CN106967861B - Time-sharing preheating system for combustion air of hot blast stove - Google Patents
Time-sharing preheating system for combustion air of hot blast stove Download PDFInfo
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- CN106967861B CN106967861B CN201710383720.4A CN201710383720A CN106967861B CN 106967861 B CN106967861 B CN 106967861B CN 201710383720 A CN201710383720 A CN 201710383720A CN 106967861 B CN106967861 B CN 106967861B
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 271
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 124
- 239000003546 flue gas Substances 0.000 claims abstract description 124
- 239000002699 waste material Substances 0.000 claims abstract description 124
- 239000007789 gas Substances 0.000 claims description 92
- 239000003034 coal gas Substances 0.000 claims description 24
- 238000004891 communication Methods 0.000 claims description 17
- 230000001276 controlling effect Effects 0.000 claims description 9
- 230000001105 regulatory effect Effects 0.000 claims description 9
- 239000002918 waste heat Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000011449 brick Substances 0.000 description 3
- 239000000571 coke Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000005338 heat storage Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B9/00—Stoves for heating the blast in blast furnaces
- C21B9/14—Preheating the combustion air
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B9/00—Stoves for heating the blast in blast furnaces
- C21B9/10—Other details, e.g. blast mains
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Abstract
The invention relates to a time-sharing preheating system for combustion air of a hot blast stove, which comprises the hot blast stove and a combustion fan, wherein a preheating device in the combustion air stove is arranged at the lower part of an inner cavity of the hot blast stove, and a heat exchange channel for combustion air in the stove and a waste flue gas channel in the stove are arranged in the preheating device in the combustion air stove. The outlet of the combustion-supporting fan can be communicated with the combustion-supporting air inlet through a combustion-supporting air heat exchanger, a combustion-supporting air channel and a first waste flue gas channel are arranged in the combustion-supporting air heat exchanger, the outlet of the combustion-supporting air channel can be communicated with the combustion-supporting air inlet through a first combustion-supporting air passage or a second combustion-supporting air passage, and the combustion-supporting air heat exchange channel in the furnace is connected and communicated with the second combustion-supporting air passage in series. The preheating system can meet the requirement that the hot blast stove accumulates a large amount of heat at the initial stage of burning, can also meet the requirement that the temperature of the vault of the hot blast stove is improved at the middle and later stages of burning, and is simple in structure and low in cost investment.
Description
Technical Field
The invention relates to the technical field of hot blast stoves in metallurgical industry, in particular to a time-sharing preheating system for combustion air of a hot blast stove, which is suitable for an iron-making process.
Background
Along with the large-scale development of blast furnaces and the original higher cost pressure of the steel industry, the blast furnace is particularly important for strengthening smelting and reducing the coke ratio. In addition to the reduction of coke ratio from the aspects of production operation level, raw fuel quality and the like, the improvement of the air supply temperature of the hot blast stove is also an extremely important and effective means.
In order to reach the hot air temperature of over 1250 ℃, a few iron and steel enterprises adopt high-heat-value coal gas (coke oven gas, converter gas and the like) to burn, but domestic iron and steel plants generally lack high-heat-value coal gas, and the realization of high air temperature by using single blast furnace gas to burn is still the preferred scheme of each iron and steel enterprise.
In order to achieve high blast temperatures with single-firing blast furnace gas, the combustion air and gas must be preheated. The common methods are as follows: the method comprises the following steps of preheating combustion air and coal gas at low temperature by adopting a separated heat pipe heat exchanger or a plate heat exchanger, preheating the combustion air at high temperature by adopting an additional preheating furnace or a front-mounted combustion furnace, and the like. The low-temperature double preheating by adopting the separate heat exchanger has the defects that the temperature of preheated combustion-supporting air and preheated coal gas is 180-210 ℃, and the temperature of the vault of the hot blast stove cannot be further increased, so that the temperature of hot blast is increased; the double preheating system adopting the additional preheating furnace or the front combustion furnace belongs to high-temperature preheating (coal gas is preheated to 200 ℃ C., and air is preheated to 420 ℃ C.), can meet the requirement of realizing high air temperature by single-combustion blast furnace gas, but has the defects of complex structure, increased valves, increased occupied area, more consumed coal gas, complex system control, large investment and high operation cost, and cannot be widely applied.
Therefore, the inventor provides a time-sharing preheating system for combustion air of a hot blast stove by virtue of experience and practice of related industries for many years, so as to overcome the defects in the prior art.
Disclosure of Invention
The invention aims to provide a time-sharing preheating system for combustion air of a hot blast stove, which solves the problems of complex structure, high energy consumption, high operation cost and the like of the preheating system in the prior art, can meet the requirement that the hot blast stove accumulates a large amount of heat at the initial stage of burning, can also meet the requirement that the temperature of the vault of the hot blast stove is improved at the middle and later stages of burning, and has simple structure and low cost investment.
