Converter vaporization energy-saving cooling system

Abstract

The invention 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, and the low-pressure circulation module is circularly communicated with a to-be-cooled part on the converter; 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] The invention relates to the technical field of converter vaporization energy saving, and in particular to a converter vaporization energy saving cooling system. Background Art

[0002] A large amount of high-temperature furnace gas is generated in the oxygen top-blown converter during the smelting process, and its temperature can reach up to 1650℃. The main components are C0, CO2 and smoke, etc., which must be cooled and purified before being discharged. The cooling of the converter flue mostly adopts vaporization cooling. The oxygen converter vaporization cooling device collects the converter gas through the smoke hood and absorbs the heat contained in the gas in the flue water-cooled wall to reduce the temperature of the gas in the flue. In the prior art, the steel plant converter vaporization cooling is provided with high and low pressure circulation systems. The high pressure circulation system is divided into natural circulation and forced circulation according to the working conditions. The natural circulation is usually a straight smoke hood using a vertical upward pipe to realize natural circulation operation. The natural circulation and forced circulation are mainly switched by a three-way valve. The low pressure circulation system is mainly used for skirt hoods, oxygen gun hole water jackets, auxiliary gun hole water jackets and feeding hole water jackets, etc., and uses a low pressure circulation pump to operate with low pressure forced circulation cooling.

[0003] However, the above-mentioned prior art has the following deficiencies in the application process:

[0004] During the intervals between converter blowing and process shutdown times, the high and low pressure circulation pumps have been operating at industrial frequency, and the corresponding motor energy consumption is relatively large, which makes it difficult to reduce the electricity cost in steelmaking production.

[0005] Therefore, in order to solve the above problems, the present invention proposes a converter vaporization energy-saving cooling system. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned conventional converter vaporization cooling, the present invention provides a converter vaporization energy-saving cooling system.

[0007] According to one object of the present invention, the present invention 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 in circulation communication with the flue, and the low-pressure circulation module is in circulation communication with a component to be cooled on the converter, wherein the high-pressure circulation module adopts a high-pressure circulation pump, and the low-pressure circulation module adopts a low-pressure circulation pump;

[0008] The high-pressure circulation pump and the low-pressure circulation pump are both connected through the control of a frequency converter. The frequency converter has at least three working states, namely, an oxygen blowing speed-up state, a slag splashing speed-down state and an 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 circulation 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 circulation pump to slow 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 is in the intermittent speed regulation state, and the frequency converter controls the connected circulation pump to speed up to a second preset flow rate, and the second preset flow rate is not 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 comprises 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 cyclically connected in sequence, and the natural circulation unit comprises a second high-pressure steam drum, wherein the second high-pressure steam drum and the flue are cyclically connected;

[0011] The low-pressure circulation module comprises a deoxygenated water tank and a low-pressure circulation pump. The deoxygenated water tank, the low-pressure circulation pump and the components to be cooled on the converter are cyclically connected in sequence.

[0012] Preferably, unsaturated water is arranged in the first high-pressure steam drum, and the unsaturated water is arranged to be led out through the downcomer of the first high-pressure steam drum in sequence, and is respectively sent to the fixed section smoke hood of the furnace mouth, the movable smoke hood, the rear corner smoke hood and the flue inspection cover of the flue after being pressurized by the high-pressure circulation pump to absorb heat to form a steam-water mixture, and the steam-water mixture returns to the first high-pressure steam drum through the riser of the first high-pressure steam drum, and the steam-water mixture is separated into saturated steam and saturated water in the first high-pressure steam drum, wherein the saturated steam is led out of the first high-pressure steam drum, and wherein the saturated water is arranged to be mixed with the desalted water added to the first high-pressure steam drum to form unsaturated water.

[0013] Preferably, the working pressures of the natural circulation unit and the forced circulation unit are consistent.

