Method for monitoring and controlling power of dredge pump during long-distance complex slurry conveying of trailing suction dredger

Abstract

The invention discloses a dredge pump power monitoring and controlling method during long-distance complex slurry conveying of a trailing suction dredger, which comprises the following steps of: firstly, monitoring parameters, mounting a slurry densimeter, a pressure transmitter and a flow meter at an outlet of a dredge pump pipeline, collecting the slurry density rho, the pump pressure P and the flow velocity v in real time, measuring the density by the slurry densimeter; the pressure transmitter obtains pressure data, and the flow meter monitors flow. Secondly, pipe blockage risk judgment and power adjustment are carried out, judgment is carried out through two modes, and in the first mode, flow length related pipeline loss judgment is calculated based on the real-time density rho and the flow velocity v in combination with the collection time interval; in the second mode, the total pipeline resistance is calculated through a fitting formula based on the density rho and the flow velocity v under the rated flow and compared with the pump pressure P for judgment. The power of the dredge pump is increased immediately when the pipe blocking risk is judged in any mode; collecting data every 30 minutes after the self-dredge pump is started for 30 minutes, and adjusting the constant A according to the relationship between the density and the viscosity when the accumulated flow length reaches a specific condition; the method can ensure smooth conveying of the slurry and improve the construction efficiency and the equipment safety.

Description

Technical Field

[0001] This invention belongs to the field of mud transport monitoring technology for trailing suction hopper dredgers, and particularly relates to a method for monitoring and controlling the power of mud pumps during long-distance and complex mud transport by trailing suction hopper dredgers. Background Technology

[0002] As an important piece of dredging equipment, the trailing suction hopper dredger's core operational process involves using a mud pump to transport dredged mud over long distances via pipelines to a designated area. In this complex process, transport efficiency is not determined by a single factor but is influenced by a combination of parameters, including mud density, flow rate, and pressure. The change in mud density is closely related to pipeline resistance; higher density generally results in higher pipeline resistance. Flow rate and pressure together determine the stability of mud transport, and a proper match between these two parameters is crucial for ensuring smooth mud delivery.

[0003] Currently, in the field of power control for trailing suction hopper dredgers' mud pumps, the following two methods are mainly used:

[0004] Fixed threshold control: This method pre-sets fixed power levels, and the mud pump operates at these preset fixed power levels throughout the mud transport process. However, this control method has significant limitations; it cannot flexibly adjust according to the dynamic changes in mud characteristics. In actual dredging operations, the density, flow rate, and other characteristics of the mud constantly change with variations in the geological conditions of the excavation area, the excavation depth, and other factors. Fixed threshold control is clearly unsuitable for such complex working conditions.

[0005] Single-parameter feedback control: This method adjusts the pump power based on only one parameter, such as pressure or flow rate. While it can respond to changes in a single parameter to some extent, it ignores the coupling effect between multiple parameters during mud transport. In reality, parameters such as mud density, flow rate, and pressure influence and constrain each other. Adjusting the power based on only a single parameter makes it difficult to achieve precise control of the pump power.

[0006] Analysis of existing technology defects

[0007] Lack of Monitoring Dimensions: Existing mud pump power control methods suffer from severe deficiencies in monitoring, lacking synchronous real-time monitoring of key parameters such as mud density, flow rate, and pressure. This makes it difficult for operators to comprehensively and promptly grasp the status information during mud transportation, and to detect early signs of pipe blockage. Once pipe blockage occurs, it not only affects the progress of dredging operations but may also lead to equipment damage and increased maintenance costs.

[0008] Lagging risk assessment: Currently, there is no established pipe blockage assessment model based on dynamic calculation of pipeline resistance. During slurry transportation, when the slurry concentration suddenly increases, the pipeline resistance increases rapidly. However, due to the lack of an effective assessment model, it is impossible to provide early warning of pipe blockage risk. Operators can only take measures after pipe blockage occurs, by which time significant losses have often already occurred.

