Gas Turbine flows continuouslyGasDriven by working mediumimpellerhigh speedrotate, convert the energy of fuel into useful internal combustion typePower machinery, is a rotary impeller typeThermal engine。
On February 28, 2024, it was reported that the first prototype of the 300 MW Class F heavy gas turbine independently developed by China was put on the assembly line in Lingang, Shanghai.[9]
In the main processes of air and gas, onlycompressor（Compressor）、combustion chamber(Combustor) andgas turbine(Turbine)Gas turbine cycle, commonly referred to as simple loop.Most gas turbines adopt simple cycle scheme.
The compressor draws air from the outside atmospheric environment and pressurizes it step by step through the axial flow compressor, while the air temperature increases accordingly;The compressed air is pressed to the combustion chamber and mixed with the injected fuel to generate high-temperature and high-pressure gas;Then it enters the turbine to expand and do work, driving the turbine to drive the compressor and the external load rotor to rotate at high speed together, realizing that the chemical energy of gas or liquid fuel is partially converted into mechanical work, and electrical work is output.The exhaust gas discharged from the turbine is discharged to the atmosphere for natural heat release.In this way, the gas turbine converts the chemical energy of the fuel into heat energy, and also converts part of the heat energy into mechanical energy.Generally, in gas turbines, the compressor is driven by the expansion work of the gas turbine, which is the load of the turbine.In a simple cycle, about 1/2 to 2/3 of the mechanical work generated by the turbine is used to drive the compressor, and the remaining 1/3 of the mechanical work is used to drive the generator.When the gas turbine starts, it first needs external power. Generally, the starter drives the compressor. The gas turbine can only work independently until the external starter trips when the mechanical work generated by the gas turbine is greater than the mechanical work consumed by the compressor.
Development overview
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In 1791, British Barber first describedGasWorking process of turbine;In 1872, German Stolze designed a gas turbine and conducted tests from 1900 to 1904StarterFailure due to independent operation;In 1905, Le Maire and Armango, the French, made the first gas turbine capable of outputting work, but its efficiency was too low to be practical.
In 1920, German HoltzwattThe first practical gas turbine with efficiency of 13% and power of 370KilowattIt works according to the constant volume heating cycle, but it is abandoned because of many major shortcomings of the constant volume heating cycle, which is heated by intermittent deflagration.
With the development of aerodynamics, people have mastered the characteristics of gas diffusion flow in compressor blades, and solved the problem of high design efficiencyAxial compressorAs a result, an axial flow compressor with an efficiency of 85% appeared in the mid-1930s.At the same time, the turbine efficiency has also been improved.stayHigh-temperature materialOn the other hand, heat-resistant steels such as chromium nickel alloy steel that can withstand high temperatures above 600 ℃ have emerged, so that higher initial gas temperature can be used, and the gas turbine with constant pressure heating cycle has finally been successfully applied.
In 1939SwitzerlandA four megawatt gas turbine for power generation has been made, with an efficiency of 18%.In the same year, the test flight of the jet aircraft manufactured in Germany was successful, and the gas turbine entered the practical stage and began to develop rapidly.
With the continuous development of high-temperature materials and the adoption of turbineCooling bladeThe cooling effect is continuously improved, and the initial temperature of gas is gradually increased, so that the efficiency of gas turbine is continuously improved.The power of a single machine is also increasing. In the mid-1970s, several types of 100 MW gas turbines appeared, with a maximum capacity of 130 MW.
At the same time, the application field of gas turbine is expanding.1941Made in SwitzerlandThe first gas turbine locomotive of has passed the test;In 1947, the first gas turbine equippednaval vesselsWhen launched, it uses 1.86 MW gas turbine as afterburner power;In 1950, Britain made the first gas turbine car.Since then, gas turbines have been used in more departments.
While gas turbines are widely used, gas turbines and otherheat engineCombined composite device.It first appeared with the piston typeinternal-combustion engineCombined device;In the 1950s and 1960s, the free piston gas generator and gas turbineFree piston gas turbine unitHowever, due to its bulkiness and complex system, production stopped in the 1970s.In addition, diesel and gas turbine composite devices have also been developed;Another type of full energy system using gas turbine exhaust heat for heating (or steam) can effectively save energy and has been used in various industrial production.At present, LM2500 and GT25000 are the most classic engines with the most applications.
In February 2023, the first domestic heavy-duty gas turbine with the highest energy efficiency level of air cooling was successfully rolled out in Qinhuangdao, Hebei Province, which is a new breakthrough in the production and manufacturing technology of domestic heavy-duty gas turbines.[8]
market share
There are 28 famous enterprises engaged in gas turbine research, design, production and sales all over the world, and there are about 50000 industrial gas turbines used all over the world, and the global gas turbine market is almost monopolized by European and American companies.
Due to different historical backgrounds and different technical development paths of gas turbines, industrial and marine aero-engine aero-engine light gas turbines (commonly known as "aero-engine aero-engine") are formed by aero-engine retrofitting;Industry developed following the traditional steam turbine conceptHeavy duty gas turbine(commonly known as "industrial machine"), mainly used for mechanical drive and large power stations.
