WO2022201947A1

WO2022201947A1 - Exhaust gas treatment apparatus and exhaust gas treatment method

Info

Publication number: WO2022201947A1
Application number: PCT/JP2022/005339
Authority: WO
Inventors: 和芳糸川; 広幸當山
Original assignee: 富士電機株式会社
Priority date: 2021-03-23
Filing date: 2022-02-10
Publication date: 2022-09-29
Also published as: JP7380946B2; CN116096475A; JPWO2022201947A1; KR20230044491A

Abstract

Provided is an exhaust gas treatment apparatus that can switch an operation mode between a closed-loop operation in which used liquid that has been used in the treatment of exhaust gas is circulated and an open-loop operation in which the used liquid is externally discharged. The exhaust gas treatment apparatus comprises: a reaction tower to which exhaust gas is supplied and which purifies the exhaust gas by using a liquid; a retention unit which retains used liquid that was used to purify the exhaust gas, and which supplies, into the reaction tower, used liquid for which the purification capability was restored by using an alkaline agent in the closed-loop operation; and an insertion unit which, if a closed-loop operation is to be initiated, inserts the alkaline agent into the retention unit before the supply of used liquid from the storage unit into reaction tower is started.

Description

Exhaust gas treatment device and exhaust gas treatment method

The present invention relates to an exhaust gas treatment device and an exhaust gas treatment method.

2. Description of the Related Art Exhaust gas treatment devices called scrubber devices that purify exhaust gas by neutralizing sulfur components in the exhaust gas with a scrubber liquid such as seawater are widely used. Operation of the scrubber device includes open loop operation and closed loop operation. In open-loop operation, the scrubber device discharges to the outside the spent scrubber liquid that has been used to clean the exhaust gas. In closed-loop operation, the scrubber apparatus restores the cleaning ability of the spent scrubber liquid by dosing the spent scrubber liquid with an alkaline agent, and circulates the spent scrubber liquid with the restored cleaning ability. Scrubber devices for marine vessels that perform closed-loop operation using magnesium hydroxide or magnesium oxide are known (eg, Patent Document 1). In a scrubber device for purifying boiler exhaust gas used on land, there is a known technique for controlling the amount of magnesium hydroxide input based on the sulfur content (SO _x ) concentration in the purified exhaust gas (for example, , Patent Documents 2 to 4). As a related technology, there is known a pH control technology using an alkaline agent in a scrubber device (for example, Patent Documents 5 and 6). As a related technique, a technique for estimating the amount of sulfur component absorbed by the scrubber liquid (for example, Patent Documents 7 and 8) is known.
Patent Document 1 International Publication WO2017/194645 Patent Document 2 Japanese Patent Laid-Open No. 9-66219 Patent Document 3 Japanese Patent Laid-Open Publication No. 7-275649 Patent Document 4 Japanese Patent Laid-Open Publication No. 8-196863 Patent Document 5 International Publication WO2012/000790 Patent Document 6 JP-A-3-267114 Patent document 7 International publication WO2014/119513 Patent document 8 International publication WO2016/009549

Problem to be solved

In closed-loop operation, when using an alkaline agent that has a lower solubility or reaction rate than sodium-containing alkaline agents such as sodium hydroxide, sodium carbonate, and sodium bicarbonate, in order to dissolve the alkaline agent in the scrubber liquid, takes longer. Therefore, compared to the case of using a sodium-containing alkaline agent, it is necessary to increase the size of the buffer tank (reservoir) for storing the scrubber liquid for dissolving the alkaline agent, or to provide a plurality of tanks. occur. However, in the exhaust gas treatment apparatus, it is desirable to reduce the capacity of the reservoir.

