An on-line hot coke draining system and method for a fluidized bed reactor

Abstract

The application discloses a kind of boiling bed reactor online hot state coke discharging system and method, including coke residue transfer pipeline, coke residue transfer valve, coke residue transfer tank, pressure balance pipeline, pressure balance valve, coke residue discharge pipeline, coke residue discharge valve, cooler;The upper inlet end of the coke residue transfer tank is connected with the outlet end of the bottom of boiling bed reactor by coke residue transfer pipeline, and coke residue transfer valve is arranged on the coke residue transfer pipeline, and the outlet end of the top of coke residue transfer tank is provided with pressure balance pipeline, and pressure balance valve is arranged on the pressure balance pipeline, and the upper gas inlet end of hot high-pressure separator is connected with the pressure balance pipeline, and coke residue discharge pipeline is arranged on the lower end of the bottom of coke residue transfer tank, and coke residue discharge valve and cooler are arranged on the coke residue discharge pipeline.The application completes the online hot state coke discharging under normal operation condition of device, realizes the safe and stable long full operation of device, and does not affect original process condition and conversion effect.

Description

Technical Field

[0001] This invention relates to the field of fluidized bed hydrogenation reaction technology, specifically to an online hot coke removal system and method for a fluidized bed reactor. Background Technology

[0002] Fluidized bed hydrotreating technology is favored in the hydrogenation of heavy and low-quality oils and direct coal-to-oil processes due to its strong adaptability to feedstocks. However, because it involves high-temperature and high-pressure reactions, coking is inevitable. Most of the coke generated is carried out of the reactor by the high-speed flow of reactants, but a small portion remains inside. This coke gradually accumulates and eventually clogs the reactor, affecting the long-term stable operation of the unit. To address this issue, some methods use forced circulation pumps or internal circulation to alleviate solid deposition. While these methods can enhance material flow within the reactor and reduce solid deposition, they also increase the complexity of the reactor's internal structure and do not solve the problem of coke discharge; the coke continues to accumulate within the system. Other methods reduce coking by lowering the reaction temperature, but this significantly reduces the single-pass conversion rate, requiring extensive recirculation to improve the overall conversion rate. This also significantly increases the investment and operating costs per unit processing volume, severely impacting the economic viability of the unit. Currently, fluidized bed reactors, both domestically and internationally, cannot perform coke removal operations without shutting down. How to solve the problem of online hot coke removal in fluidized bed hydrogenation reactors has become a technical challenge in this field.

[0003] Chinese patent CN202020539165.7 discloses a circulating fluidized bed return material anti-clogging hot slag discharge structure, including a gasifier, a cyclone separator, an upper return material unit, a pyrolysis furnace, and a lower return material unit. A discharge port is provided at the bottom of the lower return material unit, which is connected to the inlet of a water-cooled screw conveyor via a high-temperature slag discharge pipe. The outlet of the water-cooled screw conveyor discharges coke lumps through the slag discharge pipe, which is connected to a nitrogen pipeline. A discharge valve is provided at the bottom of the slag discharge pipe. The beneficial effect of this invention is that large-volume coke lumps that cannot participate in the circulation and accumulate in the lower return material unit can enter the water-cooled screw conveyor through the high-temperature slag discharge pipe at the bottom of the lower return material unit, cool down, and then be discharged through the slag discharge pipe. Simultaneously, nitrogen gas will seal the gas in the slag discharge pipe to prevent gas leakage. However, this method is not suitable for high-temperature and high-pressure reaction systems.

