Continuous production method and system for triethyl aluminum

Abstract

The invention relates to a low-energy-consumption continuous intrinsically safe triethyl aluminum production method and system, triethyl aluminum is produced by using aluminum powder, hydrogen and ethylene, and the system comprises three parts, namely an aluminum powder preparation section, a hydrogenation reaction section and an ethylation reaction section; the reaction system can realize continuous hydrogenation of the high aluminum powder, continuous solid removal and separation of the diethyl aluminum hydride and continuous ethylation of the diethyl aluminum hydride, realizes high conversion rate of the aluminum powder and high selectivity of the triethyl aluminum, and is a production method which is low in energy consumption, continuous and intrinsically safe.

Description

Technical Field

[0001] The invention belongs to the technical field of organic metal compound synthesis, and specifically relates to a continuous production method and system of triethylaluminum. The method uses ethylene, aluminum powder and hydrogen as raw materials, adopts a novel continuous process technology and a catalyst, and realizes the continuous reaction of ethylene, aluminum powder and hydrogen to produce triethylaluminum. Background Art

[0002] Triethylaluminum is an organic metal compound, a colorless transparent liquid, mainly used as a catalyst, initiator, rocket fuel, and can also be used for gas coating aluminum.

[0003] At present, the production of triethylaluminum generally adopts a two-step production process of intermittent reactors, which are hydrogenation reaction and ethylation reaction. After the hydrogenation reaction is completed, the residual pressure of hydrogen in the reactor will be vented, and then ethylene will be introduced for ethylation reaction. During the reaction process, there are repeated heating and cooling of the equipment, which wastes energy seriously. In addition, there are a large amount of triethylaluminum and diethylaluminum hydride stored in the reaction system. The intermittent production operation and the large amount of materials and products bring huge risks to the safety of the device.

[0004] Chinese invention patent CN 115304631A discloses a method for improving the production efficiency of triethylaluminum by adding an external activator. Titanium-containing aluminum powder and sodium-potassium alloy activator are added to the mother liquor of triethylaluminum, hydrogen is introduced for hydrogenation reaction, and then ethylation reaction is carried out with ethylene to obtain a crude triethylaluminum product. The invention reduces the initiation time of the hydrogenation reaction in the reaction by adding the sodium-potassium alloy activator, increases the hydrogenation reaction speed to reduce the hydrogenation reaction time, and can reduce the temperature and pressure of the reaction to a certain extent, avoiding the increase of side reactions. The crude triethylaluminum is purified by rectification, so that the insoluble matter generated by the unreacted sodium-potassium alloy and the reactants in the kettle can be removed and processed during the rectification process, thereby not affecting the quality of the final product, and the production process does not cause additional pollution to the environment.

[0005] Chinese utility model patent CN 201686638U discloses a device for recovering triethylaluminum from residual liquid produced by triethylaluminum production. The recovery device is composed of a mixing device, a condensation reflux device and a recovery tank connected in sequence through a set pipeline, wherein the mixing device includes a stirring kettle with a stirrer inside, a jacket is provided on the outside of the stirring kettle tank body, a residual liquid feed port, an oil inlet and a steam outlet are provided on the upper part of the stirring kettle, and the condensation reflux device is provided with a -35°C secondary cooler and a 10°C primary cooler connected together, and a vacuum device is connected on the top.

[0006] Chinese utility model patent CN 201694831U discloses a hydrogen tail gas recovery system in the production of triethyl aluminum. It includes a hydrogen flash tank, the hydrogen output end of the hydrogen flash tank is connected to an oil cooler, a hydrogen recovery buffer tank, a hydrogen compressor and a hydrogen storage tank in sequence through a set pipeline, and a hydrogen output port for hydrogen output and a hydrogen input port for external hydrogen input are set on the top of the hydrogen storage tank. The hydrogen generated in the production process of triethyl aluminum is recovered and processed by a 10℃ primary cooler, a -35℃ secondary cooler and a hydrogen recovery buffer tank, and then enters the hydrogen storage tank under the action of a hydrogen compressor for reuse, saving hydrogen consumption.

