Deep-sea self-propelled and self-elevating offshore wind power installation vessel and design method thereof

Abstract

The invention provides a deep-sea self-propelled and self-elevating offshore wind power installation ship and a design method thereof. The installation ship comprises a main ship body, a ship body and a ship body, wherein the main ship body is in streamline design; the lifting system comprises pile legs, pile shoes, trunk and guide structures, pile holding chambers and pile holding lifting equipment, the four sets of trunk and guide structures are arranged at the four corners of the main ship body respectively, one pile leg is arranged in each trunk, the pile holding chambers and the pile holding lifting equipment are connected to the upper portions of the pile legs, and the pile shoes are connected to the bottoms of the pile legs; the length of the pile leg is greater than or equal to 130m; the hoisting capacity of the main hoisting equipment is 1600 t, the hoisting height is 175 m, the main hoisting equipment is combined with one lifting system, and a trunk and a guide structure are used as a supporting structure of the hoisting equipment; except for the occupation of the lifting equipment and the bow residential area, the rest deck surface of the main hull adopts a plane design, the area of the deck is greater than or equal to 3400m < 2 >, and the deck is reinforced according to the uniformly distributed load of 15t / m < 2 >. The sailing resistance can be reduced, and the sailing capability can be improved; the problems of operation water depth and insufficient lifting capacity are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of offshore wind power installation vessels, and in particular relates to a deep-sea self-propelled and self-elevating offshore wind power installation vessel and a design method thereof. Background Art

[0002] Renewable energy has become the dominant direction of low-carbon energy transformation in various countries, among which offshore wind power is of great significance and has obvious advantages: coastal areas have dense populations, concentrated economic activities, and high energy consumption, and nearby offshore wind power can reduce power transportation losses; offshore wind energy resources are huge and are renewable energy, which can support the clean transformation of major energy-consuming countries.

[0003] With the deepening of offshore wind energy resource exploration and the reduction of impact on offshore tourism and fisheries, offshore wind farms have a clear trend of developing in deep waters and offshore areas. Taking the "Guangdong Province Offshore Wind Power Development Plan (2017-2030)" as an example, 15 offshore wind farms are planned in offshore shallow waters with an installed capacity of more than 9 million kilowatts; 8 offshore wind farms are planned in offshore deep waters with an installed capacity of 57 million kilowatts. Early wind power installation ships were converted from crane ships or other engineering ships. They had no pile legs or had short pile legs, which could not meet the ability to install wind power equipment in deep water areas. In order to have deep-water operations, ultra-high pile legs are required, but the gantry crane height of major shipbuilding companies is lower than the pile leg height, which cannot meet the installation requirements of the pile legs.

[0004] The offshore installation environment is harsh, the installation time window is limited, and the installation efficiency of wind power equipment is required to be high; the wind turbine has many components and runs in a complex and changeable marine environment for a long time, so the installation accuracy is required to be high. Therefore, the efficiency, safety and stability of the overall installation of the wind turbine after onshore assembly and commissioning and transportation to the wind farm are optimal, which is the best solution for future offshore wind power installation. The existing wind power installation ship pile leg height is limited, the operating water depth is insufficient, and it cannot meet the needs of installing wind power equipment in deep water areas. There is no self-propulsion capability, the deck transportation capacity is weak, and it needs to be transported by other ships, which has high installation costs. The lifting capacity is insufficient and cannot meet the needs of overall hoisting of wind turbine equipment. Summary of the invention

[0005] The object of the present invention is to provide a deep-sea self-propelled and self-elevating offshore wind power installation vessel and a design method thereof that can adapt to the current offshore wind power installation.

