CN112135959A

CN112135959A - Control device for solid content separator, solid content separation device, exhaust gas scrubbing system for ship, and diesel engine for ship

Info

Publication number: CN112135959A
Application number: CN201980031392.9A
Authority: CN
Inventors: 佐野裕二; 桶谷尚史; 伊藤和久; 平冈直大
Original assignee: Japan Engine Corp
Current assignee: Japan Engine Corp
Priority date: 2018-06-26
Filing date: 2019-06-04
Publication date: 2020-12-25
Anticipated expiration: 2039-06-04
Also published as: JP2020002830A; KR102404292B1; JP7058565B2; CN112135959B; WO2020003927A1; KR20200138395A

Abstract

In order to easily discharge the solid content from the solid content separator at an appropriate timing, a centrifugal separator control device (133) (solid content separation device) includes a discharge timing control unit that determines a discharge timing for discharging the solid content from the centrifugal separator (122) based on a value corresponding to an output of the diesel engine (101). After absorbing solid components discharged from an engine (diesel engine (101)) into washing water, the solid components are separated from the washing water by a centrifugal separator (122) (solid component separator), and a centrifugal separator control device (133) controls the discharge timing of the separated solid components from the centrifugal separator (122).

Description

Control device for solid content separator, solid content separation device, exhaust gas scrubbing system for ship, and diesel engine for ship

Technical Field

The present invention relates to a marine exhaust gas scrubbing system, a solid content separator such as a centrifugal separator for purifying circulating water of the scrubbing system, a control device for a solid content separator constituting the solid content separator, and a marine diesel engine. The exhaust gas scrubbing system for a ship is provided with a scrubber for removing SOx, NOx, unburned carbon, and the like contained in the exhaust gas of a diesel engine for a ship.

Background

In marine diesel engines and the like, an exhaust gas scrubbing system can be used to remove particulate matter (solid components) such as unburned carbon contained in exhaust gas. In this exhaust gas scrubbing system, after the solid component is absorbed in the scrubbing water, which is the dust removal water, the solid component is separated from the scrubbing water by a solid component separator. In the solid content separator, the separated solid content is intermittently discharged when a predetermined amount of the solid content is accumulated. If the solid content is discharged without being sufficiently accumulated, the amount of washing water discharged together with the solid content increases, resulting in a decrease in concentration. On the other hand, if the solid content is accumulated excessively, it is solidified and difficult to discharge.

Thus, there is known a technique that: the discharge timing is controlled by a table prepared from the initial turbidity of the washing water discharged from the solid content separator and the amount of change corresponding to the initial turbidity (see, for example, patent document 1).

Patent document 1: japanese laid-open patent publication No. 2017-029919

Disclosure of Invention

Technical problem to be solved by the invention

However, when the turbidity is used for the control as described above, for example, when the measurement upper limit value of the turbidity measuring instrument is small, it may become impossible to follow the change in the amount of generation of the solid content according to the change in the engine load. Since the concentration of the solid component discharged from the solid component separator is controlled by the turbidity, the detection is performed in a state where the solid component overflows from the separation chamber of the solid component separator, and the indirect detection is performed. In this case, it is not always easy to discharge the solid component from the solid component separator at an appropriate timing.

The present invention has been made to solve the above problems, and an object of the present invention is to: it is easy to discharge the solid component from the solid component separator at an appropriate timing.

Technical scheme for solving technical problem

In order to achieve the above object, the present invention relates to a control device for a solid content separator, which separates a solid content discharged from an engine from wash water by the solid content separator after the solid content is absorbed in the wash water, and which controls a discharge timing of the separated solid content from the solid content separator, the control device comprising: the control device for the solid component separator includes a discharge timing control unit that determines a discharge timing at which the solid component is discharged from the solid component separator, based on a value corresponding to an engine output.

In this way, the solid components accumulated in the solid component separator are discharged at a timing corresponding to the operating state of the engine. Therefore, it is possible to easily prevent excessive accumulation of the solid content while keeping the concentration of the solid content high.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to easily discharge the solid component from the solid component separator at an appropriate timing.

Drawings

Fig. 1 is an explanatory diagram showing a schematic structure of an exhaust gas scrubbing system;

fig. 2 is a graph showing the relationship between the engine load, the EGR gas amount ratio, and the discharge time interval;

fig. 3 is a graph showing an example of control of the discharge timing.

