JP5863087B2 - Exhaust gas treatment equipment for large displacement diesel engines using low quality fuels below heavy oil - Google Patents

Description

The present invention removes particulate matter (Particulate Matter: hereinafter referred to as “PM”) and harmful gas mainly contained in exhaust gas of a diesel engine and removes and purifies, particularly for ships, power generation, industrial use, etc. The present invention relates to exhaust gas processing technology for large-displacement diesel engines that use low-quality fuel below heavy oil, and more specifically, corona discharge in large-displacement diesel engines that use low-quality fuel below heavy oil that discharges high-temperature exhaust gas. The present invention relates to a used exhaust gas treatment device.

  Diesel engines are widely used as power sources for various ships, generators, large construction machines, and various automobiles, but as is well known, PM contained in exhaust gas discharged from diesel engines is air pollution. In addition to toxic substances, it is a substance that is extremely harmful to the human body, so purification of the exhaust gas is extremely important. For this reason, many proposals have already been made, such as improvements in the combustion system of diesel engines, the use of various exhaust gas filters, and methods of electrical treatment using corona discharge, some of which have been put into practical use. .

  Here, components of PM (particulate matter) in exhaust gas of a diesel engine are organic solvent soluble (SOF: Soluble Organic Fractions, hereinafter referred to as “SOF”) and organic solvent insoluble (ISF: Insoluble Organic). Fractions (hereinafter referred to as “ISF”), of which SOF is mainly composed of unburned fuel and lubricating oil, and harmful substances such as polycyclic aromatics that have a carcinogenic effect. included. On the other hand, the ISF component is mainly composed of carbon (soot) and sulfate (sulfate) components having low electrical resistivity. The SOF component and the ISF component are affected as much as possible because of their effects on the human body and the environment. Less exhaust gas is desired. In particular, it is also said that the degree of adverse effects of PM in a living body is particularly problematic when the particle diameter is nm.

  For example, methods and apparatuses described below (Patent Documents 1 to 5) have been proposed as a method of performing electrical treatment using corona discharge.

  That is, in Patent Document 1, as schematically shown in FIG. 12, a discharge charging unit 22 including a corona discharge unit 22-1 and a charging unit 22-2 is connected to the exhaust gas passage 21 to corona discharge. The charged electrons 29 are charged to the PM 28 mainly composed of carbon in the exhaust gas G 1, and the charged PM 28 is collected by the collection plate 23 disposed in the exhaust gas passage 21. The electrode needle 24 has a short length in the flow direction of the exhaust gas flow, and the collecting plate 23 is arranged in a direction perpendicular to the flow direction of the exhaust gas flow. Methods and apparatus have been proposed. In the figure, 25 is a seal gas pipe, 26 is a high voltage power supply device, and 27 is an exhaust gas induction pipe.

  Further, in Patent Document 2, as schematically shown in FIG. 13, a needle electrode 31 for charging a PM 33 in exhaust gas by causing a corona discharge 35 around the needle tip 31-1 and a charged PM 33 are disclosed. Exhaust gas trapping of a diesel engine provided with a collecting electrode 32 for collecting the gas and a high-voltage DC power source 34 for applying a predetermined DC high voltage between the needle electrode 31 and the collecting electrode 32 A collecting device has been proposed. In the figure, 36 is a deflection electrode.

  Further, in Patent Document 3, as schematically shown in FIG. 14, a fixed cylindrical body 41 that constitutes one of a collection electrode pair for collecting PM provided in an exhaust path, and a center of the fixed cylindrical body 41. The electrode rod 42 extending in the axial direction at the portion and constituting the other of the collection electrode pair, and an electrostatic field is formed between the collection electrode pair to accumulate PM in the exhaust gas on the inner surface of the fixed cylindrical body 41. Exhaust gas purification provided with a high voltage power supply unit 43 and a scraping unit 44 that rotates relative to the fixed cylindrical body along the inner surface of the fixed cylindrical body 41 to scrape PM accumulated on the inner surface of the fixed cylindrical body. A device has been proposed. In the figure, 45 is an exhaust pipe, and 46 is a rotating cylindrical part.

On the other hand, Patent Document 4 discloses a discharge electrode for charging PM contained in exhaust gas of a diesel engine, an electric dust collection means having a dust collection electrode for collecting charged PM, and a dust collection electrode. Engine exhaust gas purification device provided with means for separating the PM accumulated from the dust collecting electrode and a cyclone-type separation collecting means for separating and collecting the PM peeled from the dust collecting electrode has been proposed .
As shown in FIG. 15, this apparatus is configured to process exhaust gas while flowing in the lateral direction, and serves as an electric dust collector 51 for collecting PM and a separate collector. The electrostatic dust collecting portion 51 is a collection of a cylindrical metal body 57 attached to the inner peripheral surface of the cylindrical housing 56 and an uneven portion 58 formed on the inner peripheral surface of the cylindrical metal body. The dust electrode 54, a main electrode 59 extending along the axis of the dust collection electrode 54, and a group of radially projecting electrode needles 60 disposed at predetermined intervals in the longitudinal direction of the main electrode 59. The cyclone 52 is configured at a downstream side of the guide vane 61 that converts the flow of the gas flow 53 that has passed through the electrostatic precipitator 51 into a swirl flow, and the cyclone is disposed downstream of the cyclone 52. The gas inside An exhaust pipe 62 of the eye, a hopper 63 for collecting PM, which is centrifuged is provided. A separation mechanism 64 separates the PM collected and collected by the dust collection electrode 54 from the dust collection electrode 54, and includes, for example, an eccentric motor 65 that generates vibration due to eccentricity. Reference numeral 66 denotes an extraction pipe for returning the exhaust gas in the exhaust pipe 62 to the upper space of the hopper 63.
That is, in the exhaust gas purification apparatus having the above-described configuration, PM in the exhaust gas flowing into the electric dust collector 51 is charged by the discharge between the dust collection electrode 54 and the discharge electrode 55 and captured by the dust collection electrode 54 by the Coulomb force. The collected and collected PM flows into the guide vane 61 together with the gas flow, and the PM is centrifuged by the cyclone 52 formed at the downstream side of the guide vane 61. The centrifuged PM is put into the hopper 63. On the other hand, the exhaust gas that has fallen and was collected and purified is discharged to the outside through the exhaust pipe 62.

