JP2000317234A - Bag type dust collector and its operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bag type dust collector and its operating method high in adsorption efficiency of the harmful material such as HCl. SOx and dioxins. SOLUTION: The bag type dust collector 10 is constituted so that a exhaust side of filter chamber 14-16 provided respectively with the filter fabrics 11-13 for filtering exhaust gas may be connected to a common inlet side of a dust collector main body housing the plurality of filter chambers 14-16 by interposing exhaust gas return valves 29-31 and an exhaust gas return fan 32 connected to these valves. In the operating method of the bag type dust collector 10, the treated gas passing the filter chambers 14-16 just after back washing is returned to the common inlet side of the dust collector main body by interposing exhaust gas return valves 29-31 and the exhaust gas return fan 32 connected to these valves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a bag for removing dust to be treated and performing a reaction treatment in a state where a powdery reaction aid and / or adsorbent is attached to the surface of a filter cloth to form a filtration layer. The present invention relates to a dust collector and an operation method thereof.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional bag type dust collector 60, which has a plurality of filtration chambers 64 to 66 in which cylindrical filter cloths 61 to 63 are arranged. An intake duct 67 through which combustion exhaust gas flows is provided on the inlet side of the filtration chambers 64 to 66. A tank 69 for mixing a reaction aid and / or an adsorbent into the processing gas via a rotary valve 68 in the middle of the intake duct 67. Is provided. Exhaust gas outlet valves 71 to 73 are provided on the exhaust side of each of the filtration chambers 64 to 66, and exhaust gas is discharged to the atmosphere via a suction fan 74. On the other hand, a backwash fan 75 is provided on the exhaust side of the bag type dust collector 60, and supplies air into the filtration chambers 64 to 66 through the backwash valves 76 to 78 to adhere to the filter cloths 61 to 63. Dust is removed. Each processing step of this bag type dust collector 60 is shown in FIG. 5, and each step of the filtration chamber 66 is shown in Table 1.
Normally, the flue gas is continuously processed by alternately performing filtration and backwashing. Reference numerals 79 to 81 denote dust discharge valves.

[0003]

[Table 1]

[0004]

However, in the bag type dust collector 60 according to the conventional example, the filter cloth (one of 61 to 63) immediately after the backwashing treatment does not have a sufficient filtration layer. Even if a filtration layer is formed, the filtration layer is thin and the pressure loss is lower than that of other filtration chambers. Therefore, a large amount of gas flows into this filtration chamber, and the adsorption of HCl, SOx, and dioxins decreases. was there. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bag type dust collector having a high adsorption efficiency of harmful substances such as HCl, SOx, and dioxins, and an operation method thereof.

[0005]

According to a first aspect of the present invention, there is provided a bag-type dust collector, wherein an exhaust side of a filtration chamber provided with a filter cloth for filtering exhaust gas is connected to an exhaust gas return valve and the exhaust gas return valve. The processing gas passing through the filtration chamber immediately after backwashing is connected to the common inlet side of the dust collector body that houses the plurality of filtration chambers via an exhaust gas return fan, and the processing gas is passed through the exhaust gas return valve and the exhaust gas return fan. It is returned to the common inlet side of the dust collector body. Further, the operating method of the bag type dust collector according to the second invention has a filtration chamber provided with filter cloth for filtering exhaust gas, and the filter cloth in each of the filtration chambers has a powdery reaction aid and / or adsorption. A method of operating a bag-type dust collector in which a step A for attaching an agent and a step B for backwashing the filter cloth in each of the filtration chambers are sequentially performed, wherein the backwashing is performed after the filter cloth in the filtration chamber is backwashed. The process has a C step of returning the exhaust gas from the filtration chamber to the inlet side of the gas to be treated of the bag type dust collector, thereby preventing discharge of untreated gas on the exhaust side. Here, in the operation method of the bag type dust collector, in the step C, the exhaust gas outlet valve provided in the middle of the exhaust side of the filtration chamber and the suction fan is closed, and the exhaust gas outlet valve is provided on the exhaust side of the filtration chamber. The exhaust gas return valve is opened and the exhaust gas return fan provided downstream of the exhaust gas return valve performs the operation.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment embodying the present invention will be described. Here, FIG. 1 is a schematic explanatory view of a bag type dust collector according to a first embodiment of the present invention, FIG. 2 is an operation process diagram thereof, and FIG. 3 is a bag type dust collector according to a second embodiment of the present invention. FIG.

As shown in FIG. 1, a bag type dust collector 10 according to a first embodiment of the present invention has a plurality of filtration chambers 14 to 16 having bag-shaped filter cloths 11 to 13 for filtering exhaust gas.
Exhaust gas outlet valves 17 to 19 connected to the exhaust ports at the upper portions of the filtration chambers 14 to 16, respectively;
And dust discharge valves 21 to 23 disposed at the bottom of the conventional dust collector, but they are the same as those of the conventional bag type dust collector, and detailed description thereof will be omitted. A suction fan 24 is provided on the exhaust side of the exhaust gas outlet valves 17 to 19, and backwash valves 26 to 28 are connected to the exhaust side of each of the filtration chambers 14 to 16 through a backwash fan 25. Backwash the filter cloths 11 to 13 disposed in the respective filtration chambers 14 to 16 with the clean air that has passed through the dust collector 10, and discharge the blown-out dust from the lower dust discharge valves 21 to 23 to the outside. It is supposed to be. In this embodiment, the dust discharge valves 21 to 23 are two-stage valves that open and close alternately, but there are also rotary valves and screw feeders. Each of the filtration chambers 14 to 16 is housed in a dust collector main body (not shown) and has a common intake port connected to the intake duct 34.

