RU2775066C1 - Method for producing electricity, ferrosilicon and aluminiferous cement - Google Patents

Abstract

FIELD: engineering.

SUBSTANCE: invention relates to the production of electricity, ferrosilicon and aluminiferous cement within a single power engineering complex. Method includes burning the organic fuel component in the boiler of a thermal power plant so as to produce electricity. Processing the mineral fuel component in the form of slag melt and ash in roll chambers. Conducting liquid phase reduction of the slag melt and ash in a melting roll chamber, resulting in ferrosilicon and slag melt, further supplied into a saturation roll chamber containing burnt lime, wherein said melt is saturated with lime, resulting in an aluminiferous clinker melt. Performing finishing processing of the ferrosilicon and aluminiferous clinker outside of the roll chambers by pouring and cooling. Forming a cement mix from the aluminiferous clinker and process additives and purifying said mix from metal inclusions. The dust and gas phase from the melting roll chamber is after-burned in the boiler of the thermal power plant. The furnace mode of the boiler therein determines the consumption of primary and auxiliary fuel.

EFFECT: reduction in the energy costs and emission of carbon dioxide into the atmosphere.

6 cl, 2 dwg, 36 tbl, 4 ex

Description

The invention relates to energy, metallurgy and cement production. The method can be used to produce: electricity, ferrosilicon and aluminous cement in accordance with current technical requirements. When implementing the method, primary sources of raw materials and energy are used: coal, iron ore and limestone. In addition, they use secondary material and energy resources (VMR and VER) obtained in the process of energy, metallurgical and cement production. These include: electricity, hot furnace gases, molten slag, dust from the air cleaning system, substandard alloys, waste slag, scrap metal, coal energy waste, etc.

A known method of generating electricity at a thermal power plant [1. Kudinov A.A. Thermal power plants. Schemes and equipment: a tutorial. - M.: Infra-M. 2015. - 325], [2. Zhikhar G.I. Boiler installations of thermal power plants: a tutorial. - Minsk. "The Highest School". 2015. - 525] and [3. Kizilstein L.Ya. Traces of coal energy (article) // Science and Life - 2008. - No. 5. - S. 42-47], including combustion of the organic component: coal, steam production, conversion of steam energy into electrical energy and processing of the mineral component of coal by cooling the slag melt, mixing it with ash and burying the ash and slag mixture, followed by the development of the burial site as a technogenic deposit . The disadvantage of this method is the loss in the process of cooling the slag melts of a significant part of the VER, which makes it unprofitable to process the ash and slag mixture into energy-intensive products, such as ferrosilicon and aluminous cement. This method is not analogous to the claimed method, since it does not apply to metallurgy and cement production.

A known method of joint production of ferrosilicon and aluminous cement [4. Butt Yu.M., Okorokov S.D., Sychev M.M., Timashev V.V. Technology of binders: a textbook for universities / ed. Yu.M. Butta - M .: "Higher School", 1968. - 620 p.]. The method includes melting scrap with simultaneous reduction of silicon in an electric arc furnace. The method does not produce electricity, so it cannot be analogous to the proposed method.

Known device "roll-camera for the implementation of thermochemical processes” [5. 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 device cannot be analogous to the method.

A known method of joint production of steel and Portland cement [6. RU 2710088 C1, 2017]. The method uses technological chambers: a melting chamber (KP) and a saturation chamber (KN). The camera is an analogue of a roll-camera [5. RU 2692532 C1, 2018]. According to the method, liquid-phase reduction of cast iron, oxidative refining and deoxidation-alloying of steel are carried out in KP, and Portland cement clinker is obtained in KN by saturating slag melts obtained in KP with lime. The cement mixture is cleaned from metal inclusions in the process of selective grinding and air separation. In addition, the dust-gas phase is withdrawn from the CP and burnt out in the waste heat boiler. This method cannot be analogous to the claimed method, since it belongs to another field of technology.

Thus, the present invention has no analogues.

The objective of the invention is to propose a method for the production of electricity, ferrosilicon and aluminous cement within a single energy technology complex (ETC). In this complex, the energy subsystem should produce electricity, and the technological subsystem - ferrosilicon and aluminous cement. In this case, the energy subsystem will process the SER and SMR generated 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 opens 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 for the production of electricity from ferrosilicon and aluminous cement. In the proposed method, electricity, ferrosilicon and aluminous cement are produced within one ETC. Electricity is obtained at a thermal power plant by burning the organic component of the fuel, obtaining a radiating gaseous body, transferring thermal energy from the gaseous body to water, obtaining water vapor and converting the steam energy into electrical energy. And ferrosilicon and aluminous clinker melt are obtained in roll-chambers by processing the mineral component of the fuel. First, the liquid-phase reduction of ferrosilicon is carried out in the melting roll-chamber, and then the slag melt is saturated with lime from the melting roll-chamber in the saturation roll-chamber, thereby obtaining aluminous clinker melt. The finishing treatment of ferrosilicon and aluminous clinker is carried out outside the roll chambers by pouring and cooling them. In this case, the cooling mode of the clinker melt is chosen in such a way as to obtain a given mineralogical composition of the alumina clinker. The cement mixture is formed from clinker and technological additives. Cleaning of the cement mixture from metal inclusions is carried out in the process of selective grinding and air separation. In addition, the dust-gas phase from the melting roll-chamber is burnt out in the furnace of the boiler of the thermal power plant, while the combustion of the organic component of the fuel is carried out in accordance with the combustion mode of the boiler (TRK), ensuring the constant regular operation of the turbine of the electric generator. The combustion mode of the boiler determines the consumption of the main fuel, auxiliary fuel - the dust-gas phase from the melting roll-chamber and the oxidizer. The dust-gas mixture from the saturation roll-chamber is used as a heat carrier for lime calcination behind the saturation roll-chamber, while all gas mixtures formed during the implementation of the method are dedusted and subjected to desulfurization after their use.

In particular cases of the implementation of the method, a coolant gas and corrective additives are additionally supplied to the boiler of a thermal power plant to adjust the content of CaO, FeO, SiO ₂ and Al ₂ O ₃ in the slag melt, and their consumption is determined by the combustion mode of the boiler.

In particular cases of the implementation of the method in the liquid-phase reduction of ferrosilicon, the following are used: dust, slag melts, scrap metal and man-made waste from ash and slag dumps.

In particular cases of the implementation of the method, when burning the organic component of the fuel, a complex oxidizer is used, including oxygen and a gaseous body filler. Oxygen is introduced into the oxidizer 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 gas mixtures formed during the implementation of the method, after dedusting and desulfurization, are used as a filler of the gas body. To this end, excess nitrogen is removed from them and the missing water 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 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.

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 has declined. This is because coal, unlike natural gas, does not burn completely. In the production of energy, only the organic component of coal is used, and its mineral component, during the combustion process, is converted into ash and slag. Slag is formed in the boiler furnace of a thermal power plant (TPP), and 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. In this regard, after the completion of this process, 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 slag is involved in production in the form of a melt with a temperature of (1400-1600) ° C. For this, furnaces with liquid slag removal are used. The melt is accumulated in the storage tank of the TPP boiler and is periodically released for processing. The chemical composition of traditional cements and VMP, formed during coal combustion at thermal power plants, consists of more than 90% SiO ₂ , CaO, Al ₂ O ₃ and Fe ₂ O ₃ . In this regard, in order to obtain cement of a given composition, it is necessary to restore excess oxides from the slag melt and add the missing ones. Since it is difficult to restore CaO and Al ₂ O ₃ , either Fe ₂ O ₃ or Fe ₂ O ₃ and SiO ₂ are restored. Thus, the content of hard-to-recover oxides (CaO and Al ₂ O ₃ ) in SMR is a determining factor in the choice of processing technology. In the proposed method, the mineral component and waste from a coal thermal power plant are processed, where Al ₂ O ₃ >CaO.

To remove excess components from the melt, the method uses liquid-phase reduction, that is, metal reduction is carried out from the liquid phase (slag melt). Obviously, the slag melt must contain at least oxides of the metal being reduced. In this regard, to activate and control the reduction process, charge materials are introduced into the melt. The charge mixture includes a reducing agent, metal-containing materials and (if necessary) a flux. The melting of solid charge materials occurs in the process of liquid-phase reduction.

