A thickened oil grading sand removal and dechlorination integrated system and method

Abstract

The application discloses a thickened oil grading sand removal and chlorine removal integrated system and method, and relates to the field of oil production. The system comprises a large tank settling device, a sand collecting device, a cyclone sand remover and an oil-water separation device. The upper portion of the large tank settling device is provided with a crude oil passage outlet, and the lower portion is provided with a crude oil passage inlet. The sand gravel filter screen is arranged between the crude oil passage outlet and the crude oil passage inlet. The large tank settling device is connected with the cyclone sand remover. The cyclone sand remover is connected with the sand collecting device. The water inlets of the sand collecting device and the cyclone sand remover are respectively connected with the oil-water separation device. The sleeve pipe is arranged in the cyclone sand remover. The lower half of the inside of the sleeve pipe is used for placing the chlorine removal agent. The filter screen is arranged outside the chlorine removal agent. The sleeve pipe bottom is provided with a sleeve pipe outlet. The sleeve pipe outlet is connected with the oil-water mixture inlet of the oil-water separation device. The outside space of the sleeve pipe is sequentially divided into a flow guide cavity, a sand removal cavity and a sand discharge cavity from top to bottom. The crude oil is subjected to grading sand removal and simultaneously reduced in acidity and corrosiveness by using the large tank gravity settling, centrifugal action, chemical-water washing and other methods.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of crude oil transportation pretreatment, and particularly relates to a thickened oil grading sand removal and chlorine removal integrated system and method. BACKGROUND

[0002] The exploitation and use of thickened oil are continuously carried out over time, and new thickened oil energy is constantly added to storage. The annual refining capacity of China continues to grow rapidly at a rate of as high as 30%. Due to the very complex and variable underground geological conditions of thickened oil, there are still many unfavorable reasons for limiting the rational development and utilization of thickened oil wells. The first problem is layering sand production. Especially for steam flooding and steam stimulation used in thickened oil development, the formation is seriously eroded and damaged by high-pressure steam stimulation, which further leads to serious sand production in the formation. Sand production is the phenomenon that sand particles are transported out of the oil layer with fluid in the process of oil and gas exploitation.

[0003] Nowadays, the oil production is high, and the sand production problem is becoming more and more serious due to the bottleneck of sand prevention technology, and the sand prevention means has also reached a bottleneck, so the sand production problem is inevitable. Sand-containing crude oil in the transportation process can cause pipeline corrosion, blockage, and a series of problems such as damage to gathering equipment. The main reason for equipment corrosion is that the crude oil contains a certain amount of chloride ions, which can damage the internal anti-corrosion coating of the pipeline, and then the sand in the crude oil causes erosion and wear of the pipeline, resulting in damage to the equipment, leading to the need to frequently replace the crude oil transportation pipeline, valve, elbow, etc., causing a large amount of economic loss. Therefore, it is necessary to remove sand and chlorine from the produced crude oil, especially thickened oil. SUMMARY

