pressure; the mass space velocity of the aromatic hydrocarbon raw material is 0.1-50h^-1Preferably 0.1 to 10h^-1More preferably 0.5 to 5 hours^-1。

The method provided by the invention ensures that the catalyst has high stability, and the duration of the alkylation reaction can be maintained to be more than 1 year under the optimal condition.

The present invention will be described in detail below by way of examples.

Example 1

Method for removing olefin from aromatic hydrocarbon raw material in fixationThe method is carried out in a bed reactor, the loading amount of a catalyst is 1g, and under alkylation reaction conditions, catalysts A, B and C are respectively in contact reaction with raw materials 1 and 2, wherein the alkylation reaction conditions comprise: the temperature is 180 ℃, the reaction pressure is 2.0MPa according to gauge pressure, and the mass space velocity of the raw material is 3.0h^-1。

The preparation method of the catalyst A comprises the following steps: a50 g sample of commercially available MCM-22 powder (commercially available from Nanjing Xiancheng nanomaterial science and technology Co., Ltd., trade name XFF09, SiO)₂/Al₂O₃27) was mixed with 15g of alumina, then 18g of 5% by weight nitric acid was added and kneaded, then strand-formed into a phi 1.6 × 2 mm strand on a strand-forming machine, dried at 120 ℃, exchanged with 5% by mass ammonium nitrate until 99.9% by weight of Na in the solid product was removed, and then calcined at 550 ℃ for 10 hours.

The preparation method of the catalyst B comprises the following steps: a sample of 55g of commercially available Beta powder (commercially available from Nanjing Xiancheng nanomaterial science and technology Co., Ltd., trade name XFF13, SiO)₂/Al₂O₃40) with 20g of alumina, then 20g of 5 wt.% nitric acid is added and kneaded, then the mixture is extruded on a rod extruder to form a rod of phi 1.6 x 2 mm, dried at 120 ℃, exchanged with 5 wt.% ammonium nitrate to remove 99.9 wt.% Na in the solid product, and then calcined at 550 ℃ for 10 hours.

The preparation method of the catalyst C comprises the following steps: 60g of a sample of commercially available Y zeolite powder (commercially available from Nanjing Xiancheng nanomaterial science and technology Co., Ltd., trade name XFF10, SiO)₂/Al₂O₃At a molar ratio of 5.3) with 20g of alumina, then 18g of 5 wt.% nitric acid was added and kneaded, then the mixture was extruded into a rod-shaped form of phi 1.6 × 2 mm on a rod extruder, dried at 120 ℃, exchanged with 5 wt.% ammonium nitrate to remove 99.9 wt.% Na in the solid product, and then calcined at 550 ℃ for 10 hours.

The compositions of feed 1 and feed 2 are listed in table 1.

The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

Alkylation stability tests were conducted on catalyst a, specifically, catalyst a and feed 1 were subjected to contact reaction under the above alkylation conditions, and the results of olefin conversion and aromatics loss for 20h, 100h, 500h, 2000h, 5000h and 10000h of reaction are shown in table 4.

Comparative example 1

The procedure of example 1 was followed except that feed 1 was replaced with feed 3 by reacting catalysts A, B and C in contact with feed 3, respectively, the composition of feed 3 being as shown in Table 1. The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

Example 2

Diluting the raw material 3 by using xylene, filtering after dilution, and reducing the colloid content to 90mg/100ml to obtain a raw material 4, wherein the content of methyl-substituted aromatic hydrocarbon is 85.2 wt%, the content of ethyl-substituted aromatic hydrocarbon is 12.9 wt%, and the content of propyl-substituted aromatic hydrocarbon is 1.9 wt% based on the total amount of the alkyl-substituted aromatic hydrocarbon. The procedure of example 1 was followed, except that the starting material 1 was replaced with the starting material 4, namely, the catalysts A, B and C were respectively contact-reacted with the starting material 4. The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

Example 3

The procedure of example 1 was followed except that feed 1 was replaced with feed 5 by reacting catalysts A, B and C in contact with feed 5, respectively, the composition of feed 5 being as shown in Table 1. The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

Example 4

The procedure of example 1 was followed, except that the catalysts D were used to contact and react with the starting materials 1 to 5, respectively. The preparation method of the catalyst D comprises the following steps:

(1) stirring and mixing silica sol, sodium aluminate, NaOH, hexamethyleneimine and water for 3 hours at the temperature of 2 ℃ to prepare a silicon source, an aluminum source, an alkali source, a template agent and water with the molar ratio of 10: 0.8: 18: 2.2: 150, wherein the silicon source is SiO₂Calculated by Al as the aluminum source₂O₃Calculated as OH as alkali source^-And (6) counting.