Industrial overview
Before liberation, there was no gas turbine industry in China. After liberation, dozens of types of gas turbines for land, sea and air use have been trial produced all over the country.In 1956, the first batch of jet aircraft manufactured in China flew. Since 1958, many factories have designed and manufactured various gas turbines.
1962Shanghai Steam Turbine WorksTrial productionMarine gas turbineIn 1964, we cooperated with Shanghai Shipyard to produce 550KW gas turbine, in 1965, we produced 6000KW gas turbine for train power station, and in 1971, we produced 3000KW truck power station.During this period703 Research InstituteSeveral marine gas turbines, such as 3295KW, 4410KW and 18380KW, have been jointly manufactured.
In 1969, Harbin Steam Turbine Factory produced 2200KW locomotive gas turbine and 1000KW free piston gas turbine. In 1973, it cooperated with 703 Research Institute to produce 4410KW marine gas turbine and Changchun Locomotive and Rolling Stock Factory to produce 3295KW locomotive gas turbine.
In 1964, Nanjing Steam Turbine and Electric Machinery Factory made 1500KW gas turbine for power station;Made 37KW gas turbine for pump in 1970;Made 1000KW power station gas turbine in 1972;In 1977, it was made into a 21700KW fast installed power station gas turbine;In 1984, it cooperated with GE to produce PG6541B 36000KW gas turbine;From 1984 to 2004, four types of gas turbines PG6541B, PG6551B, PG6561B and PG6581B have been produced, and the power has increased from 36000KW to 43660KW.In 2003, the National Development and Reform Commission decided to further expand the scope of cooperative production between Nanjing Steam Turbine Motor Group Co., Ltd. and GE, and to produce gas turbines, steam turbines and generators in the S209E gas steam combined cycle power plant in Nanjing Steam Turbine Motor Group Co., Ltd.
1978Dongfang Turbine Works6000KW gas turbine;In 1972, Hangzhou Steam Turbine Factory made 200KW gas turbine;In 1972, Qingdao Steam Turbine Factory made 1500KW truck power station gas turbine.
In 2003, the National Development and Reform Commission decided to build a gas turbine production base in Qinhuangdao and cooperate with GE to produce MS9001FA gas turbines.The production base is affiliated to Harbin Electric Power Group, and is jointly operated with Harbin Turbine WorksHarbin Electric Machinery FactoryJoint production of S109FA-SS gas steam combined cycle power generation equipment.The first MS9001FA gas turbine assembled in Qinhuangdao in August 2004 has been shipped to Hangzhou Banshan Power Plant.
On December 15, 2004, China's first heavy gas turbine with independent intellectual property rights, AVIC LimingR0110 Heavy Duty Gas TurbineComplete the 72 hour on load test operation assessment at the site of CNOOC Shenzhen Electric Power Co., Ltd.This operation assessment verified the design status of R0110 heavy gas turbine, which is an important milestone in the development process of heavy gas turbine and lays a good foundation for future commercial operation.
On November 25, 2022, after 13 years of independent research and development, the first domestic F-class 50 MW heavy gas turbine known as the "gas engine" was successfully rolled off the production line in Dongfang Turbine Co., Ltd. of Dongfang Electric Group, and delivered from Deyang, Sichuan.[7]
working principle
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schematic diagram
The working process of gas turbine is that the compressor (i.e. compressor) continuously draws air from the atmosphere and compresses it;The compressed air enters the combustion chamber, mixes with the injected fuel and burns to become high temperature gas, then flows into the gas turbine to expand and do work, driving the turbine wheel to rotate with the compressor wheel;The work capacity of the heated high temperature gas is significantly improved, so the gas turbine has residual work as the output mechanical work of the gas turbine while driving the compressor.When the gas turbine starts from a standstill, it needs to rotate with the starter. The starter will not be disconnected until it is accelerated to independent operation.
The working process of gas turbine is the simplest, called simple cycle;In addition, there are regenerative cycles and complex cycles.The working medium of gas turbine comes from the atmosphere and is finally discharged to the atmosphere, which is an open cycle;In addition, there is a closed cycle in which the working medium is used in a closed cycle.The combination of gas turbine and other heat engines is called compound cycle device.[1]
The initial temperature of gas and the compression ratio of compressor are two main factors affecting the efficiency of gas turbine.The efficiency of gas turbine can be significantly improved by increasing the initial temperature of gas and correspondingly increasing the compression ratio.At the end of 1970s, the compression ratio reached 31;The initial gas temperature of industrial and marine gas turbines is up to about 1200 ℃, and that of aviation gas turbines is over 1350 ℃.
Advantages and disadvantages
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Gas turbines are seldom used in general automobiles and personal machinery, which is related to their advantages and disadvantages.In fact, some automobile companies have developed gas turbine family cars. For example, in 1950, JET 1.0 made by Rover or Chrysler Turbine Car made by Chrysler worked hard for decades until the 1980s, but finally gave up the plan because the disadvantages outweighed the advantages.[2]Finally, military vehicles, aircraft and ships are more suitable for use after the 21st centuryJaguarThe C-X75 concept car was launched to try to drive the gas turbine after charging the battery as a power generation deviceElectric vehicle, became a new concept attempt, but still did not solve the price and emission standards.
