Ethylene butter reprocessing method and device

Abstract

The invention discloses an ethylene butter recycling method and device, and belongs to the technical field of delayed coking. The method comprises the steps that S1, ethylene butter and dirty diesel oil are mixed and stored in a storage tank in a tank area; s2, the mixed liquid in the storage tank in the tank field is conveyed to a special blind cover at the top of the coke tower through a pump, and the special blind cover stretches into the coke tower by 100-500 mm so as to inject the mixed liquid into a low-gas-velocity area in the coke tower; s3, in the coke tower, the mixed liquid and the high-temperature oil gas are subjected to contact cracking, a polymer and light cracking gas are generated, the polymer is settled to a coke layer of the coke tower, and the light cracking gas enters a fractionating tower along with the oil gas of the coke tower; and S4, fractionating the pyrolysis gas in a fractionating tower to obtain rich gas, naphtha, coker diesel oil and coker gas oil. By mixing the ethylene butter and the dirty diesel oil and then reprocessing, the traditional hazardous waste is successfully converted into a high-value chemical product, the environmental protection pressure of direct treatment of the hazardous waste is effectively avoided, the environmental protection management process of an enterprise is simplified, and the generation amount of the hazardous waste is reduced from the source.

Description

Technical Field

[0001] The invention belongs to the technical field of delayed coking, and in particular relates to an ethylene butter recycling method and an ethylene butter recycling device. Background Art

[0002] During the alkaline washing process, the heavy components of ethylene cracking gas and dienes polymerize to form yellow viscous polymers. In severe cases, it becomes yellow mud, which is usually called "butter".

[0003] The main components of butter are cross-linked polymers of dienes and unsaturated hydrocarbons or aldehyde-ketone condensates with benzene rings. Generally speaking, because butter is strongly alkaline and easily oxidized, it is usually treated as "hazardous waste". With increasingly stringent environmental protection requirements and hazardous waste management requirements, disposal costs have further increased, increasing the production costs of enterprises. Summary of the Invention

[0004] The present invention aims to solve the above problems in the prior art and proposes an ethylene butter recycling method and device.

[0005] The present invention can be achieved through the following technical solutions:

[0006] An ethylene butter recycling method comprising:

[0007] S1. Mixing ethylene grease and diesel waste oil and storing them in a tank in a tank farm;

[0008] S2. The mixed liquid in the tank in the tank area is pumped to the special blind cover on the top of the coke drum. The special blind cover extends 100-500mm into the coke drum to inject the mixed liquid into the low gas velocity area in the coke drum;

[0009] S3. In the coke drum, the mixed liquid contacts and the high-temperature oil and gas to generate polymer and light cracked gas. The polymer settles to the coke layer of the coke drum, and the light cracked gas enters the fractionation tower along with the oil and gas in the coke drum.

[0010] S4. The cracked gas is fractionated in a fractionating tower to obtain rich gas, naphtha, coking diesel and coking wax oil.

[0011] As a further improvement of the present invention, in step S1, the proportion of diesel oil in the mixed liquid is 20%-40%.

[0012] As a further improvement of the present invention, in step S3, the system pressure of the coke drum is set to 0.10Mpa-0.15Mpa, and the temperature inside the coke drum is 415-420°C, so that the mixed liquid contacts and cracks with the high-temperature oil and gas in the coke drum.

[0013] As a further improvement of the present invention, in step S3, a venting tower is also included, which receives hot heavy wax oil input from the outside, and the bottom of the venting tower outputs quenching oil to the outlet pipeline at the top of the coke tower, and the light cracked gas and oil gas to be output to the distillation tower are cooled by the quenching oil.

[0014] As a further improvement of the present invention, the gas phase output from the top of the vent tower is separated into waste oil, acidic water and gas by a three-phase separator and transported outwards respectively;

[0015] Part of the quenching oil output from the bottom of the vent tower passes through the filter, the vent bottom pump, and the cooling water tank in sequence and then flows back to the top of the vent tower to maintain the liquid phase temperature in the vent tower.

[0016] As a further improvement of the present invention, in step S4, a temperature gradient is established in the fractionation tower and the fractionation tower is divided from bottom to top into a heavy wax oil section, a light wax oil section, a diesel section, and a gas-rich section, wherein:

[0017] Rich gas section products: extract rich gas and naphtha, and control the tower top pressure at 0.06-0.18MPa;

[0018] Diesel section products: extract diesel fraction with a temperature of 170-220℃;

[0019] Light wax oil products: extraction temperature of light wax oil is 200-280℃;

[0020] Heavy wax oil section products: heavy wax oil with extraction temperature of 325-375℃.