[0004] In order to solve the problem in the prior art that the corrosion in crude oil transportation is mainly caused by chloride compounds corroding the internal surface protection layer of the pipeline or equipment, and then the sand carried in the crude oil erodes and corrodes the equipment and pipeline, resulting in serious damage to the internal surface of the pipeline and equipment, and even leakage; a thickened oil grading sand removal and chlorine removal integrated system is provided. The system first removes large-diameter sand in the crude oil through gravity tank settling, then separates small-diameter sand through a cyclone sand remover, and simultaneously reduces the concentration of chlorine-containing compounds with an alkaline earth metal chlorine removal agent, and sets a sand collecting device to recover the crude oil in the sand, and finally separates oil and water to obtain crude oil after sand and chlorine removal. Through the system, different sizes of sand in thickened oil can be more efficiently removed, and the thickened oil is treated for chlorine removal at the same time, which can obtain more efficient sand removal effect, and make the crude oil more convenient to transport.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an integrated system for heavy oil grading, sand removal, and dechlorination, comprising a large tank settling device, a sand collection device, a hydrocyclone sand separator, and an oil-water separator. The large tank settling device has an upper crude oil channel outlet and a lower crude oil channel inlet, with a gravel filter screen installed between the crude oil channel outlet and the crude oil channel inlet. The crude oil channel outlet of the large tank settling device is connected to the hydrocyclone sand separator, and the sand discharge outlet of the hydrocyclone sand separator is connected to the sand collection device. The outlet of the oil-water separator is connected to the inlet of both the sand collection device and the hydrocyclone sand separator. A sleeve is installed inside the hydrocyclone sand separator, with a dechlorinating agent placed in the lower half of the sleeve. A filter screen is installed outside the dechlorinating agent. A sleeve outlet is located at the bottom of the sleeve and is connected to the oil-water mixture inlet of the oil-water separator. The external space of the sleeve is divided from top to bottom into a guide chamber, a sand removal chamber, and a sand discharge chamber. A water inlet is opened on the top side of the guide chamber, and a spiral guide plate is installed inside the guide chamber. A baffle plate is connected to the bottom of the guide plate. The sand removal chamber is funnel-shaped.

[0006] Furthermore, the large tank settling device is equipped with a water level monitoring device, the sand discharge port is located at the bottom of the large tank settling device, and pumps are installed at both the crude oil channel inlet and crude oil channel outlet. The crude oil channel outlet is located at the top of the large tank settling device, and the crude oil channel inlet is located at the bottom of the large tank settling device.

[0007] Furthermore, the sand collection device is equipped with a water level monitoring device, a pressure sensor at the bottom of the sand collection device, a water inlet, a water outlet and a sand discharge port on the side wall of the sand collection device, a gravel inlet on the upper wall, the gravel inlet is connected to the sand discharge chamber, the water outlet is connected to the cyclone sand separator via a pump, and the water inlet is connected to the oil-water separator via a pump.

[0008] Furthermore, the sleeve is detachably installed in the cyclone separator.

[0009] Furthermore, the inner edge of the guide plate abuts against the sleeve, the outer edge of the guide plate connects to the inner wall of the guide cavity, the cross-section of the sand discharge cavity is larger than the cross-section of the upper sand removal cavity, the sand discharge cavity is provided with an inclined surface inside, and the sand discharge outlet is provided at the lowest point of the inclined surface.

[0010] Furthermore, the oil-water separation device has an oil-water mixture inlet, a water supply outlet, and a crude oil outlet. A water level monitoring device is installed in the oil-water separation device. The water supply outlet of the oil-water separation device is connected to a sand collection device and a hydrocyclone sand separator. The crude oil outlet is also provided on the oil-water separation device. The heights of the water inlet, the oil-water mixture inlet, the water level monitoring device, the crude oil outlet, and the water supply outlet decrease sequentially.

[0011] Furthermore, the water supply outlet of the oil-water separation device includes a No. 1 water supply channel and a No. 2 water supply channel respectively opened along the height. The No. 1 water supply channel is connected to the cyclone sand separator, and the No. 2 water supply channel is connected to the sand collection device.

[0012] The heavy oil classification, sand removal, and dechlorination method based on the above-described integrated heavy oil classification, sand removal, and dechlorination system includes the following steps:

[0013] When heavy oil enters the settling device of the large tank, most of the large-diameter sand and gravel are removed by settling. A small amount of large-diameter sand and gravel will be carried up by the crude oil. The filter screen prevents the large-diameter sand and gravel that rise with the liquid from entering the upper layer of the crude oil.

[0014] When the crude oil level is higher than the set level, the crude oil is transported to the hydrocyclone desander. The crude oil is mixed with water in the guide chamber to accelerate the flow rate. It enters the desander chamber for centrifugation. Sand and a small amount of heavy oil are on the outside and flow into the lower sand discharge chamber of the hydrocyclone desander. Under the action of gravity, it flows down the slope and is discharged from the sand discharge chamber outlet to the sand collection device.

