Converter flue gas full-dry cooling waste heat efficient recovery system and method

Abstract

The invention discloses a converter flue gas full-dry cooling waste heat efficient recovery system and method. The system comprises a converter flue gas pipe, a high-temperature flue gas dust removal device, a solid heat exchange tower, a dense pipe heat exchanger, a water pipe, a steam pipe, a power generator, a low-temperature flue gas dust removal device, a screening device, a bucket elevator, a gas chamber and solid particle balls. The solid heat exchange tower comprises a heat exchange chamber and a high-temperature bin, the heat exchange chamber is filled with solid particle balls, the dense tube heat exchanger comprises a rotary cylinder, a front-end sealing cover, a heat exchange tube, a rotary joint and a rear-end sealing cover, and the rotary cylinder is filled with the solid particle balls. And the high-temperature solid particle balls are used for heating the water in the rotary dense tube heat exchanger to convert the water into non-pressure steam, so that the steam is externally conveyed or power generation is carried out, and the method for treating the high-temperature flue gas of the converter has the advantage of high waste heat recovery rate.

Description

Technical Field

[0001] The present invention relates to the technology of high-temperature flue gas waste heat recovery, in particular to a system and method for efficiently recovering dry-cooled waste heat from high-temperature flue gas generated in the converter steelmaking process of iron and steel production enterprises. Background Art

[0002] China is a major industrial country. In recent years, China's annual crude steel output has exceeded 1 billion tons, accounting for more than half of the global output. Currently, China's iron and steel industry mainly uses the long-process production process of blast furnaces and converters, and the production capacity of short-process steelmaking such as electric furnaces is only about 10%. More than 90% of China's steelmaking production uses converters. There are more than 200 large-scale iron and steel enterprises in China, involving more than 900 converters. Taking the production and smelting of a 100-ton converter as an example, the hourly generation of high-temperature flue gas is about 70,000 Nm³, the initial temperature of the converter flue gas is about 1450 °C, the calorific value contained in the high-temperature flue gas generated per hour exceeds 120 GJ, which is equivalent to more than 20 kg of standard coal per ton of steel, and the recoverable pressurized steam per ton of steel exceeds 200 kg. Calculated on a national scale, China's steel output exceeds 1 billion tons, of which the waste heat resources exceed 20 million tons of standard coal, equivalent to an economic benefit of more than 20 billion yuan and a carbon emission reduction of more than 50 million tons. It can be seen that the recovery and utilization of converter flue gas waste heat has important economic and social value.

[0003] At present, China's high-temperature flue gas treatment often uses a hood and a waste heat boiler to recover the waste heat of high-temperature flue gas, convert the calorific value of high-temperature flue gas into pressurized steam, and then carry out utilization such as waste heat power generation. The existing process mainly uses the converter top hood to recover the waste heat of high-temperature flue gas above 900 °C, that is, the waste heat resources in the high-temperature section are recovered, equivalent to 80-100 kg of pressurized steam recovered per ton of steel, while the waste heat resources of flue gas below 900 °C are basically all wasted. The traditional process uses wet or evaporative cooling and other processes to treat this part of the flue gas, mainly using water as the cooling medium for treatment, resulting in the inability to recover and utilize the medium and low-temperature waste heat resources. The traditional process recovers the waste heat of high-temperature flue gas. Taking the waste heat energy recovery at 60% and the steam power generation energy efficiency conversion at 30% as an example, after deducting the waste heat dissipation of the low-temperature section flue gas, the overall waste heat utilization rate is only about 20%. Therefore, it can be seen that the waste heat utilization efficiency of high-temperature flue gas in the current industrial system is still at a relatively low level, and there is an urgent need to develop new waste heat recovery and utilization processes. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a converter flue gas all-dry cooling waste heat efficient recovery system and method, which can achieve efficient recovery of high-temperature flue gas waste heat.