(2) The mixture is crystallized for 65h at 150 ℃, and then filtered and dried (120 ℃) to obtain a solid product.

(3) And (3) carrying out ammonium exchange on the solid product and an ammonium nitrate solution with the mass concentration of 5% until 99.9 wt% of Na in the solid product is removed.

(4) And roasting the product obtained by ammonium exchange at 480 ℃ for 24h to obtain the MWW molecular sieve. The molecular sieve has a monolayer lamellar structure and the acid content of the molecular sieve is 1.3mg NH according to the characterization of a Scanning Electron Microscope (SEM)₃/100mg。

(5) Taking the molecular sieve and the alumina binder according to the ratio of 8: 2, nitric acid and water with a mass concentration of 2.5%, and 63 parts by weight of an aqueous nitric acid solution per 100 parts by weight of the molecular sieve and the alumina. The resulting mixture was formed into a bar having a length of Φ 1.6 × 2 mm in a plodder. The resulting strands were dried at 100 ℃ for 6h and then calcined at 500 ℃ for 25h to give catalyst D. The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

Example 5

The procedure of example 1 was followed except that the catalysts E were used to contact and react with the starting materials 1 to 5, respectively. The preparation of catalyst E was carried out in accordance with the preparation of catalyst D, except that in step (1), silica sol, sodium aluminate, NaOH, hexamethyleneimine and water were mixed at 27 ℃. The acid content of the prepared molecular sieve is 0.8mg NH₃And/100 mg. The results of the 24h reaction are shown in Table 2 and the results of the 240h reaction are shown in Table 3.

TABLE 1

	Starting materials 1	Raw material 2	Raw material 3	Starting Material 5
					Gum content, mg/100mL	115	45	370	140
Olefin content, wt.%	1.2	0.7	2.1	1.3
					Content of monoolefin in the olefin,% by weight	97.5	98.1	94.2	95.4
Content of alkyl-substituted aromatic hydrocarbons,% by weight	96.9	99.1	92.4	91.7
					Content of methyl-substituted aromatic hydrocarbons,% by weight	78.5	87.2	70.4	75.0
Aryl substituted by ethylContent of hydrocarbons,% by weight	18.1	11.1	25.8	17.2
					Content of propyl-substituted aromatic hydrocarbons,% by weight	3.4	1.7	3.8	7.8

Note: in table 1, the olefin content and the alkyl-substituted aromatic hydrocarbon content are based on the aromatic hydrocarbon feedstock, and the methyl-substituted aromatic hydrocarbon, the ethyl-substituted aromatic hydrocarbon, and the propyl-substituted aromatic hydrocarbon content are based on the alkyl-substituted aromatic hydrocarbon.

In table 1, the raw materials 1 to 5 are aromatic hydrocarbon raw materials from Shanghai Gaoqian petrochemical industry, and the methyl-substituted aromatic hydrocarbons in the raw materials 1 to 5 are each independently selected from at least one of toluene, p-xylene, m-xylene, o-xylene, mesitylene, pseudocumene and durene; the ethyl-substituted aromatic hydrocarbons in the raw materials 1-5 are respectively and independently selected from at least one of ethylbenzene, m-diethylbenzene, o-diethylbenzene and p-diethylbenzene; the propyl-substituted aromatic hydrocarbons in feedstocks 1-5 are each independently n-propylbenzene and/or cumene.

TABLE 2 reaction 24h olefin conversion

TABLE 3 reaction 240h olefin conversion

Name of catalyst	Starting materials 1	Raw material 2	Raw material 3	Raw material 4	Starting Material 5
						A	95.5％	96.1％	66.9％	95.8％	67.8％
B	92.9％	95.9％	51.6％	95.1％	56.4％
						C	93.1％	95.6％	56.8％	94.9％	61.1％
D	97.0％	98.1％	70.5％	97.5％	71.8％
						E	95.9％	96.6％	68.8％	96.3％	70.0％

TABLE 4 olefin conversion and aromatics loss for catalyst A with feed 1 at different reaction times

