System and method for producing aromatic hydrocarbon from oxygen-containing raw material

Abstract

The invention discloses a system and a method for producing aromatic hydrocarbon from an oxygen-containing raw material, and the system comprises a coupling reactor which comprises a light hydrocarbon production unit and an aromatic hydrocarbon production unit which are coaxially distributed in a partitioned manner, and a heat conduction interlayer is arranged between the light hydrocarbon production unit and the aromatic hydrocarbon production unit; the light hydrocarbon production unit and the aromatic hydrocarbon production unit can be communicated to realize material flow; the light hydrocarbon production unit is filled with a light hydrocarbon production catalyst and located on the outer side of the aromatic hydrocarbon production unit, and the aromatic hydrocarbon production unit is filled with an aromatic hydrocarbon production catalyst; the adsorption dehydration unit is arranged between communication pipelines of the light hydrocarbon production unit and the aromatic hydrocarbon production unit of the coupling reactor; a dry gas removal unit; the quenching unit and the aromatic hydrocarbon separation unit are sequentially communicated with a product outlet of the aromatic hydrocarbon production unit in series. By means of the arrangement mode of the system, efficient heat transfer can be guaranteed. The system is used for producing aromatic hydrocarbon from the oxygen-containing compound, the reaction temperature of an aromatic hydrocarbon production unit can be better maintained, efficient utilization of reaction heat is achieved, and the system has the advantages of being low in energy consumption, high in efficiency and the like.

Description

Technical Field

[0001] The invention relates to the technical field of chemical equipment and efficient utilization of chemical heat, and in particular to a system and method for producing aromatic hydrocarbons using oxygen-containing raw materials. Background Art

[0002] Efficient use of heat in chemical reactions is a critical step in the development of chemical equipment. For highly exothermic reaction units in heterogeneous reactions, energy needs to be quickly extracted and recovered to reduce hot spots, while for endothermic reaction units, a large amount of heat needs to be added to maintain the reaction temperature. The multi-step series coupling reaction process is a special type of reaction process. For example, in the production of aromatics and olefins, there are often multiple steps such as exothermic reactions and endothermic reactions. Therefore, it is necessary to use efficient coupling reactors to achieve efficient use of heat.

[0003] In recent years, continuous flow coupled reactors with heat exchange capabilities have attracted attention and been applied. CN112473612A discloses a novel continuous flow coupled reactor for rapid and strong exothermic reactions, including a reactor shell; a microstructure mixer and a large flux tubular reactor are arranged from top to bottom in the reactor shell, and the inlet of the large flux tubular reactor is connected to the outlet of the microstructure mixer; the microstructure mixer is used to efficiently mix and disperse the reaction materials, and can accurately control the temperature, and quickly lead the uniformly mixed reaction materials to the rear end large flux tubular reactor for reaction; the large flux tubular reactor has an inner heat exchange tube and an outer heat exchange jacket, which provide the heat exchange required for the reaction, and when performing large flux operation, ensure that the reactor has efficient mixing, mass transfer and heat transfer performance.

[0004] CN104496743A discloses a method for converting methanol to produce an aromatic mixture rich in benzene, toluene and xylene in a fixed bed reactor, which comprises loading a catalyst for converting methanol to produce light hydrocarbons and a catalyst for aromatization of light hydrocarbons in the same fixed bed reactor, wherein the lower layer is the catalyst for aromatization of light hydrocarbons, and the upper layer is the catalyst for converting methanol to produce light hydrocarbons to form a catalyst combination unit; methanol vapor is divided into several streams, one of which is mixed with circulating LPG and water vapor and enters the fixed bed reactor from a material inlet arranged at the top of the fixed bed reactor, and the rest of the methanol vapor enters the fixed bed reactor from a material inlet located on the side wall of the reactor, so as to obtain an aromatic mixture rich in BTX.

