Tail gas waste heat power generation equipment and tail gas waste heat power generation method

Abstract

The invention discloses tail gas waste heat power generation equipment which comprises waste gas power generation equipment and waste heat power generation equipment, the waste gas power generation equipment is used for recycling electric furnace gas generated by a closed silicomanganese furnace and generating power, the waste gas power generation equipment comprises a gas-fired boiler, and a gas cabinet, a gas heater and an electric furnace waste heat boiler are arranged on the gas inlet side of the gas-fired boiler; the gas heater is arranged in a flue of the gas-fired boiler; the waste heat power generation equipment is used for recycling waste heat of the sintering equipment and generating power. The waste heat power generation equipment comprises an electric furnace waste heat boiler, a first steam collecting box and a second steam collecting box. The invention further discloses a tail gas waste heat power generation method. According to the method, the technological characteristics of iron alloy smelting and sintered ore preparation are effectively utilized, and the residual gas of iron alloy preparation, the residual heat of the electric furnace and the residual heat of sintered ore preparation are fully utilized.

Description

Technical Field

[0001] This invention belongs to the field of thermal power generation technology, specifically relating to a waste heat power generation equipment and method for waste heat power generation. Background Technology

[0002] Ferroalloy smelting is an energy-intensive process, and ferroalloy products are mainly used in steelmaking. The closed ferrosilicon-manganese furnace is a new type of ferroalloy smelting equipment, characterized by its fully enclosed structure, DC power supply technology, and automated control system. The furnace gas temperature in the closed ferrosilicon-manganese furnace is high, exceeding 850℃, and CO accounts for 70%-75% of the furnace gas composition. This furnace gas has a high calorific value, approximately 8791-10884 kJ / m³, which is advantageous given the small furnace gas volume and high calorific value.

[0003] The sintering process provides refined iron ore raw materials for blast furnace ironmaking. With the increasing use of refined materials, the economic indicators of modern blast furnace production technology are constantly improving, making sintering an indispensable part of the steel production process. The sintering process involves mixing various fine-particle iron-containing raw materials with a certain proportion of flux and fuel, mixing them evenly in a mixer, granulating them, and then spreading them on a sintering machine for ignition. The ignited fuel generates high temperatures and undergoes a series of physicochemical reactions. Under these conditions, the fusible substances in the mixture soften and melt, and the resulting molten material wets and binds the unmelted large particles of ore. During the cooling process, the sinter gradually agglomerates into blocks, ultimately yielding sintered ore in block form. This entire process is called sintering.

[0004] Ferroalloy smelting and sinter preparation consume a lot of energy. Effectively utilizing the furnace gas generated by the closed ferrosilicon furnace and recovering the heat generated in the sintering process is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a waste gas heat power generation equipment and a waste gas heat power generation method, which effectively utilizes the process characteristics of ferroalloy smelting and sinter preparation, and makes full use of the waste gas from ferroalloy preparation, the waste heat from electric furnaces, and the waste heat from sinter preparation.

[0006] To achieve the above objectives, the technical solution used in this invention is: Waste gas power generation equipment includes: waste gas power generation equipment and waste heat power generation equipment, wherein... Waste gas power generation equipment is used to recover and utilize electric furnace gas generated by a closed ferrosilicon furnace and generate electricity. The waste gas power generation equipment includes: a gas boiler, a gas holder, a gas heater, and an electric furnace waste heat boiler on the gas inlet side of the gas boiler. The gas heater is connected to the outlet side of the gas holder through a gas pipeline. The gas heater is connected to the furnace burner of the gas boiler through a gas pipeline. The gas heater is arranged in the flue of the gas boiler. The inlet of the gas holder is connected to the flue gas outlet of the electric furnace waste heat boiler through a gas pipeline. Waste heat power generation equipment is used to recover waste heat from sintering equipment and generate electricity. The equipment includes: an electric furnace waste heat boiler, a first steam collection box, a second steam collection box, and a waste heat recovery boiler. The electric furnace waste heat boiler recovers waste heat from the electric furnace gas and is connected to the inlet side of the gas holder via a gas pipeline. The flue gas inlet of the electric furnace waste heat boiler is connected to the flue gas outlet of the sealed ferrosilicon furnace via a gas pipeline. The first and second steam collection boxes are used for steam-water separation. The inlet of the second steam collection box is connected to the steam outlet of the waste heat recovery boiler via a steam pipeline, and the outlet of the second steam collection box is connected to the steam inlet of the first steam collection box via a steam pipeline. The steam outlet of the first steam collection box is connected to the waste heat turbine via a steam pipeline, and the steam outlet of the electric furnace waste heat boiler is connected to the inlet of the first steam collection box via a steam pipeline. The waste heat recovery boiler is connected to the flue of the sintering machine via an induced draft pipe.

