RU2775976C1 - Method for producing steel, electricity, and portland cement - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to ferrous metallurgy, power engineering, and cement production and can be used for producing steel, electricity, and Portland cement within the framework of a single power engineering complex. Steel undergoes liquid-phase reduction of cast iron, oxidative refining, and deoxidative alloying in a melting drum chamber. The forming slag melts are saturated with lime in the saturation drum chamber, and cooling of cement clinker and purification of the cement from metal inclusions are performed outside of the process chambers. Liquid phase reduction of cast iron is herein performed in the course of the recovery stage of melting, and the number of recovery melting operations within the stage is determined based on the volume of cast iron collected into the chamber. Electricity is produced at a thermal power plant included in the complex. The dust and gas mixture released from the melting chamber is after-burned in the burner of the boiler of the thermal power plant, using the corresponding burner mode of the boiler for each melting period in the melting drum chamber. The slag melt and carry-over ash formed at the thermal power plant are used in the recovery stages of melting. The dust and gas phase released from the saturation drum chamber and the clinker refrigerator is used as a heat carrier when firing lime.

EFFECT: possibility of producing a wide range of products within a single production complex.

9 cl, 36 tbl, 6 ex, 2 dwg

Description

The invention relates to ferrous metallurgy, energy and cement production. The method can be used to produce: steel, electricity and Portland cement within a single energy technology complex (ETC). When implementing the method, together with primary sources of raw materials and energy such as: iron ore, coal, limestone, electricity, natural gas, etc., secondary material and energy resources (SMR and VER) are used, such as: hot furnace gases, slag melts, substandard iron-carbon alloys, dump slags, scrap metal, gas cleaning system dusts, coal-fired energy waste, products of cryogenic air rectification, etc.

A known method of producing steel, including the production of iron in a blast furnace [1. Vegman E.F., Zherebin B.N., Pokhvisnev A.N., Yusfin Yu.S., Kurunov I.F., Parenkov A.E., Chernousov P.I. Iron metallurgy: textbook for universities. 3rd ed., revised. and additional / Edited by Yusfin Yu.S. - M.: IKTs "Akademkniga", 2004. -774 p.], oxidative refining of metal in an oxygen converter and deoxidation-alloying of steel in a ladle-furnace unit (AKP) [2. Bigeev A.M., Bigeev V.A. Steel metallurgy: 3rd ed., revised. and additional - Magnitogorsk: MSTU, 2000. - 542 p.]. When implementing this method, VER - combustible gases (coke oven and blast furnace) are used in the production of electricity, and VMP - granulated blast-furnace slag is used in the production of Portland cement. This method has the following disadvantages: firstly, due to the large distance of the thermal power plant and cement production from sources of secondary resources, part of the energy resources (physical heat) is lost; secondly, this method does not allow processing steel-smelting slags and energy production waste into cement.

Known device "roll-camera for the implementation of thermochemical processes” [3. EN 2692532 C1, 2018], which is used for hardware design of various technological processes. The roll-camera has a body, which is a hollow roller with a symmetrical cylindrical-conical surface with a larger diameter in the central zone along its length. The inner working surface of the body is lined. The roll is installed with the possibility of rotation around a horizontal axis. On both sides, non-rotating inserts are introduced into it, in which inlet channels are formed, ensuring the supply of materials and gas mixtures to the chamber and an outlet channel, through which the resulting dust-gas mixture is removed from the chamber. In addition, video cameras and devices are placed on non-rotating inserts, which make it possible to control the processes in the chamber and channels of the inserts. Each insert is installed with the formation of a gap between the inner surface of the housing and the outer surface of the insert. The slot is used as a channel for supplying gas mixtures to the roll chamber. The inserts are made with the possibility of their removal from the chamber, and sealing cuffs are installed at the contact points of the inserts with the rotating body. A loading hatch is installed in the central part of the chamber body. In particular cases of execution, a sliding gate is installed in the central part of the body for discharging liquid products of melting and a sampling mechanism, and burners for burning additional fuel are installed on non-rotating inserts. In addition, a system of shutters is installed in the outlet channel of the roller chamber, which makes it possible to regulate the logistics of the outgoing dust-gas mixture.

The closest in technical essence and the achieved effect is the method of obtaining steel and Portland cement [4. RU 2710088 C1, 2017]. The method uses rotating technological chambers: a melting chamber and a saturation chamber. Cameras are analogous to a roll-camera [3. RU 2692532 C1, 2018]. In the melting chamber, the main technological operations associated with the production of steel are carried out, namely: liquid-phase reduction of cast iron, oxidative refining and deoxidation-alloying of steel. In the saturation chamber, Portland cement clinker is obtained. Clinker is obtained by saturating slag melts formed in the melting chamber with lime. The clinker is cooled in a clinker cooler. In accordance with the task, a Portland cement mixture is formed, which includes clinker and technological additives [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.] and [6. GOST 30515-2013 Cements. General specifications. - M.: "Standartinform", 2014. - 41 p.]. Cleaning of Portland cement mixture from metal inclusions is carried out in the process of grinding and air separation. This method has the following disadvantages. First, the method does not provide for the production of electricity. Secondly, the method does not provide for the production of lime, which is an important raw material component, both in the production of steel and in the production of Portland cement.

The objective of the invention is to propose a method for the production of steel, electricity and Portland cement within a single energy technology complex (ETC). In this complex, the energy subsystem should produce electricity, and the technological subsystem should produce steel and Portland cement. In this case, the energy subsystem will process the SER and SMR formed in the technological subsystem, and the technological subsystem will process the SER and SMR generated in the energy subsystem. Such an interaction of material and energy flows within the framework of a single ETC will open up wide opportunities for reducing energy costs in these industries and, if necessary, will make it possible to carry out their carbon neutralization, that is, to stop the emission of CO ₂ into the atmosphere.

The problem is solved by the claimed method of production of steel, electricity and Portland cement. In the proposed method, steel, electricity and Portland cement are produced within the same ETC. The method uses technological chambers proposed in the prototype [4. RU 2710088 C1, 2017]. According to the method, the liquid-phase reduction of cast iron is carried out in the process of the reduction stage of melting, which includes at least one liquid-phase reduction melting. The number of such melts in the stage is determined based on the volume of cast iron collected in the melting roll-chamber before oxidative refining. Electricity is produced at a thermal power plant by burning fuel, producing a radiating gaseous body, transferring thermal energy from the gaseous body to water, generating water vapor, and converting steam energy into electrical energy. Moreover, the dust-gas phase from the melting roll-chamber is burnt out in the boiler furnace of a thermal power plant. Combustion of fuel is carried out in accordance with the combustion mode of the boiler, providing a given mode of operation of the turbine of the electric generator, during the metallurgical cycle of the melting roll-chamber. At the same time, the combustion mode of the boiler determines the consumption of the main fuel - the dust-gas phase from the melting roll-chamber, additional fuel and oxidizer. Slag melt and fly ash from a thermal power plant are used in reduction smelting, and the dust-gas mixture leaving the saturation roll-chamber and clinker cooler is used as a heat carrier during lime roasting, which is used in the method, to saturate slag melts and as a flux in production. become. All gas mixtures formed during the implementation of the method after their use are dedusted and subjected to desulfurization, and the gypsum obtained in the process of desulfurization is used as a technological additive in the formation of the Portland cement mixture.

In particular cases of the implementation of the method at the reduction stage of melting, scrap metal is introduced into the melting roll chamber. Scrap metal fraction (0-50) mm is introduced in the solid state immediately into the roll-chamber. Large scrap is first melted under a layer of melted slag coming from a thermal power plant, and then it is poured into a melting roll chamber, along with slag. When melting scrap metal with a high copper content, sulfur is added to the metal.

In particular cases of the implementation of the method, molten iron slags and iron-carbon alloys are used as a reaction medium for the liquid-phase reduction of cast iron.

In particular cases of the implementation of the method, raw materials coming for processing from a technogenic dump (dump) are prepared and introduced into the melting roll chamber at the reduction stage of melting. In the process of preparation, the waste slag is crushed, separated from metal inclusions, dried and its chemical composition is averaged. At the same time, waste slag is introduced into the technological process as part of the charge mixture, and metal - together with scrap metal.

In particular cases of the implementation of the method, in order to optimize the temperature of the radiating gaseous body, a coolant gas is introduced into it, in addition, corrective additives are introduced into the slag melt formed in the boiler furnace of a thermal power plant to optimize its chemical composition and viscosity, while the flow rate of the coolant gas and corrective additives are determined by the furnace mode of the boiler, ensuring the specified mode of operation of the turbine of the electric generator, during the metallurgical cycle.

In particular cases of the implementation of the method, the molten slag remaining in the melting roll chamber after the steel is tapped is subjected to corrective reduction melting. As a result, a corrected slag melt is obtained, which is used in the method in the production of cement.

In particular cases of the implementation of the method when burning fuel at a thermal power plant, a complex oxidizer is used, including oxygen and a gaseous body filler. At the same time, oxygen is introduced in proportion to the organic component of the fuel, ensuring the required completeness of its combustion, and the flow rate, composition and temperature of the filler are regulated in such a way as to form, during the combustion process, a radiating gaseous body capable of providing the required mode of water evaporation and steam production with specified parameters.

In particular cases of the implementation of the method, the resulting gas mixtures, after dedusting and desulfurization, are used in the formation of a gas body filler. To do this, excess nitrogen is removed from them and the missing water (in the form of steam) is introduced.

In particular cases of the implementation of the method, part of the gas mixtures formed at a thermal power plant, after dedusting and desulfurization, is subjected to cryogenic cleaning to obtain dry ice. One part of the resulting ice is subjected to sublimation and used in the preparation of a gas body filler, and the other part is sent to consumers or accumulated in storage facilities. To cool the gas mixtures to be cleaned, the products of cryogenic air rectification and the sublimated part of the ice are used, and the power of the thermal power plant is selected in such a way as to minimize the energy costs associated with the production of dry ice.

Since all physico-chemical processes associated with the production of steel in the proposed method are sequentially carried out in one volume (roll-melting chamber). For an outside observer, the entire metallurgical cycle of steel production here will represent one heat. Such melting will include a reduction step, an oxidizing step, and deoxidation-doping.

In the process under consideration, the melt reduction step may include one or more liquid phase reduction melts. Each liquid-phase melting, as a rule, is carried out until the maximum allowable volume of melt (cast iron and slag) is collected in the melting roll-chamber. After the release of excess slag, the next melting is carried out, filling the melting roll-chamber with metal. The number of heats is determined based on the given volume of cast iron. At the same time, for each reduction heat, their own material and heat balance is calculated. Roll-melting chamber (CM) can be attributed to semi-batch chemical reactors, in which one part of the product is accumulated, and the other part, the gas phase, is continuously discharged. Since the gas is removed in real time, the parameters of the gas flow are an important information channel that allows you to control the processes in the CP and in the furnace of the TPP boiler, where the dust-gas mixture is removed. Thus, the temperature and chemical composition of the outgoing gas phase makes it possible to evaluate the energy of the process in the CP, and the change in its consumption - to evaluate the intensity of reduction processes (FeO + C = Fe + CO) in the chamber and clarify the consumption of materials introduced into the furnace of the TPP boiler. Figure 1 shows a graph of changes in the gas flow rate in the discharge channel of the KP during the reduction melting, from the start of the input of charge materials to the release of excess slag. The graph is a trapezoid ABCD. τ ₂ - time of supply of charge materials, s. The angle of inclination of the side AB characterizes the rate of increase in gas consumption as charge materials are introduced into the chamber, and τ ₁ is the time it takes to reach the normal melting mode, s. ВС= τ ₃ - operating time in normal melting mode, s. It is defined as the difference τ ₂ -τ ₁ . The height of the trapezoid q _g - second gas flow through the discharge channel in the normal mode of melting, m ³ / s. This flow rate is constant, since in the normal mode, the coal particles that have exhausted their resource are replaced by newly introduced into the chamber. The angle of inclination of the CD side characterizes the decay rate of the recovery processes in the chamber after the supply of charge materials is stopped, and τ ₄ is the decay time of the process, s. If during the melting process the fractional and grade composition of the reducing agent does not change, then τ ₁ =τ ₄ and the trapezoid ABCD is isosceles. The base of the trapezoid AD=τ ₅ =τ ₂ +τ ₁ is the total melting time, s, from the start of the material supply to the release of excess slag. The area of the trapezoid is equal to the gas flow rate through the discharge channel for melting V _g , m ³ . Gas consumption is determined from the material balance.

The oxidizing stage of melting includes particular physical and chemical processes associated with the oxidation of harmful impurities and excess carbon. Since the main process for removing impurities at this stage is oxidation, the stage is called oxidative refining.

The use in the claims of the technological stage "deoxidation-doping" instead of "deoxidation" and "alloying" is due to the fact that the additives introduced at this stage are often both deoxidizing and alloying. The detailed name of the smelting stage is used in the special literature (see [2. Bigeev A.M., Bigeev V.A. Metallurgy of steel: 3rd ed., revised and additional - Magnitogorsk: MSTU, 2000. -542 p. ], page 22).

In the process of deoxidation-alloying of steel, hydrogen, oxygen, nitrogen are removed from it and alloying elements are added. The use of a ROL-chamber made in a single housing in the method under consideration makes it possible to create a vacuum in it or fill it with an inert gas. At the same time, the creation of a special atmosphere here can be combined with intensive mixing of metal and slag during the rotation of the chamber. This greatly improves the efficiency of the traditional physico-chemical processes used in this smelting step.

