ANS:C - Light diesel oil

Among the options provided, Light diesel oil does not typically require preheating during storage in the storage tank as well as during atomization through burners. Here's why:

1. Light Diesel Oil: Light diesel oil, also known as automotive diesel or diesel fuel, is a type of fuel used in diesel engines for automotive and industrial applications. It is designed to be relatively easy to atomize and ignite compared to heavier fuels.
2. Preheating Requirements:
   • PCM (Petroleum Coke Meal): PCM is a solid residue derived from petroleum refining processes. It may require preheating for easier handling and processing.
   • Tar: Tar, which can be a byproduct of various processes, is typically thick and viscous. Preheating helps reduce its viscosity and facilitates handling and burning.
   • Low Viscosity Furnace Oil: Furnace oils are heavy, viscous fuels used in industrial boilers and furnaces. Low viscosity furnace oil still requires preheating to reduce its viscosity and improve atomization during combustion.
3. Light Diesel Oil: Light diesel oil is lighter and more volatile compared to tar and furnace oils. It is designed to atomize easily at ambient or slightly elevated temperatures, making preheating less necessary for both storage and combustion.

Therefore, among the options listed, light diesel oil is the fuel that generally does not require preheating during storage in the tank or during atomization through burners, due to its relatively low viscosity and ease of combustion compared to heavier fuels like tar and furnace oils.