Method and process system for continuously producing citronellal from citral

Abstract

The invention provides a method and a process system for continuously producing citronellal from citral, and the method comprises the following steps: under the catalytic action of a catalyst, introducing hydrogen into citral, and carrying out a hydrogenation reaction to prepare citronellal; wherein the hydrogen introduced in the hydrogenation reaction contains 100 to 600 ppm of activated gas; the activated gas is selected from NO or NO2. According to the method and the device for continuously preparing citronellal from citral, provided by the invention, the defect that a noble metal catalyst in an aldehyde system is easily poisoned by CO generated by aldehyde decomposition is overcome, online activation of the catalyst is realized, and cyclic application of the catalyst in the reactor is also realized.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing citronellal, and particularly relates to a method for selectively hydrogenating citral to prepare citronellal. Background Art

[0002] Citral (3,7-dimethyl-2,6-octadienal) is an important acyclic monoterpene aldehyde and also an important raw material for pharmaceuticals and fragrances. Citronellal (3,7-dimethyl-6-octenal) is similar to citral and has lemon, citronella, and rose aromas. It is mainly used in edible flavors and also as a low-grade soap perfume. Citronellal is a downstream product of citral and is an important precursor for citronellol and citronitrile. It can also be used to synthesize vitamin E and is a key intermediate for synthesizing menthol.

[0003] Citronellal can be extracted from citronella oil and lemon eucalyptus leaf oil. However, the quality of naturally prepared citronellal varies greatly due to factors such as the origin climate and extraction process. Currently, it is mainly synthesized by chemical synthesis methods in industry. In the prior art, most techniques obtain citronellal through the batch reaction of citral under the action of a catalyst. After each batch of reaction, the catalyst needs to be treated and recycled, with many auxiliary operations. Moreover, the hydrogen absorption and heat release amounts are unstable during the batch process, increasing the control difficulty of stable operation.

[0004] CN101185904A discloses a catalyst suitable for the selective liquid-phase catalytic hydrogenation of unsaturated carbonyls to form corresponding saturated carbonyl compounds or unsaturated alcohols. The catalyst is a metal component supported on a structured composite nanofiber and can be installed in a reactor. It is easier to separate from the material compared to homogeneous catalysts. However, the process for preparing this catalyst is relatively complex, and many accessories need to be set in the reaction kettle to fix the catalyst. CN108794314A discloses a method for synthesizing citronellal by hydrogenating citral. Using citral as the raw material, nickel molybdenum and palladium molybdenum are used as catalysts, and an alkali promoter and a solvent are successively added to prepare citronellal. CN102935384 discloses a new catalyst, a chiral bisphosphine ligand noble metal complex catalyst. After reacting a noble metal compound with perchlorate in an organic polar solvent, a bisphosphine ligand is added to obtain the catalyst. The preparation time of this catalyst is long, and the catalyst forms a homogeneous phase with the solvent, making it impossible to recover and recycle the catalyst. In addition, the reaction solution after the reaction needs to be washed with water before entering the distillation system for separation, increasing the complexity of separation.

[0005] CN110961154A discloses a method for preparing citronellal by hydrogenating citral, which uses rare earth catalysts, metal oxides and Pd as hydrogenation catalysts, and adds N-heterocyclic compounds as additives, which reduces the possibility of aldehyde decomposition to produce CO and inhibits the probability of catalyst poisoning. However, N-heterocyclic compounds usually have a pungent odor and a low threshold. In order to ensure the fragrance of citronellal, N-heterocyclic compounds need to be removed, which increases the complexity of post-processing.

[0006] Marco Burgener et al. conducted a detailed study on the deactivation of precious metal catalysts in aldehyde and hydrogen systems. The results showed that the aldehyde group is easily decomposed during the reaction to produce trace amounts of CO, which has a poisoning effect on Pd-based catalysts, causing the catalyst to lose activity.

