A method for controlling the operation of a large-scale cryogenic axial compressor

Abstract

The present invention provides an operation control method for a large-size cryogenic axial flow compressor, which mainly relates to the field of operation control of large-scale rotating mechanical equipment. The air supply pressures of a sealing air source and a heat-insulating air source are both controlled by differential pressure. The low-pressure end of the differential pressure transmitter measures the inlet and outlet air flow pressures of the cryogenic axial flow compressor, and the high-pressure end measures the air supply pressure of the air source. However, when the flow channel pressure in a test bench of the cryogenic axial flow compressor is less than 95KPa, the low-pressure end signal of the differential pressure transmitter is forcibly set to 100Kpa.

Description

Technical Field

[0001] The present invention mainly relates to the field of operation control of large-scale rotating mechanical equipment, and in particular to an operation control method for a large-size deep-cryogenic axial flow compressor. Background Art

[0002] Axial flow compressors are widely used in many industrial production fields such as blast furnace blasting, large-capacity air separation equipment, and catalytic cracking units due to their typical advantages such as large working flow and high operating efficiency. The operating temperature range of most existing axial flow compressors is normal temperature, high temperature or slightly low temperature, with the lowest operating temperature being around 158K. Previously, there were no large-scale deep-cryogenic axial flow compressors in China that had the ability to operate in the deep-cryogenic temperature range of 110K or even lower for a long time and had been put into actual engineering applications. Therefore, the existing operation control technology of axial flow compressors is only applicable to applications with an operating temperature above 158K, and lacks an operation control method for deep-cryogenic working temperature ranges of 110K and below.

[0003] The newly developed large-scale cryogenic axial compressor uses cryogenic nitrogen gasified from 77K cryogenic liquid nitrogen as the working medium. The operating temperature range covers the span from room temperature 300K to 77K cryogenic temperature, and can operate in a cryogenic environment of 110K for a long time. Its operating conditions and control requirements are significantly different from those of most existing axial compressors. Specifically, when the cryogenic working medium flows in the flow channel of the axial compressor, the deep-frozen casing will exchange heat with the internal cavity, and a large number of normal temperature components are installed in the internal cavity; at the same time, the pipelines of the sealing gas source, insulation gas source, lubrication and lifting oil source pass through the casing and enter the internal cavity, and the pipelines will also exchange heat with the casing, which brings new operating control requirements for the axial compressor, such as sealing control, insulation control, and oil source temperature control. At the same time, the axial compressor is the only heat source of the test bench where it is located. After the test bench is completed, the axial compressor needs to continue to operate, relying on the heat generated by its operation to return the test bench to normal temperature. In addition, the deep low temperature operating environment of 110K and below is a dangerous condition for equipment operation. There are multiple controllers of the axial compressor speed. How to ensure that the receiving party has successfully received the control authority during the handover process, how to ensure that the handover party releases the authority, and how to effectively ensure that the speed control authority is in a continuously controlled state; at the same time, the continuous deep low temperature environment requires the axial flow compressor to maintain a stable operating state. After a shutdown failure occurs, how to quickly restart and put it into operation to prevent deformation of the shaft system has put forward new and higher requirements for the reasonable and reliable handover of the axial compressor speed control authority and the continuous stability of the operating state.

[0004] In summary, affected by the cryogenic operating environment, the operation control method, scope, content and focus of large-size cryogenic axial compressors are significantly different from the existing operation control technology. Therefore, it is urgent to propose a control method suitable for the safe and stable operation of large-size cryogenic axial compressors. Summary of the invention

[0005] The purpose of the present invention is to provide an operation control method for a large-sized cryogenic axial flow compressor to solve the operation control problem of the large-sized cryogenic axial flow compressor in actual engineering applications, and to meet the requirements for safe and stable operation of the large-sized cryogenic axial flow compressor.

[0006] The present invention discloses an operation control method for a large-size cryogenic axial flow compressor. The air supply pressures of a sealing air source and a heat-insulating air source are both controlled by differential pressure. The low-pressure end of a differential pressure transmitter measures the inlet and outlet air flow pressures of the cryogenic axial flow compressor, and the high-pressure end measures the air supply pressure of the air source. However, when the flow channel pressure in a cryogenic axial flow compressor test bench is less than 95KPa, the low-pressure end signal of the differential pressure transmitter is forcibly set to 100KPa.

[0007] Furthermore, when the pressure of the flow channel in the test bench is ≥95KPa, the comb teeth seal of the cryogenic axial flow compressor is filled in, and when the pressure of the flow channel in the test bench is <95KPa, the carbon ring seal of the cryogenic axial flow compressor is filled in.

