Circulation reaction device and reaction method using same

Abstract

The invention relates to the field of gas-liquid reaction, and discloses a circulation reaction device and a reaction method using the circulation reaction device. The circulation device comprises at least one stage of circulation reactor, the circulation reactor comprises a cylinder body and a guide cylinder arranged in the cylinder body, and an annular space is formed between the cylinder body and the guide cylinder; the loop reactor is provided with a liquid-phase material inlet, a gas-phase material inlet and a gas distributor, and a gas-phase material enters the guide cylinder through the gas distributor via the gas-phase material inlet. Gas-phase materials are sprayed into the guide cylinder to form air lift, liquid is pushed to circularly flow along the guide cylinder, meanwhile, liquid-phase series feeding and gas-phase parallel feeding of all stages of reactors are achieved, it is effectively guaranteed that the materials in all stages of reactors react under the optimal process condition, the gas-liquid contact effect and the mass transfer effect are improved, and the material conversion efficiency is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of gas-liquid reactions, and specifically to a circulating reaction apparatus and a reaction method using the circulating reaction apparatus. Background Technology

[0002] Dimethyl oxalate is an important organic chemical raw material. Using dimethyl oxalate as a platform compound, many high-value chemical products can be produced, such as ethylene glycol, glycolic acid (methyl ester), polyglycolic acid, glyoxylic acid (methyl ester), dimethyl carbonate, oxamide, etc.

[0003] Currently, the large-scale industrial production of ethylene glycol via hydrogenation of dimethyl oxalate has been achieved. The technology of selectively hydrogenating dimethyl oxalate to methyl glycolate, followed by hydrolysis to produce glycolic acid, and then synthesizing the fully degradable biomaterial polyglycolic acid, is under industrial promotion and application. The decarbonylation of dimethyl oxalate to dimethyl carbonate has become a method with great industrial potential. Other technologies are also hot research topics and attract significant attention from enterprises. Therefore, further improving and enhancing dimethyl oxalate synthesis technology, reducing its production cost, and promoting the application of downstream dimethyl oxalate products are of great significance.

[0004] Industrially, the technical route for large-scale production of dimethyl oxalate uses syngas as a raw material, synthesizing dimethyl oxalate through a catalytic coupling reaction of carbon monoxide and methyl nitrite, generating nitric oxide. The nitric oxide then undergoes an oxidative esterification reaction with methanol and oxygen to produce methyl nitrite. In this technical route, nitric oxide and methyl nitrite (CH3ONO) are recycled within the system. The main reaction equations are as follows:

[0005] Coupling reaction: 2CO + 2CH3ONO → (COOCH3)2 + 2NO

[0006] Oxidative esterification reaction (regeneration reaction): 2NO + 2CH3OH + 1 / 2O2 → 2CH3ONO + H2O

[0007] During the oxidative esterification reaction, while the main reaction produces methyl nitrite, side reactions also occur, producing substances such as nitric acid. The generation of byproduct nitric acid leads to nitrogen oxide losses in the oxidative esterification and coupling cycle gas systems, requiring nitrogen oxide replenishment. This not only increases the material supply cost of the coupling system but also raises equipment investment and operating costs. Furthermore, it increases the material and energy consumption of the subsequent nitric acid treatment system. Therefore, effectively utilizing byproduct nitric acid is one of the key technologies for reducing the production cost of dimethyl oxalate.

[0008] Currently, methods for treating nitric acid, a byproduct of the syngas-to-dimethyl oxalate (DME) process, include catalytic reduction and non-catalytic reduction technologies. While catalytic reduction offers a relatively high nitric acid conversion rate, this rate decreases as catalyst activity declines, necessitating periodic catalyst replacement and increasing production costs. Existing non-catalytic nitric acid treatment systems typically employ conventional tower or batch reactors. For example, patent application ZL202311657970.4 proposes a deep nitric acid reaction and methanol recovery system and method using a tower reactor, which suffers from drawbacks such as large reactor size and long liquid-phase residence time. Patent application ZL202011573823.5 proposes a self-priming reactor and a method for preparing methyl nitrite, using a mechanically stirred reactor, which suffers from drawbacks such as high requirements for equipment sealing, high energy consumption, and low nitric acid conversion rate. Summary of the Invention

[0009] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a circulating reaction device and a reaction method using the circulating reaction device, which can effectively improve the material conversion efficiency, shorten the reaction time, and reduce the size of the equipment by increasing the circulation driving force to achieve full gas-liquid contact.