[0021] As a further improvement of the present invention, in step S4, the following systems are configured from bottom to top in the fractionation tower and are used to control the temperature gradient:

[0022] Tower bottom circulating oil system: used to maintain the tower bottom temperature at 320-380℃ and adjust the thermal balance of the distillation tower through circulating oil;

[0023] Heavy wax oil system: control the heavy wax oil extraction temperature at 325-375℃;

[0024] Light wax oil stripper system: removes light components through stripping steam to ensure that the flash point of light wax oil is ≥65℃;

[0025] Mid-section reflux system: located between the diesel section and the light wax oil section, used to inject mid-section reflux liquid with a temperature of ≤190°C to adjust the fractionation efficiency of diesel and light wax oil;

[0026] Diesel system: control the extraction temperature of diesel fraction at 170-220℃;

[0027] Top circulation reflux system: inject top circulation reflux liquid with a temperature of ≤120℃ into the top section of the tower, and dynamically adjust the top temperature to maintain at 80-120℃;

[0028] Tower top gas phase extraction system: control the tower top pressure to 0.06-0.18MPa, extract rich gas and naphtha.

[0029] As a further improvement of the present invention, after step S4, the method further includes:

[0030] S5. Regularly switch the ethylene butter injection to the new coke tower according to the coking cycle of the coke tower. When switching, close the injection line quick-cut valve of the original coke tower to stop injecting the mixed liquid, and open the steam purge valve of the original coke tower to allow anti-coking steam to pass.

[0031] As a further improvement of the present invention, the specific switching operation in step S5 includes:

[0032] S51. Confirm that the four-way valve has been switched to the new coke drum, close the quick-cut valve of the original coke drum injection line, and start the new coke drum injection process;

[0033] S52. Close the steam purge valve behind the quick-cut valve of the new coke drum injection line, open the valve in front of the quick-cut valve of the new coke drum injection line, open the quick-cut valve of the new coke drum injection line, and monitor the temperature and pressure at the top of the new coke drum;

[0034] S53. Close the quick-cut valve and the front hand valve of the original coke drum injection line, open the steam purge valve of the original coke drum injection line, and pass anti-coking steam;

[0035] S54. According to the pressure and top temperature of the new coke tower, slowly fully open the front hand valve of the quick-cut valve of the injection line of the new coke tower.

[0036] As a further improvement of the present invention, in step S5, the amount of steam injected into the original coke drum is 200-500 kg / h, and the purge is continued for 8-12 minutes.

[0037] Also provided is an ethylene butter recycling device, comprising:

[0038] There are multiple coke towers, each with a special blind cover on top. The cover extends into a low-gas-velocity area of 100-500 mm inside the tower. Ethylene grease and diesel oil are mixed and stored in a tank in the tank farm. The mixture is pumped to the cover and injected into the low-gas-velocity area of the tower. The mixture comes into contact with the high-temperature oil and gas and is cracked to produce polymers and light cracked gas. The polymers settle into the coke layer of the tower, and the light cracked gas enters the fractionation tower along with the oil and gas in the tower.

[0039] The top of each coke tower is connected to the bottom of the fractionating tower. The cracking gas and high-temperature oil and gas at the top of the coke tower enter the bottom of the fractionating tower. The cracking gas is fractionated through the fractionating tower to obtain rich gas, naphtha, coking diesel and coking wax oil.

[0040] As a further improvement of the present invention, it also includes a venting tower, the bottom of which is connected to the outlet pipelines at the top of each coke tower and is used to output quenching oil to cool the cracked gas and high-temperature oil and gas.

[0041] As a further improvement of the present invention, the bottom of the vent tower has a cooling circulation system, including a filter, a vent tower bottom pump and a cooling water tank. The bottom of the vent tower is connected to its top through the filter, the vent tower bottom pump and the cooling water tank in sequence.

[0042] As a further improvement of the present invention, a three-phase separator is connected to the top of the vent tower, and the gas phase output from the top of the tower is separated into gas, acidic water and waste oil by the three-phase separator and discharged to designated areas respectively.

[0043] As a further improvement of the present invention, the top, middle and bottom of the distillation tower are respectively provided with a top circulation pump, a middle circulation pump and a bottom circulation pump, each circulation pump is used to inject circulating liquid into the distillation tower to adjust the temperature of the area.

[0044] As a further improvement of the present invention, the distillation tower is equipped with a bottom circulating oil system, a heavy wax oil system, a light wax oil stripping tower system, a middle reflux system, a diesel system, a top reflux system, and a top gas phase extraction system from bottom to top.

[0045] As a further improvement of the present invention, the bottom circulating oil system is provided with a bottom circulating pump and regulates the heat balance of the distillation tower through circulating oil;

[0046] The heavy wax oil system is equipped with a heavy wax oil pump, which transports part of the heavy wax oil outward and returns the other part of the heavy wax oil to the distillation tower;

[0047] The light wax stripping tower system is equipped with a light wax stripping tower and a light wax oil pump. The light wax stripping tower removes light components through stripping steam, and the light components flow back into the fractionation tower. The light wax oil is transported outwards through the light wax oil pump.

