A method for calculating carbon emissions of trailing suction hopper dredgers

Abstract

The present invention discloses a method for calculating carbon emissions of a trailing suction hopper dredger, including: Step S1, calculating the shaft power of the mud pump; Step S2, calculating the shaft power of the high-pressure water jet pump; Step S3, calculating the main propulsion power of the trailing suction hopper dredger; Step S4, calculating the resistance power of the dredging head; Step S5, according to the power calculation results of Steps S1-S4, forming a total ship power calculation model, inputting construction status, process parameters, construction section, and construction time, calculating the instantaneous total power of the ship, and then calculating carbon emissions; Step S6, integrating the calculation model to calculate the carbon emissions during the construction period; Step S7, measuring the construction periods of different construction sections of the waterway; Step S8, according to the measured construction periods of different construction sections, arranging different ships for construction in different construction sections, and calculating the total comprehensive carbon emissions of the fleet in different construction sections. The present invention greatly improves the dredging efficiency, reduces energy consumption, and reduces carbon emissions.

Description

Technical Field

[0001] The present invention relates to a method for calculating carbon emissions of a trailing suction hopper dredger. Background Art

[0002] According to the 2021 Global Carbon Dioxide Emissions Statistical Report of the International Energy Agency (IEA), the global CO2 emissions related to energy reached 3.63 billion tons, hitting a record high. According to statistics, the top five carbon-emitting industries in China are power and heat, manufacturing and construction, industry, transportation, and agriculture. In recent years, significant achievements have been made in carbon accounting and emission reduction measures for high-carbon-emitting industries in China.

[0003] There have been many studies on regional carbon emissions at scales such as global, national, provincial, main functional areas, counties and cities, and grids. Most of them start from a single perspective such as land use, industry, and energy. Research on carbon emission space, such as issues like carbon emission differences between cities, carbon budgets, and carbon spillover, mostly focuses on a relatively large research scope, lacking comprehensive accounting of carbon emissions within small-scale estuary regions and research on their spatial differentiation. Currently, there are only a few cases for reference regarding relevant research on carbon emissions in the Yangtze Estuary at home and abroad. Therefore, the accounting and spatial distribution research on carbon emissions in the Yangtze Estuary dredging industry are very insufficient.

[0004] As the main ship in the dredging construction industry, the trailing suction hopper dredger has technical characteristics such as self-loading, self-navigation, self-unloading, flexibility, strong resistance to wind and waves, and the ability to discharge dredged spoil to the landfill area. Therefore, it is widely used in engineering fields such as port channel excavation and maintenance. The traditional construction process of the trailing suction hopper dredger for "digging, transporting, and dumping" is relatively mature. Facing complex construction conditions, a huge construction machinery operation system, and a large number of dynamic construction parameters, optimizing the selection of appropriate construction processes according to different engineering characteristics can not only greatly improve the dredging efficiency but also reduce energy consumption and carbon emissions.

[0005] Therefore, a method for calculating carbon emissions of a trailing suction hopper dredger is provided. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for calculating carbon emissions of a trailing suction hopper dredger to overcome the existing defects, which can greatly improve the dredging efficiency, reduce energy consumption, and reduce carbon emissions.

[0007] The technical solution to achieve the above purpose is as follows:

[0008] A method for calculating carbon emissions of a trailing suction hopper dredger includes:

[0009] Step S1, calculating the shaft power of the mud pump;

[0010] Step S2, calculating the shaft power of the high-pressure flush water pump;

[0011] Step S3, calculate the main propulsion power of the trailing suction hopper dredger;

[0012] Step S4, calculate the drag power of the drag head;

[0013] Step S5, according to the power calculation results of the above steps S1 - S4, form a total ship power calculation model, input the construction status, process parameters, construction section, and construction time, calculate the instantaneous total power of the ship, and then calculate the carbon emissions;

[0014] Step S6, integrate the calculation model to calculate the carbon emissions during the construction period;

[0015] Step S7, measure the construction period of different construction sections of the waterway;

[0016] Step S8, according to the measured construction periods of different construction sections, arrange different ships for construction in different construction sections, and calculate the total comprehensive carbon emissions of the fleet in different construction sections.

[0017] Preferably, in the above step S1, the calculation process of the mud pump shaft power is as follows:

[0018] Calculate the mud pump shaft power according to the calculated effective power of the mud pump and the actual pump efficiency. The calculation formula is as follows:

[0019] ;

[0020] In the formula, P 有效 is the effective power of the mud pump, H is the head of the mud pump, Q1 is the displacement of the mud pump, ρ is the density of the slurry, and g is the acceleration due to gravity;

[0021] Among them,

[0022] ;

[0023] In the formula, V is the flow velocity, and r is the radius of the discharge pipe of the mud pump;

[0024] ;

[0025] In the formula, V2 is the discharge port flow velocity, V1 is the suction port flow velocity, P2 is the discharge port pressure, P1 is the suction pressure, and h is the vertical height distance between the discharge port pressure gauge and the center of the mud pump suction port;

[0026] The mud pump head includes four parts: one is the velocity head, the second is the pressure head, the third is the elevation head, and the fourth is the frictional resistance loss and elbow resistance loss. Among them,

[0027] ;

[0028] Wherein, K1 and K2 are resistance coefficients, L is the straight pipe length of the mud pipe, D is the inner diameter of the straight pipe of the mud pipe, and g is the acceleration of gravity;

[0029] According to the flow rate-efficiency curve fitting formula, the actual pump efficiency is empirically selected as 0.8 of the theoretical pump efficiency, that is:

[0030] ;

[0031] Wherein, η 实际 is the actual pump efficiency of the mud pump, η 理论 is the theoretical pump efficiency of the mud pump, which is obtained through the flow rate-efficiency curve fitting formula in the clear water test, and the flow velocity is the direct acquisition reading of the ship flowmeter.

[0032] Preferably, in the step S2, the calculation process of the shaft power of the high-pressure flush water pump is as follows:

[0033] Statistically analyze the rotation speed, pressure, and power of the high-pressure water pump, draw the characteristic curves of the high-pressure water pump at different rotation speeds, and the characteristic curves include the flow velocity-rotation speed-head curve, the flow velocity-rotation speed-power curve, and the flow velocity-rotation speed-efficiency curve, and fit to obtain the formula;

[0034] Determine the flow rate according to the flow velocity of the high-pressure water pump, that is:

[0035] ;

[0036] Wherein, V G is the flow velocity of the high-pressure water pump, S G is the discharge pipe diameter area of the high-pressure water pump, r G is the discharge pipe radius of the high-pressure water pump, R G is the discharge pipe diameter of the high-pressure water pump;

[0037] According to the flow velocity and combined with the flow velocity-rotation speed-head curve, obtain:

[0038] ;

[0039] Determine the pump efficiency discount ratio F according to the actual pressure and the theoretical pressure;

[0040] ;

[0041] According to the calculated theoretical pressure at different rotation speeds, take the ratio with the actual pressure to obtain the pump efficiency discount ratio F at different rotation speeds, and average to obtain the pump efficiency discount ratio, that is:

[0042] ;

[0043] Wherein, F a is the pump efficiency discount ratio of the a-th group of rotation speeds, and a is the number of rotation speed groups;

[0044] Determine the pipeline characteristics based on the flow rate and actual pressure, i.e.:

[0045] The total resistance of the pipeline system consists of the following two parts:

[0046] ;

[0047] Among them, H G静 is the static head of the elevation difference between the inlet and outlet of the pipeline, and the loss head H G损失 includes the frictional loss along the way and the local resistance loss, and is proportional to the square of the flow rate Q2, i.e.:

[0048] ;

[0049] In the formula, k is the pipeline characteristic coefficient;

[0050] Furthermore, establish the pipeline characteristic equation. Assume that H G静 = h, the energy difference generated by the fluid in the pipeline system due to the vertical height difference between the inlet and outlet, i.e.:

[0051] ;

[0052] The actual operating point of the pump satisfies:

[0053] ;

[0054] Subtract the static head h from each group of H 泵i to obtain the corrected head:

[0055] ;

[0056] Fit and calculate the pipeline characteristic coefficient k. Use the least squares method to fit the data and obtain the pipeline characteristic coefficient k:

[0057] ;

[0058] In the formula, Q 2i is the flow rate at different rotational speeds of the high-pressure water pump, and H 泵i is the head at different rotational speeds of the high-pressure water pump;

[0059] Calculate the corresponding flow rate according to different pressures and pipeline characteristics, determine the theoretical efficiency by looking up the table according to the corresponding flow velocity, determine the actual pump efficiency according to the theoretical efficiency and the pump efficiency discount ratio, determine the effective power according to the pressure and flow rate, and determine the actual shaft power according to the effective power and the actual pump efficiency, i.e.:

[0060] ;

[0061] That is:

[0062] ;

[0063] In the formula, P G实功 is the actual power of the high-pressure water pump, η G实际 is the actual pump efficiency of the high-pressure water pump, η G理论 is the theoretical pump efficiency of the high-pressure water pump.

[0064] Preferably, in the step S3, the calculation process of the main propulsion power of the trailing suction hopper dredger is as follows:

[0065] According to the principles of physics, in ship propulsion, the propulsion power is used to overcome the resistance of the ship to make the ship move forward. When the ship is sailing at a constant speed, the propulsion force is equal to the resistance of the ship, that is:

[0066] ;

[0067] That is:

[0068] ;

[0069] In the formula, P C is the main propulsion power of the trailing suction hopper dredger, R is the resistance of the trailing suction hopper dredger, V C is the speed of the trailing suction hopper dredger, R f is the frictional resistance, R w is the wave-making resistance, R s is the form resistance;

[0070] Among them,

[0071] The frictional resistance R f is proportional to That is:

[0072] ;

[0073] To simplify the calculation, a frictional resistance coefficient i is set, which is related to the hull roughness, wetted surface area and Reynolds number. , and the empirical value of the frictional resistance coefficient i for the trailing suction hopper dredger is 0.35 - 0.50;

[0074] For low-speed ships, the proportion of the wave-making resistance R w in the total resistance is relatively small. For high-speed ships, the wave-making resistance R w becomes the main resistance component. When the ship speed exceeds the critical value, the wave-making resistance increases sharply, and its growth rate is much faster than the frictional resistance, and is proportional to the square or higher power of the ship speed, that is:

[0075] ;

[0076] In the formula, n ≥ 2, and n takes 3;

[0077] To simplify the calculation, a wave-making resistance coefficient j is set such that , and the empirical value of the wave-making resistance coefficient j for a trailing suction hopper dredger is 0.03 - 0.06;

[0078] The ITTC empirical formula is used to calculate the form resistance R s , that is:

[0079] ;

[0080] The Holtrop formula is used to calculate the wetted surface area S of the hull C :

[0081] ;

[0082] In the formula, ρ1 is the density of water, S C is the wetted surface area of the hull, C DS is the form resistance coefficient, B is the beam of the ship, T is the draft, C B is the block coefficient of the ship, and L1 is the length of the ship;

[0083] The calculation formula for the block coefficient of the ship is as follows:

[0084] ;

[0085] In the formula, is the displacement volume, and Δ is the full load displacement;

[0086] Furthermore, it is obtained that:

[0087] ;

[0088] In the formula, i is the frictional resistance coefficient, and j is the wave-making resistance coefficient;

[0089] Finally, it is obtained that:

[0090] .

[0091] Preferably, in the step S4, the calculation process of the drag power of the drag head is as follows:

[0092] Obtain the main engine power, auxiliary generator power, and corresponding construction parameters of the ship in different sections and at different times;

[0093] According to the main engine and auxiliary engine powers, deduct the calculated values of the mud pump, high-pressure flushing, and propulsion power, obtain the power corresponding to the drag head and drag arm resistances, and establish a relationship with the dredging speed, that is:

[0094] ;

[0095] Calculate to obtain P 耙阻功, corresponding to the dredging speed V C , plot a curve and establish P 耙阻功 The fitting relationship with the ship speed:

[0096] ;

[0097] In the formula, P 主瞬 is the instantaneous total power of the ship, P 辅发 is the auxiliary engine power, η is the efficiency of the trailing suction dredger, P 辅助 is the power of the ship's auxiliary equipment, and a, b, and c are all fitting parameters of P 耙阻功 and the ship speed.

[0098] Preferably, in the step S5, the construction state, process parameters, construction section, and construction time are input into the calculation model to calculate the instantaneous total power of the ship, and then the carbon emissions are calculated, that is:

[0099] The instantaneous total power of the ship P 主瞬 :

[0100] ;

[0101] Each ship refers to the fuel consumption at 50%, 75%, 80%, and 100% loads in the main engine bench test. When the instantaneous total power falls within a certain range of the main engine power, the instantaneous fuel consumption rate of this range is adopted. The instantaneous emission time is t, then:

[0102] ;

[0103] In the formula, M1 is the fuel consumption, and F is the fuel consumption rate;

[0104] Calculate the instantaneous carbon emissions according to the carbon dioxide emission coefficient table CFj:

[0105] Fuel mode:

[0106] ;

[0107] Gas mode:

[0108] ;

[0109] That is:

[0110] ;

[0111] In the formula, M1 is the total instantaneous fuel consumption, M2 is the total instantaneous gas consumption, M3 is the total instantaneous ignition oil fuel consumption, L is the LNG consumption in the gas mode, the LNG calorific value is 49539 kJ / kg, and D1 is the ignition oil consumption rate in the gas mode, taking the average value of 11.4 kg / h;

[0112] In actual operation, introduce the incomplete combustion error coefficient to correct the emission calculation k 燃烧 , that is:

[0113] ;

[0114] If the main engine power is below 50% of the rated power and in the low-load combustion stage, the combustion efficiency η 燃烧 further decreases, and k 燃烧 needs to be corrected:

[0115] ;

[0116] In the formula, α is the operating condition coefficient, taking 0.3 - 0.5, and η 设计 is the combustion efficiency under the design condition.

[0117] Preferably, in the step S6, by integrating the instantaneous carbon emissions during the construction period, the total carbon emissions of the construction period are obtained, that is, a construction vessel includes dredging q 1. Heavy-load navigation q 2. Mud dumping q 3. Light-load navigation to the dredging area q 4 four sub-units, count the earthwork volume of each single-vessel construction unit within a month, and obtain the average earthwork volume of the single-vessel construction unit m 土 , and then according to the earthwork volume of a single construction section M 土 , the total number of vessel units A , M 土 can be determined by geological exploration, engineering design documents or on-site measurement. The calculation formula of the vessel unit A is as follows:

[0118] ;

[0119] Calculate the carbon emissions of a single construction section C 燃油单 or C 燃油单 , and the calculation formula is as follows:

[0120] Fuel mode:

[0121] ;

[0122] In the formula, C 燃油 is the carbon emissions per vessel in the fuel mode;

[0123] Take

[0124] ;

[0125] Substitute , and calculate the carbon emissions of the ship per day in a single construction section in fuel mode;

[0126] Gas mode:

[0127] ;

[0128] In the formula, C 燃气 is the carbon emissions per voyage in gas mode;

[0129] Substitute

[0130] ;

[0131] Substitute into , and calculate the carbon emissions of the ship per day in a single construction section in gas mode.

[0132] Preferably, in step S7, according to historical data, measure the earthwork volume of each construction section of the Yangtze Estuary waterway, count the operation time and earthwork volume of each voyage of different ships in a single construction section, and according to the average number of construction ships S per day 平均 and the average earthwork volume per voyage m 土 , convert it to 26 days according to the effective working days per month, and calculate the monthly earthwork volume of different ships in a certain construction section M 月 : [[ID=4�]]

[0133] ;

[0134] According to the total monthly construction earthwork volume of different ships invested in this section and the measured earthwork volume of the section, calculate the construction period T z :

[0135] .