In the method under consideration, electricity is obtained at a steam turbine thermal power plant (TPP), which includes a boiler unit (boiler), a steam turbine (turbine) and an electric generator. Fuel is burned in the boiler furnace, producing a radiating gaseous body. Further, in the gas ducts of the boiler, thermal energy is transferred from the gas body to water with the production of steam. In the TPP turbine, the steam energy is converted into mechanical energy, which, in turn, is converted into electrical energy by the generator.

In the method under consideration, the dust-gas phase formed during the metallurgical cycle in the roll melting chamber is used as the main fuel in the production of steam for the turbine of an electric generator. The flow rate, temperature and chemical composition of the dust-gas phase from the CP during the cycle changes. In order, under these conditions, to ensure the specified operation parameters of the turbine of the electric generator, additional fuel is introduced into the boiler furnace. In this case, the oxidizer supplied to the furnace must ensure the required completeness of combustion, both of the main fuel (dust-gas phase) and of the additional one. In the method under consideration, the consumption of components introduced into the furnace is carried out in accordance with the combustion mode of the boiler (TRK). TRK is a calculated system of consumption of components introduced into the furnace of a TPP boiler to ensure the specified operation of a steam turbine. The calculation of the fuel dispenser is carried out in accordance with the initial parameters of the components. Usually, such parameters of the components as chemical composition, temperature, pressure, etc. are used in the calculation.

In particular cases of the implementation of the method by the combustion mode of the boiler, the flow rate, composition and temperature of the gas-cooler are determined. Afterburning in the boiler furnace of hot gases from the melting chamber leads to an excessive increase in the temperature of the gases leaving the boiler furnace. In this regard, in order to optimize the temperature regime of the radiating gaseous body, gas is introduced into the boiler furnace - coolant. Usually shop air or a filler of a gaseous body (triatomic gases) is used as a coolant. The introduction of a coolant gas makes it possible to keep the temperature of the exhaust gases from the furnace at a level that is comfortable for the radiation chamber of the boiler. When calculating the fuel dispenser with a gas-cooler, its chemical composition and temperature are taken into account.

In particular cases of the implementation of the method by the combustion mode of the boiler, the consumption of corrective additives is determined. In the method under consideration, TPP boilers with liquid ash removal are used. In this case, the slag is not removed immediately, but accumulated to a certain volume. After release, the melted slag is first involved in the production of iron, and then, in the production of cement. In this regard, in particular cases of implementing the method, additives are introduced into the boiler furnace that correct the content in the slag melt: CaO, FeO, SiO ₂ Al ₂ O ₃ . This allows, on the one hand, to optimize the viscosity of the slag melt in the boiler storage tank, and, on the other hand, to obtain the required chemical composition of the melt for subsequent processing. Lime is most often used as a corrective additive. The introduction of corrective additives reduces the efficiency of a thermal power plant, but increases the energy efficiency of metallurgical and cement production.

In order to link the furnace mode of the boiler to a specific stage of melting in the melting roll-chamber (CP), its encoding is performed. In the method under consideration, the following notation for the fuel dispenser is used. TRK-1 at the reduction stage of melting, TRK-2 at the oxidative stage of melting and TRK-3 - during autonomous operation of the boiler, that is, when the boiler furnace is separated from the melting roll chamber by a sluice gate and the boiler operates only on auxiliary (additional) fuel. During this period, steel deoxidation-alloying, its treatment with vacuum or inert gas, the release of smelting products, filling the roll chamber, pouring the melt, etc. are carried out in the KP. Not all of the listed operations are carried out with a fully closed sluice gate, but in the examples below, all of the listed operations (for simplicity of presentation) are referred to as TRK-3. With more accurate technological calculations, TRK-1, TRK-2 and TRK-3 are specified, dividing into several modes. So TRK-1 is divided according to the number of reduction heats. Thus, receive: TRK1-1, TRK1-2, TRK1-3, etc. At the same time, all these modes use the VER, which comes from the KP, during the period when the melting takes place in the normal mode (see Fig.1). If the reduction melting in the CP is not yet (already) in the normal mode, then they use: TRK1-0 - with a dust-gas phase (VER), when the melting has not yet reached the normal mode or the reduction process is dying out, but the sluice gate is not yet closed. TRC-2 is also divided into several modes: TRC2-1 - when impurities are oxidized in the CP (metal dephosphorization), TRC2-2 - when excess carbon is oxidized by blast in the CP; TRK2-3 - when carbon is oxidized with iron ore or steel is directly alloyed in the KP. TRK-3 with a more accurate calculation is divided into three modes. TRK3-1, when only the turbine of the electric generator is the consumer of steam. TRK3-2, when steam is consumed not only for the operation of the turbine, but also for the operation of the steam jet vacuum pump. TRK3-3, when steam is consumed for the turbine and for the production of thermal energy. Thus, using the fuel dispenser, the technological parameters of the TPP boiler are associated with the metallurgical cycle of the melting roll-chamber.

Coal is one of the oldest types of fuel, which until the middle of the twentieth century was the main source of energy. Today, the share of coal in world energy production is declining. This is because, unlike natural gas, it does not burn completely. In energy production, only the organic part of coal is used, while its mineral part is sent to the dump, creating environmental and, therefore, economic problems.

When coal is burned at thermal power plants, mineral components are converted into ash and slag. The slag remains in the boiler furnace, and the fly ash is retained by the aspiration system behind the boiler. At the same time, fly ash, in addition to the mineral component, contains unburned carbon, the content of which depends on the conditions of fuel combustion.

The formation of ash and slag occurs at a temperature of (1500-1800)°C. The process of converting the mineral component of coal into ash and slag includes: endothermic processes associated with the decomposition of the original minerals. With the completion of these processes, coal energy waste turns into a more valuable raw material for cement production than traditional raw materials. To further increase their attractiveness, it is necessary to preserve as much as possible the heat received by them during energy production. If the fly ash, in the process of its extraction from the gas stream, already has time to cool down, then the fuel slag is involved in production in the form of a melt with a temperature of (1400-1600) ° C. To do this, the method uses the furnaces of a TPP boiler with liquid slag removal. The melt is accumulated in the storage tank of the boiler and periodically released for processing. The composition of the slag contains a significant amount of iron (10-20)%. In order to bring the slag melt to a given clinker composition, excess components are first restored from it, and then the missing ones are added. Therefore, the slag melt formed in the accumulator of the TPP boiler is first sent to the liquid-phase reduction stage of melting, where it is used as a reaction medium (liquid phase) and as an iron-containing component, and then to saturation, where the missing lime is introduced into it.

Fly ash from thermal power plants is used as an iron-containing material, as a reducing agent and as a flux, since the ash contains: iron, carbon, and lime. In order to work out all the carbon from the ash, iron ore is additionally introduced into the charge mixture, in order to ensure melting with energy, coal is additionally introduced into the chamber, and in order to obtain a given basicity of the slag, lime is added. Usually, when processing TPP ash, the reduction stage includes one liquid-phase melt. This is due to the fact that the purpose of the process is not to restore a given volume of cast iron, but to recycle a secondary resource. As a result of reduction melting, cast iron and reduced slag are obtained. Cast iron is introduced into the CP at the reduction stage of melting, and the slag is sent for saturation. In addition to cast iron and reduced slag, in the process of processing fly ash, a dusty gas phase is obtained with a high content of sublimated components, such as: Na, K, Zn, etc. The increased content of these components is a consequence of their sublimation, first in the CP and the furnace of the TPP, and then in the CP. This dust is used as a raw material in non-ferrous metallurgy enterprises or as fertilizers in agriculture.

Portland cement clinker is produced in a saturation chamber (KN). The slag entering the saturation is formed in the melting roll-chamber during the entire metallurgical cycle. The slag is sent to the mixer, where it is accumulated and the chemical composition is averaged. The melt accumulated in the mixer is divided depending on the production need into two parts: one part is sent for granulation in order to obtain an active mineral additive for cement (AMD) [7. GOST 3476-74 Granular blast-furnace and electrothermophosphorus slags for cement production. - M .: "Standartinform", 1974. - 6 p.], and the other for saturation in order to obtain clinker.

The process of obtaining Portland cement clinker includes the following partial processes: the introduction of lime and corrective additives into the initial melt, the formation of belite and alite, the formation of fusible minerals and controlled cooling of clinker balls. All these processes, except for cooling the clinker, are carried out in a saturation roller chamber.

Metallurgical and cement production consume a significant amount of lime, which is calcined with exhaust gases from the KH and the clinker cooler.

In a particular case of implementing the method, the lime calciner includes two calcination shafts. The mines work alternately. One mine is in operation, and the other is under loading - unloading. For burning lime, the dust-gas phase is first fed into the working shaft from the clinker cooler, and then from the saturation chamber.

An important advantage of steel over other structural materials is its high degree of reuse (recycling). Scrap metal is an important raw material used in the process. Scrap metal is introduced at the recovery stage of melting. The introduction of scrap metal makes it possible to speed up the process of filling the CP with metal, which reduces the time of the recovery stage of melting. In this regard, in particular cases of using the method, scrap metal is introduced to control the duration of the metallurgical cycle in order to plan the operation of the casting and rolling production site.

Small scrap metal (0-50) mm is introduced directly into the melting chamber through a loading hatch or through a channel located in the supply insert and designed for supplying ferroalloys. At the same time, the size of the maximum and minimum piece of scrap metal introduced directly into the CP depends on the method of loading and the design of the channel. The loading of scrap metal through the ferroalloy channel is carried out during the entire reduction stage of melting. Feeding is carried out with a small flow rate, so as not to supercool the bath. Thermal balancing of the process is carried out by post-combustion of exhaust gases above the bath, and in case of their deficiency, additional fuel is used.

Large scrap is pre-melted using arc steel-smelting furnaces (EAF), ladle-furnace units (LAF), etc. for this purpose.

In particular cases of the implementation of the method in the process of melting scrap, the following are introduced into the charge: coal, flux, iron-containing materials. At this stage, pig iron from the processing of fly ash and melted slag from the storage tank of the TPP boiler are involved in the technological process. The introduction of these components makes it possible to reduce the consumption of electricity and electrodes at the stage of melting scrap metal. The molten metal is introduced into the melting chamber at the reduction stage of melting together with the slag located in the melting unit.

In particular cases of the implementation of the method for removing copper from metal, in the process of melting scrap, sulfur is introduced into the metal. This allows copper to be converted into sulfide 2[Cu]+(FeS)=[Fe]+(Cu ₂ S). The sulfur (FeS) remaining in the metal is converted into slag at the reduction stage of melting. The proposed method has good potential for desulfurization of this metal. First, melting is carried out at an increased basicity of the slag. Secondly, the rotating ROL-camera ensures high efficiency of refining processes. Thirdly, the recovery stage includes several heats, that is, the highly basic slag is changed several times in the chamber. At the same time, the used slag is not sent to the dump, but is processed into Portland cement. Thus, the method allows to solve the problem of copper in steel.

In particular cases of the implementation of the method, in the liquid-phase reduction of cast iron, melts of ferrous slags of metallurgical origin, substandard iron-carbon alloys are used. The use of additional iron-containing and carbon-containing materials in the process of liquid-phase reduction increases the efficiency of metallurgical production and, in parallel, allows solving the problem of waste processing.

In particular cases, the implementation of the method is used for processing man-made waste disposal sites (dumps) of metallurgical production. The composition of non-metallic waste from steelmaking includes: slag obtained as a result of oxidative refining of steel (converter slag or slag with EAF), slag with ACP, gas cleaning system dust (GSS), scale, fireclay cullet, magnesite cullet, etc. For simplicity of presentation, the listed waste sent to the dump will be called "Dump slag".

In addition to non-metal waste, metal also enters the dump. The metal is represented mainly by additives carried away from metallurgical furnaces (splashes, pellets, etc.).

Thus, the dump of steelmaking is a technogenic burial containing (15-20)% metallic iron, (25-35)% iron in oxides and (25-35)% lime in minerals. Obviously, this raw material has too low an iron content to be considered a quality raw material for traditional steelmaking and, conversely, has a lot of iron to be considered a good raw material for cement production.

The material coming from the dump is prepared for reduction melting. In the process of preparation, the non-metallic component of the slag-metal mixture is gradually converted into dust and removed by a controlled air flow. Before the next stage of grinding, the material is subjected to magnetic separation. For grinding the material, traditional crushing and grinding equipment is used, and for dedusting, traditional dedusting devices and air separators are used. At the same time, in the process of air separation, the product purified from metal is dried. The prepared waste slag is accumulated and its chemical composition is averaged.

The products obtained during the preparation are introduced into the technological process at the reduction stage of melting. Waste slag is introduced into the melting chamber as part of the charge mixture, and the metal is introduced together with scrap metal.

In particular cases of the implementation of the method, the slag melt directed to saturation may contain excess components that reduce the quality of the resulting product (Portland cement or active mineral additive). To obtain a given chemical composition of the slag melt, corrective reduction melting is carried out. Melting is carried out in a melting roll-chamber after the release of refined steel. Deoxidation-alloying of steel, in this case, is carried out outside the technological chamber in a pouring ladle, in automatic transmission or other metallurgical production, where it is finished. As a result of corrective reduction melting, a metal alloy is obtained, into which excess components and corrected slag melt pass. The metal alloy is sent to metallurgical production, and the corrected molten slag is used in the process for the production of Portland cement.

In particular cases of the implementation of the method, when the organic component of the main and additional fuel is burned in a TPP boiler, a complex oxidizer is used, which includes oxygen and a gas body filler. Thus, in the combustion mode of the boiler (TRK), along with oxygen, another component appears - the filler of the gaseous body.

