JP5928002B2 - High speed exhaust gas treatment filter and high speed exhaust gas dust remover - Google Patents

Description

  The present invention relates to a high-speed exhaust gas treatment filter and a high-speed exhaust gas dust removal device that are preferably used for high-speed exhaust gas dust removal.

  There are many industrial processes that generate exhaust gas, such as combustion and cooling of high-temperature substances. The exhaust gas generated in these processes often includes dust such as soot. Therefore, exhaust gas dust removing means is required. For example, a metal mesh filter is widely used as the dust removing means. However, a metal mesh filter is likely to be clogged with dust and deteriorated by corrosion.

  Therefore, a dust removing device using a ceramic filter or a mechanical cyclone that is less likely to be clogged or corroded has been developed. For example, Patent Document 1 below describes a technique for preventing clogging by removing dust from combustion gas using a ceramic filter and providing a cleaning means for the ceramic filter. Patent Document 2 describes a technique that facilitates cleaning of a ceramic filter by using a ceramic filter and a mechanical cyclone in combination.

Japanese Patent Laid-Open No. 10-318 JP-A-10-33927

  However, ceramic filters and mechanical cyclones such as those described in Patent Documents 1 and 2 have a large resistance to dust exhaust, and therefore have a large pressure loss due to dust removal. In the case of high-speed exhaust gas, that is, exhaust gas having a relatively high flow rate, the pressure loss is further increased. Therefore, the conventional dust removing means as described above is not easy to apply to high-speed exhaust gas.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to effectively remove dust contained in high-speed exhaust gas with less pressure loss. It is an object of the present invention to provide a new and improved high-speed exhaust gas treatment filter and high-speed exhaust gas dust remover.

  In order to solve the above-described problem, according to an aspect of the present invention, a plurality of cell passages through which high-speed exhaust gas passes are provided. A filter for high-speed exhaust gas treatment is provided, which is characterized by collecting collected dust.

  According to such a configuration, since the flow path of the exhaust gas is ensured as the cell passage, it is possible to suppress resistance when the exhaust gas is passed through the filter. Therefore, even when the exhaust gas is at a high speed, pressure loss caused by dust removal can be suppressed. Further, by spraying the liquid on the inner wall surface of the cell passage, dust can be efficiently collected using turbulent flow and inertial collision.

  In the high-speed exhaust gas treatment filter, the plurality of cell passages may have a honeycomb structure. Further, the cross-sectional shape of each cell passage may be a hexagon. Thus, by making the filter into a honeycomb structure (a structure in which the cell passage is plane-filled in the cross section), it is possible to secure a wider cell passage, that is, an exhaust gas passage, and further suppress resistance. .

  In order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a high-speed exhaust gas dust removing device comprising the above-described high-speed exhaust gas treatment filter and a spraying means for spraying liquid. The In this high-speed exhaust gas dust remover, the exhaust gas is vented upward, for example. At this time, when the liquid droplet dropping speed is smaller than the exhaust gas flow velocity, the spraying means may be installed below the high-speed exhaust gas treatment filter. Further, when the liquid droplet dropping speed is larger than the flow rate of the exhaust gas, the spraying means may be installed above the high-speed exhaust gas treatment filter. In this way, by adjusting the arrangement of the filter and spraying means according to the exhaust gas flow velocity and droplet particle size, liquid can be reliably sprayed on the inner wall surface of the cell passage, and dust can be collected efficiently. can do.

  As described above, according to the present invention, dust contained in high-speed exhaust gas can be effectively removed with less pressure loss.

1 is a perspective view of a honeycomb filter according to an embodiment of the present invention. It is an AA arrow directional view of the honeycomb filter shown in FIG. It is a figure which shows the structure of the exhaust gas dust removal apparatus which concerns on one Embodiment of this invention.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(1. Filter configuration)
First, the structure of an exhaust gas treatment filter according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of a honeycomb filter according to an embodiment of the present invention. FIG. 2 is an AA arrow view of the honeycomb filter shown in FIG.

  Referring to FIGS. 1 and 2, the honeycomb filter 1 is formed with a large number of cell passages 2 through which exhaust gas passes. The cell passage 2 is a passage defined by a cell partition wall 3 formed of a plate material such as a steel plate. The cell passage 2 has a hexagonal cross-sectional shape and extends linearly in the exhaust gas aeration direction. Note that the number of the cell passages 2 may be larger or smaller than the illustrated example depending on, for example, the cross-sectional area of the duct in which the honeycomb filter 1 is disposed.

  Here, the cell passage 2 has a honeycomb structure. That is, when viewed in the cross-sectional direction (AA arrow direction) of the honeycomb filter 1, the cross-section of the cell passage 2 is plane-filled. Thus, if the cell passage 2 which is a flow path of the exhaust gas is widely secured, the resistance can be further suppressed.