[0136] Preferably, in step S8, calculate the carbon emissions per day per voyage of a single ship according to historical data C 燃油 or C 燃气 , and then according to the number of construction ships A per day in the construction section, the daily carbon emissions of a single ship in this section can be calculated C 燃气单 or C 燃气单 , finally, according to the construction period T z , calculate the total carbon emissions of each ship or .

[0137] The beneficial effects of the present invention are as follows: the present invention obtains the mud pump shaft power by calculation, thereby providing key parameter support for ship operation; and provides a method for analyzing the resistance of the ship and more accurately calculating the propulsion power. By accurately estimating the shape resistance, the influence of various resistance factors on the ship when traveling in the water can be better understood. At the same time, the use of empirical formulas to calculate the wet surface area and the displacement volume is helpful to quickly estimate the relevant parameters of the ship in practical applications, and provide an important reference basis for ship design and operation; the construction period of different construction sections of the waterway is calculated by using empirical formulas, simulation calculations or actual measurements. By calculating the carbon emissions of different sections and different ship types, a basis for energy conservation and emission reduction is provided, and a reference for the design and operation of the ship is also provided; through the method of the present invention, the operation sequence of the ship can be reasonably arranged, the waiting time and empty mileage of the ship can be reduced, the construction efficiency can be improved, and energy consumption and carbon emissions can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0138] Figure 1 This is a flow chart of a method for calculating carbon emissions from a trailing suction hopper dredger according to the present invention;

[0139] Figure 2 This is the water cleaning efficiency curve of the new Haihu No. 4 mud pump in the embodiment of the present invention;

[0140] Figure 3 2. The flow rate-water cleaning efficiency curve of the new manatee mud pump in the embodiment of the present invention;

[0141] Figure 4 : This is the flow rate-clean water efficiency curve of the new Haihu mud pump in the embodiment of the present invention;

[0142] Figure 5 This is the flow rate-efficiency curve of the clean water test of the Haihu No. 8 mud pump in the embodiment of the present invention;

[0143] Figure 6 : This is the flow rate-lift curve of the Haihu No. 8 high-pressure water pump in the embodiment of the present invention;

[0144] Figure 7 : This is the flow rate-power curve of the Haihu No. 8 high-pressure water pump in the embodiment of the present invention;

[0145] Figure 8 2. Flow rate-efficiency curve of Haihu No. 8 high-pressure water pump in the embodiment of the present invention;

[0146] Figure 9 This is the ground speed-drag head resistance power curve of the new Sea Tiger 4 D3.0 section in the embodiment of the present invention;

[0147] Figure 10It is the ground speed - draghead resistance power curve of the D3.1 section of Xin Hai Hu 4 in the embodiment of the present invention;

[0148] Figure 11 It is the ground speed - draghead resistance power curve of the D3.2 section of Xin Hai Hu 4 in the embodiment of the present invention;

[0149] Figure 12 It is the ground speed - draghead resistance power curve of the D3.3 section of Xin Hai Hu 4 in the embodiment of the present invention;

[0150] Figure 13 It is the ground speed - draghead resistance power curve of the D3.4 section of Xin Hai Hu 4 in the embodiment of the present invention;

[0151] Figure 14 It is the ground speed - draghead resistance power curve of the extended section of Xin Hai Hu 4 in the embodiment of the present invention;

[0152] Figure 15 It is the schematic diagram of soil classification and correction coefficient values in the embodiment of the present invention. Detailed implementation manners

[0153] Next, the technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0154] Next, the present invention will be further described in conjunction with the accompanying drawings.

[0155] As Figure 1 shown, a method for calculating the carbon emissions of a trailing suction hopper dredger includes:

[0156] Step S1, calculating the shaft power of the mud pump.

[0157] In the embodiment, the calculation process of the shaft power of the mud pump is as follows:

[0158] According to the calculated effective power of the mud pump and the actual pump efficiency, calculate the shaft power of the mud pump, and its calculation formula is as follows:

[0159] ;

[0160] In the formula, P 有效is the effective power of the mud pump, H is the head of the mud pump, Q1 is the displacement of the mud pump, ρ is the density of the slurry, and g is the acceleration due to gravity;

[0161] Among them,

[0162] ;

[0163] In the formula, V is the flow velocity and r is the radius of the discharge pipe of the mud pump;

[0164] ;

[0165] In the formula, V2 is the discharge port flow velocity, V1 is the suction port flow velocity, P2 is the discharge port pressure, P1 is the suction pressure, and h is the vertical height distance between the discharge port pressure gauge and the center of the mud pump suction port;

[0166] The head of the mud pump consists of four parts. One is the velocity head, the second is the pressure head, the third is the elevation head, and the fourth is the frictional resistance loss and elbow resistance loss. Among them,

[0167] ;

[0168] In the formula, K1 and K2 are resistance coefficients, which can be queried in the "Code for Design of Dredging and Hydraulic Filling Engineering (JTS 181-5-2012)". L is the straight pipe length of the mud pipe, D is the inner diameter of the straight mud pipe, and g is the acceleration due to gravity;

[0169] According to the flow rate - efficiency curve fitting formula, the actual pump efficiency is empirically selected as 0.8 of the theoretical pump efficiency, that is:

[0170] ;

[0171] In the formula, η 实际 is the actual pump efficiency of the mud pump, η 理论 is the theoretical pump efficiency of the mud pump, which is obtained through the flow rate - efficiency curve fitting formula in the clear water test, and the flow velocity is the direct acquisition reading of the ship flowmeter.

[0172] The above formulas incorporate multiple parameters and accurately calculate the shaft power of the mud pump. Among them, the calculation of the mud pump head takes into account multiple factors such as the velocity head, pressure head, elevation head, and frictional resistance loss and elbow resistance loss, making the calculation results more accurately reflect the actual situation. By dividing the effective power of the mud pump by the actual pump efficiency, the shaft power of the mud pump is obtained, providing key parameter support for ship operation.

[0173] Taking Haihu No. 4 as an example:

[0174] Such as Figure 2 shown, in the construction report of Haihu No. 4, by screening out the slurry concentration greater than 1.1 t / m³, the following dredging parameters (average values) are obtained

[0175] The mud density ρ is 1.24 t / m³, the flow velocity is 7.79 m / s, the inlet pressure P1 is -0.37 bar, the discharge pressure P2 is 0.65 bar, and the diameter D of the discharge pipe of the mud pump is DN900 mm;

[0176] Position head: The vertical height distance between the pressure gauge at the discharge port and the center of the suction port of the mud pump. For Haihu No. 4, it is approximately 8 m.

[0177] ;

[0178] Taking Xin Hainiu or Xin Haihu as an example:

[0179] Such as Figure 3 shown, Xin Hainiu η 理论 is obtained through the flow velocity - efficiency fitting formula in the clear water test, and the flow velocity is read by the flow meter:

[0180] ;

[0181] Such as Figure 4 shown, Xin Haihu η 理论 is obtained through the flow velocity - efficiency fitting formula in the clear water test, and the flow velocity is read by the flow meter:

[0182] ;

[0183] The calculation of the shaft power of Xin Hainiu and Xin Haihu is the same as the calculation steps of Haihu No. 4.

[0184] Taking Haihu No. 8 / 9 as an example:

[0185] Such as Figure 5 shown, according to the fine - particle loading model (mixed model), in accordance with the sediment particle size and particle size percentage distribution in the Yangtze Estuary area, combined with the clear water efficiency and shaft power of the mud pump, the optimal loading flow rate of the double - pump is calculated to be 21000 m³ / h, the average flow velocity of the single - pump is 4.58 m / s. According to the proportional relationship between the mud pump flow rate and the rotational speed Q1 / Q2 = n1 / n2, the rotational speed at this time is 160 rpm, and it is obtained through the flow velocity - efficiency fitting formula in the clear water test:

[0186] ;

[0187] According to the formula:

[0188] ;

[0189] Perform the calculation of the shaft power of the mud pump.