[0007] Furthermore, a dust collector is connected between the electric furnace waste heat boiler and the gas holder. The gas holder is used to temporarily store the electric furnace gas. The gas holder is equipped with an air intake pump at the inlet to introduce the electric furnace gas into the gas holder and keep the sealed ferrosilicon furnace side under negative pressure. The gas holder is equipped with a gas pump at the outlet to pressurize the output electric furnace gas.

[0008] Furthermore, the gas holder is connected to a gas heater via a gas pipeline. The gas heater is used to recover heat from the flue gas and is also connected to the furnace burner via a gas pipeline.

[0009] Furthermore, the waste heat power generation equipment includes: an electric furnace waste heat boiler, a waste heat recovery boiler, a waste heat turbine, a waste heat generator, and auxiliary equipment; the steam generated by the electric furnace waste heat boiler and the waste heat recovery boiler is sent to the waste heat turbine to do work, and the waste heat turbine drives the auxiliary generator to rotate and generate electricity.

[0010] Furthermore, the electric furnace waste heat boiler adopts a heat pipe waste heat boiler, the waste heat recovery boiler adopts a horizontal heat pipe boiler, the dust collector adopts a bag dust collector, the gas holder is used to buffer the impact force of the electric furnace gas, and the outlet and inlet of the first steam box and the second steam box are located at the top.

[0011] Waste heat power generation methods include: Electric furnace gas generated by a closed ferrosilicon furnace is transported to an electric furnace waste heat boiler via a gas pipeline. The waste heat boiler exchanges heat with the electric furnace gas to produce second steam, which is superheated steam. The second steam is sent into the first steam collection box. The electric furnace gas after cooling and dust removal is sent into a gas holder. The electric furnace gas in the gas holder is sent into a gas boiler to prepare first steam. The first steam is heated by a heat exchanger and then sent to the main steam turbine. The main steam turbine drives the main generator to generate electricity. The waste heat from sintering in the sintering machine is used to prepare the third steam, which is saturated steam. After being heated by the superheater in the sintering section, the third steam forms superheated steam, which is sent into the first steam collector. The first steam collector outputs superheated steam to the waste heat turbine, which drives the auxiliary generator to generate electricity.

[0012] Preferably, the furnace burner of the gas-fired boiler burns electric furnace gas, and the first steam generated by the gas-fired boiler is heated by a heater and then sent to the steam turbine, which drives the generator to rotate and generate electricity.

[0013] Preferably, the electric furnace waste heat boiler is connected to the flue gas duct before the electric furnace gas enters the flue gas settling cooler via a gas pipeline. The gas is led out from the flue gas settling cooler through an opening, and a blind flange valve and a triple eccentric sealing butterfly valve assembly are added at the opening. The temperature of the electric furnace gas entering the electric furnace waste heat boiler is 400-550℃. After exiting the electric furnace waste heat boiler, the electric furnace gas is discharged from the flue gas outlet at a temperature below 140℃. The electric furnace gas coming out of the gas holder is sent to the gas heater through a gas pipeline to raise the gas temperature to above 160℃. After being pressurized, it is then sent to the furnace burner of the gas boiler through a gas pipeline.

[0014] Preferably, the waste heat boiler in the sintering section is connected to the high-temperature zone of the sintering machine via an induced draft duct. The high-temperature zone of the sintering machine's sintering section is isolated from the low-temperature zone flue inside the duct by a blind flange valve. After hot air is drawn out, it enters the waste heat boiler in the sintering section through the induced draft duct. The flue gas at 250-280℃ is cooled to below 160℃ after heat exchange in the waste heat boiler in the sintering section and then enters the main flue. The waste heat boiler in the sintering section is connected to the outgoing bypass duct. The waste heat boiler in the cooling section is connected to the high-temperature zone of the sintering machine's cooling section via an induced draft duct. The high-temperature zone of the sintering machine's cooling section is isolated from the low-temperature zone flue inside the duct by a blind flange valve. After hot air is drawn out, it enters the waste heat boiler in the cooling section. The flue gas at 280-320℃ is cooled to below 160℃ after heat exchange in the waste heat boiler in the cooling section and then enters the main flue. The waste heat boiler in the cooling section is connected to the outgoing bypass duct.

[0015] Preferably, the saturated steam from the sintering section waste heat boiler and the cooling section waste heat boiler enters the second steam collector for merging and steam-water separation. The saturated steam is heated to 220°C by the superheater to form superheated steam, which is then transported to the first steam collector through the steam pipeline to power the waste heat turbine. The superheated steam generated by the sintering cooling section, the high-temperature section, and the electric furnace waste heat boiler is merged in the first steam collector and then sent to the waste heat turbine. The steam that has done work is condensed from the waste heat turbine and then pumped to the deaerator for deoxygenation. After deoxygenation, the boiler feed water pump supplies the recovered waste heat boiler for recycling, thus completing the steam-water cycle.