Under oxygen, in this method, should be understood as technical oxygen containing at least 95% O ₂ . Combustion of fuel in oxygen makes it possible to exclude ballast (not participating in heat exchange by radiation) N ₂ from the resulting gaseous body and radically solve the problem of emission of such harmful compounds as N _x O _y into the atmosphere. Oxygen is introduced into the boiler furnace in proportion to the organic component of the fuel, ensuring the required completeness of its combustion. In the method under consideration, as a rule, they do not strive for complete combustion of carbon in the fuel, since fly ash from thermal power plants is used as a carbon-containing charge component in the liquid-phase reduction of cast iron.

An important disadvantage of burning fuel in oxygen is the high combustion temperature. To keep the temperature in the furnace at a level comfortable for the boiler, a gas body filler is introduced into the complex oxidizer. The flow rate, composition and temperature of the filler are regulated in such a way as to obtain a radiating gaseous body in the process of fuel combustion, capable of providing the required mode of water evaporation and steam production with specified parameters. Sometimes the filler of the gaseous body is also introduced as a gas-cooler (see above). The introduction of the filler in two parts makes it possible to protect the mineral component of the fuel from hypothermia and thickening. In this case, the first part of the filler is introduced, as usual, together with the oxidizing agent. The consumption of this part is regulated in such a way as not to overheat or supercool the mineral component of the fuel (slag in the storage tank of the TPP boiler). The second part of the filler (gas-cooler) is introduced into the gas body at the outlet of the furnace, when the mineral component is already in the boiler storage and the temperature of the gas body no longer affects it.

It is known that triatomic gases, such as: CO ₂ , H ₂ O, etc., work well when transferring heat by radiation, it is these gases that are the main ones in the formation of the filler of a gaseous body. Thus, as a result of the use of a complex oxidizer in the boiler furnace, a radiating gaseous body is formed, which includes the primary gas - the result of the oxidation of the organic components of the fuel with oxygen and the filler of the gaseous body. This allows: firstly, to increase the efficiency of heat exchange processes in the boiler, by replacing nitrogen with triatomic gases, and secondly, it opens up wide opportunities for controlling the boiler power, which is very important in conditions of changing energy consumption. So, to reduce the steam output of the boiler, the primary gas is partially replaced by a gas body filler, and to increase the steam output, the filler is partially replaced by primary gas. This adjustment allows changing the temperature of the radiating gaseous body, keeping its volume flow unchanged, which is important for stabilizing dust removal from the low-velocity gas channels of the boiler.

In the process of fuel combustion in the TPP boiler, a gas mixture is formed, which, after dedusting and desulfurization, is released into the atmosphere. Such a mixture in the traditional oxidation of fuel with air contains approximately 70 vol.% N ₂ and only 30 vol.% CO ₂ and H ₂ O. The transition to the complex oxidizer proposed in the method makes it possible to obtain a gas containing (96-99) vol.% triatomic gases (CO ₂ and H ₂ O) and only (1-4) vol.% N ₂ . The presence of nitrogen in this gas mixture is explained by its presence in organic fuel.

The gas mixtures formed in the cement production, in the saturation roll-chamber, already contain (99-100) vol.% triatomic gases and only (0-1) vol.% N ₂ , since much less fuel is introduced into the roll-chamber. Usually, the gas from the saturation roll chamber in quantitative terms is only (1-10) wt.% of the gas from the TPP.

The composition of the resulting gas mixture formed during the production cycle will be close to the composition of gas from a thermal power plant. A gas mixture with such a content of triatomic gases can be used as a gas body filler. However, with repeated circulation of such gas, the content of nitrogen will increase in it (it is contained in the fuel), which will lead to a decrease in the efficiency of the boiler. To provide a given composition of the gas body filler, it is necessary, before each new cycle of using the gas mixture, to remove excess components (nitrogen) from it and introduce the missing ones (H ₂ O). Moisture partially turns into condensate.

Removal of excess components is carried out, for example, by adsorption or membrane methods. In this case, as a rule, only the gas coming from the thermal power plant is subjected to cleaning, and the gas from the saturation roll-chamber is used in the formation of the filler of the gas body without purification.

Lost moisture is compensated by supplying steam to the resulting mixture. This allows not only to reproduce the required composition of the gas body filler, but also to raise its temperature so as not to disturb the thermal regime of the boiler.

In particular cases of the implementation of the method, to remove excess components from the gas mixture, it is cryogenically cleaned. The essence of cleaning is the sequential desublimation and separation of the components of the gas mixture. The result is pure CO ₂ (dry ice) with a density of 1561 kg/m ³ . Figure 2 shows a schematic diagram of the preparation of NGT and cryogenic cleaning of flue gases in the framework of the ETC.

The key idea underlying the joint production of steel, electricity and cement is the mutual use of secondary resources formed here by the allied industries. During cryogenic cleaning of gas mixtures, "cold" secondary resources are used - products of cryogenic air rectification. To maximize their cooling capacity, the oxygen station produces not only liquid oxygen and liquid argon, but also liquid nitrogen.

Flue gases from thermal power plants and cement production (clean gas) are supplied for processing. They are sent, respectively, to gas holders 1 and 2. At the same time, part of the gas from the thermal power plant (gas without purification) and most of the clean gas are sent to the mixing gas holder 3, where the composition of the CNG is formed. The rest of the gas from the TPP from the gas holder 1 is sent for cryogenic cleaning (gas for cleaning).

In the process of cryogenic cleaning, two stages are distinguished: the stage of preliminary cooling of the gas mixture and the stage of phase transformation (obtaining ice). At the stage of pre-cooling, components are removed from the gas mixture that pass into another state of aggregation before CO ₂ , and at the stage of phase transformation, carbon dioxide is already separated from excess components by transferring it to a solid state (dry ice).

At the first stage of pre-cooling in the heat exchanger 4, water condensate is removed from the gas mixture. The temperature of the gas mixture in the heat exchanger 4 - T _cm ≥ 273 K. In the second stage of pre-cooling in the heat exchangers 5,6 and 7, H ₂ O and SO ₂ residues are separated as they pass into the solid phase. The temperature of the gas mixture during this period is in the range T _cm =(273-195) K. Prepared in this way, the gas mixture with a temperature of T _cm ≈195 K enters the stage of phase transformation (ice formation). At this stage, primary (liquid) products of cryogenic air rectification are used as coolants, namely: liquid nitrogen, liquid oxygen and liquid argon. The scheme for obtaining ice depends on which product of cryogenic air rectification is used as a cooler:

When using liquid nitrogen . The gas mixture to be purified is compressed in compressor 8, liquid nitrogen is introduced into it and sent to expander 9. In this case, a heterogeneous thermodynamic system “gas mixture to be purified - liquid nitrogen” is formed. The main components of this system is in the process of a phase transition. Liquid nitrogen, interacting with the components of the gas mixture being purified, heats up and passes into the gaseous state, taking the heat of the phase transition from carbon dioxide. As a result of this heat exchange, a significant part of the carbon dioxide is converted into a solid state. Since the process occurs with the formation of a new phase (dry ice), it can be considered isothermal (T=194 K). The carbon dioxide remaining in the gaseous state is converted into a solid state by performing mechanical work by the gas mixture in the expander. The work of the expander in an isothermal process is determined by the formula

, (Дж/кг) (1) L _dt =RT ln

, (J/kg) (1)

where p1 and p2 , respectively, are the initial and final pressures of the working fluid in the expander.

Thus, by compressing the gas mixture to be purified in the compressor 8, the necessary initial pressure of the working fluid is obtained, thereby ensuring the transfer of the remaining gaseous carbon dioxide into ice. The mechanical work done in the expander is converted into electrical energy, which is used within the ETC.

Thus, as a result of heat exchange and expansion of the gas mixture, the phase transition heat is removed from carbon dioxide. The resulting solid phase (dry ice) and secondary nitrogen (gas) enter the settling chamber of the expander 10, where dry ice CO ₂ is retained, and secondary nitrogen with a temperature _{of TWN} =194 K is removed. Together with the secondary nitrogen, the nitrogen and oxygen contained in the gas mixture to be purified leave the settling chamber.

When using liquid oxygen and argon . Part of the secondary nitrogen from the settling chamber 10 is cooled in recuperative heat exchangers 11 and 12. Liquid oxygen and liquid argon are used as coolants, respectively, which change their state of aggregation during heat exchange. The thus cooled secondary nitrogen, together with liquid nitrogen, is introduced into the gas mixture to be purified after the compressor 13 and sent to the expander 14. , dry ice (CO ₂ ) and new secondary nitrogen (gas) are formed. Dry ice is retained in the settling chamber of the expander 10, and secondary nitrogen with a temperature of T _WN =194 K is removed from the chamber, taking nitrogen and oxygen with it from the gas mixture being purified.

The secondary coolants (N ₂ , O ₂ and Ar) formed at the stage of phase transformation are used as coolants at the stage of pre-cooling of the gas mixture to be purified. After that, nitrogen is sent, for example, to the production of fertilizers, and oxygen and argon are used in the process. Oxygen is used as an oxidizing agent, and argon as an inert gas, in metallurgical production.

The ice obtained as a result of cryogenic cleaning enters warehouse 15. One portion of the ice to be sublimated is first sent to heat exchanger 4, where it changes its state of aggregation, cooling the gas mixture supplied for cleaning, and then to mixing gas holder 3, where NGT is formed . Another portion of ice is fed through the lock 16 into the sublimation chamber 17, where it changes its state of aggregation, cooling the water from the TPP condenser. By adjusting the supply of ice, excess pressure is created in the sublimation chamber. The pressurized gas from the chamber 17 is heated in the heat exchanger 18 and performs work by rotating the turbine of the electric generator 19. The electricity produced here is used within the framework of the ETC, and CO ₂ with a given pressure and temperature enters the mixing gas holder 3, where the gas turbine is formed.

The flow rate of gas mixtures used in the formation of NGT is regulated in such a way that the nitrogen content in the resulting composition does not exceed the permissible value. The resulting gas mixture is fed from the gas holder 3 to the TPP boiler through the mixing heater 20, where water vapor is introduced into it. The temperature and steam flow rate are regulated in such a way as to ensure the specified composition of the NGT and not disturb the temperature regime of the heater in the TPP boiler. Received as a result of cryogenic cleaning, but not used in the method of ice (CO ₂ ) is transported to the place of further processing or disposal.

An important factor determining the viability of this particular case of the implementation of the method is the energy intensity of ice production, which depends on the ratio of the energy and technological subsystems in the composition of the ETC. When the optimal ratio is reached, the energy intensity of ice production will be minimal. This ratio is unique for each specific ETC. In addition, it may vary depending on the quality of raw materials, the composition of the products produced, the technological modes of production, and so on. In this regard, at the design stage of the energy technological complex, when the conditions for its operation are determined, the power of the thermal power plant is chosen in order to bring the ratio of the energy and technological subsystems closer to the optimal value. The proportionality of these subsystems can be assessed by the consumption of oxygen in them, or, what is the same, by the energy consumption for oxygen production.

Carbon dioxide plays an important role in shaping the climate on our planet. Being in the atmosphere, it delays infrared radiation. In this regard, a decrease in the content of CO ₂ in the atmosphere leads to a decrease in the average annual temperature on the earth, and an increase leads to an increase. To maintain balance in nature, there are both sources and consumers of carbon dioxide. The largest natural producers of CO ₂ are volcanoes, and the main consumers are plants (phytoplankton, forests, etc.). Thus, on our planet there is a closed biogeochemical cycle of carbon circulation. With the beginning of the industrial revolution, man also announced himself as a major producer of CO ₂ . Thermal power, metallurgy and the cement industry are the main producers of carbon dioxide. We are currently seeing an unprecedented rise in carbon dioxide in the atmosphere. This can lead to an ecological disaster.

One of the objectives of the invention is to propose a method that allows carbon-neutralization of steel, energy and cement industries within the framework of the ETC. To solve this problem, it is necessary to separate the CO ₂ formed here and organize its transportation to the place of processing or disposal. As shown above, cryogenic sedum of the gas mixture will allow CO ₂ to be separated from flue gases and turn it into ice with a density of 1561 kg/m ³ . This density of the product makes it possible to transport it to the place of processing or disposal by conventional transport. This, in turn, opens up wide opportunities for the processing of CO ₂ by both natural and industrial consumers. It should be noted that the conversion of gaseous carbon dioxide into a solid state solves a number of problems in the geological disposal of CO ₂ .

Thus, the proposed method, in particular cases of its implementation, allows for carbon neutralization of steel, energy and cement production within the framework of the ETC.

Further, the above-mentioned essential features, advantages and benefits of the proposed method will be illustrated by examples. The given examples do not limit all possibilities of the method.

Example 1

Obtaining steel [8. GOST 1050-2013 Steel products from non-alloyed structural high-quality and special steels. General specifications. - M.: "Standartinform", 2014.- 32 p.], electricity [9. GOST32144-2013 Power quality standards in general-purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.] and Portland cement [5. GOST 31108-2016 General construction cements. Specifications. - M .: "Standartinform", 2016. - 12 p.] within the framework of the energy technology complex (ETC).

