WO2012153705A1

WO2012153705A1 - Wet exhaust gas purification device

Info

Publication number: WO2012153705A1
Application number: PCT/JP2012/061668
Authority: WO
Inventors: 隆道細野; 克浩吉澤; 広崇 ▲高▼田; 英和岩▲崎▼; 元彦西村; 正憲東田
Original assignee: 川崎重工業株式会社
Priority date: 2011-05-11
Filing date: 2012-05-07
Publication date: 2012-11-15
Also published as: JP2012237242A

Abstract

　Provided is a wet exhaust gas purification device that enables the simple cleaning/removal of PM accumulated in a demister, enables the use of a low porosity, high collection efficiency demister, and exhibits high exhaust gas purification efficiency. After converting PM that is accumulated inside a demister (50, 51) and that contains an oil component into a low viscosity liquid using heated wash water, the wet exhaust gas purification device sprays the heated wash water so that the wash time and volume of wash water volume required for cleansing/removal are negligible. After cleansing/removal, the demister (50, 51) can be re-used in a state that is almost as good as new. Thus, the pressure drop between the gas stream upstream side and the gas stream downstream side of the demister (50, 51) is increased, the power of a suction blower (7) is increased by the increase in the pressure drop, and the problem of insufficient exhaust suction by the suction blower (7) is avoided.

Description

Wet exhaust gas purification device

The present invention relates to a wet exhaust gas purification device, and more particularly to a wet exhaust gas purification device capable of removing dust such as unburned carbon components and unburned oil in exhaust gas discharged from a diesel engine.

A diesel engine such as a diesel engine is a combustion method in which liquid fuel such as light oil or A heavy oil is directly injected into a combustion chamber, and the evaporated fuel is burned while diffusing into the surrounding air. For this reason, mixing of fuel and air (oxygen) tends to be uneven, and particulate matter dust called particulate matter (hereinafter referred to as “PM”) is generated. In general, diesel engines tend to generate NOx (nitrogen oxides), but if the combustion temperature is lowered to a region where NOx is difficult to generate, the amount of PM emission further increases.

PM includes sulfur oxides produced by the reaction of sulfur in the fuel by combustion, soot produced from parts not in contact with the combustion air when the fuel burns, and fuel adhering to the walls of the combustion chamber, etc. And SOF (Soluble Organic Fraction: unburned portion of fuel and lubricant) etc. are included. These cause serious damage to the respiratory tract and are the most important substances to clean diesel exhaust.

Conventionally, various exhaust gas purification apparatuses that remove and purify dust in exhaust gas (treated gas) have been proposed. As an example, a ceramic porous filter (DPF: Diesel Particulate Filter) is installed in the flue, and dust is filtered and collected, and further, the filter is heated to collect the unburned carbon components and unburned oil components. 2. Description of the Related Art An exhaust gas purifying apparatus that burns and removes such dust is known (for example, see Patent Document 1).

As another example, dust contained in the gas to be treated is captured by bringing the gas to be treated introduced into the apparatus into contact with, for example, mist (mist) water sprayed from a spray nozzle. Also known is a wet exhaust gas purifier that passes a mixed atmosphere of gas and mist liquid through a demister to separate droplets and discharges the purified processing gas out of the system by a suction blower (for example, patents) (See Reference 2 and Patent Reference 3.)

JP 2004-162626 A JP 2006-231170 A Japanese Utility Model Publication No. 7-013420

The exhaust gas purification device disclosed in Patent Document 1 has a low collection efficiency of fine dust having a particle size of several μm or less, such as PM in exhaust gas discharged from a diesel engine, and a large amount of dust. In some cases, the filter is likely to be clogged.

The wet exhaust gas purification device disclosed in Patent Document 2 includes a demister and a filter that remove oil mist in the gas to be treated discharged from the kitchen space, and deposits adhered to the demister and the filter are heated by heating means. Wash with heated cleaning solution.

Also, the wet exhaust gas purification device disclosed in Patent Document 3 cleans dust adhering to the scrubber with the cleaning water supplied from the water pump. Since the demister cleaning water uses the stored water in the apparatus, it is not necessary to supply the cleaning water from another system.