[0004] Chinese patent CN201810531710.5 discloses an online slag discharge device and method for a fluidized bed reactor in a polycrystalline silicon cold hydrogenation reaction system. The device includes a slag receiving tank, a slag discharge pipeline between the fluidized bed reactor and the receiving tank, and a first valve on the discharge pipeline for controlling the discharge from the fluidized bed reactor. The online slag discharge device also includes an inlet pipeline for introducing gas, which is connected to the discharge pipeline. The connection point between the inlet pipeline and the discharge pipeline is located downstream of the first valve. This method discharges deactivated material from the fluidized bed reactor without shutting down, increasing the proportion of effective reactants and improving the reaction conversion rate. However, this method is not applicable to high-temperature, high-pressure reaction systems, and the gas return from the slag receiving tank to the reactor results in relatively high back pressure and low slag discharge power, which can easily lead to poor slag discharge or even blockage. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide an online hot coke discharge system and method for a fluidized bed reactor. Without shutting down the unit, coke residue in the fluidized bed reactor is first transferred to a coke residue transfer tank, then the coke residue transfer tank is disconnected from the reaction system, and finally, the coke residue is discharged externally from the transfer tank. This allows for online hot coke discharge under normal operating conditions, achieving stable, long-term, and high-efficiency operation of the unit without affecting the original process conditions and conversion efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An online hot coke discharge system for a fluidized bed reactor includes a coke slag transfer pipeline 4, a coke slag transfer valve, a coke slag transfer tank 2, a pressure balancing pipeline 5, a pressure balancing valve, a coke slag discharge pipeline 6, a coke slag discharge valve 11, and a cooler 12.

[0008] The upper inlet end of the coke slag transfer tank 2 is connected to the bottom outlet end of the fluidized bed reactor 1 via a coke slag transfer pipeline 4. A coke slag transfer valve is installed on the coke slag transfer pipeline 4. A pressure balancing pipeline 5 is installed at the top outlet end of the coke slag transfer tank 2. A pressure balancing valve is installed on the pressure balancing pipeline 5. The pressure balancing pipeline 5 is connected to the upper air inlet end of the hot high-pressure separator 3. A coke slag discharge pipeline 6 is installed at the bottom of the lower end of the coke slag transfer tank 2. A coke slag discharge valve 11 and a cooler 12 are installed on the coke slag discharge pipeline 6.

[0009] The coke slag transfer pipeline 4 is equipped with a primary coke slag transfer valve 7 and a secondary coke slag transfer valve 8. The primary coke slag transfer valve 7 is used to isolate the fluidized bed reactor 1 and the coke slag transfer tank 2 after the coke slag is transferred to the coke slag transfer tank, and to prevent hydrogen from entering the coke slag transfer tank 2 during the coke discharge process of the coke transfer tank, while ensuring that nitrogen enters the coke slag transfer tank 2. The secondary coke slag transfer valve 8 is used to isolate the fluidized bed reactor 1 and the coke slag transfer tank 2 after the coke slag is transferred to the coke slag transfer tank.

[0010] The primary coke slag transfer valve 7 is located close to the bottom of the fluidized bed reactor 1. A coke slag transfer hydrogen injection pipeline is installed before the primary coke slag transfer valve 7. The coke slag transfer hydrogen injection pipeline is located close to the primary coke slag transfer valve 7 and is connected to the coke slag transfer pipeline 4. A coke slag transfer pipeline hydrogen injection valve 13 is installed on the coke slag transfer hydrogen injection pipeline. A nitrogen pipeline is also installed after the primary coke slag transfer valve 7. The nitrogen pipeline is located before the secondary coke slag transfer valve 8 and is located close to the primary coke slag transfer valve 7. The nitrogen pipeline is connected to the coke slag transfer pipeline 4 and is equipped with a nitrogen valve 14.

[0011] The pressure balancing pipeline 5 is equipped with a primary pressure balancing valve 9 and a secondary pressure balancing valve 10. The primary pressure balancing valve 9 is used to prevent gas from the top of the coke slag transfer tank 2 from entering the pressure balancing pipeline 5 when the coke slag transfer tank 2 discharges coke slag. The secondary pressure balancing valve 10 is used to prevent oil and gas in the hot high-pressure separator 3 from entering the pressure balancing pipeline 5 when the coke slag transfer tank 2 discharges coke slag. The pressure balancing pipeline 5 is connected to the air inlet at the top of the hot high-pressure separator 3. The primary pressure balancing valve 9 is set close to the coke slag transfer tank 2, and the secondary pressure balancing valve 10 is set close to the hot high-pressure separator 3.

