CN214735475U - Device for preparing 6-aminocapronitrile by gas phase method - Google Patents
Device for preparing 6-aminocapronitrile by gas phase method Download PDFInfo
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Abstract
The utility model provides a device of gas phase method preparation 6-aminocapronitrile, the device includes fluidized bed reactor and regenerator, fluidized bed reactor's solid export links to each other with the solid entry of regenerator, the solid export of regenerator links to each other with fluidized bed reactor's solid entry, the bottom of regenerator is equipped with the regeneration gas entry. The utility model uses the fluidized bed reactor and the regenerator together, can realize the regeneration and the utilization of the catalyst when preparing the 6-aminocapronitrile, and avoids the problem of poor operation stability of the device caused by the inactivation of the catalyst; the 6-aminocapronitrile is prepared by adopting a gas phase method, the contact area between the reaction raw material and the catalyst is large, the heat and mass transfer effects are good, the catalyst is synchronously regenerated, the defects of quick attenuation of the activity of the catalyst and short service life are overcome, and the conversion rate of the raw material and the selectivity of the product are improved; the device has the advantages of simple structure, low cost and good economy.
Description
Technical Field
The utility model belongs to the technical field of organic synthesis, a device of vapor phase method preparation 6-aminocapronitrile is related to.
Background
Hexamethylenediamine is an important chemical product, is mainly used for producing polyamide, synthesizing polyurethane resin, ion exchange resin and diisocyanate, is used as a curing agent of urea resin, epoxy resin and the like, an organic cross-linking agent and the like, can be used as an adhesive, a stabilizer, a bleaching agent, an anti-corrosion agent and the like, and is widely applied to the fields of organic synthesis, aerospace, textile papermaking, metal materials and the like. The main source of the hexamethylene diamine is 6-aminocapronitrile, and the 6-aminocapronitrile is an important chemical intermediate and can be hydrogenated to prepare the hexamethylene diamine, so that the preparation of the 6-aminocapronitrile becomes an important step on a hexamethylene diamine production line.
At present, the synthesis of 6-aminocapronitrile mainly takes caprolactam as a raw material and is prepared by ammoniation dehydration reaction, and the synthesis comprises two major types of gas phase method and liquid phase method; the reaction needs a catalyst, water which is a byproduct of the reaction catalyzes caprolactam to polymerize, the generated polymer blocks catalyst pore channels, the activity of the catalyst is reduced, in addition, tar and carbon deposition are easily generated in high-temperature reaction and cover the surface of the catalyst, the active sites of the catalyst are further reduced, the catalyst is gradually inactivated, and the running stability of a reaction device is poor.
CN 107739318A discloses a method and a device for preparing 6-aminocapronitrile by a caprolactam liquid phase method, which comprises the following steps: s1: mixing caprolactam, an organic solvent and a catalyst to obtain a mixed solution, adding the mixed solution into a reaction kettle, and stirring and heating the mixed solution; s2: when the mixed solution reaches a certain temperature, introducing ammonia gas into the mixed solution for reaction; s3: after the reaction is finished, rectifying and purifying the reaction product to obtain pure 6-aminocapronitrile. The liquid phase method adopts phosphoric acid or phosphate as a catalyst, and the phosphorus-containing catalyst is difficult to recover after being used and does not relate to the regeneration and the utilization of the catalyst; the reaction has higher requirement on the corrosion resistance of equipment, and can generate phosphorus-containing wastewater after rectification, thereby increasing the subsequent treatment operation.
CN 111004148A discloses a method for preparing 6-aminocapronitrile by a gas phase method, which comprises the following steps: respectively preheating caprolactam and ammonia gas after metering, mixing, further heating to obtain a mixture, putting the mixture into a reactor, carrying out an ammoniation dehydration reaction in the presence of a catalyst to obtain an ammoniation reactant, wherein the catalyst consists of alkaline earth metal salt or transition metal salt serving as an active component and titanium dioxide or a ZSM-5 molecular sieve serving as a carrier, and finally separating and purifying to obtain the target product 6-aminocapronitrile. The method still takes reaction and purification as main steps, and does not relate to the regeneration treatment of the catalyst and how to solve the problem of the reduction of the activity of the catalyst.
