阅读说明：本技术 一种延迟焦化装置的油料切换方法与油料切换阀 (Oil switching method and oil switching valve of delayed coking device ) 是由 张欣 杨成炯 张利 石柯 于 2019-01-10 设计创作，主要内容包括：本发明公开了一种延迟焦化装置的油料切换方法与油料切换阀。方法是,三座焦炭塔(7)使用一个油料切换阀(2)切换油料,油料切换阀为五通球阀。切换油料时,来自加热炉的油料经过油料入口管线(1)、从油料切换阀的油料入口进入油料切换阀。然后,油料经过油料切换阀的油料出口和油料出口管线(3)以及旁通管线(5)进入焦炭塔。通过旋转油料切换阀的阀杆和阀芯,为三座焦炭塔切换油料。本发明公开的一种延迟焦化装置的油料切换阀,设有阀体、阀芯、阀盖、阀杆、旋转执行机构等,带有一个油料入口和四个油料出口。一个油料入口位于阀体的底部,四个油料出口位于阀体的侧部。本发明主要用于炼油厂中以三座焦炭塔为一组的延迟焦化装置。(The invention discloses an oil switching method and an oil switching valve of a delayed coking device. The method is that three coke drums (7) use an oil switching valve (2) to switch oil, and the oil switching valve is a five-way ball valve. When the oil is switched, the oil from the heating furnace enters the oil switching valve from the oil inlet of the oil switching valve through the oil inlet pipeline (1). The oil then passes through the oil outlet of the oil switching valve and oil outlet line (3) and bypass line (5) into the coke drum. The oil is switched for the three coke drums by rotating the valve rod and the valve core of the oil switching valve. The invention discloses an oil switching valve of a delayed coking device, which is provided with a valve body, a valve core, a valve cover, a valve rod, a rotary actuating mechanism and the like, and is provided with an oil inlet and four oil outlets. One oil inlet is located at the bottom of the valve body, and four oil outlets are located at the side of the valve body. The invention is mainly used for a delayed coking device which takes three coke drums as a group in an oil refinery.)

1. An oil switching method of a delayed coking device, the delayed coking device takes three coke towers (7) as a group, and is characterized in that: the three coke drums (7) use one oil switching valve (2) to switch oil, the oil switching valve (2) is a five-way ball valve and is provided with a valve rod (18), a valve core (12), one oil inlet (15) and four oil outlets (16), the oil inlet (15) is connected with one oil inlet pipeline (1), one oil outlet (16) is connected with one bypass pipeline (5), the other three oil outlets (16), each oil outlet (16) is connected with one coke drum (7) through one oil outlet pipeline (3), each oil outlet pipeline (3) is provided with one cut-off valve (4), and the bypass pipeline (5) is provided with one bypass valve (6);

when the oil switching valve (2) switches oil, oil from a heating furnace enters an oil inlet pipeline (1) connected with an oil inlet (15) and then enters the oil switching valve (2) from the oil inlet (15), the oil is switched according to three stages when the delayed coking device is continuously produced, the first stage is to rotate a valve rod (18) and a valve core (12) to ensure that the oil enters a coke tower (7) through an oil outlet (16) and an oil outlet pipeline (3) connected with an oil outlet pipeline (3), the oil is subjected to delayed coking reaction at the same time, the second stage is to rotate the valve rod (18) and the valve core (12) to ensure that the oil enters a second coke tower (7) through another oil outlet (16) and an oil outlet pipeline (3) connected with the oil outlet pipeline (3), the oil is subjected to delayed coking reaction at the same time, and the third stage is to ensure that the oil is not coked in the second, and rotating the valve rod (18) and the valve core (12) to enable the oil to enter a third coke tower (7) through a third oil outlet (16) connected with the oil outlet pipeline (3) and the oil outlet pipeline (3), and simultaneously carrying out delayed coking reaction on the oil, wherein the three stages are continuously and circularly carried out in sequence.

