Coal is an important industry in India, providing fuel for the growing nation. However it leaves a huge environmental footprint from the gases that are emitted into the atmosphere as it is mined, including carbon dioxide and methane.It is estimated that at the current rate of carbon dioxide emissions, the earth cannot avoid a rise of at least 2 degrees Celsius in the average atmospeheric temperature.
Vikram Vishal, a research scholar at the IITB-Monash Research Academy is looking at ways to not only reduce these emissions, but also how to capture the natural gas. The research looks at “geologic sequestration”, or capturing the carbon dioxide that is released when the coal is burnt (or created as a by-product in other industries) and injecting it back into the rock deep underground so that it is not released into the atmosphere.
Coal naturally contains methane, a natural gas that is low carbon and a cleaner fuel, however it is trapped in the rock. When coal is mined, methane is also released into the atmosphere and becomes a pollutant with a greenhouse impact 21 times that of carbon dioxide. Currently it is possible to access approximately 45% of the methane trapped in coal prior to it being mined, but the remainder is trapped until the rock is mined. Being able to capture methane before it goes into the environment will have the dual benefit of both saving a natural gas and reducing greenhouse emissions.
India is the 4th largest emitter of carbon dioxide in the world. As its economy grows, it is important for India to start leading the way in reducing its emissions and finding new ways to create energy sources. It is this, that forms the basis for Vikram Vishal’s research at the IITB-Monash Research Academy.
Vishal has approached his research in two parts. The first part is experimental, whereby he is looking at how coal can be injected with the carbon dioxide that has been emitted. The intention here, is for the carbon dioxide to then be stored underground, without being released into the atmosphere, thereby reducing greenhouse emissions.As coal already stores methane gas, by injecting carbon dioxide into the coal, the methane gas will then be released, enabling it to be captured before it is released into the environment.
By designing a new experiment to inject carbon dioxide into coal samples, Vishal then evaluates how the characteristics of the coal change at various temperatures and pressures. These experiements test for changes in the permeability of the coal, hydromechnical response of the coal, swelling synthesis, how the fracture sensitivity reduces, how much gas it can absorb and how long this takes. Furthermore, when carbon dioxide is injected into coal, it can change the strength of the substance, affects the stability of the injection system and can result in a leakage of gas. This also needs to be monitored as part of the experiments to ensure gas does not inadvertently enter the atmosphere.
The experiment also monitors unconventional behaviour of the coal when it is injected. As carbon dioxide is injected into the coal it changes from liquid to supercritical phase, which then changes the behaviour of the coal that is receiving it. This also requires monitoring to ensure that the behaviour of the coal can be predicted.
The second part of Vishal’s research then uses this labarotary data, along with data collected in the field at specific coal mining sites (including Jharia and Raniganj, to develop a computer model to predict what will happen when this is implemented practically. The model looks at the conditions in the field, the current rate of methane production at those sites, the characteristics of the specific coal in that site etc.
Whilst other countries in the world have conducted similar experiments and are implementing similar types of programs, this has never been done in India before. It is imperative that site specific research is done, as the behaviour of coal differs from one coal basin to another, and can even differ within one basin. The specific characteristics of the coal and how it will respond may differ, and therefore studies based in other locations cannot be applied in India.
Issues such as the integrity of the rock are critical to ensure the success of the process. Therefore Vishal’s work measuring, monitoring and verifying the rock, and then understanding what will happen to it over time is so important.By ensuring we understand the amount that can be injected, the flow of the gas and the position of the rock, long-term safety can be assured.
Reflecting on his research, Vishal comments “Natural gases have remained trapped in deep underground rock structures for several million years. This provides an analogy to inject and store the greenhouse gases in rocks and prevent their release into the atmosphere. Realising India’s vast geological diversity, she 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. “
IITB-Monash Research Academy is a Joint Venture between IIT Bombay and Monash University. Research scholars study for a dually-badgedPhD from both institutions, and enrich their research and build collaborative relationships by spending time in Australia and India over the course of their degree. Established in 2008, IITB-Monash Research Academy aims to enhance scientific collaborations between Australia and India.
With the fourth largest coal reserves in the world, India can contribute greatly to improving the global environment. Coincidentally, many industries that are high carbon dioxide emitters also happen to be located close to coal reserves, which makes the potential impact of Vishal’s research even greater. The ability to inject carbon dioxide safely into coal, at minimal cost by course syncing industries, provide favourable conditions for the application of this research.
The true beneficiary of this process will be the life-system on Earth.Through the enhanced recovery of an otherwise non-recoverable resource, India will also benefit from energy security.
Research Scholar: Vikram Vishal, IITB-Monash Research Academy
Project Title: Experimental and numerical investigation of carbon dioxide sequestration and recovery of methane from coal seams.
Supervisors: Professor T N Singh and Associate Professor P G Ranjith
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The above story was written by Ms Rakhee Ghelani based on inputs from the research student and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.