JP2022060659A - Piping device - Google Patents

Abstract

A piping system for introducing exhaust gas into an EGR unit and capable of effectively removing dust and desulfurizing the exhaust gas is provided. A piping device according to one aspect of the present application includes an exhaust gas introduction pipe for introducing exhaust gas into an EGR unit, a pipe nozzle for injecting a cleaning liquid into the inside of the exhaust gas introduction pipe, and a pipe nozzle inside the exhaust gas introduction pipe. and a stirring part located downstream of the washing machine and stirring the passing exhaust gas and the cleaning liquid. [Selection drawing] Fig. 1

Description

The present application relates to a piping device that introduces exhaust gas into an EGR unit.

Exhaust gas recirculation (EGR), in which a part of exhaust gas is recirculated to the engine, is known as a technique for reducing nitrogen oxides (NOx) emitted from the engine. In the EGR unit of a large marine engine that uses heavy oil as fuel, the introduced exhaust gas is washed with a cleaning liquid, soot dust is removed (dust removal) and sulfur oxides are removed (desulfurization), and then the exhaust gas is recirculated to the engine (recirculation). For example, see Patent Document 1).

Japanese Patent No. 5807124

As described above, the EGR unit performs dust removal and desulfurization of exhaust gas, but there are cases where the EGR unit alone cannot sufficiently remove dust and desulfurize. Therefore, as a result of the research conducted by the inventors of the present application, it was found that it is effective to remove dust and desulfurize the exhaust gas having a relatively large flow velocity before being introduced into the EGR unit.

The present application has been made in view of the above circumstances, and is a piping device for introducing exhaust gas into an EGR unit, and provides a piping device capable of effectively removing and desulfurizing exhaust gas. I am aiming.

The piping device according to one aspect of the present application includes an exhaust gas introduction pipe that introduces exhaust gas into the EGR unit, a piping nozzle that injects a cleaning liquid into the exhaust gas introduction pipe, and a piping nozzle inside the exhaust gas introduction pipe. Also located downstream, it is equipped with a stirring unit that stirs the passing exhaust gas and cleaning liquid.

According to this configuration, the exhaust gas and the cleaning liquid are agitated in the exhaust gas introduction pipe where the flow velocity is relatively large, so that the contact between the exhaust gas and the cleaning liquid is promoted, and as a result, the exhaust gas can be effectively dust-removed and desulfurized. ..

According to the above configuration, it is possible to provide a piping device for introducing exhaust gas into the EGR unit, which can effectively remove and desulfurize the exhaust gas.

FIG. 1 is a schematic diagram of an engine system including a piping device. FIG. 2 is a perspective view of the stirring unit.

(Engine system)
First, the overall configuration of the engine system 100 including the piping device 30 according to the embodiment will be described. FIG. 1 is a schematic configuration diagram of an engine system 100.

The engine system 100 of the present embodiment is an engine system for a large ship and includes an engine 10. The engine 10 of the present embodiment is a 2-stroke diesel engine, but other engines may be used. The exhaust gas discharged from the engine 10 flows into the exhaust pipe 11. A part of the exhaust gas flowing into the exhaust pipe 11 flows toward the supercharger 12, and the supercharger 12 is rotationally driven by the energy of the passing exhaust gas.

On the other hand, the other part of the exhaust gas that has flowed into the exhaust pipe 11 passes through the piping device 30 and the EGR unit 20 and is recirculated to the engine 10. As described above, the supercharger 12 is rotationally driven by the exhaust gas, whereby the supercharger 12 boosts the fresh air taken in from the outside. The boosted fresh air merges with the exhaust gas that has passed through the EGR unit 20 to form a scavenging air, and the formed scavenging air is supplied to the engine 10 via the scavenging pipe 13.

(EGR unit)
Subsequently, the EGR unit 20 will be described in detail. The EGR unit 20 is a unit that supplies the taken-in exhaust gas to the engine 10 in a state where it can be recirculated. The EGR unit 20 includes a scrubber nozzle 21, a gas cooler 22, a mist catcher 23, and a liquid storage tank 24. Hereinafter, these components will be described in order.