General disclosure

In order to solve the above problems, in one aspect of the present invention, an operation is performed between a closed loop operation for circulating the used liquid used for treating the exhaust gas and an open loop operation for discharging the used liquid to the outside. To provide an exhaust gas treatment device capable of switching modes. The exhaust gas treatment device may include a reaction tower. The reaction tower is supplied with exhaust gas and purifies the exhaust gas with liquid. The exhaust gas treatment device may include a reservoir. The storage section may store used liquid that has been used to purify the exhaust gas. The reservoir may supply the spent liquid, which has been purified by the alkaline agent during closed-loop operation, into the reactor. The exhaust gas treatment device may include an inlet. When initiating closed-loop operation, the dosing section may dose the alkaline agent into the reservoir before starting to supply the spent liquid from the reservoir into the reactor.

The input unit may input at least one of magnesium oxide and magnesium hydroxide into the storage unit as an alkaline agent.

The input unit may input solid powder of at least one of magnesium oxide and magnesium hydroxide into the storage unit as an alkaline agent.

The input unit may input magnesium oxide into the storage unit as an alkaline agent.

When the mode of operation is switched to closed-loop operation, at a first point in closed-loop operation, the dosing section is supplied with an amount of magnesium oxide that is greater than the amount of magnesium oxide that can be neutralized with the amount of sulfur that the liquid absorbs in a single circulation. may be introduced into the reservoir.

When the operation mode is switched to closed-loop operation, at the first timing, the input unit oxidizes an amount that is 2 times or more and 400 times or less of the amount of sulfur components absorbed by the liquid in one circulation and the amount that can be neutralized. Magnesium may be introduced into the reservoir.

When the operation mode is switched to the closed-loop operation, at the first timing, the input unit introduces magnesium oxide into the storage unit in an amount larger than the amount that can be neutralized with the amount of sulfur component absorbed by the liquid in one circulation. you can put it in.

The injection unit may replenish the storage unit with a smaller amount of magnesium oxide than the amount injected at the first timing at a second timing after the first timing while the closed-loop operation continues.

The exhaust gas treatment device may further include an adjustment unit. The adjusting unit adjusts the charging amount of magnesium oxide charged into the reservoir before starting the supply of the spent liquid from the reservoir into the reaction column when the operation mode is switched from the open-loop operation to the closed-loop operation. you can

The adjustment unit may estimate the sulfur component amount absorbed by the liquid in one circulation based on the output of the combustion device that produces the exhaust gas and the sulfur concentration contained in the fuel oil used in the combustion device. . The adjustment unit may adjust the input amount based on the estimated sulfur content.

The adjustment unit adjusts the dosage based on the sulfur content of the gas released from the reactor during open-loop operation and the planned power output of the combustion device that produces the exhaust gas after the operating mode is switched to closed-loop operation. You can

The adjustment unit adjusts the hydrogen ion exponent (pH) of each of the liquid supplied to the reactor during open-loop operation and the used liquid discharged from the reactor to the outside, and the exhaust gas after the operation mode is switched to closed-loop operation. The input amount may be adjusted based on the planned output value of the combustion device that produces the

When the operation mode is switched from open-loop operation to closed-loop operation, the adjustment unit may adjust the input amount based on the amount of magnesium oxide remaining in the reservoir during the previous closed-mode operation.

The exhaust gas treatment device may further include a reservoir cleaning mechanism. The reservoir cleaning mechanism may clean the inside of the reservoir.

The exhaust gas treatment device may further include a pipe cleaning mechanism. The pipe cleaning mechanism may clean the inside of the pipe between the reaction tower and the reservoir.

In a second aspect of the present invention, an exhaust gas treatment capable of switching the operation mode between a closed loop operation for circulating the used liquid used for exhaust gas treatment and an open loop operation for discharging the used liquid to the outside. provide a way. The exhaust gas treatment method may comprise storing the spent liquid used to clean the exhaust gas. The exhaust gas treatment method may comprise the step of contacting the exhaust gas with the spent liquid, which has been reconstituted with an alkaline agent during closed-loop operation. The exhaust gas treatment method may comprise dosing the stored spent liquid with an alkaline agent prior to feeding the spent liquid into contact with the exhaust gas when closed loop operation is initiated.