[0005] The above literature reports on the production of aromatics have problems such as poor adaptability of process conditions to oxygen-containing feedstocks, low yield of aromatic products, and long-term stability and high energy consumption due to the presence of a large amount of water. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems of high energy consumption, poor adaptability and low product yield in the prior art, and to provide a system for producing aromatics from oxygen-containing raw materials, which can better maintain the reaction temperature of the production unit, achieve efficient utilization of reaction heat, and has the advantages of low energy consumption and high efficiency.

[0007] A first aspect of the present invention provides a system for producing aromatic hydrocarbons from oxygen-containing feedstocks, the system comprising:

[0008] Coupled reactor: including a light hydrocarbon production unit and an aromatics production unit coaxially distributed in different zones, a heat-conducting interlayer is provided between the light hydrocarbon production unit and the aromatics production unit, and the light hydrocarbon production unit and the aromatics production unit can be connected to realize material flow; the light hydrocarbon production unit is loaded with a light hydrocarbon production catalyst and is located outside the aromatics production unit, and the aromatics production unit is loaded with an aromatics production catalyst;

[0009] and an adsorption dehydration unit disposed between the light hydrocarbon production unit and the aromatics production unit connecting pipelines of the coupled reactor; and a dry gas removal unit;

[0010] A quenching unit and an aromatics separation unit are connected in series with the product outlet of the aromatics production unit.

[0011] In a second aspect, the present invention provides a method for producing aromatic hydrocarbons from oxygen-containing feedstocks. The method is carried out in the system of the present invention, and the method comprises:

[0012] (1) introducing an oxygen-containing feedstock into a light hydrocarbon production unit to obtain a product mainly containing carbon-containing compounds, dry gas and water;

[0013] (2) The carbon-containing compounds are sent to an aromatics production unit through a pipeline to obtain a product mainly containing aromatics and non-aromatics.

[0014] The arrangement of the system of the present invention can ensure efficient heat transfer. The system of the present invention is used to produce aromatics from oxygen-containing compounds, which can better maintain the reaction temperature of the aromatics production unit, achieve efficient use of reaction heat, and has the advantages of low energy consumption and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a cross-sectional schematic diagram of a reactor operation process according to one embodiment of the present invention;

[0016] Figure 2 It is a method of feeding and discharging raw materials and products of a light hydrocarbon production unit according to one embodiment of the present invention;

[0017] Figure 3 It is the way of entering and exiting the raw materials and products of the aromatics production unit according to one embodiment of the present invention;

[0018] Figure 4The figure is a schematic flow diagram of a method for producing aromatic hydrocarbons from oxygen-containing feedstocks according to one embodiment of the present invention. DETAILED DESCRIPTION

[0019] 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.

[0020] In the present invention, unless otherwise specified, directional words such as "up, down, left, right", "inside, outside", "far, near" used refer to the structural relationship as shown in the accompanying drawings.

[0021] The present invention provides a system for producing aromatic hydrocarbons from oxygen-containing feedstocks, such as Figure 4 As shown, the system includes: a coupled reactor;

[0022] and an adsorption dehydration unit ② and a dry gas removal unit ③ disposed between the light hydrocarbon production unit ① and the aromatics production unit ④ connecting pipelines of the coupled reactor;

[0023] A quenching unit ⑤ and an aromatics separation unit ⑥ are sequentially connected in series with the product outlet of the aromatics production unit; the coupled reactor is the coupled reactor described in the present invention.

[0024] The coupled reactor of the present invention includes a plurality of functional reaction zones coaxially distributed in partitions, and each functional reaction zone is connected as needed to realize material flow, and an intermediate layer is arranged between two adjacent functional reaction zones, and each intermediate layer is an insulating layer and / or a heat-conducting layer.

[0025] According to a preferred embodiment of the present invention, Figure 1 As shown, the reactor includes a light hydrocarbon production unit and an aromatics production unit distributed in coaxial partitions, a heat-conducting interlayer is arranged between the light hydrocarbon production unit and the aromatics production unit, and the light hydrocarbon production unit and the aromatics production unit can be connected to realize material flow; the light hydrocarbon production unit is filled with a light hydrocarbon production catalyst and is located outside the aromatics production unit, and the aromatics production unit is filled with an aromatics production catalyst.

