Single-tube test device and method for directly producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide

Abstract

A single-tube test device and method for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide relates to the technical field of gasoline production chemical process, comprising a gas-to-gas heat exchanger, a heater, a single-tube reactor, a cooling condenser, a gas-liquid separator I, an oil-water separator, a circulating compressor, a heat transfer oil circulating pump, a heat transfer oil cooler, a gas-liquid separator II, an expansion tank, a raw material hydrogen regulating valve, a raw material carbon dioxide regulating valve, a pressure reducing valve I, a regulating valve I, a pressure reducing valve II, a regulating valve II, a regulating valve III, a start-up heater, an iron-based tubing section, an iron-based insulation section, a molecular sieve insulation section, a tubing section shell, a tubing section reaction tube, and an electric heating belt. The scheme is suitable for a reactor with two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst, which are loaded in layers. The reactor type is suitable for reaction conditions in which the reaction thermodynamic properties and the optimal reaction temperature of the reaction medium in which the two catalysts are located are different.

Description

Technical field:

[0001] The invention relates to the technical field of gasoline production chemical process, in particular to a single-tube test device and method for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide. Background technology:

[0002] In recent years, with the rapid development of industry, fossil energy has become increasingly depleted. The large-scale use of fossil energy has led to the emission of a large amount of carbon dioxide, and the global environmental problems caused by this have attracted widespread attention from countries around the world. By chemically converting carbon dioxide into synthesis gas or other hydrocarbons, not only can carbon dioxide be used as a resource, but it can also reduce the "greenhouse effect" caused by carbon dioxide.

[0003] Although the greenhouse effect of carbon dioxide causes global warming and climate change, it is widely used as an industrial raw material. Converting carbon dioxide into liquid fuels and high-value-added chemicals through chemical conversion methods has become a research hotspot at home and abroad recently. This process can not only realize the resource utilization of carbon dioxide, but also reduce the "greenhouse effect" caused by carbon dioxide.

[0004] However, carbon dioxide molecules are very stable, and their activation and selective conversion are extremely challenging problems. Due to its slow adsorption and reaction rate on the catalyst surface and poor chain growth ability, its hydrogenation products are concentrated in low-carbon compounds such as methane, methanol, and formic acid. If this process can be used to selectively produce high-carbon hydrocarbons such as oils, olefins or aromatics with higher carbon chains and higher added value, it will have an important and far-reaching impact on traditional coal and natural gas chemical routes.

[0005] At present, there is no single-tube test device and method for directly producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide in public data, especially a single-tube test device and method suitable for a reactor layered with two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst. The reaction thermodynamic properties of the reaction medium in which these two catalysts are located and the applicable optimal reaction temperature conditions are different. Summary of the invention:

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art, and without targeting the defects of a single-tube test device and method for producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide in a reactor using two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst, a single-tube test device and method for directly producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide are provided.

[0007] The present invention is achieved through the following technical solutions:

[0008] A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide, characterized in that it comprises a gas-to-gas heat exchanger, a heater, a single-tube reactor, a cooling condenser, a gas-liquid separator I, an oil-water separator, a circulating compressor, a heat transfer oil circulating pump, a heat transfer oil cooler, a gas-liquid separator II, an expansion tank, a raw material hydrogen regulating valve, a raw material carbon dioxide regulating valve, a pressure reducing valve I, a regulating valve I, a pressure reducing valve II, a regulating valve II, a regulating valve III, a start-up heater, an iron-based tubing section, an iron-based insulation section, a molecular sieve insulation section, a tubing section shell, a tubing section reaction tube, and an electric heating belt;

[0009] The outlet pipeline of the raw carbon dioxide regulating valve is connected to the raw hydrogen pipeline of the outlet of the raw hydrogen regulating valve, the mixed raw carbon dioxide and raw hydrogen pipelines are connected to the cold side inlet pipeline of the gas-to-gas heat exchanger, the hot side outlet pipeline of the gas-to-gas heat exchanger is connected to the cold side inlet of the heater, the hot side outlet pipeline of the heater is connected to the top inlet of the single-tube reactor, the bottom outlet pipeline of the single-tube reactor is connected to the hot side inlet of the gas-to-gas heat exchanger, the cold side outlet pipeline of the gas-to-gas heat exchanger is connected to the hot side inlet of the cooling condenser, the cold side outlet pipeline of the cooling condenser is connected to the inlet of the gas-liquid separator I, and the bottom liquid phase outlet pipeline of the gas-liquid separator I is regulated and controlled by the regulating valve I and then connected to the inlet of the oil-water separator;

[0010] The top gas phase outlet of the gas-liquid separator I is divided into two paths, one of which is connected to the inlet of the circulating compressor, and the outlet pipeline of the circulating compressor is connected to the pipeline of the raw carbon dioxide and hydrogen mixed gas; the other is connected to the inlet pipeline of the pressure reducing valve I, and the gas pipeline after the pressure reduction at the outlet of the pressure reducing valve I is connected to the tail gas main pipe;

[0011] The top gas phase outlet pipeline of the oil-water separator is connected to the inlet of the pressure reducing valve II;

[0012] The bottom pipe opening of the expansion tank is connected with the top pipe opening of the gas-liquid separator II through a pipeline; the bottom outlet pipeline of the gas-liquid separator II is connected with the inlet of the heat transfer oil pump; the outlet of the heat transfer oil pump is divided into two paths, one of which is connected with the inlet of the regulating valve II, and the outlet pipeline of the regulating valve II is connected with the cold side inlet of the start-up heater; the other path is connected with the hot side inlet pipeline of the heat transfer oil cooler, and the outlet pipeline of the heat transfer oil cooled by the heat transfer oil cooler is connected with the outlet pipeline of the regulating valve II; the hot side outlet of the start-up heater is connected with the heat transfer oil inlet below the shell of the tube section of the single-tube reactor; the heat transfer oil outlet pipeline above the shell of the tube section of the single-tube reactor is connected with the inlet of the gas-liquid separator II.