<1. При этом восстановление SiO₂ идет до тех пор, пока B≤1. В связи с этим в рассматриваемом способе проводят кислый восстановительный процесс. Для этого КП футеруют кислыми или нейтральными огнеупорами, а расход шихтовых материалов регулируют таким образом, чтобы основность реакционной среды (расплава) была меньше единицы. В предлагаемом способе при жидкофазном восстановлении ферросилиция в камеру плавления вносят шлаковый расплав и золу-унос, образующиеся при производстве электроэнергии на ТЭС. Шлаковый расплав используют как реакционную среду (жидкую фазу) и металлосодержащий материал, а золу-унос ТЭС как восстановитель и металлосодержащий материал. Таким образом, в предлагаемом способе в товарный продукт перерабатывают все золошлаковые отходы, образующиеся при производстве электроэнергии на угольной ТЭС.To obtain ferrosilicon from molten slag, it is necessary to recover not only all the iron, but also part of the silicon. At the beginning of the reduction melting, iron is reduced from the molten slag, and then, in its presence, silicon is also reduced. To restore silicon in a roll melting chamber (CM), conditions are created under which the activity of SiO ₂ will be higher than the activity of CaO. It is known from the theory of metallurgical processes that silicon has a higher activity in melts where the basicity, that is, the ratio B=

<1. When this recovery of SiO ₂ goes as long as B≤1. In this regard, in the considered method, an acidic reduction process is carried out. To do this, the CP is lined with acidic or neutral refractories, and the consumption of charge materials is regulated so that the basicity of the reaction medium (melt) is less than one. In the proposed method, during the liquid-phase reduction of ferrosilicon, melted slag and fly ash, which are formed during the production of electricity at thermal power plants, are introduced into the melting chamber. Slag melt is used as a reaction medium (liquid phase) and metal-containing material, and fly ash from TPP as a reducing agent and metal-containing material. Thus, in the proposed method, all ash and slag waste generated during the production of electricity at a coal-fired thermal power plant is processed into a commercial product.

In particular cases of the implementation of the method, in the liquid-phase reduction of ferrosilicon, I use: dust, metallurgical slag melts, substandard alloys, scrap metal, waste slag, etc. The use of these metal-containing and carbon-containing materials in the process of liquid-phase reduction increases the efficiency of metallurgical production and simultaneously solves the problem of waste processing.

Roll-melting chamber (KP) [6. RU 2710088 C1, 2017], in which liquid-phase reduction of ferrosilicon is carried out, is a semi-batch chemical reactor, where one part of the product is accumulated, and the other part, the gas phase, is continuously discharged into the boiler furnace of a thermal power plant at a thermal power plant. Since the gas is removed in real time, the parameters of the gas flow are an important information channel for managing processes in the CP and in the furnace of the TPP boiler. So the temperature and chemical composition of the gas make it possible to evaluate the energy of the process, and the change in its consumption - to evaluate the intensity of the reduction processes (MeO + C = Me + CO) in the chamber and clarify the consumption of materials introduced into the furnace of the TPP boiler. On FIG. 1 shows a graph of the change in gas flow in the outlet channel of the chamber during reduction melting, from the beginning of the introduction of charge materials to the release of products. The graph is a trapezoid ABCD. τ2 - time of supply of charge materials. 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 τ1 is the time it takes to reach the normal melting mode. ВС=τ3 - operating time in normal melting mode. It is defined as the difference τ2 - τ1. The height of the trapezoid q _g - second gas flow through the outlet channel in the normal mode of melting. This flow rate is constant, since in the normal mode, the exhausted coal particles are replaced by newly introduced into the chamber. The angle of inclination of the side CD characterizes the decay rate of the reduction processes in the chamber after the supply of charge materials is stopped, and τ4 is the decay time of the process. If during the melting process the fractional and grade composition of the reducing agent does not change, then τ1=τ4, and the trapezoid ABCD is isosceles. The base of the trapezoid AD=τ5=τ2+τ1 is the total melting time, from the beginning of the material supply to the release of products. The area of the trapezoid is equal to the gas flow rate through the discharge channel for melting V _g , the Gas flow rate is determined from the material balance of the melting.

In the method under consideration, the dust-gas phase formed in the CP during reduction melting (liquid-phase reduction of ferrosilicon) is used as an auxiliary fuel in the production of steam for the turbine of an electric generator. The consumption of the dust-gas phase from the CP during the entire metallurgical cycle varies. In order, under these conditions, to ensure the specified steam output of the boiler, the main fuel is introduced into the furnace. Usually, coal is used as the main fuel in the method, the ash of which has a high content of Al ₂ O ₃ . However, in particular cases of the implementation of the method, peat, oil shale, fuel oil, natural gas, etc. are used as the main fuel.

Each period of metallurgical melting in the KP corresponds to its own furnace mode of the boiler (TRK). The fuel dispenser is the consumption of the main fuel, auxiliary fuel (dust-gas phase from the CP) and oxidizer determined by calculation.

Afterburning in the boiler furnace of hot gases from the melting chamber leads to an excessive increase in the temperature of the resulting gaseous body. In this regard, in particular cases of implementing the method for optimizing the technological parameters of the radiating gaseous body, the fuel dispenser determines the flow rate, chemical composition and temperature of the coolant gas. Usually, air or a filler of a gaseous body (triatomic gases) is used as a coolant gas. The introduction of a gas-cooler makes it possible to keep the temperature of the radiating gaseous body at a comfortable level for the radiation chamber of the boiler.

In the method under consideration, boilers with liquid slag removal are used. In this case, the slag is not removed immediately, but accumulated to a certain volume. After tapping, the melted slag is first involved in the production of ferrosilicon, and then in the production of cement. In this regard, in particular cases of the implementation of the method, corrective additives are introduced into the boiler furnace, and the fuel dispenser determines their consumption, temperature and chemical composition. Additives 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 melt in the boiler storage tank, and, on the other hand, to obtain the required chemical composition of the melt for subsequent processing. The introduction of corrective additives into the boiler furnace reduces the efficiency of a thermal power plant, but increases the energy efficiency of metallurgical and cement production in the energy technology complex.

To ensure the specified steam capacity of the boiler in a specific period of metallurgical melting in a roll melting chamber. Shared by three main fuel dispensers. TRK-1 at the recovery stage of melting in the KP. In particular cases of the implementation of the method, it may include the main fuel, auxiliary fuel (dust-gas phase from the CP), oxidizer, coolant and corrective additives. TRK-2 at the oxidative stage of melting, if oxidative refining of the reduced metal is carried out. TRK-3 - during autonomous operation of the boiler, when the boiler is separated from the gearbox by a shutter. At this moment, the dust-gas phase from the saturation roll-chamber does not enter the boiler, and it operates only on the main fuel. In addition, the following are added to the furnace: an oxidizing agent, a coolant and corrective additives. For a more accurate calculation of the technological parameters of TPPs, TRK-1, TRK-2 and TRK-3 are specified, divided into several modes. So TRC-1 is divided according to the number of heats at the recovery stage. Usually, only one reduction melt, TRK1-1, is used in the process. At the same time, it should be noted that the dust-gas phase, which comes from the CP, is involved in TRK1-1 during the period when the melting takes place in the normal mode (see Fig. 1). If the reduction melting in the CP is still (already) not in the normal mode, then TRK1-0 is used - including the corresponding VER from the CP. With a more accurate calculation, TRK-3 is divided into three modes TRK3-1, when the steam consumer is only the turbine of the electric generator, 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 and TRK3-3, when steam is spent on the turbine and on the production of thermal energy. Thus, using the TRC, the technological parameters of the thermal power plant are determined during the entire metallurgical cycle of the CP operation from the start of the supply of charge materials to the production of ferrosilicon and slag melt.

The ferrosilicon obtained in the process of liquid-phase reduction is released from the CP (saturation roll-chamber) and sent for finishing, which includes: pouring, cooling, crushing, sorting, etc. In particular cases of the implementation of the method, when the ferroalloy is released from the roll chamber, as well as during its pouring and cooling, it is protected from oxidation by an inert gas.

