A linkage method for preventing water hammer and slurry hammer in long-distance and large-drop slurry pipelines

Abstract

The present invention discloses a method for preventing water hammer and slurry hammer in a long-distance, extremely high-drop slurry pipeline. The method measures the slurry inlet pressure P1 on the slurry pipeline through a pressure measuring system A, and feeds the slurry inlet pressure P1 back to an energy storage type surge tank. The energy storage type surge tank regulates the pressure in the slurry pipeline so that the slurry pipeline is always full. Pressure measuring systems B, C, and D are sequentially arranged on the slurry pipeline between the energy storage type surge tank and the energy dissipation station. The data measured by pressure measuring systems B, C, and D are fed back to a control terminal. The control terminal adjusts the type and number of energy dissipation orifice plates in the energy dissipation station based on the pressure measuring data. The control terminal uses the pressure measuring data to adjust the type and number of energy dissipation orifice plates in the energy dissipation station to avoid problems that endanger pipeline safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline transmission protection, and relates to a method for preventing water hammer and slurry hammer in a long-distance, extremely high-drop slurry pipeline. Background Art

[0002] When transporting water-coal slurry over long distances, due to the long distance and large resistance, multi-stage pumps are generally connected in series. When the pump is started or stopped, the slurry speed may change due to changes in the speed of a certain pump, or other power machinery failures may cause the slurry to impact the site and hit the pipeline.

[0003] During long-distance pipeline transportation, there is a risk of water hammer and slurry hammer when water pushes slurry or slurry pushes water. Once water hammer or slurry hammers the pipeline, it will cause pipeline damage and slurry leakage, forming soft blockages at the valleys and vacuum hard blockages at the peaks, causing immeasurable losses.

[0004] At present, the energy storage pressure regulating tank and energy dissipation station are used separately, which makes it difficult to control the terminal for emergency handling. The number of regulating orifice plates at the terminal is currently adjusted according to the inlet pressure. There is often an excessive or insufficient number of energy dissipation orifice plates in use, making it difficult to achieve precise control. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preventing water hammer and slurry hammer linkage in long-distance and large-drop slurry pipelines, and to use a control terminal to adjust the type and number of energy dissipation orifice plates in the energy dissipation station according to pressure measurement data to avoid problems that endanger pipeline safety.

[0006] The technical solution adopted by the present invention is a method for preventing water hammer and slurry hammer in a long-distance and extremely large-drop slurry pipeline. The slurry inlet pressure P1 on the slurry pipeline is measured by the pressure measuring system A, and the slurry inlet pressure P1 is fed back to the energy storage type pressure regulating tank. The pressure in the slurry pipeline is adjusted by the energy storage type pressure regulating tank so that the slurry pipeline is always full. The pressure measuring system B, the pressure measuring system C and the pressure measuring system D are arranged in sequence on the slurry pipeline between the energy storage type pressure regulating tank and the energy dissipation station. The data measured by the pressure measuring system B, the pressure measuring system C and the pressure measuring system D are fed back to the control terminal. The control terminal adjusts the type and number of energy dissipation orifice plates in the energy dissipation station according to the pressure measuring data.

[0007] The present invention is also characterized in that:

[0008] The accumulator-type pressure regulating tank ensures that the incoming slurry pipeline is always full by filling or discharging slurry from the bladder.

[0009] Pressure measuring system B, pressure measuring system C and pressure measuring system D are distributed at different heights and mileages of the slurry pipeline to carry out pressure measurement in stages.

[0010] The total orifice plate resistance coefficient K in the energy dissipation station is shown in the following formula:

[0011] K=0.093(ΔP / γ) / (Q 2 ) (1);

[0012] in, is the coal slurry density, kg / m 3 ; Q is the flow rate, m 3 / s; ΔP is the pressure difference, Pa;

[0013] The pressure measured by pressure measuring system B is P2, the pressure measured by pressure measuring system C is P3, and the pressure measured by pressure measuring system D is P4. ΔP is the difference between the maximum and minimum pressure values ​​among P2, P3, and P4.

[0014] The relationship between the total orifice plate resistance coefficient K and the high-resistance orifice plate resistance coefficient K2, the medium-resistance orifice plate resistance coefficient K3, the low-resistance orifice plate resistance coefficient K4 and the fixed orifice plate resistance coefficient K1 in the energy dissipation station is shown in the following formula (2):

[0015] K=n1*K1+n2*K2+n3*K3+n4*K4 (2);

[0016] Among them, n1 represents the number of fixed orifice plates in use, n2 represents the number of high-resistance orifice plates in use, n3 represents the number of medium-resistance orifice plates in use, and n4 represents the number of low-resistance orifice plates in use.