[0026] The arrangement of the system of the present invention can ensure efficient heat transfer. The system of the present invention is used to produce aromatics from oxygen-containing compounds, which can better maintain the reaction temperature of the aromatics production unit, achieve efficient use of reaction heat, and has the advantages of low energy consumption and high efficiency.

[0027] According to a preferred embodiment of the present invention, the feedstock inlet of the light hydrocarbon production unit and the feedstock inlet of the aromatic hydrocarbon production unit are arranged so that the axial flow direction of the feedstock of the aromatic hydrocarbon production unit is opposite to the axial flow direction of the feedstock of the light hydrocarbon production unit.

[0028] According to a preferred embodiment of the present invention, Figure 2 As shown, the raw material inlet of the light hydrocarbon production unit is one end of the outer wall, and the product outlet is the other end of the outer wall. Preferably, the raw material inlet and the product outlet are centrally symmetrically distributed.

[0029] According to a preferred embodiment of the present invention, Figure 3 As shown, the raw material inlet of the aromatics production unit is one axial end of the unit, and the product outlet is the other axial end. Preferably, the raw material inlet and the product outlet are centrally symmetrically distributed.

[0030] In the present invention, the light hydrocarbon production unit is connected with the aromatic hydrocarbon production unit as needed, and the connection method can be determined according to the reaction requirements. According to a preferred embodiment of the present invention, the product outlet of the light hydrocarbon production unit is connected with the raw material inlet of the aromatic hydrocarbon production unit through a pipeline.

[0031] According to a preferred embodiment of the present invention, a flow guide distribution plate is installed at the inlet end of the aromatics production unit.

[0032] According to a preferred embodiment of the present invention, the heat conducting medium of the heat conducting interlayer is heat conducting oil and / or heat conducting molten salt.

[0033] The arrangement of the system of the present invention can ensure efficient heat transfer. The system of the present invention is used to produce aromatics from oxygen-containing compounds, which can better maintain the reaction temperature of the aromatics production unit, achieve efficient use of reaction heat, and has the advantages of low energy consumption and high efficiency.

[0034] The device for producing aromatics from oxygen-containing raw materials of the present invention utilizes a new system formed by several units. The system is used to produce aromatics from oxygen-containing raw materials and has the advantages of strong adaptability to oxygen-containing raw materials, high aromatics yield, good long-term stability and low energy consumption.

[0035] According to a preferred embodiment of the present invention, a heat-conducting interlayer is provided between the light hydrocarbon production unit and the aromatic hydrocarbon production unit.

[0036] According to a preferred embodiment of the present invention, the feedstock inlet of the light hydrocarbon production unit and the feedstock inlet of the aromatic hydrocarbon production unit are arranged so that the axial flow direction of the feedstock of the aromatic hydrocarbon production unit is opposite to the axial flow direction of the feedstock of the light hydrocarbon production unit.

[0037] According to a preferred embodiment of the present invention, the feed inlet of the light hydrocarbon production unit is one end of the outer wall, and the product outlet is the other end of the outer wall. Preferably, the feed inlet and the product outlet are centrally symmetrically distributed.

[0038] According to a preferred embodiment of the present invention, the feed inlet of the aromatics production unit is one axial end of the unit, and the product outlet is the other axial end. Preferably, the feed inlet and the product outlet are centrally symmetrically distributed.

[0039] According to a preferred embodiment of the present invention, the adsorption dehydration unit ② comprises a top inlet and a bottom outlet.

[0040] According to a preferred embodiment of the present invention, the dry gas removal unit ③ comprises a bottom inlet and a top outlet.

[0041] According to a preferred embodiment of the present invention, the quenching unit ⑤ comprises a bottom inlet and a top outlet.

[0042] According to a preferred embodiment of the present invention, the aromatic separation unit ⑥ comprises a top non-aromatic hydrocarbon stream outlet and a bottom aromatic hydrocarbon stream outlet.

