A closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke

Abstract

A closed transportation method for continuous graded treatment of petroleum coke and coal tar coke is used for the clean production of petroleum coke containing needle coke in delayed coking units. The coke and coke cutting water removed by hydraulic decoking fall into a buffer bin after screening and crushing, and are switched to be output to two primary drum dehydrators that serve as backup for each other. The large-size coke is initially dehydrated and sent to the dehydration bin for filtration and output; the coke cutting water and fine coke powder filtered out by the primary drum dehydrator enter the secondary drum dehydrator through the coke drainage ditch, and the concentrated fine coke powder slurry is sent to the coke powder drying system to output dry coke separately. The tail gas generated at various locations is discharged in compliance with the standards through the waste gas treatment system. The present invention can solve the problem of continuous graded closed treatment of coke, realize the separate transportation and storage of powdered coke and lump coke of different particle sizes and quality grades, have a small transportation load, a low coke crushing rate, a high utilization rate of coke cutting water, a low probability of powdered coke blocking pipes and bins, and is easy to transform the original device, reducing investment and operating consumption. The equipment can be switched online in an emergency to ensure continuous, stable and clean production.

Description

Technical Field

[0001] The invention relates to the technical field of clean production of petroleum coke and coal tar coke in petrochemical and coal chemical industries, and specifically to a closed transportation method for continuously and graded processing of petroleum coke and coal tar coke in a hydraulic decoking process of a delayed coking device containing a needle coke device. Background Art

[0002] The hydraulic decoking system of the delayed coking unit including the needle coke unit is traditionally open or semi-closed (cold coke water circulation treatment process) and coke pool water filter grab machine transfer method. During the water supply cooling, coke soaking and overflow process of the unit before decoking, a large amount of oily, sulfur-containing, powdery wastewater with a temperature of about 100°C and coke blocks with a large oil and water content will be generated. During decoking, high-temperature coke, cold coke water, overflow water, and coke cutting water are directly discharged into the coke pool. The coke powder, sulfide, VOCs and other harmful substances generated will also evaporate with the high-temperature steam, seriously polluting the surrounding ecological environment. Therefore, how to deal with coking waste gas, wastewater and dust, improve the operating environment and reduce pollution is a technical problem that needs to be solved urgently.

[0003] At present, there are several main types of closed decoking and transportation technologies at home and abroad: one is to use a tower bottom crusher to crush the coke during the decoking process, and then drop it into a mixing bin. The solid coke that has become coke slurry is continuously sent to the dehydration bin for dehydration through a large water-coke ratio mixed delivery pump, and then the dry coke of large and small particle sizes is mixed and discharged in a closed manner for loading and transportation; the other method is to let the coke fall into the dehydration bin for dehydration after being crushed at the bottom of the tower, or to change the original coke pool into a dehydration bin with a bottom filter. After the decoking is completed, the coke is dried and then transported in a closed manner using lifting equipment. However, the above-mentioned closed decoking and transportation technologies have the following defects:

[0004] 1. Continuous dehydration, transportation and transfer cannot be achieved during the decoking process, the transfer cycle is long, the equipment load is high, and the water and electricity power consumption is large.

[0005] 2. High-speed slurry pumps or high-speed lifting equipment are used in the coke transportation and lifting process, which increases the coke breakage rate and affects the quality grade of the coke products.

[0006] 3. It is impossible to separate cokes of different particle sizes and grades during the decoking process. Cokes of various particle sizes and quality grades are mixed together and cannot be graded for transportation and storage, which reduces the value of petroleum coke, especially needle coke, and increases the difficulty of subsequent separation processes.

[0007] 4. It is impossible to dehydrate large-size coke separately. The large amount of water in the water-coke mixed dehydration bin takes a long time to dehydrate. During the dehydration process, the filter screen cannot be continuously desilted and cleaned. Repeated filtering of fine powder often causes a large amount of fine coke powder in the dehydration bin to block the filter screen, making it difficult to discharge the coke from the bin. Especially when the coke pool dehydration method is adopted, the coke mud at the bottom of the coke pool is difficult to clean and inconvenient to repair, which often causes equipment failure.