2. The method of claim 1, wherein: two or more kinds of oil from two or more oil inlet pipelines (1) of two or more heating furnaces enter one oil inlet pipeline (1) connected with an oil inlet (15) of an oil switching valve (2), are mixed in the oil inlet pipeline (1), enter the oil switching valve (2) from the oil inlet (15), and then enter three coke towers (7) respectively.

3. The method according to claim 1 or 2, characterized in that: and rotating a valve rod (18) and a valve core (12) of the oil switching valve (2) to enable high-temperature oil to enter the bypass pipeline (5) through an oil outlet (16) connected with the bypass pipeline (5), and enter the three coke towers (7) through a tower top pipeline (9) connected with the bypass pipeline (5) to preheat the three coke towers (7) before start-up.

4. The utility model provides a delayed coking unit's oil diverter valve which characterized in that: the oil switching valve (2) is a five-way ball valve and is provided with a valve body (11), a valve core (12), a valve cover (17), a valve rod (18), a filler (14), a filler gland (10) and a rotary actuating mechanism (25), wherein the valve core (12) is positioned in an inner cavity of the valve body (11), the valve rod (18) is fixedly connected with the valve core (12), a valve core channel is arranged inside the valve core (12), an inlet of the valve core channel is positioned at the bottom of the valve core (12), an outlet of the valve core channel is positioned on the outer side surface of the valve core (12), the rotary actuating mechanism (25) is used for controlling the rotation of the valve rod (18) and the valve core (12), the bottom and the side part of the valve body (11) are respectively provided with one or four valve body openings, each valve body opening is provided with a sealing seat (20) and a sealing sleeve (21), each sealing seat (20) is composed of a sealing seat flange, a gap is reserved between the part, close to the sealing seat flange, of the sealing seat center barrel and the sealing sleeve (21), a sealing cavity is formed between the rest of the sealing seat center barrel and the sealing sleeve (21), an elastic element (22) is arranged in the sealing cavity, one end of the elastic element (22) is close to the valve core (12), a sealing ring (23) is arranged between the elastic element and the valve core (12), metal-to-metal elastic hard sealing is formed between the valve core (12) and the sealing ring (23), meanwhile, spherical sealing is achieved, the center hole of the sealing seat (20) at the bottom of the valve body (11) serves as an oil inlet (15) of the oil switching valve (2), and the center hole of the sealing seat (20) at the side of the valve body (11) serves as an.

5. An oil switching valve as claimed in claim 4, wherein: the elastic element (22) is a spring or a bellows.

6. An oil switching valve as claimed in claim 4 or 5, wherein: the oil switching valve (2) is provided with a steam purging connecting pipe (13), the steam purging connecting pipe (13) is connected with a steam purging channel, the steam purging channel is arranged on the valve body (11), the valve cover (17) and the sealing sleeve (21), and outlets of the steam purging channels are respectively positioned on the lower surface of the valve cover (17), the filler (14) and between the sealing seat central cylinder and the sealing sleeve (21) and close to the sealing seat flange.

7. An oil switching valve as claimed in claim 6, wherein: a steam distribution groove (24) is arranged around the part of the central cylinder of the sealing seat, which is close to the flange of the sealing seat, and the outlet of the steam sweeping channel between the part of the central cylinder of the sealing seat, which is close to the flange of the sealing seat, and the sealing sleeve (21) is communicated with the steam distribution groove (24).

8. An oil switching valve as claimed in claim 6 or 7, wherein: the sealing sleeve (21) is cylindrical and is divided into two parts along the axial lead, and the end part of the sealing sleeve (21) close to the sealing seat flange is provided with an annular boss protruding inwards and clamped in a groove on the sealing seat central cylinder close to the sealing seat flange.

9. An oil switching valve as claimed in claim 8, wherein: the sealing surfaces of the valve core (2) and the sealing ring (23) are both provided with chromium coatings or hard alloy layers.

Technical Field

The invention relates to an oil switching method and an oil switching valve of a delayed coking device in an oil refinery. In particular to an oil switching method and an oil switching valve of a delayed coking device with three coke drums as a group.

