Coking tower oil switching valve and feeding operation method thereof

Abstract

The invention discloses an oil switching plug valve and a reactor feeding operation method thereof. The oil switching valve is a three-way plug valve and is provided with a valve body, a plug cock, a gas purging connector, a valve cover, a valve rod, packing, a packing gland and a lifting executing mechanism. The three-way plug valve is provided with two oil inlets and an oil outlet, the two oil inlets are located on the side portion of the valve body, the oil outlet is located at the bottom of the valve body, and a fixed included angle is formed between the two oil inlets. An L-shaped medium runner is arranged in the valve element, and an inlet of the medium runner is located in the side face of the valve element. The oil material switching valve can be used for sequentially and alternately feeding two different oil materials into the reactors, the device takes two or more reactors as a group, each reactor adopts an independent oil material switching valve for switching feeding, and the feeding reaction and other operations of the reactors are completed according to the operation cycle of the device and the continuous production requirements of the process.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, specifically relating to an oil switching valve used in a delayed coking unit. Background Technology

[0002] In the typical process flow of a delayed coking unit in an oil refinery, an oil switching valve is usually installed at the junction of the feed pipes between every two coking towers. This oil switching valve is typically a four-way valve, with one conventional four-way valve usually having one oil inlet and three oil outlets. It is used to switch the high-temperature oil from the upstream heater, allowing the oil to alternately enter the two coking towers. This ensures that while one coking tower is producing coke, the other one or two coking towers are undergoing preheating, cooling, hydraulic decoking, pressure testing, and tower warming operations, thus guaranteeing continuous production of the delayed coking unit.

[0003] For delayed coking unit feeding systems or similar chemical new material process units that include two or more feedstocks, in order to allow the two or more feedstocks to enter each coke tower sequentially, according to conventional delayed coking processes, each traditional four-way valve has only one feedstock inlet, and each feedstock requires at least one traditional four-way valve. When two or more feedstocks are used, to allow each coke tower to alternately feed and delay the coking reaction, each coke tower requires at least two or more feedstock switching valves. For production series with two or more coke towers as a group, each coke tower needs to share two or more traditional four-way valves with one or more other coke towers. Thus, due to the limited structure of traditional four-way valves with only three feedstock outlets, when the number of coke towers in a series with two or more feedstocks exceeds three, three feedstock outlets are insufficient, and traditional four-way valves are no longer suitable for applications with more than three coke towers.

[0004] On the other hand, when two or more coking towers are set up for two or more types of feed, two or more four-way valves are required for the two or more types of oil feed. In addition, two or more feed pipes from the outlets of two or more four-way valves are connected in parallel on the feed pipe to the feed inlet of the coking tower in order to realize the switching of two or more types of oil feed.

[0005] Taking two types of oil feed as an example, at least two traditional four-way valves are needed to feed two or more coking towers alternately. In addition, two feed pipes from the outlets of the two traditional four-way valves are connected in parallel on the feed pipe to the feed inlet of the coking tower to achieve the alternate feeding of the two different oils.

[0006] Thus, for two or more feedstocks, each coking tower requires two or more conventional four-way valves connected in parallel to feed the feeds alternately. Since the pressure and temperature conditions for delayed coking reactions differ between the two or more feedstocks, switching from one feedstock from the outlet of a different conventional four-way valve to another can cause pressure and temperature fluctuations. This can impact the entire coking tower feeding system and its upstream processes, leading to pressure and temperature fluctuations such as those in the heating furnace (requiring control adjustments) and the radiant feed pump outlet pressure.

[0007] To accommodate pressure fluctuations or temperature changes in the coke tower feeding system, it is necessary to adopt corresponding design schemes or measures in the oil feeding system. For example, the outlet pipeline of the radiant feed pump may adopt a system pipeline design with an outlet + reflux regulating valve, or a design scheme with variable frequency speed control for the radiant feed pump. This not only complicates the operation of the coke tower feeding system, but also requires parallel connection of oil feed pipelines from the outlets of two or more traditional four-way valves in the relatively small space at the bottom of the coke tower. The more types of feed, the more traditional four-way valves and feed pipelines need to be installed in parallel.

