JPS6124448B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to blast furnace gas cleaning equipment that collects dust in gas discharged from a blast furnace. Blast furnace gas has a high calorific value and is an important source of thermal energy, but since it contains a large amount of dust, there is a risk of damaging various equipment if used without removing the dust. Equipment that appropriately combines dry dust collectors, wet dust collectors, electrostatic precipitators, etc. is widely used as blast furnace gas purification equipment. FIGS. 1 and 2 are equipment configuration diagrams showing examples of conventional blast furnace gas purification equipment. In Figure 1,
The dust-containing gas generated in the blast furnace 1 flows into the dust catcher 3 via the dust catcher inlet rough gas pipe 2. In dust catcher 3, dust is separated by gravity settling, and at the inlet of dust catcher 3.
The dust concentration, which was ^about 20g/Nm3, decreased to 5 at the outlet.
g/ ^Nm3 . The gas leaving the dust catcher 3 is the dust catcher outlet rough gas pipe 4.
The water flows through the bench lily scrubber 5 and is cleaned in the bench lily scrubber 5. The concentration of gas and dust at the vent lily scrubber 5 outlet is 100m
g/ ^Nm3 . The gas cleaned in the bench lily scrubber 5 is transferred to the vent lily scrubber outlet pipe 6 or the bench lily scrubber mist separator 5.
Part of the gas is used for pressure equalization at the top of the furnace, and most of the gas is used as fuel. A part of the gas used for equalizing the pressure at the top of the furnace is sent through the top pressure equalizing pipe 7 to a raw material charging device provided at the top of the blast furnace, and is used for equalizing the pressure at the time of charging the raw material. Most of the gas used as fuel is semi-clean gas pipe 6
The dust is then sent to a bench lily scrubber 8 where it is cleaned and reduced to a predetermined dust concentration or lower. and,
The gas is sent to a hot stove, gas holder, etc. through the clean gas pipe 9 and used as fuel. The equipment shown in Fig. 2 is the equipment shown in Fig. 1 in which the second-stage bench turret scrubber 8 is replaced with an electrostatic precipitator 10, and the other equipment is exactly the same and its operation is the same. be. By the way, the above conventional blast furnace gas cleaning equipment has the following drawbacks. That is, at least two or more dust collectors must be installed following the dust catcher 3, which increases equipment and operating costs and requires a large installation space. Furthermore, since dust collection in the dust catcher 3 is insufficient, the members of the subsequent dust collection device are severely worn. Furthermore, the pressure loss throughout the gas cleaning equipment is quite high.
The energy contained in blast furnace gas cannot be used efficiently. Therefore, this invention solves the above-mentioned problems in conventional blast furnace gas cleaning equipment, and aims to provide an economical blast furnace gas cleaning equipment with less wear on equipment members and low pressure loss. . Hereinafter, the present invention will be explained in detail based on preferred embodiments with reference to the drawings. FIG. 3 is an equipment configuration diagram showing an example of the present invention. In the figure, a duplex dust catcher 11 is connected to the top side of a blast furnace 1 via a dust catcher inlet coarse gas pipe 2. The dual dust catcher 11 has a closed container 12 with a gravity settling chamber 13 and a centrifugal or electrostatic dust collection chamber 14. The outlet side of the duplex dust catcher 11 is connected to a bench turret scrubber 17 via a dust catcher outlet rough gas pipe 15, and the dust catcher outlet rough gas pipe 15 is connected to the blast furnace via a furnace top pressure equalizing pipe 16 in the middle. It is connected to the top of the furnace. In addition, the outlet side of the bench uri scrubber 17 is connected to a hot stove, gas holder, etc. with a clean gas pipe 1, as in conventional equipment.
8. FIG. 4 shows another example of this invention, and the third
In the apparatus shown in the figure, the bench unit scrubber 17 is simply replaced with a known electrostatic precipitator 19, moving packed bed dust collector 19 or electrostatic coagulation type moving packed dust collector 19. The duplex dust catcher 11 shown in FIGS. 3 and 4 will now be described in detail. In the dual dust catcher shown in FIG. 5, the centrifugal separation chamber is constituted by a cyclone. The duplex dust catcher includes a closed container 21 having a generally cylindrical shape, and the container 21 is installed so that the axis of the container is vertical. The container 21 consists of a dust hopper 22, a gravity sedimentation separation chamber 23, and a clean gas chamber 24 in order from the bottom.