Advantages
The situation of directly outputting rotary motion and not converting linear reciprocating motion into rotary motion is suitable for gas turbines, so jet engines and ships are very suitable, but generators or cars used by ordinary people are not the best.
There is no need to warm up the engine and there are not so many cold start problems. In cold weather areas, there is no need to add antifreeze.
Support a variety of fuels: gasoline, diesel, kerosene, peanut oil, almost any flammable liquid or even mixed liquid.[3]
Disadvantages
It is suitable for high-speed and stable operation. The efficiency is much lower when idling or accelerating, and the fuel consumption is very high when idling.This can be regarded as the most unsuitable reason for household cars.
During operation, the temperature in the engine is continuously high, and the high requirements for high temperature resistance and durability of materials result in high prices.
The noise is loud, even if there is a unique sharp noiseDecibelLowering is still unbearable for many people.
The instantaneous response is not good, which has an impact on the use of vehicles in urban environments.
NOxnitrogen oxide The emission of is exponentially related to the temperature, so the turbine with high temperature has extremely high emissions, which can be regarded as the most fatal disadvantage under the situation of stricter emission standards.
internal structure
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The combustion chamber and turbine not only work at high temperature, but also bear the thermal shock caused by the drastic change of temperature when the gas turbine starts and shuts down. The working conditions are bad, so they are the key components that determine the life of the gas turbine.In order to ensure adequate service life, the parts with the worst working conditions, such as flame tube and blade, must be made of nickel base andCobalt base alloyAt the same time, air cooling must be used to reduce the working temperature.
For a gas turbine, in addition to its main components, it must also be equipped with a complete regulation and security system, as well as good auxiliary systems and equipment, including starting device, fuel system, lubrication systemAir filter, intake and exhaust silencers, etc.
There are two types of gas turbines: heavy and light.Heavy parts are relatively heavy, with a long overhaul cycle and a service life of more than 100000 hours.The light structure is compact and light, and the materials used are generally good. Among them, the structure of the aircraft is the most compact and light, but its service life is short.
With piston internal combustion engines andSteam power plantIn comparison, the main advantage of gas turbine is small and light.The mass per unit power of heavy gas turbine is generally 2-5kg/kW, while that of aircraft is generally lower than 0.2kg/kW.The gas turbine occupies a small area. When it is used for transport machinery such as vehicles and ships, it can not only save space, but also equip a more powerful gas turbine to improve the speed of vehicles and ships.The main disadvantage of gas turbine is that the efficiency is not high enough, the efficiency drops quickly under partial load, and the fuel consumption is high under no-load.
Different application departments have different requirements and service conditions for gas turbines.Most of the gas turbines with power above 10 MW are used for power generation, while almost all of those with power above 30~40 MW are used for power generation.
Gas turbine generator setIt can be quickly started without external power supply, and has good mobility. It can be used to drive peak load and serve as emergency standby in the power grid, and can better ensure the safe operation of the power grid, so it is widely used.In automobile (or trailer) power station and train power station, etcMobile power stationThe gas turbine is widely used because of its light and small size.In addition, there are many portable power supplies using gas turbines, with the minimum power below 10 kilowatts.
The future development trend of gas turbine is to improve efficiency, use high-temperature ceramic materials, use nuclear energy and develop coal-fired technology.The key to improve efficiency is to increase the initial temperature of gas, that is, to improve the cooling technology of turbine blades and develop high-temperature materials that can withstand higher temperatures.The second is to improve the compression ratio and develop compressors with fewer stages and higher compression ratio.Thirdly, improve the efficiency of each component.
High temperature ceramic materials can work at a high temperature above 1360 ℃. When they are used as high-temperature parts such as turbine blades and flame tubes of combustion chambers, the initial temperature of gas can be greatly increased without air cooling, thus greatly improving the efficiency of gas turbines.High temperature ceramic materials suitable for gas turbine include silicon nitride and silicon carbide.
The device working in closed cycle can use nuclear energyHigh temperature gas cooled reactorAsheaterThe coolant (helium or nitrogen, etc.) of the reactor serves as the working medium of the compressor and turbine at the same time.
lubrication system
gas turbinelubricationOil system is an essential part of any gas turbineAuxiliary system。Its function is to provide information to all operating gas turbine generator units during unit startup, normal operation and shutdownBearing, transmission device and accessoriesequipment, supply sufficient quantity, temperature andpressureSuitable and clean lubricating oil to ensure the unitsecurityReliable operation to prevent bearing burningrotorOverheating and bending of journal, high speedgearFlange deformation and other accidents.In addition, some lubricating oil may be separated from the system and becomeHydraulic oilOil source of the system, or filtered ascontrolOil for oil system.
