Oil depot variable frequency throttling combined regulation loading system and control method

Abstract

The present invention belongs to the technical field of flow control, and specifically relates to a variable frequency throttling combined regulation loading system and a control method for an oil depot, comprising a pumping system, a main oil supply pipeline, and a branch loading pipeline, wherein the pumping system is connected to the main oil supply pipeline, and the main oil supply pipeline is also connected to at least two branch loading pipelines. The present invention can solve the problems of low efficiency, large energy loss, and easy safety accidents in the prior art of manual operation of loading oil depots.

Description

Technical Field

[0001] The invention belongs to the technical field of flow control, and in particular relates to an oil depot variable frequency throttling combined regulating loading system and a regulating method. Background Art

[0002] During the flow of petroleum and chemical products, static electricity is generated due to the internal friction of liquid molecules and the friction between liquid molecules and pipelines or container walls. The accumulation and discharge of static electricity may lead to accidents such as fire and explosion. In order to avoid accidents caused by static electricity accumulation, pipelines or containers for transporting petroleum and chemical products need to be equipped with static electricity conduction facilities, and the flow rate of liquid products also needs to be controlled. The "Petroleum Depot Design Code" (GB50074) stipulates that the liquid flow rate in the crane pipe should not be greater than 1m / s before the crane pipe is immersed in the liquid during loading, and should not be greater than 4.5m / s after it is immersed in the liquid).

[0003] In the design of loading process, it is common to have one pump corresponding to 2-3 loading cranes. For this process, loading operation often involves process switching. Sometimes the newly arrived tank truck needs to be loaded, and sometimes the tank truck that has been loaded needs to be closed. These process switching will cause flow fluctuations.

[0004] Due to the above reasons, when loading, operators are usually required to manually adjust the valve to control the loading flow rate not to exceed the specified value. If the adjustment is not made in time, there is a risk of exceeding the flow rate limit, which may cause an accident in serious cases.

[0005] The above-mentioned method of achieving flow regulation by adjusting the valve opening is called throttling regulation. Its advantages are simple system and continuous flow regulation, but its disadvantages are that throttling leads to energy loss and it is difficult to achieve automatic control. Another corresponding regulation method is frequency conversion regulation, which uses variable speed motors. The frequency converter uses flow or pressure as a control signal to change the motor output, thereby achieving flow regulation.

[0006] Since the loading flow rate needs to be adjusted according to the on-site conditions when loading each parking space, it is difficult for the inverter to achieve flow control output; the frequency conversion adjustment through pressure control cannot meet the relevant requirements. Therefore, it is necessary to use manual adjustment valves to control the loading flow rate. However, manual adjustment valves have a large workload and low efficiency. If the adjustment is not timely, it may cause safety accidents due to excessive flow rate. Summary of the invention

[0007] The invention provides an oil depot variable frequency throttling combined regulation loading system and a control method, so as to solve the problems of low efficiency, large energy loss and easy safety accidents in the prior art of manual operation of oil depot loading.

[0008] The first aspect of the present invention provides an oil depot variable frequency throttling combined regulation loading system, comprising a pumping system, a main oil supply pipeline, and a branch loading pipeline, wherein the pumping system is connected to the main oil supply pipeline, and the main oil supply pipeline is also connected to at least two branch loading pipelines respectively;

[0009] The main oil supply pipeline includes an inlet valve, an outlet valve, and a pressure transmitter. The inlet valve is arranged at the front end of the pumping system, the pressure transmitter is arranged at the rear end of the pumping system, the outlet valve is arranged at the rear end of the pressure transmitter, and the pressure transmitter is electrically connected to the pumping system;

[0010] The branch loading pipeline includes a mass flow meter, a three-stage regulating valve, an oil filling valve, and a lifting pipe. The front end of the mass flow meter is connected to the main oil supply pipeline, and the rear end of the mass flow meter is connected to the three-stage regulating valve, the oil filling valve, and the lifting pipe in sequence.