  Further, Patent Document 5 includes a charge aggregation portion that collects and aggregates the components to be collected in the exhaust gas of a diesel engine mounted on an automobile by corona discharge, and a filter portion that collects the aggregated components. As shown in FIGS. 16 and 17, the gas aggregating unit 70 is arranged on the upstream side and the filter unit 80 is arranged on the downstream side as shown in FIGS. The dust collecting electrode of the low voltage electrode is formed by the conductive cylindrical body 71f formed by the bodies 71, 71a, etc., and disposed in the vicinity of the surface of the gas passage wall, and is disposed inside these cylindrical bodies. A corona electrode is formed by a high-voltage electrode of a linear body, and a cylindrical body of the gas passage wall is formed as a gas cooling portion that cools the gas by natural convection and heat radiation, and further, the gas passage wall Of the cylindrical body or the conductive cylindrical body To gas flow through the vicinity of the back surface, the means for accelerating turbulence 71e to promote turbulence, the gas processing devices constituting provided on the surface or near the surface of the tubular body is shown. In the figure, 71c is a gas inlet chamber, 71b is a corona electrode, and 71d is a gas outlet chamber.

WO2006 / 064805B JP-A-9-112246 Japanese Patent Laid-Open No. 6-173637 JP 2006-136766 A Japanese Patent No. 4529013

However, the above-described conventional diesel engine exhaust gas purification apparatus has the following drawbacks.
That is, in the electric processing method and apparatus for exhaust gas of a diesel engine described in Patent Document 1, the electrode needle 24 in the discharge charging unit 22 is short in the flow direction of the exhaust gas flow, and the collection plate 23 is exhausted. It is arranged in a direction perpendicular to the flow direction of the gas flow, and the exhaust gas flow is in direct contact with the collection plate 23, so that the flow resistance (pressure loss; pressure loss) is large, the collection plate 23 is thin and exhausted. Since the flow direction length of the gas flow is short, there is a concern that the PM may pass through, and there is a possibility that the PM collection efficiency cannot be sufficiently increased. The PM once passed through the collection plate 23 is charged again by corona discharge. There is a problem that it is feared that it will be collected without being collected.
In Patent Document 1, the collecting plate has a long tube shape in the flow direction of the exhaust gas flow, and an electrode needle is provided in the tube axis direction of the tubular collection portion, so that the PM particles flow in the flow of the exhaust gas flow. In addition to increasing the particle size of PM in the vicinity of the inner surface of the tubular collection part of the exhaust gas flow so that it can be easily collected by a cyclone. The technical idea of increasing the concentration of PM and selectively extracting the exhaust gas stream having a large PM particle size and concentrated to a high concentration and collecting them with a cyclone is not disclosed or suggested. .

In addition, the exhaust PM collection device described in Patent Document 2 and the exhaust gas purification device described in Patent Document 3 set both voltages to appropriate conditions because the discharge voltage and the collection deflection voltage are the same potential. In order to prevent the occurrence of sparks between the deflection electrode and the collection electrode, it is necessary to increase the distance between the deflection electrode and the collection electrode, and for this reason, the PM passing through the collection section without being collected increases. In order to reduce the collection efficiency, and to increase the collection efficiency, it is necessary to increase the capacity of the collection section. It has the disadvantage that it is.
In Patent Document 2, the collection electrode 32 is a tunnel-like electrode that serves as an exhaust passage, and an electrode assembly of the needle electrode 31 and the deflection electrode 36 is formed in the tunnel of the collection electrode 32. The shaft center is arranged in a substantially common manner, and a thick and long electrode assembly is inserted in almost the entire length of the tubular collecting portion to form a lattice shape. In the paragraph [0033] of the sixth embodiment, “...... the electrode rod 42 constituting one of the discharge electrode pair and the collection electrode pair is suspended along the center line of the fixed cylindrical body 41... A large-diameter exhaust port is provided on the side surface, and a downstream exhaust pipe 45 is fitted into the exhaust port .... "Paragraph [0035] states that" the rotating cylindrical portion 46 has a truncated conical shape with a small diameter at the bottom. ... A long bar (scraping part) 4 upward from the inner surface of the rotating cylindrical part 46 ”And the outer edge of the bar 44 is in contact with the inner surface of the large diameter portion of the fixed cylindrical body 41,” paragraph [0036] states that “...... diesel particulate is the electrode rod 42 in the discharge space. The charged diesel particulates are ... attracted by an electrostatic field and are deposited on the inner surface of the large diameter portion of the fixed cylinder 41. " Further, in paragraph [0037], “a diesel particulate layer deposited on the inner surface of the large-diameter portion as the bar 44 rotates at a low speed in contact with the inner surface of the large-diameter portion of the fixed cylindrical body 41 as the rotating cylindrical portion 46 rotates. The diesel particulates that fall are collected in a collection box and can be removed ... "and a tubular collection part is formed, but it is described in Patent Document 3. Things are collecting electrodes A fixed cylindrical portion (tubular) that is long in the flow direction of the exhaust gas flow is provided, and an electrode needle is provided while maintaining an interval in the tube axis direction of the tubular collection portion, so that PM flows in the flow direction of the exhaust gas flow. This is a technique for depositing and scraping the deposited PM particles with a bar, and a part of the PM particles scattered when scraped off is a downstream exhaust fitted into a large exhaust port provided in front of the collection box. It is a technology that is highly concerned about being discharged from the pipe.
Therefore, in the techniques described in Patent Documents 2 and 3, as in the technique described in Patent Document 1, the collecting plate has a tubular shape that is long in the flow direction of the exhaust gas flow. An electrode needle is provided in the direction of the tube axis of the tube, and the growth is caused by a jumping phenomenon that repeats deposition and separation while flowing PM particles in the flow direction of the exhaust gas flow. The particle size of PM is coarsened so that it can be easily collected by a cyclone, the concentration of PM is increased, and the exhaust gas stream having a large particle size and concentrated at a high concentration is selectively selected. The technical idea of extracting and collecting efficiently with a cyclone is neither disclosed nor suggested.

