Circulating pump and driving system thereof

Abstract

The invention discloses a circulating pump and a driving system thereof. The driving system of the circulating pump comprises a water turbine, a main shield pump, an oil container and an oil pipe. An oil path inlet of the main shield pump is communicated with the oil container through an oil pipe; an oil way outlet of the main shield pump is communicated with an oil way inlet of the water turbine through an oil pipe; an oil way outlet of the water turbine is communicated with the oil container through an oil pipe; and a main shaft of the water turbine is coaxially connected with a pump shaft of the circulating pump. The circulating pump is suitable for the fields of petrochemical industry and coal chemical industry, especially for a hydrocracking fluidized bed reactor and an oil slurry reactor, compared with the prior art, the circulating pump has the advantages that the total cost is greatly reduced, the energy-saving and consumption-reducing benefits are remarkable, and meanwhile, the reliability of the system is effectively improved.

Description

Technical Field

[0001] The invention relates to equipment for petrochemical industry and coal chemical industry, and in particular to a circulation pump and a driving system thereof. Background Art

[0002] The circulating pump (also called boiling pump) is one of the core equipment of hydrocracking fluidized bed technology. It was developed by ByronJackson in the United States in parallel with the hydrocracking fluidized bed reactor since the 1960s. Its design adapts to the complex working conditions of high temperature (generally 400-500°C), high pressure (generally 11-21MPa), hydrogen, heavy oil asphaltene and catalyst particles in the hydrocracking fluidized bed reactor. Through the integrated wet motor design, it solves the leakage risk of traditional mechanical seals and meets the process requirements of catalyst bed expansion and material backmixing in the reactor. In recent years, a domestic company has also developed this type of circulating pump, and the principle is roughly the same as the former.

[0003] Due to the superiority of hydrocracking ebullated bed reactor technology in the processing of heavy oil and solid-containing oil products, Byron Jackson's wet motor driven circulating pump technology has solved the extreme operating conditions challenges of the hydrocracking ebullated bed reactor, becoming a key equipment in the field of heavy oil processing and coal chemical industry, and has been widely used in residue oil hydrogenation and coal direct liquefaction technology.

[0004] Nevertheless, the above circulation pumps still have technical limitations and problems in practical applications, including: 1. High initial investment, operating costs and maintenance costs (1.1) Expensive materials and manufacturing processes: The special insulation materials of wet motors make the equipment cost significantly higher than that of traditional motors; (1.2) Extremely high energy consumption: This type of wet motor requires an operating voltage of up to 2400V. In order to prevent the insulation layer of the coil that drives the rotor from being broken down, the thickness of the insulation layer needs to be much greater than that of the insulation layer of an ordinary motor. Therefore, for the same output power, the amount of coils required to be wound in a wet motor is several times that of a conventional motor, which not only makes the motor bulky, but also seriously reduces the efficiency of the motor. The reality is that its energy consumption is about 6 times that of existing conventional motors. For example, if a wet motor runs 8760 hours a year, the motor power is 300KW, and the power consumption is 2628000 degrees / year (the power of a conventional motor is 50KW and the power consumption is 438000 degrees / year). With such a high operating voltage, the cost of the entire power supply system is also very high. In order to prevent the sedimentation of materials in the reactor from causing coking or local overheating, a part of the lubricating medium needs to flow into the reactor through the pump shaft and the bearing. The ideal medium is diesel, so the medium for the cooling coil is required to be diesel. Since the coil is in contact with the diesel, the insulation performance of the diesel is required. For this reason, the diesel needs to be dehydrated and impurities removed. Each production unit requires several thousand tons of processed diesel every year, which undoubtedly greatly increases the investment in equipment and processing costs.

[0005] (1.3) There are many accessories: When the wet motor is running, its own coil will heat up, and the temperature of the medium that the impeller contacts is about 540℃. The heat on the impeller will also be transferred to the pump shaft. The heat on the bearing will heat the oil inside the wet motor used for sealing, lubrication and flushing. Due to the allowable temperature limit of the motor coil, the oil in the motor needs to flow in and out continuously. Therefore, a heat exchanger needs to be configured separately, which requires a series of corresponding supporting measures and equipment instruments such as piping, insulation, and antifreeze, as well as consideration of instrument redundancy.

