A high pressure relief device and a high pressure relief method for an LDPE process

Abstract

The present application relates to the technical fields of high pressure gas release, and discloses a high pressure release device and a high pressure release method for LDPE process. The high pressure release device comprises a release pipe, and one or more fire retardant release units are arranged on the lateral wall of the release pipe. Each fire retardant release unit comprises a micro-channel bubble generator, a fire retardant tank and a solvent tank. The inlet of the micro-channel bubble generator is connected with the fire retardant tank and the solvent tank respectively, and the outlet is connected with the release pipe. The fire retardant from the fire retardant tank and the solvent from the solvent tank are contacted in the micro-channel bubble generator to form micro-bubbles, and then enter the release pipe. The micro-channel bubble generator is installed on the lateral side of the existing release pipe, so that the fire retardant is injected into the release pipe in the form of micro-bubbles, thereby being uniformly mixed with the release gas, and then the fire can be quickly extinguished and explosion can be suppressed. The device is convenient to install, has excellent fire extinguishing and explosion suppression effect, is flexible to operate, and is suitable for the release of high temperature and high pressure combustible gas in various types of processes.

Description

Technical Field

[0001] This invention relates to the field of high-pressure gas venting technology, specifically to a high-pressure venting device and a high-pressure venting method for LDPE processes. Background Technology

[0002] In chemical synthesis processes, the release of high-pressure gases is frequently involved. Taking high-pressure polyethylene (HDPE) as an example, HDPE, also known as low-density polyethylene (LDPE), is a thermoplastic resin. As a key polymer material, it has broad application prospects in the processing and manufacturing of electrical insulation products, boasts a large market, and is an indispensable chemical material worldwide. HDPE processes are mainly divided into tubular and batch processes. The tubular process primarily produces HDPE granules and plastic products, while the batch process is mainly used for producing film plastics and coated resin products. In HDPE processes, the ethylene polymerization pressure is between 200 and 300 MPa, the reaction temperature is between 150 and 310°C, and the production method is continuous. When the system is under abnormal conditions (the reactor temperature or pressure is higher than the normal reaction temperature or pressure), emergency depressurization of the reactor is required.

[0003] Currently, industrial production primarily uses straight venting pipes to directly release gases into the atmosphere, employing water spraying for flame arrest and cooling during the venting process. However, the sprayed water mainly flows downwards along the inner wall of the venting pipe, resulting in uneven mixing with the vented gas and posing a significant risk of combustion and explosion. Another method is to vent into a water tank; however, after the combustible gas is cooled by water, it enters the upper gas phase space of the venting tank, still posing a risk of secondary combustion and explosion. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem in the prior art where water entering the vent pipe by spraying does not mix evenly with high-temperature and high-pressure gas, resulting in poor flame arrest and explosion suppression effects and posing a risk of combustion and explosion. This invention provides a high-pressure venting device and a high-pressure venting method for LDPE processes. This high-pressure device can safely vent various types of high-temperature and high-pressure combustible gases.

[0005] To achieve the above objectives, the present invention provides a high-pressure relief device, which includes a relief pipe. One or more flame retardant release units are disposed on the side wall of the relief pipe. Each flame retardant release unit includes a microchannel bubble generator, a flame retardant tank, and a solvent tank. The inlet of the microchannel bubble generator is connected to the flame retardant tank and the solvent tank, respectively, and the outlet is connected to the relief pipe. The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact with each other in the microchannel bubble generator to form microbubbles, which then enter the relief pipe.

[0006] Preferably, the installation angle between each microchannel bubble generator and the vent pipe is 20 to 80°.

[0007] Preferably, each of the microchannel bubble generators includes an air inlet pipe, a liquid inlet pipe, a mixing pipe, and an output pipe.

[0008] The inlet end of the air intake pipe is connected to the flame retardant tank, and the outlet end is connected to the mixing pipe.

[0009] The inlet end of the liquid inlet pipe is connected to the solvent tank, and the outlet end is connected to the mixing pipe;

[0010] The inlet end of the output pipe is connected to the mixing pipe, and the outlet end is connected to the discharge pipe.

[0011] Preferably, in each of the microchannel bubble generators, the diameter of the air inlet pipe, liquid inlet pipe, mixing pipe, and output pipe is 100–800 μm.

[0012] Preferably, the number of flame retardant release units is 2.

[0013] Preferably, along the airflow direction, a first flame retardant release unit and a second flame retardant release unit are sequentially arranged on the side wall of the vent pipe, wherein the flame retardant provided in the first flame retardant release unit and the second flame retardant release unit may be the same or different.

[0014] Preferably, the high-pressure relief device further includes a relief valve, which is located at the air inlet end of the relief pipe.

[0015] A second aspect of the present invention provides a high-voltage venting method for LDPE processes, the method being implemented in a high-voltage venting device as described above, the method comprising:

[0016] The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact in the microchannel bubble generator to form microbubbles, which then enter the vent pipe and mix with the vent gas from the LDPE reactor.

[0017] Preferably, along the airflow direction, a first flame retardant release unit and a second flame retardant release unit are sequentially arranged on the side wall of the vent pipe. The vent gas from the reactor enters the vent pipe and mixes sequentially with the microbubbles released by the first flame retardant release unit and the microbubbles released by the second flame retardant release unit.

[0018] Preferably, the first flame retardant release unit includes a first flame retardant tank, a first microchannel bubble generator, and a first solvent tank, and the second flame retardant release unit includes a second flame retardant tank, a second microchannel bubble generator, and a second solvent tank;

[0019] Wherein, the first fire retardant tank is filled with a first fire retardant, and the second fire retardant tank is filled with a second fire retardant, and the first fire retardant and the second fire retardant may be the same or different.

[0020] The first solvent tank is filled with a first solvent, and the second solvent tank is filled with a second solvent. The first solvent and the second solvent may be the same or different.

[0021] Preferably, the first flame retardant contains carbon dioxide, and the second flame retardant contains a foaming agent, an antifreeze agent, a foam stabilizer, an anti-burning agent, a preservative, and a pH adjuster.

