Environment-friendly quenching device and on-line decoking process of the device

Abstract

The present application belongs to the technical field of decoking device and decoking process in petroleum chemical industry, and particularly relates to a green and environment-friendly quenching device and an online decoking process of the device. The online decoking process of the green and environment-friendly quenching device comprises the steps of quenching treatment of high-temperature cracking gas by a cracking quenching process and microwave pulse decoking of the quenching device according to the online decoking process. The present application provides an online decoking process of the green and environment-friendly quenching device, and solves the problems of continuous accumulation and blockage of viscous high-molecular-weight tar generated on the inner tube wall of the cracking quenching device in the traditional technology, short operation cycle of the cracking furnace, frequent decoking, large emission of greenhouse gases and harmful gases, short service life of the cracking furnace tube, high energy consumption and low production efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of decoking devices and processes in petrochemicals, specifically relating to a green and environmentally friendly quenching device and its online decoking process. Background Technology

[0002] Thermal pyrolysis refers to the process by which organic compounds decompose at high temperatures to produce products with different relative molecular masses. The 800℃ pyrolysis gas needs to be cooled by a waste heat boiler and then further cooled by a quencher to reduce its temperature to below 300℃; this process is called quenching. The quenching step is a crucial step in the thermal pyrolysis process. Its purpose is to rapidly cool the reacted materials in the high-temperature pyrolysis reactor to below the reaction temperature, thereby reducing secondary reactions and increasing the yield of the target product.

[0003] Currently, quench coolers are all shell-side structures, with the cooling medium in the shell side and the reactants in the tube side. The cooling medium in the shell side absorbs the heat released by the reactants in the tube side, thus cooling the material. The material exiting the pyrolysis furnace reactor directly enters the tube side of the quench cooler, where it is cooled before exiting the cooler, completing the quenching process. In actual production, the high-temperature reaction products entering the quench cooler tube side undergo partial condensation due to the sudden temperature drop. These condensed reaction products contain a large amount of olefins, which readily polymerize into high molecular weight substances at high temperatures. Some of these high molecular weight substances adhere to the inner wall of the tube side and are difficult to remove. Over time, the accumulated high molecular weight substances often cause blockages in the tube side, necessitating furnace shutdown and quench cooler regeneration.

[0004] Currently, traditional regeneration processes for quench coolers mostly employ the air burning method, which typically requires manual hydraulic cleaning after two air burning cycles. Therefore, a complete regeneration cycle includes two air burning cycles plus one manual cleaning cycle. The air burning method involves heating air and steam to approximately 800°C and introducing them into the quench cooler tubes. Without any catalysts or additives, the normal reaction temperature is between 800°C and 1300°C. This allows the hot air and steam to react with the coke layer within the tubes, producing carbon monoxide, carbon dioxide, and hydrogen. This high-temperature reaction releases large amounts of greenhouse gases and nitrogen oxides and consumes significant amounts of fuel gas and heat, making it neither environmentally friendly nor economical.

[0005] Because the quench cooler's structure is completely different from the furnace tubes of the upstream pyrolysis furnace, hot air and steam, upon reaching the tube side of the quench cooler, exchange heat with the quench water in the shell side, causing their temperature to drop sharply to around 300°C. This temperature is too low to reach the minimum 500°C required for the water-gas reaction, resulting in the inability to remove the coke layer; high molecular weight substances remain tightly adhered to the tube walls. Therefore, the problem of hydraulic decoking requiring two coking cycles persists. Manual hydraulic decoking is a physical removal method that typically requires completely stopping the pyrolysis furnace and disassembling the quench cooler head. Mechanical rotating heads and high-pressure water are used to physically clean the quench cooler. Since the quench cooler contains dozens or even hundreds of tubes, this method is time-consuming, labor-intensive, and prone to damaging the tube structure, causing quench cooler failure and affecting normal production. Furthermore, manual hydraulic decoking discharges a large amount of wastewater. Traditional decoking is quite expensive, costing approximately 1 million yuan per cycle, making it neither environmentally friendly nor economical.