On the other hand, in the diesel engine exhaust gas purification device described in Patent Document 4, the dust collecting electrode 54 of the electric dust collector 51 and the inner peripheral wall surface (collecting tube wall) of the cylindrical housing 56 that is short in the flow direction of the exhaust gas. The collected PM particles form a large lump. The PM lump is separated from the dust collecting electrode 54 and the collecting tube wall by a natural peeling or mechanical peeling mechanism, and is mixed in the cylindrical housing 56. The PM lump mixed in this way is centrifuged in the cyclone 52 in the cyclone 52 and collected again in the hopper 63. In this method, the cylindrical housing 56 is short in the flow direction of the exhaust gas. cyclone by the guide vanes 61 in the mass sufficient particle size with the mixing of the total amount of exhaust gas at the expense of energy loss due to an increase in the flow-through resistance is disposed on the downstream side after the cylindrical housing 56 can not be coarsened In order to centrifuge the PM by flowing the entire amount of exhaust gas to No. 2, a large cyclone 52 having a large guide vane 61 is inevitably required, which increases the equipment cost and running cost, and is structurally cyclone. Since it is not possible to install a plurality of 52, it is not possible to cope with a large increase / decrease in the exhaust gas flow rate due to an increase or decrease in the number of operating engines or a large change in the engine load factor, and a means for appropriately controlling the exhaust gas flow rate at the cyclone introduction part Since it is not provided, it has the disadvantages of maintaining a high PM collection rate and not solving problems such as deterioration in fuel consumption due to excessive pressure loss in the cyclone.
In Patent Document 4, the collection plate has a long tubular shape in the flow direction of the exhaust gas flow, an electrode needle is provided in the tube axis direction of the tubular collection portion, and the PM particles are flowed in the exhaust gas flow. While flowing in the direction, it is deposited near the inner surface of the tubular collection part and collected by the cyclone. However, the technique described in Patent Document 4 is exhausted in the same manner as the techniques described in Patent Documents 1 to 3. The particle size of the gas flow PM is coarsened so that it can be easily collected by a cyclone, and the concentration of PM in the vicinity of the inner surface of the tubular collection portion of the exhaust gas flow is increased. However, there is no disclosure or suggestion of a technical idea of selectively extracting only the flow in the vicinity of the inner surface of the tubular collection portion of the exhaust gas flow concentrated to a high concentration and collecting it intensively with a cyclone.

Further, the gas processing apparatus described in Patent Document 5 is a small vehicle-mounted gas processing apparatus, which is configured by disposing the charging aggregation unit 70 on the upstream side and the filter unit 80 on the downstream side. A gas inlet chamber 71c that divides exhaust gas into a large number is provided in the agglomeration portion 70, a gas passage wall is formed of a cylindrical body 71f, and the cylindrical body 71f is exposed to the outside air to form the cylindrical body that is a gas passage wall 71f is a technology related to a device that forms a gas cooling part that cools a gas by natural convection and natural heat dissipation by heat radiation, and then remixes the separated exhaust gas in a gas outlet chamber 71d, and flows out from the tubular collecting part. This is different from a technique (the present invention described later) in which the exhaust gas is not remixed before the PM particle collecting step. The gas processing apparatus described in Patent Document 5 is provided with a turbulent flow promoting means 71e for the gas flow on the inner surface of the cylindrical body 71f or in the vicinity of the inner surface, and particularly the turbulent flow of gas near the surface of the cylindrical body. This has the disadvantage that the agitation action is promoted to increase the stirring action in the cross-sectional direction of the flow path.
In addition, the thing of this patent document 5 provides an electrode needle in the tube-axis direction of this tubular collection part while making a collection wall into the tubular cylindrical body long in the flow direction of exhaust gas flow, PM Although the particles are collected while being collected in the vicinity of the inner surface of the tubular collecting portion while flowing in the flow direction of the exhaust gas flow, this Patent Document 5 is also similar to Patent Documents 1 to 4 in the PM of the exhaust gas flow. The particle size of the exhaust gas is coarsened so as to be easily collected by a cyclone installed on the downstream side, and the concentration of PM in the vicinity of the inner surface of the tubular collection part of the exhaust gas flow is increased. In addition, the technical idea of selectively extracting only the flow in the vicinity of the inner surface of the tubular collecting portion of the exhaust gas flow having a high PM concentration and collecting it in a concentrated manner with a cyclone is not disclosed or suggested.

The present invention was made in order to eliminate the above-mentioned drawbacks of the prior art, and in particular, the diesel engine exhaust gas purification described in Patent Document 4 in which a guide vane is arranged in a passage through which the total exhaust gas amount flows to constitute a cyclone. Instead of the system of the apparatus, a system in which the cyclone type separation and collection means is arranged not in the tubular collection part but on the downstream side of the tubular collection part, and the cyclone collection means is constituted by a plurality of tangential cyclones. By adopting it, the cyclone can be reduced in size, and in the large-displacement marine diesel engine that uses low-quality fuel less than heavy oil , changes in the operating conditions and engine load due to the parallel operation and independent operation of the main engine and auxiliary machinery The cyclone can be selected and used appropriately according to the significant increase / decrease in the exhaust gas flow rate due to large fluctuations in the rate, etc. By providing a means for properly controlling the scan velocity, the oil following low quality fuel that can solve the problem of deterioration of fuel efficiency by excessive pressure loss in maintaining a high PM collection efficiency and the exhaust gas purifying device The present invention intends to provide an exhaust gas treatment device for a large displacement diesel engine to be used .

An exhaust gas treatment apparatus for a large displacement diesel engine using heavy oil or less low quality fuel according to the present invention includes a discharge electrode for charging PM contained in exhaust gas of a large displacement diesel engine using heavy oil or less low quality fuel, and It has a predetermined length tubular collecting part of which constitutes a dust collecting electrode for collecting the charged the PM, and the discharge electrode arrangement in the tube axis direction to collecting tube constituting the tubular collecting part Electric dust collecting means composed of a main electrode provided and a plurality of radially projecting electrode needles spaced from the main electrode, and PM separated from the tubular collecting portion are separated and collected. In an exhaust gas treatment apparatus for a large displacement diesel engine using a low quality fuel less than heavy oil equipped with a cyclone separation and collection means, a low concentration exhaust gas exhaust pipe for PM is provided in the vicinity of the axial center downstream of the tubular collection part. The tube A high-concentration exhaust gas deriving part is provided in the vicinity of the inner peripheral surface on the downstream side of the collecting part, and a cyclone collecting means for collecting the PM is connected to the PM high-concentration exhaust gas deriving part, and the cyclone collecting means is provided. constituted by a tangential cyclone, said to such a mechanism for controlling the exhaust gas inflow rate to the tangential cyclone by controlling the damper opening which is arranged in a low concentration exhaust gas outlet pipe, a longer of the collecting tube When the thickness is L and the inner diameter of the collection tube is D, the relationship satisfies the condition of 5D ≦ L ≦ 15D . Needless to say, low-concentration exhaust gas is exhaust gas having a low PM content (purified exhaust gas), and high-concentration exhaust gas is exhaust gas containing a large amount of PM.

  Further, the apparatus of the present invention comprises the cyclone collecting means constituted by a plurality of tangential cyclones, and the high concentration exhaust gas discharged from the high concentration exhaust gas deriving section is selectively selected according to the flow rate of the exhaust gas. It is characterized in that it becomes a method to be introduced into.

