Why might a pressurized furnace be undesirable for large boilers?

A pressurized furnace can be undesirable for large boilers primarily because it has the potential to leak flue gases. In a pressurized system, combustion gases are contained under higher pressure, which could lead to unintentional breaches if there are any flaws or weaknesses in the system design, such as pipe joints or seals. If a leak occurs, hazardous flue gases can escape into the environment, posing safety risks to personnel and potentially leading to non-compliance with environmental regulations.

This concern over the integrity of the pressurized system is significant in industrial settings, where large boilers are often critical for various processes. Being vigilant about potential leaks is paramount to ensuring safety and proper operation.

In considering the other aspects, issues such as excessive energy requirements, operation at high pressures, and airflow restriction can be relevant, but they do not specifically highlight the immediate dangers associated with gas leaks as a primary concern. These factors can certainly impact efficiency or operational viability, but the risk of leaking flue gases addresses a more critical safety issue.