阅读说明：本技术 一种气相催化水合法制备乙二醇的强化反应系统及方法 (Enhanced reaction system and method for preparing ethylene glycol by gas-phase catalytic hydration method ) 是由 张志炳 周政 李磊 张锋 孟为民 王宝荣 杨高东 罗华勋 田洪舟 杨国强 曹宇 于 2020-11-30 设计创作，主要内容包括：本发明提供了一种气相催化水合法制备乙二醇的强化反应系统,包括：水合反应精馏器、强化水合反应精馏器和蒸发塔；所述水合反应精馏器的侧壁上设置有环氧乙烷进口；所述水合反应精馏器底部设置有进水口；所述水合反应精馏器内部设置有气动式微界面发生器和第一液动式微界面发生器,所述气动式微界面发生器设置在所述第一液动式微界面发生器的下方。本发明的强化反应系统设备组件少、占地面积小、能耗低、成本低、安全性高、反应可控,原料转化率高,相当于为乙二醇制备领域提供了一种操作性更强的反应系统,值得广泛推广应用。(The invention provides a reinforced reaction system for preparing ethylene glycol by a gas-phase catalytic hydration method, which comprises the following steps: a hydration reaction rectifier, an enhanced hydration reaction rectifier and an evaporation tower; an ethylene oxide inlet is formed in the side wall of the hydration reaction rectifier; the bottom of the hydration reaction rectifier is provided with a water inlet; the hydration reaction rectifier is internally provided with a pneumatic micro-interface generator and a first hydraulic micro-interface generator, and the pneumatic micro-interface generator is arranged below the first hydraulic micro-interface generator. The intensified reaction system disclosed by the invention has the advantages of few equipment components, small occupied area, low energy consumption, low cost, high safety, controllable reaction and high raw material conversion rate, is equivalent to providing a reaction system with stronger operability for the field of ethylene glycol preparation, and is worthy of wide popularization and application.)

1. An enhanced reaction system for preparing ethylene glycol by a gas-phase catalytic hydration method is characterized by comprising the following steps: a hydration reaction rectifier, an enhanced hydration reaction rectifier and an evaporation tower; an ethylene oxide inlet is formed in the side wall of the hydration reaction rectifier; the bottom of the hydration reaction rectifier is provided with a water inlet;

a pneumatic micro-interface generator and a first hydraulic micro-interface generator are arranged in the hydration reaction rectifier, and the pneumatic micro-interface generator is arranged below the first hydraulic micro-interface generator; the pneumatic micro-interface generator and the first hydraulic micro-interface generator are both connected with the ethylene oxide inlet and are used for crushing ethylene oxide gas into micro-bubbles at the micron level;

a second hydrodynamic micro-interface generator is arranged in the enhanced hydration reaction rectifier; a material outlet is formed at the bottom of the hydration reaction rectifier; the material outlet is connected with a first reboiler; the material discharged from the material outlet is divided into a gas-liquid two-stream material flow through the first reboiler, the gas-phase material flow enters the enhanced hydration reaction rectifier through the second hydrodynamic micro-interface generator, and the liquid-phase material flow directly flows into the enhanced hydration reaction rectifier;

the bottom of the enhanced hydration reaction rectifier is provided with an ethylene glycol outlet for discharging ethylene glycol product, the ethylene glycol discharged from the ethylene glycol outlet is divided into a gas-liquid two-stream material flow through a second reboiler, the gas-phase material flow is circulated and returned to the enhanced hydration reaction rectifier, and the liquid-phase material flow flows into the evaporation tower for gas-liquid separation.

2. The enhanced reaction system for preparing ethylene glycol by the gas-phase catalytic hydration method according to claim 1, wherein the pneumatic micro-interface generator in the hydration reaction rectifier is opposite to the outlet of the first hydraulic micro-interface generator, and the outlets of the pneumatic micro-interface generator and the first hydraulic micro-interface generator are both provided with a guide disc for uniformly distributing generated micro-bubbles.

3. The enhanced reaction system for preparing ethylene glycol by the gas-phase catalytic hydration method according to claim 2, wherein the guide disc is tapered; a plurality of guide holes are uniformly distributed on the guide disc.

4. The enhanced reaction system for preparing ethylene glycol by gas-phase catalytic hydration according to claim 1, wherein a screen for uniformly distributing generated micro-bubbles is arranged at an outlet of the second hydrodynamic micro-interface generator inside the enhanced hydration reaction rectifier.