[0190] Step S2, calculate the shaft power of the high - pressure flushing water pump.

[0191] In the embodiment, the calculation process of the shaft power of the high-pressure flush water pump is as follows:

[0192] Statistically analyze the rotational speed, pressure, and power of the high-pressure water pump, and plot the characteristic curves of the high-pressure water pump at different rotational speeds. The characteristic curves include flow velocity - rotational speed - head curves, flow velocity - rotational speed - power curves, and flow velocity - rotational speed - efficiency curves, and fit to obtain formulas;

[0193] According to the data of the clear water test of the high-pressure flush water pump of Haihu No. 8, combine with the specific speed method, and plot the characteristic curves at different rotational speeds, as shown in Table 1:

[0194] Table 1

[0195]

[0196] Determine the flow rate according to the flow velocity of the high-pressure water pump, that is:

[0197] ;

[0198] In the formula, V G is the flow velocity of the high-pressure water pump, S G is the area of the discharge pipe diameter of the high-pressure water pump, r G is the radius of the discharge pipe of the high-pressure water pump, R G is the diameter of the discharge pipe of the high-pressure water pump;

[0199] According to the flow velocity and the flow velocity - rotational speed - head curve, obtain:

[0200] ;

[0201] Determine the pump efficiency discount ratio F according to the actual pressure and the theoretical pressure;

[0202] ;

[0203] Calculate the theoretical pressure at different rotational speeds, take the ratio with the actual pressure, obtain the pump efficiency discount ratio F at different rotational speeds, and average to obtain the pump efficiency discount ratio, that is:

[0204] ;

[0205] In the formula, F a is the pump efficiency discount ratio of the a-th group of rotational speeds, and a is the number of rotational speed groups;

[0206] The total resistance of the pipeline system consists of the following two parts:

[0207] ;

[0208] Among them, H G静 is the static head of the elevation difference between the inlet and outlet of the pipeline, and the loss head H G损失It includes the frictional loss along the pipeline and the local resistance loss, which is proportional to the square of the flow rate Q2, i.e.:

[0209] ;

[0210] In the formula, k is the pipeline characteristic coefficient, comprehensively reflecting the geometric parameters of the pipeline (length, diameter, roughness) and the local resistance (valves, elbows, etc.);

[0211] Furthermore, a pipeline characteristic equation is established. Assuming H G静 = h, the energy difference generated by the fluid in the pipeline system due to the vertical height difference between the inlet and outlet is ignored, i.e.:

[0212] ;

[0213] The actual operating point of the pump satisfies:

[0214] ;

[0215] Subtracting the static head h from each group of H 泵i gives the corrected head:

[0216] ;

[0217] The pipeline characteristic coefficient k is fitted and calculated. The data is fitted using the least squares method to obtain the pipeline characteristic coefficient k:

[0218] ;

[0219] In the formula, Q 2i is the flow rate of the high-pressure water pump at different rotational speeds, and H 泵i is the head of the high-pressure water pump at different rotational speeds;

[0220] According to different pressures and pipeline characteristics, the corresponding flow rates are calculated. The theoretical efficiency is determined by looking up the table based on the corresponding flow velocities. The actual pump efficiency is determined based on the theoretical efficiency and the pump efficiency discount ratio. The effective power is determined based on the pressure and flow rate. The actual shaft power is determined based on the effective power and the actual pump efficiency, i.e.:

[0221] ;

[0222] That is:

[0223] ;

[0224] In the formula, P G实功 is the actual power of the high-pressure water pump, η G实际 is the actual pump efficiency of the high-pressure water pump, and η G理论 is the theoretical pump efficiency of the high-pressure water pump.

[0225] Taking Xin Hai Hu 8 as an example:

[0226] 1) Statistically analyze the rotational speed, pressure, and power of the high-pressure water pump of Xinhaihu 8, as shown in Table 2.

[0227] Table 2

[0228]

[0229] 2) Based on the data from the clean water test of the high-pressure water pump of Haihu 8 and combined with the speed ratio method, plot the characteristic curves at different rotational speeds: flow velocity - head curve, flow velocity - power curve, flow velocity - efficiency curve, as Figures 6 - 8 shown.

[0230] 3) Determine the flow rate based on the power and rotational speed of the high-pressure water pump;

[0231] 4) Determine the theoretical pressure based on the flow rate and rotational speed;

[0232] 5) Determine the pump efficiency discount ratio (average value of multiple groups of data) based on the actual pressure and theoretical pressure;

[0233] 6) Determine the pipeline characteristics based on the flow rate and actual pressure;

[0234] 7) Calculate the corresponding flow rate according to different pressures and pipeline characteristics, determine the theoretical efficiency by looking up the table based on the corresponding flow velocity, determine the actual pump efficiency based on the theoretical efficiency and the pump efficiency discount ratio, determine the effective power based on the pressure and flow rate, and determine the actual shaft power based on the effective power and the actual pump efficiency;

[0235] That is

[0236] Based on the pipeline characteristic curve coefficient obtained in step 6 and knowing the discharge pressure, ,

[0237] , obtain the system head H G , according to , obtain the flow rate corresponding to the discharge pressure;

[0238] Determine the theoretical efficiency according to the corresponding flow rate table and the fitting formula in the flow rate - efficiency curve.

[0239] Based on the theoretical efficiency and the pump discount ratio K, take the average to obtain the pump efficiency discount ratio and determine the actual pump efficiency:

[0240] ;

[0241] Determine the effective power based on the pressure and flow rate:

[0242] ;

[0243] Determine the actual shaft power based on the effective power and the actual pump efficiency:

[0244] 。

[0245] Step S3, calculate the main propulsion power of the trailing suction hopper dredger.

[0246] In the embodiment, the calculation process of the main propulsion power of the trailing suction hopper dredger is as follows:

[0247] According to the principle of physics, in ship propulsion, the propulsion power is used to overcome the resistance suffered by the ship to make the ship move forward. When the ship is sailing at a constant speed, the propulsive force is equal to the resistance suffered by the ship, that is:

[0248] ;

[0249] That is:

[0250] ;

[0251] In the formula, P C is the main propulsion power of the trailing suction hopper dredger, R is the resistance suffered by the trailing suction hopper dredger, V C is the speed of the trailing suction hopper dredger, R f is the frictional resistance, R w is the wave-making resistance, R s is the form resistance;

[0252] Among them,

[0253] The frictional resistance R f is the tangential force generated on the hull surface due to the viscosity of water. It is related to factors such as the wetted surface area of the hull, the kinematic viscosity coefficient of water, the ship speed, and the surface roughness of the hull. The frictional resistance R f is proportional to That is:

[0254] ;

[0255] To simplify the calculation, a frictional resistance coefficient i is set, which is related to the hull roughness, wetted surface area, and Reynolds number. , and the empirical value of the frictional resistance coefficient i for the trailing suction hopper dredger is 0.35 - 0.50;

[0256] The wave-making resistance R w is the resistance corresponding to the energy consumed by the waves generated when the ship is sailing. Its relationship with the ship speed is relatively complex and is usually related to the square, cube, or even higher powers of the ship speed. For low-speed ships, the proportion of the wave-making resistance R w in the total resistance is relatively small. For high-speed ships, the wave-making resistance R wBecomes the main resistance component. When the ship speed exceeds the critical value, the wave-making resistance increases sharply, and its growth rate is much faster than that of the frictional resistance, being proportional to the square or higher power of the ship speed, i.e.:

[0257] ;

[0258] In the formula, n≥2, and n takes 3;

[0259] To simplify the calculation, a wave-making resistance coefficient j is set such that , and the empirical value of the wave-making resistance coefficient j for a trailing suction hopper dredger is 0.03 - 0.06;

[0260] Form drag R s Is mainly the resistance generated due to the separation of the water flow at the stern of the ship to form vortices. It is also related to the ship speed and is greatly affected by the hull shape;

[0261] Form drag R s Generally increases with the increase of the ship speed. Although the proportion it accounts for in the total resistance is usually less than that of the frictional resistance R f and the wave-making resistance R w , it may also have a significant impact on the resistance characteristics of the ship in some special cases (such as unreasonable hull shape design).

