An anti-coking device and separation system for ebullated bed residue hydrogenation

Abstract

A coking prevention device and separation system for ebullated bed residue oil hydrogenation belongs to the field of residue oil hydrogenation, and includes an electrostatic separation zone with relatively arranged upper and lower plates, wherein the upper and lower plates separate the electrostatic separation zone into an upper light oil discharge zone, a middle electric field zone and a lower heavy oil zone, and the upper plate surface is provided with through holes for light oil to pass through; the lower plate is provided with heavy oil channels that pass through the heavy oil zone; a sedimentation separation zone is provided below the electrostatic separation zone, and the heavy oil zone is connected to the bottom of the sedimentation separation zone through a heavy component conveying pipe. The anti-coking device of the present invention can remove asphaltene, coke particles and other easily coked substances precipitated in the product in advance, thereby slowing down the coking tendency in subsequent devices; it has the advantages of low energy consumption, simple operation, long operating cycle, etc., and can greatly reduce the coking phenomenon in the ebullated bed hydrogenation process, which is conducive to further improvement of the residue oil conversion rate.

Description

Technical Field

[0001] The present invention relates to the field of ebullated bed residue oil hydrogenation, in particular to an anti-coking device and a separation system for ebullated bed residue oil hydrogenation. Background Art

[0002] Ebullated-bed residue hydrocracking technology is a key process for deep processing and efficient, clean conversion of heavy, low-quality crude oil. It is capable of processing low-quality feedstocks with high metal content, high sulfur content, and high carbon residue, as well as oil sands bitumen. The unit offers flexible operation and a long run cycle, and can improve product quality and residue conversion by adjusting operating conditions and catalyst addition. In recent years, with strong demand in the downstream chemical market, the high-conversion ebullated-bed residue hydrocracking process has seen rapid development. Its advantages, such as strong feedstock adaptability, high light oil yield, and clean, environmentally friendly processing, have led to its increasing popularity among refineries.

[0003] Due to the high reaction temperature and poor feedstock properties of the ebullated-bed residue hydrocracking process, the unit is prone to sludge formation at high conversion rates, leading to coking in the reactor and downstream equipment. Scaling and blockage of equipment and pipelines is the primary cause of shutdowns in ebullated-bed hydrocracking units and has become one of the main factors limiting ebullated-bed unit operations.

[0004] The ebullated-bed residue hydrocracking process suffers from coking issues, which, on the one hand, limits the residue conversion rate, and on the other hand, restricts the vacuum distillation temperature, resulting in a high level of wax oil components in the unconverted oil. Coking also greatly increases the difficulty of operating the unit. Equipment, pipelines, valves, and instruments containing heavy oil need to be flushed with flushing oil to ensure that valves do not stick and instrument lines are not clogged. The vacuum tower of the distillation system requires an average shutdown for maintenance every 6-12 months. During this maintenance, the unit load drops significantly, energy consumption increases, and the feedstock of downstream units is affected, which in turn affects the processing load of the entire plant. The vacuum tower bottom heat exchanger has a very short cleaning cycle. Frequent cleaning not only increases maintenance costs, but also makes high-temperature, low-autoignition-point oils prone to leakage and ignition, posing a major safety hazard.

[0005] In order to avoid or delay system coking and extend the operation cycle of the device as much as possible, technology patent holders, design units and production companies have proposed corresponding solutions from the aspects of process condition optimization, process flow design, equipment and instrument selection, etc.:

[0006] For example, the catalyst is selected according to the properties of the processed residual oil, but one catalyst cannot be applied to process all different residual oils. Generally, one catalyst is only suitable for processing one or several types of residual oils. When the raw materials change, the adaptability of the device is poor.

[0007] For example, HTI has invented a liquid catalyst called HCAT, which can reduce catalyst coking and increase the hydroconversion rate of residual oil. This catalyst has a good effect on low-conversion units, but has little effect on units with conversion rates above 80%.

[0008] There are also attempts to use micro-interface enhancement technology to reduce the hydrogen entering the reactor from the millimeter level to the micron level, thereby improving the gas-liquid interface and mass transfer efficiency, but this technology has not been applied industrially;

[0009] There are also methods to set flushing oil and flushing hydrogen at the parts prone to coking, such as measuring instruments, control valves, and instrument leads, so as to flush the pipelines and equipment in time when the device is shut down or a part of the pipeline is cut out. However, this method is relatively cumbersome to operate.

[0010] Other measures, such as installing switchable filters in the main process and optimizing the heat exchanger structure, have certain effects, but are not significant in alleviating the coking phenomenon in the boiling bed residue oil hydrotreating process system and extending the operating cycle of the unit. Summary of the Invention

[0011] The present invention aims to provide an anti-coking device and a separation system for ebullated-bed residue oil hydrogenation, which improves system stability by removing easily coked components in the reaction products, significantly reduces the coking tendency of various parts of the device in the product separation system, and is conducive to the long-term stable operation of the ebullated-bed residue oil hydrogenation device. On the premise of ensuring the long-term stable operation of the device, the light oil yield and economic benefits of the refinery are further improved.