[0011] As a preferred embodiment of the first aspect of the present invention, the pumping system includes a variable frequency centrifugal pump, a filter, a centrifugal pump outlet pressure gauge, and a check valve. The filter is arranged at the inlet end of the variable frequency centrifugal pump, and the outlet end of the variable frequency centrifugal pump is also connected to the centrifugal pump outlet pressure gauge and the check valve in sequence.

[0012] As a preferred embodiment of the first aspect of the present invention, the main oil supply pipeline further includes an emergency shut-off valve, and the emergency shut-off valve is located between the outlet valve and the branch loading pipeline.

[0013] As a preferred embodiment of the first aspect of the present invention, a bypass pipeline is further provided between the end of the inlet valve and the front end of the outlet valve of the main oil supply pipeline, and a reflux valve is provided on the bypass pipeline.

[0014] As a preferred embodiment of the first aspect of the present invention, the branch loading pipeline further includes a throttle valve, and the throttle valve is arranged between the three-stage regulating valve and the oil filling valve.

[0015] As a preferred embodiment of the first aspect of the present invention, the branch loading pipeline also includes a flowmeter inlet pressure gauge and a flowmeter inlet valve. The flowmeter inlet pressure gauge is located at the front end of the mass flowmeter, and the flowmeter inlet valve is located at the front end of the flowmeter inlet pressure gauge. The flowmeter inlet valve is connected to the main oil supply pipeline.

[0016] The second aspect of the present invention further provides a method for controlling a variable frequency throttling combined regulation loading system of an oil depot, comprising:

[0017] Step 1: Set the inverter target value of the variable frequency centrifugal pump to the maximum, fully open all valves of the main oil supply pipeline and each branch loading pipeline, and control the loading flow rate to reach the upper limit of 4.5m / s by adjusting the opening of the throttle valve, and record the opening of each throttle valve as the maximum opening at this time;

[0018] Step 2, recording the pressure value of the variable frequency centrifugal pump outlet pressure gauge when the loading flow rate is at an upper limit, and setting the pressure value as a parameter value of the frequency converter of the variable frequency centrifugal pump;

[0019] Step 3: each branch loading pipeline is loaded separately, and the throttle valve is further closed to make the loading flow rate not greater than the upper limit of the loading flow rate of 4.5m / s; lock the opening

[0020] Step 4, adjusting the small flow opening of the three-stage regulating valve to control the loading flow to be less than the safety value of 1m / s;

[0021] Step 5: In the initial stage of loading, the three-stage regulating valve is controlled to have a small flow opening, and the loading flow is less than the safety value of 1m / s. When the liquid level is above the crane pipe, the opening of the three-stage regulating valve is controlled to make the loading flow not greater than the upper limit of 4.5m / s.

[0022] As a preferred embodiment of the second aspect of the present invention, step one also includes pressure calibration of the mass flow meter. When the loading flow reaches an upper limit of 4.5 m / s, the value of the flow meter inlet pressure gauge is verified. If the value is greater than the operating value of the mass flow meter, the throttle valve is reduced so that the value of the flow meter inlet pressure gauge meets the operating value, and the maximum opening of the throttle valve is updated.

[0023] As a preferred embodiment of the second aspect of the present invention, step three further includes locking the throttle valve opening.

[0024] As a preferred embodiment of the second aspect of the present invention, locking the throttle valve is achieved by removing a handle or a hand wheel of the throttle valve.

[0025] The beneficial effects of the present invention are:

[0026] The three-stage regulating valve is used to control the loading flow rate, which can switch the initial flow rate and the loading flow rate to achieve smooth switching of the loading state. A throttle valve is set in each branch loading pipeline to adjust the resistance coefficient in the pipeline. The preset throttle valve opening can ensure that the flow rate does not exceed the maximum flow limit under the working conditions of the centrifugal pump, ensure that the instantaneous flow rate does not exceed the standard during loading, and ensure the safety of the loading operation.

[0027] A pressure transmitter is installed on the main oil supply pipeline. When the flow of each branch loading pipeline changes, it will affect the flow of the main oil supply pipeline in real time. At this time, the pressure transmitter transmits the real-time pressure data of the main oil supply pipeline to the frequency converter of the pumping system, and controls the working state of the centrifugal pump through the frequency converter to realize the flow regulation of the whole system.

