Boiler, How it works?

Summary

This video explains the operation and construction of a typical thermal power plant boiler, focusing on the process of converting coal's chemical energy into high-temperature steam. It covers the function of water tube boilers, the role of various heat exchangers like economizers, superheaters, and reheaters, and the thermodynamics behind power plant efficiency. The video also addresses a common misconception about boiler pressure, clarifying that in practice, there is only a small pressure drop across the system due to friction and other irregularities. Overall, the video provides valuable insights into the technical aspects of power plant boilers.

Takeaways

• 😀 The boiler is the most critical component of a thermal power plant.
• 🔥 A boiler's primary function is to convert energy from coal into high-temperature steam.
• 💧 Water tube boilers are commonly used in large power plants for high-pressure applications.
• 🔥 Burners in the boiler convert chemical energy from pulverized coal into thermal energy.
• 🌡️ The economizer absorbs energy from the flue gas to increase the temperature of the water.
• 💦 The steam drum separates water droplets from the steam to ensure pure and saturated steam.
• ⚙️ According to the second law of thermodynamics, higher heat source temperatures improve efficiency.
• 🌡️ Steam temperature is limited to a maximum of 600°C due to turbine blade material constraints.
• ♨️ Superheating steam increases power plant efficiency by raising the steam temperature to its maximum limit.
• 🔄 Reheating steam after the first turbine stage increases both efficiency and plant capacity.
• ❓ A common misconception is that pressure rises in the boiler as temperature increases. In reality, the pressure remains almost constant due to the open-flowing nature of the water inside the boiler.

Q & A

What is the primary function of a boiler in a thermal power plant?

The primary function of a boiler in a thermal power plant is to convert the energy contained in coal into high-temperature steam, which is essential for generating electricity.

What type of boiler is typically used in large power plants?

Large power plants typically use a water tube boiler, where water flows through the tubes and fire surrounds it, making it suitable for high-pressure applications.

How does a burner in a boiler convert energy?

A burner in the boiler converts the chemical energy in pulverized coal into thermal energy, which heats the water inside the boiler.

What is the purpose of the economizer in a boiler?

The economizer absorbs energy from the flue gas to raise the temperature of the water supplied by the feed water pump, improving the overall energy efficiency of the system.

What is the function of the steam drum in a boiler?

The steam drum's main function is to separate water droplets from the steam produced, ensuring that the steam leaving the drum is pure and saturated.

Why is high steam temperature important in a thermal power plant?

According to the second law of thermodynamics, the higher the temperature of the heat source, the more efficient the cycle. Therefore, increasing the steam temperature results in a more efficient power plant.

What is the limitation regarding steam temperature in a thermal power plant?

The steam turbine blade material cannot withstand temperatures greater than 600°C, which limits the maximum temperature that can be achieved in the steam cycle.

What is the role of the superheater in a boiler?

The superheater increases the temperature of the steam beyond the saturation point, ensuring that the steam reaches the maximum allowable temperature for efficient turbine operation.

What is the purpose of reheating in a power plant?

Reheating is used to increase the power plant's efficiency and capacity. After the first turbine stage, steam is bypassed and reheated to improve the overall performance of the cycle.

What is a common misconception about pressure in a boiler?

A common misconception is that the pressure increases across the boiler. In reality, the water in a boiler is part of an open-flowing system, and as it turns into steam, the pressure remains largely constant, with only a small drop due to friction and irregularities.