Black Seal TC Practice Exam

The three types of draft commonly used in power plants are natural, forced, and induced.

Natural draft relies on the natural buoyancy of hot gases, which rise and create a pressure difference that allows air to flow into the combustion area. This method is often seen in systems where the height of the stack or chimney promotes efficient airflow based on temperature differences without any mechanical assistance.

Forced draft involves the use of fans to push air into the combustion area, increasing the amount of oxygen available for combustion and improving efficiency. This method allows for better control over the airflow compared to natural draft.

Induced draft also uses fans, but they are placed at the outlet of the combustion chamber or flue. This setup helps to create a vacuum effect that draws combustion gases out of the boiler or furnace, assisting in the removal of exhaust gases and contributing to better efficiency and safety of the overall system.

Each of these draft types has its specific applications and efficiencies, making them tailored to various operational needs within power plants.