[0013] In another aspect of the present invention, the single tube reactor is composed of an iron-based tube section, an iron-based insulation section and a molecular sieve insulation section from top to bottom, and electric heating tapes are wound around the outer walls of the iron-based tube section, the iron-based insulation section and the molecular sieve insulation section.

[0014] In another aspect of the present invention, the heater and the start-up heater are electrically heated or steam heated.

[0015] In another aspect of the present invention, it also includes a cryogenic refrigerator and a gas-liquid separator III, wherein the top gas phase outlet pipeline of the gas-liquid separator I is connected to the hot side inlet of the cryogenic refrigerator, the cold side outlet of the cryogenic refrigerator is connected to the inlet of the gas-liquid separator III, and the bottom liquid phase outlet pipeline of the gas-liquid separator III is connected to the inlet of the oil-water separator after being adjusted and controlled by the regulating valve III; the top gas phase outlet of the gas-liquid separator III is divided into two paths, one of which is connected to the inlet of the circulating compressor, and the other is connected to the inlet pipeline of the pressure reducing valve I.

[0016] In another aspect of the present invention, it also includes a cryogenic refrigerator and a gas-liquid separator III, the circulating compressor is arranged on the top gas phase outlet pipeline of the gas-liquid separator I, the outlet pipeline of the circulating compressor is connected to the hot side inlet of the cryogenic refrigerator, the cold side outlet of the cryogenic refrigerator is connected to the inlet of the gas-liquid separator III, and the bottom liquid phase outlet pipeline of the gas-liquid separator III is connected to the inlet of the oil-water separator after being adjusted and controlled by the regulating valve III; the top gas phase outlet of the gas-liquid separator III is divided into two paths, one of which is connected to the raw carbon dioxide and hydrogen mixed gas pipeline, and the other is connected to the inlet pipeline of the pressure reducing valve I.

[0017] A single-tube test method for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide, characterized in that it comprises the following steps:

[0018] Send the heat transfer oil to the expansion tank, wait until the heat transfer oil circulation system is full of heat transfer oil and the heat transfer oil level in the expansion tank is at a suitable position, and then start the heat transfer oil circulation pump;

[0019] Turn on the start-up heater and the electric heating tape on the outer wall of the iron-based tube section, iron-based insulation section and molecular sieve insulation section of the single-tube reactor to heat the heat transfer oil circulation system to the required set temperature;

[0020] Fresh raw carbon dioxide with a temperature of 10-50°C and a pressure of 1.5-7.0Mpa is introduced;

[0021] Fresh raw hydrogen with a temperature of 10-50°C and a pressure of 1.5-7.0Mpa is introduced;

[0022] The raw hydrogen and raw carbon dioxide are heated in turn by the gas-to-gas heat exchanger, and the heater further heats and heats the mixed heating gas. The temperature of the heated mixed heating gas is 250-450°C. During the heating process of the heating gas, the heat exchange load of the gas-to-gas heat exchanger gradually increases.

[0023] The mixed heated gas is introduced into the single tube reactor, and passes through the fixed bed catalyst bed of the iron-based tube section, the iron-based insulation section and the molecular sieve insulation section from top to bottom, and a chemical reaction occurs to obtain a reaction mixed gas. The reaction temperature is 250-500°C, the pressure is 1.0-6.0Mpa, and the general formula of the overall reaction equation is: nCO 2 +(n~6n)H 2 =n 1 CO+n 2 CH 4 +(n 3 C 2 ~n 5 C 4 )+(n 6 C 5 ~n 12 C 11 )+n 13 H 2 O, the reaction catalyst is an iron-based / molecular sieve (Na-Fe3O4 / HZSM-5) multifunctional composite catalyst;

[0024] The start-up heater in the heat transfer oil circulation system is turned off, and the heat transfer oil cooler is switched on to control the temperature of the heat transfer oil circulation system, and further control the temperature of the iron-based catalyst bed in the reaction tube of the tube section of the single tube reactor;

[0025] The reaction mixture is cooled and condensed in turn through the gas-to-gas heat exchanger and the cooling condenser from the bottom of the single-tube reactor to obtain a low-temperature mixed gas / liquid after cooling and partial condensation. The temperature of the low-temperature mixed gas / liquid is -30 to 10°C.

[0026] The low-temperature mixed gas / liquid is separated into gas and liquid by a gas-liquid separator I, and the pressure of the gas-liquid separator I is 1.0-6.0 MPa; a part of the gas is directly recycled and combined with the fresh raw gas after being pressurized by a circulating compressor, and the circulating gas temperature is 0-60°C and the pressure is 1.5-7.0 MPa. The other part of the gas is decompressed by a pressure reducing valve I and discharged as part of the tail gas.