Melting roll chamber

Roll-melting chamber (CP) has a cylindrical-conical shape [3. RU2692532 C1, 2018, 4. RU2710088 C1, 2017]. The working surface of the chamber has a magnesite lining. The inner diameter of the central cylindrical part of the chamber is 3.3 m. The length of the central cylindrical part of the chamber along the lining is 5.2 m. The diameter of the necks through which the inlet and outlet inserts are inserted is 1.25 m. The outer diameter of the inserts is 1.15 m. The mass of the CP without melt is 115 tons. The allowable volume of the melt that can be in the chamber is 12.9 m ³ . On the central cylindrical part of the chamber there is a loading hatch, a sliding gate for discharging liquid melting products and a sampling mechanism. The melting chamber rotates around a horizontal axis on support rollers. The frequency of rotation of the chamber during the melting process is changed in the range (0–30) rpm. The rotation is set by four symmetrically located drives, which are synchronized during operation by hydraulic couplings. Torque from the drive is transmitted through two gears, symmetrically located relative to the center of the chamber. In the melting chamber, the reduction stage of melting, the oxidative refining of the metal and the deoxidation-alloying of the steel are carried out. Charge materials and ferroalloys are introduced into the CP through the supply insert, and the dust-gas phase is removed from the CP through the outlet insert. The discharge channel of the CP is connected through a system of gates with a boiler of a thermal power plant (TPP) and a steam jet vacuum pump. The shutter connecting (separating) the CP with the TPP furnace allows throttling the exhaust gas flow.

Recovery stage of melting

In the CP after the previous metallurgical cycle, 0.84 tons of recycled slag remains. Before the start of the reduction stage of melting, 11.67 tons of cast iron and 17.71 tons of slag are poured into the KP through the loading hatch. Cast iron and slag come from the melting unit, where, under a layer of slag from the TPP boiler, scrap is melted and the metal melt is carburized (see below). The metal-slag bath thus obtained in the CP is used as the reaction medium for the liquid-phase reduction. During the melting process, charge materials are introduced into the initial melt. The composition of charge materials includes iron-containing raw materials, reducing agent and flux. As iron-containing material, in this example, use a mixture consisting of 80% iron ore - Fe _total =58% and 20% mill scale - Fe _total =71%. Grade T coal is used as a reducing agent, and lime is used as a flux. Fractional composition of charge materials (0-5) mm. The charge mixture is fed into the CP by pneumatic transport. An oxygen-containing blast is used as a transport medium. The charge material flow rate is controlled in such a way that the gas velocity in the outlet channel of the chamber does not exceed 40 m/s, and the fictitious velocity of gases leaving the bath is in the range (0.3-1.7) m/s. In this case, the foam on the surface of the bath does not go into a spray mode, but evenly covers the entire surface of the melt. When the volume of the melt in the chamber reaches the maximum allowable value, melting is stopped. The outlet of the sliding gate is set above the level of the metal by rotating the chamber and the slag located in the gearbox is released. At the same time, 10% of the slag remains in the chamber and passes to the next reduction melt. To obtain a given volume of cast iron at the recovery stage, five liquid-phase heats are carried out. Excess slag formed in melts 1-4 is released, and the slag from the fifth melt passes to the oxidizing stage. Table 1 shows the material balance of the recovery melts and the time of supply of charge materials in the CP (see Fig.1). Table 2 shows the heat balance of the recovery stage, and Table 3 shows the indicators characterizing the energy parameters of the exhaust gases from the CP. The compositions of the products obtained during the operation of the ETC are shown in tables 8-11.

Table 1 - Material balance of recovery heats

Material balance items 1st
pl-ka 2nd
pl-ka 3rd
pl-ka 4th
pl-ka 5th
pl-ka Total
balance Material submission time, s 2230 4587 3355 2472 1765 14409 Recycled slag, t 0.84 2.54 1.91 1.42 1.05 0.84 Slag with chipboard, t 17.71 0 0 0 0 17.36 Cast iron with chipboard, t 11.67 0 0 0 0 11.66 Ore (approx. 20%, ore 80%), t 12.37 30.70 22.43 16.53 11.81 93.84 Coal grade "T", t 7.45 15.10 11.04 8.14 5.81 47.54 Flux, t 6.60 10.42 7.78 5.74 4.10 34.64 Blowing into the afterburning zone, t 8.01 16.6 12.15 8.95 6.40 52.11 Total income items: 64.65 75.36 55.31 40.78 29.17 258.35 Cast iron, t 20.90 18.46 13.49 9.94 7.10 69.89 Slag, t, including: 25.39 19.11 14.19 10.46 7.51 Slag left in the CP, t 2.54 1.91 1.42 1.05 0 Slag product, t 22.85 17.20 12.77 9.41 7.51* 69.75 Gas, t 17.84 36.67 26.83 19.77 14.12 115.23 Dust, t 0.51 1.08 0.79 0.58 0.42 3.38 Gas impurities, t 0.04 0.07 0.06 0.04 0.03 0.24 Total expense items: 64.68 75.39 55.36 40.79 29.18 258.49 Balance discrepancy, % 0.05 0.04 0.09 0.02 0.03 0.05

* - The slag passes to the oxidative melting stage.

Table 2 - Heat balance of recovery melts

Heat balance articles 1 sq. MJ/s 2 sq. MJ/s 3 sq. MJ/s 4 sq. MJ/s 5 sq. MJ/s Sum
GJ/area The heat content of the original slag 12.05 0.81 0.83 0.84 0.86 33.37 Heat content of introduced cast iron 6.74 0 0 0 0 15.03 Heat content of charge materials 0.01 0.01 0.01 0.01 0.01 0.10 Heat from gas afterburning in PC 46.64 46.97 47.03 47.02 47.02 477.24 Total: 65.44 47.79 47.87 47.87 47.89 525.75 Heat content of cast iron 12.04 5.17 5.16 5.16 5.16 67.88 Heat content of slag 16.60 6.07 6.15 6.16 6.18 85.49 Heat content of gas 18.49 18.55 18.56 18.56 18.56 188.59 Heat content of dust 0.4 0.41 0.41 0.41 0.41 4.15 Heat content of gas impurities 0.03 0.03 0.03 0.03 0.03 0.31 Heat for charge recovery 16.47 16.00 16.00 16.00 16.00 163.80 Heat to evaporate moisture 1.21 1.34 1.34 1.34 1.34 13.34 Heat loss through PC walls 0.25 0.25 0.25 0.25 0.25 2.54 Total: 65.49 47.82 47.90 47.91 47.93 526.10 Balance discrepancy, % 0.08 0.06 0.06 0.08 0.08 0.07

Table 3 - Energy parameters of exhaust gases from the CP

Name of indicator 1 sq. 2 sq. 3 sq. 4 sq. 5 sq. The degree of afterburning of CO in the mixture, % 65.88 67.24 67.35 67.34 67.34 Exhaust gas temperature, С 1650 1650 1650 1650 1650

The recovery stage of melting is carried out at a melt temperature of 1450°C. The temperature regime is regulated by means of afterburning in the gearbox, a part of the combustible gases exhausted from the bath. To do this, an oxygen-containing blast is supplied to the afterburning zone, which contains 90% technical oxygen and 10% air.

Oxidative refining of steel (oxidizing stage of melting)

Oxidative refining includes two periods: oxidative refining of steel from harmful impurities and excess carbon.

Oxidative refining of metal from impurities

Before the start of oxidative refining, 69.88 tons of pig iron with a carbon content of 4.49% and 7.51 tons of slag are located in the KP.

Before blowing, 1.95 tons of excess slag is released from the CP. In the process of blowing into the melt through the tuyere located in the feed insert enter 1179 nm ³ technical oxygen. Purge time - 550 s. In order to reduce the formation of brown smoke, lime - 0.31 t is introduced into the oxygen jet. As a result of blowing and intensive mixing of the bath, slag with a basicity of B = 2.3 is formed in the CP, into which the removed impurities pass from the metal. At the end of the oxidative refining of the metal, 68.20 tons of pig iron with a carbon content of 3.09% and 6.51 tons of slag are formed from impurities in the CP. Since a significant amount of heat is released as a result of oxidative refining, afterburning of gases leaving the bath in the CP is not performed. The degree of afterburning of CO in the exhaust gas is 1.52%, and the temperature of the gas mixture is 1630°C. Oxidative refining of metal from impurities ends with the release of slag, which contains phosphorus. At the same time, 10% of the slag, by force, remains in the melting chamber and proceeds to the next stage.

Oxidation of excess carbon

At the beginning, the oxidation of carbon is carried out by blowing. To do this, 1861 nm ³ oxygen is fed into the bath through a tuyere. To use the heat generated in the bath, slag-forming components are introduced in parallel, namely: 3.35 tons of lime and 1.98 tons of bauxite. Bauxite contains Al ₂ O ₃ - a diluting component in deoxidized slag. The basicity of the slag at this stage is B=6.6, and the ratio B/Al ₂ O ₃ =0.27. In addition, materials are introduced into the slag that will be reduced at the stage of deoxidation-alloying. In the example under consideration, 0.61 tons of manganese ore are introduced for direct alloying. After a given amount of blast has been supplied to the bath, its supply is stopped, and the oxidation of carbon continues due to the reduction of iron oxides contained in the slag. To maintain the heat balance, partial afterburning of combustible gases leaving the bath is carried out. To do this, 533 nm ³ oxygen-containing blast is fed into the afterburning zone through slots. During this melting period, 0.12 t of dust and 5.53 t of the gas phase leave the CP, in which the degree of CO afterburning is 27.0%. The temperature of the dust-gas mixture leaving the CP to the TPP furnace is 1680°C. After this period, 66.63 tons of steel with a carbon content of 0.22% and 5.92 tons of partially deoxidized slag remain in the CP.

Deoxidation-alloying of steel

The system of gates located in the discharge channel separates the CP from the TPP boiler and connects it to the steam jet vacuum pump. The TPP boiler operates in autonomous mode, providing steam only for the normal operation of the generator turbine. The steam jet vacuum pump runs on a separate power source. It reaches a residual pressure in the chamber of 100 Pa for 1139 s. In the process of evacuation, the rotation of the gearbox continues. In this case, all hydrogen and, partially, nitrogen and oxygen are removed from the steel. After reaching a predetermined residual pressure, the vacuum valve is closed. When rarefied (reducing the partial pressure of CO) in the melting chamber, conditions are created for the recovery of manganese ore from slag and vacuum-carbon deoxidation of steel. To reduce the evaporation of the metal, the melting chamber is filled with argon and the shutter connecting it to the TPP boiler is slightly opened. In order to maintain an argon atmosphere in the melting chamber, it is fed through the side slots at a low flow rate. For final deoxidation and alloying, 0.24 t of ferrosilicon and 0.01 t of aluminum are introduced into the bath.

During the entire smelting, when necessary, samples of metal and slag are taken using a sampling mechanism.

To replenish the incoming part of the heat balance and heat the metal to a given temperature, 127 m ^{3 of} natural gas and 329 Nm ^{3 of} oxygen are fed into the afterburning zone.

After carrying out all the processes associated with deoxidation-alloying, 67.13 tons of steel, the composition of which is given in Table 8, and 5.54 tons of deoxidized alumina slag remain in the CP.

To prevent the slag from entering the steel during tapping, it is thickened. Before thickening, 4.91 tons of excess slag is discharged. 0.082 tons of lime are introduced into the remaining slag. Lime is served by pneumatic transport. Argon is used as a transport. With stirring, the slag thickens, and the metal is released into the ladle. When released from the gearbox, the metal is protected from oxidation by argon.

Filling the melting chamber

Before the start of the next metallurgical cycle, the lining is inspected using video cameras located on non-rotating inserts. If foci of destruction of the lining are found, then a shotcreting mixture is applied to them. To do this, a rod with a nozzle is inserted into the CP through the feed insert and the chamber is turned with the focus of destruction towards the nozzle. After focal violations of the lining are eliminated, a dust cloud is created in the melting chamber from the materials included in the repair mixture. To do this, 0.53 tons of dry repair mixture is introduced into the chamber through a nozzle. During the rotation of the gearbox, the dust partially settles and is fixed on the lining, and partially replenishes the thickened slag in the chamber. After carrying out preventive measures, 0.84 tons of recycled slag remains in the KP, which passes to the next metallurgical cycle.

Processing of fly ash from thermal power plants

For the processing of fly ash at thermal power plants, a small melting chamber (MCC) is used, the design of which is similar to that of the MC. The inner diameter of the chamber is 2.0 m. The length of the cylindrical part of the chamber along the lining is 2.85 m. The diameter of the discharge channel is 0.44 m. The mass of the chamber without melt is 52 tons. The allowable volume of melt that can be in the chamber is 3.1 m ³ . The MCP rotates on four rollers. The MCP drive is similar to the gearbox.

Since the volume of cast iron produced does not matter during the processing of fly ash, one liquid-phase melting is carried out at the recovery stage. Fly ash and charge materials are introduced into the MCP through a feed insert. The dust-gas phase formed in the reduction melting process is discharged through the outlet insert and the hot-water boiler into the aspiration system. Dry dust collection methods are used for gas purification. The remaining SO ₂ in the gas phase is extracted by the lime method, obtaining gypsum, which is used in the production of cement.

0.69 t of slag remains in the MCP after the previous metallurgical cycle. Charge materials are fed into the rotating chamber through the feed insert by pneumatic transport. The composition of charge materials includes 2.86 tons of fly ash, 0.27 tons of coal, 1.78 tons of iron-containing materials, and 0.66 tons of lime. The charge material supply time is 1610 s (see Fig.1). For afterburning combustible gases formed in the MCP, oxygen-containing blast is injected through the slots in the amount of 984 nm ³ . Melting is carried out at a melt temperature of 1450°C. In the process of melting, 3.44 tons of pig iron are obtained. At the same time, 0.69 tons of slag is left in the MCP, and excess slag - 2.75 tons is sent to the mixer, where slag is collected and averaged for cement production. In addition, 2.69 tons of gas goes from the MCP to the aspiration system. The degree of afterburning of CO in the gas mixture is 99.9%. Together with gas, 0.26 t of dust and 0.08 t of gas impurities leave the CP. The temperature of the dust-gas mixture is 1672°С. The dust-gas mixture leaving the MCP after the hot-water boiler enters the aspiration system. The dust extracted as a result of gas cleaning has an increased content of 30.02% potassium. The composition of the dust is given in Table 10. This is a consequence of its sublimation of the element first in the CP and the furnace of the TPP boiler, and then in the MCP. The reduction melting time in the MCP is 1688 s.

