Coal Classification and Properties

Coal Classification and Characteristics

• Bituminous coal has an average calorific value of 31350 kJ/kg
• Bituminous coal can be caking or non-caking
• Non-caking coal is softer than anthracite and burns with minimal smoke
• Semi-bituminous coal contains 15-20% volatile matter and tends to break into small pieces during storage or transportation
• Semi-anthracite coal contains less fixed carbon and luster compared to anthracite and produces longer, more luminous flames when burned
• Anthracite is a very hard coal with a shiny black luster. It ignites slowly unless the furnace temperature is high, burns with very short blue flames or without flames, and is a popular domestic heating fuel.

Coal Composition and Properties

• Coal contains minerals that are transformed into ash when burned.
• Fixed carbon is the solid combustible residue remaining after volatile matter is expelled from a coal particle during heating.
• A high fixed carbon content indicates a longer combustion time for coal.

Coal Testing and Analysis

• Proximate analysis determines the moisture, volatile matter, fixed carbon, and ash content of coal.
• Ultimate analysis provides a precise chemical composition of coal in terms of carbon, hydrogen, oxygen, nitrogen, sulfur, and ash.

Coal Utilization

• Combustion involves burning coal in air to release thermal energy.
• Carbonization is the heating of coal to high temperatures in the absence of air.
• Conversion processes transform coal into gaseous or liquid fuels, known as synthetic fuels.

Manufactured Solid Fuels

• Charcoal is derived from the destructive distillation of wood and burns rapidly with a clear flame, producing no smoke.
• Soft coke is obtained from the destructive distillation of coal between 600-650°C and contains 5-10% volatile matter.
• Hard coke is obtained from the destructive distillation of coal between 1200-1400°C and burns with smoke.
• Briquettes are compressed small pieces of coal, lignite, peat, or coke into a regular shape with or without a binder.

Liquid Fuels

• Liquid fuels possess a higher calorific value per unit mass, burn without dust, ash, or clinkers, and are easily transported through pipes.
• Liquid fuels are more expensive than solid fuels and require special storage tanks.

Petroleum

• Petroleum is a dark greenish brown, viscous mineral oil mainly composed of hydrocarbons (paraffins, cycloparaffins, olefins, and aromatics).
• Petroleum is classified into paraffinic base type, asphaltic base type, and mixed base type.

Main Products of Petroleum

• Asphalt is used in road construction and is a colloid of asphaltenes and maltenes.
• Diesel is fuel used in diesel engines and is denser than gasoline.
• Fuel oil is a liquid petroleum product burned in furnaces to generate heat.
• Gasoline is used as fuel in internal combustion engines and is a mixture of paraffins, naphthenes, and olefins.
• Kerosene is used as jet fuel and heating fuel and is a thin, clear, combustible liquid.
• Liquefied Petroleum Gas (LPG) is a mixture of gases primarily used for heating, aerosols, and refrigerants.
• Lubricating oil consists of base oils and additives and is classified as paraffinic, naphthenic, or aromatic.
• Paraffin wax is a white, odorless, tasteless waxy solid used as an electrical insulator and in drywall insulation.
• Bitumen, also known as tar, is a thick, black, sticky material used in paving roads and waterproofing roofs and boats.

Explore the various types of coal, including bituminous, semi-bituminous, semi-anthracite, and anthracite. Learn about their characteristics, calorific values, and compositions. This quiz offers insights into coal's properties, helping you understand their applications in heating and energy.