[0005] To achieve the above object, the present invention adopts the following technical solution: A fully dry cooling and high-efficiency waste heat recovery system for converter flue gas, comprising a converter flue gas pipe, a high-temperature flue gas dust removal device, a solid heat exchanger tower, a dense tube heat exchanger, a water pipe, a steam pipe, a generator, a low-temperature flue gas dust removal device, a screening device, a bucket elevator, a gas holder, and solid particle balls; The solid heat exchanger tower includes a heat exchange chamber and a high-temperature bin. The heat exchange chamber is filled with solid particle balls. A feeding trough is arranged at the top of the heat exchange chamber, an air inlet is arranged below the side of the heat exchange chamber, an air outlet is arranged above the side of the heat exchange chamber. The bottom of the heat exchange chamber is connected to the high-temperature bin. A high-temperature discharge valve is arranged at the bottom of the high-temperature bin. The converter flue gas pipe is connected to the air inlet of the solid heat exchanger tower through the high-temperature flue gas dust removal device, and the gas holder is connected to the air outlet of the solid heat exchanger tower through the low-temperature flue gas dust removal device; The dense tube heat exchanger includes a rotary cylinder, a front end seal cover, heat exchange tubes, a rotary joint, and a rear end seal cover. The rotary cylinder is filled with solid particle balls. The heat exchange tubes are densely arranged on the inner wall of the rotary cylinder. The front end seal cover is arranged at the front end of the rotary cylinder. A feeding port is arranged on the front end seal cover, and the feeding port is connected to the high-temperature discharge valve through a chute. The rear end seal cover is arranged at the rear end of the rotary cylinder. A discharge port and a rotary joint are arranged on the rear end seal cover. The discharge port is connected to the feeding end of the bucket elevator through the screening device, and the discharging end of the bucket elevator is connected to the feeding trough of the heat exchange chamber. The water inlet pipeline of the rotary joint is connected to the water inlet of the heat exchange tubes, and the water outlet pipeline of the rotary joint is connected to the water outlet of the heat exchange tubes; The water inlet of the generator is connected to the water outlet pipeline of the rotary joint through the steam pipe, and the water outlet of the generator is connected to the water inlet pipeline of the rotary joint through the water pipe.

[0006] Further, the high-temperature flue gas dust removal device includes a cyclone dust collector. The air inlet of the cyclone dust collector is connected to the converter flue gas pipe, the air outlet of the cyclone dust collector is connected to the air inlet of the heat exchange chamber, and a first ash bin is arranged at the bottom of the cyclone dust collector. A first ash discharge valve is arranged at the bottom of the first ash bin.

[0007] Further, the low-temperature flue gas dust removal device includes a low-temperature flue gas pipe, a bag filter, and a draft fan. One end of the low-temperature flue gas pipe is connected to the air outlet of the heat exchange chamber, and the other end is connected to the gas holder. The bag filter and the draft fan are arranged on the low-temperature flue gas pipe.

[0008] Further, the screening device includes a drum screen. The feeding port of the drum screen is connected to the discharge port of the rear end seal cover. The oversize outlet of the drum screen is connected to the feeding end of the bucket elevator. A second ash bin is arranged below the drum screen. A second ash discharge valve is arranged at the bottom of the second ash bin.

[0009] Further, a support ring is arranged outside the rotary cylinder, and a support roller is arranged below the support ring. The support roller is fixed above the bottom plate.

[0010] Furthermore, the solid particle balls are granular spherical high-temperature heat storage bodies with a particle diameter of 5 - 50 mm, having pores inside, and the maximum porosity not exceeding 50%.

[0011] A method for highly efficient recovery of waste heat from the dry cooling of converter flue gas according to the above-mentioned recovery system includes the following steps: 1) High-temperature flue gas dust removal: The high-temperature converter flue gas is introduced into the high-temperature flue gas dust removal device through the converter flue gas pipe, and preliminary dust removal is carried out through the high-temperature flue gas dust removal device. The high-temperature converter flue gas after preliminary dust removal is transported to the heat exchange chamber of the solid heat exchanger tower; 2) Flue gas heat exchange and temperature reduction: The high-temperature converter flue gas in the heat exchange chamber gradually ascends, and the low-temperature solid particle balls entering from the top of the heat exchange chamber gradually descend under the action of gravity. The high-temperature converter flue gas and the solid particle balls exchange heat during the countercurrent process. The temperature of the high-temperature converter flue gas gradually decreases during the ascending process, and the temperature of the solid particle balls gradually increases during the descending process; 3) Heat exchange of high-temperature solid particle balls: The solid particle balls descend and accumulate in the high-temperature bin after heat exchange in the heat exchange chamber, and then successively pass through the high-temperature discharge valve, chute, and feed port and descend into the rotary cylinder of the tube-in-tube heat exchanger. Low-temperature water is introduced into the heat exchange tubes. The rotary cylinder drives the tube-in-tube to rotate synchronously. The solid particle balls gradually move towards the discharge port under the action of the rotation of the rotary cylinder. The solid particle balls exchange heat with the low-temperature water in the heat exchange tubes during the moving process. The temperature of the solid particle balls gradually decreases, and the low-temperature water in the heat exchange tubes gradually turns into high-temperature and high-pressure steam; 4) Utilization of pressurized steam: The high-temperature and high-pressure steam is transported to the generator through the steam pipe for power generation and turns into low-temperature water. The low-temperature water then returns to the heat exchange tubes of the tube-in-tube heat exchanger through the water pipe for recycling; 5) Recycling of solid particle balls: The solid particle balls are cooled by the tube-in-tube heat exchanger and then enter the screening device through the discharge port for screening. The screened solid particle balls are returned to the heat exchange chamber of the solid heat exchanger tower through the bucket elevator for recycling; 6) Ultra-clean treatment of converter flue gas: The temperature of the high-temperature converter flue gas gradually decreases during the ascending process in the heat exchange chamber, forming low-temperature flue gas. At the same time, the dust concentration decreases. The low-temperature flue gas is discharged from the air outlet of the heat exchange chamber, and is dust-removed again by the low-temperature flue gas dust removal device, and finally transported to the gas holder for storage.

