Scientists at the Indian Institute of Science (IISc) have developed an environment-friendly way of producing hydrogen from biomass, an abundant renewable energy source.
The researchers noted that India uses nearly 50 lakh tonnes of hydrogen for various processes in different sectors, and the hydrogen market is expected to grow substantially in the coming years.
"But most of the hydrogen we currently use comes from fossil fuels through a process called steam methane reforming route," said S Dasappa, a professor at IISc's Centre for Sustainable Technologies.
Now, his team has found a way to extract green hydrogen from biomass in a two step process.
In the first step, biomass is converted into syngas -- a hydrogen-rich fuel gas mixture -- in a novel reactor using oxygen and steam.
In the second step, pure hydrogen is generated from syngas using an indigenously developed low-pressure gas separation unit. Both these technologies ensure that this process is a highly efficient method of generating green hydrogen, the researchers said.
The technology produces 100 grammes of hydrogen from 1 kilogramme (kg) of biomass even though only 60 grammes of hydrogen are present in 1kg of biomass.
This is because in this process, steam, which also contains hydrogen, participates in both homogeneous and heterogeneous reactions.
In homogeneous reactions, reactants are in a single phase whereas in heterogeneous reactions, the reactants are in two or more phases.
The production of green hydrogen using this process is environmentally friendly as it is carbon negative.
The two carbon-based by-products are solid carbon, which serves as a carbon sink, and carbon dioxide, which can be used in other value-added products.
The project was supported by the Ministry of New and Renewable Energy and the Department of Science and Technology of the Government of India.
The team also acknowledges the support of the Indian Oil Corporation Limited in scaling up the technology to produce 0.25 tonnes of hydrogen per day for use in hydrogen-powered fuel cell buses.
Dasappa believes that green hydrogen could be used in several other industries as well -- in the steel industry to decarbonise steel, in agriculture to manufacture green fertilisers, and in many sectors currently using hydrogen produced from fossil fuels.
"Moreover, the same platform can be used for methanol and ethanol production," he added.
