A continuous method and system for producing triethylaluminum

Abstract

This invention relates to a low-energy-consumption, continuous, and intrinsically safe method and system for producing triethylaluminum. The system utilizes aluminum powder, hydrogen, and ethylene to produce triethylaluminum, comprising three parts: an aluminum powder preparation section, a hydrogenation reaction section, and an ethylation reaction section. This reaction system enables continuous hydrogenation of high-aluminum powder, continuous desolidification and separation of diethylaluminum hydride, and continuous ethylation of diethylaluminum hydride, achieving high conversion rates of aluminum powder and high selectivity for triethylaluminum. It is a low-energy-consumption, continuous production method with intrinsic safety characteristics.

Description

Technical Field

[0001] This invention belongs to the field of organometallic compound synthesis technology, specifically relating to a continuous production method and system for triethylaluminum. Using ethylene, aluminum powder and hydrogen as raw materials, a novel continuous process technology and catalyst are employed to achieve the continuous reaction of ethylene, aluminum powder and hydrogen to produce triethylaluminum. Background Technology

[0002] Triethylaluminum is an organometallic compound, a colorless and transparent liquid, mainly used as a catalyst, initiator, and rocket fuel. It can also be used for gas-coated aluminum.

[0003] Currently, triethylaluminum is generally produced using a two-step batch reactor process, consisting of hydrogenation and ethylation. After hydrogenation, the residual hydrogen pressure in the reactor is released, and then ethylene is introduced for ethylation. This process involves repeated heating and cooling of the equipment, resulting in significant energy waste. Furthermore, the reaction system contains large quantities of triethylaluminum and diethylaluminum hydride. The intermittent production operation and the large quantities of materials and products pose significant safety risks to the plant.

[0004] Chinese invention patent CN 115304631A discloses a method for improving the production efficiency of triethylaluminum by adding an activator. Titanium-aluminum powder and a sodium-potassium alloy activator are added to the triethylaluminum mother liquor, hydrogen gas is introduced to initiate a hydrogenation reaction, and then ethylation is carried out with ethylene to obtain crude triethylaluminum product. The invention reduces the initiation time of the hydrogenation reaction by adding the sodium-potassium alloy activator, increases the hydrogenation reaction rate to reduce the hydrogenation reaction time, and can also reduce the reaction temperature and pressure to a certain extent, avoiding an increase in side reactions. The crude triethylaluminum is purified by distillation, allowing some unreacted sodium-potassium alloy to be removed and treated during the distillation process, thus not affecting the quality of the final product and causing no additional environmental pollution during the production process.

[0005] Chinese utility model patent CN 201686638U discloses an apparatus for recovering triethylaluminum from residual liquid in the production of triethylaluminum. The recovery apparatus consists of a mixing device, a condensation reflux device, and a recovery tank connected sequentially by pipelines. The mixing device includes a stirred tank with an internal agitator, a jacketed exterior, and a residual liquid inlet, an oil inlet, and a steam outlet at the top. The condensation reflux device comprises a -35°C secondary cooler and a 10°C primary cooler connected together, with a vacuum device connected to the top.

[0006] Chinese utility model patent CN 201694831U discloses a hydrogen tail gas recovery system in the production of triethylaluminum. It includes a hydrogen flash tank, in which the hydrogen output end is sequentially connected via pipes to an oil-based cooler, a hydrogen recovery buffer tank, a hydrogen compressor, and a hydrogen storage tank. The top of the hydrogen storage tank has a hydrogen output port for hydrogen output and a hydrogen input port for external hydrogen input. The hydrogen generated during the triethylaluminum production process is recovered and treated by a 10°C primary cooler, a -35°C secondary cooler, and the hydrogen recovery buffer tank before entering the hydrogen storage tank under the action of the hydrogen compressor for reuse, thus saving hydrogen consumption.

[0007] Chinese utility model patent CN 201609595U discloses a solid impurity removal system before distillation in the production of triethylaluminum. This system utilizes a plate-type solid-film evaporator to fully recover solid impurities from triethylaluminum and transfer them to an impurity receiving tank. The triethylaluminum after passing through the plate-type solid-film evaporator then enters the distillation column for further distillation. This method facilitates stable distillation operation and allows for the recovery and reuse of solid impurities, thus saving production costs.

[0008] Chinese utility model patent CN 201694973U discloses an ethylene tail gas recovery system in the production of triethylaluminum, including an ethylene flash evaporator. The ethylene output end of the ethylene flash evaporator is connected in sequence to an oil-based cooler, an ethylene recovery buffer tank, an ethylene compressor, and an ethylene storage tank via pipelines. The ethylene produced during the triethylaluminum production process is recovered and treated by a 10°C primary cooler, a -35°C secondary cooler, and the ethylene recovery buffer tank. Triethylaluminum droplets are removed using a filtration screen in the ethylene recovery buffer tank, and then the ethylene enters the ethylene storage tank under the action of the ethylene compressor for reuse. This system recovers and utilizes a large amount of ethylene, saving production costs.