Background

In the typical process flow of a delayed coker unit in an oil refinery, an oil switching valve is often installed at the junction before every two coke drums. The valve is typically a four-way valve, one valve comprising one oil inlet and three oil outlets. The oil switching valve is used for switching high-temperature oil from the upstream so that the oil alternately enters the two coke drums. This allows one coke drum to be decoked while the other coke drum is being coked, to ensure continuous production in a delayed coker (not shown).

As shown in fig. 1, in a new delayed coking unit, three coke drums 7 are grouped, two oil switching valves 2 (four-way valves) are used to switch oil, two coke drums 7 are fed and coke is formed, one coke drum is stopped and coke is removed. The oil inlet of each oil switching valve 2 is respectively connected with an oil inlet pipeline 1; the two oil outlets are connected with an oil outlet pipeline 3 respectively, and feed to a coke tower 7 through the oil outlet pipeline 3, and simultaneously carry out delayed coking reaction. A cut-off valve 4 is required to be arranged on an oil outlet pipeline 3 connected with an oil outlet, and a logic interlocking protection relation exists between the cut-off valve 4 and the oil switching valve 2 so as to ensure the feeding operation safety of high-temperature oil. When the number of the oil switching valves 2 is two, four cut-off valves 4 are arranged. One oil outlet of each oil switching valve 2 is respectively connected with a bypass pipeline 5, and the bypass pipeline 5 is connected with a tower top pipeline 9 so as to introduce high-temperature oil into a coke tower 7 for preheating before start-up; a bypass line 5 is provided with a bypass valve 6. The two kinds of oil from the heating furnace respectively enter two oil switching valves 2 through two oil inlet pipelines 1 and then respectively enter three coke towers 7. The delayed coking device uses two oil switching valves 2 (four-way valves) to switch the oil, and mainly has the following problems: (1) the number of the oil switching valves is two, the number of the stop valves is four, the number of the bypass valves is two, the equipment investment is increased, and the complexity and difficulty of oil switching operation are increased. (2) The number of the oil outlet pipelines and the bypass pipelines is large, and the workload of connection and arrangement is large. (3) The oil inlets and the oil outlets of the two oil switching valves are respectively connected with the oil inlet pipeline, the oil outlet pipeline and the bypass pipeline through flanges. The possibility of oil leakage is increased due to the large number of flange connections (eight total). The above problems increase the operating and maintenance costs of a delayed coker for long periods of operation.

Disclosure of Invention

The invention aims to provide an oil switching method and an oil switching valve of a delayed coking device, which are used for solving the problems of the prior art caused by more oil switching valves, cut-off valves, bypass valves, oil outlet pipelines and bypass pipelines and more flange connections, and the problem that a single four-way oil switching valve is not suitable for switching feeding for three coke towers.

In order to solve the problems, the invention adopts the technical scheme that: an oil switching method of a delayed coking device, wherein the delayed coking device takes three coke towers as a group, and is characterized in that: the three coke towers use an oil switching valve to switch oil, the oil switching valve is a five-way ball valve and is provided with a valve rod, a valve core, an oil inlet and four oil outlets, the oil inlet is connected with an oil inlet pipeline, one oil outlet is connected with a bypass pipeline, the other three oil outlets are respectively connected with one coke tower through an oil outlet pipeline, each oil outlet pipeline is provided with a cut-off valve, and the bypass pipeline is provided with a bypass valve;

when the oil material switching valve switches the oil material, the oil material from the heating furnace enters an oil material inlet pipeline connected with the oil material inlet and then enters the oil material switching valve from the oil material inlet, the oil material is switched according to three stages when the delayed coking device is continuously produced, in the first stage, the valve rod and the valve core are rotated, the oil material enters a coke tower through an oil material outlet and an oil material outlet pipeline connected with the oil material outlet pipeline, the oil material simultaneously carries out delayed coking reaction, in the second stage, the valve rod and the valve core are rotated, the oil material enters a second coke tower through another oil material outlet and an oil material outlet pipeline connected with the oil material outlet pipeline, the oil material simultaneously carries out delayed coking reaction, in the third stage, the valve rod and the valve core are rotated, the oil material enters a third coke tower through an oil material outlet and an oil material outlet pipeline connected with the oil material outlet pipeline, and the oil material simultaneously, the three stages are continuously and circularly carried out in sequence.

