Converter vaporization energy-saving cooling system

Abstract

The utility model provides a converter vaporization energy-saving cooling system which is characterized in that a flue of a converter is respectively connected with a high-pressure circulation module and a low-pressure circulation module, the high-pressure circulation module is circularly communicated with the flue, the low-pressure circulation module is circularly communicated with a to-be-cooled part on the converter, and the to-be-cooled part on the converter is communicated with the high-pressure circulation module. Wherein the high-pressure circulating module adopts a high-pressure circulating pump, and the low-pressure circulating module adopts a low-pressure circulating pump; and the high-pressure circulating pump and the low-pressure circulating pump are in control connection through a frequency converter. According to the converter vaporization energy-saving cooling system, the high-pressure circulation module is arranged on the converter, in the starting process of each smelting period of the converter, the converter is firstly switched to the forced circulation unit to cool the flue, so that it is ensured that the temperature of flue furnace water rises rapidly and is heated uniformly, and after an ideal natural circulation state is formed, the converter is further switched to the natural circulation unit; wherein the low-pressure circulating pump is used for cooling parts to be cooled on the converter.

Description

Technical Field

[0001] This utility model relates to the field of converter gasification energy-saving technology, and in particular to a converter gasification energy-saving cooling system. Background Technology

[0002] Oxygen top-blown converters generate a large amount of high-temperature furnace gas during the smelting process, with temperatures reaching up to 1650°C. The main components are CO, CO2, and dust, which must be cooled and purified before being emitted. The cooling of converter flues is mostly achieved through vaporization cooling. The oxygen converter vaporization cooling device collects the converter gas through the fume hood and absorbs the heat contained in the gas in the water-cooled walls of the flue, thereby reducing the temperature of the gas in the flue. In the existing technology, the vaporization cooling of converters in steel plants is equipped with high-pressure and low-pressure circulation systems. The high-pressure circulation system is divided into natural circulation and forced circulation according to the operating conditions. Natural circulation is usually achieved by using vertical pipes through a straight fume hood. The switching between natural circulation and forced circulation is mainly achieved by a three-way valve. The low-pressure circulation system is mainly used for skirt hoods, oxygen lance hole water jackets, auxiliary lance hole water jackets, and charging hole water jackets, etc., and is operated by low-pressure circulation pumps for low-pressure forced circulation cooling.

[0003] However, the above-mentioned existing technologies have the following shortcomings in application:

[0004] During the converter blowing intervals and process shutdown times, the high and low pressure circulating pumps operate at industrial frequency, resulting in high motor energy consumption and making it difficult to reduce electricity costs in steelmaking production.

[0005] Therefore, in order to solve the above problems, this utility model proposes an energy-saving cooling system for converter vaporization. Utility Model Content

[0006] To address the aforementioned technical problems with existing converter vaporization cooling systems, this invention provides an energy-saving converter vaporization cooling system.

[0007] According to one objective of this utility model, this utility model provides a converter vaporization energy-saving cooling system, wherein a high-pressure circulation module and a low-pressure circulation module are respectively connected to the flue of the converter. The high-pressure circulation module is circulated and connected to the flue, and the low-pressure circulation module is circulated and connected to the components to be cooled on the converter. The high-pressure circulation module adopts a high-pressure circulation pump, and the low-pressure circulation module adopts a low-pressure circulation pump.

[0008] Both the high-pressure circulating pump and the low-pressure circulating pump are connected and controlled by a frequency converter. The frequency converter has at least three operating states: oxygen blowing speed-up state, slag splashing speed-down state, and intermittent speed regulation state. When the smelting stage of the converter is the oxygen blowing stage, the frequency converter is in the oxygen blowing speed-up state, and the frequency converter controls the high-pressure circulating pump to speed up to full load. When the smelting stage of the converter is the slag splashing stage, the frequency converter is in the slag splashing speed-down state, and the frequency converter controls the high-pressure circulating pump to speed down to a first preset flow rate. When the smelting stage of the converter is other than oxygen blowing and slag splashing, the frequency converter is in the intermittent speed regulation state, and the frequency converter controls the connected circulating pump to speed up to a second preset flow rate, the second preset flow rate being no greater than the first preset flow rate.