[0016] The technical effects of this invention include: This invention effectively utilizes the technological characteristics of ferroalloy smelting and sinter preparation, making full use of the waste gas from ferroalloy preparation and the waste heat from electric furnaces, as well as the waste heat from sinter preparation, to achieve continuous and efficient power generation through complementary power output, thereby reducing the overall energy consumption index of production.

[0017] This invention can effectively utilize the electric furnace gas generated during ferroalloy smelting and make full use of the waste heat of the high-temperature electric furnace gas to directly produce superheated steam. This not only reduces the overall energy consumption of ferroalloy preparation, but also reduces the environmental impact of high-energy-consuming production and high-temperature flue gas, and reduces the emission of harmful gases.

[0018] This invention can effectively utilize the waste heat generated in the medium-high temperature and low temperature sections of sinter preparation, realize the conversion of saturated steam into superheated steam, achieve full recovery and utilization of sinter waste heat, and reduce the overall energy consumption of the sintering process. Attached Figure Description

[0019] Figure 1 This is a flow chart of the tail gas power generation process in this invention; Figure 2 This is a flow chart of the exhaust gas power generation process in this invention. Detailed Implementation

[0020] The following description fully illustrates specific embodiments of the present invention to enable those skilled in the art to practice and reproduce it. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] The specific steps for generating electricity from waste heat from exhaust gas are as follows: like Figure 1 The diagram shown is a flow chart of the exhaust gas power generation process in this invention.

[0024] Step 1: The electric furnace gas generated by the closed ferrosilicon furnace is transported to the electric furnace waste heat boiler (heat pipe waste heat boiler) through a gas pipeline. The electric furnace waste heat boiler exchanges heat with the electric furnace gas to generate second steam, which is superheated steam. The second steam is sent into the first steam box. The electric furnace gas after cooling and dust removal is sent into the gas holder. The electric furnace gas in the gas holder is sent into the gas boiler to prepare the first steam. The first steam is heated by the heat exchanger and then sent to the main steam turbine. The main steam turbine drives the main generator to generate electricity. Waste gas power generation equipment includes: waste gas power generation equipment and waste heat power generation equipment.

[0025] Waste gas power generation equipment is used to recover and utilize the electric furnace gas generated by the closed ferrosilicon furnace and generate electricity. Waste gas power generation equipment includes: gas boiler, main steam turbine, main generator and other auxiliary equipment.

[0026] The gas boiler, main steam turbine, main generator and other auxiliary equipment are obtained through market procurement. This invention improves the gas inlet and outlet side equipment (gas holder, gas heater, electric furnace waste heat boiler) of the gas boiler.

[0027] The gas boiler has a gas holder, a gas heater, and an electric furnace waste heat boiler added to the gas inlet side. The electric furnace waste heat boiler is connected to the inlet side of the gas holder through a gas pipeline, and the gas heater is connected to the outlet side of the gas holder through a gas pipeline. The flue gas inlet of the electric furnace waste heat boiler is connected to the flue gas outlet of the sealed ferrosilicon furnace through a gas pipeline. A dust collector (bag filter) is connected between the electric furnace waste heat boiler and the gas holder. The gas heater is connected to the furnace burner of the gas boiler through a gas pipeline.

[0028] The gas holder is used to temporarily store electric furnace gas. The gas holder is equipped with an air intake pump at the inlet, which is connected to the flue gas outlet of the electric furnace waste heat boiler through a pipeline. This pump is used to introduce the electric furnace gas into the gas holder and keep the sealed ferrosilicon furnace side under negative pressure. The gas holder is equipped with a gas pump at the outlet, which is connected to the burner of the gas boiler through a pipeline. The gas pump is used to pressurize the output electric furnace gas.

[0029] The furnace burner of the gas-fired boiler burns gas from the electric furnace. The first steam generated by the gas-fired boiler is heated by the heater and then sent to the steam turbine, which drives the generator to generate electricity.

[0030] The electric furnace waste heat boiler (using a heat pipe waste heat boiler) recovers the heat from the electric furnace gas and generates second steam (superheated steam). The second steam is transported to the first steam box through a steam pipeline. The pressure of the second steam output by the electric furnace waste heat boiler is 0.8 MPa, the temperature is 220℃, and the flow rate is 3.5 t / h.

[0031] Electric furnace gas (raw coal gas, temperature 400-550℃, dust content 150g / m³) 3 After being cooled to 140℃ by the waste heat boiler of the electric furnace, the gas undergoes dust removal treatment. Following dust removal, the gas is then piped into a gas holder for subsequent gas-fired power generation. The gas holder buffers the impact force of the electric furnace gas, ensuring a stable supply (pressure and quantity) of gas for power generation, with a temperature below 70℃.