Detailed Description

Hereinafter, an example of an exhaust gas scrubbing system as an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Wherein, the exhaust gas scrubbing system removes dust to the exhaust gas of diesel engine.

(brief Structure of exhaust gas washing System)

As shown in fig. 1, the off-gas scrubbing system includes a scrubbing device 110 and a centrifugal separation device (solid component separation device). The washing device 110 captures particulate matter (solid matter) such as unburned carbon contained in the exhaust gas of the diesel engine 101, and the centrifugal separation device (solid matter separation device) includes a centrifugal separator 122 (solid matter separator) for removing the solid matter in the washing water W (fluid to be treated) captured in the washing device 110.

More specifically, the scrubber 110 includes a scrubber 111, and a part of the exhaust gas discharged from the diesel engine 101 to the outside through the external exhaust pipe 103 is transported through the engine exhaust pipe 102, and the solid content in the transported exhaust gas is absorbed in the scrubbing water W in the scrubber 111 to remove dust. The cleaned exhaust gas in the scrubber 111 can be returned to the diesel engine 101 via the exhaust gas return pipe 104. The washing water W accumulated in the scrubber 111 is circulated by a pump, not shown, through a circulation pipe 112, and a part of the washing water W is sent to the centrifugal separator 122 to be purified as described below. Another part of the circulating washing water W is sprayed into the scrubber 111 together with the purified washing water W through the spray nozzle 113, thereby preventing the concentration of the solid components in the washing water W from rising.

A part of the washing water W circulated through the circulation pipe 112 is transferred into the centrifugal separator 122 through the inflow pipe 121, and after the solid components are removed by the centrifugal separator 122, returns to the circulation pipe 112 through the outflow pipe 123. Under the control of the centrifuge controller 133 (discharge timing controller), as described below, a valve (not shown) or the like is opened at a predetermined timing to discharge the solid components separated and removed from the washing water W.

The centrifuge control device 133 controls the timing of discharging the solid content in the centrifuge 122 in accordance with the engine load factor (engine output) of the diesel engine 101. The engine load factor is supplied from the EGR control device 131 to the centrifuge control device 133 via the scrubber control device 132, for example.

That is, the amount of exhaust gas flowing into the scrubber 111, i.e., the EGR gas amount, among the exhaust gas discharged from the diesel engine 101 is expressed by the exhaust gas amount × the EGR rate. The ratio of the EGR gas amount at each engine load factor to the EGR gas amount at the engine load factor of 100% (that is, the EGR gas amount ratio at the engine load factor of 100% is 100%), and the EGR gas amount ratio at each engine load factor is changed as in the actual measurement example in fig. 2, for example. Specifically, for example, if the EGR gas amount ratio is increased as the engine load factor is increased, the solid content in the exhaust gas flowing into the scrubber 111 is also increased. On the other hand, the higher the concentration of the solid content in the washing water W, the higher the separation efficiency of the centrifugal separator 122 with respect to the solid content. Therefore, as shown in fig. 2, generally, the time until the sludge space (slurry space) capable of containing the solid content of the centrifugal separator 122 is filled becomes shorter as the engine load factor becomes larger. (Note that the relationship between the engine load factor and the EGR gas amount is determined, for example, by actual equipment and is not limited to a proportional relationship or a monotonically increasing relationship.)

Therefore, as shown in the following (table 1), by controlling the solid content to be discharged at time intervals determined in accordance with the average load factor MR of the diesel engine 101, it is possible to easily prevent the solid content from being excessively accumulated and solidified, or discharged without being sufficiently accumulated and lowering the concentration. Here, since the engine load factor is often received by the EGR control device first, it is relatively easy to provide the engine load factor from the EGR control device 131 to the centrifugal separator control device 133 via the scrubber control device 132 as described above, but the engine load factor is not limited to this and may be provided to the centrifugal separator control device 133. Further, the engine load factor is not limited to the use, and substantially the same control can be performed as long as a value corresponding to the engine output is obtained. For example, the timing of discharging the solid content may be controlled based on various control values, measurement values, and an EGR gas amount ratio obtained by measuring or calculating the EGR gas amount.

[ Table 1]

(concrete example of control)

Next, a case where the diesel engine 101 is operated while the load factor is changed as shown in fig. 3 will be described as a specific control example.