[0007] Chinese utility model patent CN 201609595U discloses a system for removing solid impurities before refinement in the production of triethyl aluminum. The system uses a plate-type solid film evaporator to fully recover solid impurities in triethyl aluminum to an impurity receiving tank, and the triethyl aluminum after the plate-type solid film evaporator enters a distillation tower for distillation. This method is conducive to the smooth operation of distillation, and solid impurities can be recycled and reused, saving production costs.

[0008] Chinese utility model patent CN 201694973U discloses an ethylene tail gas recovery system in triethyl aluminum production, including an ethylene flash evaporator, in which the ethylene output end of the ethylene flash evaporator is connected to an oil cooler, an ethylene recovery buffer tank, an ethylene compressor and an ethylene storage tank in sequence through a set pipeline. The ethylene produced in the triethyl aluminum production process is recovered and processed by a 10°C primary cooler, a -35°C secondary cooler and an ethylene recovery buffer tank, and then the triethyl aluminum droplets are removed by a liquid removal net in the ethylene recovery buffer tank, and then enter the ethylene storage tank under the action of the ethylene compressor for reuse, thereby recycling a large amount of ethylene and saving production costs.

[0009] Chinese utility model patent CN 202315369U discloses a device for recovering residual liquid in the production of triethyl aluminum. The invention recovers triethyl aluminum in residual liquid by adding a cross-line pipeline, thereby improving the product yield.

[0010] Chinese utility model patent CN 213840922U discloses a complete set of deactivation treatment equipment for residues in triethyl aluminum production, including a feed tank, the feed tank is connected to a nitrogen inlet pipe and the outlet end of the feed tank is connected to a deactivator, the deactivator is connected to a blower, and the outlet end of the deactivator is connected to a cooler, and the outlet end of the cooler is connected to a flue gas separation device and a dust removal device in sequence. The device quickly and thoroughly deactivates the residues produced by triethyl aluminum without increasing the environmental burden, which is conducive to safe production.

[0011] In summary, considering that the current production of triethylaluminum adopts intermittent production technology, and the hydrogenation reaction is mostly carried out without catalysis, the hydrogenation time is relatively long, and there is a problem of separating aluminum shell solid waste from products, resulting in high consumption of hydrogen, ethylene and aluminum powder; in addition, the system has a large amount of raw materials and products, which brings safety hazards to production and does not have intrinsic safety characteristics. It is very necessary to develop a continuous production process with low energy consumption, continuous operation and intrinsic safety characteristics.

[0012] The technical problem to be solved by the present invention is to overcome the defects existing in the above-mentioned documents, such as discontinuous intermittent production, separation problem of aluminum shell solid waste and product, and high consumption of hydrogen, ethylene and aluminum powder. Summary of the invention

[0013] The invention adopts ethylene, aluminum powder and hydrogen as raw materials to synthesize triethyl aluminum. Specifically, a new continuous process technology and catalyst are adopted to realize the continuous reaction of ethylene, aluminum powder and hydrogen to produce triethyl aluminum, reduce energy consumption, reduce the discharge of three wastes and improve the product yield. It is a new process for producing triethyl aluminum with low energy consumption, continuous and intrinsically safe characteristics.

[0014] A continuous production method of triethylaluminum uses aluminum powder, hydrogen and ethylene to produce triethylaluminum, including three reaction stages: aluminum powder preparation, hydrogenation reaction and ethylation reaction; the hydrogenation reaction adopts 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 adopts a continuous (ethylation) gas-liquid two-phase tubular reactor.

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

[0016] Specifically, the continuous production method of triethylaluminum comprises:

[0017] (1) Preparation of aluminum powder: triethylaluminum is used as a solvent and a catalyst, mixed with aluminum powder, and the aluminum powder is evenly dispersed in the triethylaluminum solution to prepare an aluminum powder suspension;

[0018] (2) Hydrogenation reaction: hydrogen gas and aluminum powder suspension are contacted in countercurrent, and under the action of a catalyst, a rapid hydrogenation reaction is achieved among aluminum, hydrogen gas and triethylaluminum to obtain a diethylaluminum hydride intermediate product;

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

[0020] (3) Ethylation reaction: After the intermediate product diethylaluminum hydride is mixed with triethylaluminum, ethylene is added to react with diethylaluminum hydride to produce triethylaluminum product.

