JPS6133882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blast furnace exhaust gas treatment apparatus equipped with a dry dust collecting section using a heat-resistant granular filter material such as sand, gravel, ceramics, or refractory material.

Since the blast furnace exhaust gas contains about 10 to 20 g/Nm ³ of dust, the dust content is reduced to about 5 mg/Nm ³ by removing the dust. To give an example of a conventional dust removal method, first a dust catcher is used to remove coarse particles to a dust content of 5 to 10 g/ ^Nm3 , and then a bench lily scrubber is used to remove the dust. Finally, there is a method in which an electrostatic precipitator is used to reduce the dust content to 5 mg/Nm ³ or less. That is, the blast furnace exhaust gas that has been removed in three stages is temporarily stored in a gas holder and used as fuel.

This conventional method uses a dust catcher,
In addition to requiring a bench scrubber, an electrostatic precipitator, and a three-stage dust collection system, the wet dust collection method evaporates moisture and increases the amount of gas, which increases the size of downstream equipment. At the same time, moisture is included in the recovered fuel gas, which reduces the calorific value per unit capacity.Additionally, a treatment device for gas cleaning wastewater is required, and the gas is cooled to around 50℃, which reduces the amount of blast furnace exhaust gas. However, it has disadvantages such as the inability to recover sensible heat.

In addition, as shown in Japanese Patent Application Laid-Open No. 129407/1983, when blast furnace gas is cleaned using a wet gas purifier, gas-associated mist is created in the system between the wet gas purifier and the top pressure regulator of the blast furnace. A blast furnace gas cleaning system has been proposed that includes a resistor that removes gas and suppresses gas flow. Specifically, in this system, resistance parts 7 and 8 are formed within the secondary ventilise scrubber 4. The resistor parts 7 and 8 are formed by filling a filler 9 such as a ring made of ceramic, metal, or synthetic resin, as shown in lines 17 to 18 of the upper right column on page 2 of the publication. In other words, it has a structure in which a mist separator is attached to the downstream side of a bench uri scrubber, which is a wet type dust collector.

In this way, the method described in JP-A-50-129407 is also a wet dust collection method, so water still evaporates and the amount of gas increases, which requires downstream equipment to become larger and the collected gas to be collected. The heating value per unit capacity of the blast furnace is small, a treatment device for gas cleaning wastewater is required, and the sensible heat of the blast furnace exhaust gas cannot be effectively recovered.

The present invention has been made to solve the above-mentioned drawbacks, and is made by filling a blast furnace exhaust gas duct with a granular heat-resistant filter material such as sand, gravel, ceramics, or refractory between supports in the form of panels or layers. A dry filtration and dust collection unit with a dust collection layer is connected, and this dry type dust collection unit removes dust with high performance and low pressure loss, and high temperature and dry clean fuel gas is released from the exhaust gas outlet of the dry type dust collection unit. After the pressure and temperature energy of the blast furnace exhaust gas is recovered by an energy recovery section installed in parallel with the furnace top pressure control valve without combustion, the gas is temporarily stored in a gas holder and used as fuel. The purpose of the present invention is to provide a processing device for blast furnace exhaust gas, which can be used as a fuel, or directly store clean fuel gas from a dry dust collecting section in a gas holder and use it as fuel without recovering energy. It is something.

The blast furnace exhaust gas treatment apparatus of the present invention will be described with reference to the drawings. The blast furnace exhaust gas duct 2 has a dust collection layer 7 formed by filling a granular heat-resistant filter material between supports in the form of a panel or a layer. The dry dust collection unit 4 is connected to the furnace top pressure control valve 14 provided in the exhaust gas duct on the exhaust gas outlet side of the dry dust collection unit, and hot and dry clean fuel is supplied from the exhaust gas outlet of the dry dust collection unit in parallel. It is characterized by the provision of an energy recovery section 16 for extracting gas and recovering the pressure energy and temperature energy of the clean fuel gas.