[0009] Insufficient adaptability: Existing power adjustment mechanisms do not fully consider the time-varying characteristics of mud. In actual operations, the characteristics of mud constantly change with time and operating conditions, and existing power adjustment methods cannot adapt to these changes in a timely manner. This easily leads to two types of failures: First, when mud characteristics change, such as increased density or flow rate, insufficient mud pump power can cause pipeline blockage, leading to equipment damage; second, excessive mud pump power will result in energy waste and increased operating costs.

[0010] In summary, existing methods for controlling the power of mud pumps in trailing suction hopper dredgers have many shortcomings in terms of monitoring, risk prediction, and adaptability, and cannot meet the needs of long-distance and complex mud transportation conditions. There is an urgent need for a more scientific and effective method for monitoring and controlling the power of mud pumps. Summary of the Invention

[0011] To address the problems existing in the prior art, this invention provides a method for monitoring and controlling the power of the mud pump during long-distance and complex mud transportation in a trailing suction hopper dredger. By monitoring key parameters such as mud density, pump pressure, and flow rate in real time, and judging the risk of pipe blockage based on the monitoring data, the mud pump power is adjusted in a timely manner to ensure smooth mud transportation and improve the construction efficiency and equipment safety of the trailing suction hopper dredger.

[0012] This invention is implemented as follows: a method for monitoring and controlling the power of a mud pump during long-distance complex mud transport by a dredging vessel, comprising the following steps:

[0013] (1) Parameter monitoring: Install a mud density meter, a pressure transmitter, and an electromagnetic flow meter or sonar flow meter at the outlet of the mud pump pipeline to collect mud density ρ, pump pressure P, and flow velocity v in real time; the mud density meter is used to measure the density change of mud; the pressure transmitter is used to acquire the pressure data inside the pump in real time; the electromagnetic flow meter or sonar flow meter is used to accurately monitor the flow information of mud.

[0014] (2) Pipe blockage risk assessment and power adjustment: Assessment is conducted using any of the following modes:

[0015] Mode 1: Based on real-time collected density ρ and flow velocity v, and combined with the collection time interval t, calculate the flow length L1 = v × t, and obtain the pipeline loss h along the length L1; if Limited, determined to be without risk of pipe blockage; if If it is limited, it is determined that there is a risk of pipe blockage;

[0016] Mode 2: Based on the density ρ and the flow velocity v at the rated flow rate, calculate the total pipeline resistance h through the mud pipeline resistance formula; if h < P, it is determined that there is no risk of pipe blockage; if h > P, it is determined that there is a risk of pipe blockage;

[0017] (3) Execution control: When any mode determines that there is a risk of pipe blockage, immediately increase the power of the mud pump;

[0018] (4) Density dynamic correction: Starting from 30 minutes after the mud pump is started, data is collected every 30 minutes; when the cumulative flow length ∑L1 = L, if or then adjust the constant A according to the relationship between density and viscosity.

[0019] Further preferably, in Mode 1 of step (2), when increasing the power of the mud pump, synchronously control the mud flow rate not to be lower than the flow rate corresponding to the real-time collected flow velocity v.

[0020] Further preferably, in Mode 2 of step (2), when increasing the power of the mud pump, ensure that the mud flow rate reaches the rated flow rate.

[0021] Further preferably, in the density dynamic correction of step (4), the cumulative flow length ΣL1 satisfies:

[0022] where L 1i = v i × t.

[0023] Further preferably, the mud density meter is used to monitor the change of mud density in real time, and the accuracy error ≤ ±0.5%.

[0024] Further preferably, the sampling frequency of the pressure transmitter ≥ 10Hz, and the pump pressure fluctuation is monitored in real time.

[0025] Further preferably, the flow monitoring error of the electromagnetic flowmeter or sonar flowmeter ≤ ±1.5%.

[0026] The advantages and technical effects of the present invention: The present invention provides an efficient method for monitoring and controlling the power of the mud pump for the long-distance and complex mud transportation of the trailing suction dredger, bringing significant technical effects.

[0027] In terms of monitoring accuracy, by installing a mud density meter, a pressure transmitter, and an electromagnetic flowmeter or sonar flowmeter at the outlet of the mud pump pipeline, the real-time and accurate monitoring of the mud density, the pressure of the pump, and the flow rate is realized. The mud density meter can accurately capture the change of mud density, the pressure transmitter can provide real-time feedback on the pressure inside the pump, and the flowmeter can accurately monitor the flow rate information, providing a reliable data basis for subsequent risk judgment and power adjustment.