[0006] (1.4) High design and installation complexity 2. Multiple risks and factors affect system reliability (2.1) Many risks: First, this type of motor has temperature rise requirements and needs to rely on cooling medium. Therefore, the cooling medium of the motor, that is, the injection amount of lubricating oil, needs to be dynamically adjusted according to the operating conditions to ensure the safe operation of the motor; second, the insulation layer of the motor coil will be thinned or damaged by the cooling medium, resulting in leakage risk, which may cause production suspension; if the motor is damaged, it must be stopped and replaced, which will affect the reliability of the system (there are precedents in the industry) (2.2) Backup pump configuration: Due to the high price, backup pumps are usually not installed. If a backup pump is configured, the purchase and operation costs will undoubtedly be further increased: In order to prevent coking inside the backup pump, the backup pump must be running at all times. Even when running at the lowest speed, it is still necessary to pass lubricating and cooling oil to cool the motor. Low-speed operation and the circulation of lubricating and cooling oil consume electricity. Part of the oil will flow into the reactor, wasting the lubricating and cooling oil that has been treated by dehydration and impurity removal.

[0007] In order to solve the above problems, the industry has been studying alternative solutions; for example, someone has come up with the idea of ​​using hydrogen circulation to drive the mixing of materials in the reactor and control the expansion of the catalyst bed, but this process is not only energy-intensive; and because hydrogen has a very small specific gravity and small momentum per unit volume, its ability to flow and drive other media in the reactor is restricted. Therefore, its process effect is not ideal, and it will produce coke in a shorter production cycle, which affects production efficiency and increases the labor intensity of workers. It has not been widely promoted so far. Summary of the invention

[0008] In view of the technical problems existing in the prior art, the present invention aims to provide a circulating pump which is efficient, energy-saving, reliable in use and easy to maintain, and is particularly suitable for use in hydrocracking fluidized bed reactors and coal chemical reactors.

[0009] The technical solution of the present invention is achieved in this way: A circulating pump driving system comprises a water turbine, a main canned pump, an oil container and an oil pipe; the oil inlet of the main canned pump is connected to the oil container through the oil pipe; The oil circuit outlet of the main canned motor pump is connected to the oil circuit inlet of the turbine through an oil pipe; The oil outlet of the turbine is connected to the oil container through an oil pipe; The main shaft of the water turbine is coaxially connected to the pump shaft of the circulating pump.

[0010] Taking into account the need for maintenance, a three-valve group can also be installed on the oil pipe between the turbine and the main shielded pump.

[0011] Furthermore, the drive system also includes a backup canned motor pump, which is connected in parallel with the main canned motor pump.

[0012] Specifically, a first tee and a second tee may be arranged at corresponding positions of the oil pipe; wherein the first tee is arranged on the oil pipe whose oil inlets of the main shielded pump and the backup shielded pump are connected to the oil container, and the three pipe openings of the first tee are respectively connected to the oil inlet of the main shielded pump, the oil inlet of the backup shielded pump and the oil outlet pipe of the oil container; the second tee is arranged on the oil pipe connected to the oil inlet of the turbine, and the three pipe openings of the second tee are respectively connected to the oil inlet of the turbine, the oil outlet of the main shielded pump and the oil outlet of the backup shielded pump.

[0013] Taking maintenance needs into consideration, three-valve groups may be provided on the oil pipes between the second tee and the main canned pump, and between the second tee and the standby canned pump.

[0014] Specifically, the oil container is connected to the oil tank through an oil pipe, and a high-pressure pump, such as a plunger pump or a screw pump, is provided on the oil pipe.

[0015] In order to prevent the high-pressure gas in the oil container from entering the oil tank, a one-way check valve is usually provided on the oil pipe between the oil container and the high-pressure pump.

[0016] Specifically, the oil container is provided with a high-pressure gas inlet, and the high-pressure gas is usually hydrogen or nitrogen. The oil container should also be equipped with a liquid level gauge to monitor the liquid level.

[0017] The present invention also discloses a circulating pump comprising the aforementioned driving system, which is particularly suitable for use in hydrocracking fluidized bed reactors and coal chemical reactors.

[0018] The diesel or white oil in the oil container is pumped into the oil circuit inlet of the turbine via a shielded pump, driving the turbine to rotate and then driving the impeller of the circulating pump coaxially connected thereto to rotate; the diesel or white oil is also used as a sealing, lubricating, flushing, cooling and anti-coking medium in the circulating pump system.

[0019] The working principle of the present invention is: The shielded pump extracts diesel (or white oil) from the oil container and transports it to the turbine through the oil pipe, driving the turbine to rotate and then driving the impeller of the circulating pump coaxially connected to it to rotate; most of the oil entering the turbine is sent back to the oil container through the outlet pipe connected to the turbine; the oil entering and leaving the turbine cools the turbine and its internal parts at the same time, and a small amount of oil will flow into the reactor through the shaft seal gap in the circulating pump, which plays the following roles in the circulating pump system, including cooling and lubricating the bearings in the circulating pump, flushing the internal parts of the circulating pump, and preventing the circulating pump from coking. The high-pressure pump arranged between the oil container and the oil tank draws diesel or white oil from the oil tank into the oil container, and maintains and continuously replenishes the amount of diesel or white oil; a gas inlet pipe is arranged above the oil container to connect high-pressure gas (usually hydrogen or nitrogen) to maintain the pressure in the oil container balanced with the pressure in the reactor.