[0028] The present invention realizes automatic regulation of system flow through combined frequency conversion regulation and throttling regulation, and utilizes the characteristics of a three-stage regulating valve. The state of each valve can be controlled by a PLC or an industrial computer. During the loading operation, the loading operator only needs to open the valves in sequence, and the flow during the oil loading process is automatically controlled by the system; after the delivery is completed, only the valve needs to be closed, and the system automatically adjusts the output. After the last car is loaded, the loading pump can automatically stop running. The present invention can ensure operational safety and realize self-service loading. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 It is a schematic structural diagram of an embodiment of the first aspect of the present invention;

[0031] Figure 2 This is a schematic diagram of the steps of the second aspect of the present invention.

[0032] Among them, 1. variable frequency centrifugal pump, 2. inlet valve, 3. filter, 4. check valve, 5. outlet valve, 6. reflux valve, 7. pressure transmitter, 8. emergency shut-off valve, 9. flow meter inlet valve, 10. flow meter inlet pressure gauge, 11. mass flow meter, 12. three-stage regulating valve, 13. throttle valve, 14. oil filling valve, 15. crane pipe, 16. centrifugal pump outlet pressure gauge. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] The embodiment of the present invention discloses a variable frequency throttling combined regulation loading system for an oil depot, referring to Figure 1 As shown, it includes a pumping system, a main oil supply pipeline, and a branch loading pipeline. The pumping system is connected to the main oil supply pipeline, and the main oil supply pipeline is also connected to at least two branch loading pipelines.

[0035] The main oil supply pipeline includes an inlet valve 2, an outlet valve 5, and a pressure transmitter 7. The inlet valve 2 is arranged at the front end of the pumping system, and the pressure transmitter 7 is arranged at the rear end of the pumping system. The outlet valve 5 is arranged at the rear end of the pressure transmitter 7. The inlet valve 2 and the outlet valve 5 are used to control the on-off state of the pumping system, and play a role in controlling and protecting the pumping system. In terms of connection, the pressure transmitter 7 is also electrically connected to the pumping system, and is connected to the frequency converter of the pumping system through the pressure transmitter 7, so that the pressure signal of the main oil supply pipeline of the loading system is transmitted to the pumping system in real time. The variable frequency centrifugal pump of the pumping system adjusts the working speed according to the pressure signal, thereby realizing variable frequency control of the loading flow.

[0036] The branch loading pipeline includes a mass flow meter 11, a three-stage regulating valve 12, an oil filling valve 14, and a crane pipe 15. The front end of the mass flow meter 11 is connected to the main oil supply pipeline, and the rear end of the mass flow meter 11 is connected in sequence with the three-stage regulating valve 12, the oil filling valve 14, and the crane pipe 15. During the loading operation, the loading flow of the branch loading pipeline is adjusted by the three-stage regulating valve 12, and the flow of the branch loading pipeline can be monitored in real time by the mass flow meter 11. The three-stage regulating valve 12 serves as a control valve in the loading process, and its small flow valve position can ensure a safe small flow at the beginning and end of the loading operation. The on-off of the crane pipe 1 in the branch loading pipeline is controlled by the oil filling valve 14. During the operation, the operator only needs to control the on-off of the oil filling valve 14 to control the loading operation of the branch loading pipeline. The function of the crane pipe 15 is to connect the oil filling pipeline and the tank truck together to ensure the safety of the operation.

[0037] Furthermore, the pumping system of the present invention comprises a variable frequency centrifugal pump 1, a filter 3, a centrifugal pump outlet pressure gauge 16, and a check valve 4. The filter 3 is arranged at the inlet end of the variable frequency centrifugal pump 1 to prevent debris from entering the pump and causing damage to the equipment. The outlet end of the variable frequency centrifugal pump 1 is also connected in sequence with a centrifugal pump outlet pressure gauge 16 and a check valve 4. The centrifugal pump outlet pressure gauge 16 is used to monitor whether the pressure during loading operation exceeds the safety range, and the check valve 4 prevents oil from flowing back to damage the centrifugal pump outlet pressure gauge 16 and the variable frequency centrifugal pump 1.