3 and the clean gas chamber 24 are separated by a partition plate 25. Further, the container 21 is provided with a vertical gas introduction pipe 27 which passes through the top 26 of the container and whose lower end opens into the gravity sedimentation separation chamber 23, and an outlet duct 28 which leads from the clean gas chamber 24 to the outside of the container 21. Two cyclones 29 are installed in the gravity sedimentation separation chamber 23. That is, the top of the cyclone 29 is fixed to the partition plate 25, and the introduction pipe 30 of the cyclone 29 is connected to the gravity sedimentation separation chamber 23.
The outlet pipe 31 also opens into the clean gas chamber 24 . A discharge duct 35 is connected to the dust hopper 32 of each cyclone 29 to the outside of the container 21.
are connected. Note that cutting devices 36 and 37 are attached to the bottom of the dust hopper 22 of the container 21 and the outlet of the discharged dust 35, respectively. Next, the operation of the dual dust catcher configured as described above will be explained. The blast furnace gas from the top of the furnace passes through the gas introduction pipe 27,
It flows into the gravity sedimentation separation chamber 23. The inflowing gas spreads throughout the chamber in the gravity sedimentation separation chamber 23, reduces the flow velocity, and is reversed upward. At this time, most of the dust with large particle diameters and some of the dust with small particle diameters are separated from the gas flow due to the action of inertia and gravity that tend to move downward, and accumulate in the dust hopper 22. The gas that has reached the top of the gravity settling chamber 23 then flows into the cyclone 29 here. At this time, the gas enters the cyclone barrel 33 in a tangential direction, becomes a swirling flow, and descends spirally inside the barrel 33. During this time, the dust in the gas collides with the trunk wall 34 under the influence of centrifugal force and is deposited. The deposited dust then descends along the shell wall 34 due to gravity and the downward gas flow, and settles to the lower part of the dust hopper 32. The gas thus purified after passing through the gravity sedimentation separation chamber 23 and the cyclone 29 flows into the next dust collector 17 or 19 via the clean gas chamber 24 and the outlet duct 28 . On the other hand, the dust P that has settled in the dust hopper 22 of the container 21 and the dust hopper 32 of the cyclone 29 is taken out of the multiple dust catcher by the cutting devices 36 and 37. FIG. 6 shows another example of a dual dust catcher. Similar to the one shown in FIG.
7, etc., a closed container 41, a gas introduction pipe 48,
It is equipped with an outlet duct 49, a cutting device 50, and the like. Inside the centrifugal separation chamber 44, a spiral guide plate 45 is attached around the inlet duct 48 to form a spiral flow path 46 extending from the bottom to the top. In the dual dust catcher configured as described above, the gas that has passed through the gravity sedimentation separation chamber 43 flows into the centrifugal separation chamber 44 and reaches the clean gas chamber 47 via the spiral flow path 46. At this time, the gas flows through the flow path 46
spiral movement along. The dust remaining without being separated in the gravity sedimentation separation chamber 43 is directed outward by centrifugal action and collides with the body wall of the container 41 or the guide plate 45 to be separated from the gas, and is sent to the dust hopper along the flow path 46. Falling at 42. FIGS. 7 and 8 show still another example of a dual dust catcher. Similar to the one shown in FIG. 6, this double dust catcher also includes a closed container 51, a gas inlet pipe 59, an outlet duct 60, and a gas inlet pipe 59, an outlet duct 60, and a closed container 51, which is composed of a dust hopper 52, a gravity sedimentation separation chamber 53, a centrifugal separation chamber 54, a clean gas chamber 55, etc. It is equipped with a device 69 and the like. An annular inclined partition plate 56 is installed between the gravity sedimentation separation chamber 53 and the centrifugation chamber 54. This partition plate 56
An oblique cylindrical peripheral wall 61 is attached to the container body wall 58 so as to form an annular dust storage portion 62 therebetween. A substantially cylindrical turning chamber 63 whose top portion is closed with a blind plate 64 is attached to the upper end of this peripheral wall 61. The swirling chamber 63 opens in the radial direction from an inner chamber 65 communicating with the gravity sedimentation chamber 53 to the centrifugation chamber 54 . This communication path is a swirling flow path 66, and a large number of guide vanes 67 having a dogleg-shaped cross section are arranged along the circumferential direction. Therefore, the gas is guided in the circumferential direction from the swirling flow path 66 and flows out into the centrifugal separation chamber 54 in a swirling manner. Further, the lower end of the swirl flow path 66 is closed by a bottom plate 68 that slopes outward. In the dual dust catcher configured as described above, the gas that has passed through the gravity settling separation chamber 53 is
It reaches the inner chamber 65 through the surrounding wall 61, and the swirling flow path 66
flows into. Here, the gas becomes a swirling flow and flows out into the centrifugal separation chamber 54. At this time, the dust collides with the guide vane 67 and settles, falls onto the bottom plate 68, and further slides along the bottom plate 68 into the dust storage section 62. Further, in the centrifugal separation chamber 54, the dust in the gas is subjected to centrifugal force due to the swirling flow of the gas, collides with the container body wall 58, and is deposited.