[0012] The technical solution adopted by the present invention to achieve the above technical objectives is as follows: an anti-coking device for ebullating bed residue oil hydrogenation, comprising an electrostatic separation zone having upper and lower plates arranged opposite to each other. The upper plate is charged, thereby forming an electric field zone between the upper and lower plates. Residual oil enters the electric field zone, and light oil purified by the electric field is discharged through the top of the electrostatic separation zone. The upper and lower plates separate the electrostatic separation zone into an upper light oil discharge zone, a middle electric field zone, and a lower heavy oil zone. Through holes for light oil to pass through are distributed on the surface of the upper plate; heavy oil channels are distributed on the lower plate to pass through the heavy oil zone.

[0013] A sedimentation separation zone is provided below the electrostatic separation zone, and the heavy oil zone is connected to the bottom of the sedimentation separation zone through a heavy component conveying pipe, so that the heavy oil in the heavy oil zone is introduced into the sedimentation separation zone, and an impurity oil discharge port is provided at the bottom of the sedimentation separation zone.

[0014] As an optimized solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, there is a gap between the edges of the upper and lower electrode plates and the inner side wall of the electrostatic separation zone to form an edge channel.

[0015] As another optimization solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, an insulating layer I is filled between the edges of the upper and lower electrode plates and the inner side walls of the electrostatic separation zone.

[0016] As another optimization solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, the upper surface of the upper electrode plate is covered with an insulating layer II to prevent the formation of an electric field in the light oil discharge area.

[0017] As another optimization scheme for the above-mentioned anti-coking device for boiling bed residue oil hydrogenation, the upper electrode plate is connected to the top of the electrostatic separation zone through a suspension rod, and the top end of the suspension rod extends out of the electrostatic separation zone and is connected to the high-voltage power supply device, and the top end of the suspension rod is closed by an insulating cover.

[0018] As another optimization solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, the lower electrode plate is arranged to be inclined from one side to the other side, and the heavy oil channel is located on the lower side.

[0019] As another optimization solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, the bottom of the lower electrode plate is supported by multiple supporting legs, so that the lower electrode plate forms an inclined surface.

[0020] As another optimization solution for the above-mentioned anti-coking device for boiling bed residue oil hydrogenation, a liquid suction pipe is provided at the top of the sedimentation separation zone, which is connected to the liquid inlet of the backwash pump. A backwash pipe is provided on the liquid outlet of the backwash pump, and the end of the backwash pipe extends to a position on the upper surface of the lower electrode plate opposite to the heavy oil channel.

[0021] As another optimization scheme for the above-mentioned anti-coking device for boiling bed residue oil hydrogenation, the sedimentation and separation zone includes a closed tank body, and the tank body is divided into a sedimentation zone, a transition zone and a light oil zone from bottom to top, wherein the height of the sedimentation zone accounts for 60-80% of the sedimentation and separation zone, and the width of the transition zone gradually increases from bottom to top, with the bottom flush with the sedimentation zone and the top flush with the light oil zone.

[0022] As another optimization solution for the above-mentioned anti-coking device for ebullated bed residue oil hydrogenation, the temperature difference between the electrostatic separation zone and the sedimentation separation zone and the temperature of the residue oil when entering the electric field zone is controlled at 5-10°C.

[0023] A system for separating products from hydrogenated products of an ebullated bed residue oil. The reaction products of the hydrogenated product of the ebullated bed residue oil are first introduced into a hot high-pressure separator to separate hydrogen and reaction oil gas. The hot oil gas is cooled by heat exchange and then introduced into a cold high-pressure separator to further separate oil gas and hydrogen. The separated hydrogen enters a circulating hydrogen desulfurization device for desulfurization and then participates in the hydrogenation reaction again as circulating hydrogen. The oil phase separated at the bottom of the hot high-pressure separator enters a hot low-pressure separator. The gas phase separated by the hot low-pressure separator is mixed with the oil phase at the bottom of the cold high-pressure separator and enters a cold low-pressure separator. The cold low-pressure separator separates acid gas and sends it to an acid gas treatment device. The oil phase at the bottom is mixed with the oil phase separated by the hot low-pressure separator and sent to a normal pressure fractionation tower to fractionate the product. The atmospheric residue produced by dry gas, naphtha and diesel enters the vacuum distillation tower to separate the vacuum wax oil and the unconverted oil at the bottom of the tower; the atmospheric residue produced by the atmospheric fractionation tower is first passed through the above-mentioned anti-coking device for treatment, and the impurity components are separated, and the light oil produced is then sent to the vacuum distillation tower; or, the oil phase at the bottom of the cold low-pressure separator is mixed with the oil phase separated by the hot low-pressure separator, and then first passed through the above-mentioned anti-coking device for treatment, and the impurity components are separated, and the light oil produced is then sent to the atmospheric fractionation tower; or, the oil phase separated at the bottom of the hot high-pressure separator is first passed through the above-mentioned anti-coking device for treatment, and the impurity components are separated, and the light oil produced then enters the hot low-pressure separator.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The anti-coking device of the present invention can remove asphaltene, coke particles and other coking substances precipitated from the product in advance, thereby reducing the coking tendency in subsequent devices. It has the advantages of low energy consumption, simple operation, and long operating cycle. It can also significantly reduce the coking phenomenon in the ebullated bed hydrogenation process, which is conducive to further improving the conversion rate of residual oil.

