JP4522268B2 - Exhaust gas treatment facility and purge method thereof - Google Patents

Description

  The present invention relates to an exhaust gas treatment facility and a purge method thereof, and in particular, a diesel engine (DE) exhaust gas, and a new special apparatus for ash and soot that accumulates in a DPF during DE power generation operation and causes a differential pressure increase. The present invention relates to an exhaust gas treatment facility that can be removed (discharged) without any trouble and a purge method thereof.

Diesel engines are one of those most efficient in the internal combustion engine, dioxide per constant output (CO ₂₎ emissions is low. In addition, it is economically superior because low quality fuel such as heavy oil can be used. For this reason, in recent years, vehicles and stationary power generation facilities using diesel engines with high energy utilization efficiency and low CO ₂ emissions to prevent global warming have been reviewed and tend to be used frequently.

On the other hand, diesel engines that use heavy oil or light oil as fuels have many particulate materials in which unburned hydrocarbons and soot are integrated, and it is a social problem that they are the cause of pollution. For this reason, research and development related to the removal of particulate matter (diesel particulates, hereinafter referred to as DP) has been promoted in various directions, such as diesel engine manufacturers and automobile manufacturers. DP filter that supports the oxidation catalyst and the filter in place, burns soot by converting nitrogen monoxide (NO) in the exhaust gas to nitrogen dioxide (NO ₂ ), and prevents soot clogging for a long time Studies and inventions related to (DPF) have been made (Non-patent Document 1).
Deposits such as ash and soot that accumulate in the DPF due to the long-time operation of the DE accumulate in the pores of the DPF, easily cause clogging, and increase the differential pressure. As measures against this blockage, measures are taken such that gas is blown in the direction opposite to the flow path during operation for a certain time to discharge deposits, or soot is burned by heating (Patent Document 1). .
Industrial Environmental Management Association, Environmental Management Vol.37, p441-449 JP 2002-285820 A

  In view of the above-mentioned problems of the prior art, an object of the present invention is to efficiently discharge deposits in the DPF without requiring large-scale devices and means such as backwashing, compressed air blowing, and soot heating combustion. It is an object of the present invention to provide an exhaust gas treatment facility and method capable of performing the above.

  In order to solve the above problems, the present inventors have a basic unit of a pair of a porous corrugated plate and a porous flat plate on which an exhaust gas purification catalyst is supported, so that corrugated ridge lines of the porous corrugated plate are alternately orthogonal. And forming the porous flat plate by closing one of the side surfaces orthogonal to the corrugated plate ridgeline of the molded body or two surfaces which are orthogonal to each other and adjacent to each other. A PM-containing exhaust gas purifying filter (hereinafter referred to as a cross-type DPF) in which an exhaust gas inflow path and an outflow path are respectively formed between the porous corrugated plate and the laminated body. Switching between passage and blocking of exhaust gas to means for flowing exhaust gas from the direction and to the exhaust gas flow path on the surface opposite to the surface where the exhaust gas flows, or one surface orthogonal to the surface and the direction where the exhaust gas flows Proposal of exhaust gas purification equipment with a valve It was (Japanese Patent Application No. 2004-099149). This cross type DPF has a structure in which corrugated plates 1 and flat plates 2 are alternately laminated as shown in FIG. 7, and valves 4 are provided at the outlets of the flow channels a and b as shown in FIG. By switching the valve, it passes through the DP plate and moves to the flow path b, and at that time, the DP contained in the gas is filtered and removed (filter mode). Further, the ash and soot accumulated by the DP removal operation can be blown out by closing the outlet valve of the flow path b (purge mode). The crossed DPF can discharge deposits without the need for special equipment compared to other types, but some of the ash and soot that have accumulated over a long period of operation are as shown in FIG. There is a concern that the pressure differential gradually increases when the deposit blow-out interval is shortened.

  The present invention solves the above-mentioned problems of the crossed DPF, and provides a facility and method that can more easily discharge deposits in the DPF.