[0032] The gas holder is connected to a gas heater via a gas pipeline. The gas heater is located in the flue and is used to recover heat from the flue gas. The gas heater is also connected to the furnace burner via a gas pipeline. The electric furnace gas from the gas holder is sent to the gas heater via the gas pipeline to raise the gas temperature to 160°C. After being pressurized, it is then sent to the furnace burner of the gas-fired boiler via the gas pipeline. The combustion air of the gas-fired boiler is drawn in by a blower. The cold air is preheated by an air preheater and then sent to the hot air inlets of the furnace burner. The flue gas produced by the combustion of gas passes through the heat exchanger, economizer, air preheater, and gas heater before being drawn in by an induced draft fan and discharged into the atmosphere through a 40m high concrete chimney.

[0033] Auxiliary equipment includes: main superheater, economizer, air preheater, gas heater, and various pipeline pumps. The main superheater, economizer, air preheater, and gas heater are heat exchangers, usually installed at the furnace outlet.

[0034] The main superheater heats the saturated steam (generally containing 2% moisture) output from the gas boiler to superheated steam at a specified superheating temperature, providing power to the main turbine generator. The economizer, air preheater, and gas heater are components for recovering heat from the flue gas.

[0035] like Figure 2 The diagram shown is a process flow chart of waste heat power generation in this invention.

[0036] Step 2: The waste heat from sintering in the sintering machine is used to prepare the third steam (saturated steam). The third steam is sent to the second steam collector through the steam pipeline. After being heated by the superheater in the sintering section, the third steam is sent to the first steam collector. The first steam collector outputs superheated steam to the waste heat turbine, which drives the auxiliary generator to generate electricity.

[0037] The first steam box is used to buffer and collect superheated steam, perform steam-water separation, and output stable superheated steam.

[0038] Waste heat power generation equipment includes: electric furnace waste heat boilers, waste heat recovery boilers, waste heat turbines, waste heat generators, and other auxiliary equipment. The steam generated by the electric furnace waste heat boilers and waste heat recovery boilers is fed into the waste heat turbine to perform work, and the waste heat turbine drives the auxiliary generator to generate electricity.

[0039] The electric furnace waste heat boiler, the waste heat recovery boiler, the waste heat turbine, the waste heat generator, and other auxiliary equipment can be obtained commercially. In this invention, the heat source and installation location of the electric furnace waste heat boiler and the waste heat recovery boiler have been improved. At the same time, a first steam box and a second steam box have been added. The first steam box and the second steam box are steam-water separation devices, with the outlet and inlet located at the top. The inlet of the second steam box is connected to the steam outlet of the waste heat recovery boiler through a steam pipeline, and the outlet of the second steam box is connected to the inlet of the first steam box through a steam pipeline. The outlet of the first steam box is connected to the waste heat turbine through a steam pipeline, and the outlet of the electric furnace waste heat boiler is connected to the inlet of the first steam box through a steam pipeline. The waste heat recovery boiler is connected to the flue of the sintering machine through an induced draft pipe.

[0040] The electric furnace waste heat boiler (heat pipe waste heat boiler) is connected to the flue gas duct before the electric furnace gas enters the flue gas settling cooler via a gas pipeline. An opening is provided before the gas enters the settling cooler, with a blind flange valve and a triple eccentric sealing butterfly valve assembly added at the opening to ensure no leakage of the electric furnace gas. The raw gas, at a temperature of 400-550℃, is cooled and enters the electric furnace waste heat boiler through the gas pipeline. After exiting the electric furnace waste heat boiler, the electric furnace gas is discharged through the flue gas outlet at a temperature below 140℃. After dust removal by the dust collector, it enters the gas holder. The generated second type of steam is superheated steam, which is transported to the first steam collection box through a steam pipeline.

[0041] Waste heat recovery boilers (using horizontal heat pipe boilers) include: sintering section waste heat boilers and cooling section waste heat boilers. Both sintering section waste heat boilers and cooling section waste heat boilers are selected as horizontal heat pipe boilers.

[0042] The waste heat boiler in the sintering section is connected to the high-temperature zone of the sintering machine via an induced draft duct. The high-temperature zone and the low-temperature zone of the sintering section are isolated internally by blind flange valves. Hot air is drawn out and enters the waste heat boiler through the induced draft duct. The 250-280℃ flue gas is cooled to 160℃ after heat exchange in the waste heat boiler and then flows into the original main exhaust duct. The boiler equipment is inserted into the bypass duct. The boiler's air resistance is below 300Pa, ensuring no impact on other systems. The waste heat flue gas volume is 58,000 m³ / h. 3 The sintering section waste heat boiler produces 2t / h of steam at 0.8MPa, and the steam is saturated steam.

[0043] The waste heat boiler in the cooling section is connected to the high-temperature zone of the sintering machine's cooling section via an induced draft duct. The high-temperature zone and the low-temperature zone of the sintering machine's cooling section are isolated internally by blind flange valves. Hot air is drawn out and enters the waste heat boiler in the cooling section. The 280-320℃ flue gas is cooled to 160℃ after heat exchange in the waste heat boiler and then enters the main cooling flue. The boiler equipment is inserted into the bypass duct. The boiler's air resistance is within 400Pa, ensuring it does not affect other systems. The waste heat flue gas volume is 120,000 m³. 3 / h, boiler steam production capacity 3.5t / h, 0.8MPa, saturated steam.