The invention aims to realize the purpose, and the time-sharing preheating system for the combustion air of the hot blast stove comprises the hot blast stove and a combustion fan, wherein a gas inlet and a combustion air inlet are arranged at the top of the hot blast stove, a waste flue gas outlet is arranged at the bottom of the hot blast stove and is communicated with the bottom of a chimney, a preheating device in the combustion air stove is arranged at the lower part of an inner cavity of the hot blast stove, a combustion air heat exchange channel in the stove and a waste flue gas channel in the stove are arranged in the preheating device in the combustion air stove, the outlet of the combustion fan can be communicated with the combustion air inlet through a combustion air heat exchanger, a combustion air channel and a first waste flue gas channel are arranged in the combustion air heat exchanger, the outlet of the combustion air channel can be communicated with the combustion air inlet through a first combustion air channel or a second combustion air channel, the combustion air heat exchange channel in the furnace is connected in series and communicated with the second combustion air passage; the top end of the waste flue gas channel in the furnace is communicated with the inner cavity of the hot blast furnace, the bottom end of the waste flue gas channel in the furnace is communicated with the waste flue gas outlet, and the waste flue gas outlet can be communicated with the bottom of the chimney through a first waste flue gas branch and the first waste flue gas channel in sequence.
In a preferred embodiment of the present invention, the gas inlet can be communicated with a blast furnace gas supply pipeline through a gas heat exchanger, a gas channel and a second waste flue gas channel are arranged in the gas heat exchanger, and an outlet of the gas channel is communicated with the gas inlet; the waste flue gas outlet can also be communicated with the bottom of the chimney through a second waste flue gas branch and a second waste flue gas channel in sequence.
In a preferred embodiment of the present invention, the outlet of the combustion-supporting fan can be further communicated with the combustion-supporting air inlet through a combustion-supporting air bypass pipe connected in parallel with the combustion-supporting air heat exchanger, the gas inlet can be further communicated with the blast furnace gas supply pipeline through a gas bypass pipe, and the waste flue gas outlet can be further communicated with the bottom of the chimney through a third waste flue gas branch connected in parallel with the first waste flue gas branch.
In a preferred embodiment of the present invention, an inlet of the combustion air channel is communicated with an outlet of the combustion air blower, a first combustion air channel shut-off valve is connected in series to the first combustion air channel, the second combustion air channel includes a first combustion branch and a second combustion branch, one end of the first combustion branch is communicated with the outlet of the combustion air channel, the other end of the first combustion branch is communicated with one end of the furnace combustion air heat exchange channel, one end of the second combustion branch is communicated with the other end of the furnace combustion air heat exchange channel, and the other end of the second combustion branch is communicated with the combustion air inlet.
In a preferred embodiment of the present invention, a position on the first combustion air passage between the outlet of the combustion air channel and the inlet of the first combustion air passage shut-off valve is provided with one end of the first combustion branch in communication, the other end of the first combustion branch is in communication with one end of the combustion air heat exchange channel in the furnace, and the first combustion branch is connected in series with a first combustion branch shut-off valve; one end of the second combustion-supporting branch is communicated with the other end of the combustion-supporting air heat exchange channel in the furnace, the position, between the stop valve of the first combustion-supporting air channel and the combustion-supporting air inlet, of the first combustion-supporting air channel is communicated with the other end of the second combustion-supporting branch, and the second combustion-supporting branch is connected with the stop valve of the second combustion-supporting branch in series.
In a preferred embodiment of the present invention, a combustion air regulating valve and a combustion air combustion valve are connected in series to the first combustion air passage at a position between the other end of the second combustion air branch and the combustion air inlet.
In a preferred embodiment of the present invention, the combustion air heat exchange channel inside the furnace is formed by connecting a plurality of heat exchange tubes in parallel.
In a preferred embodiment of the present invention, a gas regulating valve, a gas cutoff valve and a gas combustion valve are connected in series between the gas inlet and the outlet of the gas passage and the gas bypass pipe.
In a preferred embodiment of the present invention, a first cut-off valve capable of controlling the communication state of the gas bypass pipe is connected in series to the gas bypass pipe, a second cut-off valve and a third cut-off valve are respectively provided in communication with an inlet and an outlet of the gas channel, and a fourth cut-off valve and a fifth cut-off valve are respectively provided in communication with an inlet and an outlet of the second waste flue gas channel.
In a preferred embodiment of the present invention, a sixth cut-off valve capable of controlling the communication state of the combustion air bypass pipe is connected in series to the combustion air bypass pipe, a seventh cut-off valve and an eighth cut-off valve are respectively connected to the inlet and the outlet of the combustion air channel, and a ninth cut-off valve and a tenth cut-off valve are respectively connected to the inlet and the outlet of the first waste flue gas channel.
In a preferred embodiment of the present invention, a flue valve is disposed at the waste flue gas outlet, and an eleventh cut-off valve capable of controlling the communication state of the third waste flue gas branch is connected in series to the third waste flue gas branch.
