JPH06137132A - Gas dust removing method and device thereof - Google Patents

Abstract

PURPOSE:To prevent deterioration of dust removing performance due to difference of dust stuck quantities on filters when the filters of respective flow passages divided into a plurality of parts are regenerated in order and dust is continuously removed, in an exhaust gas dust removing device for diesel engine and the like. CONSTITUTION:A main body casing 2 is provided with inlet dumpers 1 and outlet dumpers 8. The interior is divided with heat insulated partion walls 7, and a filter 6 of ceramics porous body and an electric heater 5 removing dust are received in each gas flow passage. An anemometer 10 is arranged on the upper stream side of the inlet dumper of each gas flow passage. The signals 12 from the respective anemometers are led to a dust removing device control board 9, opening control signals 11 based on a prescribed program are transmitted from the board to the respective dumpers, and hence gas flow in the respective gas flow passages are controlled. The respective dampers are operated so that based on a prescribed filter regeneration program, the damper of the flow passage of regenerated filter in advance is opened larger, and respective gas flow are controlled to be equal, and deterioration of dust removing effect is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas dust removing method and a dust removing apparatus for removing dust from exhaust gas of a diesel engine, a boiler, a gas turbine, etc. by a filter.

[0002]

2. Description of the Related Art An example of a conventional gas dust remover is shown in FIG. In FIG. 5, the main body casing 2 of the gas dust remover
Has a gas inlet and a gas outlet, and the inside thereof is partitioned by a heat insulating partition wall 7 into a plurality of gas flow paths. An inlet damper 1 is provided at the lower end inlet of each gas flow path, and an outlet damper 8 is provided at the upper end outlet thereof.

Further, in each gas passage, there are housed a ceramic porous filter 6 for removing the gas flowing therethrough and an electric heater 5 for heating the filter 6 to which the dust is attached to remove the attached dust. Has been done. Reference numeral 4 is a power bus for energizing each heater 5. In addition, in the illustrated example, a filter is provided in each gas flow path for heat insulation and measures against distortion.
It is a double casing system in which the unit casing 3 is provided.

In the conventional apparatus having such a structure, the filter 6 disposed in each gas passage captures, for example, soot and mist in the exhaust gas of a diesel engine, and when the amount of adhered dust increases, the inlet and outlet of the gas passage After the dampers 1 and 8 are closed to suppress the gas flow therethrough, the electric heater 5 is energized to heat the filter 6 for regeneration. After the regeneration of the filter is completed, the inlet and outlet dampers 1 and 8 of the gas flow passage are opened, and similarly the filter 6 in another gas flow passage is sequentially regenerated.

FIG. 3 illustrates the above conventional dust removing method. This is the case of removing dust with a dust remover that divides the gas flow path into five parts. After completely closing the damper in the gas flow path and energizing the electric heater to regenerate the filter, fully open the damper to remove dust. This is a diagram showing a situation in which the filter is restarted and then a similar filter regeneration operation is performed for another gas flow path. As described above, conventionally, after the filter is regenerated, the damper opening 100 of the gas flow path is immediately set.
% To fully open to remove dust.

[0006]

FIG. 4 shows the dust collection characteristics of the ceramic porous filter used for gas dust removal as described above. A characteristic feature of this type of filter is that the collection efficiency is significantly changed / improved as the amount of dust adhering to the filter is increased. Further, as a general characteristic, the lower the front surface inflow velocity of the filter, the better the collection efficiency.

As described above, the gas flow path is divided into a plurality of parts,
If the damper operation is simply ON-OFF (fully open-fully closed) control when the damper is sequentially heated and regenerated by operating the damper sequentially from the filter that has been exposed to the exhaust gas for a long time, the dust collection shown in Fig. 4 is performed. As can be inferred from the collection characteristics, the filter passage just recovered from the filter just regenerated.
Has been expanded, the front inflow velocity of exhaust gas has increased,
The collection efficiency is reduced, and since the amount of dust collected by the filter is zero, the collection efficiency is reduced.

Increasing the flow rate of the exhaust gas to the filter just regenerated brings about a decrease in the flow rate to the filter having a high collection efficiency (filter with a large amount of collected dust), and in this respect also, the dust collection efficiency of the entire dust remover Will be a factor to reduce. As described above, it is an object of the present invention to provide a gas dust removing method and a dust removing apparatus therefor that do not cause a reduction in collection efficiency as seen in the prior art.

[0009]

As described above, a ceramic foam filter has a lower collection efficiency when the amount of collected dust is smaller, and a filter with a larger collection amount under the same differential pressure across the filter. Compared with, the amount of exhaust gas passing through is increased, which also has the property of reducing the collection efficiency.

Therefore, the present invention is to solve the above-mentioned problems in the gas dust removing method in which the filters are divided into a plurality of gas passages each having a damper and arranged in each of the gas flow passages to sequentially regenerate the filters and remove the dust. A method of removing dust by opening the damper as far as the damper of the gas passage is arranged in the order of filter regeneration in the gas passage is adopted.

