JP5789321B2 - Scrubber and engine system - Google Patents

Description

  The present invention relates to a scrubber (wet gas cleaning apparatus) that cleans exhaust gas discharged from an engine, and an engine system including the scrubber.

  As a technique for reducing the amount of nitrogen oxide (NOx) discharged from the engine, exhaust gas recirculation (EGR) for returning a part of the exhaust gas to the engine is known. By returning a part of the exhaust gas to the engine, combustion is performed in a state where the oxygen concentration is low. As a result, the combustion temperature is lowered and the generation of NOx is suppressed. However, depending on the fuel used, the exhaust gas may contain a large amount of particulate matter (PM) or sulfur oxide (SOx). In this case, PM or SOx is removed from the exhaust gas to be recirculated. It needs to be removed. In order to remove PM and SOx from the exhaust gas, a scrubber using a cleaning liquid is effective (see reference numeral 15 in FIG. 2 of Patent Document 1).

  Further, from the viewpoint of environmental protection, it is desirable to remove PM and SOx not only for exhaust gas (EGR gas) returned to the engine but also for exhaust gas discharged to the atmosphere. Also in this case, a scrubber using a cleaning liquid is effective for removing PM and SOx from the exhaust gas.

  In order to remove SOx (perform desulfurization), a desulfurization neutralizing agent (an alkaline solvent such as caustic soda) is added to the cleaning liquid used in the scrubber, and the pH value of the cleaning liquid is adjusted to a certain level or more. However, since the pH value decreases when the cleaning liquid comes into contact with the exhaust gas, when the cleaning liquid is used repeatedly, it is necessary to continuously add a neutralizing agent to maintain the pH value of the cleaning liquid. Further, when the cleaning liquid is discharged to the outside, if there is a pH value discharge restriction, it is necessary to adjust the pH value of the cleaning liquid so that the discharge restriction can be cleared. Considering maintenance of such desulfurization performance and compliance with emission regulations, it is safe to add more neutralizing agent, but there is also a demand to reduce the amount of neutralizing agent used.

JP 2011-157959 A

  The present invention has been made in view of the circumstances as described above, and while maintaining a sufficient desulfurization performance while suppressing the amount of the neutralizing agent introduced into the cleaning liquid, it is also possible to clear the discharge regulation of the cleaning liquid. It aims to provide a scrubber that can be used.

  A scrubber according to an embodiment of the present invention is a scrubber that cleans exhaust gas discharged from an engine, and collects and collects an injection nozzle that injects a cleaning liquid into the exhaust gas, and a cleaning liquid injected from the injection nozzle. In addition, a reservoir portion for discharging a part of the collected cleaning liquid to the outside, a circulation pipe for supplying the cleaning liquid stored in the reservoir section to the injection nozzle, and a neutralizing agent are introduced into the flow path of the circulation pipe And a control device for determining an amount of the neutralizing agent to be charged from the neutralizing agent charging device, wherein the control device has a predetermined pH value of the cleaning liquid sprayed from the spray nozzle and a predetermined value. The neutralizing agent to be charged from the neutralizing agent charging device based on the deviation from the target injection pH value and the deviation between the pH value of the cleaning liquid stored in the water reservoir and the predetermined target water pH value To determine the amount of input It has been made.

  In such a configuration, it is possible to adjust the pH value of the cleaning liquid sprayed from the spray nozzle by directly introducing the neutralizing agent into the cleaning liquid sprayed from the spray nozzle. Therefore, when the amount of the neutralizing agent to be charged is determined by the deviation between the pH value of the cleaning liquid jetted from the jet nozzle and the predetermined target jetting pH value, the pH value of the cleaning liquid stored in the reservoir is unnecessarily increased. The amount of neutralizing agent input can be suppressed. Furthermore, the amount of the neutralizing agent to be introduced is determined by the deviation between the pH value of the cleaning liquid sprayed from the spray nozzle and the predetermined target injection pH value, and the pH value of the cleaning liquid stored in the water reservoir and the predetermined target stored water pH. Since it is determined based on the deviation from the value, it is possible to maintain sufficient desulfurization performance (target injection pH value) and clear the cleaning liquid discharge regulation (target stored water pH value).

