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:
    
    • It could help India to adhere to its commitment in the Paris Climate Agreement and its Intended Nationally Determined Contribution (INDC) Targets and ensure that its mobility in the future is with zero emissions.
  • 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.

Source:TH