System and method for simultaneously preparing aromatic hydrocarbon and olefin from synthesis gas

Abstract

The invention provides a system and a method for simultaneously preparing aromatic hydrocarbon and olefin from synthesis gas. The system comprises an aromatic hydrocarbon synthesis device, a first separation device, an olefin synthesis device, a second separation device and a third separation device which are sequentially communicated in series, and a light olefin conversion device communicated with the second separation device, by integrating two preparation routes for preparing aromatic hydrocarbon and olefin from synthesis gas, compared with a single system for preparing aromatic hydrocarbon from synthesis gas and a single system for preparing olefin from synthesis gas, the construction investment of the integrated system is effectively reduced; moreover, the preparation of aromatic hydrocarbon from the synthesis gas needs to be completed under high pressure, and the pressure is continuously utilized by the subsequent separation and the process of preparing olefin from the synthesis gas, so that the synthesis energy consumption is greatly reduced; besides, C5-C10 hydrocarbon in the olefin product is separated and converted into C2-C4 olefin and a small amount of aromatic hydrocarbon, so that the yield of olefin and aromatic hydrocarbon is effectively improved, and the proportion of light olefin and aromatic hydrocarbon in the product gas is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing aromatics and olefins from synthesis gas, and in particular to a system and method for preparing aromatics and olefins from synthesis gas. Background Art

[0002] The one-step synthesis gas process for the preparation of aromatics or olefins (synthesis gas → aromatics / olefins) is a rapidly developing technology in recent years. Its main advantages are short process, low investment and low carbon emissions. Compared with the original multi-step synthesis route, that is, synthesis gas is first used to prepare methanol, and methanol is then used to prepare aromatics or olefins (synthesis gas → methanol → aromatics / olefins), this technology is a one-step process for the preparation of aromatics or olefins by coupling the original high-pressure, low-temperature reaction environment (used for methanol synthesis, generally 4-8MPa, 180-270℃) with a low-pressure, high-temperature reaction environment (methanol to olefins or aromatics, generally 0.2-0.5MPa, 350-500℃). At present, the CO conversion rate of the one-step synthesis gas process for the preparation of aromatics or olefins can reach 20%~50%, and the aromatics or olefins selectivity can reach 50%~80%. However, there are still problems such as difficult matching of reaction areas, difficult catalyst design, difficult process continuity, and the need to continuously improve product selectivity. Moreover, when the CO conversion rate increases, the CO2 selectivity is difficult to control, and when the total yield of aromatics or olefins increases, the selectivity of light olefins and light aromatics decreases; these problems have not been well solved in the past decade. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention provides a system and method for preparing aromatics and olefins from synthesis gas, so as to achieve the purpose of simultaneously producing aromatics and light olefins.

[0004] The specific content of the invention is as follows: In a first aspect, the present invention provides a system for preparing aromatics and olefins from synthesis gas, comprising: an aromatics synthesis unit, an olefin synthesis unit, a light olefin conversion unit and a plurality of separation units; wherein: The aromatics synthesis unit, the first separation unit, the olefin synthesis unit, the second separation unit and the third separation unit are connected in series in sequence, and the second separation unit is connected to the light olefin conversion unit; The aromatics synthesis device is used to catalytically convert synthesis gas into aromatics to obtain a first mixed gas containing aromatics; The first separation device is used to receive and cool the first mixed gas to liquefy the aromatic hydrocarbons and water vapor therein, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; The olefin synthesis device is used to receive the second mixed gas and the fresh synthesis gas, and perform olefin conversion reaction to obtain C1-C 10 a third mixed gas of hydrocarbons; The second separation device is used to receive and cool the third mixed gas, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; The third separation device is used to receive the fourth mixed gas and perform pressure swing adsorption to separate C2-C4 hydrocarbons from small molecule gases H2, CO, CO2 and CH4; The light olefin conversion unit is used to receive the liquefied C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics.

[0005] Optionally, the aromatics synthesis device is filled with a metal oxide-molecular sieve catalyst; wherein, The metal oxide includes: one or more of zinc oxide, gallium oxide and germanium oxide; The molecular sieve includes one or more of ZSM-5, ZSM-11, and ZSM-22; The operating temperature of the aromatics synthesis unit is 250-380°C, and the operating pressure is 2.1-6.1MPa.

[0006] Optionally, the first separation device cools the first mixed gas to liquefy the aromatic hydrocarbons and water vapor therein by setting a first temperature control device; wherein, The temperature control range of the first temperature control device includes -20~0 ℃.

[0007] Optionally, the olefin synthesis device is filled with a catalyst whose active component is a metal carbide; wherein the metal carbide includes: one or more of iron carbide, cobalt carbide and nickel carbide; The operating temperature of the olefin synthesis unit is 250-380°C.

[0008] Optionally, the second separation device cools the third mixed gas by setting a second temperature control device so that the H2O, C5-C 10 The purpose of hydrocarbon liquefaction; wherein, The temperature control range of the second temperature control device includes -60~-35°C.

[0009] Optionally, the third separation device comprises a pressure sub-control device and a plurality of third separation sub-devices arranged in parallel, and the plurality of third separation sub-devices are all filled with adsorbent; wherein, The adsorbent is an inorganic oxide, a molecular sieve or carbon, and the pore size of the adsorbent meets the requirement that more than 85% of the pore size is 0.4-0.5 nm.

[0010] Optionally, the light olefin conversion unit is filled with a molecular sieve or a metal-molecular sieve-based catalyst; wherein the metal is one or more of gallium, zinc, copper and manganese, and the molecular sieve is ZSM-5, ZSM-22 or ZSM-11; The acid amount of the molecular sieve and the metal-molecular sieve-based catalyst is 10 -5 -10 -3 mmol / g; The light olefin conversion unit is provided with a third temperature control device, and the temperature control range of the third temperature control device includes 450-600°C.

