CN116445181A - A heat-carrying gas direct pyrolysis system with coke cleaning and coke monitoring - Google Patents

Abstract

The invention discloses a thermal carrier gas direct cracking system with decoking and coking monitoring, which comprises: the device comprises a combustion reaction section, a cracking section, a quenching section and a gas-liquid and coke separation section which are sequentially connected along the travelling direction of a carrier gas with heat, wherein the combustion reaction section comprises a combustor, the combustor is provided with a plurality of combustion gas inlets and at least one ignition device, the combustor is provided with a combustion cavity, and a plurality of combustion gas inlets and the ignition device extend to the combustion cavity; the cracking pipe section is provided with a plurality of decoking gas pipes, decoking gas outlet nozzles, a resistance monitoring unit and a temperature detecting unit along the pipeline direction; the outside of the burner is provided with a pyrolysis furnace raw material waste heat device and a pyrolysis furnace raw material conveying pipeline which is spirally arranged, and the pyrolysis furnace raw material conveying pipeline extends to the inner cavity of the pyrolysis pipe section through a pyrolysis furnace raw material inlet pipe. The invention solves the problems of real-time monitoring of coking, real-time decoking, fixed-point decoking and the like.

Description

A heat-carrying gas direct pyrolysis system with coke cleaning and coke monitoring

technical field

The invention relates to the field of olefin production, in particular to a heat-carrying gas direct cracking system with coke cleaning and coking monitoring.

Background technique

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 to measure the development level of a country's petrochemical industry. Although steam cracking is the most widely used method for the production of light olefins and the olefin yield has been optimized to the greatest extent, the current steam cracking process has high comprehensive energy consumption, large steam consumption, and long residence time. In addition, since the cracking furnace tube adopts boiler Indirect heating, resulting in high fuel consumption and carbon emissions. Therefore, it is feasible and practical to study the new process of naphtha cracking on the basis of the current production process. The cracking furnace is a high energy-consuming equipment in the ethylene plant, the research shows that the total steam cracking furnace The efficiency is about 43.4%, the combustion process of the radiant section /> The biggest loss. Therefore, the rational implementation of thermal management of energy-consuming devices such as ethylene will be a focal issue. Although steam cracking has been put into operation in industry for many years, the heating method of indirect heating of the cracking furnace tube through the boiler has not changed, and the phenomenon of tube blockage during operation has not been substantially improved, and the replacement of the furnace tube will cause huge economic losses. Therefore, the development has a high /> Olefin cracking technology with high efficiency, low carbon emission and long operation period has great industrial application prospects.

Steam cracking is the most commonly used method for industrial ethylene production. After the cracking furnace raw material is mixed with steam, it is passed into the high-temperature cracking furnace radiation furnace tube, and a cracking reaction occurs inside the furnace tube to produce hydrocarbon products such as ethylene and propylene. The steam cracking reaction of hydrocarbons in the radiant section of the cracking furnace will be accompanied by secondary reactions. Coke will be deposited on the inner wall of the furnace tube in the radiant section, and the continuous deposition of coke powder in the furnace tube will eventually lead 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, it is necessary to increase the temperature of the furnace tube wall, which will cause the local temperature of the furnace tube wall to be too high, which will reduce the service life of the furnace tube and increase Energy consumption during the reaction. The continuous deposition of the coke layer will lead to the continuous shrinking of the inner diameter of the furnace tube, which will increase the pressure drop of the raw material fluid in the furnace tube, reduce the amount of cracked raw materials participating in the reaction, and reduce the yield of alkenes. tools, and eventually even block the furnace tube, resulting in safety problems. Therefore, when the coking limit of a certain process requirement is reached, the radiant furnace tube 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, which will cause damage to the superalloy and reduce the temperature of the furnace tube. service life.

The coke cleaning process requires regular shutdown of the furnace for coking. The decoking gas generally enters from the pyrolysis inlet, and cannot directly affect the coking part, and cannot be cleaned under the condition of partial coking during operation. A series of problems such as the coking position cannot be monitored in real time.