[0012] Furthermore, the initial temperature of the high-temperature converter flue gas introduced into the high-temperature flue gas dust removal device is 1300 - 1600 °C, the dust concentration of the flue gas is 80 - 200 g / Nm³, and the dust concentration of the flue gas after dust removal by the high-temperature flue gas dust removal device is reduced to 3 - 30 g / / Nm³; the temperature of the low-temperature flue gas discharged from the air outlet of the heat exchange chamber is reduced to below 200 °C, and the dust concentration is reduced to 2 g / Nm 3 Within, and the dust concentration of the low-temperature flue gas after being treated by the low-temperature flue gas dust removal device is reduced to 10 mg / Nm 3 Within.

[0013] Furthermore, the temperature of the solid particle balls entering the heat exchange chamber through the feeding chute does not exceed 100°C. The residence time of the solid particle balls in the heat exchange chamber of the solid heat exchange tower is 5 to 60 minutes. The temperature of the solid particle balls accumulated in the high-temperature bin after heat exchange in the heat exchange chamber is 600 to 1200°C. The residence time of the solid particle balls in the rotary cylinder of the tube-in-tube heat exchanger is 10 to 60 minutes.

[0014] Furthermore, the low-temperature water flowing into the heat exchange tubes of the tube-in-tube heat exchanger through the water pipe has a temperature not lower than 60°C, and the high-temperature and high-pressure water steam flowing into the generator through the steam pipe has a pressure not lower than 0.8 MPa.

[0015] Beneficial effects: The present invention innovatively proposes a high-temperature flue gas heat storage vertical furnace waste heat utilization system and method. Firstly, solid particle balls are used as the heat exchange medium to transfer the waste heat of converter gas to the solid particle balls, and then the high-temperature solid particle balls are transported to the rotary tube-in-tube heat exchanger. The high-temperature solid particle balls are used to heat the water in the tube-in-tube heat exchanger and convert it into pressurized steam, so as to send out steam or generate electricity. The present invention changes the process method of high-temperature flue gas cooling. Using solid particle balls as the circulating heat exchange medium, it eliminates the process method of using water-cooled medium in the medium and low temperature sections, and realizes the effective recovery and utilization of waste heat resources in the whole temperature section. Using the method of the present invention, the effective utilization rate of high-temperature flue gas waste heat exceeds 80%. Compared with the traditional process with a recovery utilization rate of only about 40%, the waste heat recovery efficiency is doubled. After being processed by this waste heat recovery process, the investment in the system dust removal process can be effectively reduced.

[0016] The present invention can not only be used for the waste heat recovery of converter flue gas, but also for the waste heat recovery of high-temperature flue gas in other industrial kilns, boilers, incinerators and other fields. It has the advantages of wide application fields, low system investment, reliable equipment operation, high waste heat recovery efficiency, and low cost of ultra-clean flue gas emission. The invention has significant technical and market advantages, and has significant energy-saving and carbon-reducing significance. At present, China attaches great importance to the development of the dual-carbon economy, and the project has huge market promotion space. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a high-efficiency waste heat recovery system for the all-dry cooling of converter flue gas.

[0018] In the figure: 1 - converter flue gas pipe, 2 - cyclone dust collector, 3 - ash bin 1, 4 - ash discharge valve 1, 5 - solid heat exchanger tower, 6 - heat exchange chamber, 7 - air inlet, 8 - air outlet, 9 - high-temperature bin, 10 - high-temperature discharge valve, 11 - chute, 12 - dense tube heat exchanger, 13 - feed inlet, 14 - front end seal cover, 15 - rotary drum, 16 - support ring, 17 - support roller, 18 - heat exchange tube, 19 - bottom plate, 20 - rotary joint, 21 - water pipe, 22 - steam pipe, 23 - generator, 24 - discharge outlet, 25 - drum screen, 26 - ash bin 2, 27 - ash discharge valve 2, 28 - bucket elevator, 29 - conveyor belt, 30 - material conveying chute, 31 - low-temperature flue gas pipe, 32 - bag filter, 33 - induced draft fan, 34 - gas holder, 35 - solid particle ball, 36 - rear end seal cover. Detailed implementation manner

[0019] The present invention will be further explained below with reference to the accompanying drawings.

