Pulverized solid fuel is burned primarily for___________________?
Show answer Hide answer
Answer: A. better burning
Explanation
Pulverizing solid fuel increases its surface area exposed to oxygen for better burning. Finer particles mix intimately with combustion air, resulting in rapid and complete chemical reactions. This enhanced burning rate maximizes thermal energy release within boiler furnace combustion chambers. Coal is ground into a fine powder resembling face powder before being blown into burners. High surface-area-to-volume ratio accelerates the ignition and flame propagation phases significantly. Suspension burning allows solid fuels to behave somewhat similarly to gaseous or liquid fuels.
Large thermal power plants utilize pulverized coal boilers to generate high-pressure steam efficiently. Optimizing combustion reduces unburned carbon loss in ash and minimizes harmful emissions. This technology enables efficient utilization of solid mineral fuels for large-scale electricity generation. More calorific value is an intrinsic chemical property of the fuel independent of particle size. Less radiation loss depends primarily on furnace insulation design rather than fuel preparation methods. Stoker fired boilers typically burn larger lump coals rather than pulverized fine dust suspensions.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. The dimensionless ratio relating fluid inertia forces to elastic forces is designated as__________________?
Show answer Hide answer
Answer: A. Mach number
Mach number is the dimensionless ratio representing the speed of a fluid relative to the speed of sound. This parameter directly relates fluid inertia forces to elastic forces within compressible aerodynamic flow fields....
Q2. A refrigerating system operates with a suction pressure of 10 kg/cm² gauge and condensing pressure of 67 kg/cm². What is the refrigerant________________?
Show answer Hide answer
Answer: B. Carbon dioxide
Carbon dioxide operating pressures are notably high, with typical suction and condensing pressures matching these values in CO2 refrigeration systems. Refrigeration cycles utilizing carbon dioxide operate at exceptionall...
Q3. System accumulators must possess sufficient internal volume to hold a refrigerant charge of at least_________________?
Show answer Hide answer
Answer: C. 50%
System accumulators are specifically designed to safely hold at least fifty percent of the total refrigerant charge. This volumetric capacity prevents liquid refrigerant from flooding back into the compressor during load...
Q4. Vapor absorption refrigeration systems normally employ which working fluid combination___________________?
Show answer Hide answer
Answer: E. ammonia
Vapor absorption refrigeration systems commonly use an ammonia-water working fluid combination where ammonia acts as the refrigerant. Ammonia possesses exceptional thermodynamic properties that make it highly effective f...
Q5. Recrystallization temperature is characterized as the threshold________________?
Show answer Hide answer
Answer: B. at which new spherical crystals first begin to form from the old deformed one when a strained metal is heated
Recrystallization temperature marks the point where new strain-free crystals nucleate and grow within a previously deformed metal. Heating a plastically deformed metal past its recrystallization threshold triggers the fo...
Q6. Anhydrous ammonia as a working fluid is __________________?
Show answer Hide answer
Answer: D. highly toxic and inflammable
Anhydrous ammonia is classified as a hazardous chemical because it is both toxic and flammable. Inhalation of high concentrations poses severe health risks, while specific air mixtures can ignite readily. Safety standard...