Therefore prior art urgently needs to improve and develop.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a heat-carrying gas direct cracking system with decoking and coking monitoring, which can perform decoking operation by passing decoking gas into the decoking gas pipe corresponding to the furnace tube .

To achieve the above object, the present invention can adopt the following technical solutions to carry out:

A heat-carrying gas direct cracking system includes: a combustion reaction section, a cracking pipe section, a rapid cooling section, and a gas-liquid and coke separation section sequentially connected along the traveling direction of the heat-carrying gas.

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 cracking pipe section is provided with several decoking gas pipes, decoking gas outlet nozzles, resistance monitoring units and temperature detection units along the direction of the pipeline;

The outer side of the burner is provided with a cracking furnace raw material waste heat device and a spirally arranged cracking furnace raw material delivery pipeline, 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, and the cracking furnace The end of the 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 for preheating the cracking furnace raw material delivery pipeline;

Wherein, 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 pipe section, and at the same time After the cracking furnace raw material is preheated and heated through the cracking furnace raw material delivery 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 monitors the resistance between each section Value changes to obtain real-time relevant data on the coking amount in the tube. 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 feedback from the resistance monitoring unit and the temperature detection unit According to the data, the decoking gas pipe is passed into the decoking gas to remove the coking in the cracking pipe section, and the gas after cracking enters the rapid cooling and cooling section for rapid cooling and cooling, and then goes to the gas-liquid and coke separation section for separation.

In the heat carrier gas direct cracking system described above, further, the outlet of the gas-liquid and coke separation section is provided with various gas sensors, and various gas sensors are used to detect specific gas content to obtain the final decoking Effect.

In the heat-carrying gas direct cracking system described above, further, the upper part of the gas-liquid and coke separation section is provided with a power section, and the outlet of the power section is provided with various gas sensors, and various gas sensors are used for Specific gas content is detected to obtain the final decoking effect.

In the direct cracking system for heat carrier gas 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 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, the The third combustion gas inlet is arranged perpendicular to the first combustion gas inlet and extends to the inner chamber of the rectifier.

In the heat-carrying gas direct cracking system described above, further, the burner has an inner wall of the burner, and the closed space surrounded by the inner wall of the burner is the combustion chamber, and the outer layer of the inner wall of the burner is provided with a combustion chamber. The outer layer of the inner heat preservation of the burner is provided with the outer surface of the burner, and the outer layer of the outer surface of the burner is provided with the waste heat device for the raw material of the cracking furnace.

In the direct pyrolysis system of heat carrier gas as described above, further, the part of the decoking gas pipe outside the cracking pipe section is provided with a decoking gas valve, and the part of the decoking gas pipe inside the cracking pipe section A decoking gas outlet nozzle is provided.

As for the heat carrier gas direct cracking system described above, further, the outer layer of the cracking pipe section is provided with an outer insulation of the furnace tube.

As for the heat carrier gas direct cracking system described above, further, the upper part of the gas-liquid and coke separation section is also equipped 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 equipped with a liquid phase multilayer rectification system and/or liquid phase oil decoking system.

As for the heat carrier gas direct cracking system described above, further, the burner is also provided with a cracking furnace raw material inlet.

In the direct pyrolysis system of heat-carrying gas as described above, further, the pyrolysis pipe section is arranged horizontally, obliquely or in one or more layers of spiral bends.

As for the heat carrier gas direct cracking system described above, further, the decoking gas may be a mixed gas of oxygen and/or water vapor and/or carbon dioxide and/or inorganic salt inhibitors.

As for the heat carrier gas direct cracking system described above, further, the raw material inlet of the cracking furnace is equipped with an atomizing device.

As for the heat carrier gas direct cracking system mentioned above, further, the cracking system can be under high pressure or under normal pressure.

