JPS5955332A - Dust collecter for high-temperature gas - Google Patents

Abstract

PURPOSE:To prevent dewing in a dust hopper, by arranging a heat-insulating material and a heating pipe in the dust hopper. CONSTITUTION:A gas containing dust introduced directly from a blast furnace is discharged from the bottom of an introducing pipe 12, and flows into filter bags 15 while dropping coarse dust into the dust hopper. Fine dust is removed by the filter bags 15 and the gas is supplied to the outside as the clean gas. At the beginning of operation after a shutdown, a control valve 33 is opened and steam is supplied to a heating pipe 31 to heat the wall surface and the inner part of a dust hopper 10a. For the purpose of maintenance of a constant temperature, the whole body of a casing 10 is covered with heat-insulating materials 30. Gas thermometers 34, 35 are arranged at the inlet and the outlet. If there is a fear of dewing from the temp., heating is carried out. An electric heater or the like is used as a heating method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust collector for high temperature gas such as blast furnace gas. has been established. For example, taking a bag filter as an example, as shown in FIG. 15, 15, etc., the entire casing 10 is covered with a heat insulating material 50.

However, when starting up the operation after a shutdown, high-temperature gas is blown into the cold casing 10 and internal space, so moisture in the gas condenses and accumulates on the inner wall surface of the hopper part 10a. Otherwise, it gets stuck on the lower support plate 17 or the like. The moisture adhering to the lower support plate 17 and P cloth 15 will evaporate by blowing high-temperature gas afterwards, and there will be no problem with dust collection, but the condensed water that has accumulated in the hopper 5310a will flows down and sinks into the dust D. In this case, the dust D provides insulation and evaporation does not occur. By the way, during operation, the upper temperature of the hopper part 10a is 1
When the temperature is about 10 to 120℃, the internal temperature of the dust) D may reach about 40℃. Also, when blast furnace gas or exhaust gas from a sintering machine is targeted, Fe, CaO1S in the collected dust Contact with i 02 and cause a crosslinking phenomenon above the pulp (■) of the cutting device, which causes the dust D to stop flowing down even though the valve (■) is open, and eventually the pulp is cut out. Furthermore, if the gas contains S, the condensed water will become S.
It may react with other substances, leading to internal corrosion.

The present invention was proposed in order to solve the above problems, and its purpose is to prevent dew condensation and smoothly cut out the collected dust, and also to prevent the internal gas temperature from decreasing. An object of the present invention is to provide a dust collector for high-temperature gas.

The present invention will be explained below using a specific example of a bag filter.This bag filter has 91 cylinders, which is different from the conventional multi-cylinder bag filter. Reference numeral 10 denotes a casing, which is supported by a pedestal 11. Also casing 10
A dust-containing gas introduction pipe 12 extends from the upper part of the central part of the cylinder, and its lower end is opened at a position below the center. For example, six vertical partition walls 13 are provided in the radial direction from the dust-containing gas introduction pipe 12, partitioning the space between the introduction pipe 12 and the casing 10, and forming six dust removal chambers 14.
A to 14F are configured. Furthermore, the partition wall 13 has a length from the top of the casing 10 to near the lower end of the introduction pipe 12.

A large number of pieces of cloth 15 are arranged inside the dust removal chambers 14A to 14F, and are suspended from a black plate 16 having gas holes. 1
7 is a support plate for the lower part of the cloth 15. Further, an annular pipe 18 is disposed around the upper part of the casing 10 and communicates with a clean gas discharge pipe 19.
are each dust removal chamber 14A to 14FK filtration valve 20.20...
It communicates through a branch pipe with. Furthermore, the annular tube 1
8, a backwash fan 21 is installed on the pedestal 11, and an outlet pipe of the backwash fan 21 communicates with each dust removal chamber 14A to 14F via a backwash valve 22. There is.

On the other hand, the lower part of the casing 10 is a reverse rust-shaped hopper part 10a, and upper and lower limit level detectors 23 and 24 are provided to detect the level of dust accumulated there. Furthermore, a rotary valve 25, a ball valve 26, an intermediate hopper 27, a rotary valve 28, and a ball valve 29 are provided in this order at the lower part of the hopper part 10a to constitute dust cutting equipment. The intermediate hopper 27 is provided with upper and lower limit level detectors 23' and 24'. Note that the entire casing 10 is covered with a heat insulating material.

