Boiler Operation and Safety Quiz

A fire tube boiler is operated beyond its safe pressure rating. Which is the most serious consequence?

• Localized overheating of the furnace shell

• Accelerated corrosion on the water side

• Catastrophic tube rupture due to design pressure limits

• Premature wear of safety valves

Water tube boilers are more suitable for power plants because they:

• Have larger water content, reducing fluctuations

• Minimize scale formation inside the tubes

• Can withstand higher pressures due to water circulating inside tubes

• Eliminate the need for economizers

Repeated high-pressure cycling in cast iron boilers primarily results in:

• Reduced slag deposits

• Improved thermal conductivity

• Cracking and brittle failure under cyclic loading

• Enhanced corrosion resistance

The efficiency contribution of an exhaust gas economizer is best explained as:

• Increasing steam pressure by additional superheating

• Recovering residual flue gas heat to preheat feedwater

• Maintaining furnace flame stability

• Controlling combustion air temperature only

A sudden pressure rise with constant load indicates:

• Excessive economizer heating

• Adequate firing rate but no steam demand

• Blocked steam outlet or defective pressure control

• Improper atomization of fuel

In ignition systems, oil burners face more risk than gas burners due to:

• Overheating of the spark electrode

• Poor fuel atomization leading to delayed or unstable ignition

• Low combustion air temperature

• Excessive safety valve lift

For boilers operating above 150 bar and 500°C, the most suitable construction material is:

• Cast iron for high conductivity

• Aluminum alloys for lightweight design

• High-strength alloy steel to resist creep and thermal fatigue

• Brass for corrosion resistance

Why are fire tube boilers rarely selected for utility-scale power generation?

• They require higher-grade fuel

• They consume more water per unit steam

• They cannot safely handle very high pressures and capacities

• They need multiple ignition systems

From an industrial perspective, the main advantage of water tube boilers is:

• Lower installation cost at small scale

• Reduced blowdown requirements

• Ability to generate large volumes of high-pressure steam

• Less frequent feedwater treatment

During a hydrostatic test, pressure exceeds the safety limit but valves remain shut. What is the best interpretation?

• Normal during cold test conditions

• Safety valves stuck or improperly calibrated

• Feedwater too cold for expansion

• Control panel sensor error