[0014] Preferably, unsaturated water is arranged in the second high-pressure steam drum, and the unsaturated water is arranged to be sent to the fixed section flue of the waste heat boiler through the downcomer of the second high-pressure steam drum, and the unsaturated water absorbs heat to reach a saturated state and forms a steam-water mixture, and the steam-water mixture returns to the second high-pressure steam drum through the riser of the second high-pressure steam drum, and is divided into saturated steam and saturated water in the second high-pressure steam drum, wherein the saturated steam is led out to a heat accumulator connected to the second high-pressure steam drum, and the saturated water is arranged to be mixed with the desalted water added to the second high-pressure steam drum to form unsaturated water.

[0015] Preferably, saturated water is provided in the deoxygenation water tank, and the saturated water is adapted to be pressurized by the low-pressure circulation pump and then sent to the skirt cover, oxygen gun sleeve, auxiliary gun sleeve and feeding chute on the converter to absorb heat, and then returned to the deoxygenation water tank, wherein the saturated water is adapted to use the absorbed heat to deoxygenate the drum feed water.

[0016] Preferably, the second preset flow rate is smaller than the first preset flow rate, and the slag splashing speed reduction state of the frequency converter 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 beginning stage of slag splashing, the frequency converter is in the speed-up state before slag splashing, and the frequency converter controls the high-pressure circulation pump to speed up 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 end stage of slag splashing, the frequency converter is in the speed-down state after slag splashing, and the frequency converter controls the high-pressure circulation pump to speed down from the first preset flow rate to the second preset flow rate within a preset time.

[0017] Preferably, when the frequency converter controls the high-pressure circulation pump and the low-pressure circulation pump to increase or decrease speed, a dedicated pulse generator and an adder are used to achieve uniform frequency setting.

[0018] Preferably, a smelting button bar is provided on the converter, and a plurality of buttons for controlling the connection to the converter are provided on the smelting button bar, 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 bar, and the working state of the frequency converter is controlled by a combination of one and / or more buttons.

[0019] Preferably, the buttons on the smelting button bar include adding molten iron, returning the converter tilting to zero, lifting the gun, the converter tilting angle -60 degrees and slag splashing. Pressing the buttons of adding molten iron and returning the converter tilting to zero jointly controls the high-pressure circulation pump and the low-pressure circulation pump to start increasing the speed from 35Hz to 50Hz, completing the speed increase function, and the initial speed increase and decrease timing length is 6 seconds;

[0020] Press the gun raising delay of 1 minute and the converter tilting angle of -60 degrees to control the high circulation pump and the low pressure circulation pump to start reducing the speed from 50Hz to 35Hz, and the initial speed increase and decrease timing length is 6 seconds;

[0021] Press the slag splash button to control the high circulation pump and the low pressure circulation pump to start speeding up from 35Hz to 40Hz. The initial speed increase and decrease timing length is 5 seconds. Press the slag splash button to end the gun lifting delay of 30s and the high and low pressure circulation pumps start to reduce speed from 40Hz to 35Hz.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The converter vaporization energy-saving cooling system is provided with a high-pressure circulation module on the converter. At the beginning of each smelting cycle, the converter first switches to the forced circulation unit to cool the flue to ensure that the flue water temperature rises quickly and is heated evenly. After forming an ideal natural circulation state, it further switches to the natural circulation unit, in which the low-pressure circulation pump is used to cool the parts to be cooled on the converter.

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

[0025] The present invention is further described below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a converter vaporization energy-saving cooling system according to the present invention;

[0027] Figure 2 The present invention is a schematic diagram of the control flow of a converter vaporization energy-saving cooling system. DETAILED DESCRIPTION

[0028] The following description is used to fully explain the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0029] The present invention provides a technical solution: a converter vaporization energy-saving cooling system, see Figure 1The flue 300 of the converter is respectively connected with a high-pressure circulation module 100 and a low-pressure circulation module 200, wherein 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 drum 1021 and a high-pressure circulation pump 1022, wherein the first high-pressure drum 1021, the high-pressure circulation pump 1022 and the flue 300 are cyclically connected in sequence, and the natural circulation unit 101 includes a second high-pressure drum 1011, wherein the second high-pressure drum 1011 and the flue 300 are cyclically connected;

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

[0032] The high-pressure circulation pump 1022 and the low-pressure circulation pump 202 are both controlled and connected by the frequency converter 400. The frequency converter 400 has at least three working states, namely, an oxygen blowing speed-up state, a slag splashing speed-down state and an 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 circulation 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 circulation 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 circulation pump to speed up to a second preset flow rate, and the second preset flow rate is not greater than the first preset flow rate.