It should be noted that the above outline of the invention does not list all the necessary features of the present invention. Subcombinations of these feature groups can also be inventions.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining schematic structure of the waste gas treatment apparatus 1 of one Embodiment of this invention. FIG. 4 shows experimental values of pH increase rate based on MgO concentration. FIG. 4 is a diagram showing an example of experimental values of reaction rate constants; It is a figure explaining schematic structure of the waste gas treatment apparatus 2 of a comparative example. 3 is a flow chart showing an example of an exhaust gas treatment method in the exhaust gas treatment apparatus 1. FIG. 4 is a flow chart showing another example of an exhaust gas treatment method in the exhaust gas treatment apparatus 1. FIG. It is a flow chart which shows an example of an input amount adjustment process. It is a flowchart which shows the other example of an input amount adjustment process. It is a flowchart which shows the other example of an input amount adjustment process. It is a flowchart which shows the other example of an input amount adjustment process. 5 is a flowchart showing an example of cleaning processing;

Although the present invention will be described below through embodiments of the invention, the following embodiments do not limit the invention according to the scope of claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

FIG. 1 is a diagram illustrating a schematic configuration of an exhaust gas treatment apparatus 1 according to one embodiment of the present invention. The exhaust gas treatment device 1 reduces sulfur components in the exhaust gas 100 generated in the combustion device 3 to purify the exhaust gas 100 . The combustion device 3 may be an engine or a boiler, preferably an engine, especially a marine engine. The sulfur component may include sulfur compounds such as SOx (sulfur oxides).

The exhaust gas treatment device 1 includes a reaction tower 10. In the reaction tower 10, the exhaust gas 100 from the combustion device 3 is brought into contact with the scrubber liquid, which is seawater. The scrubber liquid may be a liquid such as seawater or an alkaline aqueous solution. Exhaust gas 100 from the combustion device 3 is introduced into the reaction tower 10 through the combustion gas exhaust pipe 12 . The scrubber liquid is sprayed from a spray nozzle 13 inside the reactor 10 . The scrubber liquid is introduced into the spray nozzle 13 via the scrubber liquid tube 14 .

When the exhaust gas 100 and the scrubber liquid come into gas-liquid contact, sulfur components in the exhaust gas 100 are absorbed into the scrubber liquid. The sulfur component dissolves in the scrubber to form sulfite H ₂ SO ₃ . In fact, sulfite H ₂ SO ₃ dissociates into hydrogen ions H ⁺ and hydrogen sulfite ions HSO ₃ ⁻ and exhibits acidity. The sulfur content in the exhaust gas 100 is reduced by absorbing the sulfur content in the scrubber liquid. The purified gas with reduced sulfur content is discharged from the gas discharge portion 15 to the outside.

When the scrubber liquid is seawater, hydrogen carbonate ions (HCO ₃ ⁻ ), carbonate ions (CO ₃ ²⁻ ), and sulfite H ₂ SO ₃ , which are alkaline components in seawater, are neutralized. The scrubber liquid whose alkali component is insufficient due to the neutralization reaction becomes used scrubber liquid (used liquid) and is collected in the lower part of the reaction tower 10 . Spent scrubber liquid passes through the spent scrubber line 16 .

The exhaust gas treatment device 1 is configured so that the operation mode can be switched between open loop operation and closed loop operation. When the mode of operation is open loop operation, the valve 18 between the spent scrubber line 16 and the discharge line 17 is opened and the valve 20 between the spent scrubber line 16 and the circulation line 19 is closed. In open loop operation, spent scrubber liquid is directed from the spent scrubber pipe 16 to the discharge pipe 17 and the spent scrubber liquid is discharged from the seawater outlet 21 . Also, in open loop operation, seawater is taken in from the seawater intake 22 as scrubber liquid. In open loop operation, seawater is introduced into the scrubber liquid line 14 via the seawater line 24 , the valve 32 and the scrubber liquid pump 23 . In open loop operation, the valve 32 between the seawater pipe 24 and the scrubber liquid pipe 14 is opened. On the other hand, a valve 33, which will be described later, is closed. Thus, in open loop operation, spent scrubber liquid is discharged to the outside.

