Marine air lubrication system based on main engine flue gas waste heat recovery

Abstract

This utility model discloses a marine air lubrication system based on the reuse of waste heat from main engine flue gas. It includes: a waste heat-steam conversion unit that converts the waste heat from the main engine and waste gas turbine compressor into hot steam via a waste gas box, a waste gas boiler heat exchanger, and a waste gas boiler; a steam-mechanical energy-electric energy conversion unit that uses a steam turbine to drive a compressor to produce compressed air, with the remaining mechanical energy converted into electrical energy by a motor-generator to feed into the ship's electrical grid or into mechanical energy to drive the compressor; a compressed air supply unit that delivers compressed air to a bottom release device to form a drag-reducing air film; a steam waste heat cascade utilization unit that supplies low-pressure steam to ship heat users, which is condensed by a steam condenser; a condensate recovery unit that collects condensate and returns it to the waste gas boiler to complete the working fluid cycle; and an intelligent integrated control unit that uses a sensor network and control unit to achieve adaptive system operation. This utility model solves the problems of cost and energy consumption bottlenecks, system fragmentation, and energy waste.

Description

Technical Field

[0001] This utility model relates to the fields of marine engineering and energy conservation and emission reduction technology, and in particular to a marine air lubrication system based on the reuse of waste heat from main engine flue gas. Background Technology

[0002] Marine air lubrication technology, by forming a stable air film on the hull, effectively reduces frictional resistance between the hull and water, and is one of the key technologies for energy conservation and carbon reduction in the shipping industry. However, the large-scale application of this technology has long been constrained by a stable and economical high-pressure air supply solution.

[0003] Currently, the mainstream gas supply solutions in the industry and their existing technical shortcomings are as follows:

[0004] Independent air compressor supply solution: This solution involves configuring one or more high-power electric air compressors separately for the air lubrication system. This solution has significant drawbacks: (a) High initial investment costs, with substantial expenses for purchasing high-power air compressors and associated power distribution and cooling equipment; (b) Extremely high daily operating energy consumption, as the air compressor is one of the main power-consuming devices on board, significantly increasing fuel consumption and operating costs; (c) Impact on the design of the ship's electrical system, often requiring an expansion of the main generator capacity or the addition of a dedicated generator to meet sudden load increases, further increasing construction costs and system complexity; (d) Wasteful equipment idleness, as the air lubrication system is not in operation during low-speed periods, port calls, or berthing, leaving the expensive air compressors completely idle and resulting in low asset utilization.

[0005] Main Engine Energy Diversion and Air Supply Schemes: To overcome the shortcomings of independent energy supply, two improvement approaches have emerged that attempt to utilize the main engine's own energy. First, a portion of compressed air is diverted from the scavenging manifold after the main engine turbocharger. With this scheme, the scavenging air volume is already at a critical demand level during main engine operation; diversion would lead to insufficient main engine intake, affecting combustion efficiency and power output. Furthermore, the scavenging manifold pressure needs to match the requirements of the air lubrication system, making it difficult to adequately meet the needs of multiple users and operating conditions. Second, the low-pressure flue gas after the turbocharger is utilized. The main drawback of this scheme is that the pressure of the flue gas after turbine expansion is close to atmospheric pressure, far below the hydrostatic pressure at the hull bottom (typically requiring a gauge pressure of 0.3-0.6 MPa), making it impossible to effectively inject the gas into the water to form a lubricating film.

[0006] In summary, existing technical solutions are extremely costly and energy-intensive, resulting in poor economic efficiency. They fail to achieve deep integration and cascade utilization of ship energy and cannot meet the core requirements of air lubrication systems for stable air source pressure and flow. Utility Model Content

[0007] This invention provides a marine air lubrication system based on the reuse of waste heat from main engine flue gas, in order to overcome the above-mentioned technical problems.

[0008] To achieve the above objectives, the technical solution of this utility model is as follows:

[0009] A marine air lubrication system based on the reuse of waste heat from main engine flue gas includes: a main engine, a waste gas turbine compressor, a marine electrical grid, a waste heat-steam conversion unit, a steam-mechanical energy-electric energy conversion unit, a compressed air supply unit, a steam waste heat cascade utilization unit, a condensate recovery unit, and an intelligent integrated control unit.

[0010] The waste heat-steam conversion unit is connected to the main unit and the waste gas turbine compressor, and includes a waste gas box, a waste gas boiler heat exchanger and a waste gas boiler; it is used to receive the waste heat of the flue gas discharged from the main unit and the waste gas turbine compressor, heat the boiler feedwater in the waste gas boiler, and convert the boiler feedwater into hot steam.