In the conventional wet exhaust gas purification apparatus, when diesel exhaust gas is treated as the gas to be treated, the following problems may occur. When the mixed atmosphere of gas and mist liquid passes through the demister, the droplets can be separated. However, since the PM is trapped in the droplet, a part of the PM that does not drop together with the droplet remains in the demister. Also, since the PM contained in diesel exhaust gas has a very small particle size of several μm or less, even if the treated water is sprayed in the device, the PM rides on the gas flow and easily bypasses the spray droplets of the treated water Therefore, PM that is not captured due to inertial collision with the droplet adheres to the demister.

When PM adheres to the demister, the gap of the demister gradually narrows with time, and the speed of the exhaust gas passing through the demister decreases. This speed reduction causes a vicious cycle in which PM accumulates further, the pressure difference (pressure loss) between the gas flow upstream side and the gas flow downstream side of the demister increases, and the power of the suction blower increases.

Furthermore, when PM accumulation in the demister increases, clogging occurs and the suction blower falls into exhaust gas suction. The problem of clogging of the demister occurs earlier as the demister having a higher collection efficiency (a demister having a lower porosity).

For this reason, the conventional wet exhaust gas purifying apparatus sprays cleaning water from the top and bottom of the demister by means of a spray nozzle to clean and remove PM accumulated in the demister. However, since the PM deposit that closes the gap of the demister contains unburned fuel and lubricating oil, the deposit is very viscous and has low wettability with respect to the washing water. .

However, it is difficult to completely clean and remove the PM accumulated in the demister (cleaning and removing the demister to the state before use) by the conventional cleaning method in which the cleaning water is simply sprayed. In addition, it takes time for washing and consumes a large amount of washing water.

As described above, in the conventional wet exhaust gas purification device, it is difficult to completely clean and remove the PM deposited on the demister, and therefore it is not possible to use a demister with a high collection efficiency (a demister with a low porosity). There has been a problem that a wet exhaust gas purification device with high exhaust gas purification efficiency cannot be provided.

Accordingly, the present invention provides a wet exhaust gas purification device that can easily clean and remove PM deposited on a demister and that can use a demister with a high collection efficiency and a high exhaust gas purification efficiency. With the goal.

The wet exhaust gas purifying apparatus of the present invention is a dust containing liquid treatment means for storing a treatment liquid, a treatment liquid stored in the liquid storage means, and an exhaust gas discharged from a combustion apparatus in gas-liquid contact. Gas-liquid contact means that absorbs and captures the liquid in the processing liquid, and gas-liquid separation means that is disposed downstream of the gas-liquid contact means and separates the liquid from the exhaust gas after processing including the processing liquid that has captured dust. It is a wet exhaust gas purification device. This wet exhaust gas purification apparatus has a cleaning means for injecting a cleaning liquid to the gas-liquid separation means and removing dust adhering to the gas-liquid separation means, and a cleaning liquid heating means for heating the cleaning liquid.

According to the present invention, PM deposited on the demister can be easily cleaned and removed. For this reason, it becomes possible to use the demister of the porosity with high collection efficiency, and can provide the wet exhaust gas purification apparatus with high purification efficiency of exhaust gas.

1 is an overall configuration diagram showing an exhaust gas purification system according to an embodiment of the present invention. It is a schematic block diagram which shows the wet exhaust gas purification apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the modification of the wet exhaust gas purification apparatus which concerns on embodiment of this invention.

Hereinafter, a wet exhaust gas purification apparatus (hereinafter referred to as “scrubber”) according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the following embodiments, a scrubber suitable for removing dust in exhaust gas discharged from a combustion apparatus of a diesel engine mainly for ships, land-traveling vehicles, and stationary on land will be described. The present invention can be similarly applied to a scrubber that removes dust in exhaust gas discharged from a combustion apparatus such as an industrial boiler or a gasification furnace.

In the following description, terms and directions (for example, “upper part”, “lower part”, etc.) are used for convenience, but these are for the purpose of facilitating the understanding of the invention. The technical scope of the invention is not limited. Further, the following description is merely an example of one embodiment of the present invention, and is not intended to limit the present invention, its application, or its use.