[0009] Chinese utility model patent CN 202315369U discloses a device for recovering residue from the reactor in the production of triethylaluminum. This invention improves product yield by adding cross-line pipes to recover triethylaluminum from the residue.

[0010] Chinese utility model patent CN 213840922U discloses a complete set of deactivation treatment equipment for residues in the production of triethylaluminum. The equipment includes a feed tank connected to a nitrogen inlet pipe, and a deactivator connected to the outlet of the feed tank. A blower is connected to the deactivator, and a cooler is connected to the outlet of the deactivator. A flue gas separator and a dust removal device are sequentially connected to the outlet of the cooler. This equipment rapidly and thoroughly deactivates the residues from the production of triethylaluminum without increasing environmental burden, thus promoting safe production.

[0011] In summary, given that current triethylaluminum production employs batch technology, and the hydrogenation reaction is mostly catalytically uncatalyzed with a long hydrogenation time, coupled with the challenge of separating aluminum shell solid waste from the product, resulting in high consumption of hydrogen, ethylene, and aluminum powder; furthermore, the large quantities of raw materials and products within the system pose safety hazards and lack inherent safety characteristics, it is essential to develop a low-energy-consumption, continuous production process with inherent safety features.

[0012] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned literature, such as discontinuous intermittent production, the difficulty of separating aluminum shell solid waste from products, and the high consumption of hydrogen, ethylene and aluminum powder. Summary of the Invention

[0013] This invention uses ethylene, aluminum powder, and hydrogen as raw materials to synthesize triethylaluminum. Specifically, it employs a novel continuous process technology and catalyst to achieve the continuous reaction of ethylene, aluminum powder, and hydrogen to produce triethylaluminum, reducing energy consumption, minimizing emissions of waste gas, wastewater, and solid waste, and increasing product yield. It is a low-energy, continuous, and inherently safe new process for producing triethylaluminum.

[0014] A continuous production method for triethylaluminum uses aluminum powder, hydrogen, and ethylene to produce triethylaluminum, comprising three reaction stages: aluminum powder preparation, hydrogenation reaction, and ethylation reaction. The hydrogenation reaction employs a gas-liquid-solid three-phase (hydrogenation) tubular reactor, and the reaction rate is increased by circulating hydrogen and adding a catalyst. The ethylation reaction employs a continuous (ethylation) gas-liquid two-phase tubular reactor.

[0015] In the continuous production method of triethylaluminum described above, a 18-crown ether-6 / aluminum trichloride complex is further used as a catalyst for the hydrogenation reaction of aluminum powder. This catalyst is a liquid catalyst, which is simple and convenient to transport and has stable chemical properties. Compared with the sodium-potassium alloy activators commonly used in the art (such as those disclosed in patent CN 115304631A), it is more in line with the characteristics of intrinsic safety.

[0016] Specifically, the continuous production method for triethylaluminum includes:

[0017] (1) Aluminum powder preparation: Triethylaluminum is used as a solvent and catalyst and mixed with aluminum powder. The aluminum powder is uniformly dispersed in the triethylaluminum solution to prepare an aluminum powder suspension.

[0018] (2) Hydrogenation reaction: Hydrogen gas and aluminum powder suspension are brought into countercurrent contact. Under the action of a catalyst, aluminum, hydrogen gas and triethylaluminum undergo a rapid hydrogenation reaction to obtain diethylaluminum hydride intermediate product.

[0019] Al+2Al(C2H5)3+1.5H2=3AlH(C2H5)2

[0020] (3) Ethylation reaction: After mixing the intermediate product diethylaluminum hydride with triethylaluminum, ethylene is added, and the diethylaluminum hydride undergoes an ethylation reaction to produce triethylaluminum product.

[0021] C2H4 + AlH(C2H5)2 = Al(C2H5)3

[0022] A continuous production system for triethylaluminum includes three reaction sections: an aluminum powder preparation section, a hydrogenation reaction section, and an ethylation reaction section. The aluminum powder preparation section includes a preparation vessel and a hydrogenation feed tank. The hydrogenation reaction section includes a hydrogenation reactor (i.e., a gas-liquid-solid three-phase tubular reactor), a hydrogenation heat exchanger, a hydrogenation circulation pump, a circulating hydrogen scrubbing tower, a circulating hydrogen compressor, a desoldering unit, a condenser, and a hydrogenation receiving tank. The ethylation reaction section includes an ethylation feed pump, a mixer, an ethylation reactor (i.e., a gas-liquid two-phase tubular reactor), an ethylation heat exchanger, and an ethylation circulation pump.