In the bag filter constructed in this way, when removing dust, a dust-containing gas is introduced directly from the blast furnace or a dust-containing gas G is introduced through a dust catcher. is the introduction tube 1
2 and is discharged from its lower end. The discharged dust-containing gas causes the accompanying dust to fall into the hopper part 10a, while cleaning the 15 groups of cloths in the dust removal chambers other than the dust removal chamber during backwashing (the dust removal chamber 14D in the tooth claw example) from the inside to the outside. At that time, dust is collected by the group of f cloths 15, and the gas becomes clean gas, which passes through the filtration valves 20 other than the filtration valves corresponding to the dust removal chamber during backwashing, and is purified via the annular pipe 18. From the gas discharge pipe 19, it becomes clean gas G1 and is sent to the next equipment.

At this time, a part of the clean gas is taken in by the backwash fan 21 and blown into the already contaminated dust removal chamber 14D through the corresponding backwash valve 22. As a result, the clean gas passes through the group of P cloths 15 in the dust removal chamber 14D from the outside to the inside, and is discharged from the lower part of the dust removal chamber 14D together with the dust captured in the P cloth 15. At this time, the dust falls into the hopper part 0a due to gravity. Some of the dust is
Some of them accompany the dust-containing gas discharged from the introduction pipe 12. Thus, while dust is being removed in the five dust removal chambers, backwashing is performed in the dust removal chamber 14D.

When the dust accumulated in the hopper part 0a reaches level 14, the rotary valve 25 and the ball valve 26 are opened based on the signal from the upper limit level detector 23, and the dust is cut out to the intermediate hopper 27. continues until it reaches L level.

A similar operation applies to the intermediate hopper 27 in relation to its lower rotary valve 28 and ball valve 29.

30 is a heat insulating material that covers the entire casing 10. In the present invention, in view of the occurrence of dew condensation as described above, a heating pipe 31 is disposed between the outer surface of the dust hopper portion 10a and the heat insulating material 30. Steam is supplied to the heating tube 31 from a steam source 32 via a control valve 33. Further, an inlet gas thermometer 34 is provided in the gas introduction pipe 12, and an outlet gas thermometer 35 is provided in the gas discharge pipe 19.
Furthermore, an external surface thermometer 36 is provided on the transfer path of the collected dust, and these signals are taken into a dew condensation prevention control device 37.

When the operation starts up after the shutdown, the control valve 33 is opened and steam is passed through the heating pipe 31 to heat the wall surface and the inside of the dust hopper part 10a. Thereby, moisture that tends to condense on the inner wall surface of the dust hopper portion 10a can be evaporated.

In this case, heating may be performed only when there is a risk of condensation while taking into account the inlet and outlet gas temperatures and the external surface temperature of the transfer path. In addition to preventing dew condensation, heating can also be performed to control the gas temperature inside the bag filter.

On the other hand, in the above example, a heating medium is passed through the heating tube as the heating means, but an electric heater or the like may also be used.

The heating means may be provided throughout the casing. In addition, when collecting dust from blast furnace gas, dew condenses at about 70 to 60 degrees Celsius, and when it comes to combustor exhaust gas, it condenses at about 90 degrees Celsius, so the transfer path for the collected dust is heated to a higher temperature. Furthermore, although the above example is an example of a cylindrical bag filter, the present invention can of course be applied to a rectangular bag filter or an electrostatic precipitator.

As described above, in the present invention, since the heating means is provided at least in the transfer path of the collected dust to the cutting equipment, it is possible not only to reliably prevent dew condensation but also to perform smooth cutting of the dust. It can also be used to heat the gas inside the casing.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing how condensation occurs in a bag filter, Fig. 2 is a longitudinal cross-sectional view showing an example of the dust collector of the present invention, and Fig. 3 is a collection shown in Fig. 2. The main part enlarged sectional views of the dust transfer path, FIGS. 4 to 6 are IV-IV, v-
v and ■-■ line arrow view 0 10...Casing 10a...Dust hole part 3
0...Insulation material 31...Heating tube 32...Steam source
33... Control valve 34. 35... Gas thermometer 36... External surface thermometer 37... Condensation prevention III control device patent applicant Sumitomo Metal Industries, Ltd. Hitachi Zosen Corporation Figure 1 Figure 3 Figure 2 Figure 4 Figure 5 Figure 6 190-

Claims (1)

[Claims] (1) Introduce blast furnace gas to a bag filter complete dust collector,
In a dust collector that is provided with a transfer path that leads the collected dust to a cutting device located below the dust collector, and in which the transfer path is provided with a heating means, the external surface temperature of the transfer path and the inlet and outlet of the gas concerned are determined. A dust collector for high-temperature gas, characterized in that the temperature of the gas is constantly detected, and the detected temperature is used to operate the heating means by means of a dew condensation prevention control device.