Minnesota Boiler License Practice Exam

When pressure increases on steam from a given amount of water, what happens to its temperature?

1. Increases

2. Decreases

3. Remains the same

4. Fluctuates

The correct answer is: Increases

When pressure increases on steam generated from a specific volume of water, its temperature also increases. This relationship is governed by the principles of thermodynamics, specifically the behavior of substances in a state of equilibrium. As steam is heated and pressure is applied, the kinetic energy of the water molecules increases, which subsequently raises the temperature of the steam. This increase in temperature occurs because the boiling point of water rises under higher pressure. For instance, at sea level, the boiling point of water is 212°F (100°C), but as pressure increases, the boiling point also rises. This means that steam can exist at higher temperatures without converting back to water. The understanding of this principle is crucial for operating boilers securely. When managing a steam system, it is important to know that maintaining or adjusting pressure will also affect temperature, which directly impacts steam quality and efficiency of the process.