Clean Fuel Hydrogen | 08 Feb 2021

Why in News

Recently, researchers at the Indian Institute of Technology, Delhi (IIT-D) have come up with a way to generate clean fuel hydrogen from water at a low-cost.

  • It is a significant step towards efforts across the globe that are being made to look for cleaner and greener energy sources.
  • Hydrogen gas is a viable choice as a renewable substitute for fossil fuels, and can help mitigate emissions to reduce pollution.

Key Points

  • About:
    • The researchers at IIT-D have successfully split water by a process known as Sulphur-Iodine (SI) thermochemical hydrogen cycle (SI Cycle) to generate low-cost, clean hydrogen fuel for industrial consumption.
    • Generally in SI Cycle, the separation of Hydrogen from oxygen requires a high amount of heat (generally from non-renewable sources such as coal, oil and natural gas). This makes the large-scale production of hydrogen gas economically non viable and non environment friendly.
    • The main achievement has been designing a suitable catalyst for the energy intensive, corrosive step of sulphuric acid conversion to sulphur-dioxide and oxygen.
  • Sulfur-Iodine Cycle
    • Process:
      • The sulfur–iodine cycle (SI cycle) is a three-step thermochemical cycle used to produce hydrogen. In this cycle, all the chemicals are recycled. The SI process requires an efficient source of heat.
      • Heat enters the cycle in high-temperature endothermic chemical reactions in the initial process and heat exits the cycle in the low-temperature exothermic reaction in the final stage of obtaining hydrogen gas.
    • Three-Step Thermochemical Cycle:
      • Step 1: Iodide (I2) is reacted with Sulphur dioxide (SO2) to produce Hydriodic acid (HI) and Sulphuric acid (H2SO4).
        • I2 + SO2 + 2 H2O → 2 HI + H2SO4
      • Step 2: The water, SO2 and residual H2SO4 is separated from the oxygen byproduct by condensation so as to obtain Hydriodic acid (HI).
        • 2 H2SO4 → 2 SO2 + 2 H2O + O2
      • Step 3: It is the Hydriodic acid (HI) from which Hydrogen gas (H2) is obtained.
        • 2 HI → I2 + H2
      • The difference between the heat entering and leaving the cycle exits the cycle in the form of the heat of combustion of the hydrogen produced.
    • Major challenges of the sulfur–iodine cycle are to reduce the surplus of water and iodine and find separation processes that consume less energy than distillation.
    • Traditionally development of the SI cycle has been pursued by several countries for hydrogen production with the Generation IV nuclear reactors.
  • Significance of the Discovery:
    • Enhancing Hydrogen Fuel Cell Technology:
      • Enabling availability of of low cost hydrogen through this discovery will enhance and improve the application of Hydrogen fuel cell technology which offers the advantages of a clean and reliable alternative energy source to applications such as – electric vehicles, primary and backup power for a variety of commercial, industrial, and residential buildings; and more futuristic-sounding applications like air taxis.
        • A hydrogen fuel cell is an electrochemical power generator that combines hydrogen and oxygen to produce electricity, with water and heat as by-products.
    • Help Adhering Emission Targets:
    • Complements FAME India Scheme:
      • It will complement the implementation of the FAME India Scheme launched with the objective to support hybrid/electric vehicles market development and manufacturing ecosystem.
  • Advantages of Hydrogen as Fuel:
    • Environment Friendly:
      • The advantage of using hydrogen as an energy carrier is that when it combines with oxygen the only byproducts are water and heat.
      • No greenhouse gasses or other particulates are produced by the use of hydrogen fuel cells.
    • Non Toxic:
      • Hydrogen is a non-toxic substance that is rare for a fuel source. It is environmentally friendly and does not cause any harm or destruction to human health.
    • Highly Efficient:
      • Hydrogen is an efficient energy type since it has the ability to convey a lot of energy for every pound of fuel compared to diesel or gas.
    • Ideal Spaceship Fuel:
      • Hydrogen energy’s efficiency and power make it an ideal fuel source for spaceships. Its power is so high that it’s able to quickly rocket spaceships to exploration missions.
  • Disadvantages of Hydrogen as fuel
    • Compared to gas, hydrogen lacks smell, which makes any leak detection almost impossible.
    • Hydrogen is a highly flammable and volatile substance, its potential dangers make its transportation and storage very challenging.