[0022] Preferably, in the second flame retardant, the weight ratio of foaming agent, antifreeze agent, foam stabilizer, anti-burning agent, preservative and pH adjuster is 40:20-40:10-20:5-13:2-7:2-4.

[0023] Preferably, the foaming agent is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and fatty alcohol polyoxyethylene ether sulfate;

[0024] Preferably, the antifreeze is selected from at least one of ethanol, ethylene glycol, and propylene glycol;

[0025] Preferably, the anti-burning agent is tetrahydrofuran resin and / or sodium dihydrogen phosphate;

[0026] Preferably, the preservative is sodium benzoate and / or potassium sorbate;

[0027] Preferably, the pH adjuster is sodium hydrogen phosphate and / or ammonium bicarbonate.

[0028] Preferably, during the release process, the flow rate ratio of the first flame retardant to the first solvent is maintained at 1:3 to 7;

[0029] Preferably, during the release process, the flow rate ratio of the second flame retardant and the second solvent is maintained at 1:5 to 9.

[0030] Preferably, the microchannel bubble generator includes an air inlet pipe, a liquid inlet pipe, a mixing pipe, and an output pipe, wherein the inlet end of the air inlet pipe is connected to the flame retardant tank and the outlet end is connected to the mixing pipe; the inlet end of the liquid inlet pipe is connected to the solvent tank and the outlet end is connected to the mixing pipe; the inlet end of the output pipe is connected to the mixing pipe and the outlet end is connected to the vent pipe.

[0031] Preferably, the residence time of the material in the mixing pipe and the output pipe is 0.1 to 1 second.

[0032] The technical solution provided by this invention involves installing a microchannel generator on the side of an existing vent pipe. This allows the flame retardant to be injected into the vent pipe in the form of microbubbles. The microbubbles are more evenly distributed radially within the vent pipe, resulting in more uniform mixing with the vented gas and thus enabling rapid flame arrest and explosion suppression. The high-pressure venting device provided by this invention is easy to install, has excellent flame arrest and explosion suppression effects, and is flexible in operation. It is suitable for venting high-temperature and high-pressure combustible gases in various processes, such as venting in the LDPE process. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of one embodiment of the high-pressure relief device provided by the present invention in conjunction with a reaction vessel.

[0034] Explanation of reference numerals in the attached figures

[0035] 10-Relief pipe; 11-Relief valve; 20a-First flame retardant release unit; 211-First flame retardant tank; 212-First solvent tank; 213-First microchannel bubble generator; 20b-Second flame retardant release unit; 221-Second flame retardant tank; 222-Second solvent tank; 223-Second microchannel bubble generator; 231-Air inlet pipe; 232-Liquid inlet pipe; 233-Mixing pipe; 234-Outlet pipe;

[0036] 300-Reaction vessel. Detailed Implementation

[0037] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0038] 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.

[0039] In the synthesis of polyolefins, the release of high-pressure gases is often involved. Taking low-density polyethylene (LDPE) as an example, existing LDPE processes all use a straight-pipe release method. Currently, the common practice is to trigger an interlock during release, causing the straight pipe to spray water into a side tank to cool and extinguish the flame of the released gas. However, the spraying method results in uneven radial distribution of water, making it impossible for the water and the high-temperature, high-pressure gas to achieve a uniform distribution. This leads to poor flame-extinguishing and explosion-suppressing effects and poses a risk of combustion and explosion.

[0040] In view of this, the present invention provides a high-pressure relief device that injects a flame retardant in the form of microbubbles into the relief pipe, which can fully mix with the relief gas, thereby ensuring rapid flame arrest and explosion suppression. Please refer to the following references. Figure 1 The high-pressure relief device includes a relief pipe 10, on which one or more flame retardant release units are provided. Each flame retardant release unit includes a flame retardant tank, a solvent tank, and a microchannel bubble generator. The inlet of the microchannel bubble generator is connected to the flame retardant tank and the solvent tank, respectively, and the outlet is connected to the relief pipe 10. The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact with each other in the microchannel bubble generator to form microbubbles, which then enter the relief pipe 10.

[0041] In this invention, the discharge pipe 10 is a direct-structure discharge pipe 10, also known as a discharge straight pipe.

[0042] This invention involves installing one or more flame retardant release units on the side of an existing venting straight pipe. Each flame retardant release unit includes a microchannel bubble generator, a flame retardant tank, and a solvent tank. The flame retardant and solvent contact each other in the microchannel generator, causing the flame retardant to be sprayed into the venting straight pipe in the form of microbubbles and mixed with the vented gas, thereby achieving flame arrest. This invention introduces the flame retardant into the venting pipe 10 in the form of microbubbles, resulting in a more uniform radial distribution within the venting pipe 10, thus achieving more uniform mixing with the vented gas and a better flame arrest and explosion suppression effect. This enables the safe venting of high-temperature, high-pressure combustible gases. The device provided by this invention can quickly arrest flames during the venting process, is easy to install, has excellent flame arrest and explosion suppression effects, is flexible in operation, and is suitable for various types of high-temperature, high-pressure combustible gas venting processes.

[0043] In this invention, the high-pressure relief device further includes a relief valve 11, which is located at the inlet end of the relief pipe 10. The inlet end refers to the entrance end of the relief pipe for releasing gas. Specifically, the relief pipe 10 is connected to the reactor 300 via the relief valve 11. By controlling the opening and closing of the relief valve 11, gas from the reactor 300 can be released into the relief pipe 10 when necessary.

[0044] When the high-pressure relief device described in this invention is used for relief in the LDPE process, the relief process is as follows: Under abnormal operating conditions (the system temperature is 2°C higher than the normal reaction temperature or the pressure is 3MPa higher than the reaction pressure), the interlocking valve is opened and the microchannel bubble generator is started to inject the formed microbubbles into the relief pipe 10 and mix them with the relief gas, so as to ensure that the relief gas does not burn or explode during the process of being discharged to the atmosphere.