Reaction time	20h	100h	500h	2000h	5000h	10000h
							Olefin conversion,%	99.5	96.5	91.1	84.8	78.7	72.4
Aromatic hydrocarbon loss rate%	0.43	0.42	0.40	0.39	0.38	0.38

Wherein, the aromatic hydrocarbon loss rate calculation formula is as follows:

S_{aromatic hydrocarbons}＝(M¹ _{Aromatic hydrocarbons}-M² _{Aromatic hydrocarbons})/M¹ _{Aromatic hydrocarbons}×100％

Wherein S is_{Aromatic hydrocarbons}Is the loss rate of aromatic hydrocarbons; m¹ _{Aromatic hydrocarbons}The mass of aromatic hydrocarbon in the raw material; m² _{Aromatic hydrocarbons}Is the quality of aromatic hydrocarbon in the reaction product after the reaction.

As can be seen from the data in tables 2 to 4, the method for removing the olefin from the aromatic hydrocarbon raw material provided by the invention has the advantages of high reaction stability and low aromatic hydrocarbon loss rate. After 10000h of reaction, the conversion rate of olefin is still more than 70 percent, and the loss rate of aromatic hydrocarbon is below 0.43 percent.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A process for removing olefins from an aromatic hydrocarbon feedstock, the process comprising: under the condition of alkylation reaction, an aromatic hydrocarbon raw material is contacted with a catalyst, wherein the aromatic hydrocarbon raw material contains olefin and alkyl substituted aromatic hydrocarbon, the content of the ethyl substituted aromatic hydrocarbon is not higher than 20 wt% and the content of the methyl substituted aromatic hydrocarbon is not lower than 75 wt% based on the total amount of the alkyl substituted aromatic hydrocarbon.

2. The process of claim 1 wherein the ethyl substituted aromatic hydrocarbon content is no greater than 15 wt%.

3. The process of claim 1 wherein the ethyl substituted aromatic hydrocarbon content is from 0 to 14 weight percent.

4. The process of claim 1, wherein the ethyl-substituted aromatic hydrocarbon is selected from at least one of ethylbenzene, m-diethylbenzene, o-diethylbenzene, and p-diethylbenzene.

5. The process of claim 1 wherein the methyl-substituted aromatic hydrocarbon is present in an amount of from 85 to 99.9 weight percent, based on the total amount of alkyl-substituted aromatic hydrocarbon.

6. The method of claim 1, wherein the methyl-substituted aromatic hydrocarbon has 1-4 methyl groups attached to the benzene ring.

7. The method of claim 1, wherein the methyl-substituted aromatic hydrocarbon is selected from at least one of toluene, p-xylene, m-xylene, o-xylene, mesitylene, pseudocumene, and durene.

8. The process of claim 1, wherein the propyl-substituted aromatic hydrocarbon is present in an amount of no greater than 5 wt.%, based on the total amount of alkyl-substituted aromatic hydrocarbon.

9. The process of claim 1, wherein the propyl-substituted aromatic hydrocarbon is present in an amount of 0 to 2 wt.%, based on the total amount of alkyl-substituted aromatic hydrocarbon.

10. The process of claim 8, wherein the propyl-substituted arene is n-propylbenzene and/or isopropylbenzene.

11. The process of any of claims 1-10, wherein the amount of mono-olefin in the olefin is not less than 90 wt.%.

12. The process of claim 11, wherein the amount of mono-olefins in the olefin is 95 to 99.9 wt.%.

13. The process of any one of claims 1-10, wherein the aromatic hydrocarbon feedstock has an olefin content of from 0.1 to 10 wt% and an alkyl-substituted aromatic hydrocarbon content of from 90 to 99.9 wt%.

14. The process of any one of claims 1-10, wherein the aromatic hydrocarbon feedstock has an olefin content of 0.1 to 5 wt% and an alkyl-substituted aromatic hydrocarbon content of 95 to 99.9 wt%.

15. The process of any one of claims 1-10, wherein the aromatic hydrocarbon feedstock has a gum content of no greater than 200mg/100 mL.

16. The process of claim 15, wherein the aromatic hydrocarbon feedstock has a gum content of no greater than 120mg/100 mL.

17. The process of claim 15, wherein the aromatic hydrocarbon feedstock has a gum content of no greater than 60mg/100 mL.

18. The process of any of claims 1-10, wherein the catalyst comprises a molecular sieve and optionally a binder; the molecular sieve has a twelve-membered ring channel structure.