The scrubber nozzle 21 is located near the inlet of the EGR unit 20, and injects a cleaning liquid for cleaning the exhaust gas introduced into the EGR unit 20. The scrubber nozzle 21 of the present embodiment sprays the cleaning liquid toward the gas cooler 22 located downstream. However, the scrubber nozzle 21 may spray the cleaning liquid by any other method. Further, the number of scrubber nozzles 21 is not particularly limited.

The gas cooler 22 is a portion that cools the exhaust gas taken into the EGR unit 20. Since the exhaust gas flowing into the gas cooler 22 contains a large amount of water, condensed water is generated when the exhaust gas passes through the gas cooler 22. The exhaust gas is cleaned by coming into contact with the condensed water and the cleaning liquid jetted from the scrubber nozzle 21 or the like, and PM, SOx and the like are removed from the exhaust gas.

The mist catcher 23 is located downstream of the gas cooler 22 and is a portion that collects water contained in the exhaust gas. The water collected by the mist catcher 23 is stored in the liquid storage tank 24 located below the mist catcher 23. On the other hand, the exhaust gas that has passed through the mist catcher 23 is boosted by the EGR blower 25 and then merges with the fresh air boosted by the supercharger 12.

The liquid storage tank 24 is located below the mist catcher 23, and is a portion that receives the condensed water generated by the gas cooler 22 and the cleaning liquid sprayed from the scrubber nozzle 21 or the like and temporarily stores the liquid storage tank 24. The condensed water and the cleaning liquid stored in the liquid storage tank 24 are collected by the circulation pump 26 and supplied to the scrubber nozzle 21. That is, the condensed water and the cleaning liquid stored in the liquid storage tank 24 are used again as the cleaning liquid.

(Piping equipment)
Subsequently, the piping device 30 according to the present embodiment will be described in detail. The piping device 30 includes an exhaust gas introduction pipe 31, a piping nozzle 32, and a stirring unit 33. Hereinafter, these components will be described in order.

The exhaust gas introduction pipe 31 is a pipe for introducing exhaust gas into the EGR unit 20. The exhaust gas introduction pipe 31 of this embodiment is located between the exhaust pipe 11 and the EGR unit 20. The exhaust gas introduction pipe 31 of the present embodiment has a circular cross section and extends so as to be partially bent (curved). However, the cross-sectional shape of the exhaust gas introduction pipe 31 does not have to be circular, and the entire exhaust gas introduction pipe 31 may extend in a straight line. The exhaust gas inside the exhaust gas introduction pipe 31 flows along the central axis 36 (see FIG. 2) passing through the center of the exhaust gas introduction pipe 31 up to the stirring unit 33 described later. The flow velocity of the exhaust gas flowing in the exhaust gas introduction pipe 31 is larger than the flow velocity of the exhaust gas flowing in the EGR unit 20.

The pipe nozzle 32 is a nozzle that injects a cleaning liquid into the exhaust gas introduction pipe 31. The circulation pump 26 described above collects the cleaning liquid from the liquid storage tank 24 and supplies it not only to the scrubber nozzle 21 but also to the piping nozzle 32. The piping nozzle 32 injects the cleaning liquid supplied from the circulation pump 26. The direction of injection of the cleaning liquid by the piping nozzle 32 and the number of piping nozzles 32 are not particularly limited.

The stirring unit 33 is a part that stirs the passing exhaust gas and the cleaning liquid. As shown in FIG. 1, the stirring unit 33 is located inside the exhaust gas introduction pipe 31 and downstream of the pipe nozzle 32. In the present embodiment, the stirring unit 33 is provided in the straight line portion of the exhaust gas introduction pipe 31. The portion of the exhaust gas introduction pipe 31 provided with the stirring portion 33 may be configured so as to be separated from other portions.