Aluminous cement is a hydraulic binder intended for the manufacture of quick-hardening, building and heat-resistant mortars and concretes. The content of basic oxides in aluminous cement varies within the following limits: Al ₂ O ₃ - (35-80)%; CaO - (18-32)%; SiO ₂ - (0.5-2)%; Fe ₂ O ₃ - (0.5-1)% [9]. The main minerals of aluminous cement are calcium aluminates, which determine the processes of hydration and increase in the strength of the cement stone. The most important mineral is the single calcium aluminate CaO ^. Al ₂ O ₃ .

и FeO

. Чтобы привести шлаковый расплав к заданному составу глиноземистого цемента в него необходимо внести CaO, Fe₂O₃ и т.д. При этом основным вносимым компонентом (по вносимой массе) является СаО. Насыщение расплава известью производят в рол-камере насыщения (КН) [6] в два этапа. Сначала в КН обжигают известь, которую предполагается внести в шлаковый расплав, а затем в известь заливают шлаковый расплав из камеры плавления. В результате интенсивного перемешивания в КН получают клинкерный расплав, который выпускают из камеры насыщения, разливают в изложницы и направляют на охлаждение.The slag melt obtained as a result of liquid-phase reduction has an increased content of Al ₂ O ₃ , basicity B=

and FeO

. To bring the slag melt to a given composition of aluminous cement, it is necessary to add CaO, Fe ₂ O ₃ , etc. to it. In this case, the main introduced component (according to the introduced mass) is CaO. Saturation of the melt with lime is carried out in a saturation roll chamber (KN) [6] in two stages. First, lime is fired in the KN, which is supposed to be introduced into the slag melt, and then the slag melt is poured into the lime from the melting chamber. As a result of intensive mixing in KN, a clinker melt is obtained, which is discharged from the saturation chamber, poured into molds and sent for cooling.

An important role in the production of aluminous cements is played by the mode of cooling of the clinker melt, which is determined based on the chemical composition of the melt and the specified strength characteristics of the cement. Usually, the cooling of clinker in molds is carried out in a special area. Refrigerators, heaters and heating wells for annealing hardened clinker are installed at this site. Each clinker composition has its own cooling mode.

The clinker obtained during the cooling of the melt may contain metal inclusions. The presence of metal in cement is undesirable, since the building material obtained using this cement and the metal may have different coefficients of volumetric expansion. This can lead to the destruction of building structures. Cleaning the cement mixture from the metal is carried out in two stages. First, selective grinding of the cement mixture is carried out, and then, in the process of air separation, the denser metal is separated from the well-ground and less dense cement.

The dust-gas phase leaving the roll-chamber is used as a heat carrier for lime calcination. To do this, a firing unit is installed behind the saturation chamber with the possibility of supplying a dust-gas mixture into it. First, the dust-gas phase, which is formed during the burning of lime in the chamber itself, is fed into the unit, and then the dust-gas mixture, which is formed during the saturation of the melt with lime. If in the process of such firing, the energy of the exhaust gases from the KN was not enough for the final firing of a given volume of lime, then this substandard lime is finally burned in KN at the next production cycle of the method.

When implementing the method, a large amount of gas mixtures are formed, which are separated from dust and subjected to desulfurization. For dust removal of gas mixtures, cyclones, filters, electrostatic precipitators and other units and aspiration complexes are used. The extracted dust, depending on its composition, is returned to production or sold as a commercial product.

Fly ash from thermal power plants contains iron and carbon. Therefore, it is used as a charge material in the liquid-phase reduction of ferrosilicon. In addition, ash may have an increased content of: Na, K, Zn, Pb, etc. This is a consequence of the double sublimation of these components, first in the melting roll-chamber, and then in the furnace of the TPP boiler. By re-assigning the material to production, we contribute to an even greater accumulation of sublimated components in the mixture. In this regard, before the next supply of TPP ash to production, the composition of the sublimated components is determined. When the content of the individual components reaches the specified values, the material is removed from production and sent to the consumer. Dust is sent as a raw material to non-ferrous metallurgy enterprises or as fertilizer to agriculture.

The dust extracted from the gas mixtures involved in the burning of lime contains a lot of CaO and is used as a raw material in the desulfurization of gas mixtures, when the melt is saturated with lime, or is shipped to consumers.

To remove sulfur (SO ₂ ) from gas mixtures, various desulfurizers and scrubbers are used, the operation of which is based on intensive washing of gases with lime suspensions. In particular cases of the implementation of the method, the gypsum obtained as a result of such washing is used as an additive in the preparation of cement mixtures.

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 gaseous body filler. Thus, in the combustion mode of the boiler (TRK), along with oxygen, one more 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, allows you 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, and 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, a radiating gaseous body is formed in the boiler furnace, which includes primary gas - the result of oxidation of organic fuel components by oxygen and a gaseous body filler. 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 filler of the gas body, and to increase the steam output, the filler is partially replaced by the 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 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 . On FIG. Figure 2 shows a schematic flow diagram for the preparation of NGT and cryogenic cleaning of flue gases within 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, Oxygen Station 1 produces not only liquid oxygen and liquid argon, but also liquid nitrogen.

Flue gases from TPP 2 and cement production 3 (clean gas) are supplied for processing. Gas from metallurgical production is used in thermal power plants. The gas phase from TPP 2 is sent to gas tank 4, and from cement production 3 - to gas tank 5. At the same time, part of the gas from TPP (gas without purification) and the main part of pure gas is sent to mixing gas tank 6, where the composition of the CNG is formed. The rest of the gas from the TPP from the gas holder 4 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 7, water condensate is removed from the gas mixture. The temperature of the gas mixture in the heat exchanger 7 - T _cm ≥273 K. In the second stage of pre-cooling in heat exchangers 8, 9 and 10, 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 of T _cm =(273-195) K. Thus prepared, 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 distillation, namely liquid nitrogen, liquid oxygen and liquid argon, are used as coolants. 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 the compressor 11, liquid nitrogen is introduced into it and sent to the expander 12. In this case, a heterogeneous thermodynamic system "the 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=194K). 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 log

(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 11, 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 12 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 13, where dry ice CO ₂ is retained, and secondary nitrogen with a temperature of T _wN =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 13 is cooled in recuperative heat exchangers 14 and 15. 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 11 and sent to the expander 12. , dry ice (CO ₂ ) and new secondary nitrogen (gas) are formed. Dry ice is retained in the settling chamber of the expander 13, and secondary nitrogen with a temperature of T _WN =194 K is removed from the chamber, taking with it nitrogen and oxygen 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 16. One portion of the ice to be sublimated is first sent to heat exchanger 7, where it changes its state of aggregation, cooling the gas mixture supplied for cleaning, and then to mixing gas holder 6, where CNG is formed . Another portion of ice is fed through lock 17 to sublimation chamber 18, where it changes its state of aggregation, cooling water from the TPP condenser. By adjusting the supply of ice, excess pressure is created in the sublimation chamber. High-pressure gas from the chamber 18 is heated in the heat exchanger 19 and performs work by rotating the turbine of the electric generator 20. 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 6, where the gas turbine is formed.

The flow rate of gas mixtures used in the formation of CPG is regulated in such a way that the nitrogen content in the resulting composition does not exceed the allowable value. The resulting gas mixture is fed from the gas holder 6 to the boiler TPP 2 through the mixing heater 21, 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, which 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 earth, and an increase - 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: steelmaking, energy and cement industries within 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 energy, ferroalloy 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

As an example, consider the operation of the energy technology complex (ETC), which produces electricity [7. GOST 32144-2013 Power quality standards in general purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.], ferrosilicon FS75 [8. GOST 1415-93 Ferrosilicon. Technical requirements and terms of delivery. - Minsk: Interstate Council for Standardization, Metrology and Certification, 1993 - 14c], aluminous cement HZ [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

Power generation

МДж/кг. Технический состав угля и состав золы, усреднено по Подмосковному угольному бассейну, приведен в таблицах 1 и 2.Electricity is produced at TPPs with a capacity of 50 MW. Brown coal of the B2 brand, mined in the Tula, Smolensk, Ryazan, Kaluga and Tver regions, is used as fuel.