The lubricating oil system of the combined cycle power generation unit has several different configurations. For single shaft units, the gas turbine and steam turbine share a set of lubricating oil system;For multi shaft units, gas turbine generator units and steam turbine generator units can share a set of lubricating oil system, or they can have a separate set of lubricating oil system, which depends on the overall layout of the unit. However, due to the needs of phased construction of the power station, most multi shaft units adopt a separate set of lubricating oil system;There is also an aviation derived gas turbine. Due to the high initial gas temperatureGas generatorIt is required to use higher quality lubricating oil, so the gas generator is equipped with a separate set of lubricating oil systemPower turbineAnother set is set with the generator, the former uses synthetic oil, and the latter uses mineral oil.
As far as the lubricating oil system is concerned, whether it is a shared system or a separate systemDesignThe principle is the same.The whole lubricating oil system shall include the following equipment:
Lubricating oil tank
The lubricating oil tank can be located in one or several chassis of the unit, or can be designed as a separate container.When the oil tank is composed of several containers, pipes shall be connected between them tobalancePressure in the tank.In addition to the function of oil storage, the oil tank also undertakes the task of separating air, water and various mechanical impurities.The oil flow speed in the oil tank shall be as slow as possible, and the oil return pipe shall be arranged at the oil level close to the oil tank to facilitate the escape of air in the oil layer.The larger the capacity of the oil tank, the more conducive to the separation of air, water and various impurities.The system is usually represented by the circulation ratio K (the number of times that all lubricating oil passes through the oil tank per hour)volumeQ is the volume flow of oil per hour of the system, V is the volume of the system (oil tank+pipeline), and the circulation ratio K=Q/V.It is generally specified that K=8~10, and the maximum value shall not exceed 12.This is to make the lubricating oil returned from the system have enough time to separate the air and water carried by it.However, in order to have a compact structure and avoid bulky equipment due to the large volume of oil tank, the oil tank capacity of most units is too small, which forces users to choose better water separation performance andAir release valueSmaller lubricating oil.
Main lubricating oil pump
This is the working oil pump during normal operation of the unit, which can be driven by the main engine through auxiliary gear, or byalternating currentDriven by a motor, large units often adopt electric drive in order to simplify the structure.The capacity of the oil pump is based on the total oil consumption of the systemRegulating valveOverflow and pipeline leakage are determined.Common main oil pumps areGear pumpAnd screw pump, or centrifugal pump.
Auxiliary oil pump
This is the working oil pump when the unit is started and stopped, or put into use when the main oil pump failsAC motorDrive.This pump is mostly immersed centrifugal pump.Its pressure and capacity are generally the same as or slightly higher than that of the main oil pump.
Emergency oil pump
The pump is stopped due to auxiliaryLubricating oil pumpIt is put into operation due to failure, or because of loss of AC power supply, or because the main pump and auxiliary pump can not work and the unit can not be shut down in an emergency.As the emergency pump only works in case of failure, its pressure and capacity are generally small.Some lubricating oil systems use high-level oil tank instead of emergency oil pump.
The temperature of lubricating oil rises by 14~33 ℃ after passing through each lubricating point (bearing, gear, etc.) (when equipped with reduction geartemperature riseUp to 33 ℃), so the lubricating oil returned from the system must be cooled to ensure proper oil supply temperature.Tubular oil cooler is still widely used.frequently-usedCooling modeIt is water cooling, followed by air cooling. The advantage of air cooling is that it does not need cooling water and can be used in water scarce areas. However, because the heat transfer coefficient of air is much lower than that of water, the volume of air cooled oil cooler is relatively large.When water cooling is adopted, two parallel switchable oil coolers are often set.
The main lubricating oil filter mostly adopts two switchable filters in parallelOil filter。The main oil filter shall be set at the downstream of the oil cooler.
In addition to the above equipment, the lubricating oil system also needs valves, orificesTemperature switch、Pressure switch, Oil tanklevelIndicatorLube oil heaterAnd other components and facilities to ensure the normal, safe and reliable operation of the system.
To ensure the safety of gas turbine and its drivingequipmentProvide goodlubrication, except that there areDesignperfectLubricating oilIn addition to the system, the selection of lubricating oil with superior performance is also an important factor.Early gas turbineTurbine inlet temperatureNot very high. The lubricating oil used is basically the same as the turbine oil. However, with the continuous improvement of the turbine inlet temperature, the emphasis of the gas turbine on the lubricating oil quality index is obviously different from that of the turbine. The gas turbine emphasizes the high temperature resistance of the oilOxidizabilityYes, but the turbine depends on the resistance of heavy oilemulsificationPerformance (water separation performance).Many manufacturers are developing the above two kinds of combined cycle oil with excellent performance, especially the oil for single shaft units with the same lubricating oil system.The lubricating oil isBase oilAdd rust prevention, corrosion prevention, oxidation resistance, etcadditiveFinished products after.The base oil can be either mineral oil or synthetic oil.Due to the high purity of synthetic oil, its performance and service life are better than mineral oil, butPriceIt is generally 2-3 times of mineral oil.The performance indicators for evaluating the advantages and disadvantages of lubricating oil include physical properties, surface properties and oxidation properties of oil. For this, gas turbine manufacturers will put forward selection suggestions.
In principle, the requirements for lubricating oil are as follows:
1. Requirements adaptationBearing、gearStartup, acceleration, full speed and overspeed of devicesworking conditionRequired lubricating oil properties.