The exhaust gas treatment device 1 includes a storage section 30 and an input section 40 . When the mode of operation is closed loop operation, valve 20 between spent scrubber line 16 and circulation line 19 is opened and valve 18 between spent scrubber line 16 and discharge line 17 is closed.

The used scrubber liquid is stored in the storage section 30 from the used scrubber pipe 16 via the circulation pipe 19 . Then, the charging unit 40 charges the alkaline agent into the storage unit 30 . By the charging unit 40 charging the used scrubber liquid in the storage unit 30 with the alkaline agent, the ability of the used scrubber liquid in the storage unit 30 to purify the exhaust gas 100 is recovered. The ability to purify the exhaust gas 100 may refer to the ability to neutralize sulfurous acid or the like in the exhaust gas 100 . The storage unit 30 supplies the used scrubber liquid whose purification ability has been restored by the alkaline agent into the reaction tower 10 during the closed loop operation. Specifically, in the reservoir 30, the used scrubber liquid whose purification ability has been restored is supplied to the reaction tower 10 via the circulating scrubber liquid supply pipe 34, the valve 33, the pump 23, and the scrubber liquid pipe 14. .

During closed loop operation, basically valve 33 between circulating scrubber liquid supply pipe 34 and scrubber liquid pipe 14 is opened and valve 32 between seawater pipe 24 and scrubber liquid pipe 14 is closed. However, if the liquid level of the used scrubber is reduced during the course of closed loop operation, the valve 32 may be temporarily opened to obtain seawater to replenish the liquid level to the proper level.

The reservoir 30 is a tank that stores the used scrubber liquid and supplies the used liquid whose purification ability has been restored to the reaction tower 10 . The reservoir 30 may be a buffer tank. Reaction tower 10, used scrubber pipe 16, circulation pipe 19, reservoir 30, circulating scrubber liquid supply pipe 34, and scrubber liquid pipe 14 form a circulation route, and the scrubber liquid is cyclically flowing in the route. A section 30 is provided.

When starting the closed-loop operation, the charging section 40 charges the alkaline agent into the storage section 30 before starting to supply the used scrubber liquid from the storage section 30 into the reaction tower 10 . For example, while the valve 33 remains closed, the input unit 40 injects the alkaline agent into the storage unit 30 .

Input unit 40 may input at least one of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH) ₂ ) into storage unit 30 as an alkaline agent. Magnesium oxide and magnesium hydroxide require a smaller volume of chemicals to purify the exhaust gas 100 than sodium hydroxide, sodium carbonate, sodium bicarbonate, and other sodium-containing alkali agents, so the storage space for the alkali agents can be saved. can be

In particular, the input unit 40 may input solid powder of at least one of magnesium oxide and magnesium hydroxide into the storage unit 30 as an alkaline agent. Therefore, it is not necessary to previously dissolve magnesium oxide or magnesium hydroxide in the scrubber liquid to form a slurry. This eliminates the need for a space for previously dissolving the magnesium oxide or magnesium hydroxide in the scrubber liquid to form a slurry. The input unit 40 inputs magnesium oxide into the storage unit 30 as an alkaline agent. Magnesium oxide requires less chemical cost than magnesium hydroxide.

When magnesium oxide is dissolved in a water-based scrubber liquid, a hydration reaction of MgO (magnesium oxide)+H ₂ O (water)→Mg(OH) ₂ (magnesium hydroxide) occurs. Then, a neutralization reaction of Mg(OH) ₂ (magnesium hydroxide)+H ₂ SO ₃ (sulfurous acid)→MgSO ₃ (magnesium sulfite)+2H ₂ O (water) occurs. MgSO ₃ (magnesium sulfite) is oxidized to MgSO ₄ (magnesium sulfate).

When magnesium oxide (MgO) is used as the alkaline agent, the solubility of Mg(OH) ₂ (magnesium hydroxide) is affected by the hydration reaction to Mg(OH) ₂ (magnesium hydroxide). be. The solubility of Mg(OH) ₂ (magnesium hydroxide) is calculated as follows.

The pH of a saturated aqueous solution of Mg(OH) ₂ (magnesium hydroxide) is 10.5. The pOH of a saturated aqueous solution of Mg(OH) ₂ (magnesium hydroxide) is represented by Formula 1 below.