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

[0022] A continuous production system of triethylaluminum comprises three reaction sections, namely, an aluminum powder preparation section, a hydrogenation reaction section and an ethylation reaction section; the aluminum powder preparation section comprises a preparation kettle and a hydrogenation feed tank; the hydrogenation reaction section comprises a hydrogenation reactor (i.e., a gas-liquid-solid three-phase tubular reactor), a hydrogenation heat collector, a hydrogenation circulation pump, a circulating hydrogen washing tower, a circulating hydrogen compressor, a desolidifier, a condenser and a hydrogenation receiving tank; and the ethylation reaction section comprises an ethylation feed pump, a mixer, an ethylation reactor (i.e., a gas-liquid two-phase tubular reactor), an ethylation heat collector and an ethylation circulation pump.

[0023] A triethylaluminum continuous production system as described above, wherein the aluminum powder preparation section comprises:

[0024] The triethylaluminum from the tank area is used as a solvent and the 18-crown ether-6 / aluminum trichloride complex is used as a catalyst. The mixture is then fed into the preparation kettle. The solid powdered aluminum powder is fed from the aluminum powder storage tank to the top of the preparation kettle, and then enters the preparation kettle. Under the action of stirring, the aluminum powder is evenly 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.

[0025] The above-mentioned continuous production system of triethylaluminum, wherein the hydrogenation reaction section comprises: after a hydrogenation feed tank is full of liquid, it is switched, and then hydrogen is used to increase the pressure to reach the feed pressure, and the aluminum powder suspension is sent to the upper part of the hydrogenation reactor (gas-liquid-solid three-phase tubular reactor); fresh hydrogen enters the inlet of the circulating hydrogen compressor, and after compression and pressure increase together with the circulating hydrogen, enters the lower part of the reactor, and in the reactor, the hydrogen and the aluminum powder suspension are in countercurrent contact, and under the action of the catalyst, a rapid hydrogenation reaction of aluminum, hydrogen and triethylaluminum is achieved to obtain a 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 after washing in the circulating hydrogen washing tower, the degassing is carried out. The entrained diethylaluminum hydride is removed to obtain compressible hydrogen, which enters the compressor for compression and then circulation; the heat of the hydrogenation reaction is removed from the system through circulating heat extraction, and the circulating liquid first enters the hydrogenation heat collector for cooling, and then a part of it is transported by the hydrogenation circulation pump to the top of the reactor to achieve circulating heat extraction, and the other part is sent to the desoldering device to separate the intermediate product diethylaluminum hydride and the unreacted aluminum powder and the aluminum oxide that does not participate in the reaction (because the aluminum metal will quickly react with the oxygen in the air to generate aluminum oxide, and the aluminum oxide will not undergo hydrogenation reaction). It works under negative pressure; the diethylaluminum hydride gas at the top of the desoldering device is condensed by the condenser and enters the hydrogenation receiving tank.

[0026] Furthermore, the hydrogenation reaction section also includes: a residue discharge system obtained at the bottom of the desolidifier for environmentally friendly treatment.

[0027] A continuous production system of triethylaluminum as described above, wherein the ethylation reaction section comprises: the intermediate product diethylaluminum hydride is transported from the hydrogenation receiving tank by the ethylation feed pump into the mixer, mixed with the triethylaluminum from the ethylation circulation pump and then enters the top of the ethylation reactor (gas-liquid two-phase tubular reactor), ethylene enters the reactor from the lower middle part of the reactor, and reacts with diethylaluminum hydride to produce triethylaluminum product; the reaction heat is removed from the system through circulating heat extraction, the circulating liquid first enters the ethylation heat extractor for cooling, then enters the mixer for mixing with diethylaluminum hydride under the transportation of the ethylation circulation pump, and finally enters the top of the reactor to realize circulating heat extraction; the triethylaluminum product is obtained at the bottom of the reactor and sent out of the device.