[0006] CN204125428U discloses a pyrolysis gasification furnace with in-furnace coking removal function. This gasification furnace adds a microwave heating device between the refractory material of the carbon deposit reduction layer and the outer wall. This microwave heating device is used to increase the temperature within the carbon deposit reduction layer, allowing the tar formed by coking to reach approximately 950°C, the temperature required for catalytic cracking under carbon catalysis. However, the temperature used in this patent is too high, reaching 950°C, and is only suitable for gasification furnaces and heating furnaces. It is not suitable for low-temperature applications such as quench coolers. Furthermore, the unit energy efficiency ratio of non-pulsed microwaves is very low, making it unable to effectively remove high molecular weight tar.

[0007] The published paper in *Petroleum Refining and Chemical Engineering*, titled "Application of Online Coking Removal Technology in a 1-20 Mt_a Coking Furnace," combines variable-temperature and constant-temperature methods. It utilizes the scouring effect of steam on the coke deposit layer and the water-gas reaction between steam and coke at high temperatures to generate carbon monoxide and hydrogen. Taking advantage of the difference in thermal expansion coefficients between the metal furnace tubes and the coke deposit layer inside, the coke layer is detached from the furnace tubes by rapidly raising and lowering the furnace tube temperature. However, this method poses serious safety hazards because rapidly raising and lowering the furnace tube temperature can damage the tube material and furnace structure. Rapid temperature increases and decreases are strictly prohibited in the operating procedures of the heating furnace to avoid thermal fatigue of the metal material and damage to the insulation material! Furthermore, this method also releases large amounts of greenhouse gases and nitrogen oxides and consumes large quantities of fuel gas and fuel, making it neither environmentally friendly nor economical.

[0008] CN106520176B discloses a method for producing small molecule olefins from polyolefin plastics. First, the polyolefin plastic is cracked. The liquid / waxy product obtained from the cracking, along with optional liquid petroleum hydrocarbons, is mixed with water and subjected to microwave pyrolysis to obtain small molecule olefins. The polyolefin plastic is then fed into a mild cracking unit for further cracking. Gas-liquid separation yields a gaseous product a and a liquid / waxy product b. Product b is mixed with optional liquid petroleum hydrocarbons and water as a microwave pyrolysis feedstock. This feedstock is then mixed with water and fed into a microwave pyrolysis unit for microwave pyrolysis, followed by rapid cooling to below 500°C to obtain the pyrolysis products. This invention provides a method for microwave heating of microwave-insensitive hydrocarbon feedstocks, expanding the sources of feedstock for producing small molecule olefins. The internal heating characteristics of microwave heating improve the pyrolysis temperature and efficiency, while consuming less energy than traditional tubular pyrolysis furnaces. Summary of the Invention

[0009] The technical problem to be solved by this invention is to provide a green and environmentally friendly quenching device for online coking process, which solves the problems of viscous high molecular weight tar continuously accumulating and clogging the inner wall of the pyrolysis quencher tubes in the traditional technology, resulting in short operation cycle of pyrolysis furnace, frequent coking, large emissions of greenhouse gases and harmful gases, short service life of pyrolysis furnace tubes, high energy consumption and low production efficiency.

[0010] The online decoking process of the green and environmentally friendly quenching device of the present invention includes the step of quenching high-temperature pyrolysis gas using a pyrolysis quenching process, and the step of performing microwave pulse decoking on the quencher according to the online decoking process.

[0011] Based on the thermal cracking temperature rise to the transverse temperature range, high-power pulsed microwaves are used to utilize the reverse dissociation effect of microwaves to reverse dissociate the viscous high molecular weight tar generated on the inner wall of the quencher tube into small-molecule ethylene, propylene, and butadiene, which have high added value as gaseous and liquid products. These products flow out of the tube along with the gas and liquid phase mixture, reducing and inhibiting the formation of high molecular weight tar, and at the same time reducing the side reaction of high molecular weight tar condensation into coke. This fundamentally reduces the carbon source of greenhouse gases and is a green and environmentally friendly technology.

