Catalytic cracking slurry oil filtering system and filtering method thereof

Abstract

The invention discloses a catalytic cracking oil slurry filtering system and a filtering method thereof, and belongs to the technical field of oil slurry filtering, the catalytic cracking oil slurry filtering system comprises an upper annular pipe, the tail end of the upper annular pipe is communicated with a circulating pump, a liquid outlet of the circulating pump is communicated with the starting end of the upper annular pipe, the upper annular pipe is connected with a plurality of filters in series, and the filters are communicated with the circulating pump. A liquid inlet pipe is communicated with the initial end of the upper annular pipe, a liquid inlet pump is arranged on the liquid inlet pipe, the bottoms of the filters are jointly communicated with a lower annular pipe, two connecting branch pipes are communicated with the tail end of the lower annular pipe, first control valves are arranged on the two connecting branch pipes, settling ponds are communicated with the tail ends of the two connecting branch pipes respectively, and a second control valve is arranged on the settling ponds. The lower side walls of the two sedimentation tanks are communicated with a backflow pipe, the middle of the backflow pipe is provided with a two-way liquid pump, and the top of the backflow pipe is communicated with the upper annular pipe, the number of the filters is not limited, the filters can be additionally arranged according to actual production requirements, and the filtering efficiency of oil slurry is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil slurry filtration, and in particular to a catalytic cracking oil slurry filtration system and a filtration method thereof. Background Art

[0002] Catalytic cracking slurry is a substance produced during the catalytic cracking process. The catalytic cracking process generally consists of three parts, namely the reaction-regeneration system, the fractionation system, and the absorption-stabilization system. In the fractionation system, the reaction products from the reactor enter the fractionation tower from the bottom, and after passing through the desuperheating section at the bottom, they are divided into several intermediate products in the fractionation section, among which the bottom product is the slurry.

[0003] The liquid substances in catalytic cracking oil slurry are mainly various hydrocarbon compounds, including saturated hydrocarbons, aromatic hydrocarbons and polycyclic aromatic hydrocarbons. These compounds are the main components of oil slurry and account for most of the total amount of oil slurry. Among them, aromatic hydrocarbons and polycyclic aromatic hydrocarbons are high-quality raw materials for producing high value-added products such as needle coke, activated carbon fiber, road asphalt, plasticizers, etc.

[0004] The solid matter in catalytic cracking oil slurry is mainly catalyst powder, coke powder and other solid impurities. The presence of these solid substances seriously affects the subsequent processing and utilization of the oil slurry, so it is necessary to remove the solids. The solid particles in the oil slurry are mainly composed of catalyst fine powder, coke powder, alkali metals, inorganic salts and metal elements.

[0005] In order to remove solid particles from oil slurry, commonly used methods include sedimentation separation, filtration separation, centrifugal separation and electrostatic separation, etc. Among them, the filtration method has a stable separation effect and is widely used in industrial production. The main problem of the existing catalytic cracking oil slurry filtration system is its low filtration efficiency. Even if two filters are used to work alternately to achieve the purpose of continuous filtration, its filtration efficiency is still limited by the filtration efficiency of a single filter. Therefore, an efficient filtration system is needed to improve the filtration efficiency of catalytic cracking oil slurry. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a catalytic cracking oil slurry filtering system and a filtering method thereof.

[0007] The technical scheme of the present invention is: a catalytic cracking oil slurry filtering system, comprising an upper annular tube, the end of the upper annular tube is connected with a circulation pump, the liquid outlet of the circulation pump is connected with the starting end of the upper annular tube, a plurality of filters are connected in series on the upper annular tube, the starting end of the upper annular tube is connected with a liquid inlet pipe, the liquid inlet pipe is provided with a liquid inlet pump, the bottom of the filter is commonly connected with a lower annular tube, the end of the lower annular tube is connected with two connecting branches, the two connecting branches are each provided with a control valve 1, the ends of the two connecting branches are respectively connected with a sedimentation tank, the lower side walls of the two sedimentation tanks are connected with a return pipe, a bidirectional liquid pump is provided in the middle of the return pipe, the top of the return pipe is connected with the upper annular tube, and a control valve 2 is provided at the connection point, the upper parts of the plurality of filters are connected with liquid outlet branches, the ends of the plurality of liquid outlet branches are commonly connected with a liquid outlet pipe, and a control valve 3 is provided at the connection point between the liquid outlet branch and the liquid outlet pipe, the right side of the liquid outlet pipe is connected with a liquid outlet pump, and the liquid outlet of the liquid outlet pump is connected with a drain pipe.