[0044] The saturated steam from the sintering section waste heat boiler and the cooling section waste heat boiler enters the second steam collector for merging and steam-water separation. The saturated steam is then heated to 220°C by a superheater to form superheated steam, which is then transported to the first steam collector via steam pipelines for subsequent power generation by the waste heat turbine. The sintering section waste heat boiler and the cooling section waste heat boiler share a single steam drum, a deaerator, and a soft water treatment system.

[0045] The superheated steam generated by the sintering cooling section, the high-temperature section and the electric furnace waste heat boiler is combined in the first steam box and sent to the waste heat turbine. The steam that has done work is condensed from the waste heat turbine and sent to the deaerator for deoxygenation by the condensation pump. After deoxygenation, it is supplied by the boiler feed water pump to the waste heat recovery boiler for recycling, thus completing the steam-water cycle.

[0046] Example 1 In this embodiment, the temperature of the raw gas is reduced by passing it through a heat pipe waste heat boiler before air cooling, generating 0.8MPa steam. This steam, along with the steam generated by the sintering waste heat boiler, is used to generate electricity. After the waste heat is utilized, the flue gas is cooled to 140°C and then treated for dust removal before entering the gas holder for subsequent gas power generation.

[0047] The high-temperature flue gas in the sintering section of the sintering machine and the waste heat of the high-temperature flue gas in the cooling section are utilized to generate 0.8MPa steam for power generation.

[0048] The specific equipment used in this embodiment is shown in Table 1.

[0049] Table 1 Waste Gas Power Generation Equipment

[0050] Two high-temperature, high-pressure, natural circulation, balanced ventilation, gas-fired (sealed ferrosilicon manganese furnace tail gas) electric furnace waste heat boilers (heat pipe waste heat boilers) with an evaporation capacity of 75t / h are configured. The model is RG3.5t / h-0.8, with an evaporation capacity of 2.5t / h and a pressure of 0.8MPa. Details are shown in Table 2.

[0051] Table 2 Parameter Table for Electric Furnace Waste Heat Boiler

[0052] The boiler auxiliary configuration is shown in Table 3.

[0053] Table 3 Boiler Auxiliary Configurations

[0054] The main technical parameters of the two main steam turbines (18MW condensing steam turbines) are shown in Table 4.

[0055] Table 4 Technical Parameters of Main Steam Turbine

[0056] The main technical parameters of the two main generators (20MW air-cooled generators) are shown in Table 5.

[0057] Table 5 Technical Parameters of Main Generator

[0058] The two main generators each have a rated power of 20MW, and the auxiliary generator has a rated power of 2.5MW. The units are used for 8000 hours. Considering that the amount of flue gas generated by the calcining furnace will fluctuate within a certain range, and that the ferrosilicon furnace and sintering machine have certain maintenance cycles, the power generation is calculated based on the lower limit of waste heat and waste gas generation. Therefore, the annual power generation is 20 × 8000 × 0.8 × 2 + 2.5 × 8000 × 0.8 = 272 million kWh.

[0059] Waste heat recovery boilers include: sintering section waste heat boilers, cooling section waste heat boilers, and electric furnace waste heat boilers.

[0060] One waste heat boiler for the sintering section, model YG2t / h-0.8, with an evaporation capacity of 3.5t / h and a pressure of 0.8MPa. One waste heat boiler for the cooling section, model RG3.5t / h-0.8, with an evaporation capacity of 4.5t / h and a pressure of 0.8MPa. One waste heat boiler for the electric furnace, model RG3.5t / h-0.8, with an evaporation capacity of 2.5t / h and a pressure of 0.8MPa.

[0061] The auxiliary equipment for the waste heat boiler is shown in Table 6.

[0062] Table 6 Boiler Auxiliary Equipment Configuration Table

[0063] One waste heat turbine (N2.5-0.8 medium-temperature, medium-pressure condensing turbine). Technical parameters are shown in Table 7. Waste heat turbine Table 7 Technical Parameters of Waste Heat Turbine

[0064] The waste heat generator is a 2.5MW air-cooled generator, and its main technical parameters are shown in Table 8.

[0065] Table 8 Technical Parameters of Waste Heat Generator

[0066] The selection and technical parameters of the main auxiliary equipment are shown in Table 9.

[0067] Table 9 Auxiliary Equipment List

[0068]

[0069] Step 1: Generate electricity using gas from an electric furnace; After cooling and dust removal, the electric furnace gas is sent into the gas holder. The electric furnace gas in the gas holder is then sent into the gas boiler to prepare the first steam. The first steam is heated by the heater and then sent into the main steam turbine. The main steam turbine drives the main generator to generate electricity.