[0008] Furthermore, when the flow channel pressure in the deep cryogenic axial flow compressor test bench is ≥95KPa, the inlet sealing gas supply pressure and the thrust bearing box sealing gas supply pressure are both 20KPa higher than the inlet airflow pressure, the outlet sealing gas supply pressure is 20KPa higher than the outlet airflow pressure, the insulation gas supply pressure of the insulation cavity of the deep cryogenic axial flow compressor coupling is 5KPa higher than the inlet airflow pressure, the inlet insulation cavity insulation gas supply pressure is 10KPa higher than the inlet airflow pressure, the outlet insulation cavity insulation gas supply pressure is 10KPa higher than the outlet airflow pressure, and the through-tube insulation gas supply pressure is 5KPa higher than the outlet airflow pressure; when the flow channel pressure in the test bench is <95KPa, the differential pressure between the sealing gas and insulation gas supply pressures remains unchanged, and the reference end is set to 100KPa.

[0009] Furthermore, multiple temperature measuring points are respectively arranged in the sealed cavity at the inlet and outlet of the deep cryogenic axial flow compressor;

[0010] When one of the temperature measuring points is ≤10℃, the outside of the sealed gas source supply pipeline is heated. When all the temperature measuring points are ≥25℃, the heating stops.

[0011] If the temperature in the sealed cavity continues to drop after heating, when one of the temperature measuring points is ≤5°C, the sealed cavity is heated, and the heating is stopped when all the temperature measuring points are ≥25°C.

[0012] Furthermore, the sealed air source filled into the sealed cavity at the inlet and outlet of the deep cryogenic axial compressor is automatically heated for air supply temperature control. The heating carrier is an electric heater distributed in the sealed air source supply pipeline and the sealed cavity.

[0013] Furthermore, the insulation cavity at the coupling of the cryogenic axial flow compressor is filled with an insulation gas source, and the temperature of the insulation gas source is controlled by heating; the insulation cavity at the inlet and outlet of the cryogenic axial flow compressor is filled with an insulation gas source, and the temperature control of the insulation gas source includes heating control and cooling control. The heating control adopts an automatic heating cycle method, and the cooling control adopts an automatic cooling cycle method.

[0014] Furthermore, the heat-insulating air source heating carrier is an electric heater arranged on the heat-insulating air source supply pipeline, and the heat-insulating air source cooling carrier is a water cooler arranged on the heat-insulating air source supply pipeline; the circulation carriers of heating control and cooling control are both circulation fans.

[0015] Furthermore, the heating control and cooling control switch the gas source path through an electric valve.

[0016] Specific implementation method: When heating control is adopted, the water cooler bypass valve located on the insulated gas source supply pipeline automatically opens and the water cooler automatically stops; when cooling control is adopted, the water cooler bypass valve located on the insulated gas source supply pipeline automatically closes and the water cooler is automatically put into operation.

[0017] Furthermore, multiple temperature measuring points are respectively set in the insulation cavity at the coupling, inlet and outlet of the deep low-temperature axial compressor. Heating is performed when one of the temperature measuring points is ≤15°C, and heating is stopped when all the temperature measuring points are ≥30°C.

[0018] Furthermore, the circulating fan located on the insulated air supply pipeline does not stop immediately after the electric heater stops, but stops automatically when the outlet temperature of the electric heater is ≤30°C.

[0019] Furthermore, a 70% limit is set on the power of the driving power regulator of the electric heater on the insulated gas supply pipeline, and the electric heater operates in a temperature limit control mode: when the outlet temperature of the electric heater is ≥90°C, it automatically stops, and starts again when the outlet temperature is ≤70°C.

[0020] Furthermore, cooling is performed when one of the temperature measuring points in the heat preservation cavity at the inlet and outlet of the deep low temperature axial flow compressor is ≥45°C, and cooling is stopped when all the temperature measuring points are ≤30°C.

[0021] By setting up a sealing gas source with heating function based on the differential pressure control method and an insulation gas source with heating and cooling functions, it is used for the insulation of the sealing cavity of a large-size deep-cryogenic axial compressor and the insulation and cooling of the insulation cavity, which plays a good role in thermal insulation and normal temperature equipment protection and meets the operation control requirements from normal temperature 300K to 77K.

[0022] Furthermore, the oil source temperature is controlled in combination by an oil tank heater and a self-operated temperature control valve. The oil tank heater is equipped with an independent heating circulation loop. When the oil source heater is started, the heating circulation loop is opened synchronously to circulate and heat the oil. The oil source heater continues to operate during the operation of the deep low-temperature axial flow compressor. The self-operated temperature control valve is respectively connected to the oil source cooler outlet and the oil tank outlet, and the cold oil cooled by the cooler is mixed with the hot oil at the oil tank outlet to cool the oil source.