[0008] 5. A single coke tower or needle coke tower needs to be independently equipped with a complete set of equipment. The key dehydration process cannot use online maintenance and emergency switching to meet emergency production in the event of equipment failure.

[0009] 6. It is necessary to change the design structure of the existing delayed coking unit derrick or replace the original equipment, which is difficult to install using the existing unit structure, resulting in a large footprint and high investment. Summary of the invention

[0010] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke, so as to solve the problem of continuous graded closed treatment of delayed coking petroleum coke units containing needle coke units, and realize the closed transportation and drying treatment of powder coke and lump coke of different quality grades.

[0011] To achieve the above-mentioned purpose of the invention, the bottom valve of the coke tower or the needle coke tower of the present invention is connected to a hydraulic lifting sealing sleeve for realizing a sealing connection with different forms of bottom valves. Below the hydraulic lifting sealing sleeve, a flow limiting valve for adjusting the coke outlet flow in the coke tower or the needle coke tower and preventing the blockage of subsequent processing caused by excessive instantaneous flow in the initial stage of decoking is connected to the hydraulic lifting sealing sleeve. The flow limiting valve, the transfer elbow, the screening conveyor, and the crusher are connected and installed in sequence. The flow limiting valve is supported on the foundation of the tower bottom platform. The outlets of the screening conveyor and the crusher are connected to the inlet of the buffer bin. The coke removed from the coke tower or the needle coke tower is connected to the coke cutting water. The screening conveyor separates most of the coke smaller than 200mm into the buffer bin in advance to reduce the workload of the crusher and the blockage of the feed. The coke larger than 200mm is conveyed into the crusher through the screening conveyor and crushed to less than 200mm before falling into the buffer bin. The elbow coke flushing port is connected to the anti-blocking coke flushing water pipe; the cold coke discharge pipe of the coke tower or needle coke tower is connected to the buffer bin, and the hot water in the cold coke process of the coke tower or needle coke tower before decoking and the small amount of coke carried enter the buffer bin for treatment, and the buffer bin is pre-washed; the buffer bin is equipped with an auxiliary coke flushing water pipe, which is formed under the joint action of the coke cutting water and the two auxiliary coke flushing water pipes. Hydraulic stirring prevents coke siltation in the buffer bin and facilitates its flow; slurry pump 1 connected to the primary water filter and slurry pump 4 connected to the sedimentation tank respectively send clarified water into the anti-blocking coke flushing water pipe and the buffer bin to assist in coke flushing; coke and coke cutting water removed from the coke tower or needle coke tower are screened and crushed by the screening conveyor and crusher before entering the buffer bin; the outlet of the buffer bin is connected to a three-way switching valve, which is connected to the blanking distributors in the two primary drum dehydrators. The three-way switching valve evenly outputs the coke slurry in the buffer bin through the blanking distributor to the two primary drum dehydrators that serve as backup for each other, so as to reduce the impact of unbalanced load on the normal operation of the primary drum dehydrators Once one of the primary drum dehydrators fails, it can automatically switch to the other primary drum dehydrator. The two primary drum dehydrators can also work at the same time to prevent the short-term unstable large flow shock in the hydraulic decoking process of the coke tower or needle coke tower. The low-speed rotating primary drum dehydrator will remove the large-diameter dehydrated coke larger than 8mm~200mm to reduce the coke crushing rate, and the large-diameter dehydrated coke will be dropped into the lifting device through the coke hopper of the primary drum dehydrator and then output to the bin device, and then transported into two or more independent dehydration bins through the bin device, and then dehydrated and filtered in the independent dehydration bins to output the graded coke products;

[0012] The primary drum dehydrator is installed on the primary water filter tank, and a primary coke powder scraper is arranged at the bottom of the primary water filter tank. The primary coke powder scraper scrapes the bottom coke into the primary coke collection pit. Under the action of water flow, the filtered coke cutting water and fine coke powder enter the secondary coke collection pit through the coke discharge ditch. The secondary drum dehydrator is used to dry the gathered coke powder in the secondary coke collection pit. The primary water filter tank is provided with an overflow channel connected to the coke discharge ditch.

