Combustion Prelim

COMBUSTION

is a chemical reaction that produces heat when a material quickly interacts with oxygen

Combustion Chemistry

The study of the high-temperature exothermic chemical reaction between a fuel and an oxidant usually atmospheric oxygen

fuel

is a material that, when burned, releases energy and heat, frequently in the form of chemical or thermal energy

Types of Fuel

solid fuel, liquid fuel, fuel gas, biofuel, fossil fuel

Liquid Fuel

e created when fossilized plant and animal remnants are exposed to extreme heat and pressure

Solid Fuel

These were probably the earliest fuels that humans used

Fuel Gas

gaseous and readily transportable for consumption

Biofuel

can exist as a gas, liquid, or solid. The sole requirement is that it must come from biomass. Thus, it is basically regenerative fuel made from living things

Fossil Fuel

Because of high pressure and temperatures, conventional fuels—which are non-replenishable and generated over thousands of years

Relation of Heat Transfer to Combustion

For effective energy conversion and real-world uses, combustion depends on heat transmission processes including conduction, convection, and radiation. These processes move thermal energy from hotter to cooler fluids and from hotter to colder areas inside or between solids

Coal

A combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds. It's a fossil fuel formed from ancient plant matter that has been subjected to heat and pressure over millions of years.

Peat

An accumulation of partially decayed vegetation or organic matter that has been preserved underwater in bogs, swamps, or marshes. It's an early stage in the formation of coal.

Briquettes

Compressed blocks of combustible materials like coal dust, charcoal, wood chips, sawdust, or biomass. They are often used as a more convenient and uniform fuel source

Wood

The fibrous structural tissue found in the stems and roots of trees and other woody plants. It's used as a fuel in the form of firewood, pellets, or chips.

Charcoal

A lightweight black residue, consisting of carbon and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. It's produced by heating wood in the absence of oxygen.

Waste Products

This category encompasses a variety of combustible materials derived from waste streams, including agricultural residues, municipal solid waste, and industrial byproducts. These can be processed and used as solid fuels for energy recovery.

Earth's Crust

This is the only layer where solid fuels exist. Essentially any solid fuel that is of organic origin, or that is mined, will be found within the earth’s crust. Here, you can find:

Coal

Formed in sedimentary layers from ancient plant matter.

Peat

Found in wetland environments

Biomass

Including wood, agricultural residues, and other organic materials.

Anthracite

• This is the highest grade of coal.

• It's known for its high carbon content.

• It burns cleanly with a blue flame and produces little smoke.

• It is hard coal.

Bituminous

- This is a mid-range coal.

- It's widely used for generating electricity and in industrial processes.

- It has a high heating value.

- It produces more smoke than anthracite.

Sub-bituminous

- This is a lower-rank coal.

- It has a lower carbon content and higher moisture than bituminous coal.

- It is used in electrical power generation.

Lignite

- This is the lowest rank of coal, often called "brown coal."

- It has the lowest carbon content and the highest moisture.

- It has the lowest heating value.