Carryover in a boiler system is the entrainment of what into the steam, and what factors contribute?

• A. The entrainment of boiler water solids or treatment chemicals into the steam; caused by high boiler water solids, excessive steam rate, or improper drum level.
• B. The entrainment of air into steam; caused by leaks.
• C. The entrapment of fuel into steam; caused by poor combustion.
• D. The entrainment of steam condensate; caused by low boiler pressure.

Answer: (A)

Carryover is the entrainment of boiler water components into the steam stream. This means solids from the water and any treatment chemicals can be carried along with the steam, rather than staying in the boiler water.

The best answer describes that solids or treatment chemicals are carried into the steam, and it explains the typical causes: when boiler water solids become high (too concentrated water or poor water treatment), when the steam rate is excessive (high steam velocity shears water droplets into the steam), and when the drum level is improper (water may rise into the steam space and be carried with the steam). These factors together lead to droplets and dissolved materials being carried out of the boiler with the steam, which can cause deposits, foaming, and damage downstream.

Air entering the steam due to leaks, fuel entering the steam due to poor combustion, or condensate being carried because the pressure is low describe other issues that aren’t carryover in the same sense.