[0008] The feed temperature of coke tower oil is often around 500℃. Under such high-temperature conditions, the parallel connection of oil switching valves, oil isolation valves, and high-temperature feed pipelines in the limited space at the bottom of the coke tower poses certain difficulties for pipeline layout and design. Furthermore, the switching between different operating conditions of the coke tower and its feed system can easily cause pressure fluctuations and temperature changes, adversely affecting the operation of upstream process systems, including heating furnaces and radiant feed pumps. The design of these systems may become more complex and susceptible to adverse effects from pressure fluctuations and temperature changes. This not only increases the initial investment cost, but also makes the upstream systems more vulnerable to pressure fluctuations, causing pressure shocks and vibrations. This can easily lead to damage and leakage of related pipelines, fittings, and valves under pressure shocks and vibrations, thus negatively impacting the long-term stable operation of the unit. It also makes the operation of the entire unit's oil switching valve-related system pipelines more complex, reduces operational reliability, and increases maintenance volume and costs. Summary of the Invention

[0009] This invention provides a coking tower oil switching valve and its feeding method to solve the problem of feeding operation methods for delayed coking units that require alternating feeding of two types of oils into the coking tower, or similar feeding operation methods for coking towers of new chemical materials. It also overcomes the problems inherent in existing technologies that use traditional four-way valves, which involve numerous parallel traditional oil switching valves in the coking tower feeding system, numerous parallel pipelines in the coking tower feeding pipeline system, complex and difficult pipeline system design, and pressure fluctuations and temperature changes in the pipeline system that are easily caused when different oil switching valves switch the feed into the coking tower, potentially affecting the upstream feeding system of the coking tower.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] A coke tower oil switching valve is characterized in that: the oil switching valve is a three-way plug valve, comprising a valve body, a plug, a gas purging port, packing, a valve cover, a valve stem, a support, a packing gland, a lifting actuator, and a rotating actuator; the valve stem is mechanically fixedly connected to the plug; the oil switching valve has two oil inlets and one oil outlet, with both oil inlets located on the side of the valve body and the oil outlet located at the bottom of the valve body, the two oil inlets being adjacent to each other on the side of the valve body; the plug has an L-shaped medium flow channel inside, with the medium flow channel inlet located on the side of the plug and the medium flow channel outlet located at the bottom of the plug. The lifting actuator and the rotating actuator are mounted on the valve body.

[0012] The present invention provides a coke tower oil switching valve, which is further characterized in that: feed from any oil inlet will be discharged from one oil outlet of the valve.

[0013] The present invention provides a coke tower oil switching valve, which is further characterized in that: the two oil inlets are adjacent to each other and form a fixed angle between them, which can be selected between 90° and 120°.

[0014] The present invention discloses a coke tower oil switching valve, which is further characterized in that: the switching operation of the valve firstly lifts the cock through a lifting actuator, so that the cock is separated from the valve body; secondly, the valve stem and the cock are driven to rotate through a rotary actuator, and each switching rotation has a certain fixed angle, so that the oil feed can be switched from one oil inlet to another; then the cock is driven to descend onto the valve body through the lifting actuator, completing the switching operation from one oil inlet to another.

[0015] The present invention discloses a coke tower oil switching valve, further characterized in that: the plug is located in the inner cavity of the valve body, and the plug is an inverted truncated cone with a cone angle of 15 to 30 degrees. A plug medium flow channel inlet sealing surface is provided on the outer surface of the plug around the medium channel inlet, which is a convex annular sealing surface on the conical surface of the plug.

[0016] This invention discloses a coke tower oil switching valve, further characterized in that: an oil inlet sealing surface is provided on the inner side of the valve body around each oil inlet, which is a concave annular sealing surface on the conical surface inside the valve body. The sealing surface on the plug contacts any oil inlet sealing surface on the valve body, and the two surfaces cooperate to form a seal.