[0009] Preferably, the high-pressure circulation module includes a switchable natural circulation unit and a forced circulation unit;

[0010] The forced circulation unit includes a first high-pressure steam drum and a high-pressure circulation pump, wherein the first high-pressure steam drum, the high-pressure circulation pump and the flue are sequentially and circulatedly connected; the natural circulation unit includes a second high-pressure steam drum, wherein the second high-pressure steam drum and the flue are circulatedly connected.

[0011] The low-pressure circulation module includes a deaerator water tank and a low-pressure circulation pump, and the deaerator water tank, the low-pressure circulation pump, and the components to be cooled on the converter are sequentially circulated and connected.

[0012] Preferably, unsaturated water is provided in the first high-pressure steam drum. The unsaturated water is arranged to be led out sequentially through the downcomer of the first high-pressure steam drum, pressurized by the high-pressure circulating pump, and sent to the furnace inlet fixed section fume hood, the movable fume hood, the tail corner fume hood, and the flue detection cover of the flue to absorb heat and form a steam-water mixture. The steam-water mixture returns to the first high-pressure steam drum through the riser of the first high-pressure steam drum. The steam-water mixture is separated into saturated steam and saturated water in the first high-pressure steam drum. The saturated steam is led out of the first high-pressure steam drum, and the saturated water is arranged to be mixed with demineralized water added to the first high-pressure steam drum to form unsaturated water.

[0013] Preferably, the natural circulation unit and the forced circulation unit operate at the same pressure.

[0014] Preferably, the second high-pressure steam drum contains unsaturated water, which is configured to be sent to the fixed section flue of the waste heat boiler via the downcomer of the second high-pressure steam drum. The unsaturated water absorbs heat to reach saturation and forms a steam-water mixture. The steam-water mixture returns to the second high-pressure steam drum via the upcomer of the second high-pressure steam drum and is separated into saturated steam and saturated water in the second high-pressure steam drum. The saturated steam is led out to a heat accumulator connected to the second high-pressure steam drum, and the saturated water is configured to be mixed with demineralized water added to the second high-pressure steam drum to form unsaturated water.

[0015] Preferably, the deaerator water tank is filled with saturated water, which is pressurized by the low-pressure circulating pump and sent to the skirt, oxygen lance sleeve, auxiliary lance sleeve and feed chute of the converter to absorb heat, and then returned to the deaerator water tank. The saturated water is configured to use the absorbed heat to deaerate the steam drum feedwater.

[0016] Preferably, the second preset flow rate is less than the first preset flow rate. The slag splashing deceleration state of the frequency converter includes a pre-slag splashing speed-up state and a post-slag splashing speed-down state. When the smelting stage of the converter is the slag splashing start stage, the frequency converter is in the pre-slag splashing speed-up state, and the frequency converter controls the high-pressure circulating pump to increase its speed from the second preset flow rate to the first preset flow rate within a preset time. When the smelting stage of the converter is the slag splashing end stage, the frequency converter is in the post-slag splashing speed-down state, and the frequency converter controls the high-pressure circulating pump to decrease its speed from the first preset flow rate to the second preset flow rate within a preset time.

[0017] Preferably, when the frequency converter controls the acceleration and deceleration of the high-pressure circulating pump and the low-pressure circulating pump, a uniform frequency is given by a dedicated pulse generator and an adder.

[0018] Preferably, the converter is provided with a smelting button panel, which has several buttons for controlling the converter. The buttons correspond to different smelting stages of the converter. The speed regulation of the frequency converter is controlled according to the converter smelting button panel, and the working status of the frequency converter is controlled by one and / or a combination of buttons.

[0019] Preferably, the buttons on the smelting button bar include molten iron addition, converter tilting back to zero, lance lifting, converter tilting angle -60 degrees, and slag splashing. Pressing molten iron addition and converter tilting back to zero together control the high-pressure circulating pump and the low-pressure circulating pump to start increasing the speed from 35Hz to 50Hz, completing the speed-up function. The initial speed-up and speed-down timing length is set to 6 seconds.