From the above, the time-sharing preheating system for combustion air of the hot blast stove has the following beneficial effects:
(1) in the time-sharing preheating system for the combustion air of the hot blast stove, a coal gas heat exchanger and a combustion air heat exchanger are respectively connected with outlets of a blast furnace coal gas supply pipeline and a combustion fan, a waste flue gas outlet of the hot blast stove is respectively communicated with the coal gas heat exchanger and the combustion air heat exchanger, and the waste flue gas exchanges heat with the coal gas and the combustion air respectively to realize primary preheating of the coal gas and the combustion air; the inner cavity of the hot blast stove is provided with a preheating device in a combustion air stove, secondary heat exchange and temperature rise of the combustion air in the inner cavity of the hot blast stove are realized, the theoretical combustion temperature is improved by improving the temperature of the preheated combustion air at the last stage of the stove burning, the vault temperature is further improved, and the heat storage capacity of the checker bricks is increased;
(2) the time-sharing preheating system for the combustion air of the hot blast stove can realize the switching of the combustion air passage through the stop valve arranged on the combustion-supporting branch, and has simple and convenient control and flexible use;
(3) the application of the combustion air time-sharing preheating system of the hot blast stove is not limited by the form of the heat exchanger, the combustion air heat exchanger and the coal gas heat exchanger can adopt the existing heat exchangers in various forms or the combination form thereof, and the combustion air heat exchanger and the coal gas heat exchanger can realize the high-efficiency recovery of waste flue gas waste heat;
(4) the application of the time-sharing preheating system for the combustion air of the hot blast stove is not limited by the form of the hot blast stove, the hot blast stove can be in different forms such as a top combustion type hot blast stove, an external combustion type hot blast stove, an internal combustion type hot blast stove or a ball type hot blast stove, and the time-sharing preheating system for the combustion air of the hot blast stove has strong applicability and is beneficial to popularization and application;
(5) the time-sharing preheating system for the combustion air of the hot blast stove can meet the requirement that the hot blast stove accumulates a large amount of heat at the initial stage of burning and can also meet the requirement that the temperature of the vault of the hot blast stove is increased at the middle and later stages of burning; the time-sharing preheating system for the combustion air of the hot blast stove can fully utilize waste heat of waste flue gas in different stages of burning, and improve the highest vault temperature of the hot blast stove, thereby obtaining high air temperature and reducing energy consumption; the time-sharing preheating system for the combustion air of the hot blast stove has the advantages of simple structure, small occupied area, high flexibility and low cost investment, and is suitable for not only newly built hot blast stoves, but also hot blast stove modification projects.
Drawings
The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:
FIG. 1: is a schematic diagram of the combustion air time-sharing preheating system of the hot blast stove.
In the figure:
100. the time-sharing preheating system of the combustion air of the hot blast stove;
1. a hot blast stove;
101. a gas inlet; 102. a combustion air inlet; 103. a waste flue gas outlet;
2. a combustion fan;
3. a chimney;
4. a preheating device in a combustion air furnace;
51. a gas heat exchanger; 511. a gas channel; 512. a second waste flue gas channel;
52. a gas by-pass pipe;
53. a gas regulating valve; 54. a gas cut-off valve; 55. a gas combustion valve;
61. a combustion air heat exchanger; 611. a combustion air passage; 612. a first waste flue gas channel;
62. a combustion air bypass pipe;
63. a first combustion air passage; 631. a first combustion air passage shut-off valve;
64. a second combustion air passage;
641. a first combustion supporting branch; 6411. a first combustion-supporting branch cut-off valve;
642. a second combustion supporting branch; 6421. a second combustion-supporting branch cut-off valve;
65. a combustion air regulating valve; 66. a combustion air combustion valve;
71. a first waste flue gas branch;
72. a second waste flue gas branch;
73. a third waste flue gas branch;
74. a flue valve;
81. a first shut-off valve; 82. a second shut-off valve; 83. a third shut-off valve; 84. a fourth shut-off valve; 85. a fifth cut-off valve; 86. a sixth cut-off valve; 87. a seventh cut-off valve; 88. an eighth shut-off valve; 89. a ninth cut-off valve; 810. a tenth cut-off valve; 811. an eleventh shut-off valve; 812. a twelfth cut-off valve.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.