[0026] 2) The present invention combines the action of an electric field with that of sedimentation. The electric field moves the easily coked components in the residual oil downward, passing through the lower plate and entering the sedimentation separation zone. In the sedimentation separation zone, the components are further stratified. The light oil produced by stratification is extracted to wash the lower plate, so that the easily coked components deposited on the surface will not accumulate in the electric field zone, thereby ensuring the long-term operation of the device, reducing the energy loss of the electric field, and improving the impurity removal effect.

[0027] 3) The present invention adopts a combination of an upper electrostatic separation zone and a lower sedimentation separation zone, and the lower electrode plate is set at an angle, supplemented by a backwashing method of the surface of the lower electrode plate with light oil in the sedimentation separation zone, to solve the problems of weakened electric field strength between the electrode plates, increased energy consumption, and reduced purification efficiency of heavy components caused by the deposition of heavy components on the lower electrode plate; at the same time, the presence of the sedimentation separation zone allows the heavy components to settle downward, away from the electric field area, reducing the current in the electric field area, thereby reducing the energy consumption of the device, achieving continuous operation and stable operation, and ensuring long-term, continuous operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of an embodiment of the anti-coking device of the present invention;

[0029] Figure 2 This is a schematic diagram of another embodiment of the anti-coking device of the present invention;

[0030] Figure 3 Schematic diagram of an implementation of the upper plate;

[0031] Figure 4 Schematic diagram of an implementation of the lower plate;

[0032] Figure 5 A schematic diagram of the distribution of the support legs on the bottom surface of the lower plate;

[0033] Figure 6 A schematic diagram of an embodiment of the separation system of the present invention;

[0034] Figure 7 A schematic diagram of another embodiment of the separation system of the present invention;

[0035] Figure 8 A schematic diagram of another embodiment of the separation system of the present invention;

[0036] Figure 9 It is a structural diagram of Comparative Example 1;

[0037] Figure 10 It is a structural diagram of Comparative Example 2;

[0038] Figure 11 It is a structural diagram of Comparative Example 3;

[0039] Figure 1: Electrostatic separation zone, 101, light oil discharge zone, 102, electric field zone, 103, heavy oil zone, 104, heavy component conveying pipe, 105, light oil discharge pipe, 106, insulation layer I, 2, upper plate, 201, suspension rod, 202, insulation member, 203, insulation cover, 204, insulation layer II, 3, lower plate, 301, heavy oil channel, 302, support leg, 4, oil inlet pipe, 5, high voltage power supply device, 6, sedimentation separation zone, 601, impurity oil discharge port, 602, sedimentation zone, 603, Transition zone, 604, light oil zone, 7, backwash pump, 701, suction pipe, 702, backwash pipe, 801, hot high-pressure separator, 802, cold high-pressure separator, 803, hot low-pressure separator, 804, cold low-pressure separator, 805, circulating hydrogen desulfurization device, 806, anti-coking device, 807, atmospheric pressure fractionation tower, 808, vacuum distillation tower, A, boiling bed residue oil hydrogenation reaction product, B, circulating hydrogen, C, acid gas, D, dry gas, E, naphtha, F, diesel, G, vacuum wax oil, H, unconverted oil, I, impurity components. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further elaborated in detail below with reference to specific embodiments. Parts not explained in the following embodiments of the present invention, such as the hot high-pressure separator, the hot low-pressure separator, the cold high-pressure separator, the cold low-pressure separator, the circulating hydrogen desulfurization device, the vacuum distillation tower, the atmospheric pressure fractionation tower, the backwash pump, the high-voltage power supply device, etc., should be regarded as prior art known or should be known to those skilled in the art.