5. The enhanced reaction system for preparing the ethylene glycol by the gas-phase catalytic hydration method according to the claim 1, wherein the bottom of the enhanced hydration reaction rectifier is provided with a liquid inlet for introducing water.

6. The system of claim 1, wherein the evaporation tower is connected to a dehydration tower, the material from the bottom of the evaporation tower is divided into two gas-liquid streams by a third reboiler, the gas stream is recycled to the evaporation tower, and the liquid stream is further separated and purified in the dehydration tower.

7. The enhanced reaction system for preparing ethylene glycol by the gas-phase catalytic hydration method according to claim 5, wherein a refining tower is connected with the dehydration tower for further refining and purifying the material discharged from the dehydration tower.

8. The enhanced reaction system for preparing ethylene glycol by the gas-phase catalytic hydration method as claimed in claim 6, wherein the refining tower is connected with a product storage tank, and the product flow refined by the refining tower is stored in the product storage tank.

9. The reaction method of the enhanced reaction system for preparing the ethylene glycol by the gas-phase catalytic hydration method of any one of the claims 1 to 8, which is characterized by comprising the following steps:

mixing ethylene oxide and water, dispersing and crushing the mixture through a micro interface, carrying out catalytic hydration reaction, and then carrying out separation, purification and refining to obtain ethylene glycol; the temperature of the catalytic hydration reaction is 150 ℃ and 165 ℃, and the pressure is 0.5-0.8 MPa.

10. The reaction method of claim 9, wherein the catalyst for catalyzing the hydration reaction is any one or more of potassium carbonate, potassium bicarbonate, aluminum perchlorate and aluminum trifluoromethanesulfonate.

Technical Field

The invention relates to the field of ethylene glycol preparation, in particular to a reinforced reaction system and a method for preparing ethylene glycol by a gas-phase catalytic hydration method.

Background

Ethylene glycol is important aliphatic diol, has wide application, and is mainly used for producing polyester resin including fiber, film and engineering plastic. It can also be directly used as a cooling agent and an antifreezing agent, and is also an indispensable substance for producing products such as alkyd resin, plasticizer, paint, adhesive, surfactant, explosive, capacitor electrolyte and the like.

Ethylene oxide is used as a raw material to prepare ethylene glycol, and the method mainly comprises two methods, namely a direct hydration method, namely the ethylene oxide directly reacts with water under certain conditions to generate ethylene glycol, the reaction can be carried out without a catalyst, and the method comprises two methods, namely catalytic hydration and non-catalytic hydration; the other method is an ethylene carbonate method, namely ethylene oxide firstly reacts with CO2 to generate ethylene carbonate under the action of a catalyst, and then ethylene glycol is generated by hydrolysis.

At present, the non-catalytic hydration process of a direct hydration method, also called pressurized hydration, is adopted for industrially preparing the ethylene glycol, a catalyst is not used in the method, the molar ratio of reaction feed water to ethylene oxide (hereinafter referred to as water ratio) is 20-25: 1, the reaction temperature is 150-200 ℃, the reaction pressure is 0.8-2.0 MPa, the conversion rate of the ethylene oxide is close to 100%, and the selectivity of the ethylene glycol is about 90%. In the reaction, because the reactivity of ethylene glycol and ethylene oxide is higher than that of water and ethylene oxide, unconverted ethylene oxide continues to react with the product ethylene glycol to generate diethylene glycol, triethylene glycol and other byproducts, so that a method of large excess of water is often adopted in industry to improve the selectivity of ethylene glycol. The greatest disadvantage of this process is that a large amount of energy is used in the production to evaporate more than 85% of the water in the product. For example, in the purification step of ethylene glycol product, when the feed water ratio is 20, about 19 times of the useless water of ethylene glycol is removed by evaporation, and the required heat is 170 kilocalories per mole of ethylene glycol, which means that about 5.5 tons of steam is consumed for producing 1 ton of ethylene glycol, resulting in huge energy consumption and high production cost of the method. Therefore, in order to reduce the reaction water ratio and reduce the energy consumption, researchers at home and abroad compete to develop the research on various ethylene oxide catalytic hydration reaction technologies.

In the earliest method for producing ethylene glycol by industrial catalytic hydration, when inorganic acid or alkali is used as a catalyst, such as sulfuric acid or phosphoric acid, the ethylene oxide can be completely converted, the yield of ethylene glycol is about 90%, but the inorganic acid catalyst causes corrosion to equipment and pollutes the environment; when inorganic base is used as the catalyst, the generation of some high molecular weight by-products is easily promoted, and the product selectivity is reduced. Therefore, although acid and alkali have obvious catalytic action on the hydration of ethylene oxide, the traditional acid-alkali catalytic hydration process is eliminated and is not used any more.