[0048] The mid-section reflux system is equipped with a mid-section pump, which is used to inject mid-section reflux liquid with a temperature of ≤190℃ to adjust the fractionation efficiency of diesel and light wax oil;

[0049] The diesel system is equipped with a diesel pump, which transports part of the diesel outwards and returns the other part to the distillation tower;

[0050] The top circulation reflux system is equipped with a top circulation pump, which is used to inject top circulation reflux liquid with a temperature of ≤120℃ into the top of the tower, and dynamically adjust the top temperature of the tower to maintain at 80-120℃;

[0051] The top gas extraction system transports the top oil and gas of the distillation tower to the outside through the transmission pipeline.

[0052] As a further improvement of the present invention, each coke tower is provided with an injection line quick-cut valve and a steam purge valve. The mixture of ethylene butter and diesel oil is injected into the coke tower through the injection line quick-cut valve, and steam is purged into the coke tower through the steam purge valve.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] 1. Significantly reduce the burden of hazardous waste treatment: By mixing ethylene butter with diesel oil and then recycling it, traditional hazardous waste is successfully converted into high-value chemical products, effectively avoiding the environmental pressure of direct hazardous waste treatment, simplifying the company's environmental management process, and reducing the amount of hazardous waste generated at the source.

[0055] 2. Improve resource recycling efficiency: Utilize the high-temperature cracking characteristics of the coke tower to convert the difficult-to-treat components in ethylene butter into light oil and gas and settleable polymers, realize the resource regeneration of waste, form a closed environmental protection tax chain, and maximize the utilization rate of raw materials.

[0056] 3. Efficient polymer sedimentation: Through the design of a special blind cover on the side of the top of the coke drum, the mixture of ethylene butter and diesel oil is injected into the low-gas velocity area of the coke drum, which is conducive to the sedimentation of polymer particles generated after the thermal reaction, avoiding the problem of being unable to settle smoothly due to strong airflow, and even being carried into the subsequent processing links to cause pollution or blockage. At the same time, the light components in the mixture are more easily mixed with oil and gas and rise to the fractionation tower together with the oil and gas, thereby improving the separation efficiency and quality of light cracked gas;

[0057] 4. Enhance product separation accuracy and quality: The multi-section temperature control system of the distillation tower (such as the high-temperature section at the bottom of the tower, gradient reflux in the middle section, and low-temperature control at the top of the tower) works synergistically to accurately separate components with different boiling points, significantly improving the purity and stability of products such as naphtha and diesel to meet high-end market needs.

[0058] 5. Achieve energy conservation and equipment protection throughout the entire process: The combination of the vent tower quenching oil circulation system and the fractionating tower heat balance design pre-cools high-temperature oil and gas while recovering waste heat, reducing overall system energy consumption; modular switching operations and anti-coking measures extend the service life of the coke tower and pipelines, reducing maintenance frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a process flow chart of the ethylene butter recycling of the present invention.

[0060] In the figure, 100, coke tower; 110, special blind cover;

[0061] 200, vent tower; 210, three-phase separator; 211, sewage pump; 212, waste oil pump; 220, filter; 230, vent tower bottom pump; 240, cooling water tank;

[0062] 300, distillation tower; 310, top circulation pump; 320, middle section pump; 330, bottom circulation pump; 340, diesel pump; 350, light wax stripping tower; 351, light wax oil pump; 360, heavy wax oil pump. DETAILED DESCRIPTION

[0063] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical method of the present invention, but the present invention is not limited to these embodiments.

[0064] like Figure 1 As shown, the present invention provides an ethylene butter recycling method, comprising:

[0065] S1. Mixing and storage: Ethylene butter is mixed with 20%-40% diesel oil and stored in tanks in the tank farm. This mixing not only helps improve the fluidity of ethylene butter, but also reduces its tendency to self-aggregate during storage and transportation, thereby reducing the risk of pipeline blockage;

[0066] S2. Delivery to the top of the coke drum 100: The mixed liquid in the tank in the tank area is pumped to the special blind cover 110 on the side of the top of the coke drum 100 at a flow rate of no more than 10 t / h and a pressure of 1.2 MPa-2.0 MPa. The special blind cover 110 is designed to extend 100-500 mm into the coke drum 100, ensuring that the mixed liquid can be accurately injected into the low-gas velocity area in the coke drum 100, avoiding turbulence and uneven distribution problems that may be caused by high-gas velocity areas;

[0067] S3. Cracking reaction: In the coke drum 100, the mixed liquid contacts the high-temperature oil and gas to generate a cracking reaction, producing polymers and light cracked gas. The polymers are deposited in the coke layer of the coke drum 100, while the light cracked gas enters the fractionation tower 300 along with the oil and gas in the coke drum 100. In this process, due to the use of specific design and operating conditions, the cracking reaction is more efficient and the product separation is more complete.