One scheme of the present invention is that two or more kinds of oil from two or more oil inlet pipelines of two or more heating furnaces enter one oil inlet pipeline connected to the oil inlet of the oil switching valve, are mixed in the oil inlet pipeline, enter the oil switching valve from the oil inlet, and then enter three coke towers respectively.

When the three coke towers need to be preheated before start-up, the valve rod and the valve core of the oil switching valve are rotated, so that high-temperature oil enters the bypass pipeline through the oil outlet connected with the bypass pipeline, and enters the three coke towers through the tower top pipeline connected with the bypass pipeline, and the three coke towers are preheated before start-up.

The invention provides an oil switching valve of a delayed coking device, which is characterized in that: the oil switching valve is a five-way ball valve and is provided with a valve body, a valve core, a valve cover, a valve rod, a filler gland and a rotary actuating mechanism, wherein the valve core is positioned in an inner cavity of the valve body, the valve rod is fixedly connected with the valve core, a valve core channel is arranged in the valve core, a valve core channel inlet is positioned at the bottom of the valve core, a valve core channel outlet is positioned on the outer side surface of the valve core, the rotary actuating mechanism is used for controlling the rotation of the valve rod and the valve core, the bottom and the side part of the valve body are respectively provided with one or four valve body openings, each valve body opening is provided with a sealing seat and a sealing sleeve, each sealing seat consists of a sealing seat flange and a sealing seat central cylinder, the sealing seat central cylinder is arranged in the sealing sleeve, a gap is reserved between the part of the sealing seat central cylinder, one end of the elastic element is close to the valve core, a sealing ring is arranged between the elastic element and the valve core, metal-to-metal elastic hard sealing is formed between the valve core and the sealing ring, meanwhile, the valve core is also spherical sealing, a central hole of a sealing seat at the bottom of the valve body is used as an oil inlet of the oil switching valve, and a central hole of a sealing seat at the side of the valve body is used as an oil outlet of the oil switching valve.

The invention has the following beneficial effects: (1) the invention uses only one oil switching valve, three cut-off valves and one bypass valve. The valves are special valves used at high temperature, and the price of each valve is hundreds of thousands to hundreds of thousands, so the equipment investment can be reduced by adopting the invention. Because the number of the valves is less, the complexity and difficulty of oil material switching operation can be reduced, and the process flow is simplified. (2) The number of the oil outlet pipelines and the bypass pipelines is less, and the workload of connection and arrangement is less. (3) And one oil inlet and four oil outlets of one oil switching valve are respectively connected with the oil inlet pipeline, the oil outlet pipeline and the bypass pipeline through flanges. The possibility of oil leakage is reduced due to the smaller number of flange connections (five total). In the invention, one oil inlet pipeline connected with the oil inlet can be respectively connected with one, two or more oil inlet pipelines from one, two or more heating furnaces. Since the above-mentioned line connection can be made by welding, there is no problem of leakage. (4) The invention provides a special oil switching valve for a delayed coking device, which is a five-way ball valve. The method can switch oil for three coke towers, and meets the requirement of the oil switching method of the delayed coking device. (5) The oil switching valve adopts a five-way ball valve, so that a full-path channel of the valve is easier to realize, the pressure drop of the oil switching valve is smaller, and the oil flows more smoothly. The valve core and the sealing ring are sealed by metal-to-metal elasticity, so that the switching torque of the oil switching valve is smaller, the action process is flexible and the problem of blocking cannot occur on the premise of ensuring the sealing effect. (6) The rotary actuating mechanism of the oil switching valve can be an electric, pneumatic or hydraulic actuating mechanism. By using the programmable controller, the automatic sequential operation of the rotary motion of the valve rod and the valve core can be realized, thereby realizing the automatic control of the oil material switching process.

