News

1. Principles of Boiler Operation

Industrial boilers (steam boilers) are widely used to generate steam and heat for production activities in various industries such as Food & Beverage, Paper, Chemicals, Textiles and Dyeing, Animal Feed, and more. High-pressure steam from boilers is also used in the energy sector when combined with turbines to generate electricity for daily life.

Boiler operation is based on converting energy from fuel combustion or electricity into heat, which then boils water to produce saturated steam in a pressurized environment. Depending on the design, fuel supplied to industrial boilers can vary in form: liquid (oil), gas (natural gas), solid (coal/biomass/waste, etc.).

Industrial boilers are typically constructed by welding together thick steel plates, allowing them to withstand extremely high pressures, ranging from a few Barg to hundreds of Barg, depending on the initial design capacity. This is significantly higher than the pressures handled by conventional pressure vessels.

There are many different types of boilers depending on the field of use. The classification of boilers is based on design, combustion methods (type of fuel and how it is burned), and technology used. Common types include chain grate boilers, fluidized bed boilers, water tube boilers, fire tube boilers, pulverized coal boilers, and biomass boilers.

2. Causes of Boiler Explosions

Currently, boilers are widely used in industrial production. However, operating a boiler safely and efficiently is not simple. Many incidents have occurred due to improper boiler operation and management, leading to severe damage to both human life and property. Therefore, understanding the causes of boiler explosions is essential to ensure safety and minimize the risk of such incidents.

2.1 Water Depletion

Water acts as an insulating layer protecting the metal walls of the boiler from high temperatures during operation. When the water level drops too low, metal structures can come into direct contact with extremely high temperatures, causing them to melt and deform. Additionally, this situation can cause cracks or loosen steel tubes, leading to water leakage.

Water depletion is particularly dangerous because it allows the boiler body to overheat and potentially explode. Maintaining an adequate water level in the boiler is crucial for safe operation.

Causes of water depletion include:

• Malfunctioning feed water pumps or water level control devices prevent the boiler from receiving enough water.
• Insufficient water in the feed water tank, not enough to supply the boiler.
• Lack of attention during boiler monitoring, resulting in delayed water replenishment when the tank level drops.

To prevent this, install monitoring devices such as water level sensors and automatic cut-off systems to track the water level in the boiler. Regular and thorough maintenance, including checking and cleaning critical parts like pumps, valves, and water level sensors, is also necessary.

2.2 Overpressure

Pressure's primary role is to generate energy, allowing steam to move and perform processes that generate energy, supplying other equipment in the system. Additionally, pressure is crucial for maintaining system stability. Pressure control ensures the boiler operates efficiently without facing issues that could lead to explosions.

Overpressure occurs when the pressure in the boiler exceeds the design limit, significantly increasing the risk of explosion. Causes of overpressure include:

• Malfunctioning safety valve: The safety valve is responsible for releasing steam when the pressure exceeds the set limit. If it fails, steam cannot escape, causing pressure to rise uncontrollably, potentially leading to pipe expansion, cracking, or welding seam leaks, which can cause explosions.
• Rapid pressure increase: Excessive fuel supply increases combustion intensity, rapidly generating steam and causing uncontrolled pressure rise, leading to a boiler explosion.
• Faulty water level warning devices: Problems with water level warning devices affect the accuracy of signal transmission to the control system, potentially leading to continuous water pumping into the boiler when pressure is already too high, causing an explosion.

To prevent overpressure, use pressure-reducing valves to lower outlet pressure when it exceeds safety limits. Regularly inspect details like safety valves, pressure-reducing valves, and pressure control devices to ensure proper functioning. Additionally, install sensors to monitor boiler pressure, providing early warnings of sudden pressure increases to limit explosion risk.

2.3 Over-thermal

Thermal plays a central role in boiler operation. When fuel is burned, the generated thermal is the key factor in converting water into steam or boiling water. Over-thermal occurs when the internal temperature of the boiler exceeds safety limits.

Causes of over-thermal include:

• Overheated superheater (for thermal power plants, cogeneration plants): Common causes include local flue gas flow deviation, leading to some tubes being overheated, resulting in overheating and explosion.
• Scaling on tubes: Poor water treatment or contaminated feed water causes corrosion and scale formation on boiler shell materials. Scale accumulation on boiler shells or tubes reduces heat transfer, increasing tube wall temperature.
• Excessive heating of tube banks: Poor combustion control in the furnace can cause tube banks to overheat, softening boiler shell material, causing deformation, reducing pressure resistance, and leading to boiler explosion.
• Thermal shock: Irregular water addition causes boiler water depletion, drying out steam-generating tube banks. Sudden cold water addition causes thermal shock, damaging tubes and potentially causing explosions.

Prevention measures include:

• Ensuring quality feed water and boiler water to reduce internal tube corrosion and scaling.
• Preventing water circulation issues and avoiding prolonged low-load boiler operation.
• Preventing external tube damage and maintaining proper combustion control in the furnace.

2.4 Calculation Errors

Errors in calculating boiler size, capacity, and pressure resistance during initial design can lead to overheating and uncontrolled pressure during operation, posing a high explosion risk.

Other issues include incorrect fuel amount calculations or selecting unsuitable fuel types, affecting combustion. Unburned fuel can accumulate at high concentrations, and once ignited, it burns rapidly, causing explosions. Incomplete combustion due to insufficient air supply can cause excess fuel mixture, indicated by black smoke at the boiler tail.

Do not add air to a combustion chamber with black smoke, as it may create an explosive mixture. Instead, stop boiler operation for cleaning and find corrective measures.

3. Why Choose Thuan Hai for Boiler Operation?

To ensure efficient, stable boiler operation, and optimize fuel and labor costs, factories, and production facilities should choose reputable, professional boiler operation service providers. The operator must be well-trained, experienced, and skilled in handling any arising situations.

As an ESCO, Thuan Hai proudly specializes in investing, installing, and providing professional boiler operation services for various industries. Here are reasons to trust Thuan Hai as your professional boiler operation partner:

• Comprehensive solutions: Designing and providing energy solutions tailored to each production sector, meeting factory production needs. Evaluating and advising on boiler system upgrades to increase productivity and reduce operational risks. Managing ash, slag, and waste according to regulations, ensuring environmental safety.
• Fuel autonomy: Providing diverse, stable fuel sources. Pioneering the use of biomass and industrial waste as boiler fuel.
• Technological expertise: Continuously updating, improving, and applying advanced global technologies like fluidized bed boilers, chain grate boilers, flue gas treatment systems, cogeneration systems, and more. Monitoring operations 24/7 through the PLC-SCADA central control system, delivering superior efficiency.
• High efficiency: Professional operation techniques, committed to providing sufficient steam-heat-electricity energy for factory production.
• Cost optimization: Implementing 100% automated operation, reducing labor costs. Measuring and calculating reasonable fuel supply to avoid energy waste and loss.
• Specialized team: Experienced technical team with high expertise, dedicated work attitude, trained in boiler operation with professional certificates.