JPH0222020Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to a device for dry dust collection of gas generated from a high-pressure blast furnace which has been primarily dust-collected with a coarse dust remover. (Prior technology) In recent years, in order to recover more of the gas energy (pressure and temperature) generated from high-pressure blast furnaces as electricity using a turbine, electrostatic precipitators have been introduced in place of conventional high-pressure moisture-loss dust collectors such as ventilure scrubbers. Low pressure loss dry dust collectors such as (see Japanese Patent Application Laid-Open No. 54-40207) or bag filters (see Japanese Patent Application Laid-Open No. 59-59234) have come to be used as dust collectors for blast furnace gas. I came. However, in order to discharge the dust collected by the dry dust collector out of the system under high pressure from the toxic blast furnace gas atmosphere and transport it to the dust hopper, it is necessary to take sufficient precautions to prevent gas leakage. As shown in Publication No. 59-59234 and FIG. 3, a pressure equalizing valve 3 is installed below the hopper 32 of the dust collector 31.
3. An intermediate hopper 35 having an exhaust pressure valve 34 is provided, and when dust is to be discharged from the intermediate hopper, the internal high-pressure blast furnace gas is opened through the exhaust pressure valve 34, guided to the dust hopper 39 through the exhaust pressure pipe 36, and then passed through the dust classifier 40. After the dust was collected, it was dissipated into the atmosphere, lowering the pressure inside the intermediate hopper 35 to atmospheric pressure. The dust cut out from the intermediate hopper 35 is
The dust hopper 3 is transported by mechanical transport devices such as a screw conveyor 37 and a bucket elevator 38.
It was being transported to 9. (Problems to be solved by the invention) As mentioned above, in the conventional dust transport device, there is an intermediate hopper above and below the screw conveyor, a shutoff valve to equalize the pressure above and below the hopper, a rotary valve to cut out the dust, etc. However, the overall height of the dust collector becomes taller, making the equipment expensive. In addition, there were many moving mechanical parts such as valves and screw conveyors, which required a considerable amount of maintenance work. (Means for Solving the Problems) The present invention is a dry dust collector for a high-pressure blast furnace, which solves the above-mentioned problems and has a dust transportation device that is inexpensive and requires almost no maintenance. In the present invention, a dust discharge valve 16 is provided in the lower hopper 11 of the dust collector 3, and a disperser 17 is provided below the dust discharge valve 16, and the gas inlet of the disperser 17 and the dust collector outlet pipe 13 are connected by piping, and the outlet of the disperser 17 and the dust discharge valve 17 are connected to the dust collector 17. 5 is connected to the dust transport pipe 4, and a part of the dust collector outlet gas is blown into the disperser via a booster blower 20, so that the collected dust in the dust collector 3 can be air-transported to the dust hopper 5. This is a dry dust collector for blast furnaces. The basic concept of the present invention will be explained below using FIG. 1. (Function) In a high-pressure blast furnace, the furnace top pressure is approximately 1 to 3 kg/cm ² G.
There is almost the same pressure before and after the dry dust collector 3. Therefore, the lower hopper 11 of the dust collector and the dust hopper 5 whose internal pressure is approximately atmospheric pressure are connected by the dust transport pipe 4, and the gas partially extracted from the dust collector outlet pipe 13 is passed through the booster blower 20 to a level slightly higher than the internal pressure of the dust collector 3. By increasing the height of the dust collector and feeding it as a transporting gas from the disperser 17, the air flow can be reliably transported through the collection duct in the dust collector to the dust hopper 5 due to the difference in pressure between the pressure inside the dust collector and the pressure inside the dust hopper. Also, a dust discharge valve 16 attached to each dust collector
By sequentially opening the chambers one by one and blowing the conveying gas only into the corresponding disperser 17, the amount of gas extracted from the dust collector outlet pipe 13 can be reduced, and the amount recovered by the energy recovery turbine can be increased.
Furthermore, the capacities of the boost blower 20 and the dust classifier 6 can also be reduced. (Embodiment) Fig. 2 shows an embodiment of this invention as a dry dust collector in which a bag filter is adopted and the exhaust pipe of the dust hopper is connected to a clean gas pipe. The blast furnace gas separated from the rough duct by the coarse dust remover 2 is introduced into the dry dust collector 3 through the inlet gas pipe 12, and after reaching a cleanliness level of 5 mg/Nm ³ or less, it passes through the outlet gas pipe 13 and is sent to the energy recovery turbine. Guided by 9. In this embodiment, the dry dust collector 3 is divided into five chambers 3-a.
The four chambers from 3-d to 3-d are collecting dust, and 3-e is shaking off dust on the cloth, which is a so-called backwashing state. For backwashing, close the dust collector outlet valve 14-e, open the backwash valve 15-e, and send the clean gas from the dust collector outlet pipe 13 whose pressure has been increased by the booster blower 20 to the dust collector 3.
- This is done by sending it into e. Repeat this same operation one by one for the other four chambers to dust off the dust. When the dust discharge valve 16-e is opened, the dust brushed off in the dust collector 3-e will be reduced to a gas pressure inside the dust collector (approximately the same as the blast furnace top gas pressure, approximately 1 to 3 kg/cm ²
G) and the gas pressure in the dust hopper 5 (approximately 0.1
Kg/cm ² G), a high concentration is discharged from the hopper 11-e, but if the concentration remains high, the pressure loss will be large, and it may not be possible to convey it with the above pressure difference. vessel) 17-e
The blast furnace gas for transportation is supplied, diluted to a low concentration, and reliably transported to the dust hopper 5 through the dust discharge pipe 4-e. Incidentally, the dust is discharged periodically at the time of backwashing, so that the dust does not accumulate in the lower hopper 11. The conveying blast furnace gas to be supplied to the disperser 17-e is supplied into the disperser by using the blast furnace gas pressurized by the booster blower 20 and opening the valve 18-e. Similar to the backwashing operation of the dust collector, the dust discharge operation described above is performed sequentially one chamber at a time, so that the dust in the dust collectors 3-a to 3-e can be transported to the dust hopper 5 with a small amount of carrier gas. In this embodiment, dust transport pipes 4-a to 4-e were provided in each chamber to prevent dust clogging.
Furthermore, fluidization pipes 19-a to 19-e were provided for blowing clean gas into the dust collector to prevent clogging at the exits of the hoppers 11-a to 11-e and to smoothly cut out dust into the dust transport pipe. Most of the dust carried into the dust hopper 5 settles by gravity within the hopper 5, and fine dust is separated from the gas by a dust classifier 6 provided at the top. The purified blast furnace gas is connected to a clean gas pipe 10 downstream of the furnace top pressure control valve 8, that is, downstream of the energy recovery turbine 9 (approximately 0.1 kg/cm ² G pressure), through an exhaust pipe 7 to remove toxic gas. can be collected without releasing it to the outside. (However, it may be released into the atmosphere if it is a safe place.) In addition, an orifice 21 and a control valve 22 are installed in the system of the exhaust pipe 7, and the dust collectors 3-a to 3-
When the amount of dust discharged from e is small, a large amount of blast furnace gas flows (opening state), and the dust classifier 6
Performs air volume control to prevent overload. When discharging dust from the dust hopper 5, the airflow transport of the collected dust is stopped, that is, the dust discharge valve 16 and the carrier gas valve 18 provided at the bottom of the dust collector are fully closed in all chambers. The pressure inside the dust hopper is lowered to almost atmospheric pressure, eliminating the risk of the internal blast furnace gas leaking to the outside together with the dust, and then being discharged to a truck, etc. A calculation example when the above idea is applied to a 5000m Class ³ blast furnace is shown below.