[0011] In a second aspect, the present invention provides a method for jointly preparing aromatics and olefins from synthesis gas, the method being applicable to the system for jointly preparing aromatics and olefins from synthesis gas as described in the first aspect, the method comprising: The reaction zone of the aromatics synthesis unit is filled with a metal oxide-molecular sieve catalyst, the reaction zone of the olefin synthesis unit is filled with a catalyst whose active component is a metal carbide, and the reaction zone of the light olefin conversion unit is filled with a molecular sieve or a metal-molecular sieve-based catalyst; the third separation unit is filled with an adsorbent Controlling the working pressure of the aromatics synthesis unit to 2.1-6.1 MPa and the working temperature to 250-380°C, controlling the working temperature of the first separation unit to -20~0°C, controlling the working temperature of the olefin synthesis unit to 250-380°C, controlling the working temperature of the second separation unit to -60~-35°C, and controlling the working temperature of the light olefin conversion unit to 450-600°C; Passing synthesis gas with a H2 / CO ratio of 1.5:1 to 2.2:1 into the aromatics synthesis device to convert aromatics to obtain a first mixed gas containing aromatics; Passing the first mixed gas into the first separation device to liquefy the aromatic hydrocarbons and water vapor in the first mixed gas, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; The second mixed gas is introduced into an olefin synthesis unit as a reaction gas, and fresh synthesis gas is further added to carry out olefin conversion reaction to obtain a C1-C 10 a third mixed gas of hydrocarbons; The third mixed gas is introduced into the second separation device, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; Passing the fourth mixed gas into a third separation device, so that the adsorbent in the third separation device adsorbs C2-C4 hydrocarbons in the fourth mixed gas, and the remaining small molecule gas containing H2, CO, CO2 and CH4; The liquefied C5-C 10 The hydrocarbons are introduced into the light olefin conversion unit to undergo a light olefin conversion reaction to obtain C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics; The C2-C4 olefins generated in the light olefin conversion unit and the C2-C4 hydrocarbons obtained by adsorption in the third separation unit are combined and collected, and the aromatics generated in the light olefin conversion unit and the aromatics obtained by liquefaction in the first separation unit are combined and collected.

[0012] Optionally, in the olefin synthesis unit, the volume flow rate of the fresh synthesis gas introduced is 3-10 times that of the second mixed gas introduced.

[0013] Optionally, in the aromatics synthesis unit, the CO single-pass conversion rate is 40-60%, and the aromatics selectivity is 75%-90% based on the hydrocarbon base; In the olefin synthesis device, the CO single-pass conversion rate is 90-98%; based on the hydrocarbon base, the olefin selectivity is 65%-80%, wherein based on the olefin base, the C2-C4 olefin is 65-85%.

[0014] Compared with the prior art, the present invention has the following advantages: The present invention provides a system for preparing aromatics and olefins by synthesizing gas, comprising: an aromatics synthesis device, an olefin synthesis device, a light olefin conversion device and a plurality of separation devices; wherein the aromatics synthesis device, the first separation device, the olefin synthesis device, the second separation device and the third separation device are sequentially connected in series, and the second separation device is connected to the light olefin conversion device; the aromatics synthesis device is used for catalytically converting the synthesis gas into aromatics to obtain a first mixed gas containing aromatics; the first separation device is used for receiving and cooling the first mixed gas to liquefy the aromatics and water vapor therein, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; the olefin synthesis device is used for receiving the second mixed gas and fresh synthesis gas, and performing olefin conversion reaction to obtain a C1-C 10 The second separation device is used to receive and cool the third mixed gas, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; the third separation device is used to receive the fourth mixed gas and perform adsorption treatment to separate C2-C4 hydrocarbons from small molecule gases H2, CO, CO2 and CH4; the light olefin conversion device is used to receive the liquefied C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics.

[0015] The present invention integrates two preparation routes of preparing aromatics from syngas and preparing olefins from syngas. Compared with building a single system of preparing aromatics from syngas and a single system of preparing olefins from syngas, the construction investment of the integrated system is effectively reduced. In addition, the present invention first prepares aromatics from syngas in an aromatics synthesis unit. Since the preparation of aromatics from syngas needs to be completed under high pressure, this pressure is continuously utilized by the subsequent separation and preparation of olefins from syngas, so that the synthesis energy consumption is greatly reduced. In addition, the present invention separates C5-C 10 It can convert hydrocarbons into C2-C4 olefins and a small amount of aromatics, effectively improving the olefin yield (yield increased by 5-20%) and increasing the proportion of light olefins in the product gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the system structure for preparing aromatics and olefins from synthesis gas provided by an embodiment of the present invention is shown; Figure 2 The flowchart of the method for jointly preparing aromatics and olefins from synthesis gas provided by an embodiment of the present invention is shown.

[0018] Description of reference numerals: 1. Aromatics synthesis unit; 2. First separation unit; 3. Olefin synthesis unit; 4. Second separation unit; 5. Third separation unit; 6. Light olefin conversion unit; 7. First transmission pipeline; 8. Second transmission pipeline; 9. Fourth transmission pipeline; 10. Sixth transmission pipeline; 11. Eighth transmission pipeline; 12. Ninth transmission pipeline; 13. Tenth transmission pipeline 13; 14. Seventh transmission pipeline; 15. Second outlet; 16. Eleventh transmission pipeline; 17. Third transmission pipeline; 18. First outlet; 19. Fifth transmission pipeline 19; 20. Third outlet. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. In addition, all other embodiments obtained by ordinary technicians in this field without carrying out creative work belong to the scope of protection of the present invention.

[0020] In the embodiment, no specific experimental steps or conditions are indicated, and the operation or conditions of the conventional experimental steps described in the prior art in this field can be carried out. The reagents used and other instruments that do not indicate the manufacturer are conventional reagent products that can be obtained commercially. In addition, the accompanying drawings are only schematic diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0021] Technologies, methods, and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the description of the present invention.

[0022] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] In a first aspect, the present invention provides a system for preparing aromatics and olefins from synthesis gas. Figure 1 The schematic diagram of the system structure for preparing aromatics and olefins from synthesis gas provided by an embodiment of the present invention is shown as follows: Figure 1As shown, the system for jointly preparing aromatics and olefins from synthesis gas includes: an aromatics synthesis unit 1, an olefins synthesis unit 3, a light olefins conversion unit 6 and a plurality of separation units; the plurality of separation units include a first separation unit 2, a second separation unit 4, and a third separation unit 5; wherein the aromatics synthesis unit 1, the first separation unit 2, the olefins synthesis unit 3, the second separation unit 4 and the third separation unit 5 are sequentially connected in series, and the second separation unit 4 is connected to the light olefins conversion unit 6.

[0025] See also Figure 1 The aromatics synthesis device 1 is provided with a first transmission pipeline 7 for inputting synthesis gas into the aromatics synthesis device 1 to carry out a catalytic conversion reaction of aromatics. The reaction zone of the aromatics synthesis device 1 is filled with a metal oxide-molecular sieve catalyst ( Figure 1 ); the synthesis gas entering the aromatic synthesis device 1 is catalytically converted into aromatics under the catalytic action of the metal oxide-molecular sieve catalyst to obtain a first mixed gas containing aromatics; since the catalytic conversion of the synthesis gas into aromatics needs to be carried out under high temperature and high pressure conditions (temperature of 250-380°C, pressure of 2.1-6.1MPa), the reaction pressure is slightly higher than the pressure conditions required for the catalytic conversion of the synthesis gas into olefins. Therefore, the present invention takes the catalytic conversion of the synthesis gas into aromatics as the starting point of the reaction to design the connection relationship between the various devices in the separation and reaction processes in the system, so that this pressure is continuously utilized by the subsequent separation and reaction processes, and the synthesis energy consumption is greatly reduced.