[0012] The coke slag discharge valve 11 is located close to the bottom of the coke slag transfer tank 2. A hydrogen injection pipeline for the coke slag transfer tank 2 is installed in front of the coke slag discharge valve 11. The hydrogen injection pipeline is used to inject hydrogen into the coke slag transfer tank 2 to prevent coking inside the coke slag transfer tank 2. The hydrogen injection pipeline for the coke slag transfer tank 2 is located close to the coke slag discharge valve 11. The gas inlet end of the hydrogen injection pipeline is connected to the gas inlet end of the coke slag discharge pipeline 6. A coke slag transfer tank hydrogen injection valve 15 is installed on the hydrogen injection pipeline.

[0013] A coke removal method for an online hot coke removal system in a fluidized bed reactor includes the following steps:

[0014] 1) Open the primary coke slag transfer valve 7 and the secondary coke slag transfer valve 8, and the coke slag at the bottom of the fluidized bed reactor 1 is transferred to the coke slag transfer tank 2 through the coke slag transfer pipeline 4;

[0015] 2) Slowly open the primary pressure balancing valve 9 and the secondary pressure balancing valve 10 to maintain pressure balance between the coke slag transfer tank 2 and the hot high-pressure separator 3. The coke slag at the bottom of the fluidized bed reactor 1 continues to be transferred to the coke slag transfer tank 2 through the coke slag transfer pipeline 4.

[0016] 3) Open the hydrogen injection valve 15 of the coke slag transfer tank and inject hydrogen into the coke slag transfer tank 2 to prevent coke slag from depositing and adhering in the coke slag transfer tank 2;

[0017] 4) After the coke slag transfer is completed, close the primary coke slag transfer valve 7, open the hydrogen injection valve 13 of the coke slag transfer pipeline, inject hydrogen into the fluidized bed reactor 1 through the coke slag transfer pipeline 4, close the primary pressure balance valve 9 and the secondary pressure balance valve 10, close the hydrogen injection valve 15 of the coke slag transfer tank, open the coke slag discharge valve 11, and the coke slag in the coke slag transfer tank 2 is cooled and discharged through the coke slag discharge pipeline 6 to the cooler 12.

[0018] 5) Open the nitrogen valve 14 after the primary coke slag transfer valve 7, inject nitrogen into the coke slag transfer tank 2 through the coke slag transfer pipeline 4, and discharge it through the coke slag discharge pipeline 6 and the cooler 12 to purge and replace the system. After the system is purged, close the nitrogen valve 14 and the secondary coke slag transfer valve 8, and close the coke slag discharge valve 11 and the cooler 12.

[0019] The average temperature of the fluidized bed reactor 1 is 420℃~472℃ and the pressure is 10MPa~23MPa. The average temperature of the hot high-pressure separator 3 is 420℃~472℃ and the pressure is 10MPa~23MPa.

[0020] This invention is applicable to, but not limited to, fluidized bed hydrogenation of wax oil, fluidized bed hydrogenation of heavy and inferior oil, kerosene co-refining, and direct coal liquefaction.

[0021] The beneficial effects of this invention are:

[0022] The present invention employs an online hot coke removal system and method for a fluidized bed hydrogenation reactor. Under normal operation of the fluidized bed hydrogenation unit, the coke residue is transferred and discharged, which can reduce the accumulation and deposition of coke residue in the fluidized bed reactor, effectively slow down coking in the fluidized bed reactor, and extend the operating cycle of the fluidized bed hydrogenation unit. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an online hot coke removal system for a fluidized bed hydrogenation reactor according to the present invention.