[0012] High-power pulsed microwaves have a power range of 0.1-40GW. They are S-band, X-band, or other band pulsed microwave sources with a peak power of 0.1W to 1000kW, a repetition frequency of 1kHz, a pulse width of 1ns to 1000ms, and a peak field strength of 0.1kV / m to 1000kV / m.

[0013] The aforementioned green and environmentally friendly rapid cooling device includes a microwave rapid cooler body and a high-power pulsed microwave reactor. The high-power pulsed microwave reactor includes a waveguide, a cooling radiator, a magnetron, a microwave generator, and an energy storage device. The microwave rapid cooler body is connected to the waveguide via a tube, the waveguide is connected to the magnetron, the magnetron is connected to the microwave generator, and the microwave generator is connected to the energy storage device. An upper and lower interface are provided at the connection between the waveguide and the magnetron, with a shielding layer between the upper and lower interfaces. The cooling radiator is installed on the waveguide. The cooling radiator can be air-cooled, water-cooled, or other heat dissipation structures, capable of reducing the high temperature to the microwave equipment's tolerance temperature.

[0014] The microwave generator is equipped with an explosion-proof control cabinet. The microwave generator converts electrical energy into pulsed microwave energy.

[0015] The microwave quencher body is located between the heating furnace and the product separation system. The waveguide of the high-power pulsed microwave reactor is connected to the furnace tube by a metal material, which can be a flange connection or welding. It is preferred to use a flange to achieve a compression connection to prevent the loss of high-power pulsed microwave energy.

[0016] The waveguide cavity is an inner conical cavity structure containing a shielding layer (which is also a heat dissipation layer), shaped like a horn, and is key to realizing the combined process of rapid cooling and high-power pulsed microwave defocusing. The magnetron and waveguide are a single combined structure. The high-power pulsed microwaves generated by the magnetron pass through the waveguide shielding layer and enter the tube side of the rapid cooler, acting on the material inside the tube side.

[0017] Waveguides have cross-sections that are cylindrical, conical, square, triangular, or any polygonal, and their end faces are either flat or curved. The horn shape of the waveguide minimizes reflection and scattering, effectively focusing high-power pulsed microwave energy and reducing transmission loss.

[0018] The waveguide is at an angle of 0° to 89° or 91° to 180° to the tube side, that is, it avoids being at right angles or perpendicular to the furnace tubes in the quencher tube side.

[0019] The magnetron is a pulsed microwave magnetron using a metal-dielectric cathode. Its advantages include a high repetition rate and long lifespan, with peak output beam current intensity (voltage 0.1–1 mV, current 1–10 kA) and pulse width (10 ns–1000 ms). The magnetron's operating frequency is not fixed, ranging from 250 MHz to 120 GHz. The appropriate operating frequency must be selected based on the properties and dielectric constant of the different raw materials, the process conditions of the heating furnace, and the operating cycle.

[0020] Multiple sets of high-power pulsed microwave reactors are installed on the microwave quencher body.

[0021] The shielding layer isolates the high-power pulsed microwave generator from the waveguide and is a combination of one or more non-polar materials such as ceramics, glass, polytetrafluoroethylene (PTFE), polypropylene, polyethylene, polysulfone, and mica. The rapid cooling process of this invention involves a high reaction temperature, and materials with strong thermal shock resistance, such as high-temperature modified PTFE, are preferred. The high-temperature modified PTFE undergoes a special ultrasonic microbubble filling process. The microbubbles in the modified PTFE enable it to simultaneously possess multiple properties, including heat insulation, chemical isolation, and high microwave permeability, making it one of the key components for implementing this invention.