[0028] In terms of risk prediction capabilities, this invention possesses a multi-dimensional judgment mechanism. Based on real-time data, when an increasing trend in mud concentration is detected, the risk of pipe blockage can be promptly assessed. Based on pipeline loss calculations, by collecting parameters such as density and flow velocity, combined with pipeline length and limiting pressure, the pipeline pressure loss can be accurately determined, providing early warning of pipe blockage risk. Under rated flow conditions, pipeline resistance is calculated using a fitted formula to determine whether pipe blockage has occurred. Compared to traditional methods, this multi-dimensional judgment approach significantly improves the accuracy and timeliness of risk prediction.

[0029] In terms of power adjustment, the system can quickly and accurately adjust the mud pump power based on different pipe blockage risk assessment results. When a pipe blockage risk is detected, the mud pump power is automatically increased to improve mud conveying capacity, overcome pipeline resistance, ensure normal mud conveying, effectively avoid pipeline blockage and equipment damage caused by insufficient power, and also prevent energy waste caused by excessive power.

[0030] Furthermore, this invention incorporates a density revision mechanism to periodically adjust the mud density, making the system's judgment of mud characteristics more accurate and further improving the precision of pipe blockage risk assessment and power adjustment. Overall, this invention significantly improves the construction efficiency and equipment safety of trailing suction hopper dredgers under long-distance and complex mud transportation conditions. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] A method for monitoring and controlling the power of a mud pump during long-distance complex mud transport by a dredging vessel includes the following steps:

[0033] (1) Parameter monitoring: Install a mud density meter, a pressure transmitter, and an electromagnetic flowmeter or a sonar flowmeter at the outlet of the mud pump pipeline to collect the mud density ρ, the pump pressure P, and the flow velocity v in real time; the mud density meter is used to measure the density change of the mud; the pressure transmitter is used to obtain the pressure data inside the pump in real time; the electromagnetic flowmeter or the sonar flowmeter is used to accurately monitor the flow information of the mud; in the process of long-distance and complex mud transportation by a trailing suction hopper dredger, the mud density, the pump pressure, and the flow velocity are key parameters affecting the power of the mud pump and the transportation state. Only by accurately obtaining these parameters in real time can reliable basis be provided for subsequent judgment of pipe blockage risk and power adjustment; this step is the basis of the whole monitoring and control method. The accurate measurement of the mud density change by the mud density meter helps to understand the characteristics of the mud; the real-time acquisition of the pump pressure data by the pressure transmitter can reflect the working state of the mud pump; the accurate monitoring of the flow information by the electromagnetic flowmeter or the sonar flowmeter can master the mud transportation volume. The accurate acquisition of these parameters is the premise of subsequent accurate judgment and effective control; it solves the problem of being unable to master the key parameters in the mud transportation process in real time and avoids blind operation caused by unknown parameters; it can provide accurate data support for subsequent steps and improve the accuracy and reliability of the whole monitoring and control method.

[0034] (2) Judgment of pipe blockage risk and power adjustment: Judge through any of the following modes:

[0035] Based on the density ρ and the flow velocity v collected in real time, calculate the flow length L1 = v×t by combining the acquisition time interval t, and obtain the pipeline loss h of the L1 length; if It is specified that there is no risk of pipe blockage; if It is specified, then it is determined that there is a risk of pipe blockage;

[0036] In this mode, during the mud transportation process, the pipeline loss is closely related to parameters such as mud density and flow velocity. By calculating the flow length and the pipeline loss and comparing them with the specified pressure, it is possible to judge whether there is a risk of pipe blockage, so as to take measures in time to adjust the power of the mud pump; this mode is calculated and judged based on the data collected in real time and can quickly respond to the changes in mud characteristics; when it is judged that there is a risk of pipe blockage, increasing the power of the mud pump in time can improve the transportation capacity of the mud and reduce the possibility of pipe blockage, solve the problem of being unable to predict the pipe blockage risk in advance, and avoid equipment damage and construction interruption caused by pipe blockage; effectively improve the stability of mud transportation, reduce the occurrence of pipe blockage accidents, and ensure the smooth progress of construction. At the same time, when increasing the power of the mud pump, synchronously control the mud flow rate not to be lower than the flow rate corresponding to the flow velocity collected in real time, ensuring the continuity and stability of mud transportation;