CN 111646921A discloses a catalyst regeneration method for preparing a hexamethylene diamine key intermediate 6-aminocapronitrile by a caprolactam method, which mainly comprises the step of carrying out hydrolysis treatment or dissolution treatment on a catalyst to be regenerated, wherein the used solution is an acidic solution, an alkaline solution or an organic solution, but the regeneration of the catalyst in the method cannot be carried out synchronously with the reaction, the stable operation time of a reaction device is not improved, and the process involved in the process is complicated and is not beneficial to industrial implementation.
In summary, for the catalytic preparation of 6-aminocapronitrile, it is also necessary to be able to realize the synchronous reaction and catalyst regeneration in the same device, overcome the problem of fast catalyst activity decay, and ensure the long-time continuous operation of the reaction device.
SUMMERY OF THE UTILITY MODEL
Aiming at the problems in the prior art, the utility model aims to provide a device for preparing 6-aminocapronitrile by a gas phase method, which uses a fluidized bed reactor and a regenerator together, can realize the regeneration and utilization of a catalyst when preparing 6-aminocapronitrile, avoids the problem of poor operation stability of the device caused by the inactivation of the catalyst, ensures the uniform and stable reaction, and improves the conversion rate and the product selectivity of raw materials; the device has the advantages of simple structure, low cost and wide application prospect.
To achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a device of gas phase method preparation 6-aminocapronitrile, the device includes fluidized bed reactor and regenerator, fluidized bed reactor's solid export links to each other with the solid entry of regenerator, the solid export of regenerator links to each other with fluidized bed reactor's solid entry, the bottom of regenerator is equipped with the regeneration gas entry.
The utility model discloses in, adopt the gas phase method to prepare 6-aminocapronitrile, the area of contact between reaction raw materials and the catalyst is big in the fluidized bed reactor, and heat and mass transfer is effectual, helps high-efficient synthetic 6-aminocapronitrile, and the setting of regenerator can adopt the catalyst to regenerate in the reaction process, overcomes the defect that the catalyst decay is fast, the life-span is short, guarantees that the device can long-time continuous steady operation, helps improving the conversion rate of raw materials and the selectivity of product; the device has the advantages of simple structure, long service life of the catalyst, good reaction effect and good economy.
Following conduct the utility model discloses preferred technical scheme, nevertheless do not conduct the utility model provides a technical scheme's restriction, through following technical scheme, can reach and realize better the utility model discloses a technical purpose and beneficial effect.
As the preferred technical scheme of the utility model, fluidized bed reactor's upper portion is connected with the riser, the solid export of regenerator is connected to and returns fluidized bed reactor on the riser.
Preferably, the bottom of the fluidized bed reactor is provided with a gaseous mixture inlet, and the top of the riser is a reaction product outlet.
The utility model discloses in, the effect that sets up the riser in fluidized bed reactor's top lies in: the contact time of the catalyst and the raw material is prolonged, and the regenerated catalyst with higher activity is fed into the upper part of the lifting pipe, so that the conversion rate of the raw material is improved, and the catalyst is beneficial to settling back into the fluidized bed reactor.
As the preferred technical scheme of the utility model, be equipped with the valve on the solid export of fluidized bed reactor and the solid entry's of regenerator connecting pipeline.
Preferably, a solid feeding device is arranged on a connecting pipeline between the solid outlet of the regenerator and the solid inlet of the fluidized bed reactor.
The utility model discloses in, set up the valve on the catalyst production pipeline, can control the catalyst the production mode and the production rate, and solid feed arrangement then returns fluidized bed reactor for regenerated catalyst and provides conveying power to guarantee the stability of catalyst transport process and the uniformity of joining speed.
The utility model also provides a method for preparing 6-aminocapronitrile by adopting the device, the method comprises the following steps:
(1) introducing a gaseous mixture of caprolactam and ammonia gas into a fluidized bed reactor, and carrying out amination dehydration reaction under the action of a catalyst to generate 6-aminocapronitrile;
(2) and (2) introducing part of the catalyst extracted in the reaction process in the step (1) into a regenerator, performing regeneration treatment by using oxygen-containing regeneration gas, and returning the regenerated catalyst to the fluidized bed reactor.
