Where is the chemical injection line typically located in a boiler system?

The correct answer is that the chemical injection line is typically located near the internal feed pipe in a boiler system. This is because the chemical injection is designed to treat the boiler water to prevent issues such as scaling and corrosion. By placing the injection line close to the feed water line, the chemicals can be evenly mixed with the water before it enters the boiler. This ensures that the appropriate dosages are delivered consistently, maximizing the effectiveness of the chemicals in maintaining water quality.

Options involving the steam dome, flue gas outlet, and water level gauge do not serve the purpose of chemical treatment. The steam dome is primarily associated with the separation of steam from the water in the boiler, while the flue gas outlet pertains to the exhaust of combustion gases, and the water level gauge is used for monitoring water levels, not for injection of chemicals. Therefore, placing the injection line near the feed pipe optimally supports the water treatment process essential for safe and efficient boiler operation.