[0006] A first aspect of the present invention provides a deep-sea self-propelled self-elevating offshore wind power installation vessel, comprising:

[0007] The main hull is of streamlined design;

[0008] The main hull is equipped with lifting equipment and a lifting system;

[0009] Lifting equipment includes main lifting equipment and auxiliary lifting equipment;

[0010] The lifting system includes pile legs, pile shoes, surrounding wells and guide structures, pile holding chambers and pile holding lifting equipment. Four sets of surrounding wells and guide structures are respectively arranged at the four corners of the main hull. A pile leg is arranged in each set of surrounding wells. The upper part of the pile leg is connected to the pile holding chamber and pile holding lifting equipment, and the bottom of the pile leg is connected to the pile shoes. The length of the pile leg is greater than or equal to 130m.

[0011] The main hoisting equipment has a lifting capacity of 1600t and a lifting height of 175m. The main hoisting equipment is combined with one of the lifting systems, using the enclosure and guide structure as the supporting structure of the hoisting equipment;

[0012] Except for the lifting equipment and the bow living area, the remaining deck surface of the main hull adopts a flat design, and the deck area is greater than or equal to 3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened.

[0013] Optionally, the pile leg comprises a truss-type pile leg, including three diagonal bracing tubes arranged in a triangle in the horizontal direction, and an inner horizontal tube connecting two adjacent diagonal bracing tubes.

[0014] A second aspect of the present invention provides a design method for a deep-sea self-propelled self-elevating offshore wind power installation vessel, which is used to design the deep-sea self-propelled self-elevating offshore wind power installation vessel of the first aspect of the present invention, and the design method comprises:

[0015] Ship shape design and super high pile leg design;

[0016] The ship design includes:

[0017] ① The main hull is designed with streamlined waterline to reduce the ship's navigation resistance, and calculations are performed on stability, freeboard, buoyancy, wind load, etc. to ensure the ship's floating state and stability. When equipped with power and auxiliary equipment of corresponding power, the ship is guaranteed to have a self-propulsion capability of about 8 knots;

[0018] ② Two sets of lifting systems are installed on both the left and right sides of the ship, a total of 4 sets of lifting systems, consisting of pile legs, pile shoes, wells and guide structures, pile holding rooms and pile holding lifting equipment;

[0019] ③ According to the operating water depth requirements, determine the pile leg length in accordance with the "Super High Pile Leg Design Method" to meet the deep water operation capacity requirements;

[0020] ④ According to the weight, size parameters and integrated transportation and hoisting requirements of the current largest 20MW wind power equipment, the main crane's lifting capacity is determined to be 1600t and the lifting height is 175m. The main crane is combined with one of the lifting systems, and the enclosure and guide structure are used as the crane support structure to ensure the crane's lifting capacity, lifting height and working radius;

[0021] ⑤Except for the lifting equipment and the bow living area, the remaining deck surface adopts a flat design, with a deck area of ​​3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened to ensure the large deck cargo capacity for transporting and hoisting two sets of 20MW wind power equipment.

[0022] Optionally, two sets of lifting systems are provided on both the left and right sides of the ship, for a total of 4 sets of lifting systems, which are composed of pile legs, pile shoes, wells and guide structures, pile holding chambers and pile holding lifting equipment, including:

[0023] a. According to the need to control the center of gravity of the ship, the lifting system must ensure that the ship and wind power equipment remain balanced during the lifting process;

[0024] b. The load on the lifting system is determined by the rated lifting load, pile leg support reaction, static and storm support loads, lifting speed, design temperature and design life;

[0025] c. Determine the power unit performance and rack shape based on the load.

[0026] Optionally, the extra-high leg design includes:

[0027] The method of lengthening the pile legs is adopted to increase the operating water depth. The length of the lengthened pile legs exceeds 130 meters, enabling the ship to operate in 75m water depth, meeting the installation needs in offshore deepwater areas and even offshore. In order to meet the requirements of ship self-lifting and lifting and installing wind power equipment and ensure the safety of the ship, the whole ship is equipped with 4 truss-type pile legs to share the weight of the ship itself and the wind power equipment, as well as the external wind load. At the same time, a pile shoe with preset grip is set at the lowest point of each pile leg, which penetrates into the seabed mud layer to ensure the stability of the ship during self-lifting operations.