[0020] As Figure 1 shown, a full dry cooling and waste heat high-efficiency recovery system for converter flue gas of the present invention includes a converter flue gas pipe 1, a high-temperature flue gas dust removal device, a solid heat exchanger tower 5, a dense tube heat exchanger 12, a water pipe 21, a steam pipe 22, a generator 23, a low-temperature flue gas dust removal device, a screening device, a bucket elevator 28, a gas holder 34, and a solid particle ball 35.

[0021] The solid heat exchanger tower 5 includes a heat exchange chamber 6 and a high-temperature bin 9. The heat exchange chamber 6 is filled with solid particle balls 35. A material conveying chute 30 is arranged at the top of the heat exchange chamber 6, an air inlet 7 is arranged below the side surface of the heat exchange chamber 6, an air outlet 8 is arranged above the side surface of the heat exchange chamber 6. The bottom of the heat exchange chamber 6 is connected to the high-temperature bin 9, and a high-temperature discharge valve 10 is arranged at the bottom of the high-temperature bin 9. The converter flue gas pipe 1 is connected to the air inlet 7 of the solid heat exchanger tower 5 through the high-temperature flue gas dust removal device, and the gas holder 34 is connected to the air outlet 8 of the solid heat exchanger tower 5 through the low-temperature flue gas dust removal device. Among them, the high-temperature flue gas dust removal device includes a cyclone dust collector 2. The air inlet of the cyclone dust collector 2 is connected to the converter flue gas pipe 1, the air outlet of the cyclone dust collector 2 is connected to the air inlet 7 of the heat exchange chamber 6, and an ash bin 1 is arranged at the bottom of the cyclone dust collector 2, and an ash discharge valve 1 is arranged at the bottom of the ash bin 1. The low-temperature flue gas dust removal device includes a low-temperature flue gas pipe 31, a bag filter 32, and an induced draft fan 33. One end of the low-temperature flue gas pipe 31 is connected to the air outlet 8 of the heat exchange chamber 6, and the other end is connected to the gas holder 34. The bag filter 32 and the induced draft fan 33 are arranged on the low-temperature flue gas pipe 31.

[0022] The sealed tube heat exchanger 12 includes a rotary drum 15, a front end seal cover 14, heat exchange tubes 18, a rotary joint 20, and a rear end seal cover 36. A support ring 16 is arranged on the outer side of the rotary drum 15, and a support roller 17 is arranged below the support ring 16. The support roller 17 is fixed above the bottom plate 19. Solid particle balls 35 are filled in the rotary drum 15. The heat exchange tubes 18 are densely arranged and installed on the inner wall of the rotary drum 15. The front end seal cover 14 is arranged at the front end of the rotary drum 15, and a feed inlet 13 is arranged on the front end seal cover 14. The feed inlet 13 is connected to a high-temperature discharge valve 10 through a chute 11. The rear end seal cover 36 is arranged at the rear end of the rotary drum 15, and a discharge outlet 24 and a rotary joint 20 are arranged on the rear end seal cover 36. The discharge outlet 24 is connected to the feeding end of a bucket elevator 28 through a screening device. The discharging end of the bucket elevator 28 is connected to the feeding trough 30 of a heat exchange chamber 6 through a conveyor belt 29. The water inlet pipeline of the rotary joint 20 is connected to the water inlet of the heat exchange tubes 18, and the water outlet pipeline of the rotary joint 20 is connected to the water outlet of the heat exchange tubes 18. Among them, the screening device includes a drum screen 25. The feed inlet of the drum screen 25 is connected to the discharge outlet 24 of the rear end seal cover 36. The oversize outlet of the drum screen 25 is connected to the feeding end of the bucket elevator 28. A second ash bin 26 is arranged below the drum screen 25, and a second ash discharge valve 27 is arranged at the bottom of the second ash bin 26.

[0023] The water inlet of the generator 23 is connected to the water outlet pipeline of the rotary joint 20 through a steam pipe 22, and the water outlet of the generator 23 is connected to the water inlet pipeline of the rotary joint 20 through a water pipe 21.