[0026] In some embodiments, the metal oxide in the metal oxide-molecular sieve catalyst can be selected from one or more of zinc oxide, gallium oxide and germanium oxide; the molecular sieve can be selected from one or more of ZSM-5, ZSM-11 and ZSM-22.

[0027] See also Figure 1 The first separation device 2 is connected in series with the aromatic synthesis device 1 through the second transmission pipeline 8 to receive the first mixed gas formed by the reaction in the aromatic synthesis device 1, and cool the first mixed gas to liquefy the aromatics and water vapor therein, thereby separating from other gases, and the generated water is discharged from the first separation device 2 through the first outlet 18, and the liquefied aromatics are discharged from the first separation device 2 as a product through the third transmission pipeline 17. The remaining gas in the first separation device 2 is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes.

[0028] In some embodiments, the first separation device 2 is provided with a first temperature control device having a temperature control range of -20 to 0° C. to achieve liquefaction of aromatic hydrocarbons and water vapor and separation from other gases.

[0029] In a specific implementation, the reaction zone of the olefin synthesis device 3 is filled with a catalyst whose active component is a metal carbide. The olefin synthesis device 3 is connected in series with the first separation device 2 through a fourth transmission pipeline 9 to receive the remaining second mixed gas in the first separation device 2. At the same time, a certain amount of fresh synthesis gas is added to the olefin synthesis device 3 through a fifth transmission pipeline 19 provided in the olefin synthesis device 3. The olefin synthesis device 3 uses the fresh synthesis gas and the unreacted synthesis gas in the second mixed gas as reaction raw materials, and performs olefin conversion reaction under the action of the catalyst, thereby obtaining C1-C 10 a third mixed gas of hydrocarbons; since the pressure required for the olefin conversion process is slightly lower than that for the aromatic conversion process, the olefin synthesis unit 3 only needs to adjust the operating temperature to 250-380°C, without the need to set up an additional pressure control device, and the pressure of the aromatic conversion process can be effectively utilized to complete the conversion.

[0030] In some embodiments, the metal carbide catalyst may be selected from one or more of iron carbide, cobalt carbide, and nickel carbide.

[0031] In specific implementation, the second separation device 4 is connected in series with the olefin synthesis device 3 through the sixth transmission pipeline 10 to receive the third mixed gas formed by the reaction in the olefin synthesis device 3, and cool the third mixed gas to reduce the temperature of the water vapor and C5-C 10 The hydrocarbons are liquefied and separated, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; in some embodiments, the second separation device 4 cools the third mixed gas by setting a second temperature control device with a temperature control range of -60 to -35 ° C, so that the water vapor and C5-C 10 Hydrocarbon liquefaction purpose.

[0032] See also Figure 1 The second separation device 4 is also provided with a seventh transmission pipeline 14 and a second outlet 15. The seventh transmission pipeline 14 is used to transfer the liquefied C5-C 10 The hydrocarbons are transferred to the light olefin conversion device 6 , and the second outlet 15 is used to discharge the liquefied water vapor out of the second separation device 4 .

[0033] In specific implementation, the third separation device 5 is filled with an adsorbent, and the third separation device 5 is connected in series with the second separation device 4 through the eighth transmission pipeline 11 to receive the remaining fourth mixed gas in the second separation device 4 and adsorb and absorb the C2-C4 hydrocarbons therein, and the remaining small molecule gases containing H2, CO, CO2 and CH4. Figure 1 The third separation device 5 removes the remaining small molecule gas containing H2, CO, CO2 and CH4 out of the third separation device 5 through the third outlet 20. The adsorbent adsorbed with C2-C4 hydrocarbons is decomposed and released after decompression, and is removed from the third separation device 5 through the ninth transmission pipeline 12 for collection.

[0034] It should be noted that the adsorption process carried out in the third separation device 5 is a technology for achieving target gas separation based on the adsorption characteristics of the adsorption object and the spatial confinement effect of the adsorbent. In the embodiment of the present invention, the third separation device 5 includes a pressure control device and a plurality of third separation sub-devices arranged in parallel. When the adsorbent in one of the third separation sub-devices is saturated with adsorption, it is immediately switched to another third separation sub-device to continue adsorption, and then the saturated third separation sub-device is subjected to pressure swing desorption treatment. Specifically, the pressure of the third separation sub-device is controlled by the pressure control device to make the pressure of the third separation sub-device 0.06-1MPa, and the C2-C4 hydrocarbon gas adsorbed by the adsorbent is desorbed and released under a lower pressure environment. After the pressure swing desorption is completed, the third separation sub-device can participate in the adsorption of C2-C4 hydrocarbon gas again after the pressure control device performs pressure regulation (pressurization treatment is performed as needed to make the pressure in the third separation sub-device after desorption treatment adapt to the pressure in the eighth transmission pipeline 11).

[0035] In some embodiments, the adsorbent filled in the third separation device 5 is selected from inorganic oxides, molecular sieves or carbon, and the pore size of the adsorbent meets the requirement that more than 85% of the pore size is 0.4-0.5 nm.

[0036] In specific implementation, the light olefin conversion unit 6 is filled with pure molecular sieves or metal-molecular sieve catalysts. It should be noted that the metal-molecular sieve catalysts filled are all low-acid catalysts, and the acid content on the catalyst surface is 0.01%-0.1% of the acid content (0.1-1 mmol / g) of hydrogen-type ZSM-5 (silicon-aluminum ratio 120); that is, the acid content of the pure molecular sieve or metal-molecular sieve catalyst is 10 -5 -10 -3 mmol / g; specifically, the metal component in the metal-molecular sieve catalyst can be selected from one or more of gallium, zinc, copper and manganese, and the pure molecular sieve or the molecular sieve in the catalyst can be selected from ZSM-5, ZSM-22 or ZSM-11.

[0037] In a specific implementation, the liquefied C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics under the action of a low-acid catalyst. This conversion needs to be carried out at 450-600°C. In some embodiments, the light olefin conversion unit is provided with a third temperature control device with a temperature control range of 450-600°C to meet the temperature requirements of the light olefin conversion process.

[0038] Continue to see Figure 1The light olefin conversion unit 6 is provided with a tenth transmission pipeline 13, which can be partially merged with the ninth transmission pipeline 12 to realize the combined collection of C2-C4 hydrocarbons obtained after analysis by the third separation unit and C2-C4 olefins generated in the light olefin conversion unit 6; in addition, the light olefin conversion unit 6 is also provided with an eleventh transmission pipeline 16, which can be partially merged with the third transmission pipeline 17 to realize the combined collection of aromatics generated in the light olefin conversion unit 6 and aromatics obtained by liquefaction in the first separation unit 2.