[0010] To achieve the above objectives, a first aspect of the present invention provides a circulating reaction apparatus, the apparatus comprising at least one circulating reactor, the circulating reactor comprising a cylindrical body and a guide tube disposed inside the cylindrical body, wherein an annular gap is formed between the cylindrical body and the guide tube, the circulating reactor being provided with a liquid material inlet, a gaseous material inlet and a gas distributor, the gaseous material entering the guide tube through the gaseous material inlet and the gas distributor.

[0011] Preferably, the ratio D of the diameter of the guide tube to the diameter of the circulating reactor is 0.3-0.9, and more preferably 0.4-0.8.

[0012] Preferably, the height-to-diameter ratio E of the guide tube is 4-20, more preferably 4-15.

[0013] Preferably, the ratio F of the gap height from the lower edge of the guide tube to the bottom of the circulating reactor to the diameter of the circulating reactor is 0.1-0.5, and more preferably 0.2-0.4.

[0014] Preferably, the circulating reactor comprises 1-6 stages, preferably 2-4 stages, of circulating reactors connected in series, wherein the liquid phase material outlet of the previous stage is connected to the liquid phase material inlet of the next stage.

[0015] A second aspect of the present invention provides a reaction method using the circulating reaction apparatus described in the first aspect, the method comprising:

[0016] In the circulating reactor, gaseous material enters the guide tube through the gas inlet via the gas distributor and reacts with liquid material fed through the liquid inlet.

[0017] Preferably, in a circulating reactor containing multiple circulating reactors, the reaction temperature of the later circulating reactor is not lower than the reaction temperature of the earlier circulating reactor.

[0018] Preferably, in a circulating reactor containing multiple circulating reactors, the liquid phase residence time in the later circulating reactor is not less than the liquid phase residence time in the earlier circulating reactor.

[0019] Compared with the prior art, the present invention has the following beneficial effects through the above technical solution:

[0020] (1) This invention designs a gas-phase material to be sprayed into the guide tube inside the reactor to form a gas lift, which drives the liquid to circulate along the guide tube, thereby significantly increasing the specific surface area and mass transfer coefficient of gas-liquid mass transfer, greatly improving the gas-liquid contact effect and mass transfer effect, thus significantly improving the conversion efficiency of the material, shortening the reaction time, and reducing the size of the reactor.

[0021] (2) The circulating reaction device provided by the present invention has no moving parts, is easy to seal and operate, and can create a high phase interface and mass transfer efficiency with low energy consumption.

[0022] (3) By adopting a multi-stage series design of circulating reactors, and feeding the liquid phase in series and the gas phase in parallel in each stage of the reactors, the present invention effectively ensures that the materials in each stage of the reactors react under the best process conditions, thereby ensuring a high conversion rate of the materials. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the circulating reactor of the present invention;

[0024] Figure 2 This is a schematic diagram of the circulating reaction device of the present invention, which includes a two-stage circulating reactor.