MJ/kg. The technical composition of coal and the composition of ash, averaged over the Moscow region coal basin, are given in tables 1 and 2.

Table 1 - The composition of coal for the working mass,% (wt.)

C ^p H ^p N ^p O ^p S ^p A ^r V ^p W ^p 28.7 2.2 0.6 8.6 2.7 25.2 21.4 32.0

Table 2 - Composition of coal ash, % (wt.)

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO 8.0 48.0 37.5 5.5 1.0

The melting roll chamber (MC) is connected by a discharge channel to the furnace of the TPP. This will make it possible to use the incandescent dust-gas phase (VER), which is formed in the process of reducing melting in the KP, as a fuel in the production of electricity. Each period of metallurgical melting in the KP corresponds to its own furnace mode of the boiler (TRK). Air is used as the oxidizer and refrigerant gas. Table 3 shows the duration of the TRC and shows the technological parameters that characterize the energy of the dusty gas phase (auxiliary fuel) entering the furnace of the TPP from the CP.

Table 3 - Time of the fuel dispenser and parameters of the VER at the exit from the CP

1-0 1-1 3-1 per cycle Mode time, s 584 1577 1439 3600 ε _CO %* 99 99 0 Gas rate from gearbox, С 1675 1675 0

* ε _CO - The degree of afterburning of CO in the gas phase at the outlet of the CP, %.

Production cycle time 3600 s (1.00 h). Table 4 shows the material balances of fuel combustion at the respective fuel dispensers.

Table 4 - Material balances of fuel combustion at TPPs

Table 5 shows the main technological parameters of the TPP operation during the entire metallurgical cycle.

Table 5 - Technological parameters of TPP operation

1-0 1-1 3-1 per cycle b (g/kWh)* 364.15 341.90 386.40 363.30 Steam production, t/h 198.1 198.1 198.1 198.1 Steam temperature, С 535 535 535 535 Steam pressure, MPa 8.8 8.8 8.8 8.8

* b - Specific fuel consumption, g/kWh.

As a result of the operation of TPPs, in one production cycle (3600s) they receive 50,000 kWh of electricity, while consuming 363.30 grams of reference fuel per kWh. The main items of consumption of electricity produced within the framework of the ETC are shown in Table 6.

Table 6 - Items of electricity consumption in ETC

Total produced e. energy per cycle, kWh 50000 Energy consumption for TPP operation, kWh 3000 Energy consumption for oxygen for roll cameras, kWh 3897 Energy consumption for cement production, kWh 1256 Energy released in the UES, kWh 41847 Share of energy supplied to the UES, % 83.7

Reduction melting in a melting roll chamber

The inner diameter of the melting roll chamber (CP) is 3.3 m. The length of the cylindrical part of the chamber along the lining is 2.42 m. The outlet channel diameter is 1.06 m. The mass of the melting chamber without melt is 54.0 tons. m ³ . KP is lined with acid refractories and rotates around the axis of symmetry on four support rollers. The rotation frequency is varied 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. Charge materials are introduced into the CP through the supply insert, and the dust-gas mixture is removed through the discharge insert. The discharge channel of the KP is connected through a system of gates with the TPP boiler. On the central cylindrical part of the KP there is a loading hatch, a sliding gate for discharging liquid products of melting and a mechanism for sampling.

To obtain ferrosilicon from molten slag, TPPs recover all the iron and part of the silicon. The driving force of the recovery process is the carbon introduced into the CP with coal and ash from TPPs. At the same time, the carbon accumulated in the alloy also takes an active part in the reduction process and can be completely depleted if active components remain in the melt.

To obtain ferrosilicon of a given composition, iron ore or silicon is additionally introduced into the CP.

For thermal balancing of the process, CO coming from the bath is burned in the CP, and in case of a lack of heat, natural gas and oxygen are supplied to the afterburning zone.

Before the start of reduction melting, 11.66 tons of slag is poured into the CP through the loading hatch, released from the storage tank of the TPP boiler. 5.78 tons of T grade coal, 1.51 tons of TPP fly ash, and 0.11 tons of iron ore are fed into the rotating chamber through the feed insert. The technical composition of coal grade "T" and the chemical composition of its ash are given in tables 7 and 8.

Table 7 - The composition of coal grade "T" for the working mass,% (wt.)

C ^p H ^p N ^p O ^p S ^p A ^r V ^p W ^p 68.6 3.1 1.5 3.1 0.4 16.8 9.97 6.5

Table 8 - The composition of the ash of coal grade "T",% (wt.)

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO _{Na2O K2O TiO2} 12.0 55.0 25.0 3.5 1.0 0.7 1.4 0.7

The charge material flow rate is controlled in such a way that the fictitious velocity of gases leaving the bath is in the range (0.3-1.7) m/s. The material feed time is 1869 s (see Fig. 1). For afterburning of combustible gases formed in the melting chamber, oxygen is introduced in a volume of 6013 nm ³ . In the process of melting, 3.66 tons of FS75 ferrosilicon [8] and 6.73 tons of alumina slag are obtained. The compositions of the products obtained during the implementation of the method are shown in tables 9-14. Melting is carried out at a temperature of 1520°C. In the process of reduction melting, 17.05 tons of gas goes into the furnace of the TPP boiler through the outlet channel. The degree of afterburning of CO in the gas mixture is 99.9%. Additional fuel is not introduced into the afterburning zone of the melting roll-chamber. Together with flue gases, 0.19 tons of dust and gas impurities leave the CP. The temperature of the dust-gas mixture is 1675°C. Dust discharged into the furnace of TPP has a high content of potassium. This is a consequence of the sublimation of this element, first in the furnace of the TPP boiler, and then in the CP. In this regard, the content of K ₂ O in the composition of TPP fly ash increases from cycle to cycle. When the content of K ₂ O in the ashes of TPPs>15% is reached, it is not put into processing, but is shipped to the consumer as a potash fertilizer. The total time of reduction melting, taking into account the release of products, is 3061 s.

Saturation of molten slag with lime in a saturation roll-chamber

The inner diameter of the saturation roll chamber (KN) is 3.3 m. The length of the cylindrical part of the chamber along the lining is 2.42 m. The diameter of the discharge channel is 1.06 m. The mass of KN without melt is 54.0 tons. The allowable volume of melt that can be in the chamber is 6.0 m ³ . KN has a main lining and 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. A loading hatch is located in the central part of the KN.

The slag melt obtained in the melting chamber corresponds in terms of alumina content to high-alumina cement VHC-II, but due to the increased content of SiO ₂ , MgO and TiO ₂ it cannot be shipped in this capacity to the consumer. In this regard, the melt is saturated with lime to obtain HZ cement [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

In the example under consideration, prior to saturation, lime is fired in the technological chamber, which is supposed to be introduced into the melt, and then the slag melt to be saturated is introduced into this lime. Roasting of lime does not lengthen the processing cycle, since it is carried out at the time when aluminous slag melt is obtained in the KP.

For burning lime, 8.51 tons of limestone are loaded into KN. To compensate for the energy costs for endothermic processes, 1.74 tons of T-grade coal, 2379 nm ^{3 of} oxygen and 293 nm ^{3 of} air are added to the KN. As a result, 5.07 tons of lime, 8.83 tons of gas phase and 0.13 tons of dust are obtained. The temperature of the dust-gas mixture is 1415°C. The lime burning time is 1097 s; it is controlled by the charge materials consumption. The gas flow velocity in the discharge channel is 30 m/s.

At the final stage, 6.73 tons of slag from the KP and 0.90 tons of iron ore (corrective additive) are added to the CC. To reach the desired melt temperature, 0.13 t of T coal, 171 nm ^{3 of} oxygen and 21.0 nm ^{3 of} air are introduced. As a result, 12.56 tons of clinker melt, 0.42 tons of gas phase and 0.12 tons of dust are obtained. The compositions of the products are shown in tables 9-14. The temperature of the dusty gas phase is 1654°C. Melt temperature 1465°C. Time of saturation of the melt with lime 1140 s.

The total time of processing of the slag melt into KN, including the roasting of lime, the saturation of the melt with lime and the release of alumina clinker melt is 2837 s.