[0038] Furthermore, the main oil supply pipeline also includes an emergency shut-off valve 8, which is located between the outlet valve 5 and the branch loading pipeline. In an emergency, the main oil supply pipeline can be cut off to reduce losses caused by accidents. In order to further improve the safety of the present invention, a bypass pipeline is also provided between the end of the inlet valve 2 of the main oil supply pipeline and the front end of the outlet valve 5. A reflux valve 6 is provided on the bypass pipeline. The reflux valve 6 can be used for flow regulation or as a bypass pipe of the variable frequency centrifugal pump 1 when special needs arise.

[0039] Furthermore, the branch loading pipeline also includes a throttle valve 13, which is arranged between the three-stage regulating valve 12 and the oil filling valve 14. The throttle valve 13 is used to adjust the resistance coefficient of the pipeline to ensure that the flow rate does not exceed the flow rate during loading and the flow rate change range is relatively small. The oil filling valve 14 is opened when the oil is delivered, and is closed after the oil delivery is completed to cut off the material flow. The branch loading pipeline also includes a flow meter inlet pressure gauge 10 and a flow meter inlet valve 9. The flow meter inlet pressure gauge 10 is located at the front end of the mass flow meter 11. The flow meter inlet valve 9 is located at the front end of the flow meter inlet pressure gauge 10. The flow meter inlet valve 9 is connected to the main oil supply pipeline. The flow meter inlet valve 9 is used to isolate the mass flow meter 11 during maintenance, and the flow meter inlet pressure gauge 10 is used to observe the liquid pressure to meet the working conditions of the mass flow meter 11.

[0040] The present invention adopts a three-stage regulating valve 12 to control the loading flow rate, which can switch the initial flow rate and the loading flow rate, so as to achieve free switching of the loading state and realize throttling regulation. A throttle valve 13 is set in each branch loading pipeline to adjust the resistance coefficient in the pipeline. The preset opening of the throttle valve 13 can ensure that the oil flow rate does not exceed the maximum flow limit of the loading operation under the working condition of the variable frequency centrifugal pump 1, ensure that the instantaneous flow rate does not exceed the standard during loading, and ensure the safety of the loading operation. Through the joint regulation of the three-stage regulating valve 12 and the throttle valve 13, the flow regulation of each branch loading pipeline can be achieved. Since the pipeline length, instrument performance, and loading conditions of each branch loading pipeline are different, the joint control and regulation of the three-stage regulating valve 12 and the throttle valve 13 can be adjusted according to the characteristics of each branch loading pipeline to ensure that it does not exceed the limit.

[0041] A pressure transmitter 7 is arranged on the main oil supply pipeline. When the flow of each branch loading pipeline changes, the flow of the main oil supply pipeline will be affected in real time. At this time, the pressure transmitter 7 transmits the real-time pressure data of the main oil supply pipeline to the frequency converter of the pumping system, and controls the working state of the variable frequency centrifugal pump 1 by the frequency converter to realize the flow regulation of the whole system.

[0042] The present invention realizes automatic regulation of system flow through combined frequency conversion regulation and throttling regulation, and utilizes the characteristics of the three-stage regulating valve 12. The state of each valve can also be controlled by PLC or industrial computer. During the loading operation, the loading operator only needs to open the valves in sequence, and the flow during the oil loading process is automatically controlled by the system; after the delivery is completed, only the valve needs to be closed, and the system automatically adjusts the output. After the last car is loaded, the loading pump can automatically stop running. The present invention can ensure the safety of the operation, and can realize self-service loading.