[0011] The steam-mechanical energy-electric energy conversion unit, connected to the waste heat-steam conversion unit and the ship's electrical grid, includes a steam turbine, a compressor, and a motor-generator integrated unit; it is used to receive the hot steam output from the waste heat-steam conversion unit, output mechanical energy through steam expansion, compress the ambient air drawn in by the mechanical energy to generate compressed air, and convert the remaining mechanical energy into electrical energy to supply power to the ship's electrical grid or convert electrical energy into mechanical energy to assist in the production of compressed air;

[0012] The compressed air supply unit is connected to the steam-mechanical-electric energy conversion unit and includes a bottom release device for supplying compressed air to the bottom of the ship to form an air film.

[0013] The waste steam utilization unit is connected to the steam-mechanical-electric energy conversion unit and includes a ship heat user and a steam condenser; it is used to receive the low-pressure steam output by the steam-mechanical-electric energy conversion unit after it has done work, to provide a heat source for the ship heat user, and to condense the excess low-pressure steam to generate condensate.

[0014] The condensate recovery unit is connected to the steam waste heat cascade utilization unit and the waste heat-steam conversion unit. It includes a condensate collection cabinet for collecting the condensate output from the steam waste heat cascade utilization unit and transmitting it to the feedwater side of the waste gas boiler in the waste heat-steam conversion unit to complete the working fluid circulation.

[0015] The intelligent integrated control unit includes a sensor network, a control unit, and a motor-generator integrated load control unit; the sensor network is used to collect ship operating parameters, the control unit is electrically connected to both the sensor network and the motor-generator integrated load control unit, and the motor-generator integrated load control unit is controlled and connected to the motor-generator integrated unit in the steam-mechanical energy-electric energy conversion unit.

[0016] Furthermore, in the waste heat-steam conversion unit,

[0017] The input end of the exhaust gas box is connected to the exhaust port of the main unit and is used to receive the exhaust gas from the main unit;

[0018] The first flue gas output end of the exhaust gas box is connected to the input end of the exhaust gas boiler heat exchanger through the exhaust gas discharge pipeline, and the second flue gas output end is connected to the flue gas inlet of the exhaust gas turbine compressor through the exhaust gas turbine release pipeline, which is used to distribute the exhaust gas of the main unit to the exhaust gas turbine compressor and the exhaust gas boiler heat exchanger.

[0019] The output end of the waste gas boiler heat exchanger is connected to the flue gas side and the feedwater side of the waste gas boiler, and is used to heat the boiler feedwater in the waste gas boiler through the waste gas boiler heat exchanger and convert it into hot steam with the ability to do work.

[0020] The feedwater end of the waste gas boiler receives boiler feedwater through the waste gas boiler water supply pipeline, and the steam output end is connected to the input end of the steam-mechanical energy-electric energy conversion unit through the waste gas boiler steam supply pipeline, which is used to transport hot steam to the steam-mechanical energy-electric energy conversion unit.

[0021] The output end of the exhaust gas turbo compressor is connected to the input end of the main unit through the main unit scavenging pipeline, which is used to scaveng the main unit with the generated compressed air and transmit the remaining exhaust gas to the exhaust gas boiler heat exchanger.

[0022] Furthermore, in the steam-mechanical energy-electric energy conversion unit,

[0023] The steam turbine inlet is connected to the steam supply pipeline of the waste gas boiler to receive hot steam from the waste gas boiler and expand it to do work, outputting mechanical energy; the output shaft is connected to the input shaft of the compressor and the integrated motor generator through a transmission mechanism to drive the compressor to compress air and drive the integrated motor generator to convert mechanical energy into electrical energy.

[0024] The compressor's air inlet is connected to the ambient atmosphere for drawing in air; its air outlet is connected to the compressed air supply unit via an air lubrication supply main pipe for outputting compressed air.

[0025] The integrated motor-generator is electrically connected to the ship's electrical grid and is used to input electrical energy into the ship's electrical grid to supply power to the load users of the ship's electrical grid in the power generation mode, or to obtain electrical energy from the ship's generator in the ship's electrical grid to assist in driving the compressor in the electric mode.

[0026] Furthermore, in the compressed air supply unit,

[0027] The output end of the air lubrication supply main is connected to the air distribution pipeline arranged along the bottom of the ship to distribute compressed air to different areas of the bottom of the ship.

[0028] The air distribution pipeline is connected to the bottom release device located at the bottom of the ship, which is used to release compressed air to the surface of the hull to form a drag-reducing air lubrication layer.

[0029] Furthermore, in the steam waste heat cascade utilization unit,

[0030] The exhaust port of the steam turbine is connected to the steam inlet of the ship's heat user through the first branch of the low-pressure steam pipeline of the waste gas boiler, and is used to provide low-pressure steam for heating to the ship's heat user.