  In the device according to the present invention, the tubular collecting portion has a tapered tubular portion that expands in a tapered shape at a downstream end portion thereof, and a large-diameter tubular portion that is continuous with the tapered tubular portion, and an axial center of the large-diameter tubular portion It is a preferable aspect that a low concentration exhaust gas outlet pipe and a high concentration exhaust gas outlet portion are connected in the vicinity of the inner peripheral surface of the large diameter tubular portion.

  Further, it is preferable that the discharge electrode is extended to the tapered tubular portion of the tubular collection portion or the region of the tapered tubular portion and the large-diameter tubular portion connected to the tapered tubular portion. is there.

  The apparatus according to the present invention is preferably configured such that the cyclone collecting means includes a plurality of tangential cyclones having different processing capacities, and a flow rate control damper is provided at an inlet of each tangential cyclone. Between the tangential cyclone and the low-concentration exhaust gas outlet pipe, an exhaust pipe for merging the purified gas after passing the tangential cyclone with the low-concentration exhaust gas is provided, and an air nozzle or a motor-driven fan is provided in the exhaust pipe. It is a preferred embodiment to have a configuration in which is arranged.

  Furthermore, in the device according to the present invention, the tubular collecting part is arranged substantially horizontally, or the tubular collecting part is arranged substantially vertically and upward, or the tubular collecting part is substantially vertical and downward. It is a preferred embodiment that they are arranged in the above.

In the exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel of heavy oil or less according to the present invention, the relationship when the length of the collecting pipe is L and the inner diameter of the collecting pipe is D is 5D ≦ L ≦ 15D By adopting a method of centrifuging PM outside the tubular collection part having a long collection tube that satisfies the above conditions, the PM in the exhaust gas is tubular in the long tubular collection part. The PM mass is concentrated in the vicinity of the tubular collection wall surface while repeatedly adhering to and peeling from the long collection wall surface. As the exhaust gas flow contained in the pipe, it flows downstream, and the PM is gradually diluted in the vicinity of the high concentration exhaust gas of PM and the axial center of the tubular collection part. Separated into low-concentration exhaust gas that does not contain, high-concentration exhaust of PM Scan is an elongate collecting near the wall of a tubular, since the low concentration exhaust gas in the PM phenomena flowing near the axial center of the tubular collecting part respectively occurs, capturing tubular only high concentration exhaust gas PM enriched It can be led from the vicinity of the collecting wall to the cyclone collecting means. That is, according to the apparatus of the present invention, only a high concentration exhaust gas of PM can be guided to the cyclone although it is a part of the total exhaust gas amount, the cyclone can be downsized. On the other hand, low-concentration exhaust gas (purified exhaust gas) in which PM has been diluted is discharged to the outside from a low-concentration exhaust gas outlet pipe connected in the vicinity of the shaft center on the downstream side of the long tubular collection part.

  Further, according to the apparatus of the present invention, the cyclone collecting means is constituted by a plurality of tangential cyclones, and the high concentration exhaust gas of PM discharged from the high concentration exhaust gas deriving section is selectively selected according to the flow rate of the exhaust gas. By adopting a method of introducing into a cyclone type cyclone, the “flow-in” of a tangential type cyclone with superior collection performance compared to the axial flow type cyclone of the diesel engine exhaust gas purification device described in Patent Document 4 in which a guide vane is disposed. In addition to the effect that the trapping efficiency increases when the tangential speed of the fluid is high, the exhaust due to changes in the operating status of the marine engine due to the parallel operation or independent operation of the main engine and auxiliary machinery, or large fluctuations in the load factor of the engine The processing capacity and number of tangential cyclones can be selected appropriately according to the significant increase / decrease in the gas flow rate. It is possible to secure the rate. Furthermore, since the exhaust gas inflow rate (tangential velocity) to the tangential cyclone can be properly controlled by controlling the opening degree of the damper disposed in the low concentration exhaust gas outlet pipe, a high collection rate of PM In addition, problems such as deterioration in fuel consumption due to excessive pressure loss in the exhaust gas purification apparatus can be solved.

The exhaust gas treatment apparatus for a large displacement diesel engine using low-quality fuel of heavy oil or less according to the present invention is also a tapered tubular portion that expands in a tapered shape downstream of the tubular collection portion or a large diameter continuous to the tapered tubular portion. By providing the tubular portion, the high-concentration exhaust gas flow is gradually decelerated by the tapered tubular portion, and PM can be reliably introduced into the high-concentration exhaust gas outlet portion continuously provided on the inner peripheral surface of the large-diameter tubular portion. Furthermore, the PM is more effectively captured by adopting a configuration in which the discharge electrode is extended to the vicinity of the inner peripheral surface of the tapered tubular portion of the tubular collecting portion and the large-diameter tubular portion region connected to the tapered tubular portion. The exhaust gas can be collected and the exhaust gas can be further purified.

Furthermore, in the present invention apparatus, the cyclone collecting means is composed of a plurality of tangential cyclones having different processing capacities, for example, three types of cyclones: a small processing capacity tangential cyclone, a medium processing capacity tangential cyclone, and a large processing capacity tangential cyclone. In addition, by installing a flow control damper at the inlet of each tangential cyclone, the operating situation associated with the parallel operation and independent operation of the main engine and auxiliary machinery in a large displacement diesel engine for ships that uses low quality fuel below heavy oil Not only can the tangential cyclone be more appropriately selected and used in response to a significant increase or decrease in exhaust gas flow rate due to changes or large fluctuations in the engine load factor, but also a damper installed in the low concentration exhaust gas outlet pipe In addition, by controlling the flow control damper provided for each tangential cyclone, the exhaust to each tangential cyclone is reduced. It is possible to control the flow rate more properly. Furthermore, a discharge pipe is provided between the tangential cyclone and the low-concentration exhaust gas outlet pipe to join the purified gas after passing the tangential cyclone with the low-concentration exhaust gas, and an air nozzle is provided in the exhaust pipe. Alternatively, by adopting a configuration in which the motor drive fan is arranged, the purified gas flow after passing through the tangential cyclone is sucked at a higher speed, and the pressure loss in the exhaust gas purification device is further improved, contributing to the improvement of fuel consumption.

  In the present invention device, when the tubular collection part is arranged substantially horizontally, the tubular collection part is substantially constant with respect to the floor of the engine room where the engine is installed. When the maintenance work for the discharge electrode or the like is good, and when the tubular collecting part is arranged substantially vertically and upward with respect to the floor surface, the tubular collecting part is connected to the exhaust pipe to the chimney. Space can be saved, and when the tubular collection part is arranged substantially vertically and downward with respect to the floor surface, the falling PM is not only easily collected, but also captured. When SOF or sulfate adhering to the collecting wall liquefies, the liquid component easily flows down the collecting wall and collects even if heavy oxide scale corroded by the sulfate peels off from the wall and falls. Benefits such as easy to do It is.