Hereinafter, the configuration of the present invention will be explained based on embodiments shown in the drawings. FIG. 1 shows an embodiment of the blast furnace exhaust gas treatment apparatus of the present invention. 1 is a blast furnace, a blast furnace exhaust gas duct 2 is connected to the top of the blast furnace 1, and a coarse particle separation unit such as a cyclone, that is, a dust catcher 3 is connected to the exhaust gas duct 2.
A dry dust collection unit 4 is connected to the dry dust collection unit 4 through which a heat-resistant filtration material 5 in the form of granules such as sand, gravel, ceramics, and refractories is connected through metal louvers, wire mesh,
It is constructed by providing inside a dust collection layer 7 which is movably filled and held in a panel or layered manner continuously or intermittently between heat-resistant supports 6 such as metal porous plates. This dust collection layer 7 is provided at right angles or substantially at right angles to the exhaust gas flow. A filter material supply hopper 8 is connected to the upper end of the dust collection layer 7.
A filter material/dust ejector 10 is provided at the bottom end of the dust collection layer 7.
is connected. This filter media/dust discharger 10 is connected to the filter media supply hopper 8 via a filter media/dust separation/transfer device 11, and after separating the filter media and dust that are continuously or intermittently extracted, It is constructed so that the separated filter media can be transported to a high place and recycled for reuse. As the filter material/dust separation/transfer device 11, a vibrating sieve 1 is used as an example.
It is constructed by combining a filter material/dust separator such as 2 and a transfer device 13, which is a bucket elevator or a device having a structure in which a blower is connected to the lower part and the pressurized gas is used to transfer the air to high places. Although not shown in the figure, after the filter medium with dust attached is transported to a high place using pressurized gas, the filter medium and the dust-containing gas are separated using a cyclone or the like. It is also possible to configure a transport device.

The exhaust gas duct on the exhaust gas outlet side of the dry dust collecting section 4 is provided with a furnace top pressure regulating valve 14 for regulating the furnace top pressure of the blast furnace to a constant level, and the exhaust gas duct downstream of this furnace top pressure regulating valve 14 is provided. is gas holder 15
connected to. An energy recovery unit 16 consisting of a turbine or the like is provided in parallel with the furnace top pressure control valve 14 and connected to the exhaust gas duct, and is configured to recover the pressure energy and temperature energy of the blast furnace exhaust gas. 17 is a furnace top pressure control valve 14
18 is a dust storage tank connected to the lower part of the vibrating sieve, and 20 is a hot air blower connected to the lower part of the blast furnace.

In the blast furnace exhaust gas treatment device configured as described above, CO, CO ₂ ,
The blast furnace exhaust gas is composed of H ₂ , N ₂ , etc. and contains dust of about 10 to 20 g/Nm ³ . First, coarse particles are removed in the dust catcher 3 (the dust content is 5 to 10 g/Nm 3 ).
g/Nm ³ ), then introduced into the dry dust collecting section 4 and removed to a dust content of 5 mg/Nm ³ or less.
That is, the dust in the exhaust gas adheres to the surface of the granular heat-resistant filter material and is retained in the spaces between the filter materials, resulting in high-performance dust collection with low pressure loss. The high temperature (around 150 to 250 degrees Celsius) and dry clean fuel gas from which dust has been removed undergoes pressure adjustment by the furnace top pressure control valve 14, and at the same time is introduced into the energy recovery section 16 where pressure energy and temperature energy are converted. It will be collected.
In this case, the exhaust gas pressure at the inlet of the dry dust collecting section 4 is 2
However, since the pressure loss in ^the dust collection layer is small, the exhaust gas pressure at the outlet of the dry dust collection section is close to 2 kg/cm ² g. The exhaust gas exiting the energy recovery section 16 is temporarily stored in the gas holder 15 and then used as fuel. On the other hand, granular heat-resistant filter media with dust attached
The dust is extracted continuously or intermittently by a dust discharger 10, and the filter medium and dust are separated by a vibrating sieve 12. The separated heat-resistant filter material in the form of granules is transferred to a high place by the transfer device 13 to the filter material supply hopper 8 for circulation and reuse, and the separated dust is temporarily stored in the dust storage tank 18 and then used as a sintering raw material and reduced. Used as raw material for pellets, etc.