[0008] Furthermore, the filter comprises a cross tube, both left and right ends of the cross tube are connected to the upper annular tube, the lower end of the cross tube is connected to the lower annular tube, and the top of the cross tube is threadedly connected with a filter element mechanism.

[0009] Description: The oil slurry flows from the upper annular tube into the lower annular tube, and the solid particles accumulate in the lower annular tube under the action of gravity. The structure in which the filter element mechanism is threadedly connected to the cross tube facilitates the replacement of the filter element mechanism.

[0010] Furthermore, the filter element mechanism comprises a filter element head, a cavity is formed inside the filter element head, the upper part of the cavity is connected with the liquid outlet branch pipe, and the lower part of the cavity is connected with a filter element.

[0011] Note: The oil slurry filtered by the filter element flows into the outlet pipe from the outlet branch pipe.

[0012] Furthermore, the top of the cavity is connected with an air inlet pipe, the end of the air inlet pipe is connected with a nitrogen bin, and a control valve four is provided at the connection point, and the air inlet of the nitrogen bin is connected with a nitrogen compressor.

[0013] Description: High-pressure nitrogen is filled into the cavity through the air inlet pipe to backwash the filter element, causing the solid particles attached to the filter element to fall off and improve the filtration efficiency of the filter element.

[0014] Furthermore, the sedimentation tank includes a tank body, a percolation plate is fixedly connected to the middle of the tank body, a filtration bin is formed above the percolation plate, a filtrate bin is formed below the percolation plate, a top plate is fixedly connected to the top of the sedimentation tank, a liquid pump and a two-way air pump are connected above the top plate, a liquid inlet of the liquid pump is connected to the connecting branch pipe, and the two-way air pump is connected to the nitrogen bin through a connecting air pipe.

[0015] Description: The oil slurry in the lower annular tube enters the filter chamber from the liquid pump, and is filtered by the filter plate, where solid particles are blocked. The oil slurry filtered by the filter plate is then discharged from the filtrate chamber through the two-way liquid pump into the upper annular tube for circulation. When the filter plate is clogged, resulting in a decrease in the filtration effect, the two-way liquid pump is used for backwashing to restore the filtration effect of the filter plate.

[0016] Furthermore, a filter residue discharge port is provided on one side of the filter bin, and a closed door is hinged on the outer side of the filter residue discharge port.

[0017] Note: Clean the solid particles accumulated in the filter bin through the filter residue discharge port.

[0018] Furthermore, an agitator is installed on the top plate, and the agitator includes a stirring rod, and the stirring rod is rotatably connected in the filter bin, and a stirring motor is connected to the top plate to drive the stirring rod to rotate.

[0019] Note: The agitator is used to suspend solid particles, reduce the probability of clogging of the filter plate, and extend the working time of the filter plate.

[0020] Furthermore, a flocculator is installed on the top plate, and the flocculator includes a medicine bin, the bottom of which is fixedly connected to the upper surface of the top plate by a connecting rod, a medicine adding port is provided on one side of the medicine bin, a feeding pipe is connected to the bottom of the medicine bin, a spiral feeding rod is rotatably connected to the feeding pipe, a feeding motor for driving the spiral feeding rod to rotate is connected to the top of the medicine bin, a spray pipe is connected to the lower end of the feeding pipe, one end of the spray pipe is connected to the nitrogen bin by an air supply pipe, and a control valve six is ​​provided at the connection point, and the other end of the spray pipe passes through the top plate to the top of the filter bin.

[0021] Description: Spray the flocculant onto the oil slurry through a flocculator, and then stir it evenly with a stirrer to quickly flocculate the solid particles in the oil slurry and reduce the content of solid particles in the oil slurry.

[0022] Furthermore, a guide valve is provided at the connection between the left and right ends of the cross pipe and the upper annular pipe, a bypass pipe is connected between the two guide valves, a control valve seven is provided on the bypass pipe, and a control valve eight is provided at the connection between the lower end of the cross pipe and the lower annular pipe.

