Sintered ore cooling and sensible heat efficient recovery SCB waste heat boiler replacing cooling machine

Abstract

The utility model relates to the technical field of waste heat boilers, and provides a sinter cooling and sensible heat efficient recovery SCB waste heat boiler replacing a cooling machine, which comprises a vertical furnace body, a steam-water system and a circulating air device, a membrane type water cooling wall, a first evaporator, a superheater, a second evaporator, a coal economizer and a low-temperature heater are sequentially arranged in the vertical furnace body from top to bottom, a feed port is formed in the top of the vertical furnace body, and a discharge port is formed in the bottom of the vertical furnace body; the steam-water system is communicated with the membrane water-cooled wall, the first evaporator, the superheater, the second evaporator, the economizer and the low-temperature heater, and the circulating air device is communicated with the interior of the vertical boiler body. Radiation heat exchange, convection heat exchange and heat conduction composite heat exchange are achieved in the vertical furnace body, the sensible heat recovery efficiency can be greatly improved, meanwhile, the sinter cooling effect can be improved, and it is guaranteed that the rotary drum index is high, and the mine return rate is small.

Description

Technical Field

[0001] This application belongs to the field of waste heat boiler technology, and more specifically, it relates to a sintered ore cooling and sensible heat recovery SCB waste heat boiler that replaces the cooler. Background Technology

[0002] The sintering process in steel production accounts for approximately 10% to 20% of total energy consumption, making it the second largest energy-consuming process after ironmaking. Of the energy consumed in sintering, the sensible heat of the sinter accounts for about 30% of the total energy consumption. The recovery rate of this portion of energy is less than 30%, resulting in a significant waste of energy and indicating substantial potential for recovery and a large market demand. There are currently four methods for cooling sintered ore: First, on-machine cooling, which involves extending the sintering machine and continuing to cool the sintered ore with forced or exhausted air after the sintering process is complete. Second, belt coolers, where the sintered ore is hot-crushed and unloaded onto a belt cooler similar to the sintering machine for forced or exhausted air cooling after the sintering process is complete. Third, annular coolers, where the sintered ore's heat energy is converted into high-temperature waste gas during cooling (temperature between 100-450℃), and a waste heat boiler is used to exchange heat with this high-temperature waste gas, producing low-parameter saturated steam or superheated steam for use in steel plants for production and domestic steam or for power generation. Fourth, vertical cooling furnaces, developed and put into production in recent years, borrow from the dry quenching coke vertical tank cooling process. High-pressure forced or exhausted air is used to cool the sintered ore inside the vertical tank, and the generated hot air is used in a waste heat boiler to produce steam for power generation.

[0003] The above-mentioned sinter cooling methods and waste heat recovery have the following main disadvantages:

[0004] 1. Severe air leakage and high power consumption. The first three cooling methods all involve placing the sinter on a trolley and cooling it with forced or exhausted air. The sealing problem between the trolley and the air box is difficult to solve, and the air leakage rate is generally over 20%, or even as high as 50%, which increases the power consumption for cooling.

[0005] 2. Insufficient heat exchange. In a condenser or annular cooler, the heat exchange between the sinter and the cooling air is cross-flow, resulting in poor heat exchange efficiency; the sinter bed height is low, the heat exchange time between the sinter and the cooling air is short, and the heat exchange is insufficient.

[0006] 3. Low waste heat utilization efficiency. Due to the lack of sealing at both ends of the cooler, a large amount of uncontrolled air is mixed in. Since this uncontrolled air does not pass through the sintering material layer, it not only increases the power and electricity consumption of the fan, but also greatly reduces the temperature of the flue gas after heat exchange. Existing waste heat boilers for sintering machines generally draw air from the higher-temperature sections I and II of the cooler or annular cooler. The large temperature difference between the sinter and the cooling air at the heat exchange end results in low flue gas temperature, significant loss of work capacity, and low waste heat utilization efficiency.

[0007] 4. Large fluctuations in waste heat parameters. The output, temperature, and composition of sintered ore fluctuate greatly during the production process, resulting in significant fluctuations in the parameters of the flue gas after heat exchange, which greatly affects the utilization of waste heat.

[0008] 5. Both belt coolers and annular coolers are large in size, require high investment, consume a lot of energy, require a lot of equipment maintenance, and have a long investment recovery period.