[0070] The combustion system, centered around a gas-fired boiler, includes components such as boiler gas delivery, gas pressurization, forced draft, and induced draft. The boiler uses electric arc furnace gas as fuel. The gas temperature is raised to 160°C by a gas heater before being piped to the furnace burners. Combustion air is drawn in by a forced draft fan, preheated in an air preheater, and then distributed to the hot air inlets of each burner. The flue gas produced by combustion passes through a preheater, economizer, air preheater, and gas heater before being drawn in by an induced draft fan and discharged into the atmosphere through a 40m high concrete chimney.

[0071] The main steam pipeline connects to the superheater via a hydrostatic test plugging valve and then to the main turbine's automatic main steam valve. The main steam pipeline also connects to branch steam, which, after desuperheating and pressure reduction, serves as an auxiliary steam source for the shaft seal self-sealing system during unit startup. To remove condensate from the main steam during startup warm-up and shutdown, an automatic drain point is installed at the lowest point of the main steam pipeline, with the drained water introduced into the turbine's drain expansion tank.

[0072] To shorten turbine start-up time and recover losses during startup, and to prevent potential reheater dry burning, a 25% high- and low-pressure bypass system is configured. The high-pressure bypass is connected to the main steam pipeline, undergoes pressure reduction and desuperheating, and then connects to the reheat cold section steam pipeline. The desuperheating water comes from the high-pressure feedwater system. The low-pressure bypass is connected to the reheat hot section steam pipeline, undergoes pressure reduction and desuperheating, and then connects to the condenser. The high- and low-pressure bypasses include steam control valves, desuperheating water control valves, shut-off valves, and control devices.

[0073] The function of the feedwater system is to pressurize the deoxygenated feedwater and send it to the boiler economizer, and to provide desuperheating water for the boiler superheater desuperheater.

[0074] The main steam turbine has five stages of regenerative extraction, which serve as the heating steam source for the second-stage low-pressure heater and the first-stage deaerator.

[0075] The condensate system uses a single-bus system. The unit is equipped with four 100% capacity condensate pumps (two in operation and two on standby) and two shaft seal heaters. Condensate is pumped into the shaft seal heaters by the condensate pumps, and then enters the deaerator via the low-pressure heater.

[0076] The drainage system is equipped with a continuous sewage discharge expansion container, a periodic sewage discharge expansion container, and a drainage expansion container, as well as a drainage tank and a drainage pump.

[0077] To ensure the safe and economical operation of the steam turbine generator set and to maintain a certain vacuum level in the condenser, two sets of water ring vacuum pumps (one for standby and one for use) are installed to ensure the unit starts up.

[0078] The circulating water pump lifts the cooling water from the circulating water pool and sends it to cooling equipment such as the condenser, oil cooler, and generator air cooler. The hot water discharged from the condenser, oil cooler, and other equipment is sent to the ventilation cooling tower through the pressure header and then enters the circulating water pool after being cooled by the cooling tower.

[0079] Step 2: Recover the waste heat from the electric furnace gas and generate electricity; The electric furnace gas generated by the closed ferrosilicon furnace is transported to the electric furnace waste heat boiler (heat pipe waste heat boiler) through a gas pipeline. The electric furnace waste heat boiler exchanges heat with the electric furnace gas to generate second steam, which is then sent into the first steam box.

[0080] The flue gas from the electric furnace is led out through an opening before entering the flue gas settling cooler. A blind flange valve and a triple-eccentric sealing butterfly valve assembly are added to the opening to ensure no leakage of the flue gas. The flow rate is 16000 m³ / h. 3 Raw coal gas with a temperature of 400-550℃ and a dust content of 150g / m3, is produced at a rate of approximately 1 / h. It enters the heat pipe waste heat boiler through a high-temperature pipe and is finally discharged from the flue at a temperature below 140℃. It then enters the dust collector and is sent to the gas holder to supply the subsequent electric furnace gas power generation.

[0081] Externally supplied soft water is pumped from the soft water tank into the deaerator for deoxygenation. The system uses a thermal deaerator. Deoxygenated steam is introduced from the boiler outlet. The deoxygenated water is then pumped into the electric furnace waste heat boiler by an electric feedwater pump, generating 2×3.5t / h, 0.8MPa, 220℃ superheated steam. This superheated steam is then combined with the sintering waste heat steam in the steam collector, resulting in a total of 15t / h of steam entering the second steam collector for subsequent waste heat power generation.

[0082] Step 3: Recover waste heat from sintering and generate electricity.