[0024] Wherein: 1-fluidized bed reactor; 2-coke residue transfer tank; 3-hot high-pressure separator; 4-coke residue transfer pipeline; 5-pressure balancing pipeline; 6-coke residue discharge pipeline; 7-primary coke residue transfer valve; 8-secondary coke residue transfer valve; 9-primary pressure balancing valve; 10-secondary pressure balancing valve; 11-coke residue discharge valve; 12-cooler; 13-hydrogen injection valve for coke residue transfer pipeline; 14-nitrogen valve; 15-hydrogen injection valve for coke residue transfer tank. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] Example 1:

[0027] The kerosene co-refining unit has an average temperature of 470℃ and a pressure of 21.3MPa in the fluidized bed reactor 1, and an average temperature of 470℃ and a pressure of 20.5MPa in the hot high-pressure separator 3. The catalyst used is a solid powder catalyst.

[0028] like Figure 1 As shown: Under normal operation, the unit performs an online hot coke removal operation once a month. The coke removal steps are as follows:

[0029] 1) Open the primary coke slag transfer valve 7 and the secondary coke slag transfer valve 8, and the coke slag at the bottom of the fluidized bed reactor 1 is transferred to the coke slag transfer tank 2 through the coke slag transfer pipeline 4;

[0030] 2) Slowly open the primary pressure balancing valve 9 and the secondary pressure balancing valve 10 to maintain pressure balance between the coke slag transfer tank 2 and the hot high-pressure separator 3. The coke slag at the bottom of the fluidized bed reactor 1 continues to be transferred into the coke slag transfer tank 2 through the coke slag transfer pipeline 4.

[0031] 3) Open the hydrogen injection valve 15 of the coke slag transfer tank and inject hydrogen gas at a pressure of 21.5MPa into the coke slag transfer tank to prevent coke slag from depositing and adhering in the coke slag transfer tank 2;

[0032] 4) After the coke slag transfer is completed, close the primary coke slag transfer valve 7, open the hydrogen injection valve 13 of the coke slag transfer pipeline, and inject hydrogen gas at a pressure of 21.5 MPa into the fluidized bed reactor 1 through the coke slag transfer pipeline 4. Then, close the primary pressure balance valve 10 and the secondary pressure balance valve 9 in sequence, close the hydrogen injection valve 13 of the coke slag transfer tank, and open the coke slag discharge valve 11. The coke slag in the coke slag transfer tank 2 goes to the cooler 12 through the coke slag discharge pipeline 6 and is discharged after cooling.

[0033] 5) Open the nitrogen valve 14 and inject nitrogen at a pressure of 1MPa into the coke slag transfer tank 2 through the coke slag transfer pipeline 4. Then, vent the nitrogen through the coke slag discharge pipeline 6 and the cooler 12 to purge and replace the system. After the system is purged, close the nitrogen valve 14 and the secondary coke slag transfer valve 8, and close the coke slag discharge valve 11 and the cooler 12.

[0034] Example 2:

[0035] Heavy and low-quality oil fluidized bed hydrocracking unit;

[0036] The average temperature of the fluidized bed reactor 1 is 460℃ and the pressure is 18.3MPa. The average temperature of the hot high-pressure separator 3 is 460℃ and the pressure is 17.5MPa. The catalyst used is a solid powder catalyst.

[0037] Under normal operating conditions, an online hot coke removal operation is performed every two months. The coke removal steps are as follows:

[0038] 1) Open the primary coke slag transfer valve 7 and the secondary coke slag transfer valve 8, and the coke slag at the bottom of the fluidized bed reactor 1 enters the coke slag transfer tank 2 through the coke slag transfer pipeline 4;

[0039] 2) Slowly open the primary pressure balancing valve 9 and the secondary pressure balancing valve 10 to maintain pressure balance between the coke slag transfer tank 2 and the hot high-pressure separator 3. The coke slag at the bottom of the fluidized bed reactor 1 continues to enter the coke slag transfer tank 2 through the coke slag transfer pipeline 4.