FIG. 2 is a perspective view of the stirring unit 33. As shown in FIG. 2, the stirring unit 33 of the present embodiment has a first swivel member 34 and a second swivel member 35. The distance between the first swivel member 34 and the second swivel member 35 in the axial direction is about 1 to 3 times the thickness of the first swivel member 34 (or the second swivel member 35). The stirring unit 33 is shown by increasing the distance between the axial directions so that the structures of the members 34 and 35 can be easily grasped.

The first swivel member 34 is formed of a disk-shaped plate material and is fixed to the inside of the exhaust gas introduction pipe 31. The first swivel member 34 is arranged perpendicular to the central axis 36 of the exhaust gas introduction pipe 31. Further, the first swivel member 34 is formed with a plurality of inner flow path ports 37 so as to surround the central shaft 36, and a plurality of outer flow path ports 38 are formed so as to surround these inner flow path ports 37.

An inner swivel guide blade 39 extending downstream and tilting counterclockwise is provided at the edge of each inner flow path port 37. Further, an outer swivel guide blade 40 extending downstream and tilting counterclockwise is provided at the edge of each outer flow path port 38. Therefore, the exhaust gas and the cleaning liquid flowing in the direction of the central shaft 36 inside the exhaust gas introduction pipe 31 are guided by the inner swivel guide blade 39 and the outer swivel guide blade 40 when passing through the first swivel member 34, and are guided around the central shaft 36. Turns in the first turning direction 41 (counterclockwise in FIG. 2).

The second swivel member 35 is formed of a disk-shaped plate material and is fixed to the inside of the exhaust gas introduction pipe 31. The second swivel member 35 is arranged perpendicular to the central axis 36 of the exhaust gas introduction pipe 31. Further, the second swivel member 35 is formed with a plurality of inner flow path openings 42 so as to surround the central shaft 36, and a plurality of outer flow path openings 43 are formed so as to surround these inner flow path openings 42.

An inner swivel guide blade 44 extending downstream and inclined clockwise is provided at the edge of each inner flow path port 42. Further, an outer swivel guide blade 45 extending downstream and tilting clockwise is provided at the edge of each outer flow path port 43. Therefore, the exhaust gas and the cleaning liquid that have passed through the first swivel member 34 are guided by the inner swivel guide blade 44 and the outer swivel guide blade 45 when passing through the second swivel member 35, and are guided in the second swivel direction around the central axis 36. Turn 46 (clockwise in FIG. 2).

As described above, in the stirring unit 33 of the present embodiment, the exhaust gas and the cleaning liquid are swirled in the first swirling direction by the first swirling member 34 to stir, and then the exhaust gas and the cleaning liquid are swirled in the first swirling direction by the second swirling member 35. It is swirled in the second swirling direction opposite to that of the above and stirred. As a result, the contact between the exhaust gas and the cleaning liquid is promoted, and the exhaust gas can be effectively dust-removed and desulfurized.

In addition, at least one of the first swivel member 34 and the second swivel member 35 may have a large number of through holes formed as a whole. For example, the first swivel member 34 and the second swivel member 35 may be formed by a plate material on which a large number of through holes are formed. According to this configuration, it is possible to suppress the resistance when the exhaust gas passes through the first swivel member 34 and the second swivel member 35, and as a result, it is possible to suppress the pressure drop of the exhaust gas introduced into the EGR unit 20. ..

Further, as described above, the stirring unit 33 of the embodiment includes the first swivel member 34 and the second swivel member 35. However, the stirring unit 33 may include only one of the first swivel member 34 and the second swivel member 35, and includes other swivel members in addition to the first swivel member 34 and the second swivel member 35. May be.

Further, the stirring unit 33 of the embodiment swirls the exhaust gas and the cleaning liquid by using the first swirling member 34 and the second swirling member 35, thereby stirring the exhaust gas and the cleaning liquid. However, the stirring unit 33 may swirl the exhaust gas and the cleaning liquid by using a member other than the first swirling member 34 and the second swirling member 35. For example, the stirring unit 33 has a plurality of guide pipes, and each guide pipe may be configured to deflect the exhaust gas and the cleaning liquid passing through the inside and swirl around the central axis 36.