2. Requirements adaptationHydraulic systemSuch as oil cylinderServo valveAnd other required hydraulic oil performance.
3．heat transferOil performance.It can absorb the heat of various hot surfaces such as bearings and gear units and transfer it to the lubricating oil heat exchanger (oil cooler).
4. It has stable physical properties, surface properties and oxidation properties under certain temperature and pressure, static or storage conditions.
5. It can adapt to various mechanical materials in the lubrication system and other oil systems, and can protect the materials from corrosion.
6. Automatic exclusionAir and waterAnd other pollutants.
7. It has certain flame resistance.
When selecting lubricating oil, in addition to following the recommendations of the equipment manufacturer, the following performance indicators should be emphasized:
1. Viscosity and viscosity index
For normal temperatureGas turbine startEnsure the hydrostatic lubrication of each bearing and the quick response capability of the hydraulic system. It is hoped that the viscosity of lubricating oil will not be too high when starting. For this reason, most of theTurbomachinerySelect lubricating oil with viscosity of 28.8~35.2/s at 40 ℃, that is, lubricating oil with viscosity grade of ISOVG32.When the gas turbine operates normally with load, the working temperature in the bearing clearance may be higher than 120 ℃. At this time, the oil viscosity is required to be higher.For this reason, the lubricating oil with a relatively gentle viscosity change with temperature, that is, a large viscosity index, should be selected.It is recommended that the viscosity index of the oil should be above 100 and at least not less than 90.
2. Oxidation stability
When the gas turbine works, the lubricating oil is subject to strong thermal oxidation,Turbine oilVolatile rust prevention commonly usedantioxidantThe lubricating oil for gas turbine is not suitable.For bearings operating at temperatures higher than 260 ℃, literature 49 clearly stipulates that DBPC should not be contained in the lubricating oil used（Di-tert-butyl-p-cresol）A class of volatile antioxidants.For oxidation stability, the traditional assessment index is the number of hours required when the acid value of the oil reaches 2.0mgKOH/g after oxidation (commonly referred to as TOSTLife abroad, that is, total oxidationstability test Service life), when the initial temperature of gas is not very high, it is enough to only check this indicator, and only requires it to be more than 2000h.
However, since TOST is conducted under the test condition of 95 ℃, which is quite far from the working temperature of gas turbine bearings, it is not enough to assess TOST for the new generation of gas turbines with higher initial temperature, so the rotating oxygen bomb test index of oil is added to assess the performance of oil at higher temperature.The temperature of rotating oxygen bomb test is 150 ℃, much higher than TOST.
3. Demulsification value, also known as water separation performance
This refers to the separation ability of oil and water. The measurement method is to put 40mL oil and 40mL water into a special test tube, mix them according to the specified test procedure, and then measure the time (min) for complete or basically complete separation of oil and water. The degree of oil and water separation can be 40-37-3.40-40-0, etc.For gas turbines, this is not a very important performance index, because it is unlikely that the lubricating oil will be polluted by water (or steam) in gas turbines.However, in the steam turbine, the possibility of oil water mixing is very high, and the demulsification value of oil cannot be ignored. Its index is at least that the oil water separation is 40-37-3, and the time is not more than 15min.For combined cycle power plant, if gas turbine and steam turbine share lubricating oil system, high temperature performance and water separation performance of oil must be considered.
4. Air release value
Since most gas turbine bearings use seal air, air will inevitably be mixed in the return oil of bearings.The air entering the oil layer must be released from the oil layer within a short stay time after the oil returns to the oil tank.When selecting lubricating oil, its air release value should not be greater than the time when the oil circulates once in the oil tank.
5. Foaming performance
Foaming performance and air release value are two interrelated and easily confused concepts.In fact, air release occurs within the oil layer, and foam is generated above the oil surface.It is generally believed that it is normal to form a 5mm foam on the oil surface.However, if there is too much foam and the air vent of the oil tank is full of foam, serious consequences will be caused due to the obstruction of air discharge.Therefore, the foaming performance of the oil shall at least meet the standard of general turbine oil.
In addition, the color of new oil should be light, and should not exceed 2.0 in ASTM D1500.For units with load gearbox, the bearing capacity of oil must be considered, and oil with bearing capacity (FZG) above grade 7 shall be selected.
power plant
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With high-temperature gas as working medium, the chemical energy in the working fuel of heating cycle under constant pressure is converted intomechanical energyandelectric energyFactory.Gas turbine power plant fluids andgaseous fuelThe gas turbine is converted into mechanical energy, which then drives the generator to generate electricity.[4]
Gas turbineAdiabatic compression, isobaric heatingAdiabatic expansionAnd equal pressure heat release are respectively completed in the compressor chamber, combustion chamber, gas turbine and regenerator or atmosphere.The compressor of large gas turbine is multi-stage axial flow type, and the medium and small ones are centrifugal type.The gas turbine is generally axial flow type, which is used for centripetal type in small units.Gas turbine drives gas compressor and generator.The single unit capacity of gas turbine units is about 10~20kW for small ones and 140MW for the largest ones.The thermal efficiency is 30%~34%, up to 38%.There are two types of gas turbine structures: heavy and light, and the latter is mainly modified by aeroengines.