[0017] When the pressure difference ΔP is less than 0.5 MPa, only the low-resistance orifice plates are used. Combining formula (1) and formula (2), the value of n4 is calculated, that is, the number of low-resistance orifice plates used is obtained;

[0018] When the pressure difference ΔP is between 0.5MPa and 2MPa, only the medium resistance orifice plate is put into use. Combining formula (1) and formula (2), the value of n3 is calculated, that is, the number of medium resistance orifice plates put into use is obtained;

[0019] When the pressure difference ΔP is between 2MPa and 3MPa, only the fixed orifice plate is used. Combining formula (1) and formula (2), the value of n1 is calculated, that is, the number of fixed orifice plates used is obtained;

[0020] When the pressure difference ΔP is greater than 3 MPa, only the high-resistance orifice plate is used. Combining formula (1) and formula (2), the value of n2 is calculated, that is, the number of fixed orifice plates used is obtained.

[0021] The beneficial effect of the present invention is that the present invention transmits through the SCADA system and issues adjustment instructions through the control terminal 6. When the slurry passes through the pressure measuring system A1, the control terminal 6 adjusts the pressure of the energy storage type pressure regulating tank 2 according to the pressure data P1 of the pressure measuring system A1. The working principle of the energy storage type pressure regulating tank 2 is to use the method of filling the slurry in the bag and filling the tank with nitrogen. When the pipeline pressure is high, the bag is filled with slurry (when the pressure in the pipeline is greater than 13MPa), and when the pipeline pressure is negative (the pressure in the pipeline is less than 10MPa), the slurry is discharged from the bag. This effectively prevents slurry impact and slurry gasification, balances the pipeline pressure, and ensures the smooth operation of the slurry in the pipe. The present invention interlocks the energy storage type pressure regulating tank and the energy dissipation orifice plate to form a double insurance, accurately put the number of orifice plates into use, and avoids the use of excess orifice plates or insufficient energy dissipation capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the linkage device used in the method for preventing water hammer and slurry hammer in a long-distance and large-drop slurry pipeline of the present invention.

[0023] In the figure, 1. Pressure measuring system A, 2. Energy storage type pressure regulating tank, 3. Pressure measuring system B, 4. Pressure measuring system C, 5. Pressure measuring system D, 6. Control terminal, 7. Energy dissipation station. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The invention discloses a method for preventing water hammer and slurry hammer in a long-distance and large-drop slurry pipeline. Figure 1The linkage device shown is configured by installing an energy storage type surge tank 2 at a high point or a crossing point, and an energy dissipation station 7 at a control terminal 6. Based on the existing supervisory control and data acquisition (SCADA) system, the pressure, flow and other data are transmitted, thereby combining the energy storage type surge tank 2 and the energy dissipation station 7. The slurry inlet pipeline of the energy storage type surge tank 2 is provided with a pressure measuring system A1, which measures the pressure data as P1. After the slurry inlet pressure of the energy storage type surge tank 2 is tested by the pressure measuring system A1, the pressure is fed back to the energy storage type surge tank 2. The energy storage type surge tank 2 will then operate to determine whether the slurry is being filled or discharged from the bladder, so as to ensure that the pipeline is always full, thereby avoiding negative pressure, water hammer and slurry hammer, which may endanger the pipeline safety. After the energy storage pressure regulating tank 2 reacts and adjusts, the pressure measuring system B3 (test data is P2) is arranged 13 kilometers away from the energy storage pressure regulating tank 2, the pressure measuring system C4 (test data P3) is arranged 23 kilometers away from the pressure measuring system B3, and the pressure measuring system D5 (test data P4) is 23 kilometers away from the pressure measuring system C4. Then it is connected to the energy dissipation station 7, and the test data is transmitted to the control terminal 6 through the system. The control terminal 6 adjusts the type and number of energy dissipation orifice plates in the energy dissipation station 7 according to the pressure measuring data to avoid the potential energy generated by the large drop from causing damage to the terminal equipment and to ensure the safe operation of the pipeline. The energy dissipation station 7 is composed of high-resistance orifice plates, medium-resistance orifice plates, low-resistance orifice plates and fixed orifice plates. The type and number of orifice plates are determined according to the transmission pressure. The waste slurry generated in the energy storage pressure regulating tank 2 is discharged into the waste slurry pool.