[0013] The secondary drum dehydrator is installed on the secondary water filter tank. The bottom of the secondary drum dehydrator is scraped into the secondary coke collection pit by a secondary coke powder scraper. The fine coke powder slurry at the bottom of the secondary coke collection pit is lifted by a slurry pump and sent to the secondary drum dehydrator for dehydration and concentration, and then output to the coke powder drying system to output the coke powder finished product separately.

[0014] The dehydration bin, primary drum dehydrator, coke tower or needle coke tower, buffer bin, secondary drum dehydrator, sedimentation tank and the top of the coke cutting water tank are respectively connected to fans, so that the exhaust gas enters the exhaust gas treatment system for treatment; after decoking, the supernatant in the sedimentation tank is lifted to the coke cutting water tank for recycling through the coke cutting water lifting pump, and the coke cutting water tank is connected to the water inlet pipe of the high-pressure water pump of the hydraulic decoking system, and the overflowing coke water flows into the coke discharge ditch and assists in coking.

[0015] The screening conveyor is obliquely connected to the buffer bin through the crusher; the buffer bin is located outside the coke tower or the needle coke tower, or below the coke tower or the needle coke tower, and the height difference between the outlet of the three-way switching valve connected to the buffer bin outlet and the material distributor of the primary drum dehydrator is greater than one meter to ensure smooth discharge of the coke slurry.

[0016] The dehydration classification particle size of the primary drum dehydrator is 8-200mm, and the dehydration classification particle size of the secondary drum dehydrator is 0.6-8mm; a maintenance platform is provided beside the primary filter pool and the secondary filter pool below the primary drum dehydrator and the secondary drum dehydrator, and the pool depth is greater than two meters; a compressed air backflush device is respectively connected to the top of the primary drum dehydrator and the secondary drum dehydrator, and a pressure water backwash device is respectively connected and installed on the side of the primary drum dehydrator and the secondary drum dehydrator. The compressed air of the compressed air backflush device blows the coke powder blocked by the filter screen into the coke outlet hopper from the top of the primary drum dehydrator and the secondary drum dehydrator, and the pressure water backwash device flushes the blocked coke back into the primary drum dehydrator and the secondary drum dehydrator from the side, so as to ensure that the filter screen is cleaned in time during the dehydration process and improve the filtering efficiency of the primary drum dehydrator and the secondary drum dehydrator.

[0017] The dehydration output mode of the secondary drum dehydrator is hydraulic conveying or mechanical conveying. The hydraulic conveying mode is that the slurry pump 3 sends the concentrated coke slurry precipitated at the bottom of the sedimentation tank into the output pipe of the secondary drum dehydrator as the slag flushing power, and the mixed secondary drum filtered fine coke particles are sent to the coke powder drying system; mechanical conveying adopts a closed tube chain machine and a scraper machine to output to the coke powder drying system; the coke powder drying machine of the coke powder drying system is a vacuum belt filter, a belt filter press, a plate and frame filter press, a high-speed centrifuge or a dehydration bin.

[0018] There are two to four dehydration bins, which are provided with a lifting device and a bin separation device for separating different grades of coke into bins; the lifting device is a belt conveyor, a closed scraper conveyor, a bucket elevator, a tube chain conveyor or a screw conveyor.

[0019] The tower bottom valve connected above the hydraulic lifting sleeve is an automatic tower bottom gate valve, a semi-automatic tower bottom cover unloading machine, an electric bottom cover machine or a tower bottom cover unloading device.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The process method of the present invention can realize the continuous automated operation of closed decoking of petroleum coke (including needle coke), and can classify and seal the coke with different quality properties in the coke tower or needle coke tower according to the order of decoking operation and transport it in different time periods, dehydrate it in different warehouses, store it and output it, thus reducing the operation cycle, improving work efficiency, and being beneficial to improving the quality classification value of petroleum coke (including needle coke).