[0022] The online decoking process of the green and environmentally friendly quenching device of this invention includes the step of quenching high-temperature pyrolysis gas using a pyrolysis quenching process, and the step of performing microwave pulse decoking on the quencher according to the online decoking process. The dissociation reaction mechanism of high molecular weight polymers is as follows:

[0023]

[0024] In traditional pyrolysis quench coolers, the reactions involving carbon, air, and steam primarily involve the following reactions:

[0025] C + H₂O = (high temperature) CO + H₂ (strong endothermic reaction)

[0026] C + 2H₂O = (high temperature) CO₂ + 2H₂ (Strongly endothermic reaction)

[0027] 2CO + O2 = 2CO2 (Exothermic reaction)

[0028] 2H₂ + O₂ = 2H₂O (Exothermic reaction)

[0029] N2 + O2 = 2NO

[0030] The microwave-assisted online decoking and quenching device of this invention includes a quencher body. Inside the quencher body is a high-power pulsed microwave reactor used to reverse-dissociate the viscous, high-molecular-weight tar generated on the inner wall of the quencher tubes into smaller gaseous and liquid components, which flow out of the reactor along with the reactants. This prevents the viscous, high-molecular-weight tar from accumulating on the tube walls and further coking, thus avoiding pipe blockage. The inner tubes are used for the high-temperature coking gas to undergo the coking reaction. During coking, the quenching medium between the outer wall of the quencher body and the side wall of the inner tubes can be water or water vapor, etc.

[0031] The high-power pulsed microwave quenching system significantly shortens the coking time compared to both traditional and non-pulsed microwave quenchers, increasing effective production time. This drastically reduces coking fuel gas consumption, lowering energy consumption and greenhouse gas emissions. Simultaneously, the pulsed microwave quenching system effectively removes and inhibits coking in the quencher, significantly reducing pressure drop and extending its operating cycle. This reduces carbon monoxide and carbon dioxide emissions during coking, resulting in significant environmental benefits. It also addresses the problem of tar easily forming and being difficult to remove in the quencher tubes, as seen in existing technologies. Compared to traditional quenchers, the inlet pressure drop of the pulsed microwave quencher is reduced by up to 92.50%, greatly extending its operating cycle, reducing the frequency of coking removal, and decreasing fuel consumption and greenhouse gas emissions. Furthermore, the yields of high-value pyrolysis products such as ethylene, propylene, butadiene, and trienes increase by 1.29%, 1.69%, 1.36%, and 1.42%, respectively, while heavy oil byproduct is reduced by 5.34%, making it a green and environmentally friendly technology.

[0032] A high-power pulsed microwave reactor, installed in combination with the main tubes of the quench cooler, can introduce high-power pulsed microwaves of a specific frequency into the quench cooler tubes through a dedicated waveguide. The dissociation effect of the high-power pulsed microwaves causes high-molecular-weight tar molecules to dissociate, generating smaller hydrocarbon products such as ethylene, propylene, and butene, increasing the yield of the target product and improving the economic efficiency of the unit. Simultaneously, the specific frequency microwaves reduce the dehydrogenation and condensation reactions of tar, minimizing the side reactions that generate coke.

[0033] The high-power pulsed microwave quench system can excite tar molecules in different raw materials by adjusting different operating frequencies, causing them to dissociate into small molecule olefins such as ethylene and propylene.

[0034] The high-power pulsed microwave quench system reduces coke formation and greenhouse gas emissions by dissociating tar molecules, and increases the operating cycle of the device. It solves the problems of short operating cycle, high energy consumption, low production efficiency and greenhouse gas emissions in traditional pyrolysis furnace quench systems, and is a green and environmentally friendly technology.

[0035] The auxiliary preheating of the high-power pulsed microwave quencher of this invention is indispensable. Only by maintaining the material at a temperature above 200°C can the high-power pulsed microwave quencher play its best role. The preferred temperature range is 400°C to 900°C.

[0036] For reliable and stable high-power pulsed microwave devices applicable to industry, the maximum single output power can only reach about 50KW. In practical applications, the rated power that can operate stably for a long period is only about 30KW. To extend the intensity of high-power pulsed microwave action, multiple microwave groups can be set up to work in parallel to achieve the ideal effect of tar dissociation.