[0023] As described above, in a continuous triethylaluminum production system, the aluminum powder preparation section includes:

[0024] Triethylaluminum from the tank farm is used as a solvent and 18-crown ether-6 / aluminum trichloride complex is used as a catalyst. The mixture is then fed into the preparation vessel. Solid aluminum powder is sent from the aluminum powder storage tank to the top of the preparation vessel and then into the preparation vessel. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution to prepare a suspension. The suspension is then pumped into the hydrogenation feed tank. The two hydrogenation feed tanks are used interchangeably.

[0025] As described above, a continuous production system for triethylaluminum includes a hydrogenation reaction section comprising: switching after a hydrogenation feed tank is full, then pressurizing hydrogen to reach the feed pressure, and feeding the aluminum powder suspension into the upper part of the hydrogenation reactor (a gas-liquid-solid three-phase tubular reactor); fresh hydrogen enters the inlet of the circulating hydrogen compressor, and together with the circulating hydrogen, after compression and pressurization, enters the lower part of the reactor, where the reactor and the hydrogen and aluminum powder suspension come into countercurrent contact, and under the action of a catalyst, a rapid hydrogenation reaction occurs between aluminum, hydrogen, and triethylaluminum to obtain diethylaluminum hydride intermediate product; the reaction is carried out under excess hydrogen, and the excess hydrogen is discharged from the top of the reactor, washed by a circulating hydrogen scrubbing tower, and then desulfurized. The entrained diethylaluminum hydride is removed to obtain compressible hydrogen gas, which is then compressed in a compressor and recycled. The heat from the hydrogenation reaction is removed from the system through a circulating heat exchanger. The circulating liquid first enters the hydrogenation heat exchanger for cooling, and then a portion is sent to the top of the reactor by the hydrogenation circulation pump for circulating heat exchange, while the other portion is sent to the desoldering unit to separate the intermediate product diethylaluminum hydride from unreacted aluminum powder and non-reacting aluminum oxide (because aluminum metal reacts rapidly with oxygen in the air to form aluminum oxide, which coats the aluminum, and aluminum oxide does not undergo hydrogenation). This process is carried out under negative pressure. The diethylaluminum hydride gas at the top of the desoldering unit is condensed by a condenser and then enters the hydrogenation receiving tank.

[0026] Furthermore, the hydrogenation reaction section also includes a residue discharge system obtained from the bottom of the desoldering unit for environmentally friendly treatment.

[0027] As described above, a continuous triethylaluminum production system includes an ethylation reaction section comprising: an intermediate product, diethylaluminum hydride, is pumped from a hydrogenation receiving tank by an ethylation feed pump into a mixer, where it mixes with triethylaluminum from an ethylation circulation pump and enters the top of an ethylation reactor (a gas-liquid two-phase tubular reactor); ethylene enters the reactor from the lower part and reacts with diethylaluminum hydride to produce triethylaluminum; the heat of reaction is removed from the system through a circulating heat recovery system; the circulating liquid first enters an ethylation heat recovery unit for cooling, then enters the mixer under the pumping of the ethylation circulation pump to mix with diethylaluminum hydride, and finally enters the top of the reactor to achieve circulating heat recovery; the triethylaluminum product is obtained at the bottom of the reactor and discharged from the device.

[0028] The continuous production system for triethylaluminum, as described above, yields an aluminum powder conversion rate of ≥80% and a triethylaluminum selectivity of ≥98%.

[0029] This invention utilizes aluminum powder, hydrogen, and ethylene to produce triethylaluminum, and mainly consists of three parts: an aluminum powder preparation section, a hydrogenation section, and an ethylation section. See the specification for details. Figure 1 As shown.

[0030] The aluminum powder preparation section consists of one preparation vessel V-101 and two hydrogenation feed tanks V-102AB. Triethylaluminum from the tank area is mixed as a solvent and catalyst and then enters the preparation vessel. Aluminum powder simultaneously enters the preparation vessel from the top of the aluminum powder storage tank. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution to form a suspension, which is then sent to the hydrogenation feed tank V-102 by pump P-101. The two hydrogenation feed tanks are used interchangeably.

