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We provide solutions such as open-frame gas generator sets, containerized gas generator sets, and silent gas generator sets. The power range of gas-powered products is 5kW-2000kW.
EN10-EN50 Eon engine platform, unit power 10kW-50kW; ES120-ES250 Steyr engine platform, unit power 120kW-250kW; EC50-EC500 Cummins engine platform, unit power 50kW-500kW; ED150-ED500 Deutz engine platform, unit power 150kW-500kW; EB600-EB1500 Baudouin engine platform, unit power 600kW-1500kW
Classification of Diesel Generator Sets
In addition, according to the purpose and use of diesel generator sets, they can be divided into standby generator sets, common generator sets, war-ready generator sets and emergency generator sets.
Generator Sets
1. Standby Generator Sets
Under normal circumstances, the power required by users is supplied by the city power. When the city power limit is disconnected or other reasons interrupt the power supply, the generator set is set up to ensure the basic production and life of users. This type of generator set is located in important power users such as industrial and mining enterprises, hospitals, hotels, banks, airports and radio stations where the city power supply is tight.
2. Common Generator Sets
This type of generator set operates all year round and is generally located in areas far away from the power grid (or city power) or near industrial and mining enterprises to meet the construction, production and living electricity needs of these places. At present, in areas with relatively rapid emergency development, common diesel generator sets with short construction periods are needed to meet the needs of users. This type of generator set generally has a large capacity.
3. War-ready generator sets
This type of generator set is used to supply power to civil air defense and national defense facilities. It has the nature of a standby generator set in normal times, and has the nature of a common generator set after the city power is destroyed in wartime. This type of generator set is generally installed underground and has a certain degree of protection.
4. Emergency generator set
For electrical equipment that will cause major losses or personal accidents if the city power is suddenly interrupted, emergency generator sets are often set up to provide emergency power to these equipment, such as fire protection systems, evacuation lighting, elevators, control systems of automated production lines, and important communication systems in high-rise buildings. This type of generator set needs to be installed with a self-starting diesel generator set, and the degree of automation is required to be high.
The above are some basic classifications of diesel generator sets. Users can choose suitable diesel generator sets according to their needs and suitable environments. For the use of diesel generator sets, in addition to the correct selection of matching models, regular maintenance is also required in later use.
Top 10 Diesel Generator Brands Diesel Generator Manufacturers Ranking
What brand of diesel generator set is good? The list of the top ten brands of diesel generator sets in 2024 has been released after professional evaluation! The top ten are: Caterpillar, Cummins, Volvopenta, Sanchong, TELLHOW, COOLTECH, FIRMAN, Weichai, Calsion, Foguang Power Generation, etc. The top ten brands of diesel generator sets and the list of famous diesel generator set brands are brands with good reputation, high popularity and strength. The ranking is in no particular order and is for reference only. Want to know what brand of diesel generator set is good? You can compare more and choose the one you are satisfied with! Diesel generator set brands belong to Class 7 of trademark classification.
The first! This generator set was successfully developed
On August 22, the Institute of Electrical Engineering of the Chinese Academy of Sciences learned that after five years of technical research and engineering construction, the first supercritical carbon dioxide solar thermal power generation unit was successfully developed. The third-party test results show that the power generation power, heat-to-work conversion efficiency and other indicators of the generator unit fully meet the requirements of the project task book.
It is reported that the generator unit was developed with the support of the “Research on Key Basic Issues of Supercritical Carbon Dioxide Solar Thermal Power Generation” project. The project recently passed the project performance evaluation organized by the National Natural Science Foundation of China. After five hours of defense and expert questioning, the expert group gave a high evaluation of the project and recommended its promotion and implementation.
In recent years, my country’s solar thermal power generation industry has shown a booming development trend, but the cost of solar thermal power generation has not fallen as expected. Supercritical carbon dioxide solar thermal power generation technology, as the most potential low-cost, high-efficiency and high-flexibility technology, has attracted widespread attention from global research institutions and industries.
“However, the core equipment used in supercritical carbon dioxide solar thermal power generation technology, such as high-temperature particle absorbers and supercritical carbon dioxide generators, are in the research and exploration stage worldwide.” said Wang Zhifeng, project leader and researcher at the Institute of Electrical Engineering of the Chinese Academy of Sciences.
Over the past five years, the project team has focused on engineering design, organically integrated basic theoretical research, technical equipment development and system integration, and actively promoted scientific research and empirical engineering construction.
“We have overcome the difficulties in designing and manufacturing core equipment such as solar high-temperature particle heat absorption, fluidized bed particle/carbon dioxide heat exchange, and 200-kilowatt supercritical carbon dioxide generator sets. We are the first in the world to realize the operation of supercritical carbon dioxide solar thermal power generation systems including high-coke ratio focusing fields, particle heat absorbers, particle/supercritical carbon dioxide heat exchangers, supercritical carbon dioxide compressor turbine units and high-speed motors.” Wang Zhifeng said that the project will effectively promote the development of my country’s “low-cost-high-efficiency-high-flexibility” solar thermal technology and provide technical support for the construction of my country’s new energy bases.
To create the “Jiangsu Model”, how does China National Petroleum Corporation help the province develop gas-electricity integration?
Since the beginning of summer, the Jiangnan region has been hot and humid, and the demand for electricity has continued to increase. In mid-August, in the machine room of Jiangsu Zhenjiang Gas Thermal Power Co., Ltd., a gas-fired generator set with a rated power of 485 megawatts was running at high speed. Here, the natural gas supplied by the natural gas sales company converts the heat energy generated by combustion into mechanical energy, drives the generator to rotate, and generates electricity. These clean electricity flows into the power grid continuously, providing thousands of households with a “cooling recipe” to relieve the summer heat.
In recent years, natural gas power generation has received more and more attention on the stage of power supply. As one of the provinces that actively promotes the integration of gas and electricity, Jiangsu Province has always been at the forefront of the country in the natural gas power generation industry. Why is natural gas power generation so popular in Jiangsu? What kind of development process has natural gas power generation in Jiangsu experienced? What role has the natural gas sales company, as the main gas supply, played in ensuring supply? What practical experience has been formed? With these questions, the reporter conducted interviews and investigations to explore the “Jiangsu example” of gas-electricity integration development.
In 2023, my country’s natural gas consumption continued to grow. Among the four major gas-using areas of urban gas, industry, power generation, and chemical industry, power generation gas accounted for about 17%. From the perspective of Jiangsu Province’s natural gas consumption in 2023, power generation gas accounted for 30.4%, far exceeding the national average. The information obtained by the reporter during the interview showed that Jiangsu has a high degree of gas-electricity integration and has made great efforts to promote natural gas power generation.
Jiangsu’s gas-fired power generation is closely related to Jiangsu’s regional characteristics. A relevant person in charge of the Economic Operation Bureau of the Jiangsu Provincial Development and Reform Commission said: “Jiangsu has a developed economy, but a dense population and a high per capita energy consumption base. It faces challenges such as energy shortages and great pressure on environmental protection. The orderly promotion of gas-fired power generation projects is of great significance to promoting energy conservation and emission reduction and ensuring power supply.”
Tracing the development of gas-electricity integration in Jiangsu, the reporter found that Jiangsu’s previous power generation structure was relatively simple and highly dependent on coal-fired power. In 2004, the West-East Gas Pipeline was put into operation, allowing the eastern region to use the natural gas produced and transported by the Tarim Oilfield of China National Petroleum Corporation, which provided an opportunity for Jiangsu to optimize its power structure. Since then, natural gas pipelines, LNG receiving stations and corresponding supporting facilities have been gradually established in Jiangsu Province, allowing the natural gas industry to develop vigorously from scratch.
Thanks to the development of the natural gas industry, gas-fired power plants have sprung up like mushrooms after a rain. In 2005, the gas-fired power generation unit of Zhangjiagang Huaxing Electric Power Co., Ltd. was successfully connected to the grid once, becoming the first gas-fired power plant in Jiangsu. To date, Jiangsu has 39 power plants with gas-fired power generation capabilities.
Zhangjiagang Huaxing Electric Power Co., Ltd. is the first power plant supplied by PetroChina in Jiangsu. From supplying gas to 1 power plant to supplying gas to 37 power plants, PetroChina supplies gas to almost all gas-fired power plants in Jiangsu. Since the gas supply began in 2005, PetroChina’s resource input in the gas-fired power market in Jiangsu Province has increased year by year, reaching nearly 10 billion cubic meters in 2023, accounting for more than 90% of the gas used for power generation in Jiangsu Province.
During the investigation, the reporter walked into one of the power plants-Nanjing GCL Gas Turbine Thermal Power Co., Ltd. (referred to as Nanjing GCL). There are no towering chimneys here, nor can you see the rising “white smoke”. According to Xiao Youjun, director of the business planning department of Nanjing GCL, this is a power plant that “consumes” natural gas completely. Compared with coal-fired power plants of the same capacity, sulfur dioxide emissions have been reduced by about 90%, and smoke emissions have been reduced by about 100%, with significant benefits in environmental protection.
