During low operational loads, an exhaust gas bypass is used to prevent what issue within the waste heat boiler?

The use of an exhaust gas bypass during low operational loads primarily addresses the issue of moisture condensation within the waste heat boiler. When the operational load is low, the temperatures within the boiler may not be adequately maintained, leading to a drop in gas temperature. If the gas is not hot enough, moisture in the exhaust can condense, which is detrimental as it can lead to corrosion and other operational problems within the boiler system.

By allowing exhaust gases to bypass the heat recovery process at low loads, the system can ensure that the gases remain above their dew point, thereby preventing moisture from condensing. This effectively protects the components of the waste heat boiler and maintains its efficiency and longevity.