  In the scrubber, the exhaust gas may be EGR gas returned to the engine. According to such a configuration, since the purified EGR gas is returned to the engine, the risk of corroding the engine can be reduced.

  Further, in the scrubber, the control device is configured to set the target injection pH value based on a sulfur content of fuel used for the engine and a flow rate of exhaust gas passing through the scrubber. May be.

  According to such a configuration, the target injection pH value can be set to an appropriate value, so that the target injection pH value can be prevented from becoming excessively large, and as a result, the amount of neutralizing agent introduced into the cleaning liquid is suppressed. be able to.

  In the scrubber, the control device may be configured to set a predetermined fixed value as the target stored water pH value.

  According to such a configuration, the discharge restriction of the cleaning liquid can be surely cleared by setting the pH value determined by the discharge restriction as the target stored water pH value.

  Further, in the above scrubber, the control device is predicted to be necessary for maintaining the desulfurization performance based on the sulfur content of the fuel used in the engine and the flow rate of the exhaust gas passing through the scrubber. The amount of basic neutralizing agent input, which is the amount of summing agent, is calculated, the difference between the pH value of the cleaning liquid sprayed from the spray nozzle and the predetermined target spray pH value, the pH value of the cleaning liquid stored in the water reservoir And the amount of the neutralizing agent to be charged by the neutralizing agent charging device may be determined based on the deviation between the pH value and the predetermined target stored water pH value and the basic neutralizing agent charging amount. Good.

  According to this configuration, so-called feed-forward control using the basic neutralizer input amount can be performed for the input amount of the neutralizer supplied by the neutralizer input device. Therefore, even if the operating condition of the engine changes, the amount of neutralizing agent can be quickly adjusted to an appropriate value.

  Moreover, the engine system which concerns on a certain form of this invention is equipped with said scrubber.

  As described above, according to the above scrubber, it is possible to maintain sufficient desulfurization performance and suppress the cleaning liquid discharge regulation while suppressing the amount of the neutralizing agent to be supplied to the cleaning liquid.

FIG. 1 is a block diagram of an engine system according to the first embodiment. FIG. 2 is a schematic view of the scrubber according to the first embodiment. FIG. 3 is a block diagram of a scrubber control system according to the first embodiment. FIG. 4 is a flowchart showing a method for controlling the amount of neutralizing agent input. FIG. 5 is a graph showing the relationship between the EGR gas flow rate and the basic neutralizing agent input amount. FIG. 6 is a graph showing the relationship between the EGR gas flow rate and the target injection pH value. FIG. 7 is a flowchart showing a method for controlling the amount of neutralizing agent input according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Below, the same code | symbol is attached | subjected to the element which is the same or it corresponds through all the drawings, and the overlapping description is abbreviate | omitted.

(First embodiment)
First, a first embodiment of the present invention will be described. In the following, the case of cleaning the EGR gas returned to the engine in the exhaust gas will be described, but the same can be considered for cleaning the exhaust gas discharged to the atmosphere.

<Overall configuration of engine system>
First, the overall configuration of the engine system 100 according to the present embodiment will be described. FIG. 1 is a block diagram of the engine system 100. As shown in FIG. 1, the engine system 100 includes an engine 10, a supercharger 20, an EGR blower 30, a scrubber 40, and a wastewater treatment device 60.

  The engine 10 in the present embodiment is a main propulsion machine for a ship and is a large two-stroke diesel engine. The engine 10 is supplied with scavenging gas (“charged gas” in the case of a four-stroke engine) from the supercharger 20 through the scavenging flow path 11. Further, the exhaust gas discharged from the engine 10 is supplied to the supercharger 20 through the exhaust passage 12. The engine 10 may be a 4-stroke engine, a gas engine, or a gasoline engine. Further, the engine 10 is not limited to that used for ships, but may be used for power generation equipment.

