CEM Boiler and Steam Systems 3

Question 1

A flash steam recovery system on a high-pressure condensate line generates flash steam for use at lower pressure. What thermodynamic principle governs this?

Accepted Answer

Throttling of saturated liquid causes partial vaporization as pressure drops, releasing flash steam

Answer

When high-pressure condensate is throttled to lower pressure, some liquid flashes to steam because enthalpy is conserved and saturation temperature drops.

Question 2

Which blowdown strategy is most energy-efficient for controlling boiler water Total Dissolved Solids (TDS)?

Accepted Answer

Continuous blowdown with heat recovery using a blowdown heat exchanger

Answer

Continuous blowdown with a heat exchanger recovers thermal energy from the blowdown stream, minimizing both water and heat losses.

Question 3

What does the term 'boiler horsepower' (BHP) represent?

Accepted Answer

The evaporation of 34.5 lb/hr of water at 212°F, equivalent to approximately 33,475 BTU/hr

Answer

One boiler horsepower equals the evaporation of 34.5 lb/hr of feedwater at 212°F, a traditional unit equal to about 33,475 BTU/hr.

Question 4

In a steam system, what is the primary function of a pressure-reducing valve (PRV)?

Accepted Answer

To step down steam pressure to match lower-pressure distribution or end-use requirements

Answer

A PRV reduces high-pressure steam to a lower set-point pressure suitable for specific process or building heating loads.

Question 5

Which factor most directly determines the 'M' factor (fuel-to-steam efficiency) used in boiler performance assessment?

Accepted Answer

Ratio of useful heat absorbed by steam to the heat input from fuel combustion

Answer

Fuel-to-steam efficiency measures how much of the fuel's heat content is transferred into the steam, accounting for stack losses, radiation, and blowdown.

(CEM) Certified Emergency Manager Practice Test

(CEM) Certified Emergency Manager Practice Test

CEM Boiler and Steam Systems 3