Exhaust gas return valves 29 to 31 are provided on the exhaust side (exit side) of the filtration chambers 14 to 16, and these exhaust sides are connected to the intake port of an exhaust gas return fan 32. The exhaust side of the exhaust gas return fan 32 is connected via a flow meter 33 to an intake duct 34 connected to a common intake port (exhaust gas inlet) in the dust collector body of the bag type dust collector 10. A tank 36 filled with a reaction aid / adsorbent is connected to the intake duct 34 via a rotary valve 35, and by driving the rotary valve 35, C
Powder of a reaction aid / adsorbent such as a (OH) ₂ is gradually introduced into the intake duct 34. The powder of the reaction aid / adsorbent blown into the lower part of each of the filtration chambers 14 to 16 via the intake duct 34 adheres to the inner surfaces of the filter cloths 11 to 13.

Next, an operation method of the bag type dust collector 10 will be described with reference to FIGS. Focusing on the filtration chamber 16, during normal filtration, the exhaust gas outlet valve 19 is open, and the backwash valve 28 and the exhaust gas return valve 31 are closed. In this state, dust contained in the exhaust gas entering from the lower part of the filtration chamber 16 is captured by the filter cloth 13, and SOx and HCl contained in the exhaust gas are removed by the filter cloth 13.
Reaction adsorbent or adsorbent (eg, Ca (OH)
_It is absorbed by ₂ ) and becomes clean air, and is discharged from the filtration chamber 16. If dust adheres excessively to the filter cloth 13, the ventilation resistance increases, and this is detected by the pressure before and after the filter cloth 13 and the like, and a backwashing process is performed. In the process of the backwashing process, the exhaust gas outlet valve 19 and the exhaust gas return valve 31 are closed,
The backwash valve 28 is open. As a result, the clean air filtered by the bag type dust collector 10 enters the upper part of the filtration chamber 16 and the dust, the reaction aid and the adsorbent adhering to the filter cloth 13 are also removed and fall. The fallen dust, reaction aid and adsorbent are discharged to the outside by operating the dust discharge valve 23. In this process, the filtration chamber 16 does not filter the exhaust gas, and the other filtration chambers 14 and 1 do not.
5, the exhaust gas is filtered.

[0010]

[Table 2]

When the backwashing of the filter cloth 13 is completed, the process proceeds to a filter layer forming step. In this step, the exhaust gas outlet valve 19 and the backwash valve 28 are closed, the exhaust gas return valve 31 is opened, and the rotary valve 35 is operated to supply the reaction aid or adsorbent powder into the intake duct 34. As a result, the powder of the reaction aid and the adsorbent will be contained in the exhaust gas,
The filter cloth 13 is partially captured. At this time,
The gas passing through the filter cloth 13 is supplied to the common exhaust side of the exhaust gas of the dust collector main body of the bag type dust collector 10 through the exhaust gas return valve 31 and the exhaust gas return fan 32, that is, the inlet side of the gas to be treated. The unprocessed gas which has been incompletely filtered by the filter cloth 13 in the course of formation is not to the outside.
In addition, the gas which has been incompletely filtered is finally filtered by one or both of the filter cloths 11 and 12 operating simultaneously. As shown in FIG. 2, the processing is repeated for each of the filtration chambers 14 to 16 so that such processing does not overlap.

Next, a description will be given of a bag type dust collector 38 according to a second embodiment of the present invention. As shown in FIG. 3, the bag type dust collector 38 has filter cloths 40 a to 40
A dust collector main body 42 partitioned into individual filtration chambers 41a to 41d for each 0d, exhaust gas outlet valves 43a to 43d connected to exhaust ports of the filtration chambers 41a to 41d, respectively, and exhaust ports of the filtration chambers 41a to 41d. And exhaust gas return valves 44a to 44d respectively connected to the exhaust gas return valves 44a to 44d. The exhaust side of the exhaust gas outlet valves 43a to 43d is connected to the intake port of the suction fan 45, and the exhaust side of the exhaust gas return valves 44a to 44d is connected to the intake port of the exhaust gas return fan 46. The gas sucked by the suction fan 45 is discharged outside through the chimney, and the gas sucked by the exhaust gas return fan 46 is
It is introduced into an intake duct 48 connected to an intake port of a bag type dust collector 38 via a flow meter 33. On the other hand, the base of the pulse head 49 filled with compressed air is connected to the upper part of the filtration chambers 41a to 41d, and a diaphragm for pulsating compressed air to the filter cloths 40a to 40d at the time of back washing. Valves 50a to 50d are provided.

