Achieving easy ignition and prolonged flames requires coal with_________________?
Show answer Hide answer
Answer: A. High volatile matter
Explanation
High volatile matter provides abundant combustible gases that ignite easily upon heating. These released gases burn rapidly and sustain a long, stable flame front. Coals with high volatile content react much faster than low-volatile anthracite varieties. Volatile matter consists of hydrocarbons and other gases driven off when coal is heated. Easily liberated gases lower the activation energy required to start steady combustion. Longer flames result from the extended distance needed to burn all released volatiles.
Boilers designed for utility power generation perform best with high-volatile bituminous coals. Easy ignition ensures stable burner operation during cold boiler startup procedures. Proper volatile content prevents unstable flame extinction and unburned fuel losses. Low ash content improves heating value but does not directly control ignition ease. High calorific value is beneficial, but volatile matter specifically dictates flame length. High ash content hinders combustion and causes operational problems rather than helping flames.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Fixed carbon within coal is characterized as______________________?
Show answer Hide answer
Answer: C. Hundred minus the percentage of volatile matter, ash and moisture
Proximate analysis calculates fixed carbon by subtracting volatile matter, ash, and moisture. One hundred percent represents the total mass fraction of the original coal sample. The remaining balance after accounting for...
Q2. Which fuel gas pair exhibits a volumetric calorific value (kcal/Nm3) for one fuel that is nearly double the other, while their weight-based calorific values (kcal/kg) remain identical?
Show answer Hide answer
Answer: A. Propane and acetylene
Propane and acetylene have identical weight-based calorific values when measured on a mass basis. Their volumetric calorific values differ by a factor of nearly two due to distinct molecular densities. Stoichiometric com...
Q3. Fossil fuels are defined as___________________?
Show answer Hide answer
Answer: C. Those fuels which are found in the crust of earth
Fossil fuels originate from the buried remains of ancient plants and animals over millions of years. Geological processes trap these carbon-rich organic deposits within the Earth crust. Mining and drilling extract these...
Q4. Large thermal power facilities typically expel flue gas through chimneys at velocities around ________________ m/sec?
Show answer Hide answer
Answer: B. 10
Large thermal power plants discharge exhaust gases through tall chimneys at high velocities. Design standards typically target exit velocities around ten meters per second. This velocity prevents the flue gas from being...
Q5. The froth flotation technique is applied for_________________?
Show answer Hide answer
Answer: A. Washing fine coal dust (< 0.5 mm size)
Froth flotation relies on surface property differences to effectively wash and clean fine coal dust. Hydrophobic coal particles attach to air bubbles and float, while hydrophilic mineral ash sinks away. Particle sizes be...
Q6. Coke production fuel consumption can be lowered by___________________?
Show answer Hide answer
Answer: D. All A., B. and C.
Preheating coal reduces the thermal energy required inside the coking chamber walls. Blending optimizes charge properties while dry quenching recovers sensible heat from hot coke. All these advanced engineering practices...