[0007] As can be seen from the above, the process of hydrogenating citral to produce citronellal focuses on the research of catalysts, and the citral hydrogenation system is prone to produce trace amounts of CO due to the decomposition of aldehydes, which in turn causes the catalyst to lose activity and reduces the utilization rate of the catalyst. In order to solve the problem of catalyst deactivation in the reaction of citral to citronellal, it is necessary to perform complex treatment on the catalyst or use a variety of additives, which increases the catalyst investment cost in the process of producing citronellal from citral and also increases the difficulty of subsequent product refining and purification. SUMMARY OF THE INVENTION

[0008] In order to overcome the shortcomings of the prior art, the present invention provides a method and device for continuously preparing citronellal from citral. The catalyst can be recycled inside the reactor and equipped with online catalyst activation measures, thus overcoming the disadvantage that the noble metal catalyst in the aldehyde system is easily poisoned by CO generated by aldehyde decomposition.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a method for continuously producing citronellal from citral, wherein hydrogen is introduced into citral under the catalytic action of a catalyst to carry out a hydrogenation reaction to obtain citronellal; wherein the hydrogen introduced in the hydrogenation reaction contains 100 to 600 ppm of an activated gas; the activated gas is selected from NO or NO 2 .

[0011] The preparation method of the present invention is to continuously introduce a trace amount of NO or NO into the reactor. 2 H 2 , NO or NO 2 Reacts with CO to generate CO under the action of precious metal catalyst 2 and N 2 , achieving continuous activation of the catalyst, overcoming the disadvantage that the noble metal catalyst in the aldehyde system is easily poisoned by CO generated by the decomposition of aldehyde.​

[0012] In some specific embodiments, the hydrogen gas introduced in the hydrogenation reaction contains 200 - 500 ppm of NO.

[0013] In some specific embodiments, the hydrogenation reaction is carried out under the condition that ether or a mixture of water and ether is used as the solvent; the addition amount of the solvent is 10% - 80% of the mass of citral, preferably 40% - 60%.

[0014] In some specific embodiments, the addition amount of the catalyst is 0.5% - 5% of the mass of citral, preferably 1.5% - 3%.

[0015] In some specific embodiments, the catalyst is selected from palladium - on - activated - carbon catalyst, ruthenium - on - activated - carbon catalyst or palladium - on - molecular - sieve catalyst.

[0016] In some specific embodiments, the temperature of the hydrogenation reaction is 35 - 150 °C, preferably 50 - 90 °C; the operating pressure is 0 - 1.0 MpaG, preferably 0.2 - 0.5 MpaG.

[0017] In the second aspect of the present invention, there is provided a process system for continuously producing citronellal by using the above - mentioned method, including:

[0018] Hydrogen feed line: used to transport hydrogen gas into the reaction kettle;

[0019] Raw material feed line: used to transport citral and the solvent into the reaction kettle;

[0020] Catalyst feed line: used to transport the catalyst into the reaction kettle;

[0021] Activating gas transmission pipeline: connected to the activating gas inlet at the bottom of the reaction kettle, used to transport the activating gas into the reaction kettle;

[0022] Reaction kettle: used to provide a reaction site for the hydrogenation reaction of citral and hydrogen gas; a gas - phase outlet is provided at the top of the reaction kettle, and the gas - phase outlet is connected to distillation column I; a discharge port and an activating gas inlet are provided at the bottom of the reaction kettle, and the discharge port is connected to distillation column II;

[0023] Distillation column I: used to separate the gas phase in the reaction kettle; the liquid phase after condensation at the top of the tower is recycled as the solvent back to the reaction kettle, the gas phase at the top of the tower is compressed and then connected to the activating gas transmission pipeline and returned to the reaction kettle, and the product liquid containing light components separated is transported to distillation column II for refining treatment;

[0024] Distillation column II: used to refine the product from the discharge port of the reaction kettle and the product liquid containing light components drawn from the side line of distillation column I to obtain light components, heavy components and citronellal products.

[0025] The autoclave reactor used in the process system of the present invention is a commonly used high-pressure resistant autoclave reactor. For example, the height-to-diameter ratio is 1.2:1 to 1, and it has an elliptical head. In some specific embodiments, a filter is provided above the discharge port of the reaction kettle, and a plurality of activation gas inlets are provided around the discharge port. After the activation gas enters the bottom of the reaction kettle through the inlet, it blows the catalyst attached to the filter mesh away from the filter mesh and intercepts it in the reaction kettle to ensure the catalyst concentration in the main body of the reaction solution, and has the functions of catalyst filtration and gas dispersion; at the same time, it also enhances the mass transfer in the reaction kettle, reduces the power of the agitator in the kettle, and thus ensures the continuous recycling of the catalyst and the long-term operation of the device.