[0023] Furthermore, the internal pressure of the oil tank is first pumped down to a slight negative pressure of -0.8 KPa, and then the compressor jacking oil source, high-voltage motor jacking oil source, and lubricating oil source are controlled in sequence to normal pressure.

[0024] Furthermore, the speed of the cryogenic axial flow compressor adopts a combined control method of a high-voltage frequency converter and a motor mechanical cranking device, and the following working conditions are distinguished: the first startup of the cryogenic axial flow compressor after a long period of inactivity adopts a motor mechanical cranking device to control the speed at 10r / min; the daily startup adopts a high-voltage frequency converter to control the speed at 40r / min; the motor mechanical cranking device also retains the long-term steady-state cranking function after the normal shutdown of the cryogenic axial flow compressor, controlling the speed at 2r / min-10r / min, and the operation during the steady-state cranking ensures a continuous and stable supply of air source, lubrication and lifting oil source, cooling water source, etc.

[0025] Furthermore, before starting the high-voltage frequency converter, the motor mechanical cranking device is first started to perform a functional test, and the speed is controlled to 10r / min and the running time is 5min; then the motor mechanical cranking device does not stop to keep the deep low-temperature axial flow compressor in operation, and the high-voltage frequency converter is started directly. When the deep low-temperature axial flow compressor accelerates to a speed exceeding 10r / min, the cranking device automatically disengages, slows down and stops by itself.

[0026] Furthermore, there is a control authority handover and response between the local control of the deep cryogenic axial flow compressor speed and the remote control of the deep cryogenic axial flow compressor test bench, and identification is based on the status flag: when the status flag is "1", the speed control authority is located locally in the deep cryogenic axial flow compressor, and when the status flag is "0", the speed control authority is located remotely in the deep cryogenic axial flow compressor test bench; the handover and response process is: the party with the current speed control authority transfers the control authority first, and the receiving party can receive the control authority.

[0027] Furthermore, the status flag is triggered according to the handshake response result, and changes only after local or remote manual confirmation. The specific control method is as follows:

[0028] (1) The low-temperature axial compressor manually transfers the speed control authority locally, and the status flag is "1";

[0029] (2) The cryogenic axial compressor test bench receives the speed control authority remotely and manually, and the status flag is "0";

[0030] (3) The speed control authority of the deep low temperature axial flow compressor test bench is manually transferred remotely, and the status flag is "0";

[0031] (4) The deep-cryogenic axial compressor manually receives the speed control authority locally, and the status flag is "1".

[0032] Furthermore, during the operation of the cryogenic axial compressor, if the safety interlock is triggered locally or remotely by the cryogenic axial compressor test bench, the cryogenic axial compressor slows down or stops according to the safety interlock method, and the status flag is automatically forced to be set to "1" synchronously, and the speed control authority automatically returns to the local cryogenic axial compressor.

[0033] Furthermore, when the status flag is "0", the deep low-temperature axial compressor locally implements operating status monitoring, and the monitoring objects include: shaft system operating data, blade tip clearance data, casing stress data, noise data, torque data, operating condition status, low-voltage power distribution status, and data and status of operating control objects.

[0034] Furthermore, the monitoring objects are all set with alarm and safety interlock methods. After the alarm or safety interlock is triggered, the local operator needs to manually confirm it locally on the cryogenic axial compressor; in particular, when the cryogenic axial compressor is operating in a cryogenic environment, if the safety interlock triggers a shutdown, it needs to be restarted as soon as possible and maintained in operation. There is a priority for the starting method: the high-voltage inverter starts first, and the motor mechanical cranking device starts second.

[0035] Furthermore, after the remote control of the cryogenic axial compressor test bench is completed and the control authority is handed over, the local cryogenic axial compressor continues to control the compressor operation and perform step-by-step speed reduction, continuously generating heat until the temperature of the flow channel in the test bench and the temperature of the internal steel structure parts return to normal temperature; then the local control speed is reduced to 40r / min until the shaft system temperature of the cryogenic axial compressor is ≤45℃ and then it stops.