Clinker melt cooling

The resulting clinker melt in its chemical composition corresponds to the type of HZ [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.]. However, in order to achieve the specified strength characteristics of cement, it is necessary to properly crystallize it. To do this, the melt obtained as a result of saturation is poured into molds and sent to a site for controlled cooling. Cooling is carried out with a water spray, followed by firing in heating wells.

Cement cleaning from metal inclusions

After cooling the clinker melt, a cement mixture is formed, which includes 12.56 tons of clinker and 0.26 tons of gypsum, which is obtained in the process of desulfurization of exhaust gas mixtures. To prevent metal inclusions from entering the cement, it is cleaned. Cleaning is carried out in two stages. First, the selective grinding of the non-metallic component of the cement mixture is carried out, and then, by controlled air flow, the well-ground and less dense aluminous cement is separated from the denser and not ground metal. The result is 12.82 tons of aluminous cement HZ [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

Lime firing per KN

The dust-gas mixture formed in the saturation roll-chamber upon receipt of the clinker melt is used for burning lime in a unit located behind the chamber. The calcining unit includes two calcining shafts operating alternately. One shaft is under loading and unloading, and the other is working. By the beginning of firing, 4.42 tons of limestone is in the working shaft. First, the gas phase is fed into the mine, which is formed in the KN during the roasting of lime. The temperature of the gas mixture is 1415°С, the time of this period is 1097 s. Then, a gas mixture is fed into the mine, which is formed when the melt is saturated with lime. The temperature of the gas mixture is 1654°C, the time is 1140 s. With a specific heat consumption for burning lime of 4.6 MJ/kg, 11.65 GJ of heat is required to burn the indicated portion, while 16.69 GJ of heat enters the mine from the KH. Thus, during the production cycle (3600 s) in the working mine, 2.53 tons of lime can be obtained for KH, which is used in the desulfurization of exhaust gases, obtaining gypsum.

Compositions of the resulting products

Table 9 - Compositions of secondary resources received for processing from thermal power plants

ΣFeO _{SiO2 Al2O3 _} CaO MgO _{Na2O K2O} ZnO S C TPP slag 8.00 47.90 37.38 5.48 1.00 0.00 0.00 0.00 0.24 0.00 Fly ash TPP 6.88 41.23 32.18 4.72 0.86 0.43 0.87 0.03 0.00 12.80

Table 10 - Composition of secondary resources from reduction smelting

ΣFeO _{SiO2 Al2O3 _} CaO MgO _{Na2O K2O TiO2} ZnO S C Slag 0.10 11.00 75.35 11.06 2.06 0.10 0.20 0.10 0.00 0.03 0.00 Dust 4.11 15.68 9.79 1.44 0.31 4.60 9.21 0.09 0.37 3.19 51.21

Table 11 - Composition of ferroalloy FS75 GOST1415-63

Fe Si Mn S P C 23.43 76.52 0.001 0.028 0.011 0.01

Table 12 - The composition of the aluminous clinker melt HZ according to GOST969-91

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} SO _{3 P2O5 _} 6.12 9.44 41.33 41.42 1.16 0.00 0.07 0.15 0.08 0.22 0.01

Table 13 - The composition of the gas mixture with TPP after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 17.69 0.00 19.54 0.68 62.09

Table 14 - The composition of the gas mixture from the roll-chamber saturation after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 78.92 0.00 16.29 0.01 4.78

Results obtained during the implementation of the method

Thus, as a result of the operation of the ETC during the production cycle (3600 s), 50,000 kWh of electricity are obtained [7. GOST 32144-2013 Power quality standards in general purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.]. At the same time, 41847 kWh (83.7%) are released into the country's energy system, and 8153 kWh (16.3%) of energy is spent within the framework of the ETC, receiving 3.66 tons of ferrosilicon FS75 [8. GOST 1415-93 Ferrosilicon. Technical requirements and terms of delivery. - Minsk: Interstate Council for Standardization, Metrology and Certification, 1993 - 14 p.] and 12.82 tons of aluminous cement HZ [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

Example 2

As an example, let's consider the work of the energy technology complex (ETC), which processes the ash and slag dump of a coal-fired thermal power plant. While producing electricity [7. GOST 32144-2013 Power quality standards in general purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.], ferrosilicon FS70 [8. GOST 1415-93 Ferrosilicon. Technical requirements and terms of delivery. - Minsk: Interstate Council for Standardization, Metrology and Certification, 1993 - 14 p.], aluminous cement HZ [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.]. Consider one production cycle of processing 9841 s (2.73 h). The production cycle time is defined as the time interval between the outlets of the melted slag from the storage tank of the TPP boiler. In this example, it is 9841 s (2.73 h).

Preparation of waste slag for processing

During one production cycle, 58.65 tons of dump slag are delivered by dump truck to the processing site. In the process of processing, garbage is removed from dump slag, crushed and dried. For grinding, 1699 kWh of electricity is used, and for drying 9685 m ^{3 of} natural gas. 51 tons of dry ash and slag mixture are sent to production. The composition of the ash and slag mixture prepared for processing is given in Table 15.

Table 15 - The composition of the ash and slag mixture from the TPP dump

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} C _H2O 12.67 47.06 22.62 1.90 0.92 0.00 0.93 1.81 0.78 10.86 0.45

Power generation

МДж/м³. Рол-камера плавления (КП) связана отводящим каналом с топкой ТЭС. Это позволят использовать в качестве дополнительного топлива при производстве электроэнергии раскаленную пылегазовую фазу, образующуюся в процессе восстановительной плавки в КП. Каждому периоду металлургической плавки в КП соответствует свой топочный режим котла (ТРК). В качестве окислителя и газа-охладителя, в примере, используют воздух. В таблице 16 показана продолжительность ТРК и приведены технологические параметры, характеризующие энергетику пылегазовой фазы, поступающей из КП. В этом примере пылегазовую фазу из КП считаем вспомогательным, а природный газ основным топливом для производства электроэнергии. В таблице 17 показаны материальные балансы сжигания топлива при соответствующих ТРК. Electricity is produced at TPPs with a capacity of 50 MW. Natural gas with lower calorific value is used as fuel

MJ / m ³ . The melting roll chamber (MC) is connected by a discharge channel to the furnace of the TPP. This will make it possible to use the incandescent dusty gas phase, which is formed in the process of reducing melting in the KP, as an additional fuel in the production of electricity. Each period of metallurgical melting in the KP corresponds to its own furnace mode of the boiler (TRK). Air is used as the oxidant and refrigerant gas in the example. Table 16 shows the duration of the TRC and shows the technological parameters that characterize the energy of the dusty gas phase coming from the CP. In this example, we consider the dust-gas phase from the CP to be auxiliary, and natural gas to be the main fuel for generating electricity. Table 17 shows the material balances of fuel combustion at the respective fuel dispensers.

Table 16 - Time of the fuel dispenser and parameters of the VER at the exit from the CP

1-0 1-1 3-1 per cycle Mode time, s 228 8712 901 9841 ε _CO %* 99 99 0 Gas rate from gearbox, С 1673 1673 0

ε _CO - The degree of afterburning of CO in the gas phase at the outlet of the CP,%.

Table 17 - Material balances of fuel combustion at TPPs

As a result of the operation of TPPs, in one production cycle (9841 s) they receive 58230 kWh of electricity, while consuming 292.85 grams of standard fuel per kWh. Table 18 shows the main technological parameters of the TPP operation during the metallurgical cycle.

Table 18 - Technological parameters of TPP operation

1-0 1-1 3-1 per cycle b (g/kWh)* 271.85 222.3 321.40 232.52 Steam production, t/h 198.1 198.1 198.1 198.1 Steam temperature, С 535 535 535 535 Steam pressure, MPa 8.8 8.8 8.8 8.8

* b - Specific fuel consumption, g/kWh.

The main items of consumption of electricity produced within the framework of the ETC are shown in Table 19.

Table 19 - Items of electricity consumption in ETC

Total produced e. energy per cycle, kWh 58230 Energy consumption for TPP operation, kWh 3494 Energy costs for slag preparation 1699 Energy consumption for oxygen for roll cameras, kWh 16990 Energy consumption for cement production, kWh 3101 Energy released in the UES, kWh 32946 Share of energy supplied to the UES, % 56.6

Reduction melting in a roll melting chamber

The inner diameter of the melting roll chamber (CM) is 3.3 m. The length of the cylindrical part of the chamber along the lining is 5.20 m. The outlet channel diameter is 1.06 m. The mass of the melting chamber without melt is 115.0 tons. m ³ . KP device as in example 1.