[0022] 2. Setting up a screening and crushing process can reduce the coke crushing load; setting up a two-stage low-speed drum grading and dehydration device can independently separate most of the coke powder smaller than 8 mm, and dry and output it separately, which can not only improve the grading quality grade of the proportion of ordinary petroleum coke powder, but also reduce the ablation rate of the subsequent calcination of needle coke powder, reduce the subsequent processing steps, and is beneficial to improving the particle size grading value of petroleum coke (including needle coke).

[0023] 3. Through the three-way switching valve set at the outlet of the buffer bin, the coke slurry in the buffer bin can be distributed to any one of the primary drum dehydrators as needed, so that they can work at the same time or one in use and one in reserve, ensuring emergency switching to the reserve when the drum equipment or other subsequent equipment fails.

[0024] 4. The coke slurry output by the primary drum dehydrator passes through the material distributor inside it, and the coke of different particle sizes can be evenly transported by hydraulic power to the entire length of the drum axis. The low-speed rotating primary drum dehydrator dehydrates and removes the coke with large particle size, which can reduce the coke breakage rate. The primary drum dehydrator is equipped with a compressed air backflush device and a pressure water backwash device, which can implement online cleaning of slag blockage to ensure its filtration efficiency. The drum filter can also be inspected and replaced during the decoking interval, which can maximize the normal operation of the drum and is conducive to the stable and efficient operation of the closed decoking system.

[0025] 5. The primary coke powder scraper installed at the bottom of the primary drum dehydrator filter tank can scrape the filtered fine coke powder into the coke collection pit at the bottom of the tank. By utilizing the height difference, the filtered coke powder enters the coke discharge ditch along with the coke cutting water and auxiliary coke flushing water, and flows into the coke collection pit through gravity flow and hydraulic impact for collection. The secondary drum dehydrator is used to filter out the fine coke powder again and send it to the coke powder drying system. The coke powder smaller than 8mm can be independently dehydrated and dried before output, reducing the blockage of the filter caused by repeated filtration of coke powder and classifying and utilizing coke resources of different particle sizes.

[0026] 6. After the waste gas collection pipelines are gathered together, the waste gas can be sent to the waste gas treatment system. After removing coke powder, moisture, and floating oil, the dry gas is input into the desulfurization system to remove mercaptans and hydrogen sulfide. Finally, the desulfurized dry gas containing a small amount of VOCs is sent to the heating furnace inlet duct for combustion treatment, thus completely realizing clean production.

[0027] 7. The closed transfer and grading treatment of petroleum coke (including needle coke) has a continuous and uniform conveying load, high utilization rate of coke cutting water, small investment, easy transformation of existing equipment, and simple equipment maintenance. It can effectively improve the quality value of petroleum coke, reduce investment and operating consumption, and can perform online emergency switching of equipment, reduce equipment shutdown, and ensure continuous, stable and clean production of delayed coking units. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a simplified process flow diagram of the present invention. DETAILED DESCRIPTION

