METHANE

1. METHANE Known and unknown facts R.Carmassi I.T.I. Malignani - Udine

2. For half a century this blue flame has represented a steady source of energy for our industrial and domestic needs. Everyday we use methane (we also call it “natural gas”) which is delivered to our gas company by a pipeline and to our homes by a complex network of small diameter pipes. Natural gas is almost pure methane and we use it to cook, to warm water and to keep our homes comfortably warm in winter. R.Carmassi I.T.I. Malignani - Udine

3. Natural gas was actually known to the ancients, but it was considered by them to be a supernatural manifestation. Noticed only when ignited, it appeared as a mysterious fire bursting from fissures in the ground. Natural gas seeps were discovered in Iran between 6000 and 2000 B.C. The use of gas was mentioned in China about 900 B.C. Count Alessandro Volta concluded in 1776 that there was a direct correlation between the amount of decaying organic matter and the amount of flammable gas produced. In 1808, Sir Humphrey Davy determined that methane was present in the gases produced during the anaerobic decomposition of cattle manure. Apparently, natural gas was unknown in Europe until its discovery in England in 1659. However, since manufactured gas (coal gas) was already commercially available, natural gas remained unpopular. R.Carmassi I.T.I. Malignani - Udine

4. In the 19th century gas produced from coal was used to light houses, as well as streetlights. Till the 1950s the same gas was distributed in the cities for cooking and warming purposes. Starting from the 1950s, long pipelines have been built to transport natural gas and the gas from coal (it is toxic because it contains carbon monoxide) is no more used. R.Carmassi I.T.I. Malignani - Udine

5. As an example, the natural gas we use in Italy is transported from Russia and Algeria by long pipelines . Natural gas was found and exploited in the Po valley near Cortemaggiore but it could satisfy only local needs. R.Carmassi I.T.I. Malignani - Udine

6. Methane has a tetrahedral molecule (the image is in background) with a carbon atom at the centre and four hydrogen atoms bonded to it. chemical formula CH4 melting point –182.5°C boiling point –161.6°C Methane reacts with oxygen producing carbon dioxide, water, energy: CH4 + 2 O2 CO2 + 2 H2O(l) + 890.4 KJ One mole of methane ( 16 g ) produces 890.4 KJ One Kg of methane produces 55650 KJ One m3 of methane at 0°C and atmospheric pressure produces 39750 KJ R.Carmassi I.T.I. Malignani - Udine

7. In the previous slides common facts about natural gas were exposed, together with some chemical explanation. In the next slides we are going to examine less known facts about methane in a sort of solid state, examining scientific,energetic and environmental aspects. R.Carmassi I.T.I. Malignani - Udine

8. Gas hydrates are crystalline solids which look like ice, and which occur when water molecules form a cage-like structure around smaller 'guest molecules'. The most common guest molecule in natural hydrates is methane, CH4. In this figure the methane is shown at the center, trapped in a cage of water molecules. Gas hydrates (also called clathrates) were discovered in 1810 by Sir Humphrey Davy, and were considered to be a laboratory curiosity. R.Carmassi I.T.I. Malignani - Udine

9. For more than a century this “solid gas” had been only a scientific curiosity but… In the 1930s methane hydrate formation turned out to be a major problem, clogging pipelines during transportation of natural gas in arctic regions. In the 1960s, naturally-occurring methane hydrate was observed in Siberian gas reservoirs. R.Carmassi I.T.I. Malignani - Udine

10. As the understanding of natural methane hydrate grew, scientists realized that, given the ubiquity of both methane (the common by-product of bacterial breakdown of organic matter) and water in nature, methane hydrate could be present in vast quantities in any environment with suitable pressures and temperatures. Since the 1970s, expeditions to polar regions and deep-water continental shelves all over the globe have consistently returned reports of methane hydrate. Today, the U.S. Geological Survey estimates that methane hydrate may, in fact, contain more organic carbon than all the world's coal, oil, and non-hydrate natural gas combined. R.Carmassi I.T.I. Malignani - Udine

11. Methane hydrate deposits were discovered all over the world. In the future they could be an important source of energy. BUT… They have to be investigated also from an environmental point of view because they could cause changes in the world climate and huge catastrophes. R.Carmassi I.T.I. Malignani - Udine

12. Methane hydrate is a like-ice solid mixture which is stable at high pressures and near zero temperatures.It acts as a cement in wide areas of the ocean floor. Natural occurring temperature variations (or variations produced by mining) can transform this solid mixture into water and gaseous methane with two effects: A: the methane is dispersed into the atmosphere. If a big amount of it is released a catastrophic climate change might occur. Some mass extinction in the past are suspected to have been produced by such phenomena. This is because methane is a powerful greenhouse gas (more powerful than carbon dioxide). B: if it acts as a cement, when it decomposes an under sea landslide may occur. Destructive tsunamis were caused by sudden breaking down of methane hydrate layers. R.Carmassi I.T.I. Malignani - Udine