Facts have proved that in the past 20 years, Jiangsu has made every effort to promote the optimization of energy structure and green energy transformation, and the natural gas power generation industry has developed steadily. The development of PetroChina’s natural gas power generation-related business in Jiangsu has also achieved a huge leap.
Data shows that Jiangsu Province is one of the provinces in China with a large number of power plants and gas resources for power generation, which shows the natural gas sales company’s high attention to the natural gas power generation market in Jiangsu and its confidence and determination to find a path for the integration of gas and electricity.
Common faults and causes of gas generators
Common fault problems and solutions of gas generators – The China-Myanmar oil and gas pipeline uses Wilson gas generators as the power supply source for stations along the line. During the normal operation of the gas generator, in order to ensure the uninterrupted supply of power to the station, attention should be paid to the inspection of the gas generator and timely troubleshooting of the gas generator fault. This article combines the actual operation experience of Wilson gas generators in stations along the China-Myanmar oil and gas pipeline, analyzes the common fault problems of Wilson gas generators, and proposes some preventive measures.
There are 22 Wilson gas generator sets in the stations along the Myanmar section of the China-Myanmar oil and gas pipeline. Some of the stations are located in remote mountainous areas and islands. There is no access to external electricity in these areas, so Wilson gas generators carry the only power supply for the stations. Long-distance oil and gas pipelines have strict requirements on the power system. Gas generator sets and UPS power supplies are set up in stations along the line as the power supply of the stations. UPS is responsible for the uninterrupted power supply needs of the core key equipment of the stations. The gas generator sets used in stations along the China-Myanmar oil and gas pipeline are mainly Wilson PG345B3 and Wilson PG375B3. Wilson gas generator sets are composed of Perkins engines, Leroy-Somer generators and Wizards intelligent control systems, and Wilson manufacturers are responsible for assembly.
Failure types and cause analysis of gas generators
01 High cooling water temperature
Phenomenon: The station control staff found that the water temperature of the gas generator was high. The relevant personnel immediately went to the site to check the generator set. The cooling system such as the fan was normal, and there was no alarm on the control panel. Half an hour later, the upper computer had an alarm for the high cooling water temperature of the gas generator, which caused the shutdown.
Cause analysis of the high cooling water temperature: The cooling water temperature of the gas generator is around 89℃ during normal operation. When the load increases significantly, the cooling water temperature rises immediately, exceeding the critical value and causing an alarm shutdown.
Other reasons: (1) Scaling in the cooling water pipeline leads to poor cooling water heat dissipation; (2) Cooling fan motor is damaged, leading to poor heat dissipation; (3) The thermostat is stuck or not opened due to other reasons; (4) Water leaks in the cooling water pipeline or joints, and the cooling water level is reduced due to natural loss, resulting in cooling water shortage; (5) The cooling water temperature sensor is faulty, resulting in inaccurate detection results.
02 Power conversion module failure
Phenomenon: The on-site gas generator Wizard control screen displays a “reverse power” fault alarm and shuts down. The generator power curve of the station control host computer has an abnormal jump phenomenon at the moment of shutdown.
Cause analysis: Relevant personnel checked the on-site wiring cabinet and tested the power conversion module. There was a problem with the 4-20 mA output. After analysis, it may be that the impact current caused the power converter failure.
Motor control failure
Phenomenon: The Wizard control screen displays the “Motor Control Fault” fault alarm information.
Cause analysis: According to the message on the display, the motor control cabinet of the gas generator set was opened. After checking, loose wiring and damage to other components were eliminated one by one. The IMO TDMD-X delay relay was tested and it was found that the delay relay ATR could not be normally attracted after powering on for a specified time, confirming that it was a delay relay failure. After replacing the delay relay, the gas generator ran normally.
Other cause analysis: cooling fan failure. Due to the long-term operation of the cooling fan, the bearing may be deformed and cause the fan to not work. This situation will also cause the motor control fault alarm.
03 Start failure
Phenomenon: The gas generator automatically stops after starting and idling for a while.
Cause analysis: (1) The battery voltage is not enough to start the gas generator; (2) The pipeline between the gas pipeline of the gas generator and the combustion chamber is rich in gas and lacks air, which is not enough for ignition and combustion; (3) Ignition system failure, such as ignition coil failure, spark plug dampness, and plug end pore blockage; (4) Starting motor failure; (5) Insufficient gas source pressure; (6) The hot standby system is not in use, resulting in too low temperature of the gas generator body; (7) In a damp environment, attention should be paid to regular warm-up of the gas generator.
04 Knocking
Phenomenon: The “Knocking” fault alarm message appears on the field control screen.
Cause analysis: (1) Too much carbon deposits in the cylinder combustion chamber, which easily forms a high-temperature ignition point on the carbon deposit surface; (2) The ignition advance angle is too advanced, resulting in the ignition of the mixed gas before the time when the piston reaches the top dead center, so that the pressure rises sharply during the piston compression stroke, causing the occurrence of deflagration. At the same time, the pressure generated by the deflagration acts on the piston, affecting the piston stroke, causing knocking; (3) The cooling water temperature is too high, resulting in high engine body temperature, poor heat dissipation, high temperature and knocking; (4) Other situations such as incorrect air-fuel ratio.
05 The unit cannot be loaded normally
Phenomenon: The unit cannot be synchronized during the cutting and loading process and cannot be operated with load. Cause analysis: (1) Is the gas generator output air switch closed? (2) Is the reset button of the generator output circuit breaker system GCB popped out? If it popped out, press it directly, and then perform synchronous parallel loading.
The world’s first 5MW offshore high-temperature flue gas waste heat power generation device was delivered
On August 13, the world’s first 5MW offshore high-temperature flue gas waste heat power generation device, independently developed by CNOOC and China Shipbuilding and constructed by COOEC, was completed and delivered in Tianjin. This marks that my country’s offshore oil and gas field power stations have made significant progress in the utilization of flue gas waste heat, which is of great significance to the realization of green and low-carbon development of offshore oil and gas fields.
The power station is the “heart” of the offshore platform. It is usually powered by the combustion of self-produced oil and gas. In this process, a large amount of high-temperature flue gas is emitted, which is the main source of carbon emissions in offshore oil and gas development. How to reduce high-temperature flue gas emissions has become a problem that plagues the green production of offshore oil and gas platforms. To this end, COOEC has created a “magic weapon” to conquer it – a high-temperature flue gas waste heat power generation device.
The waste heat power generation device uses the waste heat of high-temperature flue gas generated by the operation of the power station as a heat source. The organic medium circulating in the device drives the expander to generate electricity, which can directly convert the waste heat into clean electricity. After the power generation device is applied, the comprehensive utilization of flue gas waste heat of the main power station of the offshore oil and gas field will be realized. The comprehensive energy efficiency of the main power station is expected to increase by 7%, effectively saving the consumption of crude oil and natural gas in the oil and gas field.
The device will be used in the Wenchang 9-7 oilfield development project in the future. It is estimated that the annual power generation of the device can reach 40 million kWh after it is put into use, and it can save about 300 million cubic meters of natural gas consumption in 20 years of operation.
Previously, there was no precedent in the field of offshore high-temperature flue gas waste heat power generation applications at home and abroad. CNOOC Research Institute, Limited Zhanjiang Branch, and Offshore Oil Engineering jointly promoted the formation of independent technical service capabilities for the entire chain of equipment development, skid-mounted manufacturing, and testing, and created an independent and controllable equipment system.
This technology can be widely used in my country’s offshore oil and gas platforms, promoting offshore oil and gas fields to achieve energy conservation and emission reduction, cost reduction and efficiency improvement goals during the development process, and injecting new momentum into the green and low-carbon development of the offshore oil industry.
In addition, it helps the normal operation of various mechanical equipment on the offshore platform, and also provides energy supply for the pair of offshore equipment, so that the offshore platform can continue to work in a healthy cycle.
Cooling technology for gas generator room in Central Asia pipeline gas transmission station
The Central Asia Natural Gas Pipeline is an important strategic energy channel in my country. The gas transmission station is powered by gas generators throughout the year. Due to the high temperature in the generator room in summer, the generator is underpowered or even shut down, resulting in the shutdown of the compressor unit, which will have a serious impact on the safe operation of the Central Asia pipeline. According to the thermodynamic environmental characteristics of the generator room, the heat load and cooling air volume required for cooling the generator room are calculated. The fluid mechanics software FLUENT is used to perform numerical simulation on the cooling effect of the improved ventilation system in the generator room. Field test data show that the temperature of the generator room and the generator intake temperature are both controlled below 44 ℃, and the generator has not been shut down due to high suction temperature. The economic benefits of this measure are significant, the efficiency of the gas generator is increased by 11%, the gas fee is saved by 596,400 yuan per year, and the pipeline fee is increased by 63,100 yuan. The research results have application and promotion value for energy conservation and emission reduction of gas transmission stations in the special environment of Central Asia.