[0036] Furthermore, after the speed drops to 0, the lubrication and lifting oil sources are stopped in the order of lubricating oil source, high-voltage motor lifting oil source, and compressor lifting oil source, and the operation guarantee air source is stopped, and finally the internal pressure of the oil tank is restored to normal pressure.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] A sealing gas source with heating function based on the differential pressure control method and an insulation gas source with heating and cooling functions are specially set up for the insulation of the sealing cavity of a large-size deep-cryogenic axial compressor and the insulation and cooling of the insulation cavity, which plays a good role in insulation and normal temperature equipment protection, and meets the operation control requirements from normal temperature 300K to 77K; a circulation control method for the insulation gas source is adopted, and the heat generated by the electric heater is circulated to heat the insulation gas source. The insulation gas source circulates in the pipeline, effectively reducing heat loss and saving gas source consumption; the influence of deep-cryogenic conditions on the temperature control of the lubrication and jacking oil sources, and the impact of leakage of the sealing gas source and the insulation gas source on the oil return volume of the oil source are taken into consideration. In order to avoid the impact, the oil tank heater is used to continuously run to heat the oil source to offset the cold source input of the cryogenic casing to the oil source pipeline, and the pressure control timing of the oil tank, the lifting oil source and the lubricating oil source is clarified to effectively ensure the smooth return of oil; considering the temperature recovery of the test bench where the large-sized deep-cryogenic axial compressor is located and the safe disposal requirements of the equipment in the state of sudden shutdown of the unit, the large-sized deep-cryogenic axial compressor is continuously operated to generate heat for temperature recovery, and a combination of high-voltage frequency converter and motor mechanical cranking device is used to implement emergency start-up under abnormal conditions, so that the equipment can be restored to a safe state as soon as possible; considering the long-term cranking demand, the long-term steady-state cranking function of the motor mechanical cranking device is used to stably supply the equipment required for the operation of the unit. External conditions are taken into account to improve the shaft stability of large-sized deep-cryogenic axial compressors; the negative pressure working state when the flow channel pressure in the test bench where the large-sized deep-cryogenic axial compressor is located is taken into account, and the reference end pressure is automatically set to the normal pressure state to ensure the continuous and stable supply of sealing gas source and insulation gas source under the differential pressure control mode; the hardware redundancy of the sealing gas source heater is adopted and the hierarchical judgment of the control logic is implemented to ensure that the temperature of the sealing cavity is always at normal temperature, effectively isolating the deep-cryogenic working medium in the flow channel of the large-sized deep-cryogenic axial compressor; the speed combination control method is adopted and the implementation conditions and operation procedures are clearly defined. Compared with the existing technology, the startup method is more reasonable and effective, especially the increase The functional test of the motor mechanical cranking device has been added, and the reliability of emergency start-up and the safety of the equipment are higher; the mutually exclusive handover mechanism of the speed control authority is clarified, and a handshake response method based on the status bit is adopted. Compared with the existing technology, it strictly ensures that the speed control authority of the large-size deep-cryogenic axial flow compressor is in a controllable state, effectively reducing the risk of loss of control; the operation control method of the present invention implements the start-up, operation and control of the large-size deep-cryogenic axial flow compressor, and achieves the expected purpose and effect, proving that the operation control method is reasonable and effective, and effectively guarantees the normal operation of the equipment, especially suitable for deep-cryogenic operating conditions of 110K and below, and improves the safe and stable operation capability of the axial flow compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the operation control of the deep cryogenic axial flow compressor of the present invention;

[0040] Figure 2 Schematic diagram of switching the heat preservation gas source path of the deep cryogenic axial flow compressor of the present invention;

[0041] Figure 3 This is a flow chart of the air source control for the operation guarantee of the deep low temperature axial flow compressor of the present invention;

[0042] Figure 4 The present invention is a flow chart of the lubrication and lifting oil source control of a deep low temperature axial flow compressor. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0044] Example 1

[0045] A large-size cryogenic axial compressor operation control method, the operation control objects include: operation guarantee gas source, lubrication and lifting oil source, cooling water source, high-voltage inverter, high-voltage motor, motor mechanical turning device, etc. The operation control range includes the cryogenic axial compressor test bench position control response. The main control functions involved are as follows: Figure 1 As shown, it includes: operation guarantee air source control, lubrication and lifting oil source control, speed combination control, speed handover and control, etc. Among them, operation guarantee air source control includes sealing air source control and insulation air source control; lubrication and lifting oil source control includes oil source temperature control and oil source pressure control; speed combination control includes high-voltage inverter control and motor mechanical turning device control; speed handover and control includes local and remote authority handover and local monitoring.

[0046] The operation guarantee air source includes a sealing air source and an insulation air source, wherein the sealing air source is respectively filled into the comb seals and carbon ring seals in the sealing cavities at the inlet, outlet and thrust bearing box of the deep-cryogenic axial flow compressor; the insulation air source is respectively filled into the insulation cavity at the coupling, inlet and outlet of the deep-cryogenic axial flow compressor and the cable inlet and outlet penetration tube of the outer casing.