[0026] In some specific embodiments, citral and the solvent continuously enter the reaction kettle together, and the hydrogen feed adopts a common gas inlet pipe method, and the hydrogen is dispersed in the reaction kettle through stirring.

[0027] In some specific embodiments, the reaction kettle in the present invention removes heat by vaporizing the solvent in the kettle, and maintains the temperature in the reaction kettle by adjusting the liquid temperature of the condenser at the top of the first distillation column. This heat removal method greatly simplifies the complexity of the processing inside the kettle compared with the traditional type of setting internal coil pipes in the reaction kettle, and at the same time realizes the rough separation of the solvent and light components, reducing the energy consumption of separation.

[0028] In the specific process system of the present invention, the top gas phase separated by the first distillation column is condensed in the exhaust condenser, and then compressed by a compressor and returned to the reaction kettle together with the activation gas in the activation gas pipeline; the process system of the present invention realizes the online activity of the hydrogenation reaction catalyst by controlling the content of the activation gas in the activation gas pipeline, improves the problem that the noble metal catalyst in the aldehyde system is easily poisoned by CO generated by aldehyde decomposition, and improves the stable operation time of the hydrogenation reaction catalyst.

[0029] In some specific embodiments, there is also an exhaust pipeline at the outlet of the compressor for discharging the non-condensable gas in the system. An exhaust valve is provided on the pipeline, and the pressure in the reaction kettle can be indirectly adjusted by adjusting the opening of the exhaust valve.

[0030] In some specific process systems, the gas phase pipeline at the top of the reaction kettle is taken out to the first distillation column to separate the product from the solvent and at the same time remove heat from the reaction kettle.

[0031] In some specific embodiments, a nitrogen output port can be provided on the catalyst feed line for blowing the catalyst into the reaction kettle; in some more specific embodiments, the feeding method of the catalyst can be to blow the solid catalyst into the reaction kettle with hot nitrogen carrying water vapor. Specifically, a nitrogen preheater and a water tank can be provided on the catalyst feed line to realize that in the hot nitrogen entraining water vapor, the catalyst is fed by hot nitrogen carrying moisture, reducing the problem of dust flying of the solid catalyst.

[0032] Adopting the above technical solution, the following technical effects are achieved:

[0033] In the present invention, the catalyst is online activated by using hydrogen containing NO, effectively maintaining the long-term operation stability of the catalyst, and the stable operation time of the catalyst reaches 3600 hr; at the same time, as an oxidizing gas, NO can react with CO generated by aldehyde substances under the action of noble metals to generate CO 2 and N 2 The product is relatively environmentally friendly and does not produce excess substances.

[0034] The substances generated by the online activation of the catalyst form a minimum azeotrope with the reaction light components, reducing the separation difficulty, improving the product purity, and reducing the content of light components in the product.

[0035] The process system of the present invention uses the method of solvent evaporation to remove heat, making the most of the latent heat of the solvent and improving the heat removal efficiency; it also realizes the recycling of the solvent through distillation, reducing the separation energy consumption of the solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a specific embodiment of the citral preparation citronellal process system provided by the present invention;

[0037] Among them, 1. Nitrogen preheater, 2. Water tank, 3. Reaction kettle, 4. Distillation column I, 5. Distillation column II, 6. Exhaust condenser, 7. Compressor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The following details the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0039] In the following examples, the products adopt the following analytical instruments and methods: The gas chromatograph is Agilent 7890, with a capillary column (DB-5, 30 m × 0.25 mm × 0.25 μm), an inlet temperature of 300 °C, and a split ratio of 50:1. The carrier gas flow rate is 50 ml / min. The temperature programming: hold at 120 °C for 15 min, increase to 250 °C at a rate of 10 °C / min, hold for 10 min, and the detector temperature is 280 °C. This instrument is used to characterize the conversion rate of citral and the selectivity of citronellal.