[0028] Optionally, the pile leg length calculation method includes:

[0029] Pile leg height calculation formula = mud penetration depth + operating water depth + air gap + profile depth + pile holding chamber height + safety margin

[0030] Considering the requirements of deep-water operations, the operating water depth can reach 75m, and the remaining heights can be calculated based on the following conditions;

[0031] Depth of pile insertion into mud: According to the characteristics of the seabed foundation and the form of the pile shoe, the depth of pile insertion into mud is calculated and analyzed. The maximum depth of pile insertion into mud in deep water areas is 15m.

[0032] Air gap: According to the hull line shape and sea conditions, the air gap in offshore deep water areas is limited to 15m;

[0033] Moulded depth: 0 to 10m, depending on the overall design of the ship;

[0034] Height of pile holding chamber: According to performance calculation and pile holding device layout requirements, the height of pile holding chamber is 0~10m;

[0035] Safety margin: 5m;

[0036] Therefore, the length of the pile legs = 15m + 75m + 15m + 10m + 10m + 5m = 130m.

[0037] Optionally, the super-high pile leg structure strength design method includes:

[0038] The super-high pile legs make the truss span between the seabed and the ship larger after being lifted, and the strength requirements of the pile legs are higher. Therefore, a truss with a triangular cross-section is used to improve the structural stability, and it is supported on the inside by an inner horizontal tube to ensure the strength of the pile legs.

[0039] Optionally, the pile legs are made of high-strength and / or ultra-high-strength marine steel, wherein the gear conditions for jacking are made of special steel with a yield strength of not less than 690MPa, a tensile strength of not less than 770MPa, and a hardness of 240-290HB, with a thickness of about 180mm, and ensure that the longitudinal impact strength is not less than 69J and the transverse impact strength is not less than 46J during the V-notch -40℃ impact test; the main side tube is divided into two semicircles, the gear conditions are wrapped therein, and the yield strength is not less than 690MPa, the tensile strength is not less than 77 The round tube with a yield strength of not less than 555MPa and a tensile strength of not less than 625MPa is adopted for the diagonal brace tube, and the longitudinal impact strength is not less than 69J and the transverse impact strength is not less than 46J during the V-notch -40℃ impact test; the round tube with a yield strength of not less than 360MPa and a tensile strength of not less than 460MPa is adopted for the inner horizontal tube, and the impact strength is not less than 34J during the V-notch -40℃ impact test.

[0040] Optionally, the super-high pile leg installation method includes:

[0041] Each pile leg is divided into two parts, part one is 70m long, part two is about 60m long, and 4 pile legs have a total of 8 pile leg parts;

[0042] In the shipyard dock, a large gantry crane was used to hoist the components of the four pile legs, and the hoisting, pile installation, and pile leg lifting tests were carried out to ensure that the four pile legs could hold the pile and lift normally;

[0043] The ship is driven to the sea area outside the shipyard, and the water depth of the sea area must meet the operating depth requirements of large crane ships;

[0044] The pile leg components are lowered by using the ship's pile holding equipment. The top surface of the pile leg components is about 1m higher than the top of the pile holding chamber, which is convenient for subsequent construction. If necessary, in order to ensure the 1m welding construction space, the pile legs can be inserted into the seabed mud layer;

[0045] Using a crane ship, the second part of the four pile legs is hoisted onto the top of the first part in sequence. After the first and second parts are aligned and fixed, welding is performed at sea.

[0046] After the four parts are welded separately, pile legs 1 to 4 are installed.

[0047] Optionally, if the performance of the crane vessel is limited, the component two of the four pile legs can be split into two components and installed in sequence at sea.