[0026] Pressure measuring system A1 is located at K486, with an elevation of 1149m; energy storage pressure regulating tank 2 is located at K507, with an elevation of 1482m; pressure measuring system B3 is located at K520, with an elevation of 880m; pressure measuring system C4 is located at K543, with an elevation of 310m; pressure measuring system 45 is located at K566, with an elevation of 706m; energy dissipation station 7 is located at K590, with an elevation of 360m.

[0027] Pressure measurement systems A1, B3, C4 and D5 all use 3151SG pressure transmitters with a pressure detection range of 0-15MPa.

[0028] When the pressure value of pressure measurement system A1 is low, slurry is squeezed out of the bladder to replenish the slurry volume. When the pipeline pressure is high, slurry is introduced into the bladder through the pressure difference. Pressure measurement systems B3, C4, and D5 are located at different heights and distances. Through staged pressure measurement, control terminal 6 controls the type and number of orifice plates in energy dissipation station 7 to ensure safe and stable operation of long-distance pipelines. When the pressure passes through pressure measurement system D5, control terminal 6 receives the data, calculates the potential energy based on the pressure, calculates the orifice plate resistance coefficient, and then determines the type and number of orifice plates to be used.

[0029] The total orifice plate coefficient of energy dissipation station 7 is shown in the following formula (1):

[0030] K=0.093(ΔP / γ) / (Q 2 ) (1);

[0031] K is the resistance coefficient of the orifice plate in the energy dissipation station 7;

[0032] is the coal slurry density, kg / m 3 ;

[0033] Q is the flow rate, m 3 / s;

[0034] ΔP is the pressure difference, Pa;

[0035] The pressure measured by the pressure measuring system B3 is P2, the pressure measured by the pressure measuring system C4 is P3, and the pressure measured by the pressure measuring system D5 is P4. ΔP is the difference between the maximum and minimum pressure values ​​among P2, P3, and P4.

[0036] The total orifice plate resistance coefficient K in the energy dissipation station 7 is categorized into high-resistance orifice plates, medium-resistance orifice plates, low-resistance orifice plates, and fixed orifice plates. The fixed orifice plate resistance coefficient is K1 (known), the high-resistance orifice plate resistance coefficient is K2 (known), the medium-resistance orifice plate resistance coefficient is K3 (known), and the low-resistance orifice plate resistance coefficient is K4 (known). The relationship between the total orifice plate resistance system K and the fixed orifice plate resistance system K1, the high-resistance orifice plate resistance coefficient K2, the medium-resistance orifice plate resistance coefficient K3, and the low-resistance orifice plate resistance coefficient K4 is as follows:

[0037] K=n1*K1+n2*K2+n3*K3+n4*K4 (2);

[0038] Among them, n1 represents the number of fixed orifice plates in use, n2 represents the number of high-resistance orifice plates in use, n3 represents the number of medium-resistance orifice plates in use, and n4 represents the number of low-resistance orifice plates in use.

[0039] When the pressure difference ΔP is less than 0.5 MPa, only the low-resistance orifice plates are used. Then, by combining formula (1) and formula (2), the value of n4 is calculated, that is, the number of low-resistance orifice plates used is obtained.

[0040] When the pressure difference ΔP is between 0.5MPa and 2MPa, only the medium resistance orifice plate is put into use. Then, by combining formula (1) and formula (2), the value of n3 is calculated, that is, the number of medium resistance orifice plates put into use is obtained.

[0041] When the pressure difference ΔP is between 2MPa and 3MPa, only the fixed orifice plate is used. Then, by combining formula (1) and formula (2), the value of n1 is calculated, which is the number of fixed orifice plates used.

[0042] When the pressure difference ΔP is greater than 3MPa, only the high-resistance orifice plate is used. Then, by combining formula (1) and formula (2), the value of n2 is calculated, which is the number of fixed orifice plates used.

[0043] The working principle of the method for preventing water hammer and slurry hammer linkage in long-distance and large-drop slurry pipelines of the present invention is that when the drop of the coal slurry in the pipeline is large, the pipeline is prone to full flow. At this time, the potential energy of the slurry is much higher than the pipeline resistance, and slurry hammer and water hammer pipeline phenomena will occur. At this time, the control terminal 6 needs to adjust the type and number of energy dissipation orifice plates in the energy dissipation station. The orifice plates are put into use to eliminate excess potential energy by reducing the aperture, thereby eliminating slurry hammer and water hammer phenomena.