  The supercharger 20 is a device that boosts air and supplies it to the engine 10. The supercharger 20 has a turbine part 21 and a compressor part 22. Exhaust gas discharged from the engine 10 is supplied to the turbine unit 21, and the turbine unit 21 is rotated by the energy of the exhaust gas. The turbine part 21 and the compressor part 22 are connected by a connecting shaft 23, and the compressor part 22 also rotates as the turbine part 21 rotates. When the compressor unit 22 rotates, the air (atmosphere) taken from the outside is pressurized, and the pressurized air is supplied to the engine 10 via the scavenging flow path 11.

  The EGR blower 30 is provided in an EGR flow path 31 that connects the exhaust flow path 12 and the scavenging flow path 11, and extracts a part of the exhaust gas in the exhaust flow path 12 (hereinafter referred to as exhaust gas extracted from the exhaust flow path 12). The gas is referred to as “EGR gas”), and the EGR gas is pressurized and sent to the scavenging flow path 11. The EGR gas sent to the scavenging flow path 11 is mixed with the atmosphere pressurized by the supercharger 20 and supplied to the engine 10 as the scavenging gas. Thereby, the oxygen concentration of the scavenging gas supplied to the engine 10 is reduced, and the amount of NOx emission can be reduced. The structure of the EGR blower 30 is not particularly limited, but a positive displacement type is adopted in this embodiment.

  The scrubber 40 is a device that is provided in the EGR flow path 31 and removes SOx and PM from the EGR gas using a cleaning liquid. In particular, since exhaust gas from a large diesel engine contains a large amount of SOx and PM, it is very effective to install a scrubber in the engine system when performing EGR in a large diesel engine. In addition, since the scrubber 40 of this embodiment has a cooling function for cooling EGR gas as will be described later, a cooling device is not provided in the EGR flow path 31, but a cooling device is provided in the EGR flow path 31. It may be provided. In addition, the detailed configuration of the scrubber 40 will be described later.

  The wastewater treatment device 60 is a device that purifies the cleaning liquid used in the scrubber 40. All or part of the cleaning liquid purified by the wastewater treatment apparatus 60 is discharged to the sea. The problem with the discharge of cleaning liquid into the sea is the regulation of wastewater (cleaning liquid) discharge. The emission regulation includes turbidity emission regulation and pH value emission regulation. The waste water treatment apparatus 60 is for clearing the turbidity discharge regulation among them. Specifically, the cleaning liquid used in the scrubber 40 contains a large amount of particulate matter formed by solidifying PM, and the turbidity is very high. Therefore, for example, using a centrifuge as the wastewater treatment apparatus 60, the dust is separated from the cleaning liquid to reduce the turbidity of the cleaning liquid. Thereby, discharge regulation of turbidity of waste water (cleaning liquid) can be cleared. On the other hand, the pH value discharge regulation is handled by the scrubber 40 as described later. A wastewater pH sensor 61 (see FIG. 2) for confirming the final pH value of the cleaning liquid may be provided downstream of the wastewater treatment apparatus 60.

<Configuration of scrubber>
Next, the detailed configuration of the scrubber 40 will be described. FIG. 2 is a schematic view of the scrubber 40 according to the present embodiment. The thick arrows in the figure indicate the flow of EGR gas. The scrubber 40 according to this embodiment is an integrated scrubber having all of a cleaning function for cleaning EGR gas, a water storage function for storing a cleaning liquid, and a cooling function for cooling the EGR gas. As shown in FIG. 2, the scrubber 40 includes an injection nozzle 41, a water reservoir 42, a circulation pipe 43, and a neutralizing agent charging device 44.

  The injection nozzle 41 is a part that injects the cleaning liquid into the EGR gas. The injection nozzle 41 is provided in the vicinity of the inlet of the scrubber 40 and injects the cleaning liquid into the EGR gas that has just flowed into the scrubber 40. Thus, since the scrubber 40 according to the present embodiment employs an injection type, it is possible to introduce a neutralizing agent into the flow path of the circulation pipe 43.