Compared with the prior art, the present invention has the beneficial effects of:

1. Several resistance monitoring units and temperature detection units are arranged on the outer pipe wall of the pyrolysis pipe section of the heat carrier gas direct pyrolysis system in the embodiment of the present invention. After the system is newly built or the furnace is shut down for overhaul and the furnace pipe is cleaned of coke, the initial operation measures each The benchmark data of the real-time monitoring of the coking section of the furnace tube can be compared with the real-time coking data of each section of the furnace tube when the system is running to find the position of the coking section of the furnace tube.

2. The heat-carrying gas direct cracking system in the embodiment of the present invention is provided with a decoking gas valve, which does not need to stop the furnace for decoking. By opening the corresponding decoking gas valve, the decoking gas is directly introduced into the corresponding furnace tube for decoking focus 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 brought in during the decoking process have a certain effect on cracking. At the same time, it can reduce the amount of carbon dioxide and water vapor at the raw material inlet of the corresponding cracking furnace, improve the continuous operation time of the equipment, greatly reduce the product cost, and improve equipment operation. Efficiency, and also reduce the energy consumption during shutdown and restart process.

3. The heat-carrying gas direct cracking system in the embodiment of the present invention is provided with a decoking gas valve. When the furnace is stopped for decoking, the decoking gas can be directly passed into the corresponding furnace tube by opening the corresponding decoking gas valve. Allowing the decoking gas to directly act on the coke can reduce the oxidation of the furnace tube, and at the same time reduce the time required for the decoking process of the furnace shutdown. At the same time, by comparing the real-time coking data of each section of the furnace tube during operation, the position of the decoking gas can be adjusted in time to effectively clean the coke.

4. The heat-carrying gas direct cracking system in 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, it is possible to offset part of the pyrolysis reaction. The coke produced by the secondary reaction can slow down the formation of coke, prolong the normal operation time of equipment, reduce the operating cost of products, and improve the operation efficiency of equipment.

5. In the heat-carrying gas direct cracking system of the embodiment of the present invention, the direct cracking of the heat-carrying gas generated by combustion can reduce the energy consumption and emission of the device, and the direct heat exchange has no heat transfer resistance, and the heat exchange efficiency is much higher than the indirect heat exchange , can greatly reduce device energy consumption and emissions, and improve Efficiency, increasing the cracking temperature and reducing the reaction residence time to achieve the purpose of increasing olefin production and efficiency, and has the advantages of convenient operation and low cost.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is a schematic structural diagram of a heat carrier gas direct cracking system according to an embodiment of the present invention.

Among them: 1. Combustion reaction section; 2. Cracking pipe section; 3. Quenching cooling section; 4. Gas-liquid and coke separation section; 5. Power section; 10. First combustion gas inlet; 11. Second combustion gas inlet; 12 1. Ignition device; 13. The third combustion gas inlet; 14. Rectifier; 15. Inner wall of the burner; 16. Inner insulation of the burner; 17. Outer surface of the burner; 18. Combustion cavity; Cracking furnace raw material waste heat device; 21. Cracking furnace raw material inlet pipe; 22. Cracking furnace raw material atomization 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. Heat preservation outside the furnace tube; 30. Cracking furnace raw material inlet; 40 Gas product outlet, 50. Non-gas product outlet.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Example:

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to Those steps or elements are not explicitly listed, but may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

It is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", "Radial", " The orientation or positional relationship indicated by "circumferential direction" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, Constructed and operative in a particular orientation and therefore are not to be construed as limitations of the invention.

In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined. In addition, unless otherwise clearly stipulated and limited, the terms "mounted", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical A connection can also be an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

In the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first and second feature may be in direct contact with the second feature through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the 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. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