[0083] The high-temperature zone of the sintering section of the sintering machine (i.e., the main flue area corresponding to wind boxes 9, 10, and 11) is isolated from the low-temperature zone flue using blind flange valves. The flue gas is then led out and enters the bedroom heat pipe boiler. The 250-280℃ flue gas is cooled to 160℃ after heat exchange in the boiler and then flows into the original main exhaust flue. The boiler equipment is inserted into the bypass pipe. The boiler's air resistance is within 300Pa, ensuring no impact on other systems. The waste heat flue gas volume is 58,000 m³. 3 The boiler produces 2 t / h of steam at 0.8 MPa, and the steam is saturated steam.

[0084] The high-temperature zone of the sintering machine cooling section (i.e., the main flue area corresponding to wind boxes 12, 13, 14, 15, and 16) is isolated from the low-temperature zone flue using blind flange valves. The flue gas is then led out and enters the bedroom heat pipe boiler. The 280–320℃ flue gas is cooled to 160℃ after heat exchange in the boiler and then re-enters the original cooling flue main pipe. The boiler equipment is inserted into the bypass pipe. The boiler's air resistance is below 400Pa, ensuring no impact on other systems. The waste heat flue gas volume is 120,000 m³. 3The boiler produces 4.5 t / h of steam at 0.8 MPa, saturated steam. The saturated steam is combined with 3.5 t / h of steam from the sintering waste heat boiler in the second steam collector and then enters the superheater of the cold section waste heat boiler. The 5.5 t / h of saturated steam is superheated to 220°C and then sent to the first steam collector for subsequent power generation.

[0085] The sintering cooling waste heat boiler and the sintering waste heat boiler share a steam drum, a deaerator, and a soft water treatment unit.

[0086] The superheated steam from the sintering cooling section and the high-temperature section is combined with the steam generated by the electric furnace waste heat boiler in the steam collection box and then sent to the waste heat power plant for power generation. After condensation from the steam turbine, the steam is pumped to the deaerator for deoxygenation. After deoxygenation, the steam is supplied to the boiler by the boiler feed water pump, thus completing the steam-water cycle.

[0087] The generator terminal voltage is 10.5kV, and a grid-connected switchgear for the generator set is installed in the newly built generator room. There are two grid connection points: one at the generator outlet and the other at the 10kV port of the step-up transformer. The power plant's auxiliary power supply is drawn from the 10kV direct supply section.

[0088] The terminology used in this invention is descriptive and exemplary, not restrictive. Since this invention can be embodied in many forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A tail gas waste heat power generation apparatus, characterized by, The application relates to a residual gas power generation device and a residual heat power generation device. The residual gas power generation device is used for recycling electric furnace gas generated by a closed silicon-manganese furnace and generating power, and the residual gas power generation device comprises a gas-fired boiler, a gas cabinet, a gas heater, an electric furnace residual heat boiler, a gas inlet side of the gas-fired boiler is provided with the gas cabinet, the gas heater and the electric furnace residual heat boiler, the gas heater is connected to one side of an outlet of the gas cabinet through a gas pipeline, the gas heater is connected to a hearth burner of the gas-fired boiler through a gas pipeline, the gas heater is arranged in a flue of the gas-fired boiler, and a gas inlet of the gas cabinet is connected to a flue gas outlet of the electric furnace residual heat boiler through a gas pipeline. The residual heat power generation device is used for recycling residual heat of a sintering device and generating power, and the residual heat power generation device comprises an electric furnace residual heat boiler, a first steam collecting box, a second steam collecting box and a recycling residual heat boiler, the electric furnace residual heat boiler is used for recycling residual heat of electric furnace gas, is connected to one side of a gas inlet of a gas cabinet through a gas pipeline, and a flue gas inlet of the electric furnace residual heat boiler is connected to a flue gas outlet of a closed silicon-manganese furnace through a gas pipeline; the first steam collecting box and the second steam collecting box are used for steam-water separation, a water vapor outlet of the recycling residual heat boiler is connected to an inlet of the second steam collecting box through a steam pipeline, an outlet of the second steam collecting box is connected to an inlet of the first steam collecting box through a steam pipeline; a steam outlet of the electric furnace residual heat boiler is connected to an inlet of the first steam collecting box through a steam pipeline, and the recycling residual heat boiler is connected to a flue of a sintering machine through an air induction pipeline. A dust remover is connected between the electric furnace residual heat boiler and the gas cabinet, the gas cabinet is used for temporarily storing the electric furnace gas, a suction pump is arranged at an inlet of the gas cabinet and used for leading the electric furnace gas into the gas cabinet and keeping one side of the closed silicon-manganese furnace in a negative pressure state, and a gas pump is arranged at an outlet of the gas cabinet and used for pressurizing the output electric furnace gas.

2. The tail gas energy recovery power plant of claim 1, wherein, The gas cabinet is connected to the gas heater through a gas pipeline, the gas heater is used for recycling flue gas heat, and the gas heater is connected to the hearth burner through a gas pipeline.

