Top 25 Advanced MCQs on Boiler Control & Interlock Logic for Instrumentation and Control Engineers

Atomizing steam is necessary for fuel oil burners to make sure the spray and combustion are correct. A lot of the time, it’s used as a permissive input.

Interlocks control functions that are important for safety. Certified safety PLCs or hardwired logic make sure that SIL or NFPA standards are met.

A trip in the Burner Management System stops all fuel flow and combustion to keep everyone safe.

The boiler master control changes the fire rate dependent on how much steam the plant needs, making sure that all the burners and loops work together.

Low fuel pressure can make flames unstable, which is why this is the case. Interlock stops the fuel valve from opening to stop dangerous combustion.

If the damper or ID fan fails and the flue gas can’t get out, pressure builds up in the furnace. This is a big safety risk, and it is usually secured.

SIL-rated systems must make sure that safety functions always work the same way, no matter what. It is important that the logic solver is certified to meet SIL integrity and response criteria, especially for important activities like shutting off the fuel.

An incorrect reading of the feedwater flow can throw off the balance of the drum level control loop, which could make the water level unstable.

Without enough ventilation, fuel could build up in the furnace, which could cause an explosion when it is lit.

Too much steam pressure is dangerous. The high-pressure interlock shuts off the burner to stop the pressure from building up.

Voting in 2oo3 gets rid of one bad transmitter that could cause a trip. It makes the system more reliable by filtering out drift or false signals, especially when it starts up or when there are changes.

Oxygen trim adjusts the air-fuel ratio dependent on the amount of oxygen in the flue gas, keeping combustion stable and efficient.

Flame loss is the same as flame scanner failure. To stop the buildup and risk of explosion, the fuel supply must be cut off.

Cross-limiting stops fuel flow from getting ahead of air flow when the load goes up, which lowers the chance of fuel-rich combustion that could cause an explosion.

PLCs are often employed in BMS because they respond quickly, are tough, and can reliably carry out a sequence of tasks.

Losing the flame is a very important event. The MFT system shuts down all the fuel valves so that fuel doesn’t build up.

A fuel selector interlock keeps both fuels from being added at the same time, which keeps the mixing and combustion from being unstable.

A 2003 voting logic makes sure that at least two sensors must agree that there is a flame. This keeps safety and reliability in check in case one sensor fails or sends a false signal.

NFPA 85 establishes rules for safety interlocks and burner management systems for boilers and combustion systems.

The purge cycle gets rid of unburned fuel vapors, which makes sure that the burner starts up safely and stops possible explosions.

Three-element control keeps the drum level stable by making sure that the flow of feedwater, steam, and the drum level are all in sync.

Low drum level can make the tube too hot, which is why. The burner is turned off right away because this is a crucial interlock condition.

Low drum level can make the tube too hot, which is why. The burner is turned off right away because this is a crucial interlock condition.

Flame presence detection is done by UV and IR flame scanners, which let BMS logic respond quickly and accurately.

Flame detection is a safety feature that makes sure the burner flame is on when it is being used. When the flame goes out, the gasoline stops.

A BMS is in charge of safely sequencing the introduction of fuel, ignition, flame monitoring, and shutdown. Its major purpose is to keep people and equipment safe.