[0020] Press the button to delay the lance lifting time by 1 minute and simultaneously control the converter tilt angle to -60 degrees to control the high-pressure circulating pump and the low-pressure circulating pump to start reducing the speed from 50Hz to 35Hz. The initial speed increase / decrease timing length is set to 6 seconds.

[0021] Press the splash control button to start the high-pressure circulating pump and the low-pressure circulating pump to increase their speed from 35Hz to 40Hz. The initial speed increase / decrease timing is set to 5 seconds. Press the splash control button to end the slag discharge and lift the gun. After a 30-second delay, the high and low pressure circulating pumps will start to decrease their speed from 40Hz to 35Hz.

[0022] Compared with the prior art, the beneficial effects of this utility model are:

[0023] This converter vaporization energy-saving cooling system, by setting a high-pressure circulation module on the converter, first switches to the forced circulation unit to cool the flue at the beginning of each smelting cycle to ensure that the flue water temperature rises rapidly and is heated evenly. After forming an ideal natural circulation state, it further switches to the natural circulation unit. The low-pressure circulation pump is used to cool the components on the converter that need to be cooled.

[0024] The converter vaporization cooling module energy-saving module controls the high-pressure circulating pump in the forced circulation unit and the low-pressure circulating pump in the low-pressure circulation module through a frequency converter, so that the high-pressure circulating pump and the low-pressure circulation module can operate at variable frequency during non-blowing periods, effectively saving electricity costs and thus reducing steelmaking production costs.

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the converter vaporization energy-saving cooling system described in this utility model;

[0027] Figure 2 This is a schematic diagram of the control process of the converter vaporization energy-saving cooling system described in this utility model. Detailed Implementation

[0028] The following description is intended to provide a detailed account of the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0029] This utility model provides a technical solution: an energy-saving cooling system for converter vaporization, see [link]. Figure 1The converter's flue 300 is connected to a high-pressure circulation module 100 and a low-pressure circulation module 200, respectively. The high-pressure circulation module 100 includes a switchable natural circulation unit 101 and a forced circulation unit 102.

[0030] The forced circulation unit 102 includes a first high-pressure steam drum 1021 and a high-pressure circulation pump 1022, wherein the first high-pressure steam drum 1021, the high-pressure circulation pump 1022 and the flue 300 are sequentially and circulatedly connected. The natural circulation unit 101 includes a second high-pressure steam drum 1011, wherein the second high-pressure steam drum 1011 and the flue 300 are circulatedly connected.

[0031] The low-pressure circulation module 200 includes a deaerator water tank 201 and a low-pressure circulation pump 202, and the deaerator water tank 201, the low-pressure circulation pump 202 and the components to be cooled on the converter are sequentially and circulated in connection.

[0032] Both the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 are connected and controlled by a frequency converter 400. The frequency converter 400 has at least three operating states: oxygen blowing speed-up state, slag splashing speed-down state, and intermittent speed regulation state. When the smelting stage of the converter is the oxygen blowing stage, the frequency converter 400 is in the oxygen blowing speed-up state, and the frequency converter 400 controls the high-pressure circulating pump 1022 to speed up to full load. When the smelting stage of the converter is the slag splashing stage, the frequency converter 400 is in the slag splashing speed-down state, and the frequency converter 400 controls the high-pressure circulating pump 1022 to speed down to a first preset flow rate. When the smelting stage of the converter is other than oxygen blowing and slag splashing, the frequency converter 400 is in the intermittent speed regulation state, and the frequency converter 400 controls the connected circulating pump to speed up to a second preset flow rate, the second preset flow rate being no greater than the first preset flow rate.

[0033] By setting a high-pressure circulation module 100 on the converter, the converter first switches to the forced circulation unit 102 to cool the flue 300 during the start-up process of each smelting cycle, so as to ensure that the temperature of the flue water rises rapidly and is heated evenly. After forming an ideal natural circulation state, it further switches to the natural circulation unit 101, wherein the low-pressure circulation pump 202 is used to cool the components to be cooled on the converter.