[0029] like Figure 1As shown, the bottom valve 2 of the coke tower or the needle coke tower 1 of the present invention is connected to the flow limiting valve 36 via a hydraulic lifting sealing sleeve 37. The hydraulic lifting sealing sleeve 37 can realize a sealed connection with different forms of bottom valves 2 or various bottom cover machine outlets. The bottom valve 2 is an outsourced automatic bottom gate valve, a semi-automatic cover unloading machine, an electric bottom cover machine or a bottom cover unloading device; the flow limiting valve 36 can adjust the coke outlet flow in the coke tower or the needle coke tower 1, and prevent the subsequent treatment from being blocked due to excessive instantaneous flow in the initial stage of decoking. The flow limiting valve 36 is installed on the bottom platform of the coke tower or the needle coke tower 1, and is connected to the transfer elbow 4. The anti-blocking coke flushing water pipe 12 with a slurry pump 21 is connected to the corner of the transfer elbow 4. The coke punching port of the back plate is connected to assist coke punching, prevent coke precipitation and siltation, and increase the power of coke punching; the outlet end of the transfer elbow 4 is connected to the inlet end of the screening conveyor 33, and the upper outlet end of the screening conveyor 33 is connected to the inlet of the crusher 3. The screening conveyor 33 and the crusher 3 are installed on the top of the buffer bin 5, and the lower outlet ends of the screening conveyor 33 and the crusher 3 are connected to the inlet end of the buffer bin 5. The screening conveyor 33 can pre-separate most of the coke less than 200mm, reduce the workload and feed blockage of the crusher 3, and the coke larger than 200mm is transported into the crusher 3 through the screening conveyor 33 and falls into the buffer bin 5 after being crushed to 200mm. The buffer bin 5 is located at The coke tower or the needle coke tower 1 is located outside, or below, the coke tower or the needle coke tower 1, so as to facilitate the transformation and reduce the floor space; the buffer bin 5 is connected to two auxiliary coke flushing water pipes 27, and the coke and the coke cutting water removed by the coke tower or the needle coke tower 1 are respectively screened and crushed by the screening conveyor 33 and the crusher 3 and fall into the buffer bin 5, and hydraulic stirring is formed under the joint action of the coke cutting water and the two auxiliary coke flushing water pipes 27 to prevent the coke in the buffer bin 5 from silting up and flowing, causing the coke outlet to be blocked, and ensure that the coke and the coke cutting water in the buffer bin 5 are evenly mixed and output; the cold coke discharge pipe 7 of the coke tower or the needle coke tower 1 is connected to the buffer bin 5, and the cold coke hot water in the coke tower or the needle coke tower 1 before decoking and the hot water carrying the cold coke in the coke tower or the needle coke tower 1 before decoking are discharged. A small amount of coke enters the buffer bin 5 for dehydration, and the residual coke in the buffer bin 5 is flushed at the same time; the outlet of the buffer bin 5 is connected to the three-way switching valve 6, which automatically switches the output to two primary drum dehydrators 9 that are standby for each other. The three-way switching valve 6 can adjust the flow rate during normal operation. Once one of the primary drum dehydrators 9 fails, it can automatically switch to the other primary drum dehydrator 9. The two primary drum dehydrators 9 can also work at the same time to prevent the short-term instability in the hydraulic decoking process of the coke tower or the needle coke tower 1 and the large flow impact. The height difference between the three-way switching valve 6 and the material distributor 28 of the primary drum dehydrator 9 is greater than 1 meter, which can ensure smooth discharge of coke slurry;The coke slurry flowing out of the buffer bin 5 falls into the primary drum dehydrator 9 evenly through the material distributor 28, which can reduce the influence of the unbalanced load on the normal operation of the primary drum dehydrator 9. The primary drum dehydrator 9 rotating at a low speed drops the large-size dehydrated coke of 8-200 mm into the lifting device 10 through the coke discharge hopper 20 and outputs it to the bin device 11. The bin device 11 transports it into two or more independent dehydration bins 22. The finished coke is output after dehydration and filtration according to different grades of coke. Most of the powdered coke of 0.6-8 mm enters the secondary drum dehydrator through the coke discharge groove 35. The water collector 13 continuously separates and sends the coke powder to the coke powder drying system 24 for separate drying and output, so as to reduce the probability of subsequent dehydration and clogging the filter screen; the dehydration bin 22 is provided with a bin separator for dehydrating and outputting coke of different grades, and under the control of the intelligent control system, continuous coke particle size classification and quality classification can be achieved during the decoking process. The dehydration bin 22 is also provided with a conveying equipment lifting device 10 and a bin separator 11 for separating coke of different grades. The lifting device 10 is a belt conveyor, a closed scraper, a bucket elevator, a pipe chain machine or a screw conveyor. ;