As a preferred technical proposal of the utility model, the gaseous mixture in the step (1) also comprises an organic solvent.
Preferably, the organic solvent comprises any one of methanol, ethanol, acetonitrile, toluene or xylene or a combination of at least two of these, typical but non-limiting examples being: a combination of methanol and ethanol, a combination of ethanol and acetonitrile, a combination of toluene and xylene, a combination of methanol, ethanol and acetonitrile, a combination of acetonitrile, toluene and xylene, a combination of methanol, ethanol, acetonitrile and toluene, and the like.
The weight ratio of caprolactam, ammonia gas and organic solvent is preferably 1 (0.2-20): (0-10), for example 1:0.2, 1:10, 1:20, 1:0.5:1, 1:5:1, 1:15:1, 1:0.8:3, 1:8:3, 1:16:3, 1:1:5, 1:10:6, 1:20:10, etc., but is not limited to the recited values, and other values not recited within the range of values are equally applicable, preferably 1 (0.8-5): 0-3.
In the utility model, the adding amount proportion of caprolactam and ammonia gas is an important factor influencing the conversion rate of raw materials, if the weight ratio of caprolactam to ammonia gas is higher, namely the adding amount of ammonia gas is less, the conversion rate of raw materials and the selectivity of products can be reduced, and the activity attenuation of the catalyst is accelerated; if the weight ratio of caprolactam to ammonia is lower, namely the addition amount of ammonia is more, the ammonia consumption or ammonia recycling energy consumption can be increased, and the process economy is not facilitated;
wherein, the organic solvent has the function of relieving the coking degree of the surface of the catalyst and prolonging the service life of the catalyst in the ammoniation dehydration reaction.
As a preferred technical scheme of the utility model, the catalyst in the step (1) comprises an active component and a carrier, wherein the active component comprises phosphoric acid and/or phosphate, and the carrier comprises alumina and/or silica.
Preferably, the active component is present in the carrier in a mass fraction of 0.1 to 10 wt%, such as 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 5 wt%, 7 wt%, 8 wt% or 10 wt%, but not limited to the recited values, and other values not recited within this range are equally applicable.
Preferably, the active ingredient comprises any one of, or a combination of at least two of, phosphoric acid, polyphosphoric acid, magnesium phosphate, aluminum phosphate, calcium phosphate, or boron phosphate, typical but non-limiting examples of which are: combinations of phosphoric acid and magnesium phosphate, polyphosphoric acid and aluminum phosphate, calcium phosphate and boron phosphate, phosphoric acid, magnesium phosphate and aluminum phosphate, phosphoric acid, polyphosphoric acid, aluminum phosphate and calcium phosphate, and the like.
As the preferable technical proposal of the utility model, the gaseous mixture is preheated to form the gaseous state before being introduced into the fluidized bed reactor in the step (1).
The utility model discloses in, because caprolactam is solid-state at the normal atmospheric temperature, organic solvent is liquid, and the mixture is gaseous under the reaction temperature, therefore needs preheat earlier, forms gaseous mixture in advance, makes it get into fluidized bed reactor and can begin to react.
Preferably, the temperature of the ammoniation dehydration reaction in step (1) is 300 to 500 ℃, for example 300 ℃, 320 ℃, 350 ℃, 380 ℃, 400 ℃, 420 ℃, 450 ℃, 480 ℃ or 500 ℃, but not limited to the recited values, and other values not recited in the range of the values are also applicable, preferably 350 to 450 ℃.
Preferably, the pressure of the ammoniation dehydration reaction in step (1) is 0 to 3MPa, for example, 0MPa, 0.2MPa, 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa or 3MPa, but is not limited to the recited values, and other values not recited in the above range are also applicable, and preferably 0.2 to 1 MPa.