As shown in fig. 1, the invention provides a time-sharing preheating system 100 for combustion air of a hot blast stove, which comprises a hot blast stove 1 and a combustion fan 2, wherein in the embodiment, the hot blast stove 1 can adopt a plurality of different forms, such as a top-combustion type, an external-combustion type, an internal-combustion type or a ball type hot blast stove, and the number of the hot blast stoves is a plurality, and the plurality of hot blast stoves are arranged in parallel; the top of the hot blast stove 1 is provided with a gas inlet 101 and a combustion air inlet 102, the bottom of the hot blast stove 1 is provided with a waste flue gas outlet 103, the waste flue gas outlet 103 is communicated with the bottom of the chimney 3, the lower part of the inner cavity of the hot blast stove 1 (the grate pillar area) is provided with a combustion air stove preheating device 4, and the combustion air stove preheating device 4 is internally provided with a stove combustion air heat exchange channel and a stove waste flue gas channel; the outlet of the combustion-supporting fan 2 can be communicated with the combustion-supporting air inlet 102 through a combustion-supporting air heat exchanger 61 or a combustion-supporting air bypass pipe 62 (the combustion-supporting air bypass pipe 62 can be used for process maintenance), the combustion-supporting air bypass pipe 62 and the combustion-supporting air heat exchanger 61 are arranged in parallel, the combustion-supporting air heat exchanger 61 can adopt a heat pipe heat exchanger or other heat exchangers capable of realizing heat exchange of high-temperature waste flue gas, a combustion-supporting air channel 611 and a first waste flue gas channel 612 are arranged in the combustion-supporting air heat exchanger 61, the outlet of the combustion-supporting air channel 611 can be communicated with the combustion-supporting air inlet 102 through a first combustion-supporting air passage 63 or a second combustion-supporting air passage 64, and the combustion-supporting air heat exchange channels in the furnace are communicated with the second combustion-supporting air passage 64 in series; the gas inlet 101 can be communicated with a blast furnace gas supply pipeline (in the prior art, not shown in the figure) through a gas heat exchanger 51 or a gas bypass pipe 52, the gas bypass pipe 52 is arranged in parallel with the gas heat exchanger 51, the gas heat exchanger 51 can adopt a heat pipe heat exchanger or other heat exchangers capable of realizing heat exchange of high-temperature waste flue gas, a gas channel 511 and a second waste flue gas channel 512 are arranged in the gas heat exchanger 51, an outlet of the gas channel 511 is communicated with the gas inlet 101, and in the embodiment, a gas regulating valve 53, a gas stop valve 54 and a gas combustion valve 55 are sequentially connected in series between the outlets of the gas channel 511 and the gas bypass pipe 52 and the gas inlet 101; the top end of the waste flue gas channel in the furnace is communicated with the inner cavity of the hot blast furnace 1, the bottom end of the waste flue gas channel in the furnace is communicated with the waste flue gas outlet 103, the waste flue gas outlet 103 can be communicated with the bottom of the chimney 3 through a first waste flue gas branch 71, a second waste flue gas branch 72 or a third waste flue gas branch 73 (the third waste flue gas branch 73 can be used for process maintenance), the first waste flue gas branch 71, the second waste flue gas branch 72 and the third waste flue gas branch 73 are arranged in parallel, the first waste flue gas branch 71 is communicated with the first waste flue gas channel 612 in series, the second waste flue gas branch 72 is communicated with the second waste flue gas channel 512 in series, and the outlets of the first waste flue gas channel 612 and the second waste flue gas channel 512 are communicated with the bottom of the chimney 3. In this embodiment, a flue valve 74 is disposed at the waste flue gas outlet 103, and an eleventh cut-off valve 811 capable of controlling the communication state of the third waste flue gas branch 73 is connected in series with the third waste flue gas branch 73. Waste flue gas generated by burning of the hot blast stove 1 firstly passes through a waste flue gas channel in the combustion air furnace in the preheating device 4 from a waste flue gas outlet 103 to pass through the hot blast stove 1, and then flows to a chimney 3 through a first waste flue gas branch 71, a first waste flue gas channel 612, a second waste flue gas branch 72, a second waste flue gas channel 512 or a third waste flue gas branch 73 to be discharged out of the system.
In the time-sharing preheating system for the combustion air of the hot blast stove, the outlets of a blast furnace gas supply pipeline and a combustion fan are respectively connected with a gas heat exchanger and a combustion air heat exchanger, a waste flue gas outlet of the hot blast stove is respectively communicated with the gas heat exchanger and the combustion air heat exchanger, and the waste flue gas exchanges heat with the gas and the combustion air respectively to realize primary preheating of the gas and the combustion air; the inner cavity of the hot blast stove is provided with a preheating device in a combustion air stove, secondary heat exchange and temperature rise of the combustion air in the inner cavity of the hot blast stove are realized, the theoretical combustion temperature is improved by improving the temperature of the preheated combustion air at the last stage of the stove burning, the vault crown temperature is further improved, and the heat storage capacity of checker bricks (in the prior art) is increased; the application of the combustion air time-sharing preheating system of the hot blast stove is not limited by the form of the heat exchanger, the combustion air heat exchanger and the coal gas heat exchanger can adopt the existing heat exchangers in various forms or the combination form thereof, and the combustion air heat exchanger and the coal gas heat exchanger can realize the high-efficiency recovery of waste flue gas waste heat; the application of the hot blast stove combustion air time-sharing preheating system is not limited by the form of the hot blast stove, and the hot blast stove combustion air time-sharing preheating system has strong applicability and is beneficial to popularization and application; the time-sharing preheating system for the combustion air of the hot blast stove can meet the requirement that the hot blast stove accumulates a large amount of heat at the initial stage of burning and can also meet the requirement that the temperature of the vault of the hot blast stove is increased at the middle and later stages of burning; the time-sharing preheating system for the combustion air of the hot blast stove can fully utilize waste heat of waste flue gas at different stages of burning, and improve the highest vault temperature of the hot blast stove, thereby obtaining high air temperature and reducing energy consumption; the time-sharing preheating system for the combustion air of the hot blast stove has the advantages of simple structure, small occupied area, high flexibility and low cost investment, and is suitable for not only newly built hot blast stoves, but also hot blast stove modification projects.