The Central Asia Natural Gas Pipeline (Uzbekistan Section) is mostly desert Gobi along the line. Due to the poor reliability of municipal power supply lines, gas transmission stations are powered by gas generators. The generator has repeatedly experienced the problem of automatic load shedding, especially in summer when the average temperature of the generator room reaches 50℃. The high temperature causes the generator to be insufficiently powered or even shut down, which in turn causes the compressor unit to shut down. The operation of gas generator sets in a high temperature environment may cause engine component failure, sensor signal failure, water circulation failure and antifreeze loss, which will reduce power generation efficiency, increase maintenance costs, and even cause safety accidents [1]. In order to eliminate the safety hazards of gas transmission stations and ensure the safety of operators, it is necessary to study the thermodynamic environmental characteristics of the gas generator room of the gas transmission station and formulate effective cooling measures.
In view of the indoor thermodynamic environmental characteristics of civil buildings, systematic research has been carried out in China, including heat source height, heat source intensity, heat source area, air inlet and outlet location and effective area, air supply temperature, ventilation volume and other factors. Sui Xuemin [2] studied the influence of heat source intensity on indoor thermal stratification under the action of thermal pressure natural ventilation in civil buildings. KAYE [3] expanded the indoor single point source model into a line source model and a surface source model. AWAD studied the influence of the position of air inlet and outlet on the flow characteristics of thermal stratification[4]. Liu Meng et al.[5] analyzed the values of air supply temperature and air supply speed corresponding to different heat source thermal indicators (heat dissipation per unit building area) from the perspective of thermal stratification height.
Gas generator room is different from civil buildings. It belongs to industrial plant with heat source, that is, there is a high-temperature heat source and a large amount of waste heat is emitted. Thermal pressure ventilation is a relatively recognized and effective method to remove indoor waste heat and pollutants. Cao Weixue[6] used CFD numerical simulation method to increase the openable area of external windows and optimize the design type of roof skylights to effectively increase the natural ventilation volume and reduce the internal temperature of industrial plants. Wan Xin et al.[7-8] studied the influence of heat source distribution and air inlet and skylight exhaust structure on natural ventilation effect in industrial plants. Liu Yuanlu[9-10] proposed a method to improve the natural ventilation effect of industrial plants by tunnel ventilation system.
1. Selection of cooling technology scheme
1.1 Basic information of research object
The WKC1 station, the first station of the China-Ukraine natural gas pipeline A and B lines, was selected as the research object. The station was put into operation in 2009 and is equipped with three GE Jenbacher natural gas generators, two of which are in operation and one is in hot standby. The power of a single generator is 1,415 kW. The generator room is 24 m long, 12 m wide and 5.7 m high. The original ventilation system design scheme is natural ventilation (door is always open). The generator plant is a large space industrial building with heat source. The thermal environment characteristics are as follows: (1) The building is tall and the indoor volume is larger than that of conventional buildings, but the working area is located within a height range of 2 m at the bottom of the space.
(2) Affected by the heat emitted by the generator and facilities, the hot air flow rises, the vertical temperature gradient is large, and the air stratification phenomenon is obvious.
(3) Compared with the heat dissipation of the generator facilities, the temperature difference caused by outdoor solar radiation can be ignored.
1.2 Technical route
According to the thermodynamic environmental characteristics of the generator room, the heat load and cooling air volume required for cooling the generator room were calculated, and a variety of exhaust cooling technical solutions were compared. The fluid mechanics professional analysis software FLUENT was used to perform numerical simulation on the ventilation effect of the ventilation system with optimized design and improvement, verify the ventilation and cooling effects, and provide a basis for the energy-saving operation of the ventilation system.
1.3 Comparison of ventilation solutions for generator rooms
GB 51131-2016 “Technical Specifications for Gas-fired Combined Cooling, Heat and Power Engineering” stipulates that natural ventilation should be used in the factory. When natural ventilation does not meet production requirements, mechanical ventilation or a combination of natural ventilation and mechanical ventilation should be used. The gas generator room has a large heat dissipation and requires a large amount of ventilation. Especially in summer conditions, natural ventilation is difficult to meet the ventilation and heat dissipation requirements, and other ventilation solutions should be adopted.
Solution 1: Natural air intake and mechanical exhaust solution.
Solution 2: Mechanical air intake and natural exhaust solution.
Solution 3: Mechanical air intake and mechanical exhaust solution.
From the perspective of construction investment and operation cost, Scheme 1 is the lowest, followed by Scheme 2, and Scheme 3 is the highest; from the perspective of operation and management difficulty, Schemes 1 and 2 are relatively simple, while Scheme 3 requires high professional quality of personnel; from the perspective of operation effect, Scheme 3 is the best, followed by Scheme 2 and Scheme 1. Considering the characteristics of various schemes and combining the requirements of GE generator supplier to ensure a slightly positive pressure indoors, the selected ventilation system for the gas generator room is mechanical air supply and mechanical exhaust. Two DBF low-noise variable air volume fan boxes are installed for air supply. Since the WKC1 compressor station is located in the desert and has strong winds and sand, if the fan is used to directly supply air, the air pollution in the plant will be very serious. For this reason, the fan box is used for air supply, and then the explosion-proof axial flow fan is used to exhaust it to the outside. A filter is set in the fan box to reduce the impact of sand and dust on the equipment. Under the combined effect of the wind pressure and thermal pressure provided by the fan, the incoming air enters the room to form a hot air flow.
1.4 Calculation of heat load and required cooling air volume in the generator room
The heat generated by the gas generator is calculated according to the following formula: See formula (1) in the figure.
Where: Q1 is the heat output of the gas generator, kJ/h; Nn is the rated power of the gas generator, kW; B is the gas consumption rate of the gas generator, m3/(kWh); q is the calorific value of natural gas, taken as 35.588 MJ/m3 (standard condition); η1 is the heat coefficient of the gas generator dissipated to the air, %.
The heat dissipation of the generator is calculated according to the following formula: See formula (2) in the figure.
Where: Q2 is the heat dissipated from the generator to the air, kJ/h; Pn is the rated output power of the generator kW; η2 is the generator efficiency, %.
The difference between the flue gas temperature in the exhaust pipe and the temperature in the main plant is 1 ℃. The heat dissipation of 1 m exhaust pipe is calculated according to the following formula: See formula (3) in the figure.
Where: q3 is the heat dissipation of the exhaust pipe, kJ/(mh℃); λ is the thermal conductivity of the insulation material, kJ/(mh℃); d1 is the outer diameter of the exhaust pipe, m; d2 is the outer diameter of the insulation layer, m; a2 is the heat dissipation coefficient of the outer surface of the insulation layer, kJ/(m’2h℃).
The heat dissipation of the exhaust pipe is calculated according to the following formula: see formula (4) in the figure.
Where: Q3 is the heat dissipation of the exhaust pipe, kJ/h; L is the length of the exhaust pipe in the plant, m; tn is the air temperature in the plant, ℃; t1 is the exhaust temperature, ℃.
The heat load in the gas generator room is the sum of the above three parts: see formula (5) in the figure.
Where: Q is the heat load in the plant, kJ/h.
The cooling air volume of the gas generator plant is calculated according to the following formula: see formula (6) in the figure.
Where: V is the cooling air volume required by the plant, m3/h; γ is the intake and exhaust air density, kg/m3; c is the specific heat capacity of the intake and exhaust air, kJ/(kg·℃); t1 is the air intake temperature, ℃; t2 is the air exhaust temperature, ℃.
According to equations (1) to (6), the heat dissipation of a single unit is calculated to be 152 kW. There are three units in the generator plant, two in operation and one in standby, with a total heat dissipation of 304 kW. The air intake temperature is taken as the highest ambient temperature in summer, 43 ℃. When the intake temperature reaches the highest value, the room temperature 1 m away from the generator set, that is, the air exhaust temperature, is measured to be an average of 50.8 ℃. Taking into account the ventilation design margin, 50 ℃ is selected as the exhaust temperature, and the calculated ventilation volume is 1.32×10’5 m‘3/h.
Access system of trigeneration energy station at an airport and selection of gas generator sets
This paper introduces the access system and gas generator set selection of a trigeneration energy station at an airport, including the operation mode of the power generation system, the setting of the access system, the relay protection measures of the grid-connected system, the selection of gas generator types, the grouping of generator sets, the number of units and the selection of single-unit capacity, etc., which can provide reference for the design of similar projects.