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

[0029] The present invention utilizes aluminum powder, hydrogen and ethylene to produce triethylaluminum, which is mainly divided into three parts: aluminum powder preparation section, hydrogenation section and ethylation section. Figure 1 shown.

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

[0031] The hydrogenation section is composed of a hydrogenation reactor R-101 (i.e., a gas-liquid-solid three-phase tubular reactor), a hydrogenation heat collector E-101, a hydrogenation circulation pump P-102, a circulating hydrogen washing tower T-101, a circulating hydrogen compressor C-101, a desoldering device E-102, a condenser E-103, and a hydrogenation receiving tank V-103. After a hydrogenation feed tank V-102 is full of liquid, it is switched, and then hydrogen is used to increase the pressure 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 after compression and pressure increase together with the circulating hydrogen, it enters the middle and lower part of the reactor, and in the reactor, the hydrogen and aluminum powder suspension are in countercurrent contact, and under the action of the catalyst, a rapid hydrogenation reaction of aluminum, hydrogen and triethylaluminum is achieved to obtain a diethylaluminum hydride intermediate product; the reaction is carried out in a process The reaction is carried out under a certain amount of hydrogen. Excess hydrogen is discharged from the top of the reactor. After washing in the circulating hydrogen washing tower T-101, the entrained diethylaluminum hydride is removed to obtain compressible hydrogen, which enters the compressor for compression and recycling. The hydrogenation reaction is a highly exothermic reaction. The heat is removed from the system through circulating heat extraction. The circulating liquid first enters the hydrogenation heat extractor E-101 for cooling, and then a part of it is transported by the hydrogenation circulating pump P-102 to the top of the reactor to achieve circulating heat extraction, and the other part is sent to the desolder E-102. The desolder is used to separate the intermediate product diethylaluminum hydride from the unreacted aluminum powder and the aluminum oxide that does not participate in the reaction. It works under negative pressure. The residue obtained at the bottom of the desolder is discharged from the system for environmental protection treatment. The diethylaluminum hydride gas at the top is condensed by the condenser E-103 and enters the hydrogenation receiving tank V-103.

[0032] The ethylation section is composed 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 extractor E-104, and an ethylation circulation pump P-104. The intermediate product diethylaluminum hydride is transported from the hydrogenation receiving tank into the mixer by the ethylation feed pump, mixed with triethylaluminum from the ethylation circulation pump P-104, and then enters the top of the ethylation reactor. Ethylene enters the reactor from the lower middle part of the reactor and reacts with diethylaluminum hydride to produce triethylaluminum products. This process is an exothermic reaction, and the reaction heat is removed from the system by circulating heat extraction. The circulating liquid first enters the ethylation heat extractor E-104 to cool down, then enters the mixer to mix with diethylaluminum hydride under the transportation of the ethylation circulation pump P-104, and finally enters the top of the reactor to achieve circulating heat extraction. The triethylaluminum product is obtained at the bottom of the reactor and sent out of the device.

[0033] Beneficial Effects

[0034] (1) This process system realizes continuous production of triethyl aluminum products with high product purity;

[0035] (2) The continuous hydrogenation reaction and the continuous ethylation reaction are adopted. The continuous reaction and the device reduce the retention volume of hazardous chemicals in the reaction system and have the characteristics of intrinsic safety. 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 adopts a gas-liquid-solid three-phase tubular reactor. Hydrogen enters the lower middle part of the tubular reactor, and the raw material suspension enters from the upper part of the reactor. The gas and liquid phases flow countercurrently in the tubular reactor. Hydrogen exists in the form of small bubbles, which increases the contact surface of the two phases, strengthens the mass transfer and reaction phase interface between the two phases, and improves the hydrogenation reaction rate. In the reaction process, hydrogen is excessive, and the unreacted hydrogen is discharged from the top of the reactor. After circulating compression, it realizes a circulating flow in the reactor. The circulation of hydrogen increases the turbulence of the reaction materials, 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 middle 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 phase interface between the two phases, improves the ethylation reaction rate, makes the diethylaluminum hydride ethylation reaction more complete, and significantly reduces the occurrence of side reactions, thereby improving the selectivity of the target product triethylaluminum.