The invention is mainly used for a delayed coking device which takes three coke drums as a group in an oil refinery, and oil is switched for the three coke drums (the oil comprises oil used for delayed coking reaction and oil used for preheating the coke drums before start-up). The invention can solve the problems of the existing oil switching method of the delayed coking device and the four-way oil switching valve, and reduce the operation and maintenance cost of the long-period operation of the delayed coking device.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The drawings and detailed description do not limit the scope of the invention as claimed.

Drawings

FIG. 1 is a schematic flow diagram of a prior art delayed coker with three coke drums as a battery.

FIG. 2 is a schematic flow diagram of a delayed coker of the present invention utilizing three coke drums.

Fig. 3 is a schematic view of an oil switching valve used in the present invention.

Fig. 4 is a sectional view taken along line a-a in fig. 3.

Fig. 5 is a sectional view taken along line B-B in fig. 4. The spool in fig. 5 is rotated to show the complete spool passage.

In fig. 1 to 5, the same reference numerals denote the same technical features.

Detailed Description

Referring to fig. 2, 3, 4 and 5, the delayed coking unit according to the present invention is composed of three coke drums 7, and the three coke drums 7 switch oil using an oil switching valve 2. The oil switching valve 2 is a five-way ball valve, and is provided with a valve body 11, a valve core 12, a valve cover 17, a valve rod 18, a packing 14, a packing gland 10 and a rotary actuator 25. The valve core 12 is positioned in the inner cavity of the valve body 11, and the valve rod 18 is fixedly connected with the valve core 12. The valve cover 17 is fixed to the upper portion of the valve body 11 by bolts, and the bracket 19 is fixed to the valve cover 17 by bolts. The valve stem 18 passes through the center of the bonnet 17, and the packing 14 is arranged in a packing box between the valve stem 18 and the bonnet 17 and is pressed by the packing gland 10. A90-degree turning valve core channel is arranged in the valve core 12, the inlet of the valve core channel is positioned at the bottom of the valve core 12, and the outlet of the valve core channel is positioned on the outer side surface of the valve core 12. The rotary actuator 25, which is used to control the rotation of the valve stem 18 and valve cartridge 12, may be an existing electric, pneumatic or hydraulic actuator (preferably an electric actuator), with a spare manual actuator.

The bottom and the side of the valve body 11 are respectively provided with one and four circular valve body openings, and each valve body opening is respectively provided with a sealing seat 20 and a sealing sleeve 21. The sealing sleeve 21 is cylindrical and is divided into two parts along the axial lead, and the outer side wall is tightly attached to the inner wall of the opening of the valve body. The sealing seat 20 consists of a sealing seat flange and a sealing seat central cylinder; the sealing seat flange is fixed on the outer side of the valve body 11, and the sealing seat central cylinder is arranged in the sealing sleeve 21. A gap is reserved between the part of the sealing seat central cylinder close to the sealing seat flange and the sealing sleeve 21, and a sealing cavity with a circular cross section is formed between the rest part of the sealing seat central cylinder and the sealing sleeve 21. The end part of the sealing sleeve 21 close to the sealing seat flange is provided with an annular boss protruding inwards and clamped in a groove on the part of the sealing seat central cylinder close to the sealing seat flange. An elastic element 22 is arranged in the sealed cavity, one end of the elastic element 22 is close to the valve core 12, a circular sealing ring 23 is arranged between the elastic element 22 and the valve core 12, and a part of the sealing ring 23 is positioned in the sealed cavity.

The sealing seat flange is provided with a central hole, and the central hole (the cross section is circular) of the sealing seat 20 is formed by the sealing seat flange and the inner cavity of the sealing seat central cylinder. The central hole of the sealing seat 20 at the bottom of the valve body 11 is used as the oil inlet 15 of the oil switching valve 2, and the central hole of the sealing seat 20 at the side of the valve body 11 is used as the oil outlet 16 of the oil switching valve 2. Therefore, the oil switching valve 2 of the present invention has one oil inlet 15 and four oil outlets 16, and one oil inlet 15 is located at the bottom of the valve body 11. The four oil outlets 16 are positioned at the side part of the valve body 11 and are uniformly distributed on a horizontal plane at equal angles, and the included angle between the axial leads of two adjacent oil outlets 16 is 90 degrees.