[0047] Among them, the sealing gas source is filled into the comb tooth seal or the carbon ring seal, which needs to be judged according to the pressure of the flow channel inside the deep low temperature axial flow compressor test bench: when the pressure of the flow channel inside the test bench is ≥95KPa, the comb tooth seal is filled; when the pressure of the flow channel inside the test bench is <95KPa, the carbon ring seal is filled.

[0048] Among them, the sealing gas source is filled into the sealing cavity at the inlet and outlet of the deep low-temperature axial flow compressor, and the air supply temperature is controlled by an automatic heating method. The heating carrier is an electric heater distributed in the sealing gas source supply pipeline and the sealing cavity.

[0049] Among them, the insulation gas source is filled into the insulation cavity at the coupling of the deep low-temperature axial flow compressor, and the air supply temperature is controlled by an automatic heating circulation method. The heating carrier is an electric heater arranged on the insulation gas source supply pipeline, and the circulation carrier is a circulation fan arranged on the insulation gas source supply pipeline.

[0050] Among them, the temperature control of the insulation gas source filled into the insulation cavity at the inlet and outlet of the deep low temperature axial compressor includes heating control and cooling control. The heating control is suitable for low temperature conditions, and the cooling control is suitable for normal temperature conditions. Therefore, it can effectively cover the working temperature range from normal temperature 300K to deep low temperature 77K. The heating control adopts an automatic heating cycle method, and the heating carrier is an electric heater set on the insulation gas source supply pipeline; the cooling control adopts an automatic cooling cycle method, and the cooling carrier is a water cooler set on the insulation gas source supply pipeline. The circulation carriers of heating control and cooling control are both circulating fans set on the insulation gas source supply pipeline. The circulating fan runs continuously, driving the heated or cooled gas source into the insulation cavity, and then into the front end of the electric heater or water cooler through the exhaust pipe, so as to replace heat in a cycle. The power of the driving power regulator of the electric heater is set to a 70% limit, and the operation of the electric heater adopts a temperature limit control mode: when the outlet temperature of the electric heater is ≥90℃, it will stop automatically, and start again when the outlet temperature is ≤70℃, to prevent excessive heating or frequent start and stop to reduce the service life.

[0051] like Figure 2 As shown, there is an automatic switching method for the air source path for the heat preservation air source heating control and the cooling control, and the switching carrier is an electric valve installed on the air source path. The specific implementation method is as follows:

[0052] When heating control is adopted, the water cooler bypass electric valve located on the insulated gas supply pipeline opens automatically, so that the gas source does not flow through the water cooler, and the water cooler stops automatically, which can effectively reduce heat loss; when cooling control is adopted, the water cooler bypass electric valve closes automatically, so that the gas source flows through the water cooler, and the water cooler is automatically put into operation.

[0053] like Figure 3 As shown, the implementation method of the air source control for the operation guarantee of the deep low temperature axial flow compressor is as follows:

[0054] The supply pressure of the sealing gas source and the insulation gas source are both controlled by differential pressure. The low-pressure end of the differential pressure transmitter measures the inlet and outlet air flow pressure of the cryogenic axial flow compressor, and the high-pressure end measures the gas supply pressure of the gas source. The pressure range of the inner flow channel of the cryogenic axial flow compressor test bench covers normal pressure, boost pressure and negative pressure conditions. When the inner flow channel pressure is less than 95KPa, the low-pressure end signal of the differential pressure transmitter is forced to be set to 100KPa.

[0055] The differential pressure control implementation method is as follows:

[0056] When the flow channel pressure in the cryogenic axial compressor test bench is ≥95KPa:

[0057] 1. The inlet sealing gas supply pressure and the thrust bearing box sealing gas supply pressure are both 20KPa higher than the inlet air flow pressure;

[0058] 2. The outlet sealing gas supply pressure is 20KPa higher than the outlet air flow pressure;

[0059] 3. The insulation gas supply pressure of the coupling insulation cavity is 5KPa higher than the inlet air flow pressure;

[0060] 4. The insulation gas supply pressure of the inlet insulation cavity is 10KPa higher than the inlet air flow pressure;

[0061] 5. The insulation gas supply pressure of the outlet insulation cavity is 10KPa higher than the outlet air flow pressure;

[0062] 6. The insulation gas supply pressure through the tube is 5KPa higher than the outlet air flow pressure.