  The water reservoir 42 is a part that collects and collects the cleaning liquid sprayed from the spray nozzle 41. The water reservoir 42 is located in the lower part of the scrubber 40, and the cleaning liquid sprayed from the spray nozzle 41 falls to the water reservoir 42 by its own weight. The EGR gas injected with the cleaning liquid passes through the cooling unit 45 and is cooled by heat exchange, and the mist cleaning liquid contained in the EGR gas is removed by the mist catcher 46. The condensed water generated in the cooling unit 45 and the cleaning liquid captured by the mist catcher 46 fall to the water storage unit 42 by its own weight. The EGR gas that has passed through the cooling unit 45 and the mist catcher 46 exits the scrubber 40 and flows toward the EGR blower 30 (see FIG. 1).

  The circulation pipe 43 is a member that supplies the cleaning liquid stored in the water reservoir 42 to the spray nozzle 41. A circulation pump 47 is provided in the circulation pipe 43. Further, the circulation pipe 43 has a neutralizing agent charging part 48 for taking in the neutralizing agent charged from the neutralizing agent charging device 44. Further, a stored water pH sensor 49 is provided at a portion upstream of the neutralizing agent charging portion 48 of the circulation pipe 43, and an injection pH sensor 50 is disposed at a portion downstream of the neutralizing agent charging portion 48. Is provided. The stored water pH sensor 49 can measure the pH value of the cleaning liquid stored in the stored water portion 42 (hereinafter referred to as “reserved water pH value”), and the injection pH sensor 50 is injected from the injection nozzle 41. The pH value of the cleaning liquid (hereinafter referred to as “jetting pH value”) can be measured.

  The neutralizer feeding device 44 is a device that feeds the neutralizing agent into the flow path of the circulation pipe 43 through the neutralizer feeding section 48 of the circulation pipe 43. In this embodiment, caustic soda is used as a neutralizing agent. The neutralizing agent feeding device 44 of this embodiment feeds the neutralizing agent into the cleaning liquid flowing through the circulation pipe 43 instead of the cleaning liquid stored in the water reservoir 42. By comprising in this way, it becomes unnecessary to increase the whole washing | cleaning liquid stored in the water storage part 42 to the pH value required for desulfurization. Therefore, the usage-amount of a neutralizing agent can be suppressed.

<Control system configuration>
Next, the configuration of the scrubber control system will be described. FIG. 3 is a block diagram of the configuration of the control system. The scrubber according to the present embodiment has a control device 70. The control device 70 is constituted by a CPU, a ROM, a RAM, and the like. As shown in FIG. 3, the control device 70 is electrically connected to the stored water pH sensor 49, the injection pH sensor 50, and the EGR blower 30. The control device 70 acquires the stored water pH value, the injection pH value, and the EGR gas flow rate (which can be obtained from the number of revolutions of the EGR blower 30) based on signals transmitted from these instruments and devices. The EGR gas flow rate may be acquired based on a signal transmitted from the flow meter provided in the EGR flow path 31.

  The control device 70 is also electrically connected to a driving operation unit 71 provided in a cab of a hull in which the engine system 100 is mounted. The driving operation unit 71 is configured such that the driver can input the sulfur content (mass%) of the fuel used for the engine 10 and can store the value. The control device 70 acquires the sulfur content of the fuel used for the engine 10 based on the signal transmitted from the driving operation unit 71. The operation unit 71 may be configured to be able to select an oil type of fuel used in the engine 10 and to store and transmit a sulfur content corresponding to the oil type.

  Further, the control device 70 is electrically connected to the neutralizing agent charging device 44. The control device 70 performs various calculations based on the acquired stored water pH value, injection pH value, EGR gas flow rate, and sulfur content, and transmits a control signal to the neutralizing agent charging device 44. As a result, the control device 70 controls the amount of neutralizing agent introduced into the flow path of the circulation pipe 43 by the neutralizing agent introduction device 44 (hereinafter referred to as “neutralizing agent input amount”).

<Method for controlling the amount of neutralizing agent input>
Next, a method for controlling the amount of neutralizing agent input will be described. FIG. 4 is a flowchart showing a method of controlling the amount of neutralizing agent input. The calculation and control described below are performed by the control device 70. First, when the processing is started, the control device 70 reads signals transmitted from the accumulated water pH sensor 49, the injection pH sensor 50, the EGR blower 30, and the operation operation unit 71, and the accumulated water is based on these signals. Various information such as pH value, injection pH value, EGR gas flow rate, and sulfur content is acquired (step S1).

