A hot gas direct cracking system with coke removal and coke monitoring

Abstract

The present invention discloses a hot-carrying gas direct cracking system with coke removal and coke formation monitoring, which comprises: a combustion reaction section, a cracking pipe section, a rapid cooling section and a gas-liquid and coke separation section connected in sequence along the direction of the hot-carrying gas, the combustion reaction section comprises a burner, the burner is provided with a plurality of combustion gas inlets and at least one ignition device, the burner has a combustion chamber, and the plurality of combustion gas inlets and the ignition device extend to the combustion chamber; the cracking pipe section is provided with a plurality of decoking gas pipes, a decoking gas outlet nozzle, a resistance monitoring unit and a temperature detection unit along the pipeline direction; the outer side of the burner is provided with a cracking furnace raw material waste heat device and a cracking furnace raw material delivery pipeline arranged in a spiral manner, and the cracking furnace raw material delivery pipeline extends to the inner cavity of the cracking pipe section through the cracking furnace raw material inlet pipe. The present invention solves the problems of real-time monitoring of coking, real-time decoking, and fixed-point coke removal.

Description

Technical Field

[0001] The invention relates to the field of olefin production, and in particular to a hot-carrying gas direct cracking system with coke removal and coking monitoring. Background Art

[0002] Light olefins such as ethylene and propylene are the basic raw materials of the petrochemical industry, and the production capacity of light olefins is one of the important indicators of a country's petrochemical development level. Although steam cracking is the most widely used method for producing light olefins and has maximized the optimization of olefin yields, the current steam cracking process has high comprehensive energy consumption, large steam consumption, and long residence time. In addition, since the cracking furnace tubes are indirectly heated by boilers, the fuel consumption and carbon emissions are large. Therefore, it is feasible and practical to study new naphtha cracking processes based on the current production process. The cracking furnace is a high-energy-consuming equipment in the ethylene plant. Studies have shown that the total energy consumption of the steam cracking furnace is high. The efficiency is about 43.4%, and the radiant combustion process The loss is the greatest. Therefore, the reasonable implementation of thermal management for energy-consuming devices such as ethylene will be a focus issue. Although steam cracking has been put into operation in industry for many years, the heating method of indirect heating of cracking furnace tubes by boilers has not changed, and the pipe blockage phenomenon during operation has not been fundamentally improved. Replacing the furnace tubes will cause huge economic losses. Therefore, the development of high Olefin cracking technology with high efficiency, low carbon emissions and long operating cycle has great industrial application prospects.

[0003] Steam cracking is the most commonly used method for industrial production of ethylene. After the raw materials and steam of the cracking furnace are mixed, they are passed into the high-temperature cracking furnace radiation tube, and a cracking reaction occurs inside the tube to produce hydrocarbon products such as ethylene and propylene. While the hydrocarbon undergoes steam cracking reaction in the radiation section of the cracking furnace, the cracking reaction will be accompanied by secondary reactions. Coke will be deposited on the tube wall of the radiation section furnace tube. The continuous deposition of coke powder in the furnace tube eventually leads to coking. The coking phenomenon will increase the thermal resistance of the tube wall and reduce the heat transfer coefficient of the tube wall. In order to reach the reaction temperature, the temperature of the furnace tube wall needs to be increased, resulting in excessively high local temperature of the furnace tube wall, which will reduce the life of the furnace tube and increase the energy consumption during the reaction. The continuous deposition of the coke layer will cause the inner diameter of the furnace tube to continue to shrink, increase the pressure drop of the raw material fluid in the furnace tube, reduce the amount of cracking raw materials participating in the reaction, and reduce the yield of olefins. As the degree of coking continues to increase, it will eventually even block the furnace tube, causing safety problems. Therefore, when the coking limit required by a certain process is reached, the radiation furnace tubes of the cracking furnace must be decoked; at the same time, the accumulation of coke on the inner wall of the furnace tube will cause carburization of the inner wall of the furnace tube, damage the high-temperature alloy, and reduce the service life of the furnace tube.

[0004] The decoking process requires regular shutdown of the furnace for coking. The decoking gas generally enters from the cracking inlet and cannot directly act on the coking area. It is impossible to decoke when there is partial coking during the operation process. The coking location cannot be monitored in real time, etc.