[0027] In another aspect of the present invention, the liquid separated by the gas-liquid separator I is regulated by the regulating valve I to control its flow rate and enter the oil-water separator. The pressure of the oil-water separator is 0.5-3.0 MPa. The small amount of separated gas is decompressed by the pressure reducing valve II and then discharged as tail gas; the separated liquid crude gasoline and waste water are continuously sent out.

[0028] In another aspect of the present invention, the gas separated by the gas-liquid separator I enters a cryogenic refrigerator for further cooling and condensation, the outlet temperature of the cryogenic refrigerator is -40 to 5°C, the low-temperature mixed gas / liquid at the outlet of the cryogenic refrigerator is separated into gas and liquid by a gas-liquid separator III, and the pressure of the gas-liquid separator III is 1.0 to 6.0 MPa; a part of the gas is directly recycled and reused, and is combined with the fresh raw gas after being pressurized by a circulating compressor, the circulating gas temperature is -20 to 50°C, and the pressure is 1.5 to 7.0 MPa, and the other part of the gas is depressurized by a pressure reducing valve I and discharged as part of the tail gas.

[0029] In another aspect of the present invention, a circulating compressor is disposed on a pipeline between the top gas phase outlet of the gas-liquid separator I and the hot side inlet of the cryogenic cooler.

[0030] The beneficial effects of the present invention are:

[0031] (1) This scheme provides a single-tube experimental device and method for producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide using a reactor loaded with two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst, in layers. The reactor type is suitable for reaction conditions where the reaction thermodynamic properties and optimal reaction temperatures of the reaction medium in which the two catalysts are located are different;

[0032] (2) In this scheme, most of the iron-based catalyst beds with large reaction heat release are loaded above the single-tube reactor in an isothermal tubular fixed bed manner, and a small amount of iron-based catalyst beds and all molecular sieve catalyst beds are loaded in sequence at the outlet below the isothermal tubular fixed bed reactor, which not only ensures the balance and control between the heat release and heat transfer in the iron-based catalyst bed, but also satisfies the reaction temperature condition requirement that the inlet of the molecular sieve catalyst bed with less reaction heat release has a higher reaction temperature value than the outlet temperature of the isothermal tubular reactor bed;

[0033] (3) The temperature of the central reaction bed of the isothermal single-tube reactor of this scheme is mainly controlled by adjusting the temperature and circulation volume of the heat transfer oil in the casing. The corresponding heat calculation can be performed based on the specific heat of the heat transfer oil and its temperature in and out of the casing, the flow rate in the tube and the temperature of the reaction medium in and out of the reaction tube in the catalyst bed, as well as the heat transfer area and the reactor material. The calculation results can be generalized and applied to the design of industrial-scale reactors with high-pressure steam attached to the shell side, which greatly reduces the difficulties in the design and operation of the single-tube experimental device caused by the small scale of the single tube and the use of high-pressure steam medium on the shell side. Description of the drawings:

[0034] Figure 1 This is a structural diagram of Example 1 of the present invention.

[0035] Figure 2 This is a structural diagram of Example 2 of the present invention.

[0036] Figure 3 This is a structural diagram of Example 3 of the present invention.

[0037] Figure 4 It is a schematic diagram of the structure of a single tube reactor in the present invention.

[0038] In the accompanying drawings: 1. gas-gas heat exchanger, 2. heater, 3. single-tube reactor, 4. cooling condenser, 5. gas-liquid separator I, 6. oil-water separator, 7. circulating compressor, 8. heat transfer oil circulating pump, 9. heat transfer oil cooler, 10. gas-liquid separator II, 11. expansion tank, 12. raw material hydrogen regulating valve, 13. raw material carbon dioxide regulating valve, 14. pressure reducing valve I, 15. regulating valve I, 16. pressure reducing valve II, 17. regulating valve II, 18. deep freezer, 19. gas-liquid separator III, 20. regulating valve III, 21. start-up heater, 22. iron-based column and tube section, 23. iron-based insulation section, 24. molecular sieve insulation section, 25. column and tube section shell, 26. column and tube section reaction tube, 27. electric heating belt, 28. heat transfer oil, 29. raw material carbon dioxide, 30. raw material hydrogen, 31. tail gas, 32. crude gasoline, 33. waste water. Specific implementation method:

[0039] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings and embodiments:

[0040] In the description of the present invention, it is necessary to understand that the description indicating the orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Example 1

[0043] A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide, comprising a gas-gas heat exchanger 1, a heater 2, a single-tube reactor 3, a cooling condenser 4, a gas-liquid separator I 5, an oil-water separator 6, a circulating compressor 7, a heat transfer oil circulating pump 8, a heat transfer oil cooler 9, a gas-liquid separator II 10, an expansion tank 11, a raw material hydrogen regulating valve 12, a raw material carbon dioxide regulating valve 13, a pressure reducing valve I14, a regulating valve I15, a pressure reducing valve II 16, a regulating valve II 17, a start-up heater 21, an iron-based tubing section 22, an iron-based insulation section 23, a molecular sieve insulation section 24, a tubing section shell 25, a tubing section reaction tube 26, and an electric heating belt 27;