[0031] The exhaust port of the steam turbine is connected to the steam inlet of the steam condenser through the second branch of the low-pressure steam pipeline of the waste gas boiler, which is used to condense excess low-pressure steam and maintain stable pipeline pressure.

[0032] The condensate outlets of both the ship's heat users and the steam condenser are connected to the condensate recovery unit.

[0033] Furthermore, in the condensate recovery unit,

[0034] The input end of the condensate collection cabinet is connected to the condensate outlet of the ship's heat user and the steam condenser respectively through the exhaust gas boiler steam condensate pipeline, for collecting the generated condensate;

[0035] The output end of the condensate collection cabinet is connected to the waste gas boiler through a condensate return pipeline, so as to send the condensate back to the waste gas boiler and complete the working fluid circulation.

[0036] Furthermore, in the intelligent integrated control unit:

[0037] The sensor network includes a main engine load sensor for monitoring the main engine load, a speed sensor for monitoring the ship's speed, a hydrostatic pressure sensor for monitoring the hydrostatic pressure at the bottom of the ship, and an air supply pressure sensor for monitoring the pressure of the air lubrication supply manifold.

[0038] The control unit is connected to the sensor network and electrically connected to the steam inlet regulating valve and the motor-generator integrated load control unit located on the steam supply pipeline of the waste gas boiler. It sends control signals to control the motor-generator integrated unit to enter the power generation mode or electric mode through the motor-generator integrated load control unit.

[0039] Beneficial effects: This utility model provides a marine air lubrication system based on the reuse of waste heat from main engine flue gas, which has the following advantages:

[0040] 1. This utility model achieves "zero additional energy consumption" and "high economy," solving the bottlenecks of cost and energy consumption: This utility model creatively uses the waste heat of the main engine flue gas as the only initial energy source of the system, and ultimately drives the compressor through the path of "waste heat → steam → mechanical energy." Therefore, the operation of the air lubrication system basically does not consume the expensive electrical energy of the ship's electrical grid. Its main operating cost (waste heat of flue gas) was originally discarded or inefficiently utilized, resulting in near-zero cost. This greatly improves its economic efficiency throughout its entire life cycle, realizes the multiplier effect of "using waste heat to save energy," and significantly shortens the investment payback period.

[0041] 2. It has achieved deep integration of ship energy and "temperature-matched, cascaded utilization" of energy, solving the problems of system fragmentation and energy waste:

[0042] This invention deeply embeds the air lubrication system into the ship's existing energy chain, connecting the main engine flue gas system, the exhaust gas boiler steam system, the low-pressure steam heating system, and the ship's electrical network, achieving a high degree of cross-system synergy. The system realizes multi-stage conversion of flue gas thermal energy → steam mechanical energy → compressed air energy / electrical energy, as well as the reuse of low-pressure thermal energy after steam expands and performs work. By deeply coupling the air lubrication system with the ship's existing exhaust gas boiler, low-pressure steam network, and electrical system, it breaks down the barriers between traditional systems and achieves synergistic optimization of "heat-work-electricity-gas".

[0043] 3. This utility model provides a stable, reliable, and pressure-matched high-quality air source, meeting the core requirements of air lubrication:

[0044] This invention utilizes a dedicated compressor driven by a steam turbine to stably generate (adjustable) high-pressure air, with a pressure far exceeding the hydrostatic pressure at the bottom of the ship. This ensures effective injection of compressed air and the formation of a stable air film, fundamentally solving the problem that the "low-pressure flue gas utilization scheme" is completely infeasible due to insufficient pressure.

[0045] The system's air supply is completely independent of the main unit's scavenging system, supplied by a dedicated compressor. This completely avoids the serious defects caused by diverting air from the scavenging manifold, such as insufficient main unit air intake, affecting combustion efficiency and power output. It ensures the safe, efficient, and stable operation of the main unit, while also meeting the core requirements of air lubrication for air supply "pressure" and "flow independence." Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A schematic diagram of a ship air lubrication system based on the reuse of waste heat from main engine flue gas, provided by this utility model;

