CN102093312B - Epoxyethane synthesis method and production device thereof - Google Patents

Abstract

The invention discloses a method for synthesizing ethylene oxide, which comprises the following steps: 1) loading ethylene glycol into a metering tank (20);

(2) Nitrogen is set inside, and the high-pressure gas storage tank (1) Hydrogen is installed inside; 2), the activated supported catalyst (24) is placed in the fixed bed reactor (26), and the high-pressure gas storage tank

Part of the nitrogen in (2) directly enters the vaporization chamber (12), and the other part drives the ethylene glycol in the metering tank (20) into the vaporization chamber (12) for preheating and vaporization; the vaporized nitrogen in the vaporization chamber (12) The mixture of nitrogen and ethylene glycol enters the fixed-bed reactor (26) to carry out dehydration reaction under the action of the activated supported catalyst (24); 3), the product obtained from the dehydration reaction is condensed and collected to obtain epoxy ethane. Adopting the method of the invention to synthesize ethylene oxide has the advantages of convenient transportation of raw materials, high yield and the like.

Description

Synthetic method and used production equipment of ethylene oxide

technical field

The present invention relates to a synthesis method of epoxy compound and the used production device, especially the synthesis method of ethylene oxide and the used production device.

Background technique

Ethylene oxide is an organic compound with a chemical formula of C ₂ H ₄ O. It is a toxic carcinogen. It is a colorless and flammable gas at normal temperature and pressure, and a colorless and easy-flowing liquid at low temperature. Ethylene oxide can be used as organic chemical raw materials and solvents, mainly used in the manufacture of various other solvents, diluents, non-ionic surfactants, synthetic detergents, antifreeze agents, disinfectants, tougheners and plasticizers, etc. ; It has a bactericidal effect and does not corrode metals, so it can be used as a gas bactericide; when it decomposes, it generates huge energy and can be used as a rocket jet propulsion power.

The existing synthetic methods of ethylene oxide generally include chlorohydrin method and oxidation method.

The chlorohydrin method is to pass ethylene and chlorine gas into water to generate chlorohydrin, and then react with alkali (usually milk of lime) with chlorohydrin to carry out cyclization. The reaction temperature is controlled at about 100°C, and the generated ethylene oxide leaves the reaction zone as soon as possible, flows out from the condensation port on the upper part of the reactor, and then separates vapor from liquid and distills to obtain the finished product with a yield of 60-70%.

The oxidation method is produced by direct oxidation of ethylene and air or oxygen through a silver catalyst in the gas phase at 200-300 ° C and 1-3 MPa pressure. Oxidation catalysts generally contain 10-30% silver, and effective catalysts are alkali metals and alkaline earth metals. The commonly used carrier is alumina or silicon carbide. After the reaction, oxidizing gas is generated, which is absorbed with water in the absorption tower, and the unreacted ethylene is recycled back to the reactor. The absorption liquid is desorbed and distilled to obtain the product, and the yield is about 50%.

Both the chlorohydrin method and the oxidation method use ethylene as the initial raw material, and ethylene is a flammable and explosive gas at room temperature, and ethylene oxide is also a flammable and explosive low-boiling substance. In some regions, whether ethylene oxide is transported from other places or ethylene oxide is directly produced locally, there are problems such as high cost and high risk in the transportation process.

The patent application number 01135931.5 uses a closed-cycle packed tower reactor to prepare a mixture of ethylene oxide and propylene oxide; it uses a packed tower as a reactor to generate ethylene oxide by the reaction of ethylene glycol and sodium hydroxide. It does not use a catalyst, but uses sodium hydroxide to react with ethylene glycol to dehydrate it, and sodium hydroxide, as a strong base, has a strong corrosive effect on equipment, so it is not suitable for large-scale production.

Contents of the invention

The technical problem to be solved by the present invention is to provide a production method and production device for ethylene oxide, which has the advantages of convenient transportation of raw materials, simple synthesis process and high yield.