In order to overcome the defects of catalytic hydration of inorganic acid and alkali, various improvements and researches on a method and a catalyst for catalytic hydration of ethylene oxide are carried out.

Ion exchange resins are used as catalysts, one being strongly acidic cation exchange resins with-SO 3H, -PO (OH)2 groups, the other being basic anion exchange resins containing quaternary ammonium salts, and anion exchange resins based on the catalysis of metal oxyacid groups. For example, U.S. Pat. No. 5,874,653 discloses an anion exchange resin with quaternary ammonium groups crosslinked with styrene and divinylbenzene as an ethylene oxide hydration catalyst. The reaction is carried out at the reaction temperature of 80-200 ℃, the reaction pressure of 200-3000 KPa and the water ratio of 1-15: 1, the conversion rate of the ethylene oxide is close to 100%, and the selectivity of the ethylene glycol is 95%. However, the catalyst system has the obvious defects that the resin catalyst has poor heat resistance, and even if the temperature is in a lower temperature range (less than 95 ℃), the expansion of the catalyst is still serious, so that the pressure drop of a reactor bed layer rises quickly, the catalyst is replaced frequently, and the disadvantages are brought to industrial production. Thus, despite the great progress made by the above-mentioned research work, it still limits its application range. The compound of heteropolyacid salt is used as a catalyst, for example, JP82106631 discloses a K2MoO4-KI catalyst, ethylene oxide and carbon dioxide are reacted at 160 ℃ to generate ethylene carbonate, the conversion rate of the ethylene oxide is 99.9%, and the selectivity of ethylene glycol is 100%; then, under the conditions of reaction temperature of 140 ℃ and reaction pressure of 2.25MPa, the alumina is used as a catalyst, and the ethylene glycol product is obtained by hydrolysis, wherein the conversion rate of the ethylene oxide is 100 percent, and the selectivity of the ethylene glycol is 99.8 percent. The use of the heteropolyacid salt catalyst has the remarkable characteristics that: when the catalyst can be dissolved in water, the conversion rate of the ethylene oxide and the product selectivity are higher, but the catalyst is easy to run off, and unnecessary troubles are brought to the post-treatment process; when the catalyst is insoluble in water, the conversion rate of the ethylene oxide is obviously reduced, and the selectivity of the ethylene glycol is poor. Japanese patent laid-open No. H06-179633 discloses a process for producing an aryl glycol, wherein an aryl oxirane is treated with niobic acid in water and an aqueous solvent, and the epoxy ring moiety in the aryl oxirane is efficiently hydrolyzed with the use of the niobic acid catalyst, whereby the yield of the aryl glycol is 95% or more. However, the method has the disadvantages that the water ratio is too high, and the existence of a large amount of water brings huge energy consumption for the separation of the ethylene glycol product. Japanese patent laid-open No. Hei 7-53219 describes a niobic acid pellet and a process for producing the same. The niobic acid prepared by the method can stably exist for a long time under hydrothermal conditions. But the acidity of the niobic acid catalyst is too strong, and more than 50 percent of the acidity is H0: and the acid content is below 5.6, so that the method is not suitable for the reaction of preparing ethylene glycol by ethylene oxide catalytic hydration.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a reinforced reaction system for preparing ethylene glycol by a gas-phase catalytic hydration method, which effectively ensures full reaction of ethylene oxide and water by arranging a hydration reaction rectifier and a reinforced hydration reaction rectifier connected in series with the hydration reaction rectifier, and ensures that the ethylene oxide is broken into micro-bubbles before the ethylene oxide and the water carry out catalytic hydration reaction by arranging a pneumatic micro-interface generator and a first hydraulic micro-interface generator inside the hydration reaction rectifier and arranging a second hydration reaction rectifier inside the reinforced hydration reaction rectifier, so that the phase boundary mass transfer area between the ethylene oxide and the water is increased, the reaction efficiency is increased, the addition amount of a catalyst is reduced, the energy consumption is low, and the production cost is low.