The trigeneration energy station project of an airport is located in a provincial capital city in western my country, and is used to supply electricity, hot water and heating to the airport area. When the project was designed, the total construction area of the airport area was 320,000 m’2, the annual electricity consumption was about 31.9 MkWh, and the annual electricity fee was about 25.117 million yuan. Due to the planned expansion of the airport area, it is expected that the total construction area of the airport area will reach 420,000 m’2 after the energy station is completed.
The natural gas price is low in the project location, and the city electricity is priced by time of use. After the completion of the trigeneration energy station, natural gas will be used for self-generation during peak electricity price and normal hours, and the waste heat generated by power generation will be used to heat the boiler feed water, which will produce good economic benefits; the heating time at the project site is long, and clean energy must be used for heating due to environmental protection reasons. The use of gas boilers for heating will produce good social benefits. After technical and economic comparison, the cost of self-generation is equivalent to the off-peak electricity price, so the project does not consider self-generation during off-peak hours.
After technical and economic comparison, the energy station of the project has a total of 4 2 MW gas internal combustion engines (divided into 2 groups) to supply power to all the electricity loads of the airport; in addition, 2 20 t gas boilers are set to output hot water to the airport area for hot water and heating. The exhaust gas emitted by the gas internal combustion engine is used to preheat the feed water of the gas boiler to achieve cogeneration of heat and power. This paper analyzes the key technical issues of electrical design in this project.
1 Power supply and distribution system
1.1 Current status of power supply and distribution system
The airport currently has one 35/10.5 kV central substation (referred to as “central substation”), which is powered by two 35 kV municipal power sources (Kongchuan Line and Longzhong Line). A total of two 35/10.5 kV transformers are installed, and the capacity of each transformer is 10,000 kVAo. The central substation has two sections of 10 kV busbars (10 kV I section and 10 kV / section respectively), and the two transformers are connected to one section of the 10 kV busbar. The two sections of 10 kV busbars are usually operated separately. When one section fails, the other transformer can meet the power demand of all loads. The central substation feeds 40 10 kV lines to each 10/0.4 kV substation.
1.2 Operation mode of power generation system
Due to the restrictions of the local power supply department on the access to the enterprise joint supply system, the joint supply system of this project adopts the grid-connected operation mode and does not operate on the grid.
1.3 Access system settings
The access system should be designed according to the capacity of the generator set and the main connection form of the power distribution system. The central substation of this project feeds as many as 40 10 kV lines, and there are many lower-level 10/0.4 kV substations, and the power load is dispersed throughout the airport area. In order to ensure that the generator set of the combined power supply system can effectively supply power to all power loads, the project will set the grid connection point at the 10.5 kV bus of the central substation. The 10.5 kV I-section bus and the 10.5 kV/section bus are respectively connected to the generator set power supply of the combined power supply system. The combined power supply system can supply power to all power loads in the airport area.
The output voltage level of the generator set should be determined according to factors such as generator capacity, power load requirements, and power supply distance. The single-unit capacity of the generator of this project is 2 MW, and the grid connection location is the 10.5 kV bus of the central substation. The distance from the energy station to the grid connection point is about 800 m. Taking the above factors into consideration, the output voltage of the generator set is 10.5 kV.
After the 10.5 kV busbar of the central substation is connected to the power generation power supply of the combined power supply system, the power supply of the power supply system is increased from 2 to 4, and the reliability of the system power supply is improved. The schematic diagram of the 35/10.5 kV distribution system is shown in Figure 1.
1.4 Relay protection measures for the grid-connected system
The project sets up an automatic monitoring integrated system (hereinafter referred to as the “monitoring system”), and uses a PLC controller to control and protect the power generation, transmission and distribution systems of the combined power supply system.
(1) Automatic synchronization measures. The monitoring system adjusts the output parameters of the combined power supply system generator set according to the voltage, frequency, phase and other parameters of the 10.5 kV busbar of the central substation (collected by the intelligent measurement and control instrument), so that it is automatically synchronized with the parameters of the 10.5 kV busbar of the central substation and the grid-connected circuit breaker (located in the 10 kV high-voltage distribution room of the energy station) is automatically switched on and off to realize the grid-connected operation of the combined power supply system generator set.
(2) Reverse power protection measures. A “reverse power protection device” is set at the two 35 kV mains power supply lines as a control and protection device for grid connection and non-grid connection, ensuring that the combined power supply system only receives power and does not transmit power to the public power grid. The intelligent measurement and control instrument detects the active power transmitted from the 35 kV mains power grid to the airport in real time. When the active power is close to 0, the monitoring system automatically controls and reduces the output power of the generator set; when the active power is 0, the reverse power protection device automatically disconnects the generator set grid connection circuit breaker (located at the 10 kV I section bus and 10 kV/section bus of the central substation) to prevent the generator from transmitting power to the 35 kV public power grid. To ensure the reliability of the airport power supply, the reverse power protection device only acts on the grid connection circuit breaker that disconnects the generator set, and does not act on the incoming circuit breaker that disconnects the 35 kV mains power of the central substation.
(3) Generator set start-stop and output power control measures. The monitoring system can realize the start-stop control, output power control, and grid connection and disconnection control of the generator set. The monitoring system monitors the active power and related parameters of the main incoming line circuit of the 35 kV substation in real time, starts and stops the gas-fired generator set according to the control logic, automatically adjusts the output power of the generator set, and automatically switches the generator set grid-connected circuit breaker.
2 Selection of gas generator set types
2.1 Main types and characteristics of generator sets
The main power generation equipment of the combined power generation system includes small gas turbines (hereinafter referred to as “gas turbines”), gas internal combustion engines and micro-turbines. Reasonable selection of the type of generator set is the key to improving equipment utilization, energy efficiency and economy.
2.2 Characteristics of gas turbines
(1) Gas turbines are rotary power equipment that converts thermal energy into mechanical energy using continuous flowing gas as the working fluid, including compressors, combustion chambers, auxiliary equipment, etc., with the advantages of compact structure, simple operation and good stability.
(2) Gas turbines have large power and are mainly used in large and medium-sized power plants.
(3) When the single unit capacity is below 4 MW, the power generation efficiency of gas turbines is low and the economy is poor.
2.3 Characteristics of gas internal combustion engines
(1) Gas internal combustion engines are equipment that mixes liquid or gas fuel with air and directly inputs it into the cylinder for combustion and generates power. They are heat engines that convert thermal energy into mechanical energy. They have the advantages of small size, high thermal efficiency and good starting performance.
(2) Gas internal combustion engines are less affected by the geographical environment and can operate normally under high temperature and high altitude. (3) Gas internal combustion engines have low power and are mainly used in small distributed power stations. When the power generation is low, the power generation efficiency of gas internal combustion engines is high, which is more suitable for systems with a single power generation of less than 4 MW.
2.4 Characteristics of micro-gas turbines
Micro-gas turbines are micro gas turbines. The power of a single unit is generally less than 300 kW, and its characteristics are basically the same as those of gas turbines. The power of a single micro-gas turbine is too small to be applied to this project.
2.5 Thermal efficiency and power generation efficiency characteristics of various types of generator sets
(1) The total thermal efficiency (the sum of thermal efficiency and power generation efficiency) of gas turbines and gas internal combustion engines is roughly the same.
(2) The power generation efficiency of gas internal combustion engines is higher than that of gas turbines.
(3) The thermal efficiency of gas turbines is higher than that of gas internal combustion engines.
2.6 Waste heat characteristics of various types of generator sets
(1) The flue gas temperature of gas turbine units is relatively high (above 450 J), which is mainly used to produce high-pressure steam and can also drive steam turbine generator sets to generate electricity.
(2) The waste heat of gas internal combustion units is divided into two parts: one part is the waste heat of cylinder jacket cooling water, which has a lower temperature and is mainly used for heating and preparing domestic hot water; the other part is the waste heat of flue gas, which has a temperature between 400 and 500 J and can be used to drive absorption chillers and produce steam.
2.7 Determination of generator set type
When determining the type of generator set, factors such as the cold, heat and electricity load, operation mode, matching of waste heat medium parameters with waste heat utilization equipment, and operation economy should be comprehensively considered. This project has the following characteristics:
(1) The unit capacity of the generator set is about 2 MW.
(2) The operation mode is grid-connected.
(3) The altitude of the project site is relatively high, about 2,000 m.
(4) The part that generates economic benefits is mainly the amount of electricity generated, and units with high power generation efficiency should be selected.
(5) The temperature requirement for waste heat (flue gas waste heat, cooling water waste heat) is not high, and waste heat is only used to heat boiler feed water.
Taking the above factors and the characteristics of various types of generator sets into consideration, this project selects gas internal combustion engines as generator sets.
3 Determination of the number of generator sets and the capacity of a single unit
When selecting the number of generator sets and the capacity of a single unit, factors such as the high load rate when the generator is working, the generator set should be able to adapt to the load changes of the user, the full utilization of waste heat, and the high return on investment should be considered. The part that generates economic benefits in this project is mainly the power generation. The annual total power generation should be maximized within the limited investment as the overall design goal, and the unit capacity utilization rate should be as high as possible.
