Understanding Fuels and Lubricants

What is the definition of fuel?

• A method of transportation.

• A type of renewable energy source.

• A substance that provides energy through combustion or chemical reaction.

• A chemical element found in nature.

What are the two main classifications of fuels?

• Biomass fuels and chemical fuels

• Natural gases and electric fuels

• Fossil fuels and synthetic fuels

• Renewable fuels and non-renewable fuels

List three characteristics of a good fuel.

• Low boiling point

• High viscosity

• High water content

• High energy content, easy ignition, minimal pollutants

Define higher calorific value and lower calorific value.

• Higher calorific value is measured in grams per liter.

• Higher calorific value (HCV) includes latent heat of vaporization; lower calorific value (LCV) excludes it.

• Lower calorific value includes the heat of combustion only.

• Higher calorific value is always lower than lower calorific value.

How is the calorific value of solid or liquid fuel determined using a bomb calorimeter?

• The calorific value is determined by measuring the temperature change in water after combustion of the fuel in a bomb calorimeter.

• By calculating the weight of the fuel before combustion.

• By analyzing the chemical composition of the fuel.

• By measuring the pressure change in the bomb calorimeter.

What is proximate analysis of coal?

• Proximate analysis evaluates the energy output of coal.

• Proximate analysis focuses solely on the carbon content of coal.

• Proximate analysis measures the sulfur content of coal.

• Proximate analysis of coal measures moisture, volatile matter, ash, and fixed carbon content.

What is the octane number and why is it important?

• The octane number indicates the fuel's boiling point.

• The octane number is a measure of fuel's energy content.

• The octane number measures fuel's color and smell.

• The octane number is a measure of fuel's resistance to knocking, important for engine performance.

What is the cetane number and its significance in fuels?

• The cetane number is a measure of fuel's color and clarity.

• The cetane number measures the density of gasoline.

• The cetane number is a measure of diesel fuel's ignition quality, significant for engine performance and emissions.

• The cetane number indicates the boiling point of diesel fuel.

How does fuel structure influence octane and cetane numbers?

• Higher octane numbers are achieved with longer straight-chain hydrocarbons.

• Fuel structure has no effect on combustion characteristics.

• Fuel structure influences octane and cetane numbers by determining combustion characteristics; branched hydrocarbons increase octane, while straight-chain hydrocarbons enhance cetane.

• Cetane numbers are only influenced by the presence of oxygen in fuel.

What are the chemical compositions of gaseous fuels?

• Acetylene (C2H2)

• Ethanol (C2H5OH)

• Ammonia (NH3)

• Methane (CH4), Propane (C3H8), Butane (C4H10), Hydrogen (H2), and Biogas (CH4 + CO2)