The second purpose of the invention is to provide a reaction method for preparing ethylene glycol by adopting the reaction system, the ethylene glycol obtained by the reaction has high purity and wide application, the application range of the ethylene glycol is improved, and the method is worthy of wide popularization and application.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a reinforced reaction system for preparing ethylene glycol by a gas-phase catalytic hydration method, which comprises the following steps: a hydration reaction rectifier, an enhanced hydration reaction rectifier and an evaporation tower; an ethylene oxide inlet is formed in the side wall of the hydration reaction rectifier; the bottom of the hydration reaction rectifier is provided with a water inlet;

a pneumatic micro-interface generator and a first hydraulic micro-interface generator are arranged in the hydration reaction rectifier, and the pneumatic micro-interface generator is arranged below the first hydraulic micro-interface generator; the pneumatic micro-interface generator and the first hydraulic micro-interface generator are both connected with the ethylene oxide inlet and are used for crushing ethylene oxide gas into micro-bubbles at the micron level;

a second hydrodynamic micro-interface generator is arranged in the enhanced hydration reaction rectifier; a material outlet is formed at the bottom of the hydration reaction rectifier; the material outlet is connected with a first reboiler; the material discharged from the material outlet is divided into a gas-liquid two-stream material flow through the first reboiler, the gas-phase material flow enters the enhanced hydration reaction rectifier through the second hydrodynamic micro-interface generator, and the liquid-phase material flow directly flows into the enhanced hydration reaction rectifier;

the bottom of the enhanced hydration reaction rectifier is provided with an ethylene glycol outlet for discharging ethylene glycol product, the ethylene glycol discharged from the ethylene glycol outlet is divided into a gas-liquid two-stream material flow through a second reboiler, the gas-phase material flow is circulated and returned to the enhanced hydration reaction rectifier, and the liquid-phase material flow flows into the evaporation tower for gas-liquid separation.

In the prior art, the industrial catalytic hydration method for producing ethylene glycol uses inorganic acid or alkali as a catalyst, for example, sulfuric acid or phosphoric acid as the catalyst, ethylene oxide can be completely converted, the yield of ethylene glycol is about 90%, but the inorganic acid catalyst causes corrosion to equipment and pollutes the environment; when inorganic base is used as the catalyst, the generation of some high molecular weight by-products is easily promoted, and the product selectivity is reduced. Patent RU2001901C1 uses a series process of multiple displacement flow reactors, and uses quaternary ammonium polystyrene anion exchanger containing bicarbonate as catalyst to drive reaction, patent US5488184 discloses an ethylene oxide hydrated anion exchange resin catalyst, and uses resin catalyst to drive reaction, patent CN1237953A discloses a method for producing dihydric alcohol, and uses aluminosilicate zeolite, amorphous aluminosilicate and acidic ion exchange resin as catalyst to drive reaction. Therefore, in the prior art, a large amount of catalyst is needed to promote the reaction, the dependence on the catalyst is large, and the production cost is high.

According to the reinforced reaction system for preparing the ethylene glycol, the pneumatic micro-interface generator and the first hydraulic micro-interface generator are arranged in the hydration reaction rectifier, so that ethylene oxide entering the hydration reaction rectifier is dispersed and crushed into micro bubbles, the mass transfer effect is improved, the mass transfer rate is greatly improved, the hydrogenation reaction temperature and pressure are reduced, and the dependence on a catalyst is reduced; the ethylene oxide which is not completely reacted in the hydration reaction rectifier is input into the hydration reaction rectifier by serially connecting the enhanced hydration reaction rectifier, and the ethylene oxide is dispersed and crushed by the second hydraulic micro-interface generator in the enhanced hydration reaction rectifier, so that the residual ethylene oxide can be fully reflected, and the utilization rate of raw materials is improved.

Preferably, the pneumatic micro-interface generator in the hydration reaction rectifier is arranged opposite to the outlet of the first hydraulic micro-interface generator, and the outlets of the pneumatic micro-interface generator and the first hydraulic micro-interface generator are both provided with guide discs for uniformly distributing generated micro-bubbles.

Preferably, the guide disc is conical; a plurality of guide holes are uniformly distributed on the guide disc. Further, the guide curve of the guide disc is any one of a hyperbolic curve, a parabolic curve, two broken lines and a logarithmic curve.

Preferably, a screen for uniformly distributing generated micro bubbles is provided at an outlet of the second hydrodynamic micro interface generator inside the enhanced hydration reaction rectifier.

Preferably, the bottom of the enhanced hydration reaction rectifier is provided with a liquid inlet for introducing water.