It is a schematic longitudinal cross-sectional view which shows the whole structure of the 1st Example apparatus of this invention. It is a schematic longitudinal cross-sectional view which shows the whole structure of the 2nd Example apparatus of this invention. It is a schematic longitudinal cross-sectional view which expands and shows the principal part of the 3rd Example apparatus of this invention. It is a schematic longitudinal cross-sectional view which expands and shows the principal part of the modification of the 3rd Example apparatus of this invention. It is a schematic longitudinal cross-sectional view which expands and shows the principal part of the 4th Example apparatus of this invention. It is an expanded sectional view on the aa line of FIG. It is a schematic longitudinal cross-sectional view which abbreviate | omits and shows a part of whole structure of the 5th Example apparatus of this invention. It is explanatory drawing which shows typically the other Example of the cyclone collection means in this invention apparatus. FIG. 4 is an explanatory diagram schematically showing an enlarged speed-up suction portion of the purified gas after passing through a tangential cyclone in the apparatus of the present invention, where (a) shows an air nozzle system and (b) shows a motor-driven fan system. It is the schematic which shows the example which has arrange | positioned the tubular collection part in this invention apparatus substantially perpendicularly and downward. It is the schematic which shows the example which has arrange | positioned the tubular collection part in this invention apparatus substantially perpendicularly and upwards. It is a schematic longitudinal cross-sectional view which shows an example of the conventional diesel engine exhaust gas processing apparatus. It is a schematic longitudinal cross-sectional view which shows the other example of the conventional diesel engine exhaust gas processing apparatus. It is a schematic longitudinal cross-sectional view which shows another example of the conventional diesel engine exhaust gas processing apparatus. It is a schematic longitudinal cross-sectional view which shows another example of the conventional diesel engine exhaust gas processing apparatus. It is a general | schematic longitudinal cross-sectional view which shows another example of the conventional diesel engine exhaust gas processing apparatus partially fractured | ruptured. It is a partial expanded sectional view of the diesel engine exhaust gas processing apparatus shown in FIG.

FIG. 1 shows an exhaust gas treatment apparatus for a large displacement diesel engine using a low-quality fuel equal to or less than heavy oil shown as the first embodiment of the present invention. The tubular collecting part 1 which is composed of a separate collecting part 2 constituting a collecting means and provided for collecting PM particles has a collecting wall surface 1-1k having a predetermined length constituting a dust collecting electrode. A collection tube 1-1 and a discharge electrode 1-2 for charging PM contained in the exhaust gas are provided. The collection tube 1-1 constituting the dust collection electrode has an exhaust gas introduction port 1-1a at an end portion on the upstream side (diesel engine side), and a low concentration of PM in the vicinity of the axial center of the downstream end portion. The exhaust gas outlet pipe 3 is provided with a PM high-concentration exhaust gas outlet portion 1-1b in the vicinity of the inner peripheral surface of the downstream end. The discharge electrode 1-2 is arranged at a desired interval in the longitudinal direction of the main electrode 1-2a extending substantially over the entire length around the axial center of the collection tube 1-1 constituting the dust collection electrode. And a group of electrode needles 1-2b protruding radially. The discharge electrode 1-2 configured as described above is provided at the inlet portion of the seal air introduction pipe portion 1-1c provided on the exhaust gas introduction port 1-1a side of the collection pipe 1-1 and the low concentration exhaust gas outlet pipe 3. Both ends of the main electrode 1-2a are supported through a support body 4 suspended from the provided seal air introduction pipe section 3-1. Although not shown, the discharge electrode 1-2 is supported at a desired interval by a stay insulated from the inside of the collecting tube 1-1 as necessary. Further, the discharge electrode 1-2 is supplied with a controlled high voltage power source by being wired to a high voltage power source device (not shown) installed outside.

The fraction collection part 2 provided in the downstream of the tubular collection part 1 in the flow direction of the exhaust gas is composed of a cyclone collection means 2-1 as a separation means. The cyclone collecting means 2-1 is composed of one tangential cyclone 2-1a connected to the high concentration exhaust gas deriving portion 1-1b of the collecting pipe 1-1 via a communication pipe 5-1. Further, between the tangential cyclone 2-1a and the low concentration exhaust gas outlet pipe 3, the purified gas after passing through the tangential cyclone 2-1a is joined to the low concentration exhaust gas flowing in the low concentration exhaust gas outlet pipe 3. A discharge pipe 6-1 is provided. The low-concentration exhaust gas outlet pipe 3 is provided with a flow control damper 7 for adjusting the flow rate of the high-concentration exhaust gas flow rate and flow rate into the tangential cyclone 2-1a and the low-concentration exhaust gas discharge rate.
In addition, the chain line part of FIG. 1 illustrates the combination of the main engine 12 and the auxiliary machine 13 in the marine large displacement diesel engine which uses the low quality fuel below heavy oil . In the case of a marine large displacement diesel engine using a low quality fuel less than this heavy oil , the engine operation includes the parallel operation of the main engine 12 and the auxiliary machine 13 and the independent operation of each, and the load on each engine also varies greatly, so the exhaust gas flow total amount Will fluctuate significantly. Further, in the case of a large displacement engine using a low quality fuel less than heavy oil , a plurality of the collecting pipes 1-1 may be arranged in parallel (not shown).

FIG. 2 shows an exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel less than heavy oil shown as the second embodiment of the present invention. The exhaust gas treatment apparatus for a large displacement diesel engine includes two tangential cyclones 2-1a. Except for the configuration described above, the configuration is the same as that of the first embodiment apparatus. That is, two tangential cyclones 2-1a are connected in parallel to the high-concentration exhaust gas deriving portion 1-1b of the collecting pipe 1-1 via the communication pipes 5-1, 5-2, and the cyclone collecting means. In this case, the exhaust pipes 6-1, 6- 6 for joining the purified gas after passing through each tangential cyclone 2-1a to the low-concentration exhaust gas flowing in the low-concentration exhaust gas outlet pipe 3 respectively. 2 is disposed.