The dust falls along the dust trap 62 and accumulates in the dust storage section 62. Figures 9 to 12 show an example of a dual dust catcher equipped with an electrostatic dust collection chamber instead of a centrifugal separation chamber.
-A sectional view, FIG. 11 is a sectional view taken along line BB in FIG. 9, and FIG. 12 is a sectional view taken along line AA in FIG. 9. Similar to the one shown in FIG.
4, etc., and a gas introduction pipe 7.
5, an outlet duct 76, a cutting device 77, etc. In addition, the centrifugation chamber 4 shown in FIG.
4 serves as an electrostatic dust collection chamber 78 here. The electrostatic dust collection chamber 78 is shown in Fig. 10 (or Fig. 12).
) and FIG. 11, the inlet duct 7
A plate-shaped dust collection electrode 79 is provided so as to form a large number of partitioned spaces radially and concentrically around the center 5, for example, and a discharge wire 80 is arranged in each space. The discharge wire 80 is held at its upper end by a concentric disk-shaped discharge wire support frame 81.
This discharge wire support frame 81 is suspended by a support insulator 83 provided at the top of the container 71 via a suspension rod 82. Note that a tubular dust collection electrode 79 shown in FIG. 12 may be used instead of the dust collection electrode 79 shown in FIG. 10. Furthermore, although a hammering device for brushing off dust adhering to the discharge wires and dust collecting electrodes is not shown, it can of course be installed at an appropriate position. Gravity sedimentation separation chamber 7 of the above duplex dust catcher
The operations up to 3 are similar to the three dual dust catchers described above. The gas flow reversed and ascended in the gravity sedimentation separation chamber 73 enters the electrostatic dust collection chamber 78, where particles charged by corona discharge between the discharge wire 80 and the dust collection electrode 79 or 79' adhere to the dust collection electrode 79 or 79'. do. Therefore, in this electrostatic dust collection chamber 78, most of the large particle size dust and small particle size dust that remained unseparated in the gravity sedimentation separation chamber 73 are almost completely separated from the gas. Become. The dust adhering to the dust collecting electrode 79 or 79' and the discharge wire 80 is knocked off by its own weight or by a hammering device or the like, and accumulates in the dust hopper 72.
It is appropriately discharged by a cutting device 77. The dual dust catcher is not limited to the above embodiment. For example, in the case of the embodiment shown in Fig. 5, there were two cyclones, but there may be one or three or more cyclones; in short, a gravity sedimentation separation chamber, a centrifugation chamber, or It is only necessary to have an electrostatic dust collection chamber. The overall function of the blast furnace gas cleaning equipment of the present invention is similar to that of conventional equipment, but it has the following effects. Compared to conventional equipment, the blast furnace gas cleaning equipment of the present invention does not require a single bench lily scrubber, so the installation space, equipment cost, operating cost, maintenance cost, etc. of the equipment can be reduced. In addition, since the duplex dust catcher collects dust by gravity sedimentation, centrifugation, or electrostatic collection, the dust concentration at the inlet of the duplex dust catcher was ^{approximately} 20 g/Nm3. However, at the outlet, the concentration is about 100 to 300 mg/ ^Nm3 . Therefore, it is significantly smaller than the conventional value of 5 g/Nm ³ , and wear caused by dust on the members of the ventilator scrubber following the dual dust catcher is greatly reduced. Furthermore, the blast furnace gas cleaning equipment of the present invention has less pressure loss. Tables 1 and 2 show the furnace top pressure
An example is shown in which the pressure loss in the operating state in the case of 2.0 Kg/cm ² is compared between the conventional equipment and the equipment of the present invention.