[0005] Therefore existing technology is in urgent need of improvement and development. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a hot gas direct cracking system with decoking and coking monitoring, which can perform decoking operations by introducing decoking gas into the decoking gas pipe of the corresponding furnace tube.

[0007] To achieve the above object, the present invention can be carried out by adopting the following technical solutions:

[0008] A hot-carrying gas direct cracking system comprises: a combustion reaction section, a cracking pipe section, a rapid cooling section and a gas-liquid and coke separation section which are sequentially connected along the traveling direction of the hot-carrying gas.

[0009] The combustion reaction section comprises a burner, the burner is provided with a plurality of combustion gas inlets and at least one ignition device, the burner has a combustion chamber, the plurality of the combustion gas inlets and the ignition device extend to the combustion chamber;

[0010] The cracking pipe section is provided with a plurality of decoking gas pipes, decoking gas outlet nozzles, resistance monitoring units and temperature detection units along the pipeline direction;

[0011] The outer side of the burner is provided with a cracking furnace raw material waste heat device and a cracking furnace raw material delivery pipeline arranged in a spiral manner, the cracking furnace raw material delivery pipeline extends to the inner cavity of the cracking pipe section through a cracking furnace raw material inlet pipe, the end of the cracking furnace raw material inlet pipe is provided with a cracking furnace raw material atomizing head, and the cracking furnace raw material waste heat device is used to preheat the cracking furnace raw material delivery pipeline;

[0012] Among them, gas fuel and combustion-supporting oxygen enter the burner from multiple combustion gas inlets respectively, are ignited by the ignition device and burn in the combustion chamber, and high-temperature flue gas is generated after combustion and enters the cracking tube section. At the same time, the cracking furnace raw material is preheated and heated through the cracking furnace raw material conveying pipeline, and then atomized by the cracking furnace raw material atomizing head and directly cracked in the cracking tube section. During this period, the resistance monitoring unit obtains real-time relevant data on the amount of coking in the tube by monitoring the change of resistance value between each section. The temperature detection unit detects the coking thickness during normal operation and the tube wall temperature during decoking through the temperature change on the surface of the furnace tube. According to the data fed back by the resistance monitoring unit and the temperature detection unit, the decoking gas is introduced into the decoking gas pipe to remove the coking in the tube of the cracking tube section. The cracked gas enters the rapid cooling section for rapid cooling, and then enters the gas-liquid and coke separation section for separation.

[0013] In the hot-carrying gas direct cracking system as described above, further, the outlet of the gas-liquid and coke separation section is provided with a plurality of gas sensors, and the plurality of gas sensors are used to detect the content of a specific gas to obtain the final decoking effect.

[0014] The hot-carrying gas direct cracking system as described above, further, has a power section disposed on the upper portion of the gas-liquid and coke separation section, and a plurality of gas sensors are disposed at the outlet of the power section, and the plurality of gas sensors are used to detect specific gas content to obtain a final decoking effect.

[0015] In the hot carrier gas direct cracking system as described above, further, a rectifier is provided at the gas inlet of the burner, and the multiple combustion gas inlets include a first combustion gas inlet, a second combustion gas inlet and a third combustion gas inlet, the first combustion gas inlet is arranged at the axis center of the rectifier and extends to the combustion chamber through the rectifier, the second combustion gas inlet is arranged obliquely to the first combustion gas inlet, and the third combustion gas inlet is arranged perpendicular to the first combustion gas inlet and extends to the inner cavity of the rectifier.

[0016] The hot carrier gas direct cracking system as described above, further, the burner has a burner inner wall, the enclosed space surrounded by the burner inner wall is the combustion chamber, the outer layer of the burner inner wall is provided with burner inner insulation, the outer layer of the burner inner insulation is provided with a burner outer surface, and the outer layer of the burner outer surface is provided with the cracking furnace raw material waste heat device.

[0017] In the hot-carrying gas direct cracking system as described above, further, the decoking gas pipe is provided with a decoking gas valve at a portion outside the cracking pipe section, and the decoking gas pipe is provided with a decoking gas outlet nozzle at a portion inside the cracking pipe section.