[0048] In the diagram, 1. Main engine; 2. Exhaust gas box; 3. Exhaust gas boiler heat exchanger; 4. Exhaust gas boiler; 5. Exhaust gas turbine compressor; 6. Control unit; 7. Steam turbine; 8. Compressor; 9. Integrated generator set; 10. Steam condenser; 11. Condensate collection tank; 12. Bottom release device; 13. Ship's heat user; 14. Ship's electrical grid load user; 15. Ship's generator; 16. Ship's electrical grid; 17. Integrated generator set load control unit; L1. Exhaust gas discharge pipeline; L2. Exhaust gas turbine release pipeline; L3. Compressed air to main engine scavenging pipeline; L4. Exhaust gas boiler water supply pipeline; L5. Exhaust gas boiler steam supply pipeline; L6. L7, Low-pressure steam pipeline of the exhaust gas boiler; L8, condensate pipeline of the exhaust gas boiler; L9, condensate return pipeline; L10, main air supply pipeline for air lubrication; P1, exhaust gas boiler water supply pump; P2, condensate return pump; T1, main air supply flow meter; T2, air supply pressure sensor; T3, static water pressure sensor; T4, main engine load sensor; T5, speed sensor; V1, flue gas regulating valve; V2, flue gas regulating valve; V3, boiler water supply regulating valve; V4, boiler steam regulating valve; V5, lubrication air regulating valve; V6, low-pressure steam regulating valve; V7, low-pressure steam regulating valve; V8, bypass regulating valve. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0050] This embodiment provides a marine air lubrication system based on the reuse of waste heat from main engine flue gas, such as... Figure 1 As shown, it includes: main unit 1, exhaust gas turbine compressor 5, marine electrical grid 16, waste heat-steam conversion unit, steam-mechanical energy-electric energy conversion unit, compressed air supply unit, steam waste heat cascade utilization unit, condensate recovery unit, and intelligent integrated control unit;

[0051] The waste heat-steam conversion unit is connected to the main unit 1 and the waste gas turbine compressor 5, and includes a waste gas box 2, a waste gas boiler heat exchanger 3 and a waste gas boiler 4; it is used to receive the waste heat of the flue gas discharged from the main unit 1 and the waste gas turbine compressor 5, heat the boiler feedwater in the waste gas boiler 4, and convert the boiler feedwater into hot steam.

[0052] The steam-mechanical energy-electric energy conversion unit is connected to the waste heat-steam conversion unit and the ship's electrical grid 16. It includes a steam turbine 7, a compressor 8, and a motor-generator integrated unit 9. It is used to receive the hot steam output from the waste heat-steam conversion unit, output mechanical energy by expanding the steam, compress the ambient air into compressed air by the mechanical energy, and convert the remaining mechanical energy into electrical energy to supply power to the ship's electrical grid 16 or convert electrical energy into mechanical energy to assist in the production of compressed air.

[0053] The compressed air supply unit is connected to the steam-mechanical-electric energy conversion unit and includes a bottom release device 12 for supplying compressed air to the bottom of the ship to form an air film.

[0054] The waste steam utilization unit is connected to the steam-mechanical-electric energy conversion unit and includes a ship heat user 13 and a steam condenser 10. It is used to receive the low-pressure steam output by the steam-mechanical-electric energy conversion unit after it has done work, to provide a heat source for the ship heat user 13, and to condense the excess low-pressure steam to generate condensate.

[0055] The condensate recovery unit is connected to the steam waste heat cascade utilization unit and the waste heat-steam conversion unit. It includes a condensate collection cabinet 11, which is used to collect the condensate output from the steam waste heat cascade utilization unit and transmit it to the feedwater side of the waste gas boiler 4 in the waste heat-steam conversion unit to complete the working fluid circulation.

[0056] The intelligent integrated control unit includes a sensor network, a control unit 6, and a motor-generator integrated load control unit 17. The sensor network is used to collect ship operating parameters. The control unit 6 is electrically connected to both the sensor network and the motor-generator integrated load control unit 17. The motor-generator integrated load control unit 17 is controlled and connected to the motor-generator integrated unit 9 in the steam-mechanical energy-electric energy conversion unit.

[0057] Specifically, the exhaust gas from the main unit of this invention sequentially drives the exhaust gas turbine compressor before entering the exhaust gas boiler. The exhaust gas boiler is designed to produce saturated steam at 0.8 MPa (saturation temperature approximately 170°C), with the output varying depending on the load of the main unit.

[0058] The steam is directed to a small steam turbine, where it expands to 0.15 MPa before being discharged into the ship's existing low-pressure steam network for fuel heating, domestic water heating, etc. The shaft power output from the turbine drives a compressor via a reduction gearbox, which is also connected to a generator set. The generator set, according to the load control system, performs work on the compressor or receives work from the turbine to generate electricity.

[0059] The compressor draws in air from the engine room and compresses it to 0.5-0.7 MPa (adjustable). The compressed air enters the annular air supply manifold surrounding the bottom of the ship and finally forms a uniform air film through the microporous release plates arranged in the flat keel area.

[0060] The intelligent integrated control unit continuously collects four key signals: main engine output power (from the ECU), ship speed above ground, hydrostatic pressure at the hull (measured by a pressure sensor installed at the hull), and main gas supply pipe pressure. During operation, it adjusts the steam inlet valve opening, changes the turbine power and air compressor speed, thereby controlling the exhaust pressure to precisely track the set value. This additional pressure is sufficient to overcome pipeline resistance and ensure effective gas release.