[0262] Form drag R s The magnitude depends on the rationality of the hull shape; by optimizing the hull design and reducing the separation of the water flow at the stern and the formation of vortices, the form drag R s can be reduced; during the ship design process, the impact of form drag needs to be fully considered, and advanced design concepts and technologies should be adopted to improve the performance and efficiency of the ship;

[0263] Based on the tide level, tidal current velocity data, and propulsion power table, establish the dredging and navigation propulsion power of the trailing suction hopper dredger in different sections and at different times of the deep water channel;

[0264] When establishing the dredging and navigation propulsion power of the trailing suction hopper dredger in different sections and at different times of the deep water channel, the changes in the tide level and tidal current velocity data need to be fully considered; the height of the tide level will affect the draft and buoyancy of the ship, thus affecting the demand for propulsion power. The magnitude and direction of the tidal current velocity will also have an impact on the navigation of the ship, increasing or decreasing the consumption of propulsion power;

[0265] First, based on the obtained tide level and tidal current velocity data, analyze the water flow conditions in different sections and at different times. Combining with the data in the propulsion power table, the propulsion power requirements of the trailing suction hopper dredger under specific conditions can be preliminarily determined. Then, consider the impact of the dredging operation on the propulsion power; during the dredging process, the ship needs to overcome the resistance of the soil and its own weight, which will increase the consumption of propulsion power; by analyzing the characteristics and requirements of the dredging operation, the propulsion power can be further adjusted and optimized;

[0266] In addition, other factors affecting the propulsion power can also be considered, such as wind direction, sea waves, etc. Although these factors are relatively small, they may also have a certain impact on the ship's propulsion power in some cases. By comprehensively considering various factors, a more accurate and practical propulsion power model for the trailing suction hopper dredger's dredging and navigation can be established, providing strong support for ship operation and management;

[0267] In actual calculations, some empirical formulas are often used to estimate the form resistance R s , that is, the ITTC empirical formula is used to calculate the form resistance R s , that is:

[0268] ;

[0269] The Holtrop formula is used to calculate the wetted surface area S of the hull C :

[0270] ;

[0271] In the formula, ρ1 is the density of water, S C is the wetted surface area of the hull, C DS is the form resistance coefficient, B is the beam of the ship, T is the draft, C B is the block coefficient of the ship, and L1 is the length of the ship;

[0272] The calculation formula for the block coefficient of the ship is as follows:

[0273] ;

[0274] In the formula, is the displacement volume, and Δ is the full load displacement;

[0275] Furthermore, we get:

[0276] ;

[0277] In the formula, i is the friction resistance coefficient and j is the wave-making resistance coefficient; according to the current draft T of the ship and the speed V relative to the water CWhen calculating the propulsion power, the friction resistance coefficient i and the wave-making resistance coefficient j will change, based on a clean hull (roughness ks≈150 μm) and the standard wetted surface area. For a trailing suction hopper dredger, due to fouled bottom and sediment attachment, the roughness may reach ks≥300 μm, and the friction resistance coefficient needs to be increased, i = 0.35 - 0.50; since the economic speed of a trailing suction hopper dredger is low, the full-load design speed is 12 - 14 kn, and the dredging speed is at a low Froude number Fr (Fr < 0.15), the proportion of wave-making resistance decreases, and the form resistance is dominant, so the wave-making resistance coefficient needs to be decreased, j = 0.03 - 0.06;

[0278] Finally, we get:

[0279] 。

[0280] The parameters of each ship are shown in Table 3:

[0281] Table 3

[0282]

[0283] When establishing the excavation and navigation propulsion power of a trailing suction hopper dredger in different sections and at different times of a deep-water channel, it is necessary to fully consider the changes in tide level and tidal current velocity data. The height of the tide level will affect the draft and buoyancy of the ship, thus affecting the demand for propulsion power. The magnitude and direction of the tidal current velocity will also have an impact on the navigation of the ship, increasing or decreasing the consumption of propulsion power.

[0284] According to the obtained tide level and tidal current velocity data, analyze the water flow conditions in different sections and at different times. Combining with the data in the propulsion power table, the propulsion power demand of the trailing suction hopper dredger under specific conditions can be initially determined. Then, consider the impact of the excavation operation on the propulsion power. During the excavation process, the ship needs to overcome the resistance of the soil and its own weight, which will increase the consumption of propulsion power. By analyzing the characteristics and requirements of the excavation operation, the propulsion power can be further adjusted and optimized.

[0285] In addition, other factors affecting the propulsion power can also be considered, such as wind direction, sea waves, etc. Although these factors are relatively small, they may also have a certain impact on the propulsion power of the ship in some cases. By comprehensively considering various factors, a more accurate and practical excavation and navigation propulsion power model of the trailing suction hopper dredger can be established, providing strong support for ship operation and management.

[0286] Step S4, calculate the drag power of the dredge head.

[0287] In the embodiment, the calculation process of the drag power of the dredge head is as follows:

[0288] Obtain the main engine power, auxiliary generator power, and corresponding construction parameters of the ship in different sections and at different times;

[0289] According to the main engine and auxiliary engine power, deduct the calculated values of the dredge pump, high-pressure flushing water, and propulsion power to obtain the power corresponding to the drag of the drag head and drag arm, and establish a relationship with the dredging speed (speed relative to the ground), that is:

[0290] ;

[0291] Calculate to obtain P 耙阻功 , and the corresponding dredging speed V C , plot the curve, and establish the fitting relationship between P 耙阻功 and the ship speed:

[0292] ;

[0293] In the formula, P 主瞬 is the instantaneous total power of the ship, that is, the main engine power, P 辅发 is the auxiliary engine power, η is the efficiency of the trailing suction hopper dredger, P 辅助 is the power of the ship's auxiliary equipment, and a, b, and c are all the fitting parameters of P 耙阻功 and the ship speed.

[0294] In actual calculation, first, it is necessary to accurately measure the main engine power P 主瞬 and the auxiliary generator power P 辅发 , and these powers can be measured by the power measurement equipment installed on the ship, or estimated according to the technical parameters and operating status of the engine. Then, calculate the dredge pump power P 轴 , the high-pressure flushing water power P G实功 , the propulsion power P C and the auxiliary equipment power P 辅助 ; the calculation of these powers can be carried out according to the methods introduced above. After obtaining each power value, add the main engine power and the auxiliary generator power, and then subtract the sum of the dredge pump, high-pressure flushing water, propulsion, and auxiliary equipment powers to obtain the power P 耙阻功 corresponding to the drag of the drag head and drag arm; then, collect the data of P 耙阻功 and the corresponding dredging speed V C . Through plotting the curve and conducting fitting analysis, the relationship between P 耙阻功 and the ship speed can be obtained. This relationship can help us better understand the variation law of the drag head resistance power with the ship speed and provide guidance for optimizing the construction process and improving efficiency.