[0034] To avoid the low-pressure circulating pump 202 and the high-pressure circulating pump 1022 operating at industrial frequency during converter blowing intervals and system shutdown times in the converter vaporization cooling process, which results in high motor energy consumption, the converter vaporization cooling module energy-saving module controls the high-pressure circulating pump 1022 in the forced circulation unit 102 and the low-pressure circulating pump 202 in the low-pressure circulation module 200 through a frequency converter 400. This allows the high-pressure circulating pump 1022 and the low-pressure circulation module 200 to operate at variable frequency during non-blowing periods, effectively saving electricity costs and thus reducing steelmaking production costs.

[0035] Specifically, the downcomer of the first high-pressure steam drum 1021 is connected to the input end of the high-pressure circulating pump 1022, and the output end of the high-pressure circulating pump 1022 is connected to the furnace mouth fixed section fume hood, the movable fume hood, the tail corner fume hood and the flue detection cover of the flue 300 respectively. The flue 300 is connected to the riser of the first high-pressure steam drum 1021. More specifically, unsaturated water is provided inside the first high-pressure steam drum 1021. The unsaturated water is arranged to be drawn out sequentially through the downcomer of the first high-pressure steam drum 1021, pressurized by the high-pressure circulating pump 1022, and sent to the furnace mouth fixed section fume hood, the movable fume hood, the tail corner fume hood, and the flue detection cover of the flue 300 to absorb heat and form a steam-water mixture. The steam-water mixture returns to the first high-pressure steam drum 1021 through the riser pipe of the first high-pressure steam drum 1021. The steam-water mixture is separated into saturated steam and saturated water inside the first high-pressure steam drum 1021. The saturated steam is drawn out outside the first high-pressure steam drum 1021. Preferably, the saturated steam is drawn out from the steam drum through the steam main pipe. The saturated water is arranged to be mixed with the demineralized water added to the first high-pressure steam drum 1021 to form unsaturated water. In use, the forced circulation unit 102 operates as follows: Unsaturated water is drawn from the steam drum downcomer, pressurized by the high-pressure circulation pump 1022, and sent to the furnace mouth fixed section fume hood, the movable fume hood, the tail corner fume hood, and the flue detection cover, respectively. After absorbing heat, it returns to the first high-pressure steam drum 1021 through the riser pipe. The steam-water mixture is separated into saturated steam and saturated water in the steam drum. The saturated steam is drawn from the first high-pressure steam drum 1021 and sent out through the steam main pipe. The saturated water mixes with the demineralized water added to the first high-pressure steam drum 1021 to form unsaturated water, and the above cycle is repeated.

[0036] It should be noted that the fixed section of the furnace mouth hood, the movable hood, the tail corner hood, and the flue inspection cover are all part of the converter flue 300. The converter flue 300 is a module used to collect and treat high-temperature flue gas during the converter steelmaking process. It includes multiple parts, such as the movable hood, the fixed section of the furnace mouth flue 300, the intermediate section flue 300, and the final section flue 300. These parts work together to guide the high-temperature flue gas from the converter furnace mouth to subsequent cooling and treatment equipment. Specifically, the main components of the converter flue 300 include: a movable hood, located above the converter, used to collect high-temperature flue gas; the movable hood can move to adapt to different operating positions of the converter; and the fixed section of the furnace mouth flue 300. The fixed-section flue 300 connects the movable fume hood and the intermediate-section flue 300, and is fixed near the converter mouth, providing a stable flue gas passage; the intermediate-section flue 300 connects the fixed-section flue 300 at the furnace mouth and the final-section flue 300, and is used to further guide the flue gas; the final-section flue 300 connects the intermediate-section flue 300 and subsequent cooling equipment, such as a waste heat boiler or dust collector; the tail corner fume hood is used to guide the flue gas into the final-section flue 300, and is usually designed as a corner structure to adapt to different layout requirements; the flue inspection cover is used to inspect and maintain the internal condition of the flue 300 to ensure the normal operation of the flue 300.

[0037] Furthermore, the bend of the flue 300 is equipped with a maintenance manhole cover, and the moving section of the waste heat boiler is provided with a feeding hole, an oxygen lance hole, and an auxiliary lance hole.