[0045] In this invention, the volume of the reactor 300 is 200-400L, the material is 316L, the system temperature is 220-240℃, and the pressure is 100-250MPa.

[0046] In a specific implementation, the venting straight pipe is made of 316L, with a design pressure of 500℃ and 500MPa, and a length of 30-50m.

[0047] In order to make the flame retardant microbubbles injected by the microchannel bubble generator mix more evenly with the vented gas, in this invention, the installation angle α between each microchannel bubble generator and the venting pipe 10 is 20-80°.

[0048] The present invention does not limit the specific structure of the microchannel bubble generator, and it can be a commonly used microchannel bubble generator. In a specific embodiment, each microchannel bubble generator includes an air inlet pipe 231, a liquid inlet pipe 232, a mixing pipe 233, and an output pipe 234. The inlet end of the air inlet pipe 231 is connected to the flame retardant tank, and the outlet end is connected to the mixing pipe 233. The inlet end of the liquid inlet pipe 232 is connected to the solvent tank, and the outlet end is connected to the mixing pipe 233. The inlet end of the output pipe 234 is connected to the mixing pipe 233, and the outlet end is connected to the vent pipe 10.

[0049] In a preferred embodiment, the diameter of each pipe (air inlet pipe 231, liquid inlet pipe 232, mixing pipe 233, and output pipe 234) in each microchannel bubble generator is 100–800 μm. In this document, pipe diameter refers to the inner diameter.

[0050] Considering both cost and fire-retardant and explosion-suppressing effects, in a preferred embodiment, the number of fire-retardant release units is 2.

[0051] Specifically, the two flame retardant release units are a first flame retardant release unit 20a and a second flame retardant release unit 20b, which are arranged along the airflow direction (venting direction). In practice, the venting gas from the reactor 300 enters the vent pipe 10, first mixes with the flame retardant released by the first flame retardant release unit 20a installed at the lower end, then continues to move upward and mixes with the flame retardant released by the second flame retardant release unit 20b, and finally is discharged into the atmosphere.

[0052] In this invention, the flame retardants provided in the first flame retardant release unit 20a and the second flame retardant release unit 20b are the same or different, preferably different. By selecting different types of flame retardants, the combustible gas is mixed with a variety of microbubbles during the release process, which greatly reduces the risk of combustion and explosion caused by friction between the high-temperature and high-pressure combustible gas and the inner wall of the release pipe 10 during the release process.

[0053] In order to better mix the vented gas with the flame retardant provided in the first flame retardant release unit 20a and the second flame retardant release unit 20b, in a preferred embodiment, the first flame retardant release unit 20a and the second flame retardant release unit 20b are alternately arranged along the circumference of the vent pipe 10.

[0054] Furthermore, the first flame retardant release unit 20a includes a first flame retardant tank 211, a first solvent tank 212, and a first microchannel bubble generator 213, and the second flame retardant unit includes a second flame retardant tank 221, a first solvent tank 212, and a second microchannel bubble generator 223.

[0055] In this invention, when there are two flame retardant release units, the interlock signal activation logic is as follows: first, the first microchannel bubble generator 213 is activated; after 3 to 5 seconds, the second microchannel bubble generator 223 is activated; and finally, after 1 to 2 seconds, the top vent valve 11 of the reactor 300 is activated.

[0056] The present invention does not limit the installation interval between the first microchannel generator and the second microchannel generator on the vent pipe 10, and can be designed according to actual working conditions. In a preferred embodiment, the installation interval between the first microchannel generator and the second microchannel generator is 20% to 70% of the total length of the vent pipe 10.

[0057] In one specific embodiment, the length of the discharge pipe 10 is 30-50m, wherein the first microchannel bubble generator 213 is installed at a distance of 115-10m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 1120-25m from the discharge valve.

[0058] The present invention also provides a high-voltage venting method for LDPE processes, which is implemented in the high-voltage venting device described above, and the method includes:

[0059] The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact in the microchannel bubble generator to form microbubbles, which then enter the vent pipe 10 and mix with the vent gas from the LDPE reactor 300.

[0060] In a specific embodiment, the number of flame retardant release units is two. More specifically, a first flame retardant release unit 20a and a second flame retardant release unit 20b are sequentially arranged on the side wall of the vent pipe 10. The vented gas from the reactor 300 enters the vent pipe 10 and mixes sequentially with the microbubbles released by the first flame retardant release unit 20a and the second flame retardant release unit 20b.

[0061] Furthermore, the first flame retardant release unit 20a includes a first flame retardant tank 211, a first microchannel bubble generator 213, and a first solvent tank 212, and the second flame retardant release unit 20b includes a second flame retardant tank 221, a second microchannel bubble generator 223, and a second solvent tank 222.

[0062] In a specific embodiment, the first fire retardant tank 211 is filled with a first fire retardant, and the second fire retardant tank 221 is filled with a second fire retardant. The first fire retardant and the second fire retardant may be the same or different.

[0063] In a specific embodiment, the first solvent tank 212 is filled with a first solvent, and the second solvent tank 222 is filled with a second solvent. The first solvent and the second solvent may be the same or different.

[0064] This invention does not limit the specific types of the first and second flame retardants. In a preferred embodiment, the first flame retardant contains carbon dioxide, and the second flame retardant contains a foaming agent, an antifreeze agent, a foam stabilizer, an anti-burning agent, a preservative, and a pH adjuster. By selecting the above-mentioned types of flame retardants, the released gas is first mixed with the first flame retardant, which is more environmentally friendly and has a lower cost, and then mixed with the second flame retardant, which has a better flame retardant and explosion suppression effect. In this way, the flame retardant and explosion suppression effect is good, and the cost is lower and the environmental protection is better.

[0065] More preferably, in the second flame retardant, the weight ratio of foaming agent, antifreeze agent, foam stabilizer, anti-burning agent, preservative and pH adjuster is 40:20-40:10-20:5-13:2-7:2-4.