[0031] The hydrogenation section consists of a hydrogenation reactor R-101 (i.e., a gas-liquid-solid three-phase tubular reactor), a hydrogenation heat exchanger E-101, a hydrogenation circulation pump P-102, a circulating hydrogen scrubbing tower T-101, a circulating hydrogen compressor C-101, a desolvator E-102, a condenser E-103, and a hydrogenation receiving tank V-103. After one hydrogenation feed tank V-102 is full, the process switches to another. Hydrogen is then pressurized to reach the feed pressure, and the aluminum powder suspension is fed into the upper part of the hydrogenation reactor R-101. Fresh hydrogen enters the inlet of the circulating hydrogen compressor C-101 and, together with the circulating hydrogen, is compressed and pressurized before entering the lower part of the reactor. In the reactor, the hydrogen and aluminum powder suspension come into countercurrent contact, and under the action of a catalyst, a rapid hydrogenation reaction occurs between aluminum, hydrogen, and triethylaluminum to obtain diethylaluminum hydride as an intermediate product. The reaction proceeds through... The process is carried out under a certain amount of hydrogen. Excess hydrogen is discharged from the top of the reactor and, after being washed by the circulating hydrogen scrubbing tower T-101, the entrained diethylaluminum hydride is removed, yielding compressible hydrogen gas, which is then compressed by the compressor and recycled. The hydrogenation reaction is a strongly exothermic reaction, and the heat is removed from the system through a circulating heat recovery system. The circulating liquid first enters the hydrogenation heat recovery unit E-101 for cooling, and then, under the transport of the hydrogenation circulating pump P-102, part of it enters the top of the reactor for circulating heat recovery, while the other part is sent to the desoldering unit E-102. The desoldering unit separates the intermediate product diethylaluminum hydride from unreacted aluminum powder and alumina that does not participate in the reaction. It operates under negative pressure. The residue obtained at the bottom of the desoldering unit is discharged from the system for environmentally friendly treatment, while the diethylaluminum hydride gas at the top is condensed by the condenser E-103 and then enters the hydrogenation receiving tank V-103.

[0032] The ethylation section consists of an ethylation feed pump P-103, a mixer M-101, an ethylation reactor R-102 (i.e., a gas-liquid two-phase tubular reactor), an ethylation heat exchanger E-104, and an ethylation circulation pump P-104. The intermediate product, diethylaluminum hydride, is pumped from the hydrogenation receiving tank into the mixer by the ethylation feed pump. After mixing with triethylaluminum from the ethylation circulation pump P-104, it enters the top of the ethylation reactor. Ethylene enters the reactor from the lower part and undergoes an ethylation reaction with diethylaluminum hydride to produce triethylaluminum. This process is exothermic; the heat of reaction is removed from the system through a circulating heat exchanger. The circulating liquid first enters the ethylation heat exchanger E-104 for cooling, then enters the mixer under the flow of the ethylation circulation pump P-104 to mix with diethylaluminum hydride, and finally enters the top of the reactor, achieving circulating heat exchange. The triethylaluminum product is obtained at the bottom of the reactor and discharged from the system.

[0033] Beneficial effects

[0034] (1) This process system enables continuous production of triethylaluminum products with high purity;

[0035] (2) The continuous hydrogenation reaction and continuous ethylation reaction are adopted. The continuous reaction and equipment reduce the amount of hazardous chemicals remaining in the reaction system and have inherent safety characteristics; at the same time, the continuous separation of aluminum shell solid waste and products is realized.

[0036] (3) The hydrogenation reaction adopts a circulating hydrogen and tubular reactor design. The tubular reactor is a gas-liquid-solid three-phase tubular reactor. Hydrogen enters the lower part of the tubular reactor, and the raw material suspension enters from the top of the reactor. The gas and liquid phases flow countercurrently in the tubular reactor. The hydrogen exists in the form of small bubbles, which increases the contact surface between the two phases, strengthens the mass transfer and reaction interface between the two phases, and improves the hydrogenation reaction rate. During the reaction, the hydrogen is in excess. The unreacted hydrogen is discharged from the top of the reactor and circulates in the reactor after being compressed. The circulation of hydrogen increases the turbulence of the reactants, makes the gas-liquid contact more complete, strengthens the hydrogenation reaction, improves the reaction rate, and shortens the hydrogenation reaction time.

[0037] (4) The ethylation reaction adopts a tubular reactor design. The reactor adopts a gas-liquid two-phase tubular reactor. Ethylene gas enters the lower part of the tubular reactor, and the intermediate product diethylaluminum hydride enters from the upper part of the reactor. The gas and liquid phases flow countercurrently in the tubular reactor. Ethylene exists in the form of small bubbles under the distribution of the distributor, which increases the mass transfer and reaction interface between the two phases, improves the ethylation reaction rate, makes the ethylaluminum hydride ethylation reaction more complete, significantly reduces the occurrence of side reactions, and improves the selectivity of the target product triethylaluminum.

[0038] (5) The system utilizes a tubular reactor with external heat extraction technology, which improves the conversion rate of raw materials and the selectivity of the target product, triethylaluminum. External heat extraction is achieved by using external product circulation cooling technology. Without changing the total reaction residence time, it increases the internal circulation volume of liquid in the reactor, which significantly reduces the temperature change in the reaction section, reduces side reactions caused by local overheating, and improves the selectivity of the target product, triethylaluminum.