【table】

[Table] (Effects of the invention) As explained above, this invention connects the hopper of each dust collector divided into multiple chambers with a pipe and introduces clean gas from the disper as a carrier gas, and airflows the collected dust to the hopper. This is a dry type dust collector that is transported and requires fewer expensive mechanical parts and the overall height of the dust collector is lower, resulting in lower equipment costs. Additionally, since there are fewer moving machines than conventional mechanical transportation systems, there is a significant reduction in maintenance work.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the concept of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention in which a bag filter is adopted as a dry dust collector, and FIG. 3 is a diagram of a conventional dust collection system. 1...Blast furnace, 2...Rough dust remover, 3,3-a~3
-e, 31...Dry dust collector, 4, 4-a to 4-e
...Dust transport pipe, 5,39...Dust hopper, 6,40...Dust classifier, 7...Exhaust pipe,
8...Furnace top pressure control valve, 9...Energy recovery turbine, 10...Clean gas pipe, 11, 11-a~1
1-e, 32... Lower hopper, 12... Inlet gas pipe, 13... Outlet gas pipe, 14-a to 14-e
... Outlet valve, 15-a to 15-e... Backwash valve, 16, 16-a to 16-e... Dust discharge valve, 17, 17-a to 17-e... Disperser, 18-a ~18e... Carrier gas valve, 19a~
19e... Fluidization pipe, 20... Boosting blower,
21... Orifice, 22... Control valve,
33...Pressure equalization valve, 34...Exhaust pressure valve, 35...Intermediate hopper, 36...Exhaust pipe, 37...Screw conveyor, 38...Bucket elevator.

Claims (1)

[Scope of utility model registration request] Dust discharge valve 1 is installed in the lower hopper 11 of the dust collector 3.
6 and a disperser 17 is provided below it, and the gas inlet of the disperser 17 and the dust collector outlet pipe 1 are connected to each other.
3 with piping, and the outlet of the disperser 17 and the dust hopper 5 are connected with the dust transport pipe 4, and a part of the dust collector outlet gas is blown into the disperser via the booster blower 20, and the collected dust in the dust collector 3 is transferred to the dust hopper. 5. A dry type dust collector for a high pressure blast furnace, characterized in that it is formed so as to be able to be transported by airflow.