[0023] Note: When the filter element needs to be replaced, the oil slurry is diverted to the bypass pipe through the guide valve, and the control valve eight is closed at the same time, so that the oil slurry does not pass through the filter, and then the filter element is replaced. This structure does not affect the normal operation of other filters when replacing the filter element.

[0024] Furthermore, a filtering method of a catalytic cracking oil slurry filtering system is provided, based on the above-mentioned catalytic cracking oil slurry filtering system, comprising the following steps:

[0025] S1. The oil slurry enters the upper annular tube from the liquid inlet pipe, and flows into the lower annular tube when the oil slurry flows through the filter. The flow rate of the oil slurry in the upper annular tube is greater than that in the lower annular tube. After the flowing oil slurry is filtered by the filter, solid particles accumulate in the lower annular tube. The lower annular tube discharges the oil slurry with a large content of solid particles into the sedimentation tank through the control valve on the connecting branch pipe.

[0026] S2. The oil slurry with large solid particle content is precipitated in the sedimentation tank to remove large solid particles, and the oil slurry with small solid particle content is refluxed to the upper annular pipe through the reflux pipe for circulation;

[0027] S3. The oil slurry filtered by the filter is discharged into the liquid outlet pipe through the liquid outlet branch pipe, and then discharged into the liquid outlet pipe through the liquid outlet pump.

[0028] The beneficial effects of the present invention are:

[0029] (1) The flow rate of the upper annular tube of the present invention is fast, and the flow rate of the lower annular tube is slow. The unfiltered oil slurry circulates in the upper annular tube, and the oil slurry lost in the upper annular tube is replenished through the liquid inlet pipe. The oil slurry in the upper annular tube flows into the lower annular tube through the filter. Solid particles accumulate in the lower annular tube and are then filtered through two sedimentation tanks to remove large solid particles. The oil slurry is then filtered by the filter. The number of filters of the present invention is not limited. Filters can be added according to actual production needs, thereby improving the filtering efficiency of the oil slurry.

[0030] (2) The present invention uses the gravity of the solid particles in the oil slurry to make the solid particles in the oil slurry settle to the lower annular tube in the filter. This method of solid-liquid separation has low energy consumption and high efficiency. The unfiltered oil slurry of the present invention is circulated in the upper annular tube. During the circulation process, the solid particles in the oil slurry will also settle into the lower annular tube. The oil slurry in the lower annular tube has a high content of solid particles. Through the combination of filtration and flocculant, the solid particles in the oil slurry can be filtered out more efficiently and quickly.

[0031] (3) The filter element mechanism in the filter of the present invention is easy to replace, and the replacement of the filter element in a single filter does not affect the normal operation of other filters. In addition, the filter element mechanism of the present application can be backflushed with nitrogen to clean the attachments on the surface of the filter element, thereby improving the filtration efficiency of the filter element and extending the effective working time of the filter element. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a top view of the structure of the present invention.

[0033] Figure 2 It is a top view of the connection relationship between the lower annular pipe and the sedimentation tank of the present invention.

[0034] Figure 3 It is a front view structural diagram of the filter of the present invention.

[0035] Figure 4 It is a main structural diagram of the sedimentation tank of the present invention.

[0036] Figure 5 yes Figure 1 Enlarged view of point A in the middle.

[0037] Among them, 1-upper annular pipe, 11-circulation pump, 2-filter, 3-liquid inlet pipe, 31-liquid inlet pump, 4-lower annular pipe, 41-connecting branch pipe, 42-control valve one, 5-sedimentation tank, 6-reflux pipe, 61-bidirectional liquid pump, 71-liquid outlet branch pipe, 7-liquid outlet pipe, 72-control valve three, 73-liquid outlet pump, 74-drain pipe, 21-cross pipe, 22-filter element mechanism, 221-filter element head, 222-cavity, 223-filter element, 224-inlet pipe, 225-nitrogen warehouse, 226-control valve four, 227-nitrogen compressor, 51-tank body, 52-filtration Plate, 53-filter bin, 54-filtrate bin, 55-top plate, 56-liquid pump, 57-bidirectional air pump, 571-connecting air pipe, 531-filter residue discharge port, 532-sealed door, 58-agitator, 581-stirring rod, 582-stirring motor, 59-flocculator, 591-drug bin, 592-connecting rod, 593-dosing port, 594-feeding pipe, 595-spiral feeding rod, 596-feeding motor, 597-spraying pipe, 598-air supply pipe, 599-control valve six, 23-guide valve, 24-bypass pipe, 241-control valve seven, 25-control valve eight. DETAILED DESCRIPTION