[0017] During valve switching operations, the valve cock is first raised by the lifting actuator, causing the cock's sealing surface to disengage from the sealing surface of any oil inlet on the valve body. Next, the valve stem and cock are rotated by a fixed angle via the rotary actuator, completing the switch from one oil inlet to another. Then, the valve cock is lowered by the lifting actuator, causing the cock's sealing surface to press against the sealing surface of the other oil inlet on the valve body, forming a seal.

[0018] The present invention provides a coke tower oil switching valve, which is further characterized in that: the plug valve is provided with a gas purging interface, the gas purging interface is connected to a gas purging channel, and the outlet of each gas purging channel is located on the lower surface of the valve cover, on the inner side of the valve body, and at the packing.

[0019] This invention also protects a coke tower feeding operation method using the aforementioned oil switching valve, and a coke tower feeding operation method for a similar chemical new materials plant.

[0020] A method for feeding coke towers is disclosed. The apparatus comprises n coke towers as a production series, with each tower independently using an oil switching valve as described above. The method is characterized by: a one-to-one correspondence between coke towers and oil switching valves; each coke tower using its own independent four-way oil switching valve; the oil switching valve being a three-way plug valve, with its two oil inlets connected to two upstream feed branch pipes, and its oil outlet connected to a downstream feed pipe and a feed shut-off valve; two different oils entering the oil switching valve via the first and second main feed pipes, then through the two feed branch pipes, and then through the oil switching valve to switch the feed, before sequentially and alternately entering the corresponding coke tower via the outlet shut-off valve and the oil feed pipe. The number of n coke towers is 2-15.

[0021] A method for feeding coke towers, characterized in that: each coke tower is equipped with its own independent oil and gas pressure control valve on the oil and gas pipeline at the top of the tower, which is used to adjust the coke tower pressure to meet the different coke tower operating pressure requirements when different oils are fed.

[0022] A method for feeding a coke tower, further characterized in that: a bypass pipe with a bypass isolation valve is connected in parallel to the first feed main pipe and connected to the top of the coke tower for start-up and tower warming.

[0023] A method for feeding coke towers, further characterized in that: feed shut-off valves can be installed on the first and second feed mains leading to the final coke tower, respectively, with the feed shut-off valves installed close to the first and second feed branch pipes. Feed shut-off valves can also be installed on the first and second feed mains leading to the final coke tower, respectively, with the feed shut-off valves installed close to the feed branch pipe of the coke tower adjacent to the final coke tower. For a feeding system of three coke towers for two types of oilseeds, the feed shut-off valves are installed close to the first and second feed branch pipes of the second coke tower.

[0024] A method for feeding coke towers, further characterized in that: for a feeding method in which two types of oils are fed into three coke towers respectively, the oils are switched in three stages during continuous production:

[0025] The first stage is the feeding operation of raw material 1 into the coke tower. By switching the oil switching valve, the raw material 1 of the coke tower enters the coke tower through the first feed main pipe, the first feed branch pipe, the oil switching valve, the feed pipeline and the feed isolation valve on it, and the reaction occurs at the same time as feeding.

[0026] In the second stage, the oil feed is switched from coke tower feed 1 to coke tower feed 2 by switching the oil feed switching valve. The coke tower feed 2 enters the coke tower through the second feed main pipe, the second feed branch pipe, the oil feed switching valve, the feed pipeline and the feed isolation valve on it, and the reaction occurs at the same time as the feed.

[0027] In the third stage, according to the unit's operating cycle and the requirements for continuous production, the feeding is completed alternately through the corresponding oil switching valve of each coke tower in the two stages mentioned above.

[0028] The two feedstocks react continuously. During the feed reaction stage in the coking tower, the oil and gas from the top of the tower are transported via pipeline to the downstream fractionation system for further fractionation. At this point, the top of the coking tower is connected to the fractionation system. During the preheating, cooling, hydraulic decoking, and pressure testing stages in the coking tower, the top of the tower is disconnected from the fractionation system and removed from the reaction-fractionation system. The coking material inside the tower is then discharged from the bottom of the tower into a coke storage tank or dehydration chamber through hydraulic decoking. This process is repeated continuously.