The pneumatic micro-interface generator and the first hydraulic micro-interface generator are arranged in the hydration reaction rectifier, wherein the pneumatic micro-interface generator is arranged below the first hydraulic micro-interface generator, ethylene oxide enters the pneumatic micro-interface generator and the first hydraulic micro-interface generator through an ethylene oxide inlet, meanwhile, water enters the hydration reaction rectifier through a liquid inlet, and enters the pneumatic micro-interface generator and the first hydraulic micro-interface generator along with the increase of water in the hydration reaction rectifier and is taken as a medium to be in close contact with the entering ethylene oxide, so that the ethylene oxide can be fully dispersed and crushed, and a primary micro-interface system is respectively carried out in the pneumatic micro-interface generator and the first hydraulic micro-interface generator, so that the dispersion and crushing efficiency is improved. The outlet of the pneumatic micro-interface generator is opposite to the outlet of the first hydraulic micro-interface generator, so that the opposite impact effect can be achieved, and the uniform distribution of micro-bubbles can be realized.

The invention also provides a guide disc at the outlet of the pneumatic micro-interface generator and the first hydraulic micro-interface generator, wherein a plurality of guide holes are uniformly distributed on the guide disc, and the diameters of the guide holes are sequentially increased along the direction far away from the feed inlet. The guide disc can change the running direction of the micro bubbles to ensure that the bubbles are uniformly distributed; meanwhile, the guide holes in the guide disc can also play a role in redistribution of the microbubbles, so that the microbubbles are more uniformly distributed in the hydration reaction rectifier, and the reaction is favorably carried out. Therefore, the micro-interface generator is combined with the guide disc, so that the application effect of the micro-interface generator is improved.

The invention is also provided with an enhanced hydration reaction rectifier connected with the hydration reaction rectifier in series, a second hydrodynamic micro-interface generator is also arranged in the enhanced hydration reaction rectifier, gas phase material flow passing through the first reboiler can be fully dispersed and crushed in the second hydrodynamic micro-interface generator, and a liquid inlet is arranged at the bottom of the enhanced hydration reaction rectifier, and water enters from the liquid inlet to be used as a medium. The outlet of the second hydraulic micro-interface generator is provided with a screen mesh for uniformly distributing generated micro-bubbles in a medium of the enhanced hydration reaction rectifier, which is beneficial to improving the reaction rate. The second hydraulic micro-interface generator is matched with the screen, so that the application effect of the second hydraulic micro-interface generator is improved.

It will be appreciated by those skilled in the art that the micro-interface generator used in the present invention is described in the prior patents of the present inventor, such as the patents of application nos. CN201610641119.6, 201610641251.7, CN201710766435.0, CN106187660, CN105903425A, CN109437390A, CN205833127U and CN 207581700U. The detailed structure and operation principle of the micro bubble generator (i.e. micro interface generator) is described in detail in the prior patent CN201610641119.6, which describes that "the micro bubble generator comprises a body and a secondary crushing member, wherein the body is provided with a cavity, the body is provided with an inlet communicated with the cavity, the opposite first end and second end of the cavity are both open, and the cross-sectional area of the cavity decreases from the middle of the cavity to the first end and second end of the cavity; the secondary crushing member is disposed at least one of the first end and the second end of the cavity, a portion of the secondary crushing member is disposed within the cavity, and an annular passage is formed between the secondary crushing member and the through holes open at both ends of the cavity. The micron bubble generator also comprises an air inlet pipe and a liquid inlet pipe. "the specific working principle of the structure disclosed in the application document is as follows: liquid enters the micro-bubble generator tangentially through the liquid inlet pipe, and gas is rotated at a super high speed and cut to break gas bubbles into micro-bubbles at a micron level, so that the mass transfer area between a liquid phase and a gas phase is increased, and the micro-bubble generator in the patent belongs to a pneumatic micro-interface generator.