From Equation 1 above, the concentration of OH ⁻ ions (hydroxide ions) in a saturated aqueous solution of Mg(OH) ₂ (magnesium hydroxide) is represented by Equation 2 below.

The valence of OH ⁻ ion (hydroxide ion) in Mg(OH) ₂ (magnesium hydroxide) is 2. Therefore, if the solubility of MgO (magnesium oxide) is Cs, Cs is represented by the following formula 3.

From Equation 3 above, the solubility of MgO (magnesium oxide) is 0.158×10 ⁻³ mol/L (liter). This solubility is small compared to sodium-containing alkaline agents. Therefore, it takes time to increase the pH of the scrubber liquid (circulating water) using magnesium oxide (MgO) as an oxidizing agent. By increasing the concentration (input amount) of magnesium oxide (MgO), the solid surface area S can be increased. As shown in the following reaction rate formula, the hydration reaction can be promoted by increasing the fixed surface area (S) of the alkaline agent powder. C: Mg(OH) ₂ concentration, k: reaction rate constant, S: solid surface area.

Since the scrubber liquor contains H ₂ SO ₄ , Mg(OH) ₂ (magnesium hydroxide) dissolved in the scrubber liquor is neutralized with the scrubber liquor. Therefore, C=0 can be set in Equation 4. Also, kS can be calculated as 2.7×10 ⁻⁴ from the dissolution rate of MgO (magnesium oxide) in 1 L of pure water calculated from experimental results (described later). From the above, Formula 4 is expressed as Formula 5 below.

The following formula 6 is obtained from the above formulas 3 and 5.

If the goal is to dissolve M [m·mol/L] of MgO (magnesium oxide) in the scrubber liquid at time t, the target value of the dissolution rate dC/dt is expressed by Equation 7 below.

From

Equations

6 and 7 above, the fixed surface area (S) of the alkaline agent powder that reaches the target dC/dt is represented by Equation 8 below.

The dissolution rate dC/dt can reach the target dC/dt by making the fixed surface area (S) of the powder of the alkaline agent equal to or greater than the value calculated by Equation 8. As a result, the hydration reaction is promoted. As a result, the pH of the used scrubber liquid is increased due to MgO, and the time required for obtaining the used scrubber liquid whose purification ability (neutralization ability) has been restored can be shortened.

FIG. 2 is a diagram showing experimental values of the pH increase rate based on the concentration of MgO. The horizontal axis indicates elapsed time. The vertical axis indicates the hydrogen ion exponent (pH). In this experimental example, water was used as the scrubber liquid. The scrubber liquid had a pH of about 6, but as a result of absorbing 2 mmol/L of sulfur component (SOx), the pH decreased to about 3. When MgO with a concentration of A is added to the scrubber liquid whose pH is lowered and the ability to purify the exhaust gas 100 is lowered, and when MgO with a concentration of 2A (twice the concentration of A) is added, , the time for the pH of the scrubber liquor to return to its original level. According to this experiment, it is shown that by doubling the MgO concentration, the time required for the pH of the scrubber liquid to return to its original level and the ability to purify the exhaust gas 100 to recover can be shortened to 1/2 or less. rice field.

When the operation mode is switched to the closed-loop operation, at the first timing t1 in the closed-loop operation, the input unit 40 has an amount larger than the amount of sulfur components that can be neutralized with the amount of sulfur components absorbed by the scrubber liquid in one circulation. of magnesium oxide may be introduced into the reservoir 30 . The amount larger than the amount capable of neutralization reaction may be an amount of 2 to 400 times the amount of the sulfur component and the amount capable of neutralization reaction. The first timing t1 may be the start of operation in closed loop operation.

Such excessive addition of magnesium oxide (MgO) can promote the hydration reaction from magnesium oxide (MgO) to Mg(OH) ₂ (magnesium hydroxide) by increasing the solid surface area. . Therefore, by excessive charging of magnesium oxide (MgO) to the reservoir 30, the pH of the scrubber liquid returns to the original level and the time until the exhaust gas 100 purifying ability is recovered can be shortened.