[0018] In the hot-carrying gas direct cracking system as described above, further, the outer layer of the cracking tube section is provided with furnace tube outer insulation.

[0019] The hot gas direct cracking system as described above, further, the upper part of the gas-liquid and coke separation section is also provided with a light hydrocarbon separation system connected to the gas phase, and the lower part of the gas-liquid and coke separation section is also provided with a liquid phase multilayer distillation system and / or a liquid phase oil decoking system.

[0020] In the hot-carrier gas direct cracking system as described above, further, the burner is also provided with a cracking furnace raw material inlet.

[0021] In the hot-carrying gas direct cracking system as described above, further, the cracking pipe sections are arranged horizontally, inclined, or in one or more layers of spiral bending arrangements.

[0022] In the hot carrier gas direct cracking system as described above, further, the decoking gas can be a mixed gas of oxygen and / or water vapor and / or carbon dioxide and / or inorganic salt inhibitors.

[0023] In the hot carrier gas direct cracking system as described above, further, the cracking furnace raw material inlet is provided with an atomizing device.

[0024] The hot carrier gas direct cracking system as described above, further, the cracking system can be in a high pressure state or a normal pressure state.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. A plurality of resistance monitoring units and temperature detection units are arranged on the outer tube wall of the cracking tube section of the hot carrier gas direct cracking system according to the embodiment of the present invention. The base data of real-time monitoring of coking of each section of the furnace tube is measured during the initial operation after the system is newly built or shut down for overhaul and the furnace tube is decoked. The base data is compared with the real-time data of coking of each section of the furnace tube when the system is running, so as to find the position of the coking section of the furnace tube.

[0027] 2. The hot carrier gas direct cracking system of the embodiment of the present invention is provided with a decoking gas valve, which can be used for decoking without stopping the furnace. By opening the corresponding decoking gas valve, the decoking gas is directly introduced into the corresponding furnace tube for decoking operation. The oxygen in the decoking gas reacts with coke to produce carbon monoxide and carbon dioxide. The carbon monoxide, carbon dioxide and water vapor produced in the decoking process have a certain effect on cracking, and can also reduce the amount of carbon dioxide and water vapor at the raw material inlet of the corresponding cracking furnace, thereby increasing the continuous operation time of the equipment, greatly reducing product costs, improving equipment operation efficiency, and reducing energy consumption during the shutdown and restart process.

[0028] 3. The hot carrier gas direct cracking system of the embodiment of the present invention is provided with a decoking gas valve. When the furnace is shut down for decoking, the decoking gas can be directly introduced into the corresponding furnace tube by opening the corresponding decoking gas valve, so that the decoking gas can directly act on the coke, which can reduce the oxidation of the furnace tube and the time required for the decoking process. At the same time, by comparing the real-time data of coking in each section of the furnace tube during operation, the decoking gas entry position can be adjusted in time to effectively remove the coke.

[0029] 4. The hot carrier gas direct cracking system of the embodiment of the present invention is provided with a decoking gas valve. By opening the decoking gas valve at a suitable position and adjusting a suitable small flow rate as a permanent decoking gas reserve, part of the coke produced by the secondary reaction accompanying the cracking reaction can be offset, thereby slowing down the formation of coke, extending the normal operation time of the equipment, reducing the product operation cost, and improving the equipment operation efficiency.

[0030] 5. In the hot carrier gas direct cracking system of the embodiment of the present invention, the hot carrier gas generated by combustion is directly cracked to reduce the energy consumption and emissions of the device. In addition, direct heat exchange has no heat transfer resistance, and the heat exchange efficiency is much higher than that of indirect heat exchange, which can greatly reduce the energy consumption and emissions of the device and improve Efficiency, increasing cracking temperature and reducing reaction residence time, so as to achieve the purpose of increasing olefin production and improving efficiency, with the advantages of easy operation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 Schematic diagram of the structure of a hot carrier gas direct cracking system according to an embodiment of the present invention.