3. The waste heat power generation apparatus according to claim 1, wherein The residual heat power generation device comprises the electric furnace residual heat boiler, the recycling residual heat boiler, a residual heat steam turbine, a residual heat generator and auxiliary equipment; water vapor generated by the electric furnace residual heat boiler and the recycling residual heat boiler is sent into the residual heat steam turbine to do work, and the residual heat steam turbine drives a secondary generator to rotate to generate power.

4. The waste heat power generation apparatus according to claim 1, wherein The electric furnace residual heat boiler adopts a heat pipe residual heat boiler, the recycling residual heat boiler adopts a horizontal heat pipe boiler, the dust remover adopts a bag dust remover, the gas cabinet is used for buffering the impact force of the electric furnace gas, and the outlets and inlets of the first steam collecting box and the second steam collecting box are arranged at the top.

5. The waste heat power generation apparatus according to claim 2, wherein The application relates to a residual gas power generation device and a residual heat power generation device.

6. The exhaust heat power generation method of the exhaust heat power generation apparatus according to any one of claims 1 to 5, characterized by, The electric furnace gas generated by the closed silicon-manganese furnace is transported to the electric furnace residual heat boiler through a gas pipeline, the electric furnace residual heat boiler exchanges heat with the electric furnace gas to generate second water vapor, the second water vapor is superheated water vapor, the second water vapor is sent into the first steam collecting box, the electric furnace gas after temperature reduction and dust removal is sent into the gas cabinet, the electric furnace gas in the gas cabinet is sent into the gas-fired boiler to prepare first water vapor, the first water vapor after heating by a heater sends superheated water vapor into a main steam turbine, and the main steam turbine drives a main generator to generate power. ​ Third water vapor is prepared by using sintering waste heat, the third water vapor is saturated steam, the third water vapor is heated by a superheater of a sintering section to form superheated water vapor, and the superheated water vapor is sent to a first steam collector, and the first steam collector outputs the superheated water vapor to a waste heat steam turbine, and the waste heat steam turbine drives a sub-generator to generate power.

7. The method of claim 6, wherein the exhaust gas is from a gas turbine engine. The first water vapor generated by the gas-fired boiler is heated by a heater and then sent to a steam turbine, and the steam turbine drives a generator to rotate and generate power.

8. The method of claim 6, wherein the exhaust gas is used to generate power. The electric furnace waste heat boiler is connected to the flue before the electric furnace gas enters the flue gas settling cooler through a gas pipeline, and is introduced at an opening before entering the flue gas settling cooler, and a blind plate valve and a three-eccentric sealing butterfly valve group are added at the opening; the temperature of the electric furnace gas entering the electric furnace waste heat boiler is 400-550 DEG C, and the temperature of the electric furnace gas discharged from the electric furnace waste heat boiler is below 140 DEG C; the electric furnace gas from the gas cabinet is sent to the gas heater through the gas pipeline to raise the temperature of the gas to above 160 DEG C, and after being pressurized, the gas is sent to the furnace burner of the gas-fired boiler through the gas pipeline.

9. The method of claim 6, wherein the exhaust gas is used to generate power. The sintering section waste heat boiler is connected to the high-temperature zone of the sintering section of the sintering machine through an air duct, the high-temperature zone of the sintering section of the sintering machine is separated from the low-temperature zone of the sintering section by a blind plate valve, hot air is introduced into the sintering section waste heat boiler through the air duct after being introduced, the temperature of the 250-280 DEG C flue gas is reduced to below 160 DEG C after being exchanged by the sintering section waste heat boiler, and then the flue gas is introduced into the main flue, and the sintering section waste heat boiler is connected to the bypass pipe; the cooling section waste heat boiler is connected to the high-temperature zone of the cooling section of the sintering machine through an air duct, the high-temperature zone of the cooling section of the sintering machine is separated from the low-temperature zone of the cooling section by a blind plate valve, hot air is introduced into the cooling section waste heat boiler, the temperature of the 280-320 DEG C flue gas is reduced to below 160 DEG C after being exchanged by the cooling section waste heat boiler, and then the flue gas is introduced into the main flue, and the cooling section waste heat boiler is connected to the bypass pipe.

10. The method of claim 6, wherein the exhaust gas is from a gas turbine engine. The saturated water vapor of the sintering section waste heat boiler and the cooling section waste heat boiler is combined in the second steam collector, steam and water are separated, the saturated water vapor is heated to 220 DEG C by a superheater to form superheated water vapor, and the superheated water vapor is transported to the first steam collector through a steam pipeline to generate power for the waste heat steam turbine; the superheated water vapor generated by the sintering cooling section, the high-temperature section and the electric furnace waste heat boiler is combined in the first steam collector and then sent to the waste heat steam turbine, the water vapor after work is condensed from the waste heat steam turbine and then sent to the deaerator in the deaerator for deaeration, and after deaeration, the water vapor is supplied by a boiler feed water pump to the waste heat recovery boiler for recycling, and the steam-water circulation is completed.

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