3.1 Single unit load rate characteristics of gas internal combustion engines
When the load rate of a gas internal combustion engine is above 50%, the power generation efficiency is high; when the load rate is below 50%, the power generation efficiency is low, and the damage to the unit is large. Generally, it needs to be shut down and cannot generate electricity. Therefore,
the gas internal combustion engine can only operate in the load range of 50% to 100% of the power generation load rate.
3.2 Analysis of airport power load
Under certain total investment, if the power of a single generator is too small and the total power is small, when the power load is at peak, the total power generation capacity is insufficient and more city power is used, resulting in poor economic benefits; if the power of a single generator is too large, when the power load is at low, the load is less than 50% of the single generator capacity, and the generator set needs to be shut down and city power needs to be used, resulting in a reduction in the total power generation, low unit capacity utilization, and low return on investment.
Therefore, to determine the total installed capacity, single unit capacity and number of generators, it is necessary to analyze the power load of the project, and to statistically analyze the values of the power load at all times of the day and throughout the year.
3.3 Electricity prices at each time period and their impact on unit capacity
The city power price of the airport is a time-of-use price, and the electricity prices at each time period are shown in Table 1.
Since the valley electricity price is low and close to the cost of self-generated electricity at the energy station, the project does not consider generating electricity at valley time (23 00~7 00), and the power load analysis and generator set selection are considered according to the (peak price + parity) time period.
Gas generator set High efficiency new energy generator
The engine and the generator are coaxially connected and placed on the chassis of the whole machine. Then the muffler and the speed regulator are connected to the engine. The gas source is passed into the gas channel in the engine, connected to the recoil starter with a pull rope on the engine and the voltage regulator connected to the output end of the generator. The combustible gas stored in the gas source is natural gas, liquefied petroleum gas, or biogas. The use of gas generator sets reduces environmental pollution compared with gasoline generator sets and diesel generator sets. It is an environmentally friendly and energy-saving generator. Moreover, it has a simple structure, is safe and reliable to use, and has stable output voltage and frequency.
The filter device is used to protect the valve of the gas pipeline, and the aperture of the filter should not be greater than 1.5MM. The gas pressure stabilizing filter device is the main and key equipment in the gas transmission and distribution process. It mainly undertakes the functions of pressure regulation and pressure stabilization, and also undertakes one or more functions such as filtering, metering, odorization, and gas distribution.
The fluctuation of the outlet pressure of the pressure stabilizing valve should not exceed ±5% within the entire combustion regulation range. If the valve train is equipped with an independent pressure regulating valve, an independent filter device should be installed at the front end of the air inlet to avoid clogging the air pipe in the pressure regulating valve.
[Advantages of gas generators]
1. Good power generation quality
Since the generator only rotates when working, the electric adjustment responds quickly and works very smoothly. The output voltage and frequency of the generator are highly accurate and have small fluctuations. When the load is suddenly increased by 50% and 75%, the unit is very stable. It is better than the electrical performance indicators of diesel generator sets.
2. Good starting performance and high starting success rate
The time from cold start to full load is only 30 seconds, while the international regulations stipulate that diesel generators can be loaded for 3 minutes after successful start. The gas turbine generator set can ensure the success rate of starting under any ambient temperature and climate.
3. Low noise and low vibration
Since the gas turbine is in a high-speed rotation state, its vibration is very small, and the low-frequency noise is better than that of diesel generator sets.
4. The combustible gas used is a clean and cheap energy source
Such as: gas, straw gas, biogas, etc., the generator sets using them as fuel are not only reliable and low-cost, but also can turn waste into treasure without causing pollution.
Gas generator sets can be used in a variety of scenarios, especially for powering mining machinery. For example, more and more pure electric mining machinery and equipment, such as mobile crushers, have been upgraded from the original diesel version to a pure electric new energy version. And it can also power the maintenance equipment of mining machinery, such as a series of facilities such as equipment for metal additive repair of crusher linings.
The scope of application of gas generator sets will become wider and wider.
China’s gas generator industry: rise and challenges
Chinese gas generator manufacturers have emerged in the global market, but there is still a gap between them and international brands in terms of technology level, product quality, market competitiveness and service level. It is necessary to strengthen technological innovation, quality improvement and service optimization to narrow the gap and contribute more.
In the global gas generator market, international brands such as Cummins, Caterpillar and Volvo have always occupied a pivotal position. However, in recent years, with the rapid development of my country’s manufacturing industry, my country’s gas generator manufacturers such as Weichai, Jichai Environmental Energy, Yuchai, etc. have also emerged and gradually emerged in the global market.
Standing proudly at the top of the industry, Weichai enters the era of gas power 4.0
Weichai released the world’s first diesel engine product with a thermal efficiency exceeding 53.09%, which attracted the attention of the industry. Subsequently, a new generation of gas-powered new products was launched, which led the industry in power, economy and reliability, filling the market gap. Weichai has been deeply involved in the internal combustion engine industry, achieved independent innovation, occupied a leading position in the market, and opened a new chapter in green logistics and transportation.
Be brave to stand at the forefront. Since April 2024, Weichai has released the world’s first diesel engine product with a thermal efficiency exceeding 53.09%, which has attracted much attention in the industry. Recently, Weichai’s 4.0 gas power new product was launched, marking that Weichai has once again stood at the top of the industry in the field of engines.
On May 23, Weichai’s new generation 13L/15L/17L NG-4.0 gas power new product launch conference was held in Shanghai. Relevant leaders from various OEMs, dealers from many places across the country, major customer representatives and media reporters attended the event.
Following the market trend, Weichai launches gas power 4.0 products
Entering 2024, the “heat” of the natural gas heavy truck market remains high. Data shows that the actual sales of natural gas heavy trucks in 2023 will exceed 150,000. At the same time, the penetration rate of natural gas engines has reached 70%. That is to say, for every 10 heavy trucks sold, there are 7 gas vehicles, which fully demonstrates the high recognition of natural gas engines by customers.
According to industry experts, with the gradual improvement of gas station construction, the further widening of the oil and gas price difference, coupled with my country’s implementation of the “international oil price” mechanism, the international “ban on combustion” process, and the promotion of the “3060” dual-carbon strategy, these will be long-term benefits to the natural gas heavy truck market, and the natural gas engine market will still have great growth opportunities in 2024.
Facing the opportunities in the commercial vehicle industry in 2024, Weichai has created a new generation of WP13NG-4.0, WP15NG-4.0, and WP17NG-4.0 gas-powered products. The new products are optimized for various working conditions such as composite transportation, trunk transportation, and mountainous plateaus, and have achieved significant improvements in power, economy, and reliability. In terms of technical indicators and quality, they are fully ahead of their peers.
Among them, WP13NG-4.0 is a special power for composite transportation high-horsepower gas tractors. The power is upgraded to 540 horsepower, the peak torque is 2600N·m, the B10 life reaches 1.8 million kilometers, and the power reserve is leading. In addition, the lightweight design is a major feature of this engine. It adopts a lightweight and modular design, with a more compact structure, higher engine strength, and convenient and quick maintenance. It has been verified in harsh “three highs” environments such as plateaus, high temperatures, and high cold.
WP15NG-4.0 is a special power for high-horsepower gas tractors for trunk transportation. Its rated power is up to 630 horsepower and its peak torque is 2800N·m. With the support of proprietary structure and special technology, the combustion responsiveness is better; it adopts pulse exhaust system, efficient mixing structure, and fast combustion technology to improve thermal efficiency and greatly reduce gas consumption; it adopts a new generation of NVH technology to improve driving experience in all aspects and create a comfortable driving environment. With the support of special technologies such as strong tumble intake organization technology, high turbulence energy fast combustion technology, and anti-fire advanced ignition technology, this engine has the industry-leading advantages in power, quality, and energy saving.
WP17NG-4.0 gas engine is mainly suitable for mountainous and plateau conditions. As the world’s largest natural gas engine, it has a rated power of up to 700 horsepower and a peak torque of 3200N·m, making it easy to travel across the country. In addition, the WP17NG-4.0 gas engine adopts the design of low-wear and low-power moving parts, and is supported by a number of high-thermal-efficiency technologies; it carries out powertrain matching optimization, and finely calibrates the speed, gear, and speed ratio combination to form a differentiated advantage of high horsepower and low gas consumption; it insists on reliability first, high-strength body structure design, and tends to operate in the low-load range. It has passed the 10,000-hour durability of the whole machine and has undergone the “three highs” environment verification, reaching a service life of 1.8 million kilometers.