[0038] Specifically, the second high-pressure steam drum 1011 is connected to the fixed section flue 300 of the waste heat boiler. The fixed section flue 300 of the waste heat boiler has a relatively good working environment and a low heat load. At the same time, the structure and arrangement of the flue 300 also meet the conditions for natural circulation. To save energy, the fixed section flue 300 adopts a natural circulation vaporization cooling method. The working pressure of the natural circulation unit 101 and the forced circulation unit 102 is the same. More specifically, the second high-pressure steam drum 1011 contains unsaturated water, which is configured to be sent to the fixed section flue 300 via the downcomer of the second high-pressure steam drum 1011. The fixed section flue 300 is the fixed section flue 300 of the waste heat boiler. The unsaturated water absorbs heat to reach saturation and forms a steam-water mixture. The steam-water mixture returns to the second high-pressure steam drum 1011 via the riser, and is separated into saturated steam and saturated water in the second high-pressure steam drum 1011. The saturated steam is led out to the heat accumulator 1012 connected to the second high-pressure steam drum 1011, and the saturated water is mixed with the demineralized water added to the second high-pressure steam drum 1011 to form unsaturated water. In use, the system flow of the natural circulation unit 101 is as follows: Unsaturated water in the second high-pressure steam drum 1011 is sent to the fixed section flue 300 through the downcomer. The unsaturated water absorbs heat in the flue 300 to reach saturation and forms a steam-water mixture. Relying on the density difference between the downcomer and the riser, the mixture returns to the second high-pressure steam drum 1011 through the riser. The steam-water mixture is separated into saturated steam and saturated water in the second high-pressure steam drum 1011. The saturated steam is drawn out from the second high-pressure steam drum 1011 and sent to the heat accumulator 1012. The saturated water mixes with the demineralized water added to the steam drum to form unsaturated water, and the above cycle is repeated.

[0039] Because the boiler water temperature in the fixed section of the flue 300 rises slowly or is unevenly heated during the start-up process of each smelting cycle of the waste heat boiler, it is difficult to form an ideal natural circulation state, which may cause local overheating and burn out the pipes. Therefore, the natural circulation unit 101 and the forced circulation unit 102 are switched to be connected to the flue 300. Preferably, the natural circulation unit 101 and the forced circulation unit 102 are connected to the flue 300 through a three-way switching valve. The switching valve is opened when the smelting cycle starts, so that the natural circulation section has a reliable circulation loop.

[0040] Specifically, the deaerator water tank 201 is filled with saturated water. This saturated water is pressurized by the low-pressure circulating pump 202 and then sent to the cooling components of the converter, such as the skirt, oxygen lance sleeve, auxiliary lance sleeve, and feed chute, to absorb heat before returning to the deaerator water tank 201. The saturated water is configured to use the absorbed heat to deaerate the steam drum feedwater, thereby reducing the amount of auxiliary steam required for deaeration. In operation, the low-pressure circulating module 200 works as follows: saturated water is drawn from the high-pressure deaerator water tank 201, pressurized by the low-pressure circulating pump 202, and then sent to the cooling components in the flue, such as the skirt, oxygen lance sleeve, auxiliary lance sleeve, and feed chute, to absorb heat before returning to the deaerator water tank 201. More specifically, the steam drum feedwater is treated by a deaerator, which operates at a pressure of 0.3–0.5 MPa.

[0041] Furthermore, the low-pressure circulating pump 202 operates in a low-pressure forced circulation cooling mode, and there are two low-pressure circulating pumps 202, namely a main pump and a standby pump.

[0042] Furthermore, the deoxygenated water tank 201 is adapted to supply water to the high-pressure circulation module 100. Specifically, the deoxygenated water tank 201 is connected to the first high-pressure steam drum 1021 and the second high-pressure steam drum 1011, that is, the deoxygenated water tank 201 is used as the water supply tank of the high-pressure circulation module 100.