[0040] In the following examples, a batch reactor is used, and the total volume of the batch reactor is 0.7 m 3 , the diameter is 800 mm, the height is 1000 mm, the diameter of the activation gas inlet at the bottom of the kettle is 6 mm, and the wall thickness of the pipe is 1.8 mm. Figure 1 As shown in, specifically, the process system of the present invention includes: a reaction kettle 3, a hydrogen feed line, a raw material feed line, a catalyst feed line, an activation gas transmission pipeline, a distillation column I 4, and a distillation column II 5; a gas phase outlet is provided at the top of the reaction kettle 3, and the gas phase outlet is connected to the distillation column I 4. An outlet and an activation gas inlet are provided at the bottom of the reaction kettle 3, and the outlet is connected to the distillation column II 5. A hydrogen feed line for transporting hydrogen, a raw material feed line for transporting citral and a solvent, a catalyst feed line for transporting a catalyst, and an activation gas transmission pipeline for transporting activation gas into the kettle are also connected to the side wall of the reaction kettle 3.

[0041] The distillation column I 4 is used to separate the gas phase in the reaction kettle 3; the liquid phase after condensation at the top of the tower is recycled to the reaction kettle 3 as a solvent. After the gas phase at the top of the tower is condensed in the exhaust condenser 6 and then compressed by a compressor 7, it is connected to the activation gas transmission pipeline and then recycled to the reaction kettle 3. The product liquid containing light components separated by the distillation column I 4 is transported to the distillation column II 5 for refining treatment. The distillation column II 5 is used to refine the product from the outlet of the reaction kettle 3 and the product liquid containing light components taken from the side line of the distillation column I 4, and finally obtain light components, heavy components, and citronellal products.

[0042] A nitrogen output port is also provided on the catalyst feed line to blow the catalyst in the catalyst feed line into the reaction kettle. A filter is provided above the outlet of the reaction kettle 3 to intercept the catalyst in the product in the reaction kettle through the filter screen in the filter.

[0043] Example 1

[0044] Adopt as Figure 1 shown in the process system. Nitrogen is preheated to 60 °C by a nitrogen preheater 1 and then enters the water jacket 2 from the bottom. The feed rate of nitrogen is 20 Nm 3 / hr. The outlet of the water jacket 2 is hot nitrogen with entrained water, and the water content in the nitrogen is 1.5%.

[0045] Ether and citral are continuously fed into the reaction kettle 3 from the raw material feed line at a ratio of 2:3, and the total feed rate is 50 kg / hr. The reaction pressure in the reaction kettle 3 is controlled at 0.4 MPaG through the feed regulating valve on the hydrogen feed line and the exhaust regulating valve on the gas phase line of the rectifying column 4Ⅰ. At the same time, the reaction temperature in the reaction kettle 3 is 80 °C. The activated carbon supported palladium catalyst is added to the reaction kettle 3 through the catalyst feed line, and the catalyst addition amount is 1% of the mass of citral.

[0046] During the reaction process, hydrogen with activated gas NO continuously returns from the activated gas transmission line to the reaction kettle 3, and the controlled feeding rate is 10 Nm 3 / hr, where the NO content is 200 ppm. The bottom of the reaction kettle 3 continuously discharges materials, and the continuous extraction rate is 50 kg / hr.

[0047] The reaction lasts for 720 hr. Samples are taken every 6 hr at the lower liquid line of the reaction kettle 3 and the product sampling outlet of the rectifying column Ⅱ5 to analyze the contents of citronellal and citral. During the 720 hr of the reaction, no decrease in the conversion rate and selectivity of citral is found.

[0048] After detection, the conversion rate of citral is 99%, the selectivity of citronellal is 95%, and the product purity is 99%.

[0049] Maintain these operating conditions and continue to run for 3600 hr. During this period, samples are taken every 24 hr at the lower liquid line of the reactor and the product sampling outlet of the rectifying column Ⅱ to analyze the contents of citronellal and citral, and calculate the conversion rate and selectivity of citral. No obvious decrease is found. The conversion rate of citral is ≥98%, the selectivity of citronellal is ≥93%, and the purity is ≥99%. The results show that this method can achieve long-term operation of the catalyst.

[0050] Example 2

[0051] Example 2 uses the same equipment, reaction pressure, reaction temperature, and catalyst concentration as Example 1. During the reaction process, hydrogen with activated gas NO continuously passes from the activated gas transmission line into the reaction kettle, and the controlled feeding rate is 10 Nm 3 / hr, the NO content is 400 ppm, the bottom of the reaction kettle continuously discharges materials, and the continuous extraction rate is 50 kg / hr.