[0009] 6. Sintering waste heat recovery is an important aspect of achieving "energy conservation and emission reduction" targets for steel enterprises. The sensible heat of the waste gas from the ring cooler in the sintering process accounts for approximately 20-28% of the total energy consumption. Therefore, recovering this waste heat is crucial, as it saves energy and provides environmental benefits.

[0010] 7. In recent years, the vertical cooling furnaces developed and put into production have failed to solve the problems of segregation of sintered mineral materials, material flow, and gas-solid heat exchange between sintered ore and cooling gas in several existing experimental projects. Moreover, the power consumption of the fan and the steam production capacity per ton of ore are far from the expectations, and the technical exploration has basically failed. Utility Model Content

[0011] To address the problem of low heat exchange efficiency in the existing technology, the purpose of this application is to provide a sinter cooling and sensible heat recovery SCB waste heat boiler that can replace the cooler, thereby improving the sinter cooling effect, ensuring a high drum index and a low ore return rate, and significantly improving the sensible heat recovery efficiency.

[0012] To achieve the above objectives, the technical solution adopted in this application is as follows: A sinter cooling and sensible heat recovery SCB waste heat boiler that replaces a cooler is provided, comprising: a vertical furnace body, a steam-water system, and a circulating air device. The vertical furnace body is provided with a sinter channel. From top to bottom, the vertical furnace body is provided with a membrane water-cooled wall, a first evaporator, a superheater, a second evaporator, an economizer, and a low-temperature heater. The top of the vertical furnace body has a feed inlet, and the bottom of the vertical furnace body has a discharge outlet. The steam-water system is connected to the membrane water-cooled wall, the first evaporator, the superheater, the second evaporator, the economizer, and the low-temperature heater. The circulating air device is connected to the vertical furnace body.

[0013] In one embodiment, the first evaporator, superheater, second evaporator, economizer, and low-temperature heater all use finned tubes, and the lateral clearance pitch is >100mm.

[0014] In one embodiment, the first evaporator, superheater, second evaporator, economizer and low-temperature heater are arranged vertically at intervals, and the longitudinal clearance pitch is ≥1200mm.

[0015] In one embodiment, the first evaporator, superheater, second evaporator, economizer, and low-temperature heater all adopt a tube-and-box structure.

[0016] In one embodiment, the heating surfaces of the first evaporator and the superheater are arranged in a straight line, the heating surfaces of the economizer and the low-temperature heater are arranged in a straight line, and the heating surface of the second evaporator is staggered with the heating surfaces of the first evaporator and the superheater above it and the heating surfaces of the economizer and the low-temperature heater below it.

[0017] In one embodiment, the circulating air device includes an upper air supply device and a lower air suction device. The upper air supply device is provided at the upper end of the second evaporator, the economizer, and the low-temperature heater, and the lower air suction device is provided at the lower end of the second evaporator, the economizer, and the low-temperature heater.

[0018] In one embodiment, the steam-water system includes a steam drum, a deaerator, and a feedwater pump. The inlet of the low-temperature heater is connected to a first inlet pipe, and the outlet of the low-temperature heater is connected to the deaerator via a first outlet pipe. The inlet of the economizer is connected to the feedwater pump and the deaerator via a second inlet pipe, and the outlet of the economizer is connected to the steam drum via a second outlet pipe. The inlets and outlets of the membrane water-cooled wall, the first evaporator, and the second evaporator are all connected to the steam drum via pipes. The steam inlet of the superheater is connected to the steam drum via a steam pipe, and the superheated steam outlet of the superheater is connected to a heat energy utilization device.

[0019] In one embodiment, at least one discharge port is provided, and the temperature of the sinter discharged from the discharge port is ≤150℃.

[0020] In one embodiment, the pressure of the deaerator is less than or equal to 0.6 MPa.

[0021] The beneficial effects of the sinter cooling and sensible heat recovery SCB waste heat boiler provided in this application, which is an alternative to the cooler, are as follows: by setting up a membrane water-cooled wall, a first evaporator, a superheater, a second evaporator, an economizer, and a low-temperature heater in the vertical furnace body, and cooperating with a steam-water system and a circulating air device, it realizes a composite heat exchange of radiation, convection, and conduction, which can significantly improve the sensible heat recovery efficiency, while improving the sinter cooling effect, ensuring a high drum index and a low ore return rate. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a simplified layout diagram of a sinter cooling and sensible heat recovery SCB waste heat boiler that replaces a cooler, as provided in an embodiment of this application.