[0048] The beneficial effects brought by the present invention are as follows:

[0049] It can be seen from the above scheme that the embodiment of the present invention provides a deep-sea self-propelled and self-elevating offshore wind power installation vessel, in which the main hull is streamlined, which can reduce navigation resistance and improve navigation capability; the pile leg length is greater than or equal to 130m, which solves the problem of limited pile leg height and insufficient operating water depth of the wind power installation vessel; the main hoisting equipment has a lifting capacity of 1600t and a lifting height of 175m, which solves the problem of insufficient lifting capacity and inability to meet the overall lifting requirements of wind turbine equipment; except for the lifting equipment and the bow living area, the remaining deck surface of the main hull adopts a flat design, and the deck area is greater than or equal to 3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened, which solves the problem of weak deck transportation capacity, the need for transportation by other ships, and high installation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic structural diagram showing a deep-sea self-propelled and self-elevating offshore wind power installation vessel from a first perspective according to an embodiment of the present invention;

[0051] Figure 2 A schematic structural diagram showing a deep-sea self-propelled and self-elevating offshore wind power installation vessel from a second perspective according to an embodiment of the present invention;

[0052] Figure 3 A structural diagram of a deep-sea self-propelled and self-elevating offshore wind power installation vessel according to an embodiment of the present invention;

[0053] Figure 4 A pile leg arrangement diagram of a deep-sea self-propelled and self-elevating offshore wind power installation vessel according to an embodiment of the present invention is shown;

[0054] Figure 5 A side view of a pile leg of a deep-sea self-propelled and self-elevating offshore wind power installation vessel according to an embodiment of the present invention;

[0055] Figure 6 A top view of the pile legs of a deep-sea self-propelled and self-elevating offshore wind power installation vessel according to an embodiment of the present invention is shown.

[0056] In the figure, 1. main hoisting equipment; 2. main hull; 3. auxiliary hoisting equipment; 4. pile holding room and pile holding lifting equipment; 5. surrounding well and guide structure; 6. pile legs; 7. diagonal bracing pipes; 8. pile shoes; 91. outer main side pipe; 92. inner main side pipe; 10. tooth condition; 11. inner horizontal pipe. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The present invention aims to solve the problem that early wind power installation ships had no or weak self-propulsion ability and limited lifting capacity. These small ships were prone to poor maneuverability and positioning performance, could not operate when the wind was slightly strong, and had low efficiency, and could not meet new installation requirements. A self-propelled deep-sea offshore wind power installation ship with self-elevation function, deep-water operation capability, high lifting capacity, and large deck cargo capacity was invented to achieve integrated transportation of offshore wind turbines from the dock base to the deep-water sea area, complete the installation of offshore wind power equipment of 20MW and below, and solve the installation problem of its super-high pile leg 6.

[0059] See also Figures 1 to 6 The first aspect of the present invention provides a deep-sea self-propelled self-elevating offshore wind power installation vessel, comprising:

[0060] The main hull 2 ​​is of streamlined design;

[0061] The main hull 2 ​​is equipped with a lifting device and a lifting system;

[0062] The lifting equipment includes a main lifting equipment 1 and an auxiliary lifting equipment 3;

[0063] The lifting system includes pile legs 6, pile shoes 8, surrounding wells and guide structures 5, pile holding chambers and pile holding lifting equipment 4. Four groups of surrounding wells and guide structures 5 are respectively arranged at the four corners of the main hull 2. A pile leg 6 is arranged in each group of surrounding wells. The upper part of the pile leg 6 is connected to the pile holding chamber and pile holding lifting equipment 4, and the bottom of the pile leg 6 is connected to the pile shoe 8; the length of the pile leg 6 is greater than or equal to 130m; the pile leg 6 is a truss-type pile leg, including three diagonal support pipes 7 arranged in a triangle in the horizontal direction, and an inner horizontal pipe 11 connecting two adjacent diagonal support pipes 7.

[0064] The main hoisting equipment 1 has a lifting capacity of 1600t and a lifting height of 175m. The main hoisting equipment 1 is combined with one of the lifting systems, and the enclosure and guide structure 5 are used as the supporting structure of the hoisting equipment;

[0065] Except for the lifting equipment and the bow living area, the remaining deck surface of the main hull 2 ​​is designed to be flat, and the deck area is greater than or equal to 3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened.