[0066] In some embodiments, the foaming agent is a nonionic hydrocarbon surfactant, preferably at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and fatty alcohol polyoxyethylene ether sulfate.

[0067] In some embodiments, the antifreeze is an alcohol, preferably at least one of ethanol, ethylene glycol, and propylene glycol.

[0068] In a preferred embodiment, the anti-burning agent is tetrahydrofuran resin and / or sodium dihydrogen phosphate.

[0069] In a preferred embodiment, the preservative is sodium benzoate and / or potassium sorbate.

[0070] In a preferred embodiment, the pH adjuster is sodium hydrogen phosphate and / or ammonium bicarbonate.

[0071] In a specific embodiment, the first solvent tank 212 is used to provide water, preferably deionized water.

[0072] In a specific embodiment, the second solvent tank 222 is used to provide water, preferably deionized water.

[0073] In this invention, a first microchannel generator and a second microchannel generator are installed laterally on the existing vent pipe. The first microchannel bubble generator 213 uses carbon dioxide and water to generate a fine water mist carrying carbon dioxide microbubbles, which is then sprayed into the vent pipe for flame arrest. The second microchannel bubble generator 223 uses a foaming method, co-entering the microchannel with a solvent to generate foam, which is then sprayed into the vent pipe to ensure sufficient flame arrest for the vented gas. This invention, by spraying the flame retardant into the vent pipe 10 in the form of microbubbles, achieves a more uniform radial distribution within the vent pipe 10, resulting in more uniform mixing with the vented gas and a better flame arrest and explosion suppression effect.

[0074] In the method described in this invention, each microchannel bubble generator includes an air inlet pipe 231, a liquid inlet pipe 232, a mixing pipe 233, and an output pipe 234. The inlet end of the air inlet pipe 231 is connected to the flame retardant tank, and the outlet end is connected to the mixing pipe 233. The inlet end of the liquid inlet pipe 232 is connected to the solvent tank, and the outlet end is connected to the mixing pipe 233. The inlet end of the output pipe 234 is connected to the mixing pipe 233, and the outlet end is connected to the vent pipe 10.

[0075] In a preferred embodiment, in each of the microchannel bubble generators, the diameter of each pipe (air inlet pipe 231, liquid inlet pipe 232, mixing pipe 233 and output pipe 234) is 100 to 800 μm.

[0076] In this invention, the diameters of the pipes in the first microchannel bubble generator 213 and the second microchannel bubble generator 223 may be the same or different.

[0077] In order to better form microbubbles and improve the fire-retardant and explosion-suppressing effect, in a preferred embodiment, the diameter of each pipe in the first microchannel bubble generator 213 is 100-500μm, more preferably 200-300μm, and the diameter of the second microchannel bubble generator 223 is 200-800μm, more preferably 400-500μm.

[0078] In order to better form microbubbles, in a preferred embodiment, during the release process, the flow rate ratio of the first flame retardant to the first solvent in the first flame retardant release unit 20a is maintained at 1:3 to 7.

[0079] The present invention does not limit the specific amount of the first fire retardant in the first fire retardant tank 211, and it can be designed according to actual working conditions. In one specific embodiment, the volume of the first fire retardant filled in the first fire retardant tank 211 is 3-10 m³. 3 In one specific embodiment, the volume of the first solvent filled in the first solvent tank 212 is 3 to 10 m³. 3 .

[0080] In order to better form microbubbles, in a preferred embodiment, during the venting process, the flow rate ratio of the second flame retardant and the second solvent in the second flame retardant release unit 20b is maintained at 1:5 to 9.

[0081] The present invention does not limit the specific amount of the second fire retardant filled in the second fire retardant tank 221, and can be designed according to actual working conditions. In one specific embodiment, the volume of the second fire retardant filled in the second fire retardant tank 221 is 2-5 m³. 3 In another specific embodiment, the volume of the second solvent filled in the second solvent tank 222 is 2-5 m³. 3 .

[0082] In a preferred embodiment, the material resides in the mixing pipe 233 and the output pipe 234 of the microchannel bubble generator for 0.1 to 1 second.

[0083] In a more preferred embodiment, the residence time of the materials (i.e., the first flame retardant and the first solvent) in the mixing pipe 233 and the output pipe 234 of the first microchannel bubble generator 213 is 0.1 to 0.3 seconds.

[0084] In a more preferred embodiment, the residence time of the material (i.e., the second flame retardant and the second solvent) in the mixing pipe 233 and the output pipe 234 of the second microchannel bubble generator 223 is 0.4 to 1.0 seconds.

[0085] The method provided by this invention can be applied to the safe release of gas in the LDPE process system under abnormal (extreme) conditions, thereby achieving the purpose of flame arrest and explosion suppression.

[0086] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0087] In the following examples, the dispersion was tested according to the method described in GB / T 42844-2023, where θ A θ: The dispersion degree of microbubble A within the vent pipe after it is injected into the vent pipe;B The dispersion degree of microbubble B within the vent pipe after it is injected into the vent pipe.

[0088] The temperature drop was measured directly using a temperature sensor, where T A The temperature drop inside the vent pipe caused by microbubble A entering the vent pipe is measured at the outlet temperature of the first bubble generator; T B The temperature drop inside the vent pipe caused by microbubble B entering the vent pipe is measured at the outlet temperature of the second bubble generator.

[0089] Test method for microbubble diameter: GB / Z 44387-2024.

[0090] The following examples use Figure 1 The apparatus shown is implemented in a high-pressure venting device, which includes a venting straight pipe (venting pipe 10). Two flame retardant release units are provided on the side wall of the venting straight pipe, namely a first flame retardant release unit 20a and a second flame retardant release unit 20b arranged sequentially along the airflow direction (venting direction). The first flame retardant release unit 20a includes a first flame retardant tank 211, a first solvent tank 212, and a first microchannel bubble generator 213. The first flame retardant tank 211 is filled with a first flame retardant... The first solvent tank 212 is filled with a first solvent; the second flame retardant release unit 20b includes a second flame retardant tank 221, a second solvent tank 222, and a second microchannel bubble generator 223. The first flame retardant tank 211 is filled with a second flame retardant, and the first solvent tank 212 is filled with a second solvent. The first microchannel bubble generator 213 and the second microchannel bubble generator 223 both include an air inlet pipe 231, a liquid inlet pipe 232, a mixing pipe 233, and an output pipe 234.

