The gaseous state of a substance is the most common in comparison with other aggregate parameters of compounds. Indeed, in this state are:
- stars;
- interstellar space;
- planets;
- atmosphere;
- cosmos as a whole.
The main distinguishing properties of gases are weak intermolecular interactions in the crystal lattice, due to which all the main characteristics of these substances are manifested. There are definitely a lot of gases. However, we will consider the most important and third most common on our planet - natural.
Natural gas composition
If we characterize the qualitative composition of natural gas, then it is immediately necessary to single out the components of two groups: organic and inorganic. Since, although it is commonly believed that it consists of methane, this is not entirely true.
Organic ingredients include:
- methane - CH4;
- propane - C3H8;
- butane - С4Н10;
- ethane - C2N4;
- heavierhydrocarbons with more than five carbon atoms.
Inorganic components include the following compounds:
- hydrogen (in small quantities) - H2;
- carbon dioxide - CO2;
- helium - Not;
- nitrogen - N2;
- hydrogen sulfide - H2S.
What exactly will be the composition of a particular mixture depends on the source, that is, the deposit. The same reasons explain the various physical and chemical properties of natural gas. However, any of them is mined, and each also has a value. It's just that some kind is used as a fuel, and saturated with foreign impurities is too fatty used in the chemical industry for the synthesis of compounds.
Physical and chemical properties of natural gas
To specify such parameters exactly, you should know what exactly the composition of the gas mixture is. After all, if it is dominated by methane (up to 97%), then the characteristics can be given, focusing on it.
If there is an excess of inorganic components or heavy hydrocarbons (up to several percent), then the physical and chemical properties of natural gas change dramatically.
Therefore, only approximate physical limits can be specified.
- Auto-ignition temperature - 650-7000C.
- Octane number - 120-130.
- No color, taste or smell.
- Lighter than air almost 2 times, easily concentrated in the upper layers of the room.
- Density in the form of a normal state (gas) - 0, 68-0,85 kg/m3.
- Under standard conditions, always be in a gaseous aggregate state.
- When mixed with air in volumes of 5-15%, it is explosive.
- Heat of combustion is about 46 MJ/m3.
In addition, the chemical side of natural gas parameters should also be noted.
- It is a highly flammable substance, capable of self-ignition with and without a spark at a certain temperature.
- Since the main component is methane, it has all of its chemical properties.
- Enter into substitution, dehydrogenation, pyrolysis, refraction reactions.
- Compresses and liquefies at low temperatures and high pressures.
Obviously, such physical and chemical properties of natural gas determine a wide range of its use in industry.
Special property of natural gas
A special property of the compound in question is the ability to form gas hydrate deposits, that is, to be in a solid state. These structures represent volumes of natural gas absorbed by formation water molecules in the ratio 1/220. Therefore, such deposits are extremely rich rocks. Places of their concentration in nature:
- deep bottom layers of the oceans;
- accumulations of permafrost.
Existence conditions - hydrodynamic pressure and low temperatures.
Natural gas fields
If we talk about the content of naturalgas in nature, it is possible to identify the main places of concentration:
- This is a sedimentary rock, a mineral that has been formed over many millennia by the anaerobic decay of organic matter in the deep layers of the earth's crust.
- Dissolved in groundwater.
- Includes in oil, forming an oil and gas cap over it.
- Occurs in the form of gas hydrates in the layers of the seabed and points of the Far North.
If we denote the distribution of gas fields territorially, then the leaders are the following countries:
- Russia.
- Gulf countries.
- USA.
- Canada.
- Iran.
- Kazakhstan.
- Azerbaijan.
- Uzbekistan.
- Norway.
- Turkmenistan.
- Netherlands.
Production in the world is annually about 3643 billion m3 per year. Of these, only Russia accounts for 673.46 billion m3.
The temperature of natural gas at which it burns is 650 0C. That is, this is the indicator at which it is capable of self-ignition. In this case, a greater amount of thermal energy is released than during the combustion of any other type of fuel. Naturally, this could not but affect the areas of use of this substance.
That is why many countries that do not have natural gas reserves are forced to import it from other states. Transportation is carried out in several ways:
- through pipeline in gaseous state;
- in tanks by sea - in liquid form;
- inrailway tank cars - liquefied.
Each path has its advantages and disadvantages. In particular, sea and railway options are safer, since the chemical activity of liquefied gas in refrigerated cylinders is much lower than in a gaseous state. The pipeline increases the transmission distance and its volumes, in addition, this method is economically viable.
Methane in natural gas
Methane gas is the main raw material component of the natural mixture. Its content ranges from 70-98%. By itself, this is the third most common gas on the planet, which is part of oil, interstellar space, and the atmosphere of other planets.
From the point of view of chemistry, methane gas is a saturated hydrocarbon belonging to a number of saturated aliphatic compounds. The very first representative of alkanes or paraffins. Its chemical activity is low, it is quite calm. Reactive:
- replacement;
- complete oxidation;
- conversions.
It burns with a colorless non-smoking flame, has no smell.
Types of natural gas
There are three main types of the substance in question.
- Dry natural gas is one in which more than 97% methane is present. That is, the content of impurities, including other hydrocarbons, is extremely low.
- Skinny gas. This is the name of a mixture containing a small amount of heavy hydrocarbons.
- Fatty natural gas is one that is rich in heavy hydrocarbons and inorganic components (nitrogen, hydrogen, helium, argon, carbon dioxide, hydrogen sulfide).
Such a concept as the coefficient of dryness of gas, allows you to evaluate the quality of raw materials from which products will be manufactured in the future. After all, natural gas itself is only a base. Different industries require different products, so they are meticulously processed and refined to meet specific requirements.
Product quality
The quality of natural gas directly depends on the composition. If methane predominates, then such a product will be the best source of fuel. If most of all in the composition of fatty hydrocarbons, then for the chemical industry such raw materials are the most suitable.
In order to supply natural gas of the right quality, there are special chemical plants where it undergoes thorough cleaning and processing before further shipment to the final destination. Working methods will depend on the intended use of the product.
So, for example, if it is used for domestic purposes, then special odorants, in particular mercaptans, are added to it. This is done so that the gas begins to smell, because then in the event of a leak it will not be difficult to detect. All mercaptans have a strong odor.
Use of natural gas
Natural gas consumption by many industriesindustry and facilities. For example:
- CHP.
- Boiler rooms.
- Gas engines.
- Chemical production (manufacturing of plastics and other materials).
- Fuel for cars.
- Residential heating.
- Cooking food.
That's why the world's production of this raw material is so high, and imports and exports are estimated at billions of dollars.
Environmental
In terms of cleanliness for nature, there is no better source of fuel than natural gas. Environmental organizations fully endorse its use. However, in recent years, the combustion of natural gas leads to the accumulation of one of the reaction products - carbon dioxide.
And since it belongs to greenhouse gases, its accumulations are very dangerous for the planet. Therefore, multiple works are being carried out, projects are being developed to protect the ecological state of the planet from the impending greenhouse effect.
