LA Steam Engineer Licence Exam with Questions and Answers

LA Steam Engineer Licence Exam with Questions and Answers A firetube boiler is experiencing a rapid drop in steam pressure while the fuel input remains constant. Which condition is the most likely cause? a. Excessive blowdown b. High feedwater temperature c. Increased steam demand exceeding boiler output d. Low furnace draft Correct Answer: c. Increased steam demand exceeding boiler output Rationale: Steam pressure drops when steam is leaving the boiler faster than it can be generated. Even with constant firing, a sudden increase in steam demand causes pressure reduction because the evaporation rate cannot immediately match the load requirement. In a watertube boiler, what is the primary reason for using small diameter tubes? a. To increase steam moisture content b. To reduce combustion efficiency c. To decrease circulation velocity d. To improve heat transfer and allow higher pressure operation Correct Answer: d. To improve heat transfer and allow higher pressure operation Rationale: Smaller tubes provide greater surface area relative to volume and withstand higher internal pressures more effectively. This improves heat transfer efficiency and makes watertube boilers suitable for high-pressure applications.