[0024] The following are the labeling elements in the figure:

[0025] 1. Steam drum; 2. Deaerator; 3. Feed water pump; 4. Membrane water-cooled wall; 5. First evaporator; 6. Superheater; 7. Second evaporator; 8. Economizer; 9. Low temperature heater; 10. Upper air supply device; 11. Lower air suction device. Detailed Implementation

[0026] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0027] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0028] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] like Figure 1 As shown, this application will now describe a sinter cooling and sensible heat recovery high-efficiency SCB waste heat boiler that replaces a cooler. SCB is an abbreviation for Sinter cooling boiler.

[0031] The sinter cooling and sensible heat recovery SCB waste heat boiler, which replaces the cooler, includes: a vertical furnace body, a steam-water system, and a circulating air device. The vertical furnace body is equipped with a sinter channel. From top to bottom, the vertical furnace body is equipped with a membrane water-cooled wall 4, a first evaporator 5, a superheater 6, a second evaporator 7, an economizer 8, and a low-temperature heater 9. The top of the vertical furnace body is equipped with a feed inlet, and the bottom of the vertical furnace body is equipped with a discharge outlet. The feed inlet is used to connect with the hot sinter screening and distribution machine and the crusher, and the discharge outlet is used to connect with the sinter cooling ore discharge system.

[0032] In this embodiment, the vertical furnace body is provided with heating surfaces of various levels, which are formed by a membrane water-cooled wall 4, a first evaporator 5, a superheater 6, a second evaporator 7, an economizer 8, and a low-temperature heater 9. The steam-water system connects the heating surfaces of each level.

[0033] In this embodiment, the inner wall of the membrane water-cooled wall 4 is welded with pins and covered with wear-resistant castable.

[0034] In this embodiment, multiple first evaporators 5, superheaters 6, second evaporators 7, economizers 8, and low-temperature heaters 9 are arranged laterally at intervals, with a lateral clearance pitch > 100 mm, and the intervals are used to form sintered ore channels; the first evaporators 5, superheaters 6, second evaporators 7, economizers 8, and low-temperature heaters 9 are arranged vertically at intervals, with a longitudinal clearance pitch ≥ 1200 mm. The first evaporators 5, superheaters 6, second evaporators 7, economizers 8, and low-temperature heaters 9 all adopt a tube-box structure, and the heating surfaces are all made of finned tubes.

[0035] In this embodiment, the heating surfaces of the first evaporator 5 and the superheater 6 are arranged in a row, that is, they are on the same plane in the longitudinal direction; the heating surfaces of the economizer 8 and the low-temperature heater 9 are arranged in a row, and the heating surface of the second evaporator 7 is staggered with the heating surfaces of the first evaporator 5 and the superheater 6 above it and the economizer 8 and the low-temperature heater 9 below it.

[0036] In this embodiment, the SCB waste heat boiler is connected to a circulating air system, which includes a circulating air device inside the SCB waste heat boiler. The exterior of the SCB waste heat boiler includes at least a fan, ducts, and a dust removal device. The circulating air device inside the SCB waste heat boiler includes an upper air supply device 10 and a lower air suction device 11, used to realize the flow of heat energy within the vertical furnace body. The upper ends of the second evaporator 7, economizer 8, and low-temperature heater 9 are all equipped with upper air supply devices 10, and the lower ends of the second evaporator 7, economizer 8, and low-temperature heater 9 are all equipped with lower air suction devices 11. In this embodiment, the airflow of the circulating air device can be adjusted by frequency conversion of the fan.

[0037] In this embodiment, the steam-water system includes a steam drum 1, a deaerator 2, and a feedwater pump 3. The inlet of the low-temperature heater 9 is connected to a first inlet pipe, which is connected to an external cold water source. The outlet of the low-temperature heater 9 is connected to the deaerator 2 through a first outlet pipe. The inlet of the economizer 8 is connected to the feedwater pump 3 and the deaerator 2 through a second inlet pipe. The outlet of the economizer 8 is connected to the steam drum 1 through a second outlet pipe. The inlets and outlets of the membrane water-cooled wall 4, the first evaporator 5, and the second evaporator 7 are all connected to the steam drum 1 through pipes. The steam inlet of the superheater 6 is connected to the steam drum 1 through a steam pipe. The superheated steam outlet of the superheater 6 is connected to a heat energy utilization device. The saturated steam from the steam drum 1 enters the superheater 6, is superheated, and then sent to the heat energy utilization device for use. The heat energy utilization device can be a steam turbine generator set, etc. In this embodiment, the steam drum 1 is connected to the membrane water-cooled wall 4, the first evaporator 5, and the second evaporator 7 to form a natural steam-water circulation; the low-temperature heater 9 is the water inlet end, and the superheater 6 is the steam outlet end.