[0038] (5) The system uses tubular reactor + external heat extraction technology to improve the conversion rate of raw materials and the selectivity of the target product triethylaluminum. The external heat extraction is achieved by the technical means of product external circulation cooling. Under the condition of not changing the total reaction residence time, the internal circulation amount of liquid in the reactor is increased, so that the temperature change in the reaction section is significantly reduced, the side reactions caused by local overheating are reduced, and the selectivity of the target product triethylaluminum is improved.

[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 aluminum powder hydrogenation reaction rate and greatly shortening the hydrogenation reaction time; at the same time, compared with the sodium potassium alloy commonly used in the art disclosed in, for example, patent CN 115304631A, the catalyst of the present invention is liquid and has good stability, while the sodium potassium alloy will spontaneously combust in the air.

[0040] In summary, the reaction system can realize 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, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a simplified process flow chart for the production of triethylaluminum. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for 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 at about 40°C from the tank area is mixed with catalyst 2 and then enters the preparation kettle. Aluminum powder flows from the aluminum powder storage tank into the preparation kettle from the top of the preparation kettle. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution to form a suspension, which is sent to the hydrogenation feed tank V-102 by pump P-101 as the raw material for hydrogenation reaction feed.

[0046] Hydrogenation reaction section: the full liquid level hydrogenation feed tank V-102A is pressurized to 8-15MPa using hydrogen 4. Under the action of 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 8.5-14.5MPa, and the operating temperature is 80-100°C. Fresh hydrogen 5 enters the inlet of the circulating hydrogen compressor C-101, and is compressed to 9-15MPa together with the circulating purified hydrogen, and enters the hydrogen distributor in the lower part of the reactor (i.e., a gas-liquid-solid three-phase tubular reactor). The hydrogen distributor distributes the hydrogen into small bubbles, which are countercurrently contacted with the aluminum powder suspension in the reactor. Under the catalytic action of the catalyst 18-crown ether-6 / aluminum trichloride complex, the raw aluminum, hydrogen and triethylaluminum undergo a hydrogenation reaction to convert 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 a circulating hydrogen washing tower T-101, the washing temperature is 0-40°C, the pressure is 8.5-14.5MPa, the washing oil is a saturated hydrocarbon washing oil for removing aromatics and olefins, and the hydrogen after washing removes the entrained diethylaluminum hydride and aluminum powder, and the purified hydrogen and fresh hydrogen 5 enter the compressor together for compression and recycling; the hydrogenation reaction is a strong exothermic reaction, and the temperature at the bottom of the reactor is controlled at 90-120°C. The reaction heat is removed from the system by circulating heat extraction, and the circulating liquid first enters the hydrogenation heat extractor E-101 to cool down to 80-100°C, and then a part is transported by the hydrogenation circulating pump P-102 to the top of the reactor to achieve circulating heat extraction, and the other part is sent to the desoldering device E-102. The desolder is operated 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 evaporated from the upper part of the desolder as gas, and the residue 9 (mainly aluminum oxide and a small amount of aluminum that do not participate in the reaction) is discharged from the bottom of the desolder; the top gas diethylaluminum hydride is condensed to 35-45°C (for example, 40°C) by the condenser E-103 and enters the hydrogenation receiving tank V-103, which is sealed with nitrogen 10 to isolate the air. The desolder is realized by the negative pressure oil vacuum system 8.

[0047] Ethylation reaction section: the intermediate product diethylaluminum hydride is transported from the hydrogenation receiving tank V-103 by the ethylation feed pump P-103 into the mixer M-101, mixed with the triethylaluminum from the ethylation circulation pump P-104 and then enters the top of the (ethylation) gas-liquid two-phase tubular reactor. The operating pressure at the top of the reactor is 0.05-0.2MPa, and the operating temperature is 40-50°C; gaseous ethylene 12 enters the reactor from the lower middle part of the reactor through the ethylene distributor, and the ethylene distributor distributes ethylene into small bubbles, which react with diethylaluminum hydride to obtain triethylaluminum product. This process is a strong exothermic reaction, and the temperature at the bottom of the reactor is controlled at 60-75°C. The reaction heat is removed from the system by circulating heat extraction. The circulating liquid first enters the ethylation heat extractor E-104 to cool down to 30-50°C, and then enters the mixer to mix with diethylaluminum hydride under the transportation of the ethylation circulation pump P-104, and finally enters the top of the reactor to achieve circulating heat extraction. The triethylaluminum product 13 obtained at the bottom of the reactor is pumped out of the device by the ethylation circulation pump.