[0033] Wherein: 1. Combustion reaction section; 2. Cracking pipe section; 3. Rapid cooling section; 4. Gas-liquid and coke separation section; 5. Power section; 10. First combustion gas inlet; 11. Second combustion gas inlet; 12. Ignition device; 13. Third combustion gas inlet; 14. Rectifier; 15. Inner wall of burner; 16. Inner insulation of burner; 17. Outer surface of burner; 18. Combustion chamber; 19. Combustion reaction section outlet; 20. Cracking furnace raw material waste heat device; 21. Cracking furnace raw material inlet pipe; 22. Cracking furnace raw material atomizing head; 23. Decoking gas; 24. Decoking gas valve; 25. Decoking gas pipe; 26. Decoking gas outlet nozzle; 27. Resistance monitoring unit; 28. Temperature detection unit; 29. ​​External insulation of furnace tube; 30. Cracking furnace raw material inlet; 40. Gas product outlet; 50. Non-gas product outlet. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] Example:

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations of the embodiments of the present invention are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In the description of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise clearly defined. In addition, unless otherwise clearly defined and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] See also Figure 1 , Figure 1FIG. 1 is a schematic diagram of the structure of an embodiment of a hot carrier gas direct cracking system with coke cleaning and coke monitoring according to the present invention. Figure 1 As shown, the hot gas direct cracking system with coke removal and coke formation monitoring comprises: a combustion reaction section 1, a cracking pipe section 2, a rapid cooling section 3 and a gas-liquid and coke separation section 4 which are sequentially connected along the traveling direction of the hot gas, the combustion reaction section 1 comprises a burner, the burner is provided with a plurality of combustion gas inlets and at least one ignition device 12, the burner has a combustion chamber 18, and the plurality of combustion gas inlets and the ignition device 12 extend to the combustion chamber 18; the cracking pipe section 2 is provided with a plurality of decoking gas pipes 25, a resistance monitoring unit 27 and a temperature detection unit 28 along the pipeline direction; the outer side of the burner is provided with a cracking furnace raw material waste heat device 20 and a cracking furnace raw material conveying pipeline arranged in a spiral manner, the cracking furnace raw material conveying pipeline extends to the inner cavity of the cracking pipe section 2 through a cracking furnace raw material inlet pipe 21, the end of the cracking furnace raw material inlet pipe 21 is provided with a cracking furnace raw material atomizing head 22, and the cracking furnace raw material waste heat device 20 is used to preheat the cracking furnace raw material conveying pipeline.

[0041] Specifically, gas fuel and combustion-supporting oxygen enter the burner from the multiple combustion gas inlets respectively, are ignited by the ignition device 12 and burn in the combustion chamber 18, and high-temperature flue gas is generated after combustion and enters the cracking tube section 2. At the same time, the cracking furnace raw material is preheated and heated by the cracking furnace raw material conveying pipeline, and then atomized by the cracking furnace raw material atomizing head 22 and directly cracked in the cracking tube section 2. During this period, the resistance monitoring unit 27 obtains real-time relevant data on the amount of coking in the tube by monitoring the slight changes in the resistance values ​​between each section. The temperature detection unit 28 detects the coking thickness during normal operation and the tube wall temperature during decoking by the temperature changes on the furnace tube surface. According to the data fed back by the resistance monitoring unit 27 and the temperature detection unit 28, the decoking gas pipe 25 introduces the decoking gas 23 to remove the coking in the cracking tube section 2. The cracked gas enters the rapid cooling section 3 for rapid cooling, and then enters the gas-liquid and coke separation section 4 for separation.