[0038] Embodiment 1:

[0039] like Figure 1 , Figure 2As shown, a catalytic cracking oil slurry filtering system comprises an upper annular pipe 1, the end of the upper annular pipe 1 is connected to a circulation pump 11, the liquid outlet of the circulation pump 11 is connected to the beginning of the upper annular pipe 1, a plurality of filters 2 are connected in series on the upper annular pipe 1, the beginning of the upper annular pipe 1 is connected to a liquid inlet pipe 3, the liquid inlet pipe 3 is provided with a liquid inlet pump 31, the bottom of the filters 2 are connected to a lower annular pipe 4, the ends of the lower annular pipe 4 are connected to two connecting branches 41, the two connecting branches 41 are provided with a control valve 1 42, and the two connecting branches 41 are connected to the upper annular pipe 1. The ends are respectively connected to sedimentation tanks 5, the lower side walls of the two sedimentation tanks 5 are connected to a reflux pipe 6, a two-way liquid pump 61 is provided in the middle of the reflux pipe 6, the top of the reflux pipe 6 is connected to the upper annular pipe 1, and a control valve 2 62 is provided at the connecting point, a plurality of filters 2 are connected to liquid outlet branches 71 above, the ends of the plurality of liquid outlet branches 71 are commonly connected to a liquid outlet pipe 7, and a control valve 3 72 is provided at the connecting point between the liquid outlet branch pipe 71 and the liquid outlet pipe 7, the right side of the liquid outlet pipe 7 is connected to a liquid outlet pump 73, and the liquid outlet of the liquid outlet pump 73 is connected to a discharge pipe 74.

[0040] like Figure 3 As shown, the filter 2 includes a cross tube 21, both left and right ends of the cross tube 21 are connected to the upper annular tube 1, the lower end of the cross tube 21 is connected to the lower annular tube 4, and the top of the cross tube 21 is threadedly connected with a filter element mechanism 22.

[0041] The oil slurry flows from the upper annular tube 1 into the lower annular tube 4 , and solid particles accumulate in the lower annular tube 4 under the action of gravity. The structure in which the filter element mechanism 22 is threadedly connected to the cross tube 21 facilitates the replacement of the filter element mechanism 22 .

[0042] The filter element mechanism 22 includes a filter element head 221 , and a cavity 222 is formed inside the filter element head 221 . The upper part of the cavity 222 is connected to the liquid outlet branch pipe 71 , and the lower part of the cavity 222 is connected to the filter element 223 .

[0043] The oil slurry filtered by the filter element 223 flows into the liquid outlet pipe 7 from the liquid outlet branch pipe 71.

[0044] The top of the cavity 222 is connected to an air inlet pipe 224, the end of the air inlet pipe 224 is connected to a nitrogen bin 225, and a control valve 226 is provided at the connection point, and the air inlet of the nitrogen bin 225 is connected to a nitrogen compressor 227.

[0045] High-pressure nitrogen is filled into the cavity 222 through the air inlet pipe 224 to backwash the filter element 223 , thereby removing solid particles attached to the filter element 223 and improving the filtering efficiency of the filter element 223 .

[0046] like Figure 4As shown, the sedimentation tank 5 includes a tank body 51, a percolation plate 52 is fixedly connected to the middle of the tank body 51, a filter chamber 53 is formed above the percolation plate 52, and a filtrate chamber 54 is formed below the percolation plate 52. A top plate 55 is fixedly connected to the top of the sedimentation tank 5, and a liquid pump 56 and a two-way air pump 57 are connected above the top plate 55. The liquid inlet of the liquid pump 56 is connected to the connecting branch pipe 41, and the two-way air pump 57 is connected to the nitrogen chamber 225 through the connecting air pipe 571.