[0037] Metallic conductors are commonly used as waveguide materials to prevent leakage of high-power pulsed microwaves. The function of a waveguide is to confine microwaves within a tube, preventing them from scattering in all directions and allowing them to propagate only along the axial direction. The dimensions of the waveguide and the microwave wavelength must satisfy a certain proportional relationship. If the long side of the waveguide is a, the short side is b, and the wavelength is λ, then a = 2b, and λ / 2 < a < λ.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] (1) The high-power pulsed microwave described in this invention has the characteristic of high instantaneous energy. The space charge region can achieve a very high peak power when located in a properly tuned resonant cavity. The power ranges from 0.1 to 40 GW. The high-power pulsed microwave is an S-band, X-band, or other band pulsed microwave source with a peak power of 0.1 W to 1000 kW, a repetition frequency of 1 kHz, a pulse width of 1 ns to 1000 ms, and a peak field strength of 0.1 kV / m to 1000 kV / m. The microwave power is introduced into the tube side of the microwave quencher through the magnetron, which quickly removes the original coke layer and suppresses the generation of new coke layer. This solves the problems of excessive energy dispersion, poor energy efficiency, and low decoking efficiency of ordinary microwaves.

[0040] (2) The online decoking process of the green and environmentally friendly quenching device described in this invention solves the problems of viscous high molecular weight tar continuously accumulating and blocking the inner tube wall of the pyrolysis quencher tube in the traditional technology by using high-power pulsed microwave to dissociate tar, resulting in short operation cycle of pyrolysis furnace, frequent coking, large emissions of greenhouse gases and harmful gases, short service life of pyrolysis furnace tube, high energy consumption and low production efficiency.

[0041] (3) Without altering the existing main equipment, this invention can reduce the generation of coke and greenhouse gas emissions by adding relevant equipment, reduce the number of times air burning and manual coke cleaning are required, improve the economic efficiency of the equipment, and comply with the low-carbon green chemical technology specifications. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the green and environmentally friendly rapid cooling device of the present invention;

[0043] Figure 2 This is a schematic diagram of the process flow for the online decoking process of the present invention;

[0044] Figure 3 This is a schematic diagram of the thermal decomposition and high-power pulsed microwave quenching process in Example 2;

[0045] Figure 4 This is a schematic diagram of the thermal decomposition and quenching process in Comparative Example 1.

[0046] Figure 5 This is a schematic diagram of the thermal decomposition and conventional microwave quenching processes in Comparative Example 2.

[0047] In the diagram: 1. Microwave quencher body; 2. Tube side; 3. Waveguide; 4. Cooling radiator; 5. Lower interface; 6. Shielding layer; 7. Upper interface; 8. Magnetron; 9. Microwave generator; 10. Energy storage device; 11. Explosion-proof control cabinet; 12. High-power pulsed microwave reactor. Detailed Implementation

[0048] The present invention will be further illustrated below by means of embodiments, but the present invention is not limited to these examples. These embodiments will provide a full understanding of the essence and scope of the present invention, and further illustrate the process characteristics described herein.

[0049] Example 1

[0050] like Figure 1 As shown, the green and environmentally friendly quenching device includes a microwave quencher body 1 and a microwave waveguide 3 connected and installed. The angle between the microwave quencher body 1 and the microwave waveguide 3 is 0° to 89° or 91° to 180° external angle, preferably 45° external angle. A cooler is installed on the outside of the high-power pulse microwave waveguide to reduce the high temperature of the pyrolysis furnace tube to a temperature that the magnetron can withstand.

[0051] The shielding layer of the pulsed microwave quenching device uses high-temperature modified polytetrafluoroethylene (PTFE), which undergoes a special ultrasonic microbubble filling process. The microbubbles in the modified PTFE enable it to simultaneously possess multiple properties: heat insulation, chemical isolation, and easy transmission of high-power microwave energy. This is one of the key components for implementing this invention. Its manufacturing process is as follows:

[0052] (1) Raw material preparation: PTFE fine resin, crushed and sieved;

[0053] (2) Clean the mold: Clean it with alcohol until there are no residues;

[0054] (3) Weigh the material, add it, and distribute the PTFE resin evenly on the mold;

[0055] (4) Pressing: Calculate the pressure gauge of the press, set the pressure gauge of the press, and press;

[0056] (5) Sintering: The semi-finished product is slowly placed into an ultrasonic sintering furnace and heated to approximately 300–400 degrees Celsius. Once the temperature is reached, the ultrasonic waves are turned on, and the released ultrasonic energy propagates at a uniform sound intensity of 0.01–0.5 W / cm². 2 The preferred concentration is 0.05–0.4 w / cm. 2 The ultrasonic frequency is 10kHz to 220kHz. After one hour of ultrasonic treatment, the temperature begins to drop until it reaches room temperature, thus completing the shaping process.