[0066] A second aspect of the present invention provides a design method for a deep-sea self-propelled self-elevating offshore wind power installation vessel, which is used to design the deep-sea self-propelled self-elevating offshore wind power installation vessel of the first aspect of the present invention, and the design method comprises:

[0067] Ship shape design and super high pile leg 6 design;

[0068] The ship design includes:

[0069] ①Combination Figure 1 and Figure 2 The main hull 2 ​​is designed with streamlined waterline to reduce the ship's navigation resistance, and calculations are performed on stability, freeboard, buoyancy, wind load, etc. to ensure the ship's floating state and stability. When equipped with power and auxiliary equipment of corresponding power, the ship is guaranteed to have a self-propulsion capability of about 8 knots;

[0070] ②Combination Figure 3 and Figure 4 Two sets of lifting systems are arranged on both the left and right sides of the ship, namely, a total of four lifting systems, which are composed of pile legs 6, pile shoes 8, surrounding wells and guide structures 5, pile holding chambers and pile holding lifting equipment 4;

[0071] a. According to the need to control the center of gravity of the ship, the lifting system must ensure that the ship and wind power equipment remain balanced during the lifting process;

[0072] b. The load on the lifting system is determined by the rated lifting load, pile leg support reaction, static and storm support loads, lifting speed, design temperature, design life, etc.;

[0073] c. Determine the power unit performance and rack shape based on the load.

[0074] ③ According to the operating water depth requirements, determine the length of pile leg 6 in accordance with the "Super High Pile Leg Design Method" below to meet the deep water operation capacity requirements;

[0075] ④ According to the weight, size parameters and integrated transportation and hoisting requirements of the current largest 20MW wind power equipment, the main crane's lifting capacity is determined to be 1600t and the lifting height is 175m. The main crane is combined with one of the lifting systems, and the enclosure and guide structure 5 are used as the crane support structure to ensure the crane's lifting capacity, lifting height and working radius;

[0076] ⑤Except for the lifting equipment and the bow living area, the remaining deck surface adopts a flat design, with a deck area of ​​about 3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened to ensure the large deck cargo capacity for transporting and hoisting two sets of 20MW wind power equipment.

[0077] The design of super-high leg 6 includes:

[0078] The method of lengthening the pile legs 6 is adopted to increase the operating water depth. The length of the lengthened pile legs 6 exceeds 130 meters, so that the ship has the ability to operate in 75m water depth, meeting the installation needs in offshore deepwater areas and even offshore. In order to meet the requirements of ship self-lifting and lifting and installing wind power equipment and ensure the safety of the ship, the whole ship is equipped with 4 truss pile legs to share the weight of the ship itself and the wind power equipment, and the external wind load. At the same time, a pile shoe 8 with preset grip is set at the lowest point of each pile leg 6, which penetrates into the seabed mud layer to ensure the stability of the ship during self-lifting operations.

[0079] Combination Figure 3 The leg length calculation method includes:

[0080] Pile leg height = mud penetration depth + operating water depth + air gap + profile depth + pile holding chamber height + safety margin

[0081] Considering the requirements of deep-water operations, the operating water depth can reach 75m, and the remaining heights can be calculated based on the following conditions;

[0082] Depth of pile insertion into mud: According to the characteristics of the seabed foundation and the form of the pile shoe 8, the depth of pile insertion into mud is calculated and analyzed. The maximum depth of pile insertion into mud in deep water areas is 15m.

[0083] Air gap: According to the hull line shape and sea conditions, the air gap in offshore deep water areas is limited to 15m;

[0084] Moulded depth: 0 to 10m, depending on the overall design of the ship;

[0085] Height of pile holding chamber: According to performance calculation and pile holding device layout requirements, the height of pile holding chamber is 0~10m;

[0086] Safety margin: 5m for the total length;

[0087] Therefore, the pile leg length = 15m + 75m + 15m + 10m + 10m + 5m = 130m.