Referring to Fig. 1, Fig. 1 is a structural schematic diagram of an embodiment of the heat carrier gas direct cracking system with coke cleaning and coking monitoring of the present invention. As shown in Figure 1, the heat carrier gas direct pyrolysis system with coke cleaning and coke monitoring includes: a combustion reaction section 1, a cracking pipe section 2, a quenching cooling section 3, and a gas-liquid and coke separation section connected in sequence along the direction of travel of the heat-carrying gas 4. The combustion reaction section 1 includes 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, a plurality of the combustion gas inlets and the ignition device The device 12 extends to the combustion chamber 18; the cracking pipe section 2 is provided with a number of decoking gas pipes 25, a resistance monitoring unit 27 and a temperature detection unit 28 along the pipeline direction; the outside of the burner is provided with a cracking furnace raw material waste heat device 20 and spirally arranged with a cracking furnace raw material delivery pipeline, the cracking furnace raw material delivery pipeline extends to the inner chamber of the cracking pipe section 2 through the cracking furnace raw material inlet pipe 21, and the end of the cracking furnace raw material inlet pipe 21 is provided with a cracking furnace The raw material atomizing head 22, the cracking furnace raw material waste heat device 20 is used for preheating the cracking furnace raw material delivery pipeline.

Specifically, gaseous fuel and combustion-supporting oxygen enter the burner from multiple combustion gas inlets, 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 chamber. Pipe section 2. At the same time, after the cracking furnace raw material is preheated and heated through the cracking furnace raw material delivery pipeline, it is atomized by the cracking furnace raw material atomizing head 22 and then directly cracked in the cracking pipe section 2. During this period, the resistance monitoring unit 27 Obtain real-time relevant data on the amount of coking in the tube by monitoring the subtle changes in the resistance values between the sections. The temperature detection unit 28 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 monitoring unit 27 and the temperature detection unit 28, the decoking gas pipe 25 is passed into the decoking gas 23 to remove the coking in the cracking pipe section 2, and the cracked gas enters the rapid cooling and cooling section 3 for rapid cooling and cooling , and then to the gas-liquid and coke separation section 4 for separation.

The heat-carrying gas direct cracking system with coke cleaning and coking monitoring in the embodiment of the present invention provides a technical solution to solve the problem of coking cleaning and coking monitoring in the cracking system. By setting the waste heat device 20 for the raw material of the cracking furnace, the cracking furnace is preheated The raw material delivery pipeline makes the cracking tube section 2 not need to be heated or directly contacted with the flame, so that some decoking gas pipes 25, resistance monitoring unit 27 and temperature detection unit 28 can be set on the outer tube wall of the cracking tube section 2 to monitor the cracking The coking real-time data of each furnace tube in pipe section 2, and then compare the monitored real-time coking data with the benchmark data of the real-time coking monitoring 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 for the first time. , the position of the furnace tube in the coking section can be found in time, and then the decoking operation is performed by passing the decoking gas 23 into the decoking gas pipe 25 corresponding to the 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 brought in 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 raw material inlet of the cracking furnace can increase the continuous operation time of the equipment and greatly reduce the product cost. , improve equipment operating efficiency, and also reduce energy consumption during shutdown and restart. In addition, the direct cracking of the heat carrier gas generated by combustion can reduce the energy consumption and emissions of the device, and the direct heat exchange has no heat transfer resistance, and the heat exchange efficiency is much higher than that of the indirect heat exchange, which can greatly reduce the energy consumption and emissions of the device, and improve Efficiency, increasing the cracking temperature and reducing the reaction residence time to achieve the purpose of increasing olefin production and efficiency, and has the advantages of convenient operation and low cost.

In the above technical solution, the burner may be a combustion system including pure oxygen or oxygen-enriched conditions, and it may be arranged horizontally or upward or downward or at any certain angle. Described burner has burner inner wall 15, and the closed space that described burner inner wall 15 surrounds is described combustion cavity 18, and the outer layer of described burner inner wall 15 is provided with burner inner insulation 16, and described burner inner The outer layer of the heat preservation 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.