[0025] Explanation of reference numerals in the attached figures

[0026] 1. Cylinder body, 2. Flow guide tube, 3. Liquid material inlet, 4. Gas material inlet, 5. Gas distributor, 6. Liquid material outlet, 7. Gas material outlet, I. First-stage circulating reactor, II. Second-stage circulating reactor, 13. First liquid material, 14. First gas material stream, 16. Liquid product of the first circulating reactor, 17. Gas product of the first circulating reactor, 24. Second gas material stream, 26. Liquid product of the second circulating reactor, 27. Gas product of the second circulating reactor. Detailed Implementation

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] In this invention, unless otherwise specified, "first" and "second" do not limit the various materials, components, or steps, but are only used for distinction. For example, "first" and "second" in "first gaseous material" and "second gaseous material" simply indicate that they are not the same gaseous material. A first aspect of this invention provides a circulating reaction apparatus, such as... Figure 1 As shown, it includes at least one circulating reactor. The circulating reactor includes a cylinder 1 and a guide tube 2 disposed inside the cylinder. An annular gap is formed between the cylinder and the guide tube. The circulating reactor is provided with a liquid material inlet 3, a gas material inlet 4, a gas distributor 5, a liquid material outlet 6, and a gas material outlet 7.

[0029] In this invention, gaseous material enters the guide tube through the gas distributor via the gas inlet, and liquid material flows into the guide tube through the gap between the gas distributor and the guide tube after being introduced through the liquid inlet.

[0030] In this invention, preferably, the outlet position of the liquid phase material in each circulating reactor is independently higher than the inlet position of the liquid phase material.

[0031] In this invention, preferably, the inlet position of the liquid phase material in each circulating reactor is independently lower than the lower edge of the guide tube.

[0032] In this invention, preferably, the gaseous material outlet of each circulating reactor is independently located at the top of each circulating reactor.

[0033] In this invention, preferably, the gaseous material inlet of each circulating reactor is independently located at the bottom of each circulating reactor.

[0034] In this invention, preferably, the central axis of the guide tube coincides with the central axis of the circulating reactor, and the diameter of both the guide tube and the circulating reactor is the diameter of a circular cross-section.

[0035] According to the circulating reactor device provided by the present invention, preferably, the ratio D of the diameter of the guide tube to the diameter of the circulating reactor is 0.3-0.9, more preferably 0.4-0.8. This preferred embodiment is more advantageous in ensuring sufficient gas-liquid contact while effectively suppressing bubble coalescence, resulting in a more uniform gas-liquid distribution within the reactor.

[0036] Preferably, the height-to-diameter ratio E of the guide tube is 4-20, more preferably 4-15. This preferred embodiment is more conducive to ensuring sufficient gas-liquid mixing and improving gas-liquid contact effect, significantly increasing the gas-liquid mass transfer specific surface area and mass transfer coefficient, and improving the material conversion efficiency.

[0037] Preferably, the ratio F of the gap height from the lower edge of the guide tube to the bottom of the circulating reactor to the diameter of the circulating reactor is 0.1-0.5, more preferably 0.2-0.4. This preferred embodiment is more conducive to reducing the flow resistance when the gas and liquid turn inside and outside the guide tube, and ensuring the gas-liquid circulation speed.

[0038] In this invention, unless otherwise specified, "first stage" and "second stage" refer to two adjacent circulating reactors. Along the direction of liquid material flow, the one that comes first is called "first stage" and the one that comes later is called "second stage".

[0039] According to a preferred embodiment of the present invention, the D value of the subsequent circulating reactor is greater than or equal to the D value of the preceding circulating reactor.

[0040] According to a preferred embodiment of the present invention, the E value of the subsequent circulating reactor is greater than or equal to the E value of the preceding circulating reactor.

[0041] According to a preferred embodiment of the present invention, the F value of the subsequent circulating reactor is greater than or equal to the F value of the preceding circulating reactor.

[0042] In this invention, by controlling the range of D, E, and F values ​​in the subsequent circulating reactor and the preceding circulating reactor, it is possible to effectively ensure sufficient mixing of gas and liquid in the reactor and significantly improve the gas-liquid mass transfer area and mass transfer coefficient, so that the liquid phase material reacts more fully with the gas phase material, which helps to improve the overall performance of the reaction.

[0043] According to the present invention, preferably, the equivalent diameter of the gas distributor is not greater than 0.8 times the diameter of the guide tube, and more preferably 0.6-0.8 times.