The elastic element 22 is generally a high temperature resistant (500-550 ℃) metal spring or a high temperature resistant metal corrugated pipe. The spring can be a cylindrical spring, a butterfly spring and other high-temperature resistant springs.

Sealing surfaces are provided on the outer surface of the spool 12 around both the spool passage inlet and the spool passage outlet. The valve core 12 presses on the sealing ring 23, and the elastic element 22 applies elastic force to the sealing ring 23, so that metal-to-metal elastic hard seal is formed between the valve core 12 and the sealing ring 23. The valve core 12 is generally spherical. In order to reduce the volume and weight of the valve core 12, machining may be performed, in which a portion of the valve core 12 is cut off at the upper and lower sides, the front and rear sides, and the left and right sides to form a plane, and only the sealing surfaces around the circular plane end surfaces of the inlet and outlet of the valve core passage are retained as spherical surfaces to contact the sealing surfaces on the sealing ring 23 to form a spherical surface seal. The valve core 12 and the sealing ring 23 are both made of high-temperature-resistant metal materials, sealing surfaces on the valve core 12 and the sealing ring 23 are both formed by high-temperature-resistant surface hardening technology (such as chromium plating, build-up welding high-temperature-resistant hard alloy and the like), and are provided with chromium plating layers or hard alloy layers and the like so as to realize the resistance to the abrasion of solid particles such as coke powder and the like at high temperature. The material of the valve body 11 and the valve cover 17 is generally high temperature resistant chromium-containing alloy steel or stainless steel. The material of the valve core 12 and the valve stem 18 is generally chromium-containing stainless steel.

Generally, the oil switching valve 2 is provided with a plurality of steam purging connecting pipes 13, the steam purging connecting pipes 13 are connected with steam purging channels, the steam purging channels are arranged on the valve body 11, the valve cover 17 and the sealing sleeve 21, and outlets of the steam purging channels are respectively positioned on the lower surface of the valve cover 17, the filler 14 and between the sealing seat central cylinder part close to the sealing seat flange and the sealing sleeve 21. A steam distribution groove 24 can be formed around the part of the central cylinder of the sealing seat, which is close to the flange of the sealing seat, and the outlet of the steam sweeping channel between the part of the central cylinder of the sealing seat, which is close to the flange of the sealing seat, and the sealing sleeve 21 is communicated with the steam distribution groove 24 so as to better distribute steam. In the operation process of the oil switching valve 2, steam enters the steam purging connecting pipe 13 and flows out from the outlet of each steam purging channel, enters the part of the inner cavity of the valve body 11 between the valve core 12 and the valve cover 17, the packing 14 and the steam distribution groove 24, and the purging steam entering the steam distribution groove 24 enters the sealing cavity through the gap (the gap is a sealing purging channel) between the part of the central cylinder of the sealing seat close to the flange of the sealing seat and the sealing sleeve 21 and then enters the sealing cavity to be purged at the positions. The steam purging can prevent oil containing coke powder from entering the area, coking, coke powder leakage and oil leakage are prevented, the elastic element 22 and the sealing ring 23 are protected from being corroded by the oil (especially the oil easy to coke), the elasticity of the elastic element 22 is guaranteed, and therefore long-period operation of the oil switching valve 2 is guaranteed.