Preferably, in the ammonification dehydration reaction in the step (1), the weight hourly space velocity of caprolactam is 0.1-10 h-1E.g. 0.1h-1、0.5h-1、1h-1、2h-1、3h-1、5h-1、6h-1、8h-1Or 10h-1And the like, but not limited to the recited values, and other values not recited within the range of the recited values are also applicable, and preferably 0.5 to 5 hours-1。
The utility model discloses in, reaction temperature, pressure and airspeed are the important technological parameter that the reaction goes on, the pressure of reaction is measured with the gauge pressure, and airspeed is great with the contact time relevance, if the airspeed crosses lowly, can cause the device productivity to cross lowly, is unfavorable for the industrialization to be implemented, if the airspeed is too high, then can add catalyst surface coking, shortens the catalyst life-span.
In a preferred embodiment of the present invention, the catalyst withdrawal rate in step (2) is 0.5 to 2 wt%, for example, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, or 2 wt%, based on the total amount of the catalyst withdrawn per hour, but is not limited to the recited values, and other values not recited in the above range are also applicable.
Preferably, the catalyst of step (2) is continuously withdrawn or intermittently withdrawn.
Preferably, the composition of the oxygen-containing regeneration gas of step (2) comprises oxygen and nitrogen.
Preferably, the volume fraction of oxygen in the oxygen-containing regeneration gas in step (2) is 0.1 to 50%, for example, 0.1%, 0.5%, 2%, 5%, 10%, 15%, 20%, 30%, 40%, or 50%, etc., but not limited to the recited values, and other values not recited in the range of values are also applicable, preferably 2 to 20%.
In a preferred embodiment of the present invention, the temperature of the regeneration treatment in the step (2) is 300 to 800 ℃, for example, 300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, or 800 ℃, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the pressure of the regeneration treatment in step (2) is 0 to 1MPa, for example, 0MPa, 0.2MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.8MPa or 1MPa, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, the weight hourly space velocity of the regeneration gas in the step (2) is 0.01-10 h-1E.g. 0.01h-1、0.05h-1、0.1h-1、0.5h-1、1h-1、2h-1、3h-1、5h-1、8h-1Or 10h-1And the like, but not limited to the recited values, and other values not recited within the range of the recited values are also applicable, and preferably 0.05 to 3 hours-1。
The utility model discloses in, the regeneration process of catalyst mainly is the oxidation that utilizes oxygen, oxidizes substances such as carbon deposit and tar on catalyst surface into substances such as carbon dioxide, water and nitrogen oxide under higher temperature condition for active site in the deactivation catalyst exposes, easily contacts with the reactant, thereby realizes the regeneration of catalyst.
As a preferred technical solution of the present invention, the method comprises the steps of:
(1) introducing a gaseous mixture of caprolactam and ammonia gas or a gaseous mixture of caprolactam, ammonia gas and an organic solvent into a fluidized bed reactor, wherein the organic solvent comprises any one or a combination of at least two of methanol, ethanol, acetonitrile, toluene or xylene, the weight ratio of the caprolactam, the ammonia gas and the organic solvent is (1) (0.2-20) (0-10), an ammoniation dehydration reaction is carried out under the action of a catalyst, active components of the catalyst comprise supported phosphoric acid and/or phosphate, a carrier of the catalyst comprises alumina and/or silica, the ammoniation dehydration reaction is carried out at the temperature of 300-500 ℃, the pressure of 0-3 MPa, and the weight hourly space velocity metered by the caprolactam is 0.1-10 h-1To produce 6-aminocapronitrile;
(2) part of catalyst is continuously or intermittently extracted in the reaction process of the step (1) and enters a regenerator,the extraction rate of the catalyst is 0.5-2 wt% of the total amount of the catalyst extracted per hour, oxygen-containing regeneration gas is adopted for regeneration treatment, the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 0.1-50%, the temperature of the regeneration treatment is 300-800 ℃, the pressure is 0-1 MPa, and the weight hourly space velocity is 0.01-10 h-1And returning the regenerated catalyst to the fluidized bed reactor.