[0015] Water and most of the oil shift inward and enter the casing through the filter screen. Chlorine-containing compounds in the oil-water mixture react with the dechlorinating agent, reducing the chloride ion concentration in the oil-water mixture before being discharged from the casing outlet to the oil-water separation device.

[0016] After a small amount of heavy oil and gravel enter the sand collection device, they gradually form layers, with the upper layer being oil and the lower layer being gravel.

[0017] The oil-water separator should be supplied with a set amount of water in advance. As the oil-water mixture from the cyclone separator enters the device, the oil and water gradually separate into layers under the action of gravity. After the oil and water have basically separated into layers, the upper layer of crude oil is discharged. When the liquid level in the oil-water separator is lower than the lower set value, water is added until the liquid level is higher than the higher set value, and then water addition is stopped.

[0018] Furthermore, a pressure sensor is installed at the bottom of the sand collection device. The side wall of the sand collection device is provided with a water inlet, a water outlet, and a sand discharge port. The water outlet is connected to a cyclone separator via a pump, and the water inlet is connected to an oil-water separator via a pump. The water level monitoring device inside the sand collection device includes a first upper water level monitoring device and a first lower water level monitoring device. If the liquid level is not higher than the lower water level monitoring device, the pressure at the bottom of the sand collection device reaches the set value, then the proportion of heavy oil is very small, and the sand is directly discharged from the sand discharge port.

[0019] When the oil level in the sand collection device is higher than the first lower water level monitoring device, water is introduced into the sand collection device. The water inlet is higher than the first lower water level monitoring device. Under the action of gravity and the density difference between oil and water, an oil-water mixture will be formed. After the level of the oil-water mixture is higher than the first upper water level monitoring device, the oil-water mixture mixes with the crude oil from the large tank settling device and enters the cyclone desander. When the level is lower than the first lower water level monitoring device, the pump at the water outlet is turned off and the sand discharge port is opened to discharge the sand and gravel.

[0020] Furthermore, the water outlet of the oil-water separation device is equipped with a No. 1 water supply channel and a No. 2 water supply channel. The height of the No. 1 water supply channel is higher than that of the No. 2 water supply channel. Water enters the cyclone desander and the sand collection device through the No. 1 water supply channel and the No. 2 water supply channel, respectively.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] The system described in this invention utilizes gravity for the settling process in large tanks to remove large-diameter sand and gravel from crude oil. A sand and gravel filter effectively prevents large-diameter sand and gravel from entering downstream equipment. Then, in a hydrocyclone desander, small-diameter sand and gravel are separated by centrifugal force. Simultaneously, a dechlorinating agent reduces the concentration of chlorine compounds, and a sand collection device recovers crude oil from the sand and gravel. Finally, oil-water separation yields desanded and dechlorinated crude oil, which sequentially passes through the large tank settling device and the hydrocyclone desander to remove both large and small-diameter sand and gravel. While ensuring excellent desanding performance, it effectively reduces the chloride ion concentration in the crude oil, better preventing corrosion and wear on subsequent crude oil processing and transportation equipment. All sand and gravel are discharged from the bottom of the desanding device by gravity. The system is simple, convenient, energy-efficient, and highly effective.

[0023] Furthermore, in the oil-water separation device, the upper layer of sand-free water enters the hydrocyclone desander, while the lower layer of water that may contain sand enters the sand collection device. This reduces the possibility of sand particles re-entering the hydrocyclone desander and discharges any sand particles that may be present to the sand collection device.

[0024] Furthermore, by setting up water level monitoring devices at different heights, oil in the sand and gravel can be recovered as much as possible, and sand particles that have already entered the sand collection device can be prevented from re-entering the hydrocyclone desander. Attached Figure Description

[0025] To more clearly illustrate the technical solution of the present invention, the accompanying drawings required for the description of the prior art are briefly introduced below.

