How does heat recovery affect boiler efficiency?

• A. It adds thermal energy back into the system, improving efficiency.
• B. It increases fuel consumption.
• C. It decreases steam quality.
• D. It has no impact.

Answer: (A)

Heat recovery uses waste heat from the boiler’s exhaust to preheat incoming feedwater or other streams, putting thermal energy back into the system. By preheating water before it enters the boiler, the amount of energy needed from fuel to achieve the same steam output is reduced. That lower fuel input while maintaining the same steam output increases the boiler’s energy efficiency.

In practice, devices like economizers or feedwater heaters capture that heat and improve the overall energy balance, so the system makes better use of the energy that’s already been produced. This is why heat recovery is associated with improved efficiency.

The other statements don’t fit. It does not increase fuel consumption; it reduces the required fuel to produce the same steam. It does not inherently decrease steam quality; in fact, keeping feedwater preheated can help maintain steady steam quality. And it certainly has an impact, since reclaiming waste heat changes the energy balance and lowers fuel use.