[0068] S4, fractionation treatment: The cracked gas is fractionated in the fractionation tower 300 according to different temperature gradients, and finally valuable products such as rich gas, naphtha, coker diesel and coker gas oil are obtained.

[0069] It should be noted that, due to the flow characteristics of oil and gas, different heights and positions will have different airflow velocities in the coke drum 100. Generally, the airflow velocity near the top of the drum is faster because this is the main channel for the oil and gas to rise. In contrast, low airflow velocity areas will form at certain specific locations (such as the side of the top of the drum).

[0070] These areas are characterized by slower gas flows.

[0071] The specially designed blind cover 110 on the top side of the coke drum 100 injects the mixture of ethylene butter and diesel oil into the low-gas velocity area of the coke drum 100, which facilitates the sedimentation of polymer particles generated after the thermal reaction and prevents them from being blocked by strong airflow and even being carried into subsequent processing steps, causing pollution or blockage. At the same time, the light components in the mixture are more easily mixed with the oil and gas and rise to the distillation tower 300 along with the oil and gas, improving the separation efficiency and quality of the light cracked gas. Through the above steps, the recycling of ethylene butter is achieved, which brings at least the following advantages:

[0072] 1. Reduce the cost of hazardous waste treatment: In traditional methods, ethylene butter is usually treated as hazardous waste, which is very costly. This invention significantly reduces the environmental protection costs of enterprises by converting it into useful products;

[0073] 2. Optimize resource utilization: By converting ethylene butter into valuable chemicals, effective resource recycling is achieved, improving overall economic benefits;

[0074] 3. Improve production safety: By reducing the need for hazardous waste treatment, the environmental risks and safety hazards faced by enterprises are reduced, and the safety and stability of production are improved.

[0075] Preferably, in step S3, the system pressure of the coke drum 100 is set to 0.10Mpa-0.15Mpa, and the temperature inside the coke drum 100 is 415-420°C, wherein,

[0076] Controlling the temperature in the coke drum 100 within the range of 415°C to 420°C ensures that the components in the mixed liquid are fully cracked to produce the desired light cracked gas and polymer. This temperature range is the optimal reaction temperature verified by experiments. Too high or too low a temperature will affect the cracking efficiency and product quality.

[0077] The system pressure of the coke drum 100 is set at 0.10MPa to 0.15MPa, which helps to maintain appropriate gas fluidity and reaction rate. Lower pressure is conducive to gas diffusion, making the contact between the mixed liquid and high-temperature oil and gas more uniform and sufficient, thereby improving the overall efficiency of the cracking reaction.

[0078] Under the above conditions, the generated light cracked gas can more easily rise to the distillation tower 300 along with the high-temperature oil and gas in the coke tower 100 for further separation. The precise control of temperature and pressure helps to form a stable airflow and reduce the residence time of the light components in the coke tower 100, thereby improving the separation efficiency of the light cracked gas.

[0079] Preferably, in step S3, a vent tower 200 system is also introduced to improve the efficiency and safety of the entire process. The following is a detailed description of the vent tower 200 system:

[0080] 1. Receiving hot heavy wax oil input from the outside: The venting tower 200 receives hot heavy wax oil from the outside. After entering the venting tower 200, these heavy wax oils are converted into quench oil through a series of processing steps.

[0081] 2. Cooling light cracked gas and oil gas with quenching oil: The quenching oil output from the bottom of the venting tower 200 is transported to the outlet pipeline at the top of the coke tower 100, and is used to cool the light cracked gas and oil gas to be output from the coke tower 100 to the distillation tower 300. This step can effectively prevent high-temperature gas from directly entering the distillation tower 300 and causing overheating or damage to the equipment, and also reduces energy consumption in the subsequent separation process.

[0082] The gas phase at the top of the vent tower 200 is separated by a three-phase separator 210:

[0083] 1. Gas phase separation: The gas phase output from the top of the vent tower 200 is processed by a three-phase separator and separated into dirty oil, acidic water and gas. This separation method not only helps to purify the gas, but also recovers valuable by-products such as dirty oil and gas, while disposing of harmful acidic water and reducing environmental pollution.

[0084] Utilization of Separated Products: The separated waste oil is pumped out via waste oil pump 212 and can be recycled or used as a raw material for other processes. The gas can be burned to generate energy to support the energy needs within the factory. The acidic water is pumped out via sewage pump 211 and properly handled in accordance with environmental protection requirements to avoid environmental pollution.