[0037] Mode 2: Based on the density ρ and the flow velocity v under the rated flow rate, calculate the total pipeline resistance h through a fitting formula; if h < P, it is determined that there is no risk of pipe blockage; if h > P, it is determined that there is a risk of pipe blockage;

[0038] In this mode, the total pipeline resistance at rated flow is related to parameters such as slurry density. By calculating the total pipeline resistance using a fitted formula and comparing it with the limiting pressure, it is possible to determine whether there is a risk of pipe blockage at rated flow, and then adjust the slurry pump power accordingly. This mode considers the important operating condition of rated flow, ensuring normal slurry delivery at rated flow. When a risk of pipe blockage is detected, the slurry pump power is increased to ensure the slurry flow reaches the rated flow, maintaining the stability and efficiency of slurry delivery. This solves the problem of not being able to accurately determine the risk of pipe blockage at rated flow, ensuring stable operation of slurry delivery at rated flow; it also ensures the quality of slurry delivery at rated flow, improves construction efficiency, and avoids delivery obstruction due to insufficient flow.

[0039] (3) Execution control: When any mode determines that there is a risk of pipe blockage, the mud pump power is increased immediately;

[0040] To overcome pipeline resistance and prevent pipe blockage accidents, this step is a crucial link in the entire monitoring and control method, directly related to the safety and stability of mud transportation. Timely increases in mud pump power can prevent the escalation of pipe blockage accidents and reduce equipment damage and construction losses.

[0041] This solved the problem of not being able to take effective measures in a timely manner after the risk of pipe blockage was determined, thus ensuring the continuity and safety of mud transportation.

[0042] This effectively reduced the probability of pipe blockage accidents, ensured the smooth progress of construction, and improved the reliability and service life of the equipment.

[0043] (4) Density dynamic correction: Data is collected every 30 minutes starting 30 minutes after the mud pump starts; when the cumulative flow length ∑L1=L, if or The constant A is adjusted based on the relationship between density and viscosity. During mud transport, the mud density may change. By periodically collecting data and correcting the density, the system can more accurately judge the mud characteristics, improving the accuracy of pipe blockage risk assessment and power adjustment. This step adapts to the dynamic changes in mud characteristics, ensuring the accuracy and effectiveness of the monitoring and control methods. Timely correction of the density parameter as mud transport progresses ensures the system maintains accurate control over mud characteristics. This solves the problem of inaccurate monitoring and control methods due to changes in mud density, improving the system's adaptability. It also enhances the accuracy and reliability of the entire monitoring and control method, further ensuring the safety and stability of mud transport.

[0044] In a further preferred embodiment, in mode one of step (2), when the mud pump power is increased, the mud flow rate is simultaneously controlled to be no less than the flow rate corresponding to the real-time collected flow velocity v.

[0045] In a further preferred embodiment, in step (2) of mode two, when increasing the power of the mud pump, it is ensured that the mud flow rate reaches the rated flow rate.

[0046] More preferably, in the density dynamic correction of step (4), the cumulative flow length ΣL1 satisfies: Where L 1i =v i ×t.

[0047] More preferably, the mud density meter is used to monitor changes in mud density in real time, and its measurement range is adapted to mud densities of 1.1–1.5 g / cm³. 3 Accuracy ±0.01g / cm 3 This ensured the accuracy of mud density measurement, providing more reliable data support for subsequent pipe blockage risk assessment and power adjustment, and improving the overall accuracy of the method.

[0048] Further preferably, the pressure transmitter has a sampling frequency of ≥10Hz to monitor pump pressure fluctuations in real time. This real-time monitoring allows for timely detection of pressure anomalies, providing more timely information for assessing pipe blockage risks and facilitating rapid intervention to prevent blockages.