[0024] In this embodiment, the converter flue gas duct 1 is a steel pipe, and the cyclone dust collector 2 is a steel dust collector. Both the converter flue gas duct 1 and the cyclone dust collector 2 are equipped with a refractory insulation layer inside and thermal insulation wool outside. The thickness of the refractory insulation layer is not less than 100 mm, and the thickness of the thermal insulation wool is not less than 50 mm. Ash silo 1 3 and ash silo 2 26 are both steel silos. Ash silo 1 3 is equipped with a refractory insulation layer with a thickness of not less than 80 mm. The ash discharge valve 14, high-temperature discharge valve 10, and ash discharge valve 227 are all electric discharge valves. Both ash discharge valve 14 and high-temperature discharge valve 10 are high-temperature discharge valves, capable of withstanding long-term operating temperatures of not less than 500°C. The heat exchange chamber 6 is the main heat exchange device of the solid-state heat exchange tower 5 and is a steel cylindrical vertical heat exchanger. The high-temperature chamber 9 is an inverted conical steel silo that serves as a buffer for the solid pellets 35. The chute 11 is a steel inverted cone-shaped tubular structure for the downward movement of the solid pellets 35. The heat exchange chamber 6, high-temperature chamber 9, and chute 11 are all equipped with a refractory insulation layer with a thickness of at least 100mm. The front and rear sealing covers 14, 36 are steel structures and are located at the front and rear ends of the rotary drum 15. They use a labyrinth or fish-scale sealing method. Both the front and rear sealing covers 14, 36 are equipped with a refractory insulation layer with a thickness of at least 100mm. Thermal insulation is installed on the outside of the drum 15 with a thickness of at least 50mm. The rotary drum 15 is a horizontal steel cylinder that serves as the heat exchange space for the solid pellets 35. Thermal insulation is installed on the outside of the drum 15 with a thickness of at least 50mm. The support rings 16 and rollers 17 are primarily made of steel and are used to support and secure the drum 15, driving its rotation and promoting movement and heat exchange of the solid pellets 35. The heat exchange tubes 18 are steel pressure pipes that can withstand long-term working pressures of no less than 1.0 MPa. The heat exchange tubes 18 are densely arranged and installed on the inner side of the rotary drum 15. Water flows inside as a heat exchange medium, which is used to exchange heat with the solid granular balls 35 to generate pressurized steam. The rotary joint 20 is a steel pressure-resistant rotary joint that serves as a connection for the flow of water and steam in the water pipe 21, steam pipe 22, and heat exchange tubes 18. The rotary joint 20 can withstand long-term working pressures of no less than 1.0 MPa. The water pipe 21 and steam pipe 22 are both steel pressure pipes that can withstand long-term working pressures of no less than 1.0 MPa. The feed port 13 and the discharge port 24 are both steel chute channels. The feed port 13 serves as a connection for the solid granular balls 35 to travel from the chute 11 to the rotary drum 15. The discharge port 24 serves as a connection for the solid granular balls 35 to travel from the rotary drum 15 to the drum screen 25. A refractory insulation layer of at least 100 mm thick is installed within the feed port 13. The drum screen 25 is a high-temperature, steel-structured screen primarily used for efficient separation of solid pellets 35 from dust. It can withstand long-term operating temperatures of at least 200°C. The mesh width of the drum screen 25 is 5 to 20 mm.The bucket elevator 28 is a steel structure bucket elevator, the conveyor belt 29 is a belt conveyor or a chain bucket conveyor, and the main body of the material conveying trough 30 is a steel structure inverted cone. The low-temperature flue gas pipe 31 is a steel structure pipe. The induced draft fan 33 is a variable frequency induced draft fan, and the gas holder 34 is a steel structure cylindrical cabinet. The solid particle ball 35 is a granular spherical high-temperature heat storage body with a particle diameter of 5 - 50 mm, with pores inside, and the maximum porosity does not exceed 50%. The production material of the solid particle ball 35 is preferably alumina, and the long-term high-temperature operation temperature is not lower than 1300 °C.