[0040] 3) Open the hydrogen injection valve 15 of the coke slag transfer tank and inject hydrogen gas at a pressure of 18.5 MPa into the coke slag transfer tank to prevent coke slag from depositing and adhering in the coke slag transfer tank 2;

[0041] 4) After the coke residue transfer is completed, close the primary coke residue transfer valve 7, open the hydrogen injection valve 13 of the coke residue transfer pipeline, and inject hydrogen gas at a pressure of 18.5 MPa into the fluidized bed reactor 1 through the coke residue transfer pipeline 4. Then, close the primary pressure balance valve 10 and the secondary pressure balance valve 9 in sequence, close the hydrogen injection valve 13 of the coke residue transfer tank, and open the coke residue discharge valve 11. The coke residue in the coke residue transfer tank 2 goes to the cooler 12 through the coke residue discharge pipeline 6 and is discharged after cooling.

[0042] 5) Open the nitrogen valve 14 and inject nitrogen at a pressure of 1MPa into the coke slag transfer tank 2 through the coke slag transfer pipeline 4. Then, vent the nitrogen through the coke slag discharge pipeline 6 and the cooler 12 to purge and replace the system. After the system is purged, close the nitrogen valve 14 and the secondary coke slag transfer valve 8, and close the coke slag discharge valve 11 and the cooler 12.

Claims

1. An online hot coke removal system for a fluidized bed reactor, characterized in that, Includes coke slag transfer pipeline (4), coke slag transfer valve, coke slag transfer tank (2), pressure balancing pipeline (5), pressure balancing valve, coke slag discharge pipeline (6), coke slag discharge valve (11), and cooler (12). The upper inlet end of the coke slag transfer tank (2) is connected to the bottom outlet end of the fluidized bed reactor (1) through the coke slag transfer pipeline (4). A coke slag transfer valve is installed on the coke slag transfer pipeline (4). A pressure balance pipeline (5) is installed at the top outlet end of the coke slag transfer tank (2). A pressure balance valve is installed on the pressure balance pipeline (5). The pressure balance pipeline (5) is connected to the upper air inlet end of the hot high pressure separator (3). A coke slag discharge pipeline (6) is installed at the bottom of the lower end of the coke slag transfer tank (2). A coke slag discharge valve (11) and a cooler (12) are installed on the coke slag discharge pipeline (6). The coke slag transfer pipeline (4) is equipped with a primary coke slag transfer valve (7) and a secondary coke slag transfer valve (8). The primary coke slag transfer valve (7) is used to isolate the fluidized bed reactor (1) and the coke slag transfer tank (2) after the coke slag is transferred to the coke slag transfer tank, and to prevent hydrogen from entering the coke slag transfer tank (2) during the coke discharge process of the coke transfer tank, and to ensure that nitrogen enters the coke slag transfer tank (2). The secondary coke slag transfer valve (8) is used to isolate the fluidized bed reactor (1) and the coke slag transfer tank (2) after the coke slag is transferred to the coke slag transfer tank. The average temperature of the fluidized bed reactor (1) is 420℃~472℃ and the pressure is 10MPa~23MPa. The average temperature of the hot high pressure separator (3) is 420℃~472℃ and the pressure is 10MPa~23MPa.

2. The online hot coke removal system for a fluidized bed reactor according to claim 1, characterized in that, The primary coke slag transfer valve (7) is located close to the bottom of the fluidized bed reactor (1). A coke slag transfer hydrogen injection pipeline is installed before the primary coke slag transfer valve (7). The coke slag transfer hydrogen injection pipeline is located close to the primary coke slag transfer valve (7). The coke slag transfer hydrogen injection pipeline is connected to the coke slag transfer pipeline (4). A coke slag transfer pipeline hydrogen injection valve (13) is installed on the coke slag transfer hydrogen injection pipeline. A nitrogen pipeline is also installed after the primary coke slag transfer valve (7). The nitrogen pipeline is located before the secondary coke slag transfer valve (8) and close to the primary coke slag transfer valve (7). The nitrogen pipeline is connected to the coke slag transfer pipeline (4). A nitrogen valve (14) is installed on the nitrogen pipeline.