[0033] By setting a high-pressure circulation module 100 on the converter, the converter is first switched to the forced circulation unit 102 to cool the flue 300 at the beginning of each smelting cycle to ensure that the furnace water temperature rises quickly and is heated evenly. After forming an ideal natural circulation state, it is further switched to the natural circulation unit 101, wherein the low-pressure circulation pump 202 is used to cool the parts to be cooled on the converter;

[0034] In order to avoid that during the converter vaporization cooling process, during the converter blowing interval and system shutdown time, the low-pressure circulation pump 202 and the high-pressure circulation pump 1022 have been operating at industrial frequency, resulting in high motor energy consumption, the energy-saving module of the converter vaporization cooling module controls the high-pressure circulation pump 1022 in the forced circulation unit 102 and the low-pressure circulation pump 202 in the low-pressure circulation module 200 through the frequency converter 400, so that the high-pressure circulation pump 1022 and the low-pressure circulation module 200 are operated at variable frequency during the non-blowing time period, effectively saving electricity costs, thereby 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 circulation pump 1022, and the output end of the high-pressure circulation pump 1022 is respectively connected to the furnace mouth fixed section smoke hood, the movable smoke hood, the rear corner smoke hood and the flue inspection cover of the flue 300, and the flue 300 is connected to the ascending pipe of the first high-pressure steam drum 1021. More specifically, unsaturated water is arranged in the first high-pressure steam drum 1021, and the unsaturated water is arranged to be led out through the downcomer of the first high-pressure steam drum 1021 in sequence, and is pressurized by the high-pressure circulation pump 1022 and respectively sent to the fixed section smoke hood of the furnace mouth, the movable smoke hood, the rear corner smoke hood and the flue detection cover of the flue 300 to absorb heat to form a steam-water mixture, and the steam-water mixture returns to the first high-pressure steam drum 1021 through the riser of the first high-pressure steam drum 1021, and the steam-water mixture is separated into saturated steam and saturated water in the first high-pressure steam drum 1021, wherein the saturated steam is led out of the first high-pressure steam drum 1021, and preferably, the saturated steam is led out of the steam drum through the steam main pipe, wherein the saturated water is arranged to be mixed with the desalted water added to the first high-pressure steam drum 1021 to form unsaturated water. When in use, the working process of the forced circulation unit 102 is as follows: unsaturated water is drawn out from the steam drum downcomer, pressurized by the high-pressure circulation pump 1022 and sent to the fixed section smoke hood of the furnace mouth, the mobile smoke hood, the rear corner smoke hood and the flue inspection cover respectively, and then returns to the first high-pressure steam drum 1021 through the riser after absorbing heat. The steam-water mixture is separated into saturated steam and saturated water in the steam drum, and the saturated steam is drawn out from the first high-pressure steam drum 1021 and sent out through the steam main pipe. The saturated water is mixed with the desalted 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 smoke hood at the furnace mouth, the movable smoke hood, the rear corner smoke hood and the smoke duct inspection cover are part of the converter smoke duct 300. The converter smoke duct 300 is a module for collecting and treating high-temperature flue gas during the converter steelmaking process. It includes multiple parts, such as a movable smoke hood, a fixed section smoke duct 300 at the furnace mouth, an intermediate section smoke duct 300, and a final section smoke duct 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 smoke duct 300 include: a movable smoke hood, which is located above the converter and is used to collect high-temperature flue gas. The movable smoke hood can be moved to adapt to different operating positions of the converter; the fixed section smoke duct 300 at the furnace mouth, the fixed section smoke duct 300 at the furnace mouth The fixed-section flue 300 connects the movable smoke hood and the middle-section flue 300, and is fixed near the converter furnace mouth to provide a stable flue gas channel; the middle-section flue 300, the middle-section flue 300 connects the furnace mouth fixed-section flue 300 and the last-section flue 300, and is used to further guide the flue gas; the last-section flue 300, the last-section flue 300 connects the middle-section flue 300 and subsequent cooling equipment, such as a waste heat boiler or a dust collector; the rear corner flue hood, the rear corner flue hood is used to guide the flue gas into the last-section flue 300, and is usually designed as a corner structure to adapt to different layout requirements; the flue inspection cover, the flue inspection cover is used to detect and maintain the internal situation of the flue 300 to ensure the normal operation of the flue 300.