[0047] The oil slurry in the lower annular tube 4 enters the filter chamber 53 from the liquid pump 56, and is filtered by the filter plate 52, where solid particles are blocked. The oil slurry filtered by the filter plate 52 is then discharged from the filtrate chamber 54 through the two-way liquid pump 61 into the upper annular tube 1 for circulation. When the filter plate 52 is clogged and the filtration effect is reduced, the two-way liquid pump 61 is used for backwashing to restore the filtration effect of the filter plate 52.

[0048] Embodiment 2:

[0049] The difference between this embodiment and the first embodiment is that a filter residue discharge port 531 is provided on one side of the filter bin 53 in this embodiment, and a sealed door 532 is hinged on the outer side of the filter residue discharge port 531 .

[0050] Compared with Embodiment 1, this embodiment cleans the solid particles accumulated in the filter bin 53 through the filter residue discharge port 531 .

[0051] Embodiment 3:

[0052] The difference between this embodiment and embodiment 2 is that in this embodiment, an agitator 58 is installed on the top plate 55, and the agitator 58 includes a stirring rod 581, which is rotatably connected in the filter chamber 53, and a stirring motor 582 is connected to the top plate 55 to drive the stirring rod 581 to rotate.

[0053] Compared with Example 2, this embodiment uses the agitator 58 to suspend solid particles, thereby reducing the probability of clogging of the infiltration plate 52 and extending the working time of the infiltration plate 52.

[0054] Embodiment 4:

[0055] The difference between this embodiment and embodiment 3 is that, in this embodiment, a flocculator 59 is installed on the top plate 55, and the flocculator 59 includes a medicine bin 591. The bottom of the medicine bin 591 is fixedly connected to the upper surface of the top plate 55 through a connecting rod 592, and a drug adding port 593 is provided on one side of the medicine bin 591. A feeding pipe 594 is connected to the bottom of the medicine bin 591, and a spiral feeding rod 595 is rotatably connected in the feeding pipe 594. A feeding motor 596 for driving the spiral feeding rod 595 to rotate is connected to the top of the medicine bin 591, and a spray pipe 597 is connected to the lower end of the feeding pipe 594. One end of the spray pipe 597 is connected to the nitrogen bin 225 through an air supply pipe 598, and a control valve 6 599 is provided at the connection point. The other end of the spray pipe 597 passes through the top plate 55 to the top of the filter bin 53.

[0056] Compared with Example 3, in this embodiment, the flocculant is sprayed on the oil slurry through the flocculator 59 and then stirred evenly through the agitator 58, so that the solid particles in the oil slurry are quickly flocculated, thereby reducing the content of the solid particles in the oil slurry.

[0057] Embodiment 5:

[0058] The difference between this embodiment and embodiment 4 is that in this embodiment, Figure 5 As shown, a guide valve 23 is provided at the connection between the left and right ends of the cross pipe 21 and the upper annular pipe 1, a bypass pipe 24 is connected between the two guide valves 23, and a control valve seven 241 is provided on the bypass pipe 24, and a control valve eight 25 is provided at the connection between the lower end of the cross pipe 21 and the lower annular pipe 4.

[0059] When the filter element mechanism 22 needs to be replaced, the oil slurry is directed to the bypass pipe 24 through the guide valve 23, and the control valve 8 25 is closed at the same time to prevent the oil slurry from passing through the filter 2. The filter element mechanism 22 is then replaced. This structure replaces the filter element mechanism 22 without affecting the normal operation of other filters 2.

[0060] Embodiment 6:

[0061] This embodiment provides a filtering method for a catalytic cracking oil slurry filtering system, based on a catalytic cracking oil slurry filtering system in the above embodiment 5, comprising the following steps:

[0062] S1, the oil slurry enters the upper annular tube 1 from the liquid inlet pipe 3, and flows into the lower annular tube 4 when the oil slurry flows through the filter 2. The flow rate of the oil slurry in the upper annular tube 1 is greater than that in the lower annular tube 4. After the flowing oil slurry is filtered by the filter 2, solid particles accumulate in the lower annular tube 4. The lower annular tube 4 discharges the oil slurry with a large content of solid particles into the sedimentation tank 5 through the control valve 42 on the connecting branch pipe 41;

[0063] S2, the oil slurry with large solid particle content is precipitated in the sedimentation tank 5 to remove large solid particles, and the oil slurry with small solid particle content is refluxed to the upper annular pipe 1 through the reflux pipe 6 for circulation;