Further, as shown in fig. 1, an inlet of the combustion air channel 611 is communicated with an outlet of the combustion air blower 2, a first combustion air channel shut-off valve 631 is connected in series to the first combustion air channel 63, the second combustion air channel 64 includes a first combustion branch 641 and a second combustion branch 642, one end of the first combustion branch 641 is communicated with the outlet of the combustion air channel 611, the other end of the first combustion branch 641 is communicated with one end of the furnace combustion air heat exchange channel, one end of the second combustion branch 642 is communicated with the other end of the furnace combustion air heat exchange channel, and the other end of the second combustion branch 642 is communicated with the combustion air inlet 102. In this embodiment, in order to better utilize the waste heat of the waste flue gas, the other end of the first combustion-supporting branch 641 is communicated with the bottom end of the combustion-supporting air heat exchange channel in the furnace, and one end of the second combustion-supporting branch 642 is communicated with the top end of the combustion-supporting air heat exchange channel in the furnace. In the present embodiment, a combustion air adjusting valve 65 and a combustion air combustion valve 66 are connected in series to the first combustion air passage 63 at a position between the other end of the second combustion air branch 642 and the combustion air inlet 102 in this order.
Further, as shown in fig. 1, a position of the first combustion air channel 63 between the outlet of the combustion air channel 611 and the inlet of the first combustion air channel shut-off valve 631 is provided with one end of the aforementioned first combustion branch 641 in a communicating manner, the other end of the first combustion branch 641 is communicated with one end of the furnace combustion air heat exchange channel, and the first combustion branch 641 is connected in series with a first combustion branch shut-off valve 6411; one end of the second combustion-supporting branch 642 is communicated with the other end of the combustion-supporting air heat exchange channel in the furnace, the position between the first combustion-supporting air passage cut-off valve 631 and the combustion-supporting air inlet 102 on the first combustion-supporting air passage 63 is communicated with the other end of the second combustion-supporting branch 642, and the second combustion-supporting branch 642 is connected in series with a second combustion-supporting branch cut-off valve 6421. At the initial stage of the combustion of the hot blast stove, when the preheating device 4 in the combustion-supporting air stove is not needed to be started, the first combustion-supporting branch cut-off valve 6411 and the second combustion-supporting branch cut-off valve 6421 are closed, the first combustion-supporting air passage cut-off valve 631 is opened, and combustion-supporting air is conveyed into the hot blast stove 1 through the first combustion-supporting air passage 63; in the middle and later period of the combustion of the hot blast stove, when the preheating device 4 in the combustion-supporting air stove needs to be started, the first combustion-supporting air access cut-off valve 631 is closed, the first combustion-supporting branch cut-off valve 6411 and the second combustion-supporting branch cut-off valve 6421 are opened, and combustion-supporting air is conveyed into the hot blast stove 1 through the first combustion-supporting branch 641, the combustion-supporting air heat exchange channel in the stove, the second combustion-supporting branch 642, the combustion-supporting air regulating valve 65 and the combustion-supporting air combustion valve 66. In practical operation, the time for putting the preheating device 4 in the combustion-supporting air furnace in the hot blast stove 1 into use can be flexibly controlled according to the temperature of the waste flue gas, and the time can be selected when the temperature of the waste flue gas is greater than a set value, and the set value can be 220 ℃, 250 ℃, 300 ℃ or other temperatures.
Further, as shown in fig. 1, a first cut-off valve 81 capable of controlling the communication state of the gas bypass pipe 52 is connected in series to the gas bypass pipe 52, a second cut-off valve 82 and a third cut-off valve 83 are respectively provided in communication with the inlet and the outlet of the gas channel 511, and a fourth cut-off valve 84 and a fifth cut-off valve 85 are respectively provided in communication with the inlet and the outlet of the second waste flue gas channel 512.
Further, as shown in fig. 1, a sixth cut-off valve 86 capable of controlling the communication state of the combustion air bypass pipe 62 is connected in series to the combustion air bypass pipe 62, a seventh cut-off valve 87 and an eighth cut-off valve 88 are respectively provided in communication with the inlet and the outlet of the combustion air channel 611, and a ninth cut-off valve 89 and a tenth cut-off valve 810 are respectively provided in communication with the inlet and the outlet of the first waste flue gas channel 612.