Compared with the prior art, the utility model discloses following beneficial effect has:
(1) the device of the utility model uses the fluidized bed reactor and the regenerator together, can realize the regeneration of the catalyst when preparing the 6-aminocapronitrile, avoids the problem of poor operation stability of the device caused by the inactivation of the catalyst, and has continuous stable operation time of more than 3200 h;
(2) the utility model adopts the gas phase method to prepare 6-aminocapronitrile, the contact area between the reaction raw material and the catalyst is large, the heat and mass transfer effect is good, and the synchronous regeneration of the catalyst overcomes the defects of fast attenuation of the activity of the catalyst and short service life, and is beneficial to improving the conversion rate of the raw material and the selectivity of the product, the conversion rate of caprolactam can reach more than 96.5 percent, and the selectivity of 6-aminocapronitrile can reach more than 95.4 percent;
(3) device simple structure, the cost is lower, catalyst long service life, and reaction effect is good, has good economic nature.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for preparing 6-aminocapronitrile by a gas phase method provided in example 1 of the present invention;
the method comprises the following steps of 1-a fluidized bed reactor, 2-a regenerator, 3-a riser, 4-a valve and 5-a solid feeding device.
Detailed Description
To better explain the utility model, the technical proposal of the utility model is convenient to understand, and the utility model is further explained in detail below. However, the following embodiments are only simple examples of the present invention, and do not represent or limit the scope of the present invention, which is defined by the appended claims.
The utility model provides a gas phase method preparation 6-aminocapronitrile's device is provided in the embodiment part, the device includes fluidized bed reactor 1 and regenerator 2, fluidized bed reactor 1's solid export links to each other with regenerator 2's solid entry, regenerator 2's solid export links to each other with fluidized bed reactor 1's solid entry, regenerator 2's bottom is equipped with the regeneration gas entry.
The following are typical but non-limiting examples of the present invention:
example 1:
the embodiment provides a device for preparing 6-aminocapronitrile by a gas phase method, the structural schematic diagram of the device is shown in figure 1, the device comprises a fluidized bed reactor 1 and a regenerator 2, a solid outlet of the fluidized bed reactor 1 is connected with a solid inlet of the regenerator 2, a solid outlet of the regenerator 2 is connected with a solid inlet of the fluidized bed reactor 1, and a regeneration gas inlet is arranged at the bottom of the regenerator 2.
The upper part of the fluidized bed reactor 1 is connected with a riser 3, and a solid outlet of the regenerator 2 is connected to the riser 3.
The bottom of the fluidized bed reactor 1 is provided with a gaseous mixture inlet, and the top of the riser 3 is a reaction product outlet.
And a valve 4 is arranged on a connecting pipeline between the solid outlet of the fluidized bed reactor 1 and the solid inlet of the regenerator 2.
And a solid feeding device 5 is arranged on a connecting pipeline between the solid outlet of the regenerator 2 and the solid inlet of the fluidized bed reactor 1.
Example 2:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam, ammonia gas and acetonitrile into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas to the acetonitrile is 1:4:3, and carrying out amination dehydration reaction under the catalysis of aluminum oxide loaded with aluminum phosphate, wherein the aluminum phosphate accounts for 5 wt% of the aluminum oxide, and the aluminum phosphate is prepared by adding a certain amount of aluminum phosphateThe temperature of the ammoniation dehydration reaction is 400 ℃, the pressure is 0.2MPa, and the weight hourly space velocity measured by caprolactam is 2h-1To produce 6-aminocapronitrile;
(2) continuously extracting part of the catalyst into a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 1 wt% of the total amount of the catalyst extracted per hour, and regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 5%, the temperature of the regeneration treatment is 500 ℃, the pressure is 0.2MPa, and the weight hourly space velocity is 0.5h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 98.9%, and the selectivity of 6-aminocapronitrile is 98.7%; the continuous stable running time of the device reaches 4000 h.
Example 3:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam, ammonia gas and toluene into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas to the toluene is 1:0.8:0.1, carrying out amination and dehydration reaction under the catalysis of aluminum oxide loaded with aluminum phosphate, the mass fraction of the aluminum phosphate in the aluminum oxide is 0.5 wt%, the temperature of the amination and dehydration reaction is 500 ℃, the pressure is 1MPa, and the weight hourly space velocity measured by the caprolactam is 5h-1To produce 6-aminocapronitrile;
(2) continuously extracting part of the catalyst into a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 0.5 wt% of the total amount of the catalyst extracted per hour, and regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 20%, the temperature of the regeneration treatment is 300 ℃, the pressure is 1MPa, and the weight hourly space velocity is 0.1h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 96.7%, and the selectivity of 6-aminocapronitrile is 97.2%; the continuous stable operation time of the device reaches 3500 h.