[0042] The hot-carrier gas direct cracking system with coke removal and coke monitoring of the embodiment of the present invention provides a technical solution to the coke removal and coke monitoring problems of the cracking system. By setting a cracking furnace raw material waste heat device 20, the cracking furnace raw material conveying pipeline is preheated, so that the cracking tube section 2 does not need to be heated or does not need to be in direct contact with the flame. In this way, a plurality of decoking gas pipes 25, a resistance monitoring unit 27 and a temperature detection unit 28 can be set on the outer tube wall of the cracking tube section 2 to monitor the real-time data of coking of each section of the furnace tube of the cracking tube section 2. Then, the monitored real-time data of coking is compared with the benchmark data of real-time monitoring of coking of each section of the furnace tube measured in the first operation after the equipment is newly built or the furnace is shut down for overhaul and the furnace tube is decoked. The position of the coking section furnace tube can be found in time, and then the decoking operation is performed by introducing the decoking gas 23 into the decoking gas pipe 25 of the corresponding furnace tube. In addition, the oxygen-containing gas in the decoking gas 23 reacts with coke to produce carbon monoxide and / or carbon dioxide. The carbon monoxide, carbon dioxide and water vapor produced or introduced during the decoking process have a certain effect on cracking. At the same time, reducing the amount of carbon dioxide and water vapor at the corresponding cracking furnace raw material inlet 30 can increase the continuous operation time of the equipment, greatly reduce product costs, improve equipment operation efficiency, and reduce energy consumption during shutdown and restart. In addition, direct cracking of the hot carrier gas produced by combustion can reduce the energy consumption and emissions of the device. In addition, direct heat exchange has no heat transfer resistance, and the heat exchange efficiency is much higher than indirect heat exchange, which can greatly reduce the energy consumption and emissions of the device and improve Efficiency, increasing cracking temperature and reducing reaction residence time, so as to achieve the purpose of increasing olefin production and improving efficiency, with the advantages of easy operation and low cost.

[0043] In the above technical solution, the burner can be a combustion system including pure oxygen and oxygen-enriched conditions, which can be arranged horizontally, upward, downward or at any angle. The burner has a burner inner wall 15, and the closed space surrounded by the burner inner wall 15 is the combustion chamber 18. The outer layer of the burner inner wall 15 is provided with a burner inner insulation 16, and the outer layer of the burner inner insulation 16 is provided with a burner outer surface 17, and the outer layer of the burner outer surface 17 is provided with the cracking furnace raw material waste heat device 20.

[0044] The cracking tube section 2 is provided with a number of resistance monitoring units 27 and temperature detection units 28 along the pipeline direction, wherein the resistance monitoring unit 27 obtains the real-time related data of the coking amount in the tube by monitoring the slight changes in the resistance value between each section, and the change in the resistance value includes the change in the current value under the constant voltage source, or the small signal of the change in the voltage value under the constant current source, and the change in the resistance of the interval section is detected to represent the change in the coking amount of the interval section. The temperature detection unit 28 is mainly based on thermocouples, and can include temperature sensors such as thermocouples, thermal resistors or thermal semiconductors. The temperature detection unit 28 can detect the approximate coking thickness during normal operation and the tube wall temperature during decoking through the temperature change on the surface of the furnace tube, and it detects the temperature change during the stable operation under the same inlet conditions or the same outlet conditions to represent the coking thickness at the point. When in use, the resistance and temperature benchmark data of the real-time monitoring of the coking of each section of the furnace tube after the equipment is newly built or the furnace is shut down for overhaul and the furnace tube is decoked are compared with the real-time resistance and temperature data of the coking of each section of the furnace tube during operation, so as to find the position of the coking section furnace tube. The resistance data needs to be coupled with the temperature to obtain the corresponding resistance value curve under each operating temperature condition during the initial operation, and then the coking area is obtained by comparing the calculated reference resistance value corresponding to the temperature of each detection point during real-time operation with the actual resistance value detected in each section. At the same time, the relative coking area can also be obtained by the temperature change of each detection point. When the hot carrier gas direct cracking system of the embodiment of the present invention monitors the coking state, the resistance signal can be collected for monitoring by the resistance monitoring unit 27, the temperature signal can be collected for monitoring by the temperature detection unit 28, or the resistance monitoring unit 27 and the temperature detection unit 28 can be used together for monitoring.