[0038] In this embodiment, at least one discharge port is provided, and the temperature of the sinter discharged from the discharge port is ≤150℃. The number of discharge ports is the same as the number of sinter channels formed by the internal structure of the low-temperature heater 9, and the pressure of the deaerator 2 is less than or equal to 0.6MPa.

[0039] In this embodiment, within the vertical furnace, the sinter flows from top to bottom, while the cooling medium flows from bottom to top, causing the sinter and the cooling medium (water vapor) to flow in opposite directions within the enclosed space of the vertical furnace, thereby extending the cooling time of the sinter. In the high-temperature region (the region of the membrane water-cooled wall 4, the first evaporator 5, and the superheater 6), the sinter undergoes radiative and conductive heat exchange, while in the low-temperature region (the region of the second evaporator 7, the economizer 8, and the low-temperature heater 9), it undergoes a combination of radiative, convective, and conductive heat exchange, significantly improving the heat exchange efficiency.

[0040] In this embodiment, the particle size of the sinter is less than 50 mm, so that it can flow within the lateral clearance pitch; and the sinter can be distributed from fine to coarse when it enters through the feed inlet.

[0041] Working process: First, cold sintered ore is fed into the vertical furnace through the feed inlet, reaching the height of the membrane water-cooled wall 4. Then, the hot sintered ore, after being sized by the process system, falls from fine to coarse into the upper storage section of the vertical furnace (the area where the membrane water-cooled wall 4 is located). The particle size of the sintered ore is less than 50mm. The cold sintered ore is continuously and evenly discharged through the adjustable hydraulic discharge device of the process system. The discharge volume is determined by the height of the upper storage section. The hot sintered ore moves from top to bottom and flows through each stage of heating surfaces. The heat is transferred to the water vapor medium in the heating surfaces through a combination of radiation, conduction, and convection heat exchange, and the temperature of the sintered ore gradually decreases to 150℃. The discharged cold sintered ore is sent to the sintered ore sizing system. The superheated steam generated by this waste heat boiler is exported through a steam header for power generation or thermal energy utilization.

[0042] The SCB waste heat boiler is suitable for sintering hot ore temperatures of 600℃~850℃ and sintering cold ore discharge temperatures ≤150℃. The steam pressure and steam temperature of the SCB waste heat boiler are matched with the sintering ore cooling effect, and the sliding parameters are adjustable.

[0043] Considering manufacturing and transportation capacity limitations, multiple SCB waste heat boilers can be connected in parallel for each sintering machine, depending on its size. Specifically, one SCB waste heat boiler is installed for sintering machines with a capacity of 90 to 180 square meters; two SCB waste heat boilers are installed in parallel for sintering machines with a capacity of 200 to 300 square meters; three SCB waste heat boilers are installed in parallel for sintering machines with a capacity of 360 to 560 square meters; and four SCB waste heat boilers are installed in parallel for sintering machines with a capacity of ≥600 square meters.

[0044] Multiple SCB waste heat boilers connected in parallel can share a single deaerator feedwater system, including deaerator 2 and feedwater pump 3. One deaerator 2 is provided, and N+1 feedwater pumps 3 are provided. N SCB waste heat boilers require N feedwater pumps 3, with one standby feedwater pump 3 shared. The superheated steam generated by the parallel SCB waste heat boilers is fed into the main steam header and sent externally.

[0045] In summary, this embodiment utilizes an SCB waste heat boiler to replace existing sinter ring cooling or belt cooling processes. The cooling process of the sinter occurs within the SCB waste heat boiler, where the sensible heat of the sinter is transferred to the heated surfaces through a combination of radiation, conduction, and convection heat exchange to generate superheated steam for power generation. Compared to existing sinter cooling and waste heat utilization systems, the sinter can be stably cooled to below 150°C, the physical heat recovery rate of steam production capacity increases from approximately 20% to over 75%, and the power consumption per ton of sinter can be reduced by more than 25 kWh.