Because of its small size, light weight, fast start, fast installation, little or no water, it can use a variety of liquid and gaseous fuels, and is mostly used for peak shaving in power generation.In addition, gas turbines are also widely used in oil and gas exploitation and transportation, transportation, metallurgy, chemicals, ships and other fields.
seal up
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The advanced sealing technology of gas turbine is a branch field that has attracted great attention abroad in recent decadesseal upThe benefits brought by technology have been realengine performance Improve, reduce fuel consumption, and reduce operation and maintenance costs.
Cylinder seal:
staySteam turbineDuring operation, steam turbine leakage and cylinder deformation are the most common equipment problems. The tightness of the cylinder junction surface directly affects the safe and economic operation of the unit. Overhauling and scraping the cylinder junction surface to make it tight is an important work for cylinder maintenance. In the process of dealing with steam leakage at the junction surface, carefully analyze the causes, and according to the degree of deformation and the size of the gap,Various methods can be used comprehensively to meet the requirement of tight joint surface.
Cylinder sealing is metal to metal sealing contact. Absolute sealing can be formed only when the sealing contact pressure causes permanent deformation of the contact surface.However, this is not allowed, and the cylinder surface deformation will affect the next sealing effect.Therefore,Bolt preloadThe limit of must ensure that the cylinder surface deformation is within the elastic range.However, the bolt force that causes elastic deformation of the cylinder surface is not enough to form a high temperature and high pressure resistant gas tight seal, even when the cylinder surface is extremely highSurface finishUnder the condition of perfect cylinder surface, leakage will still occur.Because, although the surface is very good, there are always very small surface defects that can generate enough leakage channels through the air flow.
Marine machine
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Ship power plant mainly includes steam power plantDiesel power unit、Nuclear power plant, gas power plant andCombined power unit。The first two devices developed earlier and are widely used in all kinds of ships. The last three are new power devices that have developed rapidly in the past decade.warshipGas turbine power unitIt refers to the fully combusted power plant with gas turbine as the main engine.It has been widely used since the late 1950s, especially since the mid-1960s.The total power is growing day by day, and the scope of use of ship installation is expanding day by day, which has developed from speedboats to frigatesMissile equipped destroyer, cruisers and helicopter aircraft carriers.
Power advantage
In the selection of warship power scheme, the main competitors of gas turbines are marine diesel engines and marine steam turbines. However, because the inherent advantages of gas turbines are more consistent with the performance requirements of warship power systems, gas turbines have become the only choice for the development of warship power systems in various countries.Old naval powers such as the United States Navy, the British NavyJapan Maritime Self Defense ForceThe main surface warships have only completed the power and gas turbine.
The first advantage of gas turbine ispower density extremely.Generally, the volume of gas turbine with the same power is one-third to one-fifth of that of diesel engine and one-fifth to one tenth of that of steam turbine.This is due to the ingenious continuity of the gas turbine itselfturnDue to the thermodynamic cycle structure, it is small in size and large in power, which is very suitable for the characteristics of small subdivision and high speed requirements of warships.
The second advantage of gas turbine is its fast starting speed.Although the rotating speed of the gas turbine is the highest among the three power systems, because the whole rotor is very light, it can reach the highest speed in 1-2 minutes with the help of the starter.As the rotor motion of the diesel engine is due to the reciprocating of the piston, the acceleration is slow, and the steam turbine is more "unresponsive", the whole system reachesMaximum powerThe output may take up to an hour.The starting speed has a direct impact on the acceleration and deceleration performance of warships during wartime deployment and anti submarine warfare.
The third advantage of gas turbine isNoiseLow frequency components are very low.As the gas turbine itself is in the process of high-speed and stable rotation, the noise generated is more high-frequency whistling.The reciprocating piston of the diesel engine produces a lot of low frequenciesmechanical vibrationNoise just caters to the characteristics of low-frequency noise easily spread in the ocean, which makes warships easy to be detected by enemy sonar.Therefore, diesel power is particularly unsuitable for the power system of anti submarine warships.
inferiority
As gas turbines need to inhale a large amount of fresh air while working, and emit a large amount of exhaust gas, the use of gas turbines in military ships will lead to the smoke exhaust system occupying a large number of ship space. In short, it requires a larger chimney than the steam turbine, thus leading to the limitations of other equipment in space and structure.
Not equipped
The development of marine gas turbine in China is not too late.According to the introduction of the "Interview Record of Chief Marine Gas Turbine Engineer of China", in 1958, China began to organize and implement the research and development plan, and decided to establish two joint design teams in the north and south to carry out the feasibility demonstration and scheme design of large, medium and small type units first.At the end of 1959,Former Soviet UnionTransferred M-1 ship use to ChinaGas Turbine Technology China has imitated the unit for the purpose of technical training.It only took 11 months for Shanghai Turbine Works to complete the first prototype of this type of gas turbine.However, due to various reasons, the imitated prototype passed the acceptance test after 3 years of troubleshooting.Later, this type of gas turbine was tested on a high-speed gunboat and equipped with troops.The 6000 hp gas turbine unit designed in 1964 was the first marine gas turbine designed and developed by China itself, but it was unable to equip the army due to the long development cycle and the adjustment of the original assembly object plan.Unlike other countries in the world, which mainly rely on the conversion of aero engines to gas turbines, China has adopted the road of simultaneous improvement and special development because of the backward level of aero engines.