After the previous reduction melting, 4.00 tons of recycled slag are left in the CP. Before the start of reduction melting, 0.883 tons of slag, released from the storage tank of the TPP boiler, is poured into the CP through the loading hatch. 22.18 tons of “T” grade coal are fed through the feed insert into the rotating chamber by pneumatic transport. The technical composition of coal grade "T" and the chemical composition of its ash are shown in tables 7 and 8. Together with coal, 51.00 tons of prepared waste slag (ash) from the TPP are fed into the roll chamber. The material feed time is 8826 s (see Fig. 1). For post-combustion formed in the melting chamber of combustible gases injected oxygen in the amount of 30903 nm ³ . During the melting process, 16.92 tons of ferrosilicon FS70 are obtained [8. GOST 1415-93 Ferrosilicon. Technical requirements and terms of delivery. - Minsk: Interstate Council for Standardization, Metrology and Certification, 1993 - 14 p.] and 20.11 tons of alumina slag. The compositions of the products obtained during the implementation of the method are shown in tables 20-25. Melting is carried out at a temperature of 1530°C. In the process of reduction smelting, 82.88 tons of gas goes into the furnace of the TPP boiler through the outlet channel. The degree of afterburning of CO in the gas mixture is 99%. Together with flue gases, 2.30 tons of dust and gas impurities leave the CP. The temperature of the dust-gas mixture is 1673°C. Dust discharged into the furnace of TPP has a high content of potassium. This is a consequence of the sublimation of this element, first in the furnace of the TPP boiler, and then in the CP. In this regard, at the next production cycle, TPP fly ash is not sent for processing, but is shipped to the consumer as a potash fertilizer. The total time of reduction melting, taking into account the release of products, is 9840 s.

Saturation of molten slag with lime in a saturation roll-chamber

The inner diameter of the saturation roll chamber (KN) is 3.3 m. The length of the cylindrical part of the chamber along the lining is 5.20 m. The diameter of the outlet channel is 1.06 m. The mass of KN without melt is 115.0 t. ³ . KN device as in example 1.

For burning lime, 22.30 tons of limestone is loaded into the KN. To compensate for the energy costs for endothermic processes, 4.37 tons of T-grade coal, 5967.09 nm ^{3 of} oxygen and 733.97 nm ^{3 of} air are introduced into the SC. As a result, 13.24 tons of lime, 22.57 tons of gas phase and 0.33 tons of dust are obtained. The temperature of the dust-gas mixture is 1348°C. Lime firing time 6897 s. The time is controlled by the charge materials consumption. In this example, the firing time is slowed down so that the chamber is not idle (not cooled down). Therefore, the materials are fed in such a way that the gas flow velocity in the discharge channel does not exceed 12 m/s.

At the final stage, 16.11 tons of slag from the KP and 2.00 tons of iron ore (corrective additive) are introduced into the SC. To reach the specified melt temperature, 0.34 tons of T-grade coal, 467.56 nm ^{3 of} oxygen and 57.57 nm ^{3 of} air are introduced. As a result, 31.01 tons of clinker melt, 1.12 tons of gas phase and 0.31 tons of dust are obtained. The compositions of the products are shown in tables 20-25. The temperature of the dusty gas phase is 1640°C. Melt temperature 1482°C. Time of saturation of the melt with lime 1800 s.

The total time of processing of the slag melt into KN, including the roasting of lime, saturation of the melt with lime and the release of alumina clinker melt - 9297 s.

Clinker melt cooling

The cooling of the clinker melt is carried out as in example 1.

Cement cleaning from metal inclusions

After cooling the clinker melt, a cement mixture is formed, which includes 31.01 tons of clinker and 0.63 tons of gypsum. The cleaning of the cement mixture from metal inclusions is carried out as in example 1. As a result, 31.64 tons of aluminous cement HZ are obtained [9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

Lime firing per KN

The dust-gas mixture formed in the roll-chamber of saturation upon receipt of the clinker melt is used for burning lime in the unit located behind the roll-chamber. The unit for burning lime for KN as in example 1. By the beginning of the firing, 15.38 tons of limestone are loaded into the working mine. First, the gas phase is fed into the mine, which is formed in the KN during the roasting of lime. The temperature of the gas mixture is 1348°С, the time of this period is 6897 s. Then, a gas mixture is fed into the mine, which is formed when the melt is saturated with lime. The temperature of the gas mixture is 1640°C, the time is 1800 s. With a specific heat consumption for burning lime of 4.6 MJ/kg, 40.5 GJ of heat is required to burn the indicated portion. That is how much heat comes from the KN to the firing shaft. Thus, during the production cycle (9841 s) it is possible to obtain 8.81 tons of lime in the working mine for KH. Part of the lime is used in the desulfurization of off-gases and the production of gypsum, and the rest is sold to third-party consumers.

Compositions of the resulting products

Table 20 - Compositions of secondary resources with thermal power plants as part of the ETC

ΣFeO _{SiO2 Al2O3 _} CaO MgO _{Na2O K2O TiO2} S C TPP slag 14.41 54.36 26.01 2.20 1.04 0.32 0.64 1.02 0.00 0.00 Fly ash TPP 1.50 5.64 2.70 0.23 0.11 29.62 59.26 0.11 0.00 0.83

Table 21 - Composition of secondary resources from reduction smelting

ΣFeO _{SiO2 Al2O3 _} CaO MgO _{Na2O K2O TiO2} ZnO S C Slag 0.10 6.01 77.25 6.53 3.09 1.33 2.65 3.02 0.00 0.02 0.00 Dust 6.36 23.99 11.48 0.97 0.46 12.73 25.47 0.45 0.00 0.39 17.70

Table 22 - Composition of ferroalloy FS75 GOST1415-63

Fe Si Mn S P C 30.77 69.20 0.001 0.01 0.01 0.01

Table 23 - The composition of the aluminous clinker melt HZ according to GOST 969-91

_{Fe2O3 _ SiO2 Al2O3 _} CaO MgO MNO _{Na2O K2O TiO2} SO _{3 P2O5 _} 5.59 6.70 41.07 41.04 1.66 0.00 0.71 1.42 1.60 0.20 0.01

Table 24 - The composition of the gas mixture with TPP after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 23.79 0.00 16.22 4.23 55.76

Table 25 - The composition of the gas mixture from the roll-chamber saturation after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 83.22 0.00 12.95 0.00 3.83

Results obtained during the implementation of the method

Thus, as a result of the operation of the ETC during the production cycle (9841 s), 58230 kWh of electricity are obtained [7. GOST 32144-2013 Power quality standards in general purpose power supply systems. - M.: "Standartinform", 2014. - 16 p.]. At the same time, 32,946 kWh (56.6%) are released into the energy system, and 25,284 kWh (43.4%) of energy is consumed within the ETC. In addition, 51.00 tons of dump slag are processed in one production cycle, obtaining 16.92 tons of ferrosilicon FS70 [8. GOST 1415-93 Ferrosilicon. Technical requirements and terms of delivery. - Minsk: Interstate Council for Standardization, Metrology and Certification, 1993 - 14 p.] and 31.64 tons of aluminous cement HZ [9. Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.].

Example 3

Let us consider a special case of the implementation of example 2, when a complex oxidizer is used to burn the organic part of coal at TPPs, which includes technical oxygen and a gas body filler (NGT). The composition of the gas body filler is shown in Table 26.

Table 26 - Composition of the filler gas body vol.%.

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

Table 27 shows the duration of the TRC and shows the technological parameters that characterize the energy of the dusty gas phase entering the furnace of the TPP from the CP.

Table 27 - Time of the fuel dispenser and parameters of the VER at the exit from the CP

1-0 1-1 3-1 Cycle Mode time, s 228 8688 904 9820 ε _CO %* 99 99 100 99 Gas rate from gearbox, С 1673 1673 0 1673

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

The time of the metallurgical (production) cycle is 9820 s (2.73 h).