[0029] When using n coking towers, the coking feed can be fed into any one of the n coking towers in stages according to the first and second stages described above. While (nx) coking towers are feeding and reacting, the other x coking towers are performing other operations after the feed reaction, such as preheating, cooling, hydraulic decoking, pressure testing, and tower warming. The number of coking towers n can be greater than or less than 3, but to ensure continuous production, it is usually greater than or equal to 2. Taking two different feeds fed into 3 coking towers as an example, the coking towers are grouped into a series of 3. While feedstock 1 is being fed and reacted in one coking tower, feedstock 2 is being fed and reacted in one of the other two coking towers, while the other tower is performing other operations after the feed reaction.

[0030] The oil switching valve and feeding operation method of the present invention can be used not only in the coke tower of delayed coking unit, but also in other feeding systems in the petrochemical and chemical fields.

[0031] The beneficial effects of using this invention are as follows:

[0032] The oil switching valve proposed in this invention adopts a three-way plug valve scheme to replace the traditional four-way valve in conventional delayed coking units, which can meet the process operation requirements of feeding two different oils into two or more coking towers in sequence.

[0033] This invention proposes an oil switching valve and its corresponding coke tower feeding method. The coke tower and the oil switching valve are in a one-to-one correspondence; one oil switching valve is used only for one coke tower. Compared to conventional designs, where each coke tower uses two or more traditional four-way valves for alternating feeding, this method is less susceptible to pressure fluctuations and temperature changes caused by different pressures and temperatures of the oil feed to different coke towers. The pressure and temperature of the feeding system for each coke tower can be adjusted to adapt to different feed conditions, thereby reducing the impact on the coke tower feeding system and its upstream related feeding systems.

[0034] This invention proposes an oil switching valve and its coke tower feeding operation method, which enables two different oils to enter the coke tower sequentially or alternately. It can meet the feeding operation methods of delayed coking units where two different oils are fed alternately, or similar feeding operation methods. The feeding combinations are diverse, and the operation is flexible and adaptable. It can be adapted to various new petrochemical processes and new material coke tower feeding processing methods similar to this method.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The accompanying drawings and specific embodiments do not limit the scope of protection claimed by the present invention. Attached Figure Description

[0036] Figure 1 The feeding process for two types of oilseeds and three coking towers is simplified. Figure 1 ;

[0037] Figure 2 The feeding process for two types of oilseeds and three coking towers is simplified. Figure 2 ;

[0038] Figure 3 This is a simplified cross-sectional view of a three-way plug valve.

[0039] Figure 4 This is a simplified top view schematic diagram of a three-way plug valve;

[0040] Figure 5 This is a simplified sectional view of a three-way plug valve.

[0041] The attached diagram is labeled as follows: 1-valve body, 2-cocking valve, 3-gas purging port, 4-valve stem packing, 5-oil inlet, 6-oil outlet, 7-valve cover, 8-valve stem, 9-bracket, 10-packing gland, 11-lifting actuator, 12-rotary actuator, 200-bypass isolation valve, 201-first feed main, 202-second feed main, 203-bypass pipe, 204A / B / C-coke tower A / B / C, 205A / B / C-oil inlet pipe A / B / C, 206A / B / C - First feed branch pipe A / B / C, 207A / B / C - Second feed branch pipe A / B / C, 208A / B / C - Oil switching valve A / B / C, 209A / B / C - Oil isolation valve A / B / C, 210A / B / C - Oil-gas pressure control valve A / B / C, 211 - First feed main pipe isolation valve, 212 - Second feed main pipe isolation valve, 213A / B / C - Oil-gas branch pipe A / B / C, 214A / B / C - Oil-gas isolation valve A / B / C, 215 - Oil-gas ring valve, 216 - Oil-gas main pipe. Detailed Implementation