  The cross-sectional shape of the cell passage 2 forming the honeycomb structure is not limited to the hexagon as shown in the illustrated example, and may be another shape capable of plane filling, such as a triangle or a quadrangle. In addition, when a cross-sectional shape is a hexagon, there exists an advantage that the honey-comb filter 1 can be manufactured easily by using a folded-plate material for the cell partition 3, for example.

  As is clear from the above, in this specification, the term “honeycomb filter” means a filter having a structure in which the cell passages are flat-filled in the cross section, and the cross-sectional shape of the cell passages is not necessarily hexagonal. Does not mean that there is.

  On the other hand, water is sprayed on the inner wall surface 2 i of the cell passage 2 by a watering nozzle described later. That is, when exhaust gas is ventilated through the honeycomb filter 1, the inner wall surface 2i is in a state of being wet with water. Therefore, when dust contained in the exhaust gas collides with the inner wall surface 2i due to turbulent flow or inertial collision, the dust is collected on the inner wall surface 2i. In this way, the honeycomb filter 1 removes the exhaust gas.

  In the honeycomb filter 1, dust is collected by the inner wall surface 2 i as described above, so that there is almost no possibility of clogging. Therefore, corrosion deterioration due to the corrosive substance in the exhaust gas caused by clogging is less likely to occur. Therefore, the honeycomb filter 1 can be used for a longer period of time than, for example, a conventionally used metal mesh filter. In order to further improve the durability of the honeycomb filter 1, it is desirable that the cell partition walls 3 be formed of a corrosion-resistant metal plate such as a galvanized steel plate or a stainless steel plate.

  As described above, in the honeycomb filter 1, the flow path of the exhaust gas is ensured as the cell passage 2, and the cell passage 2 extends linearly, so that the resistance when the exhaust gas is vented to the honeycomb filter 1 is small. . Therefore, even when the exhaust gas is at a high speed, the pressure loss caused by installing the honeycomb filter 1 is small. Therefore, using the honeycomb filter 1 makes it easy to remove dust while ventilating a large amount of exhaust gas.

  In the present embodiment, the flow rate of the exhaust gas is about 5 m / s to 15 m / s. In this case, the dimensions of the cell passage 2 shown in FIG. 2 are preferably about 50 mm to 150 mm for both W and D, for example. This is because when W and D are less than 50 mm, it is difficult to make the water spray reach the inner wall surface 2 i, and when W and D exceed 150 mm, dust that collides with the inner wall surface 2 i is reduced.

  In this case, the length L of the honeycomb filter 1 is desirably about 0.5 m to 1.5 m. This length L may be set, for example, with reference to the time required for exhaust gas to pass through the cell passage 2 being about 0.1 seconds.

  Even when the flow rate of the exhaust gas is not in the range of 5 m / s to 15 m / s, it is possible to remove the exhaust gas using the honeycomb filter 1. However, when the flow velocity is less than 5 m / s, for example, pressure loss may not be a problem even with other types of filters. Therefore, the advantage of using the honeycomb filter 1 is superior to that when the flow velocity is 5 m / s or more. Become smaller. Moreover, when the flow velocity exceeds 15 m / s, the dust collected by colliding with the inner wall surface 2 i is less than that when the flow velocity is 15 m / s or less.

(2. Configuration of exhaust gas dust remover)
Next, with reference to FIG. 3, the structure of the exhaust gas dust removal apparatus which concerns on one Embodiment of this invention is demonstrated. FIG. 3 is a diagram showing a configuration of an exhaust gas dust removing apparatus according to an embodiment of the present invention.

  As shown in FIG. 3, the honeycomb filter 1 for high-speed exhaust gas treatment described above may be provided as an exhaust gas dust removing device 5 in combination with a watering nozzle 4 which is a spraying means for spraying water on the inner wall surface 2i. Good. In the illustrated example, the exhaust gas dust remover 5 is installed in a substantially vertical duct D through which exhaust gas is vented upward.

In this case, the installation position of the sprinkler nozzle 4 varies depending on the magnitude relationship between the flow rate V _G of the falling velocity V _W and the exhaust gas of water droplets sprayed from the water spray nozzle 4. The drop speed _VW of the water droplet is a terminal velocity when it is assumed that the water droplet falls in the stationary exhaust gas, and increases as the particle size of the water droplet increases. If it is V W _{<V G,} water droplets after injection to rise, it is established (a), the water spray nozzle 4a is the lower honeycomb filter 1. On the other hand, if V _W> V _G, since the water droplet after jetting drops are placed as shown, watering nozzles 4b is above the honeycomb filter 1 (b). Incidentally, the flow rate of the exhaust gas varies, if such magnitude relation between V _W and V _G is changed, the watering nozzle 4a and watering nozzle 4b may be both disposed.