[0064] S3, the oil slurry filtered by the filter 2 is discharged into the liquid outlet pipe 7 through the liquid outlet branch pipe 71, and then passes through the liquid outlet pump 73 to the liquid outlet pipe 74;

[0065] S4, divert the oil slurry to the bypass pipe 24 through the diversion valve 23, open the control valve 7 241 and close the control valve 8 25 at the same time, then replace the filter element 22, fill nitrogen into the cavity 222 through the air inlet pipe 224, backwash the filter element 223, and make the solid particles attached to the surface of the filter element 223 fall off;

[0066] S5, pressurizing the filter chamber 53 by the bidirectional air pump 57 to improve the filtration efficiency, and making the oil slurry in the filtrate chamber 54 flow to the filter chamber 53 by the reverse operation of the bidirectional air pump 57 and the bidirectional liquid pump 61, so as to flush the blockage on the filtration plate 52 and improve the filtration efficiency of the filtration plate 52;

[0067] S6. The agitator 58 and the flocculator 59 cooperate to rapidly flocculate and precipitate the solid particles in the oil slurry, thereby improving the filtration efficiency and purification effect of the oil slurry.

[0068] The circulation pump 11, liquid inlet pump 31, control valve one 42, bidirectional liquid pump 61, control valve three 72, liquid outlet pump 73, filter element 223, control valve four 226, nitrogen compressor 227, percolation plate 52, liquid pump 56, bidirectional air pump 57, stirring motor 582, feeding motor 596, control valve six 599, guide valve 23, control valve seven 241, and control valve eight 25 used in the above embodiments are all commercially available products. As long as the functions of the present invention can be achieved, those skilled in the art can choose to use them according to common sense, and no special limitation is made here.

Claims

1. A catalytic cracking oil slurry filtration system, characterized in that: The invention comprises an upper annular tube (1), the end of the upper annular tube (1) is connected to a circulation pump (11), the liquid outlet of the circulation pump (11) is connected to the beginning of the upper annular tube (1), a plurality of filters (2) are connected in series on the upper annular tube (1), the beginning of the upper annular tube (1) is connected to a liquid inlet pipe (3), the liquid inlet pipe (3) is provided with a liquid inlet pump (31), the bottom of the filter (2) is connected to a lower annular tube (4), the end of the lower annular tube (4) is connected to two connecting branches (41), the two connecting branches (41) are each provided with a control valve 1 (42), the ends of the two connecting branches (41) are respectively connected to A sedimentation tank (5), wherein the lower side walls of the two sedimentation tanks (5) are connected with a return pipe (6), a bidirectional liquid pump (61) is provided in the middle of the return pipe (6), the top of the return pipe (6) is connected with the upper annular pipe (1), and a control valve 2 (62) is provided at the connection point, a plurality of filters (2) are connected with a liquid outlet branch pipe (71) at the top, the ends of the plurality of liquid outlet branch pipes (71) are commonly connected with a liquid outlet pipe (7), and a control valve 3 (72) is provided at the connection point between the liquid outlet branch pipe (71) and the liquid outlet pipe (7), the right side of the liquid outlet pipe (7) is connected with a liquid outlet pump (73), and the liquid outlet of the liquid outlet pump (73) is connected with a discharge pipe (74).

2. A catalytic cracking oil slurry filtration system according to claim 1, characterized in that: The filter (2) comprises a cross tube (21), the left and right ends of the cross tube (21) are both connected to the upper annular tube (1), the lower end of the cross tube (21) is connected to the lower annular tube (4), and the top of the cross tube (21) is threadedly connected to a filter element mechanism (22).

3. A catalytic cracking oil slurry filtration system as claimed in claim 2, characterized in that: The filter element mechanism (22) comprises a filter element head (221), a cavity (222) is formed inside the filter element head (221), the upper part of the cavity (222) is connected to the liquid outlet branch pipe (71), and the lower part of the cavity (222) is connected to a filter element (223).

4. A catalytic cracking oil slurry filtration system as claimed in claim 3, characterized in that: The top of the cavity (222) is connected to an air inlet pipe (224), the end of the air inlet pipe (224) is connected to a nitrogen bin (225), and a control valve (226) is provided at the connection point, and the air inlet of the nitrogen bin (225) is connected to a nitrogen compressor (227).