[0044] The inlet pipeline of the raw carbon dioxide regulating valve 13 is connected to the raw carbon dioxide, the inlet pipeline of the raw hydrogen regulating valve 12 is connected to the raw hydrogen, the outlet pipeline of the raw carbon dioxide regulating valve 13 is connected to the raw hydrogen pipeline of the outlet of the raw hydrogen regulating valve 12, the mixed raw carbon dioxide and raw hydrogen pipelines are connected to the cold side inlet pipeline of the gas-to-gas heat exchanger 1, the hot side outlet pipeline of the gas-to-gas heat exchanger 1 is connected to the cold side inlet of the heater 2, the hot side outlet pipeline of the heater 2 is connected to the top inlet of the single-tube reactor 3, the bottom outlet pipeline of the single-tube reactor 3 is connected to the hot side inlet of the gas-to-gas heat exchanger 1, the cold side outlet pipeline of the gas-to-gas heat exchanger 1 is connected to the hot side inlet of the cooling condenser 4, the cold side outlet pipeline of the cooling condenser 4 is connected to the inlet of the gas-liquid separator 15, and the bottom liquid phase outlet pipeline of the gas-liquid separator 15 is regulated and controlled by the regulating valve 115 and then connected to the inlet of the oil-water separator 6;

[0045] The top gas phase outlet of the gas-liquid separator 15 is divided into two paths, one of which is connected to the inlet of the circulating compressor 7, and the outlet pipeline of the circulating compressor 7 is connected to the pipeline of the raw carbon dioxide and hydrogen mixed gas; the other is connected to the inlet pipeline of the pressure reducing valve 114, and the gas pipeline after the pressure reduction at the outlet of the pressure reducing valve 114 is connected to the tail gas main pipe;

[0046] The gas phase outlet pipeline at the top of the oil-water separator 6 is connected to the inlet of the pressure reducing valve II 16, and the outlet of the pressure reducing valve II 16 continuously discharges tail gas after pressure reduction, the oil phase outlet pipeline of the oil-water separator 6 continuously discharges crude gasoline product, and the bottom water phase outlet pipeline of the oil-water separation tank 6 continuously discharges waste water;

[0047] The intermittently replenished heat transfer oil is connected to the heat transfer oil inlet at the top of the expansion tank 11 through a pipeline, and the bottom pipe port of the expansion tank 11 is connected to the top pipe port of the gas-liquid separator II 10 through a pipeline, which is used to replenish the heat transfer oil of the circulating heat transfer oil system and also used to discharge the gas phase components generated in the circulating heat transfer oil system; the bottom outlet pipeline of the gas-liquid separator II 10 is connected to the inlet of the heat transfer oil pump 8; the outlet of the heat transfer oil pump 8 is divided into two paths, one of which is connected to the inlet of the regulating valve II 17, and the outlet pipeline of the regulating valve II 17 is connected to the cold side inlet of the start-up heater 21; the other path is connected to the hot side inlet pipeline of the heat transfer oil cooler 9, and the heat transfer oil outlet pipeline cooled by the heat transfer oil cooler 9 is connected to the outlet pipeline of the regulating valve II 17; the hot side outlet of the start-up heater 21 is connected to the heat transfer oil inlet below the shell 25 of the tube section of the single tube reactor 3; the heat transfer oil outlet pipeline above the shell 25 of the tube section of the single tube reactor 3 is connected to the inlet of the gas-liquid separator II 10;

[0048] The single tube reactor 3 is composed of an iron-based tube section 22, an iron-based insulation section 23 and a molecular sieve insulation section 24 from top to bottom. Electric heating tapes 27 are wound around the outer walls of the iron-based tube section 22, the iron-based insulation section 23 and the molecular sieve insulation section 24 to maintain the tube section shell 25 and the outer walls of the iron-based insulation section 23 and the molecular sieve insulation section 24 at a constant temperature to compensate for the heat dissipation to the surrounding environment.

[0049] The heater 2 and the start-up heater 21 can be heated by electricity or steam.

[0050] The single-tube test device for directly producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide comprises the following specific operating steps when used:

[0051] Step (1), delivering the heat transfer oil to the expansion tank 11, and when the heat transfer oil circulation system is filled with the heat transfer oil and the heat transfer oil level in the expansion tank 11 is at a suitable position, start the heat transfer oil circulation pump 8;

[0052] Step (2), turning on the start-up heater 21 and the electric heating tape on the outer wall of the iron-based tube section 22, the iron-based insulation section 23 and the molecular sieve insulation section 24 of the single tube reactor 3, heating the heat transfer oil circulation system to the required set temperature;

[0053] Step (3), introducing fresh raw carbon dioxide at a temperature of 10 to 50° C. and a pressure of 1.5 to 7.0 MPa;

[0054] Step (4), introducing fresh raw hydrogen gas at a temperature of 10 to 50° C. and a pressure of 1.5 to 7.0 MPa;

[0055] Step (5), the raw hydrogen and raw carbon dioxide are heated in turn by gas-to-gas heat exchanger 1, and further heated by heater 2. The temperature of the heated mixed heating gas is 250-450° C., and the heat exchange load of gas-to-gas heat exchanger 1 gradually increases during the heating process;

[0056] Step (6), the mixed heated gas is introduced into the single tube reactor 3, and passes through the fixed bed catalyst bed of the iron-based tube section 22, the iron-based insulation section 23 and the molecular sieve insulation section 24 from top to bottom, and a chemical reaction occurs to obtain a reaction mixed gas. The reaction temperature is 250-500° C., the pressure is 1.0-6.0 MPa, and the overall reaction equation is: nCO 2 +(n~6n)H 2 =n 1 CO+n 2 CH 4 +(n 3 C 2 ~n 5 C 4 )+(n 6 C 5 ~n 12 C 11 )+n 13 H 2 O, the reaction catalyst is an iron-based / molecular sieve (Na-Fe3O4 / HZSM-5) multifunctional composite catalyst;