[0043] The present invention provides a method for producing aromatic hydrocarbons, such as Figure 4 As shown, the method is carried out in the system described in the present invention, and the method comprises:

[0044] (1) passing the raw material into a light hydrocarbon production unit to obtain a product mainly containing carbon-containing compounds, dry gas and water;

[0045] (2) The carbon-containing compounds are sent to an aromatics production unit through a pipeline to obtain a product mainly containing aromatics and non-aromatics.

[0046] In the present invention, there is no special requirement for the raw materials for preparing aromatic hydrocarbons, and the commonly used raw materials for preparing aromatic hydrocarbons can be used in the present invention. For the present invention, the raw materials for preparing aromatic hydrocarbons are preferably selected from one or more of alcohols, ethers, aldehydes, ketones and naphtha.

[0047] In the present invention, there are no special requirements for the conditions of the light hydrocarbon production unit. According to a preferred embodiment of the present invention, preferably, the operating conditions of the light hydrocarbon production unit include: a reaction temperature of 320-630°C, preferably 370-550°C, for example, 370°C, 390°C, 410°C, 430°C, 450°C, 470°C, 490°C, 510°C, 530°C, 550°C, but the present invention is not limited to this range.

[0048] According to a preferred embodiment of the present invention, preferably, the operating conditions of the light hydrocarbon production unit include: a pressure of 0.05-3.2MPa, for example, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 1.0MPa, 1.2MPa, 1.4MPa, etc. can all achieve the purpose of the present invention, but the present invention is not limited to this scope.

[0049] In the present invention, the catalyst of each unit is not the design focus of the present invention. The selection of the catalyst can be selected according to the prior art. According to a preferred embodiment of the present invention, preferably, the catalyst of the light hydrocarbon production unit contains 50-90% by weight of molecular sieve and 10-50% by weight of alumina. The molecular sieve can be, for example, a ZSM-5 molecular sieve, but the present invention is not limited to the catalyst, and the scope of the present invention is not limited thereto.

[0050] In the present invention, there are no special requirements for the conditions of the aromatics production unit. According to a preferred embodiment of the present invention, the operating conditions of the aromatics production unit include: a reaction temperature of 430-580°C, preferably 450-530°C, for example, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C. In the present invention, the aromatics production unit does not require external heat supply at all, and the specific temperature conditions are controlled according to the heat release and external heat extraction of the light hydrocarbon production unit.

[0051] In the present invention, there is no special requirement for the catalyst of the aromatics production unit. For the present invention, the catalyst of the aromatics production unit preferably includes 0.1-5% by weight of transition metal oxide, 30-85% by weight of zeolite molecular sieve and 15-70% by weight of binder. In the present invention, there is no special requirement for the types of transition metal oxide, zeolite molecular sieve and binder, and the commonly used ones can achieve the purpose of the present invention.

[0052] According to a preferred embodiment of the present invention, the zeolite molecular sieve is selected from ten-membered ring molecular sieves.

[0053] According to a preferred embodiment of the present invention, the binder is selected from one or more of aluminum oxide, silicon oxide and titanium oxide.

[0054] In the present invention, the catalyst of the aromatics production unit can adopt the catalyst of CN201510141378. In the embodiments of the present invention, the catalyst of Example 1 of CN201510141378 (CN 106140272A) is used as an example to illustrate the advantages of the present invention, but the scope of the present invention is not limited thereby.

[0055] According to a preferred embodiment of the present invention, the operating conditions of the aromatics production unit include: a pressure of 0.1-2.8 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 1.0 MPa, 1.2 MPa, 1.4 MPa, 1.7 MPa, 2.0 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, etc. can all achieve the purpose of the present invention, but the present invention is not limited to this scope.

[0056] According to a preferred embodiment of the present invention, the product containing carbon compounds, dry gas and water passes through an adsorption dehydration unit and a dry gas removal unit in sequence to remove water and dry gas, and then is sent to an aromatics production unit through a pipeline to obtain a product mainly containing aromatics and non-aromatics.