In the exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel less than heavy oil shown in FIGS. 1 and 2, PM in the exhaust gas flowing into the collection pipe 1-1 from the exhaust gas inlet 1-1a is Since it is charged by the discharge between the collection wall 1-1k, which is the inner wall of the collection tube 1-1 constituting the dust collection electrode, and the discharge electrode 1-2, the charged PM particles are captured by the Coulomb force. Collected on the collecting wall 1-1k. The PM particles collected on the collection wall surface 1-1k of the collection tube 1-1 are further accumulated with the PM particles collected from the exhaust gas flow near the axis with the passage of time, and gradually grow to form a lump. This PM mass flows while being concentrated in the vicinity of the collection wall surface while repeatedly adhering to the tubular collection wall surface 1-1k by the Coulomb force due to separation and discharge (charging) due to the exhaust flow. As a result, the PM in the exhaust gas flowing in the vicinity of the axial center of the collection pipe 1-1 is collected on the collection wall 1-1k and gradually diluted to a low concentration. However, it becomes an exhaust gas flow containing only PM and flows downstream. That is, the exhaust gas flowing into the collection pipe 1-1 from the exhaust gas introduction port 1-1a is separated into a PM high-concentration exhaust gas stream and a low-concentration exhaust gas stream in the process of flowing down the tubular collection section 1, and the collection pipe 1-1 The high-concentration exhaust gas flow near the collection wall surface 1-1k of the inner wall becomes a low-concentration exhaust gas flow near the axial center of the collection tube 1-1 and flows downstream of the collection tube 1-1. To go. And in the case of the exhaust gas treatment apparatus for a large displacement diesel engine using the low quality fuel below the heavy oil shown in FIG. 1, the collection wall surface 1- 1 of the inner wall of the collection tube 1-1 is downstream of the collection tube 1-1. The high-concentration exhaust gas flow of PM flowing in the vicinity of 1k is introduced into the tangential cyclone 2-1a from the high-concentration exhaust gas deriving unit 1-1b of the collection pipe 1-1 through the communication pipe 5-1, and PM. In the case of an exhaust gas treatment device for a large displacement diesel engine that uses a low-quality fuel equal to or less than heavy oil shown in FIG. 2, the high flow that has flowed in the vicinity of the collection wall 1-1k of the inner wall of the collection tube 1-1 Concentrated exhaust gas flow is introduced into the two tangential cyclones 2-1a from the high concentration exhaust gas deriving unit 1-1b of the collection pipe 1-1 through the communication pipes 5-1, 5-2, and the PM is centrifuged. To be separated. On the other hand, the PM low-concentration exhaust gas flow that flows almost in the vicinity of the axial center of the collection pipe 1-1 is the same as that of the exhaust gas treatment apparatus for large-displacement diesel engines using low-quality fuel below heavy oil shown in FIGS. It is discharged to the outside through the low-concentration exhaust gas outlet pipe 3 installed in the vicinity of the axial center of the collection pipe 1-1. The exhaust gas flow purified by the tangential cyclone 2-1a is joined to the low-concentration exhaust gas flow flowing through the low-concentration exhaust gas outlet pipe 3 through the exhaust pipes 6-1, 6-1 and 6-2, respectively. The
In the case of the exhaust gas treatment apparatus for a large displacement diesel engine using the low quality fuel below the heavy oil shown in FIG. 2 in which the cyclone collecting means 2-1 is constituted by two tangential cyclones 2-1a, a high concentration exhaust gas is used. What is necessary is just to set the number of units used according to the flow volume of the high concentration exhaust gas flow discharged | emitted from the derivation | leading-out part 1-1b, and can also use two tangential type cyclones 2-1a alternately.

As described above, in the case of the exhaust gas treatment device for a large displacement diesel engine using the low quality fuel of the present invention or less shown in FIG. 1 and FIG. 2, only high concentration exhaust gas of PM (a part of the total exhaust gas amount) Therefore, PM can be efficiently collected and separated and collected with a small cyclone.

Next, an exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel equal to or lower than heavy oil shown as the third embodiment apparatus in FIG. 3 is a collection pipe 1-constituting a dust collection electrode of the tubular collection section 1. 1 is formed with a tapered tubular portion 1-1d having a tapered diameter and a large-diameter tubular portion 1-1e connected to the tapered tubular portion, and in the vicinity of the axial center portion of the large-diameter tubular portion 1-1e. low concentrations except that the exhaust gas outlet pipe 3 and configuration provided continuously high concentration exhaust gas outlet portion 1-1b near the inner circumferential surface, a large amount of the exhaust gas using the following low quality heavy fuel oil as shown in FIG. 1 or FIG. 2 It has the same configuration as the exhaust gas treatment device for diesel engines. In the case of an exhaust gas treatment device for a large displacement diesel engine that uses a low-quality fuel of heavy oil or less having such a configuration, a high-concentration exhaust gas flow is gradually caused by a tapered tubular portion 1-1d at the downstream end of the collection tube 1-1. Therefore, PM can be surely introduced into the high concentration exhaust gas deriving portion 1-1b provided in the vicinity of the inner peripheral surface of the large diameter tubular portion 1-1e. It is more preferable that the electrode needle 1-2d of the discharge electrode 1-2 is continuously provided up to the tapered tubular portion 1-1b at the downstream end of the collection tube 1-1.

Further, in the exhaust gas treatment apparatus for a large displacement diesel engine using the low quality fuel below the heavy oil shown in FIG. 3, when the collection pipe 1-1 is vertically arranged as shown in FIG. The bottom wall surface 1-1e 'of the radial tubular portion 1-1e is inclined downward toward the communication tube 5-1 as shown in the drawing. This means is used to make it easier for liquid components such as SOF and sulfate to flow down to the cyclone and to collect them, and the collection wall surface 1-1k on the inner surface of the collection tube 1-1 is made of PM, sulfate, etc. This is to make it easier to collect the oxide scale peeled off from the collection wall surface 1-1k when an oxide scale (metal oxide scale or the like) is generated due to corrosion due to the above.

Moreover, the exhaust gas treatment apparatus for a large displacement diesel engine using a low quality fuel equal to or less than heavy oil shown as the fourth embodiment apparatus in FIGS. 5 and 6 is a collection pipe constituting the dust collection electrode of the tubular collection section 1. 1-1, a tapered tubular portion 1-1d whose diameter is increased in a tapered shape and a large-diameter tubular portion 1-1e connected to the tapered tubular portion are formed at the downstream end of 1-1, and the axial center of the large-diameter tubular portion 1-1e A low-concentration exhaust gas outlet pipe 3 and a high-concentration exhaust gas outlet part 1-1b are connected in the vicinity of the inner peripheral surface, and the tapered tubular part 1-1d and the large-diameter tubular part 1 connected to the tapered tubular part. 1e, except that the main electrode 1-2a and the electrode needle 1-2b of the discharge electrode 1-2 are extended to the region 1e, and the low quality fuel below the heavy oil shown in FIG. 1 or 2 is used. those having the same configuration as the large engine diesel engine exhaust gas treatment apparatus for In addition, 1-2c in a figure is a support ring which supports each of the discharge electrode 1-2 branched into plurality.
In the case of an exhaust gas treatment device for a large displacement diesel engine that uses a low-quality fuel of heavy oil or less having such a configuration, a high-concentration exhaust gas flow is gradually caused by a tapered tubular portion 1-1d at the downstream end of the collection tube 1-1. In addition to being able to collect PM more effectively, the PM mass grows even after flowing into the large-diameter tubular portion 1-1e and is captured by the cyclone collecting means 2-1. The exhaust gas can be further purified by increasing the collection efficiency.