[0085] Quick cooling oil circulation system at the bottom of vent tower 200:

[0086] Part of the quenching oil output from the bottom of the venting tower 200 will pass through the filter 220, the venting tower bottom pump 230, and the cooling water tank 240 in sequence and then flow back to the top of the venting tower 200. This process helps maintain the temperature stability of the liquid phase in the venting tower 200. The filter 220 ensures the cleanliness of the quenching oil and prevents impurities from clogging the pipeline or other equipment; the cooling water tank 240 adjusts the temperature of the quenching oil to keep it within an appropriate range, which not only ensures the cooling effect but also avoids equipment damage caused by excessive temperature.

[0087] By setting up the vent tower 200, the quench oil is continuously output to pre-cool the light cracked gas and oil gas, thereby reducing their temperature when entering the distillation tower 300, improving the cooling efficiency, reducing the load of the distillation tower 300, and extending the service life of the equipment.

[0088] Preferably, in step S4, the fractionation tower 300 has a total of 43 trays, and a temperature gradient is established in the fractionation tower 300 and is divided from bottom to top into a heavy wax oil section (6-10 layers), a light wax oil section (11-18 layers), a diesel section (26-34 layers), and a gas-rich section (43 layers), wherein:

[0089] Rich gas section products: The extraction temperature is rich gas and naphtha, and the pressure at the top of the tower is controlled at 0.06-0.18MPa. Controlling the pressure at the top of the tower helps to adjust the ratio of gas components, ensuring efficient separation and obtaining high-quality products;

[0090] Diesel section products: Extraction temperature 170-220 ℃ diesel fraction, this section is mainly responsible for extracting diesel fraction, controlling the appropriate extraction temperature is crucial to ensure the quality of diesel;

[0091] Light wax oil products: Extract light wax oil at a temperature of 200-280°C. This section is mainly responsible for extracting light wax oil. This type of product has a high energy density and is suitable for a variety of applications, such as fuel oil or chemical raw materials.

[0092] Heavy wax oil products: Heavy wax oil with a temperature of 325-375℃ is extracted. Within this temperature range, heavier hydrocarbon components are extracted as heavy wax oil products. These heavy wax oils can be further processed or directly used for specific industrial purposes.

[0093] By precisely setting the temperature range of each section, products within different boiling point ranges can be effectively separated, thereby improving the purity and quality of each product. This method can not only recover valuable chemicals from ethylene butter, but also maximize the conversion of all available resources into useful products, reduce waste emissions, and embody the concept of green chemistry.

[0094] Furthermore, in step S4, the following systems are configured from bottom to top in the fractionation tower 300 and are used to control the temperature gradient:

[0095] Tower bottom circulating oil system (layers 1-5): used to maintain the tower bottom temperature at 320-380°C and adjust the thermal balance of the fractionating tower 300 through circulating oil, ensuring the optimal operating temperature of the heavy wax oil section and facilitating the effective separation of heavy components;

[0096] Heavy wax oil system (6-10 layers): Controlling the extraction temperature of heavy wax oil at 325-375°C ensures the quality and yield of heavy wax oil while avoiding energy waste or product degradation caused by overheating;

[0097] Light wax oil stripping tower system (11-18 floors): removes light components through stripping steam to ensure the flash point of light wax oil is ≥65°C, improving the safety and storage stability of light wax oil and reducing risks during transportation and use;

[0098] Mid-section reflux system (19-25 floors): Located between the diesel section and the light wax oil section, it is used to inject mid-section reflux liquid with a temperature of ≤190°C. By precisely controlling the temperature difference between the two sections, the separation accuracy and quality of these two important products are improved;

[0099] Diesel system (26-34 floors): Controls the extraction temperature of the diesel fraction at 170-220°C, ensuring the quality of the diesel product and meeting strict fuel specifications;

[0100] Top reflux system (35-42 floors): injects top reflux liquid with a temperature of ≤120°C into the top section of the tower, dynamically adjusting the top temperature to maintain at 80-120°C, effectively controlling the pressure and temperature at the top of the tower, and creating ideal conditions for efficient separation of rich gas and naphtha;

[0101] Top gas extraction system (43rd floor): controls the top pressure at 0.06-0.18 MPa, extracts rich gas and naphtha, ensures efficient separation and collection of gas components, and maintains the pressure balance of the entire distillation tower 300.

[0102] The key design logic is described as follows:

[0103] 1. Matching of tray distribution and temperature gradient:

[0104] The temperature decreases from bottom to top: the high temperature (320-380℃) at the bottom of the tower (1-5 layers) separates the heavy components, and the low temperature (80-120℃) at the top layer (43 layers) separates the light gas products, which complies with the thermodynamic laws of the distillation tower.

[0105] Distribution of tray numbers: Among the 43 trays, every 5-8 trays correspond to a separation section, ensuring a stable temperature gradient between adjacent systems (e.g., the reflux temperature difference between the diesel section and the middle section is ≥50°C).