[0057] Comparative tests conducted over the same period showed that thicker ordinary PTFE exhibited poorer microwave penetration, while thinner ordinary PTFE showed poorer thermal insulation, failing to achieve a balance between penetration and thermal insulation. Modified PTFE, however, had no effect on microwave conduction and thus possessed both microwave penetration and thermal insulation properties simultaneously.

[0058] Example 2

[0059] like Figure 3 As shown, using Figure 3 The thermal pyrolysis and high-power pulsed microwave quenching process involves a pyrolysis reaction temperature of 850℃, naphtha as the pyrolysis feedstock, a feed rate of 5 kg / h, a dilution ratio of 0.5, and a residence time of 0.26 s. The reactants pass through the feeding system and the pyrolysis furnace heating system before entering the pulsed microwave quenching device. Liquid phase products are collected from the product separation outlet, and samples are taken from the vent outlet to analyze the composition of the pyrolysis gas after the reaction. The high-power pulsed microwave is an S-band pulsed microwave source with a peak power of 500 kW, a repetition frequency of 1 kHz, a pulse width of 80 ns, and a peak field strength of 100 kV / m. After 6 hours of system operation, the inlet pressure dropped to 10 kPa. The inlet pressure in this embodiment was significantly lower than that of the blank group in Comparative Example 1 by 87.5%, which will greatly increase the operating cycle of the quench cooler. The feeding was stopped, and the temperature of the coking steam was raised to 800°C. Air was mixed in and maintained at 800°C. The oxygen content of the coking gas at the outlet of the quench cooler was detected by the coking controller. At first, the carbon monoxide and carbon dioxide content increased slightly, reaching 5%, but decreased rapidly after 0.1 hours. The oxygen content continued to rise until it reached a level comparable to that of air. At this point, the coking operation was completed, and the coking time was 0.2 hours, which was significantly reduced compared to the coking time of the blank group in Comparative Example 1.

[0060] Compared with Comparative Example 1, the high-power pulsed microwave quenching process of the present invention significantly reduces the charring time, carbon monoxide emissions and carbon dioxide emissions compared with the traditional quenching process, and is superior to the non-pulsed microwave quenching process.

[0061] Example 3

[0062] To enhance the dissociation effect of microwaves, in such cases... Figure 3Based on the above, three pulsed microwave quenchers were connected in parallel as shown in the figure. Using the same raw materials and process conditions as in Example 2, experiments were conducted for evaluation. The high-power pulsed microwave was an S-band pulsed microwave source with a peak power of 500 kW, a repetition frequency of 1 kHz, a pulse width of 80 ns, and a peak field strength of 100 kV / m. After the system ran for 6 hours, the inlet pressure dropped to 6 kPa, which was a significant decrease of 92.5% compared with the blank group in Comparative Example 1. This will greatly increase the operating cycle of the quencher. Feeding was stopped, and the temperature of the coking steam was raised to 800°C. Air was then mixed in and maintained at 800°C. The oxygen content of the coking gas at the outlet of the quencher was detected by the coking controller. The experimental results are as follows: Initially, the carbon monoxide and carbon dioxide contents increased slightly, reaching 4%, but decreased rapidly after 0.06 hours. The oxygen content continued to rise until it reached a level comparable to that of the air. At this point, the coking operation was completed, and the coking time was 0.15 hours, which was significantly reduced compared with the coking time of the blank group in Comparative Example 1.