[0044] In this invention, there is no particular limitation on the type of gas distributor, as long as it can achieve the function of uniformly distributing the introduced gaseous material across the entire cross-section of the guide tube. Preferably, it can be selected from either a dendritic distributor or an annular distributor.

[0045] In this invention, preferably, the gas distributor is located at the bottom of the circulating reactor.

[0046] More preferably, the plane of the nozzle of the gas distributor is not lower than the lower edge of the bottom of the guide tube. This embodiment can further promote the circulation of liquid material along the guide tube and promote the injection of gas material into the guide tube to form a gas lift. If the plane of the nozzle of the gas distributor is lower than the lower edge of the bottom of the guide tube, the gas ejected by the gas distributor will hinder the liquid material descending between the guide tube and the reactor body from smoothly entering the circulation tube, and may even promote the liquid material to form a local circulation, resulting in different residence times of the liquid material, thereby affecting the reaction performance.

[0047] According to a preferred embodiment of the present invention, the circulating reactor includes 1-6 stages of circulating reactors connected in series, wherein the liquid phase material outlet of the preceding stage is connected to the liquid phase material inlet of the following stage.

[0048] More preferably, the circulating reaction device comprises 2-4 stages of circulating reactors connected in series.

[0049] In this invention, the design of a multi-stage circulating reactor is more conducive to improving the conversion rate of raw materials throughout the process. After the gaseous material and the liquid material react in the first-stage reactor, the liquid material enters the second-stage circulating reactor and reacts with the gaseous material again. After the reaction is completed, the liquid material is discharged through the liquid material outlet of the last-stage circulating reactor.

[0050] According to the circulating reaction apparatus provided by the present invention, after the gaseous product is discharged from the gaseous material outlet, it can be cooled and separated into gas and liquid phases and then fed back into the reaction as a gaseous material.

[0051] In this invention, the methods for cooling and gas-liquid separation of the gaseous products are conventional techniques in the field and are not subject to special requirements.

[0052] In this invention, the circulating reactor device employs a multi-stage series design, with each stage of the reactor receiving liquid-phase feed in series and gas-phase feed in parallel. For example, liquid-phase materials pass sequentially through the series-connected circulating reactors, while gas-phase materials are fed into each stage of the circulating reactors in parallel.

[0053] In this invention, the specific manner in which the liquid phase material outlet of the preceding stage is connected to the liquid phase material inlet of the following stage is not limited, as long as it can serve the purpose of transporting liquid phase material.

[0054] The circulating reaction apparatus provided by this invention is suitable for contact reactions of various gas-liquid phase materials, and is particularly suitable for the reduction of nitric acid to prepare methyl nitrite. In this embodiment, the liquid phase material is a liquid phase material containing nitric acid and methanol, and the gas phase material is a gas phase material containing nitric oxide.

[0055] In a preferred embodiment, the liquid material inlet of the first-stage circulating reactor is connected to a liquid material supply unit containing nitric acid and methanol, for introducing liquid material containing nitric acid and methanol into the first-stage circulating reactor.

[0056] In a preferred embodiment, the gaseous material inlet of each stage of the circulating reactor is connected to a gaseous material supply unit containing nitric oxide, for introducing gaseous material containing nitric oxide into each stage of the circulating reactor.

[0057] In this invention, there are no particular limitations on the specific equipment of the supply unit for the liquid phase material and the gas phase material.

[0058] The specific compositions of the liquid phase material and the gaseous phase material are as described in the following method and will not be repeated here.

[0059] A second aspect of the present invention provides a reaction method using the circulating reaction apparatus described in the first aspect, the method comprising:

[0060] In the circulating reactor, gaseous material enters the guide tube through the gas inlet via the gas distributor and reacts with liquid material fed through the liquid inlet.

[0061] The circulating reaction apparatus provided by this invention is suitable for contact reactions of various gas-liquid phase materials, and is particularly suitable for the reduction of nitric acid to prepare methyl nitrite. In this embodiment, the liquid phase material is a liquid phase material containing nitric acid and methanol, and the gas phase material is a gas phase material containing nitric oxide.

