The most widely used inorganic acids are sulfuric, nitric and hydrochloric. Of these, sulfuric holds a special place. In terms of production and scope, it is one of the first places among the products of the chemical industry.

Sulfuric acid used in a variety of industries. She is one of the main products, determining the development of the chemical industry, that is why it is often called “bread chemistry”.

In the chemical industry sulfuric acid is used for the production of fertilizers, obtain dyes, plastics, chemical fibers, in the production of petroleum — based liquid fuels, lubricating oils, etc. In metallurgy sulfuric acid is used in the separation of metals from ores, engineering at etching, in the food industry for molasses, starch, alcohol, in textile — in the bleaching of fabrics, etc.

The chemical composition of sulfuric acid is a compound of sulphuric anhydride SO₃ water. When "volume if one mole of sulfuric anhydride account for the mole of water, the resulting anhydrous sulfuric acid N₂ЅO₄.If the ratio SO₃ : N₂In < 1, a diluted sulfuric acid, if the ratio SO₃ : N₂In > 1, then the solution of sulfuric anhydride in sulfuric acid, called oleum: In industry, sulfuric acid is produced in the form of a diluted, concentrated oleum and.

Appearance sulfuric acid is a colorless malopodvalna liquid with a specific gravity of 1,84 kg/cm. The starting material in the preparation of sulfur dioxide is SO₂, formed during the firing of various sulfur-containing products.

Great importance has the use of waste gases of nonferrous metallurgy, resulting from the processing of sulphide ores, as a feedstock for sulfuric acid, reducing the CE cost, and disposal gives them the opportunity to improve working conditions in metallurgical plants.

Sulfur dioxide can also be prepared from hydrogen sulfide. The last considerable amounts of gases released from the petroleum refining industry. The best raw material for the production SO₂ is elemental sulfur. When burnt, generates pure concentrated sulfur dioxide, not contaminated with impurities, for easy cleaning in the manufacture of sulfuric acid. However, pure sulfur is too expensive raw materials, whereby the cost of sulphuric acid" and the resulting" sulfur, twice the cost of N₂ЅO₄, extracted from the pyrites FeSО₂.

Currently in the industry sulphuric acid is obtained in two ways — nitrous and contact. In both cases the essence of the process is reduced to the oxidation of sulfur dioxide SO₂ sulphur SO₃and combination of the trioxide with water.

Under normal conditions sulfur dioxide by oxygen of the air does not oxidize, therefore, the oxidation process is carried out either with nitrogen, or in the presence of a solid catalyst. Method of oxidation and identifies the technology process. In the way that nitrous dioxide is oxidized to SO₃ using nitrous mixture, consisting of oxide and nitrogen dioxide, in the ratio 1:1. The contact method consists in the oxidation of the dioxide in the presence of a solid catalyst.

Older is the nitrous method of production of sulfuric acid. Nitrous method is difficult to automate. In addition, the resulting acid has a concentration of not more than 75 -77% and contaminated with impurities. These shortcomings led to, what nitrous method of production of sulfuric acid is increasingly losing its value, and the preferential development receives contact method.

Technology contact process involves the oxidation of sulfur dioxide in the presence of solid catalysts. To.20-30-ies of the catalyst used platinum. It was then replaced by much cheaper stable catalyst, manufactured from vanadium pentoxide Y₂O₅.

When the contact method of production can be polucheny sulphuric acid of practically any concentration and high purity. This sulfuric acid can be used in any production.

Nitrous acid, produced by obsolete technology, used in the production of agricultural fertilizers., which do not require high concentration and purity of raw products.

Nitric acid value and total production ranks second after sulfuric. It is widely used in the production of fertilizers, explosives, rocket fuel, synthetic dyes, plastics, nitrocellulose, synthetic fibers, etc. In appearance nitric acid is a colorless heavy liquid with a specific gravity of 1,52 g/cm⁸, its chemical composition is expressed by the formula HNO₃.

Industrial production of nitric acid is the oxidation of synthetic ammonia. The process is carried out in three stages: 1) the oxidation of ammonia by atmospheric oxygen to nitric oxide in the presence of a catalyst (platinum and its alloys); 2) the oxidation of nitrogen monoxide to dioxide; 3) absorption NO₂ with water to form nitric acid.