[0091] In the following embodiments, the residence time of the fluid in the microchannel bubble reactor refers to the residence time in the mixing pipe 233 and the output pipe 234.

[0092] Example 1

[0093] The 200L LDPE reactor 300 needs to be depressurized. Normal operating conditions: reaction temperature 220℃, reaction pressure 200MPa. When the system is under abnormal operating conditions (temperature 2℃ higher than reaction temperature or pressure 3MPa higher than reaction pressure), the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on, then the second microchannel bubble generator 223 is turned on after 3 seconds, and finally the valve of the top relief valve 11 of the reactor 300 is turned on after 2 seconds.

[0094] The length of the discharge straight pipe is 30m. The first microchannel bubble generator 213 is installed at a distance of 116m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 22m from the discharge valve 11. The connection angle α between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 20°.

[0095] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 3m³. 3 The first flame retardant is carbon dioxide, the first solvent is deionized water, the flow rate ratio of the first flame retardant to the first solvent is 1:3, the diameter of each pipe in the first microchannel bubble generator 213 is 100 μm, the fluid residence time in the first microchannel bubble generator 213 is 0.1 seconds, and the generated microbubble A has a bubble diameter D. A The microbubble A, with a diameter of 150 μm, causes a temperature drop of T in the vent pipe after entering it. A The dispersion θ of microbubble A in the vent pipe is 40±2℃. A It is 30±1%;

[0096] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 2m³. 3 The second flame retardant contains: 40 parts foaming agent, 20 parts antifreeze, 15 parts foam stabilizer, 7 parts anti-burning agent, 3 parts preservative, and 3 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is a 1:1 volume mixture of ethanol and ethylene glycol, the anti-burning agent is tetrahydrofuran resin, the preservative is sodium benzoate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:5. The diameter of each pipe in the second microchannel bubble generator 223 is 200 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.4 seconds. The generated microbubble B has a bubble diameter D. B The microbubble B, with a diameter of 250 μm, causes a temperature drop of T inside the vent pipe after entering. B The dispersion θ of microbubble A in the vent pipe is 50±2℃. B It is 22±1%.

[0097] No explosion or fire occurred during the venting process in this embodiment.

[0098] Example 2

[0099] The 250L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 225℃ and the reaction pressure is 210MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 4 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0100] The length of the discharge straight pipe is 30m. The first microchannel bubble generator 213 is installed at a distance of 117m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 22m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 60°.

[0101] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 5m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:5. The diameter of each pipe in the first microchannel bubble generator 213 is 200 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.2 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (250 μm) enters the vent pipe is measured. A The temperature is 44±2℃, and the dispersion θ A It is 32±1%;

[0102] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 3m³. 3 The second flame retardant consists of 40 parts foaming agent, 25 parts antifreeze, 12 parts foam stabilizer, 8 parts anti-burning agent, 3 parts preservative, and 3 parts pH adjuster. The foaming agent is sodium dodecylbenzenesulfonate, the antifreeze is a 1:1 volume mixture of ethanol and ethylene glycol, the anti-burning agent is sodium dihydrogen phosphate, the preservative is potassium sorbate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:7. The diameter of each pipe in the second microchannel bubble generator 223 is 420 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.7 seconds. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B (400 μm) enters the vent pipe is measured. B The temperature is 56±2℃, and the dispersion θ B It is 24±1%.

[0103] No explosion or fire occurred during the venting process in this embodiment.

[0104] Example 3

[0105] The 300L LDPE reactor 300 needs to be depressurized. Under normal operating conditions: reaction temperature 220℃, reaction pressure 220MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on, then the second microchannel bubble generator 223 is turned on after 3 seconds, and finally the valve of the top relief valve 11 of the reactor 300 is turned on after 1 second.

[0106] The length of the discharge straight pipe is 30m. The first microchannel bubble generator 213 is installed at a distance of 118m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 20m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 80°.

[0107] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 8m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:7. The diameter of each pipe in the first microchannel bubble generator 213 is 300 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.3 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (350 μm) enters the vent pipe is measured. A The temperature is 47±2℃, and the dispersion θ A It is 35±1%;

[0108] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 4m³. 3 The second flame retardant contains: 40 parts foaming agent, 30 parts antifreeze agent, 15 parts foam stabilizer, 5 parts anti-burning agent, 5 parts preservative, and 2 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze agent is ethylene glycol, the anti-burning agent is tetrahydrofuran resin, the preservative is potassium sorbate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:9. The diameter of each pipe in the second microchannel bubble generator 223 is 600 μm. The fluid residence time in the first microchannel bubble generator 213 is 1.0 second. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B enters the vent pipe is 520 μm. B The temperature is 58±2℃, and the dispersion θ B It is 26±1%.

[0109] No explosion or fire occurred during the venting process in this embodiment.

[0110] Example 4

[0111] The 300L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 230℃ and the reaction pressure is 230MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 5 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0112] The length of the discharge straight pipe is 40m. The first microchannel bubble generator 213 is installed at a distance of 118m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 23m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 20°.

[0113] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 4m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:3. The diameter of each pipe in the first microchannel bubble generator 213 is 150 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.1 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (150 μm) enters the vent pipe is measured. A The temperature was 49±2℃, and the dispersion θ A It was 37±1%;

[0114] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 3m³. 3 The second flame retardant consists of 40 parts foaming agent, 22 parts antifreeze, 12 parts foam stabilizer, 5 parts anti-burning agent, 4 parts preservative, and 2 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is ethylene glycol, the anti-burning agent is tetrahydrofuran resin, the preservative is potassium sorbate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:5. The diameter of each pipe in the second microchannel bubble generator 223 is 300 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.4 seconds. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B (230 μm) enters the vent pipe is measured. B At 60±2℃, the dispersion θ BIt is 28±1%.