That is, for a freshly regenerated filter and a filter with a low collection efficiency, which has a small collection amount,
As a method of suppressing the increase in exhaust gas inflow due to the low pressure loss property, the opening degree of the damper at each flow path inlet / outlet is suppressed. As a result, it is possible to prevent the dust collection efficiency of the entire dust removal device (the entire operating flow path) from decreasing, and to maintain a high collection efficiency.

Further, in order to solve the above-mentioned problems, the present invention uses a filter arranged in each of the gas passages, each of which is divided into a plurality of parts and has a damper, to successively regenerate the filter and remove the dust. In the above method, a method of removing dust by controlling the opening and closing of the damper so that the gas flow rates in the gas flow paths are approximately equal is also adopted.

For example, the opening / closing damper opening of the flow path having a filter of the maximum dust collection amount in the gas flow path (filter having the longest exhaust gas exposure time) is set to 100%, and conversely, the flow having a filter of the minimum dust collection quantity. The inlet / outlet damper of the passage is maximally throttled, and the total equivalent pressure loss of the filter and the inlet / outlet damper is equalized, that is, the exhaust gas flow rate is equalized.

Further, the opening and closing damper openings of the flow path having the filter having the remaining amount of collected dust are also adjusted so that the total equivalent pressure loss becomes equal. Furthermore, if there is a margin in pressure loss, the exhaust gas flow rate of the gas flow path with a filter with a small amount of dust collection will be set to be smaller than the exhaust gas flow rate of the filter flow path with a large amount of dust collection. Adjust the opening / closing of the door damper.

Further, the present invention is an apparatus for carrying out the above-mentioned gas dust removing method, wherein a plurality of gas passages are divided, a damper and a filter arranged in each of the gas passages, and a heater for regeneration. In a gas dust removing device having a gas flow rate detecting device for detecting a gas flow rate of each gas flow path, and a damper opening control device for narrowing down a damper of a gas flow path having a large gas flow rate detected by the detection device To adopt.

In the dust remover such as the present invention, the flow passage is divided into a plurality of portions in order to enable continuous operation. However, since the flow passages are branched or gathered at the entrance and exit portions of the dust remover, the flow passages are divided. It is impossible to detect the gas flow rate in each flow path by the pressure difference between the inlet and outlet of the.

Therefore, here, it is impossible to detect the gas flow rate precisely, but in order to control the opening degree of each channel inlet / outlet damper, the heat ray wind velocity is applied to the cross section of each channel, for example, several points in front of the inlet damper. Install a meter (or equivalent) and detect the flow rate imbalance between each flow path from these average values.
Controls the inlet / outlet damper of the corresponding flow path.

[0018]

According to the present invention, in the dust removing method in which the gas passages are divided into a plurality of portions and the filters in the respective gas passages are sequentially regenerated, as described above, the dampers in the respective gas passages are arranged in the regenerating order of the filters in the gas passages. As the damper of the gas passage is opened more to remove dust, the damper of the most inefficient freshly regenerated filter is throttled to the maximum and conversely the filter passage with the longest exposure time is used. By controlling the opening of the damper to 100% and the opening of the damper of the flow path of the filter in an intermediate state to an intermediate value between them, the dust collecting efficiency of the entire dust removing device can be maintained high. .

Further, according to the present invention, the dampers arranged in the gas flow passages are controlled to open and close so that the gas flow rates in the respective gas flow passages are approximately the same, and dust is removed. It is possible to prevent the flow amount from being unbalanced due to the difference in the collection amount of each filter, and it is possible to maintain a high dust collection efficiency. When there is a margin in the overall pressure loss, it is possible to select a control such that the gas flow rate of the freshly regenerated passage is further reduced as described above.

Further, the apparatus according to the present invention is a gas flow rate detecting device for detecting the gas flow rate of each gas flow passage, and a damper opening control for narrowing down the damper of the gas flow passage having a large gas flow amount detected by the detection device. Since it has a device, it is possible to efficiently carry out the above-mentioned gas dust removal method, and it is also easy to operate it automatically.

[0021]

Embodiments of the present invention and an apparatus according to the present invention will be specifically described below based on the embodiment shown in FIG. In FIG. 1, the same parts as those of the conventional apparatus shown in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted. Figure 1
As shown in FIG. 5, a main body casing 2 having a larger flow passage than that of the gas inlet duct is provided, and like the one shown in FIG.

As in the case of FIG. 5, an inlet damper 1, an outlet damper 8, an electric heater 5 and a filter 6 made of ceramics foam are provided in a heat insulating filter unit casing 3 for each flow path. .
The filter unit casing 3 is the main casing 2
And are fixed only at two places at the lower end, and are free to be thermally deformed upward. On the upstream side of the inlet damper 1 of each gas flow path,
An anemometer 10 is provided for controlling the opening degree of the inlet damper 1 and the outlet damper 8 of each gas flow path.

The flow velocity signal 12 from each anemometer 10 is guided to the dust remover control panel 9, and the control panel 9 transmits the opening signal 11 to each damper based on the preset filter regeneration program. To control the gas flow rate in the gas channel, or to make the gas flow velocity in each gas channel equal,
That is, the flow rate of each gas is controlled to be equal in each flow path.