In 1967, China decided to improve the turbojet 8 engine on the Bomber VI bomber to a high-power shipboard gas turbine, which was the first time for China to carry out the practice of "aviation to combustion", but it ended up with no result because developed countries agreed to import corresponding models.Later, our country has been trying in the field of marine gas turbine, but has not been able to produce a mature and reliable carrier gas turbine with excellent performance.This is why China's six destroyers equipped with gas turbines all use foreign products, of which 112.113 destroyers are equipped withLM2500 gas turbineIt is also difficult to obtain overhaul after reaching the service time limit.
Development of aviation power industry drag down marine gas turbine
There are many main reasons why China has not been able to break through the technical bottleneck in the field of shipborne gas turbines, including both the problems of aviation power and the system problems of the marine gas turbine industry itself.One of the main reasons is that China's aviation power industry lacks long-term development planning.Like many backward countries, China's aviation power industry started from imitation and repair.With the help of Big Brother, China has quickly established an aviation industry system that can match the world-class level. However, China has not formulated a long-term development plan for the aviation industry and the aviation power industry from imitation to development, but has limited the tasks of the aviation industry itself to imitation, production and repair, and has determined "batch plants everywhere" focusing on productionDevelopment policy.The running state of China's aviation industry is imitation production and reproduction. In this state of development for a long time, China's aviation power industry has extremely insufficient understanding of the objective laws of the research and development of modern aviation power systems.
The development of aeroengine failed to break through the relevant technical bottlenecks, and there is no way to talk about the marine gas turbine which is similar to aeroengine technology.In 2004, QC185, a new domestic gas turbine developed by AVIC I, was first launched at Zhuhai Air Show.This is a light gas turbine based on Taihang core engine, butoutput powerThe level of 17 MW is also insufficient for the development of large surface ships in China.In addition, the main development and production units of marine gas turbines in China exist outside the aviation industry, which is very detrimental to the improvement project from aeroengines to gas turbines in terms of system.
Power generation form
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Simple power generation
The cycle system composed of gas turbine and generator is also called open cycle.Its advantages are fast installation, flexible start and stop, and it is mostly used for peak shaving of power grid, traffic and industrial power systems.At present, the most efficient open cycle system is GE LM6000PC light gas turbine, with an efficiency of 43%.
electricity generation
Gas turbine, generator andWaste heat boilerIt is a common circulating system, which recovers the high-temperature exhaust gas discharged from the gas turbine after work through the waste heat boiler and converts it into steam or hot water for use.It is mainly used for cogeneration. It also injects steam from waste heat boiler back into gas turbine to improve output and efficiency of gas turbine.The front reinjection cycle system with the highest efficiency is GE LM5000-STIG120 light gas turbine, with the efficiency of 43.3%.The total efficiency of pre cycle cogeneration generally exceeds 80%.In order to improve the flexibility of heating, most of the front cycleCogeneration unitThe waste heat boiler supplementary combustion technology is adopted, and the total efficiency during supplementary combustion exceeds 90%.
Cogeneration
Gas turbine and generator are combined with waste heat boiler, steam turbine or heating steam turbine (extraction type or back pressure type) to form a circulating system, which converts the high temperature exhaust gas discharged from the gas turbine into steam through waste heat boiler recovery, and then injects steam into the steam turbine for power generation, or uses part of the exhaust steam after power generation for heat supply.The forms are gas turbine and steam turbine coaxial driving a single shaft combined cycle of a generator, and gas turbine and steam turbine respectively driving their own multi shaft combined cycle of generators.It is mainly used for power generation and cogeneration. The combined cycle system with the highest efficiency during power generation is ABB GT26-1, with an efficiency of 58.5%.
Integration cycle
fromGas producer, gas turbine, waste heat boiler and steam turbine, also known as IGCC.It mainly solves the problem of using cheap solid fossil fuels instead of gas turbines to use gas and liquid fuels, improving coal utilization efficiency and reducing pollutant emissions.It can be used as a comprehensive supply system for urban gas, electricity, central heating and cooling, building materials and chemical raw materials.The power generation efficiency of the whole cycle system composed of MS7001F technology by GE can reach 42%.
combined cycle
The power generation cycle system consists of gas turbine, waste heat boiler, nuclear reactor and steam turbine.The flue gas discharged from the gas turbine reheats the steam output from the nuclear reactor, mainly to increase the temperature and pressure of the steam in the nuclear reactor, improve the efficiency of the steam turbine, and reduce the engineering cost of the steam turbine.At present, it is in the trial stage.