[0049] Preferably, the electromagnetic flowmeter or sonar flowmeter has a flow monitoring accuracy of ±0.05 m / s. This ensures the accuracy of flow monitoring, enabling the system to accurately determine the slurry delivery volume and providing a more precise basis for power adjustment and pipe blockage risk assessment.

[0050] This embodiment uses the slurry conveying system of a dredging vessel's in-hull pump as an example to illustrate the specific application process of the pipe blockage risk assessment and power adjustment method. The system includes a slurry conveying pipeline (5000m in length, 1000mm in diameter) and a slurry pump (rated power 15000kW, rated flow rate 15000m³ / h). 3 / h), density sensor (measuring range 0.8-2.5g / cm³) 3 Accuracy ±0.01g / cm 3 ), flow velocity sensor (measurement range 0-10m / s, accuracy ±0.05m / s), data acquisition module, control module and power regulation module.

[0051] I. System Initialization and Parameter Setting: Before the system starts, relevant parameters need to be set. For Mode 1, considering the characteristics of the long pipeline length and large pipe diameter in the dredging cabin of the dredging project, the limit value of the pipeline loss for the flow length is set to 55m. That is, when the pipeline loss h of the calculated L1 length ≤ 55m, it is determined that there is no risk of pipe blockage; when h > 55m, it is determined that there is a risk of pipe blockage. For Mode 2, considering the special nature of the conveying environment in the cabin pump, the limit value P of the total pipeline resistance is set to 65m. That is, when the calculated total pipeline resistance h < P (65m), it is determined that there is no risk of pipe blockage; when h > P (65m), it is determined that there is a risk of pipe blockage. At the same time, the threshold value of the cumulative flow length in the density dynamic correction is set to 15000m, and the limit value of the density ρ1 = 1.0g / cm 3 and ρ2 = 2.0g / cm 3 .

[0052] II. Process of Pipe Blockage Risk Judgment and Power Adjustment

[0053] (I) Application of Mode 1

[0054] The data acquisition module continuously acquires the density ρ and flow velocity v of the slurry. Considering the stability requirement of slurry transportation in the dredging project, the acquisition time interval t is set to 5s. Suppose at a certain moment, the acquired density ρ = 1.3g / cm 3 , and the flow velocity v = 4m / s. According to the flow length calculation formula L = vt, the flow length L within 5s can be obtained as L = 4×5 = 20m. Combining with the long-distance large-diameter pipeline loss calculation model in the dredging project (considering both the frictional resistance along the way and the local elbow resistance), the pipeline loss h of this L1 = 20m length is calculated as h = 50m. Since 50m ≤ 55m, according to the judgment rule of Mode 1, it is determined that there is no risk of pipe blockage at this time.

[0055] After a period of time, the data acquisition module acquires the density ρ = 1.6g / cm 3 again, and the flow velocity v = 3.5m / s. Similarly, within a 5s time interval, the flow length L = 3.5×5 = 17.5m. After calculation, the pipeline loss h of this L1 = 17.5m length is h = 58m. Because 58m > 55m, Mode 1 determines that there is a risk of pipe blockage.

[0056] (II) Application of Mode 2

[0057] The total pipeline resistance h is calculated based on the density ρ and the flow velocity v under the rated flow rate. Given that the rated flow rate of the mud pump is 15000m 3 / h, and according to the pipe diameter of 1000mm, the flow velocity v under the rated flow rate can be calculated as v = 5.3m / s. At a certain moment, the acquired density ρ = 1.4g / cm 3The total pipeline resistance h = 68m was calculated using the mud pipeline resistance formula (the Hassen-Williams formula or Darcy-Weisbach formula applicable to dredging projects, combined with parameters such as pipeline material and roughness). Since 68m > 65m (P = 65m), Mode 2 determines that there is a risk of pipe blockage.

[0058] (III) Execution Control:

[0059] When either Mode 1 or Mode 2 determines there is a risk of pipe blockage, the control module immediately sends a command to the power regulation module to increase the mud pump power. For example, when Mode 1 determines there is a risk of pipe blockage, the mud pump power increases from the current 10,000 kW to 12,000 kW; when Mode 2 determines there is a risk of pipe blockage, the mud pump power is further adjusted to 13,000 kW to increase the mud conveying pressure and reduce the risk of pipe blockage.

