Thursday 26 December 2019

Gas hydrates or methane hydrates a Future energy source

GAS HYDATES as an energy

What are the gas hydrates or methane hydrates?
How gas hydrates are produced?
Discus the geological condition for it's occurrence?
India's expedition to explore and exploit program called as Indian national Gas Hydrates programme (expedition -1 & 2)?
Merits and demerit of exploration?
Technology development to harness this resource?
World and India resource potential of gas hydrates reserves?
Mapping.


    Gas hydrates are ice like crystalline solid structure formed of water and gas. These solid mineral structure called clatherate mineral. Here, low molecular weight gas such as methane, ethane ,Co2, combines with water and freezes into a solid under low temperature and moderate high pressure conditions. Most of the gas hydrates are formed from methane or it is also called as methane hydrates.

On earth gas hydrates occurs in the permafrost areas and marine sediments. These gas hydrates deposits if properly harnessed then it has following merits..
1) gas hydrates contain the energy double the total conventional fossil fuels combined together (coal, oil and natural gas).
2) it can trigger landslides and tsunamis or earthquakes because of sudden release of pressurised methane gas.
3) release of methane gas into atmosphere intensify the impact of green house effect and climate change.
4) it is associated with hydrocarbons and hydrogen sulfide by chemosynthesis process can support unique biological communities.

Formation condition for gas hydrates :-

Methane hydrates are found in two types of environment 1) beneath the permafrost in Arctic regions and 2) deep in the ocean at the depth of 1500-3000 m below 200-300 m in the continental shelf.
Here marine organism after decay produced methane which is trapped in the water molecules when temperature is below 10 degree Celsius and pressure more the 30 bars. If temperature increases more pressure is required. So, Arctic waters are found at the depth of 300 m but in Tropical water body at the depth of 600 m. Hydrates or Clathrates is a matrix of ice found mixed with sediments.

Potential reserves of gas hydrates :-
 Methane hydrates has great potential to transform the energy sector market. It will be beneficial to countries like China and India which are net importer of natural gas, indigenous production help them to reduce the burn on foreign exchange and balance of trade, accelerate the GDP, generate jobs, support the ancillary industries
In the world till Now no commercial project of gas hydrates mining exist. Just few project started by USA, Japan, China and India.
As per the general scientific estimates the global gas hydrates availability is more that the double of total oil and gas. But, actual figures yet to be accounted.

Ideal site for gas hydrates project are :
1) high concentration of hydrates 2) reservoir rocks with high permeability 3) availability of infrastructure 4) economical and viable technology to extract 5) government policy and incentives to develop this energy.

Technology development is taking place with the joint project between USA and Japan and individual R&D is being established by concern Earth science ministry.
There are two ways to extract it
1) depressuring the hydrates rocks and 2) thermal approach here heating by passing carbon di oxide is being tried.
By 2020 technology will be available for commercial use said by Japan.

Indias national gas hydrates programme passes through two phases with joint initiative with USA and Japan. Under expedition 1 nothing much exploitable found but in phase two(expedition 2) large quantity is being discovered in the Bay of Bengal basin especially Krishna-Godavari delta and mahanadi delta in 2015-16. There is a great potential in konkan basin and sunderban delta.
In the world gas hydrates found in north Alaska coast by USA, Arctic coast of Russia, south China sea by China, off coast of Japan.

Challenges are :
1) technology is at initial stage of development. 2) cost of exploration and exploitation is very high. 3) site of exploration is far away from coast 4) environmental threats like tsunamis, landslide, earthquake, 5) it is a GHG can contribute to global warming and climate change.








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