[0042] The implementation of the technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0043] As attached Figure 1 To the attached Figure 5As shown. The oil switching valve is a three-way plug valve. The valve includes a valve body 1, a plug 2, a gas purging port 3, packing 4, a valve cover 7, a valve stem 8, a bracket 9, a packing gland 10, a lifting actuator 11, and a rotating actuator 12. The valve stem 8 is mechanically fixed to the plug 2. The oil switching valve has two oil inlets 5 and one oil outlet 6. Both oil inlets 5 are located on the side of the valve body 1, and the oil outlet 6 is located at the bottom of the valve body 1. The two oil inlets 5 are adjacent to each other, forming a fixed angle and distributed along the side of the valve body 1. The fixed angle can be selected between 90° and 120°. The plug 2 has an L-shaped medium flow channel inside. The medium flow channel inlet is located on the side of the plug 2, and the medium flow channel outlet is located at the bottom of the plug 2. The lifting actuator 11 and the rotating actuator 12 are mounted on the valve body. The centerline of the valve stem 8 is perpendicular to the horizontal plane formed by the centerlines of the two oil inlets 5. The valve lifting and rotating actuators 11 and 12 can be existing electric, pneumatic, or hydraulic actuators (preferably electric actuators), and may include a backup manual actuator. The valve switching operation first involves lifting the stopcock 2 via the lifting actuator 11, disengaging it from the valve body 1. Next, the rotating actuator 12 drives the valve stem 8 and the stopcock 2 to rotate, with each rotation at a fixed angle, allowing the oil feed to switch from one oil inlet 5 to another. Then, the lifting actuator 11 drives the stopcock 2 to descend onto the valve body 1, completing the switching operation from one oil inlet 5 to another. Regardless of which oil inlet 5 is used for feeding, the oil is discharged from one oil outlet 6 of the valve.

[0044] The oil switching valve is a three-way plug valve. Plug 2 is located inside the valve body 1. Plug 2 is an inverted truncated cone with a cone angle of 15-30 degrees. A medium flow channel inlet sealing surface, a convex annular sealing surface on the conical surface of plug 2, is provided around the medium channel inlet on the outer surface of plug 2. An oil inlet sealing surface, a concave annular sealing surface on the inner conical surface of valve body 1, is provided around each oil inlet 5 on the inner side of the valve body 1. The sealing surfaces on plug 2 and any oil inlet sealing surface on the valve body are in contact with each other, forming a seal. The sealing surfaces are generally hard metal sealing surfaces. The metal can be surface-hardened using methods such as chrome plating or high-temperature hard alloy overlay welding, which can resist wear from solid particles such as coke powder. The materials of valve body 1, valve cover 7, valve stem 8, and plug 2 can be high-temperature resistant materials such as chromium alloy steel or austenitic stainless steel. During valve switching operation, firstly, the lifting actuator 11 raises the stopcock 2, causing the sealing surface of the stopcock 2 to disengage from the sealing surface of any oil inlet on the valve body 1. Secondly, the rotating actuator 12 drives the valve stem 8 to rotate the stopcock 2 by a fixed angle, completing the switching from one oil inlet 5 to another. Then, the lifting actuator 11 drives the stopcock 2 to descend, causing the sealing surface of the stopcock 2 to press against the sealing surface of another oil inlet 5 on the valve body 1, forming a seal.

[0045] The oil switching valve is a three-way plug valve, which has several gas purging ports 3 connected to gas purging channels. The outlets of each gas purging channel are located on the lower surface of the valve cover 7, the inner side of the valve body 1, and the packing 4, respectively. During valve operation, gas enters the gas purging ports 3 and flows out from the outlets of each gas purging channel, entering the portion of the valve body 1 between the plug 2 and the valve cover 7, the inner side of the valve body 1 between the outer side of the plug 2, and the packing 4. This prevents coke-containing oil from entering these areas, thus preventing coking and coke leakage. Steam or other suitable gases can be used.

