What is the purpose of a refractory lining in a boiler?

The purpose of a refractory lining in a boiler is to insulate and protect the boiler from high-temperature combustion gases. This lining is made of materials that can withstand extreme temperatures and corrosive conditions, which helps maintain the integrity of the boiler structure. By insulating the interior surfaces, the refractory lining minimizes heat loss, ensuring that the heat generated during combustion is effectively retained for the steam generation process. This not only enhances safety by preventing overheating of critical components but also contributes to the overall efficiency of the boiler operation.

The other options don't address the specific role of the refractory lining correctly. For instance, while temperature regulation of feed water and fuel efficiency are important factors in boiler operation, they are not directly linked to the function of the refractory material. Preventing water leaks is also a vital aspect of boiler design and operation, but it pertains more to the construction and sealing of the boiler rather than the protective function of the refractory lining itself.