The pyrolysis pipe section 2 is provided with several resistance monitoring units 27 and temperature detection units 28 along the pipeline direction, wherein the resistance monitoring unit 27 obtains real-time relevant data on the amount of coking in the pipe by monitoring the slight changes in the resistance values between the sections. The change of current value, or the tiny signal of voltage value change under constant current source, represents the change of coking amount in this interval by detecting the change of resistance in this interval. The temperature detection unit 28 is mainly based on thermocouples, and may include temperature sensors such as thermocouples, thermal resistors or thermal semiconductors. The temperature detection unit 28 can detect the approximate thickness of coke during normal operation and the temperature of the tube wall during decoking through the temperature change of the furnace tube surface, which can represent this point by detecting the temperature change during the smooth operation under the same inlet conditions Coke thickness. When in use, measure the real-time monitoring resistance and temperature benchmark data 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 for the first time, and the coking real-time resistance and temperature of each section of the furnace tube during operation Data comparison, so as to find the location of the furnace tube in the coking section. Among them, the resistance data needs to be coupled with the temperature to obtain the corresponding resistance value curves under various operating temperature conditions under the initial operation, and then compare the calculated reference resistance value corresponding to the temperature of each detection point under real-time operation with the actual resistance value detected in each section. Get the coke area. At the same time, the relative coking area can also be obtained through the temperature change of each detection point. When the heat-carrying gas direct cracking system in the embodiment of the present invention monitors the coking state, the resistance signal can be collected by the resistance monitoring unit 27 for monitoring, the temperature signal can also be collected by the temperature detection unit 28 for monitoring, or the resistance monitoring unit 27 and temperature can be used for monitoring. The detection unit 28 is used in combination for monitoring.

On the basis of the above embodiments, as an optional embodiment, a rectifier 14 is also provided at the gas inlet of the burner, and a plurality of the 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, and the second combustion gas inlet 11 is inclined to The first combustion gas inlet 10 is arranged, and 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 . Wherein, 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 for gas intake, and the remaining combustion gas inlets are used for combustion-supporting gas. The first combustion gas inlet 10 and the third combustion gas inlet 13 feed the same gas, or different gases.

In this embodiment, by setting the rectifier 14, the gas distribution in the combustion chamber 18 can be made more uniform, so that the combustion is more complete. During use, gas fuel and 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, while adjusting the gas The ratio of fuel and combustion-supporting oxygen makes the products after combustion have no oxygen or contain less oxygen. The high-temperature flue gas generated after combustion enters the inlet of the cracking pipe section 2 through the outlet 19 of the combustion reaction section. The raw material of the cracking furnace enters the pipeline from the raw material inlet 30 of the cracking furnace and is preheated by the waste heat device 20 of the raw material of the cracking furnace to raise the temperature. In another embodiment, the raw material of the cracking furnace can also be preheated by an external heat exchanger or jointly preheated by an external heat exchanger and the waste heat device 20 of the raw material of the cracking furnace, and then passed to the raw material inlet pipe 21 of the cracking furnace, and then passed through the cracking furnace After the raw material atomization head 22 is atomized, it is directly cracked in the cracking pipe section 2 . After cracking, the gas enters the rapid cooling and cooling section 3 for rapid cooling and cooling, and then goes to the gas-liquid and coke separation section 4 for separation. Further, the lower part of the gas-liquid and coke separation section 4 can also be connected to a liquid-phase multi-layer rectification system or a liquid-phase oil decoking system, and can also be connected to a liquid-phase oil decoking system before passing it into the cracking furnace raw material Inlet 30; the upper part of the gas-liquid and coke separation section 4 can also be connected to the light hydrocarbon separation system (cracked gas cryogenic separation system), and can also be connected to the power section 5. Further, 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 gas sensors are used to detect specific gas content, by detecting carbon dioxide, carbon dioxide, oxygen, etc. Oxygen content for ultimate decoking. In addition, the heat-carrying gas direct cracking system in this embodiment can also control the inlet pressures, including the inlet pressures of cracking furnace raw materials, gas fuel, combustion-supporting oxygen, and decoking gas 23, so that the system can maintain positive pressure operation.

In another embodiment, when in use, gas fuel and 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 in the combustion chamber by the ignition device 12. 18 internal combustion, while adjusting the ratio of gas fuel and combustion-supporting oxygen to make more oxygen in the combustion product. The high-temperature flue gas generated after combustion enters the inlet of the cracking pipe section 2 through the outlet 19 of the combustion reaction section. Simultaneously cracking furnace raw material stops feeding. After cracking, the gas enters the rapid cooling and cooling section 3 for rapid cooling and cooling, and then goes to the gas-liquid and coke separation section 4 for separation.