Note that “liquid” in the gas-liquid separation in the following embodiment means that the liquid is finally removed from the fluid in a liquid state, and is included in the fluid before removal. It is not always necessary to be in a “liquid” state. “Liquid” in gas-liquid separation includes all particles that are suspended in the air but are not in the form of a single gas molecule. The term “demister” is used to perform gas-liquid separation, but the concept of “demister” of the present invention includes what is called a “mist separator”.

As shown in FIG. 1, reference numeral 1 denotes a diesel engine, and in this embodiment, a marine two-cycle diesel engine. The diesel engine 1 has a water cooling jacket (not shown) in a cylinder head, a side wall portion, and the like, and the cooling water flows through the water cooling jacket to cool the portion to a predetermined temperature.

A first pipe 100 is connected to the exhaust pipe 10 of the diesel engine 1, and a second pipe 110 is connected to the intake pipe 11. As shown in the figure, the diesel engine 1 is provided with a supercharger 2. The supercharger 2 is configured by connecting a turbine rotor 20 and a compressor impeller 21 by a shaft body 22. The turbine rotor 20 is connected to the first pipe line 100 (exhaust side), and the compressor impeller 21 is connected to the second pipe line 110 (intake side).

By supplying the exhaust gas of the diesel engine 1 to the turbine rotor 20, the heat energy of the exhaust gas is converted into rotational energy, and the compressor impeller 21 connected to the turbine rotor 20 rotates to air (fluid containing oxygen). From the atmosphere. The air compressed by the compressor impeller 21 of the supercharger 2 is cooled by the air cooler 3 and then supplied to the combustion chamber of the diesel engine 1. By the action of the supercharger 2, the filling rate of the combustion chamber of the diesel engine 1 is increased, and the output of the diesel engine 1 is increased.

As a means for suppressing the amount of NOx generated from the diesel engine 1, exhaust gas recirculation (EGR) for introducing a part of the combustion exhaust gas to the intake side is used. As shown in the figure, the diesel engine 1 to which EGR is applied has a third pipeline 120 connected so as to bypass the first pipeline 100 and the second pipeline 110. In the third pipe line 120, the scrubber 4 that captures PM contained in the exhaust gas of the diesel engine 1 in contact with the treated water in order from the upstream side of the gas flow, and the suction that sucks the treated gas purified by the scrubber 4 A blower 7 and a gas cooler 8 for cooling the processing gas are connected, and a part of the exhaust gas of the diesel engine 1 (for example, an exhaust gas amount corresponding to 30% of the total exhaust gas amount) is returned to the second pipe 110. And recirculated to the diesel engine 1. The scrubber 4 can capture SOx (sulfur oxide) by bringing the exhaust gas into contact with the treated water.

Next, the scrubber 4 of the present embodiment will be described with reference to FIG. The scrubber 4 is formed in a vertical cylindrical shape, and includes a lower casing 4a and an upper casing 4b provided on the upper portion of the lower casing 4a.

At the bottom of the lower casing 4a, a liquid storage part 41 for storing the processed water (process liquid) 40 is formed. The liquid storage unit 41 is provided with a heater 42 for heating the treated water 40 to a predetermined temperature, and the outside of the lower casing 4a is externally covered with a heat insulating material such as glass wool, so that the treated water 40 is heated to 60 ° C., for example. It is supposed to be retained.

Connected to the side wall of the lower casing 4a above the liquid storage section 41 is a treated gas introduction pipe 43 for introducing exhaust gas of the diesel engine 1 (hereinafter referred to as “treated gas”) into the scrubber 4. Has been.

A spray nozzle 44 as gas-liquid contact means for spraying mist-like treated water 40 downward with respect to the gas to be treated introduced into the scrubber 4 is disposed above the liquid reservoir 41. A circulation pipe 451 having a circulation pump 45 for transferring the treated water 40 in the liquid reservoir 41 is connected to the spray nozzle 44. The treated water 40 sprayed from the spray nozzle 44 is once collected in the liquid storage unit 41, transferred through a circulation pipe 451, and forms a circulation line for spraying from the spray nozzle 44 again. As illustrated, impurities are removed from the treated water 40 transferred to the spray nozzle 44 by a filter 452. The flow rate of the treated water 40 sprayed from the spray nozzle 44 can be changed as appropriate by adjusting the opening of the valve 453.