[0295] Taking the Xin Hai Hu No. 4 as an example, calculate the drag power (average value) of the drag head and the corresponding ship's speed over the ground (average value) in the construction sections D3.0, D3.1, D3.2, D3.3, D3.4 and the construction area of the extension section respectively. Draw the curves of the drag power of the drag head and the speed over the ground, obtain the fitting formula, and establish the relationship between P 耙阻功 and the ship's speed as shown in Tables 4, 5 and Figures 9 - 14 shown below:

[0296] Table 4

[0297]

[0298] Table 5

[0299]

[0300] The physical properties of different soil types (such as shear strength, friction coefficient) significantly affect the drag of the drag head. It is necessary to consider introducing a soil quality correction coefficient k_soil and incorporating it into the drag power calculation formula. Obtain the soil type and distribution in the construction area, and combine with the "Dredging Engineering Soil Classification and Resistance Coefficient Manual". The soil classification and correction coefficient values are as Figure 15 shown below:

[0301] Multiply the soil quality correction coefficient k 土 directly into the drag resistance power formula, such as in the D3.0 section: ; x in the formula and in the figure represents V C .

[0302] Among them, the drag head resistance parameters of each ship design are shown in Table 6

[0303] Table 6

[0304]

[0305] Step S5, according to the power calculation results of steps S1 - S4, form a ship total power calculation model, input the construction status, process parameters, construction section, and construction time, calculate the instantaneous total power of the ship, and then calculate the carbon emissions

[0306] In the embodiment, input the construction status, process parameters, construction section, and construction time into the calculation model, calculate the instantaneous total power of the ship, and then calculate the carbon emissions, that is:

[0307] The instantaneous total power of the ship P 主瞬 :

[0308] ;

[0309] Table 7 Ship main engine load rate - power correspondence table

[0310]

[0311] Table 8 Correspondence Table of Main Engine Load Rate - Fuel Consumption Rate of Ships

[0312]

[0313] As shown in Table 7 and Table 8, Table 7 is the main engine load - power table of the ship, and Table 8 is the average fuel consumption under different loads of the main engine of the ship. When the instantaneous total power falls within a certain interval of the main engine power of the ship, the instantaneous fuel consumption rate of this interval is adopted. If the instantaneous emission time is t, then:

[0314] ;

[0315] In the formula, M1 is the fuel consumption, and F is the fuel consumption rate;

[0316] Table 9

[0317]

[0318] As shown in Table 9, the instantaneous carbon emissions are calculated according to the carbon dioxide emission coefficient table CFj, which is the carbon emissions of a single ship per single voyage per day:

[0319] Fuel mode:

[0320] ;

[0321] Gas mode:

[0322] ;

[0323] That is:

[0324] ;

[0325] In the formula, M1 is the total instantaneous fuel consumption, M2 is the total instantaneous gas consumption, M3 is the total instantaneous ignition oil fuel consumption, L is the LNG consumption in the gas mode, the calorific value of LNG gas is 49539 kJ / kg, and D1 is the ignition oil consumption rate in the gas mode, taking the average value of 11.4 kg / h;

[0326] In actual operation, the incomplete combustion error coefficient k is introduced to correct the emission calculation 燃烧 , that is:

[0327] ;

[0328] If the main engine power is below 50% of the rated power and in the low - load combustion stage, the combustion efficiency η 燃烧 further decreases, and k 燃烧 needs to be corrected:

[0329] ;

[0330] In the formula, α is the working condition coefficient, taking 0.3 - 0.5, and η 设计 is the combustion efficiency under the design working condition.

[0331] Step S6: Integrate the calculation model to calculate the carbon emissions during the construction period.

[0332] In the embodiment, by integrating the instantaneous carbon emissions during the construction period, the total carbon emissions during the construction period can be obtained. This requires determining the time range of the construction period and accumulating the instantaneous carbon emissions at each time point. During the integration process, various factors such as the main engine power, working hours, and fuel type need to be considered to ensure the accuracy of the calculation results;

[0333] If the main engine uses the fuel mode, by integrating the instantaneous carbon emissions during the construction period, the total carbon emissions during the construction period are obtained, that is, a construction vessel voyage includes dredging q 1. Heavy-load navigation q 2. Mud dumping q 3. Light-load navigation to the dredging area q 4. Four sub-units, count the earthwork volume of each single-vessel construction unit within a month, and obtain the average earthwork volume of the single-vessel construction unit m 土 , and then according to the earthwork volume of a single construction section M 土 , the total number of vessel units is obtained A , M 土 can be determined by geological exploration, engineering design documents or on-site measurement. The formula for the vessel unit A is as follows:

[0334] ;

[0335] Calculate the carbon emissions C 燃油单 or C 燃油单 of a single construction section. The calculation formula is as follows:

[0336] Fuel mode:

[0337] ;

[0338] In the formula, C 燃油 is the carbon emissions per vessel voyage in the fuel mode;

[0339] Substitute

[0340] ;

[0341] into , calculate the carbon emissions of the ship per day in a single construction section under the fuel mode;

[0342] Gas mode:

[0343] ;

[0344] In the formula, C 燃气 is the carbon emissions per voyage under the gas mode;

[0345] Substitute

[0346] ;

[0347] into , and calculate the carbon emissions of the ship per day in a single construction section under the gas mode.

[0348] According to the main engine bench test data of each ship, determine the fuel consumption under different loads. When the instantaneous total power falls within a certain interval of the main engine power, use the instantaneous fuel consumption in this interval for calculation. The instantaneous emission time can be determined according to the actual construction situation.

[0349] Finally, through the calculation formula of the instantaneous total fuel consumption, combined with the main engine power, working time and fuel consumption including ignition oil, calculate the instantaneous total fuel consumption. Then, according to the carbon dioxide emission coefficient table, determine the carbon dioxide emissions generated per unit of fuel consumption, and further calculate the instantaneous carbon emissions. This calculation process can help us understand the carbon emissions of the ship under different construction conditions and provide a basis for energy conservation and emission reduction.

[0350] The instantaneous carbon emissions of the ship can be calculated based on the instantaneous total fuel consumption and the corresponding emission coefficient. Different fuel types have different emission coefficients, which is due to their different chemical compositions and combustion characteristics. In actual applications, it is necessary to select the appropriate emission coefficient according to the fuel type used by the ship to ensure the accuracy and reliability of the carbon emissions calculation.

[0351] Step S7, measure the construction period of different construction sections of the waterway.

[0352] In the embodiment, according to the historical data, measure the earthwork volume of each construction section of the Yangtze River Estuary waterway, count the operation time and earthwork volume of a single voyage of different ships in a single construction section, and according to the average number of construction ships per day S 平均 and the average earthwork volume per voyage m 土 , and convert it to 26 days according to the effective working days per month, calculate the monthly earthwork volume of different ships in a certain construction section M 月 :

[0353] ;

[0354] Calculate the construction period based on the total monthly construction earthwork volume invested in different ships in this section and the measured earthwork volume of the section. T z :

[0355] ;

[0356] If the construction ships are Xinhaihu 4, Haihu 8, Xinhainiu, Xinhaixun, Haihu, then:

[0357] .

[0358] The construction conditions of different construction sections may vary, so the construction period will also be different. In order to accurately measure the construction period of different construction sections of the waterway, the following factors need to be considered:

[0359] Length and soil quality of the construction section: Longer construction sections and complex topographies and landforms may increase the construction time;

[0360] Construction technology and equipment: Different construction technologies and equipment have different efficiencies, which will affect the construction period;

[0361] Weather and sea conditions: Severe weather and sea conditions may cause construction interruptions and extend the construction period;

[0362] By comprehensively considering these factors, methods such as empirical formulas, simulation calculations, or actual measurements can be used to measure the construction periods of different construction sections of the waterway.

[0363] Step S8, calculate the carbon emissions of different construction sections and different ship types according to the obtained construction periods of different construction sections.

[0364] In the embodiment, calculate the carbon emissions per day per single ship of a single ship according to historical data C 燃油 or C 燃气 , and then, according to the number of construction ship trips A per day in the construction section, the daily carbon emissions of a single ship in this section can be calculated C 燃油单 or C 燃气单 , finally, according to the construction period T z , calculate the total carbon emissions of each ship or .

