Acetylene is an unsaturated hydrocarbon. This compound, as well as its various homologues, serve as raw materials for the synthesis of a large number of chemical products.
Properties and production of acetylene
Acetylene is a colorless gas at atmospheric pressure and normal temperature. If the temperature drops to -85 degrees and below, then this connection goes into another state - solid. In this case, crystals are formed. It should be noted that in the liquid and solid state, acetylene can easily explode under the influence of friction or upon impact (hydraulic or mechanical). It is this property that largely determines its scope. Acetylene combustion reactions occur in the presence of oxygen. As a result of this process, a flame is produced that is characterized by the highest temperatures (3150 degrees) compared to other types of fuel.
The main way to produce acetylene is a reaction in which calcium carbide and water interact. This process takes place at a temperature of about 2000 degrees and is endothermic.
There is such a thing as an exitacetylene. This is its amount, which is released as a result of the decomposition of 1 kg of calcium carbide. GOST 1460-56 establishes specific values for this value, which is directly dependent on the degree of granulation of the initial substance. Thus, a consequence of the relatively small particle size of calcium carbide is a decrease in the yield of acetylene.
This pattern is a consequence of the presence of foreign impurities in fine particles of carbide, such as calcium oxide.
There are other, less cumbersome, expensive and energy-intensive ways to produce acetylene. For example, the reaction of thermo-oxidative pyrolysis of methane from natural gas; decomposition of oil, kerosene and other fuels by electropyrolysis.
Storage and transportation
All methods of storage and transportation involve the use of cylinders. They are filled with a special mass of porous consistency. It is impregnated with acetone, which dissolves acetylene well. The use of this method allows you to significantly increase the filling capacity of the acetylene cylinder and, importantly, reduces its explosiveness.
Prolonged contact of acetylene with metals such as copper and silver can increase its explosiveness. Therefore, materials that may contain these metals, such as valves, should not be used.
As a rule, cylinders must have special valves designed specifically for storageacetylene.
Full utilization of the entire capacity of the cylinder can be achieved by storing empty containers so that the acetone is distributed throughout the entire volume of the cylinder. And this is only possible in a horizontal position. Filling the balloon should be very slow, which is important to comply with the conditions of the chemical reaction of dissolving acetylene in acetone, and in particular its speed.
Benefits of dissolved acetylene
The main advantage of dissolved acetylene over that obtained using portable calcium carbide generators is that when using cylinders, the welder's labor is increased by about 20%, and acetylene losses are reduced by 25%. It should also be noted the increase in the efficiency and maneuverability of the welding post, safety. Unlike the gas obtained from calcium carbide, dissolved acetylene contains significantly less foreign substances, that is, impurities, which allows it to be used in especially critical welding work.
Main applications of acetylene
- Welding and cutting of metals.
- Using a bright, white light source. In this case, we are talking about acetylene, obtained by the interaction of calcium carbide and water. In this case, autonomous lamps are used.
- Production of explosives.
- Obtaining other compounds and materials, which are acetic acid, ethyl alcohol, solvents, plastics, rubber, aromatic hydrocarbons.
Acetylene: application in construction andindustry
Autogenous and welding works accompany almost all stages of construction. It is in these types of work that acetylene is used. In a special device called a burner, the gases are mixed and the combustion reaction itself takes place. The highest temperature of this reaction is reached when the content of acetylene is 45% of the total volume of the cylinder.
Cylinders with this gas are labeled as follows: they are painted white and in large red letters the inscription: "Acetylene"
Construction work is carried out mainly in the open air. The use of acetylene and its homologues under these conditions should not take place under the influence of direct sunlight. Short breaks should be accompanied by closing the valves on the burner, and long ones - by closing the valves on the cylinders themselves.
Acetylene is in high demand in the chemical industry. Its application consists in the use of this substance in the process of obtaining products of organic synthesis. These are synthetic rubber, plastics, solvents, acetic acid, etc.
Acetylene, being a universal fuel, is often used in processes accompanied by flame treatment. It is important that the use of acetylene in industry is possible only if safety measures are observed, since it is an explosive gas.
Carbide lamps
The name "carbide lamp" is due to the use of openflame jet of burnt acetylene. It is, accordingly, obtained as a result of the interaction of calcium carbide with water.
Such lamps were widespread in the past. They could be seen on carriages, cars and even bicycles. In modern times, carbide lamps are used only in case of urgent need for a powerful autonomous lamp. So, speleologists often use them. Remote beacons are supplied with just such lamps, because this type of lighting is much more profitable than laying down power lines. It is quite common to use such lamps on seagoing ships.
Acetylene: medical applications
How is the substance used in this area? General anesthesia involves the use of alkynes. Acetylene is one of those gases that are used in inhalation anesthesia. But its widespread use in this capacity is a thing of the past. Now there are more modern and safer methods of anesthesia.
Although it should be noted that the use of acetylene did not pose a great danger, since before the value of its concentration in the inhaled air reaches a dangerous limit, the lower flammability threshold will be passed.
The most important condition for the use of this gas is compliance with safety measures. It is difficult to overestimate how dangerous acetylene is. Its use is possible only after all the necessary briefings with employees of various fields in which itin use.