[0039] (6) By adding the catalyst 18-crown ether-6 / aluminum trichloride complex to the hydrogenation reaction, 18-crown ether-6 can increase the solubility of hydrogen and aluminum trichloride can destroy the aluminum oxide film, thereby accelerating the hydrogenation reaction rate of aluminum powder and greatly shortening the hydrogenation reaction time; at the same time, compared with the sodium-potassium alloy commonly used in the field disclosed in patent CN 115304631A, the catalyst of the present invention is liquid and has good stability, while the sodium-potassium alloy will spontaneously combust in air.

[0040] In summary, this reaction system can achieve high-speed continuous hydrogenation of aluminum powder, continuous desolidification and separation of diethylaluminum hydride, and continuous ethylation of diethylaluminum hydride, achieving high conversion rate of aluminum powder and high selectivity of triethylaluminum, with aluminum powder conversion rate ≥80% and triethylaluminum selectivity ≥98%.

[0041] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Attached Figure Description

[0042] Figure 1 This is a simplified process flow diagram for the production of triethylaluminum. Detailed Implementation

[0043] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0044] Figure 1 The system process flow for implementing the present invention is given.

[0045] Aluminum powder preparation section: Triethylaluminum solvent 1, for example, at around 40°C, from the tank area is mixed with catalyst 2 and then enters the preparation vessel. Aluminum powder flows from the aluminum powder storage tank into the preparation vessel by gravity from the top. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution and prepared into a suspension. The suspension is then sent by pump P-101 to hydrogenation feed tank V-102 as raw material for hydrogenation reaction.

[0046] Hydrogenation Reaction Section: The hydrogenation feed tank V-102A, filled to full level, is pressurized to 8–15 MPa using hydrogen gas 4. Under pressure, the aluminum powder suspension is fed into the upper part of the hydrogenation reactor R-101 (i.e., a gas-liquid-solid three-phase tubular reactor). The operating pressure at the top of the hydrogenation reactor is 8.5–14.5 MPa, and the operating temperature is 80–100℃. Fresh hydrogen gas 5 enters the inlet of the circulating hydrogen compressor C-101 and is compressed to 9–15 MPa together with the circulating purified hydrogen gas. It then enters the hydrogen distributor in the lower part of the reactor (i.e., the gas-liquid-solid three-phase tubular reactor). The hydrogen distributor distributes the hydrogen gas into small bubbles. These small hydrogen bubbles come into countercurrent contact with the aluminum powder suspension in the reactor. Under the catalytic action of the catalyst 18-crown ether-6 / aluminum trichloride complex, the raw material aluminum, hydrogen gas, and triethylaluminum undergo a hydrogenation reaction, converting the raw material into... Diethylaluminum hydride; the reaction is carried out under excess hydrogen, and the hydrogen-to-aluminum ratio (molar ratio) used in the reactor is 50-200; the circulating hydrogen is washed by the circulating hydrogen scrubbing tower T-101 at a temperature of 0-40℃ and a pressure of 8.5-14.5MPa. The wash oil is saturated hydrocarbon wash oil with aromatics and olefins removed. After washing, the hydrogen is freed from entrained diethylaluminum hydride and aluminum powder. The purified hydrogen and fresh hydrogen 5 are compressed together and recycled. The hydrogenation reaction is a strongly exothermic reaction. The temperature at the bottom of the reactor is controlled at 90-120℃. The heat of reaction is removed from the system through circulating heat recovery. The circulating liquid first enters the hydrogenation heat recovery unit E-101 to cool down to 80-100℃. Then, under the transportation of the hydrogenation circulating pump P-102, part of it enters the top of the reactor to achieve circulating heat recovery, and the other part is sent to the desolidifier E-102. The deconsolidator operates under negative pressure conditions, with a vacuum degree of -99 to -101 kPa and an operating temperature of 100 to 110°C. The intermediate product, diethylaluminum hydride, is distilled off as a gas from the top of the deconsolidator, while the residue 9 (mainly non-reacting aluminum oxide and a small amount of aluminum) is discharged from the bottom. The top gaseous diethylaluminum hydride is condensed to 35-45°C (e.g., 40°C) by condenser E-103 and enters the hydride receiving tank V-103, which is sealed with nitrogen 10 to isolate it from air. The negative pressure oil vacuum system 8 of the deconsolidator is implemented.