[0037] Furthermore, a manhole cover is provided at the bend of the flue 300, and a feeding hole, an oxygen gun hole, an auxiliary gun hole, etc. are provided on the moving section of the waste heat boiler.

[0038] Specifically, the second high-pressure drum 1011 is connected to the fixed section flue 300 of the waste heat boiler. The working environment of the fixed section flue 300 of the waste heat boiler is relatively good and the heat load is low. At the same time, the structure and arrangement of the flue 300 also have the conditions for adopting natural circulation. In order to save electric energy, the fixed section flue 300 adopts the natural circulation vaporization cooling method. The working pressure of the natural circulation unit 101 and the forced circulation unit 102 are the same. More specifically, unsaturated water is arranged in the second high-pressure steam drum 1011, and the unsaturated water is arranged to be sent to the fixed section flue 300 through the downcomer of the second high-pressure steam drum 1011, and the fixed section flue 300 is the fixed section flue 300 of the waste heat boiler. The unsaturated water absorbs heat to reach a saturated state 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 divided into saturated steam and saturated water in the second high-pressure steam drum 1011, wherein 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 desalted water added to the second high-pressure steam drum 1011 to form unsaturated water. When in use, the system flow of the natural circulation unit 101 is as follows: the 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 a saturated state, forming a steam-water mixture, relying on the density difference between the downcomer and the riser, and returning to the second high-pressure steam drum 1011 through the riser. The steam-water mixture is divided 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 is mixed with the desalted water added to the steam drum to form unsaturated water, and the above cycle is repeated.

[0039] Since the boiler water temperature in the fixed section flue 300 rises slowly or is heated unevenly during the startup of the waste heat boiler at the beginning of each smelting cycle, it is difficult to form an ideal natural circulation state, which may cause local overheating and burn the pipeline. Therefore, the natural circulation unit 101 and the forced circulation unit 102 are switchably 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, and the switching valve is opened when the smelting cycle starts, so that the natural circulation section has a reliable circulation loop.

[0040] Specifically, saturated water is provided in the deoxygenation water tank 201, and the saturated water is configured to be pressurized by the low-pressure circulation pump 202 and sent to the skirt cover, oxygen gun cover, auxiliary gun cover and feeding chute on the converter to wait for the cooling components to absorb heat and return to the deoxygenation water tank 201, wherein the saturated water is configured to use the absorbed heat to deoxygenate the drum feed water to reduce the amount of auxiliary steam for deoxygenation. When in use, the working process of the low-pressure circulation module 200 is as follows: saturated water is drawn out of the high-pressure deoxygenation water tank 201 through a pipeline, and after being pressurized by the low-pressure circulation pump 202, it is sent to the skirt cover, oxygen gun cover, auxiliary gun cover and feeding chute in the smoke pipe and other cooled components, and then returns to the deoxygenation water tank 201 after absorbing heat. More specifically, the drum feed water is processed by a deaerator, and the working pressure of the deaerator is 0.3-0.5MPa.

[0041] Furthermore, the low-pressure circulation pump 202 operates in low-pressure forced circulation cooling, and the number of the low-pressure circulation pumps 202 is two, a normal pump and a standby pump.

[0042] Furthermore, the deoxygenated water tank 201 is suitable for supplying 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 a water supply tank for the high-pressure circulation module 100 .