[0030] The primary drum dehydrator 9 is provided with a compressed air backflush device 26 and a pressure water backwash device 29 on the outside. The compressed air backflush device 26 is connected to the top of the primary drum dehydrator 9 and can blow the coke powder blocked by the filter screen of the primary drum dehydrator 9 into the coke outlet hopper 20 from the top of the primary drum dehydrator 9. The pressure water backwash device 29 is installed on the side of the primary drum dehydrator 9 and is used for online backwashing of the screen of the primary drum dehydrator 9 to prevent the blockage of the coke powder and ensure that the filter screen is cleaned in time during the dehydration process, thereby improving the drum. Filtration efficiency: A primary water filter tank 30 is arranged below the primary drum dehydrator 9, and a maintenance platform is provided beside the tank. The tank depth is greater than two meters, so that a primary coke powder scraper 19 for preventing coke powder from silting up can be installed at the bottom of the primary water filter tank 30. An overflow channel 31 is arranged in the tank and connected to a coke discharge ditch 35 to balance the liquid level of the primary water filter tank 30 and assist in coke flushing. The primary coke powder scraper 19 scrapes the bottom coke into a primary coke collection pit 32. Under the action of the water flow, the filtered coke cutting water and fine coke powder enter the secondary coke collection pit 34 through the coke discharge ditch 35.

[0031] The secondary drum dehydrator 13 is installed on the secondary water filter 16. The bottom of the secondary drum dehydrator 13 uses the secondary coke powder scraper 14 arranged at the bottom of the secondary water filter 16 to scrape the bottom coke into the secondary coke collection pit 34 again. The fine coke powder of 0.6mm-8mm at the bottom of the secondary coke collection pit 34 is sent to the secondary drum dehydrator 13 for pre-dehydration through the slurry pump 15; the compressed air backwashing device 26 is connected above the secondary drum dehydrator 13, and the pressure water backwashing device 29 is installed on the side of the secondary drum dehydrator 13, which is used for online backwashing of the screen of the secondary drum dehydrator 13 to prevent the coke powder from clogging; the secondary water filter 16 The upper clarified liquid flows into the sedimentation tank 40, and the coke slurry gathered in the sedimentation tank 40 is sent to the output pipe 17 of the secondary drum dehydrator 13 again through the slurry pump 39 as the slag flushing power, and the fine coke particles of 0.6mm-8mm mixed with the secondary filtered are sent to the coke powder drying system 24 to output the dry coke powder product; the coke powder drying machine of the coke powder drying system 24 is a vacuum belt filter, a belt filter press, a plate and frame filter press, a high-speed centrifuge or a dehydration bin, which dries the concentrated coke slurry filtered by the secondary drum dehydrator 13, or directly transports the fine coke powder filtered by the secondary dehydration drum 13 to the dehydration bin 22 for drying.

[0032] The present invention uses two slurry pumps 21 connected to the primary water filter 30 and two slurry pumps 38 connected to the sedimentation tank 40 to send clarified water into the buffer bin 5 for coke washing and stirring and the anti-blocking coke washing water pipe 12 for coke washing. Under the joint action of the coke cutting water and the two auxiliary coke washing water pipes, hydraulic stirring is formed to prevent the coke in the buffer bin 5 from silting up and facilitate flow; the dewatering bin 22, the primary drum dehydrator 9, the coke tower or the needle coke tower 1, the buffer bin 5, the secondary drum dehydrator 13, the sedimentation tank 40, and the top of the coke cutting water tank 23 are respectively connected to the fan 8, so that the exhaust gas is respectively After entering the waste gas treatment system 25 for treatment and removing coke powder, moisture and floating oil, the dry gas is input into the desulfurization system to remove mercaptans and hydrogen sulfide. Finally, the desulfurized dry gas containing a small amount of VOCs is sent to the air inlet duct of the heating furnace for combustion treatment. The decoking process equipment is completely closed and all tail gas is discharged in compliance with the standards. After decoking, the supernatant in the sedimentation tank 40 is lifted to the coke cutting water tank 23 for recycling by the coke cutting water lifting pump 18. The coke cutting water tank 23 is connected to the water inlet pipe of the hydraulic decoking system high-pressure water pump 41. The overflowing coke water flows into the coke discharge ditch 35 and assists in coking.

