Previously, during oil refining, enterprises were forced to burn liquid methane with the help of torches, as they were not able to transfer condensate for subsequent petrochemical processing. Now they have learned to transport and use it in many areas of industry. At the same time, it is well stored and does not form harmful impurities during combustion.
Physical and chemical properties of methane
Methane belongs to the simplest hydrocarbons. It is lighter than air, non-toxic, poorly soluble in water, has no tangible smell. It is believed that methane is not dangerous to humans, but there are known cases of its effects on the central and autonomic nervous system. Accumulating indoors, at a concentration in the air from 4% to 17% it becomes explosive. Therefore, to detect it by humans (without instruments), special substances often resemble the smell of gas are often added to methane. Refers to greenhouse gases. In methane, weak narcotic properties are manifested, which are weakened by low solubility in water.
By origin, as a result of compounds with various substances and chemical reactions, it is divided into:
- biogenic (organic);
- abiogenic (inorganic);
- bacterial (vital activity of microorganisms);
- thermogenic (thermochemical processes).
This gas is also obtained in the laboratory by heating soda lime or anhydrous sodium hydroxide with frozen acetic acid.
Methane in the liquid state occupies a volume 600 times less than in the gaseous one. Therefore, for ease of transportation and storage, it is liquefied. Liquid methane is a colorless, odorless liquid. It retains almost all the properties of gas. The critical pressure of liquid methane is 4.58 MPa (the minimum at which it turns into a liquid).
Existence in nature
Methane is part of and is the main constituent of the following gases:
- natural (up to 98%);
- oil (40-90%);
- wetland (99%);
- mined (35-50%);
- mud volcanoes (over 94%).
It is also contained in the water of the oceans, lakes, seas. Present in the atmosphere of such planets as Earth, Saturn, Jupiter, Uranus, and in the surface gases of the moon. A large amount is contained in coal seams. This makes mining in closed tunnels an explosive activity.
Natural Gas Liquefaction Technology
Pure methane is obtained from natural gas, removing other components from it: ethane, propane, butane and nitrogen. To obtain liquid methane, the gas is compressed, followed by cooling. The liquefaction process is done in cycles. At each stage, the volume will decrease up to 12 times. It turns into a liquid in the last cycle. Different types of plants are used for liquefaction, among them:
- throttle;
- turbine-vortex;
- turbo expander.
The following schemes may be used:
The cascade scheme uses three agents for cooling. At the same time, the temperature of liquid methane decreases in stages. This technology requires high capital costs. Currently, this process has been improved and a mixture of refrigerants (ethane and propane) was immediately used. Such a scheme has become self-cooling, since these substances are obtained from liquefied natural gas. Costs have decreased slightly, but still remain high.
When applying an expansion scheme, more economical centrifugal machines are used. The mixture is preliminarily purified from water and other impurities and liquefied under pressure due to heat exchange with a cold expanded gas stream. However, this process requires a greater expenditure of energy than with the cascade scheme (25-35%). But at the same time, capital costs are saved on compressors and equipment operation.
The temperature of liquid methane obtained by the above process is an average of 162 degrees.
Methane use
The scope of methane, both in gaseous and in liquid state, is very extensive. It is used as fuel, in the form of raw materials for industry, in everyday life, as anabolic steroids for building muscle mass.
With incomplete combustion, soot is obtained from methane, which is widely used in industry: in the production of rubber, stamp paint, shoe polish, etc. They are also used for the production of hydrocyanic and acetic acid, methanol, acetylene, ammonia, carbon disulfide, as a combustible gas (perpetual the fire).
Liquid methane is used as motor fuel for automobiles. He has an octane number 15% higher than gasoline, as well as high calorific value and antiknock properties. According to reviews, liquid methane burns out almost completely, and when the appropriate equipment is correctly installed on the car, a rather significant saving occurs compared to gasoline (when traveling long distances).
This gas is actively used for the production of drugs that increase muscle mass. On its basis, such products as Dianoged, Danabol, Nerobol are produced, which are in greatest demand. It is believed that these drugs have a positive effect on the human body:
- strengthen bones;
- stimulate the formation of sexual characteristics;
- burn fat;
- increase stamina;
- accelerate protein synthesis.
However, it is important to remember that all drugs have side effects, so you need to take them under the supervision of a doctor.
Based on the foregoing, we can conclude that the production of liquid methane is a very promising area of modern industry.