Scrap melting in the ladle-furnace unit

In the example under consideration, 10 tons of scrap metal are introduced into the technological process. Before loading into the gearbox, the scrap is melted in a ladle-furnace unit with arc heating. Since the amount of scrap involved is small, it is convenient to melt it directly in a ladle of 10 m ³ . For this, a ladle-furnace unit with arc heating (AKP) is used.

Scrap prepared for melting is loaded into a ladle. The ladle is fed under the accumulator of the TPP boiler and the slag accumulated during the previous metallurgical cycle is poured. In addition, cast iron obtained in the MCP is poured into the ladle. Thus, the melting of scrap is carried out under the slag, which allows minimizing the consumption of energy and electrodes. During the smelting process, coal is introduced into the melt in order to lower the melting point of the metal and lime in order to increase the basicity of the slag obtained from the thermal power plant. For post-combustion of exhaust gases from the bath, oxygen-containing blast is fed into the ladle. The cast iron and slag obtained during the smelting process are sent to the reduction stage of smelting in the KP. The temperature of cast iron and slag before loading into the gearbox is 1450°C.

Power generation

Each period of metallurgical melting in the KP corresponds to its own furnace mode of the boiler (TRK). Table 4 shows the duration of the TEC and shows the technological parameters that characterize the energy of the SER entering the furnace of the TPP from the CP, and Table 5 shows the material balances for the corresponding TEC.

Table 4 - Time of the fuel dispenser and parameters of the VER at the exit from the CP

1-0 1-1 1-2 1-3 1-4 1-5 2-1 2-2 2-3 3-1 Cycle Mode time, s 2830 1943 4304 3071 2189 1483 550 1100 720 4738 22927 ε _CO %* 83.7 65.88 67.29 67.40 67.39 67.39 1.52 27.01 100 100 73.50 Gas rate from gearbox, С 1650 1650 1650 1650 1650 1650 1630 1680 1670 0

* ε _CO is the degree of afterburning of CO in the gas phase at the outlet of the PC, %.

The time of the metallurgical cycle is 22927 s (6.37 h).

Table 5 - Material balances at the respective TEC TPPs

1-0
kg/s 1-1
kg/s 1-2
kg/s 1-3
kg/s 1-4
kg/s 1-5
kg/s 2-1
kg/s 2-2
kg/s 2-3
kg/s 3-1
kg/s per cycle
t/c PC dust 0.12 0.24 0.25 0.25 0.25 0.25 0.45 0.10 0.02 0 3.94 Gas from PC 4.00 8.00 8.00 8.00 8.00 8.00 4.40 5.02 1.06 0 123.95 Coal (Extra top) 2.14 1.39 1.43 1.43 1.43 1.43 0.94 1.28 2.75 2.84 41.91 Lime 0.49 0.30 0.33 0.33 0.33 0.33 0.21 0.24 0.64 0.65 9.53 The air is hot 20.93 17.12 17.19 17.19 17.19 17.19 18.19 18.62 23.84 24.67 446.91 Air cooler 4.07 3.89 3.73 3.72 3.72 3.72 8.74 7.19 3.98 4.42 96.73 Total: 31.75 30.94 30.93 30.92 30.92 30.92 32.93 32.45 32.29 32.58 722.97 Slag from KU 0.84 0.64 0.67 0.67 0.67 0.67 0.74 0.49 0.99 1.01 17.47 gas phase 30.78 30.20 30.14 30.14 30.14 30.14 32.10 31.89 31.13 31.41 702.68 Dust 0.14 0.11 0.11 0.11 0.11 0.11 0.10 0.08 0.16 0.16 2.84 Total: 31.76 30.95 30.92 30.92 30.92 30.92 32.94 32.46 32.28 32.58 722.99 Discrepancy, % 0.03 0.03 0.03 0.00 0.00 0.00 0.03 0.03 0.03 0.00 0.00

Table 6 shows the main technological parameters of the TPP operation during the entire metallurgical cycle.

Table 6 - Technological parameters of FC operation

1-0 1-1 1-2 1-3 1-4 1-5 2-1 2-2 2-3 3-1 b (g/kWh)* 322 210 215 216 216 216 141 194 314 329 Steam production, t/h 82.01 82.00 82.02 82.01 82.01 82.01 82.02 82.00 82.00 82.00 Steam temperature, C 535 535 535 535 535 535 535 535 535 535 Steam pressure, MPa 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8

* b – Specific fuel consumption, g/kWh.

Thus, the technological parameters of the boiler operation make it possible to ensure the constant regular operation of the turbine unit with a capacity of 21.3 MW with steam. At the same time, during the metallurgical cycle, the TPP generates 135,700 kWh of electricity, using an average of 276 g of reference fuel per kWh.

cement production

During the entire metallurgical cycle, 77.70 tons of slag are obtained from CP and MCP. The slag melts enter the mixer for averaging the chemical composition. The composition of the average slag is given in table 9. Depending on the production need, the slag from the mixer is distributed for further processing. In this example, 7.77 tons of slag is sent for granulation in order to obtain an active mineral additive [7. GOST 3476-74 Granular blast-furnace and electrothermophosphoric slags for cement production. - M .: "Standartinform", 1974. - 6 p.], and 69.93 tons are divided into 4 portions of 17.48 tons each and fed by a ladle to the saturation chamber.

Saturation chamber

Saturation chamber (KN) [3. RU2692532 C1, 2018, 4. EN 2710088 C1, 2017] is lined with magnesite lining and has a cylindrical-conical shape. The inner diameter of the central cylindrical part of the chamber is 3.3 m. The length of the central cylindrical part of the chamber along the lining is 8.0 m. The diameter of the necks through which the inserts are introduced is 1.25 m. The outer diameter of the inserts is 1.15 m. can be in the chamber - 23.0 m ³ . The camera rotates around a horizontal axis on support rollers. The camera rotation frequency is adjusted in the range (0–30) rpm. The rotation is set by four symmetrically located drives, which are synchronized during operation by hydraulic couplings. Torque from the drive is transmitted through two gears, symmetrically located relative to the center of the chamber. In the central part of the chamber there is a hatch for loading the melt and unloading the clinker into the refrigerator. The clinker cooler is placed directly under the saturation chamber. The clinker is cooled in the refrigerator by air flow in a fluidized bed on a grate. The outlet channel of the KH and the outlet channel of the clinker cooler are connected into one channel, which is suitable for the lime kiln unit. The lime kiln consists of two shafts working alternately. One shaft is under loading (unloading), and the other is in operation.

Saturation of molten slag with lime

The temperature of the lining KH before loading the material - 1300°C. First, 2.11 tons of lime and 0.6 tons of iron ore are introduced into the rotating KN through a feed insert. As a result of the rotation of the chamber, the material is heated. Next, a portion of slag from the mixer (17.48 t) is poured through the loading hatch. All this time, while the material is being loaded, the previous batch of clinker is cooled in the clinker cooler. Clinker cooling time in the refrigerator - 992 s. To start the process of alite formation, the raw mixture in KN is heated. To do this, 0.8 1 t of coal is fed into the chamber, and 1140 nm ^{3 of} oxygen are introduced through the side slots. As a result of fuel combustion and the formation of clinker minerals, the temperature of the raw mixture is raised to 1431°C. The synthesis of alite and belite continues for 1500 s. After this time, the heating of the chamber stops. To start the synthesis of low-melting minerals, the mixture is cooled. For this purpose, 4.76 tons of limestone are introduced into the chamber. As a result of the endothermic decarbonization reaction, the temperature of the mixture is reduced to 1291°C. The clinker is released into the refrigerator when about 3% of the liquid phase remains in the chamber. To unload, open the loading hatch, turn the chamber with the hatch down and, swinging the chamber, release the material into the refrigerator. The time taken to saturate one portion of the slag is 5194 s. As a result of saturation of the entire slag (four portions), 92.28 tons of clinker are obtained KN=0.91, n=2.01, p=2.34. The time for saturation of all portions of the slag is 20776 s (5.77 h).

Lime firing

In parallel with the production of clinker, lime is calcined. Roasting is carried out in two shafts located behind the saturation chamber. Shaft type units are widely used for lime burning. In our case, the mines work alternately. Roasting is carried out in one mine, and lime is unloaded and the next portion of limestone is loaded in the other. Obtaining four portions of clinker per cycle allows four lime firing cycles. For firing, 25.20 tons of limestone is loaded into the mine. Roasting begins with the supply of hot air from the clinker cooler to the working shaft. Air temperature 320°С. Feed time 992 s. Then, the gas phase leaving the KN is passed through the shaft. The average gas temperature is 1250°C. The time of its submission is 5194 s. With a specific heat consumption for roasting lime of 4.6 MJ/kg, 66.38 GJ is required for firing one portion, while 97.01 GJ leaves the refrigerator and saturation chamber. Thus, during one metallurgical cycle, it is possible to obtain 57.76 tons of lime, which is necessary for the reproduction of the method. The dust generated during the lime burning process is returned to production, as it contains a significant amount of CaO.

Gypsum production

The gas mixtures formed during the implementation of the method contain SO ₂ . Flue gases are cleaned from sulfur dioxide in a scrubber, washing the gas mixture with lime suspensions. As a result, 1.42 tons of gypsum is obtained, which is added to the cement mixture together with clinker and an active mineral additive.

Cleaning Portland cement from metal inclusions

In this example, get Portland cement with mineral additives CEM II/A-Sh [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.]. For this, a cement mixture is formed, which includes 92.28 tons of Portland cement clinker, 7.77 tons of active mineral additives and 2.04 tons of gypsum.

The cleaning of the cement mixture from metal inclusions is carried out in two stages. First, the cement mixture is subjected to selective grinding (only the non-metallic component of the mixture is crushed), and then, in the process of air separation, the more dense and not crushed metal is separated from Portland cement.

Results obtained during the implementation of the method

Thus, in the process of implementing the method, during one metallurgical cycle (6.37 h), 67.13 tons of steel 08 are obtained [8. GOST 1050-2013 Steel products from non-alloyed structural high-quality and special steels. General specifications. - M .: "Standartinform", 2014.- 32 p.], 102.10 tons of Portland cement with mineral additives CEM II / A-Sh [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.] and 135,700 kWh of electricity [9. GOST32144-2013 Power quality standards in general purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.]. At the same time, 37.5% of the generated electricity is consumed within the framework of the ETC, and 62.5% is sent to third-party consumers. Table 7 shows the articles of consumption of electricity received during one metallurgical cycle.

Table 7 - Items of electricity consumption

Total produced e. energy per cycle, kWh 135700 Energy consumption for the operation of TPP, kWh 8139 Energy consumption for oxygen production, kWh 20870 Energy consumption for casting and rolling, kWh 10730 Energy consumption for cement production, kWh 6738 Energy consumption for melting scrap in EAF, kWh 4382 Undistributed electricity, kWh 84841 Share of undistributed electricity, % 62.5

Product Ingredients

Table 8 - Dynamics of changes in the composition of the metal in the CP during the melting process

Si Mn Al S P C Cast iron from IPC 0.06 0.05 0.00 0.010 0.030 4.490 Chipboard cast iron 0.24 0.41 0.00 0.030 0.030 4.490 Cast iron after reduction melting 0.03 0.04 0.00 0.010 0.050 4.490 Cast iron after oxidative refining 0.00 0.00 0.00 0.010 0.003 3.094 Steel after oxidation of excess carbon 0.00 0.00 0.00 0.008 0.005 0.218 Steel after deoxidation-alloying 0.27 0.5 0.001 0.006 0.008 0.085

Table 9 - Compositions of slags obtained during the metallurgical cycle

FeO _{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} Slag from thermal power plant 1.62 11.83 23.68 9.93 52.13 0.43 0.05 0.01 0.01 0.28 0.03 0.00 Slag with MCP 0.10 0.00 25.82 8.88 59.79 0.50 0.05 1.45 2.97 0.29 0.05 0.10 Slag with chipboard in KP 1.60 11.76 23.77 9.97 52.10 0.43 0.05 0.01 0.01 0.28 0.03 0 Slag with recovery area 0.10 0.00 27.12 8.41 62.52 0.97 0.06 0.05 0.11 0.30 0.29 0.07 Slag with oxide sq. 3.66 1.22 19.45 13.47 60.44 0.48 0.09 0.04 0.08 0.57 0.32 0.18 slag recycled 0.00 2.16 7.36 16.38 52.06 21.21 0.01 0.00 0.01 0.69 0.14 0.00 Slag from the mixer 0.68 0.20 25.82 9.25 62.08 0.87 0.07 0.10 0.21 0.34 0.29 0.09

Table 10 - Compositions of fly ash and dust obtained during the production process

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} ZnO PbO SO _{3 P2O5 _} FROM Ash TPP 9.11 16.04 6.73 35.31 0.3 0.03 3.17 6.47 0.19 2.53 0.06 0.00 0.22 19.84 Dust MCP 9.44 4.59 1.62 9.98 0.09 0.01 14.69 30.02 0.06 20.94 0.50 0.42 0.78 6.86 Dust KN 1.07 5.07 1.08 91.02 0.06 0.00 0.02 0.04 0.02 0.00 0.00 0.42 0.00 1.20

Table 11 - Composition of clinker obtained in the saturation process

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} SO _{3 P2O5 _} 3.12 20.98 7.31 66.59 0.68 0.05 0.08 0.16 0.27 0.69 0.07

Saturation coefficient - КН=0.91;

silicate module – n=2.01;

Alumina module – p=2.34.