In the present embodiment, the mist-like treated water 40 sprayed from the spray nozzle 44 is brought into contact with the gas to be treated. Instead, the treated water 40 in the liquid storage unit 41 is bubbled so that the gas and mist It is also possible to create a mixed atmosphere with the liquid and to bring it into contact with the gas to be processed.

A processing gas discharge pipe 46 for discharging the processing gas purified by the scrubber 4 is connected to the upper part of the upper casing 4b.

In the upper casing 4 b, two demisters as gas-liquid separation means are arranged along the gas flow path 47. The demisters are a demister 50 and a demister 51 from the gas flow upstream toward the gas flow downstream. The demister 50 on the upstream side of the gas flow and the demister 51 on the downstream side of the gas flow are arranged with a predetermined distance. The number of demisters can be changed as appropriate according to the amount of gas to be processed in the scrubber 4 and the properties of the gas to be processed.

The

demisters

50 and 51 are structures in which flexible metal strands are entangled with each other to form a corrugated shape, and disk-like members are overlapped so that the corrugated shape is alternated. The

demisters

50 and 51 have a function of separating the liquid droplets by passing the mixed atmosphere of the gas sent from the lower casing 4 a and the mist-like liquid through the

demisters

50 and 51.

Here, the void ratio in the demister 50 and the void ratio in the demister 51 may be substantially the same. However, since the demister 50 on the upstream side of the gas flow may be easily clogged, the demister 50 on the upstream side of the gas flow may be clogged. It is preferable to set the porosity higher than the porosity of the demister 51 on the downstream side of the gas flow. The “porosity” in the demister 50 (51) is, for example, the roughness of the lattice of a metal wire, and the coarser the mesh, the higher the porosity.

As shown in the drawing,

pressure gauges

520 and 521 are connected to the side wall of the upper casing 4b in order to check whether or not clogging has occurred inside the

demisters

50 and 51. The pressure gauges 520 and 521 measure the pressure difference (pressure loss) between the gas flow upstream side and the gas flow downstream side of each

demister

50 and 51.

In the vicinity of the

demisters

50 and 51, a cleaning spray nozzle (cleaning means) for cleaning the

demisters

50 and 51 is provided. Specifically, four cleaning spray nozzles 53aa spraying cleaning water (cleaning liquid) upward from the vicinity of the gas flow toward the demister 50, and cleaning water spraying downward from the vicinity of the gas flow toward the demister 50. Four cleaning spray nozzles 53ab are arranged.

Between the demister 50 and the demister 51, in the vicinity of the upstream of the gas flow of the demister 51, four cleaning spray nozzles 53 ba for spraying cleaning water upward toward the demister 51 are arranged. Four cleaning spray nozzles 53bb for spraying cleaning water downward toward the demister 51 are disposed in the vicinity of the downstream.

The cleaning spray nozzles 53aa and 53ab and the cleaning spray nozzles 53ba and 53bb are connected to the branch pipe 54, respectively. Each branch pipe 54 is connected to a branch pipe 55 having

valves

550 and 551, and these are connected to a hot water heater 60 that is a cleaning liquid heating means via a hot water supply pipe 56. In addition, a valve is provided in each branch pipe 54, and both of the spray nozzles 53aa and 53ab (53ba and 53bb) are used at the same time by independently controlling the opening and closing of these valves. A configuration that can be used is also possible. The water heater 60 is set so that the washing water becomes, for example, warm water of 60 ° C. Thereby, the washing water heated from the washing spray nozzles 53aa, 53ab, 53ba, 53bb is sprayed.

FIG. 3 is a modification of the scrubber 4 of the present embodiment. In this modification, two cleaning spray nozzles 53ba spraying upward cleaning water (cleaning liquid) from the vicinity of the gas flow upstream toward the central region 51a of the demister 51, and upward cleaning water toward the outer peripheral region 51b of the demister 51. Two cleaning spray nozzles 53bb for spraying are disposed. Further, in the vicinity of the gas flow downstream of the demister 51, two cleaning spray nozzles 53ca spraying downward cleaning water toward the central region 51a of the demister 51, and downward cleaning water toward the outer peripheral region 51b of the demister 51. Two cleaning spray nozzles 53cb for spraying are disposed.