[0062] In this invention, the circulating reaction device has a wide range of applications in the preparation of methyl nitrite by reducing nitric acid, and there are no particular limitations on the specific proportions of each component in the liquid phase material and the gas phase material.

[0063] According to a preferred embodiment of the present invention, the gaseous material is a gaseous material containing nitric oxide, and preferably, the volume concentration of nitric oxide in the gaseous material containing nitric oxide is 10-100%.

[0064] In this invention, preferably, in the gaseous material containing nitric oxide, the volume concentration of nitric oxide is 15-80%, the volume concentration of carbon monoxide is 0-30%, and the inert gas is preferably nitrogen with a volume concentration of 20-80%.

[0065] The present invention does not specifically limit the type of inert gas, as long as it can play a role in adjusting the gas concentration, including but not limited to nitrogen, argon, and helium, with nitrogen being preferred.

[0066] According to a preferred embodiment of the present invention, the liquid phase material is a liquid phase material containing nitric acid and methanol.

[0067] According to a preferred embodiment of the present invention, in the liquid phase material containing nitric acid and methanol, the mass concentration of methanol is 50-90%, more preferably 60-90%.

[0068] According to a preferred embodiment of the present invention, in the liquid phase material containing nitric acid and methanol, the mass concentration of nitric acid is 0.1-10%, more preferably 0.5-10%.

[0069] According to a preferred embodiment of the present invention, the water mass concentration in the liquid phase material containing nitric acid and methanol is 0-30%.

[0070] In this invention, preferably, the reaction conditions include: the reaction temperatures in the circulating reactors are each independently 40-120°C, preferably 60-100°C.

[0071] According to a preferred embodiment of the invention, the reaction temperature in the subsequent circulating reactor is not lower than the reaction temperature in the preceding circulating reactor. More preferably, the reaction temperature difference between adjacent reactor stages is not higher than 20°C.

[0072] In this invention, by using the reaction temperatures of each stage of the circulating reactor within the aforementioned defined range, the temperature of each stage of the circulating reactor can be controlled, which can effectively improve the nitric acid conversion rate and shorten the reaction time.

[0073] According to a preferred embodiment of the present invention, the volume ratio of the gas phase material inlet flow rate to the liquid phase material inlet flow rate is 200-900, preferably 200-800. This preferred embodiment is more conducive to the full conduct of the gas-liquid reaction. In the present invention, the gas phase material inlet flow rate refers to the gas phase material inlet flow rate of each stage of the circulating reactor, and the liquid phase material inlet flow rate refers to the inlet flow rate of the first stage of the circulating reactor.

[0074] According to a preferred embodiment of the present invention, the residence time of the liquid phase material is 0.5-6h, preferably 1-6h.

[0075] Preferably, the liquid phase residence time in the subsequent circulating reactor is not less than the liquid phase residence time in the preceding circulating reactor.

[0076] The residence time of the liquid phase can be controlled by adjusting the flow rate of the liquid phase material.

[0077] In this invention, as the reaction proceeds, the concentration of the liquid phase material gradually decreases. The above-described implementation method helps to increase the reaction probability between the gas phase material and the low-concentration liquid phase material, thereby further improving the nitric acid conversion rate.

[0078] The following combination Figure 1 The reaction method of the circulating reactor of the present invention will be described in detail below:

[0079] Liquid materials containing nitric acid and methanol are introduced into the circulating reactor body 1 via a liquid pump. Gaseous materials containing nitric oxide are transported to a gas distributor 5 via a gas compressor. After distribution by the gas distributor 5, the gas is sprayed into the circulating reactor guide tube 2, creating a gas lift that pushes the reacted liquid materials in the guide tube 2 upwards. The liquid materials then flow downwards through the gap between the guide tube 2 and the body 1, circulating regularly along the guide tube. This ensures sufficient contact between the gas and liquid materials, allowing the reaction to occur under good mixing and reaction conditions. The reacted liquid materials are exited through the liquid material outlet 6, and the reacted gaseous products are exited through the gaseous material outlet 7. After cooling and gas-liquid separation, the resulting gaseous product is recycled back into the system.