Example 4:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam, ammonia gas and ethanol into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas to the ethanol is 1:20:10, carrying out ammoniation dehydration reaction under the catalysis of silicon dioxide of calcium phosphate, the mass fraction of the calcium phosphate in the silicon dioxide is 4 wt%, the temperature of the ammoniation dehydration reaction is 300 ℃, the pressure is 3MPa, and the weight hourly space velocity measured by the caprolactam is 0.5h-1To produce 6-aminocapronitrile;
(2) continuously extracting part of catalyst to enter a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 2 wt% of the total amount of the catalyst extracted per hour, and regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 50%, the temperature of the regeneration treatment is 800 ℃, the pressure is 0MPa, and the weight hourly space velocity is 5h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 98.6%, and the selectivity of 6-aminocapronitrile is 99.2%; the continuous stable running time of the device reaches 5000 h.
Example 5:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam and ammonia gas into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas is 1:4, carrying out an ammoniation dehydration reaction under the catalysis of alumina loaded with phosphoric acid, the mass fraction of the phosphoric acid in the alumina is 7.5 wt%, the temperature of the ammoniation dehydration reaction is 350 ℃, the pressure is 0.5MPa, and the weight hourly space velocity measured by the caprolactam isIs 6h-1To produce 6-aminocapronitrile;
(2) intermittently extracting part of the catalyst into a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 1.5 wt% of the total amount of the catalyst extracted per hour, regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 2%, the temperature of the regeneration treatment is 600 ℃, the pressure is 0.8MPa, and the weight hourly space velocity is 3h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 99.1%, and the selectivity of 6-aminocapronitrile is 97.9%; the continuous stable operation time of the device reaches 4500 h.
Example 6:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam and ammonia gas into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas is 1:10, carrying out ammoniation dehydration reaction under the catalysis of alumina loaded with magnesium phosphate and calcium phosphate, the mass ratio of the magnesium phosphate to the calcium phosphate to the alumina is 0.01:0.09:1, the temperature of the ammoniation dehydration reaction is 450 ℃, the pressure is 2MPa, and the weight hourly space velocity measured by the caprolactam is 0.1h-1To produce 6-aminocapronitrile;
(2) intermittently extracting part of the catalyst into a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 1.2 wt% of the total amount of the catalyst extracted per hour, regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 10%, the temperature of the regeneration treatment is 400 ℃, the pressure is 0.4MPa, and the weight hourly space velocity is 0.05h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 99.6%, and the selectivity of 6-aminocapronitrile is 98.9%; the continuous stable operation time of the device reaches 5300 h.
Example 7:
this example provides a gas phase process for the preparation of 6-aminocapronitrile using the apparatus of example 1, comprising the steps of:
(1) introducing a gaseous mixture formed by preheating caprolactam, ammonia gas and acetonitrile into a fluidized bed reactor 1, wherein the weight ratio of the caprolactam to the ammonia gas to the acetonitrile is 1:0.2:5, carrying out ammoniation dehydration reaction under the catalysis of aluminum oxide loaded with aluminum phosphate, wherein the aluminum phosphate accounts for 2 wt% of the aluminum oxide, the ammoniation dehydration reaction is carried out at the temperature of 400 ℃, the pressure of 0.5MPa and the weight hourly space velocity measured by the caprolactam is 4h-1To produce 6-aminocapronitrile;
(2) continuously extracting part of the catalyst into a regenerator 2 in the reaction process of the step (1), wherein the extraction rate of the catalyst is 0.8 wt% of the total amount of the catalyst extracted per hour, and regenerating by using oxygen-containing regeneration gas, wherein the oxygen-containing regeneration gas comprises oxygen and nitrogen, the volume fraction of the oxygen is 30%, the temperature of the regeneration treatment is 700 ℃, the pressure is 0.6MPa, and the weight hourly space velocity is 8h-1And the regenerated catalyst is returned to the fluidized-bed reactor 1.