The oxidation of ammonia to nitric oxide proceeds at sufficient rate only at high temperatures. Possible adverse reactions, resulting in release of no nitric oxide, but free nitrogen or nitrous. To pre-to prevent these reactions, it is necessary to conduct the oxidation at temperatures no, above 700-800 °C in the presence of a catalyst. The latter is made in the form of grids of very fine wire with a diameter of 0,06— 0,09 mm.

This method of production of nitric acid allows to obtain the acid concentration -48 -t- 5,0%. To obtain a more concentrated product the process is carried out, at elevated pressures. The application of pressure to 10 the ATA allows you to increase the concentration of nitric acid up to 60-62%.

Currently in production are three technological scheme for producing nitric acid: I) under atmospheric pressure; 2) under pressure to 10 at; 3) combined.

Scheme under pressure does not differ in principle from the circuit under atmospheric pressure, but the amount of oxidation and absorption of the devices is much less. The process of oxidation of nitrogen oxide to dioxide proceeds much faster and increases the degree of absorption of oxides" water, However if you increase the pressure in the ammonia oxidation process increases the loss of expensive catalyst, what is the downside of this scheme.

The combined method allows to use advantages of both schemes. When the oxidation of ammonia is carried out at atmospheric pressure, which drastically reduces the loss of platinum, and the oxidation of nitrous gases to dioxide and absorbance they are under pressure. This allows us to obtain the acid concentration 60 — 62%. The combined method used pressures up to 4 — 9 at.

Concentrated nitric acid is, containing 97 — 98% HNO₃, obtained by evaporation of dilute nitric acid in the presence of sulfuric acid, absorbing water. It is also used to direct the synthesis of concentrated HNO₃. In this case, the nitrogen dioxide is cooled to — 8 °C. It is liquefied with the formation of the dimer N₂O₄. The latter is fed into the apparatus, where under pressure 50 at and the temperature 75 °C in the presence of water and oxygen is formed concentrated nitric acid:

2 N₂O₄ + 2 H₂O + O₂ = 4 HNO₃

The scale of production of hydrochloric acid compared with sulfuric and nitric. It is used in the production of various chloride salts, during hydrolysis of cellulose, when etching metals, when soldering, tinning, etc.

Hydrochloric acid is a solution of hydrogen chloride in water. HC1 hydrogen chloride is a colorless gas with a pungent odor, soluble in water. In industry it can be obtained in two ways: direct synthesis of H₂ and CI₂ and in the chlorination of organic compounds.

Most popular in the industry received a direct method of synthesis of hydrogen chloride from gaseous chlorine and hydrogen, obtained by electrolysis of solutions of common salt.

The reaction between chlorine and hydrogen CI₂ + H₂ = 2HCI occurs only in the light and if heated. It refers to the type of chain and can cause an explosion, if you mix large amounts of the starting components. Steady flow of reactions is the continuous flow of jet gases in a zone of high temperature (to 2400 °C). The process is conducted in special furnaces with air cooling go water.

A large amount of hydrogen chloride formed in the process of synthesis of organic compounds, for example, in the chlorination of benzene to produce chlorobenzene: C₆H₆ + C1₂ = C₆H₅CI + HCI.

To characterize the efficiency of processes in the chemical industry use a number of indicators:

• the degree of transformation X -- index, characterizing the completeness of the use of feedstock and the degree of its transformation into a finished product, which is calculated by the formula:

,

where P is the number taken in the process of the original product; P₀ — the amount of this product, reacted during the chemical process;

• the output of product f is the ratio of the amount of substance P to the maximum possible P _mOh calculated according to the chemical equation:

· performance P, ie. the amount of product, produced per unit of time:

, where L is the number of generated product; T — time;

• intensity U is the performance, related to the volume or cross-sectional area of the device:

or

where P — performance; S — sectional area of the device; V—volume of the device.

• the cost of production: and) shop; b) production; in) full.

Shop cost represents the cost of the shop, associated with production. Production cost in addition to the costs of the workshops include plant-wide costs. The total cost consists of production costs and nonproduction costs, includes mainly costs, associated with the sale of products.

When calculating the cost of production takes into account the cost: 1) raw, basic materials, purchased products and semi-finished products; 2) auxiliary materials; 3) fuel; 4) energy; 5 ) depreciation of fixed assets; 6) basic and additional wages; 7) deductions for social insurance; 8) General plant costs. Most of the expenditures in this case, as a rule, fall on raw. The average for the chemical industry raw material costs make up 60-70% of the cost, but fuel and energy — about