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energy

Some curiosities about methane hydrates

Not only energy

The melting of the ice cells, not only brings about the release of methane gas, but it also produces another important substance: fresh water. Hence, methane hydrates are also a reserve of fresh water that could be used for drinking purposes. The energy and the costs involved in producing it could, in a few years, be lower than the costs of desalinating sea water and making it drinkable: drinking water could, in practise, be the ‘waste product’ in the production of methane from hydrates.
Another possible utilization of the unique property of methane to form hydrates has been studied in Norway so as to be able to transport methane in the most economical way. Currently, methane is transported in its liquid form, usually with appropriate ships. To bring about the change of state from gas to liquid, methane has to be kept at a temperature of – 180°C, that implies a very high cost and energetic consumption. To be able to transform it into methane hydrates, that are stable at a temperature of only – 15°C, would lead to an enormous reduction not only in terms of costs but also of the energy required for the process to take place. It would also have an advantage in terms of safety: methane hydrates burn but do not explode.
Problematic compounds
Methane hydrates have been known for some time because they are also the cause of technical problems. For example, undesired methane hydrates are formed in the methane pipelines of Arctic regions due to the low temperatures.
During the drilling process, when exploiting deposits on the sea floor or in areas of permafrost, the presence of methane hydrates heated by the friction of the perforation heads triggers off the release of great quantities of gas. Methane is explosive and inflammable and can become a source of danger. Besides the danger of fires and explosions, the release of great quantities of gas into the water can bring about turbulence on the surface, that can in turn create problems to the drilling equipment and to the boats close by.
A curious fact
Some researchers have put forward a fascinating hypothesis: the area around the Bermudas coincides with one of the areas  of the planet that are richest in hydrates. In areas where great quantities of methane have been released due to the destabilization of hydrates beneath the sea floor, sea water suddenly becomes very rich with gas bubbles and churns up becoming less dense. The decrease in the density of water diminishes the upthrust and causes the sinking of any passing boats… This could help to explain some other details too, such as the constant presence of a ‘fog’ at the time of disappearance, but it cannot explain the disappearance of aeroplanes… It is a fascinating hypothesis but slightly on the borders of reality and not yet approved by the scientific community.

With the sponsorship of the Italian Ministry of Education, Universities and Research
 
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