[0043] The present invention also discloses a method for controlling a variable frequency throttling combined regulation loading system of an oil depot, referring to Figure 2 As shown;

[0044] Step 1: Set the inverter target value of the variable frequency centrifugal pump 1 to the maximum, fully open all valves of the main oil supply pipeline and each branch loading pipeline, and adjust the opening of all valves to the maximum. Control the loading flow rate to the upper limit of 4.5m / s by adjusting the opening of the throttle valve 13, and record the opening of each throttle valve as the maximum opening during the loading operation. This step is to adjust the opening of the valves in the system to the maximum under the normal working conditions of the variable frequency centrifugal pump 1, and adjust the opening of each throttle valve 13 on this basis, and adjust the resistance coefficient of the system pipeline within a suitable range, so as to limit the maximum flow rate of the system to no more than 4.5m / s, and ensure safety during operation.

[0045] Step 2, record the pressure value of the centrifugal pump outlet pressure gauge 16 when the loading flow rate is at the upper limit, and set the pressure value as the parameter value of the frequency converter of the variable frequency centrifugal pump 1. Based on step 1, the pressure value of the centrifugal pump outlet pressure gauge 16 is fed back to the variable frequency centrifugal pump 1 as calibration data. When the pressure value fluctuates, the pressure in the entire system is adjusted by the variable frequency centrifugal pump 1 to correct the pressure to the calibration value.

[0046] Step three, load each branch loading pipeline separately, and further close the throttle valve 13 so that the loading flow rate is not greater than the upper limit of 4.5m / s, so as to further limit the loading flow rate when a single loading position works alone, ensuring that the upper limit of the loading flow rate does not exceed 4.5m / s under any circumstances.

[0047] Step 4: Adjust the small flow opening of the three-stage regulating valve 12 to control the loading flow rate to be less than the safety value of 1m / s. Based on step 3, by adjusting the three-stage regulating valve 12 in step 4, the flow rate at the beginning and end of the loading operation can be controlled within the required value. So far, the flow rate limitation at the beginning, end and during the loading operation is realized to ensure the safety of the loading operation.

[0048] Step 5: In the initial stage of loading, the three-stage regulating valve 12 is controlled to have a small flow opening, and the loading flow is less than the safety value of 1m / s. When the liquid level is above the crane pipe 15, the opening of the three-stage regulating valve 12 is controlled to make the loading flow not greater than the upper limit of the loading flow, 4.5m / s. When the end is near, the three-stage regulating valve 12 is controlled to have a small flow opening, and the loading flow is less than the safety value of 1m / s. Finally, the oil filling valve 14 in the branch loading pipeline is closed to realize the control of single-channel loading. At this time, since the oil filling valve 14 of a certain route is closed, the pressure of the main oil supply pipeline of the system is bound to change, causing changes in the pressure, flow rate, and flow of other branch loading pipelines. This change will be reflected in real time on the pressure transmitter 7, and the pressure transmitter 7 will feed back the pressure fluctuation to the variable frequency centrifugal pump 1, and adjust the pressure of the entire system through the output of the variable frequency centrifugal pump 1, thereby realizing the variable frequency regulation of the loading operation.

[0049] On this basis, step one also includes a pressure calibration step for the mass flow meter 11. This step is to ensure that the debugged loading flow, pressure, flow rate and other parameters meet the working requirements of the mass flow meter 11. The specific parameter settings depend on the selected mass flow meter 11. When the loading flow reaches the upper limit of 4.5m / s, verify the value of the flow meter inlet pressure gauge 10. If the value is greater than the working value of the mass flow meter 11, adjust the throttle valve 13 to make the value of the flow meter inlet pressure gauge 10 meet the working value. At this time, it is necessary to update the maximum opening of the throttle valve 13 and keep records to avoid danger caused by excessive flow during loading.