[0106] 2. System location and functional coordination:

[0107] Light wax oil stripping tower system (11-18 floors): Located below the middle reflux system, it uses the upward flow of stripping steam to contact the liquid light wax oil in countercurrent to enhance the removal of light components (flash point ≥ 65°C).

[0108] Top reflux system (35-42 floors): Through heat exchange between low-temperature reflux liquid and rising gas phase, the temperature fluctuation of the tower top is suppressed (controlled at 80-120℃), creating stable conditions for the gas phase extraction system (43 floors).

[0109] 3. Pressure balance control:

[0110] Tower top gas phase extraction system (43rd floor): By adjusting the extraction pressure (0.06-0.18MPa), the pressure drop gradient of the entire tower is controlled to ensure the distillation efficiency of each section.

[0111] By precisely controlling the operating parameters of each section, the quality of various products (such as rich gas, naphtha, diesel, light wax oil and heavy wax oil) can be significantly improved to meet the market demand for high-quality chemical products. In addition, the reasonable configuration of the temperature gradient and reflux system in the distillation tower 300 helps to fully utilize thermal energy, reduce unnecessary energy consumption, and lower production costs.

[0112] Preferably, after step S4, the method further includes:

[0113] S5. Regularly switch the ethylene butter injection to the new coke drum 100 according to the coking cycle of the coke drum 100. When switching, close the injection line quick-cut valve of the original coke drum 100 to stop injecting the mixed liquid, and open the steam purge valve of the original coke drum 100 to allow anti-coking steam to pass.

[0114] Specifically, the specific switching operation in step S5 includes:

[0115] S51: Confirm that the four-way valve has been switched to the new coke drum 100, close the quick-cut valve of the injection line of the original coke drum 100, and start the injection process of the new coke drum 100;

[0116] S52. Close the steam purge valve behind the quick-cut valve of the injection line of the new coke drum 100, open the valve in front of the quick-cut valve of the injection line of the new coke drum 100, open the quick-cut valve of the injection line of the new coke drum 100, and monitor the temperature and pressure at the top of the new coke drum 100;

[0117] S53. Close the quick-cut valve and the front hand valve of the injection line of the original coke drum 100, open the steam purge valve of the injection line of the original coke drum 100, and start to introduce anti-coking steam (usually 1.3 MPa steam) for 8-12 minutes. The steam volume is controlled between 200-500 kg / h to effectively prevent coke formation, reduce equipment wear, and extend its service life.

[0118] S54. According to the pressure and top temperature of the new coke drum 100, slowly fully open the front hand valve of the quick-cut valve of the injection line of the new coke drum 100 to ensure that the mixed liquid enters the new coke drum 100 smoothly and avoid pressure fluctuations or other unstable factors caused by excessive flow.

[0119] By precisely controlling the operating conditions at each stage, a smooth transition between different coke drums 100 is ensured, thereby maintaining product quality consistency. Standardized operating procedures improve work efficiency, make the switching process smoother, and reduce downtime.

[0120] In addition, if the unit stops refining ethylene butter, the pipeline needs to be replaced with diesel or purged with steam to prevent the ethylene butter from self-aggregating due to long-term static conditions and causing pipeline blockage. It is also necessary to set up hot water heating (60℃~70℃) for the ethylene butter refining pipeline to prevent the pipeline from condensing. However, medium-pressure steam heating shall not be set up to prevent the temperature from being too high and causing the ethylene butter to vaporize or react in the pipeline.

[0121] For better explanation, attached are the operating parameter tables of the coke drum 100 and the fractionation tower 300 (see Table 1), as well as the comparison of the fractionation side products before and after ethylene butter recycling (see Tables 2-5):

[0122]

[0123]

[0124] Table 1 List of operating parameters

[0125]

[0126] Table 2 Coking stabilized gasoline

[0127]

[0128]

[0129] Table 3 Coking diesel

[0130]

[0131] Table 4 Coking gas oil

[0132]

[0133]

[0134] Table 5 Petroleum coke

[0135] In addition, the present invention also provides an ethylene butter recycling device, comprising:

[0136] Coke drums 100 can be installed in multiple locations depending on production scale. Each drum is topped with a custom blind cover 110 designed to extend 100-500 mm into the low-velocity zone within the drum. The mixed liquid is pumped through the blind cover 110 and injected into the low-velocity zone within the drum, where it comes into contact with the high-temperature oil and gas, causing a cracking reaction. The resulting polymer settles into the coke layer, while the light cracked gas rises with the oil and gas into the fractionation tower 300.

[0137] The top of each coke tower 100 is connected to the bottom of the distillation tower 300. In the distillation tower 300, the cracked gas and high-temperature oil and gas are separated into different products such as rich gas, naphtha, coking diesel and coking wax oil according to different boiling points. This graded separation not only improves resource utilization, but also ensures the purity and quality of the products.

