Carbon dioxide from capture units in coal plants or industrial units will be tapped. The gas will then be transformed into liquid state. This carbon dioxide in liquid state will be injected under high pressure into rock deep underground coal beds. This will in turn pump the methane out of the coal beds, which can then be collected and used as fuel.The pores left empty by methane will be occupied by the injected carbon dioxide, thereby preventing it from polluting the atmosphere.
The research assumes significance since India is the fourth largest emitter of carbon dioxide, which affects both environment and health. According to a study conducted in 2014, India was the fourth biggest emitter of carbon dioxide (CO2), a whopping 2.6 billion tones that year, contributing 7.2 per cent of the world’s emissions. Furthermore, in 2016, another report cited India as becoming the world’s fastest-growing major polluter, with the largest increase in global CO2 emissions at 5.3 per cent. Carbon dioxide, when released into the atmosphere, is known to remain for around 100 years.
“Natural gases have remained trapped in deep underground rock structures for several million years. This provided the idea to inject and store the greenhouse gases in rocks and prevent their release into the atmosphere,” said Vikram Vishal, assistant professor, department of earth sciences at IIT-B.
Studies have estimated that the total annual carbon emissions in India will increase by about 2.5 times — from 1,229 metric tonnes in 2005 to approximately 3,084 metric tonnes in 2030.
“Last year, I created underground conditions in my own laboratory and used carbon dioxide for the first time. We evaluated the geo-mechanical conditions of the coal reservoir. Real time conditions in the laboratory have added to my research,” said Vishal.
In addition to capturing and storing carbon dioxide in the coal beds, the research paper also deals with the recovery of methane from the same beds used to retrieve CO2. While conventional methods lead to the retrieval of 40 percent methane, Vishal’s discovery will recover 70-75 percent.
Vishal had also won the Young Scientist Award at the Indian Science Congress in 2011.
“Realising India’s vast geological diversity, the country offers ample opportunities for the storage of carbon dioxide. Injection of carbon dioxide will not only help develop a long sustainable earth, but also lead to enhanced recovery of methane to partly meet our growing energy demands,” said Vishal.