3. The online hot coke removal system for a fluidized bed reactor according to claim 1, characterized in that, The pressure balancing pipeline (5) is equipped with a primary pressure balancing valve (9) and a secondary pressure balancing valve (10). The primary pressure balancing valve (9) is used to prevent gas from the top of the coke slag transfer tank (2) from entering the pressure balancing pipeline (5) when the coke slag transfer tank (2) discharges coke slag. The secondary pressure balancing valve (10) is used to prevent oil and gas in the hot high pressure separator (3) from entering the pressure balancing pipeline (5) when the coke slag transfer tank (2) discharges coke slag. The pressure balancing pipeline (5) is connected to the air inlet at the top of the hot high pressure separator (3). The primary pressure balancing valve (9) is set close to the coke slag transfer tank (2), and the secondary pressure balancing valve (10) is set close to the hot high pressure separator (3).

4. The online hot coke removal system for a fluidized bed reactor according to claim 1, characterized in that, The coke slag discharge valve (11) is located close to the bottom of the coke slag transfer tank (2). A hydrogen injection pipeline for the coke slag transfer tank (2) is installed in front of the coke slag discharge valve (11). The hydrogen injection pipeline is used to inject hydrogen into the coke slag transfer tank (2) to prevent coking inside the coke slag transfer tank (2). The hydrogen injection pipeline for the coke slag transfer tank (2) is located close to the coke slag discharge valve (11). The gas inlet end of the hydrogen injection pipeline is connected to the gas inlet end of the coke slag discharge pipeline (6). A coke slag transfer tank hydrogen injection valve (15) is installed on the hydrogen injection pipeline.

5. An online hot coke removal system for a fluidized bed reactor according to any one of claims 1-4, characterized in that, The coke discharge system is applicable to, but not limited to, wax oil fluidized bed hydrogenation, heavy and inferior oil fluidized bed hydrogenation, kerosene co-refining, and direct coal liquefaction.

6. A coke removal method based on the online hot coke removal system of a fluidized bed reactor according to any one of claims 1-4, characterized in that, Includes the following steps: 1) Open the primary coke slag transfer valve (7) and the secondary coke slag transfer valve (8), and the coke slag at the bottom of the fluidized bed reactor (1) is transferred to the coke slag transfer tank (2) through the coke slag transfer pipeline (4). 2) Slowly open the first-stage pressure balancing valve (9) and the second-stage pressure balancing valve (10) to keep the pressure of the coke slag transfer tank (2) and the hot high-pressure separator (3) balanced. The coke slag at the bottom of the fluidized bed reactor (1) continues to be transferred to the coke slag transfer tank (2) through the coke slag transfer pipeline (4). 3) Open the hydrogen injection valve (15) of the coke slag transfer tank and inject hydrogen into the coke slag transfer tank (2) to prevent coke slag from depositing and adhering in the coke slag transfer tank (2); 4) After the coke slag transfer is completed, close the first-stage coke slag transfer valve (7), open the hydrogen injection valve (13) of the coke slag transfer pipeline, inject hydrogen into the fluidized bed reactor (1) through the coke slag transfer pipeline (4), close the first-stage pressure balance valve (9) and the second-stage pressure balance valve (10), close the hydrogen injection valve (15) of the coke slag transfer tank, open the coke slag discharge valve (11), and the coke slag in the coke slag transfer tank (2) is cooled and discharged through the coke slag discharge pipeline (6) to the cooler (12); 5) Open the nitrogen valve (14) after the primary coke slag transfer valve (7), inject nitrogen into the coke slag transfer tank (2) through the coke slag transfer pipeline (4), and discharge it through the coke slag discharge pipeline (6) and cooler (12) to purge and replace the system. After the system is purged, close the nitrogen valve (14) and the secondary coke slag transfer valve (8), and close the coke slag discharge valve (11) and cooler (12).

7. The coke removal method of an online hot coke removal system for a fluidized bed reactor according to claim 6, characterized in that, The average temperature of the fluidized bed reactor (1) is 420℃~472℃ and the pressure is 10MPa~23MPa. The average temperature of the hot high pressure separator (3) is 420℃~472℃ and the pressure is 10MPa~23MPa.

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