As an optional embodiment, in some embodiments, the part of the decoking gas pipe 25 outside the cracking pipe section 2 is provided with a decoking gas valve 24, and the decoking gas pipe 25 is in the The part inside the cracking pipe section 2 is provided with a decoking gas outlet nozzle 26 .

Specifically, in this embodiment, by setting the decoking gas valve 24, it is not necessary to stop the furnace for decoking. The specific operation is as follows: open the corresponding decoking gas valve 24 to adjust the appropriate flow rate at each point, pass into the decoking gas 23, and the decoking gas 23 enters the decoking gas pipe 25 and then enters the decoking gas outlet nozzle 26. Wherein, 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 of the inner surface of the furnace tube. Simultaneously, the high-pressure gas of the decoking gas outlet nozzle 26 can also effectively blow away the clogged coke. Preferably, before the decoking gas 23 enters the furnace tube, the temperature can be raised through an external heat exchanger, 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 may be a mixed gas of oxygen and/or water vapor and/or carbon dioxide and/or (inorganic salt) inhibitors. 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 brought in during the decoking process have a certain effect on cracking, and at the same time can reduce the amount of carbon dioxide and water vapor at the raw material inlet of the cracking furnace, improve the continuous operation time of the equipment, and greatly reduce the product cost. Reduce energy consumption during shutdown and restart. In addition, when the furnace is stopped for decoking, the corresponding decoking gas valve 24 can be opened to directly pass the decoking gas 23 into the corresponding furnace tube, so that the decoking gas 23 can directly act on the coke, which can reduce the oxidation of the furnace tube. At the same time, the time required for the furnace shutdown and decoking process is reduced. At the same time, by comparing the coking real-time data of each section of the furnace tube during operation, the entry position of the decoking gas 23 can be adjusted in time, so that coke can be effectively cleaned.

Further, the outer layer of the cracking pipe section 2 is provided with an insulating material furnace tube outer heat preservation 29, which can reduce the heat loss of heat exchange with the burner outer surface 17, and simultaneously increase the cracking gas inlet temperature. In addition, the furnace tubes of the cracking tube section 2 can spiral or spiral downwards, or can be arranged horizontally as shown in FIG. 1 , can also be arranged with the outlet downward, and can also be arranged obliquely downward. In addition, the heat-carrying gas direct cracking system in the embodiment of the present invention can be operated under high pressure conditions, or can be operated under normal pressure conditions.

On the basis of the above embodiments, as an optional embodiment, the decoking gas valve 24 can also be kept open during the stable operation of the heat carrier 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 the appropriate small flow rate as the regular decoking gas 23 to offset part of the pyrolysis reaction that will be accompanied by the coke produced by the secondary reaction, while also maintaining the decoking gas Outlet nozzle 26 unobstructed. The flow rate of each section as the retained gas can be different according to the coking situation. Generally, there are more middle parts and fewer beginning segments. At the same time, the data monitored by the resistance monitoring unit 27 and the temperature detection unit 28 can be used to adjust the flow rate of the decoking gas 23 in each section to keep the tube furnace unblocked for a long time. This operation can be maintained for a long period of time without stopping the furnace to clean the coke. In this embodiment, by opening the decoking gas valve 24 at a suitable position, and adjusting a suitable small flow rate as the permanent decoking gas 23 to offset part of the pyrolysis reaction that will be accompanied by the coke produced by the secondary reaction, the formation of coke can be slowed down. Thereby prolonging equipment uptime, reducing product operating costs, and improving equipment operating efficiency.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and its purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the essence of the content of the present invention shall fall within the protection scope of the present invention.