The first domestic megawatt-class natural gas pressure differential generator set was successfully put into operation
Deepen energy conservation and carbon reduction measures to help the green and low-carbon transformation and development of the natural gas sector. On May 17, the first domestic megawatt-class natural gas pressure differential generator set developed by Dongfang Turbine Co., Ltd. of Dongfang Electric Corporation was successfully put into operation at the Suqiao gas storage reservoir in the North China Oilfield, marking a breakthrough in the domestic natural gas pressure differential power generation technology with the largest single-unit power, and also filling the gap in the pressure differential power generation project of my country’s gas storage project.
The Suqiao gas storage project is invested by Deyang Energy Group. It adopts the high-pressure, large pressure drop, wide-load differential pressure turbine technology independently developed by Dongfang Steam Turbine. It is also equipped with adjustable stators, which fully matches the “high power-wide load” operation characteristics of the gas storage. The expander speed reaches 15,000 rpm, and the isentropic efficiency can reach 80%, demonstrating Dongfang Steam Turbine’s leading technical strength in the field of natural gas differential pressure power generation.
Dongfang Steam Turbine provides the project with core differential pressure power generation technology – the first domestically developed 3MW differential pressure generator set, and provides users with a full-process comprehensive solution in EPC mode. The successful commissioning of the project has also played an important demonstration role in the utilization of differential pressure energy in natural gas storage and transportation and energy conservation and carbon reduction in the production process.
Forecast of future development space and trend of gas power generation industry market in 2024
Gas-fired power generation is the process of using natural gas or other combustible gases to generate electricity. As a clean and efficient way of generating electricity, gas-fired power generation has received more and more attention and favor, and the current market development status of the gas-fired power generation industry shows a positive trend.
With the transformation of the global energy structure and the improvement of environmental protection requirements, gas-fired power generation, as a clean and efficient way of generating electricity, has received more and more attention and favor, and the current market development status of the gas-fired power generation industry shows a positive trend.
Gas-fired power generation is the process of using natural gas or other combustible gases to generate electricity. A gas turbine is a rotating machine that converts thermal energy into mechanical work, including a compressor (compressors are usually called compressors in gas turbines), equipment for heating working fluids (such as combustion chambers), turbines, control systems, and auxiliary equipment; air is generally used as the working fluid.
A gas turbine power unit is a gas turbine and all the basic equipment necessary to generate useful power (such as electrical energy, mechanical energy, or thermal energy). A simple cycle gas turbine is the gas turbine with the simplest thermodynamic cycle and is currently the most commonly used gas turbine. A single cycle is the simplest thermodynamic cycle of a gas turbine cycle gas turbine. The higher the maximum temperature of the cycle, the higher the efficiency, and vice versa. Generally, the inlet temperature of a gas turbine cycle is the atmospheric temperature, which has a definite value with relatively small changes determined by the earth’s climate conditions. Therefore, the first factor that determines the efficiency is the maximum temperature of the cycle, that is, the inlet temperature of the gas turbine (usually referred to as T3). T3 is usually a characteristic quantity for measuring the performance level of a gas turbine.
Datang Haikou Natural Gas Power Generation Project Unit 2 successfully put into operation
On the evening of May 30, Unit 2 of the Datang Haikou Natural Gas Power Generation Project successfully passed the 168-hour trial operation and was officially put into commercial operation, marking the completion of the first phase of the project and the completion of the two 9F-class (2×487.1MW) gas-steam combined cycle power generation units.
After the “dual machines” are put into operation, Datang Haikou’s natural gas generator sets can achieve an annual power generation of 2.4 billion kWh, an annual output value of 1.4 billion yuan, an annual saving of about 250,000 tons of standard coal, and an annual reduction of more than 1.92 million tons of carbon dioxide emissions. It will meet the growing electricity demand for the construction of Hainan Free Trade Port and Haikou’s headquarters economy during the “14th Five-Year Plan” period.
Fault Analysis and Treatment Measures for Gas Generators in Coal Mines
As a kind of electrical equipment in coal mines, the daily inspection and fault repair of gas generators have become the daily work of coal mine electromechanical equipment maintenance. Taking the fault of gas generator set as the starting point, the symptoms and causes of typical faults such as abnormal cylinder liner water temperature, difficulty in starting, and abnormal exhaust temperature are described in detail, and effective preventive measures for faults are proposed, which has a reference and reference role.
Gas generator is a new type of power generation equipment in recent years. It uses gas and air to mix, compress, ignite, and burn in the cylinder to produce high-temperature and high-pressure gas to drive the reciprocating motion of the piston, and then drives the crankshaft to work through the connecting rod to output electrical energy. This power generation equipment has the advantages of energy saving, environmental protection, low cost, and low pollution. It gradually replaces traditional power generation equipment units and is currently used in many industries such as domestic coal mines.
1 Common faults and causes of gas generator sets
1.1 Failure phenomena of cylinder liners
In gas generator sets, the quality of the working environment of the cylinder liners directly affects whether the engine can operate normally. Therefore, it is very important to ensure the working conditions of the cylinder liners. Improper use will cause the engine’s working performance to decline, causing serious wear, cylinder pulling, cylinder sticking, cavitation and other damage, and even serious accidents.
During the use of the cylinder liner of the gas generator set, the cleanliness of the intake air should be ensured, and the inner diameter size should be measured regularly. It cannot work without the air filter installed; the air filter should also be cleaned regularly to ensure the filtering effect and reduce the wear of the cylinder liner; the cooling of the cylinder liner should also be maintained. When the ambient temperature is low, it should be preheated before starting, and the machine should be kept warm. When the water temperature rises to 40℃ or above, it can be loaded and operated; it must be ensured that it cannot work when the water is cut off or the water temperature is too high to prevent the cylinder from pulling or sticking; overload operation is not allowed; when disassembling and inspecting the cylinder liner, observe the distance between it and the piston. If abnormal or severe wear is found, it should be repaired or replaced in time to avoid leakage, power reduction or severe cylinder pulling and other faults; during the operation of the gas generator set, the ECM control module or the upper computer will report the cylinder liner water temperature alarm signal if there is an abnormal fault; in addition, there are also thermostat faults, circuit faults and other faults.
1.2 Ignition and difficult starting failure
In the magneto of the gas generator, its ignition system mainly includes magneto, low-voltage cable, ignition coil, high-voltage cable, spark plug and other parts. Among them, 12 ignition coils correspond to 12 high-voltage ignition wires and 12 spark plugs. The ignition process is mainly transmitted to the spark plug through the ignition coil and the high-voltage ignition wire, and finally the three electrodes at the top of the spark plug discharge. The magneto ignition system in the gas generator is shown in Figure 1.
The symptom of the difficult starting failure is that the equipment cannot start after the unit is started and powered on. There are many reasons for this failure phenomenon, such as end hole blockage, inability to drive the motor to start the battery voltage (compressed air pneumatic motor, low voltage cannot drive the motor), ignition coil or ignition controller failure, etc.; in addition, if the generator starting speed reaches the ignition speed, but there is still no ignition explosion sound, the indicator light of the ignition controller should be observed. The indicator light status and faults are shown in Table 1.
Research and application of comprehensive utilization of waste heat from flue gas and jacket water of gas generators
In order to eliminate the emission of associated gas and realize the utilization of associated gas, my country’s oil and gas stations, especially remote stations without grid electricity, are increasingly using natural gas for power generation. According to tests, only 33% of the heat of power generation gas is used for power generation, and about 42% of the heat is discharged through high-temperature flue gas. How to efficiently recycle the high-temperature flue gas and jacket water generated by gas generators to meet the requirements of energy saving, safety and environmental protection has become the focus of attention in related fields. The Yongqing Gas Processing Station of the Fourth Oil Production Plant of the North China Oilfield Branch has two 1,200 kW gas generator sets with a power generation capacity of about 800 to 900 kW. The station is provided with heat energy by gas steam boilers to meet the heat needs of production and life. The power is two 1,200 kW natural gas generators of Jichai connected to the grid for power generation. The heat of the generator flue gas and jacket water is not recovered, resulting in large heat losses. The on-site application of flue gas and jacket water waste heat recovery process and nickel-based brazed heat pipe waste heat boiler at Yongqing Station can increase the thermal efficiency of gas to 70%, replacing or reducing the load of gas boilers. The results show that the comprehensive utilization of waste heat recovery of flue gas and jacket water of gas generators reduced gas use by 30×104 m3 in the first quarter of 2022, creating an economic benefit of about 600,000 yuan. Good economic benefits have been achieved.
The Yongqing Gas Processing Station of the Fourth Oil Production Plant of North China Oilfield Branch is mainly responsible for natural gas dehydration and dehydrocarbonization and stable fractionation of natural gas condensate. The station processes 25×10’4~30×10’4 m’3 of natural gas per day and produces 30 t of liquefied gas and stable light hydrocarbons. The station is mainly provided with heat energy by gas steam boilers to meet production and living heat needs. The annual gas consumption is 56×10’4 m’3. The power is two 1,200 kW natural gas generators of Jichai connected to the grid for power generation. The heat of the generator flue gas and jacket water is not recovered, resulting in large heat losses.