[0047] Ethylation Reaction Section: The intermediate product, diethylaluminum hydride, is pumped from the hydrogenation receiving tank V-103 by the ethylation feed pump P-103 into the mixer M-101. After mixing with triethylaluminum from the ethylation circulating pump P-104, it enters the top of the (ethylation) gas-liquid two-phase tubular reactor. The operating pressure at the top of the reactor is 0.05–0.2 MPa, and the operating temperature is 40–50 °C. Gaseous ethylene 12 enters the reactor from the lower part through an ethylene distributor. The distributor distributes the ethylene into small bubbles, which react with the diethylaluminum hydride to produce the triethylaluminum product. This process is a strongly exothermic reaction. The temperature at the bottom of the reactor is controlled at 60–75 °C. The heat of the reaction is removed from the system through a circulating heat recovery system. The circulating liquid first enters the ethylation heat recovery unit E-104 to cool to 30–50 °C, then, under the transport of the ethylation circulating pump P-104, it enters the mixer to mix with the diethylaluminum hydride, and finally enters the top of the reactor, achieving circulating heat recovery. The triethylaluminum product 13 obtained at the bottom of the reactor is pumped out of the ethylation circulation pump unit.

[0048] The following is a specific embodiment of the production process of triethylaluminum products according to the present invention, with a designed triethylaluminum production capacity of 700 kg / h.

[0049] (1) Aluminum powder preparation section: 2860 kg / h of triethylaluminum solvent 1 from the tank area at about 40°C is mixed with 3.0 kg / h of catalyst 2 and then enters the preparation vessel. 200 kg / h of aluminum powder flows into the preparation vessel from the top of the aluminum powder storage tank by gravity. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution and prepared into a suspension of 3063 kg / h. The suspension is sent to the hydrogenation feed tank V-102 by pump P-101 until it is full, and is used as the raw material for hydrogenation reaction feed.

[0050] (2) Hydrogenation Section: Hydrogen gas 4 is injected into the full-level hydrogenation feed tank V-102A to increase its pressure to 10.0 MPa. Under pressure, the flow rate of the aluminum powder suspension is controlled at 3063 kg / h, and it enters the upper part of the hydrogenation reactor R-101 (gas-liquid-solid three-phase tubular reactor). The operating pressure at the top of the hydrogenation reactor is 9.8 MPa, and the operating temperature is 90℃. Fresh hydrogen gas 5, at a pressure of 10.0 MPa, enters the inlet of the circulating hydrogen compressor C-101 at a rate of 7.5 kmol / h. The circulating purified hydrogen gas is 750 kmol / h. At this time, the hydrogen-aluminum ratio (molar ratio) is about 100. They are compressed together to 10.8 MPa and enter the hydrogen distributor in the lower part of the reactor. The hydrogen distributor distributes the hydrogen into small... In the reactor, small hydrogen bubbles come into countercurrent contact with the aluminum powder suspension. Catalyzed by the 18-crown ether-6 / aluminum trichloride complex, a hydrogenation reaction occurs between the raw material aluminum, hydrogen, and triethylaluminum, converting the raw material into diethylaluminum hydride. The circulating hydrogen is discharged from the top of the reactor and washed in a circulating hydrogen scrubbing tower T-101 at 30°C and 9.75 MPa. The wash oil is a saturated hydrocarbon wash oil with aromatics and olefins removed. After washing, the hydrogen is free of entrained diethylaluminum hydride and aluminum powder. The purified hydrogen, along with fresh hydrogen 5, is compressed and recycled. The hydrogen-to-aluminum ratio in the reactor is controlled by the compressor flow rate. The heat released from the hydrogenation reaction is extracted using a circulating heat recovery method. The circulating liquid first enters the hydrogenation heat recovery unit E-101 to cool to 80°C. Then, a portion is pumped by the hydrogenation circulation pump P-102 to the top of the reactor for circulating heat recovery, controlling the reactor top temperature at 90°C and the bottom temperature at 110°C, i.e., a reactor temperature rise of 20°C. A portion of the circulating liquid, with a flow rate of 3094 kg / h, is fed into the desoldering unit E-102. The desoldering unit operates under the following conditions: vacuum of -99 kPa and operating temperature of 106 °C. The intermediate product, diethylaluminum hydride, is vaporized from the top of the desolder at a flow rate of 3094 kg / h, while residue 9 is discharged from the bottom of the desolder at a flow rate of 145 kg / h. The vaporized diethylaluminum hydride at the top is condensed to 40 °C in the condenser E-103 and then enters the hydrogenation receiving tank V-103.

[0051] (3) Ethylation Section: Ethylation feed pump P-103 delivers diethylaluminum hydride at a flow rate of 3032 kg / h into mixer M-101, where it mixes with triethylaluminum hydride at 45°C from ethylation circulation pump P-104. The mixture then enters the top of the ethylation gas-liquid two-phase tubular reactor. The circulation rate is adjusted to control the operating pressure at the top of the reactor at 0.1 MPa and the operating temperature at 46°C. Gaseous ethylene 12 enters the reactor from the lower part through an ethylene distributor at a flow rate of 528 kg / h. The ethylene distributor distributes the ethylene into small bubbles, which react with the diethylaluminum hydride to produce triethylaluminum. This process is a strongly exothermic reaction. Heat is removed from the system through circulation, controlling the reactor temperature rise by 20°C, i.e., controlling the bottom temperature of the reactor at 66°C. The triethylaluminum product 13 obtained at the bottom of the reactor is pumped out of the device by the ethylation circulation pump at a flow rate of 700 kg / h.