In this example, in the ammonification dehydration reaction, the conversion rate of caprolactam is 96.5%, and the selectivity of 6-aminocapronitrile is 95.4%; the continuous stable operation time of the device reaches 3200 h.
Comparative example 1:
this comparative example provides a process for the preparation of 6-aminocapronitrile in a gas phase process, using the apparatus of example 1, with reference to the process of example 3, except that: in the step (1), the weight ratio of caprolactam to ammonia to toluene is 1:0.15: 0.1.
In this comparative example, the caprolactam conversion and 6-aminocapronitrile selectivity were reduced by too high a weight ratio of caprolactam to ammonia in the feed, i.e., too little ammonia was added, and the caprolactam conversion was only 81.6% and the 6-aminocapronitrile selectivity was only 82.5%, and the continuous steady operation time of the apparatus was reduced to 1500 hours.
Comparative example 2:
this comparative example provides an apparatus and a process for the preparation of 6-aminocapronitrile in a gas phase process, with reference to the apparatus of example 1, with the only difference that: the apparatus does not include regenerator 2.
The process is referred to the process in example 2, with the only difference that: the operation of step (2) is not included.
In this comparative example, since the apparatus was not provided with a regenerator, the catalyst was gradually deactivated during the preparation of 6-aminocapronitrile, and the conversion of caprolactam and the selectivity of 6-aminocapronitrile were both gradually decreased as the reaction proceeded, which affected the stable operation of the apparatus, which was only 900 hours in continuous operation, resulting in a lower production efficiency of 6-aminocapronitrile.
It can be seen from the above examples and comparative examples that the apparatus of the present invention uses the fluidized bed reactor and the regenerator together, and can realize the regeneration of the catalyst while preparing 6-aminocapronitrile, avoid the problem of poor stability of the apparatus operation caused by the inactivation of the catalyst, and the continuous stable operation time of the apparatus can reach more than 3200 hours; the 6-aminocapronitrile is prepared by adopting a gas phase method, the contact area between the reaction raw material and the catalyst is large, the heat and mass transfer effects are good, the synchronous regeneration of the catalyst overcomes the defects of quick attenuation of the activity of the catalyst and short service life, the conversion rate of the raw material and the selectivity of the product are improved, the conversion rate of caprolactam can reach more than 96.5 percent, and the selectivity of the 6-aminocapronitrile can reach more than 95.4 percent; the device has the advantages of simple structure, low cost, long service life of the catalyst, good reaction effect and good economy.
The applicant states that the present invention is described in the above embodiments, but the present invention is not limited to the above detailed device, i.e. the present invention must not be implemented by relying on the above detailed device. It should be clear to those skilled in the art that any improvement of the present invention, to the addition of the equivalent replacement and auxiliary devices of the present invention, the selection of the specific mode, etc., all fall within the scope of protection and disclosure of the present invention.
Claims (6)
1. The device for preparing 6-aminocapronitrile by using the gas phase method is characterized by comprising a fluidized bed reactor and a regenerator, wherein a solid outlet of the fluidized bed reactor is connected with a solid inlet of the regenerator, a solid outlet of the regenerator is connected with a solid inlet of the fluidized bed reactor, and a regeneration gas inlet is formed in the bottom of the regenerator.
2. The apparatus for preparing 6-aminocapronitrile in a gas phase process according to claim 1, wherein a riser is connected to an upper portion of the fluidized-bed reactor.
3. The apparatus for the vapor-phase process for the preparation of 6-aminocapronitrile according to claim 2, characterized in that the solid outlet of the regenerator is connected to a riser.
4. The apparatus for the vapor-phase process for the preparation of 6-aminocapronitrile according to claim 2, characterized in that the bottom of the fluidized-bed reactor is provided with an inlet for the gaseous mixture and the top of the riser is an outlet for the reaction products.
5. The apparatus for preparing 6-aminocapronitrile in a gas phase process according to claim 1, wherein a valve is provided in a connection line between the solid outlet of the fluidized bed reactor and the solid inlet of the regenerator.
6. The apparatus for preparing 6-aminocapronitrile in a gas phase process according to claim 1, wherein a solid feeding means is provided on a connection line between the solid outlet of the regenerator and the solid inlet of the fluidized bed reactor.
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