[0045] On the basis of the above embodiment, as an optional embodiment, a rectifier 14 is further provided at the gas inlet of the burner, and the multiple combustion gas inlets include a first combustion gas inlet 10, a second combustion gas inlet 11 and a third combustion gas inlet 13. The first combustion gas inlet 10 is arranged at the axis of the rectifier 14 and extends to the combustion chamber 18 through the rectifier 14. The second combustion gas inlet 11 is arranged obliquely to the first combustion gas inlet 10. The third combustion gas inlet 13 is arranged perpendicular to the first combustion gas inlet 10 and extends to the inner cavity of the rectifier 14. The combustion gas includes fuel gas and oxygen-containing gas such as air and oxygen. One or two of the first combustion gas inlet 10, the second combustion gas inlet 11 and the third combustion gas inlet 13 are used to feed fuel gas, and the remaining combustion gas inlets are used to feed combustion-supporting gas. For example, the first combustion gas inlet 10 and the third combustion gas inlet 13 are generally fed with the same gas, or different gases can be fed.

[0046] By setting the rectifier 14, the present embodiment can make the gas distribution in the combustion chamber 18 more uniform and make the combustion more complete. When in use, the gas fuel and the combustion-supporting oxygen enter the burner from the first combustion gas inlet 10, the second combustion gas inlet 11 and the third combustion gas inlet 13 respectively, and are ignited by the ignition device 12 to burn in the combustion chamber 18, and at the same time, the ratio of the gas fuel and the combustion-supporting oxygen is adjusted so that the combustion product has no oxygen or contains less oxygen. After combustion, the high-temperature flue gas generated enters the inlet of the cracking pipe section 2 through the combustion reaction section outlet 19. The cracking furnace raw material enters the pipeline from the cracking furnace raw material inlet 30 and is preheated and heated by the cracking furnace raw material waste heat device 20, and the raw material waste heat device is wrapped with insulation material. In another embodiment, the cracking furnace raw material can also be preheated by an external heat exchanger or preheated by an external heat exchanger and the cracking furnace raw material waste heat device 20, and then passed to the cracking furnace raw material inlet pipe 21, and then atomized by the cracking furnace raw material atomization head 22 to the cracking pipe section 2 for direct cracking. The cracked gas enters the rapid cooling and cooling section 3 for rapid cooling and cooling, and then enters the gas-liquid and coke separation section 4 for separation. Furthermore, the lower part of the gas-liquid and coke separation section 4 can also be connected to the multi-layer distillation system of the liquid phase or the decoking system of the liquid phase oil, or it can be connected to the decoking system of the liquid phase oil and then introduced into the raw material inlet 30 of the cracking furnace; the upper part of the gas-liquid and coke separation section 4 can also be connected to the light hydrocarbon separation system (cracked gas deep cold separation system), or it can be connected to the power section 5. Furthermore, the outlet of the power section 5 is also provided with a variety of gas sensors, including gas sensors such as carbon monoxide, carbon dioxide, and oxygen, and a variety of the gas sensors are used to detect the content of specific gases, and the final decoking effect is obtained by detecting the content of carbon dioxide and oxygen. In addition, the hot carrier gas direct cracking system of this embodiment can also control the pressure of each inlet, including the pressure of the inlet of the cracking furnace raw material, gas fuel and combustion-supporting oxygen, and the decoking gas 23, so that the system is kept in positive pressure operation.

[0047] In another embodiment, when in use, the gas fuel and the combustion-supporting oxygen enter the burner from the first combustion gas inlet 10, the second combustion gas inlet 11 and the third combustion gas inlet 13 respectively, and are ignited by the ignition device 12 to burn in the combustion chamber 18, and at the same time, the ratio of the gas fuel and the combustion-supporting oxygen is adjusted so that the product after combustion has more oxygen. After combustion, the high-temperature flue gas generated enters the inlet of the cracking pipe section 2 through the combustion reaction section outlet 19. At the same time, the raw material of the cracking furnace stops being introduced. The cracked gas enters the rapid cooling and cooling section 3 for rapid cooling and cooling, and then enters the gas-liquid and coke separation section 4 for separation.

[0048] As an optional embodiment, in certain embodiments, the decoking gas pipe 25 is provided with a decoking gas valve 24 at a portion outside the cracking pipe section 2 , and the decoking gas pipe 25 is provided with a decoking gas outlet nozzle 26 at a portion inside the cracking pipe section 2 .