[0026] Figure 1 This is an overall flowchart of the present invention;

[0027] Figure 2 This is a schematic diagram of the sand collection device.

[0028] Figure 3 This is a schematic cross-sectional view of a hydrocyclone sand separator.

[0029] Figure 4 This is a schematic diagram of an oil-water separation device.

[0030] Figure 5 This is a schematic diagram of the external structure of a cyclone sand separator;

[0031] Explanation of the labels in the diagram:

[0032] 1. First valve; 2. Large tank settling device; 3. First pump; 4. Sand collection device; 5. Second pump; 6. Cyclone sand separator; 7. Third pump; 8. Fourth pump; 9. Fifth pump; 10. Oil-water separator; 11. Sixth pump;

[0033] 401. First upper water level monitoring device; 402. First lower water level monitoring device; 403. Sand discharge outlet; 404. Gravel inlet; 405. Water supply inlet; 406. Water supply outlet; 407. Pressure sensor;

[0034] 601. Casing cover; 602. Casing; 603. Crude oil inlet; 604. Flow guide cavity; 605. Baffle; 606. Sand removal cavity; 607. Sand discharge cavity; 608. Water supply inlet; 609. Flow guide plate; 610. Dechlorinating agent; 611. Filter screen; 612. Casing outlet;

[0035] 1001. Oil-water mixture inlet; 1002. Water supply channel 1; 1003. Water supply channel 2; 1004. Water replenishment inlet;

[0036] 1005. Second upper water level monitoring device; 1006. Second lower water level monitoring device; 1007. Crude oil export; Detailed Implementation

[0037] To make the objectives and technical solutions of this invention more intuitive and clear, the technical solutions of this invention will be described more clearly and completely below in conjunction with the accompanying drawings.

[0038] like Figure 1 As shown, a heavy oil grading, sand removal, and dechlorination integrated system includes a large tank settling device 2, a sand collection device 4, a hydrocyclone sand separator 6, and an oil-water separator 10.

[0039] The large tank settling device 2 is connected to the sand collection device 4 and the cyclone sand removal device 6 via pipelines. The sand collection device 4 and the cyclone sand removal device 6 are in turn connected to the oil-water separation device 10 via pipelines. The cyclone sand removal device 6 is equipped with a sand discharge port, an crude oil channel inlet, a filter screen, and a crude oil channel outlet. The sand discharge port, crude oil channel inlet, filter screen, crude oil channel outlet, and water level monitoring device are arranged sequentially from bottom to top. A water level monitoring device is installed inside the large tank settling device 2. The sand discharge port is located at the bottom of the large tank settling device 2. The crude oil channel inlet and crude oil channel outlet are located on the wall of the large tank settling device 2. A pump 1 is installed at the crude oil channel inlet, and a second pump 5 is installed at the crude oil channel outlet. When the liquid level in the large tank settling device 2 reaches a set height, the second pump 5 is turned on to transport the crude oil to the cyclone sand removal device 6.

[0040] refer to Figure 3 and Figure 5The hydrocyclone sand separator 6 is divided into inner and outer parts. The inner part contains a detachable sleeve 602, with a sleeve cover 601 on top. The lower half of the inner part of the sleeve 602 contains a dechlorinating agent 610 suitable for alkaline earth metals, etc. A filter screen 611 is installed outside the dechlorinating agent 610, and a sleeve outlet 612 is located below the dechlorinating agent. The outer space of the sleeve 602 is divided from top to bottom into a flow guiding chamber 604, a sand removal chamber 606, and a sand discharge chamber 607. The flow guiding chamber 604 is equipped with a water inlet 608 and a crude oil inlet 607. 3. Guide plate 609 and baffle 605; Guide plate 609 is spiral-shaped. Water and crude oil enter the guide cavity 604, mix through guide plate 609, and then flow into the desanding cavity 606 through the gap between the outside of baffle 605 and the cavity wall of the cyclone desander 6 for desanding. Then, the oil-water mixture enters the sleeve 602 of the cyclone desander 6 through filter screen 611, is dechlorinated by dechlorinating agent 610, and flows out of the cyclone desander 6 through outlet 612 into the oil-water separation device 10; The lowest part of the cyclone desander 6 is the sand discharge cavity 607, and the interior of the sand discharge cavity 607 is provided with an inclined surface. Figure 3 As shown, a sand discharge outlet is provided at the lowest point of the slope. After the sand removal process by cyclone, the sand and gravel and a small amount of heavy oil are discharged from the sand discharge outlet of the sand discharge chamber 607 to the sand collection device 4 under the action of gravity.