Next, another embodiment of the apparatus of the present invention will be described based on FIG. 2. In this embodiment, instead of configuring the dust collection section from a coarse particle separation section such as the dust catcher 3 and a filtration type dust collection section 4 as described above, a filtration type dust collection section is constructed without providing a dust catcher. It is constructed from only the dust part 4. The filtration type dust collection section 4 can not only handle high concentration dust but also withstand high temperatures, so it has the advantage of being able to deal with raw running (blow-through) etc. without providing a coarse particle separation section. are doing. Other configurations and operations are the same as in FIG. 1.

In addition, in the example shown in FIG. 3, the dry clean fuel gas discharged from the dry filtration type dust collection unit 4 is used directly or through a gas cooler (not shown) without providing an energy recovery unit. It is configured to be stored in a holder 15. Other configurations and operations are similar to those in FIG. 1 or 2.

In addition to the above, a dust collection layer formed by filling an agglomerated heat-resistant filter material with a larger particle size than the agglomerated heat-resistant filter material 5 used for this dust collection layer 7 adjacent to the upstream side of the dust collection layer 7 In some cases, a dry dust collecting section is formed by providing a dry dust collection section to roughly collect large particle size dust from the blast furnace exhaust gas. Further, reduced pellets, sintered ore, etc. may be used as the granular heat-resistant filter material. In this case, there is an advantage that the granular heat-resistant filter material with dust attached to it extracted from the dry dust collecting section can be used as a raw material without being separated.

As explained above, in the blast furnace exhaust gas treatment device of the present invention, a granular heat-resistant filter material such as sand, gravel, ceramics, sintered ore, and reduced pellets is placed in a panel or layered manner between supports in a blast furnace exhaust gas duct. Since the filled dry filter type dust collector is connected to treat high concentration dust with a high dust collection rate, an expensive electrostatic precipitator etc. is installed downstream of the furnace top pressure control valve as in the past. There is no need to do so. This dry filtration type dust collection section can easily perform high pressure gas/air sealing. In addition, conventionally, a wet dust collection method was used, so the recovered gas contained a large amount of moisture, but since the device of the present invention uses a dry dust collection method, blast furnace exhaust gas can be recovered as dry gas. As a result, the volume of the recovered gas is small and the water pressure is low, making it possible to obtain high-calorie gas, as well as making it possible to downsize downstream equipment such as ducts and gas holders, and eliminating the need for water treatment equipment. It has the effect that

Furthermore, since the dust (accompanying iron oxide) can be recovered in a dry state, it can be used as a raw material for high-quality reduced pellets. Furthermore, in the conventional wet dust collection method, the gas was cooled to around 50℃, making it impossible to recover heat, but in the device of the present invention, the temperature at the outlet of the dry dust collection section is as high as 150 to 250℃. Moreover, this dry dust collecting section has a lower pressure drop than a conventional dust collector, so it has the effect that the temperature energy and pressure energy of the exhaust gas can be effectively recovered in the energy recovery section.

[Brief explanation of the drawing]

Fig. 1 is a systematic explanatory diagram showing one embodiment of the blast furnace exhaust gas treatment device of the present invention, Fig. 2 is a systematic explanatory diagram showing another embodiment, and Fig. 3 is a systematic explanatory diagram showing another example. It is a diagram. DESCRIPTION OF SYMBOLS 1... Blast furnace, 2... Blast furnace exhaust gas duct, 3... Dust catcher, 4... Dry type dust collection part, 5... Granular heat-resistant filter material, 6... Heat-resistant support, 7... Dust collection layer,
8... Filter material supply hopper, 10... Filter material/dust discharge machine, 11... Filter material/dust separation/transfer device, 1
2... Vibration sieve, 13... Transfer machine, 14... Furnace top pressure control valve, 15... Gas holder, 16... Energy recovery section, 18... Dust storage tank.

Claims (1)

[Claims] 1. A dry dust collection section having a dust collection layer formed by filling a granular heat-resistant filter material between supports in the form of panels or layers is connected to the blast furnace exhaust gas duct, and the exhaust gas duct on the exhaust gas outlet side of this dry dust collection section is connected to the blast furnace exhaust gas duct. An energy recovery unit is installed in parallel with the furnace top pressure control valve installed in the furnace to extract high-temperature and dry clean fuel gas from the exhaust gas outlet of the dry dust collection unit and recover the pressure energy and temperature energy of the clean fuel gas. A blast furnace exhaust gas treatment device characterized by being provided with.