[0048] The following is a specific triethyl aluminum product production process operation flow example of the present invention, designed triethyl aluminum 700kg / h.

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

[0050] (2) Hydrogenation stage: Hydrogen 4 is injected into the hydrogenation feed tank V-102A which is full of liquid level, and its pressure is raised to 10.0 MPa. Under the action of pressure, the aluminum powder suspension flow rate is controlled to 3063 kg / h and 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°C; fresh hydrogen 5 at a pressure of 10.0 MPa enters the inlet of the circulating hydrogen compressor C-101 at 7.5 kmol / h, and the circulating purified hydrogen is 750 kmol / h. At this time, the hydrogen-to-aluminum ratio (molar ratio) is about 100, and they are compressed to 10.8 MPa together and enter the hydrogen distributor in the lower part of the reactor. The hydrogen distributor distributes the hydrogen into small Bubbles, small hydrogen bubbles are countercurrently contacted in the reactor and the aluminum powder suspension, and under the catalytic action of the catalyst 18-crown ether-6 / aluminum trichloride complex, the raw aluminum, hydrogen and triethylaluminum are hydrogenated to convert the raw material into diethylaluminum hydride; the circulating hydrogen is discharged from the top of the reactor and washed by the circulating hydrogen washing tower T-101. The washing temperature is 30°C and the pressure is 9.75MPa. The washing oil is a saturated hydrocarbon washing oil that removes aromatics and olefins. The hydrogen after washing removes the entrained diethylaluminum hydride and aluminum powder. The purified hydrogen and fresh hydrogen 5 enter the compressor together for compression and recycling. The hydrogen-aluminum ratio in the reactor is controlled by the compressor flow rate; the heat released by the hydrogenation reaction is taken out by circulating heat extraction. The circulating liquid first enters the hydrogenation heat collector E-101 to cool down to 80°C, and then the next part is transported by the hydrogenation circulating pump P-102 to the top of the reactor to achieve circulating heat extraction, and the top temperature of the reactor is controlled to be 90°C and the bottom temperature is controlled to be 110°C, that is, the reactor temperature rises by 20°C. A part of the circulating liquid with a flow rate of 3094 kg / h is sent to the desolderer E-102. The operating conditions of the desolderer are vacuum degree at -99 kPa and operating temperature at 106°C. The intermediate product diethylaluminum hydride is evaporated from the upper part of the desolderer in the form of gas with a flow rate of 3094 kg / h. The residue 9 is discharged from the bottom of the desolderer with a flow rate of 145 kg / h. The top gas diethylaluminum hydride is condensed to 40°C through the condenser E-103 and enters the hydrogenation receiving tank V-103.

[0051] (3) Ethylation section: The ethylation feed pump P-103 delivers diethylaluminum hydride at a flow rate of 3032kg / h into the mixer M-101, and after mixing with triethylaluminum at 45°C from the ethylation circulation pump P-104, it enters the top of the ethylation gas-liquid two-phase tubular reactor. The circulation volume is adjusted to control the operating pressure at the top of the reactor to 0.1MPa and the operating temperature to 46°C; gaseous ethylene 12 enters the reactor from the lower middle part of the reactor through the ethylene distributor at a flow rate of 528kg / h. The ethylene distributor distributes ethylene into small bubbles, and the small bubble ethylene reacts with diethylaluminum hydride to obtain triethylaluminum product. This process is a highly exothermic reaction. By circulating heat removal system, the reactor temperature rise is controlled by 20°C, that is, the temperature at the bottom of the reactor is controlled at 66°C. The triethylaluminum product 13 obtained at the bottom of the reactor is sent out of the device by the ethylation circulation pump at a flow rate of 700kg / h.

