RESEARCH OF TECHNOLOGY FEATURES OF SODA PRODUCTION

Аннотация

The basic block diagram of the technological process of soda production is analyzed. The functional scheme of carbonation and absorption columns and the properties of the liquid and gas phases in the production of soda have been studied. Functional relationships between the parameters of absorption and carbonation processes were considered as an object of mathematical modeling. Keywords: absorption, carbonation column, pressure, concentration, flow rate. It is one of the most important products of the basic chemical industry. Soda ash is widely used in many industries, as well as for household needs. The main raw materials for the production of soda ash are sodium chloride (salt) and calcium carbonate (limestone). On the territory of Uzbekistan, there are all the main types of raw materials for its production [1-3]. One of the typical modeling objects is the technological scheme of soda ash production (Fig. 1). The functioning of the technological scheme of soda production is carried out as follows. An aqueous solution of table salt, previously purified from calcium and magnesium salts, enters the brine purification section 1. In the absorption section 3, the purified brine is absorbed by ammonia and partially by carbon dioxide. Part of the ammonia lost during production is replaced by gaseous ammonia. The ammoniated brine is pumped 4 to the carbonization section 5. Here the ammoniated brine is saturated with carbon dioxide supplied by compressors from the compression section 10, resulting in the formation of sodium bicarbonate. 157 ACADEMIC RESEARCH IN MODERN SCIENCE International scientific-online conference NH 3 NaCl 3 2 4 6 5 7 1 NH 3 +CO 2 10 CO 2 NH +CO 3 2 CaCO 3 12 11 13 8 9 CaCl и др. 2 отходы Fig. 1. Technological scheme of the production of soda ash. 1-brine cleaning, 2,4,12-pumps, 3-absorption department, 5-carbonization department, 6 filtration, 7-calcination department, 8 - roasting department, 9 quenching department, 10-compression department, 11-distillation, 13 - department of heavy soda. The precipitated sodium bicarbonate is separated from the liquid using a drum vacuum filter in the filtration section 6. The filtered liquids are sent to the distillation section 11 by pumps 12, and the sodium bicarbonate is fed into the calcination section [2,3]. In calcination section 7, wet sodium bicarbonate decomposes when heated in calciners to form light soda ash. Light soda ash has poor thermal conductivity and occupies a large volume. To change the crystal structure in industry, the method of recrystallization of soda ash in solution is used. At the same time, soda with a large bulk mass is obtained, heavy soda ash, in the department of heavy soda 13. In the distillation department, ammonia is regenerated from the ammonium salts contained in the liquid filtered from the precipitate of sodium bicarbonate. To do this, the filter fluid is treated with steam and lime milk. The separated ammonia is returned to absorption section 3. According to [4], each compartment consists of several complexes, in turn, the complexes consist of several apparatuses and devices in which various physical and chemical processes occur (kinetic, heat and mass transfer, hydrodynamic, and others). 158 ACADEMIC RESEARCH IN MODERN SCIENCE International scientific-online conference For the purpose of analysis, we present the structure of physicochemical processes and their interaction in the following form (Fig. 2). On fig. 2 table salt (TS), heavy soda ash (SA), limestone (L), CaCl and other wastes 2 (W), at intermediate stages, individual intermediates Р(I = 1,2,…,15). i J (I = 1,2,…,10) departments in which technological processes take place (devices, i devices), F( I = 1,2,…,10) – control actions. i P F P F P F P F P F P F P 1 1 2 2 3 3 4 4 5 5 6 6 15 TS J 1 J 2 J 3 J 4 J 5 J 6 SA P 14 P 11 P 12 J 10 P 13 F 10 L J 7 J 8 J 9 W P 7 F 7 P 8 F 8 P 9 F 9 P 10 Fig 2. The structure of physical and chemical processes and their interaction. It has been established that the main processes for the production of soda ash are the separations of absorption and carbonization. Therefore, we will further consider the main devices of these departments, the tasks of their automation, as well as approaches to the mathematical modeling of such processes. The absorption section uses bubbling and scrubber type devices to absorb NH 3 and СО . Modern and newly built soda plants are equipped with bubbling-type 2 apparatuses with a counter flow of gas and liquid. Bubbling apparatuses are vertical columns consisting of a number of barrels connected by rubber gaskets and bolted together. Each bubbling barrel has a special device - a bubbling plate, on which there is close contact between gas and liquid. The apparatus has several such plates sandwiched between flanges. When gas passes through the brine layer, foaming of the liquid occurs, which contributes to better contact between the gas and liquid phases. To reduce equipment corrosion, sulfides are i