Example 2 . Processing of scrap with high copper content

Consider a special case of the implementation of example 1, when large scrap (10 tons) with a high copper content was received for processing. At the stage of scrap melting in the ladle furnace with arc heating (see example 1), sulfur (pyrrhotite) is introduced. As a result of the interaction of iron sulfide with copper, copper sulfide is formed, which passes into slag 2[Cu]+(FeS)=[Fe]+(Cu ₂ S). The molten metal obtained in the ACP, together with the slag, is sent to the reduction stage of melting in the roll-melting chamber. The recovery stage includes five heats, which are carried out at a basicity of B=2.3. In total, in the process of liquid-phase reduction of cast iron and oxidative refining of steel in the melting roll-chamber, the slag melt is changed six times. This ensures a high degree of desulfurization of the produced steel. After such a high-quality purification of the metal from sulfur, the further implementation of the method is carried out as in example 1.

Example 3. Processing of melted slag from an electric steel-smelting shop (ESPC).

In the process of oxidative refining of steel in arc steel-smelting furnaces (EAF), a slag melt is formed, which contains a large amount of iron. Table 15 shows the chemical composition of the slag melt. Sending this slag to the dump leads to the loss of metal and an increase in the cost of maintaining the dump. In addition, in the process of operation of the sections for the preparation of scrap of the ERS, a large amount of metal fines (0-10) mm is formed. Sending this little thing to the steel furnace leads to the loss of metal associated with its waste. In order to preserve this metal as much as possible, its melting must be carried out in a reducing atmosphere. As an example, consider the processing of slag melts and metal fines obtained in the process of electric steelmaking.

Process chambers

The device and overall dimensions of the process chambers are shown in example 1.

Recovery stage of melting

52 refining slags are supplied for processing from workshop EAFs, which are divided into two portions of 26 tons each and introduced into the CP at the first and second reduction melts. The slag obtained from the accumulator TPP 17.31 is introduced into the CP at the third reduction melt. Cast iron obtained in the IPC, 1.21 is introduced in the first reduction heat. Small scrap of 10 fractions (0-10) mm is introduced into the gearbox through the feed insert through the ferroalloy channel during the entire recovery stage. Table 12 shows the material balance of the recovery melts and the time of supply of charge materials to the CP (see Fig. 1). The compositions of the melt products are shown in tables 15-17.

Table 12 - Material balance of recovery heats

Material balance items 1st
pl-ka 2nd
pl-ka 3rd
pl-ka 4th
pl-ka 5th
pl-ka 6th
pl-ka Total
balance Material submission time, s 1209 2070 369 3539 2504 1843 11534 Recycled slag, t 0.67 1.81 2.18 2.02 1.47 1.06 0.67 Slag from the EAF for processing, t 26.00 26.00 0.00 0.00 0.00 0.00 52.00 Slag from the TPP storage tank, t 0.00 0.00 17.31 0.00 0.00 0.00 17.31 Cast iron with MCP, t 1.21 0.00 0.00 0.00 0.00 0.00 1.21 Scrap fraction (0-10) mm, t 1.87 2.35 0.32 2.45 1.73 1.28 10.00 Ore (approx. 20%, ore 80%), t 1.71 6.33 0.61 23.35 16.51 12.15 60.66 Coal grade "T", t 4.60 7.46 1.31 11.77 8.33 6.13 39.60 Flux, t 2.38 3.96 2.46 7.96 5.78 4.25 26.79 Blowing into the afterburning zone, t 3.61 6.65 1.41 13.00 9.21 6.78 40.65 Total income items: 42.03 54.56 25.60 60.55 43.03 31.64 248.89 Cast iron, t 13.86 15.95 2.18 16.62 11.75 8.64 69.01 Slag, including: 18.07 21.81 20.19 14.70 10.58 7.76 Slag left in the CP, t 1.81 2.18 2.02 1.47 1.06 0.00 Slag product, t 16.26 19.63 18.17 13.23 9.52 7.76* 84.57 Gas, t 9.93 16.46 3.15 28.40 20.10 14.79 92.83 Dust, t 0.16 0.33 0.09 0.82 0.59 0.43 2.42 Impurities of gas 0.03 0.04 0.01 0.05 0.04 0.03 0.19 Total expense items: 42.05 54.59 25.62 60.59 43.05 31.65 24.90 Balance discrepancy, % 0.04 0.05 0.04 0.06 0.05 0.04 0.05

* - The slag passes to the oxidative melting stage.

The recovery stage of melting is carried out at a melt temperature of 1450°C. The temperature regime is regulated by means of afterburning in the gearbox, a part of the combustible gases exhausted from the bath. To do this, an oxygen-containing blast is fed into the afterburning zone. Table 13 shows the heat balance of reduction heats, and table 14 shows the parameters characterizing the HOR, which is discharged from the CP to the TPP furnace.

Table 13 - Heat balance of reduction heats in CP

Heat balance articles 1 sq. MJ/s 2 sq. MJ/s 3 sq. MJ/s 4 sq. MJ/s 5 sq. MJ/s 6 sq. MJ/s Sum
GJ/area The heat content of the original slag 33.61 20.42 76.70 0.83 0.86 0.84 117.81 Heat content of introduced cast iron 1.29 0.00 0.00 0.00 0.00 0.00 1.56 Heat from gas afterburning in PC 44.62 43.72 52.48 47.68 47.74 47.74 540.06 Total: 79.52 64.14 129.18 48.51 48.60 48.58 659.43 Heat content of cast iron 14.74 9.90 7.63 6.03 6.02 6.02 88.64 Heat content of slag 22.13 15.55 79.84 6.05 6.15 6.13 136.48 Heat content of gas 19.49 18.97 May 20 18.63 18.63 18.63 217.14 Heat content of dust 0.28 0.32 0.44 0.41 0.41 0.41 4.40 Heat content of gas impurities 0.04 0.03 0.06 0.03 0.03 0.03 0.37 Heat for charge recovery 21.82 18.17 20.18 15.80 15.79 15.79 195.99 Heat to evaporate moisture 0.78 0.95 0.77 1.34 1.34 1.34 13.76 Heat loss through PC walls 0.27 0.27 0.27 0.25 0.25 0.25 2.96 Total: 79.55 64.16 129.24 48.54 48.62 48.60 659.72 Balance discrepancy, % 0.04 0.03 0.05 0.06 0.04 0.04 0.04

Further implementation of the method is carried out as in example 1.

Results obtained during the implementation of the method

As a result of the implementation of the method, during one metallurgical cycle, 65.88 tons of steel 08 [8] and 119.58 tons of Portland cement with mineral additives are obtained [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.]. In parallel with the saturation of the melt, 50.51 tons of lime are fired, which is used in the next metallurgical cycle. In addition, as a result of the operation of the TPP for the metallurgical cycle, 130400 kWh of electricity are obtained [9. GOST32144-2013 Power quality standards in general-purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.]. At the same time, 33.5% of the electricity is spent on the reproduction of the method (without casting and rolling), and 66.5% compensates for the need for electricity in the electric shop. The time of the metallurgical cycle is 6.12 hours. The time spent on processing slag into clinker is 5.69 hours.

Composition of products

Table 15 - The composition of the slag obtained for processing from the EAF furnace

FeO _{SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 44.83 11.78 5.26 24.93 7.59 5.48 0.00 0.00 0.00 0.02 0.11

Table 16 - The composition of the slag mixture in the mixer

FeO _{SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 0.74 23.79 9.27 57.38 4.89 3.22 0.07 0.15 0.22 0.21 0.06

Table 17 - Composition of clinker obtained in the process of saturation of the slag

Fe ₂ O _{3 SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 2.85 19.57 7.38 63.04 3.76 2.47 0.06 0.12 0.18 0.52 0.05

Saturation coefficient - КН=0.91;

silicate module – n=1.91;

Alumina module – p=2.59.

Example 4 Recycling of a technogenic dump (dump) of steelmaking

Today, the dumps of metallurgical plants contain billions of tons of steelmaking waste. The composition of non-metallic waste from steelmaking, operating according to the Scrap-DSP-AKP-CCM-Prokat scheme, includes: slag with EAF - 61.4%, slag with ACP - 20.5%, SGO dust - 0.3%, scale -7.3%, fireclay scrap - 7.9% and magnesite scrap - 2.5%. For simplicity of presentation, the listed waste sent to the dump will be called "Dump slag". Table 18 shows the composition of the waste slag, calculated on the basis of the above structure of the waste from the plant. This composition will be used in modeling the technological process.

Table 18 - The composition of the waste slag used in the calculation, wt.%

_{FeOsum SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 31.95 15.71 11.03 28.78 8.14 2.98 0.06 0.07 0.16 0.97 0.15

In addition to ceramics, the dump contains 15% of the metal carried away from metallurgical furnaces (splashes, beadlets, etc.).

The material from the dump enters the site for the preparation of dump slag. When preparing dump slag for production, it is cleaned from metal inclusions (addition), dried and averaged chemical composition. In the process of preparation, the non-metallic component of the slag-metal mixture is gradually converted into dust and removed by a controlled air flow. After each grinding stage, the material is dedusted and subjected to magnetic separation. For grinding the material, traditional crushing and grinding equipment is used, which provides the highest yield of fine fractions. Drum separators are used to remove dust from the slag-metal mixture at the initial stages of processing. The drum separator is a pipe with blades inside. The blades are oriented in such a way that during the axial rotation of the drum to ensure the movement of the material in the direction of unloading. In this case, smaller aggregates of slag under the action of a unidirectional air flow move rapidly in the drum, and the dusty fraction, moving at the speed of the air flow, is carried away into the aspiration system. At each stage of processing, magnetic separation of the dedusted product is carried out in order to extract the metal from the mixture. At the same time, large pieces of metal after the first stage of processing are returned to the metallurgical plant in the EAF (meaning the plant that owns the dump), and small metal is introduced into the CP at the reduction stage of melting. At the final stage, the material is crushed in a roller press and magnetic separation is not carried out, since after the roller press, almost all of the ceramic component of the mixture turns into a pulverized fraction and is removed into the aspiration system. In the process of air separation, the slag purified from metal is dried. To do this, the air supplied to the separators is heated using electrical energy.

When preparing waste slag, its chemical composition is averaged. In order to further increase the homogeneity of the product, at the final stage of processing, the material is accumulated and averaged in silos.

Melting roll chamber

The inner diameter of the chamber is 3.3 m. The length of the cylindrical part of the chamber along the lining is 8.0 m. The diameter of the discharge channel is 1.06 m. The mass of the chamber without melt is 194 tons. The allowable volume of melt that can be in the chamber is 23.0 m ³ . The gearbox rotates around the axis of symmetry on four support rollers. The rotational speed is regulated in the range (0–30) rpm. The rotation is set by four symmetrically located drives, which are synchronized during operation by hydraulic couplings. Torque is transmitted through two gears, symmetrically located relative to the center of the chamber. In the KP, liquid-phase reduction of cast iron, oxidative refining of steel and adjustment of the slag melt to obtain a ferroalloy are carried out.

Recovery stage of melting

In order to shorten the production cycle as much as possible and increase the productivity of the process, one melt is carried out at the recovery stage. After the previous metallurgical cycle, 8.93 tons of recycled slag remains in the CP. Before the start of the reduction stage of melting, 2.47 tons of slag from the storage tank of the TPP boiler is poured into the CP through the loading hatch. The initial slag obtained in this way in the CP is used as a reaction medium for liquid-phase reduction. During the smelting process, charge materials are introduced into the slag bath. The most important component of the charge mixture in this example is waste slag coming from the preparation area. In the process of reduction melting, 48.09 tons of prepared waste slag are introduced into the CP. In addition, 0.66 t of TPP fly ash and 22.87 t of coal are introduced into the composition of the charge mixture. In the example under consideration, brown coal from the Berezovsky deposit is used as a reducing agent and fuel for thermal power plants. The charge mixture flow rate is controlled in such a way that the foam on the melt surface does not turn into spray, and the gas velocity in the discharge channel does not exceed 40 m/s. Feeding time of charge materials - 6212 s. During the entire reduction melting, 5.00 tons of small scrap, extracted from the waste slag at the preparation site, is fed into the CP through a ferroalloy channel. Scrap consumption is regulated in such a way as not to overcool the roll chamber. Thermal balancing of the process is carried out by afterburning part of the combustible gases leaving the bath. To do this, oxygen is introduced through the side slots in the amount of 11555 nm ³ . In the process of reducing melting, 17.03 tons of pig iron and 44.00 tons of slag are obtained, and 42.13 tons of gas, 1.19 tons of dust and 0.17 tons of gas impurities go into the aspiration system. The degree of afterburning of CO in the gas mixture is 64.70%. Melting is carried out at a temperature of 1450°C, and the temperature of the dust-gas phase is 1650°C. The dust-gas mixture leaving the CP is directed through the discharge channel to the furnace of the TPP boiler. Recovery melting time - 6319 s.