[0063] This embodiment illustrates that parallel connection of multiple high-power pulsed microwave rapid cooling processes reduces the charring time and emissions of carbon monoxide and carbon dioxide compared to a single pulsed microwave process.

[0064] Comparative Example 1

[0065] As a blank group, such as Figure 4 As shown, using Figure 4 The traditional thermal cracking and quenching process involves a cracking reaction temperature of 850℃, naphtha as the feedstock, a feed rate of 5 kg / h, a dilution ratio of 0.5, and a residence time of 0.26 s. The reactants pass through the feeding system and the cracking furnace heating system before entering the conventional quenching unit. The conventional quencher operates for 6 hours. Liquid products are collected from the product separation outlet, and samples are taken from the vent outlet to analyze the composition of the cracked gas after the reaction. When the inlet pressure drop reaches the upper limit of 80 kPa, feeding is stopped, and the coking steam temperature is raised to 800℃. Air is then introduced and maintained at 800℃. The oxygen content of the coking gas at the quencher outlet is monitored by the coking controller. Initially, the carbon monoxide and carbon dioxide contents are high, reaching the instrument detection upper limit of 25% for 1.5 hours. As the coking process continues, the carbon monoxide and carbon dioxide contents gradually decrease, while the oxygen content continues to rise until it reaches a level comparable to that of air. At this point, the coking operation is complete, taking 2 hours. During the coking process, the temperature indication of the thermocouple is continuously monitored and must not exceed the upper temperature limit of 1100℃ for the 2520 material. It is generally set to within 1000℃. Once it approaches this temperature, the amount of coking air flowing in is reduced to control the coking reaction.

[0066] Comparative Example 2

[0067] The process employs thermal pyrolysis and non-pulsed microwave quenching, such as Figure 5 As shown, using Figure 5The process involves thermal pyrolysis and non-pulsed microwave quenching. The pyrolysis reaction temperature is 850℃, the feedstock is naphtha, the feed rate is 5 kg / h, the dilution ratio is 0.5, and the residence time is 0.26 s. The reactants pass through the feeding system and the pyrolysis furnace heating system before entering the non-pulsed microwave quenching unit. Liquid products are collected from the product separation outlet, and the composition of the pyrolysis gas after the reaction is analyzed by sampling from the vent outlet. The high-power pulsed microwave source is an S-band pulsed microwave source with a peak power of 500 kW, a repetition frequency of 1 kHz, a pulse width of 80 ns, and a peak field strength of 100 kV / m. After 6 hours of system operation, the inlet pressure dropped to 60 kPa, a slight decrease of 25% compared to the blank group (Comparative Example 1). Feeding was stopped, and the coking steam temperature was raised to 800°C. Air was then introduced and maintained at 800°C. The oxygen content of the coking gas at the quencher outlet was monitored by the coking controller. Initially, the carbon monoxide and carbon dioxide contents increased, reaching 20%, but decreased rapidly after 0.5 hours. The oxygen content continued to rise until it reached a level comparable to that of air. At this point, the coking operation was complete, with a coking time of 1 hour, which was less than that of the blank group (Comparative Example 1). This indicates that the non-pulse microwave quenching process significantly reduces the coking time compared to the traditional quenching process, and also emits less carbon monoxide and carbon dioxide.

[0068] After the above-mentioned rapid cooling and pyrolysis were performed on Examples 2-3 and Comparative Examples 1-2, the pyrolysis products were analyzed and detected. The detection results are shown in Table 1.

[0069] Table 1. Detection results of pyrolysis products

[0070] hydrogen 0.84 0.85 0.86 0.86 2.10％ ethylene 30.20 30.36 30.55 30.59 1.29％ propylene 15.42 15.50 15.63 15.68 1.69％ butadiene 5.87 5.89 5.93 5.95 1.36％ heavy oil 10.30 10.05 9.78 9.75 -5.34％ Triene yield 51.49 51.75 52.11 52.22 1.42％

[0071] As can be seen from the above, compared with the traditional process, the pulse microwave quenching process of the present invention significantly increases the yield of value-added products. The yield of high value-added products is ranked as follows: Example 3 > Example 2 > Comparative Example 2 > Comparative Example 1. The yield of low-value heavy oil is ranked as follows: Comparative Example 1 > Comparative Example 2 > Example 2 > Example 3. Compared with the traditional process (Comparative Example 1), Example 2 (high-power pulse microwave quenching system) and Example 3 (parallel high-power pulse microwave quenching system) have significant advantages in the yield of high value-added products, which will help improve the economic efficiency of the equipment.