[0080] The following combination Figure 2 The reaction method of the circulating reaction apparatus including a two-stage circulating reactor of the present invention will be described in detail below:

[0081] According to a specific embodiment of the present invention, the reaction method of the circulating reactor device including two-stage circulating reactors includes: introducing a first liquid phase material 13 and a first gaseous phase material 14 into a first-stage circulating reactor I, mixing and contacting them thoroughly, and reacting under certain process conditions to generate products; the gaseous product 17 from the first circulating reactor is discharged from the top of the first-stage circulating reactor I; the liquid product 16 from the first circulating reactor enters a second-stage circulating reactor II, mixing and contacting it thoroughly with a second gaseous phase material 24, and reacting under certain process conditions to generate products; the reacted gaseous product 27 from the second circulating reactor II is discharged from the top of the second-stage circulating reactor II; and the reacted liquid product 26 from the second circulating reactor is introduced into a subsequent recovery system. The gaseous products discharged from the top of each reactor are recycled back to the system after cooling and gas-liquid separation.

[0082] The present invention will be further described in detail below with reference to specific embodiments.

[0083] The method for calculating the nitric acid conversion rate in the example is: Nitric acid conversion rate = [1 - outlet liquid flow rate × outlet nitric acid concentration / (inlet liquid flow rate × inlet nitric acid concentration)] × 100%.

[0084] Example 1

[0085] The nitric acid conversion reactor is a single-unit circulating reactor. The ratio of the diameter of the guide tube to the reactor diameter is 0.6, the ratio of the guide tube height to its diameter is 8, and the ratio of the gap height from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.2. The gas distributor is a dendritic distributor, and its equivalent diameter is 0.7 times the diameter of the guide tube. The reaction temperature is 90℃, the gas-liquid volume ratio is 600, and the liquid phase residence time is 6 hours.

[0086] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 5%, methanol 90%, and water 5%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 60% and N2 40%.

[0087] Using the above technical solution, the conversion rate of nitric acid is 99.18%.

[0088] Example 2

[0089] The nitric acid conversion reactor is a single-unit circulating reactor. The ratio of the diameter of the guide tube to the reactor diameter is 0.8, the ratio of the guide tube height to its diameter is 10, and the ratio of the gap height from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.25. The gas distributor is an annular distributor with an equivalent diameter 0.6 times that of the guide tube diameter. The reaction temperature is 80℃, the gas-liquid volume ratio is 500, and the liquid phase residence time is 4 hours.

[0090] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 5.4%, methanol 74.6%, and water 20%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 40%, CO 30%, and N2 30%.

[0091] Using the above technical solution, the conversion rate of nitric acid is 98.68%.

[0092] Example 3

[0093] The same nitric acid conversion reactor and reaction conditions as in Example 2 were used. The difference was that the mass concentrations of each substance in the liquid phase containing nitric acid and methanol were: nitric acid 5.4%, methanol 54.6%, and water 40%; and the volume concentrations of each substance in the gaseous phase containing nitric oxide were: NO 15%, CO 15%, and N2 70%.

[0094] Using the above technical solution, the conversion rate of nitric acid is 96.10%.