In addition, the first patent 201610641251.7 describes that the primary bubble breaker has a circulation liquid inlet, a circulation gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker communicates the feed inlet with the gas-liquid mixture outlet, which indicates that the bubble breakers all need to be mixed with gas and liquid, and in addition, as can be seen from the following drawings, the primary bubble breaker mainly uses the circulation liquid as power, so that the primary bubble breaker belongs to a hydraulic micro-interface generator, and the secondary bubble breaker simultaneously introduces the gas-liquid mixture into an elliptical rotating ball for rotation, thereby realizing bubble breaking in the rotating process, so that the secondary bubble breaker actually belongs to a gas-liquid linkage micro-interface generator. In fact, the micro-interface generator is a specific form of the micro-interface generator, whether it is a hydraulic micro-interface generator or a gas-liquid linkage micro-interface generator, however, the micro-interface generator adopted in the present invention is not limited to the above forms, and the specific structure of the bubble breaker described in the prior patent is only one of the forms that the micro-interface generator of the present invention can adopt. Furthermore, the prior patent 201710766435.0 states that the principle of the bubble breaker is that high-speed jet flows are used to achieve mutual collision of gases, and also states that the bubble breaker can be used in a micro-interface strengthening reactor to verify the correlation between the bubble breaker and the micro-interface generator; moreover, in the prior patent CN106187660, there is a related description on the specific structure of the bubble breaker, see paragraphs [0031] to [0041] in the specification, and the accompanying drawings, which illustrate the specific working principle of the bubble breaker S-2 in detail, the top of the bubble breaker is a liquid phase inlet, and the side of the bubble breaker is a gas phase inlet, and the liquid phase coming from the top provides the entrainment power, so as to achieve the effect of breaking into ultra-fine bubbles, and in the accompanying drawings, the bubble breaker is also seen to be of a tapered structure, and the diameter of the upper part is larger than that of the lower part, and also for better providing the entrainment power for the liquid phase. Since the micro-interface generator was just developed in the early stage of the prior patent application, the micro-interface generator was named as a micro-bubble generator (CN201610641119.6), a bubble breaker (201710766435.0) and the like in the early stage, and is named as a micro-interface generator in the later stage along with the continuous technical improvement, and the micro-interface generator in the present invention is equivalent to the micro-bubble generator, the bubble breaker and the like in the prior art, and has different names.

In summary, the micro-interface generator of the present invention belongs to the prior art, although some bubble breakers belong to the type of pneumatic bubble breakers, some bubble breakers belong to the type of hydraulic bubble breakers, and some bubble breakers belong to the type of gas-liquid linkage bubble breakers, the difference between the types is mainly selected according to the different specific working conditions, and in addition, the connection between the micro-interface generator and the reactor and other equipment, including the connection structure and the connection position, is determined according to the structure of the micro-interface generator, which is not limited.

Preferably, the evaporation tower is connected with a dehydration tower, the material from the bottom of the evaporation tower is divided into a gas-liquid two-stream by a third reboiler, the gas-phase stream is circulated and returned to the evaporation tower, and the liquid-phase stream enters the dehydration tower for further separation and purification. Further, the dehydrating tower is connected with a refining tower for further refining and purifying the material discharged from the dehydrating tower. Through purification, water mixed in the ethylene glycol product can be removed, and the product purity is improved.

Preferably, the refining tower is connected with a product storage tank, and the product flow refined by the refining tower is stored in the product storage tank.

Preferably, the top parts of the hydration reaction rectifier and the enhanced hydration reaction rectifier are both provided with an additive channel for adding a catalyst.

Preferably, the top of the hydration reaction rectifier is connected with a first condenser, and unreacted water and ethylene oxide are condensed by the first condenser and then flow back to the hydration reaction rectifier.

Preferably, a second condenser is arranged at the top of the enhanced hydration reaction rectifier, and the second condenser can condense and reflux unreacted ethylene oxide gas in the enhanced hydration reaction rectifier into the enhanced hydration reaction rectifier.

Preferably, the top of the refining tower is connected with a third condenser, and the gas-phase components at the top of the refining tower are condensed by the third condenser and then refluxed to the top of the refining tower. The top of the refining tower is totally refluxed, and the gaseous ethylene glycol is condensed into a liquid phase through a third condenser and returns to the refining tower through a reflux pipeline.

The invention also provides a reaction method of the enhanced reaction system for preparing the ethylene glycol by applying the gas-phase catalytic hydration method, which comprises the following steps:

mixing ethylene oxide and water, dispersing and crushing the mixture through a micro interface, carrying out catalytic hydration reaction, and then carrying out separation, purification and refining to obtain ethylene glycol; the temperature of the catalytic hydration reaction is 150 ℃ and 165 ℃, and the pressure is 0.5-0.8 MPa.

Preferably, the catalyst for catalyzing the hydration reaction is any one or a mixture of more of potassium carbonate, potassium bicarbonate, aluminum perchlorate and aluminum trifluoromethanesulfonate.

Specifically, the preparation method comprises the steps of arranging the pneumatic micro-interface generator and the first hydraulic micro-interface generator which are connected with the ethylene oxide inlet inside the hydration reaction rectifier, so that the ethylene oxide and the raw material water are crushed into micro-bubbles with the diameter of more than or equal to 1 mu m and less than 1mm before the hydration reaction, the ethylene oxide is contacted with the water in the micro-bubble state, the phase boundary mass transfer area between the ethylene oxide and the water in the hydration reaction process is increased, the ethylene oxide and the water are fully mixed and then subjected to the hydration reaction, the amount of water and a catalyst required by the reaction is reduced, and the reaction efficiency is improved.