19. The process of claim 18, wherein the molecular sieve is at least one of a beta molecular sieve, a Y-type molecular sieve, and an MWW molecular sieve.

20. The method of claim 18, wherein the binder is selected from at least one of alumina, silica, kaolin, bentonite, montmorillonite and sepiolite.

21. The process of claim 18, wherein the molecular sieve is a MWW molecular sieve.

22. The process of claim 21, wherein the MWW molecular sieve has an acid content of not less than 0.9mg NH₃/100mg；

The acid content of the MWW molecular sieve is measured by an ammonia adsorption method, and the acid content test method of the MWW molecular sieve comprises the following steps: roasting the molecular sieve at 500 ℃ for 1h in air atmosphere, reducing the temperature to 25 ℃ and weighing, wherein the weight is recorded as a; then placing the calcined molecular sieve in a mixed gas of ammonia gas and nitrogen gas with the ammonia gas concentration of 5 vol% for 30min, then purging for 1h by using nitrogen gas, weighing, and recording the weight as b; the acid content of the molecular sieve is calculated according to the following formula (1);

the acid amount of the molecular sieve is (b-a)/a × 100% formula (1).

23. The process of claim 22, wherein the MWW molecular sieve has an acid content of not less than 1mg NH₃/100mg。

24. The process of claim 22, wherein the MWW molecular sieve has an acid content of not less than 1.2mg NH₃/100mg。

25. The process of claim 22, wherein the MWW molecular sieve has an acid amount of 1.3-2.5mg NH₃/100mg。

26. The method of claim 21, wherein the MWW molecular sieve has a monolayer sheet-like structure.

27. The process of claim 21, wherein the process for preparing the MWW molecular sieve comprises:

(3) roasting the solid product obtained in the step (2);

28. The method of claim 27, wherein the molar ratio of the silicon source, the aluminum source, the alkali source, the templating agent, and the water is 10: 0.5-1.5: 10-20: 0.5-5: 30-300.

29. The method of claim 27, wherein the molar ratio of the silicon source, the aluminum source, the alkali source, the templating agent, and the water is 10: 0.6-0.9: 14-18: 1-3: 40-200.

30. The method of claim 27, wherein the mixing of step (1) is performed at 0-10 ℃.

31. The method of claim 30, wherein the mixing of step (1) is performed at 2-10 ℃.

32. The process of claim 27, wherein the mixing time of step (1) is 0.1-10 h.

33. The process of claim 27, wherein the mixing time of step (1) is 0.5-3 h.

34. The method of claim 27, wherein,

the silicon source is an inorganic silicon source;

the aluminum source is at least one selected from metal aluminate, metal meta-aluminate, aluminum hydroxide, aluminum powder and aluminum oxide;

the alkali source is inorganic alkali and is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and calcium hydroxide;

the template agent is at least one selected from ethylenediamine, hexamethylenediamine, cyclohexylamine, hexamethyleneimine, heptamethyleneimine, pyridine, hexahydropyridine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine and octadecylamine.

35. The method of claim 34, wherein the silicon source is at least one of silica, silica sol, and water glass.

36. The method of claim 34, wherein the silicon source is silica sol and/or water glass.

37. The method of claim 34, wherein the alkali source is sodium hydroxide and/or potassium hydroxide.

38. The method of claim 27, wherein the hydrothermal crystallization conditions of step (2) comprise: the temperature is 100-200 ℃; the time is 5-200 h.

39. The method of claim 27, wherein the hydrothermal crystallization conditions of step (2) comprise: the temperature is 120-190 ℃; the time is 30-120 h.

40. The method of claim 27, wherein,

the roasting condition in the step (3) comprises the following steps: the temperature is 400-600 ℃, and the time is 5-100 h.

41. The process of any of claims 1-10, wherein the alkylation reaction conditions result in an olefin conversion of greater than 70%.

42. The method of claim 41, wherein,

the alkylation reaction conditions result in an olefin conversion of greater than 80%.

43. The method of any one of claims 1-10,

the alkylation reaction conditions include: the temperature is 100-300 ℃, the pressure is 0.5-5MPa, and the mass space velocity of the aromatic hydrocarbon raw material is 0.1-50h^-1。

44. The process of any one of claims 1-10, wherein the alkylation reaction conditions comprise: the temperature is 140 ℃ and 220 ℃, the pressure is 1-3MPa in terms of gauge pressure, and the mass space velocity of the aromatic hydrocarbon raw material is 0.5-10h^-1。