[0095] Example 4

[0096] The nitric acid conversion reactor is a series of six circulating reactors. In the first stage reactor, the ratio of the diameter of the guide tube to the reactor diameter is 0.4, the ratio of the guide tube height to the diameter is 4, and the ratio of the height of the gap from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.2. The gas distributor is annular, and its equivalent diameter is 0.6 times the diameter of the guide tube. The reaction temperature is 60℃, the gas-liquid volume ratio is 500, and the liquid phase residence time is 1 hour. In the second and third stage reactors, the ratio of the diameter of the guide tube to the reactor diameter is 0.7, the ratio of the guide tube height to the diameter is 9, and the ratio of the height of the gap from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.32. The gas distributor is annular, and its equivalent diameter is 0.7 times the diameter of the guide tube. The reaction temperature is 75℃, the gas-liquid volume ratio is 400, and the liquid phase residence time is 1.5 hours. For the fourth and fifth stage reactors, the ratio of the guide tube diameter to the reactor diameter is 0.7, the ratio of the guide tube height to the diameter is 12, and the ratio of the gap height from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.3. The gas distributor is an annular distributor with an equivalent diameter 0.7 times the diameter of the guide tube. The reaction temperature is 85℃, the gas-liquid volume ratio is 300, and the liquid phase residence time is 2 hours. For the sixth stage reactor, the ratio of the guide tube diameter to the reactor diameter is 0.8, the ratio of the guide tube height to the diameter is 15, and the ratio of the gap height from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.4. The gas distributor is an annular distributor with an equivalent diameter 0.8 times the diameter of the guide tube. The reaction temperature is 100℃, the gas-liquid volume ratio is 200, and the liquid phase residence time is 2 hours.

[0097] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 10%, methanol 65%, water 25%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 20%, CO 10%, N2 70%.

[0098] Using the above technical solution, the conversion rate of nitric acid is 99.34%.

[0099] Example 5

[0100] The nitric acid conversion reactor is a two-stage circulating reactor connected in series. In the first stage reactor, the ratio of the diameter of the guide tube to the reactor diameter is 0.6, the ratio of the guide tube height to its diameter is 8, and the ratio of the height of the gap from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.3. The gas distributor is a dendritic distributor, and its equivalent diameter is 0.7 times the diameter of the guide tube. The reaction temperature is 78℃, the gas-liquid volume ratio is 800, and the liquid phase residence time is 2 hours. In the second stage reactor, the ratio of the diameter of the guide tube to the reactor diameter is 0.7, the ratio of the guide tube height to its diameter is 10, and the ratio of the height of the gap from the lower edge of the guide tube to the bottom of the reactor to the reactor diameter is 0.35. The gas distributor is also a dendritic distributor, and its equivalent diameter is 0.7 times the diameter of the guide tube. The gas-liquid volume ratio of the liquid phase to the gas phase is 500, the reaction temperature is 95℃, and the liquid phase residence time is 4 hours.

[0101] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 6.7%, methanol 70.3%, and water 23%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 28%, CO 12%, and N2 70%.

[0102] Using the above technical solution, the conversion rate of nitric acid is 99.22%.

[0103] Example 6

[0104] The same nitric acid conversion reactor as in Example 1 was used, except that the reaction was carried out at a reaction temperature of 80°C, a gas-liquid volume ratio of 900, and a liquid phase residence time of 3 hours.

[0105] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 1%, methanol 64%, water 35%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 16%, CO 14%, N2 70%.

[0106] Using the above technical solution, the conversion rate of nitric acid is 95.68%.

[0107] Example 7

[0108] The same nitric acid conversion reactor as in Example 2 was used, except that the reaction was carried out under the conditions of a gas-liquid volume ratio of 300 v / v, a reaction temperature of 90°C, and a liquid phase residence time of 4 h.

[0109] The mass concentrations of each substance in the liquid phase material containing nitric acid and methanol are: nitric acid 3.6%, methanol 76.4%, and water 20%; the volume concentrations of each substance in the gaseous phase material containing nitric oxide are: NO 15%, CO 16%, and N2 69%.

[0110] Using the above technical solution, the conversion rate of nitric acid is 97.26%.

[0111] As can be seen from the above technical solutions, the circulating reaction device and reaction method provided by the present invention have the advantages of high material conversion rate, high mass transfer efficiency, short reaction time, and controllable device size, effectively solving the problems of large reactor equipment, long liquid phase residence time, difficult sealing, high energy consumption, and low material conversion rate in the prior art.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A circulating reaction apparatus, characterized in that, The device includes at least one circulating reactor, the circulating reactor including a cylindrical body and a guide tube disposed inside the cylindrical body, wherein an annular gap is formed between the cylindrical body and the guide tube; The circulating reactor is equipped with a liquid material inlet, a gas material inlet, and a gas distributor. The gas material enters the guide tube through the gas material inlet and the gas distributor.