[0061] During shutdown: The control unit gradually closes the steam inlet valve, the compressor shuts down smoothly, and all the power from the steam turbine is used to generate electricity and feed it into the power grid. Simultaneously, the low-pressure pipeline pressure is monitored; if a sudden decrease in heat user demand causes a pressure rise, the steam condenser is automatically activated to maintain stable pipeline pressure.

[0062] The entire system achieves fully automatic and adaptive operation of the air lubrication and motor power generation grid system. According to actual ship tests, under typical sailing conditions with 85% MCR main engine load, only about 40% of the flue gas waste heat is used (the remaining waste heat is used for turbine power generation and heating) to drive the air lubrication system to full load operation, achieving a net fuel saving rate of about 8%, and more than 50% of the flue gas waste heat can be used to feed power to the grid, resulting in excellent overall economic benefits.

[0063] In a specific embodiment, in the waste heat-steam conversion unit,

[0064] The input end of the exhaust gas box 2 is connected to the exhaust port of the main unit 1 and is used to receive the exhaust gas from the main unit;

[0065] The first flue gas output end of the exhaust gas box 2 is connected to the input end of the exhaust gas boiler heat exchanger 3 through the exhaust gas discharge pipeline, and the second flue gas output end is connected to the flue gas inlet of the exhaust gas turbine compressor 5 through the exhaust gas turbine release pipeline, which is used to distribute the exhaust gas of the main unit to the exhaust gas turbine compressor 5 and the exhaust gas boiler heat exchanger 3.

[0066] The output end of the waste gas boiler heat exchanger 3 is connected to the flue gas side and the feed water side of the waste gas boiler 4, and is used to heat the boiler feed water in the waste gas boiler 4 through the waste gas boiler heat exchanger 3, and convert it into hot steam with the ability to do work.

[0067] The feed water end of the waste gas boiler 4 receives boiler feed water through the waste gas boiler water supply pipeline, and the steam output end is connected to the input end of the steam-mechanical energy-electric energy conversion unit through the waste gas boiler steam supply pipeline, which is used to transport hot steam to the steam-mechanical energy-electric energy conversion unit.

[0068] The output end of the exhaust gas turbine compressor 5 is connected to the input end of the main unit 1 through the main unit scavenging pipeline, and is used to scaveng the main unit 1 with the generated compressed air and transmit the remaining exhaust gas to the exhaust gas boiler heat exchanger 3.

[0069] Specifically, the exhaust port of the main unit 1 is connected to the input end of the waste gas box 2. The first flue gas output end of the waste gas box 2 is connected to the flue gas inlet of the waste gas boiler heat exchanger 3 through the waste gas discharge pipeline L1. A first flue gas regulating valve V1 is installed on the pipeline. The second flue gas output end of the waste gas box 2 is connected to the flue gas inlet of the waste gas turbine compressor 5 through the waste gas turbine release pipeline L2. A second flue gas regulating valve V2 is installed on the pipeline to distribute the exhaust gas from the main unit to the waste gas turbine compressor 5 and the waste gas boiler 4 as needed, and to give priority to the flue gas demand of the waste gas turbine compressor 5.

[0070] The flue gas outlet of the waste gas boiler heat exchanger 3 is connected to the flue gas side of the waste gas boiler 4. The feed water side of the waste gas boiler heat exchanger 3 is connected to the feed water side of the waste gas boiler 4 through the waste gas boiler water supply pipeline L4, forming an internal circulation preheating system. The waste gas boiler water supply pipeline L4 is equipped with a waste gas boiler water supply pump P1 and a boiler water supply regulating valve V3. The feed water end of the waste gas boiler 4 receives boiler feed water pumped in by the waste gas boiler water supply pump P1 through the waste gas boiler water supply pipeline L4, and is regulated by the boiler water supply regulating valve V3.

[0071] The steam output end of the waste gas boiler 4 is connected to the input end of the steam-mechanical energy-electric energy conversion unit through the waste gas boiler steam supply pipeline L5, which is used to transport the hot steam generated in the boiler to the steam turbine 7. The pipeline is equipped with a boiler steam regulating valve V4.

[0072] The compressed air output end of the exhaust gas turbine compressor 5 is connected to the scavenging inlet of the main unit 1 through the compressed air to the main unit scavenging pipeline L3, which is used to provide boosted air to the main unit, and the remaining exhaust gas is released through the exhaust gas turbine release pipeline L2.

[0073] In a specific embodiment, in the steam-mechanical energy-electric energy conversion unit,

[0074] The steam turbine 7 is connected to the steam supply pipeline of the waste gas boiler to receive hot steam from the waste gas boiler 4 and expand it to do work, outputting mechanical energy; the output shaft is connected to the input shaft of the compressor 8 and the integrated motor generator 9 through a transmission mechanism to drive the compressor 8 to compress air and drive the integrated motor generator 9 to convert mechanical energy into electrical energy.