When the oil switching valve 2 of the present invention is installed, the oil inlet 15 is connected to one oil inlet pipeline 1, and the oil inlet pipeline 1 is connected to one, two, or more (generally one, two, or three) oil inlet pipelines 1 from one, two, or more (generally one, two, or three) heating furnaces, respectively. In fig. 2, one oil inlet line 1 connected to the oil inlet 15 is connected to three oil inlet lines 1 from three heating furnaces. Each heating furnace heats an oil (single oil or mixed oil) and is connected (welded) to an oil inlet line 1 connected to an oil inlet 15 through an oil inlet line 1. An oil outlet 16 of the oil switching valve 2 is connected with a bypass pipeline 5, the bypass pipeline 5 is connected (welded) with an overhead pipeline 9 of the three coke drums 7, and a bypass valve 6 is arranged on the bypass pipeline 5. The other three oil outlets 16 of the oil switching valve 2, each oil outlet 16 is connected with a coke tower 7 through an oil outlet pipeline 3, and each oil outlet pipeline 3 is provided with a stop valve 4. A logic interlocking protection relationship exists between the oil switching valve 2 and the cut-off valve 4; the shut-off valve 4 on the oil outlet line 3 feeding oil to the coke drum 7 is opened and the shut-off valve 4 on the oil outlet line 3 not feeding oil to the coke drum 7 is closed. In fig. 2 (and fig. 1), the oil inlet line 1 is shown by a chain line, the oil outlet line 3 is shown by a thick solid line, and the bypass line 5 is shown by a broken line.

The process of switching oil from the oil switching valve 2 to the three coke drums 7 according to the present invention will be described with reference to fig. 2 to 5. Two or more kinds of oil (three kinds of oil in fig. 2) from two or more oil inlet lines 1 (three oil inlet lines 1 in fig. 2) of two or more heating furnaces (three heating furnaces in fig. 2, not shown) enter one oil inlet line 1 connected to an oil inlet 15 of an oil switching valve 2, are mixed in the oil inlet line 1, and then enter a spool passage of the oil switching valve 2 from the oil inlet 15. The delayed coker is operated continuously with three stages of oil transfer. In the first stage, valve stem 18 and valve spool 12 are rotated to allow oil to enter a coke drum 7 through an oil outlet 16 connected to oil outlet line 3 and oil outlet line 3, while the oil undergoes a delayed coking reaction. In the second stage, valve stem 18 and valve spool 12 are rotated to allow oil to enter second coke drum 7 through another oil outlet 16 connected to oil outlet line 3 and oil outlet line 3, while the oil undergoes delayed coking. In the third stage, the valve stem 18 and valve spool 12 are rotated to allow the oil to pass through the third oil outlet 16 connected to the oil outlet line 3 and the oil outlet line 3 into the third coke drum 7, where the oil undergoes a delayed coking reaction. The three stages are continuously and circularly carried out in sequence; the oil is switched into three coke drums 7 in sequence, the oil reacts in one coke drum 7, and the other coke drum 7 performs decoking operation. The oil gas generated by the delayed coking reaction enters a coking fractionating tower through an overhead pipeline 9, and the removed coke 8 is sent to a coke storage tank.

When the oil is one kind, a heating furnace is used for heating, and the heated oil enters the oil switching valve 2. The process of switching the oil is the same as that described in the previous paragraph, and the detailed description is omitted.

The oil heated by the heating furnace is high-temperature oil, the temperature is generally 500-550 ℃, and the oil is easy to coke. The oil is typically in the form of slurry oil, wax oil, vacuum residue, or other suitable heavy oil.

When the three coke drums 7 need to be preheated before start-up, the rotary actuator 25 rotates the valve rod 18 and the valve core 12 of the oil switching valve 2, so that high-temperature oil enters the bypass pipeline 5 through the oil outlet 16 connected with the bypass pipeline 5, and enters the three coke drums 7 through the tower top pipeline 9 connected with the bypass pipeline 5, and the three coke drums 7 are preheated before start-up.

When oil enters the oil switching valve 2 shown in fig. 3, 4 and 5, the inlet of the spool passage is always communicated with the oil inlet 15, and the outlet of the spool passage is always communicated with one oil outlet 16, so that a closed oil passage is formed. The rotary actuator 25 rotates the valve rod 18 and the valve core 12 of the oil switching valve 2 to communicate the valve core channel outlet from one oil outlet 16 to the other oil outlet 16, so that the oil switching valve 2 completes one stage of the oil switching operation (including oil switching for preheating the coke drum 7 before start-up).