Light at the End of the Tunnel

– By Syeda Qudsia, NUST Science Blog

Our situation is very much like being in a tunnel at the end of which many of us glimpse a light… Wait. How do I break it to you? Sure it was there… but now it’s gone! Sacrificed for the cause of load-shedding! The kind of light that lights up the end of tunnels is no more (R.I.P.), but there is another kind of light getting brighter with it, and it’s coming from under the ground in southern Sindh.

We need an energy solution, quick and fast, and we all are very familiar with how Pakistan is a country rich in minerals and how we have HUGE reserves of coal and gas.

How huge?

Well, in 1992, the Geological Survey of Pakistan discovered 185 billion ton of coal reserves spread out beneath 9,000 square kilometers of sand dunes in Thar Desert.

And how big is that?

It is one of the largest coal reserves in the world, making Pakistan’s coal reserves almost equal to the equivalent of 618 billion barrels of crude oil as compared to the current 260 billion barrels of Saudi reserves of crude oil!

The thing is now to get those reserves to light up our homes, offices, and the end of the tunnels (which, of course, are very important). And for that, we just came up with Underground Coal Gasification to do the trick! No, it isn’t us; it’s Dr. Samar Mubarakmand, one of the most reputable and respected person, and mentor of NUST Science Society.

Underground Coal Gasification provides us energy from the very basic principles of energy generation – combustion, or partial combustion. We all know how we can get energy if we were to burn up a mass of coal. That’s just what the process of underground coal gasification does; only it does it underground. This makes it much more economical and environment friendly, as the harmful emissions this process produces are lesser and much more controllable than those emitted by surface gasification process.

For this, wells are built that lead right into the reservoir: some to serve as injection wells for the introduction of oxidants, air or steam into the reservoir, to fuel the process of combustion; and some as production wells for resultant gases. The temperatures inside the reservoir can reach up to 700-900 °C generally but it can rise up to as much as 1500 °C. At temperatures as high as these, the flow of oxidants can be monitored to control the process and to produce a multitude of gaseous products, like carbon dioxide, hydrogen, carbon monoxide, and methane. Other gases, like sulfur dioxide and some nitrogen oxides may also be produced, depending on impurities present in the coal. So, you do not need to make up a whole furnace for this process, nor do you have to transport the coal anywhere from its place, which makes all this very economical.

Now what makes Thar coal so highly appropriate for this purpose?

Obviously, you cannot carry out this procedure on any coal deposits present underground. For UCG, you need a depth of 100-600 meters; well, Thar coal reservoirs are 150 meters deep. It requires a thickness of more than 5 meters; for which our reservoir has a thickness ranging from 0.2 to 36 meters. Thirdly, ash content should be less than 60 %; and in Thar coal, it is only about 5.18 % to 6.56 %. What’s more, Thar coal is spread for about 9,000 km2! And although there are water reservoirs present above, below and along the reservoir level, the water in there is brackish to saline in nature, making it of zero value for use. Its low sulfur content (about 0.92 – 1.34 %) makes it even more environment friendly. Eureka!

This is being done now, right here. Dr. Samar Mubarakmand and his team have successfully produced gas using UCG in Thar. The gas produced will be utilized to generate electricity, and the by-produced gases like carbon monoxide and hydrogen can be used to produce petroleum products, turning around our economy, and fate of our masses; because this, when functional, will produce cheap electricity in abundance, making Pakistan self-sufficient in electricity generation. And this, once started, can go a long, long way!

And how long is long?

Well, believe us, you don’t have to worry about it for the next 800 years!


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