[0088] Combination Figures 4 to 6 , the structural strength design method of super-high pile leg 6 includes:

[0089] The super-high pile legs 6 make the truss span between the seabed and the ship larger after jacking, and the strength requirements of the pile legs 6 are higher. Therefore, a truss with a triangular cross-section is used to improve the structural stability, and the inner horizontal pipe 11 is used to support the inner side to ensure the strength of the pile legs 6.

[0090] Furthermore, the pile legs 6 are made of high-strength and ultra-high-strength marine steel, wherein the gear condition 10 for jacking is made of special steel with a yield strength of not less than 690MPa, a tensile strength of not less than 770MPa, and a hardness between 240 and 290HB, with a thickness of about 180mm, and ensures that the longitudinal impact strength is not less than 69J and the transverse impact strength is not less than 46J during the V-notch -40°C impact test; the main side pipe is divided into two semicircles, including an outer main side pipe 91 and an inner main side pipe 92, the outer main side pipe 91 and the inner main side pipe 92 are arranged relatively to wrap the gear condition 10 therein, and a round pipe (diameter of about 1.5mm) with a yield strength of not less than 690MPa and a tensile strength of not less than 770MPa is used. 500mm, thickness of about 80mm), and ensure that the longitudinal impact strength is not less than 69J, and the transverse impact strength is not less than 46J during the V-notch -40℃ impact test; the diagonal brace tube 7 adopts a round tube (diameter 273.1mm, thickness 18.3mm) with a yield strength of not less than 555MPa and a tensile strength of not less than 625MPa, and ensures that the impact strength is not less than 55J during the V-notch -40℃ impact test; the inner horizontal tube 11 adopts a round tube (diameter 152.4mm, thickness 10mm) with a yield strength of not less than 360MPa and a tensile strength of not less than 460MPa, and ensures that the impact strength is not less than 34J during the V-notch -40℃ impact test.

[0091] Optionally, the super-high pile leg installation method includes:

[0092] The total length of an offshore wind power installation vessel is close to 200m, which is a large ship and usually needs to be built in a large shipyard. However, the effective lifting height of the large lifting equipment gantry crane of major domestic shipbuilding companies is currently about 75m to 80m, which cannot meet the lifting and installation requirements of the 130m long pile leg 6.

[0093] Each pile leg 6 is divided into two parts, with part one being 70m long and part two being about 60m long, and a total of eight pile leg 6 parts are obtained for four pile legs 6; in the dock of the shipyard, parts one of the four pile legs 6 are hoisted by a large gantry crane respectively, and hoisting, pile insertion and installation, and pile leg lifting and lowering tests are carried out to ensure that the four pile legs 6 can hold the pile and lift normally; the ship is driven to the sea area outside the shipyard, and the water depth of the sea area must meet the operating depth requirements of large crane ships; the pile leg 6 part one is lowered by the ship's pile holding equipment, and the top surface of the pile leg 6 part one is about 1m higher than the top of the pile holding chamber, which is convenient for subsequent construction; if necessary, in order to ensure this 1m welding construction space, the pile leg 6 can be inserted into the seabed mud layer; the crane ship is used to hoist the parts two of the four pile legs 6 in sequence above the parts one, and after the parts one and two are aligned and fixed, they are welded at sea; after the four parts two are respectively welded, the installation of pile legs 6 No. 1 to 4 is completed. If the performance of the crane vessel is limited, the second component of the four pile legs 6 can be split into two components and installed in sequence at sea.

[0094] The ship type of the present invention has self-propelled and self-elevating functions, and has deep-water operation capability, high lifting capacity, and large deck cargo capacity, realizing integrated transportation of offshore wind turbines from the dock base to deep-water areas, and completing the installation of offshore wind power equipment of 20MW and below. It solves the manufacturing and installation problems of its super-high pile legs 6.