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

[0044] Further, the second preset flow rate is less than the first preset flow rate, and the slag splashing speed reduction state of the inverter 400 includes a speed increase state before slag splashing and a speed reduction state after slag splashing. When the smelting stage of the converter is the slag splashing start stage, the inverter 400 is in the speed increase state before slag splashing, and the inverter 400 controls the high-pressure circulation pump 1022 to increase the 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 inverter 400 is in the speed reduction state after slag splashing, and the inverter 400 controls the high-pressure circulation pump 1022 to reduce the speed 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 circulation pump 1022 is 50Hz, the frequency of the second preset flow rate of the high-pressure circulation pump 1022 is 35Hz, and the frequency of the first preset flow rate of the high-pressure circulation pump 1022 is 40Hz.

[0045] Furthermore, when the frequency converter 400 controls the high-pressure circulation pump 1022 and the low-pressure circulation pump 202 to increase or decrease speed, a dedicated pulse generator and an adder are used to achieve uniform frequency setting.

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

[0047] The converter is in the oxygen blowing state for about 16 minutes, and the frequency converter 400 in the oxygen blowing speed increasing state controls the high-pressure circulation pump 1022 to operate at full load;

[0048] The converter is in the slag splashing state for about 4 minutes, and the inverter 400 in the slag splashing speed reduction state controls the high-pressure circulation pump 1022 to operate at 80% flow rate, which is subject to actual debugging data;

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

[0050] For all the above frequency conversion data flow control, the minimum flow value is adjusted according to the heating surface during debugging. This is a very important part of realizing frequency conversion control. Specifically, according to the structural dimensions of the steelmaking vaporization module, during the non-blowing time period, the heating surface temperature of each smoke hood component of the module and the required minimum cooling water flow are calculated.

[0051] Furthermore, the high-pressure circulation pump 1022 and the low-pressure circulation pump 202 are both provided with a frequency converter 400, and the converter is provided with a smelting button bar 500, and the smelting button bar 500 is provided with a plurality of buttons for controlling the connection to the converter, and the buttons correspond to different smelting stages of the converter, and the speed regulation of the frequency converter 400 is controlled according to the converter smelting button bar 500. Furthermore, the working 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 adding molten iron, returning the converter tilting to zero, lifting the gun, the converter tilting angle of -60 degrees and slag splashing. Pressing the buttons of adding molten iron and returning the converter tilting to zero jointly controls the high-pressure circulation pump and the low-pressure circulation pump 202 to start speeding up from 35Hz to 50Hz, completing the speed-up function, and the initial speed-up and speed-down timing length is set to 6 seconds;

[0052] Press the gun raising delay of 1 minute and the converter tilting angle of -60 degrees to control the high circulation pump and the low pressure circulation pump 202 to start reducing the speed from 50Hz to 35Hz, and the initial speed increase and decrease timing length is 6 seconds;

[0053] Press the slag splash button to control the high circulation pump and the low pressure circulation pump 202 to start speeding up from 35Hz to 40Hz. The initial speed up and speed down timing length is 5 seconds. Press the slag splash button to end the gun lifting delay of 30s and the high and low pressure circulation pumps 202 start speeding down from 40Hz to 35Hz.

[0054] When the converter smelting adopts the double slag method, the process status can be judged according to the total oxygen blowing amount and oxygen blowing time, and the frequency conversion speed regulation system process can be adjusted.

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

[0056] In summary, the converter vaporization energy-saving cooling system, on the basis of not modifying the existing high and low pressure circulation pumps 202, transforms the high and low pressure circulation pumps 202 of the converter vaporization module from direct start to variable frequency drive, replaces the motor with a variable frequency motor, replaces the corresponding cables with variable frequency cables, adds a frequency converter 400 and related electrical and instrument detection equipment, and modifies the corresponding circulation pump control program and interlocking software.

[0057] The high and low pressure circulation pumps 202 operate at variable frequencies during the non-blowing time period, which can effectively save electricity costs and reduce steelmaking production costs. Taking a certain steel plant as an example, the annual production capacity of the steel plant is 5.8 million tons. After the energy-saving transformation, the electricity bill can be saved by 3.08 million yuan a year.