[0025] A full dry cooling and waste heat efficient recovery method for converter flue gas of the present invention includes the following steps: 1) High-temperature flue gas dust removal: The high-temperature converter flue gas enters the high-temperature flue gas dust removal device through the converter flue gas pipe 1, and preliminary dust removal is carried out through the high-temperature flue gas dust removal device. The high-temperature converter flue gas first undergoes gravity and cyclone sedimentation in the cyclone dust collector 2 of the high-temperature flue gas dust removal device, and the dust content is reduced to a certain concentration. The converter ash after preliminary sedimentation accumulates in the ash bin 1 3 and is regularly discharged through the ash discharge valve 1 4 for external resource utilization. The high-temperature converter flue gas after preliminary dust removal is transported to the heat exchange chamber 6 of the solid heat exchanger tower 5; 2) Flue gas heat exchange and temperature reduction: A negative pressure is formed in the heat exchange chamber 6 through the induced draft fan 33. The high-temperature converter flue gas in the heat exchange chamber 6 gradually ascends, and the low-temperature solid particle balls 35 entering from the top of the heat exchange chamber 6 gradually descend under the action of gravity. The high-temperature converter flue gas and the solid particle balls 35 exchange heat during the countercurrent process. The temperature of the high-temperature converter flue gas gradually decreases during the ascending process, and the temperature of the solid particle balls 35 gradually increases during the descending process; 3) High-temperature solid particle ball heat exchange: The solid particle balls 35 descend and accumulate in the high-temperature bin 9 after heat exchange in the heat exchange chamber 6, and then successively pass through the high-temperature discharge valve 10, the chute 11, and the feed port 13 to descend into the rotary cylinder 15 of the dense tube heat exchanger 12. Low-temperature water is introduced into the heat exchange tube 18. The rotary cylinder 15 rotates driven by the idler roller 17, and the rotary cylinder 15 drives the dense tube 18 to rotate synchronously. The solid particle balls 35 gradually move towards the discharge port 24 under the action of the rotation of the rotary cylinder 15. The solid particle balls 35 exchange heat with the low-temperature water in the heat exchange tube 18 during the moving process, the temperature of the solid particle balls 35 gradually decreases, and the low-temperature water in the heat exchange tube 18 gradually turns into high-temperature and high-pressure steam; 4) Pressure steam utilization: The high-temperature and high-pressure steam is transported to the generator 23 through the steam pipe 22 for power generation and turns into low-temperature water. The low-temperature water then returns to the heat exchange tube 18 of the dense tube heat exchanger 12 through the water pipe 21 for recycling. The high-temperature and high-pressure steam in the heat exchange tube 18 can also be directly utilized as pressure steam by external discharge; 5) Recycling of solid particle balls: The solid particle balls 35 are cooled by the dense tube heat exchanger 12 and then enter the screening device through the discharge port 24 for screening. The screened solid particle balls 35 are returned to the heat exchange chamber 6 of the solid heat exchange tower 5 through the bucket elevator 28 for recycling. Specifically, under the screening action of the drum screen 25, the solid particle balls 35 enter the bottom of the bucket elevator 28 from above the drum screen 25, and are transported to the top feed chute 30 of the heat exchange chamber 6 of the solid heat exchange tower 5 through the conveyor belt 29 and the feed chute 30 in sequence. The converter ash sedimented with the converter gas enters the second ash bin 26 from below the drum screen 25 and is regularly discharged through the second ash discharge valve 27 for external resource utilization; 6) Ultra-clean treatment of converter gas: During the upward movement of the high-temperature converter gas in the heat exchange chamber 6, the temperature gradually decreases to form low-temperature gas, and at the same time, the dust concentration also decreases to a certain extent. The low-temperature gas is discharged from the air outlet 8 out of the heat exchange chamber 6 and is dusted again by the low-temperature gas dust removal device, and finally transported to the gas holder 34 for storage.

[0026] Among them, the initial temperature of the high-temperature converter gas introduced into the high-temperature gas dust removal device is 1300 - 1600 °C, the dust concentration of the gas is 80 - 200 g / Nm³, and after dust removal by the high-temperature gas dust removal device, the dust concentration of the gas decreases to 3 - 30 g / / Nm³; the temperature of the low-temperature gas discharged from the air outlet 8 out of the heat exchange chamber decreases to below 200 °C, and the dust concentration decreases to 2 g / Nm 3 Within, and after treatment by the low-temperature gas dust removal device, the dust concentration of the low-temperature gas decreases to 10 mg / Nm 3 Within.

[0027] The temperature of the solid particle balls 35 entering the heat exchange chamber 6 through the feed chute 30 does not exceed 100 °C. The residence time of the solid particle balls 35 in the heat exchange chamber 6 of the solid heat exchange tower 5 is 5 - 60 minutes. The temperature of the solid particle balls 35 accumulated in the high-temperature bin 9 after heat exchange in the heat exchange chamber 6 is 600 - 1200 °C, and the residence time of the solid particle balls 35 in the rotary drum 15 of the dense tube heat exchanger 12 is 10 - 60 minutes.

[0028] The low-temperature water introduced into the heat exchange tubes 18 of the dense tube heat exchanger 12 through the water pipe 21 has a temperature not lower than 60 °C, and the high-temperature and high-pressure steam introduced into the generator 23 through the steam pipe ② has a pressure not lower than 0.8 MPa.