[0063] When the flow channel pressure in the test bench is less than 95KPa, the differential pressure between the sealing gas and the insulation gas supply pressure is the same as the above value, and the reference end is set to 100KPa.

[0064] Among them, multiple temperature measuring points are set in the sealed cavity at the entrance and exit. When one of the temperature measuring points is ≤10℃, the electric heater located on the sealed gas source supply pipeline is automatically turned on, and when all the temperature measuring points are ≥25℃, the electric heater is automatically stopped. Selecting one of the temperature measuring points to automatically judge the electric heater, and all the temperature measuring points to automatically judge the electric heater, can ensure that the entire space in the sealed cavity is effectively insulated to prevent local cold.

[0065] In particular, if the temperature in the sealed cavity continues to drop after the electric heater located on the sealed gas supply pipeline is put into operation, when one of the temperature measuring points is ≤5°C, the electric heater located in the sealed cavity will be automatically put into operation. The electric heater has no heating path and can directly heat the insulation cavity; when all temperature measuring points are ≥25°C, the electric heater will automatically stop.

[0066] Among them, multiple temperature measuring points are set in the insulation cavity at the coupling, inlet and outlet of the deep low-temperature axial compressor. When one of the temperature measuring points is ≤15℃, the electric heater located on the insulation gas source supply pipeline is automatically turned on. When all temperature measuring points are ≥30℃, the electric heater automatically stops to ensure that all spaces in the insulation cavity are effectively insulated. The circulating fan located on the insulation gas source supply pipeline does not stop immediately after the electric heater stops. In this way, the residual heat in the outlet and air supply pipeline of the electric heater after it stops can be continuously filled into the insulation cavity through the circulating fan, continuously supplying heat source to the insulation cavity, and automatically stops when the outlet temperature of the electric heater is ≤30℃.

[0067] Among them, when one of the temperature measuring points in the insulation cavity at the inlet and outlet is ≥45℃, the water cooler located on the insulation gas supply pipeline is automatically put into operation, and when all temperature measuring points are ≤30℃, the water cooler is automatically stopped.

[0068] The lubrication and lifting oil sources include: a lubrication oil source, a compressor lifting oil source, and a high-voltage motor lifting oil source. The cryogenic axial compressor and the high-voltage motor are supplied with oil from the same lubrication oil source and from lifting oil sources with different oil circuits. All oil sources are stored in the same oil tank.

[0069] like Figure 4 As shown, the implementation method of the deep low temperature axial flow compressor lubrication and jacking oil source control is as follows:

[0070] The oil source temperature is controlled in combination by an oil tank heater and a self-acting temperature control valve. The oil tank heater is equipped with an independent heating circulation loop. The heater start temperature is oil source temperature ≤25°C, and the stop temperature is oil source temperature ≥45°C. When the heater is started, the heating circulation loop is opened synchronously to circulate and heat the oil to prevent local heating from affecting the oil quality. The heater continues to operate during the operation of the cryogenic axial compressor to offset the cold source input of the cryogenic casing to the oil source pipeline. The self-acting temperature control valve is respectively connected to the oil source cooler outlet and the oil tank outlet, and the cold oil cooled by the cooler is mixed with the hot oil at the oil tank outlet to cool the oil source.

[0071] The pressure control method of the oil source is as follows:

[0072] When starting, first pump the internal pressure of the oil tank to a slight negative pressure of -0.8KPa, and then control the compressor jacking oil source, high-voltage motor jacking oil source, and lubricating oil source to normal pressure in turn; when stopping, after the deep-cryogenic axial flow compressor is shut down and the speed drops to 0, the lubrication and jacking oil sources are stopped in the order of lubricating oil source, high-voltage motor jacking oil source, and compressor jacking oil source, and the operation guarantee gas source is stopped, and finally the internal pressure of the oil tank is restored to normal pressure.

[0073] The speed of the deep-cryogenic axial compressor adopts a combined control method of a high-voltage frequency converter and a motor mechanical cranking device, and distinguishes the following working conditions: the first startup after a long period of inactivity adopts a motor mechanical cranking device to preheat the shaft system at a low speed. At the same time, the reliability of the motor mechanical cranking device can be tested, and the speed is controlled at 10r / min; the daily startup adopts a high-voltage frequency converter to control the speed at 40r / min.

[0074] In addition, the motor mechanical cranking device also retains the long-term steady-state cranking function after the deep-cryogenic axial compressor is normally shut down, controlling the speed to 2r / min-10r / min. Long-term low-speed operation can keep the shaft system in a relatively stable state to prevent flexible bending from affecting formal operation; during steady-state cranking, operation ensures a continuous and stable supply of air source, lubrication and jacking oil source, cooling water source, etc.