Table 28 shows the material balances for the respective TEC TPPs.

Table 28 - Material balances at the respective TEC TPPs

Oxygen (T=26°C) and gas body filler (T=350°C) are fed through separate channels, and their mixing takes place directly in the boiler furnace. The composition of the gas mixture leaving the TPP boiler after dedusting and desulfurization is shown in Table 29.

Table 29 - The composition of the gas mixture with TPP after desulfurization, vol.%

_{CO2 SO2 H2O O2} N ₂ 86.95 0.00 11.40 0.00 1.65

Table 30 shows the main technological parameters of the TPP operation during the entire production cycle.

Table 30 - Technological parameters of TPP operation

1-0 1-1 3-1 b (g/kWh)* 271 222 320 Steam capacity, t/h 82.01 82.02 82.00 Steam temperature, C 535 535 535 Steam pressure, MPa 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 MWt with steam. At the same time, in one production cycle (9820 s), the TPP generates 58100 kWh, using an average of 232 g of reference fuel per kWh.

Recovery stage of melting (production of ferrosilicon)

Reduction melting is carried out as in example 2.

Saturation of the slag melt with lime in KN

The saturation of the slag melt with lime is carried out as in example 2. However, in order to reduce the nitrogen content in the exhaust gas from the KH, the fuel is burned in oxygen. Table 31 shows the material balance of lime roasting in KN.

Table 31 - Material balance of lime roasting in KN

Income, t/pl. Consumption, t/pl. Limestone 22.30 Lime 13.24 Coal grade "T" 4.37 gas phase 21.91 Those. oxygen 8.81 Dust 0.33 Total: 35.48 Total: 35.48

Table 32 shows the material balance of saturation of the aluminous melt with lime.

Table 32 - Material balance of saturation of the melt with lime

Income, t/pl. Consumption, t/pl. Lime 13.24 Clinker 31.01 Slag from KP 16.11 gas phase 1.06 Iron ore 2.00 Dust 0.31 Coal grade "T" 0.34 Total: 32.38 Those. oxygen 0.69 Total: 32.38 Balance discrepancy, % 0.00

The total time of the stage, including the burning of lime in KN, the saturation of the melt with lime and the release of alumina clinker, is 9012 s.

The resulting clinker melt is poured into molds and sent to a site for controlled cooling.

Lime firing per KN

The flue gases generated during the saturation process are used for burning lime in the mines located behind the saturation chamber. By the beginning of firing, 15.35 tons of limestone is in the working shaft. First, the gas phase is fed into the mine, which is formed in the KN during the roasting of lime. The temperature of the gas mixture is 1380°C, the time of this period is 6612 s. Then, a gas mixture is fed into the mine, which is formed during the saturation of the slag melt. The temperature of the gas mixture is 1660°C, the time is 1800 s. With a specific heat consumption for burning lime of 4.6 MJ/kg, 40.46 GJ of heat is required to burn the indicated portion. That is how much heat comes from the SC to the firing shaft. Thus, during the production cycle (9820 s) in the working mine, 8.80 tons of lime can be obtained for KH. Part of the lime 0.29 tons is used in the purification of TPP gases from SO ₂ . The rest of the lime, 8.51 tons, is shipped to third-party consumers. Table 33 shows the average composition of the gas mixture leaving the saturation roll chamber and the roasting shaft during the production cycle.

Table 33 - Composition of the gas mixture from the saturation roller chamber, vol.%

_{CO2 SO2 H2O O2} N ₂ 93.68 0.00 5.94 0.00 0.38

The data presented show that combustion of fuel in oxygen makes it possible to obtain a gas mixture with a low nitrogen content. This gas mixture is considered a "clean gas" and is used in the formation of CPG without purification.

Preparation of gas body filler and production of CO ice ₂

The technological scheme for the preparation of the filler of the gaseous body and the production of dry ice is shown in Fig. 2. During the cycle (9820 s), 264.53 tons of gas from the thermal power plant and 29.50 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 257.64 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 27.92 Gas body filler 153.50 Gas. mixture with TPP "without purification" 48.60 Condensate 0.00 Gas. mixture with TPP "after cleaning" 75.43 Total: 153.50 water vapor 1.54 Total: 153.49 Discrepancy, % 0.007

Thus, all gas with OC and 48.60 tons of gas from TPPs is sent to the NGT without treatment. In addition, 1.54 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 26), 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 (190.08) 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: 72.22 tons of liquid oxygen, 4.02 tons of liquid argon and 231.60 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 (example 2) 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 pre-cooling stage, the gas mixture to be purified is cooled by nitrogen, oxygen and argon, which have passed into the gas phase in the process of ice production. At the first stage, in heat exchanger 7 (see Fig. 2), the mixture is cooled to a temperature of 273 K. As a result, it is transferred to condensate and 2.94 t H ₂ O are removed. ), the gas mixture to be purified is cooled to a temperature of 195 K. At this stage of pre-cooling, 0.48 t of excess components (remains of H ₂ O and SO ₂ ) are separated from the gas mixture into the solid phase. At the phase transformation stage (obtaining ice), the gas mixture to be purified is divided into two portions. The first portion of 127.49 tons is sent for cooling with liquid nitrogen, and the second 59.17 tons for cooling with liquid oxygen and argon.

The first portion is compressed in the compressor 11 to 0.19 MPa, 196.90 tons of liquid nitrogen are introduced into it and sent to the expander 12. In this case, the thermodynamic system "purified gas - 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 13 (see Fig. 2), and secondary nitrogen with a temperature of T _wN =194 K is removed, taking with it nitrogen and oxygen from the gas mixture being purified. Part of the secondary nitrogen removed from the expander chamber, 138.90 tons, is sent to recuperative heat exchangers 14 and 15 (see Fig. 2), 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 (59.17 t) is compressed in the compressor 11 to 0.16 MPa, 138.90 t of cooled secondary nitrogen and 34.74 t of liquid nitrogen are introduced into it and sent to the expander 12. This forms the thermodynamic system “the gas mixture being cleaned - 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 13, 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 the expanders, 12 electric generators produce 2847 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, 235.09 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, 183.13 tons of dry ice are obtained. At the same time, 107.70 tons of ice are sent by rail for further processing, and 75.43 tons are thawed in a special installation and used in the formation of NHT. To do this, dry ice from warehouse 16 (see Fig. 2) is introduced through lock 17 into sublimation chamber 18, where it turns into gas, cooling water from the TPP condenser. By adjusting the supply of ice, an excess pressure of 3.0 MPa is created in the sublimation chamber. Further, carbon dioxide, through the heat exchanger 19, enters the turbine of the electric generator 20, where it performs work, producing 1806 kWh of electricity. Electricity is used within the framework of the ETC, and 75.43 tons of CO ₂ enters the mixing gas tank 6, where the NGT is formed.

During the production cycle 9820 s (2.73 h) in the gas tank 6 accumulates the resulting gas mixture, which is fed into the mixing heater 21, where it is injected with 1.54 tons of water vapor at a temperature of 300°C. As a result, (153.5 t) NGT of a given composition (see Table 26) with a temperature of 31°C is obtained, which is fed into the heater of the TPP boiler.

Table 35 shows the balance of electricity in carbon neutral (example 3) and carbon positive (example 2) during the production cycle.

Table 35 - Electricity balance in ETC ROLMELT, during the cycle

Name of balance sheet items Example 3 Example 2 Receipt articles Produced by energy at TPPs, kWh 58100 58230 Produced by energy on expanders, kWh 2847 0 Produced by energy during ice defrosting, kWh 1806 0 Total: 62753 58230 Expenditure items For operation of TPP, kWh 3486 3494 For waste slag preparation, kWh 1699 1699 For the production of oxygen for technological. subsystems, kWh 29770 16990 For the production of oxygen for energy. subsystems, kWh 10560 0 For compressing gas mixtures before expanders, kWh 2497 0 For cement production, kWh 3101 3101 Electricity sent to the UES, kWh 11640 32946 Total: 62753 58230

The given data show that in example 3, 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 3, 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 (10560+2497)-(2847+1806)=8404 kWh. If this energy is related to the mass of CO ₂ formed in the ETC (257.64 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 0.117 GJ/t CO ₂ , and if we take into account here the costs incurred by metallurgical production, obtaining more energy-intensive oxygen, then it will increase to 0.295 GJ/t CO ₂ .