First, when the diesel engine 101 is started, the operation of discharging the solid content accumulated in the sludge space of the centrifugal separator 122 is performed. This operation is not necessarily required, but by executing the sludge discharge operation at the initial stage of startup, even when the state of sludge residue in the sludge space is not clear at the initial stage of startup, the operation can be started reliably in the state where there is no sludge residue in the sludge space, so that stable operation can be performed easily.

The next solid content discharge operation was performed 23 minutes later (time a) corresponding to the case where the engine was operated at the engine load factor of 100%. That is, even if the concentration of the washing water W in the washer 111 is not known at this time, it is possible to perform a single discharge operation for a time when the engine load factor is 100% on the assumption that the washing water W reaches the maximum concentration between this time and the immediately preceding time, and thus it is possible to reliably prevent the solid content from being excessively accumulated.

On the other hand, if the engine load rate gradually increases to 50% after 23 minutes (time a) after the start of the diesel engine 101, the average load rate during this period, for example, the average of the load rates per 1 minute becomes 25%. Therefore, the next discharge time was set to 47 minutes later (time b). If the average load factor to the next discharge timing (time b) is 50%, the next discharge timing is determined to be 32 minutes later (time c).

Similarly, from (time c) to (time j), the average value of the engine load factors from the first discharge time to the second discharge time, which is the next time, is calculated, and the time to the third discharge time, which is the next time, is determined in accordance with the average value.

The solid content is discharged when the diesel engine 101 is stopped (time k), and this discharge operation is independent of the previous engine load factor. Although this discharge is not necessarily required, the sludge space of the centrifuge 122 is emptied, so that preparation can be made for the next operation. In addition, only one of the discharge operation at the time of the operation stop and the discharge operation at the time of the start may be performed, or the load state from the time of the start to the time of the first discharge operation may be stored and the discharge timing after the start may be determined based on the load state. However, by performing both the discharge operation at the start and the discharge operation at the stop as described above, or by performing the discharge at the shortest time interval first, even when an unexpected event occurs at the time of stopping the engine, for example, high safety can be easily ensured.

As described above, the solid content accumulated in the centrifugal separator 122 is discharged at the timing corresponding to the operating state of the diesel engine 101, and thus the solid content can be easily discharged at a necessary and sufficient timing. Therefore, it is possible to easily prevent the problem that the solid content is excessively accumulated, solidified, and clogged to make it difficult to discharge, and the problem that vibration or damage occurs in the centrifugal separator, while keeping the concentration of the solid content high.

Further, since a measuring instrument such as a turbidimeter is not required, the manufacturing cost can be easily reduced.

Description of the symbols:

101 diesel engine

102 exhaust pipe of engine

103 external exhaust pipe

104 waste gas return pipe

110 washing device

111 washing device

112 circulation pipe

113 spray nozzle

121 inflow pipe

122 centrifugal separator

123 outflow pipe

131 EGR control device

132 washer control device

133 centrifugal separator control means.

Claims

1. A control device for a solid content separator, which separates a solid content discharged from an engine from washing water by the solid content separator after the solid content is absorbed in the washing water, and which controls a discharge timing at which the separated solid content is discharged from the solid content separator, characterized in that:

the control device for the solid component separator includes a discharge timing control unit that determines a discharge timing at which the solid component is discharged from the solid component separator, based on a value corresponding to an engine output.

2. The control device of the solid component separator according to claim 1, wherein:

the discharge timing control unit determines a discharge timing at which the solid component is discharged from the solid component separator, based on the EGR gas amount ratio.

3. The control device of the solid component separator according to any one of claims 1 and 2, characterized in that:

the time from the second discharge timing to the third discharge timing is determined based on an average value of values corresponding to the engine output for each predetermined time interval in the time from the first discharge timing to the second discharge timing that follows.

4. The control device of the solid component separator according to any one of claims 1 to 3, characterized in that:

the solid content is discharged at least one of when the engine starts to operate and when the engine stops operating.

5. The control device of the solid component separator according to any one of claims 1 to 4, wherein:

the time from the start of the engine to the first discharge time corresponds to the time when the engine output is the highest.

6. A solid component separating apparatus characterized in that:

the solid component separation apparatus includes: the control device for a solid component separator according to any one of claims 1 to 5, and the solid component separator.

7. An exhaust gas scrubbing system, characterized by:

the exhaust gas scrubbing system includes: the solid component separating device according to claim 6, and a scrubber for storing the washing water.

8. A marine diesel engine, characterized in that:

the marine diesel engine comprising the exhaust gas scrubbing system of claim 7.