The branch pipe L1 connecting each of the cleaning spray nozzles 53ba and 53bb is provided with valves V1 and V2, and the opening and closing of these valves V1 and V2 are controlled independently to thereby control the spray nozzles 53ba and 53bb. Both can be used at the same time, or either one can be selected and used. The branch pipe L1 connecting the cleaning spray nozzles 53ca and 53cb is also provided with valves V3 and V4. Similarly, both the spray nozzles 55ba and 55bb can be used at the same time, or one of them can be selected and used. . Thereby, even if the scrubber 4 is in operation, the demister 51 can be cleaned without sealing the demister 51 with cleaning water.

The number of spray nozzles can be changed as appropriate according to the amount of gas to be processed in the scrubber 4, the sizes of the scrubber 4 and the demisters 50 and 51, the desired cleaning range, and the like.

In the present embodiment, an example is described in which cleaning water heated by the hot water heater 60 is made and supplied to the cleaning spray nozzles 53aa and 53ab and the cleaning spray nozzles 53ba and 53bb. Instead, the heated washing water may be obtained by exchanging heat with another heat medium. Specifically, as shown in FIG. 2, for example, a heat exchanger 65 for recovering the sensible heat of exhaust gas from the diesel engine 1 is separately provided, and the normal temperature wash water supplied from the wash water supply source 70 is used as the heat exchanger. The cleaning water heated to about 60 ° C. by supplying to 65 may be produced and supplied to the cleaning spray nozzles 53aa and 53ab and the cleaning spray nozzles 53ba and 53bb. In this case, the heat exchanger 65 may recover the sensible heat of the cooling water (about 80 to 90 ° C.) of the diesel engine 1 instead of the one that recovers the exhaust gas sensible heat of the diesel engine 1.

Further, as shown in the drawing, a pipe 67 having a valve 671 is branched from the circulation pipe 451 and the pipe 67 is connected to the hot water supply pipe 56, and the treated water 40 at about 60 ° C. stored in the liquid storage section 41 is supplied. The cleaning spray nozzles 53aa and 53ab and the cleaning spray nozzles 53ba and 53bb may be supplied.

Next, the operation of the scrubber 4 configured as described above will be described with reference to FIGS. As shown in FIG. 1, first, when the diesel engine 1 is started, the exhaust gas discharged from the diesel engine 1 is statically pressured in the exhaust pipe 10 and guided to the supercharger 2 through the first pipe 100. .

In the supercharger 2, the heat energy of the exhaust gas is converted into rotational energy, and the compressor impeller 21 connected to the turbine rotor 20 rotates to suck air (fluid containing oxygen) from the atmosphere. The air compressed by the compressor impeller 21 of the supercharger 2 is cooled by the air cooler 3 and then supplied to the combustion chamber of the diesel engine 1. On the other hand, the exhaust gas discharged from the supercharger 2 is diffused into the atmosphere through an exhaust silencer (not shown).

On the other hand, a part of the exhaust gas from the diesel engine 1 (for example, the exhaust gas amount corresponding to 30% of the total exhaust gas amount) is introduced into the scrubber 4 through the third pipe line 120 as the gas to be treated. The scrubber 4 captures PM contained in the gas to be treated by bringing the water to be treated into contact with the gas to be treated. The processing of the gas to be processed by the scrubber 4 will be described later with reference to FIG. The processing gas purified by the scrubber 4 is discharged by the suction blower 7, cooled to a predetermined temperature by the gas cooler 8, and recirculated to the diesel engine 1 through the second pipe 110.