[0039] The present invention integrates two preparation routes of preparing aromatics from syngas and preparing olefins from syngas. Compared with building a single system of preparing aromatics from syngas and a single system of preparing olefins from syngas, the construction investment of the integrated system is effectively reduced. In addition, the present invention firstly prepares aromatics from syngas in an aromatics synthesis device. Since the preparation of aromatics from syngas needs to be completed under high pressure, this pressure is continuously utilized by the subsequent separation and preparation of olefins from syngas, so that the synthesis energy consumption is greatly reduced. In addition, the present invention further separates C5-C 10 It can convert hydrocarbons into C2-C4 olefins and a small amount of aromatics, effectively improving the olefin yield (yield increased by 5-20%) and increasing the proportion of light olefins in the product gas.

[0040] In a second aspect, the present invention provides a method for the joint preparation of aromatics and olefins from synthesis gas, and the method is applicable to the system for the joint preparation of aromatics and olefins from synthesis gas described in the first aspect. First, a metal oxide-molecular sieve catalyst is filled into the reaction zone of an aromatics synthesis unit, a catalyst whose active component is a metal carbide is filled into the reaction zone of an olefin synthesis unit, and a molecular sieve or a low-acid metal-molecular sieve-based catalyst is filled into the reaction zone of a light olefin conversion unit; an adsorbent is filled into a third separation unit; the working pressure of the aromatics synthesis unit is controlled to be 2.1-6.1MPa, and the working temperature is controlled to be 250-380°C, the working temperature of the first separation unit is controlled to be -20~0°C, the working temperature of the olefin synthesis unit is controlled to be 250-380°C, the working temperature of the second separation unit is controlled to be -60~-35°C, and the working temperature of the light olefin conversion unit is controlled to be 450-600°C, and then the joint preparation of aromatics and olefins is started. Figure 2 The flow chart of the method for preparing aromatics and olefins from synthesis gas provided by an embodiment of the present invention is shown as follows: Figure 2 As shown, the method includes: S1, introducing a synthesis gas with a H2 / CO ratio of 1.5:1 to 2.2:1 into an aromatics synthesis unit to convert aromatics to obtain a first mixed gas containing aromatics; S2, passing the first mixed gas into a first separation device to liquefy the aromatic hydrocarbons and water vapor in the first mixed gas, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; S3, passing the second mixed gas as a reaction gas into an olefin synthesis device, and further supplementing with fresh synthesis gas to carry out olefin conversion reaction to obtain a C1-C 10 a third mixed gas of hydrocarbons; S4, the third mixed gas is passed into the second separation device, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; S5, passing the fourth mixed gas into the third separation device, so that the adsorbent in the third separation device adsorbs C2-C4 hydrocarbons in the fourth mixed gas, and the remaining small molecule gas containing H2, CO, CO2 and CH4; S6, the liquefied C5-C 10 The hydrocarbons are introduced into the light olefin conversion unit for light olefin conversion reaction to obtain C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics; S7. Combine and collect the C2-C4 olefins generated in the light olefin conversion unit and the C2-C4 hydrocarbons obtained by adsorption in the third separation unit, and combine and collect the aromatics generated in the light olefin conversion unit and the aromatics obtained by liquefaction in the first separation unit.

[0041] In some embodiments, the third separation device may be provided with multiple third separation sub-devices and pressure control sub-devices in parallel, such as 2-6. When the adsorbent in one of the third separation sub-devices is saturated with adsorption, it is immediately switched to another third separation sub-device to continue adsorption, and then the saturated adsorbent is subjected to pressure swing desorption. Specifically, the pressure of the third separation sub-device is maintained at 0.06-1 MPa by manipulating the pressure control sub-device, and hydrocarbons (C2-C4 hydrocarbons) with a diameter greater than 0.4 nm adsorbed by the adsorbent are desorbed and released under a lower pressure environment. After the third separation sub-device has completed the pressure swing desorption, it can participate in the adsorption of C2-C4 hydrocarbon gas again after the pressure control device performs pressure regulation (performs a pressure boosting process as needed to make the pressure in the third separation sub-device after the desorption process compatible with the pressure in the eighth transmission pipeline 11).

[0042] It should be noted that in the aromatics synthesis unit, the CO single-pass conversion rate is 40-60%, and the aromatics selectivity is 75%-90% based on the hydrocarbon base; It should also be noted that the volume flow rate of the fresh synthesis gas introduced into the olefin synthesis unit is 3-10 times that of the second mixed gas introduced, so as to control the CO single-pass conversion rate in the olefin synthesis unit to be 90-98%; based on the hydrocarbon base, the olefin selectivity is 65%-80%, among which the C2-C4 olefins based on the olefin base are 65-85%.

[0043] In order to enable those skilled in the art to more clearly understand the present invention, a system and method for preparing aromatics and olefins from synthesis gas provided by the present invention are now described in detail through the following examples.

[0044] according to Figure 1 The schematic diagram of the system structure of the synthesis gas for preparing aromatics and olefins is shown, wherein the aromatics synthesis unit 1, the first separation unit 2, the olefin synthesis unit 3, the second separation unit 4 and the third separation unit 5 are connected in series in sequence, and the second separation unit 4 is connected to the light olefin conversion unit 6, so as to form a complete system. Figure 1 The system for jointly preparing aromatics and olefins from synthesis gas is shown.

[0045] Example 1 The synthesis gas (H2:CO ratio of 1.8:1) is introduced into the aromatics synthesis unit 1 through the first transmission pipeline 7, and a catalyst with an active site of metal oxide-molecular sieve (the oxide is germanium oxide, iron oxide, and the molecular sieve is ZSM-5) is used; the temperature of the aromatics synthesis unit 1 is controlled to be 250-270°C and the pressure is 3.1 MPa. The synthesis gas is catalytically converted into aromatics, wherein the CO single-pass conversion rate is 55% and the aromatics selectivity (hydrocarbon base) is 83%.

[0046] After the reaction, the first mixed gas containing aromatics (synthesis gas, CO2, water, aromatics, and a small amount of alkanes) obtained by the aromatics synthesis unit 1 enters the first separation unit 2 through the second transmission pipeline 8. At -10°C and 3.05MPa, the aromatics and water vapor are liquefied and separated from other gases, wherein the generated water is discharged through the first outlet 18; the liquefied aromatics are discharged as products through the third transmission pipeline 17; the remaining gas is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes, which enters the olefin synthesis unit 3 through the fourth transmission pipeline 9.