[0041] Example 1

[0042] A coking prevention device for ebullated bed residue oil hydrogenation, such as Figure 1 and 2 As shown, it includes an electrostatic separation area 1 with an upper plate 2 and a lower plate 3 arranged opposite to each other. The electrostatic separation area 1 is actually a closed cylindrical structure. The upper plate 2 and the lower plate 3 are both circular plate-like members arranged horizontally. Figure 3 、 Figure 4 and Figure 5As shown, the lower electrode plate 3 is fixedly connected to the bottom of the electrostatic separation zone 1, and the upper electrode plate 2 is hoisted below the top of the electrostatic separation zone 1. The upper electrode plate 2 is charged, thereby forming an electric field zone 102 between the upper and lower electrode plates. The lower electrode plate 3 and the shell of the electrostatic separation zone 1 are grounded. The electric field strength of the electric field zone 102 is generally 100-30000V / cm, preferably 500-20000V / cm. The residual oil enters the electric field zone 102, and the light oil purified by the electric field is discharged through the top of the electrostatic separation zone 1. An oil inlet pipe 4 is set in the electric field zone 102, and the end of the oil inlet pipe 4 extends into the middle of the electric field zone 102, and at the end A plurality of oil inlet holes are distributed within a certain distance, so that the residual oil can be uniformly introduced into the electrostatic separation zone 1. A light oil discharge pipe 105 is provided on the top of the electrostatic separation zone 1, and the light oil is discharged from the light oil discharge pipe 105. The residence time of the residual oil in the electric field zone 102 is 0.5-4 hours, preferably 0.5-2 hours. The upper plate 2 and the lower plate 3 separate the electrostatic separation zone 1 into the upper light oil discharge zone 101, the middle electric field zone 102 and the lower heavy oil zone 103. The surface of the upper plate 2 is provided with through holes for the light oil to pass through. Generally, the through holes are uniformly arranged in a circle around the position near the edge of the upper plate 2 ( Figure 3 The lower plate 3 is provided with a heavy oil channel 301 penetrating the heavy oil region 103, and the heavy oil channel 301 is a through groove, such as Figure 4 and 5 As shown, the surface of the lower plate 3 gradually decreases from the edge toward the heavy oil channel 301;

[0043] The electrostatic separation zone 1 is provided with a sedimentation separation zone 6 below. The sedimentation separation zone 6 is actually a closed tank structure. The sedimentation separation zone 6 can be an integrated structure with the electrostatic separation zone 1 or can be an independent and separate structure. Figure 1 and Figure 2 The structure shown is a separate structure, and the heavy oil area 103 is connected to the bottom of the sedimentation separation area 6 through a heavy component delivery pipe 104, so that the heavy oil in the heavy oil area 103 is introduced into the sedimentation separation area 6. In order to facilitate the heavy component to better enter the sedimentation separation area 6, the bottom of the heavy oil area 103 can be made into a conical shape, such as Figure 1 and Figure 2 As shown, the heavy component delivery pipe 104 is located at the lowest point of the conical structure, and an impurity oil discharge outlet 601 is provided at the bottom of the sedimentation separation zone 6. The impurity oil discharge outlet 601 is located at the lowest point of the sedimentation separation zone 6, and a valve is provided on it to control the discharge outlet to intermittently discharge the impurity oil. The frequency of discharge is adjusted according to actual conditions.

[0044] In this embodiment, the upper surface of the upper electrode plate 2 is covered with an insulating layer II 204 to prevent the formation of an electric field in the light oil discharge area 101;

[0045] In this embodiment, the upper electrode plate 2 is connected to the top of the electrostatic separation zone 1 via a suspension rod 201, and an insulating member 202 is provided between the suspension rod 201 and the top shell of the electrostatic separation zone 1. The top end of the suspension rod 201 extends out of the electrostatic separation zone 1 and is connected to the high-voltage power supply device 5. The top end of the suspension rod 201 is sealed by an insulating cover 203.

[0046] In this embodiment, the temperature difference between the temperature in the electrostatic separation zone 1 and the sedimentation separation zone 6 and the temperature of the residual oil when it enters the electric field zone 102 is controlled to be 5-10°C.

[0047] The above embodiments are basic implementations of the present invention, and further improvements, optimizations, and limitations can be made based on the above to obtain the following embodiments:

[0048] Example 2

[0049] This embodiment is an improvement on the embodiment 1. Its main structure is the same as that of the embodiment 1. The improvement is as follows: Figure 2 As shown, there is a gap between the edges of the upper plate 2 and the lower plate 3 and the inner wall of the electrostatic separation zone 1, forming an edge channel. At this time, an electric field is also formed between the edge of the upper plate 2 and the side wall of the electrostatic separation zone 1, which can also separate the impurities that may exist in the light oil passing through the edge channel.