As shown in FIG. 2, the gas to be treated introduced into the scrubber 4 is in countercurrent contact with the mist-like treated water 40 (about 60 ° C.) sprayed from the spray nozzle 44. Thereby, the PM contained in the gas to be treated is absorbed in the treated water 40 and captured. Thereafter, the mixed atmosphere of the gas and the mist-like liquid (treated water 40) is sent along the gas flow path 47 to

demisters

50 and 51 as gas-liquid separation means in the upper casing 4b. The mixed atmosphere of the gas sent from the lower casing 4a and the mist-like liquid passes through the

demisters

50 and 51, so that the liquid droplets are separated, and the liquid droplets are collected in the liquid storage part 41 in the lower casing 4a. Is done. On the other hand, the processing gas purified by passing through the

demisters

50 and 51 is discharged by a suction blower (not shown).

As described in the description of [Background Art], when the mixed atmosphere of gas and mist-like liquid passes through the

demisters

50 and 51, the droplets are separated by the demisters 50 and 51. However, since PM is trapped in the droplets, some PM that does not drop together with the droplets remains in the

demisters

50 and 51. Also, since the PM contained in diesel exhaust gas has a very small particle size of several μm or less, even if the treated water is sprayed in the device, the PM rides on the gas flow and easily bypasses the spray droplets of the treated water Therefore, PM that is not captured due to inertial collision with the droplet adheres to the demister.

When PM adheres to the

demisters

50 and 51, the gaps of the

demisters

50 and 51 gradually narrow with time, and the speed of the exhaust gas passing through the

demisters

50 and 51 decreases. This speed reduction causes a vicious cycle in which PM accumulates further, the pressure difference (pressure loss) between the gas flow upstream side and the gas flow downstream side of the

demisters

50 and 51 increases, and the power of the suction blower (not shown) Increases and the exhaust gas purification efficiency of the scrubber 4 decreases.

In order to avoid the operation stop of the scrubber 4 due to clogging of the

demisters

50 and 51, the pressure difference (pressure loss) between the gas flow upstream side and the gas flow downstream side of each

demister

50 and 51 is measured during the operation of the scrubber 4. It is preferable to monitor the indicated values of the pressure gauges 520 and 521 constantly or at regular intervals.

When the indicated value shows a predetermined value or more during operation, there is a high probability that the corresponding demister 50 (51) is clogged. In the description of this operation, it is assumed that the demister 50 is clogged. In this case, first, the water heater 60 is activated. Then, the valve 550 of the branch pipe 55 communicating with the cleaning spray nozzles 53aa and 53ab is opened, and the cleaning water heated to about 60 ° C. with respect to the demister 50 from the gas flow upstream side and the gas flow downstream side of the demister 50. Spray.

The spray of cleaning water on the demister 50 (51) may be continuous spraying. However, when the cleaning water is sprayed on the entire area of the demister 50 (51) as in the present embodiment, the water film of the cleaning water becomes the demister 50 (51). There is a possibility that the pressure difference (pressure loss) between the gas flow upstream side and the gas flow downstream side of the demister increases during cleaning. In such a case, as described in the modification of FIG. 3, each cleaning spray nozzle may be divided into partial regions, and a valve may be provided for each region so that the cleaning water is not sprayed on the entire surface of the demister.

When the PM containing oil accumulated in the demister 50 comes into contact with the heated cleaning water, the PM deposit is warmed. As a result, the deposit containing oil begins to drip in the form of a heated low-viscosity liquid, and the PM deposit that has become liquid is easily washed away by the jet of cleaning water. In this case, since the PM containing oil accumulated in the demister 50 starts to drip in the form of a low-viscosity liquid by the heated washing water, the deposit is completely washed and removed. The cleaning time and cleaning water required are very small.

When the PM containing the oil accumulated in the demister 50 is almost completely cleaned and removed, the valve 550 of the branch pipe 55 is closed to stop the supply of the cleaning water to the cleaning spray nozzles 53aa and 53ab. It should be noted that the same procedure as described above is performed when the PM containing oil accumulated in the demister 51 is cleaned and removed.

For cleaning and removal of PM containing oil accumulated in the demister 50 (51), cleaning water or liquid heated by sensible heat of exhaust gas or cooling water (about 80 to 90 ° C) of the diesel engine 1 is used. Similarly, even when the treated water 40 of about 60 ° C. stored in the storage part 41 is used, the PM containing the oil accumulated in the demister 50 (51) is almost completely cleaned in a short time.・ Can be removed.