[0047] Another stream of fresh synthesis gas (H2:CO ratio of 1.7:1, its flow rate is 5 times the volume flow rate of the second mixed gas) is passed from the fifth transmission pipeline 19 to the olefin synthesis unit 3, and the temperature is controlled to be 300-320°C and the pressure is 3 MPa. A catalyst with metal carbide as the active site (metal carbide is 99% iron carbide and 1% nickel carbide) is used to carry out olefin conversion reaction to obtain a third mixed gas containing C1-C9 hydrocarbons, wherein the CO single-pass conversion rate is 94%, the hydrocarbon product is C1-C9, and the olefin selectivity (hydrocarbon base) is 78%. C2-C4 olefins (olefin base) are 78%. The third mixed gas enters the second separation device 4 through the sixth transmission pipeline 10.

[0048] The third mixed gas entering the second separation device 4 is separated into liquid form from water and C5-C9 alkanes / olefins at -50°C and 2.9 MPa, leaving a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons; the generated water is discharged through the second outlet 15; the liquefied C5-C9 alkanes / olefins are moved to the light olefin conversion device 6 through the seventh transmission pipeline 14.

[0049] The third separation device 5 is filled with an adsorbent (80% molecular sieve and 20% carbon; more than 85% of the pore size is 0.4-0.5 nm). After the fourth mixed gas enters the third separation device 5 through the eighth transmission pipeline 11, the C2-C4 olefins / alkanes therein are pressure-swing adsorbed and separated from other gases (H2, CO, CO2, CH4).

[0050] When the third separation device 5 includes a plurality of third separation sub-devices arranged in parallel, after one of the third separation sub-devices is saturated with adsorption, the third transmission pipeline 11 is controlled to pass into another first separation device to continue adsorption, and the saturated third separation sub-device is desorbed. Specifically, the pressure in the saturated third separation sub-device is regulated to 0.1MPa, and the C2 and above hydrocarbons desorbed by reduced pressure are discharged from the third separation device 5 through the ninth transmission pipeline 12 for collection, and other small molecule gases (H2, CO, CO2, CH4) are discharged from the third separation device 5 through the third outlet 20. After the desorption, the third separation sub-device can be pressure-regulated (pressurized as needed to make the pressure in the third separation sub-device after desorption compatible with the pressure in the eighth transmission pipeline 11), and participate in the adsorption link of C2-C4 hydrocarbon gas again.

[0051] The C5-C9 alkanes / olefins transferred to the light olefin conversion unit 6 are heated to 100 % on a metal-molecular sieve-based catalyst with a low acid content (the metal is 0.001% gallium, 0.002% zinc, 0.003% copper, and 0.004% manganese. The molecular sieve is ZSM-5; the acid content on the catalyst surface is 5*10 -4mmol / g (0.05% of the acid amount of hydrogen ZSM-5 (silicon-aluminum ratio 120, acid amount of 1 mmol / g)) and at 480-520°C, C5-C9 olefins / alkanes are converted into C2-C4 olefins and a small amount of aromatics. After the products are cooled, the olefin products are collected through the tenth transmission pipeline 13 and combined with the logistics of the ninth transmission pipeline 12; the aromatic products are collected through the eleventh transmission pipeline 16 and combined with the logistics of the third transmission pipeline 17.

[0052] Example 2 The synthesis gas (H2:CO ratio of 2:1) is introduced into the aromatics synthesis unit 1 through the first transmission pipeline 7, and a catalyst with an active site of metal oxide-molecular sieve is used (the oxide is zinc oxide and the molecular sieve is ZSM-5); the temperature of the aromatics synthesis unit 1 is controlled to be 300-330°C and the pressure is 4.1 MPa, so that the synthesis gas is catalytically converted into aromatics, wherein the CO single-pass conversion rate is 50% and the aromatics selectivity (hydrocarbon base) is 80%.

[0053] After the reaction, the first mixed gas containing aromatics (synthesis gas, CO2, water, aromatics, and a small amount of alkanes) obtained by the aromatics synthesis unit 1 enters the first separation unit 2 through the second transmission pipeline 8. At -10°C and 4.05MPa, the aromatics and water vapor are liquefied and separated from other gases, wherein the generated water is discharged through the first outlet 18; the liquefied aromatics are discharged as products through the third transmission pipeline 17; the remaining gas is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes, which enters the olefin synthesis unit 3 through the fourth transmission pipeline 9.

[0054] Another stream of fresh synthesis gas (H2:CO ratio of 1.8:1, its flow rate is 5 times the volume flow rate of the second mixed gas) is passed from the fifth transmission pipeline 19 to the olefin synthesis unit 3, and the temperature is controlled to be 350-360°C and the pressure is 4 MPa. A catalyst with a metal carbide as the active site (the metal carbide is iron carbide) is used to carry out olefin conversion reaction to obtain a third mixed gas containing C1-C8 hydrocarbons, wherein the CO single-pass conversion rate is 95%, the hydrocarbon product is C1-C8, and the olefin selectivity (hydrocarbon base) is 74%. C2-C4 olefins (olefin base) are 75%. The third mixed gas enters the second separation device 4 through the sixth transmission pipeline 10.

[0055] The third mixed gas entering the second separation device 4 is separated into liquid form from water and C5-C8 alkanes / olefins at -45°C and 3.9 MPa, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; the generated water is discharged through the second outlet 15; and the liquefied C5-C8 alkanes / olefins are moved to the light olefin conversion device 6 through the seventh transmission pipeline 14.

[0056] The third separation device 5 is filled with an adsorbent (90% inorganic oxide and 10% molecular sieve; more than 85% of the adsorbent has a pore size of 0.4-0.5 nm). After the fourth mixed gas enters the third separation device 5 through the eighth transmission pipeline 11, the C2-C4 olefins / alkanes therein are pressure-swing adsorbed and separated from other gases (H2, CO, CO2, CH4).

[0057] When the third separation device 5 includes a plurality of third separation sub-devices arranged in parallel, after one of the third separation sub-devices is saturated with adsorption, the third transmission pipeline 11 is controlled to pass into another first separation device to continue adsorption, and the saturated third separation sub-device is desorbed. Specifically, the pressure in the saturated third separation sub-device is regulated to 0.4MPa, and the C2 and above hydrocarbons desorbed by reduced pressure are discharged from the third separation device 5 through the ninth transmission pipeline 12 for collection, and other small molecule gases (H2, CO, CO2, CH4) are discharged from the third separation device 5 through the third outlet 20. After the desorption, the third separation sub-device can be pressure-regulated (pressurized as needed to make the pressure in the third separation sub-device after desorption compatible with the pressure in the eighth transmission pipeline 11), and participate in the adsorption link of C2-C4 hydrocarbon gas again.