The ethylene glycol product obtained by the reaction method has good quality and high yield. And the preparation method has the advantages of low reaction temperature, greatly reduced pressure and remarkably reduced cost.

Compared with the prior art, the invention has the beneficial effects that:

(1) the enhanced reaction system for preparing the ethylene glycol by the gas-phase catalytic hydration method effectively ensures that the ethylene oxide and the water fully react by arranging the hydration reaction rectifier and the enhanced hydration reaction rectifier connected in series with the hydration reaction rectifier;

(2) the pneumatic micro-interface generator and the first hydraulic micro-interface generator are arranged in the hydration reaction rectifier, and the second hydration reaction rectifier is arranged in the enhanced hydration reaction rectifier, so that the ethylene oxide is crushed into micro bubbles before the ethylene oxide and water carry out catalytic hydration reaction, the phase boundary mass transfer area between the ethylene oxide and the water is increased, the reaction efficiency is increased, the addition amount of the catalyst is reduced, the energy consumption is low, and the production cost is low;

(3) the reaction method is simple and convenient to operate, the ethylene glycol obtained by the reaction has high purity and wide application, the application range of the ethylene glycol is improved, and the method is worthy of wide popularization and application.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic structural diagram of an enhanced reaction system for preparing ethylene glycol by a vapor-phase catalytic hydration method according to an embodiment of the present invention.

Wherein:

10-a hydration reaction rectifier; 101-a dosing channel;

102-a first hydraulic micro-interface generator; 103-a guiding disc;

104-ethylene oxide inlet; 105-a pneumatic micro-interface generator;

106-water inlet; 107-a first condenser;

108-a first reboiler; 109-material outlet;

20-enhanced hydration reaction rectifier; 201-a second hydrodynamic micro-interface generator;

202-screen mesh; 203-ethylene glycol outlet;

204-a second reboiler; 205-a second condenser;

30-an evaporation column; 301-a third reboiler;

40-a dehydration column; 401-a fourth reboiler;

50-a refining tower; 501-a third condenser;

502-a fifth reboiler; 60-product storage tank;

a 70-ethylene oxide storage tank; 80-a water storage tank;

90-water pump.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In order to more clearly illustrate the technical solution of the present invention, the following description is made in the form of specific embodiments.

Examples

Referring to fig. 1, the embodiment provides an enhanced reaction system for preparing ethylene glycol by a gas phase catalytic hydration method, including: a hydration reaction rectifier 10, an intensified hydration reaction rectifier 20 and an evaporation tower 30; an ethylene oxide inlet 104 is arranged on the side wall of the hydration reaction rectifier 10; the bottom of the hydration reaction rectifier 10 is provided with a water inlet 106; the ethylene oxide inlet 104 is connected with the ethylene oxide storage tank 70; the water inlet 106 is connected to the water storage tank 80, and the water pump 90 is disposed between the water storage tank 80 and the water inlet 106.

Wherein, the top parts of the hydration reaction rectifier 10 and the reinforced hydration reaction rectifier 20 are both provided with an additive channel 101 for adding catalyst. The top of the hydration reaction rectifier 10 is also connected with a first condenser 107, and unreacted water and ethylene oxide are condensed by the first condenser 107 and then flow back to the hydration reaction rectifier 10. A pneumatic micro-interface generator 105 and a first hydraulic micro-interface generator 102 are arranged in the hydration reaction rectifier 10, and the pneumatic micro-interface generator 105 is arranged below the first hydraulic micro-interface generator 102; the pneumatic micro-interface generator 105 and the first hydraulic micro-interface generator 102 are both connected with the ethylene oxide inlet 104 for breaking the ethylene oxide gas into micro-bubbles at the micron level; specifically, the pneumatic micro-interface generator 105 in the hydration reaction rectifier 10 is arranged opposite to the outlet of the first hydraulic micro-interface generator 102, and the outlets of the pneumatic micro-interface generator 105 and the first hydraulic micro-interface generator 102 are both provided with a guide disc 103 for uniformly distributing generated micro-bubbles.

The guide disc 103 is conical; a plurality of guide holes are uniformly distributed on the guide disc 103. Further, the guide curve of the guide disk 103 is any one of a hyperbolic curve, a parabolic curve, a two-segment broken line and a logarithmic curve.