In order to solve the problems of the technologies described above, the invention provides a kind of synthetic method of oxirane, comprises the following steps successively:

1), ethylene glycol is packed in the metering tank; Nitrogen is set in the high-pressure gas storage tank II, and hydrogen is set in the high-pressure gas storage tank I;

2) An activated supported catalyst is placed in the fixed bed reactor, part of the nitrogen in the high-pressure gas storage tank II directly enters the vaporization chamber, and the other part drives the ethylene glycol in the metering tank into the vaporization chamber for preheating and vaporization; vaporization The mixture of vaporized nitrogen and ethylene glycol in the room enters the fixed-bed reactor together to carry out dehydration reaction under the action of activated supported catalyst; the reaction temperature in the dehydration reaction is 200-280°C, and the reaction pressure is 0.2-1.0Mpa. Ethylene glycol volume space velocity is 0.1～0.4h ^-1 ;

3) Condensing and collecting the product obtained from the dehydration reaction to obtain ethylene oxide.

As an improvement of the synthesis method of ethylene oxide of the present invention: the preheating temperature of the vaporization chamber is 180-220°C.

As a further improvement of the synthesis method of ethylene oxide of the present invention: the preparation method of the activated supported catalyst is as follows: first, the supported catalyst is composed of a metal salt and a carrier, and then under the action of hydrogen and/or nitrogen at 10 to 300 ℃; the metal salt is at least two of copper salt, nickel salt and cobalt salt, the sum of the metals accounts for 29% to 38% of the total weight of the supported catalyst, and each metal must not be less than the supported catalyst 5% of the total weight.

As a further improvement of the synthesis method of ethylene oxide in the present invention: the carrier is gamma-alumina, activated carbon or zeolite molecular sieve.

As a further improvement of the synthesis method of ethylene oxide of the present invention: the metal salt is a nitrate.

As a further improvement of the synthesis method of ethylene oxide of the present invention: the metal salt and the carrier are sequentially impregnated, dried, and roasted to make a supported catalyst; the drying step is 120 ° C for 5 hours, and the roasting step is 400 ° C to 450 ° C. 4h.

The present invention also simultaneously provides a production device for realizing the above synthesis method, comprising a high-pressure gas storage tank I for providing high-pressure hydrogen, a high-pressure gas storage tank II for providing high-pressure nitrogen, a metering tank for providing ethylene glycol, and a heating tank. The vaporization chamber of the device, the fixed bed reactor provided with the heating device and the pressure reducing valve I and pressure reducing valve II for controlling the dehydration reaction pressure, the vaporization chamber is connected with the fixed bed reactor; After the pressure valve I is connected to the connecting pipe, the outlet of the high-pressure gas storage tank II is connected to the connecting pipe after passing through the pressure reducing valve II; the outlet end of the connecting pipe is connected to the inlet end of the metering tank through the inlet pipe, and the outlet of the metering tank is It is connected to the collecting pipe; the outlet end of the connecting pipe is also connected to the collecting pipe through a pipeline; the outlet end of the collecting pipe is connected to the inlet end of the fixed bed reactor after passing through the vaporization chamber; the inlet end and the outlet end of the fixed bed reactor are respectively set Inert packing, the middle section of the fixed-bed reactor is placed with an activated supported catalyst; the outlet of the fixed-bed reactor is sequentially connected to the stop valve IV, the condenser, the stop valve V and the collecting device;

There is a shut-off valve I on the pipeline, a shut-off valve II on the inlet pipe, and a shut-off valve III and a flow meter on the outlet pipe according to the flow direction of the material.

As an improvement of the production device of the present invention: the heating device of the fixed bed reactor is a heating jacket placed on the outer surface of the fixed bed reactor, and the heating jacket is provided with a reactor thermometer; the vaporization chamber is provided with a pressure gauge and a vaporization chamber thermometer.

The product obtained by the dehydration cyclization reaction of the present invention is condensed and absorbed by a small amount of water, and the condensate obtained by gas chromatography analysis can be carried out at regular intervals, and can be easily detected to contain ethylene oxide, ethanol, 1,4-bis Oxygen hexane and other components; the aqueous solution that has absorbed ethylene oxide is distilled in a distillation tower with an absolute pressure of 5 bar and a temperature of 60 degrees. The top or side stream of the tower flows out to obtain ethylene oxide.