[0072] In summary, the high-power pulsed microwave quenching system significantly shortens the coking time compared to both traditional and non-pulsed microwave quenchers, increasing effective production time. This will substantially reduce coking fuel gas consumption, lower energy consumption, and reduce greenhouse gas emissions from the fuel gas. Simultaneously, the pulsed microwave quenching system can remove and inhibit coking in the quencher, significantly reducing pressure drop and extending the quencher's operating cycle, thus reducing carbon monoxide and carbon dioxide emissions during the coking process, resulting in significant environmental benefits. Furthermore, the pulsed microwave quenching system can effectively increase the yield of high-value-added products while reducing low-value products, demonstrating good economic benefits.

[0073] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An online decoking process for a green and environmentally friendly rapid cooling device, characterized in that: It includes the steps of rapidly cooling high-temperature pyrolysis gas using a pyrolysis quenching process, and the steps of performing microwave pulse decoking on the quencher according to an online decoking process. Based on the thermal decomposition temperature rise to the transverse temperature, high-power pulsed microwaves are used to utilize the reverse dissociation effect of microwaves to reverse dissociate the viscous high molecular weight tar generated on the inner wall of the quencher tube into small molecule ethylene, propylene, butadiene, high value-added gaseous and liquid products. These products flow out of the tube along with the gas and liquid phase mixture, reducing and suppressing the formation of high molecular weight tar, while also reducing the side reaction of high molecular weight tar condensing into coke. High-power pulsed microwaves have a power range of 0.1-40GW. They are S-band, X-band, or other band pulsed microwave sources with a peak power of 0.1W to 1000kW, a repetition frequency of 1kHz, a pulse width of 1ns to 1000ms, and a peak field strength of 0.1kV / m to 1000kV / m.

2. A green and environmentally friendly rapid cooling device used in the online decoking process of claim 1, characterized in that: It includes a microwave quencher body (1) and a high-power pulsed microwave reactor (12); the high-power pulsed microwave reactor (12) includes a waveguide (3), a cooling radiator (4), a magnetron (8), a microwave generator (9), and an energy storage device (10); the microwave quencher body (1) is connected to the waveguide (3) through a tube (2), the waveguide (3) is connected to the magnetron (8), the magnetron (8) is connected to the microwave generator (9), and the microwave generator (9) is connected to the energy storage device (10); an upper interface (7) and a lower interface (5) are provided at the connection between the waveguide (3) and the magnetron (8), a shielding layer (6) is provided between the upper interface (7) and the lower interface (5), and a cooling radiator (4) is provided on the waveguide (3).

3. The green and environmentally friendly rapid cooling device according to claim 2, characterized in that: The microwave generator (9) is equipped with an explosion-proof control cabinet (11).

4. The green and environmentally friendly rapid cooling device according to claim 2, characterized in that: The cavity of the waveguide (3) is an inner conical cavity structure, which is horn-shaped.

5. The green and environmentally friendly rapid cooling device according to claim 4, characterized in that: The cross-section of the waveguide (3) is cylindrical, conical, square or triangular, and its end face is flat or curved.

6. The green and environmentally friendly rapid cooling device according to claim 2, characterized in that: The waveguide (3) is at an angle of 0°~89° or 91°~180° to the tube side (2).

7. The green and environmentally friendly rapid cooling device according to claim 2, characterized in that: The magnetron (8) is a pulsed microwave magnetron with a metal-dielectric cathode.

8. The green and environmentally friendly rapid cooling device according to claim 2, characterized in that: Multiple sets of high-power pulsed microwave reactors (12) are installed on the microwave quencher body (1).

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