  In any case, the arrangement of the watering nozzle 4 is determined so that the water sprayed over the entire inner wall surface 2i is distributed based on the spray angle of the watering nozzle 4 and the distance from the watering nozzle 4 to the honeycomb filter 1. Is done. As illustrated, when the honeycomb filter 1 has a large cross-sectional area, a plurality of watering nozzles 4 may be arranged along the honeycomb filter 1. In addition, the liquid sprayed from the watering nozzle 4 does not necessarily need to be water, and may be other non-volatile liquid, for example.

  The exhaust gas dust removing device 5 is not necessarily installed in the duct D through which the exhaust gas is vented upward as illustrated. For example, the exhaust gas may be vented downward. In this case, the watering nozzle 4 is installed above the honeycomb filter 1 regardless of the flow rate of the exhaust gas. Further, the exhaust gas dust removing device 5 may be installed in a duct in a horizontal direction or an oblique direction.

  Next, examples of the present invention will be described. In this example, as shown in Table 1 below, an example in which a honeycomb filter similar to the honeycomb filter 1 according to the above embodiment is installed, a comparative example in which no filter is installed, and a metal mesh filter are provided. About the comparative example installed, the test which measures the dust collection rate and a pressure loss was implemented by changing the flow velocity of the exhaust gas, the amount of sprinkling, and the length of the honeycomb filter.

In the above test, as the dust, a mixture of 1 type and 2 types (silica sand) of the test powder 1 defined in JIS Z8901 at a ratio of 1: 1 was used. The main particle size of such dust is 30 μm to 200 μm, and the true density is 2.6 g / cm ³ . In the test, this dust was supplied into an air stream at a dust generation concentration of 0.43 g / m ³ , and this air stream was vented upward into a 60 cm square rectangular duct. The flow velocity of the air flow was varied in three stages of 5 m / s, 8 m / s, and 10 m / s.

  Further, a honeycomb filter having a cell passage dimension of W = 115 mm and D = 70 mm shown in FIG. 2 was installed. In addition, the folded plate of the galvanized steel plate was used for the cell partition. The length L of the honeycomb filter was varied in two stages of 0.5 m and 1.0 m.

Furthermore, in the test, in both the example and the comparative example, a watering nozzle was installed below the filter installation part, and water was sprayed toward the filter installation part. When the filter is installed, the distance between the filter and the watering nozzle is 115 mm, and the water pressure of the watering nozzle is 0.3 kN / cm ² . The dust collection rate in each example and comparative example was calculated by collecting the dust that flowed down with the water sprinkled by the watering nozzle, and determining the mass ratio of the collected dust and the supplied dust.

  In addition, the watering amount of the watering nozzle varies in two stages of 12.89 l / min and 6.67 l / min. When the water spray amount is 12.89 l / min, the spray angle of the water spray nozzle is 70 °, the average particle diameter of the water droplets is 260 μm, and the average drop speed of the water droplets is 2 m / s. When the water spray amount is 6.67 l / min, the spray angle of the water spray nozzle is 80 °, the average particle diameter of the water droplets is 220 μm, and the average drop speed of the water droplets is 1.4 m / s.

(Comparison of filter types)
The above results will be examined below. First, the dust collection rate and pressure loss depending on the type of filter when the airflow velocity is 5 m / s (Comparative Example 3, Example 2) and 10 m / s (Comparative Example 4, Example 7). Consider changes in In the above test, even when the filter is not installed (Comparative Examples 1 and 2), the dust collected on the wall surface of the duct is collected, so the dust collection rate does not become 0%.

  When the flow rate is 5 m / s, the dust collection rate is substantially the same between Example 2 (honeycomb filter) and Comparative Example 3 (mesh filter) (86.9% in Example 2, Comparative Example 3). (85.2%). On the other hand, the pressure loss in Example 2 is slightly less than that in Comparative Example 3 (20.5 kPa in Example 2 and 23.5 kPa in Comparative Example 3).

  When the flow rate is 10 m / s, the dust collection rate of Example 7 (honeycomb filter) is higher than that of Comparative Example 4 (mesh filter) (68.5% in Example 7 and 55% in Comparative Example 4). ). In addition, the pressure loss in Example 7 is significantly less than that in Comparative Example 4 (37.2 kPa in Example 7 and 53.9 kPa in Comparative Example 4).

  From the above results, it was proved that the honeycomb filter according to the embodiment of the present invention has an effect of suppressing pressure loss to be less than that of the mesh filter while realizing a dust collection rate higher than that of the mesh filter. It was also demonstrated that the above effects become more pronounced when the flow rate is higher.