1. Steam generation system using high-temperature flue gas
Each 1,200 kW gas generator set in this station has a power generation capacity of about 800~900 kW. According to the test results of domestic manufacturers, only 33% of the heat of the burned gas is used for power generation, and about 42% of the heat is discharged through high-temperature flue gas. In order to make full use of the waste heat, a waste heat utilization system is designed to make full use of the heat of high-temperature flue gas.
1.1 Thermal calculation
The formula for complete combustion of natural gas in air is: CH4 + 2O2 + 8N2→2H2O+CO2+8N2; the formula for incomplete combustion of natural gas in air is: CH4+3O2+12N2→4H2O+2CO2+12N2.
At present, when the 1200 kW natural gas generator set produced by China National Petroleum Corporation Jichai Power Co., Ltd. is in normal operation, the power generation capacity is 900 kW and the exhaust gas temperature is about 580 ℃. When the steam temperature of the high-temperature brazed heat pipe waste heat recovery device is about 152 ℃, the exhaust gas temperature is 200 ℃. When natural gas is completely burned, the volume ratio of natural gas to air is 1:10. In order to make the fuel burn fully, the general mixing ratio of gas to air is 1:12 (calculated based on 1 m’3 generating 3.0 kWh of electricity).
Qe = mΔhsηg
Where: Qe is flue gas waste heat, kJ/h; m is flue gas mass, kg/h; Δhs is flue gas drop, kJ/kg; ηg is efficiency 95%; it is obtained that Qe = 548 kWh, and the heat that can be recovered by the two generator sets is 1 096 kWh.
1.2 Calculation of heat exchange area of waste heat boiler
See formula (1) (2) in the figure
Where: Q is total heat exchange energy, kJ; UA is total heat exchange coefficient, kJ/(℃·m’2); ΔTLM is logarithmic mean temperature difference, ℃; Ft is logarithmic mean temperature difference correction coefficient; ΔT1 is the temperature difference between hot flow outlet and cold flow inlet, ℃; ΔT2 is the temperature difference between hot flow inlet and cold flow outlet, ℃; A = 100 m’2.
2 Flue gas steam system
2.1 Nickel-based brazed heat pipe waste heat boiler
Nickel-based brazed pipe, that is, nickel-chromium alloy is infiltrated into the surface of boiler tube or ND steel (low temperature dew point corrosion resistant steel) to form a dense and smooth coating, so that the welding rate of tube segments and mother tubes is 100%, which effectively expands the heat exchange area and improves the heat exchange coefficient. At the same time, it has good high temperature resistance and corrosion resistance.
2.2 Structural characteristics of nickel-based brazed heat pipe waste heat recovery device
1) Compact structure and large heat exchange area. The heat exchange area of brazed heat pipe per unit length is about seven times that of ordinary light pipe, and the brazed heat pipes are independent. Therefore, compared with the equipment of ordinary light pipe of brazed heat pipe waste heat recovery device with the same heat exchange area, its volume and floor space are reduced several times, and its weight is also reduced to varying degrees.
2) Easy maintenance. Brazed heat pipes are made of a whole seamless steel pipe, which makes them highly pressure-resistant and rarely have quality problems. If a brazed heat pipe bursts by chance, only one end will leak while the other end will be intact, so it will not affect the operation of the equipment without replacement.
3) There is no thermal stress in the pressure-bearing components. When each brazed heat pipe is assembled, there is no forced assembly phenomenon, so no assembly stress will be generated. At the same time, each end is in a free state. In this way, no thermal stress is generated during the operation of the equipment.
4) It can operate efficiently and continuously. According to its heat transfer mechanism and structural characteristics, brazed heat pipe technology has strong anti-scaling, anti-ashing and self-de-scaling and de-ashing capabilities. Its equipment can maintain efficient operation for a long time. The installation of waste heat boiler is shown in Figure 1.
2.3 Waste heat system for flue gas steam generation
The heat of the flue gas is transferred to softened water through the heat pipe section with an enlarged heating area, and the water is heated to saturated steam in the form of natural circulation. The steam space is controlled by the water level controller to increase the pressure of saturated steam, and the signal is transmitted to the feed water pump through the control cabinet. The water level is always kept at a constant value through PID frequency conversion control.
The system consists of a high-temperature flue gas steam generator, a boiler feed water pump (frequency conversion motor), a high-temperature flue gas feed water heater, a softening water tank feed water pump, valve instruments, a PLC control cabinet, and water and steam transmission pipelines. The flue gas waste heat recovery system is shown in Figure 2.
3 Cylinder jacket water hot water system
3.1 Thermal calculation
The jacket water inlet temperature is 67 ℃; the jacket water outlet temperature is 74 ℃; the jacket water circulation water volume is 60 m’3/h; the heat that can be recovered from the jacket water of a single unit is 488 kWh, and the jacket water of two generators recovers a total of 976 kWh of heat.
Fault diagnosis and treatment analysis of Jichai H16V190ZLT4-2 gas generator in single-circuit power supply line
As an important backup power source in the long-distance natural gas pipeline, the safe and reliable operation of the gas generator is directly related to the normal production of the natural gas transmission station when the city power fails. In order to ensure the normal use of the Jichai H16V190ZLT4-2 gas generator set in the single-circuit power supply line, it is necessary to pay attention to the diagnosis and timely elimination of the faults of the generator. Combined with the actual operation experience of the Jichai H16V190ZLT4-2 gas generator in the single-circuit power supply line, the common fault problems of the Jichai H16V190ZLT4-2 gas generator are analyzed, and some preventive measures are proposed.
Due to the single-circuit power supply, some stations of the Xinjiang Oil and Gas Transmission Branch of the Western Pipeline Company of the National Pipeline Network use the Jichai H16V190ZLT4-2 gas generator as a backup power source. As shown in Figure 1, during use, failures such as start-up failure and load shutdown often occur, which seriously affect the normal operation of the station. Combined with the daily maintenance experience of gas generators, the causes of gas generator start-up failure are comprehensively analyzed, and corresponding treatment measures and methods are proposed.
1 Fault phenomenon and cause analysis
1.1 Common fault phenomenon
Using Jichai H16V190ZLT4-2 gas generator as backup power supply, the following fault phenomena often occur during use:
1) The generator cannot reach the drag speed after starting, resulting in start failure;
2) The generator cannot start normally in winter;
3) The overspeed alarm stops when the generator is loaded;
4) The exhaust temperature difference alarm appears after the generator starts.
1.2 Common fault cause analysis
First, the Jichai H16V190ZLT4-2 gas generator cannot reach the drag speed after starting, resulting in start failure. This phenomenon is due to the fact that each generator is equipped with two starting motors. If one motor fails or the starting voltage is low during the start process, the unit speed will not meet the requirements and the start will fail. Secondly, the Jichai H16V190ZLT4-2 gas generator cannot start normally in winter. This is because when the temperature is low in winter, the lubricating oil coolant of the generator cannot be used normally due to the low temperature in winter. In response to this phenomenon, a heater is configured for the generator in the actual production process. However, due to the low power of the heater, the displacement of the circulating pump is small, and the winter temperature in the Gobi Desert is very low, it is very easy to cause the lubricating oil to increase in viscosity and cause the gas generator to fail to start. Then there is the phenomenon that the Jichai H16V190ZLT4-2 gas generator stops when it is loaded [1-2]. The reason for this is that after the gas generator is loaded, due to the intermittent start-up of the large-load equipment in the station, there is a sudden increase and decrease in load, which will bring impact to the gas generator and cause the generator to be unstable when loaded. The last phenomenon is that the exhaust temperature difference alarm often appears after the Jichai H16V190ZLT4-2 gas generator is started. The reasons are many, such as: spark plug carbon deposition and failure to ignite; ignition coil failure; valve clearance problems of the engine cylinder intake and exhaust valves; and thermocouple failure. Among them, valve clearance problems are the most common.
2 Suggestions for solutions to fault phenomena and data analysis
2.1 Solutions to fault phenomena
Combined with specific causes, some solutions are proposed as follows.
① The generator cannot reach the drag speed after starting, resulting in a start failure (it is recommended to increase the starting motor voltage, reduce the starting current, replace in pairs after a fault occurs, etc.)
② The generator cannot start normally in winter (add heating facilities in the generator plant: increase the generator heater power and circulating pump displacement; fully lubricate before starting)
③ The overspeed alarm stops when the generator is loaded (increase the initial stable load when loaded; reasonably set the settings of the station’s ghost facilities to reduce the impact load; adjust the generator speed adjustment gain coefficient)
④ The exhaust temperature difference alarm appears after the generator is started (clean the carbon deposits of the spark plug, perform daily inspections and replacements on the ignition coil, and perform regular daily maintenance on the valve and cylinder head)
2.2 Data analysis of valve clearance and daily maintenance precautions
For the exhaust temperature difference alarm failure that occurs after the Jichai H16V190ZLT4-2 gas generator is started, the valve clearance problem of the cylinder intake valve and exhaust valve is analyzed and studied as follows, as shown in Figure 2. After statistics of all valve sinking data, it was found that the wear sinking of the exhaust valve was close to 0mm, while the wear sinking of the intake valve was mainly concentrated between 2 and 4mm. The average wear sinking of the upper intake valve was 2.69mm, and the average wear sinking of the lower intake valve was 2.43mm. Therefore, the wear sinking of the intake valve was studied and analyzed in detail.