[0041] As an optional embodiment, the sleeve 602 is threadedly connected to the top plate of the cyclone separator 6, or the sleeve 602 is directly inserted into the top plate of the cyclone separator 6, and a limiting ring is fixedly installed on the sleeve 602.

[0042] refer to Figure 2 The sand collection device 4 is equipped with a first upper water level monitoring device 401 and a first lower water level monitoring device 402. A pressure sensor 407 is installed at the bottom of the sand collection device 4. A water inlet 405, a water outlet 406, and a sand discharge port 403 are provided on the side wall of the sand collection device 4. A gravel inlet 404 is provided on the upper wall, which is connected to the sand discharge chamber 607 of the cyclone separator 6. The water inlet 405 is connected to the oil-water separator 10 via a third pump 7, and the water outlet 406 is connected to the cyclone separator 6 via a first pump 3. The sand and gravel discharged from the sand discharge outlet of the lower sand discharge chamber 607 of the sand separator 6 and a small amount of heavy oil enter the sand collection device 4 through the sand inlet 404. After the pressure sensor 407 detects that the gravity reaches the set value, the third pump 7 is turned on and water is introduced through the water inlet 405. The water and a small amount of heavy oil are mixed. After the first upper water level monitoring device 401 detects the water level, the first pump 3 is turned on and the oil-water mixture is discharged through the water outlet 406. When the water level drops to the first lower water level monitoring device 402, the first pump 3 and the third pump 7 are turned off and the sand discharge port 403 is opened to discharge the sand and gravel.

[0043] refer to Figure 4The oil-water separator 10 is equipped with an oil-water mixture inlet 1001, a first water supply channel 1002, a second water supply channel 1003, and a crude oil outlet 1007. A second upper water level monitoring device 1005 and a second lower water level monitoring device 1006 are installed on the inner wall. A water inlet 1004 is located at the top. The height of the oil-water mixture inlet 1001 is higher than the height of the second upper water level monitoring device 1005 and the second lower water level monitoring device 1006. The height of the second lower water level monitoring device 1006 is higher than the crude oil outlet 1007. The height of the crude oil outlet 1007 is... The water level is higher than that of the first water supply channel 1002 and the second water supply channel 1003. When the water level is lower than that of the second lower water level monitoring device 1006, water is replenished through the water inlet 1004 until the water level is higher than that of the second upper water level monitoring device 1005, at which point water replenishment stops. After the oil-water mixture enters the oil-water separation device 10, due to the difference in density between the oil and water, they will naturally separate into layers under the action of gravity. The upper layer of crude oil is discharged through the crude oil outlet 1007, and the lower layer of water enters the cyclone desander 6 and the sand collection device 4 through the first water supply channel 1002 and the second water supply channel 1003, respectively.

[0044] The specific implementation steps are as follows:

[0045] a. Open valve 1, and the crude oil to be processed enters the large tank settling device 2. As the water level of the crude oil gradually rises, most of the large-diameter sand and gravel in the crude oil will gradually move to the bottom of the container due to gravity. A small amount of large-diameter sand and gravel will be carried up by the crude oil. At this time, the filter screen inside the container blocks the large-diameter sand and gravel that rise with the liquid from entering the upper layer of the crude oil. When the crude oil level in the large tank settling device 2 is higher than the water level monitoring device, open the second pump 5 and the corresponding valve, and the crude oil flows into the cyclone desander 6. At the same time, open the fifth pump 9 and the corresponding valve to introduce water into the cyclone desander 6.