Claims (10)

1. A heat-carrying gas direct cracking system, is characterized in that, comprises: along the combustion reaction section that is connected successively along band heat-carrying gas advance direction, cracking pipe section, rapid cooling cooling section and gas-liquid and coke separation section, The cracking pipe section is provided with several decoking gas pipes and decoking gas outlet nozzles along the direction of the pipeline, and the decoking gas is passed into the decoking gas pipe corresponding to the furnace tube to decoke. 2. The heat-carrying gas direct cracking system according to claim 1, characterized in that the cracking pipe section is also provided with a resistance monitoring unit and a temperature detection unit along the pipeline direction, and the resistance monitoring unit and the temperature detection unit cooperate to find that the coking section furnace tube s position. 3. The heat carrier gas direct cracking system according to claim 2, wherein the combustion reaction section comprises a burner, and the burner is provided with a plurality of combustion gas inlets and at least one ignition device, and the burner having a combustion chamber into which a plurality of said combustion gas inlets and said ignition means extend; The outer side of the burner is provided with a cracking furnace raw material waste heat device and a spirally arranged cracking furnace raw material delivery pipeline, and the cracking furnace raw material delivery pipeline extends to the inner chamber 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 a plurality of the combustion gas inlets include a first combustion gas inlet, a second combustion gas inlet and a third combustion gas inlet, and the first combustion gas inlet is arranged on the At the axis of the rectifier and extending 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 perpendicular to the first combustion gas inlet disposed, and extending into the lumen of the rectifier; Wherein, gas fuel and combustion-supporting oxygen enter the burner from multiple combustion gas inlets, 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 pipe section. 4. heat carrier gas direct cracking system according to claim 3, is characterized in that, described burner is also provided with cracking furnace raw material inlet, and the end of the cracking furnace raw material inlet pipe of described cracking pipe section is provided with cracking furnace raw material mist A chemical head, the cracking furnace raw material waste heat device is used to preheat the cracking furnace raw material delivery pipeline; At the same time, after the cracking furnace raw material is preheated and heated through the cracking furnace raw material delivery 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 monitors the The change of the resistance value obtains real-time relevant data on the amount of coking in the tube. The temperature detection unit detects the coking thickness during normal operation and the temperature of the tube wall during decoking through the temperature change on the surface of the furnace tube. According to the resistance monitoring unit and the temperature detection unit According to the feedback data, the decoking gas pipe is passed into the decoking gas to remove the coking in the cracking pipe section, and the gas after cracking enters the rapid cooling and cooling section for rapid cooling and cooling, and then goes to the gas-liquid and coke separation section for separation. 5. The heat-carrying gas direct cracking system according to claim 1, characterized in that the decoking gas comprises a mixed gas of oxygen and/or water vapor and/or carbon dioxide and/or inorganic salt inhibitors. 6. The heat-carrying gas direct cracking system according to claim 1, characterized in that, the outlet of the gas-liquid and coke separation section is provided with multiple gas sensors, and multiple gas sensors are used to detect specific gas content, for the final defocused effect. 7. The heat-carrying gas direct cracking system according to claim 3, wherein the burner has a burner inner wall, and the enclosed space surrounded by the burner inner wall is the combustion chamber, and the burner inner wall The outer layer of the burner is provided with heat preservation inside the burner, the outer layer of the inner heat preservation of the burner is provided with the outer surface of the burner, and the outer layer of the outer surface of the burner is provided with the waste heat device for the raw material of the cracking furnace. 8. The heat carrier gas direct cracking system according to claim 1, characterized in that, the part of the decoking gas pipe is provided with a decoking gas valve outside the cracking pipe section, and the decoking gas pipe is in the The part inside the cracking pipe section is provided with a decoking gas outlet nozzle. 9. The heat-carrying 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 gas-liquid and coke separation section The lower part is also equipped with a liquid-phase multi-layer rectification system and/or a liquid-phase oil decoking system. 10. The direct cracking system of heat-carrying gas according to claim 1, characterized in that, the cracking pipe section is arranged horizontally, inclined or arranged in one or more layers of spiral bending, and the outer layer of the cracking pipe section is provided with a furnace Insulation outside the tube.