Further, although the stirring unit 33 of the embodiment stirs by swirling the exhaust gas and the cleaning liquid, the stirring unit 33 may stir by a method other than swirling the exhaust gas and the cleaning liquid. For example, the stirring unit 33 may have a member that becomes an obstacle such as a net-like member, and may generate a turbulent flow when the exhaust gas and the cleaning liquid pass through the member, thereby stirring the exhaust gas and the cleaning liquid. ..

Further, although the stirring unit 33 of the embodiment stirs the exhaust gas and the cleaning liquid without driving, the stirring unit 33 may be configured to stir the exhaust gas and the cleaning liquid by driving.

Further, in the embodiment, the exhaust gas washed by the piping device 30 is washed again inside the EGR unit 20. However, if the exhaust gas can be sufficiently removed and desulfurized only by the piping device 30, cleaning inside the EGR unit 20 may be omitted. That is, the EGR unit 20 does not have to have the scrubber nozzle 21.

(Action effect)
As described above, the piping device according to the present embodiment includes an exhaust gas introduction pipe that introduces exhaust gas into the EGR unit, a piping nozzle that injects a cleaning liquid into the exhaust gas introduction pipe, and the inside of the exhaust gas introduction pipe. It is located downstream of the piping nozzle and is provided with a stirring unit that stirs the passing exhaust gas and cleaning liquid.

Therefore, the exhaust gas and the cleaning liquid are agitated in the exhaust gas introduction pipe where the flow velocity is relatively large, and the contact between the exhaust gas and the cleaning liquid is promoted. As a result, the exhaust gas can be effectively dust-removed and desulfurized.

Further, in the piping device according to the present embodiment, the stirring unit has a first swirling member that swirls the exhaust gas and the cleaning liquid in the first swirling direction around the central axis of the exhaust gas introduction pipe.

According to this configuration, since the exhaust gas and the cleaning liquid are swirled by the first swirling member, the exhaust gas and the cleaning liquid can be agitated.

Further, in the piping device according to the present embodiment, the stirring portion is located downstream of the first swivel member, and is around the central axis of the exhaust gas introduction pipe and is opposite to the first swivel direction. It further has a second swivel member that swirls the exhaust gas and the cleaning liquid in the swivel direction.

In this configuration, the exhaust gas and the cleaning liquid are swirled in the first swirling direction by the first swirling member 34 and stirred, and then the exhaust gas and the cleaning liquid are swirled in the second swirling direction opposite to the first swirling direction by the second swirling member 35. It will be swirled and stirred. Therefore, the exhaust gas and the cleaning liquid can be sufficiently agitated in the stirring unit.

Further, at least one of the first swivel member and the second swivel member may be formed with a large number of through holes as a whole.

According to this configuration, since a part of the exhaust gas passes through the through hole, the resistance when the exhaust gas passes through the stirring portion can be suppressed.

10 Engine 20 EGR unit 30 Piping device 31 Exhaust gas introduction piping 32 Piping nozzle 33 Stirring unit 34 First swivel member 35 Second swivel member 36 Central shaft 41 First swivel direction 46 Second swivel direction

Claims (4)

Exhaust gas introduction piping that introduces exhaust gas into the EGR unit,
A piping nozzle that injects cleaning liquid into the exhaust gas introduction pipe,
A piping device that is located inside the exhaust gas introduction pipe and is located downstream of the pipe nozzle, and includes a stirring unit that agitates the passing exhaust gas and cleaning liquid. The piping device according to claim 1, wherein the stirring unit has a first swivel member that swirls the exhaust gas and the cleaning liquid in the first swivel direction around the central axis of the exhaust gas introduction pipe. The stirring unit is located downstream of the first swivel member, and swirls the exhaust gas and the cleaning liquid in the second swirl direction, which is around the central axis of the exhaust gas introduction pipe and is opposite to the first swivel direction. The piping device according to claim 2, further comprising a swivel member. The piping device according to claim 3, wherein at least one of the first swivel member and the second swivel member is formed with a large number of through holes as a whole.

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