The synthetic method of oxirane of the present invention has found a new method for preparing oxirane, and the reaction formula is as follows:

The invention uses ethylene glycol as a raw material, which is simple, non-toxic and easy to transport. Although on the surface, the price of raw material ethylene glycol is not much different from that of ethylene oxide, but due to the simplicity of storage and transportation, the preparation of ethylene oxide from ethylene glycol has certain practical significance.

The synthetic method of oxirane of the present invention has the following advantages:

1) The raw materials are simple and safe, suitable for long-distance mass transportation;

2), changing the existing production process to a fixed bed continuous production process, realizing continuous mass production;

3), the production method of the present invention has simple equipment, convenient operation, easy control of reaction conditions, high yield and good product quality; therefore, large-scale production can be realized industrially only with a small amount of investment.

In summary, the production of ethylene oxide by the method of the present invention has the advantages of continuous production, simple and harmless raw materials, simple operation process and high yield.

Description of drawings

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of the connection relationship of the production device used in the present invention.

Detailed ways

Specific embodiments of the present invention will be described in detail with reference to the above-mentioned drawings.

Fig. 1 has provided a kind of device that is used to produce ethylene oxide, comprises the high-pressure gas storage tank I1 that provides high-pressure hydrogen, provides the high-pressure gas storage tank II2 of high-pressure nitrogen, provides the metering tank 20 of ethylene glycol, is provided with heating The vaporization chamber 12 of the device, the fixed-bed reactor 26 and the pressure reducing valve I5 and pressure reducing valve II6 for controlling the dehydration reaction pressure.

The outer surface of the fixed bed reactor 26 is covered with a heating jacket 27, and the heating jacket 27 is used to control the reaction temperature in the fixed bed reactor 26, and the heating jacket 27 is provided with a reactor thermometer 25. The vaporization chamber 12 is filled with quartz sand for uniform heating; the vaporization chamber 12 is provided with a pressure gauge 10, and the vaporization chamber 12 is also provided with a vaporization chamber thermometer 11, and the outlet end of the vaporization chamber 12 is connected to the inlet of the fixed bed reactor 26. end connected. Inert filler 23 is set in the inlet end (ie upper section) of fixed bed reactor 26 and the outlet end (ie lower section) of fixed bed reactor 26, and activated supported catalyst 24 is placed in the middle section of fixed bed reactor 26. In the device of the present invention: the fixed bed reactor 26 is a stainless steel reaction tube, its inner diameter Ф=14.0mm, total length 1=1250mm; remove the part of the upper and lower sections filled with inert filler 23, the effective work of the middle section The length is 1100mm, the effective volume is 170-180ml, and the supported catalyst filled in the middle section is generally about 180 grams.

The high-pressure gas storage tank I1 is connected with the inlet end of the connecting pipe 28 through the pipeline 3, and a pressure reducing valve I5 is arranged on the pipeline 3; the high-pressure gas storage tank II2 is connected with the inlet end of the connecting pipe 28 through the pipeline 4, and the Road 4 is provided with pressure reducing valve II6. Pressure reducing valve I5 and pressure reducing valve II6 cooperate to control the ratio of hydrogen and nitrogen in the device. The outlet end of the connecting pipe 28 is divided into two paths, one path is connected to the collecting pipe 21 after passing through the pipeline 18, and a shut-off valve I7 is provided on the pipeline 18, and the shut-off valve I7 is used to control the switch of the pipeline 18; The inlet pipe 19 is connected to the inlet end of the metering tank 20, and a shut-off valve II8 is arranged on the inlet pipe 19, and the outlet end of the metering tank 20 is connected to the collecting pipe 21 through the outlet pipe 22; There is a shut-off valve III9 and a flow meter 17. The stop valve II8 is used to control the switch of the inlet pipe 19, the flow meter 17 is used to control the flow in the outlet pipe 22, and the stop valve III9 is used to control the switch of the outlet pipe 22. The other end of the collecting pipe 21 is connected with the inlet end of the vaporization chamber 12 . The outlet end of the fixed-bed reactor 26 is connected to the shut-off valve IV13, the condenser 14, the shut-off valve V15 and the collection device 16 in sequence. The stop valve IV13 is used to control the switch of the condenser 14, and the stop valve V15 is used to control the switch of the collecting device.