Furthermore, an exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel less than heavy oil shown as a fifth embodiment apparatus in FIG. 7 includes an exhaust gas introduction chamber 1-1f in front of the collection pipe 1-1, A throttle part 1-1g and a taper enlarged part 1-1h are provided between the exhaust gas introduction chamber 1-1f and the collecting pipe 1-1, and the throttle part 1-1g and the taper enlarged part 1-1h are also provided. An electrode needle 1-2b is provided, and an exhaust gas introduction port 1-1a to the exhaust gas introduction chamber 1-1f and a seal air introduction port 1-1j to the seal air introduction chamber 1-1i are provided to face each other. It is what became.
In an exhaust gas treatment apparatus for a large displacement diesel engine using a low quality fuel of heavy oil or less having such a configuration, when the length of the collection pipe 1-1 is L and the inner diameter of the collection pipe 1-1 is D, 3D ≦ It is preferable to satisfy the condition of L ≦ 15D, preferably 5D ≦ L ≦ 10D. The reason is that if the flow is less than 3D, the flow of exhaust gas cannot be rectified and the turbulence cannot be suppressed, so the concentration of PM at the collecting wall 1-1k portion is not promoted. This is because the size of the apparatus is increased and the space efficiency is deteriorated. In addition, 5D ≦ L ≦ 10D as a preferable condition is that if 5D or more, the flow is particularly well rectified and the concentration of PM near the collecting wall 1-1k is stable, and the concentration is within 10D. This is because the size of the apparatus can be suppressed and the increase in size of the apparatus can be suppressed. In addition, when an example of the dimension of each part is shown concretely, the length L of the collection tube 1-1 is 3 m, the inner diameter D of the collection tube 1-1 is φ400 mm , and the relationship between L and D is 5D ≦ L ≦ 10D L = 7.5D satisfying the above condition, the length of the throttle part 1-1g is 375 mm, the inner diameter of the throttle part 1-1g is φ220 mm, and the taper angle θ of the taper enlarged part 1-1h is 30 degrees. .
Further, the exhaust gas flowing into the exhaust gas introduction chamber 1-1f from the exhaust gas introduction port 1-1a is prevented from being disturbed by the exhaust gas flow through the tapered enlarged portion 1-1h through the throttle portion 1-1g. The flow is quickly stabilized and the concentration of the inner wall of the collecting tube at the collecting wall surface 1-1k and the dilution near the collecting tube axis are promoted. In addition, since the distance between the electrode and the particle is short in the narrowed portion 1-1g, all the particles can be reliably charged, and the particles are attached to the collecting wall surface 1-1k of the inner wall of the collecting tube to improve the collecting performance. Is peeled off. The reason why the exhaust gas is opposed to flow into the exhaust gas introduction chamber 1-1f is that the flow of the exhaust gas flow is balanced by causing the exhaust gas to flow into the collection pipe 1-1 symmetrically, and the disturbance of the exhaust gas flow is caused. This is because the flow is reduced and quickly rectified, and is well rectified while having a short axial length. Further, it is also preferable that the seal air with respect to the electrode is made to face and flow into the seal air introduction chamber 1-1i.

Next, the cyclone collecting means shown in FIG. 8 includes a plurality of tangential cyclones having different throughputs, for example, a small throughput tangential cyclone 2-1b, a medium throughput tangential cyclone 2-1c, and a large throughput tangential cyclone. It is composed of three types of cyclones 2-1d, and is connected to communication pipes 8-1, 8-2, and 8-3 connected to the high concentration exhaust gas deriving portion 1-1b of the collecting pipe 1-1 in a radial position. The tangential cyclones 2-1b, 2-1c, and 2-1d are connected to the high-concentration exhaust gas inlets of the communication pipes 8-1, 8-2, and 8-3. -2 and 9-3.
In this way, when the cyclone collecting means is composed of a plurality of tangential cyclones with different processing capacities, changes in the operating conditions accompanying the parallel operation and independent operation of the main engine and auxiliary machinery in a large displacement diesel engine for ships, Each tangential cyclone can be selected and used more appropriately in response to the exhaust gas flow rate that changes in accordance with the load factor, and each tangent is combined with a damper disposed in the low concentration exhaust gas outlet pipe 3. By controlling the flow control dampers 9-1, 9-2, 9-3 provided for each type cyclone, it becomes possible to more appropriately control the inflow tangential speed of the exhaust gas to each tangential type cyclone, and high collection Efficiency can be secured and maintained over a wide range of engine load factors.

  Further, as shown in FIGS. 9 (a) and 9 (b), the purified gas after passing through the tangential cyclone is connected to a discharge pipe 6-1 arranged to join the purified gas after passing through the tangential cyclone with the low-concentration exhaust gas. By installing the air nozzle 10 for speeding up suction or the fan 11 driven by the motor 11-1, the purified gas flow after passing through the tangential cyclone is given kinetic energy and suctioned at a speed, It is improved so that the pressure loss in the exhaust gas purifying apparatus is also reduced, and the fuel consumption can be improved.

  Further, FIGS. 10 and 11 respectively show a tubular collecting portion 1 in the apparatus of the present invention, for example, 1-1e that expands in a taper shape at the downstream end of the collecting tube 1-1 shown in FIGS. FIG. 10 shows an example in which the tubular collecting part 1 is arranged substantially perpendicular to the engine room floor, FIG. 10 shows an example in which the tubular collecting part 1 is arranged substantially vertically and downward, and FIG. 11 shows the tubular collecting part. An example in which the collecting unit 1 is arranged substantially vertically and upward is shown. Here, as shown in FIG. 10, when the tubular collection part 1 is arranged substantially vertically and downward, the tubular collection part 1 can also serve as an exhaust pipe piping to a chimney (not shown). Therefore, there is an advantage that space saving can be taken. On the other hand, when the tubular collecting portion 1 is arranged vertically and upward as shown in FIG. 11, not only the falling PM is easily collected, but also SOF, sulfate, etc. adhering to the collecting wall surface are liquefied. In this case, there is an advantage that the liquid component easily flows down the collecting wall surface and is easily collected even if a heavy oxide scale corroded by sulfate or the like peels off from the wall surface and falls. In addition, when the tubular collection part 1 is arrange | positioned substantially horizontal, since the tubular collection part 1 becomes substantially constant height with respect to the floor surface of the engine room in which the engine is installed, a collection tube, a discharge electrode, etc. There is an advantage that workability during maintenance is good.