5. A catalytic cracking oil slurry filtration system as claimed in claim 4, characterized in that: The sedimentation tank (5) comprises a tank body (51), a percolation plate (52) is fixedly connected to the middle of the tank body (51), a filtration bin (53) is formed above the percolation plate (52), a filtrate bin (54) is formed below the percolation plate (52), a top plate (55) is fixedly connected to the top of the sedimentation tank (5), a liquid pump (56) and a two-way air pump (57) are connected above the top plate (55), a liquid inlet of the liquid pump (56) is connected to the connecting branch pipe (41), and the two-way air pump (57) is connected to the nitrogen bin (225) via a connecting air pipe (571).

6. A catalytic cracking oil slurry filtration system as claimed in claim 5, characterized in that: A filter residue discharge port (531) is provided on one side of the filter bin (53), and a sealed door (532) is hingedly connected to the outer side of the filter residue discharge port (531).

7. A catalytic cracking oil slurry filtration system as claimed in claim 5, characterized in that: The top plate (55) is provided with an agitator (58), the agitator (58) comprising a stirring rod (581), the stirring rod (581) being rotatably connected in the filter bin (53), and the top plate (55) is connected with a stirring motor (582) for driving the stirring rod (581) to rotate.

8. A catalytic cracking oil slurry filtration system as claimed in claim 5, characterized in that: The top plate (55) is provided with a flocculator (59), the flocculator (59) comprising a medicine bin (591), the bottom of the medicine bin (591) being fixedly connected to the upper surface of the top plate (55) via a connecting rod (592), a medicine adding port (593) being provided on one side of the medicine bin (591), the bottom of the medicine bin (591) being connected to a feeding pipe (594), a spiral feeding rod (595) being rotatably connected inside the feeding pipe (594), the A feeding motor (596) for driving a spiral feeding rod (595) to rotate is connected to the top of the medicine bin (591); the lower end of the feeding pipe (594) is connected to a spray pipe (597); one end of the spray pipe (597) is connected to the nitrogen bin (225) via an air supply pipe (598); a control valve (599) is provided at the connection point; the other end of the spray pipe (597) passes through the top plate (55) to the top of the filter bin (53).

9. A catalytic cracking oil slurry filtration system as claimed in claim 5, characterized in that: A flocculator (59) is installed on the top plate (55), and the flocculator (59) comprises a medicine bin (591). The bottom of the medicine bin (591) is fixedly connected to the upper surface of the top plate (55) via a connecting rod (592). A medicine adding port (593) is provided on one side of the medicine bin (591). The bottom of the medicine bin (591) is connected to a feeding pipe (594), and a spiral feeding rod (595) is rotatably connected inside the feeding pipe (594). The top of the medicine bin (591) is connected to a feeding motor (596) for driving the spiral feeding rod (595) to rotate. The lower end of the feeding pipe (594) is connected to a spray pipe (597), and one end of the spray pipe (597) is connected to the nitrogen bin (225) via an air supply pipe (598), and a control valve six (599) is provided at the connection point.

10. A filtering method for a catalytic cracking oil slurry filtering system, based on a catalytic cracking oil slurry filtering system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, the oil slurry enters the upper annular tube (1) from the liquid inlet pipe (3), and flows into the lower annular tube (4) when the oil slurry flows through the filter (2). The flow rate of the oil slurry in the upper annular tube (1) is greater than the flow rate of the oil slurry in the lower annular tube (4). After the flowing oil slurry is filtered by the filter (2), solid particles accumulate in the lower annular tube (4). The lower annular tube (4) discharges the oil slurry with a large content of solid particles into the sedimentation tank (5) through the control valve 1 (42) on the connecting branch pipe (41); S2, the oil slurry with a large solid particle content is precipitated in the sedimentation tank (5) to remove the large solid particles, and the oil slurry with a small solid particle content is returned to the upper annular pipe (1) through the return pipe (6) for circulation; S3. The oil slurry filtered by the filter (2) is discharged into the liquid outlet pipe (7) through the liquid outlet branch pipe (71), and then discharged into the liquid outlet pipe (74) through the liquid outlet pump (73).

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