As shown in fig. 1, the number of the combustion fan 2 is plural, the plural combustion fans 2 are arranged in parallel, a twelfth cut-off valve 812 is respectively arranged at the outlets of the plural combustion fans, and the outlet of each twelfth cut-off valve 812 can be communicated with the inlet of the combustion air channel 611 or the inlet of the combustion air bypass pipe 62. In a particular embodiment of the invention, the number of combustion air blowers 2 is two.
In a specific embodiment of the present invention, the hot-blast stove 1 is a top-combustion hot-blast stove, at the initial stage of burning the hot-blast stove 1, the temperature of the waste flue gas is low, and the preheating device 4 in the combustion-supporting air stove is not required to be started, at this time, the first cut-off valve 81, the sixth cut-off valve 86, the first combustion-supporting branch cut-off valve 6411, the second combustion-supporting branch cut-off valve 6421 and the eleventh cut-off valve 811 are closed, the second cut-off valve 82, the third cut-off valve 83, the fourth cut-off valve 84, the fifth cut-off valve 85, the seventh cut-off valve 87, the eighth cut-off valve 88, the ninth cut-off valve 89, the tenth cut-off valve 810, the flue valve 74 and the first combustion-supporting air passage cut-off valve 631 are opened, at this time, the gas enters the hot-blast stove 1 through the gas passage 511, the gas adjusting valve 53, the gas cut-off valve 54 and the gas combustion valve 55 through the gas inlet 101 for combustion, and the combustion-supporting air enters the hot-blast stove 1 through the combustion-supporting air passage 611, the first combustion-supporting air passage 63, the combustion-supporting air passage 65 and the combustion-supporting air combustion valve 66 through the combustion-supporting air inlet 102 for combustion-supporting air passage 102 Burning; the waste flue gas generated in the hot blast stove 1 is discharged to a chimney through a second waste flue gas channel 512 and a first waste flue gas channel 612, and the waste flue gas exchanges heat with the coal gas and the combustion-supporting air respectively in the coal gas heat exchanger 51 and the combustion-supporting air heat exchanger 61, so that the primary preheating of the coal gas and the combustion-supporting air is realized;
in the middle and later period of the combustion of the hot blast stove, after the temperature of the waste flue gas rises to be greater than a set value (for example 290 ℃), the preheating device 4 in the combustion-supporting air stove is started, the first combustion-supporting branch cut-off valve 6411 and the second combustion-supporting branch cut-off valve 6421 are opened, the first combustion-supporting air access cut-off valve 631 is closed, the combustion-supporting air is conveyed to the hot blast stove 1 through the combustion-supporting air channel 611, the first combustion-supporting branch 641, the stove combustion-supporting air heat exchange channel, the second combustion-supporting branch 642, the combustion-supporting air regulating valve 65 and the combustion-supporting air combustion valve 66, and the waste flue gas exchanges heat with the combustion-supporting air in the preheating device 4 in the combustion-supporting air stove, so that the secondary preheating of the combustion-supporting air is realized.
In a specific embodiment of the invention, when the hot-blast stove 1 is fired, the gas heat exchanger 51 and the combustion air heat exchanger 61 are started, and the preheating device 4 in the combustion air stove is not started, the average temperature of the waste flue gas is about 325 ℃, and the gas heat exchanger 51 and the combustion air heat exchanger 61 can be adopted to preheat the gas and the combustion air to about 200 ℃; in the middle and later period of the combustion of the hot blast stove, the preheating device 4 in the combustion-supporting air furnace is started, part of heat of the waste flue gas is used for carrying out secondary preheating on the combustion-supporting air in the combustion-supporting air heat exchange channel in the furnace, the average temperature of the waste flue gas flowing out from the waste flue gas outlet is reduced to about 295 ℃, the coal gas heat exchanger 51 and the combustion-supporting air heat exchanger 61 are adopted to preheat the coal gas and the combustion-supporting air to about 175 ℃, and the average temperature of the combustion-supporting air led to the combustion-supporting air heat exchange channel in the furnace is 175 ℃. The temperature of the waste flue gas generated in the hot blast stove is continuously increased and can reach 430 ℃ at most, and when the waste flue gas is used for secondarily preheating combustion-supporting air, the ratio of the quantity of the waste flue gas passing through the waste flue gas channel in the stove to the quantity of the combustion-supporting air in the combustion-supporting air heat exchange channel in the stove is twice of the ratio of the quantity of the waste flue gas passing through the first waste flue gas channel 612 to the quantity of the combustion-supporting air in the combustion-supporting air channel 611 (half of the quantity of the waste flue gas passing through the waste flue gas channel in the stove preheats coal gas through the second waste flue gas channel 512), the quantity of the waste flue gas is sufficient, and the waste flue gas can preheat the combustion-supporting air at 175 ℃ to above 320 ℃. When the preheating temperature of the combustion air in the later stage of the burning furnace reaches 320 ℃, the temperature of the vault of the hot blast stove can be at least increased by 40 ℃, and the air supply temperature can be increased by more than 30 ℃.