[0050] Example 3

[0051] This embodiment is another improved solution based on embodiment 1. Its main structure is the same as that of embodiment 1. The improvement is as follows: Figure 1 As shown, an insulating layer I 106 is filled between the edges of the upper plate 2 and the lower plate 3 and the inner wall of the electrostatic separation zone 1. At this time, the light oil discharge zone 101, the middle electric field zone 102 and the lower heavy oil zone 103 are completely isolated from each other. Light oil can only enter the light oil discharge zone 101 through the through holes on the upper plate 2, and heavy oil can only enter the heavy oil zone 103 through the heavy oil channel 301 on the lower plate 3.

[0052] Example 4

[0053] This embodiment is another improvement on the basis of Example 1. Its main structure is the same as that of Example 1, with the improvement being that the lower electrode plate 3 is tilted from one side to the other, and the heavy oil channel 301 is located on the lower side. The tilt angle generally does not exceed 45°, and is preferably 2-15°.

[0054] In this embodiment, the bottom of the lower plate 3 is supported by a plurality of supporting legs 302. Figure 5The figure shows two short support legs and one long support leg distributed in a triangle, with the two short support legs on the same side and the long support leg on the other side, so that the lower electrode plate 3 forms an inclined surface. At this time, the heavy oil channel 301 is located between the two short support legs. The heavy oil channel 301 is a V-shaped through groove, with the V-shaped tip at the center of the circular lower electrode plate 3 and the bottom end at the edge of the circular lower electrode plate 3.

[0055] Example 5

[0056] This embodiment is another improved solution based on embodiment 1. Its main structure is the same as that of embodiment 1. The improvement is as follows: Figure 1 and Figure 2 As shown, the top of the sedimentation and separation zone 6 is provided with a liquid suction pipe 701, which is connected to the liquid inlet of the backwash pump 7. The end of the liquid suction pipe 701 extends into the sedimentation and separation zone 6 near the top. A backwash pipe 702 is provided on the liquid outlet of the backwash pump 7, and the end of the backwash pipe 702 extends to the position opposite to the heavy oil channel 301 on the upper surface of the lower electrode plate 3. The backwash pump 7 extracts the light oil formed after sedimentation and separation in the sedimentation and separation zone 6 and sprays it toward the heavy oil channel 301, thereby flushing the upper surface of the lower electrode plate 3 and preventing heavy components from accumulating on the lower electrode plate 3.

[0057] Example 6

[0058] This embodiment is another improved solution based on embodiment 1. Its main structure is the same as that of embodiment 1. The improvement is as follows: Figure 1 and Figure 2 As shown, the sedimentation and separation zone 6 includes a closed tank body, which is generally a cylindrical tank body, and the tank body is divided into a sedimentation zone 602, a transition zone 603 and a light oil zone 604 from bottom to top, wherein the height of the sedimentation zone 602 accounts for 60-80% of the sedimentation and separation zone 6, and the width of the transition zone 603 gradually increases from bottom to top, with the bottom flush with the sedimentation zone 602 and the top flush with the light oil zone 604.

[0059] Example 7

[0060] A system for separating products from residual oil hydrogenation in an ebullated bed. The product A of the residual oil hydrogenation reaction in an ebullated bed is first introduced into a hot high-pressure separator 801 to separate hydrogen and reaction oil gas. The hot oil gas is cooled by heat exchange and then introduced into a cold high-pressure separator 802 to further separate oil gas and hydrogen. The separated hydrogen enters a circulating hydrogen desulfurization device 805 for desulfurization and then participates in the hydrogenation reaction again as circulating hydrogen B. The oil phase separated at the bottom of the hot high-pressure separator 801 enters a hot low-pressure separator 803. The gas phase separated by the hot low-pressure separator 803 is mixed with the oil phase at the bottom of the cold high-pressure separator 802 and enters a cold low-pressure separator 804. The cold low-pressure separator 805 is used for desulfurization. 04 separates the acid gas C and goes to the acid gas treatment device. The oil phase at the bottom is mixed with the oil phase separated by the hot low-pressure separator 803 and sent to the atmospheric fractionation tower 807 to fractionate dry gas D, naphtha E and diesel F. The resulting atmospheric residue enters the vacuum distillation tower 808 to separate vacuum wax oil G and unconverted oil H at the bottom of the tower. The atmospheric residue produced by the atmospheric fractionation tower 807 is first passed through the anti-coking device 806 of the above-mentioned Examples 1-7 for treatment to separate the impurity component I (this component I is the impurity oil intermittently discharged through the impurity oil discharge port 601). The resulting light oil is then sent to the vacuum distillation tower 808. Figure 6 as shown; or Figure 7 As shown, the oil phase at the bottom of the cold low-pressure separator 804 is mixed with the oil phase separated by the hot low-pressure separator 803, and then passed into the anti-coking device 806 of the above-mentioned embodiment 1-7 for treatment to separate the impurity component I (this component I is the impurity oil intermittently discharged through the impurity oil discharge port 601), and the resulting light oil is then sent to the atmospheric pressure fractionation tower 807; or, as shown Figure 8 As shown, the oil phase separated from the bottom of the hot high-pressure separator 801 is first passed into the anti-coking device 806 of the above-mentioned embodiment 1-7 for treatment, and the impurity component I is separated (this component I is the impurity oil intermittently discharged through the impurity oil discharge port 601), and the resulting light oil then enters the hot low-pressure separator 803.