【table】

[Table] As is clear from both tables, the pressure loss of the entire blast furnace gas cleaning equipment of the present invention is significantly smaller than that of the conventional equipment. Therefore, when a furnace top pressure recovery turbine is installed, for example, when the equipment of the present invention is used, a large amount of recovered energy can be recovered and energy saving can be achieved. Regarding the pressure equalizing gas at the top of the furnace, conventional equipment uses the gas at the outlet of the primary venturi scrubber 5, but in the equipment of this invention, the gas from the outlet of the dual dust catcher 1 is used.
One outlet of gas can be used. As is clear from Tables 1 and 2, the difference between the furnace top pressure and the furnace top equalization gas pressure is 1600 mm in the case of conventional equipment.
Aq, but in the case of this invention it is 300 mmAq. Therefore, the ability of the furnace top pressure equalization of the gas exiting the dust catcher or the bench scrubber is higher in the equipment of this invention, and compressed gas such as nitrogen, which is used auxiliary for furnace top pressure equalization, is higher. Only a small amount is required. As explained in detail above, in the blast furnace gas purification equipment of the present invention, a dual dust catcher equipped with a gravity sedimentation separation chamber and a centrifugal separation chamber or an electrostatic precipitator chamber is used as a bench scrubber, an electrostatic precipitator, and a moving packed bed. Since it is installed before the dust collector or electrostatic coagulation type moving packed bed dust collector, the installation space of the entire equipment is small and it is extremely economical. moreover,
There is little wear on the members of the bench lily scrubber, and the pressure loss of the entire equipment is small, so energy savings can be achieved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams of conventional blast furnace gas cleaning equipment. FIG. 3 and FIG. 4 are configuration diagrams of the blast furnace gas cleaning equipment according to the present invention. FIG. 5 is a longitudinal sectional view showing an example of a dual dust catcher used in the equipment of the present invention. FIG. 6 is a partially sectional view showing another example of the dual dust catcher.
FIG. 7 is a longitudinal cross-sectional view showing still another example of the duplex dust catcher. FIG. 8 is a sectional view taken along line A--A in FIG. 7. FIG. 9 is a longitudinal sectional view showing an example of a dual dust catcher having an electrostatic dust collection chamber instead of a centrifugation chamber. 10 and 11 are cross-sectional views taken along the lines AA and BB in FIG. 9, respectively. FIG. 12 is a sectional view showing another example of the structure taken along the line AA in FIG. 9. 1... Blast furnace, 2... Inlet pipe, 3... Dust catcher, 4, 15... Outlet pipe, 5, 8, 17...
Bench lily scrubber, 6...Semi-clean gas pipe, 7,
16...Furnace top pressure equalization pipe, 9,18...Clean gas pipe,
10, 19...Electrostatic precipitator, moving packed bed dust collector or electrostatic coagulation type moving packed bed dust collector, 21,
41, 51, 71... airtight container, 22, 42, 5
2,72...Dusthopper, 23,43,53,
73...Gravity sedimentation separation chamber, 24, 47, 55, 7
4...Clean gas chamber, 27, 48, 59, 75...
Inlet duct, 28, 49, 60, 76... Outlet duct, 29... Cyclone, 44, 54... Centrifugal separation chamber, 78... Electrostatic dust collection chamber, 79... Dust collection electrode, 80... Discharge wire , 21A, 41A, 51A,
71A...Gravity sedimentation separation chamber outer shell.

Claims (1)

[Scope of Claims] 1. In a blast furnace gas purification equipment provided with a primary dust catcher and a secondary dust collector on the downstream side of the primary dust catcher, a gravity settling separation chamber is installed from below in a casing constituting the primary dust catcher. , a centrifugal separation chamber is provided independently, a gas introduction pipe is provided in the gravity sedimentation separation chamber, and the outlet end of the gravity sedimentation separation chamber is formed to communicate with the inlet end of the centrifugation chamber, and the gas introduction pipe A blast furnace gas cleaning equipment characterized by communicating the top of the blast furnace, the outlet end of the centrifuge chamber, and a secondary dust collector. 2. In a blast furnace gas purification facility equipped with a primary dust catcher and a secondary dust collector on the downstream side of the primary dust catcher, a gravity sedimentation separation chamber and an electrostatic precipitator are installed from below in the casing constituting the primary dust catcher. A gas introduction pipe is provided in the gravity sedimentation separation chamber, and the outlet end of the gravity sedimentation separation chamber is formed to communicate with the inlet end of the electrostatic precipitator chamber, and the gas introduction pipe and the blast furnace Blast furnace gas cleaning equipment characterized by communicating the outlet end of the electrostatic precipitator chamber at the top of the furnace with a secondary precipitator.