[0046] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A SCB waste heat boiler for sintered ore cooling and sensible heat efficient recovery that replaces a cooler, characterized in that: include: A vertical furnace body, a steam-water system and a circulating air device, wherein a sintering ore passage is arranged in the vertical furnace body, and a membrane water-cooled wall (4), a first evaporator (5), a superheater (6), a second evaporator (7), an economizer (8) and a low-temperature heater (9) are arranged in sequence from top to bottom in the vertical furnace body, a feed inlet is arranged at the top of the vertical furnace body, and a discharge outlet is arranged at the bottom of the vertical furnace body; the steam-water system is connected to the membrane water-cooled wall (4), the first evaporator (5), the superheater (6), the second evaporator (7), the economizer (8) and the low-temperature heater (9), and the circulating air device is connected to the vertical furnace body.

2. A sintered ore cooling and sensible heat efficient SCB waste heat boiler replacing a cooler as claimed in claim 1, characterized in that: The first evaporator (5), the superheater (6), the second evaporator (7), the economizer (8) and the low-temperature heater (9) all use finned tubes, and the transverse clearance pitch is greater than 100 mm.

3. The SCB waste heat boiler for cooling sintered ore and efficiently recovering sensible heat as a substitute for a cooler as claimed in claim 1, characterized in that: The first evaporator (5), the superheater (6), the second evaporator (7), the economizer (8) and the low-temperature heater (9) are arranged in an upper and lower spacing, and the longitudinal clearance pitch is ≥1200 mm.

4. The SCB waste heat boiler for cooling sintered ore and efficiently recovering sensible heat as a substitute for a cooler as claimed in claim 1, characterized in that: The first evaporator (5), the superheater (6), the second evaporator (7), the economizer (8) and the low-temperature heater (9) all adopt a tube-box structure.

5. A SCB waste heat boiler for cooling sintered ore and efficiently recovering sensible heat as a substitute for a cooler according to any one of claims 1 to 4, characterized in that: The heating surfaces of the first evaporator (5) and the superheater (6) are arranged in series, the heating surfaces of the economizer (8) and the low-temperature heater (9) are arranged in series, and the heating surface of the second evaporator (7) is staggered with the heating surfaces of the first evaporator (5) and the superheater (6) above it and the heating surfaces of the economizer (8) and the low-temperature heater (9) below it.

6. A sintered ore cooling and sensible heat efficient SCB waste heat boiler replacing a cooler as claimed in claim 5, characterized in that: The circulating air device comprises an upper air supply device (10) and a lower air suction device (11); the upper ends of the second evaporator (7), the economizer (8) and the low-temperature heater (9) are all provided with the upper air supply device (10); the lower ends of the second evaporator (7), the economizer (8) and the low-temperature heater (9) are all provided with the lower air suction device (11).

7. A sintered ore cooling and sensible heat efficient SCB waste heat boiler replacing a cooler as claimed in claim 6, characterized in that: The steam-water system comprises a steam drum (1), a deaerator (2) and a feed water pump (3); the water inlet of the low-temperature heater (9) is connected to a first water inlet pipe; the water outlet of the low-temperature heater (9) is connected to the deaerator (2) through a first water outlet pipe; the water inlet of the economizer (8) is connected to the feed water pump (3) and the deaerator (2) through a second water inlet pipe; the water outlet of the economizer (8) is connected to the steam drum (1) through a second water outlet pipe; the water inlet and water outlet of the membrane water-cooled wall (4), the first evaporator (5) and the second evaporator (7) are all connected to the steam drum (1) through pipelines; the steam inlet of the superheater (6) is connected to the steam drum (1) through a steam pipe; and the superheated steam outlet of the superheater (6) is connected to a heat energy utilization device.

8. The SCB waste heat boiler for cooling sintered ore and efficiently recovering sensible heat as a substitute for a cooler as claimed in claim 7, characterized in that: At least one discharge port is provided, and the temperature of the sintered ore discharged from the discharge port is ≤150°C.

9. The SCB waste heat boiler for cooling sintered ore and efficiently recovering sensible heat as a substitute for a cooler as claimed in claim 7, characterized in that: The pressure of the deaerator (2) is less than or equal to 0.6 MPa.

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