Oxidative refining of steel

и неровностями футеровки доставляется через слой шлака в металл, а оставшаяся часть 597.82 нм³ участвует в окислении отходящего из ванны СО. Чтобы повысить основность шлака до В=2.78, в расплав вводят 9.43 т извести. В результате окислительного рафинирования получают 15.99 т стали с содержанием углерода С=1.0% и 53.83 т шлака. Температура расплава - 1520°С. Температура пылегазовой смеси на выходе из камеры - 1640°С. Степень дожигания СО в отходящей газовой смеси – 99.9%. Пылегазовая смесь по отводящему каналу поступает в топку котла ТЭС. Время окислительного рафинирования металла – 1200 с. После окислительного рафинирования нераскисленную сталь выпускают из КП. Состав стали приведен в таблице 19.The pig iron obtained in the reduction smelting process is subjected to oxidative refining in order to remove excess impurities (mainly phosphorus). To do this, 1331.01 nm ³ oxygen is supplied to the afterburning zone of the CP. Part of the oxygen-containing blast 733.19 nm ³ as a result of chamber rotation

and irregularities of the lining is delivered through the slag layer to the metal, and the remaining part of 597.82 nm ³ is involved in the oxidation of CO leaving the bath. To increase the basicity of the slag to B=2.78, 9.43 tons of lime are introduced into the melt. As a result of oxidative refining, 15.99 tons of steel with a carbon content of C=1.0% and 53.83 tons of slag are obtained. Melt temperature - 1520°C. The temperature of the dust-gas mixture at the chamber outlet is 1640°C. The degree of CO afterburning in the exhaust gas mixture is 99.9%. The dust-gas mixture enters the furnace of the TPP boiler through the discharge channel. The time of metal oxidative refining is 1200 s. After oxidative refining, non-deoxidized steel is released from the KP. The composition of the steel is given in table 19.

Table 19 - Composition of steel after oxidative refining

Fe Si Mn S P C 98.99 0 0 0.005 0.005 1.00

In the example under consideration, the non-deoxidized steel intermediate is transported by ladle to the metallurgical production (the plant on whose balance sheet the dump is located) to obtain graded steel.

Corrective recovery melt

The composition of the slag melt remaining in the CP is shown in Table 20.

Table 20 - The composition of the slag melt in the field of oxidative refining of steel

_{FeOsum SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 0.67 19.40 12.60 53.93 9.13 2.77 0.11 0.11 0.17 0.94 0.18

These data show that the melt after granulation can be used as AMD for cement in accordance with GOST3476-74 [7. GOST 3476-74 Granular blast-furnace and electrothermophosphoric slags for cement production. - M .: "Standartinform", 1974. - 6 p.]. The only indicator that reduces the quality of the slag is MnO. For grade I AMD, the MnO content should be <2%. To remove excess components from the melt, another corrective reduction melt is carried out. 1.94 tons of coal are introduced into the CP. Melting is carried out at a temperature of 1450°C. Thermal balancing is carried out by afterburning part of the combustible gases leaving the bath. To do this, 832 nm ³ oxygen is introduced into the CP through the side slots. In the example under consideration, as a result of reduction melting, 51.93 tons of corrected slag melt and 1.45 tons of ferromanganese FMn70 are obtained [10. GOST 4755-91 Ferromanganese. Technical requirements and terms of delivery. - M.: "Standartinform", 2011. - 16 p.]. The composition of the corrected slag melt is shown in table 21, and the composition of the ferroalloy - in table 22.

Table 21 - Composition of the corrected slag melt, wt. %

∑FeO _{SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} S _{P2O5 _} 0.01 20.03 13.04 56.02 9.44 0.23 0.03 0.06 0.18 0.84 0.12

Table 22 - Ferroalloy composition, wt.%

Fe Si Mn S P C 19.08 2.37 72.93 0.02 0.60 5.00

In the process of reduction smelting, 3.40 tons of gas leaves the CP, the degree of afterburning of which in terms of CO is 53.48%. Gas temperature - 1650°C. Together with gas, 0.05 t of dust and 0.13 t of gas admixture leave the CP. The dust-gas mixture is sent through the discharge channel to the furnace of the TPP boiler. Recovery melting time - 569 s.

After corrective melting, ferromanganese and most of the corrected molten slag are released from the KP. 8.93 tons of recycled slag is left in the chamber, which goes to the next metallurgical cycle. In the example under consideration, ferromanganese is sent to a metallurgical plant, and the corrected molten slag is sent to cement production in KN.

Power generation

The dust-gas mixture formed during the operation of the CP contains VER in the form of sensible heat and combustible gases. These energy resources are diverted to the furnace of the TPP boiler, where they are involved in the production of steam for the turbine of the electric generator. The consumption of WER from the CP during the entire metallurgical cycle varies. In order to ensure the specified steam output of the boiler under these conditions, each period of metallurgical melting in the KP corresponds to its own fuel dispenser. In the example under consideration, the following fuel dispensers are used: 1-1 - normal mode of reduction melting in the CP in order to obtain primary metal (cast iron); 2-1 - oxidative refining of the metal in the CP; 1-2 - regular mode of corrective reduction melting in the CP; 3-1 - autonomous mode of the boiler; 1-1-0 - transition from mode 3-1 to mode 1-1 (or from mode 1-1 to 3-1); 1-2-0 - transition from mode 3-1 to mode 1-2 (or vice versa).

Table 23 shows the duration of the TRC and shows the technological parameters that characterize the energy of the SER entering the boiler furnace of the TPP from the CP.

Table 24 shows the material balances at the respective TEC TPPs.

Table 25 shows the main technological parameters of the TPP operation during the entire metallurgical cycle.

Table 25 - Technological parameters of TPP operation

1-1-0 1-1 2-1 1-2-0 1-2 3-1 b (g/kWh)* 246.55 176.10 303.50 232.65 148.30 317.00 Steam production, t/h 82.01 82.01 82.01 82.01 82.01 82.01 Steam temperature, °С 535 535 535 535 535 535 Steam pressure, MPa 8.8 8.8 8.8 8.8 8.8 8.8

*b – Specific fuel consumption, g/kWh.

The technological parameters of the boiler operation make it possible to ensure the constant regular operation of the turbine unit with a capacity of 21.3 MW with steam. At the same time, for the metallurgical cycle, the TPP generates 56,730 kWh, using an average of 214.77 g of reference fuel per kWh. Table 26 shows the main items of electricity consumption in the example under consideration during one metallurgical cycle.

Table 26 - Items of electricity consumption ETC

Total produced e. energy per cycle, kWh 56730 Energy consumption for the operation of TPP, kWh 3404 Energy consumption for preparing slag for processing, kWh 2829 Energy consumption for oxygen production, kWh 7300 Energy consumption for cement production, kWh 4279 Energy released in the UES, kWh 38918 Share of energy supplied to the UES, % 68.6

cement production

After corrective recovery, 43.00 tons of slag is released from the CP. In the example under consideration, 4.30 tons of slag is sent for granulation in order to obtain AMD, and 38.70 tons is divided into 2 portions of 19.35 tons each and sent for saturation. Saturation of the melt is carried out in KN. The device and overall dimensions of the KN are shown in example 1. The temperature of the chamber lining before loading the material is 1300°C. First, 5.85 tons of lime, 0.95 tons of iron ore and 1.85 tons of flint (SiO ₂ ) are introduced into the rotating KN through a feed insert. As a result of the rotation of the chamber, the material is heated and mixed. Next, a portion of the melted slag (19.35 tons) is poured through the loading hatch. All this time, while the material is being loaded, the previous portion of the clinker is cooled in the clinker cooler. Clinker cooling time in the refrigerator is 995 s. To start the process of alite formation, the raw mixture in KN is heated. To do this, 1.32 tons of coal are fed into the chamber, and 1161 nm ^{3 of} oxygen are introduced through the side slots. As a result of fuel combustion and the formation of clinker minerals, the temperature of the raw mixture rises to 1472°C. The synthesis of alite and belite continues for 1500 s. After this time, the heating of the chamber stops. To start the synthesis of low-melting minerals, the mixture is cooled. For this purpose, 7.46 tons of limestone are introduced into the chamber. As a result of the endothermic decarbonization reaction, the temperature of the mixture is reduced to 1272°C. The clinker is released into the refrigerator when about 3% of the liquid phase remains in the chamber. To unload, open the loading hatch, turn the chamber with the hatch down and, swinging the chamber, release the material into the refrigerator. The time taken to saturate one portion of the slag is 3826 s.

As a result of saturation of two portions of slag, 64.84 tons of clinker are obtained KH=0.91, n=1.72, p=2.88. The chemical composition of the clinker is shown in table 27.

Table 27 - Composition of clinker obtained in the saturation process

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} SO _{3 P2O5 _} 2.84 18.88 8.17 62.56 5.66 0.14 0.04 0.04 0.11 1.49 0.07

The time for saturation of all portions of the slag, taking into account the cooling of the clinker in the cooler, is 8731 s (2.43 h).

Lime firing

In parallel with the production of clinker, lime is calcined. Roasting is carried out in two shafts located behind the saturation chamber. Obtaining two portions of clinker per cycle allows firing two portions of lime. For firing one portion, 103.3 tons of limestone are loaded into the mine. Roasting begins with the supply of hot air from the clinker cooler to the working shaft. Air temperature - 320°С. Feed time - 995 s. Then, the gas leaving the KN is passed through the mine. The average gas temperature is 1290°C. Gas supply time - 2770 s. With a specific heat consumption for burning lime of 4.6 MJ/kg, it takes 272 GJ to burn one portion, which is how much heat passes through the mine. Thus, during the metallurgical cycle it is possible to obtain 59.19 tons of lime. At the same time, 12.81 tons are spent on the implementation of the method, and 37.38 tons of excess lime is sold to third-party consumers. The dust generated during the lime burning process is returned to production, as it contains a significant amount of CaO.

Gypsum production

The gas phase formed during the implementation of the method contains SO ₂ . Flue gases are cleaned from sulfur dioxide using the lime method. As a result, 0.97 t of gypsum is obtained, which is introduced into the cement mixture along with clinker and AMD.

Results obtained during the implementation of the method

As a result of the implementation of the method, during one metallurgical (production) cycle, 15.99 tons of steel intermediate with a content of C=1.0%, 1.45 tons of ferromanganese FMn70 are obtained [10. GOST 4755-91 Ferromanganese. Technical requirements and terms of delivery. - M.: "Standartinform", 2011. - 16 p.] and 70.54 tons of Portland cement with mineral additives [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.]. In addition, as a result of the operation of the TPP for the metallurgical cycle, 56,730 kWh of electricity are obtained [9. GOST32144-2013 Power quality standards in general-purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.]. At the same time, 31.4% of electricity is spent on the reproduction of the method (without pouring and rolling), and 68.6% is sold to third-party consumers. The time of the metallurgical cycle is 9588 s. The time spent on the processing of slag into cement - 8731 s.

Example 5

Let us consider a particular case of the implementation of example 4, when a complex oxidizer is used to burn fuel at a thermal power plant, which includes technical oxygen and a gaseous body filler (NGT). The composition of the gas body filler is shown in Table 28.

Table 28 - Filler composition of the gas body vol.%

_{CO2 SO2 H2O O2} N ₂ 95.00 0.00 4.00 0.00 1.00

Power generation

Table 29 shows the duration of the TRC and shows the technological parameters that characterize the energy of the dusty gas phase (the main fuel) entering the furnace of the TPP from the CP.

Table 30 shows the material balances at the respective TEC TPPs.

Oxygen (T=26°C) and gas body filler (T=350°C) are supplied to the furnace through separate channels, and their mixing is carried out directly in the boiler furnace. As a result of the operation of TPPs, 136,600 kWh of electricity are received in one production cycle [7. GOST 3476-74 Granular blast-furnace and electrothermophosphorus slags for cement production. - M .: "Standartinform", 1974. - 6 p.], while consuming 291.34 grams of standard fuel per kWh. The composition of the gas mixture leaving the TPP boiler after dedusting and desulfurization is shown in Table 31.

Table 31 - The composition of the gas mixture with TPP after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 70.27 0.00 28.36 0.00 1.37

Table 32 shows the main technological parameters of the TPP operation during the entire metallurgical cycle.

Table 32 - Technological parameters of TPP operation

1-1-0 1-1 2-1 1-2-0 1-2 3-1 b (g/kWh)* 240.90 170.80 298.60 226.15 141.30 311.00 Steam production, t/h 82.01 82.01 82.01 82.01 82.01 82.01 Steam temperature, С 535 535 535 535 535 535 Steam pressure, MPa 8.8 8.8 8.8 8.8 8.8 8.8

* b – Specific fuel consumption, g/kWh.

The technological parameters of the boiler operation make it possible to ensure the constant regular operation of the turbine unit with a capacity of 21.3 MW with steam. At the same time, for the metallurgical cycle, the TPP generates 56,680 kWh, using an average of 209.32 g of reference fuel per kWh.

Steel and cement production

In this example, steel and Portland cement are produced as in example 4.

During the production cycle receive 15.97 tons of steel intermediate with a content of C=1%, 70.60 tons of Portland cement [5. GOST 31108-2016 General construction cements. Specifications. - M.: "Standartinform", 2016. - 12 p.]. In addition, 38.34 tons of excess lime are obtained. Table 33 shows the average composition of the gas mixture leaving the saturation roll chamber and the lime kiln during the production cycle.

Table 33 - The composition of the gas mixture from the roll-chamber saturation, vol.%.

_{CO2 SO2 H2O O2} N ₂ 92.05 0.00 7.49 0.31 0.15

Preparation of gas body filler and production of CO ice ₂

The technological scheme for the preparation of the gas body filler and the production of dry ice is shown in Figure 2. During the production cycle (2.66 hours), 261.66 tons of gas from the thermal power plant and 63.11 tons of gas from the roll saturation chamber are supplied to the production of NGT and the production of dry ice (CO ₂ ). These gas mixtures contain 283.07 tons of CO ₂ . Table 34 shows the material balance of the gas body filler production.