[0020] Compared with the prior art, the technical effects and other advantages of the present invention are prominently reflected in: 1. The overall cost of the circulation pump (including manufacturing cost, operating cost and maintenance cost, etc.) is greatly reduced The present invention uses a turbine and a canned pump connected to a circulating pump to replace a wet motor, which greatly reduces the overall manufacturing cost of the circulating pump. The matching motor can use 380V electricity, and the cost of the power supply system is significantly reduced compared to the aforementioned wet motor. At the same time, the structural design and installation of the present invention are simpler, and there is no need for a series of supporting measures and equipment instruments for cooling that are required for the wet motor of the circulating pump as mentioned above, and the corresponding operating costs and maintenance costs are also significantly reduced; in short, the cost of the circulating pump of the present invention is less than 1 / 15 of the price of the aforementioned imported circulating pump, and it greatly meets the production needs of more companies.

[0021] Low manufacturing costs will inevitably lead to low maintenance costs in the future.

[0022] In particular, wet motors have high requirements on the insulation performance of the liquid medium entering them. The most commonly used liquid medium is diesel, which requires the diesel to be processed in advance to achieve the required insulation indicators. The amount of diesel used can reach several thousand tons / year. The processing costs for complete dehydration and removal of impurities are huge, and it also requires land and carbon emissions. The present invention does not require this processing link and cost expenditure, thereby reducing this part of carbon emissions.

[0023] 2. Significant benefits in energy saving and consumption reduction The present invention uses a canned pump to drive a water turbine to supply power to the circulating pump, and its operating efficiency is more than three times that of the existing wet motor: The specific analysis and calculation are as follows: If an ordinary centrifugal pump can be used as the circulating pump used in the present invention, the motor power only needs 50KW, but the ordinary centrifugal pump cannot be used in this case; at the same time, the prior art shows that the overall efficiency of the existing ordinary centrifugal pump driving the turbine and the transmission system is usually between 45% and 80%. For low-viscosity media, the efficiency of the canned pump may be 5% to 10% lower than that of the ordinary centrifugal pump. Accordingly, when the overall efficiency of the system driving the circulating pump to rotate in the present invention is 50% (the overall efficiency can be made greater than 50% by selecting high-efficiency water pumps and turbines, optimizing system design, and reducing energy losses in pipelines and transmission systems), the power of the canned motor in the present invention is compared with the motor power of an ordinary centrifugal pump, and the maximum required is 100KW.

[0024] On this basis, by comparing the power of a wet motor of 300 KW and a shielded motor of 100 KW, and based on 8760 hours of operation per year and 0.7 yuan per kilowatt-hour, the annual electricity cost savings exceed 1.2 million yuan (this does not include the energy consumption caused by the transformer pressure loss after the high voltage electricity is transformed to 2400V; compared with this, the pump motor of the present invention can directly use the 380V voltage provided by the power grid, while avoiding the energy consumption caused by the transformer pressure loss after the re-transformation).

[0025] 3. Effectively improve system reliability This includes the ability to effectively avoid shutdowns for maintenance by installing a spare shielded pump, while also avoiding some of the risks associated with the aforementioned wet motors, improving system reliability, and avoiding reduced production capacity and efficiency and losses due to shutdowns. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a PID diagram of the circulation pump system described in Example 1 of the present invention, showing the connection relationship and workflow between its components; Figure 2 It is a PID diagram of the circulating pump system described in Example 2 of the present invention, showing the connection relationship and workflow between the various components of the circulating pump system in which a set of spare shielded pumps is added on the basis of Example 1.

[0027] In the figure: 1. Hydrogenation fluidized bed reactor or oil slurry reactor 2. Circulation pump head 3. Turbine 4. Oil pipes 5, 5'. Three-valve group 6. Pump head of main canned pump 6'. Pump head of standby canned pump 7. Motor of main canned pump 7'. Motor of standby canned pump 8. Oil pipe 9. Oil container 10. Liquid level gauge 11. High-pressure pump 12. Oil supply pipe 13. Oil tank 14. One-way check valve 15. Oil supply pipe 16. Gas inlet pipe 17. One-way check valve 18. Oil pipe 19. First three-way 20. Second three-way DETAILED DESCRIPTION Example 1

[0028] A circulating pump system installed in a hydrogenation fluidized bed reactor or an oil slurry reactor 1, such as Figure 1 As shown, including: A circulating pump head 2 and a driving system of the circulating pump installed on the reactor 1; An oil container 9, which contains oil used for sealing, lubrication, flushing, cooling and anti-coking, usually diesel or white oil; A high-pressure pump 11, which is used to pump the oil in the oil tank 13 into the oil container 9; Oil replenishment pipes 12 , 15 ; and an oil tank 13 .