[0057] According to a preferred embodiment of the present invention, the product of the aromatics production unit is successively passed through a quenching unit and an aromatics separation unit to separate two streams of materials, one of which is a non-aromatics stream and the other is an aromatics stream, wherein the aromatics stream is used as the final product. In the present invention, the adsorption dehydration unit is mainly used for adsorption dehydration, and there are no special requirements for the adsorption dehydration conditions and the type of adsorbent. According to a preferred embodiment of the present invention, the operating conditions of the adsorption dehydration unit include: an adsorption temperature of 10-150°C, preferably 20-125°C; an adsorption pressure of 0.1-2.8MPa, preferably 0.15-2.5Mpa; the adsorbent is selected from one or more of molecular sieves, alumina, calcium chloride and silica gel, but the scope of the present invention is not limited thereby.

[0058] In the embodiment of the present invention, the adsorption temperature is 40±5° C., the adsorption pressure is 0.50±0.05 MPa, and the adsorbent is 3A molecular sieve as an exemplary illustration of the advantages of the present invention, but the present invention is not limited thereto.

[0059] In the present invention, the dry gas removal unit is used to dehydrate dry gas, and there is no special requirement for its removal conditions. According to a preferred embodiment of the present invention, the operating conditions of the dry gas removal unit include: an operating temperature of 5-180°C, preferably 10-160°C; an operating pressure of 0.1-2.5MPa, preferably 0.15-2.2Mpa. In the embodiment of the present invention, the operating temperature is 30±5°C; the operating pressure is 0.40±0.05MPa; as an exemplary illustration of the advantages of the present invention, but the present invention is not limited thereto.

[0060] In the present invention, the quenching unit and the aromatic separation unit are mainly used for product separation. There are no special requirements for the quenching conditions and the aromatic separation conditions. According to a preferred embodiment of the present invention, the operating conditions of the quenching unit include: the outlet temperature is 5-80°C, preferably 10-65°C; the operating pressure is 0.1-2.2MPa, preferably 0.15-2.0MPa. In the embodiment of the present invention, the outlet temperature is 50±5°C; the operating pressure is 0.30±0.05MPa; as an exemplary illustration of the advantages of the present invention, but the present invention is not limited thereto.

[0061] According to a preferred embodiment of the present invention, the operating conditions of the aromatic separation unit include: an outlet temperature of 0-70°C, preferably 5-65°C; an operating pressure of 0.1-2.0MPa, preferably 0.15-2.0MPa. In the embodiment of the present invention, the outlet temperature is 30±5°C; the operating pressure is 0.40±0.05MPa; as an example to illustrate the advantages of the present invention, but the present invention is not limited thereto.

[0062] The present invention is further described below by way of examples. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0063] The following examples are based on Figure 4 The process shown is carried out.

[0064] The coupled reactor comprises a light hydrocarbon production unit and an aromatic hydrocarbon production unit coaxially distributed in different zones, a heat-conducting interlayer is arranged between the light hydrocarbon production unit and the aromatic hydrocarbon production unit, and the light hydrocarbon production unit and the aromatic hydrocarbon production unit can be connected to realize material flow; the light hydrocarbon production unit is loaded with a light hydrocarbon production catalyst and is located outside the aromatic hydrocarbon production unit, and the aromatic hydrocarbon production unit is loaded with an aromatic hydrocarbon production catalyst;

[0065] The raw material inlet of the light hydrocarbon production unit is at one end of the outer wall, and the product outlet is at the other end of the outer wall, and the raw material inlet and the product outlet are centrally symmetrically distributed;

[0066] The raw material inlet of the aromatics production unit is one end of the unit in the axial direction, and the product outlet is the other end of the axial direction, and the raw material inlet and the product outlet are centrally symmetrically distributed;

[0067] The product outlet of the light hydrocarbon production unit is connected to the raw material inlet of the aromatic hydrocarbon production unit through a pipeline;

[0068] The heat-conducting medium of the heat-conducting interlayer is a heat-conducting molten salt;

[0069] The adsorption dehydration unit ② has a top inlet and a bottom outlet;

[0070] The dry gas removal unit ③ has a bottom inlet and a top outlet;

[0071] The quenching unit ⑤ has a bottom inlet and a top outlet;

[0072] The aromatic separation unit ⑥ comprises a top non-aromatic hydrocarbon stream outlet and a bottom aromatic hydrocarbon stream outlet;

[0073] The following examples and comparative examples:

[0074] The operating conditions of the adsorption dehydration unit include: adsorption temperature is 40±5°C; adsorption pressure is 0.50±0.05MPa, and the adsorbent is 3A molecular sieve.