[0043] See Figure 2 The smelting stages of the converter include: furnace start, 8 minutes of iron charging, 16 minutes of oxygen blowing, 6 minutes of steel tapping, 4 minutes of slag splashing, and furnace intervals other than the above stages. At different times of smelting, the flue gas entering the vaporization flue 300 in the converter has different flue gas volume, flue gas temperature, and flue gas composition, and flues within a large range, resulting in large changes in its heat load.

[0044] Furthermore, the second preset flow rate is less than the first preset flow rate. The slag splashing deceleration state of the frequency converter 400 includes a pre-slag splashing acceleration state and a post-slag splashing deceleration state. When the smelting stage of the converter is the slag splashing start stage, the frequency converter 400 is in the pre-slag splashing acceleration state, and the frequency converter 400 controls the high-pressure circulating pump 1022 to accelerate from the second preset flow rate to the first preset flow rate within a preset time. When the smelting stage of the converter is the slag splashing end stage, the frequency converter 400 is in the post-slag splashing deceleration state, and the frequency converter 400 controls the high-pressure circulating pump 1022 to decelerate from the first preset flow rate to the second preset flow rate within a preset time. In one embodiment, the full-load frequency of the high-pressure circulating pump 1022 is 50Hz, the frequency of the second preset flow rate of the high-pressure circulating pump 1022 is 35Hz, and the frequency of the first preset flow rate of the high-pressure circulating pump 1022 is 40Hz.

[0045] Furthermore, when the frequency converter 400 controls the acceleration and deceleration of the high-pressure circulating pump 1022 and the low-pressure circulating pump 202, a uniform frequency is achieved through a dedicated pulse generator and an adder.

[0046] In one embodiment, the flow rate of the high-pressure circulating pump 1022 is adjusted according to different smelting stages of the converter as follows:

[0047] The converter is in oxygen blowing mode for about 16 minutes, and the frequency converter 400 in the oxygen blowing speed-up mode controls the high-pressure circulating pump 1022 to run at full load.

[0048] The converter is in a slag splashing state for about 4 minutes. During the slag splashing speed reduction state, the frequency converter 400 controls the high-pressure circulating pump 1022 to run at 80% flow rate. The specific flow rate is subject to the actual commissioning data.

[0049] When the converter is in intermittent state, the frequency converter 400 in intermittent speed regulation state controls the high-pressure circulating pump 1022 to run at 70% flow rate, subject to actual debugging data;

[0050] All the above variable frequency data flow control adjusts the minimum flow value according to the heated surface during the commissioning period. This is a very important part of realizing variable frequency control. Specifically, based on the structural dimensions of the steelmaking vaporization module, the temperature of the heated surface of each fume hood component of the module and the required minimum cooling water flow are calculated during the non-blowing period.

[0051] Furthermore, both the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 are equipped with frequency converters 400, and the converter is equipped with a smelting button bar 500. The smelting button bar 500 is equipped with several buttons that control the converter. The buttons correspond to different smelting stages of the converter, and the speed adjustment of the frequency converter 400 is controlled according to the converter smelting button bar 500. Even further, the operating state of the frequency converter 400 is controlled by a combination of one and / or more buttons. In one embodiment, the buttons on the smelting button bar 500 include functions for adding molten iron, returning the converter to zero, raising the lance, adjusting the converter tilt angle to -60 degrees, and splashing slag. Pressing the functions for adding molten iron and returning the converter to zero jointly controls the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 to increase their speed from 35Hz to 50Hz, completing the speed-up function. The initial speed-up / down timing is set to 6 seconds.

[0052] Press the button to delay the lance lifting time by 1 minute and simultaneously control the converter tilt angle to -60 degrees to control the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 to start reducing the speed from 50Hz to 35Hz. The initial speed increase / decrease timing length is set to 6 seconds.

[0053] Press the splash control button to start the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 to increase the speed from 35Hz to 40Hz. The initial speed increase / decrease timing length is 5 seconds. Press the splash control button to end the gun lifting delay for 30 seconds. The high and low pressure circulating pumps 202 will then decrease the speed from 40Hz to 35Hz.

[0054] When the converter smelting is carried out using the double slag method, the process status can be judged based on the total oxygen blowing volume and oxygen blowing time, and the variable frequency speed control system process can be adjusted accordingly.