[0057] Step (7), turning off the start-up heater 21 in the heat transfer oil circulation system and switching on the heat transfer oil cooler 9 to control the temperature of the heat transfer oil circulation system, and further controlling the temperature of the iron-based catalyst bed in the reaction tube 26 of the tube column section of the single tube reactor 3;

[0058] Step (8), the reaction mixture is cooled and condensed from the bottom of the single tube reactor 3 through the gas-to-gas heat exchanger 1 and the cooling condenser 4 in sequence to obtain a low-temperature mixed gas / liquid after cooling and partial condensation, wherein the temperature of the low-temperature mixed gas / liquid is -30 to 10°C;

[0059] Step (9), the low-temperature mixed gas / liquid is separated into gas and liquid by a gas-liquid separator I5, and the pressure of the gas-liquid separator I5 is 1.0-6.0 MPa; a part of the gas is directly recycled and reused, and is combined with the fresh raw gas after being pressurized by a circulating compressor 7, and the circulating gas temperature is 0-60° C. and the pressure is 1.5-7.0 MPa. The other part of the gas is decompressed by a pressure reducing valve I14 and discharged as part of the tail gas;

[0060] Step (10), the liquid separated by the gas-liquid separator I5 in step (9) is regulated by the regulating valve I15 to control its flow rate and enter the oil-water separator 6, the oil-water separator pressure is 0.5-3.0Mpa, and the small amount of gas separated is decompressed by the pressure reducing valve II16 and discharged as exhaust gas; the separated liquid crude gasoline and waste water are continuously sent out.

[0061] (1) This scheme provides a single-tube experimental device and method for producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide using a reactor loaded with two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst, in layers. The reactor type is suitable for reaction conditions where the reaction thermodynamic properties and optimal reaction temperatures of the reaction medium in which the two catalysts are located are different;

[0062] (2) In this scheme, most of the iron-based catalyst beds with large reaction heat release are loaded above the single-tube reactor in an isothermal tubular fixed bed manner, and a small amount of iron-based catalyst beds and all molecular sieve catalyst beds are loaded in sequence at the outlet below the isothermal tubular fixed bed reactor, which not only ensures the balance and control between the heat release and heat transfer in the iron-based catalyst bed, but also satisfies the reaction temperature condition requirement that the inlet of the molecular sieve catalyst bed with less reaction heat release has a higher reaction temperature value than the outlet temperature of the isothermal tubular reactor bed;

[0063] (3) The temperature of the central reaction bed of the isothermal single-tube reactor of this scheme is mainly controlled by adjusting the temperature and circulation volume of the heat transfer oil in the casing. The corresponding heat calculation can be performed based on the specific heat of the heat transfer oil and its temperature in and out of the casing, the flow rate in the tube and the temperature of the reaction medium in and out of the reaction tube in the catalyst bed, as well as the heat transfer area and the reactor material. The calculation results can be generalized and applied to the design of industrial-scale reactors with high-pressure steam attached to the shell side, which greatly reduces the difficulties in the design and operation of the single-tube experimental device caused by the small scale of the single tube and the use of high-pressure steam medium on the shell side.

[0064] Example 2

[0065] In this embodiment, the top gas phase outlet pipeline of the gas-liquid separator I 5 in Example 1 is connected to the hot side inlet of the cryogenic refrigerator 18, the cold side outlet of the cryogenic refrigerator 18 is connected to the inlet of the gas-liquid separator III 19, and the bottom liquid phase outlet pipeline of the gas-liquid separator III 19 is connected to the inlet of the oil-water separator 6 after being adjusted and controlled by the regulating valve III 20; the top gas phase outlet of the gas-liquid separator III 19 is divided into two paths, one of which is connected to the inlet of the circulating compressor 7, and the other is connected to the inlet pipeline of the pressure reducing valve I14.

[0066] Example 3

[0067] In this embodiment, the circulating compressor 7 in Example 2 is arranged on the top gas phase outlet pipe of the gas-liquid separator I 5. At this time, the outlet pipe of the circulating compressor 7 is connected to the hot side inlet of the cryogenic cooler 18.

[0068] Example 4

[0069] A single-tube test method for directly preparing gasoline fraction hydrocarbons by hydrogenating carbon dioxide comprises the following steps:

[0070] Step (1), delivering the heat transfer oil to the expansion tank 11, and when the heat transfer oil circulation system is filled with the heat transfer oil and the heat transfer oil level in the expansion tank 11 is at a suitable position, start the heat transfer oil circulation pump 8;

[0071] Step (2), turning on the start-up heater 21 and the electric heating tape on the outer wall of the iron-based tube section 22, the iron-based insulation section 23 and the molecular sieve insulation section 24 of the single tube reactor 3, heating the heat transfer oil circulation system to the required set temperature;

[0072] Step (3), introducing fresh raw carbon dioxide at a temperature of 10 to 50° C. and a pressure of 1.5 to 7.0 MPa;

[0073] Step (4), introducing fresh raw hydrogen gas at a temperature of 10 to 50° C. and a pressure of 1.5 to 7.0 MPa;