[0046] After the oil switching valve is in place, gas vapor cannot enter the area between the sealing surfaces of the contacting plug 2 and valve body 1 (because it is a hard metal seal), nor can it enter the area between the packing 4 and valve stem 8. Therefore, gas vapor cannot enter the oil pipeline and flow away, reducing the amount of gas vapor used. In the event of a slight leak at the aforementioned contacting sealing surfaces, the gas vapor can prevent coke-containing oil from entering the inner cavity of valve body 1. Even if coke-containing oil does enter the inner cavity of valve body 1, the gas vapor can prevent it from leaking out of the valve through the packing 4.

[0047] The unit consists of two or more coking towers as a group, with each coking tower using an independent oil switching valve to change the feed. There is a one-to-one correspondence between coking towers and oil switching valves. For example... Figure 1Taking the feed process of three coking towers with two types of oil as an example, the three coking towers are grouped together. Each coking tower 204A, 204B, or 204C uses its own independent oil switching valve 208A, 208B, or 208C to switch the oil. There is a one-to-one correspondence between coking towers 204A / B / C and oil switching valves 208A / B / C. One oil switching valve 208A / B / C is used only for one coking tower 204A / B / C.

[0048] The oil switching valves 208A / B / C are three-way plug valves. These valves have two oil inlets 5 and one oil outlet 6. The two oil inlets 5 are located on the side of the valve body, and the oil outlet 6 is located at the bottom of the valve body. This structural feature allows the valve to be used in coke tower feeding methods where two oils are fed alternately, or similar feeding processing methods. Taking coke tower 204A as an example, one oil switching valve 208A is provided. Its two oil inlets 5 are connected to two upstream feed branch pipes 206A and 207A, respectively, and its oil outlet 6 is connected to a downstream feed pipe 205A and a feed shut-off valve 209A above it. Two different types of oil are fed through the first and second feed mains 201 and 202, respectively, and then through two feed branch pipes 206A and 207A to enter the oil switching valve 208A. The feed is switched by the oil switching valve 208A, and then alternately enters the corresponding coke tower 204A through the discharge isolation valve 209A and the oil feed pipe 205A.

[0049] Two different oils can be alternately fed into the corresponding coke towers 204A / B / C via oil switching valves 208A / B / C, which correspond one-to-one with the oils feeding towers 204A / B / C. In addition, a bypass pipe 203 with a bypass isolation valve 200 is connected in parallel to the first feed main pipe 201, connecting to the top of the coke towers for start-up and warm-up. Each coke tower 204A / B / C has its own independent oil and gas pressure control valve 210A / B / C on its top oil and gas pipeline, used to regulate the pressure of each coke tower 204A / B / C to meet the different operating pressure requirements of the coke towers when different oils are fed.

[0050] The oil and gas at the top of the coke towers are discharged to the unit's fractionation system via oil and gas pipelines and valves. Each coke tower has an independent oil and gas discharge route at the top. Taking coke tower 204A as an example, the oil and gas at the top of the tower is discharged to the unit's fractionation system via the top oil and gas branch pipe 213A and the oil and gas pressure control valve 210A and oil and gas isolation valve 214A installed thereon, and then via the top oil and gas main pipe 216 and the oil and gas ring valve 215 installed thereon. Each coke tower 204A, 204B, or 204C is equipped with its own oil and gas pressure control valve 210A, 210B, or 210C on the corresponding top oil and gas branch pipe 213A, 213B, or 213C, which is used to regulate the pressure of each coke tower 204A, 204B, or 204C to meet the different coke tower operating pressure requirements when different oil feeds are used.

[0051] As an alternative, in cases such as Figure 1 Based on the aforementioned scheme, feed shut-off valves 211 and 212 can be installed on the first and second feed mains 201 and 202 leading to the final coke tower 204C, respectively. Feed shut-off valves 211 and 212 are installed near the first and second feed branch pipes 206C and 207C, respectively. Figure 2 As shown.