FIG. 3 is a diagram showing an example of experimental values of reaction rate constants. The horizontal axis in FIG. 3 is elapsed time (s), and the vertical axis is In(Cs/(Cs−C)). Based on the experimental results of the dissolution rate of ^MgO2mmol in 1L (liter ⁾ of pure water shown in FIG. ¹ ) was obtained. In addition, H ₂ SO ₃ (sulfurous acid) is present in the scrubber liquid, and dissolved Mg(OH) ₂ (magnesium hydroxide) is immediately consumed by a neutralization reaction. Therefore, since C can be set to 0 in the reaction rate formula (Equation 1), the dissolution rate dC/dt=kS×Cs.

In order to make the pH of the scrubber liquid equivalent to that of seawater, the target value of the pH of the scrubber liquid was set to 8.1. The retention time that can be retained in the reservoir 30 was set to 120 seconds, and the sulfur component concentration absorbed by the scrubber liquid in one circulation was set to 2 mmol/L. Based on these conditions, the dissolution rate dC/dt=kS*Cs is calculated. Using the value of kS of 2.7×10 ⁻⁴ (s ⁻¹ ), let Cs be the concentration of magnesium oxide that can be neutralized with the sulfur component concentration of 2 mmol/L absorbed by the scrubber liquid in one circulation, The dissolution rate dC/dt is 4.27×10 ⁻⁸ (mol/L/s). On the other hand, if the target is to dissolve 2 mmol/L of MgO in 120 seconds, the target value of the dissolution rate dC/dt is 0.002 mol/L/120 (s) = 1.67 × 10 ^-5 (mol /L/s).

Although affected by the target pH value, etc., the input unit 40 is designed to remove sulfur absorbed by the scrubber liquid in one circulation before starting to supply the used scrubber liquid from the storage unit 30 into the reaction tower 10. Magnesium oxide in an amount larger than the amount that can be neutralized with the amount of the components may be introduced into the reservoir 30 . The amount of sulfur components absorbed by the scrubber liquid in one circulation and the amount of magnesium oxide that is larger than the amount that can be neutralized is twice the amount of sulfur components that the scrubber liquid absorbs and the amount that can be neutralized in one circulation. The amount of magnesium oxide may be 400 times or less, the amount of magnesium oxide may be 100 times or more and 400 times or less, and more preferably the amount of magnesium oxide may be 300 times or more and 400 times or less. good.

FIG. 4 is a diagram illustrating a schematic configuration of an exhaust gas treatment apparatus 2 of a comparative example. The exhaust gas treatment apparatus 2 of the comparative example includes a reaction tower 10, a used scrubber pipe 16, a circulation pipe 19, a reservoir 30, a circulating scrubber liquid supply pipe 34, a scrubber liquid pipe 14, and a preparation section 62 and a storage outside the circulation path. In section 64 , magnesium oxide (MgO) is introduced by the introduction section 60 . The dispensing unit 62 is a tank for dissolving magnesium oxide (MgO), and the storage unit 64 is a tank for storing magnesium hydroxide Mg(OH) ₂ produced by a hydration reaction by dissolving magnesium oxide (MgO). be. Magnesium oxide (MgO) melted by dispensing unit 62 is introduced into storage unit 64 by pump 63 . Magnesium hydroxide Mg(OH) ₂ stored in storage unit 64 is introduced into circulation pipe 19 by pump 65 .

Thus, dissolving magnesium oxide (MgO) and storing magnesium hydroxide Mg(OH) ₂ (magnesium hydroxide) in a plurality of tanks outside the circulation path different from reservoir 30 is already sufficient. Hydration reaction can be allowed to proceed. Therefore, when starting closed-loop operation, it is not necessary to charge excess magnesium oxide before starting the supply of spent scrubber liquid from reservoir 30 into reactor 10 . However, according to the comparative example, in addition to the storage section 30 as a buffer tank, the preparation section 62 and the storage section 64 are required, which makes it difficult to achieve space saving.