Performance test and analysis of 90 kW water-to-air cooled gas generator
The development of small-scale gas-fired distributed energy systems can effectively reduce the initial investment of equipment and expand the application occasions. Taking a modified domestic 90 kW water-to-air cooled gas generator as the research object, a gas generator test platform and a selective catalytic reduction technology flue gas denitrification test platform were built to study the changes in parameters such as power generation efficiency, steady-state voltage, current frequency and flue gas denitrification efficiency under different load rates. The research results show that the power generation efficiency of the generator using water-to-air cooling can reach 36.12%, which is about 3 percentage points higher than the power generation efficiency of conventional gas generators of the same scale. The fitting equation between power generation efficiency and load rate is obtained, and the rated voltage and current frequency of the gas generator output meet the power supply quality standards. After denitrification treatment, the NO* emission mass concentration in the flue gas is stabilized at 41 mg/m3, and the denitrification efficiency exceeds 95%.
Gas generators are devices that allow mixed gas and air to enter cylinders, ignite and burn to generate power, and drive pistons to generate electricity. They have a high power generation efficiency of 30% to 40%, high equipment integration, quick installation, low cost per kilowatt, and strong adjustment capability. They are usually used in gas-fired distributed cogeneration systems or as backup power sources.
The power generation of gas-fired generator sets that generally match large-scale gas-fired trigeneration systems is above the megawatt level, and generally adopts air-to-air intercooling for heat dissipation. However, large-scale gas-fired distributed energy systems require large initial investments and limited usage scenarios. Therefore, it is of great significance to develop and use flexible and small gas-fired distributed energy systems. At present, there are few reports on the performance of small gas-fired generator sets and their performance improvement potential in domestic and foreign literature. This paper aims to explore the power generation performance of gas-fired generator sets suitable for small distributed energy systems, and to reveal the law of performance improvement by transforming the intercooling cooling method of the unit into water-to-air intercooling. In addition, the nitrogen oxide (N0x) content in the exhaust gas of gas-fired generator sets is high. In order to meet the increasingly stringent environmental emission requirements, the denitrification of gas-fired generator flue gas was tested.
1 Introduction to water-air cooled gas generator
1.1 Main technical parameters
The gas generator set consists of a body, two major mechanisms (crank-connecting rod mechanism, valve mechanism) and six major systems (supply system, lubrication system, cooling system, ignition system, starting system, electronic speed control system), mainly including body, crankshaft, shock absorber, piston, connecting rod, cylinder liner, cylinder head, ignition system, lubrication system, cooling system and exhaust system. The appearance of a domestic 90 kW gas generator used in the test in this article is shown in Figure 1.
The gas generator type is three-phase four-wire, consisting of 6 cylinders, and the working cycle of each cylinder consists of four strokes, namely intake stroke, compression stroke, power stroke and exhaust stroke. The intake method of the gas generator is supercharged intercooling, and the cooling method is water-cooled forced circulation.
The gas generator adopts water-air intercooling, that is, the gas and air are mixed and pressurized through the mixer, and then enter the cylinder for compression after heat exchange and cooling in the intercooler (Figure 1). The cylinder temperature is controlled by the cylinder jacket water circulation cooling system. The gas used in this gas generator is natural gas, and its main technical parameters are displacement 6.75 L, rated output power 90 kW, rated voltage 400 V, speed 1 500 r/min, current frequency 50 Hz, minimum fuel consumption rate not more than 210 g/(kW・h), power coefficient 0.8, and noise not more than 102 dB.
1.2 Intake and exhaust data
The gas inlet gauge pressure of the gas generator is 2~4kPa, the flue gas outlet back pressure is 7.5 kPa, the maximum intake negative pressure is 6.7 kPa, the air intake mass flow rate is 530.70 kg/h, the gas intake mass flow rate is 19.57 kg/h, the gas test calorific value is 38.50 MJ/m3 (under standard conditions), the exhaust mass flow rate is 550.27 kg/h, and the exhaust temperature is 543 °C. The mixed volume ratio of air and gas is 13, which is mainly controlled by the mixer. The gas air-fuel ratio has a significant impact on exhaust emissions, power and economy of the generator. In order to achieve the best exhaust emission quality, an oxygen concentration sensor is installed in the generator exhaust pipe, and closed-loop control of the fuel is realized to control the gas air-fuel ratio of the generator in the lean combustion area, so that the gas is fully burned, and the fuel consumption rate is lower and the emission standard is higher.
The maximum emission of N0* in the flue gas of the gas generator is 6 g/(kW-h), which is equivalent to 1 300 mg/m3 (standard state). According to the provisions of Beijing Local Standard DB 11/1056-2013 <Emission Standards for Air Pollutants for Stationary Internal Combustion Engines> (1), the maximum allowable emission mass concentration of nitrogen oxides for internal combustion engines fueled by natural gas and artificial coal gas is 75 mg/m30. Therefore, the emission of nitrogen oxides in the flue gas of the gas generator does not meet the emission requirements and needs further treatment. Based on the exhaust temperature of the gas generator, it is appropriate to use selective catalytic reduction technology (SCR) for denitrification.
1.3 Thermal balance test data
The designed gas generator water inlet/outlet pressure is 13/37.5 kPa, the cooling cylinder jacket water volume flow is 10.8 m3/h, the cylinder jacket water inlet/outlet gas generator temperature is 80/85 °C, and the intercooler front/rear temperature is 45/40 °C. The total power input of the gas generator is 280.44 kW, of which the intercooler water takes away 10.2 kW of heat flow, and the flue gas and cylinder jacket water take away 140.8 kW of heat flow. Therefore, it is necessary to utilize the energy of flue gas and cylinder jacket water through efficient waste heat recovery technology. Waste heat absorption refrigeration or production of domestic hot water is an effective way to utilize waste heat of distributed small gas engines. In addition to power generation, the remaining heat flow is dissipated through surface radiation, about 14.02 kW.
2.90 kW gas generator performance test platform
In order to test the performance of the gas generator under variable load, a gas generator performance test platform was built, as shown in Figure 2.
Natural gas enters the gas generator through solenoid valve VI and gas flowmeter F21, burns and generates electricity, and then is discharged. The generator’s outlet jacket water is cooled by the jacket water heat exchanger, flowmeter F1, and water pump P3, and then returns to the gas generator. The intercooler water is cooled by flowmeter F2, intercooler water heat exchanger, and water pump P4, and then returns to the gas generator. The cooling of the intercooler water and jacket water is achieved by the cooling water heat exchange of the cooling tower. At the output end of the generator, a load box with adjustable load power is connected. The voltage, current, and frequency comprehensive test bench is used to measure the current, voltage, frequency, and electric power, and record the gas flow of the gas generator under different loads. The basic conditions for the performance test are: gas generator speed 1500 r/min, ambient temperature about 25 °C, atmospheric pressure 101.3 kPa, natural gas inlet pressure 1.5 kPa, natural gas intake temperature 18 °C, cylinder jacket water circulation volume flow 10.8 m3/h, intercooler water circulation volume flow 3 m3/ho. Based on the natural gas composition data shown in Table 1, it can be seen that the low calorific value of natural gas under standard conditions is 33.41 MJ/m’3.
The total input heat flow Φ of natural gas is: see formula (1) in the figure
Where 4 is the total input heat flow, kW; gp is the natural gas volume flow under standard conditions, m’3/h; Q is the low calorific value of natural gas under standard conditions, MJ/m’3.
The power generation efficiency ηe is the ratio of the output power Pe to the total input heat flow of natural gas: see formula (2) in the figure
3 Flue gas denitrification test process
Urea is used as the denitrification reducing agent for flue gas SCR denitrification, and its test process is shown in Figure 3.
The catalyst in the SCR reactor is a honeycomb high-temperature iron-based molecular sieve catalyst with a large specific surface area, and the operating temperature of the reactor is 450~550 °C. The urea solution and compressed air are mixed and sprayed into the high-temperature flue through the injector, first decomposing to produce NH3. Under the action of the catalyst, NH3 selectively reacts with NOx in the flue gas to produce N2 and NOx, which are then discharged into the atmosphere. The main reaction formula for flue gas denitrification is as follows:
C0(NH2)2+H20➡2NH3+C02
4N0+4NH3+02➡4N2+6H20
2N02+4NH3+02➡3N2+6H20