[0052] The implementation results of this embodiment are: the energy consumption of the entire device for triethylaluminum product is 161.5 kg standard coal / t product, the aluminum powder conversion rate is ≥80%, and the triethylaluminum selectivity is ≥98%.

[0053] When using a traditional batch reaction process (e.g., a final reaction pressure of 9.8 MPa and an operating temperature of 90 °C), the energy consumption per unit of triethylaluminum product in the entire unit is 263.0 kg standard coal / t product, the aluminum powder conversion rate is ≤70%, and the triethylaluminum selectivity is ≤94%.

[0054] It is evident that the method of this invention reduces energy consumption by 101.5 kg standard coal / t of product compared to the traditional process, while significantly increasing conversion rate and selectivity. Therefore, this invention represents a novel process with low energy consumption and high continuous operation safety.

[0055] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A continuous production method for triethylaluminum, characterized in that, The production of triethylaluminum using aluminum powder, hydrogen, and ethylene includes three reaction stages: aluminum powder preparation, hydrogenation, and ethylation. The hydrogenation reaction uses a gas-liquid-solid three-phase tubular reactor, and the reaction rate is increased by circulating hydrogen and adding a catalyst. The ethylation reaction uses a continuous gas-liquid two-phase tubular reactor. The hydrogenation reaction uses an 18-crown ether-6 / aluminum trichloride complex as a catalyst.

2. A continuous production method for triethylaluminum according to claim 1, characterized in that, The production system used in the production method includes three sections: an aluminum powder preparation section, a hydrogenation reaction section, and an ethylation reaction section. The aluminum powder preparation section includes a preparation kettle and a hydrogenation feed tank. The hydrogenation reaction section includes a hydrogenation reactor, a hydrogenation heat exchanger, a hydrogenation circulating pump, a circulating hydrogen scrubbing tower, a circulating hydrogen compressor, a desoldering unit, a condenser, and a hydrogenation receiving tank. The ethylation reaction section includes an ethylation feed pump, a mixer, an ethylation reactor, an ethylation heat exchanger, and an ethylation circulating pump.

3. The continuous production method of triethylaluminum as described in claim 2, characterized in that, The aluminum powder preparation section includes: mixing triethylaluminum from the tank area as a solvent and 18-crown ether-6 / aluminum trichloride complex as a catalyst, and then feeding the mixture into the preparation vessel; solid aluminum powder is fed from the aluminum powder storage tank to the top of the preparation vessel and then into the preparation vessel; under the action of stirring, the aluminum powder is uniformly dispersed in the triethylaluminum solution to prepare a suspension, which is then pumped into the hydrogenation feed tank; the two hydrogenation feed tanks are used interchangeably.

4. The continuous production method of triethylaluminum as described in claim 3, characterized in that, The hydrogenation reaction section includes: switching after one hydrogenation feed tank is full, then using hydrogen pressurization to reach the feed pressure, and the aluminum powder suspension is fed into the upper part of the hydrogenation reactor; fresh hydrogen enters the inlet of the circulating hydrogen compressor, and together with the circulating hydrogen, after compression and pressurization, enters the lower part of the reactor, where the hydrogen and aluminum powder suspension come into countercurrent contact in the reactor, and under the action of a catalyst, aluminum, hydrogen, and triethylaluminum undergo a hydrogenation reaction to obtain diethylaluminum hydride intermediate product; the reaction is carried out under excess hydrogen, and the excess hydrogen is discharged from the top of the reactor and washed with circulating hydrogen. After washing, the entrained diethylaluminum hydride is removed, yielding compressible hydrogen gas, which is then compressed and recycled. The heat from the hydrogenation reaction is removed from the system through a circulating heat exchanger. The circulating liquid first enters the hydrogenation heat exchanger for cooling, and then, under the transport of the hydrogenation circulating pump, a portion enters the top of the reactor for circulating heat exchange, while the other portion is sent to the desoldering unit to separate the intermediate product diethylaluminum hydride from unreacted aluminum powder and non-reacting aluminum oxide. This unit operates under negative pressure. The diethylaluminum hydride gas at the top of the desoldering unit is condensed by a condenser and then enters the hydrogenation receiving tank.

5. The continuous production method of triethylaluminum as described in claim 4, characterized in that, The hydrogenation reaction section also includes a residue discharge system obtained from the bottom of the desoldering unit for environmentally friendly treatment.