[0138] Preferably, a vent tower 200 is further included, the bottom of which is connected to the outlet pipelines at the top of each coke tower 100 and is used to output quench oil to cool the cracked gas and high-temperature oil and gas.

[0139] Preferably, the bottom of the vent tower 200 has a cooling circulation system, including a filter 220, a vent tower bottom pump 230 and a cooling water tank 240. The bottom of the vent tower 200 is connected to the top of the tower through the filter 220, the vent tower bottom pump 230 and the cooling water tank 240 in sequence.

[0140] Preferably, the top of the vent tower 200 is connected to a three-phase separator 210, and the gas phase output from the top of the tower is separated into gas, acidic water, and waste oil by the three-phase separator 210 and discharged to designated areas respectively.

[0141] Preferably, the top, middle and bottom of the fractionation tower 300 are respectively provided with a top circulation pump, a middle circulation pump and a bottom circulation pump, each circulation pump is used to inject circulating liquid into the fractionation tower 300 to adjust the temperature of the area.

[0142] Preferably, the fractionating tower 300 is configured from bottom to top with a bottom circulating oil system, a heavy wax oil system, a light wax oil stripping tower system, a mid-section reflux system, a diesel system, a top reflux system, and a top gas phase extraction system to precisely control the temperature gradient of each section and ensure efficient product separation. The following is a detailed description of the configuration and its functions:

[0143] 1. Tower bottom circulating oil system

[0144] Composition: Contains tower bottom circulation pump.

[0145] Function: Regulate the heat balance of the entire fractionating tower 300 through circulating oil, maintain the bottom temperature between 320-380°C, and ensure optimal operating conditions for the heavy wax oil section.

[0146] 2. Heavy wax oil system

[0147] Composition: including heavy wax oil pump 360.

[0148] Function: A portion of the heavy wax oil is transported out as a product, and the other portion is refluxed into the fractionation tower 300 to help maintain specific temperature and pressure conditions while improving the quality of the heavy wax oil.

[0149] 3. Light wax oil stripping tower system

[0150] Composition: It consists of a light wax stripping tower 350 and a light wax oil pump 351.

[0151] Function: Use stripping steam to remove light components from light wax oil. These light components are refluxed into the fractionation tower 300, while the treated light wax oil is transported outward through the light wax oil pump 351 to ensure that the flash point of the light wax oil is ≥65℃, thereby improving its safety and storage stability.

[0152] 4. Mid-section reflux system

[0153] Composition: A middle section pump 320 is provided.

[0154] Function: Used to inject mid-section reflux liquid with a temperature not exceeding 190°C to adjust the fractionation efficiency between diesel and light wax oil and optimize the product quality of both.

[0155] 5. Diesel system

[0156] Composition: Equipped with diesel pump 340.

[0157] Function: A portion of the diesel is transported out as a product, while the other portion is refluxed into the fractionation tower 300 to maintain the optimal operating conditions of the diesel section and ensure that the extraction temperature of the diesel fraction is within the range of 170-220°C.

[0158] 6. Top circulation reflux system

[0159] Composition: Equipped with a top circulation pump 310.

[0160] Function: Inject top circulation reflux liquid with a temperature not exceeding 120℃ into the top section of the tower, dynamically adjust the top temperature to maintain between 80-120℃, and ensure the effective separation of rich gas and naphtha.

[0161] 7. Tower top gas phase extraction system

[0162] Composition: Connected to the top of the fractionation tower 300 through a transfer line.

[0163] Function: Control the tower top pressure at 0.06-0.18MPa to extract rich gas and naphtha, ensuring efficient separation and collection of gas components.

[0164] Preferably, each coke drum 100 is provided with an injection line quick-cut valve and a steam purge valve, wherein:

[0165] The injection line quick-cut valve is used to control the injection of the mixture of ethylene butter and diesel oil, and can quickly open or close the inflow of the mixture to achieve switching between different coke drums 100.

[0166] The steam purge valve is used to perform steam purge on the interior of the original coke drum 100 when the coke drum 100 is switched to prevent the occurrence of coking.