The invention claimed in the present application is as follows.
(1) A molded body in which a pair of a porous corrugated sheet and a porous flat sheet is used as a basic unit, and the corrugated plate ridges of the porous corrugated sheet are alternately laminated, and the corrugated sheet of the molded body One surface of the side surface orthogonal to the ridge line or two adjacent surfaces of the orthogonal side surface are closed, and the exhaust gas inflow path and the outflow path are interposed between the porous corrugated plate and the porous corrugated plate, respectively. A filter device in which the closed surface is opened, an exhaust gas bypass passage for purging deposits deposited on the filter device with the exhaust gas, and an exhaust gas passage (filter passage) of the filter device; A plurality of exhaust gas treatment apparatuses having a switching valve for selecting any one of the bypass flow paths are provided in parallel to the exhaust gas source, and are circulated through the bypass flow path when deposits accumulated on the filter device are purged. Exhaust gas flow An exhaust gas treatment facility characterized in that a series of exhaust gas treatment devices to be purged can be selected so that a speed is higher than a flow rate of exhaust gas in a filter channel during the exhaust gas treatment.
(2) The equipment according to (1), wherein the plurality of series of bypass flow paths and filter flow paths are shared, and an open / close valve is provided in the shared flow path.
(3) The equipment according to (1), wherein the plurality of series of bypass flow paths and filter flow paths are shared, and the shared flow paths are connected via a three-way valve.
(4) In the facility described in (2) or (3), when the filter device is purged, the bypass flow paths of at least one of the two or more exhaust gas treatment apparatuses are opened, and the other series of bypass flow paths are closed. And purging the exhaust gas treatment apparatus of the above-mentioned series.

  In a normal DPF device, one DPF device is usually arranged for one DE. That is, FIG. 6 shows a normal system in which one DPF device 3 is arranged for one DE7. The DPF outlet is provided with a filter side (dust removal) line communicating with the filter device and a bypass side line for purging deposits, and a valve 4 is provided on the bypass side. 8 is a chimney. On the other hand, in the present invention, a relatively small DPF device is arranged in parallel with one or a plurality of diesel engines in a divided manner. That is, FIG. 1 shows the basic concept of the present invention, and is a system diagram of a system in which the DPF device of FIG. 6 is divided into, for example, four DPF devices 3. In FIG. 1, a plurality of DPFs are provided for one exhaust gas source (DE). However, the number of exhaust gas sources is not limited to one as shown in FIG. During operation of this system, the bypass side of all DPF devices is closed and the filter side is opened to remove PM. After a certain period of operation, two of the four DPF devices are fully closed, and the remaining two are switched to the bypass side. As a result, the flow rate on the bypass side is doubled as usual.

  2 and 3 are modifications of the system of FIG. 1, with four valves (4-a, 4-b, 4-c, 4-d) in FIG. 2 and two three-way valves 9 in FIG. By using it, operation with fewer valves becomes possible, and an economical and practical system can be obtained.

  There is no particular limitation on the ratio of the DPF device to be divided and fully closed, but if the flow rate becomes too high, the pressure loss of the entire device (system) will increase, and the supply of soot per filter unit filtration area will be a short time. Since the amount increases and the load is excessively applied, and the DPF may be damaged, it is preferable to keep the flow rate for burning off the combustion ash to a certain extent. The porous corrugated plate and the porous flat plate constituting the intersecting DPF of the present invention may carry an exhaust gas purifying catalyst such as titanium oxide or other metal oxides or platinum.

  As described above, by dividing the DPF device and increasing the flow rate of the deposit blowout, it becomes possible to discharge the ash and soot pushed into the filter pores. Stable operation is possible.

  According to the present invention, it is possible to efficiently discharge sediment without requiring new special equipment for the conventional system. In addition, as the need for large-scale diesel power generation increases, the division of the DPF device is inevitable, and the effects of the present invention are further exhibited.

  Hereinafter, the present invention will be described in detail using specific examples.

Crossed corrugated honeycomb made of nonwoven fabric of silica alumina fibers with a thickness of 0.2mm (corrugated sheet pitch 6.3mm, flat plate spacing 2.5mm, manufactured by NICHIAS, outer dimensions 300mm x 300mm x 300mm), 15% TiO ₂ sol (Ishihara Sangyo Co., Ltd.) Made by air blowing, dried at 150 ° C, impregnated with dinitrodiammine platinum solution (Pt concentration: 1.33g / L), dried again and calcined at 600 ° C, with Pt loading of 0.2g / L A DPF base material with an oxidation catalyst was prepared.