In order to ensure that the supported catalyst can be activated in the device of the present invention, the device of the present invention is specially provided with two gas storage tanks (that is, the high-pressure gas storage tank I1 that provides high-pressure hydrogen and the high-pressure gas tank that provides high-pressure nitrogen) that provide nitrogen and hydrogen. Gas storage tank II2), which meets the requirements of catalyst activation with hydrogen and nitrogen in the same device and catalyst participation in the reaction in a hydrogen-free environment.

The production method of oxirane of the present invention, first carries out the preparation of catalyst and activation, specifically as follows:

1. Preparation:

Fully mix and impregnate γ-alumina (specific surface area 220-250m ² g ^-1 ) with mixed solutions of different metal nitrates, dry at room temperature and then dry at 120°C for 5h, then bake at 400°C-450°C for 4h, and cool down naturally , to obtain the desired supported catalyst.

Among them, the supported catalyst A contains 18% Cu and 16% Ni; the supported catalyst B contains 20% Cu and 18% Co; the supported catalyst C contains 19% Cu, 10% Ni and 9% Co; supported catalyst D contains 19% Cu, 5% Ni and 5% Co; supported catalyst E contains 5% Cu, 5% Ni and 19% Co. The above percentages all refer to percentages by weight.

2. Activation:

The above-mentioned supported catalyst is put into the middle section of the fixed bed reactor 26, and the activation treatment is carried out here; to ensure that the activated catalyst is set in the middle section of the fixed bed reactor 26 during the dehydration and cyclization reaction of the following steps. Supported catalysts24.

When it is necessary to use _N2 and _H2 to activate the loaded catalyst at the same time: close the shut-off valve II8 and the shut-off valve III9, so that the pressure reducing valve I5, the pressure reducing valve II6, the shut-off valve I7, the shut-off valve IV13, and the shut-off valve V15 are at open state. The _H2 in the high-pressure gas storage tank I1 flows to the pressure reducing valve I5 through the pipeline 3; the _N2 in the high-pressure gas storage tank II2 flows to the pressure reducing valve II6 through the pipeline 4, and the ratio of nitrogen and hydrogen is controlled cooperatively. The above-mentioned _H2 and _N2 enter into the collecting pipe 21 sequentially through the connecting pipe 28 and the pipeline 18, and the collecting pipe 21 passes the collected _N2 and _H2 successively through the vaporization chamber 12 and the inert filler 23 in the upper section of the fixed bed reactor 26 Finally, activate the supported catalyst in the middle section of the fixed-bed reactor 26 until the activation is completed; at this time, rely on the heating jacket 27 to ensure that the fixed-bed reactor 26 is always heated during the ventilation time. The supported catalysts A to E were all activated under the same conditions described below, and the aeration time, aeration flow rate and heating temperature of different activation time periods are shown in Table 1.

Table 1

(Note: What this table 1 represents is: when the supported catalyst is activated within 24 hours, the process conditions in different time periods.)

Of course, the supported catalyst can also be made into an activated supported catalyst 24 outside the device of the present invention, and then put into the middle section of the fixed-bed reactor 26 for use during the dehydration and cyclization reaction in the following steps.

Embodiment 1, a kind of synthetic method of oxirane, carries out following steps successively:

1) Set nitrogen gas in the high-pressure gas storage tank II2, and set hydrogen gas in the high-pressure gas storage tank I1.

Since the reaction needs to be carried out under the condition of separating hydrogen and oxygen, the pressure reducing valve I5 is closed so that the pressure reducing valve II6, the shut-off valve I7, the shut-off valve II8, the shut-off valve III9, the shut-off valve IV13 and the shut-off valve V15 are all in an open state; Add 300 ml (5.40 mol) of ethylene glycol to tank 20 .