[0029] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A fully dry cooling and high-efficiency waste heat recovery system for converter flue gas, characterized in that: It includes a converter gas pipe (1), a high-temperature flue gas dust removal device, a solid heat exchange tower (5), a dense tube heat exchanger (12), a water pipe (21), a steam pipe (22), a generator (23), a low-temperature flue gas dust removal device, a screening device, a bucket elevator (28), a gas holder (34), and solid particle balls (35); The solid heat exchange tower (5) includes a heat exchange chamber (6) and a high-temperature bin (9). The heat exchange chamber (6) is filled with solid particle balls (35). A feeding trough (30) is arranged at the top of the heat exchange chamber (6). An air inlet (7) is arranged below the side of the heat exchange chamber (6). An air outlet (8) is arranged above the side of the heat exchange chamber (6). The bottom of the heat exchange chamber (6) is connected to the high-temperature bin (9). A high-temperature discharge valve (10) is arranged at the bottom of the high-temperature bin (9). The converter gas pipe (1) is connected to the air inlet (7) of the solid heat exchange tower (5) through the high-temperature flue gas dust removal device. The gas holder (34) is connected to the air outlet (8) of the solid heat exchange tower (5) through the low-temperature flue gas dust removal device; The dense tube heat exchanger (12) includes a rotary drum (15), a front end seal cover (14), heat exchange tubes (18), a rotary joint (20), and a rear end seal cover (36). The rotary drum (15) is filled with solid particle balls (35). The heat exchange tubes (18) are densely arranged and installed on the inner wall of the rotary drum (15). The front end seal cover (14) is arranged at the front end of the rotary drum (15). A feeding port (13) is arranged on the front end seal cover (14). The feeding port (13) is connected to the high-temperature discharge valve (10) through a chute (11). The rear end seal cover (36) is arranged at the rear end of the rotary drum (15). A discharge port (24) and a rotary joint (20) are arranged on the rear end seal cover (36). The discharge port (24) is connected to the feeding end of the bucket elevator (28) through the screening device. The discharging end of the bucket elevator (28) is connected to the feeding trough (30) of the heat exchange chamber (6). The water inlet pipeline of the rotary joint (20) is connected to the water inlet of the heat exchange tubes (18). The water outlet pipeline of the rotary joint (20) is connected to the water outlet of the heat exchange tubes (18); The water inlet of the generator (23) is connected to the water outlet pipeline of the rotary joint (20) through the steam pipe (22). The water outlet of the generator (23) is connected to the water inlet pipeline of the rotary joint (20) through the water pipe (21).

2. The full dry cooling and high-efficiency waste heat recovery system for converter flue gas according to claim 1, wherein: The high-temperature flue gas dust removal device includes a cyclone dust collector (2). The air inlet of the cyclone dust collector (2) is connected to the converter gas pipe (1). The air outlet of the cyclone dust collector (2) is connected to the air inlet (7) of the heat exchange chamber (6). A first ash bin (3) is arranged at the bottom of the cyclone dust collector (2). A first ash discharge valve (4) is arranged at the bottom of the first ash bin (3).

3. The full dry cooling and high-efficiency waste heat recovery system for converter flue gas according to claim 1, wherein: The low-temperature flue gas dust removal device includes a low-temperature flue gas pipe (31), a bag filter (32), and a draft fan (33). One end of the low-temperature flue gas pipe (31) is connected to the air outlet (8) of the heat exchange chamber (6), and the other end is connected to the gas holder (34). The bag filter (32) and the draft fan (33) are arranged on the low-temperature flue gas pipe (31).

4. The fully dry cooling and high-efficiency waste heat recovery system for converter flue gas according to claim 1, wherein: The screening device includes a drum screen (25). The feed inlet of the drum screen (25) is connected to the discharge outlet (24) of the rear end sealing cover (36). The over-screen outlet of the drum screen (25) is connected to the feeding end of the bucket elevator (28). A second ash bin (26) is arranged below the drum screen (25), and a second ash discharge valve (27) is arranged at the bottom of the second ash bin (26).

5. The fully dry cooling and high-efficiency waste heat recovery system for converter flue gas according to claim 1, characterized in that: A supporting ring (16) is arranged outside the rotary drum (15), a supporting roller (17) is arranged below the supporting ring (16), and the supporting roller (17) is fixed above the bottom plate (19).

6. The fully dry cooling and high-efficiency waste heat recovery system for converter gas according to claim 1, wherein: The solid particle ball (35) is a granular spherical high-temperature heat storage body with a particle diameter of 5 - 50 mm. Pores are arranged inside, and the maximum porosity does not exceed 50%.