Since the exhaust gas treatment apparatus for a large displacement diesel engine according to the present invention is a system for purifying exhaust gas by introducing a partial flow of the total exhaust gas amount, which has been concentrated in advance and enriched, into the cyclone. The cyclone collecting means is composed of a plurality of tangential cyclones, and the high concentration exhaust gas flow of PM discharged from the high concentration exhaust gas deriving section is selectively selected according to the flow rate of the exhaust gas. In addition to the effects of a tangential cyclone with better collection performance than an axial flow type cyclone, the main engine and auxiliary machine in a large displacement diesel engine for marine engines that use low quality fuel below heavy oil can be used in parallel. Processing capacity of tangential cyclone in response to a drastic increase or decrease in exhaust gas flow rate (velocity) due to changes in operating conditions due to operation or single operation or fluctuations in engine load factor It is possible to make a proper selection while balancing the number of units and the number of units to ensure and maintain a high PM collection rate corresponding to each change in the exhaust gas flow rate. By controlling the opening of the installed damper, the inflow tangential speed of the exhaust gas to the tangential cyclone can be controlled appropriately, so that a high PM collection rate is secured and maintained and the exhaust gas purification device Since it has many excellent effects, such as the problem of deterioration of fuel consumption due to excessive pressure loss can be solved, it is less than heavy oil using low quality fuel less than heavy oil for various uses such as marine, vehicle, industrial etc. This greatly contributes to the purification of exhaust gas for large displacement diesel engines that use low quality fuel .

DESCRIPTION OF SYMBOLS 1 Tubular collection part 1-1 Collection pipe 1-1a Exhaust gas inlet 1-1b High concentration exhaust gas extraction part 1-1c Seal air introduction pipe part 1-1d Tapered tubular part 1-1e Large diameter tubular part 1-1f Exhaust gas Introduction chamber 1-1g Restriction portion 1-1h Tapered diameter expansion portion 1-1i Seal air introduction chamber 1-1j Seal air introduction port 1-1k Collection wall surface 1-2 Discharge electrode 1-2a Main electrode 1-2b Electrode needle 1 -2c Support ring 2 Separation collection part 2-1 Cyclone collection means 2-1a Tangential cyclone 2-1b Small throughput tangential cyclone 2-1c Medium throughput tangential cyclone 2-1d Large throughput tangential cyclone 3 Low concentration exhaust gas outlet pipe 3-1 Seal air introduction pipe section 4 Support body 5-1, 5-2, 8-1, 8-2, 8-3 Communication pipe 6-1, 6-2 Discharge pipe 7, 9- 1, 9-2, 9-3 Flow rate Please damper 10 air nozzle 11 fan 11-1 motor 12 main engine 13 auxiliary

Claims (6)

A tubular electrode of a predetermined length that constitutes a discharge electrode for charging particulate matter contained in the exhaust gas of a large displacement diesel engine using heavy oil or lower quality fuel, and a dust collecting electrode for collecting the charged particulate matter. It has a collecting unit, and the discharge electrode is a plurality of radially protruding, which is the interval provided to the main electrode and the main electrode disposed in the pipe axis direction in the collecting tube constituting the tubular collecting part In the exhaust gas treatment apparatus for a diesel engine, comprising: the electrostatic dust collecting means constituted by the electrode needles; and the cyclone type separation collecting means for separating and collecting the particulate matter separated from the tubular collecting portion. A particulate matter low-concentration exhaust gas outlet pipe is provided in the vicinity of the shaft downstream of the collection part, and a high-concentration exhaust gas outlet part is provided in the vicinity of the inner peripheral surface downstream of the tubular collection part. The granular material in the outlet The cyclone collecting means to be collected is connected continuously, the cyclone collecting means is constituted by a tangential cyclone, and the opening degree of the damper disposed in the low-concentration exhaust gas outlet pipe is controlled to thereby connect the cyclone collecting means to the tangential cyclone. it such a mechanism for controlling the exhaust gas inflow rate, further the length of the collecting tube L, if the inner diameter of the collecting tube was D, a feature that the relationship of 5D ≦ L ≦ 15D satisfy Exhaust gas treatment equipment for large-displacement diesel engines that uses low-quality fuel that is less than heavy oil . The cyclone collecting means is composed of a plurality of tangential cyclones, and the high concentration exhaust gas discharged from the high concentration exhaust gas deriving section is selectively introduced into the tangential cyclone according to the flow rate of the exhaust gas. The exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel equal to or less than heavy oil according to claim 1. The tubular collecting portion has a tapered tubular portion that expands in a tapered shape at a downstream end thereof and a large-diameter tubular portion that continues to the tapered tubular portion, and a low-concentration exhaust gas near the axial center of the large-diameter tubular portion large that uses heavy oil following low quality fuels according to the vicinity of the inner peripheral surface of the outlet pipe and university diameter pipe-shaped part to claim 1 or 2 high concentration exhaust gas outlet portion and wherein the configuration and Nasukoto which is continuously provided respectively Exhaust gas treatment equipment for diesel engines. The low quality of heavy oil or less according to claim 3, wherein the discharge electrode is extended to a region of a tapered tubular portion of the tubular collecting portion or a large-diameter tubular portion connected to the tapered tubular portion. Exhaust gas treatment equipment for large displacement diesel engines using fuel . The cyclone collecting means is constituted by a plurality of tangential cyclones having different processing capacities, and a flow rate control damper is provided at the inlet of each tangential cyclone. Exhaust gas treatment equipment for large displacement diesel engines using low quality fuel below the stated heavy oil . Between the tangential cyclone and the low-concentration exhaust gas outlet pipe, a discharge pipe for merging the purified gas after passing the tangential cyclone with the low-concentration exhaust gas is disposed, and an air nozzle or a motor drive is provided in the exhaust pipe. The exhaust gas treatment apparatus for a large displacement diesel engine using low quality fuel equal to or less than heavy oil according to any one of claims 1 to 5, wherein a fan is arranged.

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