Subsequently, the control device 70 calculates the basic neutralizing agent input amount based on the EGR gas flow rate and the sulfur content (step S2). The basic neutralizing agent input is a neutralizing agent input predicted to be necessary to maintain the desulfurization performance. The control device 70 has map data corresponding to the graph as shown in FIG. 5, and calculates the basic neutralizing agent input amount from this map data. FIG. 5 shows the relationship between the EGR gas flow rate and the basic neutralizing agent input amount for each sulfur content. For example, in FIG. 5, a sulfur content of 2.0%, EGR gas flow rate if _{Q 1,} the basic neutralizing charged amount is _{W 1.} The amount of basic neutralizing agent input increases as the sulfur content increases and as the EGR gas flow rate increases. Note that FIG. 5 is a conceptual diagram and does not necessarily match an actual value (the same applies to FIG. 6).

Subsequently, the control device 70 sets a target injection pH value based on the EGR gas flow rate and the sulfur content (step S3). The control device 70 has map data corresponding to the graph as shown in FIG. 6, and acquires the target injection pH value from this map data. FIG. 6 shows the relationship between the EGR gas flow rate and the target injection pH value for each sulfur content. For example, in FIG. 6, a sulfur content of 2.0%, EGR gas flow rate if _{Q 1,} target injection pH value is PH _1. The target injection pH value increases as the sulfur content increases and as the EGR gas flow rate increases.

  Subsequently, the control device 70 sets a target stored water pH value (step S4). The target stored water pH value is a predetermined fixed value. From the viewpoint of environmental protection, wastewater (cleaning solution) cannot be discharged to the outside (the sea) unless the pH value is within a specified range. In the present embodiment, a value slightly larger than the lower limit value of the specified range is set as the target stored water pH value. For example, when the lower limit value of the specified range is 6.5, the control device 70 sets the target stored water pH value to “6.8”.

  Subsequently, the control device 70 calculates an injection side correction value based on the deviation between the injection pH value and the target injection pH value (step S5). Specifically, the injection side correction value is calculated so that the difference (deviation) between the injection pH value and the target injection pH value is eliminated. Thus, step S5 corresponds to feedback control for the injection pH value. PID control can be adopted as this feedback control. The injection side correction value is for correcting the basic neutralizing agent input amount described above.

  Subsequently, the control device 70 calculates a stored water side correction value based on the deviation between the stored water pH value and the target stored water pH value (step S6). Specifically, a stored water side correction value is calculated so that the difference (deviation) between the stored water pH value and the target stored water pH value is eliminated. Thus, Step S6 corresponds to feedback control for the stored water pH value. PID control can be adopted as this feedback control. The stored water side correction value is for correcting the basic neutralizing agent input amount described above.

  Subsequently, the control device 70 determines the neutralizing agent input amount based on the basic neutralizing agent input amount, the injection side correction value, and the stored water side correction value (step S7). Specifically, the larger value (which may be negative) of the injection side correction value and the stored water side correction value (which may be negative) is added to the basic neutralizer input amount, The value is taken as the amount of neutralizing agent input. As described above, in the control of the neutralizing agent input amount of the present embodiment, the basic neutralizing agent input amount is determined by the foot forward control, and the neutralizing agent input amount is finely adjusted by the feedback control so as to satisfy the target pH value. doing.

  Subsequently, the control device 70 transmits a control signal to the neutralizing agent charging device 44 so that the neutralizing agent charging amount from the neutralizing agent charging device 44 becomes the neutralizing agent charging amount calculated in step S7. (Step S8). As a result, an appropriate amount of neutralizing agent is added to the cleaning liquid. When step S8 ends, control device 70 returns to step S1 and repeats steps S1 to S8.

  The above is the method for controlling the amount of neutralizing agent input according to this embodiment. By performing the control as described above, the neutralizing agent input amount (hereinafter referred to as “necessary desulfurization input amount”) necessary for maintaining the desulfurization ability of the cleaning liquid injected from the injection nozzle 41, and the stored water Of the neutralizing agent input amount (hereinafter referred to as “necessary discharge input amount”) required for the cleaning liquid stored in the section 42 to clear the discharge regulation, the larger amount of the neutralizing agent is added to the circulation pipe 43. It is thrown into the flow path.