From the above, the time-sharing preheating system for combustion air of the hot blast stove has the following beneficial effects:
(1) in the time-sharing preheating system for the combustion air of the hot blast stove, the outlets of a blast furnace gas supply pipeline and a combustion fan are respectively connected with a gas heat exchanger and a combustion air heat exchanger, a waste flue gas outlet of the hot blast stove is respectively communicated with the gas heat exchanger and the combustion air heat exchanger, and the waste flue gas exchanges heat with the gas and the combustion air respectively to realize primary preheating of the gas and the combustion air; the inner cavity of the hot blast stove is provided with a preheating device in a combustion air stove, secondary heat exchange and temperature rise of the combustion air in the inner cavity of the hot blast stove are realized, the theoretical combustion temperature is improved by improving the temperature of the preheated combustion air at the last stage of the stove burning, the vault temperature is further improved, and the heat storage capacity of the checker bricks is increased;
(2) the time-sharing preheating system for the combustion air of the hot blast stove can realize the switching of the combustion air passage through the stop valve arranged on the combustion-supporting branch, and has simple and convenient control and flexible use;
(3) the application of the combustion air time-sharing preheating system of the hot blast stove is not limited by the form of the heat exchanger, the combustion air heat exchanger and the coal gas heat exchanger can adopt the existing heat exchangers in various forms or the combination form thereof, and the combustion air heat exchanger and the coal gas heat exchanger can realize the high-efficiency recovery of waste flue gas waste heat;
(4) the application of the time-sharing preheating system for the combustion air of the hot blast stove is not limited by the form of the hot blast stove, the hot blast stove can be in different forms such as a top combustion type hot blast stove, an external combustion type hot blast stove, an internal combustion type hot blast stove or a ball type hot blast stove, and the time-sharing preheating system for the combustion air of the hot blast stove has strong applicability and is beneficial to popularization and application;
(5) the time-sharing preheating system for the combustion air of the hot blast stove can meet the requirement that the hot blast stove accumulates a large amount of heat at the initial stage of burning and can also meet the requirement that the temperature of the vault of the hot blast stove is increased at the middle and later stages of burning; the time-sharing preheating system for the combustion air of the hot blast stove can fully utilize waste heat of waste flue gas at different stages of burning, and improve the highest vault temperature of the hot blast stove, thereby obtaining high air temperature and reducing energy consumption; the time-sharing preheating system for the combustion air of the hot blast stove has the advantages of simple structure, small occupied area, high flexibility and low cost investment, and is suitable for not only newly built hot blast stoves, but also hot blast stove modification projects.
The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the protection scope of the invention.
Claims (10)
1. A time-sharing preheating system for combustion air of a hot blast stove comprises the hot blast stove and a combustion fan, wherein a coal gas inlet and a combustion air inlet are arranged at the top of the hot blast stove, the bottom of the hot blast stove is provided with a waste flue gas outlet which is communicated with the bottom of the chimney, it is characterized in that the lower part of the inner cavity of the hot blast stove is provided with a combustion-supporting air furnace preheating device, a furnace combustion-supporting air heat exchange channel and a furnace waste flue gas channel are arranged in the combustion-supporting air furnace preheating device, the outlet of the combustion-supporting fan can be communicated with the combustion-supporting air inlet through a combustion-supporting air heat exchanger, a combustion air channel and a first waste flue gas channel are arranged in the combustion air heat exchanger, an outlet of the combustion air channel can be communicated with the combustion air inlet through a first combustion air channel or a second combustion air channel, and the combustion air heat exchange channel in the furnace is connected in series and communicated with the second combustion air channel; the top end of the waste flue gas channel in the furnace is communicated with the inner cavity of the hot blast furnace, the bottom end of the waste flue gas channel in the furnace is communicated with the waste flue gas outlet, and the waste flue gas outlet can be communicated with the bottom of the chimney through a first waste flue gas branch and the first waste flue gas channel in sequence.
2. The time-sharing preheating system for combustion air of a hot-blast stove according to claim 1, wherein the gas inlet can be communicated with a supply pipeline of blast furnace gas through a gas heat exchanger, a gas channel and a second waste flue gas channel are arranged in the gas heat exchanger, and an outlet of the gas channel is communicated with the gas inlet; the waste flue gas outlet can also be communicated with the bottom of the chimney through a second waste flue gas branch and a second waste flue gas channel in sequence.
3. A combustion air time-sharing preheating system of a hot blast stove according to claim 2, wherein the outlet of the combustion air blower is further communicated with the combustion air inlet through a combustion air bypass pipe arranged in parallel with the combustion air heat exchanger, the gas inlet is further communicated with the blast furnace gas supply pipeline through a gas bypass pipe, and the waste flue gas outlet is further communicated with the bottom of the chimney through a third waste flue gas branch arranged in parallel with the first waste flue gas branch.
