In various fields such as industrial production, construction, and emergency backup power supply, diesel generators play an indispensable role. A stable and efficient fuel supply system is a key factor in ensuring the reliable operation of diesel generators. This article will provide a detailed discussion on the installation points, precautions, and maintenance suggestions for the daily fuel tank, main storage tank, and related pipelines in the diesel generator fuel system. It aims to offer a comprehensive and practical reference for relevant practitioners.
The installation of the daily fuel tank is crucial in the fuel system of a diesel generator. Here are the key points for installing a daily fuel tank.
The daily fuel tank plays a pivotal role in the fuel system of a diesel generator, and its installation location is of utmost importance. First and foremost, the daily fuel tank should be positioned as close to the generator set as possible. The purpose of this is to maintain the minimum input resistance for the fuel transfer pump of the generator set. When the distance between the tank and the generator set is too great, the fuel will experience increased energy consumption during transfer due to pipeline resistance. This may even lead to insufficient fuel supply, affecting the normal operation of the generator set. The auxiliary fuel pump is responsible for transferring fuel from the main storage tank to the daily fuel tank, while the generator set's fuel pump conveys fuel from the daily fuel tank to the generator set's injection system and returns any excess fuel back to the daily fuel tank, forming a circulation.
After fuel is pumped into the daily fuel tank, it needs to be allowed to settle for more than 48 hours. This is because fuel inevitably contains some impurities and moisture during storage and transportation. Through sedimentation, these impurities and moisture can settle to the bottom of the tank, preventing them from being drawn into the diesel generator and thereby reducing the risk of engine failure. The minimum fuel level in the daily fuel tank should not be lower than 1 meter from the inlet of the fuel transfer pump. This ensures that the fuel transfer pump can smoothly convey fuel to the generator set. Additionally, the fuel supply pipe to the diesel generator should be at least about 100 millimeters above the bottom of the tank. This effectively prevents the intake of settled contaminants and moisture into the diesel generator, ensuring the cleanliness of the fuel.
When installing the daily fuel tank, it is also important to position it away from heat and vibration sources of the diesel generator, such as exhaust pipes and electrical equipment. This is because when diesel fuel reaches a temperature of 65°C, vaporization occurs, which can prevent the diesel generator from functioning properly. Vibration, on the other hand, can stir up sediment, causing blockages in the fuel system of the diesel generator and wear on the generator set, severely affecting the service life and operational stability of the equipment.
For ease of operation and monitoring, a manual fuel pump and a fuel gauge should also be installed on the daily fuel tank. The fuel gauge is used to measure the amount of diesel stored in the fuel tank. With it, one can visually understand the remaining fuel level in the tank and promptly carry out refueling operations to avoid generator set shutdowns due to insufficient fuel.
As the link connecting various components, the installation quality of fuel transfer pipelines directly affects the sealing and safety of the fuel system. Here are the key standards for installing fuel transfer pipelines.
The installation quality of fuel transfer pipelines, which serve as the link connecting various components, directly affects the sealing and safety of the fuel system. Fuel transfer pipes are generally made of black iron steel. This material has good corrosion resistance and mechanical strength, enabling it to withstand the pressure and wear during fuel transfer. However, for small fuel pipes with a diameter of less than 13 millimeters, copper pipes can also be used as a substitute. Attention must be paid to the connection process of copper pipes to ensure the sealing of the joints.
When installing fuel transfer pipelines, the key is to ensure that diesel fuel does not leak, whether the system is in operation or at rest. Diesel leakage not only causes fuel waste but also allows air to enter the fuel system, making the diesel generator run unstably and affecting its output power. The installation of flexible hoses should use high-quality clamps, and iron wire binding should never be used. This is because iron wire can easily loosen or cut through the fuel hose over time, leading to fuel leakage accidents.
In addition, fuel pipes should be installed away from heat sources, such as exhaust manifolds and turbochargers, to prevent fuel overheating. The maximum temperature of fuel entering the engine fuel nozzle should not exceed 66°C. For every 6°C increase above this temperature, the power will be reduced by 1%. Valves should not be used in the fuel return line to avoid damaging the fuel filter. The return line should enter the tank from the top to ensure smooth fuel return and prevent fuel accumulation in the return line.