[0365] In the embodiment, the average number of construction ship trips per day of the same ship in different construction sections obtained from historical data analysis S平均 And the average earthwork volume m 土 , the carbon emissions of the same ship in different single construction sections are obtained according to the daily construction voyages of the ship C 单 , different ships are arranged for construction according to different construction sections. Based on the total earthwork volume of each construction section and the single-ship construction volume of different ships in that section, the construction voyages are calculated, and the carbon emissions of the ships in that section are accumulated

[0366] Characteristics of ship types: Parameters such as the main engine power, fuel consumption rate, and navigation speed of different ship types are different, which will affect carbon emissions

[0367] Environmental conditions of construction sections: The environmental conditions such as water flow speed, water depth, and soil quality in different construction sections are different, which will affect the operation efficiency and carbon emissions of ships

[0368] Construction techniques and equipment: Different construction techniques and equipment have different energy consumptions, which will affect carbon emissions

[0369] By measuring the carbon emissions of different sections and different ship types, it can provide a basis for energy conservation and emission reduction, and at the same time can provide a reference for the design and operation of ships

[0370] There are obvious differences in the environmental conditions such as water flow speed, water depth, and soil quality in different construction sections of the Yangtze River Estuary Deepwater Channel. These factors have an important impact on the operation efficiency and carbon emissions of ships. In sections with a relatively fast water flow speed, such as some areas of the North Passage of the Yangtze River Estuary, ships need to consume more energy to overcome the water flow resistance, resulting in an increase in the main propulsion power and a corresponding increase in carbon emissions

[0371] Water depth is also an important factor affecting carbon emissions. In sections with a relatively shallow water depth, the draft depth of the ship is relatively large, the friction between the hull and the bottom of the water increases, and at the same time the navigation resistance of the ship also increases, which makes both the main propulsion power and the drag head resistance power increase, resulting in an increase in carbon emissions

[0372] Soil quality has a significant impact on the drag head resistance and the power of the mud pump. In the silty soil area, the drag head resistance is relatively small, the density of the mud sucked by the mud pump is relatively low, and the required power is also relatively small, so the carbon emissions are relatively low. While in the sandy soil area, the drag head resistance is relatively large, and the mud pump needs to consume more energy to transport the mud, resulting in an increase in carbon emissions

[0373] There is a close relationship between the length of the construction period and the total carbon emissions. As the construction period extends, the operation time of the ship increases, and the energy consumption also increases accordingly, resulting in an increase in the total carbon emissions. Through the data analysis of the construction project, the functional relationship between the construction period and the total carbon emissions is established. The extension of the construction period not only leads to an increase in the total carbon emissions but also increases the carbon emissions per unit of earthwork volume. This is because during the extension of the construction period, factors such as the aging of the ship's equipment and the increase in maintenance costs will lead to a decrease in energy utilization efficiency, thus increasing the energy consumption and carbon emissions per unit of earthwork volume. By optimizing the construction organization and scheduling and shortening the construction period, carbon emissions can be effectively reduced. For example, reasonably arranging the operation sequence of the ships, reducing the waiting time and empty running mileage of the ships, can improve the construction efficiency and reduce the energy consumption and carbon emissions.

[0374] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating carbon emissions of a trailing suction hopper dredger, characterized in that, Including: Step S1, calculating the shaft power of the sludge pump; Step S2, calculating the shaft power of the high-pressure flush water pump; Step S3, calculating the main propulsion power of the trailing suction hopper dredger; Step S4, calculating the drag power of the dredging head; Step S5, based on the power calculation results of the above steps S1 - S4, forming a total ship power calculation model, inputting construction status, process parameters, construction section, and construction time, calculating the instantaneous total power of the ship, and then calculating carbon emissions; Step S6, integrating the calculation model to calculate the carbon emissions during the construction period; Step S7, measuring the construction periods of different construction sections of the waterway; Step S8, according to the measured construction periods of different construction sections, arranging different ships for construction in different construction sections, and calculating the total comprehensive carbon emissions of the fleet in different construction sections; In the above step S5, inputting the construction status, process parameters, construction section, and construction time into the calculation model, calculating the instantaneous total power of the ship, and then calculating carbon emissions, that is: Instantaneous total power P of the ship 主瞬 : ； P G实功 is the actual power of the high-pressure water pump, P C is the main propulsion power of the trailing suction hopper dredger; P 耙阻功 is the power corresponding to the resistance of the dredging head and the dredging arm; P 辅发 is the auxiliary machine power, and η is the propulsion efficiency of the trailing suction hopper dredger; P 辅助 is the power of the ship's auxiliary equipment; P 轴 is the shaft power of the sludge pump; Each ship refers to the fuel consumption at 50%, 75%, 80%, and 100% loads in the main engine bench test. When the instantaneous total power falls within a certain interval of the main engine power, the instantaneous fuel consumption rate of this interval is adopted, and the instantaneous emission time is t, then: ； In the formula, M1 is the fuel consumption, and F is the fuel consumption rate; Calculating the instantaneous carbon emissions according to the carbon dioxide emission coefficient table CFj: Fuel mode: ； Gas mode: That is: In the formula, M1 is the total instantaneous fuel consumption, M2 is the total instantaneous gas consumption, M3 is the total instantaneous ignition oil fuel consumption, L is the LNG consumption in the gas mode, the calorific value of LNG gas is 49539 kJ / kg, D1 is the ignition oil consumption rate in the gas mode, and the average value is taken as 11.4 kg / hh; In actual operation, introduce an incomplete combustion error coefficient to correct the emission calculation k 燃烧 , that is: If the main engine power is below 50% of the rated power and in the low-load combustion stage, the combustion efficiency η 燃烧 further decreases, and k 燃烧 needs to be corrected: ； Where α is the operating condition coefficient, taking a value of 0.3 - 0.5, and η 设计 is the combustion efficiency under the design condition.

2. The carbon emission calculation method of a trailing suction hopper dredger according to claim 1, characterized in that In the above step S1, the calculation process of the shaft power of the sludge pump is as follows: Calculating the shaft power of the sludge pump according to the calculated effective power of the sludge pump and the actual pump efficiency, and its calculation formula is as follows: ； Where P 有效 is the effective power of the sludge pump, H is the head of the sludge pump, Q1 is the displacement of the sludge pump, ρ is the density of the slurry, and g is the acceleration of gravity; Among them, ； In the formula, V is the flow velocity, and r is the radius of the discharge pipe of the sludge pump; ； In the formula, V2 is the discharge port flow velocity, V1 is the suction port flow velocity, P2 is the discharge port pressure, P1 is the suction pressure, and h is the vertical height distance between the discharge port pressure gauge and the center of the suction port of the sludge pump; The head of the sludge pump includes 4 parts. One is the velocity head, the second is the pressure head, the third is the elevation head, and the fourth is the frictional resistance loss and elbow resistance loss. Among them, In the formula, K1 and K2 are both resistance coefficients, L is the straight pipe length of the mud pipe, D is the inner diameter of the straight pipe of the mud pipe, and g is the acceleration of gravity; According to the flow rate - efficiency curve fitting formula, the actual pump efficiency is empirically selected as 0.8 of the theoretical pump efficiency, that is: where η 实际 is the actual pump efficiency of the mud pump, and η 理论 is the theoretical pump efficiency of the mud pump, which is obtained by fitting the flow rate - efficiency curve in the clear water test, and the flow velocity is the direct acquisition reading of the ship flowmeter.