[0052] The reaction lasts for 720 hr. Samples are taken every 6 hr at the lower liquid line of the reactor and the product sampling outlet of the rectifying column Ⅱ to analyze the contents of citronellal and citral. During the 720 hr of the reaction, no decrease in the conversion rate and selectivity of citral is found.

[0053] After detection, the conversion rate of citral is 99%, the selectivity of citronellal is 95%, and the purity is 99.4%.

[0054] Maintain this operating condition and continuously run for 3600 hr. During this period, samples are taken every 24 hr at the bottom liquid pipeline of the reactor and the product outlet of rectification column II to analyze the contents of citronellal and citral, calculate the conversion rate and selectivity of citral, and no obvious decrease is found. The conversion rate of citral is ≥98%, the selectivity of citronellal is ≥93%, and the purity is ≥99%. The results show that this method can achieve long-term operation of the catalyst.

[0055] Example 3

[0056] In Example 3, the same equipment, reaction pressure, reaction temperature, and catalyst concentration as in Example 1 are used. During the reaction process, activated gas NO 2 -containing hydrogen gas continuously flows from the activated gas pipeline into the reaction kettle, and the feeding rate is controlled at 10 Nm 3 / hr, the content of NO 2 is 400 ppm, and continuous discharging is carried out at the bottom of the reaction kettle, and the continuous discharging amount is 50 kg / hr.

[0057] The reaction lasts for 720 hr. Samples are taken every 6 hr at the bottom liquid pipeline of the reactor and the product outlet of rectification column II to analyze the contents of citronellal and citral. No decrease in the conversion rate and selectivity of citral is found within 720 hr of the reaction.

[0058] After detection, the conversion rate of citral is 99%, the selectivity of citronellal is 95%, and the purity is 99.3%.

[0059] Maintain this operating condition and continuously run for 3600 hr. During this period, samples are taken every 24 hr at the bottom liquid pipeline of the reactor and the product outlet of rectification column II to analyze the contents of citronellal and citral, calculate the conversion rate and selectivity of citral, and no obvious decrease is found. The conversion rate of citral is ≥98%, the selectivity of citronellal is ≥93%, and the purity is ≥99%. The results show that this method can achieve long-term operation of the catalyst.

[0060] Comparative Example 1

[0061] This comparative example uses the same equipment, reaction pressure, reaction temperature, and catalyst concentration as in Example 1. The difference is that no activated gas NO or NO 2 is introduced into the activated gas pipeline; the feeding rate of hydrogen gas into the reaction kettle is 10 Nm 3 / hr, continuous discharging is carried out at the bottom of the reaction kettle, and the continuous discharging amount is 50 kg / hr.

[0062] The reaction lasts for 720 hr. Samples are taken every 6 hr at the bottom liquid pipeline of the reactor and the product outlet of rectification column II to analyze the contents of citronellal and citral. It is found that the conversion rate starts to decrease at 60 hr, and until 720 hr of the reaction, the conversion rate of citral is 40%, the selectivity is 90%, and the product purity is 85%.

[0063] Comparative Example 2

[0064] Comparative Example 2 used the same equipment, reaction pressure, reaction temperature, and catalyst concentration as Example 1. The difference was that the activation gas NO was introduced into the reaction kettle through the hydrogen feed line, rather than through the activation gas delivery pipeline at the bottom of the reaction kettle.

[0065] The reaction was carried out for 720 hr. Samples were taken every 6 hr at the bottom liquid pipeline of the reactor and the product sampling outlet of rectification column II to analyze the contents of citronellal and citral. It was found that the conversion rate began to decrease since 30 hr, and until 720 hr of the reaction, the conversion rate of citral was 50%, the selectivity was 85%, and the product purity was 88%.

[0066] Comparative Example 3

[0067] This comparative example used the same equipment, reaction pressure, reaction temperature, and catalyst concentration as Example 1. During the reaction process, hydrogen with activation gas NO was continuously introduced into the reaction kettle through the activation gas delivery pipeline, and the controlled introduction speed was 10 Nm 3 / hr, the NO content was 1000 ppm, and continuous discharging was carried out at the bottom of the reaction kettle, with a continuous discharge amount of 50 kg / hr.