A second hydrodynamic micro-interface generator 201 is arranged in the enhanced hydration reaction rectifier 20; at the outlet of the second hydrodynamic micro-interface generator 201, a screen 202 is arranged for evenly distributing the generated micro-bubbles. The bottom of the hydration reaction rectifier 10 is provided with a material outlet 109; the material outlet 109 is connected with a first reboiler 108; the material discharged from the material outlet 109 is divided into a gas-liquid two-stream material flow by the first reboiler 108, the gas-phase material flow enters the enhanced hydration reaction rectifier 20 through the second hydraulic micro-interface generator 201, and the liquid-phase material flow directly flows into the enhanced hydration reaction rectifier 20;

the bottom of the enhanced hydration reaction rectifier 20 is provided with an ethylene glycol outlet 203 for discharging the product ethylene glycol, the ethylene glycol discharged from the ethylene glycol outlet 203 is divided into two gas-liquid material flows through a second reboiler 204, the gas-phase material flow is circulated and returned to the enhanced hydration reaction rectifier 20, and the liquid-phase material flow flows into the evaporation tower 30 for gas-liquid separation. The bottom of the enhanced hydration reaction rectifier 20 is provided with a liquid inlet for introducing water. The liquid inlet is connected with a water storage tank 80.

In addition, a second condenser 205 is further disposed at the top of the enhanced hydration reaction rectifier 20, and the second condenser 205 is capable of condensing and refluxing unreacted ethylene oxide gas in the enhanced hydration reaction rectifier 20 to the enhanced hydration reaction rectifier 20.

In this embodiment, the evaporation tower 30 is connected to the dehydration tower 40, the material from the bottom of the evaporation tower 30 is divided into two gas-liquid streams by the third reboiler 301, the gas phase stream is circulated back to the evaporation tower 30, and the liquid phase stream enters the dehydration tower 40 for further separation and purification. Further, the dehydrating tower 40 is connected with a refining tower 50 for further refining and purifying the material discharged from the dehydrating tower 40. Through purification, water mixed in the ethylene glycol product can be removed, and the product purity is improved. The refining tower 50 is connected to a product storage tank 60, and the product stream refined by the refining tower 50 is sent to the product storage tank 60 to be stored.

The top of the refining tower 50 is connected with a third condenser 501, and gas-phase components at the top of the refining tower flow back to the top of the refining tower 50 after being condensed by the third condenser 501. The top of the refining tower 50 is totally refluxed, and the gaseous ethylene glycol is condensed into a liquid phase through the third condenser 501 and returns to the refining tower through a reflux pipeline.

Wherein a fourth reboiler 401 is arranged between the dehydrating tower 40 and the refining tower 50; a fifth reboiler 502 is provided within finishing column 50 and product storage tank 60. The fourth reboiler 401 and the fifth reboiler 502 gasify part of the passing material, the liquid phase is continuously output, and the gas phase is refluxed, thereby further purifying the material.

In addition, the top of the hydration reaction rectifier 10 is connected with the second reboiler 204, the top of the enhanced hydration reaction rectifier 20 is connected with the third reboiler 301, the top of the evaporation tower 30 is connected with the fourth reboiler 401, and the top of the dehydration tower 40 is connected with the fifth reboiler 502, so that the steam of the previous stage can be used as the heat source of the reboiler of the next stage, and the utilization efficiency of energy is improved.

In the specific reaction process, 20g of catalyst, 200g of ethylene oxide and 600g of water are introduced into a hydration reaction rectifier 10, the hydration reaction rectifier 10 is heated to 150 ℃, and the pressure of the water and the reactor is set to be 0.7 MPa. Ethylene oxide and water react in the hydration reaction rectifier 10, and the reacted materials flow into the enhanced hydration reaction rectifier 20 to continue the hydration reaction; the produced ethylene glycol flows out from the enhanced hydration reaction rectifier 20, is dehydrated by the evaporation tower 30 and the dehydration tower 40, is refined and purified in the refining tower 50, and the purified ethylene glycol is output to the product storage tank 60.

In a word, compared with the reaction system for preparing the ethylene glycol by the gas-phase catalytic hydration method in the prior art, the enhanced reaction system disclosed by the invention has the advantages of fewer equipment components, small occupied area, low energy consumption, low cost, high safety, controllable reaction and high raw material conversion rate, is equivalent to providing a reaction system with stronger operability for the field of ethylene glycol preparation, and is worthy of wide popularization and application.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.