[0058] The C5-C8 alkanes / olefins transferred to the light olefin conversion unit 6 are heated on a metal-molecular sieve-based catalyst with a low acid content (the metal is 0.05% gallium, 0.008% manganese. The molecular sieve is 90% ZSM-5, 10% ZSM-11; the acid content on the catalyst surface is 10 -3 mmol / g (0.1% of the acid amount of hydrogen ZSM-5 (silicon-aluminum ratio 120, acid amount 1 mmol / g)), and at 550-560°C, C5-C8 olefins / alkanes are converted into C2-C4 olefins and a small amount of aromatics. After the product is cooled, the obtained olefin product is collected through the tenth transmission pipeline 13 and combined with the logistics of the ninth transmission pipeline 12; the aromatic product is collected through the eleventh transmission pipeline 16 and combined with the logistics of the third transmission pipeline 17.

[0059] Example 3 The synthesis gas (H2:CO ratio of 1.5:1) is introduced into the aromatics synthesis unit 1 through the first transmission pipeline 7, and a catalyst with an active site of metal oxide-molecular sieve (the oxide is germanium oxide and the molecular sieve is ZSM-5) is used; the temperature of the aromatics synthesis unit 1 is controlled to be 250-280°C and the pressure is 2.1 MPa. The synthesis gas is catalytically converted into aromatics, wherein the CO single-pass conversion rate is 40% and the aromatics selectivity (hydrocarbon base) is 75%.

[0060] After the reaction, the first mixed gas containing aromatics (synthesis gas, CO2, water, aromatics, and a small amount of alkanes) obtained by the aromatics synthesis unit 1 enters the first separation unit 2 through the second transmission pipeline 8. At -20°C and 2.05MPa, the aromatics and water vapor are liquefied and separated from other gases, wherein the generated water is discharged through the first outlet 18; the liquefied aromatics are discharged as products through the third transmission pipeline 17; the remaining gas is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes, which enters the olefin synthesis unit 3 through the fourth transmission pipeline 9.

[0061] Another stream of fresh synthesis gas (H2:CO ratio is 2.2:1, and its flow rate is 3 times the volume flow rate of the second mixed gas) is passed from the fifth transmission pipeline 19 to the olefin synthesis unit 3, and the temperature is controlled to be 320-350°C and the pressure is 2 MPa; a catalyst with metal carbide as the active site (metal carbide is 20% cobalt carbide and 80% iron carbide) is used to carry out olefin conversion reaction to obtain a third mixed gas containing C1-C7 hydrocarbons. Among them, the CO single-pass conversion rate is 90%, and the hydrocarbon products are C1-C7. The olefin selectivity (hydrocarbon base) is 65%. C2-C4 olefins (olefin base) are 85%. The third mixed gas enters the second separation device 4 through the sixth transmission pipeline 10.

[0062] In the third mixed gas entering the second separation device 4, water and C5-C7 alkanes / olefins are separated as liquid at -60°C and 2 MPa, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; wherein the generated water is discharged through the second outlet 15; and the liquefied C5-C7 alkanes / olefins are moved to the light olefin conversion device 6 through the seventh transmission pipeline 14.

[0063] The third separation device 5 is filled with an adsorbent (20% molecular sieve, 80% carbon; more than 85% of the pore size is 0.4-0.5 nm). After the fourth mixed gas enters the third separation device 5 through the eighth transmission pipeline 11, the C2-C4 olefins / alkanes therein are pressure-swing adsorbed and separated from other gases (H2, CO, CO2, CH4).

[0064] When the third separation device 5 includes a plurality of third separation sub-devices arranged in parallel, after one of the third separation sub-devices is saturated with adsorption, the third transmission pipeline 11 is controlled to pass into another first separation device to continue adsorption, and the saturated third separation sub-device is desorbed. Specifically, the pressure in the saturated third separation sub-device is regulated to 0.08MPa, and the C2 and above hydrocarbons desorbed by reduced pressure are discharged from the third separation device 5 through the ninth transmission pipeline 12 for collection, and other small molecule gases (H2, CO, CO2, CH4) are discharged from the third separation device 5 through the third outlet 20. After the desorption, the third separation sub-device can be pressure-regulated (pressurized as needed to make the pressure in the third separation sub-device after desorption compatible with the pressure in the eighth transmission pipeline 11), and participate in the adsorption link of C2-C4 hydrocarbon gas again.

[0065] The C5-C7 alkanes / olefins transferred to the light olefin conversion unit 6 are heated to 10 % on a metal-molecular sieve-based catalyst with a low acid content (the metal is 0.05% zinc, 0.05% copper. The molecular sieve is 5% ZSM-22, 95% ZSM-11; the acid content on the catalyst surface is 10 -5 mmol / g (which is 0.01% of the acid amount of hydrogen ZSM-5 (silicon-aluminum ratio 120, acid amount of 0.1 mmol / g)), and at 450-480°C, C5-C7 olefins / alkanes are converted into C2-C4 olefins and a small amount of aromatics. After the product is cooled, the obtained olefin product is collected through the tenth transmission pipeline 13 and combined with the logistics of the ninth transmission pipeline 12; the aromatic product is collected through the eleventh transmission pipeline 16 and combined with the logistics of the third transmission pipeline 17.

[0066] Example 4 The synthesis gas (H2:CO ratio of 2.2:1) is introduced into the aromatics synthesis unit 1 through the first transmission pipeline 7, and a catalyst with an active site of metal oxide-molecular sieve (the oxide is gallium oxide and the molecular sieve is ZSM-11) is used; the temperature of the aromatics synthesis unit 1 is controlled to be 350-380°C and the pressure is 6.1 MPa. The synthesis gas is catalytically converted into aromatics, wherein the CO single-pass conversion rate is 60% and the aromatics selectivity (hydrocarbon base) is 90%.

[0067] After the reaction, the first mixed gas containing aromatics (synthesis gas, CO2, water, aromatics, and a small amount of alkanes) obtained by the aromatics synthesis unit 1 enters the first separation unit 2 through the second transmission pipeline 8. At 0°C and 6.05 MPa, the aromatics and water vapor are liquefied and separated from other gases, wherein the generated water is discharged through the first outlet 18; the liquefied aromatics are discharged as products through the third transmission pipeline 17; the remaining gas is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes, which enters the olefin synthesis unit 3 through the fourth transmission pipeline 9.