[0049] Specifically, in this embodiment, by setting the decoking gas valve 24, the furnace can be decoked without stopping. The specific operation is as follows: open the corresponding decoking gas valve 24 to adjust the appropriate flow rate at each point, and pass the decoking gas 23. The decoking gas 23 enters the decoking gas pipe 25 and then enters the decoking gas outlet nozzle 26. Among them, the decoking gas pipe valve is as close as possible to the decoking gas outlet nozzle 26. The decoking gas outlet nozzle 26 is conducive to allowing the decoking gas 23 to adhere to the wall and effectively act on the coke surface on the inner surface of the furnace tube. At the same time, the high-pressure gas of the decoking gas outlet nozzle 26 can also effectively blow away the blocked coke. Preferably, the decoking gas 23 can also be heated by an external heat exchanger before entering the furnace tube, so that it can react immediately after entering the furnace tube, thereby reducing the reaction time and better removing the coke on the inner surface of the furnace tube. Exemplarily, the decoking gas 23 can be a mixed gas of oxygen and / or water vapor and / or carbon dioxide and / or (inorganic salt) inhibitor. The oxygen-containing gas in the decoking gas 23 reacts with coke to produce carbon monoxide and carbon dioxide. The carbon monoxide, carbon dioxide and water vapor produced during the decoking process have a certain effect on cracking, and can also reduce the amount of carbon dioxide and water vapor at the corresponding cracking furnace raw material inlet 30, increase the continuous operation time of the equipment, greatly reduce product costs, and reduce the energy consumption of the shutdown and restart process. In addition, when the furnace is shut down for decoking, the corresponding decoking gas valve 24 can be opened to directly pass the decoking gas 23 into the corresponding furnace pipe, so that the decoking gas 23 directly acts on the coke, which can reduce the oxidation of the furnace pipe and reduce the time required for the shutdown and decoking process. At the same time, by comparing the real-time data of coking in each section of the furnace pipe during operation, the entry position of the decoking gas 23 can be adjusted in time, and the coke can be effectively cleared.

[0050] Furthermore, the outer layer of the cracking tube section 2 is provided with an insulation material furnace tube outer insulation 29, which can reduce the heat dissipation loss of heat exchange with the burner outer surface 17 and improve the cracking gas inlet temperature. In addition, the furnace tube of the cracking tube section 2 can be spiral or spiral downward, or it can be as shown in FIG. Figure 1 The horizontal arrangement shown can also be arranged with the outlet downward, or can be arranged downwardly inclined. In addition, the hot carrier gas direct cracking system of the embodiment of the present invention can be operated under high pressure conditions or under normal pressure conditions.

[0051] On the basis of the above embodiment, as an optional embodiment, the decoking gas valve 24 can also be kept open during the stable operation of the hot gas direct cracking system to maintain the decoking effect. The specific operation is as follows: open the decoking gas valve 24 at a suitable position, and adjust a suitable small flow rate as a permanent decoking gas 23 to offset part of the coke produced by the secondary reaction in the cracking reaction, and also keep the decoking gas outlet nozzle 26 unobstructed. The flow rate of each section of the retained gas can be different according to the coking situation. Generally, there are more in the middle section and less in the beginning section. At the same time, the flow rate of the decoking gas 23 implemented in each section can be adjusted by the data monitored by the resistance monitoring unit 27 and the temperature detection unit 28 to keep the tube furnace unobstructed for a long time. Such operation can maintain the furnace without stopping to clean coke for a long time. In this embodiment, the decoking gas valve 24 is opened at a suitable position, and a suitable small flow rate is adjusted as a permanent decoking gas 23 to offset part of the coke produced by the secondary reaction in the cracking reaction, which can slow down the formation of coke, thereby extending the normal operation time of the equipment, reducing the product operation cost, and improving the equipment operation efficiency.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A hot carrier gas direct cracking system, characterized in that: include: The combustion reaction section, the cracking pipe section, the rapid cooling section and the gas-liquid and coke separation section are sequentially connected along the traveling direction of the hot carrier gas. The cracking pipe section is also provided with a resistance monitoring unit and a temperature detection unit along the pipeline direction. The resistance monitoring unit and the temperature detection unit cooperate to find the position of the furnace tube of the coking section; The combustion reaction section includes a burner, the burner is provided with a plurality of combustion gas inlets and at least one ignition device, the burner has a combustion chamber, and the plurality of combustion gas inlets and the ignition device extend to the combustion chamber; the outer side of the burner is provided with a cracking furnace raw material waste heat device and a cracking furnace raw material conveying pipeline arranged in a spiral manner, and the cracking furnace raw material conveying pipeline extends to the inner cavity of the cracking pipe section through the cracking furnace raw material inlet pipe; a rectifier is also provided at the gas inlet of the burner, and the plurality of combustion gas inlets include a first combustion gas inlet, a second combustion gas inlet and a third combustion gas inlet, the first combustion gas inlet is arranged at the axis of the rectifier and extends to the combustion chamber through the rectifier, the second combustion gas inlet is arranged obliquely to the first combustion gas inlet, and the third combustion gas inlet is arranged perpendicular to the first combustion gas inlet and extends to the inner cavity of the rectifier; wherein the gas fuel and the combustion-supporting oxygen enter the burner from the plurality of combustion gas inlets respectively, are ignited by the ignition device and burn in the combustion chamber, and the high-temperature flue gas generated after combustion enters the cracking pipe section; The cracking pipe section is provided with a plurality of decoking gas pipes and decoking gas outlet nozzles along the pipeline direction, and decoking is performed by introducing decoking gas into the decoking gas pipes of the corresponding furnace pipes.