  However, the required desulfurization input is usually larger than the required discharge. This is because, when the pH value of the cleaning liquid sprayed from the spray nozzle 41 is set to a value that can maintain the desulfurization performance, the pH value of the cleaning liquid sprayed from the spray nozzle 41 is lowered by the EGR gas. It is because it is larger than the pH value (target stored water pH value = 6.8). In this case, only the cleaning liquid sprayed from the injection nozzle 41 needs to have a pH value for maintaining the desulfurization performance, and the cleaning liquid stored in the water reservoir 42 has a pH value for maintaining the desulfurization performance. There is no need to match. In the scrubber 40 according to the present embodiment, by introducing a neutralizing agent into the circulation pipe 43, only the cleaning liquid injected from the injection nozzle 41 can have a pH value for maintaining the desulfurization performance. Therefore, the scrubber 40 according to the present embodiment can suppress the amount of the neutralizing agent input compared to the scrubber in which the neutralizing agent is input to the water reservoir 42.

  However, in the present embodiment, when the required discharge amount becomes larger than the desulfurization required input amount due to the conditions such as the EGR gas flow rate, the neutralizer of the required discharge amount is flown through the circulation pipe 43. Will be thrown into. Thereby, the cleaning liquid stored in the water storage section 42 does not fall below the specified discharge value (out of the specified range).

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, the input amount of the neutralizing agent is controlled by a method as shown in FIG. 4, whereas in the present embodiment, both embodiments are different in that they are controlled by a method as shown in FIG. However, the other embodiments are basically the same in the other configurations. Hereinafter, the control method of the neutralizing agent input amount of the present embodiment will be described.

  Since steps S11 to S14 in the control method shown in FIG. 7 are the same as steps S1 to S4 of the first embodiment, the description thereof is omitted here. In step S15, the control device 70 calculates the injection side required input amount based on the deviation between the injection pH value and the target injection pH value. Specifically, the injection side required input amount is calculated such that the difference (deviation) between the injection pH value and the target injection pH value is eliminated. Here, the “necessary injection amount on the injection side” is the amount of neutralizing agent that is predicted to be necessary for the injection pH value to become the target injection pH value. Thus, step S15 corresponds to feedback control for the injection pH value. PID control can be adopted as this feedback control.

  Subsequently, the control device 70 calculates the required input amount on the stored water side based on the stored water pH value and the target stored water pH value (step S16). Specifically, the required input amount on the water storage side is calculated so that the difference (deviation) between the water storage pH value and the target water storage regulation pH value is eliminated. The “reserved water-side required input amount” here is an input amount of the neutralizing agent that is predicted to be necessary for the stored water pH value to become the target stored water pH value. As described above, the target stored water pH value is 6.8. Step S16 corresponds to feedback control for the stored water pH value. PID control can be adopted as this feedback control.

  Subsequently, the control device 70 determines the neutralizing agent input amount based on the basic neutralizing agent input amount, the injection side required input amount, and the stored water side required input amount (step S17). Specifically, among the basic neutralizer input amount, the injection side required input amount, and the stored water side required input amount, the largest value is set as the neutralizer input amount. Since the neutralizing agent input amount is thus determined, the neutralizing agent input amount does not fall below the basic neutralizing agent input amount. As described above, in the control of the neutralizing agent input amount of the present embodiment, the injection amount required on the injection side or the water storage side required determined by the feedback control while setting the basic neutralizing agent input amount determined by the feedforward control as the lower limit value. If the input amount exceeds the lower limit, this is determined as the neutralizer input amount.

  Subsequently, the control device 70 transmits a control signal to the neutralizing agent charging device 44 so that the charging amount of the neutralizing agent from the neutralizing agent charging device 44 becomes the neutralizing agent charging amount calculated in step S17. (Step S18). As a result, an appropriate amount of neutralizing agent is added to the cleaning liquid. When step S18 ends, control device 70 returns to step S11 and repeats steps S11 to S18.