[0095] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A deep-sea self-propelled and self-elevating offshore wind power installation vessel, characterized in that: include: A main hull, wherein the main hull is of streamlined design; The main hull is equipped with a lifting device and a lifting system; The lifting equipment includes main lifting equipment and auxiliary lifting equipment; The lifting system comprises pile legs, pile shoes, enclosures and guide structures, pile holding chambers and pile holding lifting equipment. Four groups of enclosures and guide structures are respectively arranged at the four corners of the main hull. One pile leg is arranged in each group of enclosures. The upper part of the pile leg is connected to the pile holding chamber and the pile holding lifting equipment, and the bottom of the pile leg is connected to the pile shoes. The length of the pile leg is greater than or equal to 130m. The main hoisting equipment has a lifting capacity of 1600t and a lifting height of 175m. The main hoisting equipment is combined with one of the lifting systems, and the enclosure and guide structure are used as the supporting structure of the hoisting equipment; Except for the lifting equipment and the bow living area, the remaining deck surface of the main hull adopts a flat design, and the deck area is greater than or equal to 3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened.

2. The deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 1 is characterized in that: The pile legs include truss-type pile legs, including three diagonal bracing tubes arranged in a triangle along the horizontal direction, and an inner horizontal tube connecting two adjacent diagonal bracing tubes.

3. A method for designing a deep-sea self-propelled self-elevating offshore wind power installation vessel, used for designing a deep-sea self-propelled self-elevating offshore wind power installation vessel as claimed in claim 1 or 2, characterized in that: The design method comprises: Ship shape design and super high pile leg design; The ship design includes: 1) The main hull is designed with a streamlined waterline to reduce the ship's navigation resistance, and calculations are performed on stability, freeboard, buoyancy, wind load, etc. to ensure the ship's buoyancy and stability. When equipped with power and auxiliary equipment of corresponding power, the ship is guaranteed to have a self-propulsion capability of about 8 knots; 2) Two sets of lifting systems are installed on both the left and right sides of the ship, a total of 4 lifting systems, consisting of pile legs, pile shoes, wells and guide structures, pile holding rooms and pile holding lifting equipment; 3) According to the operating water depth requirements, the pile leg length is determined in accordance with the "Super High Pile Leg Design Method" to meet the deep water operation capacity requirements; 4) According to the weight, size parameters and integrated transportation and hoisting requirements of the current largest 20MW wind power equipment, the main crane's lifting capacity of 1600t and lifting height of 175m are determined. The main crane is combined with one of the lifting systems, and the enclosure and guide structure are used as the crane support structure to ensure the crane's lifting capacity, lifting height and working radius; 5) Except for the lifting equipment and the bow living area, the remaining deck surface adopts a flat design, with a deck area of ​​3400m 2 , Deck according to 15t / m 2 The uniformly distributed load setting is strengthened to ensure the large deck cargo capacity for transporting and hoisting two sets of 20MW wind power equipment.

4. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 3 is characterized in that: The said two sets of lifting systems are arranged on both the left and right sides of the ship, a total of 4 sets of lifting systems, which are composed of pile legs, pile shoes, enclosures and guide structures, pile holding chambers and pile holding lifting equipment, including: a. According to the need to control the center of gravity of the ship, the lifting system must ensure that the ship and wind power equipment remain balanced during the lifting process; b. The load on the lifting system is determined by the rated lifting load, pile leg support reaction, static and storm support loads, lifting speed, design temperature and design life; c. Determine the power unit performance and rack shape based on the load.

5. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 3 is characterized in that: The super-high pile leg design includes: The method of lengthening the pile legs is adopted to increase the operating water depth. The length of the lengthened pile legs exceeds 130 meters, enabling the ship to operate in 75m water depth, meeting the installation needs in offshore deepwater areas and even offshore. In order to meet the requirements of ship self-lifting and lifting and installing wind power equipment and ensure the safety of the ship, the whole ship is equipped with 4 truss-type pile legs to share the weight of the ship itself and the wind power equipment, as well as the external wind load. At the same time, a pile shoe with preset grip is set at the lowest point of each pile leg, which penetrates into the seabed mud layer to ensure the stability of the ship during self-lifting operations.

6. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 5 is characterized in that: The pile leg length calculation method includes: Pile leg height calculation formula = mud penetration depth + operating water depth + air gap + profile depth + pile holding chamber height + safety margin Considering the requirements of deep-water operations, the operating water depth can reach 75m, and the remaining heights can be calculated based on the following conditions; Depth of pile insertion into mud: According to the characteristics of the seabed foundation and the form of the pile shoe, the depth of pile insertion into mud is calculated and analyzed. The maximum depth of pile insertion into mud in deep water areas is 15m. Air gap: According to the hull line shape and sea conditions, the air gap in offshore deep water areas is limited to 15m; Moulded depth: 0 to 10m, depending on the overall design of the ship; Height of pile holding chamber: According to performance calculation and pile holding device layout requirements, the height of pile holding chamber is 0~10m; Safety margin: 5m; Therefore, the leg length = 15m + 75m + 15m + 10m + 10m + 5m = 130m.

7. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 5 is characterized in that: The super-high pile leg structure strength design method comprises: The super-high pile legs make the truss span larger after the seabed and the ship are lifted, and the strength requirements of the pile legs are higher. Therefore, a truss with a triangular cross-section is used to improve the structural stability, and the inner horizontal tube is used to support the inner side to ensure the strength of the pile legs.

8. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 7 is characterized by: The pile legs are made of high-strength and / or ultra-high-strength marine steel, wherein the gear conditions for jacking are made of special steel with a yield strength of not less than 690MPa, a tensile strength of not less than 770MPa, and a hardness between 240 and 290HB, with a thickness of about 180mm, and ensure that the longitudinal impact strength is not less than 69J and the transverse impact strength is not less than 46J during the V-notch -40℃ impact test; the main side tube is divided into two semicircles, which wrap the gear conditions therein, and the yield strength is not less than 690MPa, the tensile strength is not less than 770MPa, and the hardness is between 240 and 290HB. MPa, and ensure that the longitudinal impact strength is not less than 69J, and the transverse impact strength is not less than 46J during the V-notch -40℃ impact test; the diagonal brace tube adopts a round tube with a yield strength of not less than 555MPa and a tensile strength of not less than 625MPa, and ensure that the impact strength is not less than 55J during the V-notch -40℃ impact test; the inner horizontal tube adopts a round tube with a yield strength of not less than 360MPa and a tensile strength of not less than 460MPa, and ensure that the impact strength is not less than 34J during the V-notch -40℃ impact test.

9. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 8 is characterized in that: The super-high pile leg installation method comprises: Each pile leg is divided into two parts, part one is 70m long, part two is about 60m long, and 4 pile legs have a total of 8 pile leg parts; In the shipyard dock, a large gantry crane was used to hoist the components of the four pile legs, and the hoisting, pile installation, and pile leg lifting tests were carried out to ensure that the four pile legs could hold the pile and lift normally; The ship is driven to the sea area outside the shipyard, and the water depth of the sea area must meet the operating depth requirements of large crane ships; The pile leg components are lowered by using the ship's pile holding equipment. The top surface of the pile leg components is about 1m higher than the top of the pile holding chamber, which is convenient for subsequent construction. If necessary, in order to ensure the 1m welding construction space, the pile legs can be inserted into the seabed mud layer; Using a crane ship, the second part of the four pile legs is hoisted onto the top of the first part in sequence. After the first and second parts are aligned and fixed, welding is performed at sea. After the four parts are welded separately, pile legs 1 to 4 are installed.

10. The design method of the deep-sea self-propelled self-elevating offshore wind power installation vessel according to claim 9, characterized in that: If the performance of the crane vessel is limited, component two of the four pile legs can be split into two components and installed one by one at sea.

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