2) The nitrogen in the high-pressure gas storage tank II2 passes through the pipeline 4 and then enters the pressure reducing valve II6 at a flow rate of 100ml/min for decompression treatment. The pressure value set by the pressure reducing valve II6 is the work in the following reaction pressure. After the nitrogen gas coming out from the pressure reducing valve 6 passes through the connecting pipe 28, a part flows directly to the collecting pipe 21 through the pipeline 18, and the other part enters the metering tank 20 through the inlet pipe 19, and the flow rate of ethylene glycol flowing out of the metering tank 20 passes through the flowmeter 17 is controlled; Because go out pipe 22 and pipeline 18 air pressures are identical, then the ethylene glycol in metering tank 20 relies on gravity to drop. The collection pipe 21 sends the collected nitrogen and ethylene glycol into the vaporization chamber 12 for preheating and vaporization. The vaporization chamber 12 relies on its own heating device, and the heating temperature is set at 200°C; after the ethylene glycol is vaporized, it enters the fixed Bed reactor 26; After the uniform mixing of inert filler 23, enter the middle section of fixed bed reactor 26 to react under the effect of activated supported catalyst 24 (which is selected to be supported catalyst C in table 1); during the reaction The reaction temperature is 240°C (set by heating jacket 27), the reaction pressure is 0.6Mpa (set by pressure reducing valve II6), and the volumetric space velocity of the ethylene glycol is controlled to be 0.1h ^-1 (that is, about The reaction was completed in 17 hours).

3) After the reaction is finished, the product obtained from the dehydration and cyclization reaction passes through the inert filler 23 in the lower section of the fixed bed reactor 26 and then enters the condenser 14 for condensation treatment. After the condensate flows out, it enters the collection device 16, and the aqueous solution that has absorbed ethylene oxide is distilled in a distillation tower with an absolute pressure of 5 bar and a temperature of 60 degrees. The top or side cut of the column rectification section flows out, and the yield is 81% (in terms of ethylene glycol).

Change the reaction temperature in embodiment 1, the type of supported catalyst in the middle section of fixed bed reactor 26, the reaction pressure and the volume space velocity of ethylene glycol; all the other steps are the same as embodiment 1, and obtain embodiment 2～embodiment 6 respectively. The yield of the obtained ethylene oxide is shown in Table 2.

Table 2

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (4)

1. the synthetic method of oxyethane is characterized in that may further comprise the steps successively:

1), ethylene glycol is packed in the test tank (20); At high pressure tank II(2) in nitrogen is set, at high pressure tank I(1) in hydrogen is set;

2), place the loaded catalyst (24) through overactivation, high pressure tank II(2 in the fixed-bed reactor (26)) in a nitrogen part directly enter vaporizing chamber (12), another part and drive ethylene glycol in the test tank (20) and enter together vaporizing chamber (12) and carry out the preheating vaporization; Nitrogen after the vaporization in the above-mentioned vaporizing chamber (12) and the mixture of ethylene glycol together enter fixed-bed reactor (26) and carry out dehydration reaction under the effects of the loaded catalyst (24) of activation; Temperature of reaction is 200～280 ℃ in the described dehydration reaction, and reaction pressure is 0.2～1.0Mpa, and described ethylene glycol volume space velocity is 0.1 ~ 0.4h ^-1

The preparation method of the loaded catalyst of described activation (24) is as follows: first form loaded catalyst by metal-salt and carrier, make activating between 10～300 ℃ under the effect of hydrogen and nitrogen; Described metal-salt is at least two kinds in mantoquita, nickel salt and the cobalt salt, and the metal sum accounts for 29%～38% of loaded catalyst gross weight, and every kind of metal must not be less than 5% of loaded catalyst gross weight;

Described metal-salt and carrier are made loaded catalyst through dipping, drying, calcination steps successively; Drying step is 120 ℃ of dry 5h, and calcination steps is 400 ℃ ~ 450 ℃ roasting 4h;

3), the product of dehydration reaction gained is carried out condensation, after the collection, get oxyethane.

2. the synthetic method of oxyethane according to claim 1, it is characterized in that: the preheating temperature of described vaporizing chamber (12) is 180～220 ℃.

3. the synthetic method of oxyethane according to claim 1 and 2, it is characterized in that: described carrier is γ-aluminum oxide, activated carbon or zeolite molecular sieve.

4. the synthetic method of oxyethane according to claim 3, it is characterized in that: described metal-salt is nitrate.