[0046] b. Crude oil enters the guide chamber 604 from the top of the hydrocyclone desander 6, and feed water enters the guide chamber 604 from the feed water inlet on the side wall of the hydrocyclone desander. The feed water flows fast, while the crude oil has high viscosity and flows slowly. The two gradually mix to form an oil-water mixture as they flow with the guide plate. The feed water carries the crude oil and flows quickly through the baffle into the desander chamber 606.

[0047] c. As the diameter of the sand removal chamber 606 gradually shrinks from top to bottom, the flow speed of the oil-water mixture gradually increases. At this time, due to the centrifugal force, the sand and gravel and a small amount of heavy oil on the outside flow into the lower sand discharge chamber of the cyclone sand remover 607. Under the action of gravity, they flow down the slope and are discharged from the sand discharge chamber outlet to the sand collection device 4. Water and most of the oil shift inward and enter the sleeve 602 inside the cyclone sand remover 6 through the filter screen 611. The chlorine-containing compounds in the oil-water mixture react with the dechlorinating agent such as alkaline earth metals in the sleeve 602, reducing the chloride ion concentration of the oil-water mixture, and are then discharged from the sleeve outlet 612 to the oil-water separation device 10.

[0048] d. After a small amount of heavy oil and gravel enter the sand collection device 4, they gradually form layers, with oil on the top and gravel on the bottom. If the pressure at the bottom of the sand collection device reaches the set value when the liquid level is not higher than the lower water level monitoring device, it indicates that the heavy oil content is very low. At this time, the gravel is directly discharged from the sand discharge port. Conversely, when the oil level is higher than the first lower water level monitoring device 402, the third pump 7 and the corresponding valve are opened to supply water into the sand collection device 4. Since the water inlet is higher than the first lower water level monitoring device 402, an oil-water mixture will be formed under the action of gravity and the density difference between oil and water. After the oil-water mixture level is higher than the first upper water level monitoring device 401, the third pump 7 and the corresponding valve are closed, and the first pump 3 and the corresponding valve are opened. The oil-water mixture mixes with the crude oil from the large tank settling device 2 and enters the cyclone desander 6. When the liquid level is lower than the lower water level monitoring device, the first pump 3 and the corresponding valve are closed, and the sand discharge port is opened to discharge the gravel.

[0049] e. A certain amount of water should be supplied to the oil-water separator 10 in advance, and the liquid level should be higher than the second lower water level monitoring device 1006. As the oil-water mixture from the cyclone desander enters the device, the oil and water gradually separate under the action of gravity. Different crude oil compositions will result in different separation times. After the oil and water have basically separated, the sixth pump 11 and the corresponding valve are opened to discharge the upper layer of crude oil. Since a very small amount of water will inevitably be discharged from the sand collection device during the whole process, when the liquid level in the oil-water separator is lower than the second lower water level monitoring device 1006, water is added through the water inlet 1004 until the liquid level is higher than the second upper water level monitoring device 1005. Water addition is stopped. After the oil-water mixture enters the oil-water separator 10, it will naturally separate under the action of gravity due to the different densities of oil and water. The upper layer of crude oil is discharged through the crude oil outlet 1007, and the lower layer of water enters the cyclone desander 6 and the sand collection device 4 through the first water supply channel 1002 and the second water supply channel 1003, respectively.

[0050] In summary:

[0051] 1. The present invention provides an integrated system for classifying, desanding, and dechlorinating heavy oil, which uses a large tank settling device and a hydrocyclone desander to remove sand from both large and small-diameter gravel, achieving a more effective and scientific desanding operation, further reducing the content of gravel in crude oil and the erosive effect of sand-containing crude oil on valves, pipelines, elbows, and other equipment.