[0075] The operating conditions of the dry gas removal unit include: operating temperature of 30±5°C; operating pressure of 0.40±0.05MPa.

[0076] The operating conditions of the quenching unit include: outlet temperature is 50±5°C; operating pressure is 0.30±0.05MPa.

[0077] The operating conditions of the aromatic separation unit include: outlet temperature of 30±5°C; operating pressure of 0.40±0.05MPa.

[0078] In the present invention, the carbon-based yield of aromatic hydrocarbons is calculated as follows: carbon-based yield of aromatic hydrocarbons = total weight of aromatic hydrocarbons in the product / (total weight of raw materials - total weight of product water).

[0079] In the present invention, unless otherwise specified, each content is by weight.

[0080] Example 1

[0081] The coupled reactor of the present invention is used, methanol is used as raw material, the raw material is introduced into a light hydrocarbon production unit, and a commercial MTP catalyst (65% ZSM-5 molecular sieve + 35% alumina binder) is used. Under the conditions of a reaction temperature of 530°C and a pressure of 1.2 MPa, the following products are generated in the light hydrocarbon production unit: 42% light hydrocarbons, 3% dry gas, and the remainder is water.

[0082] Subsequently, the carbon-containing compounds generated in the light hydrocarbon production unit are subjected to an adsorption dehydration unit; the dry gas removal unit removes water and dry gas in turn, and the products enter the aromatics production unit. The aromatics production unit adopts a fixed bed reactor and a commercial aromatization catalyst (from Example 1 of CN201510141378). By controlling the external heat, the reaction conditions of the aromatics production unit are controlled at: the average temperature in the reactor is 470°C and the pressure is 2.3MPa; then the product is separated by the quenching unit and the aromatics separation unit.

[0083] By adopting the above technical solution, the carbon-based yield of aromatics in the product reaches 70%, and the aromatics production unit does not require additional heat supply.

[0084] Example 2

[0085] The same as Example 1, except that the reaction conditions of the aromatic hydrocarbon production unit are adjusted. The coupled reactor of the present invention is used, methanol is used as a raw material, the raw material is introduced into the light hydrocarbon production unit, and a commercial MTP catalyst (65% ZSM-5 molecular sieve + 35% alumina binder) is used. Under the conditions of a reaction temperature of 530° C. and a pressure of 1.2 MPa, the light hydrocarbon production unit generates the following products: 42% light hydrocarbons, 3% dry gas, and the remainder is water.

[0086] Subsequently, the carbon-containing compounds generated in the light hydrocarbon production unit are subjected to an adsorption dehydration unit; after the water and dry gas are removed in the dry gas removal unit in turn, the products enter the aromatics production unit. The aromatics production unit adopts a fixed bed reactor and a commercial aromatization catalyst (from Example 1 of CN201510141378). By controlling the external heat, the reaction conditions of the aromatics production unit are controlled at: the average temperature in the reactor is 480°C and the pressure is 0.3MPa; then the products are separated by the quenching unit and the aromatics separation unit.

[0087] By adopting the above technical solution, the carbon-based yield of aromatics in the product reaches 66%, and the aromatics production unit does not require additional heat supply.

[0088] Example 3

[0089] The same as Example 1, except that the reaction conditions of the light hydrocarbon production unit are adjusted. The coupled reactor of the present invention is used, methanol is used as a raw material, the raw material is introduced into the light hydrocarbon production unit, and a commercial MTP catalyst (65% ZSM-5 molecular sieve + 35% alumina binder) is used. Under the conditions of a reaction temperature of 510° C. and a pressure of 0.2 MPa, the light hydrocarbon production unit generates the following products: 40% light hydrocarbons, 5% dry gas, and the remainder is water.

