The process of producing the optimum amount of a chemical substance, as well as achieving its maximum quality, is influenced by a number of factors. The production of ammonia depends on the pressure, temperature, the presence of the catalyst, the substances used and the way the material is extracted. These parameters need to be properly balanced to achieve the greatest profit from the production process.
Properties of ammonia
At room temperature and normal humidity, ammonia is in the gaseous state and has a very repulsive odor. It is endowed with a poisonous and irritating mucous membrane effect on the body. The production and properties of ammonia depend on the participation in the water process, since this substance is very soluble in normal environmental characteristics.
Ammonia is a compound of hydrogen and nitrogen. Its chemical formula is NH3.
This chemical acts as an active reducing agent, as a result of which free nitrogen is released. Ammonia shows the characteristics of bases and a
Reaction of the substance with water
When NH3 is dissolved in water, ammonia water is obtained. Maximum at the usual temperature, 700 volumes of ammonia can be dissolved in 1 volume of the water element. This substance is known as ammonia and is widely used in the fertilizer industry, in process plants.
Obtained by dissolution in water, NH3 is partially ionized in its properties.
Ammonium alcohol is used in one of the methods of laboratory production of this element.
Preparation of a substance in the laboratory
The first method of obtaining ammonia is to bring ammonia to boiling, after which the steam is drained and the required chemical compound is collected. The production of ammonia in the laboratory is also possible by heating slaked lime and solid ammonium chloride.
The ammonia recovery reaction is as follows:
2NH4Cl + Ca( OH) 2 → CaCl2 + 2NH3 + 2H2O
A white precipitate precipitates during this reaction. This is the salt of CaCl2, and water and the desired ammonia are also formed. To conduct the dehumidification of the required substance, it is passed through a mixture of lime in combination with a soda.
Obtaining ammonia in the laboratory does not provide the most optimal technology for its production in the required quantities. People have been looking for ways to extract matter on an industrial scale for many years.
The origins of the establishment of production technology
During the years 1775-1780, experiments were carried out to bind free nitrogen molecules from the atmosphere. The Swedish chemist C. Shell found a reaction that looked like
Na2CO3 + 4C + N2 = 2NaCN + 3CO
On its basis in 1895 N. Karo and A. Frank developed a method for binding free nitrogen molecules:
CaC2 + N2 = CaCN2 + C
This option required a lot of energy and was economically unprofitable, so over time it was abandoned.
Another cost-effective method was the discovery by the British chemists D. Priestley and G. Cavendish of the interaction of nitrogen and oxygen molecules:
N2 + O2 = 2NO
Growth in ammonia demand
In 1870 this chemical was considered an undesirable product of the gas industry and was practicallyuseless. However, after 30 years it became very popular in the coke-chemical industry.
First, the increased demand for ammonia was replenished by separating it from coal. But with the growth of consumption of the substance 10 times in search of ways to extract it, practical work was carried out. The production of ammonia was introduced using atmospheric nitrogen.
The need for nitrogen-based substances has been observed in virtually all known sectors of the economy.
Finding ways to meet industrial demand
The long journey passed humanity to implement the substance production equation:
N2 + 3H2 = 2NH3
The production of ammonia in the industry was first realized in 1913 by catalytic synthesis from hydrogen and nitrogen. The method was opened by F. Haber in 1908.
Open technology has solved the long-standing problem of many scientists from different countries. Until this point, it was not possible to bind nitrogen as NH3.This chemical process is called the cyanamide reaction. When the temperature of lime and carbon was increased, the substance CaC2( calcium carbide) was obtained. By heating the nitrogen, calcium cyanamide CaCN2 was obtained, from which ammonia precipitation was carried out by hydrolysis.
Introduction of technologies for ammonia production
NH3 production in the global scale of industrial consumption began with the purchase of technology patent F. Haber by the representative of the Baden Soda Plant A. Mittash. In early 1911, the synthesis of ammonia in a small unit became regular. K. Bosch created a large contact apparatus, based on the developments of F. Haber. This was the original equipment, which provides the process of ammonia recovery by synthesis on a production scale. K. Bosch took all the leadership on this issue.