[0052] For the coking tower feeding method where two types of oil are fed into three coking towers respectively, the oil is switched in three stages during continuous production:

[0053] The first stage involves feeding coke tower feedstock 1 into coke towers 204A / B / C. Through the switching of oil-fuel switching valves 208A / B / C, coke tower feedstock 1 enters coke towers 204A / B / C via the first feed main 201, first feed branch 206A / B / C, oil-fuel switching valves 208A / B / C, feed pipes 205A / B / C, and their feed shut-off valves 209A / B / C, as described above. A reaction occurs simultaneously with the feeding. At this time, oil-fuel switching valves 208A / B / C are three-way plug valves.

[0054] In the second stage, the oil feed is switched from coke tower feed 1 to coke tower feed 2 by switching the oil switching valve 208A / B / C. The coke tower feed 2 then enters the coke tower 204A / B / C through the second feed main pipe 202, the second feed branch pipe 207A / B / C, the oil switching valve 208A / B / C, the feed pipe 205A / B / C and the feed isolation valve 209A / B / C on it, as described above. The reaction occurs at the same time as the feed is fed.

[0055] In the third stage, according to the unit's operating cycle and continuous production requirements, the feeding is carried out alternately through the corresponding oil switching valves 208A / B / C of each coke tower 204A / B / C, following the two steps mentioned above. While one of the three coke towers 204A / B / C is receiving coke tower feedstock 1 for reaction, one of the other two coke towers 204A / B / C is receiving coke tower feedstock 2 for reaction, and the other coke tower is performing other operations after the feed reaction is completed, such as preheating, cooling, hydraulic decoking, pressure testing, and tower warming.

[0056] Following this pattern, based on the unit's operating cycle and continuous production requirements, the two feedstocks are sequentially and alternately fed and reacted in coke towers 204A / B / C according to the three operating stages described above. Then, preheating, cooling, hydraulic decoking, pressure testing, and tower warming are sequentially and alternately performed. The reaction of the two oil feedstocks proceeds uninterrupted. While the coke tower is in the feeding reaction stage, the oil and gas at the top of the coke tower are transported via oil and gas pipelines to the downstream fractionation system for further fractionation. At this time, the top of the coke tower is connected to the fractionation system. During the preheating, cooling, hydraulic decoking, and pressure testing stages, the top of the coke tower is disconnected from the fractionation system and removed from the reaction-fractionation system. The coking material inside the coke tower is discharged from the bottom of the coke tower into a coke storage tank or dehydration chamber after hydraulic decoking. The above stages are continuously cyclical.

[0057] Depending on the unit's operating cycle and continuous production requirements, multiple coking towers can be installed for two different oil feedstocks; for example, n coking towers can be used. Figure 1 and Figure 2 The feeding method for the coke towers is similar. The coke tower feed can be divided into time slots, following the first and second stages described in the feeding method of feeding the two types of oil into three coke towers respectively, sequentially entering any one of the n coke towers. While (nx) coke towers are feeding and reacting, the other x coke towers undergo other operations after the feed reaction is completed, such as preheating, cooling, hydraulic decoking, pressure testing, and tower warming. The number of coke towers n can be greater than or less than 3, but to ensure continuous production, it is usually required to be greater than or equal to 2. The feeding method and feeding operation stages are similar to the methods described above.

[0058] The above are merely typical embodiments of the present invention. It should be noted that those skilled in the art can make several improvements or substitutions without departing from the principles described in the present invention, and these improvements or substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A coke tower oil switching valve, characterized in that: The oil switching valve is a three-way plug valve, comprising a valve body, plug, gas purging port, packing, valve cover, valve stem, bracket, packing gland, lifting actuator, and rotating actuator. The valve stem is mechanically fixed to the plug. The oil switching valve has two oil inlets and one oil outlet. Both oil inlets are located on the side of the valve body, and the oil outlet is located at the bottom of the valve body. The two oil inlets are adjacent to each other on the side of the valve body. The plug has an L-shaped medium flow channel inside, with the medium flow channel inlet located on the side of the plug and the medium flow channel outlet located at the bottom of the plug. The lifting actuator and rotating actuator are mounted on the valve body.