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

[0053] When the traditional intermittent reaction process is adopted (for example, the final reaction pressure is 9.8 MPa and the operating temperature is 90°C), the energy consumption of the triethyl aluminum product of the entire device is 263.0 kg standard coal / t product, the aluminum powder conversion rate is ≤70%, and the triethyl aluminum selectivity is ≤94%.

[0054] It can be seen that the method of the present invention reduces the unit consumption by 101.5 kg standard coal / t product compared with the traditional process, and the conversion rate and selectivity are significantly improved. It can be seen that the present invention is a new process with low energy consumption and high continuous safety.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A continuous production method of triethylaluminum, characterized in that: The production of triethylaluminum using aluminum powder, hydrogen and ethylene includes three reaction stages: aluminum powder preparation, hydrogenation reaction and ethylation reaction. The hydrogenation reaction adopts a gas-liquid-solid three-phase tubular reactor, and the reaction rate is increased by circulating hydrogen and adding a catalyst. The ethylation reaction adopts a continuous gas-liquid two-phase tubular reactor.

2. A method for continuous production of triethylaluminum as claimed in claim 1, further characterized in that the hydrogenation reaction adopts 18-crown ether-6 / aluminum chloride complex as catalyst.

3. A continuous production system of triethyl aluminum, characterized in that: It includes three sections: aluminum powder preparation section, hydrogenation reaction section and 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 collector, a hydrogenation circulation pump, a circulating hydrogen washing tower, a circulating hydrogen compressor, a desolidifier, a condenser and a hydrogenation receiving tank; the ethylation reaction section includes an ethylation feed pump, a mixer, an ethylation reactor, an ethylation heat collector and an ethylation circulation pump.

4. A continuous production system of triethylaluminum as claimed in claim 1 or claim 3, further characterized in that the aluminum powder preparation section comprises: The triethylaluminum from the tank area is used as a solvent and the 18-crown ether-6 / aluminum trichloride complex is used as a catalyst. The mixture is then fed into the preparation kettle. The solid powdered aluminum powder is fed from the aluminum powder storage tank to the top of the preparation kettle, and then enters the preparation kettle. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution to form a suspension, which is then fed into the hydrogenation feed tank by a pump. The two hydrogenation feed tanks are used interchangeably.

5. A continuous production system of triethylaluminum as claimed in claim 3, further characterized in that: The hydrogenation reaction section comprises: after one hydrogenation feed tank is full of liquid, switching is performed, and then hydrogen is used to increase the pressure 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 after compression and pressure increase together with the circulating hydrogen, enters the middle and lower part of the reactor, and the hydrogen and the aluminum powder suspension are in countercurrent contact in the reactor, and under the action of the catalyst, a rapid hydrogenation reaction of aluminum, hydrogen and triethylaluminum is achieved to obtain a 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 after the circulating hydrogen After washing in the washing tower, the entrained diethylaluminum hydride is removed to obtain compressible hydrogen, which enters the compressor for compression and then circulation. The heat of the hydrogenation reaction is removed from the system through circulating heat extraction. The circulating liquid first enters the hydrogenation heat collector for cooling, and then a part of it is transported by the hydrogenation circulating pump to the top of the reactor to achieve circulating heat extraction, and the other part is sent to the desoldering device to separate the intermediate product diethylaluminum hydride and the unreacted aluminum powder and the aluminum oxide that does not participate in the reaction. It works under negative pressure. The diethylaluminum hydride vapor at the top of the desoldering device is condensed by the condenser and enters the hydrogenation receiving tank.

6. A continuous production system of triethylaluminum as claimed in claim 5, further characterized in that the hydrogenation reaction section further comprises: The residue obtained at the bottom of the desolder is discharged into the system for environmentally friendly treatment.

7. A continuous production system of triethylaluminum as claimed in claim 3, further characterized in that the ethylation reaction section comprises: The intermediate product diethylaluminum hydride is transported 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 middle part of the reactor and reacts with diethylaluminum hydride to produce triethylaluminum product. The reaction heat is removed from the system through circulating heat extraction. The circulating liquid first enters the ethylation heat extractor for cooling, then enters the mixer for mixing with diethylaluminum hydride under the transportation of the ethylation circulation pump, and finally enters the top of the reactor to realize circulating heat extraction. The triethylaluminum product is obtained at the bottom of the reactor and sent out of the device.