Energy saving meant participation in the synthesis reactions of certain catalysts.
A group of scientists working to find suitable constituents proposed the following: an iron catalyst in which potassium and aluminum oxides were added and which is still considered one of the best providing ammonia in the industry.
9.09.1913 started its work the world's first plant using the technology of catalytic synthesis. Gradually increased production capacity, and by the end of 1917 produced 7 thousand tons of ammonia per month. In the first year of operation of the plant, this figure was only 300 tons per month.
Subsequently, in all other countries, the technology of synthesis with the use of catalysts also began to be used, which in its essence was not very different from the Haber-Bosch technique. The use of high pressure and circulation processes took place in any technological process.
Introduction of synthesis in Russia
Russia also used synthesis with the use of catalysts that produce ammonia. The reaction is as follows:
N2 + 3H2 ↔ 2 NH3 ↑ + 45,9 kJ
In Russia, the very first ammonia synthesis plant began its work in 1928 in Chernorechensk, and then many other cities were built.
Practical work on obtaining ammonia is constantly gaining momentum. Between 1960 and 1970, the synthesis increased almost 7-fold.
In the country, mixed catalytic substances are used for the successful production, collection and recognition of ammonia. The study of their composition is carried out by a group of scientists under the leadership of SS Lachinov. It was this group that found the most effective materials for the synthesis technology.
The process kinetics are also constantly being studied. MI Temkin, as well as his employees, carried out scientific research in this field. In 1938, this scientist together with his colleague VM Pyzhov made an important discovery, improving the production of ammonia. The equation of kinetics of synthesis, compiled by these chemists, is now used throughout the world.
Modern process of synthesis
The process of obtaining ammonia by means of a catalyst, used in today's production, is reversible. Therefore, the issue of the optimal level of impact of indicators on achieving maximum output is very topical.
The process takes place at a high temperature: 400-500 ° C.To ensure the required rate of reaction, a catalyst is used. Modern production of NH3 involves the use of high pressure - about 100-300 atm.
Together with the use of the circulation system, it is possible to obtain a sufficiently large mass of initial materials converted to ammonia.
Modern production of
The system of operation of any ammonia plant is rather complicated and contains several stages. The technology of obtaining the desired substance is carried out in 6 stages. In the process of synthesis, ammonia production is obtained, collected and recognized.
The initial step is to extract sulfur from natural gas using a desulfurizer. This manipulation is required due to the fact that sulfur is a catalytic poison and kills the nickel catalyst even during the hydrogen recovery stage.
At the second stage methane conversion takes place, which takes place using high temperature and pressure using a nickel catalyst.
At the third stage, partial hydrogen burns in the oxygen of the air. As a result, a mixture of water vapor, carbon monoxide, and nitrogen is produced.
In the fourth stage, a shear reaction takes place, which takes place under different catalysts and two different temperature regimes. Initially, Fe3O4 is used, and the process proceeds at a temperature of 400 ° C.In the second stage, a more effective copper catalyst is involved, which allows the production to be carried out at low temperatures.
The next fifth stage involves getting rid of the unnecessary carbon monoxide( VI) from the gas mixture by applying an alkali solution absorption technology.
At the final stage, carbon monoxide( II) is removed by using a hydrogen-to-methane conversion reaction through a nickel catalyst and a high temperature.
The gas mixture resulting from all manipulations contains 75% hydrogen and 25% nitrogen. It is compressed under high pressure, and then it is cooled.
It is these manipulations that describe the ammonia recovery formula:
N2 + 3H2 ↔ 2 NH3 ↑ + 45.9 kJ
Although this process does not look very complicated, all of the above actions for its implementation indicate the difficulty of obtaining ammonia on an industrial scale.
The quality of the final product is affected by the absence of impurities in the raw material.
Having gone a long way from a small laboratory experience to large-scale production, obtaining ammonia today is in demand and an indispensable branch of the chemical industry. This process is constantly improved, providing quality, economy and the required quantity of product for each cell of the national economy.