About Hydrogen:
- It is an energy carrier that can be used to store, move, and deliver energy produced from other sources.
- At STP, it is a nontoxic, odorless, tasteless, colorless, and highly combustible diatomic gas(H2).
- It has the highest energy per mass of any fuel. However, its low ambient temperature density results in a low energy per unit volume.
- Occurrence-Naturally, it is the most abundant element in the universe.
- The sun and other stars are composed largely of hydrogen. Astronomers estimate that 90% of the atoms in the universe are hydrogen atoms.
- Hydrogen is a component of more compounds than any other element.
- Water is the most abundant compound of hydrogen found on earth.
- Molecular hydrogen is not available on Earth in convenient natural reservoirs. Most hydrogen on Earth is bonded to oxygen in water and to carbon in live or dead and/or fossilized biomass.
- Preparation– Its preparation could be done by breaking the chemical bonds from compounds. A few common methods include electrolysis, from steam(splitting water into hydrogen and oxygen) and hydro carbon or carbon, reaction of metals with acids, ionic metal hydrides with water, etc.
- Storage– Due to its low ambient temperature density resulting in a low energy per unit volume, it requires the development of advanced storage methods that have potential for higher energy density. It can be stored physically as either a gas or a liquid.
- Storage as a gas typically requires high-pressure tanks.
- Storage as a liquid requires cryogenic temperatures because the boiling point of hydrogen at one atmosphere pressure is −252.8°C.
- Hydrogen can also be stored on the surfaces of solids (by adsorption) or within solids (by absorption).
Hydrogen- a clean fuel:
- It is a clean fuel that, when consumed in a fuel cell, produces only water.
- Hydrogen fuel production methods- The most common methods today are natural gas reforming (a thermal process), and electrolysis. Other methods include solar-driven and biological processes.
Thermal processes for hydrogen production:
- It involves steam reforming, a high-temperature process in which steam reacts with a hydrocarbon fuel to produce hydrogen.
- Many hydrocarbon fuels can be reformed to produce hydrogen, including natural gas, diesel, renewable liquid fuels, gasified coal, or gasified biomass.
- Today most of all the hydrogen produced is from steam reforming of natural gas.
Electrolytic processes for hydrogen production:
- Water can be separated into oxygen and hydrogen through a process called electrolysis.
- Electrolytic processes take place in an electrolyzer, which functions much like a fuel cell in reverse—instead of using the energy of a hydrogen molecule, like a fuel cell does, an electrolyzer creates hydrogen from water molecules.
Solar driven processes for hydrogen production:
It uses light as the agent for hydrogen production. There are a few solar-driven processes, including photo biological, photo electrochemical, and solar thermochemical.
- Photobiological processes use the natural photosynthetic activity of bacteria and green algae to produce hydrogen.
- Photo electrochemical processes use specialized semiconductors to separate water into hydrogen and oxygen.
- Solar thermochemical hydrogen production uses concentrated solar power to drive water splitting reactions often along with other species such as metal oxides.
Biological processes for hydrogen production:
- Biological processes use microbes such as bacteria and microalgae and can produce hydrogen through biological reactions.
- In microbial biomass conversion, the microbes break down organic matter like biomass or wastewater to produce hydrogen, while in photobiological processes the microbes use sunlight as the energy source.
Hydrogen production in India:
Hydrogen is a by – product in Chlor – Alkali industries. Earlier, a part of it was used for non – energy applications and rest was either flared or vented out in the atmosphere.
- By 2013 – 14 around 90% of by – product hydrogen was utilized for production of chemicals and captive (mainly energy) applications.
Hydrogen is produced for non – energy applications e.g. in fertilizer industries and petroleum refineries.