[0068] The reaction was carried out for 720 hr. Samples were taken every 6 hr at the bottom liquid pipeline of the reactor and the product sampling outlet of rectification column II to analyze the contents of citronellal and citral.

[0069] Since 240 hr, the conversion rate of citral began to decrease. Until 720 hr of the reaction, the conversion rate of citral decreased to 85%, the selectivity of citronellal was 90%, and the product purity was 99%.

[0070] Comparative Example 4

[0071] This comparative example used the same equipment, reaction pressure, reaction temperature, and catalyst concentration as Example 1. During the reaction process, hydrogen with activation gas NO was continuously introduced into the reaction kettle through the activation gas delivery pipeline, and the controlled introduction speed was 10 Nm 3 / hr, the NO content was 50 ppm, and continuous discharging was carried out at the bottom of the reaction kettle, with a continuous discharge amount of 50 kg / hr.

[0072] The reaction was carried out for 720 hr. Samples were taken every 6 hr at the bottom liquid pipeline of the reactor and the product sampling outlet of rectification column II to analyze the contents of citronellal and citral.

[0073] Since 200 hr, the conversion rate of citral had a decreasing trend. After detection, at 720 hr, the conversion rate of citral decreased to 85%, the selectivity of citronellal was 93%, and the product purity was 98.5%.

Claims

1. A method for continuously producing citronellal from citral, characterized in that: Under the catalytic action of a catalyst, hydrogen is introduced into citral to carry out a hydrogenation reaction to obtain citronellal; The hydrogen introduced in the hydrogenation reaction contains 100 to 600 ppm of activated gas; the activated gas is selected from NO or NO2.

2. The method according to claim 1, characterized in that The hydrogen introduced into the hydrogenation reaction contains 200 to 500 ppm of NO or NO2.

3. The method according to claim 1 or 2, characterized in that: The hydrogenation reaction is carried out under the condition that diethyl ether or a mixture of water and diethyl ether is used as a solvent; The added amount of the solvent is 10% to 80% of the mass of citral, preferably 40% to 60%.

4. The method according to any one of claims 1 to 3, characterized in that The catalyst addition amount is 0.5-5% of the mass of citral, preferably 1.5-3%.

5. The method according to claim 4, characterized in that The catalyst is selected from an activated carbon-supported palladium catalyst, an activated carbon-supported ruthenium catalyst or a molecular sieve-supported palladium catalyst.

6. The method according to any one of claims 1 to 5, characterized in that: The temperature of the hydrogenation reaction is 35 to 150°C, preferably 50 to 90°C; The operating pressure is 0-1.0 MPaG, preferably 0.2-0.5 MPaG.

7. A process system for continuously producing citronellal using the method of any one of claims 1 to 6, characterized in that: include: Hydrogen feed line: used to transport hydrogen into the reactor; Raw material feeding line: used to transport citral and solvent into the reactor; Catalyst feeding line: used to transport catalyst into the reactor; Activation gas delivery pipeline: connected to the activation gas inlet at the bottom of the reactor, used to deliver activation gas to the reactor; Reactor: used to provide a reaction place for the hydrogenation reaction of citral and hydrogen; the top of the reactor is provided with a gas phase outlet, the gas phase outlet is connected to the distillation tower I, the bottom of the reactor is provided with a discharge port and an activated gas inlet, the discharge port is connected to the distillation tower II; The distillation tower I is used to separate the gas phase in the reactor; the liquid phase condensed at the top of the tower is reused in the reactor as a solvent, the gas phase at the top of the tower is compressed and connected to the activated gas delivery pipeline and then returned to the reactor, and the separated product liquid containing light components is delivered to the distillation tower II for refining treatment; The distillation tower II is used to purify the product from the discharge port of the reactor and the product liquid containing light components taken out from the side line of the distillation tower I to obtain light components, heavy components and citronellal products.

8. The process system according to claim 7, characterized in that: The gas phase at the top of the distillation tower I is compressed by a compressor and then returned to the reactor through the activated gas delivery pipeline.

9. The process system according to claim 8, characterized in that: The catalyst feed line is also provided with a nitrogen outlet for blowing the catalyst in the catalyst feed line into the reactor.

10. The process system according to claim 9, characterized in that: A filter is arranged above the discharge port of the reactor so that the catalyst in the product can be intercepted in the reactor through the filter screen in the filter.

Images