2. The hot carrier gas direct cracking system according to claim 1, characterized in that: The burner is also provided with a cracking furnace raw material inlet, the end of the cracking furnace raw material inlet pipe of the cracking pipe section is provided with a cracking furnace raw material atomizing head, and the cracking furnace raw material waste heat device is used to preheat the cracking furnace raw material conveying pipeline; At the same time, after the cracking furnace raw material is preheated and heated through the cracking furnace raw material conveying pipeline, it is atomized by the cracking furnace raw material atomizing head and then directly cracked in the cracking pipe section. During this period, the resistance monitoring unit obtains real-time relevant data on the amount of coking in the tube by monitoring the change of resistance value between each section. The temperature detection unit detects the coking thickness during normal operation and the tube wall temperature during decoking through the temperature change on the furnace tube surface. According to the data fed back by the resistance monitoring unit and the temperature detection unit, the decoking gas pipe introduces decoking gas to remove the coking in the cracking pipe section. The cracked gas enters the rapid cooling section for rapid cooling, and then enters the gas-liquid and coke separation section for separation.

3. The hot carrier gas direct cracking system according to claim 1, characterized in that: The decoking gas includes a mixed gas of oxygen and / or water vapor and / or carbon dioxide and / or an inorganic salt inhibitor.

4. The hot carrier gas direct cracking system according to claim 1, characterized in that: The outlet of the gas-liquid and coke separation section is provided with a plurality of gas sensors, and the plurality of gas sensors are used to detect the content of a specific gas to obtain the final decoking effect.

5. The hot carrier gas direct cracking system according to claim 1, characterized in that: The burner has a burner inner wall, the closed space surrounded by the burner inner wall is the combustion chamber, the outer layer of the burner inner wall is provided with burner inner insulation, the outer layer of the burner inner insulation is provided with a burner outer surface, and the outer layer of the burner outer surface is provided with the cracking furnace raw material waste heat device.

6. The hot carrier gas direct cracking system according to claim 1, characterized in that: The decoking gas pipe is provided with a decoking gas valve at a portion outside the cracking pipe section, and the decoking gas pipe is provided with a decoking gas outlet nozzle at a portion inside the cracking pipe section.

7. The hot carrier gas direct cracking system according to claim 1, characterized in that: The upper part of the gas-liquid and coke separation section is also provided with a light hydrocarbon separation system connected to the gas phase, and the lower part of the gas-liquid and coke separation section is also provided with a liquid phase multilayer distillation system and / or a liquid phase oil decoking system.

8. The hot carrier gas direct cracking system according to claim 1, characterized in that: The cracking pipe section is arranged horizontally, inclined, or in one or more layers of spiral bending, and the outer layer of the cracking pipe section is provided with furnace tube outer insulation.

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