[0090] Subsequently, the carbon-containing compounds generated in the light hydrocarbon production unit are subjected to an adsorption dehydration unit; the dry gas removal unit removes water and dry gas in turn, and the products enter the aromatics production unit. The aromatics production unit adopts a fixed bed reactor and a commercial aromatization catalyst (from Example 1 of CN201510141378). By controlling the external heat, the reaction conditions of the aromatics production unit are controlled to: the average temperature in the reactor can reach 470°C and the pressure is 2.3MPa; then the product is separated by the quenching unit and the aromatics separation unit.

[0091] By adopting the above technical solution, the carbon-based yield of aromatics in the product reaches 62%, and the aromatics production unit does not require additional heat supply.

[0092] Example 4

[0093] The difference is the same as in Example 1, the product of the light hydrocarbon production unit directly enters the aromatic hydrocarbon production unit without passing through the adsorption unit and the dry gas removal unit. The coupling reactor of the present invention is used, methanol is used as a raw material, the raw material is introduced into the light hydrocarbon production unit, and a commercial MTP catalyst (65% ZSM-5 molecular sieve + 35% alumina binder) is used. Under the conditions of a reaction temperature of 530°C and a pressure of 1.2MPa, the light hydrocarbon production unit generates the following products: 42% light hydrocarbons, 3% dry gas, and the rest is water.

[0094] Subsequently, all the products of the light hydrocarbon production unit enter the aromatics production unit. The aromatics production unit adopts a fixed bed reactor and a commercial aromatization catalyst (from Example 1 of CN201510141378). By taking external heat, the reaction conditions of the aromatics production unit are controlled as follows: the average temperature in the reactor is maintained at 470°C and the pressure is 2.3 MPa; then the products are separated by the quenching unit and the aromatics separation unit.

[0095] By adopting the above technical solution, the carbon-based yield of aromatics in the product reaches 60%, and the aromatics production unit does not require additional heat supply.

[0096] Comparative Example 1

[0097] Two uncoupled independent light hydrocarbon production units and aromatic hydrocarbon production units are used, methanol is used as raw material, and the raw material is introduced into the light hydrocarbon production unit. Using a commercial MTP catalyst (65% ZSM-5 molecular sieve + 35% alumina binder), under the conditions of reaction temperature of 530°C and pressure of 1.2MPa, the following products are generated in the light hydrocarbon production unit: 42% light hydrocarbons, 1% hydrogen, and the rest is water.

[0098] Subsequently, the carbon-containing compounds generated in the light hydrocarbon production unit are removed in the adsorption dehydration unit; the dry gas removal unit removes water and dry gas in turn, and the products enter the aromatics production unit. The aromatics production unit adopts a fixed bed reactor and a commercial aromatization catalyst (from Example 1 of CN201510141378).

[0099] Among them, the excess heat of the light hydrocarbon production unit is brought in by the raw materials of the aromatic hydrocarbon production unit through heat exchange. The reaction conditions are: the average temperature in the reactor is only 370°C and the pressure is 0.3MPa.

[0100] By adopting the above technical solution, under the condition that no additional heat is supplied to the aromatics production unit, the carbon-based yield of aromatics in the product is only 49%.

[0101] 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. A system for producing aromatics, characterized in that: The system includes: coupled reactor; and an adsorption dehydration unit (②) and a dry gas removal unit (③) disposed between the light hydrocarbon production unit (①) and the aromatic hydrocarbon production unit (④) connecting pipelines of the coupled reactor; A quenching unit (⑤) and an aromatics separation unit (⑥) connected in series with the product outlet of the aromatics production unit; The coupled reactor comprises a light hydrocarbon production unit and an aromatic hydrocarbon production unit which are coaxially distributed in partitions, a heat-conducting interlayer is arranged between the light hydrocarbon production unit and the aromatic hydrocarbon production unit, and the light hydrocarbon production unit and the aromatic hydrocarbon production unit can be connected to realize material flow; the light hydrocarbon production unit is loaded with a light hydrocarbon production catalyst and is located outside the aromatic hydrocarbon production unit, and the aromatic hydrocarbon production unit is loaded with an aromatic hydrocarbon production catalyst.