8. A continuous production system of triethylaluminum as claimed in any one of claims 3 to 7, further characterized in that: The system comprises: Aluminum powder preparation section: triethylaluminum solvent (1) from the tank area is mixed with catalyst (2) and then enters the preparation kettle. Aluminum powder flows from the aluminum powder storage tank to the preparation kettle from the top of the preparation kettle. Under the action of stirring, the aluminum powder is evenly dispersed in the triethylaluminum solution to prepare a suspension, which is pumped into the hydrogenation feed tank as a raw material for hydrogenation reaction feed; The hydrogenation reaction section: the hydrogenation feed tank filled with liquid level is increased in pressure to 8-15 MPa by using hydrogen (4), and the aluminum powder suspension is fed into the upper part of the hydrogenation reactor under the action of the pressure; the operating pressure at the top of the hydrogenation reactor is 8.5-14.5 MPa, and the operating temperature is 80-100° C. The fresh hydrogen (5) enters the inlet of the circulating hydrogen compressor, and is compressed to 9-15 MPa together with the circulating purified hydrogen, and enters the hydrogen distributor in the lower part of the reactor. The hydrogen distributor distributes the hydrogen into small bubbles, and the small hydrogen bubbles are in 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 aluminum, hydrogen and triethylaluminum are hydrogenated to convert the raw material into diethylaluminum hydride; the reaction is carried out under excess hydrogen, and the hydrogen-aluminum molar ratio used in the reactor is 50-200; the circulating hydrogen is washed by a circulating hydrogen washing tower, and the washing temperature is 0-40° C. and the pressure is 8.5-14 .5MPa, the washing oil is a saturated hydrocarbon washing oil from which aromatics and olefins are removed, and the hydrogen after washing removes the entrained diethylaluminum hydride and aluminum powder, and the purified hydrogen and fresh hydrogen (5) enter the compressor for compression and recycling; the bottom temperature of the reactor is controlled at 90-120°C, and the reaction heat is removed from the system by circulating heat extraction, and the circulating liquid first enters the hydrogenation heat collector to cool to 80-100°C, and then a part of it is transported by the hydrogenation circulation pump to the top of the reactor to achieve circulating heat extraction, and the other part is sent to the desolder; the desolder is operated under negative pressure conditions, the vacuum degree is between -99 and -101 kPa, and the operating temperature is 100-110°C. The intermediate product diethylaluminum hydride evaporates from the top of the desolder as gas, and the residue (9) is discharged from the bottom of the desolder; the top gas diethylaluminum hydride is condensed to 35-45°C by the condenser and enters the hydrogenation receiving tank, and the receiving tank is sealed and isolated from the air with nitrogen (10); the negative pressure oil vacuum system (8) of the desolder is realized; Ethylation reaction section: the intermediate product diethylaluminum hydride is transported from the hydrogenation receiving tank by the ethylation feed pump into the mixer, mixed with the triethylaluminum from the ethylation circulation pump and then 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°C; gaseous ethylene (12) enters the reactor from the lower middle part of the reactor through the ethylene distributor, and the ethylene distributor distributes the ethylene into small bubbles, which react with diethylaluminum hydride to obtain the triethylaluminum product; the temperature at the bottom of the reactor is controlled at 60-75°C, and the reaction heat is removed from the system by circulating heat extraction. The circulating liquid first enters the ethylation heat extractor to cool to 30-50°C, and then enters the mixer under the transportation of the ethylation circulation pump to mix with diethylaluminum hydride, and finally enters the top of the reactor to realize circulating heat extraction; the triethylaluminum product (13) obtained at the bottom of the reactor is sent out of the device by the ethylation circulation pump.

9. The continuous production system of triethyl aluminum according to any one of claims 3 to 8, characterized in that: The aluminum powder conversion rate is ≥80%, and the triethyl aluminum selectivity is ≥98%.

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