[0050] Step three also includes locking the opening of the throttle valve 13, which is achieved by removing the handle or handwheel of the throttle valve 13. The opening of the throttle valve 13 determines the upper limit of the flow value of the loading system. Locking the throttle valve 13 can prevent workers from operating it incorrectly and avoid safety hazards caused by human operation.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for adjusting a loading system of an oil depot by combining variable frequency throttling and regulation, characterized in that: The oil depot variable frequency throttling combined regulation loading system comprises a pumping system, a main oil supply pipeline, and a branch loading pipeline. The pumping system is connected to the main oil supply pipeline, and the main oil supply pipeline is also connected to at least two branch loading pipelines respectively. The main oil supply pipeline includes an inlet valve, an outlet valve, and a pressure transmitter. The inlet valve is arranged at the front end of the pumping system, the pressure transmitter is arranged at the rear end of the pumping system, the outlet valve is arranged at the rear end of the pressure transmitter, and the pressure transmitter is electrically connected to the pumping system; The branch loading pipeline includes a mass flow meter, a three-stage regulating valve, an oil filling valve, and a lifting pipe. The front end of the mass flow meter is connected to the main oil supply pipeline, and the rear end of the mass flow meter is connected to the three-stage regulating valve, the oil filling valve, and the lifting pipe in sequence; The branch loading pipeline further includes a throttle valve, which is arranged between the three-stage regulating valve and the oil loading valve. Through the joint regulation of the three-stage regulating valve and the throttle valve, the flow of the main oil supply pipeline and the branch loading pipeline is regulated; The pumping system comprises a variable frequency centrifugal pump, a filter, a centrifugal pump outlet pressure gauge, and a check valve. The filter is arranged at the inlet end of the variable frequency centrifugal pump, and the outlet end of the variable frequency centrifugal pump is also connected to the centrifugal pump outlet pressure gauge and the check valve in sequence. The branch loading pipeline also includes a flow meter inlet pressure gauge and a flow meter inlet valve, wherein the flow meter inlet pressure gauge is located at the front end of the mass flow meter, the flow meter inlet valve is located at the front end of the flow meter inlet pressure gauge, and the flow meter inlet valve is connected to the main oil supply pipeline; The adjustment method of the oil depot variable frequency throttling combined adjustment loading system includes: Step 1: Set the inverter target value of the variable frequency centrifugal pump to the maximum, fully open all valves of the main oil supply pipeline and each branch loading pipeline, and control the loading flow rate to reach the upper limit of 4.5m / s by adjusting the opening of the throttle valve, and record the opening of each throttle valve as the maximum opening at this time; pressure calibration of the mass flow meter, when the loading flow rate reaches the upper limit of 4.5m / s, verify the value of the flow meter inlet pressure gauge, if the value is greater than the working value of the mass flow meter, reduce the throttle valve, make the value of the flow meter inlet pressure gauge meet the working value, and update the maximum opening of the throttle valve; Step 2, recording the pressure value of the variable frequency centrifugal pump outlet pressure gauge when the loading flow rate is at an upper limit, and setting the pressure value as a parameter value of the frequency converter of the variable frequency centrifugal pump; Step 3, each branch loading pipeline is loaded separately, and the throttle valve is further closed to make the loading flow rate not greater than the upper limit of the loading flow rate of 4.5m / s; Step 4, adjusting the small flow opening of the three-stage regulating valve to control the loading flow to be less than the safety value of 1m / s; Step 5: In the initial stage of loading, the three-stage regulating valve is controlled to have a small flow opening, and the loading flow is less than the safety value of 1m / s. When the liquid level is above the crane pipe, the opening of the three-stage regulating valve is controlled to make the loading flow not greater than the upper limit of 4.5m / s.

2. The adjustment method of the oil depot variable frequency throttling combined adjustment loading system according to claim 1 is characterized in that: The main oil supply pipeline also includes an emergency shut-off valve, which is located between the outlet valve and the branch loading pipeline.

3. The adjustment method of the oil depot variable frequency throttling combined adjustment loading system according to claim 1 is characterized in that: A bypass pipeline is also provided between the end of the inlet valve of the main oil supply pipeline and the front end of the outlet valve, and a reflux valve is provided on the bypass pipeline.

4. The adjustment method of the oil depot variable frequency throttling combined adjustment loading system according to claim 1 is characterized in that: The step three also includes locking the throttle valve opening.

5. The adjustment method of the oil depot variable frequency throttling combined adjustment loading system according to claim 4 is characterized in that: Locking the throttle valve is achieved by removing the handle or handwheel of the throttle valve.

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