[0044] Example 1

[0045] A method for preventing water hammer and slurry hammer linkage in a long-distance, extremely high-drop slurry pipeline is provided. The slurry inlet pressure P1 on the slurry pipeline is measured by the pressure measuring system A1, and the slurry inlet pressure P1 is fed back to the energy storage type surge tank 2. The pressure in the slurry pipeline is adjusted by the energy storage type surge tank 2 so that the slurry pipeline is always full. The pressure measuring systems B3, C4 and D5 are arranged in sequence on the slurry pipeline between the energy storage type surge tank 2 and the energy dissipation station 7. The data measured by the pressure measuring systems B3, C4 and D5 are fed back to the control terminal 6. The control terminal 6 adjusts the type and number of energy dissipation orifice plates in the energy dissipation station 7 according to the pressure measuring data.

[0046] Example 2

[0047] On the basis of Example 1, the energy storage type pressure regulating tank 2 ensures that the slurry pipeline is always full by filling or discharging slurry in the bladder.

[0048] Example 3

[0049] On the basis of Example 1, the pressure measuring systems B3, C4 and D5 are distributed at different heights and mileages of the slurry pipeline to perform pressure measurement in stages.

Claims

1. A method for preventing water hammer and slurry hammer in a long-distance and large-drop slurry pipeline, characterized by: The slurry inlet pressure P1 on the slurry inlet pipeline is measured by the pressure measuring system A (1), and the slurry inlet pressure P1 is fed back to the energy storage type pressure regulating tank (2). The pressure in the slurry inlet pipeline is adjusted by the energy storage type pressure regulating tank (2) so that the slurry inlet pipeline is always full. The pressure measuring system B (3), the pressure measuring system C (4) and the pressure measuring system D (5) are arranged in sequence on the slurry inlet pipeline between the energy storage type pressure regulating tank (2) and the energy dissipation station (7). The data measured by the pressure measuring system B (3), the pressure measuring system C (4) and the pressure measuring system D (5) are fed back to the control terminal (6). The control terminal (6) adjusts the type and number of the energy dissipation orifice plates in the energy dissipation station (7) according to the pressure measuring data. The total orifice plate resistance coefficient K in the energy dissipation station (7) is shown in the following formula (1): （1）； in, is the coal slurry density, kg / m 3 ; Q is the flow rate, m 3 / s; is the pressure difference, Pa; The pressure measured by pressure measuring system B (3) is P2, the pressure measured by pressure measuring system C (4) is P3, and the pressure measured by pressure measuring system D (5) is P4. It is the difference between the maximum pressure value and the minimum pressure value among P2, P3, and P4; The relationship between the total orifice plate resistance coefficient K and the high resistance orifice plate resistance coefficient K2, medium resistance orifice plate resistance coefficient K3, low resistance orifice plate resistance coefficient K4 and fixed orifice plate resistance coefficient K1 of the energy dissipation station (7) is shown in the following formula (2): （2）； Wherein, n1 represents the number of fixed orifice plates in use, n2 represents the number of high-resistance orifice plates in use, n3 represents the number of medium-resistance orifice plates in use, and n4 represents the number of low-resistance orifice plates in use; When the pressure difference When the pressure is less than 0.5 MPa, only low-resistance orifice plates are used. Combining formula (1) and formula (2), the value of n4 is obtained, that is, the number of low-resistance orifice plates used is obtained; When the pressure difference When the pressure is between 0.5MPa and 2MPa, only medium-resistance orifice plates are used. Combining formula (1) and formula (2), the value of n3 is obtained, that is, the number of medium-resistance orifice plates used is obtained; When the pressure difference When the pressure is between 2MPa and 3MPa, only fixed orifice plates are used. Combining formula (1) and formula (2), the value of n1 is obtained, which is the number of fixed orifice plates used. When the pressure difference When the pressure is greater than 3 MPa, only high-resistance orifice plates are used. Combining formula (1) and formula (2), the value of n2 is calculated, that is, the number of fixed orifice plates used is obtained.

2. The method for preventing water hammer and slurry hammer in a long-distance and large-drop slurry pipeline according to claim 1 is characterized by: The energy storage type pressure regulating tank (2) ensures that the slurry incoming pipeline is always full by filling the slurry in the bladder or discharging the slurry in the bladder.

3. The method for preventing water hammer and slurry hammer in a long-distance and large-drop slurry pipeline according to claim 1 is characterized in that: The pressure measuring system B (3), the pressure measuring system C (4), and the pressure measuring system D (5) are distributed at different heights and different mileages of the slurry pipeline to perform pressure measurement in stages.

Images