[0068] Another stream of fresh synthesis gas (with a ratio of H2 to CO of 1.5:1 and a flow rate of 10 times the volume flow rate of the second mixed gas) is introduced into the olefin synthesis unit 3 from the fifth transmission pipeline 19, and the temperature is controlled at 350°C and the pressure is 6 MPa. Using a catalyst with metal carbides as active sites (the metal carbides are 70% iron carbide, 10% cobalt carbide, and 20% nickel carbide), olefin conversion reaction is carried out to obtain C1-C 10 The third mixed gas of hydrocarbons, in which the CO single-pass conversion rate is 98%, and the hydrocarbon products are C1-C 10 , olefin selectivity (hydrocarbon group) is 80%. C2-C4 olefin (olefin group) is 65%. The third mixed gas enters the second separation device 4 through the sixth transmission pipeline 10.

[0069] The third mixed gas entering the second separation device 4 is at -35°C and 5.9 MPa, and water and C5-C 10 The alkane / olefin is separated as a liquid, and a fourth mixed gas containing inorganic gas and C1-C4 hydrocarbons remains; wherein the generated water is discharged through the second outlet 15; the liquefied C5-C 10 The alkanes / olefins are moved to the light olefin conversion unit 6 through the seventh transfer pipeline 14 .

[0070] The third separation device 5 is filled with an adsorbent (carbon; more than 85% of the pore size is 0.4-0.5 nm). After the fourth mixed gas enters the third separation device 5 through the eighth transmission pipeline 11, the C2-C4 olefins / alkanes therein are pressure-swing adsorbed and separated from other gases (H2, CO, CO2, CH4).

[0071] When the third separation device 5 includes a plurality of third separation sub-devices arranged in parallel, after one of the third separation sub-devices is saturated with adsorption, the third transmission pipeline 11 is controlled to pass into another first separation device to continue adsorption, and the saturated third separation sub-device is desorbed. Specifically, the pressure in the saturated third separation sub-device is regulated to 1MPa, and the C2 and above hydrocarbons desorbed by reduced pressure are discharged from the third separation device 5 through the ninth transmission pipeline 12 for collection, and other small molecule gases (H2, CO, CO2, CH4) are discharged from the third separation device 5 through the third outlet 20. After the desorption, the third separation sub-device can be pressure-regulated (pressurized as needed to make the pressure in the third separation sub-device after desorption compatible with the pressure in the eighth transmission pipeline 11), and participate in the adsorption link of C2-C4 hydrocarbon gas again.

[0072] The C5-C 10Alkanes / olefins on metal-molecular sieve-based catalysts with low acid content (the metal is gallium, with a content of 0.001%. The molecular sieves are 45% ZSM-5, 35% ZSM-11, and 20% ZSM-22; the acid content on the catalyst surface is 10 -4 mmol / g (0.01% of the acid content of hydrogen-type ZSM-5 (Si-Al ratio 120, acid content 1 mmol / g)), and at 600 °C, C5-C 10 Olefins / alkanes are converted into C2-C4 olefins and a small amount of aromatics. After the products are cooled, the obtained olefin products are collected through the tenth transmission pipeline 13 and combined with the logistics of the ninth transmission pipeline 12; the aromatic products are collected through the eleventh transmission pipeline 16 and combined with the logistics of the third transmission pipeline 17.

[0073] Example 5 The synthesis gas (H2:CO ratio of 1.9:1) is introduced into the aromatics synthesis unit 1 through the first transmission pipeline 7, and a catalyst with an active site of metal oxide-molecular sieve (the oxide is germanium oxide and the molecular sieve is ZSM-5) is used; the temperature of the aromatics synthesis unit 1 is controlled to be 270-290°C and the pressure is 5.1 MPa. The synthesis gas is catalytically converted into aromatics, wherein the CO single-pass conversion rate is 49% and the aromatics selectivity (hydrocarbon base) is 78%.

[0074] After the reaction, the first mixed gas containing aromatics (synthesis gas, CO2, water, aromatics, and a small amount of alkanes) obtained by the aromatics synthesis unit 1 enters the first separation unit 2 through the second transmission pipeline 8. At -10°C and 5.05MPa, the aromatics and water vapor are liquefied and separated from other gases, wherein the generated water is discharged through the first outlet 18; the liquefied aromatics are discharged as products through the third transmission pipeline 17; the remaining gas is a second mixed gas composed of unreacted synthesis gas, CO2 and a small amount of alkanes, which enters the olefin synthesis unit 3 through the fourth transmission pipeline 9.

[0075] Another stream of fresh synthesis gas (with a ratio of H2 to CO of 1.9:1 and a flow rate of 6 times the volume flow rate of the second mixed gas) is introduced into the olefin synthesis unit 3 from the fifth transmission pipeline 19, and the temperature is controlled to be 330-346°C and the pressure is 5 MPa. Using a catalyst with metal carbide as the active site (the metal carbide is 10% cobalt carbide and 90% iron carbide), olefin conversion reaction is carried out to obtain C1-C 10 The third mixed gas of hydrocarbons, in which the CO single-pass conversion rate is 92%, and the hydrocarbon products are C1-C 10 The olefin selectivity (hydrocarbon group) is 79%. The C2-C4 olefin (olefin group) is 81.4%. The third mixed gas enters the second separation device 4 through the sixth transmission pipeline 10.

[0076] The third mixed gas entering the second separation device 4 is at -50°C and 4.8 MPa, and water and C5-C 10 The alkane / olefin is separated as a liquid, and a fourth mixed gas containing inorganic gas and C1-C4 hydrocarbons remains; wherein the generated water is discharged through the second outlet 15; the liquefied C5-C 10 The alkanes / olefins are moved to the light olefin conversion unit 6 through the seventh transfer pipeline 14 .

[0077] The third separation device 5 is filled with an adsorbent (molecular sieve; more than 85% of the pore size is 0.4-0.5 nm). After the fourth mixed gas enters the third separation device 5 through the eighth transmission pipeline 11, the C2-C4 olefins / alkanes therein are pressure-swing adsorbed and separated from other gases (H2, CO, CO2, CH4).

[0078] When the third separation device 5 includes a plurality of third separation sub-devices arranged in parallel, after one of the third separation sub-devices is saturated with adsorption, the third transmission pipeline 11 is controlled to pass into another first separation device to continue adsorption, and the saturated third separation sub-device is desorbed. Specifically, the pressure in the saturated third separation sub-device is regulated to 0.2MPa, and the C2 and above hydrocarbons desorbed by reduced pressure are discharged from the third separation device 5 through the ninth transmission pipeline 12 for collection, and other small molecule gases (H2, CO, CO2, CH4) are discharged from the third separation device 5 through the third outlet 20. After the desorption, the third separation sub-device can be pressure-regulated (pressurized as needed to make the pressure in the third separation sub-device after desorption compatible with the pressure in the eighth transmission pipeline 11), and participate in the adsorption link of C2-C4 hydrocarbon gas again.