To isolate vibrations, flexible connections should be used between the engine, fuel pipes, and fuel tanks. The diameter of the fuel inlet and return pipes should not be smaller than the corresponding interfaces on the engine to ensure smooth fuel transfer and return. Moreover, valves and fittings can be made of cast iron or bronze, but brass should be avoided. This is because brass contains zinc, which can easily react with sulfur compounds in fuel, posing a risk of blockage.
The main storage tank is the "backbone" of the diesel generator fuel system, and its installation location and capacity determination have a profound impact on the stable operation of the entire fuel system.
When installing the main storage tank, it should be positioned as close to the generator set as possible. This can shorten the length of the fuel transfer pipeline, reduce pipeline resistance, and lower the risk of fuel leakage. If building regulations and fire safety codes permit, the main storage tank can be installed next to the generator, within the generator base, or in an adjacent room. This not only facilitates management and maintenance but also improves the efficiency of fuel supply.
To quickly start the generator set, the ideal fuel level in the main storage tank should be at the same height as the inlet of the fuel transfer pump, but the maximum fuel surface should not be higher than 2.5 meters above the generator set base. This is because an excessively high fuel level may cause cavitation during fuel transfer, affecting the stability of fuel supply. The diameter of the fuel supply pipe from the main storage tank is 25 - 35 millimeters, and the return pipe has the same size. However, the height of the fuel line to the tank must be kept below 2.5 meters. The tank cover must be equipped with a pressure balancing hole that communicates with the atmosphere, and an air filter felt pad should be installed on the inside of the cover to prevent dust and impurities from entering the tank. A filter screen is installed inside the fuel inlet to provide preliminary filtration of the fuel entering the tank. A drain plug is installed at the bottom of the tank to regularly discharge settled contaminants or moisture, maintaining the cleanliness of the fuel in the tank.
The determination of the main storage tank's capacity needs to take into account the generator set's rated load, speed, and expected operating time. Generally, the tank should be large enough, and its size should be determined based on the hourly fuel consumption of the generator set's rated load and speed, multiplied by 8, to avoid refueling during operation. An empirical rule for diesel generator fuel consumption is: multiply the kW rated value by 0.27 to obtain the fuel consumption (in liters). For example, a 100kW generator set operating at full load will consume approximately 30L of fuel per hour. When designing the tank capacity, the standard should be to ensure the minimum fuel supply for continuous operation. Sometimes the generator set may need to run for several hours, days, or even weeks, so the tank capacity should be reasonably determined according to the actual usage.
A high-quality fuel system, in addition to strictly following installation standards, should not neglect maintenance work. Here are some maintenance suggestions.
Regularly inspect the sealing of the fuel tanks and pipelines, and promptly identify and repair any leakage points to prevent fuel waste and safety hazards caused by fuel leakage.
Regularly clean the sediment and water in the fuel tanks to maintain the cleanliness of the fuel. It is generally recommended to carry out a thorough cleaning every quarter, and at the same time, check whether the anti-corrosion layer on the inner wall of the tank is intact. If any damage is found, it should be repaired in a timely manner.
Regularly inspect the fuel filter elements and replace them according to usage conditions to ensure that fuel can pass through the filter smoothly and avoid insufficient fuel supply due to clogged filter elements.
Check the operating conditions of fuel transfer pumps, circulation pumps, and other equipment, paying attention to any abnormal noises or vibrations. Regularly maintain these devices, replace worn parts, and ensure their normal operation.
Check whether the electrical equipment such as temperature sensors and circulation control boxes are working properly to ensure that the fuel temperature control system can accurately feedback and control the fuel temperature, ensuring that the engine operates within the optimal temperature range.
Regularly conduct pressure tests on the entire fuel system to check the pressure changes under different operating conditions, promptly identify potential fault risks, and take measures to deal with them in advance.
In summary, the installation and maintenance of diesel generator fuel systems is a systematic project that requires strict adherence to relevant standards and requirements. Only by ensuring the rational installation, correct use, and regular maintenance of daily fuel tanks, main storage tanks, and pipelines can the stable operation of the diesel generator fuel system be guaranteed. This, in turn, provides a solid foundation for the reliable operation of diesel generators. It is hoped that the introduction in this article will be of help to relevant practitioners. In actual work, it is necessary to flexibly apply the knowledge according to specific situations, continuously summarize experience, improve technical levels, and provide safer and more efficient energy security for fields such as industrial production and emergency backup power supply.