4. A hot blast stove combustion air time-sharing preheating system according to claim 1, wherein an inlet of the combustion air passage is communicated with an outlet of the combustion air blower, a first combustion air passage shut-off valve is connected in series to the first combustion air passage, the second combustion air passage includes a first combustion air branch and a second combustion air branch, one end of the first combustion air branch is communicated with the outlet of the combustion air passage, the other end of the first combustion air branch is communicated with one end of the furnace combustion air heat exchange passage, one end of the second combustion air branch is communicated with the other end of the furnace combustion air heat exchange passage, and the other end of the second combustion air branch is communicated with the combustion air inlet.
5. A hot-blast stove combustion air time-sharing preheating system according to claim 4, characterized in that a position on the first combustion air passage between the outlet of the combustion air passage and the inlet of the first combustion air passage shut-off valve is communicated with one end of the first combustion branch, the other end of the first combustion branch is communicated with one end of the furnace combustion air heat exchange passage, and the first combustion branch is connected with the first combustion branch shut-off valve in series; one end of the second combustion-supporting branch is communicated with the other end of the combustion-supporting air heat exchange channel in the furnace, the position, between the stop valve of the first combustion-supporting air channel and the combustion-supporting air inlet, of the first combustion-supporting air channel is communicated with the other end of the second combustion-supporting branch, and the second combustion-supporting branch is connected with the stop valve of the second combustion-supporting branch in series.
6. A time-sharing preheating system for combustion air of a hot blast stove according to claim 5, characterized in that a combustion air regulating valve and a combustion air combustion valve are connected in series in the first combustion air passage at a position between the other end of the second combustion branch and the combustion air inlet.
7. A time-sharing preheating system for combustion air of a hot blast stove according to claim 3, wherein a gas regulating valve, a gas shut-off valve and a gas combustion valve are connected in series between the outlets of the gas passage and the gas by-pass pipe and the gas inlet in sequence.
8. The time-sharing preheating system for combustion air of a hot blast stove according to claim 3, wherein a first cut-off valve capable of controlling the communication state of the gas bypass pipe is connected in series to the gas bypass pipe, a second cut-off valve and a third cut-off valve are respectively communicated and arranged at the inlet and the outlet of the gas channel, and a fourth cut-off valve and a fifth cut-off valve are respectively communicated and arranged at the inlet and the outlet of the second waste flue gas channel.
9. A combustion air time-sharing preheating system of a hot blast stove according to claim 3, wherein a sixth cut-off valve capable of controlling the communication state of the combustion air bypass pipe is connected in series to the combustion air bypass pipe, a seventh cut-off valve and an eighth cut-off valve are respectively communicated and arranged at the inlet and the outlet of the combustion air channel, and a ninth cut-off valve and a tenth cut-off valve are respectively communicated and arranged at the inlet and the outlet of the first waste flue gas channel.
10. The time-sharing preheating system for combustion air of a hot blast stove according to claim 3, wherein a flue valve is arranged at the waste flue gas outlet, and an eleventh cut-off valve capable of controlling the communication state of the third waste flue gas branch is connected in series to the third waste flue gas branch.
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| CN107227382A (en) * | 2017-07-31 | 2017-10-03 | 中冶京诚工程技术有限公司 | Hot blast stove system of blast furnace |
| CN114410870B (en) * | 2022-01-24 | 2023-03-14 | 中天钢铁集团(南通)有限公司 | Smoke control and exhaust system and method for coke oven gas burning of hot blast stove |
| CN115751318A (en) * | 2022-11-28 | 2023-03-07 | 中钢设备有限公司 | Gas heating device and method |
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| GB378259A (en) * | 1930-10-17 | 1932-08-11 | Naamlooze Vennootschap Nieuwe | Improvements in hot blast stove systems |
| CN100398668C (en) * | 2005-06-30 | 2008-07-02 | 宝山钢铁股份有限公司 | Technological process and apparatus for heating high concentration CO and other reducing gas |
| CN201785423U (en) * | 2010-07-29 | 2011-04-06 | 江苏中天能源设备有限公司 | Gas preheating combined heat-pipe heat exchanger |
| CN201785425U (en) * | 2010-07-29 | 2011-04-06 | 江苏中天能源设备有限公司 | Air preheating combined heat pipe heat exchanger of blast furnace |
| CN102618681A (en) * | 2012-04-19 | 2012-08-01 | 河南省豫兴热风炉工程技术有限公司 | Grate-free double-preheating top combustion type hot blast stove |
| CN202532702U (en) * | 2012-05-02 | 2012-11-14 | 刘力铭 | Top combustion hot-blast stove capable of achieving double preheating through mix of high-temperature smoke and low-temperature smoke |
| CN102952913B (en) * | 2012-11-12 | 2015-07-15 | 鞍钢集团工程技术有限公司 | Dual-preheating method and device for preheating blast furnace gas by using heat-storage-type preheating furnace |
| CN206736291U (en) * | 2017-05-26 | 2017-12-12 | 中冶京诚工程技术有限公司 | Time-sharing preheating system for combustion air of hot blast stove |
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