[0115] No explosion or fire occurred during the venting process in this embodiment.

[0116] Example 5

[0117] The 300L LDPE reactor 300 needs to be depressurized. Under normal operating conditions: reaction temperature 230℃, reaction pressure 240MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on, then the second microchannel bubble generator 223 is turned on after 5 seconds, and finally the valve of the top relief valve 11 of the reactor 300 is turned on after 1 second.

[0118] The length of the discharge straight pipe is 40m. The first microchannel bubble generator 213 is installed at a distance of 118m from the discharge valve. The first microchannel bubble generator 213 is installed at a distance of 24m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 60°.

[0119] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 5m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:5. The diameter of each pipe in the first microchannel bubble generator 213 is 200 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.2 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (260 μm) enters the vent pipe is measured. A The temperature is 55±2℃, and the dispersion θ A It is 43±1%.

[0120] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 3m³. 3 The second flame retardant consists of 40 parts foaming agent, 20 parts antifreeze, 15 parts foam stabilizer, 10 parts anti-burning agent, 5 parts preservative, and 2 parts pH adjuster. The foaming agent is a mixture of sodium dodecylbenzene sulfonate and fatty alcohol polyoxyethylene ether sulfate in a 1:1 weight ratio. The antifreeze is propylene glycol. The anti-burning agent is sodium dihydrogen phosphate. The preservative is potassium sorbate. The pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:7. The diameter of each pipe in the second microchannel bubble generator 223 is 400 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.7 seconds. The generated microbubble B has a bubble diameter D. BThe temperature drop T after microbubble B enters the vent pipe is 460 μm. B The temperature is 67±2℃, and the dispersion θ B It is 33±1%.

[0121] No explosion or fire occurred during the venting process in this embodiment.

[0122] Example 6

[0123] The 350L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 240℃ and the reaction pressure is 240MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 5 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0124] The length of the discharge straight pipe is 40m. The first microchannel bubble generator 213 is installed at a distance of 118m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 24m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 80°.

[0125] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 8m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:7. The diameter of each pipe in the first microchannel bubble generator 213 is 400 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.3 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A enters the vent pipe is 470 μm. A The temperature is 53±2℃, and the dispersion θ A It is 41±1%;

[0126] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 4m³. 3The second flame retardant consists of 30 parts foaming agent, 28 parts antifreeze, 14 parts foam stabilizer, 10 parts anti-burning agent, 2 parts preservative, and 3 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is a mixture of ethanol and ethylene glycol in a 1:2 volume ratio, the anti-burning agent is sodium dihydrogen phosphate, the preservative is sodium benzoate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:9. The diameter of each pipe in the second microchannel bubble generator 223 is 500 μm. The fluid residence time in the first microchannel bubble generator 213 is 1.0 second. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B enters the vent pipe is 670 μm. B The temperature is 65±2℃, and the dispersion θ B It is 30±1%.

[0127] No explosion or fire occurred during the venting process in this embodiment.

[0128] Example 7

[0129] The 350L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 240℃ and the reaction pressure is 250MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 5 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 1 second, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0130] The length of the discharge straight pipe is 50m. The first microchannel bubble generator 213 is installed at a distance of 119m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 22m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 20°.

[0131] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 5m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:3. The diameter of each pipe in the first microchannel bubble generator 213 is 150 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.1 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (190 μm) enters the vent pipe is measured. A The temperature is 48±2℃, and the dispersion θ A It was 34±1%;

[0132] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 3m³. 3 The second flame retardant consists of 40 parts foaming agent, 30 parts antifreeze, 15 parts foam stabilizer, 10 parts anti-burning agent, 2 parts preservative, and 2 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is propylene glycol, the anti-burning agent is tetrahydrofuran resin, the preservative is sodium benzoate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:5. The diameter of each pipe in the second microchannel bubble generator 223 is 300 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.4 seconds. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B (330 μm) enters the vent pipe is measured. B The temperature is 54±2℃, and the dispersion θ B It is 26±1%.

[0133] No explosion or fire occurred during the venting process in this embodiment.

[0134] Example 8

[0135] The 400L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 240℃ and the reaction pressure is 200MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 5 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0136] The length of the discharge straight pipe is 50m. The first microchannel bubble generator 213 is installed at a distance of 119m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 25m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 60°.

[0137] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 6m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:5. The diameter of each pipe in the first microchannel bubble generator 213 is 250 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.2 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (260 μm) enters the vent pipe is measured. A At 50±2℃, the dispersion θ AIt is 35±1%;

[0138] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 3m³. 3 The second flame retardant consists of 40 parts foaming agent, 20 parts antifreeze, 10 parts foam stabilizer, 10 parts anti-burning agent, 5 parts preservative, and 2 parts pH adjuster. The foaming agent is sodium dodecylbenzene sulfonate, the antifreeze is a mixture of ethanol and ethylene glycol in a 1:1 volume ratio, the anti-burning agent is sodium dihydrogen phosphate, the preservative is potassium sorbate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:7. The diameter of each pipe in the second microchannel bubble generator 223 is 400 μm. The fluid residence time in the first microchannel bubble generator 213 is 0.7 seconds. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B enters the vent pipe is 460 μm. B The temperature is 55±2℃, and the dispersion θ B It is 27±1%.

[0139] No explosion or fire occurred during the venting process in this embodiment.

[0140] Example 9

[0141] The 400L LDPE reactor 300 needs to be depressurized. Under normal operating conditions, the reaction temperature is 240℃ and the reaction pressure is 240MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 3 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top relief valve 11 of the reactor 300 is turned on.

[0142] The length of the discharge straight pipe is 50m. The first microchannel bubble generator 213 is installed at a distance of 1110m from the discharge valve 11, and the second microchannel bubble generator 223 is installed at a distance of 20m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 80°.