[0029] Wherein, the driving system of the circulating pump comprises: A water turbine 3, which is fixed on the pump head 2 of the circulating pump; The main canned pump comprises a pump head 6 of the main canned pump and a matching motor 7 of the main canned pump.

[0030] The main shaft of the water turbine 3 is coaxially connected to the pump shaft of the circulating pump (i.e., the impeller shaft in the pump head 2 of the circulating pump); The oil circuit inlet of the pump head 6 of the main shielded pump is connected to the oil container 9 through the oil pipe 8, and the oil circuit outlet of the pump head 6 of the main shielded pump is connected to the oil circuit inlet of the turbine 3 through the oil pipe 4; the oil circuit outlet of the turbine 3 is connected to the oil container 9 through the oil pipe 18, and a one-way check valve 17 is arranged on the oil pipe 18.

[0031] The oil in the oil container 9 is pumped into the water turbine 3 through the main shielded pump, driving the water turbine 3 to rotate, thereby driving the circulation pump to rotate and start.

[0032] A high-pressure gas inlet pipe 16 is provided above the oil container 9, and high-pressure gas (usually hydrogen or nitrogen) is connected to maintain the pressure in the oil container 9 balanced with the pressure in the reactor 1; a liquid level gauge 10 for monitoring its liquid level is also installed on the oil container 9; the oil container 9 is connected to the oil tank 13 through oil replenishment pipes 15 and 12, and a high-pressure pump 11 (usually a plunger pump or a screw pump) is connected in series to pump the oil in the oil tank 13 into the oil container 9 in a timely manner to ensure the amount of oil in the oil container 9. In order to prevent the high-pressure gas in the oil container 9 from entering the oil tank 13, a one-way check valve 14 is usually provided on the oil pipe 15 between the oil container 9 and the high-pressure pump 11.

[0033] Considering the need of maintenance, etc., a three-valve group 5 can be provided on the oil pipe 4 between the turbine 3 and the main shielded pump. Example 2

[0034] On the basis of Example 1, in order to avoid the problem of being forced to stop production when the main shielded pump fails to be repaired or replaced, the drive system of the circulating pump is also provided with a spare shielded pump, such as Figure 2 As shown, the standby canned pump includes a standby canned pump head 6' and a matching standby canned pump motor 7', and is connected in parallel with the main canned pump, that is, a first tee 19 and a second tee 20 are arranged on the oil pipes connecting the main canned pump and the standby canned pump with the oil container 9 and the turbine respectively; wherein the first tee 19 is arranged on the oil pipe 8, and the three pipe openings of the first tee 19 are respectively connected with the oil circuit inlet of the main canned pump, the oil circuit inlet of the standby canned pump and the oil outlet pipe of the oil container 9; the second tee 20 is arranged on the oil pipe 4, and the three pipe openings of the second tee 20 are respectively connected with the oil circuit inlet of the turbine 3, the oil circuit outlet of the main canned pump and the oil circuit outlet of the standby canned pump.

[0035] Considering the need for maintenance, three valve groups 5, 5' may be respectively provided on the oil pipes between the second tee 20 and the main canned pump, and between the second tee 20 and the standby canned pump.

Claims

1. The driving system of the circulating pump is characterized by: It includes turbine, main shielded pump, oil container and oil pipe; The oil inlet of the main canned motor pump is connected to the oil container through an oil pipe; The oil circuit outlet of the main canned motor pump is connected to the oil circuit inlet of the turbine through an oil pipe; The oil outlet of the turbine is connected to the oil container through an oil pipe; The main shaft of the water turbine is coaxially connected to the pump shaft of the circulating pump.

2. The drive system according to claim 1, characterized in that: It also includes a backup canned motor pump, which is connected in parallel with the main canned motor pump.

3. The drive system according to claim 1, characterized in that: The oil container is connected with the oil tank through an oil pipe, and a high-pressure pump and a one-way check valve are arranged on the oil pipe.

4. The drive system according to claim 1, characterized in that: The oil container is provided with a high-pressure gas inlet.

5. A circulation pump, comprising the driving system according to any one of claims 1 to 4.

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