[0075] The air inlet of the compressor 8 is connected to the ambient atmosphere for drawing in air; its air outlet is connected to the compressed air supply unit through the air lubrication supply main pipe for outputting compressed air.

[0076] The integrated motor generator 9 is electrically connected to the ship's electrical grid 16 and is used to input electrical energy into the ship's electrical grid 16 to supply power to the ship's electrical grid load user 14 in the power generation mode, or to obtain electrical energy from the ship's generator 15 in the ship's electrical grid 16 to assist in driving the compressor 8 in the electric mode.

[0077] Specifically, this unit converts the internal energy of high-temperature and high-pressure steam into mechanical energy, and further into compressed air energy and / or electrical energy;

[0078] The steam inlet of the steam turbine 7 is connected to the steam supply pipeline L5 of the waste gas boiler. The output shaft of the steam turbine 7 is coupled to the input shaft of the compressor 8 and the integrated motor generator 9 through a gearbox or direct connection. A bypass regulating valve V8 is provided on the branch line to regulate the flow rate of the steam bypass and regulate the load of the steam turbine 7.

[0079] The air inlet of the compressor 8 is connected to the ambient atmosphere, and its outlet is connected to the compressed air supply unit through the air lubrication supply main pipe L9 for outputting compressed air. The pipeline is equipped with a lubrication air regulating valve V5.

[0080] The integrated motor-generator 9 is connected to the ship's electrical grid 16 and the integrated motor-generator load control unit 17 via circuits. When the output power of the steam turbine 7 is higher than the load of the compressor 8, the excess mechanical energy drives the integrated motor-generator 9 to feed power to the ship's electrical grid 16, providing power to the ship's electrical grid load user 14 on the ship's electrical grid 16. When the output power is insufficient, the integrated motor-generator 9 switches to electric mode and obtains power from the ship's generator 15 in the ship's electrical grid 16 to assist in driving the compressor 8.

[0081] In a specific embodiment, in the compressed air supply unit,

[0082] The output end of the air lubrication supply main is connected to the air distribution pipeline arranged along the bottom of the ship to distribute compressed air to different areas of the bottom of the ship.

[0083] The air distribution pipeline is connected to the bottom release device 12 arranged at the bottom of the ship, which is used to release compressed air to the surface of the hull to form a drag-reducing air lubrication layer.

[0084] Specifically, this unit delivers and releases the generated compressed air to the bottom of the ship to form a drag-reducing air layer;

[0085] The output end of the air lubrication supply main pipe L9 is connected to the distribution pipe L10 arranged along the bottom of the ship. The distribution pipe L10 is connected to the bottom release device 12 arranged at a specific location on the bottom of the ship (such as the flat keel area), which is used to uniformly release compressed air to the surface of the ship through micropores or other means to form a stable drag-reducing air lubrication layer.

[0086] In a specific embodiment, in the steam waste heat cascade utilization unit,

[0087] The exhaust port of the steam turbine 7 is connected to the steam inlet of the ship heat user 13 through the first branch of the low-pressure steam pipeline of the waste gas boiler, and is used to provide low-pressure steam for heating to the ship heat user 13.

[0088] The exhaust port of the steam turbine 7 is connected to the steam inlet of the steam condenser 10 through the second branch of the low-pressure steam pipeline of the waste gas boiler, which is used to condense excess low-pressure steam after the demand of the ship heat user 13 is completed, and maintain the stability of the pipeline pressure.

[0089] The condensate outlets of both the ship heat user 13 and the steam condenser 10 are connected to the condensate recovery unit.

[0090] Specifically, this unit reuses the low-pressure exhaust steam after the steam has done work, thus achieving energy recovery in stages.

[0091] The exhaust port of the steam turbine 7 is connected to the low-pressure steam network through the low-pressure steam pipeline L6 of the waste gas boiler. The pipeline is divided into two branches: the first branch is connected to the steam inlet of the ship's heat user 13, such as the fuel oil heater or the domestic water heater, through the No. 1 low-pressure steam regulating valve V6, to provide them with a heat source; the second branch is connected to the steam inlet of the steam condenser 10 through the No. 2 low-pressure steam regulating valve V7, to condense excess low-pressure steam in order to maintain the stability of the pipeline network pressure.

[0092] In a specific embodiment, in the condensate recovery unit,

[0093] The input end of the condensate collection cabinet 11 is connected to the condensate outlet of the ship heat user 13 and the steam condenser 10 respectively through the waste gas boiler steam condensate pipeline, for collecting the generated condensate;

[0094] The output end of the condensate collection cabinet 11 is connected to the waste gas boiler 4 through the condensate return pipeline, so as to send the condensate back to the waste gas boiler 4 and complete the working fluid circulation.