[0143] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 10m³. 3 The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:7. The diameter of each pipe in the first microchannel bubble generator 213 is 300 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.3 seconds. The generated microbubble A has a bubble diameter D. AThe temperature drop T after microbubble A enters the vent pipe is 460 μm. A The temperature is 52±2℃, and the dispersion θ A It was 36±1%;

[0144] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 4m³. 3 The second flame retardant consists of 40 parts foaming agent, 20 parts antifreeze, 13 parts foam stabilizer, 8 parts anti-burning agent, 5 parts preservative, and 3 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is ethanol, the anti-burning agent is tetrahydrofuran resin, the preservative is sodium benzoate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:9. The diameter of each pipe in the second microchannel bubble generator 223 is 700 μm. The fluid residence time in the first microchannel bubble generator 213 is 1.0 second. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B enters the vent pipe is 730 μm. B The temperature is 56±2℃, and the dispersion θ B It is 29±1%.

[0145] No explosion or fire occurred during the venting process in this embodiment.

[0146] Example 10

[0147] The 400L LDPE reactor 300 needs to be depressurized. Under normal operating conditions: the depressurization temperature is 240℃ and the reaction pressure is 240MPa. When the system temperature is 2℃ higher than the reaction temperature or the pressure is 3MPa higher than the reaction pressure, the depressurization interlock is triggered. First, the first microchannel bubble generator 213 is turned on. After 3 seconds, the second microchannel bubble generator 223 is turned on. Finally, after 2 seconds, the valve of the top depressurization valve 11 of the reactor 300 is turned on.

[0148] The length of the discharge straight pipe is 40m. The first microchannel bubble generator 213 is installed at a distance of 1110m from the discharge valve, and the second microchannel bubble generator 223 is installed at a distance of 25m from the discharge valve 11. The connection angle between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 60°.

[0149] In the first flame retardant release unit 20a, the volume of the first flame retardant filled in the first flame retardant tank 211 and the volume of the first solvent filled in the first solvent tank 212 are both 5m³. 3The flow rate ratio of the first flame retardant (carbon dioxide) to the first solvent (deionized water) is 1:3. The diameter of the first microchannel bubble generator 213 is 200 μm. The residence time of the fluid in the first microchannel bubble generator 213 is 0.1 seconds. The generated microbubble A has a bubble diameter D. A The temperature drop T after microbubble A (170 μm) enters the vent pipe is measured. A The temperature is 51±2℃, and the dispersion θ A It was 39±1%;

[0150] In the second flame retardant release unit 20b, the volume of the second flame retardant in the second flame retardant tank 221 and the volume of the second solvent in the second solvent tank 222 are both 4m³. 3 The second flame retardant consists of 40 parts foaming agent, 25 parts antifreeze, 12 parts foam stabilizer, 8 parts anti-burning agent, 3 parts preservative, and 2-3 parts pH adjuster. The foaming agent is sodium dodecyl sulfate, the antifreeze is a 1:1 volume mixture of ethanol and ethylene glycol, the anti-burning agent is sodium dihydrogen phosphate, the preservative is sodium benzoate, and the pH adjuster is sodium hydrogen phosphate. The second solvent is deionized water. The flow rate ratio of the second flame retardant to the second solvent is 1:9. The diameter of each pipe in the second microchannel bubble generator 223 is 800 μm. The fluid residence time in the first microchannel bubble generator 213 is 1.0 second. The generated microbubble B has a bubble diameter D. B The temperature drop T after microbubble B enters the vent pipe is 690 μm. B The temperature is 63±2℃, and the dispersion θ B It is 32±1%.

[0151] No explosion or fire occurred during the venting process in this embodiment.

[0152] Example 11

[0153] The method described in Example 4 is implemented, except that the connection angle α between the first microchannel bubble generator 213 and the second microchannel bubble generator 223 and the discharge straight pipe is 80°.

[0154] Test results show that the diameter D of the generated microbubble A is... A The temperature drop T after microbubble A (400 μm) enters the vent pipe is measured. A The temperature was 41±2℃, and the dispersion θ A The value is 30±1%. The diameter of the generated microbubble B is D. B The temperature drop T after microbubble B (600 μm) enters the vent pipe is measured. B The temperature is 55±2℃, and the dispersion θ B It is 27±1%.

[0155] No explosion or fire occurred during the venting process in this embodiment.

[0156] Example 12

[0157] The method described in Example 4 is implemented, except that the flow rate ratio of carbon dioxide to deionized water in the first microchannel bubble generator 213 is 1:7.

[0158] Test results show that the diameter D of the generated microbubble A is... A The temperature drop T after microbubble A (150 μm) enters the vent pipe is measured. A The temperature is 42±2℃, and the dispersion θ A It is 30±1%.

[0159] No explosion or fire occurred during the venting process in this embodiment.

[0160] Comparative Example 1

[0161] The method described in Example 4 is implemented, except that no flame arrestor release units are installed on either side of the vent pipe.

[0162] In this comparative example, during the venting process, the combustible gas rubs against the inner wall of the venting pipe, mixes with the air inside the pipe, and then explodes at the outlet of the venting pipe.

[0163] Comparative Example 2

[0164] The method described in Example 4 is implemented, except that the first microchannel bubble generator 213 and the second microchannel bubble generator 223 are both replaced with a pure deionized water tank spray device in an existing industrial device, which is connected to a discharge straight pipe for direct spraying.

[0165] In this comparative example, no microbubbles are generated, therefore there is no microbubble dispersion. Test results show that the first section of the straight pipe deionized water spray causes a temperature decrease of T. A The temperature drop T caused by the second-stage straight pipe deionized water spray was 28±2%. B It is 33±2%.

[0166] In this comparative example, during the venting process, the combustible gas rubs against the inner wall of the venting straight pipe, mixes with the air inside the pipe, and explodes when it is ejected from the venting straight pipe. A small drum flame phenomenon can be clearly seen at the main outlet of the venting pipe 10.