[0060] III. Density Dynamic Correction Process:

[0061] After the mud pump starts, no density dynamic correction data is collected for the first 30 minutes. After 30 minutes, data is collected every 30 minutes. Assume that during the mud pump's operation, the cumulative flow length reaches the set threshold of 15000m. At this point, if the collected density ρ = 0.9 g / cm³... 3 <ρ1(1.0g / cm 3 ) or ρ = 2.1 g / cm 3 >ρ2(2.0g / cm 3 Then, the constant A is adjusted according to the relationship between density and viscosity. For example, when the density ρ = 0.9 g / cm³ 3 <1.0g / cm 3 At that time, by consulting the table of the relationship between the density and viscosity of this type of mud obtained by the laboratory, it was found that the current viscosity was 15% lower than the standard value. Based on the degree of deviation, the constant A was adjusted from the original 0.85 to 0.78 to achieve dynamic correction of density and ensure the accuracy of pipe blockage risk assessment.

[0062] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring and controlling the power of a suction dredge pump during long distance complex slurry transport, characterized in that, The method comprises the following steps: (1) Parameter monitoring: a mud density meter, a pressure transmitter, and an electromagnetic flowmeter or an acoustic flowmeter are installed at the outlet of the mud pump pipeline to collect mud density ρ, pump pressure P, and flow rate v in real time; the mud density meter is used to measure the density change of the mud; the pressure transmitter is used to acquire pump pressure data in real time; and the electromagnetic flowmeter or the acoustic flowmeter is used to accurately monitor the flow information of the mud; (2) Blockage risk judgment and power adjustment: the judgment is performed in any of the following modes: Mode one: based on the density ρ and flow velocity v collected in real time, the flow length L1=v×t is calculated combined with the collection time interval t, and the pipeline loss h of L1 length is obtained; if the condition is met, it is determined that there is no risk of pipe blockage; if the condition is met, it is determined that there is a risk of pipe blockage; Mode two: based on the density ρ and the flow rate v under the rated flow, the total resistance h of the mud pipeline is calculated through a mud pipeline resistance formula; if h < P, it is determined that there is no blockage risk; if h > P, it is determined that there is a blockage risk; (3) Execution control: when it is determined that there is a blockage risk in any mode, the power of the mud pump is immediately increased. (4) Density dynamic correction: collect data every 30 minutes since the mud pump starts; when the cumulative flow length ∑L1 = L, if then adjust the constant A according to the relationship between density and viscosity.

2. The method according to claim 1, wherein the method is characterized by: In mode one of step (2), the mud pump power is increased while the mud flow is simultaneously controlled to be not lower than the flow corresponding to the real-time collected flow rate v.

3. The method according to claim 1, wherein the method is characterized by: In mode two of step (2), the mud pump power is increased while the mud flow is ensured to reach the rated flow.

4. The mud pump power monitoring and control method for long-distance complex mud delivery of the cutter suction dredger according to claim 1, characterized in that: In the density dynamic correction of step (4), the cumulative flow length ΣL1 satisfies: where L 1i = v i x t.

5. The method of claim 1, wherein the method further comprises: determining a distance between the suction dredger and the discharge site; and determining a distance between the suction dredger and the suction dredger's discharge site; and determining a distance between the suction dredger and the suction dredger's discharge site. The mud density meter is used to monitor the density change of the mud in real time, and the accuracy error is ≤±0.5%.

6. The method for monitoring and controlling the power of the suction dredger's pumps during long distance complex slurry transportation according to claim 1, characterized in that: The sampling frequency of the pressure transmitter is ≥10 Hz, and the pump pressure fluctuation is monitored in real time.

7. The method for monitoring and controlling the power of the mud pump during long-distance complex mud transportation by a dredging vessel according to claim 1, characterized in that: The flow monitoring error of the electromagnetic flowmeter or the acoustic flowmeter is ≤±1.5%.

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