A reactive flash volatilisation (RFV) gasification technology is being used to produce hydrogen using microalgae, giving rise to newer and cleaner forms of energy.
A project completed last week (12th Feb), saw researchers confirm that hydrogen production using RFV on microalgae is 36% less compared to the steam reforming of methane gas – the current best practice for hydrogen production.
The research, published in the Journal of Cleaner Production, also shows that with the prevailing cost of hydrogen at $10 per kilo, and using RFV to produce the gas, the payback period of initial investment was just 3.78 years with a 22% internal rate of return.
Academics at Monash University’s Department of Chemical Engineering, IITB-Monash Research Academy Mumbai, and The Indian Institute of Technology’s Department of Chemical Engineering worked on the project.
“Hydrogen and methane are clean sources of fuel and green chemical synthesis only if they are produced from renewable resources. At present, 96% of hydrogen and all methane is produced using non-renewable resources,” Associate Professor Akshat Tanksale from Monash University and research co-author said.
“Microalgae as a feedstock is attractive due to its high carbon dioxide fixation efficiency, growth rate, photosynthetic efficiency, ability to grow in brackish water – like rivers and lakes – and the ability to cultivate it on land not suitable for agriculture.”
“Water and renewable electricity integration with microalgae harvesting can bring down the costs and increase the sustainability of hydrogen production from this process.”
Researchers performed the RFV of microalgae using temperatures ranging from 550-650°C using steam as the gasifying agent. This meant the dewatering or drying of microalgae wasn’t required and significantly reduced energy consumption.
Using India-based JSW Steel (the funding agency for this research) as a case study for their source of CO2 for microalgae cultivation, the research team estimated just under 12,800 kg an hour of microalgae would be available for hydrogen production at a rate of 1240 kg/h.
While the costs to develop infrastructure to cultivate microalgae and then refine it into hydrogen and methane are expensive, the overall return on investment in the long-term could make hydrogen and methane cost-effective and environmentally friendly fuel sources.
“Assuming a market price of $10/kg for hydrogen compressed to 700 bar pressure, the payback period for hydrogen production was 3.78 years with nearly 25% investment return,” said Dr Pratik Gholkar, Research student at IITB-Monash Research Academy Mumbai.
“Moreover, the life cycle climate change impact was 7.56 kg of carbon dioxide for every kilogram of hydrogen produced.”
“This is an exciting look into the resources and technology available to the world in our quest to reduce the use of fossil fuels and drastically cut the amount of carbon emissions.”