As shown in FIG. 1, the exhaust gas treatment apparatus 1 may include an adjustment section 50, a control section 51, a storage section 53, and a setting section . The control unit 51 controls the entire exhaust gas treatment apparatus 1 including the

valves

18, 20, 32, 33, and the like. The controller 51 may be a computer.

The adjustment unit 50 adjusts the amount of magnesium oxide that is introduced into the reservoir 30 before starting to supply the used scrubber liquid from the reservoir 30 into the reaction tower 10 . However, the exhaust gas treatment apparatus 1 is not necessarily limited to adjusting the charging amount as long as the alkaline agent is excessively charged during the closed loop operation.

The setting unit 54 sets the sulfur content concentration of the fuel oil used in the combustion device 3 and the planned output value of the combustion device 3 that produces the exhaust gas 100 after the operation mode is switched to the closed loop operation. In one example, closed-loop operation may reduce the output of combustion device 3 from 80% to 40% of its rating due to a vessel sailing near a port. The planned output value may thus include information on the output value of the combustion device 3 scheduled due to the course of the ship. The setting unit 54 may set the sulfur content concentration of the fuel oil, the planned output value, etc. based on the information input by the user, and sets the sulfur content concentration of the fuel oil, the planned output value, etc. based on the measuring device. May be set. The storage unit 53 may store various types of information set by the setting unit 54, such as the sulfur concentration of the fuel oil and the planned output value of the combustion device 3, as a database.

The adjustment unit 50 acquires information set by the setting unit 54 and stored in the storage unit 53, information on the output of the combustion device 3 (engine load, etc.), and information on values detected by various sensors. The adjustment unit 50 adjusts the amount of magnesium oxide, which is an alkaline agent, supplied by the supply unit 40 according to the acquired information. The exhaust gas treatment device 1 may include a pH sensor 35, a pH sensor 36, and a sulfur component sensor 37 as various sensors. The pH sensor 35 measures the pH of the scrubber liquid (seawater) supplied to the reactor 10 during open loop operation. For example, the pH sensor 35 measures the pH of sea water while the ship is underway. The pH sensor 36 measures the pH of the used scrubber liquid discharged from the reaction tower 10 to the outside. Sulfur content sensor 37 measures the amount of sulfur content in the gas discharged from reactor 10 during open loop operation.

Based on the output of the combustion device 3 that produces the exhaust gas 100 and the concentration of sulfur contained in the fuel oil used in the combustion device 3, the adjustment unit 50 adjusts the amount of sulfur component that the liquid absorbs in one circulation. The dosage may be adjusted based on the estimated sulfur content. As a result, based on the estimated value of the amount of sulfur component absorbed by the liquid in one cycle, the larger the estimated value of the amount of sulfur component to be absorbed, the more the amount of alkaline agent supplied can be increased, and finer adjustments can be made. It becomes possible.

The adjustment unit 50 adjusts the amount of sulfur in the gas released from the reaction tower 10 during open-loop operation, and the planned output value of the combustion device 3 that produces the exhaust gas 100 after the operation mode is switched to the closed-loop operation. You can adjust the dosage. If the sulfur content of the gas discharged from the reactor 10 during open loop operation is high, the dosage of the alkali agent may be increased to enhance the absorption of the sulfur content. Also, the lower the planned output value, the smaller the amount of alkaline agent supplied.

The adjustment unit 50 adjusts the hydrogen ion exponent (pH) of each of the scrubber liquid (seawater) supplied to the reaction tower 10 and the spent scrubber liquid discharged from the reaction tower 10 during open loop operation, and the operation mode. The input amount may be adjusted based on the planned power output of the combustion device 3 that produces the exhaust gas 100 after being switched to closed-loop operation. The higher the pH value of the scrubber liquid (seawater) supplied to the reaction tower 10 during open-loop operation, the lower the dosage of the alkali agent may be. The lower the pH of the used scrubber liquid discharged from the reaction tower 10 to the outside, the greater the amount of alkali agent introduced. The adjusting unit 50 can also estimate the amount of sulfur in closed-loop operation from information in open-loop operation.