[0074] Step (5), the raw hydrogen and raw carbon dioxide are heated in turn by gas-to-gas heat exchanger 1, and further heated by heater 2. The temperature of the heated mixed heating gas is 250-450° C., and the heat exchange load of gas-to-gas heat exchanger 1 gradually increases during the heating process;

[0075] Step (6), the mixed heated gas is introduced into the single tube reactor 3, and passes through the fixed bed catalyst bed of the iron-based tube section 22, the iron-based insulation section 23 and the molecular sieve insulation section 24 from top to bottom, and a chemical reaction occurs to obtain a reaction mixed gas. The reaction temperature is 250-500° C., the pressure is 1.0-6.0 MPa, and the overall reaction equation is: nCO 2 +(n~6n)H 2 =n 1 CO+n 2 CH 4 +(n 3 C 2 ~n 5 C 4 )+(n 6 C 5 ~n 12 C 11 )+n 13 H 2O, the reaction catalyst is an iron-based / molecular sieve (Na-Fe3O4 / HZSM-5) multifunctional composite catalyst;

[0076] Step (7), turning off the start-up heater 21 in the heat transfer oil circulation system and switching on the heat transfer oil cooler 9 to control the temperature of the heat transfer oil circulation system, and further controlling the temperature of the iron-based catalyst bed in the reaction tube 26 of the tube column section of the single tube reactor 3;

[0077] Step (8), the reaction mixture is cooled and condensed from the bottom of the single tube reactor 3 through the gas-to-gas heat exchanger 1 and the cooling condenser 4 in sequence to obtain a low-temperature mixed gas / liquid after cooling and partial condensation, wherein the temperature of the low-temperature mixed gas / liquid is -30 to 10°C;

[0078] In step (9), the low-temperature mixed gas / liquid is separated into gas and liquid by a gas-liquid separator I5, and the pressure of the gas-liquid separator I5 is 1.0 to 6.0 MPa; a part of the gas is directly recycled and reused, and is combined with the fresh raw gas after being pressurized by a circulating compressor 7, and the circulating gas temperature is 0 to 60° C. and the pressure is 1.5 to 7.0 MPa. The other part of the gas is depressurized by a pressure reducing valve I14 and discharged as part of the tail gas.

[0079] The liquid separated by the gas-liquid separator I5 in step (9) is regulated by a regulating valve I15 to control its flow rate and enter the oil-water separator 6. The oil-water separator pressure is 0.5-3.0 MPa. The small amount of gas separated is decompressed by a pressure reducing valve II16 and then discharged as tail gas; the separated liquid crude gasoline and waste water are continuously sent out.

[0080] The gas separated by the gas-liquid separator I in the step (9) can also enter the cryogenic refrigerator 18 for further cooling and condensation. The outlet temperature of the cryogenic refrigerator 18 is -40 to 5°C. The low-temperature mixed gas / liquid at the outlet of the cryogenic refrigerator 18 is separated into gas and liquid by the gas-liquid separator III 19. The pressure of the gas-liquid separator III 5 is 1.0 to 6.0 MPa. A part of the gas is directly recycled and reused, and is combined with the fresh raw gas after being pressurized by the circulating compressor 7. The circulating gas temperature is -20 to 50°C and the pressure is 1.5 to 7.0 MPa. The other part of the gas is depressurized by the pressure reducing valve I14 and discharged as part of the tail gas.

[0081] The circulating compressor 7 can also be arranged on the pipeline between the top gas phase outlet of the gas-liquid separator I 5 and the hot side inlet of the deep cooler 18.

[0082] The beneficial effects of this single-tube test method for directly producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide are:

[0083] (1) This scheme provides a single-tube experimental device and method for producing gasoline fraction hydrocarbons by hydrogenating carbon dioxide using a reactor loaded with two multifunctional composite catalysts, an iron-based catalyst and a molecular sieve catalyst, in layers. The reactor type is suitable for reaction conditions where the reaction thermodynamic properties and optimal reaction temperatures of the reaction medium in which the two catalysts are located are different;

[0084] (2) In this scheme, most of the iron-based catalyst beds with large reaction heat release are loaded above the single-tube reactor in an isothermal tubular fixed bed manner, and a small amount of iron-based catalyst beds and all molecular sieve catalyst beds are loaded in sequence at the outlet below the isothermal tubular fixed bed reactor, which not only ensures the balance and control between the heat release and heat transfer in the iron-based catalyst bed, but also satisfies the reaction temperature condition requirement that the inlet of the molecular sieve catalyst bed with less reaction heat release has a higher reaction temperature value than the outlet temperature of the isothermal tubular reactor bed;

[0085] (3) The temperature of the central reaction bed of the isothermal single-tube reactor of this scheme is mainly controlled by adjusting the temperature and circulation volume of the heat transfer oil in the casing. The corresponding heat calculation can be performed based on the specific heat of the heat transfer oil and its temperature in and out of the casing, the flow rate in the tube and the temperature of the reaction medium in and out of the reaction tube in the catalyst bed, as well as the heat transfer area and the reactor material. The calculation results can be generalized and applied to the design of industrial-scale reactors with high-pressure steam attached to the shell side, which greatly reduces the difficulties in the design and operation of the single-tube experimental device caused by the small scale of the single tube and the use of high-pressure steam medium on the shell side.

[0086] In conclusion, the above is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the patent of the present invention.