[0167] Comparative Example 3

[0168] The method described in Example 4 is implemented, except that the first microchannel bubble generator 213 and the second microchannel bubble generator 223 are both replaced with conventional spray devices, which are connected to the discharge straight pipe to directly spray the fire retardant.

[0169] In this comparative example, no microbubbles were generated, therefore there was no microbubble dispersion. Test results show that the spraying of the first flame retardant in the first straight pipe resulted in a temperature decrease of T. A The temperature drop T caused by the second section of the straight pipe being sprayed with the second flame retardant is 33±2%. B It is 40±2%.

[0170] 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 high-pressure relief device, characterized in that, The device includes a vent pipe (10), and one or more flame retardant release units are provided on the side wall of the vent pipe (10). Each flame retardant release unit includes a microchannel bubble generator, a flame retardant tank and a solvent tank. The inlet of the microchannel bubble generator is connected to the flame retardant tank and the solvent tank respectively, and the outlet is connected to the vent pipe. The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact with each other in the microchannel bubble generator to form microbubbles, which then enter the vent pipe (10).

2. The high-pressure relief device according to claim 1, characterized in that, The installation angle between each of the microchannel bubble generators and the vent pipe (10) is 20 to 80°.

3. The high-pressure relief device according to claim 1, characterized in that, Each of the microchannel bubble generators includes an air inlet pipe (231), a liquid inlet pipe (232), a mixing pipe (233), and an output pipe (234). The inlet end of the air intake pipe (231) is connected to the flame retardant tank, and the outlet end is connected to the mixing pipe (233). The inlet end of the liquid inlet pipe (232) is connected to the solvent tank, and the outlet end is connected to the mixing pipe (233); The inlet end of the output pipe (234) is connected to the mixing pipe (233), and the outlet end is connected to the discharge pipe (10).

4. The high-pressure relief device according to claim 3, characterized in that, In each of the microchannel bubble generators, the diameters of the air inlet pipe (231), liquid inlet pipe (232), mixing pipe (233), and output pipe (234) are all 100–800 μm.

5. The high-pressure relief device according to claim 1, characterized in that, The number of flame retardant release units is 2.

6. The high-pressure relief device according to claim 5, characterized in that, Along the airflow direction, a first flame retardant release unit (20a) and a second flame retardant release unit (20b) are sequentially arranged on the side wall of the vent pipe, wherein the flame retardant provided in the first flame retardant release unit (20a) and the second flame retardant release unit (20b) may be the same or different.

7. The high-pressure relief device according to any one of claims 1-6, characterized in that, The high-pressure relief device also includes a relief valve (11), which is located at the air inlet end of the relief pipe (10).

8. A high-pressure venting method for LDPE process, characterized in that, This method is implemented in the high-pressure relief device according to any one of claims 1-6, and the method includes: The flame retardant from the flame retardant tank and the solvent from the solvent tank come into contact in the microchannel bubble generator to form microbubbles, which then enter the vent pipe (10) and mix with the vent gas from the LDPE reactor (300).

9. The method according to claim 8, characterized in that, Along the airflow direction, a first flame retardant release unit (20a) and a second flame retardant release unit (20b) are sequentially arranged on the side wall of the vent pipe (10). The vent gas from the reactor (300) enters the vent pipe (10) and mixes sequentially with the microbubbles released by the first flame retardant release unit (20a) and the microbubbles released by the second flame retardant release unit (20b).

10. The method according to claim 9, characterized in that, The first flame retardant release unit (20a) includes a first flame retardant tank (211), a first microchannel bubble generator (213), and a first solvent tank (212); the second flame retardant release unit (20b) includes a second flame retardant tank (221), a second microchannel bubble generator (223), and a second solvent tank (222). The first fire retardant tank (211) is filled with a first fire retardant, and the second fire retardant tank (221) is filled with a second fire retardant. The first fire retardant and the second fire retardant may be the same or different. The first solvent tank (212) is filled with a first solvent, and the second solvent tank (222) is filled with a second solvent. The first solvent and the second solvent may be the same or different.

11. The method according to claim 10, characterized in that, The first flame retardant contains carbon dioxide, and the second flame retardant contains a foaming agent, an antifreeze agent, a foam stabilizer, an anti-burning agent, a preservative, and a pH adjuster.

12. The method according to claim 11, characterized in that, In the second flame retardant, the weight ratio of foaming agent, antifreeze agent, foam stabilizer, anti-burning agent, preservative and pH adjuster is 40:20-40:10-20:5-13:2-7:2-4.

13. The method according to claim 11 or 12, characterized in that, The foaming agent is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and fatty alcohol polyoxyethylene ether sulfate; Preferably, the antifreeze is selected from at least one of ethanol, ethylene glycol, and propylene glycol; Preferably, the anti-burning agent is tetrahydrofuran resin and / or sodium dihydrogen phosphate; Preferably, the preservative is sodium benzoate and / or potassium sorbate; Preferably, the pH adjuster is sodium hydrogen phosphate and / or ammonium bicarbonate.

14. The method according to claim 11, characterized in that, During the release process, the flow rate ratio of the first flame retardant to the first solvent is maintained at 1:3 to 7; Preferably, during the release process, the flow rate ratio of the second flame retardant and the second solvent is maintained at 1:5 to 9.

15. The method according to claim 8, characterized in that, The microchannel bubble generator includes an air inlet pipe (231), a liquid inlet pipe (232), a mixing pipe (233), and an output pipe (234). The inlet end of the air inlet pipe (231) is connected to the flame retardant tank, and the outlet end is connected to the mixing pipe (233). The inlet end of the liquid inlet pipe (232) is connected to the solvent tank, and the outlet end is connected to the mixing pipe (233). The inlet end of the output pipe (234) is connected to the mixing pipe (233), and the outlet end is connected to the vent pipe (10). Preferably, the material stays in the mixing pipe (233) and the output pipe (234) for 0.1 to 1 second.

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