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Burning Ice

posted Jan 28, 2015, 8:59 PM by Ranmini Perera   [ updated Dec 4, 2015, 1:05 AM by Upali Salpadoru ]




Burning Ice,
was earlier found 
only in the outer regions of the solar system. 
Now it has been revealed that vast deposits are waiting to be trapped below permafrost and ocean sediments. This is only a simple compound of carbon bonded to 4 atoms of hydrogen surrounded by a lattice of several water molecules. So it has been named as Methane clathrate or Methane hydrate. [CH4.xH2O]

Fig 1 The yellow shows the methane molecule embedded in ice.

Normal LPG, (Liquefied petroleum gas)  is mostly methane. [CH4];   75 to 80%.  This is used in homes and industrial plants to get energy. The chemical reaction for burning methane is as follows:-
Methane + Oxygen      =  Carbon dioxide+  Water +energy
CH4(gas) + 2 O2(gas)   = CO2(gas) + 2 H2O(liq) ……Producing 891 kilo Joules of energy.

Methane is a colourless, odourless non toxic gas. It melts at 182 °C below zero and boils at -160 °C.  The gas is lighter than air and slightly soluble with the solubility increasing with low temperature and high pressure. Under certain conditions, ice crystalizes around the methane molecule forming methane hydrate. This is the ice that can burn.

Fig2.  Methane clathrane deposits in the world. ( courtsey: World ocean review)

At a time  when the world is yearning for more and more energy, and the known fossil fuel deposits are depleting,  the discovery of enormous deposits of frozen methane in many parts of the world is a godsend. 

Methane was formed by the microorganisms that lived in the sea. Their remains are buried in the ocean sediments. A high temperature of about 30 C  at a depth assist this process. When the gas bubbles up to cooler temperatures it dissolves in the water and gets embedded in an envelope of ice crystals as methane calthrate.

Dr. George Hooper
of the Canterbury University in New Zealand, a few years back said, ““There is a huge potential in Frozen gas deposits.  It could contain Methane hyudrate,  just 22km.off the south Wairarapa coast and 80km from ..Wellington. …Half a trillion cubic feet of gas ..  

The melting of which would increase the volume over hundredfold”. It was also his opinion that it would take at least 10 to 15 years to develop the technology to extract the gas at a commercial scale.

According to a news item in ‘the guardian.com’ on 12/3/2013 Japan has developed the technology and is already extracting the gas, The technique had been to reach the solid methane and ice layer  situated over a kilometre deep and reduce the pressure. This changes the state from solid to liquid and the liquid mixture could easily be pumped up . After separating the water the liquefied gas could easily be stored in steel cylinders.                             

‘Times of India’ has confirmed this on 17/3/13,  For India too ,  “Light at the end of the tunnel comes from a technological breakthrough last week by JOGMNC. It succeeded in extracting natural gas from sea-bed deposits of methane hydrate…... India has some of the biggest methane hydrate reserves in the world. It will reap a bonanza if technological progress allows gas to be extracted from hydrates economically and safely. Japan .. is contemplating commercial gas production maybe as early as 2016”

The melting of ice caps due to global warming has already induced the release of methane into the sea water. This methane uses up the oxygen dissolved in the water changing to carbon dioxide.  This causes a twofold detrimental act to the oceans.  Depleting of life sustaining gas oxygen and the increasing of acidity.
The technology developed by Japan is to reduce the pressure on the deposits to change the solid state to a liquid state.  Then the mixture of liquid methane and water to be pumped up from a well.   This is a very risky operation as an excessive reduction can break up a large portion of the deposit and release the gas to the sea and atmosphere.

An alternative method that is being developed  is to pump carbon dioxide into the deposits. In the laboratory trials it has been found that carbon dioxide  can get into the methane clathrate releasing the methane.  This method is beneficial in two ways.  First it can yield the methane gas in a mre controlled manner. The other is that it would be a solution to the increasing carbon dioxide levels in the atmosphere. “If, carbon dioxide is stored as a hydrate within the cold deep sea floor, it would be much safer, because CO2 hydrates are considerably more thermally stable than methane hydrates”




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