[0079] The C5-C 10 Alkanes / olefins are reacted with molecular sieves (5% ZSM-22, 95% ZSM-5) at 550-580℃. 10 Olefins / alkanes are converted into C2-C4 olefins and a small amount of aromatics. After the products are cooled, the obtained olefin products are collected through the tenth transmission pipeline 13 and combined with the logistics of the ninth transmission pipeline 12; the aromatic products are collected through the eleventh transmission pipeline 16 and combined with the logistics of the third transmission pipeline 17.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0081] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

[0082] The above is a detailed introduction to the system and method for the joint preparation of aromatics and olefins from synthesis gas provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A system for preparing aromatics and olefins from synthesis gas, characterized in that: include: Aromatics synthesis unit, olefin synthesis unit, light olefin conversion unit and multiple separation units; among which, The aromatics synthesis unit, the first separation unit, the olefin synthesis unit, the second separation unit and the third separation unit are connected in series in sequence, and the second separation unit is connected to the light olefin conversion unit; The aromatics synthesis device is used to catalytically convert synthesis gas into aromatics to obtain a first mixed gas containing aromatics; The first separation device is used to receive and cool the first mixed gas to liquefy the aromatic hydrocarbons and water vapor therein, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; The olefin synthesis device is used to receive the second mixed gas and the fresh synthesis gas, and perform olefin conversion reaction to obtain C1-C 10 a third mixed gas of hydrocarbons; The second separation device is used to receive and cool the third mixed gas, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; The third separation device is used to receive the fourth mixed gas and perform adsorption to separate C2-C4 hydrocarbons from small molecule gases H2, CO, CO2 and CH4; The light olefin conversion unit is used to receive the liquefied C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics.

2. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The aromatics synthesis device is filled with a metal oxide-molecular sieve catalyst; wherein, The metal oxide includes: one or more of zinc oxide, gallium oxide and germanium oxide; The molecular sieve includes one or more of ZSM-5, ZSM-11, and ZSM-22; The operating temperature of the aromatics synthesis unit is 250-380°C, and the operating pressure is 2.1-6.1MPa.

3. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The first separation device cools the first mixed gas to liquefy the aromatic hydrocarbons and water vapor therein by setting a first temperature control device; wherein, The temperature control range of the first temperature control device includes -20~0 ℃.

4. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The olefin synthesis device is filled with a catalyst whose active component is a metal carbide; wherein the metal carbide includes: one or more of iron carbide, cobalt carbide and nickel carbide; The operating temperature of the olefin synthesis unit is 250-380°C.

5. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The second separation device cools the third mixed gas by setting a second temperature control device so that the H2O, C5-C 10 The purpose of hydrocarbon liquefaction; wherein, The temperature control range of the second temperature control device includes -60~-35°C.

6. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The third separation device comprises a pressure sub-control device and a plurality of third separation sub-devices arranged in parallel, and the plurality of third separation sub-devices are filled with adsorbent; wherein, The adsorbent is an inorganic oxide, a molecular sieve or carbon, and the pore size of the adsorbent meets the requirement that more than 85% of the pore size is 0.4-0.5 nm.

7. The system for preparing aromatics and olefins from synthesis gas according to claim 1, characterized in that: The light olefin conversion unit is filled with a molecular sieve or a metal-molecular sieve-based catalyst; wherein the metal is one or more of gallium, zinc, copper and manganese, and the molecular sieve is ZSM-5, ZSM-22 or ZSM-11; The acid amount of the molecular sieve and the metal-molecular sieve-based catalyst is 10 -5 -10 -3 mmol / g; The light olefin conversion unit is provided with a third temperature control device, and the temperature control range of the third temperature control device includes 450-600°C.

8. A method for preparing aromatics and olefins from synthesis gas, characterized in that: The method is applicable to the system for preparing aromatics and olefins from synthesis gas as claimed in any one of claims 1 to 7, and the method comprises: Filling the reaction zone of the aromatics synthesis unit with a metal oxide-molecular sieve catalyst, filling the reaction zone of the olefin synthesis unit with a catalyst whose active component is a metal carbide, filling the reaction zone of the light olefin conversion unit with a molecular sieve or a metal-molecular sieve-based catalyst; filling the third separation unit with an adsorbent; Controlling the working pressure of the aromatics synthesis unit to 2.1-6.1 MPa and the working temperature to 250-380°C, controlling the working temperature of the first separation unit to -20~0°C, controlling the working temperature of the olefin synthesis unit to 250-380°C, controlling the working temperature of the second separation unit to -60~-35°C, and controlling the working temperature of the light olefin conversion unit to 450-600°C; Passing synthesis gas with a H2 / CO ratio of 1.5:1 to 2.2:1 into the aromatics synthesis device to convert aromatics to obtain a first mixed gas containing aromatics; Passing the first mixed gas into the first separation device to liquefy the aromatic hydrocarbons and water vapor in the first mixed gas, and the remaining second mixed gas containing unreacted synthesis gas, CO2 and a small amount of alkanes; The second mixed gas is introduced into an olefin synthesis unit as a reaction gas, and fresh synthesis gas is further added to carry out olefin conversion reaction to obtain a C1-C 10 a third mixed gas of hydrocarbons; The third mixed gas is introduced into the second separation device, so that the water vapor and C5-C 10 The hydrocarbons are liquefied, and a fourth mixed gas containing inorganic gases and C1-C4 hydrocarbons remains; Passing the fourth mixed gas into a third separation device, so that the adsorbent in the third separation device adsorbs C2-C4 hydrocarbons in the fourth mixed gas, and the remaining small molecule gas containing H2, CO, CO2 and CH4; The liquefied C5-C 10 The hydrocarbons are introduced into the light olefin conversion unit to undergo a light olefin conversion reaction to obtain C5-C 10 Hydrocarbons are converted into C2-C4 olefins and a small amount of aromatics; The C2-C4 olefins generated in the light olefin conversion unit and the C2-C4 hydrocarbons obtained by adsorption in the third separation unit are combined and collected, and the aromatics generated in the light olefin conversion unit and the aromatics obtained by liquefaction in the first separation unit are combined and collected.

9. The method for preparing aromatics and olefins from synthesis gas according to claim 8, characterized in that: In the olefin synthesis device, the volume flow rate of the introduced fresh synthesis gas is 3-10 times that of the introduced second mixed gas.

10. The method for preparing aromatics and olefins from synthesis gas according to claim 8, characterized in that: In the aromatics synthesis unit, the CO single-pass conversion rate is 40-60%, and the aromatics selectivity is 75%-90% based on the hydrocarbon base; In the olefin synthesis device, the CO single-pass conversion rate is 90-98%; Based on the hydrocarbon group, the olefin selectivity is 65%-80%, among which, based on the olefin group, the C2-C4 olefin is 65-85%.

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