[0061] In order to verify the effect of the present invention, the following comparative experiment was performed:

[0062] Anti-coking device A, its structure refers to Figure 1 The lower electrode plate 3 is tilted and has a sedimentation separation zone 6 with a special structure and a backwash pump 7;

[0063] Anti-coking device B, its structure refers to Figure 2 , which differs from the anti-coking device A in that there is a channel between the edges of the upper and lower plates and the inner wall of the electrostatic separation zone 1;

[0064] Anti-coking device C, its structure refers to Figure 9 , which differs from the anti-coking device B in that the lower electrode plate 3 is arranged horizontally and no sedimentation separation zone 6 is provided;

[0065] Anti-coking device D, its structure refers to Figure 10 , which differs from the anti-coking device B in that the lower electrode plate 3 is arranged horizontally, and the shape of the sedimentation separation zone 6 is an integral cylindrical shape with equal diameter;

[0066] Anti-coking device E, its structure refers to Figure 11 , which differs from the anti-coking device B in that no sedimentation separation zone 6 is provided, but the lower electrode plate 3 has the same inclination angle as the lower electrode plate 3 in the anti-coking device B;

[0067] Experimental Example 1

[0068] A coking prevention treatment process for separating products from ebullated bed residue oil hydrogenation products comprises the following steps:

[0069] (1) Test using anti-coking device A;

[0070] (2) The atmospheric residue oil was heated to 365°C and transported to the anti-coking device A for treatment. The electric field applied by the device was a DC electric field with an electric field strength of 10,000 V / cm. The residence time of the reaction product in the anti-coking device was 0.5 h.

[0071] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0072] (4) Extract the impurities using n-heptane solvent and analyze the content of n-heptane-insoluble matter in the impurities.

[0073] Experimental Example 2:

[0074] A coking prevention treatment process for separating products from ebullated bed residue oil hydrogenation products comprises the following steps:

[0075] (1) Test using anti-coking device B;

[0076] (2) The atmospheric residue oil is heated to 365°C and transported to the anti-coking device B for treatment. The electric field applied by the device is a DC electric field with an electric field strength of 15000 V / cm. The residence time of the reaction product in the anti-coking device is 1 hour.

[0077] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0078] (4) Extract the impurities using n-heptane solvent and analyze the content of n-heptane-insoluble matter in the impurities.

[0079] Experimental Example 3:

[0080] A method for preventing coking in a residual oil hydrogenation product separation process in an ebullated bed comprises the following steps:

[0081] (1) Test using anti-coking device B;

[0082] (2) The atmospheric residue oil is heated to 365°C and transported to the anti-coking device B for treatment. The electric field applied by the device is a DC electric field with an electric field strength of 15000 V / cm. The residence time of the reaction product in the anti-coking device is 2 hours;

[0083] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0084] (4) Extract the impurities using n-heptane solvent and analyze the content of n-heptane-insoluble matter in the impurities.

[0085] Comparative Example 1

[0086] The atmospheric residue oil was heated to 365°C and filtered through a filter with a pore size of 5 μm. The time taken for the pressure in the filtration system to rise to 0.8 MPa was recorded.

[0087] Table 1 Effects of changes in test conditions

[0088] Serial number Oil sample Filter clogging time, h <![CDATA[IC7 content in impurities, %]]> Comparative Example 1 Raw material atmospheric residue 0.25 - Experimental Example 1 Purification of atmospheric residue 1.75 18.57 Experimental Example 2 Purification of atmospheric residue 4.25 26.32 Experimental Example 3 Purification of atmospheric residue 6 hours without blockage 34.15

[0089] The atmospheric residue oil was heated to 365° C. Experimental Examples 1, 2, and 3 in Table 1 were tested using purified oil taken when the equipment was running for 0.5 h.

[0090] The data in Table 1 show that, based on a comparison of the clogging durations of the purified atmospheric residue filtration tests in Examples 1-3 with the clogging durations of the raw atmospheric residue filtration test in Comparative Example 1, the filtration test durations of the purified atmospheric residue were significantly increased after treatment with the anti-coking device. Furthermore, the filtration test run time was even longer when the electric field strength was higher and the residence time was longer, indicating that the insoluble matter content of the purified atmospheric residue in the subsequent separation system was significantly reduced, significantly reducing its coking tendency. After treatment with the anti-coking device, the n-heptane insoluble matter content in the impurities increased with increasing electric field strength and residence time, and the non-asphalt components entrained in the impurities were reduced, reducing oil product losses.