Results obtained during the implementation of the method

Thus, for 9820 (2.73 hours), 51.00 tons of prepared ash and slag are processed. At the same time, 16.92 tons of ferrosilicon (FS70 GOST1415-93), 31.64 tons of aluminous cement (GC GOST969-91) and 62753 kWh of electricity are produced. Moreover, 51,113 kWh of electricity is used within the ETC, and 11,640 kWh of carbon-neutral electricity (18.55%) is sent to third-party consumers in the UES. In addition, 107.70 tons of dry ice are sent to consumers.

Example 4

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 3). For this, the power of the TPP will be increased from 21.3 MW to 50 MW. 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 21.30 25.00 30.00 40.00 45.00 47.00 50.00 Share of the energy subsystem in the ETC, c.u. 0.262 0.293 0.311 0.331 0.395 0.435 0.505 Energy consumption for CO ₂ desublimation, GJ/t CO ₂ 0.295 0.274 0.265 0.258 0.252 0.264 0.318

The share of the energy or technological subsystem 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 0.252 GJ/t CO ₂ is achieved when the power of the TPP is 45 MW.

Brief description of the drawings

On FIG. 1 shows a graph of the change in gas flow in the outlet channel of the chamber during reduction melting, from the beginning of the introduction of charge materials to the release of products. The graph is a trapezoid ABCD. τ2 is the time of supply of charge materials. 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 τ1 is the time it takes to reach the normal melting mode. ВС=τ3 - operating time in normal melting mode. It is defined as the difference τ2 - τ1. The height of the trapezoid q _g - second gas flow through the outlet channel in the normal mode of melting. This flow rate is constant, since in the normal mode, the exhausted coal particles are replaced by newly introduced into the chamber. The angle of inclination of the side CD characterizes the decay rate of the reduction processes in the chamber after the supply of charge materials is stopped, and τ4 is the decay time of the process. If during the melting process the fractional and grade composition of the reducing agent does not change, then τ1=τ4, and the trapezoid ABCD is isosceles. The base of the trapezoid AD=τ5=τ2+τ1 is the total melting time, from the beginning of the material supply to the release of products. The area of the trapezoid is equal to the gas flow rate through the discharge channel for melting V _g , the Gas flow rate is determined from the material balance of the melting.

On FIG. Figure 2 shows a schematic flow diagram for the preparation of NGT and cryogenic cleaning of flue gases within the framework of the ETC.

Flue gases from TPP 2 and cement production 3 (clean gas) are supplied for processing. The gas phase from the TPP is sent to the gas tank 4, and from the cement production - to the gas tank 5. At the same time, part of the gas from the TPP (gas without purification) and the main part of the pure gas are sent to the mixing gas tank 6, where the composition of the CNG is formed. The rest of the gas from the TPP from the gas holder 4 is sent for cryogenic cleaning (gas for cleaning).

At the first stage of pre-cooling in the heat exchanger 7, water condensate is removed from the gas mixture. The temperature of the gas mixture in the heat exchanger 7 - T _cm ≥ 273K. In the second stage of pre-cooling in the heat exchangers 8, 9 and 10, the remaining H ₂ O and SO ₂ are separated as they pass into the solid phase. The temperature of the gas mixture during this period is in the range of T _cm =(273-195) K. Thus prepared, 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 distillation, namely liquid nitrogen, liquid oxygen and liquid argon, are used as coolants. 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 the compressor 11, liquid nitrogen is introduced into it and sent to the expander 12. The solid phase formed in the expander (dry ice) and secondary nitrogen (gas) enter the settling chamber of the expander 13, where dry ice (CO ₂ ) is retained , and secondary nitrogen with a temperature of T _wN =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 13 is cooled in recuperative heat exchangers 14 and 15. 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 11 and sent to the expander 12. , dry ice (CO ₂ ) and new secondary nitrogen (gas) are formed. Dry ice is retained in the settling chamber of the expander 13, and secondary nitrogen with a temperature of T _WN =194 K is removed from the chamber, taking with it nitrogen and oxygen 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 16. One portion of the ice to be sublimated is first sent to heat exchanger 7, where it changes its state of aggregation, cooling the gas mixture supplied for cleaning, and then to mixing gas holder 6, where CNG is formed . Another portion of ice is fed through lock 17 to sublimation chamber 18, where it changes its state of aggregation, cooling water from the TPP condenser. By adjusting the supply of ice, excess pressure is created in the sublimation chamber. High-pressure gas from the chamber 18 is heated in the heat exchanger 19 and performs work by rotating the turbine of the electric generator 20. 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 6, where the gas turbine is formed.

The flow rate of gas mixtures used in the formation of CPG is regulated in such a way that the nitrogen content in the resulting composition does not exceed the allowable value. The resulting gas mixture from the gas holder 6 is fed to the TPP boiler through the mixing heater 21, 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.

List of sources used

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4. Butt Yu.M., Okorokov S.D., Sychev M.M., Timashev V.V. Technology of binders: a textbook for universities / ed. Yu.M. Butta - M .: "Higher School", 1968. - 620 p.

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9. GOST 969-91 Aluminous and high aluminous cements. Specifications. - M.: "Standartinform", 2007. - 6 p.

Claims (6)

1. A method for the production of electricity, ferrosilicon and aluminous cement in one energy-technological complex, including burning the organic component of the fuel in a boiler of a thermal power plant to obtain a radiating gas body, transferring thermal energy from the gas body to water, obtaining water vapor and converting steam energy into electrical energy on thermal power plants, and the processing of the mineral component of the fuel in the form of molten slag and ash in roll chambers, and first slag melt and ash are fed into the melting roll chamber, their liquid-phase reduction is carried out to obtain ferrosilicon and molten slag, which is then fed into the saturation roll chamber, containing burnt lime, and saturate it with lime to obtain an aluminous clinker melt, while finishing processing of ferrosilicon and aluminous clinker is carried out outside the roll chambers by pouring and cooling, while choosing the cooling mode of the clinker melt they are prepared in such a way as to obtain a given mineralogical composition of alumina clinker, and a cement mixture is formed from cooled alumina clinker and technological additives and cleaned of metal inclusions in the process of its selective grinding and air separation, while the dust-gas phase from the melting roll-chamber is burned in the boiler thermal power plant, and the combustion of the organic component of the fuel is carried out in accordance with the combustion mode of the boiler, ensuring constant regular operation of the turbine of the electric generator, while the combustion mode of the boiler determines the consumption of the main fuel, auxiliary fuel - the dust-gas phase from the melting roll-chamber and the oxidizer, and the dust-gas mixture from Saturation roll-chambers are used as a heat carrier for lime calcination behind the saturation roll-chamber, while all gas mixtures formed during the implementation of the method are dedusted and subjected to desulphurization after their use. 2. The method according to claim 1, characterized in that the gas-cooler and corrective additives are additionally supplied to the boiler of the thermal power plant to adjust the content of CaO, FeO, SiO ₂ and Al ₂ O ₃ in the slag melt, and their consumption is determined by the combustion mode of the boiler . 3. The method according to claim 1 or 2, characterized in that the liquid-phase reduction of ferrosilicon additionally uses dust, melted slag, scrap metal and man-made waste from ash and slag dumps. 4. The method according to any one of claims 1-3, characterized in that when burning the organic component of the fuel, 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 flow rate, 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. 5. The method according to any one of claims 1 to 4, characterized in that the gas mixtures formed during the implementation of the method after dedusting and desulfurization are used as a gas body filler, for this, excess nitrogen is removed from them and the missing water is introduced. 6. The method according to claim 4 or 5, characterized in that part of the gas mixtures formed at a thermal power plant after dedusting and desulfurization is subjected to cryogenic cleaning to obtain dry ice, while one part of the resulting ice is subjected to sublimation and used in the preparation of a gas body filler, and the other is sent to consumers or accumulated in storage facilities, while the products of cryogenic air rectification and the sublimated part of the ice are used to cool the cleaned gas mixtures, 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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