[0058] The embodiments described above are only used to illustrate the technical ideas and features of the present invention, and their purpose is to enable technicians in this field to understand the content of the present invention and implement it accordingly. The patent scope of the present invention cannot be limited only by this embodiment, that is, any equivalent changes or modifications made according to the spirit disclosed by the present invention still fall within the patent scope of the present invention.

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) and the flue (300) are in circulation communication, and the low-pressure circulation module (200) and the components to be cooled on the converter are in circulation communication, wherein the high-pressure circulation module (100) uses a high-pressure circulation pump (1022), and the low-pressure circulation module (200) uses a low-pressure circulation pump (202); The high-pressure circulation pump (1022) and the low-pressure circulation pump (202) are both controlled and connected via a frequency converter (400). The frequency converter (400) has at least three working states, namely, an oxygen blowing speed-up state, a slag splashing speed-down state, and an 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 circulation 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 circulation 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 circulation pump to speed up to a second preset flow rate, and the second preset flow rate is not greater than the first preset flow rate.

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

3. A converter vaporization energy-saving cooling system according to claim 2, characterized in that: Unsaturated water is arranged in the first high-pressure steam drum (1021). The unsaturated water is arranged to be led out through the downcomer of the first high-pressure steam drum (1021) in sequence, and is respectively sent to the fixed section smoke hood of the furnace mouth, the movable smoke hood, the rear corner smoke hood and the smoke duct detection cover of the flue (300) after being pressurized by the high-pressure circulation pump (1022) to absorb heat to form a steam-water mixture. The steam-water mixture returns to the first high-pressure steam drum (1021) through the riser 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), wherein the saturated steam is led out of the first high-pressure steam drum (1021), and the saturated water is arranged to be mixed with the desalted water added to the first high-pressure steam drum (1021) to form unsaturated water.

4. A converter vaporization energy-saving cooling system according to claim 2, characterized in that: The working pressures of the natural circulation unit (101) and the forced circulation unit (102) are consistent.

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

6. A converter vaporization energy-saving cooling system according to claim 2, characterized in that: Saturated water is arranged in the deoxygenation water tank (201). The saturated water is arranged to be pressurized by the low-pressure circulation pump (202) and then sent to the skirt cover, oxygen gun sleeve, auxiliary gun sleeve and feeding chute on the converter to absorb heat, and then returned to the deoxygenation water tank (201). The saturated water is arranged to use the absorbed heat to deoxygenate the drum feed water.

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

8. A converter vaporization energy-saving cooling system according to claim 1, characterized in that: When the frequency converter (400) controls the high-pressure circulation pump (1022) and the low-pressure circulation pump (202) to increase or decrease speed, a dedicated pulse generator and an adder are used to achieve uniform frequency setting.

9. A converter vaporization energy-saving cooling system according to claim 1, characterized in that: The converter is provided with a smelting button bar (500), and the smelting button bar (500) is provided with a plurality of buttons for controlling the connection with the converter, and 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), and the working state of the frequency converter (400) is controlled by a combination of one and / or more 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 adding molten iron, returning the converter tilting to zero, lifting the gun, the converter tilting angle -60 degrees and slag splashing. Pressing the buttons for adding molten iron and returning the converter tilting to zero jointly controls the high-pressure circulation pump and the low-pressure circulation pump (202) to start increasing the speed from 35 Hz to 50 Hz, completing the speed increase function. The initial speed increase and decrease timing length is set to 6 seconds. Press the gun raising delay of 1 minute and the converter tilting angle of -60 degrees to simultaneously control the high circulation pump and the low pressure circulation pump (202) to start reducing the speed from 50 Hz to 35 Hz, and the initial speed increase and decrease timing length is 6 seconds; Pressing the slag splash button controls the high circulation pump and the low pressure circulation pump (202) to start increasing the speed from 35 Hz to 40 Hz, and the initial speed increase and decrease timing length is 5 seconds. Pressing the slag splash button ends the gun lifting delay of 30 seconds and the high and low pressure circulation pumps (202) start decreasing the speed from 40 Hz to 35 Hz.

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