2. The circulating reaction apparatus according to claim 1, wherein, The ratio D of the diameter of the guide tube to the diameter of the circulating reactor is 0.3-0.9, preferably 0.4-0.8; And / or, the height-to-diameter ratio E of the guide tube is 4-20, preferably 4-15; And / or, the ratio F of the gap height from the lower edge of the guide tube to the bottom of the circulating reactor to the diameter of the circulating reactor is 0.1-0.5, preferably 0.2-0.

4.

3. The circulating reaction apparatus according to claim 2, wherein, The D value of the subsequent circulating reactor is not lower than the D value of the previous circulating reactor; And / or, the E value of the subsequent circulating reactor is not lower than the E value of the preceding circulating reactor; And / or, the F value of the subsequent circulating reactor is not lower than the F value of the preceding circulating reactor.

4. The circulating reactor according to any one of claims 1-3, wherein, The equivalent diameter of the gas distributor is no greater than 0.8 times the diameter of the guide tube, preferably 0.6-0.8 times; Preferably, the gas distributor is a dendritic distributor or a ring distributor; Preferably, the gas distributor is located at the bottom of the circulating reactor; Preferably, the plane containing the nozzle of the gas distributor is not lower than the lower edge of the bottom of the guide tube.

5. The circulating reactor according to any one of claims 1-4, wherein, The device comprises 1-6 stages, preferably 2-4 stages, of circulating reactors connected in series, wherein the liquid phase material outlet of the preceding stage is connected to the liquid phase inlet of the following stage.

6. The circulating reactor according to any one of claims 1-5, wherein, The liquid material inlet of the first-stage circulating reactor is connected to a liquid material supply unit containing nitric acid and methanol, for feeding the liquid material containing nitric acid and methanol into the first-stage circulating reactor; Preferably, the gaseous material inlet of each stage of the circulating reactor is connected to a gaseous material supply unit containing nitric oxide, for introducing gaseous material containing nitric oxide into each stage of the circulating reactor.

7. A reaction method using the circulating reactor according to any one of claims 1-6, the method comprising: In the circulating reactor, gaseous material enters the guide tube through the gas inlet via the gas distributor and reacts with liquid material fed through the liquid inlet.

8. The method according to claim 7, wherein, The gaseous material is a gaseous material containing nitric oxide. Preferably, the volume concentration of nitric oxide in the gaseous material containing nitric oxide is 10-100%. More preferably, the volume concentration of nitric oxide in the gaseous material containing nitric oxide is 15-80%, the volume concentration of carbon monoxide is 0-30%, and the inert gas is preferably nitrogen with a volume concentration of 20-80%.

9. The method according to claim 7, wherein, The liquid phase material is a liquid phase material containing nitric acid and methanol. Preferably, in the liquid phase material containing nitric acid and methanol, the mass concentration of methanol is 50-90% and the mass concentration of nitric acid is 0.1-10%. More preferably, in the liquid phase material containing nitric acid and methanol, the mass concentration of methanol is 60-90%, the mass concentration of nitric acid is 0.5-10%, and the mass concentration of water is 0-30%.

10. The method according to any one of claims 7-9, wherein, The reaction temperature in the circulating reactor is 40-120℃, the volume ratio of gaseous material inlet to liquid material inlet is 200-900, and the liquid phase residence time is 0.5-6h. Preferably, the reaction temperature in the circulating reactor is 60-100℃, the volume ratio of gaseous material inlet to liquid material inlet is 200-800, and the liquid phase residence time is 1-6h. More preferably, the reaction temperature in the subsequent circulating reactor is not lower than the reaction temperature in the preceding circulating reactor. Preferably, the liquid phase residence time in the subsequent circulating reactor is not less than the liquid phase residence time in the preceding circulating reactor.

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