Table 34 - Material balance of oil and gas production.

Parish, t/c Consumption, t / c Gas. mixture with KN 54.15 Gas body filler 168.00 Gas. mixture with TPP "without purification" 86.55 Condensate 0.11 Gas. mixture with TPP "after cleaning" 26.41 Total: 168.11 water vapor 1.00 Total: 168.11 Discrepancy, % 0.000

In the considered case of the implementation of the method, 7.13 tons of gas with KH are sent for cryogenic cleaning. This is done in order to send the maximum possible amount of gas from the TPP “without purification” to the oil and gas pipeline. Thus, 54.15 tons and 86.55 tons of gas from TPPs are sent to the NGT without treatment. In addition, 1.00 tons of steam is introduced into the filler of the gaseous body. (T=300°C). This allows, on the one hand, to reach the specified content of H ₂ O in the NHT (see Table 28), and on the other hand, to raise the temperature of the filler to 31°C before it is fed into the heater of the TPP boiler. The gas (149.92 t) remaining after the production of NGT is sent for cryogenic treatment and ice production (CO ₂ ). To cool the gas mixture during ice production, the products of cryogenic air rectification obtained during the production cycle at the oxygen station are used: 49.45 tons of liquid oxygen, 2.76 tons of liquid argon and 158.50 tons of liquid nitrogen. The production of liquid nitrogen within the framework of the ETC led to an increase in the specific consumption of electricity for the production of oxygen. If in carbon-positive production (examples 1-4) this figure is 0.455 kWh/m ³ O ₂ , then in carbon-neutral production (in this example) it was 0.794 kWh/m ³ O ₂ . At the first stage of pre-cooling, the gas mixture in heat exchanger 4 is cooled to a temperature of 273 K, using 3.84 tons of dry ice obtained in the previous production cycle as a coolant. As a result, it is converted into condensate and 2.37 t H ₂ O are removed. At the second stage of pre-cooling, in heat exchangers 5,6 and 7, the gas mixture to be purified is cooled to a temperature of 195 K, using nitrogen, oxygen and argon, which have passed into the gas phase in the process of making ice. At this pre-cooling stage, 0.38 t of excess components (H ₂ O and SO ₂ residues) are separated from the gas mixture as it passes into the solid phase. In the diagram, the condensate and excess components are shown together 2.75 tons. At the stage of phase transformation (obtaining ice), the gas mixture to be purified is divided into two portions. The first portion of 97.10 tons is sent for cooling with liquid nitrogen, and the second 50.02 tons for cooling with liquid oxygen and argon.

The first portion is compressed in the compressor 8 to 0.37 MPa, 133.80 tons of liquid nitrogen are introduced into it and sent to the expander 9. In this case, the thermodynamic system “gas to be purified - liquid nitrogen” is formed. As a result of heat exchange and mechanical work performed by this thermodynamic system (the expander rotates the electric generator), energy is removed from carbon dioxide with the formation of dry ice (CO ₂ ) and secondary nitrogen (gas). Dry ice CO ₂ is retained in the settling chamber of the expander 10, and secondary nitrogen with a temperature of T _WN =194 K is removed, taking nitrogen and oxygen with it from the gas mixture being purified. Part of the secondary nitrogen removed from the expander chamber 95.00 tons is sent to recuperative heat exchangers 11 and 12, where it is cooled with liquid oxygen and liquid argon. In this case, the phase transformation of liquid heat carriers (O ₂ and Ar) into gas occurs.

The second portion of the gas mixture to be purified (50.02 t) is compressed in compressor 13 to 0.31 MPa, 95.00 t of cooled secondary nitrogen and 24.73 t of liquid nitrogen are introduced into it and sent to expander 14. This forms the thermodynamic system “the gas mixture being purified - cooled secondary nitrogen ( gas) - liquid nitrogen. As a result of heat exchange and mechanical work performed by this thermodynamic system (the expander rotates the electric generator), energy is removed from carbon dioxide with the formation of dry ice (CO ₂ ) and secondary nitrogen (gas). Dry ice CO ₂ is retained in the settling chamber of the expander 10, and secondary nitrogen with a temperature of T _WN =194 K is removed, taking nitrogen and oxygen with it from the gas mixture being purified. In addition, as a result of the rotation of expanders 9 and 14, electric generators produce 4647 kWh of electricity, which is used in the ETC.

The secondary coolants (N ₂ , O ₂ and Ar) formed at the stage of phase transformation are used as coolants at the stage of pre-cooling of the gas mixture to be purified. After that, 160.25 tons of secondary nitrogen is sent to the production of nitrogen fertilizers, and oxygen and argon are used in the process. Oxygen as an oxidizing agent, and argon as an inert gas.

As a result of cryogenic cleaning, 145.41 tons of dry ice are obtained. At the same time, 119.0 tons of ice are sent by rail for further processing, and 26.41 tons are sublimated and sent to the mixing gas holder 3, where the CNG is formed. At the same time, 3.84 tons of ice are used as a coolant at the pre-cooling stage in heat exchanger 4, and 22.57 tons are defrosted in a sublimation plant, obtaining electricity. To do this, dry ice from the warehouse through the gateway 16 is introduced into the sublimation chamber 17, where it turns into a gas, cooling the water from the TPP condenser. By adjusting the flow of ice, an excess pressure of 3.0 MPa is created in the sublimation chamber. Further, carbon dioxide, through the heat exchanger 18, enters the turbine of the electric generator 19, where it performs work, producing 540 kWh of electricity. Electricity is used within the framework of the ETC, and 22.57 tons of CO ₂ enters the mixing gas tank 3, where the NGT is formed.

During the production cycle, the resulting gas mixture accumulates in the gas holder 3, which is fed into the mixing heater 20, where 1.00 tons of water vapor with a temperature of 300°C is introduced into it. As a result, NHT of a given composition is obtained (see table 28) with a temperature of 31°C. Part of the NGT 163.61 tons is fed into the heater of the TPP boiler, and the rest is sent to the technological subsystem.

Table 35 shows the balance of electricity in a carbon neutral ETC (Example 5) and a carbon positive ETC (Example 4).

Table 35 - Balance of electricity in the ETC during the cycle.

Name of balance sheet items Example 5 Example 4 Receipt articles Produced by energy at TPPs, kWh 56680 56730 Produced by energy on expanders, kWh 4647 0 Produced by energy during ice defrosting, kWh 540 Total: 61867 56730 Expenditure items For operation of TPP, kWh 3401 3404 Waste slag preparation costs, kWh 2836 2829 For the production of oxygen for technological. subsystems, kWh 13610 7300 For the production of oxygen for energy. subsystems, kWh 14010 0 For compressing gas mixtures before expanders, kWh 3752 0 For cement production, kWh 4283 4279 Electricity sent to the UES, kWh 19975 38918 Total: 61867 56730

The given data show that in example 5, new items of electricity consumption have appeared related to the production of oxygen for the energy subsystem of the ETC and the compression of the gas mixture before the expanders. In addition, due to the release of liquid nitrogen, oxygen production has become more energy intensive. At the same time, in example 5, new sources of energy appeared, associated with the operation of expanders and the defrosting of part of the ice. Thus, the resulting energy consumption in the production of dry ice was (14010+3752)-(4647+540)=12575 kWh. If this energy is related to the mass of CO ₂ formed in the ETC (283.07 tons), then we get the specific energy consumption associated with the separation and desublimation of carbon dioxide. In the example under consideration, this figure is 0.160 GJ/t CO ₂ , and if we take into account the costs incurred by metallurgical production, obtaining more energy-intensive oxygen, then it will increase to 0.233 GJ/t CO ₂ .

Results obtained during the implementation of the method

Thus, in a particular case of the implementation of the method, in 9579 s (2.66 h), 56.73 tons of dump steel-smelting slag are processed at the ETC, 15.97 tons of refined steel intermediate (C = 1%) are produced in ingots, 1.45 tons of ferromanganese (FM70 GOST4755-91), 70.60 tons of Portland cement with AMD (CEM II/А-Ш GOST31108-2016) and 61867 kWh of electricity. At the same time, 41,892 kWh of electricity is used within the framework of the ETC, and 19,975 kWh of carbon-neutral electricity (32.29%) is sent to third-party consumers in the UES. In addition, 119.0 tons of dry ice are sent to the consumer.

Example 6

To minimize the energy costs associated with the release and desublimation of carbon dioxide, we will select the power of the TPP, which is part of the ETC (example 5). To do this, we will calculate two ETCs. We will introduce a TPP with a capacity of 18 MW into one of them, and a TPP with a capacity of 25 MW into the other. Table 36 shows the results of the selection of TPP capacity.

Table 36 - Results of TPP capacity selection

Power of TPP as a part of ETC, MW 18.0 21.3 25.0 Share of the energy subsystem in the ETC, c.u. 0.450 0.507 0.545 Energy consumption for isolation and desublimation of CO ₂ , GJ/tCO ₂ 0.237 0.233 0.236

The share of energy or process subsystems in the ETC was calculated as the share of electricity consumption for oxygen production for these subsystems (see Table 35). The results obtained show that the lowest energy consumption during the release and desublimation of carbon dioxide 0.233 GJ/t CO ₂ is achieved at a TPP power of 21.3 MW, as was the case in example 5.

Claims (9)

1. A method for the production of steel, electricity and Portland cement in one energy-technological complex, including liquid-phase reduction of cast iron, oxidative refining and deoxidation-alloying of steel in a roll melting chamber, lime saturation of the resulting slag melts in a saturation roll chamber, cooling the resulting clinker in a clinker refrigerator, the formation of a Portland cement mixture, its selective grinding and separation of Portland cement from metal inclusions in the air separation process, characterized in that the liquid-phase reduction of cast iron is carried out in the process of the reduction stage of melting, including at least one liquid-phase reduction melting, and the number of such melts in stage is determined based on the volume of cast iron collected in the melting roll chamber before oxidative refining, and electricity is produced at a thermal power plant by burning fuel, obtaining a radiating gaseous body, transferring thermal energy and from the gas body to water, obtaining water vapor and converting steam energy into electrical energy, moreover, the dust-gas phase from the melting roll-chamber is burned out in the furnace of the boiler of the thermal power plant in accordance with the furnace mode of the boiler, providing the specified mode of operation of the turbine of the electric generator during the metallurgical cycle of the operation of the roll - melting chambers, while the furnace mode of the boiler determines the consumption of the main fuel - the dust-gas phase from the melting roll-chamber, additional fuel and oxidizer, in addition, the slag melt and fly ash from the thermal power plant are used in reduction melts, and the dust-gas mixture leaving from saturating roll-chamber and clinker cooler are used as a heat carrier during lime roasting, which is used to saturate slag melts and as a flux in steel production, while all gas mixtures formed during the implementation of the method after their use are dedusted and subjected to desulfurization, and the resulting and in the process of desulfurization, gypsum is used as a technological additive in the formation of Portland cement mixture. 2. The method according to claim 1, characterized in that at the reduction stage of melting, scrap metal is introduced into the melting roll chamber, while scrap metal of a fraction of 0-50 mm is introduced in the solid state, and larger scrap is first melted under a layer of melted slag coming from thermal power plant, and then poured into the melting roll chamber along with slag, and in the process of melting scrap metal containing copper, sulfur is introduced into the metal. 3. The method according to claim 1 or 2, characterized in that melts of ferrous slags and iron-carbon alloys are used as the reaction medium for the liquid-phase reduction of cast iron. 4. The method according to any one of claims 1-3, characterized in that the raw materials supplied for processing from the dump are prepared and introduced into the melting roll chamber at the reduction stage of melting, while in the process of preparation the material is crushed, separated from metal inclusions , dry and average its chemical composition, and the non-metallic component of the material is introduced into the technological process as part of the charge mixture, and the metal - together with scrap metal. 5. The method according to any one of claims 1-4, characterized in that in order to optimize the temperature of the radiating gas body, a coolant gas is introduced into it, in addition, corrective additives are introduced into the slag melt formed in the furnace of the boiler of a thermal power plant, allowing to optimize it chemical composition and viscosity, while the flow rate of the gas-cooler and corrective additives is determined by the combustion mode of the boiler, ensuring the specified mode of operation of the turbine of the electric generator during the metallurgical cycle. 6. The method according to any one of claims 1 to 5, characterized in that the molten slag remaining in the melting roll chamber after the steel is tapped is subjected to corrective reduction melting to obtain a corrected molten slag used in the method in the production of cement. 7. The method according to any one of claims 1-6, characterized in that when burning fuel at a thermal power plant, a complex oxidizer is used, including oxygen and a gas body filler, while oxygen is introduced in proportion to the organic component of the fuel, ensuring the required completeness of its combustion, and the consumption , the composition and temperature of the filler are regulated in such a way as to form a radiating gaseous body during combustion, capable of providing the required mode of water evaporation and steam production with specified parameters. 8. The method according to any one of claims 1 to 7, characterized in that the gas mixtures formed during the implementation of the method after dedusting and desulfurization are used in the formation of a gas body filler, for this, excess nitrogen is removed from them and the missing water is introduced in the form of steam. 9. The method according to any one of claims 1 to 8, characterized in that part of the gas mixtures formed at the thermal power plant after dedusting and desulfurization is subjected to cryogenic cleaning to obtain dry ice, and one part of the resulting ice is subjected to sublimation and used in the preparation of a gas body filler, and the other is accumulated in storage facilities, while the products of cryogenic air rectification and the sublimated part of ice are used to cool the gas mixtures to be purified, and the power of the thermal power plant is selected in such a way as to minimize the energy costs associated with the production of dry ice.

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