  As described above, the method for controlling the amount of the neutralizing agent input is not limited to the method described in the first embodiment, and may be the method described in the present embodiment. Although this embodiment is partially different from the first embodiment in the method of controlling the amount of neutralizing agent input, while maintaining the sufficient desulfurization performance while suppressing the amount of neutralizing agent input to the cleaning liquid, the discharge restriction of the cleaning liquid Can still be cleared.

  The above is description of 1st Embodiment and 2nd Embodiment. Although the case where the scrubber 40 is an integrated type having all of the cleaning function, the cooling function, and the water storage function has been described above, a structure in which each function is realized by an independent device may be used. For example, the scrubber may be configured to have only a cleaning function, and a cooling device having a cooling function and a stored water tank having a stored water function may be provided separately from the scrubber.

  In the above description, the case where the neutralizing agent input amount is controlled by combining feedback control and feedforward control has been described. However, the neutralizing agent input amount may be controlled only by feedback control.

  In the above description, the engine system is for marine use and the cleaning liquid is discharged to the sea where there is a discharge restriction. However, even if it is an engine system or gas purification system installed on land, there is no restriction on the discharge of the cleaning liquid. In some cases, the present invention can be applied. The “gas purification system” referred to here is a system that cleans the exhaust gas discharged from the engine before being released to the atmosphere. That is, the scrubber described in the embodiment may be installed, for example, in an exhaust gas passage downstream of the engine system.

  According to the scrubber of the present invention, it is possible to maintain sufficient desulfurization performance while suppressing the amount of the neutralizing agent introduced into the cleaning liquid and to clear the cleaning liquid discharge regulation. Therefore, it is useful in the technical field of scrubbers.

DESCRIPTION OF SYMBOLS 10 Engine 40 Scrubber 41 Injection nozzle 42 Reservoir part 43 Circulation piping 44 Neutralizing agent injection apparatus 70 Control apparatus 100 Engine system

Claims (6)

A scrubber for cleaning exhaust gas discharged from an engine,
An injection nozzle for injecting a cleaning liquid into the exhaust gas;
Recovering and collecting the cleaning liquid sprayed from the spray nozzle, and a water storage part for discharging a part of the stored cleaning liquid to the outside,
A circulation pipe that supplies the cleaning liquid stored in the water reservoir to the spray nozzle;
A neutralizer feeding device for feeding the neutralizer into the flow path of the circulation pipe;
A controller for determining the amount of neutralizing agent to be charged from the neutralizing agent charging device,
The control device is configured to input a neutralizing agent obtained based on a deviation between a pH value of the cleaning liquid sprayed from the spray nozzle and a predetermined target injection pH value, and a pH value of the cleaning liquid stored in the water reservoir. The larger input amount of the neutralizer input amount obtained based on the deviation between the value and the predetermined target stored water pH value is determined as the input amount of the neutralizer supplied from the neutralizer input device. Constructed in a scrubber.   The scrubber according to claim 1, wherein the exhaust gas is EGR gas returned to the engine.   The said control apparatus is comprised so that the said target injection pH value may be set based on the sulfur content of the fuel used for the said engine, and the flow volume of the exhaust gas which passes the said scrubber. The scrubber described in 1.   The scrubber according to any one of claims 1 to 3, wherein the control device is configured to set a predetermined fixed value as the target stored water pH value. The controller is
Based on the sulfur content of the fuel used in the engine and the flow rate of the exhaust gas passing through the scrubber, the amount of the neutralizing agent that is predicted to be necessary for maintaining the desulfurization performance is input. Calculate the quantity,
The basic neutralizing agent input amount is set to a lower limit value, and the neutralizing agent input amount obtained based on the deviation between the pH value of the cleaning liquid sprayed from the spray nozzle and a predetermined target spray pH value , and the water reservoir Of the neutralizing agent obtained based on the deviation between the pH value of the cleaning liquid stored in the water and the predetermined target stored water pH value, and the neutralizing agent to be charged from the neutralizer charging device The scrubber according to any one of claims 1 to 4, wherein the scrubber is configured to be determined as an input amount.   An engine system comprising the scrubber according to any one of claims 1 to 5.

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