[0055] Furthermore, the motors of both the high-pressure circulating pump 1022 and the low-pressure circulating pump 202 are directly variable frequency motors.

[0056] In summary, this converter gasification energy-saving cooling system, without modifying the existing high and low pressure circulating pumps 202, transforms the high and low pressure circulating pumps 202 of the converter gasification module from direct start to variable frequency drive, replaces the motor with a variable frequency motor, replaces the corresponding cable with a variable frequency cable, adds a frequency converter 400 and related electrical and instrumentation testing equipment, and modifies the corresponding circulating pump control program and interlocking software.

[0057] The high and low pressure circulating pump 202 operates at variable frequency during non-blowing periods, which can effectively save electricity costs and reduce steelmaking production costs. Taking a steel plant as an example, the annual production capacity of the steel plant is 5.8 million tons. After the energy-saving renovation, the annual electricity cost can be saved by 3.08 million yuan.

[0058] The embodiments described above are only used to illustrate the technical ideas and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. The scope of patent application of this utility model should not be limited by these embodiments. That is, any equivalent changes or modifications made in accordance with the spirit disclosed in this utility model still fall within the patent scope of this utility model.

Claims

1. A converter vaporization energy-saving cooling system, characterized in that, A high-pressure circulation module (100) and a low-pressure circulation module (200) are respectively connected to the flue (300) of the converter. The high-pressure circulation module (100) is circulatedly connected to the flue (300), and the low-pressure circulation module (200) is circulatedly connected to the components to be cooled on the converter. The high-pressure circulation module (100) adopts a high-pressure circulation pump (1022), and the low-pressure circulation module (200) adopts a low-pressure circulation pump (202). Both the high-pressure circulating pump (1022) and the low-pressure circulating pump (202) are connected and controlled by a frequency converter (400). The frequency converter (400) has at least three operating states: oxygen blowing speed-up state, slag splashing speed-down state, and intermittent speed regulation state. When the smelting stage of the converter is the oxygen blowing stage, the frequency converter (400) is in the oxygen blowing speed-up state, and the frequency converter (400) controls the high-pressure circulating pump (1022) to speed up to full load. When the smelting stage of the converter is the slag splashing stage, the frequency converter (400) is in the slag splashing speed-down state, and the frequency converter (400) controls the high-pressure circulating pump (1022) to speed down to a first preset flow rate. When the smelting stage of the converter is a stage other than oxygen blowing and slag splashing, the frequency converter (400) is in the intermittent speed regulation state, and the frequency converter (400) controls the connected circulating pump to speed up to a second preset flow rate, the second preset flow rate being no greater than the first preset flow rate.

2. The converter vaporization energy-saving cooling system according to claim 1, characterized in that, The high-pressure circulation module (100) includes a switchable natural circulation unit (101) and a forced circulation unit (102). The forced circulation unit (102) includes a first high-pressure steam drum (1021) and a high-pressure circulation pump (1022), wherein the first high-pressure steam drum (1021), the high-pressure circulation pump (1022) and the flue (300) are sequentially connected in a circulating manner; the natural circulation unit (101) includes a second high-pressure steam drum (1011), wherein the second high-pressure steam drum (1011) and the flue (300) are sequentially connected in a circulating manner. The low-pressure circulation module (200) includes a deaerator water tank (201) and a low-pressure circulation pump (202), and the deaerator water tank (201), the low-pressure circulation pump (202) and the components to be cooled on the converter are connected in a sequential circulation.

3. The converter vaporization energy-saving cooling system according to claim 2, characterized in that, Unsaturated water is provided inside the first high-pressure steam drum (1021). The unsaturated water is arranged to be led out sequentially through the downcomer of the first high-pressure steam drum (1021), and after being pressurized by the high-pressure circulating pump (1022), it is sent to the furnace mouth fixed section fume hood, the moving fume hood, the tail corner fume hood and the flue detection cover of the flue (300) to absorb heat and form a steam-water mixture. The steam-water mixture returns to the first high-pressure steam drum (1021) through the riser pipe of the first high-pressure steam drum (1021). The steam-water mixture is separated into saturated steam and saturated water in the first high-pressure steam drum (1021). The saturated steam is led out to the outside of the first high-pressure steam drum (1021). The saturated water is arranged to be mixed with the demineralized water added to the first high-pressure steam drum (1021) to form unsaturated water.