Claims

1. A single-tube test device for directly producing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide. Its characteristics are: It comprises a gas-gas heat exchanger (1), a heater (2), a single-tube reactor (3), a cooling condenser (4), a gas-liquid separator I (5), an oil-water separator (6), a circulating compressor (7), a heat transfer oil circulating pump (8), a heat transfer oil cooler (9), a gas-liquid separator II (10), an expansion tank (11), a raw material hydrogen regulating valve (12), a raw material carbon dioxide regulating valve (13), a pressure reducing valve I (14), a regulating valve I (15), a pressure reducing valve II (16), a regulating valve II (17), a regulating valve III (20), a start-up heater (21), an iron-based tubular section (22), an iron-based insulation section (23), a molecular sieve insulation section (24), a tubular section shell (25), a tubular section reaction tube (26), and an electric heating belt (27); The outlet pipeline of the raw carbon dioxide regulating valve (13) is connected to the raw hydrogen pipeline of the outlet of the raw hydrogen regulating valve (12); the mixed raw carbon dioxide and raw hydrogen pipelines are connected to the cold side inlet pipeline of the gas-to-gas heat exchanger (1); the hot side outlet pipeline of the gas-to-gas heat exchanger (1) is connected to the cold side inlet of the heater (2); the hot side outlet pipeline of the heater (2) is connected to the top inlet of the single-tube reactor (3); the bottom outlet pipeline of the single-tube reactor (3) is connected to the hot side inlet of the gas-to-gas heat exchanger (1); the cold side outlet pipeline of the gas-to-gas heat exchanger (1) is connected to the hot side inlet of the cooling condenser (4); the cold side outlet pipeline of the cooling condenser (4) is connected to the inlet of the gas-liquid separator I (5); the bottom liquid phase outlet pipeline of the gas-liquid separator I (5) is regulated and controlled by the regulating valve I (15) and then connected to the inlet of the oil-water separator (6); The top gas phase outlet of the gas-liquid separator I (5) is divided into two paths, one of which is connected to the inlet of the circulation compressor (7), and the outlet pipeline of the circulation compressor (7) is connected to the pipeline of the raw material carbon dioxide and hydrogen mixed gas; the other is connected to the inlet pipeline of the pressure reducing valve I (14), and the gas pipeline at the outlet of the pressure reducing valve I (14) after decompression is connected to the tail gas main pipe; The top gas phase outlet pipeline of the oil-water separator (6) is connected to the inlet of the pressure reducing valve II (16); The bottom pipe opening of the expansion tank (11) is connected to the top pipe opening of the gas-liquid separator II (10) through a pipeline; the bottom outlet pipeline of the gas-liquid separator II (10) is connected to the inlet of the heat transfer oil circulation pump (8); the outlet of the heat transfer oil circulation pump (8) is divided into two paths, one of which is connected to the inlet of the regulating valve II (17), and the outlet pipeline of the regulating valve II (17) is connected to the cold side inlet of the start-up heater (21); the other path is connected to the hot side inlet pipeline of the heat transfer oil cooler (9), and the outlet pipeline of the heat transfer oil cooled by the heat transfer oil cooler (9) is connected to the outlet pipeline of the regulating valve II (17); the hot side outlet of the start-up heater (21) is connected to the heat transfer oil inlet below the tube section shell (25) of the single tube reactor (3); the heat transfer oil outlet pipeline above the tube section shell (25) of the single tube reactor (3) is connected to the inlet of the gas-liquid separator II (10); The raw hydrogen and raw carbon dioxide are heated in turn by heat exchange in a gas-to-gas heat exchanger (1), and further heated by a heater (2). The mixed heated gas is passed into a single tube reactor (3), and passes through a fixed bed catalyst bed of an iron-based tube section (22), an iron-based insulation section (23), and a molecular sieve insulation section (24) from top to bottom, where a chemical reaction occurs to obtain a reaction mixed gas. The start-up heater (21) in the heat transfer oil circulation system is turned off, and the heat transfer oil cooler (9) is turned on to control the temperature of the heat transfer oil circulation system, and further control the temperature of the iron-based catalyst bed in the reaction tube (26) of the tube section of the single tube reactor (3); the reaction mixture is cooled and condensed through the gas-to-gas heat exchanger (1) and the cooling condenser (4) from the bottom of the single tube reactor (3) to obtain a low-temperature mixed gas / liquid after cooling and partial condensation, and the low-temperature mixed gas / liquid is separated into gas and liquid through the gas-liquid separator I (5).

2. A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 1, It is characterized in that The single tube reactor (3) is composed of an iron-based tube section (22), an iron-based insulation section (23) and a molecular sieve insulation section (24) from top to bottom, and electric heating cables (27) are wound around the outer walls of the iron-based tube section (22), the iron-based insulation section (23) and the molecular sieve insulation section (24).

3. A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 1, It is characterized in that The heater (2) and the start-up heater (21) are electrically heated or steam heated.

4. A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 1, It is characterized in that It also includes a cryogenic refrigerator (18) and a gas-liquid separator III (19), wherein the top gas phase outlet pipeline of the gas-liquid separator I (5) is connected to the hot side inlet of the cryogenic refrigerator (18), the cold side outlet of the cryogenic refrigerator (18) is connected to the inlet of the gas-liquid separator III (19), and the bottom liquid phase outlet pipeline of the gas-liquid separator III (19) is connected to the inlet of the oil-water separator (6) after being regulated and controlled by a regulating valve III (20); the top gas phase outlet of the gas-liquid separator III (19) is divided into two paths, one of which is connected to the inlet of the circulating compressor (7), and the other is connected to the inlet pipeline of the pressure reducing valve I (14).