[0075] Among them, before starting the high-voltage frequency converter, first start the motor mechanical cranking device for functional inspection to ensure that the high-voltage frequency converter can be put into operation in time and smoothly when the starting conditions are not met, and restore the deep-cryogenic axial flow compressor to the operating state as soon as possible, control the speed to 10r / min, and the operating time is 5min; then the motor mechanical cranking device does not stop, and the high-voltage frequency converter is started directly while the deep-cryogenic axial flow compressor remains in the operating state. When it accelerates to a speed exceeding 10r / min, the cranking device automatically disengages, slows down and stops by itself.

[0076] There is a control authority handover and response between the local control of the deep cryogenic axial compressor speed and the remote control of the deep cryogenic axial compressor test bench, and it is identified based on the status flag: when the status flag is "1", the speed control authority is located locally, and when the status flag is "0", the speed control authority is located remotely. The handover and response process is: the party with the current speed control authority transfers the control authority first, and the receiving party can receive the control authority.

[0077] Among them, the status flag is triggered according to the handshake response result, and it will only change after local or remote manual confirmation. The specific control method is as follows:

[0078] The local manual transfer of speed control authority of the deep-cryogenic axial compressor is completed, and the status flag is "1";

[0079] The deep low temperature axial compressor test bench remotely and manually receives the speed control authority, and the status flag is "0";

[0080] The deep low temperature axial compressor test bench remotely and manually transferred the speed control authority, and the status flag was "0";

[0081] The cryogenic axial compressor receives the speed control authority locally and manually, and the status flag is "1".

[0082] In particular, during the operation of the cryogenic axial compressor, if the safety interlock is triggered locally or remotely, the cryogenic axial compressor will slow down or stop according to the safety interlock method, and the status flag will be automatically forced to "1" at the same time, and the speed control authority will automatically return to the local cryogenic axial compressor, making it convenient for local operators to carry out equipment inspections under the premise that the speed can be controlled.

[0083] Among them, when the status flag is "0", the deep low-temperature axial compressor can still control all operation control objects locally, which is convenient for local operators to intervene at any time to ensure that the equipment is in a controllable and safe state; local operation status monitoring is implemented synchronously, and the monitoring objects include: shaft system operation data, blade tip clearance data, casing stress data, noise data, torque data, operating condition status, low-voltage power distribution status, and data and status of operation control objects.

[0084] The above-mentioned monitoring objects are all equipped with alarm and safety interlock methods. After the alarm or safety interlock is triggered, the local operator needs to manually confirm it locally on the cryogenic axial compressor; in particular, when the cryogenic axial compressor is operating in a cryogenic environment, if the safety interlock triggers a shutdown, it must be restarted as soon as possible and maintained in operation. There is a priority for the starting method: the high-voltage inverter starts first, followed by the motor mechanical cranking device.

[0085] After the remote control of the deep low temperature axial flow compressor test bench is completed and the speed control authority is handed over, the deep low temperature axial flow compressor local continues to control the compressor operation and performs step-by-step speed reduction. The specific steps are determined according to the current temperature of the test bench and the cooling slope. The heat generated offsets the cooling capacity of the inner flow channel of the test bench until the temperatures of the inner flow channel and the internal steel structure parts return to normal temperature. Then the local control speed is reduced to 40r / min until the shaft system temperature of the deep low temperature axial flow compressor is ≤45°C and then it stops.

[0086] The above are the implementation methods listed in this embodiment, but this embodiment is not limited to the above optional implementation methods. Those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods. Anyone can derive other various forms of implementation methods under the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the scope of protection of this embodiment. The scope of protection of this embodiment shall be based on the definition in the claims, and the description can be used to interpret the claims.

Claims

1. A large-scale cryogenic axial compressor operation control method, characterized in that: The supply pressure of the sealing gas source and the insulation gas source are both controlled by differential pressure. The low-pressure end of the differential pressure transmitter measures the inlet and outlet air flow pressures of the cryogenic axial flow compressor, and the high-pressure end measures the gas supply pressure of the gas source. However, when the flow channel pressure in the cryogenic axial flow compressor test bench is less than 95KPa, the low-pressure end signal of the differential pressure transmitter is forced to be set to 100KPa. When the flow channel pressure in the deep cryogenic axial flow compressor test bench is ≥95KPa, the inlet sealing gas supply pressure and the thrust bearing box sealing gas supply pressure are both 20KPa higher than the inlet air flow pressure, the outlet sealing gas supply pressure is 20KPa higher than the outlet air flow pressure, the insulation gas supply pressure of the deep cryogenic axial flow compressor coupling insulation cavity is 5KPa higher than the inlet air flow pressure, the inlet insulation cavity insulation gas supply pressure is 10KPa higher than the inlet air flow pressure, the outlet insulation cavity insulation gas supply pressure is 10KPa higher than the outlet air flow pressure, and the through-tube insulation gas supply pressure is 5KPa higher than the outlet air flow pressure; when the flow channel pressure in the test bench is <95KPa, the differential pressure between the sealing gas and insulation gas supply pressures remains unchanged, and the reference end is set to 100KPa.