[0091] Comparative Example 2

[0092] A method for preventing coking in a residual oil hydrogenation product separation process in an ebullated bed comprises the following steps:

[0093] (1) Test using anti-coking device C;

[0094] (2) The atmospheric residue oil is heated to 365°C and transported to an anti-coking device for treatment. The electric field applied by the device is a DC electric field with an electric field strength of 15,000 V / cm. The residence time of the purified reaction product in the anti-coking device is 2 hours;

[0095] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0096] (4) Use toluene solvent to extract the impurities and analyze the content of toluene insoluble matter in the impurities.

[0097] Comparative Example 3

[0098] A coking prevention treatment process for separating products from ebullated bed residue oil hydrogenation products comprises the following steps:

[0099] (1) Test using anti-coking device D;

[0100] (2) The atmospheric residue oil is heated to 365°C and transported to an anti-coking device for treatment. The electric field applied by the device is a DC electric field with an electric field strength of 15,000 V / cm. The residence time of the purified reaction product in the anti-coking device is 2 hours;

[0101] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0102] (4) Use toluene solvent to extract the impurities and analyze the content of toluene insoluble matter in the impurities.

[0103] Comparative Example 4

[0104] A coking prevention treatment process for separating products from ebullated bed residue oil hydrogenation products comprises the following steps:

[0105] (1) Test using the anti-coking device E;

[0106] (2) The atmospheric residue oil is heated to 365°C and transported to an anti-coking device for treatment. The electric field applied by the device is a DC electric field with an electric field strength of 15,000 V / cm. The residence time of the purified reaction product in the anti-coking device is 2 hours;

[0107] (3) The purified reaction product is obtained in the upper part of the anti-coking device, and impurities are discharged in the lower part. The purified reaction product is filtered at 365°C using a filter with a pore size of 5 μm, and the time taken for the pressure in the filtration system to rise to 0.8 MPa is recorded;

[0108] (4) Use toluene solvent to extract the impurities and analyze the content of toluene insoluble matter in the impurities.

[0109] Table 2 Effect of structural changes of anti-coking devices with different structures

[0110]

[0111]

[0112] Backwash was not used during the above experiments;

[0113] It can be seen from the data in Table 2 that: the toluene insoluble matter content in the purified atmospheric residue (Example 1) of the electric field purified oil (Example 3, Comparative Examples 2-4) is reduced to a minimum of 0.05%, and the duration of filter clogging is significantly increased. When the anti-coking device designs the lower sedimentation separation tank (Example 3, Comparative Example 3), the overall current of the device is relatively small, and the device energy consumption is low; when the anti-coking device does not adopt the lower sedimentation separation tank (Comparative Example 2, Comparative Example 4), the overall current of the device is significantly increased, and the device energy consumption is high. This is because the impurity components contain more polar components. When the device does not have a lower sedimentation separation area, the impurities are closer to the electric field area, and the electric field effect is strong, which can increase the current in the electric field area. When the lower electrode plate of the anti-coking device is designed to be inclined (Example 3, Comparative Example 4), the impurities precipitated under the action of the electric field can be deposited downward along the lower electrode plate, and less is deposited on the lower electrode plate. As the operating time of the device increases, the quality of the purified oil (judged by the toluene insoluble matter content and the filter clogging time of the filtration test) decreases relatively slowly; when the lower electrode plate of the anti-coking device is designed to be horizontal (Comparative Example 2, Comparative Example 3), the impurities precipitated under the action of the electric field will be more deposited on the lower electrode plate. As the operating time of the device increases, the impurities accumulated on the lower electrode plate increase, which will partially shield the electric field and affect the purification effect of the electric field, which is manifested as an increase in the toluene insoluble matter content in the purified oil and a large decrease in the current of the device (impurities accumulate on the lower electrode plate, causing the effective voltage between the plates to decrease, thereby reducing the current).

