What Is A Fuel?

key notes :

  • Fuels: Substances which provide energy on burning in air are called fuels. They may be of various types:
    • Solid fuels such as wood, coal, cowdung cakes, charcoal (prepared from wood)
    • Liquid fuels like kerosene (also known as  Mitti ka tel), petrol and diesel.
    • Gaseous fuels such as CNG (Compressed Natural Gas), LPG (Liquefied Petroleum Gas) and coal gas.
    • Fuel cells are a type of energy conversion technology which take the chemical energy contained within a fuel and transform it into electricity along with certain by-products (depending on the fuel used). [1] It’s important to note that fuel cells are not heat engines, so they can have incredibly high efficiencies. However, when a heat engine is used to power a fuel cell, the heat engine still has a limiting thermal efficiency.
    • Fuel cells can be seen as an energy storage device, as energy can be input to create hydrogen and oxygen, which can remain in the cell until its use is needed at a later time. In this sense they work much like a battery. There are multiple types of fuel cells, but two common types are the solid oxide fuel cell (SOFC) and the polymer electrolyte membrane fuel cell (PEMFC).
    • Figure 1. A diagram of a solid oxide fuel cell (SOFC). Molecular oxygen becomes oxide ions (O2-) and combines with hydrogen to form water, while simultaneously producing electricity.[2]
    • Figure 2. A diagram of a polymer electrolyte membrane fuel cell (PEMFC). Molecular hydrogen fuel becomes hydrogen ions (H+) that travel through a polymer electrolyte. The hydrogen ions combine with oxygen to form water, while simultaneously producing electricity.[3]
    • To produce electricity in a solid oxide fuel cell, oxygen in the air combines with free electrons to form oxide ions. The oxide ions travel through a ceramic electrolyte and react with molecular hydrogen to form water. The reaction that makes water also releases electrons which travel through an external electrical circuit, producing electricity.[4] This process can be seen in figure 1.
    • To produce electricity in a polymer electrolyte membrane fuel cell, a gaseous fuel is input and reacts with a catalyst made of platinum nanoparticles. When molecular hydrogen comes into contact with this, it splits into two H+ ions and two electrons. The electrons are conducted through an electromotive force and electricity is produced. The hydrogen ions pass through a proton exchange membrane (also known as a polymer electrolyte) where it reaches the cathode and combines with oxygen to form water. This process can continue as long as there is hydrogen and oxygen supplied to the cell.[1] Figure 2 shows this process in a PEMFC.
    • The video below from NASA illustrates how oxygen and hydrogen come together in a solid oxide fuel cell (SOFC) to release energy which can be snagged in a useful way.

key idea :-

  1. Introduction to Fuel:
    • Fuel is a substance that releases energy when it undergoes a chemical or physical change.
    • It is essential for various processes, especially in powering vehicles, generating electricity, and heating homes.
  2. Types of Fuels:
    • Fossil Fuels:
      • Derived from ancient organic materials.
      • Examples: coal, petroleum (oil), natural gas.
      • Formed over millions of years through heat and pressure.
    • Renewable Fuels:
      • Derived from renewable resources.
      • Examples: biomass (wood, agricultural waste), biofuels (biodiesel, ethanol), solar energy, wind energy.
      • Considered environmentally friendly as they are replenished naturally.
  3. Energy Conversion:
    • Fuel contains stored energy that can be released through combustion (burning) or other chemical reactions.
    • The released energy can be transformed into various forms, such as heat, light, or mechanical energy.
  4. Combustion Process:
    • Most fuels undergo combustion to release energy.
    • Combustion involves a chemical reaction between the fuel and oxygen (oxidation).
    • Common byproducts of combustion are carbon dioxide (CO2), water vapor (H2O), and sometimes pollutants like carbon monoxide (CO).
  5. Energy Sources and Uses:
    • Different fuels are used for various purposes:
      • Gasoline and diesel for transportation.
      • Natural gas for heating and electricity generation.
      • Coal for electricity and industrial processes.
      • Biomass for cooking and heating.
  6. Environmental Impact:
    • Burning fossil fuels releases greenhouse gases, contributing to global warming.
    • Renewable fuels have a lower environmental impact as they produce fewer emissions.
  7. Energy Efficiency:
    • Not all fuels release the same amount of energy for a given quantity.
    • Energy efficiency is a measure of how much useful energy is obtained from a fuel.
    • Different fuels have different energy densities and efficiencies.
  8. Future Trends:
    • Shift towards cleaner and more sustainable energy sources.
    • Increasing use of electric vehicles and renewable energy technologies.
    • Research into new fuels and energy storage solutions.
  9. Conclusion:
    • Fuels are vital for modern life, powering various activities and technologies.
    • Understanding different types of fuels and their impacts helps us make informed choices for a sustainable future.

Let’s practice!