7. A method for highly efficient recovery of waste heat from the dry cooling of converter flue gas in the recovery system according to claim 1, characterized in that, It includes the following steps: 1) High-temperature flue gas dust removal: The high-temperature converter flue gas is introduced into the high-temperature flue gas dust removal device through the converter flue gas pipe (1), and preliminary dust removal is carried out through the high-temperature flue gas dust removal device. The high-temperature converter flue gas after preliminary dust removal is transported into the heat exchange chamber (6) of the solid heat exchange tower (5). 2) Flue gas heat exchange and temperature reduction: The high-temperature converter flue gas in the heat exchange chamber (6) gradually rises. The low-temperature solid particle balls (35) entering from the top of the heat exchange chamber (6) gradually descend under the action of gravity. The high-temperature converter flue gas and the solid particle balls (35) exchange heat during the countercurrent process. The temperature of the high-temperature converter flue gas gradually decreases during the upward movement, and the temperature of the solid particle balls (35) gradually increases during the downward movement. 3) Heat exchange of high-temperature solid particle balls: The solid particle balls (35) descend and accumulate in the high-temperature bin (9) after heat exchange in the heat exchange chamber (6), and then successively pass through the high-temperature discharge valve (10), the chute (11), and the feed inlet (13) to descend into the rotary drum (15) of the tube-in-tube heat exchanger (12). Low-temperature water is introduced into the heat exchange tubes (18). The rotary drum (15) drives the tube-in-tube (18) to rotate synchronously. The solid particle balls (35) gradually move towards the discharge outlet (24) under the rotation of the rotary drum (15). The solid particle balls (35) exchange heat with the low-temperature water in the heat exchange tubes (18) during the movement process. The temperature of the solid particle balls (35) gradually decreases, and the low-temperature water in the heat exchange tubes (18) gradually turns into high-temperature and high-pressure steam. 4) Utilization of pressurized steam: The high-temperature and high-pressure steam is transported to the generator (23) through the steam pipe (22) for power generation and is transformed into low-temperature water. The low-temperature water then returns to the heat exchange tubes (18) of the tube-in-tube heat exchanger (12) through the water pipe (21) for recycling. 5) Recycling of solid particle balls: The solid particle balls (35) are cooled by the tube-in-tube heat exchanger (12) and then enter the screening device through the discharge outlet (24) for screening. The screened solid particle balls (35) are returned to the heat exchange chamber (6) of the solid heat exchange tower (5) through the bucket elevator (28) for recycling. 6) Ultra-clean treatment of converter flue gas: The temperature of the high-temperature converter flue gas gradually decreases during the upward movement in the heat exchange chamber (6), forming low-temperature flue gas. At the same time, the dust concentration decreases. The low-temperature flue gas is discharged from the air outlet (8) of the heat exchange chamber (6) and is dusted again by the low-temperature flue gas dust removal device, and finally transported to the gas holder (34) for storage.

8. A method for efficient recovery of waste heat from the dry cooling of converter flue gas according to claim 7, characterized in that: The initial temperature of the hot converter gas introduced into the high-temperature flue gas dust removal device is 1300 - 1600 °C, and the dust concentration in the gas is 80 - 200 g / Nm³. After dust removal by the high-temperature flue gas dust removal device, the dust concentration in the gas is reduced to 3 - 30 g / Nm³. The temperature of the low-temperature flue gas discharged from the heat exchange chamber through the air outlet (8) is reduced to below 200 °C, and the dust concentration is reduced to 2 g / Nm 3 or less. After being treated by the low-temperature flue gas dust removal device, the dust concentration in the low-temperature flue gas is reduced to 10 mg / Nm 3 or less.

9. A method for highly efficient recovery of waste heat from the cooling of converter flue gas by a fully dry method according to claim 7, characterized in that: The temperature of the solid particle balls (35) entering the heat exchange chamber (6) through the material feeding trough (30) does not exceed 100°C. The residence time of the solid particle balls (35) in the heat exchange chamber (6) of the solid heat exchange tower (5) is 5 to 60 minutes. The temperature of the solid particle balls (35) accumulated in the high-temperature bin (9) after heat exchange in the heat exchange chamber (6) is 600 to 1200°C. The residence time of the solid particle balls (35) in the rotary cylinder (15) of the tube-in-tube heat exchanger (12) is 10 to 60 minutes.

10. A method for highly efficient recovery of waste heat from the dry cooling of converter flue gas according to claim 7, characterized in that: The low-temperature water flowing into the heat exchange tubes (18) of the tube-in-tube heat exchanger (12) through the water pipe (21) has a temperature not lower than 60°C. The high-temperature and high-pressure water steam flowing into the generator (23) through the steam pipe (22) has a pressure not lower than 0.8 MPa.

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