Claims

1. A coking prevention device for residual oil hydrogenation in an ebullated bed, comprising an electrostatic separation zone (1) having an upper electrode plate (2) and a lower electrode plate (3) arranged opposite to each other, wherein the upper electrode plate (2) is charged, thereby forming an electric field zone (102) between the upper and lower electrode plates, wherein residual oil enters the electric field zone (102), and light oil purified by the electric field is discharged through the top of the electrostatic separation zone (1), characterized in that: The upper electrode plate (2) and the lower electrode plate (3) separate the electrostatic separation area (1) into an upper light oil discharge area (101), a middle electric field area (102), and a lower heavy oil area (103). Through holes for light oil to pass through are distributed on the surface of the upper electrode plate (2); heavy oil channels (301) penetrating the heavy oil area (103) are distributed on the lower electrode plate (3); A sedimentation separation zone (6) is provided below the electrostatic separation zone (1), and the heavy oil zone (103) is connected to the bottom of the sedimentation separation zone (6) via a heavy component delivery pipe (104), so that the heavy oil in the heavy oil zone (103) is introduced into the sedimentation separation zone (6), and an impurity oil discharge port (601) is provided at the bottom of the sedimentation separation zone (6); The top of the sedimentation separation zone (6) is provided with a liquid suction pipe (701), the liquid suction pipe (701) is connected to the liquid inlet of the backwash pump (7), the liquid outlet of the backwash pump (7) is provided with a backwash pipe (702), and the end of the backwash pipe (702) extends to a position on the upper surface of the lower electrode plate (3) opposite to the heavy oil channel (301); The sedimentation and separation zone (6) includes a closed tank body, and the tank body is divided into a sedimentation zone (602), a transition zone (603) and a light oil zone (604) from bottom to top, wherein the height of the sedimentation zone (602) accounts for 60-80% of the sedimentation and separation zone (6), and the width of the transition zone (603) gradually increases from bottom to top, with the bottom flush with the sedimentation zone (602) and the top flush with the light oil zone (604).

2. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: There is a gap between the edges of the upper electrode plate (2) and the lower electrode plate (3) and the inner side wall of the electrostatic separation area (1), forming an edge channel.

3. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: An insulating layer I (106) is filled between the edges of the upper electrode plate (2) and the lower electrode plate (3) and the inner side wall of the electrostatic separation area (1).

4. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: The upper surface of the upper electrode plate (2) is covered with an insulating layer II (204) to prevent an electric field from being formed in the light oil discharge area (101).

5. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: The upper electrode plate (2) is connected to the top of the electrostatic separation zone (1) via a suspension rod (201), and the top end of the suspension rod (201) extends out of the electrostatic separation zone (1) and is connected to the high-voltage power supply device (5), and the top end of the suspension rod (201) is sealed by an insulating cover (203).

6. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: The lower electrode plate (3) is arranged to be inclined from one side to the other side, and the heavy oil channel (301) is located on the side at a lower position.

7. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: The bottom of the lower electrode plate (3) is supported by a plurality of supporting legs (302), so that the lower electrode plate (3) forms an inclined surface.

8. The anti-coking device for ebullated bed residue oil hydrogenation according to claim 1, characterized in that: The temperature difference between the electrostatic separation zone (1) and the sedimentation separation zone (6) and the temperature of the residual oil when entering the electric field zone (102) is controlled to be 5-10°C.

9. A system for separating products from residual oil hydrogenation in an ebullated bed, characterized by: The product (A) of the residual oil hydrogenation reaction in the ebullated bed is first passed into the hot high-pressure separator (801) to separate hydrogen and reaction oil gas. The hot oil gas is cooled by heat exchange and then enters the cold high-pressure separator (802) to further separate oil gas and hydrogen. The separated hydrogen enters the circulating hydrogen desulfurization device (805) for desulfurization and then participates in the hydrogenation reaction again as circulating hydrogen (B); the oil phase separated at the bottom of the hot high-pressure separator (801) enters the hot low-pressure separator (803). The gas phase separated by the high-pressure separator (803) is mixed with the oil phase at the bottom of the cold high-pressure separator (802) and enters the cold low-pressure separator (804). The cold low-pressure separator (804) separates the acid gas (C) and removes it to the acid gas treatment device. The oil phase at the bottom is mixed with the oil phase separated by the hot low-pressure separator (803) and sent to the atmospheric distillation tower (807). Dry gas (D), naphtha (E) and diesel (F) are fractionated. The atmospheric residue oil produced enters the vacuum distillation tower. (808), the vacuum wax oil (G) and the unconverted oil (H) at the bottom of the tower are separated; the atmospheric residue oil produced by the atmospheric distillation tower (807) is first passed into the anti-coking device (806) described in any one of claims 1-7 for treatment, and the impurity component (I) is separated, and the light oil produced is then sent to the vacuum distillation tower (808); or, the oil phase at the bottom of the cold low-pressure separator (804) is mixed with the oil phase separated by the hot low-pressure separator (803), and then first passed into the anti-coking device (806) described in any one of claims 1-7 for treatment, and the impurity component (I) is separated, and the light oil produced is then sent to the atmospheric distillation tower (807); or, the oil phase separated at the bottom of the hot high-pressure separator (801) is first passed into the anti-coking device (806) described in any one of claims 1-7 for treatment, and the impurity component (I) is separated, and the light oil produced is then sent to the hot low-pressure separator (803).

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