Claims

1. A closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke, characterized in that: The bottom valve (2) of the coke tower or the needle coke tower (1) is connected to a hydraulic lifting sealing sleeve (37) for achieving a sealing connection with the bottom valve (2) of different forms. Below the hydraulic lifting sealing sleeve (37), a flow limiting valve (36) for adjusting the coke discharge flow rate in the coke tower or the needle coke tower (1) and preventing the subsequent processing from being blocked due to excessive instantaneous flow rate at the initial stage of decoking is connected to the hydraulic lifting sealing sleeve (37). The flow limiting valve (36), the transfer elbow (4), and the screening conveyor (3 3) and the crushers (3) are connected and installed in sequence, the flow limiting valve (36) is supported on the foundation of the tower bottom platform, the screening conveyor (33) and the crusher (3) outlets are connected to the inlet of the buffer bin (5), the coke cut off by the coke tower or the needle coke tower (1) and the coke cutting water are pre-separated into the buffer bin (5) by the screening conveyor (33) to reduce the workload of the crusher (3) and the feed blockage, and the coke larger than 200 mm is transported into the buffer bin (5) by the screening conveyor (33). The coke enters the crusher (3) and is crushed to less than 200 mm, then falls into the buffer bin (5). The coke flushing port of the transfer elbow (4) is connected to the anti-blocking coke flushing water pipe (12). The cold coke discharge pipe (7) of the coke tower or the needle coke tower (1) is connected to the buffer bin (5). The hot water in the cold coke process of the coke tower or the needle coke tower (1) before decoking and the small amount of coke carried enter the buffer bin (5) for treatment, and the buffer bin (5) is pre-washed. The buffer bin (5) is provided with an auxiliary coke flushing water pipe (27). The auxiliary coke-washing water pipe (27) forms hydraulic stirring under the joint action to prevent the coke from silting up in the buffer bin (5) and facilitate the flow; the slurry pump 1 (21) connected to the primary water filter tank (30) and the slurry pump 4 (38) connected to the sedimentation tank (40) respectively send clarified water into the anti-blocking coke-washing water pipe (12) and the buffer bin (5) to assist in coke-washing; the coke and the coke-cutting water removed from the coke tower or the needle coke tower (1) are screened and crushed by the screening conveyor (33) and the crusher (3) and then enter the buffer bin (5);The outlet of the buffer bin (5) is connected to a three-way switching valve (6), which is connected to the blanking distributors (28) in the two primary drum dehydrators (9). The three-way switching valve (6) evenly outputs the coke slurry in the buffer bin (5) to the two primary drum dehydrators (9) serving as backup for each other through the blanking distributor (28), so as to reduce the influence of unbalanced load on the normal operation of the primary drum dehydrators (9). Once one of the primary drum dehydrators (9) fails, it automatically switches to the other primary drum dehydrator (9), or the two primary drum dehydrators (9) fail at the same time. Working to prevent short-term unstable large flow shock in the hydraulic decoking process of the coke drum or needle coke drum (1), the low-speed rotating primary drum dehydrator (9) removes large-diameter dehydrated coke larger than 8 mm to 200 mm to reduce the coke crushing rate, and the large-diameter dehydrated coke is dropped into the lifting device (10) through the coke outlet hopper (20) of the primary drum dehydrator (9) and then output to the bin device (11), and then transported into two or more independent dehydration bins (22) through the bin device (11), and then dehydrated and filtered through the independent dehydration bins (22) to output the graded coke products; The primary drum dehydrator (9) is installed on the primary water filter (30). A primary coke powder scraper (19) is provided at the bottom of the primary water filter (30). The primary coke powder scraper (19) scrapes the bottom coke into the primary coke collection pit (32). Under the action of the water flow, the filtered coke water and fine coke powder enter the secondary coke collection pit (34) through the coke discharge groove (35). The secondary drum dehydrator (13) performs drying pretreatment on the collected coke powder in the secondary coke collection pit (34). The primary water filter (30) is provided with an overflow channel (31) connected to the coke discharge groove (35); The secondary drum dehydrator (13) is installed on the secondary water filter (16). The bottom of the secondary drum dehydrator (13) is equipped with a secondary coke powder scraper (14) to scrape the bottom coke into the secondary coke collection pit (34). The fine coke powder slurry at the bottom of the secondary coke collection pit (34) is lifted by a slurry pump (15) and sent to the secondary drum dehydrator (13) for dehydration and concentration and then output to the coke powder drying system (24) to output the coke powder product separately. The tops of the dehydration bin (22), the primary drum dehydrator (9), the coke tower or the needle coke tower (1), the buffer bin (5), the secondary drum dehydrator (13), the sedimentation tank (40), and the coke cutting water tank (23) are respectively connected to the fan (8), so that the waste gas enters the waste gas treatment system (25) for treatment. After decoking is completed, the supernatant in the sedimentation tank (40) is lifted to the coke cutting water tank (23) by the coke cutting water lifting pump (18) for recycling. The coke cutting water tank (23) is connected to the water inlet pipe of the high-pressure water pump (41) of the hydraulic decoking system, and the overflowed coke water flows into the coke discharge ditch (35) to assist in coking.