2. The coke tower oil switching valve according to claim 1, characterized in that: The two oil inlets are adjacent to each other and form a fixed angle of 90° to 120° between them.

3. The coke tower oil switching valve according to claim 1, characterized in that: Feeding from any oil inlet results in discharging from one oil outlet of the valve.

4. The coke tower oil switching valve according to claim 1, characterized in that: The valve switching operation first involves lifting the cock via a lifting actuator to disengage the cock from the valve body; Secondly, the valve stem and the valve plug are driven to rotate by the rotary actuator. Each rotation is at a fixed angle, allowing the oil feed to switch from one oil inlet to another. Then, the valve plug is driven to descend onto the valve body by the lifting actuator, completing the switching operation from one oil inlet to another.

5. The coke tower oil switching valve according to claim 1, characterized in that: The stopcock is located in the inner cavity of the valve body. The stopcock is an inverted truncated cone with a cone angle of 15 to 30 degrees. A stopcock medium flow channel inlet sealing surface is provided on the outer surface of the stopcock around the medium channel inlet. It is an outwardly convex annular sealing surface on the cone surface of the stopcock.

6. The coke tower oil switching valve according to claim 1, characterized in that: A valve body oil inlet sealing surface is provided around each oil inlet on the inner side of the valve body. It is an inwardly concave annular sealing surface on the conical surface inside the valve body. The sealing surface on the plug contacts any oil inlet sealing surface on the valve body, and the two are opposite to each other and cooperate to form a seal.

7. The coke tower oil switching valve according to claim 1, characterized in that: The plug valve is equipped with a gas purging port, which is connected to a gas purging channel. The outlets of each gas purging channel are located on the lower surface of the valve cover, the inner side of the valve body, and the packing, respectively.

8. A method for feeding coke towers, comprising n coke towers as a group, wherein each coke tower uses an oil-feed switching valve as described in sections 1-7 to switch the feed, characterized in that: Each coke tower is paired with an oil switching valve; each coke tower uses its own independent oil switching valve to switch feeds; the oil switching valve is a three-way plug valve, with its two oil inlets connected to two upstream feed branch pipes, and its oil outlet connected to a downstream feed pipe and a feed shut-off valve thereon; two different oils enter the oil switching valve through the first and second feed mains, then through the two feed branch pipes, and are switched at the oil switching valve. The oils then pass through the discharge shut-off valve and the oil feed pipe, alternately entering the corresponding coke tower; each coke tower has its own independent oil and gas pressure control valve on the top oil and gas pipeline, used to regulate the coke tower pressure to meet the different coke tower operating pressure requirements when different oils are fed.

9. The method for feeding a coke tower according to claim 8, characterized in that: The number of coke towers is 2-15.

10. The method for feeding a coke tower according to claim 8, characterized in that: For the reactor feeding method where two types of oil are fed into three coking towers respectively, the oil is switched in three stages during continuous production: The first stage is the feeding operation of raw material 1 into the coke tower. By switching the oil switching valve, the raw material 1 of the coke tower enters the coke tower through the first feed main pipe, the first feed branch pipe, the oil switching valve, the feed pipeline and the feed isolation valve on it, and the reaction occurs at the same time as feeding. In the second stage, the oil feed is switched from coke tower feed 1 to coke tower feed 2 by switching the oil feed switching valve. The coke tower feed 2 enters the coke tower through the second feed main pipe, the second feed branch pipe, the oil feed switching valve, the feed pipeline and the feed isolation valve on it, and the reaction occurs at the same time as the feed. In the third stage, according to the unit operation cycle and the requirements of continuous production, the feed is carried out alternately through the corresponding oil switching valve of each coking tower. While the feed reaction of coking tower feed 1 is carried out in one of the other two coking towers, the feed reaction of coking tower feed 2 is carried out in one of the other two coking towers, and the other tower carries out other operations after the feed reaction is completed.

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