5. A single-tube test device for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 1, It is characterized in that It also includes a cryogenic refrigerator (18) and a gas-liquid separator III (19), wherein the circulating compressor (7) is arranged on the top gas phase outlet pipeline of the gas-liquid separator I (5), the outlet pipeline of the circulating compressor (7) is connected to the hot side inlet of the cryogenic refrigerator (18), the cold side outlet of the cryogenic refrigerator (18) is connected to the inlet of the gas-liquid separator III (19), and the bottom liquid phase outlet pipeline of the gas-liquid separator III (19) is connected to the inlet of the oil-water separator (6) after being regulated and controlled by a regulating valve III (20); the top gas phase outlet of the gas-liquid separator III (19) is divided into two paths, one of which is connected to the raw material carbon dioxide and hydrogen mixed gas pipeline, and the other is connected to the inlet pipeline of the pressure reducing valve I (14).

6. A single-tube test method for directly producing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide. It is characterized in that The following steps are involved: The heat transfer oil is sent to the expansion tank (11), and when the heat transfer oil circulation system is filled with the heat transfer oil and the heat transfer oil liquid level in the expansion tank (11) is at a suitable position, the heat transfer oil circulation pump (8) is turned on; Turn on the start-up heater (21) and the electric heating tape on the outer wall of the iron-based tube section (22), the iron-based insulation section (23) and the molecular sieve insulation section (24) of the single tube reactor (3) to heat the heat transfer oil circulation system and raise the temperature to the required set temperature; Fresh raw material carbon dioxide with a temperature of 10-50°C and a pressure of 1.5-7.0Mpa is introduced; fresh raw material hydrogen with a temperature of 10-50°C and a pressure of 1.5-7.0Mpa is introduced; The raw hydrogen and raw carbon dioxide are heated in turn by the gas-to-gas heat exchanger (1), and further heated by the heater (2). The temperature of the heated mixed heating gas is 250-450° C. During the heating process of the heating gas, the heat exchange load of the gas-to-gas heat exchanger (1) is gradually increased. The mixed heated gas is introduced into a single tube reactor (3), and passes through the fixed bed catalyst bed of the iron-based tube section (22), the iron-based insulation section (23) and the molecular sieve insulation section (24) from top to bottom, and a chemical reaction occurs to obtain a reaction mixed gas. The reaction temperature is 250-500° C., the pressure is 1.0-6.0 MPa, and the overall reaction equation is: nCO2+(n-6n)H2=n1CO+n2CH4+(n3C2-n5C4)+(n6C5-n12C11)+n13H2O, and the reaction catalyst is an iron-based / molecular sieve (Na-Fe3O4 / HZSM-5) multifunctional composite catalyst; The start-up heater (21) in the heat transfer oil circulation system is turned off, and the heat transfer oil cooler (9) is switched on to control the temperature of the heat transfer oil circulation system, and further control the temperature of the iron-based catalyst bed in the reaction tube (26) of the tube section of the single tube reactor (3); The reaction mixture is cooled and condensed by heat exchange in the gas-to-gas heat exchanger (1) and the cooling condenser (4) from the bottom of the single-tube reactor (3) to obtain a low-temperature mixed gas / liquid after cooling and partial condensation, wherein the temperature of the low-temperature mixed gas / liquid is -30 to 10°C; The low-temperature mixed gas / liquid is separated into gas and liquid by a gas-liquid separator I (5), and the pressure of the gas-liquid separator I (5) is 1.0-6.0 MPa; Part of the gas is directly recycled and combined with fresh raw gas after being pressurized by a circulating compressor (7). The circulating gas temperature is 0 to 60°C and the pressure is 1.5 to 7.0 MPa. The other part of the gas is decompressed by a pressure reducing valve I (14) and discharged as part of the tail gas.

7. A single-tube test method for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 6, It is characterized in that The liquid separated by the gas-liquid separator I (5) is regulated by a regulating valve I (15) to control its flow rate and enters the oil-water separator (6). The pressure of the oil-water separator is 0.5-3.0 MPa. The small amount of gas separated is decompressed by a pressure reducing valve II (16) and then discharged as tail gas. The separated liquid crude gasoline and waste water are continuously sent out.

8. A single-tube test method for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 6, It is characterized in that The gas separated by the gas-liquid separator I enters the cryogenic refrigerator (18) for further cooling and condensation. The outlet temperature of the cryogenic refrigerator (18) is -40 to 5°C. The low-temperature mixed gas / liquid at the outlet of the cryogenic refrigerator (18) is separated into gas and liquid by the gas-liquid separator III (19). The pressure of the gas-liquid separator III (19) is 1.0 to 6.0 MPa. A part of the gas is directly recycled and reused. After being pressurized by the circulating compressor (7), it is combined with the fresh raw gas. The circulating gas temperature is -20 to 50°C and the pressure is 1.5 to 7.0 MPa. The other part of the gas is depressurized by the pressure reducing valve I (14) and discharged as part of the tail gas.

9. A single-tube test method for directly preparing gasoline fraction hydrocarbons by hydrogenation of carbon dioxide according to claim 6, It is characterized in that The circulating compressor (7) is arranged on the pipeline between the top gas phase outlet of the gas-liquid separator I (5) and the hot side inlet of the cryogenic cooler (18).

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