6. The continuous production method of triethylaluminum as described in claim 2, characterized in that, The ethylation reaction section includes: the intermediate product diethylaluminum hydride is pumped from the hydrogenation receiving tank into the mixer by the ethylation feed pump, mixed with triethylaluminum from the ethylation circulation pump, and then enters the top of the ethylation reactor; ethylene enters the reactor from the lower part and undergoes an ethylation reaction with diethylaluminum hydride to produce triethylaluminum product; the heat of reaction is removed from the system through a circulating heat recovery system; the circulating liquid first enters the ethylation heat recovery unit for cooling, then enters the mixer under the conveying of the ethylation circulation pump to mix with diethylaluminum hydride, and finally enters the top of the reactor to achieve circulating heat recovery; the triethylaluminum product is obtained at the bottom of the reactor and is discharged from the device.

7. The continuous production method of triethylaluminum according to any one of claims 2-6, characterized in that, The production system includes: Aluminum powder preparation section: Triethylaluminum solvent (1) from the tank area is mixed with catalyst (2) and then enters the preparation vessel. Aluminum powder flows from the aluminum powder storage tank into the preparation vessel from the top. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution and prepared into a suspension. It is then pumped into the hydrogenation feed tank as the raw material for the hydrogenation reaction. Hydrogenation reaction section: The hydrogenation feed tank at full level is pressurized to 8~15 MPa using hydrogen (4). Under pressure, the aluminum powder suspension is fed into the upper part of the hydrogenation reactor. The operating pressure at the top of the hydrogenation reactor is 8.5~14.5 MPa, and the operating temperature is 80~100℃. Fresh hydrogen (5) enters the inlet of the circulating hydrogen compressor and is compressed to 9~15 MPa together with the circulating purified hydrogen. It enters the hydrogen distributor in the lower part of the reactor. The hydrogen distributor distributes the hydrogen into small bubbles. The small hydrogen bubbles come into countercurrent contact with the aluminum powder suspension in the reactor. Under the catalytic action of the catalyst 18-crown ether-6 / aluminum trichloride complex, the raw material aluminum, hydrogen and triethylaluminum undergo hydrogenation reaction, converting the raw material into diethylaluminum hydride. The reaction is carried out under excess hydrogen. The hydrogen-aluminum molar ratio used in the reactor is 50~200. The circulating hydrogen is washed by the circulating hydrogen scrubbing tower. The washing temperature is 0~40℃ and the pressure is 8.5~14℃. 0.5MPa, the wash oil is saturated hydrocarbon wash oil to remove aromatics and olefins. After washing, the hydrogen gas removes the entrained diethyl aluminum hydride and aluminum powder. The purified hydrogen gas and fresh hydrogen gas (5) are compressed together and then recycled. The bottom temperature of the reactor is controlled at 90~120℃. The heat of reaction is removed from the system through the circulating heat extraction. The circulating liquid first enters the hydrogenation heat extractor to cool down to 80~100℃. Then, a part of it is sent to the top of the reactor by the hydrogenation circulation pump to realize the circulating heat extraction. The other part is sent to the desoldering device. The desoldering device operates under negative pressure conditions, with a vacuum degree of -99~-101kPa and an operating temperature of 100~110℃. The intermediate product diethyl aluminum hydride is vaporized from the top of the desoldering device, and the residue (9) is discharged from the bottom of the desoldering device. The top gas diethyl aluminum hydride is condensed to 35-45℃ by the condenser and enters the hydrogenation receiving tank. The receiving tank is sealed with nitrogen (10) to isolate air. The negative pressure oil vacuum system (8) of the desoldering device is realized. Ethylation reaction section: The intermediate product diethylaluminum hydride is transported from the hydrogenation receiving tank to the mixer by the ethylation feed pump. After mixing with the triethylaluminum from the ethylation circulation pump, it enters the top of the ethylation reactor. The operating pressure at the top of the reactor is 0.05~0.2MPa, and the operating temperature is 40~50℃. Gaseous ethylene (12) enters the reactor from the lower part of the reactor through the ethylene distributor. The ethylene distributor distributes the ethylene into small bubbles. The small bubbles react with diethylaluminum hydride to produce triethylaluminum product. The temperature at the bottom of the reactor is controlled at 60~75℃. The heat of reaction is removed from the system through the circulating heat removal. The circulating liquid first enters the ethylation heat remover to cool down to 30~50℃, and then enters the mixer to mix with diethylaluminum hydride under the transport of the ethylation circulation pump. Finally, it enters the top of the reactor to achieve circulating heat removal. The triethylaluminum product (13) obtained at the bottom of the reactor is sent out of the device by the ethylation circulation pump.

8. The continuous production method of triethylaluminum as described in claim 2, characterized in that, Aluminum powder conversion rate ≥80%, triethylaluminum selectivity ≥98%.

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