[0052] 2. The integrated heavy oil grading, sand removal, and dechlorination system of the present invention effectively reduces the content of chlorine compounds in crude oil by using alkaline dechlorination agents such as alkaline earth metals while performing grading and sand removal, and provides significant protection for the anti-corrosion coating inside the pipeline transporting crude oil.

Claims

1. An integrated system for classifying, desanding, and dechlorinating heavy oil, characterized in that, include: The settling device (2) includes a large tank settling device (2), a sand collecting device (4), a hydrocyclone sand separator (6), and an oil-water separator (10). The large tank settling device (2) has an inlet for crude oil channels at its lower part and an outlet for crude oil channels at its upper part. A gravel filter screen is installed between the inlet and outlet of the crude oil channels. The outlet of the crude oil channels is connected to the inlet of the hydrocyclone sand separator (6). The outlet of the hydrocyclone sand separator (6) is connected to the sand collecting device (4). The oil-water separator (10) is equipped with an inlet for an oil-water mixture. (1001), water supply outlet, crude oil outlet (1007) and water replenishment inlet (1004), and equipped with a water level monitoring device; the cyclone sand separator (6) is equipped with a sleeve (602) inside, the lower half of the sleeve (602) is a place for dechlorinating agent (610), and a filter screen (611) is set outside the dechlorinating agent (610); the bottom of the sleeve (602) is equipped with a sleeve outlet (612), and the sleeve outlet (612) is connected to the oil-water mixture inlet (1001) of the oil-water separator (10). The casing (602) has a flow guide cavity (604), a sand removal cavity (606), and a sand discharge cavity (607) arranged sequentially from top to bottom in the external space of the casing (602). The top side of the flow guide cavity (604) is provided with a water inlet (608). A spiral guide plate (609) is installed inside the flow guide cavity (604), and a baffle (605) is installed at its bottom. The inner edge of the spiral guide plate (609) abuts against the casing (602), and its outer edge connects to the inner wall of the flow guide cavity. The sand removal cavity (606) is funnel-shaped. The sand discharge cavity (607)... The cross-section of 07) is larger than that of the sand removal chamber (606), and it has an inclined surface inside. The sand discharge outlet is located at the lowest point of the inclined surface. The water supply outlet of the oil-water separator (10) is connected to the water supply inlet (608) of the guide chamber (604) through the first water supply channel, and is connected to the sand collection device (4) through the second water supply channel. The water supply port (1004), the oil-water mixture inlet (1001), the water level monitoring device, the crude oil outlet (1007) and the water supply outlet decrease in height in sequence.

2. The integrated heavy oil grading, desanding, and dechlorination system according to claim 1, characterized in that, The large tank settling device (2) is equipped with a water level monitoring device. The sand discharge port is located at the bottom of the large tank settling device (2). Pumps are installed at both the crude oil channel inlet and the crude oil channel outlet. The crude oil channel outlet is located at the top of the large tank settling device (2), and the crude oil channel inlet is located at the bottom of the large tank settling device (2).

3. The integrated heavy oil grading, desanding, and dechlorination system according to claim 1, characterized in that, The sand collection device (4) is equipped with a water level monitoring device inside. The sand collection device (4) is equipped with a pressure sensor (407) at the bottom. The sand collection device (4) is equipped with a water inlet (405), a water outlet (406) and a sand discharge port (403) on the side wall. The sand and gravel inlet (404) is equipped on the upper wall. The sand and gravel inlet (404) is connected to the sand discharge chamber (607). The water outlet (406) is connected to the cyclone separator (6) via a pump. The water inlet (405) is connected to the oil-water separator (10) via a pump.

4. The integrated heavy oil grading, desanding, and dechlorination system according to claim 1, characterized in that, The sleeve (602) is detachably installed in the cyclone separator (6).