[0095] Specifically, this unit collects the condensate generated by the system and completes the working fluid circulation;

[0096] The condensate outlets of both the steam condenser 10 and the ship's heat user 13 are connected to the input end of the condensate collection tank 11 via the exhaust boiler steam condensate pipeline L7. The output end of the condensate collection tank 11 is connected to the feedwater side of the exhaust boiler 4 via the condensate return pipeline L8, which is equipped with a condensate return pump P2 to pump the condensate back to the exhaust boiler 4, completing the working fluid circulation of the entire system.

[0097] In a specific embodiment, the intelligent integrated control unit includes:

[0098] The sensor network includes a main engine load sensor for monitoring the main engine load, a speed sensor for monitoring the ship's speed, a hydrostatic pressure sensor for monitoring the hydrostatic pressure at the bottom of the ship, and an air supply pressure sensor for monitoring the pressure of the air lubrication supply manifold.

[0099] The control unit 6 is connected to the sensor network and electrically connected to the steam inlet regulating valve and the motor generator integrated load control unit 17 located on the steam supply pipeline of the waste gas boiler. It sends control signals to control the motor generator integrated 9 to enter the power generation mode or electric mode through the motor generator integrated load control unit 17.

[0100] Specifically, this unit achieves fully automatic and adaptive operation of the system through sensor networks and controllers;

[0101] The sensor network includes: a main engine load sensor T4 for monitoring the main engine load, a speed sensor T5 for monitoring the ship's speed, a hydrostatic pressure sensor T3 for monitoring the hydrostatic pressure at the bottom of the ship, an air supply pressure sensor T2 for monitoring the pressure of the main air supply pipe, and an air supply main flow meter T1 for monitoring the air flow rate; the control unit 6 is connected to all of the above sensor signals.

[0102] The output of the control unit 6 is connected to the boiler steam regulating valve V4, the lubricating air regulating valve V5, and the motor generator integrated load control unit 17.

[0103] Control unit 6 sends a control signal to open valve V4; makes the gas supply pressure T2 track the target value; and at the same time, controls the motor generator 9 to switch between power generation and electric mode according to the working conditions.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A marine air lubrication system based on the reuse of waste heat from main engine flue gas, characterized in that, include: Main unit (1), exhaust gas turbine compressor (5), ship electrical grid (16), waste heat-steam conversion unit, steam-mechanical energy-electric energy conversion unit, compressed air supply unit, steam waste heat cascade utilization unit, condensate recovery unit and intelligent integrated control unit; The waste heat-steam conversion unit is connected to the main unit (1) and the waste gas turbine compressor (5), and includes a waste gas box (2), a waste gas boiler heat exchanger (3) and a waste gas boiler (4); it is used to receive the waste heat of the flue gas discharged from the main unit (1) and the waste gas turbine compressor (5), heat the boiler feedwater in the waste gas boiler (4), and convert the boiler feedwater into hot steam. The steam-mechanical energy-electric energy conversion unit is connected to the waste heat-steam conversion unit and the ship's electrical grid (16), and includes a steam turbine (7), a compressor (8) and a motor-generator integrated unit (9); it is used to receive the hot steam output from the waste heat-steam conversion unit, output mechanical energy by expanding the steam, compress the ambient air by the mechanical energy to generate compressed air, convert the remaining mechanical energy into electrical energy, supply power to the ship's electrical grid (16) or convert electrical energy into mechanical energy to assist in the production of compressed air; The compressed air supply unit is connected to the steam-mechanical-electric energy conversion unit and includes a bottom release device (12) for supplying compressed air to the bottom of the ship to form an air film. The waste heat utilization unit is connected to the steam-mechanical-electric energy conversion unit and includes a ship heat user (13) and a steam condenser (10); it is used to receive the low-pressure steam output by the steam-mechanical-electric energy conversion unit after it has done work, to provide a heat source for the ship heat user (13), and to condense the excess low-pressure steam to generate condensate. The condensate recovery unit is connected to the steam waste heat cascade utilization unit and the waste heat-steam conversion unit. It includes a condensate collection cabinet (11) for collecting the condensate output from the steam waste heat cascade utilization unit and transmitting it to the feedwater side of the waste gas boiler (4) in the waste heat-steam conversion unit to complete the working fluid circulation. The intelligent integrated control unit includes a sensor network, a control unit (6), and a motor-generator integrated load control unit (17). The sensor network is used to collect ship operating parameters. The control unit (6) is electrically connected to the sensor network and the motor-generator integrated load control unit (17), respectively. The motor-generator integrated load control unit (17) is controlled and connected to the motor-generator integrated unit (9) in the steam-mechanical energy-electric energy conversion unit.