[0167] The technical means disclosed in the solutions of the present invention are not limited to the technical means disclosed in the above technical means, but also include technical solutions composed of any combination of the above technical features. The above is a specific embodiment of the present invention. It should be noted that for those skilled in the art, without departing from the principles of the present invention, various improvements and modifications can be made, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

[0168] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0169] In addition, in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly defined. The terms "connected", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0170] The technical solutions between the various embodiments of the present invention can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0171] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for recycling ethylene butter, characterized in that: include: S1. Mixing ethylene grease and diesel waste oil and storing them in a tank in a tank farm; S2. The mixed liquid in the tank in the tank area is pumped to the special blind cover on the top of the coke drum. The special blind cover extends 100-500mm into the coke drum to inject the mixed liquid into the low gas velocity area in the coke drum; S3. In the coke drum, the mixed liquid contacts and the high-temperature oil and gas to generate polymer and light cracked gas. The polymer settles to the coke layer of the coke drum, and the light cracked gas enters the fractionation tower along with the oil and gas in the coke drum. S4. The cracked gas is fractionated in a fractionating tower to obtain rich gas, naphtha, coking diesel and coking wax oil.

2. The ethylene butter recycling method according to claim 1, characterized in that: In step S1, the proportion of diesel oil in the mixed liquid is 20%-40%.

3. The ethylene butter recycling method according to claim 1, characterized in that: In step S3, the system pressure of the coke drum is set to 0.10 MPa-0.15 MPa, and the temperature inside the coke drum is set to 415-420° C., so that the mixed liquid contacts and the high-temperature oil and gas in the coke drum to be cracked.

4. The ethylene butter recycling method according to claim 1, characterized in that: In step S3, a venting tower is also included, which receives hot heavy wax oil input from the outside, and the bottom of the venting tower outputs quenching oil to the outlet pipeline at the top of the coke tower, and the light cracked gas and oil gas to be output to the distillation tower are cooled by the quenching oil.

5. The ethylene butter recycling method according to claim 4, characterized in that: The gas phase output from the top of the vent tower is separated into dirty oil, acidic water and gas by a three-phase separator and transported out separately; Part of the quenching oil output from the bottom of the vent tower passes through the filter, the vent bottom pump, and the cooling water tank in sequence and then flows back to the top of the vent tower to maintain the liquid phase temperature in the vent tower.

6. The ethylene butter recycling method according to claim 1, characterized in that: In step S4, a temperature gradient is established in the fractionation tower and the fractionation tower is divided into a heavy wax oil section, a light wax oil section, a diesel section, and a gas-rich section from bottom to top, wherein: Gas-rich section products: extract warm gas and naphtha, and control the tower top pressure at 0.06-0.18MPa; Diesel section products: extract diesel fraction with a temperature of 170-220℃; Light wax oil products: extraction temperature of light wax oil is 200-280℃; Heavy wax oil section products: heavy wax oil with extraction temperature of 325-375℃.

7. The ethylene butter recycling method according to claim 6, characterized in that: In step S4, the following systems are configured from bottom to top in the fractionating tower and are used to control the temperature gradient: Tower bottom circulating oil system: used to maintain the tower bottom temperature at 320-380℃ and adjust the thermal balance of the distillation tower through circulating oil; Heavy wax oil system: control the heavy wax oil extraction temperature at 325-375℃; Light wax oil stripper system: removes light components through stripping steam to ensure that the flash point of light wax oil is ≥65℃; Mid-section reflux system: located between the diesel section and the light wax oil section, used to inject mid-section reflux liquid with a temperature of ≤190°C to adjust the fractionation efficiency of diesel and light wax oil; Diesel system: control the extraction temperature of diesel fraction at 170-220℃; Top circulation reflux system: inject top circulation reflux liquid with a temperature of ≤120℃ into the top section of the tower, and dynamically adjust the top temperature to maintain at 80-120℃; Tower top gas phase extraction system: control the tower top pressure to 0.06-0.18MPa, extract rich gas and naphtha.

8. The ethylene butter recycling method according to claim 1, characterized in that: After step S4, the method further includes: S5. Regularly switch the ethylene butter injection to the new coke tower according to the coking cycle of the coke tower. When switching, close the injection line quick-cut valve of the original coke tower to stop injecting the mixed liquid, and open the steam purge valve of the original coke tower to allow anti-coking steam to pass.

9. The ethylene butter recycling method according to claim 8, characterized in that: The specific switching operation in step S5 includes: S51. Confirm that the four-way valve has been switched to the new coke drum, close the quick-cut valve of the original coke drum injection line, and start the new coke drum injection process; S52. Close the steam purge valve behind the quick-cut valve of the new coke drum injection line, open the valve in front of the quick-cut valve of the new coke drum injection line, open the quick-cut valve of the new coke drum injection line, and monitor the temperature and pressure at the top of the new coke drum; S53. Close the quick-cut valve and the front hand valve of the original coke drum injection line, open the steam purge valve of the original coke drum injection line, and pass anti-coking steam; S54. According to the pressure and top temperature of the new coke tower, slowly fully open the front hand valve of the quick-cut valve of the injection line of the new coke tower.

10. The ethylene butter recycling method according to claim 8, characterized in that: In step S5, the steam injection rate into the original coke drum is 200-500 kg / h, and the purge is continued for 8-12 minutes.

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