Auxiliary cycle
In the post circulating power generation steam turbine unit using coal, oil, etc. as fuel, small gas turbine is used as the auxiliary circulation system of the power plant to preheat and blast the boiler, improve combustion, improve efficiency, and directly use power to drive the feed pump.In 1947, the first industrial gas turbine in the United States used this method to participate in the operation of the power generation cycle system.
Gas flue gas
By gas turbine andFlue gas turbineThe circulating system is composed of, which makes use of the residual pressure and enthalpy in the flue gas emitted by the gas turbine to further promote the power generation of the gas turbine.Compared with the gas steam combined cycle system, this system can completely use no water, but the cost of flue gas turbine is high and it has not been widely used.[5]
Gas heat pump
The energy utilization system consists of gas turbine and flue gas heat pump, gas turbine, flue gas turbine and flue gas heat pump, or gas turbine, waste heat boiler, steam heat pump, as well as gas turbine, waste heat boiler, steam turbine and steam (flue gas) heat pump.After the gas turbine, flue gas turbine, waste heat boiler, steam turbine and other equipment complete the energy utilization cycle, the system further uses the heat pump to deeply recycle the waste heat of flue gas, steam, hot water and cooling water, or directly drives the power to the heat pump.This process can be used for cogenerationCogeneration of heat, power and coolingThe thermal efficiency of this system is extremely high. If it is used for direct heating, the thermal efficiency can reach 150%, which is one of the main trends of energy utilization in the future.
Hybrid fuel cell
The US Department of Energy announced the development of the world's firstgas turbines Combined with power generation equipment, such equipment can produce electricity more effectively and greatly reduce environmental pollution.It is understood that the fuel cell of this device consists of 1152 ceramic tubes, each of which serves as a battery.The battery uses natural gas as fuel, which can emit high temperature and high pressure exhaust gas flow. The gas turbine uses the hot exhaust gas flow generated by the fuel cell to generate the second round of electricity.Since there is no combustion process in the fuel cell, electricity is generated only by chemical decomposition of natural gas fuel, which can greatly reduce pollution.The device will not generatesulfur dioxide, in the reaction productnitrogen oxide The content is less than 2% of natural gas power generation equipment,carbon dioxideEmissions were reduced by 15 per cent.Moreover, as long as there is natural gas and air, fuel cells can work.The power generated by the new generation equipment is 220 kW, which can provide power for 200 households.Its power generation efficiency reaches 55%, which means that 55% of the energy from natural gas fuel has been converted into electric energy, which is far higher than 35% of the power generation efficiency of coal-fired power generation equipment and 50% of the power generation efficiency of gas turbines.
Domestic status
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Gas turbine is an advanced and complex complete set of power machinery equipment, which is a typical high-tech intensive product.As the carrier of high-tech, gas turbine represents the comprehensive level of development of multi theoretical disciplines and multi engineering fields, and is the leading technology in the 21st century.The development of gas turbine industry integrating new technology, new materials and new processes is one of the important symbols of the national high-tech level and scientific and technological strength, and has a very prominent strategic position.[6]
Due to various reasons, there is still a big gap between China's gas turbine industry and the international advanced level, and a real industry has not yet formed.The backward power in many fields has become the "bottleneck" that restricts the development of the national economy. Its technology is only controlled by a few developed countries in the world. Advanced gas turbines in Western countries still restrict exports to China.
Gas turbine is a major core equipment. If we rely on imports for a long time, we will be restricted in key technologies, which is not conducive to the healthy and rapid development of China's gas turbine power industry and related industries.From the perspective of market capacity, three of China's four major projects in the new century, namely, the "West East Gas Transmission Project", the "West East Power Transmission Project" and the "South to North Water Transfer Project", require a large number of 30 MW industrial gas turbines. Meanwhile, the healthy and rapid development of China's shipbuilding industry requires a large number of 30 MW marine gas turbines. China has become the world's largest potential gas turbine market.
In the face of the new situation of economic globalization, fierce competition in the international gas turbine market and high foreign monopoly, the state attaches great importance to the development of China's national gas turbine industry. The National Development and Reform Commission and the Ministry of Science and Technology have incorporated the ideas and countermeasures of China's gas turbine market development into the "12th Five Year Plan" and long-term development plan,Heavy gas turbine is one of the 10 major technical equipment that are given priority by the country.It is a key development field of national equipment manufacturing industry, especially gas steam combined cycle units and integrated gasification gas steam combined cycle units.It is expected that with the rapid growth of China's energy demand and the large-scale development and utilization of natural gas resources, gas turbines are forming a "explosive growth" market.By 2020, the installed capacity of gas turbine combined cycle in China will reach 55 million kilowatts, 25 times the installed capacity of the same type built 50 years before 2000.It is conservatively estimated that PetroChina alone needs gas turbines worth 3 billion yuan every year.By 2015, the domestic market capacity of gas turbines will reach 30 billion yuan, while the international market capacity will reach 270 billion yuan.
In February 2023, the first domestic heavy-duty gas turbine with the highest energy efficiency level of air cooling will be successfully rolled out in Qinhuangdao, Hebei.[8]
On February 28, 2024, it was reported that the first prototype of the 300 MW Class F heavy gas turbine independently developed by China was put on the assembly line in Lingang, Shanghai.