3. The carbon emission calculation method for a trailing suction hopper dredger according to claim 2, wherein In the above step S2, the calculation process of the shaft power of the high-pressure flush water pump is as follows: Statistical analysis of the rotational speed, pressure, and power of the high-pressure water pump, drawing the characteristic curves of the high-pressure water pump at different rotational speeds. The characteristic curves include the flow velocity - rotational speed - head curve, the flow velocity - rotational speed - power curve, and the flow velocity - rotational speed - efficiency curve, and fitting to obtain the formula; Determining the flow rate according to the flow velocity of the high-pressure water pump, that is: ； Wherein, V G is the flow rate of the high-pressure water pump, S G is the discharge pipe diameter area of the high-pressure water pump, r G is the discharge pipe radius of the high-pressure water pump, R G is the discharge pipe diameter of the high-pressure water pump; According to the flow velocity and combining with the flow velocity - rotational speed - head curve, we get: Determining the pump efficiency discount ratio F according to the actual pressure and the theoretical pressure; ； Calculate the theoretical pressure at different rotational speeds, take the ratio with the actual pressure, obtain the pump efficiency discount ratio F at different rotational speeds, and average to get the pump efficiency discount ratio, that is: ； Where F a is the pump efficiency discount ratio of the ath group of rotational speeds, and a is the number of rotational speed groups; Determine the pipeline characteristics based on the flow rate and actual pressure, that is: The total resistance of the pipeline system consists of the following two parts Composition: ； Among them, H G静 is the static head of the elevation difference between the inlet and outlet of the pipeline, and the loss head H G损失 includes the frictional loss along the way and the local resistance loss, which is proportional to the square of the flow rate Q2, that is: ； In the formula, k is the pipeline characteristic coefficient; Furthermore, establish the pipeline characteristic equation, assuming H G静 = h, the energy difference generated by the fluid in the pipeline system due to the vertical height difference between the inlet and outlet, that is: ； The actual operating point of the pump satisfies: ； Subtract the static head h from the H of each group 泵i to obtain the corrected head: ； Fit and calculate the pipeline characteristic coefficient k, use the least squares method to fit the data, and obtain the pipeline characteristic coefficient k: ； Wherein, Q 2i is the flow rate of the high-pressure water pump at different rotational speeds, and H 泵i is the head of the high-pressure water pump at different rotational speeds; Calculate the corresponding flow rate according to different pressures and pipeline characteristics, determine the theoretical efficiency by looking up the table according to the corresponding flow velocity, determine the actual pump efficiency according to the theoretical efficiency and the pump efficiency discount ratio, determine the effective power according to the pressure and flow rate, and determine the actual shaft power according to the effective power and the actual pump efficiency, that is: That is: ； Wherein, P G实功 is the actual power of the high-pressure water pump, η G实际 is the actual pump efficiency of the high-pressure water pump, and η G理论 is the theoretical pump efficiency of the high-pressure water pump.

4. A method for calculating the carbon emissions of a trailing suction hopper dredger according to claim 3, characterized in that, In the step S3, the calculation process of the main propulsion power of the trailing suction hopper dredger is as follows: According to the principle of physics, in ship propulsion, the propulsion power is used to overcome the resistance of the ship to make the ship move forward. When the ship sails at a constant speed, the propulsion force is equal to the resistance of the ship, that is: That is: ； Wherein, P C is the main propulsion power of the trailing suction hopper dredger, R is the resistance suffered by the trailing suction hopper dredger, and V C is the speed of the trailing suction hopper dredger, R f is the frictional resistance, R w is the wave-making resistance, and R s is the form resistance; Among them, Frictional resistance R f is proportional to and specifically: ； To simplify the calculation, a friction resistance coefficient i is set, which is related to the hull roughness, wetted surface area, and Reynolds number. For trailing suction hopper dredgers, the empirical value of the friction resistance coefficient i is 0.35 - 0.

50. For low-speed ships, the wave-making resistance R w accounts for a relatively small proportion of the total resistance. For high-speed ships, the wave-making resistance R w becomes the main resistance component. When the ship speed exceeds the critical value, the wave-making resistance increases sharply, and its growth rate is much faster than that of the frictional resistance, being proportional to the square or higher power of the ship speed, i.e.: ； In the formula, n≥2, and n takes 3; To simplify the calculation, the wave-making resistance coefficient j is set such that , and the empirical value of the wave-making resistance coefficient j for trailing suction hopper dredgers ranges from 0.03 to 0.06; The ITTC empirical formula is used to calculate the form drag R s , that is: Calculate the wetted surface area S of the hull using the Holtrop formula C : ； Where ρ1 is the density of water, S C is the wetted surface area of the hull, C DS is the form drag coefficient, B is the beam, T is the draft, C B is the block coefficient of the ship, and L1 is the length between perpendiculars; The calculation formula for the block coefficient of the ship is as follows: In the formula, ∇ is the displacement volume, and Δ is the full load displacement; Furthermore, we get: ； In the formula, i is the frictional resistance coefficient and j is the wave-making resistance coefficient; Finally, we get: 。 5. The carbon emission calculation method of a trailing suction hopper dredger according to claim 4, wherein In the step S4, the calculation process of the drag power of the dredging head is as follows: Obtain the main engine power, auxiliary engine power, and corresponding construction parameters of the ship in different sections and at different times; According to the main engine and auxiliary engine power, deduct the calculated values of the mud pump, high-pressure flushing, and propulsion power, obtain the power corresponding to the drag of the dredging head and the dredging arm, and establish a relationship with the dredging speed, that is: ； Calculate P 耙阻功 , and with the corresponding dredging speed V C , plot a curve to establish the fitting relationship between P 耙阻功 and the ship speed: ； Wherein, P 主瞬 is the instantaneous total power of the ship, P 辅发 is the power of auxiliary machinery, η is the efficiency of the trailing suction hopper dredger, P 辅助 is the power of ship auxiliary equipment, and a, b, and c are all 耙阻功 fitting parameter coefficients of P and the ship speed.

6. The carbon emission calculation method of a trailing suction hopper dredger according to claim 5, wherein In step S6, the total carbon emissions during the construction period are obtained by integrating the instantaneous carbon emissions, that is, one construction vessel voyage includes dredging q 1. Heavy-load navigation q 2. Mud dumping q 3. Light-load navigation to the dredging area q 4. Four sub-units. The earthwork volume of each single-vessel construction unit within a month is counted, and the average earthwork volume of the single-vessel construction unit is obtained m 土 , and then according to the earthwork volume of a single construction section M 土 , the total number of vessel units is obtained A , M 土 It can be determined by geological exploration, engineering design documents or on-site measurement. The calculation formula for vessel unit A is as follows: ； Calculate the carbon emissions C of a single construction section 燃油单 or C 燃气单 , and the calculation formula is as follows: Fuel mode: ； where C 燃油 is the carbon emission per voyage in fuel mode; Put ； Substitute to calculate the carbon emissions of the ship per day in a single construction section under the fuel mode; Gas mode: ； where C 燃气 is the carbon emission per voyage in gas mode; Put Substitute , and calculate the carbon emissions of the ship per day in a single construction section under the gas mode.

7. A method for calculating the carbon emissions of a trailing suction hopper dredger according to claim 6, characterized in that, In the step S7, according to historical data, calculate the earthwork volume of each construction section of the Yangtze Estuary waterway, count the operation time and earthwork volume of each single ship's voyage in a single construction section, and calculate the monthly earthwork volume of different ships in a certain construction section according to the average daily construction ship times S 平均 and the average earthwork volume per ship's voyage m 土 , convert it to 26 days according to the effective working days per month, and calculate the monthly earthwork volume of different ships in a certain construction section M 月 : ； Calculate the construction period based on the total monthly construction earthwork volume invested in different vessels in this section and the measured earthwork volume of the section T z : 。 8. A method for calculating carbon emissions of a trailing suction hopper dredger according to claim 7, characterized in that, In the step S8, the carbon emission amount C of a single ship per single voyage per day is calculated according to historical data 燃油 or C 燃气 , and then according to the number of construction ships A per day in the construction section, the carbon emission amount C of a single ship per day in this section can be calculated 燃油单 or C 燃气单 , finally, according to the construction period T z , the total carbon emission amount C of each ship is calculated 燃油单 *T z or C 燃气单 *T z .

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