These two DPFs constitute one DPF unit, and four units (eight DPFs) are installed on the 550kWDE power generation facility as shown in Fig. 2A, and exhaust gas PM is removed at 300 ° C. did. Although the total exhaust gas flow rate from the 550 kW DE power generation facility varies depending on the configuration system and engine specifications, it was about 3000 Nm ³ / h in this example. When operating with this system on the filter side line (valves 4-b and 4-d are closed and 4-a and 4-c are open in Fig. 2A), a total of 8 DPFs are used. In this case, about 3000 Nm ³ / h of exhaust gas is treated, and this operation was carried out for 50 minutes. After that, as mode I, valves 4-a, 4-c, 4-d are closed, 4-b is opened, and for 5 minutes, then as modes II, valves 4-a, 4-b, 4-c are closed, 4 -d was opened and operated repeatedly for 5 minutes.

In modes I and II, about 3000 m ³ N / h of DE exhaust gas is introduced into the four DPFs, and the passage speed of the DPF is twice that when the filter lines (eight DPFs) are passed.
[Comparative Example 1]

  One DPF device composed of 8 DPFs prepared in the same manner as in Example 1 was installed in a 550 kW DE power generation facility as shown in FIG. 2A, and PM removal was performed at 300 ° C. In this system, when 4-b and 4-d are opened and 4-a and 4-c are closed, the exhaust gas flow rate is the same as the amount of gas flowing through the normal filter side line, and the flow rate is also equivalent. . In this system, exhaust gas was allowed to flow to the filter side for 55 minutes, and thereafter the valve was opened and gas was passed through for 5 minutes by bypass.

  In the operation of Example 1 and Comparative Example 1, the change over time in the differential pressure was compared.

  The result of Comparative Example 1 is shown in FIG. 4, and the result of Example 1 is shown in FIG. As is apparent from these figures, the differential pressure rises at 55 minutes-5 minutes in the case of Comparative Example 1, whereas when the bypass flow rate is increased (twice), PM removal is 50 minutes-bypass 5 + 5 minutes. No increase in the differential pressure over time is observed even during the operation. As is clear from this result, it can be seen that by increasing the flow rate of the bypass flow path, it is possible to discharge more of the sediment clogged in the filter during operation.

The figure which shows the system which reflected the waste gas processing equipment of this invention simply. The figure which shows the system which brought the exhaust gas treatment equipment of this invention closer to practical use. The figure which shows the system which brought the exhaust gas treatment equipment of this invention closer to practical use. The figure which shows the result of the comparative example of this invention. The figure which shows the result of the Example of this invention. The figure which shows a normal DPF system. The figure which shows the basic composition of a crossing type | mold DPF. Explanatory drawing explaining the effect | action of a crossing type | mold DPF. The schematic diagram which shows a mode that the obstruction | occlusion deposits in the pore of DPF.

Explanation of symbols

  1. Porous corrugated plate, 2. 2. porous plate; 3. Cross-type DPF device, Valve, 5. DPF element (filter), 6. 6. Deposits (ash / soot), Diesel generator, 8. 8. Chimney, Three-way valve.

Claims (4)

A molded body in which a pair of a porous corrugated sheet and a porous flat plate is used as a basic unit, and the corrugated ridgelines of the porous corrugated sheet are alternately stacked perpendicular to each other. One side surface of the side surface or two adjacent surfaces of the orthogonal side surface are closed, and an exhaust gas inflow path and an outflow path are formed between the porous corrugated plate and the porous corrugated plate through the porous flat plate, respectively. A filter device, an exhaust gas bypass channel for opening the closed surface and purging deposits deposited on the filter device with exhaust gas, an exhaust gas channel (filter channel) of the filter device, and the bypass flow A plurality of exhaust gas treatment devices having a switching valve for selecting one of the passages in parallel with the exhaust gas source, and the flow rate of the exhaust gas that is circulated through the bypass channel when purging deposits accumulated on the filter device But, An exhaust gas treatment facility characterized in that a series of exhaust gas treatment devices to be purged can be selected so as to be larger than a flow rate of exhaust gas in a filter flow path during the exhaust gas treatment. 2. The equipment according to claim 1, wherein the plurality of series of bypass flow paths and filter flow paths are shared, and an open / close valve is provided in the shared flow path. The equipment according to claim 1, wherein the plurality of series of bypass flow paths and filter flow paths are made common, and the shared flow paths are connected via a three-way valve. The facility according to claim 2 or 3, wherein when the filter device is purged, at least one of the two or more exhaust gas treatment devices of the exhaust gas treatment apparatus is opened, and the other series of bypass channels are closed and the series of the exhaust gas treatment devices are closed. A purge method for an exhaust gas treatment facility, wherein the exhaust gas treatment device is purged.

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