The operation method of the bag type dust collector 38 is the same as that of the bag type dust collector 10, but in the bag type dust collector 38, the diaphragm valves 50a to 50
d to open any one of the corresponding filtration chambers 41a to 41
d (hereinafter, referred to as filtration chamber A), and the filter cloths 40 a to 40 d (hereinafter, referred to as filter cloth A) in the filtration chamber A are backwashed. After the backwash of the filter cloth A is completed, a filter layer is formed on the filter cloth A. In this case, the exhaust gas return valve connected to the filtration chamber A through which the exhaust gas passing through the filter cloth A flows is opened. , Close the exhaust gas outlet valve. As a result, the incompletely treated exhaust gas passing through the filter cloth A is circulated, so that the exhaust gas is not discharged out of the system, and a filtration layer can be formed.

In the above embodiment, the bag type dust collector having three or four filtration chambers has been described. However, the present invention is applicable to a bag type dust collector having a smaller number of filtration chambers and a bag type dust collector having a larger number of filtration chambers. The invention applies. Further, in the above embodiment, the exhaust gas of the incomplete treatment sent by the exhaust gas return fan is supplied to the intake duct located downstream from the position where the powder of the reaction aid or the adsorbent is supplied, It may be arranged upstream of the position where the powder of the reaction aid or the adsorbent is supplied.

[0015]

According to the first aspect of the present invention, in the bag type dust collector, the exhaust side of the filtration chamber provided with the filter cloth for filtering the exhaust gas is passed through a plurality of exhaust gas return valves and an exhaust gas return fan connected thereto. Because it is connected to the common entrance side of the room,
Since the processing gas containing the unprocessed gas passing through the filtration chamber immediately after the backwashing is returned to the common exhaust gas inlet side via the exhaust gas return valve and the exhaust gas return fan, the unprocessed gas is not discharged out of the system. , Can be reliably processed inside the bag type dust collector. Further, the adsorption efficiency of harmful substances such as HCl, SOx and dioxins is high. Similarly, in the operation method of the bag type dust collector according to claims 2 and 3, after the backwash of the filter cloth in the filtration chamber, the exhaust gas from the backwashed filtration chamber is supplied to the inlet of the gas to be treated in the bag type dust collector. It has a process to return to the side,
Emission of untreated gas into the atmosphere can be prevented. This prevents the release of harmful substances to the atmosphere.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a bag type dust collector according to a first embodiment of the present invention.

FIG. 2 is an operation process diagram of the same.

FIG. 3 is a schematic explanatory view of a bag type dust collector according to a second embodiment of the present invention.

FIG. 4 is a schematic explanatory view of a bag type dust collector according to a conventional example.

FIG. 5 is an operation process diagram of the same.

[Explanation of symbols]

10: Bag type dust collector, 11 to 13: Filter cloth, 14 to 16:
Filtration chamber, 17-19: exhaust gas outlet valve, 21-23: dust discharge valve, 24: suction fan, 25: backwash fan, 26
-28: backwash valve, 29-31: exhaust gas return valve, 32: exhaust gas return fan, 33: flow meter, 34: intake duct, 3
5: rotary valve, 36: tank, 38: bag type dust collector, 40a to 40d: filter cloth, 41a to 41d: filtration chamber,
42: dust collector body, 43a to 43d: exhaust gas outlet valve, 4
4a to 44d: exhaust gas return valve, 45: suction fan, 4
6: exhaust gas return fan, 48: intake duct, 49: pulse head, 50a to 50d: diaphragm valve

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazuki Murahashi 46-59, Ohara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka New (72) Inventor Toshihiro Miyaya Tobata-ku, Kitakyushu-shi, Fukuoka 46-59 Nakahara New Nippon Steel Corporation F-term (Reference) 4D058 JA04 KB01 MA15 NA10 TA02 UA10

Claims (3)

[Claims] An exhaust side of a filtration chamber provided with a filter cloth for filtering exhaust gas is connected to an exhaust gas return valve and a common inlet of a dust collector body accommodating a plurality of said filtration chambers via an exhaust gas return fan connected thereto. And a process gas passing through the filtration chamber immediately after backwashing is returned to a common inlet side of the dust collector body via the exhaust gas return valve and the exhaust gas return fan. 2. A step of providing a filter chamber provided with a filter cloth for filtering exhaust gas, and adhering a powdery reaction aid and / or an adsorbent to the filter cloth in each of the filter chambers; A method of operating a bag type dust collector which sequentially performs a step B of backwashing a filter cloth in a chamber, wherein the backwashing of the filter cloth in the filtration chamber is followed by exhaust gas from the backwashed filtration chamber. A method of operating a bag-type dust collector, comprising: a step C for returning the gas to be treated of the dust collector to an inlet side of the dust collector to prevent discharge of untreated gas on an exhaust side. 3. The method for operating a bag type dust collector according to claim 2, wherein in the step (C), an exhaust gas outlet valve provided between an exhaust side of the filtration chamber and a suction fan is closed, and the filtration is performed. A method for operating a bag-type dust collector, comprising: opening an exhaust gas return valve provided on an exhaust side of a chamber; and performing the operation by an exhaust gas return fan provided downstream of the exhaust gas return valve.