In addition, the measurement of the pressure loss between the gas flow upstream side and the gas flow downstream side of each demister 50 (51) described above, determination of clogging of the demister 50 (51), and spraying of the heated washing water are as follows: For example, the control means (not shown) of the scrubber 4 takes pressure measurement data and determines whether the demister 50 (51) is clogged, and then the heated cleaning water. The spray control may be executed.

The spray of the cleaning water by the cleaning spray nozzles 53aa and 53ab (53ba and 53bb) may be sprayed simultaneously from the vertical direction to the demister 50 (51) as in the present embodiment. For example, the spray nozzle 53aa , 53ab (53ba, 53bb) may be added one by one, and either one of the upper direction and the lower direction may be selected and sprayed with cleaning water. Moreover, these spraying times may overlap each other or may not overlap each other.

As described above, according to the scrubber 4 of the present embodiment, the PM containing the oil accumulated in the demister 50 (51) is made into a low-viscosity liquid with the heated washing water, and then heated. Since the washed water is sprayed, the washing time and amount of washing water required for washing / removal are very small. After being cleaned and removed, the demister 50 (51) can be reused in a state almost similar to a new one.

Since the demister 50 (51) that has been cleaned and removed as described above can be reused in a state almost similar to a new one, a pressure difference (pressure) between the gas flow upstream side and the gas flow downstream side of the demister 50 (51). Loss), the power of the suction blower 7 due to an increase in pressure loss, and the problem that the suction blower 7 falls short of exhaust gas suction can be avoided. Further, even when a part of the exhaust gas of the diesel engine 1 (for example, the exhaust gas amount corresponding to 30% of the total exhaust gas amount) is recirculated to the diesel engine 1 as in the present embodiment, the exhaust gas recirculation is performed. There is no shortage of volume.

Conventionally, a demister with a low porosity (high collection efficiency) was clogged early and difficult to use, but in the present embodiment, it contains oil accumulated in the demister 50 (51). Since PM can be easily cleaned and removed, one having a low porosity (high collection efficiency) can be used. Thereby, the dust removal performance of the scrubber 4 is improved. Since the dust removal performance of the scrubber 4 is improved, the dust mixed in the suction blower 7, the gas cooler 8, and the diesel engine 1 connected thereto can be extremely reduced. As a result, the maintenance of those facilities becomes easy and the lifetime can be extended.

The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the scope of the claims rather than the scope described above, and includes all modifications within the scope and meaning equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Supercharger 3 Air cooler 4 Scrubber

4a Lower casing

4b Upper casing 7 Suction blower 8 Gas cooler 40 Treated water 41 Liquid storage part 44 Spray nozzle 47

Gas flow path

50, 51 Demister 53aa, 53ab, 53ba, 53bb Cleaning spray nozzle

Claims

A liquid storage means for storing the processing liquid;
Gas-liquid contact means for bringing the treatment liquid stored in the liquid storage means into contact with the exhaust gas discharged from the combustion apparatus in gas-liquid contact, and absorbing and capturing the dust contained in the exhaust gas in the treatment liquid;
A wet exhaust gas purifier having gas-liquid separation means that is disposed downstream of the gas-liquid contact means and separates liquid from the treated exhaust gas containing the treatment liquid capturing the dust,
Cleaning means for injecting a cleaning liquid onto the gas-liquid separating means and removing the dust adhering to the gas-liquid separating means;
A wet exhaust gas purifier having a cleaning liquid heating means for heating the cleaning liquid.
The cleaning liquid heating means is a heat exchanger for obtaining a heated cleaning liquid by exchanging heat with a heat medium, wherein the heat medium cools the combustion exhaust gas discharged from the combustion apparatus or the combustion apparatus The wet exhaust gas purification apparatus according to claim 1, wherein the wet exhaust gas purification apparatus is cooling water.
The combustion device is a diesel engine;
The wet exhaust gas purifying apparatus according to claim 1 or 2, wherein the exhaust gas is exhaust gas discharged from the diesel engine, and the dust contained in the exhaust gas is a particulate matter.