2. The marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 1, characterized in that, In the waste heat-steam conversion unit The input end of the exhaust gas box (2) is connected to the exhaust port of the host (1) for receiving the exhaust gas from the host. The first flue gas output end of the exhaust gas box (2) is connected to the input end of the exhaust gas boiler heat exchanger (3) through the exhaust gas discharge pipeline, and the second flue gas output end is connected to the flue gas inlet of the exhaust gas turbine compressor (5) through the exhaust gas turbine release pipeline, which is used to distribute the exhaust gas of the main unit to the exhaust gas turbine compressor (5) and the exhaust gas boiler heat exchanger (3). The output end of the waste gas boiler heat exchanger (3) is connected to the flue gas side and the feed water side of the waste gas boiler (4) and is used to heat the boiler feed water in the waste gas boiler (4) through the waste gas boiler heat exchanger (3) and convert it into hot steam with the ability to do work. The feed water end of the waste gas boiler (4) receives boiler feed water through the waste gas boiler water supply pipeline, and the steam output end is connected to the input end of the steam-mechanical energy-electric energy conversion unit through the waste gas boiler steam supply pipeline, which is used to transport hot steam to the steam-mechanical energy-electric energy conversion unit. The output end of the exhaust gas turbine compressor (5) is connected to the input end of the host (1) through the host scavenging pipeline, and is used to scaveng the host (1) with the generated compressed air and transmit the remaining exhaust gas to the exhaust gas boiler heat exchanger (3).

3. A marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 2, characterized in that, In the steam-mechanical energy-electric energy conversion unit The steam turbine (7) is connected to the steam supply pipeline of the waste gas boiler to receive hot steam from the waste gas boiler (4) and expand to do work, outputting mechanical energy; the output shaft is connected to the input shaft of the compressor (8) and the motor generator (9) through the transmission mechanism to drive the compressor (8) to compress air and drive the motor generator (9) to convert mechanical energy into electrical energy. The air inlet of the compressor (8) is connected to the ambient atmosphere for drawing in air; its outlet is connected to the compressed air supply unit through the air lubrication supply main pipe for outputting compressed air. The integrated motor generator (9) is electrically connected to the ship's power grid (16) and is used to input electrical energy into the ship's power grid (16) in the power generation mode to supply power to the ship's power grid load user (14), or to obtain electrical energy from the ship's generator (15) in the ship's power grid (16) in the electric mode to assist in driving the compressor (8).

4. A marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 3, characterized in that, In the compressed air supply unit The output end of the air lubrication supply main is connected to the air distribution pipeline arranged along the bottom of the ship to distribute compressed air to different areas of the bottom of the ship. The air distribution pipeline is connected to the bottom release device (12) arranged at the bottom of the ship to release compressed air to the surface of the hull and form a drag-reducing air lubrication layer.

5. A marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 3, characterized in that, In the steam waste heat cascade utilization unit The exhaust port of the steam turbine (7) is connected to the steam inlet of the ship heat user (13) through the first branch of the low-pressure steam pipeline of the waste gas boiler, and is used to provide low-pressure steam for heating to the ship heat user (13). The exhaust port of the steam turbine (7) is connected to the steam inlet of the steam condenser (10) through the second branch of the low-pressure steam pipeline of the waste gas boiler, which is used to condense excess low-pressure steam and maintain the stability of the pipeline network pressure. The condensate outlets of both the ship heat user (13) and the steam condenser (10) are connected to the condensate recovery unit.

6. A marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 1, characterized in that, In the condensate recovery unit The input end of the condensate collection cabinet (11) is connected to the condensate outlet of the ship heat user (13) and the steam condenser (10) respectively through the waste gas boiler steam condensate pipeline, for collecting the generated condensate; The output end of the condensate collection cabinet (11) is connected to the waste gas boiler (4) through the condensate return pipeline, so as to send the condensate back to the waste gas boiler (4) and complete the working fluid circulation.

7. A marine air lubrication system based on the reuse of main engine flue gas waste heat according to claim 1, characterized in that, In the intelligent integrated control unit: The sensor network includes a main engine load sensor for monitoring the main engine load, a speed sensor for monitoring the ship's speed, a hydrostatic pressure sensor for monitoring the hydrostatic pressure at the bottom of the ship, and an air supply pressure sensor for monitoring the pressure of the air lubrication supply manifold. The control unit (6) is connected to the sensor network and electrically connected to the steam inlet regulating valve and the motor generator load control unit (17) located on the steam supply pipeline of the waste gas boiler. It sends control signals to control the motor generator (9) to enter the power generation mode or electric mode through the motor generator load control unit (17).

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