4. The converter vaporization energy-saving cooling system according to claim 2, characterized in that, The natural circulation unit (101) and the forced circulation unit (102) operate at the same pressure.

5. The converter vaporization energy-saving cooling system according to claim 2, characterized in that, Unsaturated water is provided in the second high-pressure steam drum (1011). The unsaturated water is configured to be sent to the waste heat boiler fixed section flue (300) through the downcomer of the second high-pressure steam drum (1011). The unsaturated water absorbs heat to reach saturation and forms a steam-water mixture. The steam-water mixture returns to the second high-pressure steam drum (1011) through the riser of the second high-pressure steam drum (1011) and is separated into saturated steam and saturated water in the second high-pressure steam drum (1011). The saturated steam is led out to a heat accumulator (1012) connected to the second high-pressure steam drum (1011). The saturated water is configured to be mixed with demineralized water added to the second high-pressure steam drum (1011) to form unsaturated water.

6. The converter vaporization energy-saving cooling system according to claim 2, characterized in that, The deaerator water tank (201) is filled with saturated water, which is pressurized by the low-pressure circulating pump (202) and sent to the skirt, oxygen lance sleeve, auxiliary lance sleeve and feed chute of the converter to absorb heat, and then returned to the deaerator water tank (201). The saturated water is configured to use the absorbed heat to deaerate the steam drum feedwater.

7. The converter vaporization energy-saving cooling system according to claim 1, characterized in that, The second preset flow rate is less than the first preset flow rate. The slag splashing speed reduction state of the frequency converter (400) includes a speed-up state before slag splashing and a speed-down state after slag splashing. When the smelting stage of the converter is the slag splashing start stage, the frequency converter (400) is in the slag splashing start stage. The frequency converter (400) controls the high-pressure circulating pump (1022) to increase its speed from the second preset flow rate to the first preset flow rate within a preset time. When the smelting stage of the converter is the slag splashing end stage, the frequency converter (400) is in the slag splashing end stage. The frequency converter (400) controls the high-pressure circulating pump (1022) to decrease its speed from the first preset flow rate to the second preset flow rate within a preset time.

8. The converter vaporization energy-saving cooling system according to claim 1, characterized in that, When the frequency converter (400) controls the speed increase and decrease of the high-pressure circulating pump (1022) and the low-pressure circulating pump (202), a uniform frequency is given by a dedicated pulse generator and an adder.

9. The converter vaporization energy-saving cooling system according to claim 1, characterized in that, The converter is provided with a smelting button bar (500), which has several buttons for controlling the converter. The buttons correspond to different smelting stages of the converter. The speed regulation of the frequency converter (400) is controlled according to the converter smelting button bar (500). The working status of the frequency converter (400) is controlled by one and / or a combination of buttons.

10. A converter vaporization energy-saving cooling system according to claim 9, characterized in that, The buttons on the smelting button bar (500) include molten iron, converter tilting back to zero, lance lifting, converter tilting angle -60 degrees and slag splashing. Pressing the molten iron and converter tilting back to zero buttons together control the high-pressure circulating pump (1022) and the low-pressure circulating pump (202) to start increasing the speed from 35Hz to 50Hz, completing the speed-up function. The initial speed-up and speed-down timing length is set to 6 seconds. Press the button to delay the lance lifting time by 1 minute and simultaneously control the high-pressure circulating pump (1022) and the low-pressure circulating pump (202) to start reducing the speed from 50Hz to 35Hz, with the initial speed increase / decrease timing length set at 6 seconds. Press the slag splashing control button to start the high-pressure circulating pump (1022) and the low-pressure circulating pump (202) to increase the speed from 35Hz to 40Hz. The initial speed increase / decrease timing is set to 5 seconds. Press the slag splashing end button and lift the gun for 30 seconds. The high and low pressure circulating pumps (202) will then decrease the speed from 40Hz to 35Hz.

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