2. A large-size cryogenic axial compressor operation control method according to claim 1, characterized in that: Multiple temperature measuring points are set in the sealed cavity at the inlet and outlet of the cryogenic axial compressor; When one of the temperature measuring points is ≤10℃, the outside of the sealed gas source supply pipeline is heated. When all the temperature measuring points are ≥25℃, the heating stops. If the temperature in the sealed cavity continues to drop after heating, when one of the temperature measuring points is ≤5°C, the sealed cavity is heated, and the heating is stopped when all the temperature measuring points are ≥25°C.

3. The operation control method of a large-size cryogenic axial compressor according to claim 1, characterized in that: The insulation gas source is filled into the insulation cavity at the coupling of the cryogenic axial flow compressor and at the inlet and outlet of the cryogenic axial flow compressor. The temperature control of the insulation gas source includes heating control and / or cooling control.

4. A large-size cryogenic axial compressor operation control method according to claim 3, characterized in that: Multiple temperature measuring points are respectively set in the insulation cavity at the deep-cryogenic axial flow compressor coupling, the inlet and the outlet of the deep-cryogenic axial flow compressor. Heating is carried out when one of the temperature measuring points is ≤15°C, and heating is stopped when all the temperature measuring points are ≥30°C.

5. The operation control method of a large-size cryogenic axial compressor according to claim 2, characterized in that: The oil source temperature is controlled in combination by an oil tank heater and a self-operated temperature control valve. The oil tank heater is equipped with an independent heating circulation loop. When the oil source heater is started, the heating circulation loop is opened synchronously to circulate and heat the oil. The oil source heater continues to operate during the operation of the deep low-temperature axial flow compressor. The self-operated temperature control valve is respectively connected to the oil source cooler outlet and the oil tank outlet, and the cold oil cooled by the cooler is mixed with the hot oil at the oil tank outlet to cool the oil source.

6. The operation control method of a large-size cryogenic axial compressor according to claim 1, characterized in that: The speed of the cryogenic axial compressor adopts a combined control method of a high-voltage frequency converter and a motor mechanical cranking device, and the following working conditions are distinguished: the first startup of the cryogenic axial compressor after a long period of inactivity adopts a motor mechanical cranking device to control the speed at 10r / min; the daily startup adopts a high-voltage frequency converter to control the speed at 40r / min; the motor mechanical cranking device also retains the long-term steady-state cranking function after the normal shutdown of the cryogenic axial compressor, controlling the speed at 2r / min-10r / min, and the operation during the steady-state cranking ensures a continuous and stable supply of air source, lubrication and jacking oil source and cooling water source.

7. The operation control method of a large-size cryogenic axial compressor according to claim 1, characterized in that: There is a control authority handover and response between the local speed control of the cryogenic axial compressor and the remote control of the cryogenic axial compressor test bench, and identification is based on the status flag: when the status flag is 1, the speed control authority is located locally in the cryogenic axial compressor; when the status flag is 0, the speed control authority is located remotely in the cryogenic axial compressor test bench; the handover and response process is: the party with the current speed control authority transfers the control authority first, and the receiving party can receive the control authority.

8. The operation control method of a large-size cryogenic axial compressor according to claim 7, characterized in that: After the remote control of the cryogenic axial compressor test bench is completed and the control authority is handed over, the local control of the cryogenic axial compressor continues to control the compressor operation and perform step-by-step speed reduction, continuously generating heat until the temperature of the flow channel and the temperature of the internal steel structure parts in the test bench return to normal temperature; then the local control speed is reduced to 40r / min until the shaft system temperature of the cryogenic axial compressor is ≤45℃ and then it stops.

9. The operation control method of a large-size cryogenic axial compressor according to claim 1, characterized in that: After the speed drops to 0, stop lubrication and lifting oil sources in the order of lubricating oil source, high-voltage motor lifting oil source, and compressor lifting oil source, wait for the operation guarantee air source to stop, and finally restore the internal pressure of the oil tank to normal pressure.

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