13. Greenhouse Effect What is it? Solar radiation interacts with the surface of the earth in several  ways. Some of the energy from the sun is reflected back into space by the earth's atmosphere.  Another portion is dispersed and scattered by the molecules in the atmosphere. A large portion penetrates the atmosphere to reach the surface of the earth. Radiation reaching the earth's surface is largely absorbed, resulting in surface warming. R.Carmassi I.T.I. Malignani - Udine

14. Much of this absorbed energy is eventually re-radiated in longer infrared wavelengths. As it leaves the earth, it once again interacts with the atmosphere. Some of this re-radiated energy escapes to space, but much is reflected back to the earth's surface by molecules in the earth's atmosphere. This reflected energy further warms the surface of the earth. The molecules, eg water vapour H2O(g), nitrous oxide N2O, methane CH4, and carbon dioxide CO2, responsible for this phenomenon are called greenhouse gases,  because they act like the glass in a greenhouse, trapping energy. Without these gases most life on earth would not be possible, as the surface temperature of the earth would probably be about 15°C colder.  In essence, greenhouse gases act like a blanket above the earth, keeping the heat in. Increasing the concentration of these gases in the atmosphere increases the atmosphere's ability to block the escape of infrared radiation. In other words, the earth's insulation gets thicker. Therefore, an increased concentration of greenhouse gases can have dramatic effects on climate and significant repercussions upon our world. Conditions suitable for human life exist within a finite window - a limited range of greenhouse gas concentrations that makes life as we know it possible.  R.Carmassi I.T.I. Malignani - Udine

15. Physics of Tsunamis The phenomenon we call a tsunami (soo-NAH-mee) is a series of waves of extremely long wave length and long period generated in a body of water by an impulsive disturbance that displaces the water. Tsunamis are primarily associated with earthquakes in oceanic and coastal regions. Landslides, volcanic eruptions, nuclear explosions, and even impacts of objects from outer space (such as meteorites, asteroids, and comets) can also generate tsunamis. As the tsunami crosses the deep ocean, its length from crest to crest may be a hundred miles or more, and its height from crest to trough will only be a few feet or less. They can not be felt aboard ships nor can they be seen from the air in the open ocean. In the deepest oceans, the waves will reach speeds exceeding 600 miles per hour (970 km/hr). When the tsunami enters the shoaling water of coastlines in its path, the velocity of its waves diminishes and the wave height increases. It is in these shallow waters that a large tsunami an crest to heights exceeding 100 feet (30 m) and strike with devastating force. R.Carmassi I.T.I. Malignani - Udine

16. And now… Some exercise …. R.Carmassi I.T.I. Malignani - Udine

17. Fill in the gaps….. Natural gas is almost pure ……… and we use it to cook, to warm water and to keep our homes comfortably warm in winter. Count Alessandro Volta concluded in 1776 that there was a direct correlation between the amount of decaying ……… matter and the amount of flammable gas produced. In 1808, Sir Humphrey Davy determined that methane was present in the gases produced during the …………. digestion of cattle manure. In the 19th century gas produced from …… was used to light houses, as well as streetlights. With these missing words….. -deposits - boiling -hydrogen – hydrates – natural -methane –formula -organic – tetrahedral –water - anaerobic- coal – dioxide - R.Carmassi I.T.I. Malignani - Udine

18. Fill in the gaps….. Methane has a …………….. molecule with a carbon atom at the centre and four …………… atoms bonded to it. chemical ……….. CH4 melting point –182.5°C ………. point –161.6°C Methane reacts with oxygen producing carbon ……….., water, energy With these missing words….. -deposits - boiling -hydrogen – hydrates – natural -methane –formula -organic – tetrahedral –water - anaerobic- coal – dioxide - R.Carmassi I.T.I. Malignani - Udine

19. Fill in the gaps….. Methane ………… are crystalline solids which look like ice, and which occur when …….. molecules form a cage-like structure around methane molecules. Methane hydrate ………. were discovered all over the world. In the future they could be an important source of energy. Today, the U.S. Geological Survey estimates that methane hydrate may, in fact, contain more organic carbon than all the world's coal, oil, and non-hydrate ……… gas combined. With these missing words….. -deposits - boiling -hydrogen – hydrates – natural -methane –formula -organic – tetrahedral –water - anaerobic- coal – dioxide - R.Carmassi I.T.I. Malignani - Udine

20. This is the end of this presentation…. OR…. It would be better if this were the beginning of your own work about this topic. R.Carmassi I.T.I. Malignani - Udine