5. The integrated heavy oil grading, desanding, and dechlorination system according to claim 1, characterized in that, The water outlet of the oil-water separation device (10) includes a first water supply channel (1002) and a second water supply channel (1003) opened along the height respectively. The first water supply channel (1002) is connected to the cyclone sand separator (6), and the second water supply channel (1003) is connected to the sand collection device (4).

6. A method for heavy oil classification, sand removal, and dechlorination based on the integrated heavy oil classification, sand removal, and dechlorination system according to any one of claims 1-5, characterized in that, Includes the following steps: Heavy oil enters the large tank settling device (2) to first settle and remove most of the large-diameter gravel. A small amount of large-diameter gravel will be carried up by the crude oil. The filter screen blocks the large-diameter gravel that rises with the liquid from entering the upper layer of the crude oil. When the crude oil level is higher than the set level, the crude oil is transported to the hydrocyclone desander (6). The crude oil is mixed with water through the guide chamber (604) to accelerate the flow rate and enter the desander chamber (606) for centrifugation. The sand and gravel and a small amount of heavy oil are on the outside and flow into the lower sand discharge chamber (607) of the hydrocyclone desander. Under the action of gravity, it flows down the slope and is discharged from the sand discharge chamber outlet to the sand collection device (4). Water and most of the oil are shifted inward and enter the casing (602) through the filter screen (611). The chlorine-containing compounds in the oil-water mixture react with the dechlorinating agent to reduce the chloride ion concentration of the oil-water mixture and then discharge it from the casing outlet (612) to the oil-water separator (10). After a small amount of heavy oil and gravel enter the sand collection device (4), they gradually form layers, with the upper layer being oil and the lower layer being gravel; The oil-water separator (10) should be supplied with a set amount of water in advance. As the oil-water mixture from the cyclone separator (6) enters the device, the oil and water gradually separate into layers under the action of gravity. After the oil and water are basically separated, the upper layer of crude oil is discharged. When the liquid level in the oil-water separator is lower than the smaller set value, water is added until the liquid level is higher than the larger set value, and then water is added.

7. The method for classifying, desanding, and dechlorinating heavy oil according to claim 6, characterized in that, The sand collection device (4) is equipped with a pressure sensor (407) at the bottom. The sand collection device (4) is equipped with a water inlet (405), a water outlet (406) and a sand discharge port (403) on its side wall. The water outlet (406) is connected to the cyclone separator (6) via a pump. The water inlet (405) is connected to the oil-water separator (10) via a pump. The internal water level monitoring device of the sand collection device (4) includes a first upper water level monitoring device (401) and a first lower water level monitoring device (402). If the liquid level is not higher than the lower water level monitoring device, the pressure at the bottom of the sand collection device reaches the set value. Then the heavy oil content is very low, and the sand is directly discharged from the sand discharge port. When the oil level in the sand collection device (4) is higher than the first lower water level monitoring device (402), water is introduced into the sand collection device (4). The water inlet (405) is higher than the first lower water level monitoring device (402). Under the action of gravity and the density difference between oil and water, an oil-water mixture will be formed. After the oil-water mixture level is higher than the first upper water level monitoring device (401), the oil-water mixture mixes with the crude oil from the large tank settling device (2) and enters the cyclone desander (6). When the level is lower than the first lower water level monitoring device (402), the pump of the water outlet (406) is turned off and the sand discharge port is opened to discharge the sand and gravel.

8. The method for classifying, desanding, and dechlorinating heavy oil according to claim 6, characterized in that, The water outlet of the oil-water separation device (10) is provided with a No. 1 water supply channel (1002) and a No. 2 water supply channel (1003). The height of the No. 1 water supply channel (1002) is higher than that of the No. 2 water supply channel (1003). Water enters the cyclone desander (6) and the sand collection device (4) through the No. 1 water supply channel (1002) and the No. 2 water supply channel (1003) respectively.

Images