In the gas dust remover having the above-mentioned structure, the exhaust gas passes through the filter 6 in the flow path where the damper is open, and the dust in the gas is collected by the filter 6 during that time. At this time, the heater 5 in the gas flow path is O
Set to the FF state. In the flow path where the damper is fully closed,
When the heater 5 is turned on, the combustible dust is heated and oxidized from the surface of the filter 6 mainly by the radiant energy, and the filter 6 is regenerated. In addition, the upper part of the filter 6 and the thickness direction are also sequentially heated and regenerated by the passage of the heated damper leak exhaust gas.

In the present invention, the method of removing the dust in the filter by opening the damper of the gas passage divided into a plurality as much as the damper of the previous gas passage in the order of regeneration of the filter in the gas passage is adopted. The uneven flow of gas due to the difference in the adhered amount is prevented. For example, the damper in the flow path of the freshest regenerated filter with the least efficiency is maximally closed, while the damper in the flow path of the filter with the longest exposure time has an opening of 10 degrees.
By controlling the opening degree of the damper of the flow path of the filter in the intermediate state to 0% to the intermediate value between them, the dust collecting efficiency of the entire dust removing device can be maintained high.

FIG. 2 schematically shows a method of controlling the damper of the gas passage according to the present invention. FIG. 2 shows a situation in which the narrowing down of the damper in the gas passage after the filter regeneration is gradually opened. The damper control according to the present invention enables continuous operation in which the dust collection, heating and regeneration of the filter are repeated while keeping the collection efficiency high.

When the dust concentration or the pressure drop has a margin, heating of the filter is aimed at further improving the collection efficiency.
Aim to further improve the collection efficiency by extending the set cycle such as lengthening the regeneration cycle (exhaust gas exposure time) and controlling the narrowing of the inlet / outlet damper of the flow path after filter heating / regeneration so that it is below the same flow rate. It is also possible to select. It goes without saying that the above operation, that is, the control operation of the damper and the heater, is performed from the dust remover control panel 9 and the automatic operation / automatic monitoring can be performed.

[0028]

As described above in detail, in the gas dust removing method according to the present invention, when the filters of the gas passages partitioned into a plurality of pieces are sequentially regenerated, the dampers of the gas passages are replaced by the gas passages. The method of opening the filter in the order in which the filter is regenerated in the order of opening is larger than that of the previous one in the gas passage, or the method of controlling the opening and closing of each damper so that the gas flow rate in each of the gas passages is approximately the same is adopted. The dust collection efficiency can be increased without the drawback of the filter characteristics of this type of dust remover that a large amount of gas flows to the filter with low collection efficiency, resulting in a highly efficient exhaust gas dust removal method. It becomes possible to provide.

Further, the gas dust removing apparatus according to the present invention controls the opening of the gas flow rate detecting device for detecting the gas flow rate of each gas flow passage and the damper of the gas flow passage having a large gas flow rate detected by the detection device. Since the device is provided with a device, it is possible to prevent a large amount of gas from flowing through the filter having a low collection efficiency immediately after the regeneration, and to obtain a device having a high collection efficiency.

As a result, fine particles such as diesel exhaust gas (soot: up to 1
μ), oil mist (˜10 μ), etc. can be efficiently collected, and a dust remover capable of performing stable and continuous operation is put into practical use.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of a dust remover body according to a first embodiment of the present invention in a broken manner.

FIG. 2 is a diagram showing a control situation of a damper in each gas flow path according to the present invention.

FIG. 3 is a diagram similar to FIG. 2 showing a control state of a damper in each gas flow path in a conventional dust removing method.

FIG. 4 is a graph showing the dust collection characteristics of ceramic foam.

FIG. 5 is a perspective view showing a conventional gas dust remover with a part broken away.

[Explanation of symbols]

 1 Inlet Damper 2 Main Body Casing 3 Filter Unit Casing 4 Power Bus 5 Electric Heater 6 Ceramic Foam Filter 7 Adiabatic Partition 8 Outlet Damper 9 Dust Removal Control Panel 10 Anemometer 11 Damper Opening Signal 12 Velocity Signal

Claims (3)

[Claims] 1. A gas dedusting method in which a plurality of partitions are provided in each of the gas passages, each of which has a damper, and the filters are sequentially regenerated to remove dust. A method for removing gas dust, characterized in that the damper in the gas passage is opened as much as possible in order of filter regeneration to remove dust. 2. A gas dust removing method in which a plurality of partitions are provided in each of the gas flow paths each having a damper and the filters are sequentially regenerated to remove dust. A gas dedusting method characterized in that the gas flow rate in the gas flow path is made substantially equal to remove dust. 3. A gas flow path divided into a plurality of parts, a damper and a filter and a regeneration heater disposed in each of the gas flow paths, a gas flow rate detection device for detecting the gas flow rate of each gas flow path, A gas dust remover comprising: a damper opening control device that narrows down a damper of a gas flow path having a large gas flow rate detected by the detection device.