(Effect of honeycomb filter length)
Next, the influence of the length L of the honeycomb filter 1 will be examined. In the above test, L = 0.5 m and L = 1.0 m when the flow rate is 5 m / s (Examples 1 and 2) and when the flow rate is 10 m / s (Examples 5 and 7). Measurements were performed in two ways.

  When the flow rate is 5 m / s, Example 2 (L = 1.0 m) has a higher dust collection rate than Example 1 (L = 0.5 m) (86.9% in Example 2, In Example 1, 55.3%). On the other hand, there is almost no difference in pressure loss between Example 2 and Example 1 (20.5 kPa for both Example 1 and Example 2).

  When the flow rate is 10 m / s, the dust collection rate in Example 7 (L = 1.0 m) is higher than that in Example 5 (L = 0.5 m) (68.5% in Example 7, In Example 5, 54.1%). On the other hand, the pressure loss in Example 7 is larger than that in Example 5, but the difference is smaller than the difference in dust collection rate (37.2 kPa in Example 7, 35. 3 kPa).

  From the above results, it was found that the length of the honeycomb filter according to the embodiment of the present invention greatly affects the dust collection rate but does not significantly affect the pressure loss. Therefore, for example, within the predetermined length range as described in the embodiment, it is possible to improve the dust collection rate while suppressing the increase in pressure loss by adjusting the length of the honeycomb filter. It can be said that there is.

(Effect of water spray)
Next, the effect of water spray will be examined. In the honeycomb filter test, the amount of water sprayed was 6.67 l / min and 12.89 l when the flow rate was 8 m / s (Examples 3 and 4) and when the flow rate was 10 m / s (Examples 6 and 7). Measurement was carried out in two ways / min. On the other hand, in the test of the mesh filter, the watering amount was measured at 12.89 l / min.

  In the above test, when the amount of water sprayed by the honeycomb filter was 6.67 l / min (Example 6) and when the amount of water sprayed by the mesh filter was 12.89 l / min (Comparative Example 4), In this case, it is understood that the dust collection rate is improved as compared with the case of the mesh filter even though the amount of water spray is about half that of the mesh filter (63.8% in Example 6, comparative example). 4 is 55%).

  On the other hand, when the cases where the water spray amount is different between the honeycomb filters are compared, it is found that the increase in the water spray amount does not necessarily lead to a marked improvement in the dust collection rate in the honeycomb filter. Specifically, when the flow rate is 8 m / s, the dust collection rate is higher in Example 4 (watering amount 12.89 l / min) than in Example 3 (watering amount 6.67 l / min). (68.7% in Example 4 and 65.2% in Example 3), and the pressure loss is large (31.3 kPa in Example 4 and 26.4 kPa in Example 3). However, the difference in dust collection rate and pressure loss here is small compared to the difference between the other examples.

  Further, when the flow rate is 10 m / s, the dust collection rate is higher in Example 7 (watering amount 12.89 l / min) and in Example 6 (watering amount 6.67 l / min) ( Example 7 is 68.5%, Example 6 is 63.8%), and pressure loss is also large (Example 7 is 37.2 kPa, Example 6 is 36.2 kPa). However, the difference in dust collection rate and pressure loss here is also small compared to the difference between the other examples.

  From the above results, in the honeycomb filter according to the embodiment of the present invention, a sufficient dust removal effect is exhibited with a smaller amount of water than the mesh filter, and if the water is sprayed to the extent that the entire inner wall surface is spread, it is more than that. It turned out that watering is not always necessary.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Honeycomb filter 2 Cell passage 2i Inner wall surface 3 Cell partition 4a, 4b Sprinkling nozzle 5 Exhaust gas dust removal apparatus

Claims (5)

A plurality of cell channels which exhaust gas passes,
The flow rate of the exhaust gas in each cell passage is 5 m / s to 15 m / s,
The cross-sectional dimension of each cell passage is 50 mm to 150 mm,
The plurality of cell passages have a honeycomb structure;
A high-speed exhaust gas treatment filter, wherein a liquid is sprayed on an inner wall surface of each cell passage, and dust contained in the exhaust gas is collected by the liquid. The high-speed exhaust gas treatment filter according to claim 1 , wherein a cross-sectional shape of each cell passage is a hexagon. The high-speed exhaust gas treatment filter according to claim 1 or 2 ,
A high-speed exhaust gas dust removing device comprising: a spraying means for spraying the liquid. The exhaust gas is vented upward,
4. The high-speed exhaust gas dust removing device according to claim 3 , wherein when the liquid droplet dropping speed is smaller than the flow rate of the exhaust gas, the spraying unit is installed below the high-speed exhaust gas treatment filter. . The exhaust gas is vented upward,
If droplets falling velocity of the liquid is greater than the flow rate of the exhaust gas, characterized in that the spraying means is disposed above the filter for high-speed exhaust gas treatment, high-speed exhaust gas according to claim 3 or 4 Dust removal device.

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