2. The closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke according to claim 1, characterized in that: The screening conveyor (33) is obliquely connected to the buffer bin (5) via the crusher (3); the buffer bin (5) is located outside the coke tower or the needle coke tower (1), or below the coke tower or the needle coke tower (1); the height difference between the outlet of the three-way switching valve (6) connected to the outlet of the buffer bin (5) and the material distributor (28) of the primary drum dehydrator (9) is greater than one meter, so as to ensure smooth discharge of the coke slurry.

3. The closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke according to claim 1, characterized in that: The dehydration classification particle size of the primary drum dehydrator (9) is 8-200 mm, and the dehydration classification particle size of the secondary drum dehydrator (13) is 0.6-8 mm; a maintenance platform is provided on the side of the primary filter pool (30) and the secondary filter pool (16) below the primary drum dehydrator (9) and the secondary drum dehydrator (13), and the pool depth is greater than two meters; a compressed air backwash device (26) is respectively connected to the top of the primary drum dehydrator (9) and the secondary drum dehydrator (13), and a pressure water backwash device (29) is respectively connected and installed on one side. On the side of the secondary drum dehydrator (9) and the secondary drum dehydrator (13), compressed air from the compressed air back-blowing device (26) blows the coke powder blocked by the filter screen into the coke outlet hopper (20) from above the primary drum dehydrator (9) and the secondary drum dehydrator (13), and the pressure water backwashing device (29) flushes the blocked coke back into the primary drum dehydrator (9) and the secondary drum dehydrator (13) from the side, so as to ensure that the filter screen is cleaned in time during the dehydration process, thereby improving the filtering efficiency of the primary drum dehydrator (9) and the secondary drum dehydrator (13).

4. The closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke according to claim 1, characterized in that: The dewatering output mode of the secondary drum dehydrator (13) is hydraulic conveying or mechanical conveying. The hydraulic conveying mode is that the slurry pump three (39) sends the concentrated coke slurry precipitated at the bottom of the sedimentation tank (40) into the output pipe (17) of the secondary drum dehydrator (13) as the slag flushing power, and mixes the fine coke particles filtered by the secondary drum and sends them to the coke powder drying system (24); the mechanical conveying adopts a closed tube chain machine and a scraper machine to output to the coke powder drying system (24); the coke powder drying machine of the coke powder drying system (24) is a vacuum belt filter, a belt filter press, a plate and frame filter press, a high-speed centrifuge or a dewatering bin.

5. The closed dehydration and transportation method for continuous graded treatment of petroleum coke and coal tar coke according to claim 1, characterized in that: There are two to four dehydration bins (22), which are provided with a lifting device (10) and a bin separation device (11) for separating coke of different grades into bins; the lifting device (10) is a belt conveyor, a closed scraper conveyor, a bucket elevator, a tube chain conveyor or a screw conveyor.

6. A closed transportation method for continuous graded treatment of petroleum coke and coal tar coke according to claim 1, characterized in that: The tower bottom valve (2) connected above the hydraulic lifting sealing sleeve (37) is an automatic tower bottom gate valve, a semi-automatic tower bottom cover unloading machine, an electric tower bottom cover unloading machine or a tower bottom cover unloading device.

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