2. The system according to claim 1, wherein: The feed inlet of the light hydrocarbon production unit and the feed inlet of the aromatic hydrocarbon production unit are arranged so that the axial flow direction of the feed of the aromatic hydrocarbon production unit is opposite to the axial flow direction of the feed of the light hydrocarbon production unit; and / or The product outlet of the light hydrocarbon production unit is connected to the raw material inlet of the aromatic hydrocarbon production unit through a pipeline.

3. The system according to claim 1 or 2, wherein: The raw material inlet of the light hydrocarbon production unit is at one end of the outer wall, and the product outlet is at the other end of the outer wall. Preferably, the raw material inlet and the product outlet are centrally symmetrically distributed; and / or The raw material inlet of the aromatics production unit is one axial end of the unit, and the product outlet is the other axial end. Preferably, the raw material inlet and the product outlet are centrally symmetrically distributed.

4. The system according to any one of claims 1 to 3, wherein: The adsorption dehydration unit (②) comprises a top inlet and a bottom outlet; and / or The dry gas removal unit (③) has a bottom inlet and a top outlet; and / or The quenching unit (⑤) has a bottom inlet and a top outlet; and / or The aromatic separation unit (⑥) comprises a top non-aromatic hydrocarbon stream outlet and a bottom aromatic hydrocarbon stream outlet.

5. The system according to any one of claims 1 to 4, wherein: The inlet end of the aromatics production unit is equipped with a flow distribution plate; and / or The heat-conducting medium of the heat-conducting interlayer is heat-conducting oil and / or heat-conducting molten salt.

6. A method for producing aromatic hydrocarbons, characterized in that The method is carried out in a system as described in any one of claims 1 to 5, and the method comprises: (1) passing the raw material into a light hydrocarbon production unit to obtain a product mainly containing carbon-containing compounds, dry gas and water; (2) The carbon-containing compounds are sent to an aromatics production unit through a pipeline to obtain a product mainly containing aromatics and non-aromatics.

7. The method according to claim 6, wherein: The operating conditions of the light hydrocarbon production unit include: The reaction temperature is 320-630°C, preferably 370-550°C; and / or the pressure is 0.05-3.2MPa; and / or The catalyst contains 50-90 wt% of molecular sieve and 10-50 wt% of alumina; and / or The operating conditions of the aromatics production unit include: a reaction temperature of 430-580°C, preferably 450-530°C; and / or a pressure of 0.1-2.8 MPa.

8. The method according to claim 6 or 7, wherein: The products containing carbon compounds, dry gas and water are successively sent to the aromatics production unit through a pipeline after the water and dry gas are removed by an adsorption dehydration unit and a dry gas removal unit to obtain products mainly containing aromatics and non-aromatics.

9. The method according to any one of claims 6 to 8, wherein: The product of the aromatics production unit is successively passed through a quenching unit and an aromatics separation unit to separate two streams of materials, one of which is a non-aromatics stream and the other is an aromatics stream, wherein the aromatics stream is the final product.

10. The method according to any one of claims 6 to 9, wherein: The operating conditions of the adsorption dehydration unit include: adsorption temperature of 10-150°C, preferably 20-125°C; adsorption pressure of 0.1-2.8MPa, preferably 0.15-2.5Mpa; adsorbent selected from one or more of molecular sieve, alumina, calcium chloride, silica gel; and / or The operating conditions of the dry gas removal unit include: an operating temperature of 5-180°C, preferably 10-160°C; an operating pressure of 0.1-2.5MPa, preferably 0.15-2.2Mpa; and / or The operating conditions of the quench unit include: outlet temperature of 5-80°C, preferably 10-65°C; operating pressure of 0.1-2.2MPa, preferably 0.15-2.0MPa; and / or The operating conditions of the aromatic separation unit include: outlet temperature of 0-70°C, preferably 5-65°C; operating pressure of 0.1-2.0 MPa, preferably 0.15-2.0 MPa.

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