The adjustment unit 50 adjusts the input amount based on the amount of magnesium oxide remaining in the storage unit 30 during the previous closed mode operation when the operation mode is switched from the open loop operation to the closed loop operation. you can If a large amount of magnesium oxide from the previous closed mode operation remains, the amount of newly added magnesium oxide may be reduced.

The exhaust gas treatment device 1 may include a reservoir cleaning mechanism 38 and a pipe cleaning mechanism 39 . The exhaust gas treatment apparatus 1 is excessively charged with magnesium oxide to increase the solid surface area of the alkaline agent such as magnesium oxide, thereby promoting the hydration reaction. Therefore, magnesium hydroxide and magnesium oxide tend to aggregate in the reservoir 30 , the circulating scrubber liquid supply pipe 34 , the valve 33 , the pump 23 , and the scrubber liquid pipe 14 . Reservoir cleaning mechanism 38 may clean reservoir 30 each time closed-loop operation ends. Reservoir cleaning mechanism 38 may remove aggregated material from within reservoir 30 and out. The storage part cleaning mechanism 38 may inject a cleaning liquid into the storage part 30 to clean it.

Every time the closed-loop operation ends, the pipe cleaning mechanism 39 is configured to clean the circulating scrubber liquid supply pipe 34 between the inlet of the scrubber liquid to the reaction tower 10 and the supply port from the reservoir 30, the valve 33, the pump 23, The scrubber liquid tube 14 may be cleaned.

The exhaust gas treatment apparatus 1 configured as described above performs processing as follows.

FIG. 5 is a flowchart showing an example of an exhaust gas treatment method in the exhaust gas treatment apparatus 1. FIG. When the open loop operation instruction is given (step S10: YES), the control unit 51 executes the open loop operation (step S12). Specifically, control unit 51 opens valve 18 and valve 32 and closes valve 20 and valve 33 .

If there is no open loop operation instruction (step S10: NO) and no closed loop operation instruction (step S14: NO), the process of the control unit 51 returns to step S10. When there is no open-loop operation instruction (step S10: NO) and there is a closed-loop operation instruction (step S14: YES), the exhaust gas treatment device 1 executes the processes from steps S16 to S28.

The control unit 51 opens the valve 20 and closes the valve 18. However, the control unit 51 keeps the valve 33 closed and the valve 32 open for a predetermined period of time even if the closed loop operation instruction is given. As a result, the storage unit 30 stores the used scrubber liquid (step S16).

Wait until the storage of the used scrubber liquid reaches a predetermined storage amount in the storage unit 30 (step S18: YES). The adjusting unit 50 may adjust the initial charging amount of the alkaline agent, preferably magnesium oxide (step S20). The processes of step S18 and step S20 may be executed in parallel.

The injection unit 40 injects an alkaline agent, preferably magnesium oxide, into the stored used scrubber liquid at a first timing t1 (step S22). As described above, the first timing t1 may be one timing in the closed-loop operation, or may be the start of the closed-loop operation. In particular, the injection unit 40 injects an alkaline agent, preferably magnesium oxide, into the stored used scrubber liquid before supplying the used scrubber liquid to contact the exhaust gas 100 . Specifically, before the valve 33 remains closed and the used scrubber liquid is started to be supplied from the reservoir 30 to the circulating scrubber liquid supply pipe 34, the input unit 40 supplies an alkaline agent, preferably magnesium oxide, Put into the used scrubber liquid that is stored.

The control unit 51 waits for the scheduled time to pass (step S24: YES), closes the valve 32, and opens the valve 33. As a result, the reservoir 30 supplies the scrubber liquid whose cleaning ability has been restored by the introduction of the alkaline agent to the reaction tower 10 (step S26). The scrubber liquid is supplied from the reservoir 30 into the reaction tower 10 via the circulating scrubber liquid supply pipe 34 , the valve 33 , the pump 23 and the scrubber liquid pipe 14 . Thereby, the scrubber liquid comes into contact with the exhaust gas 100 to purify the exhaust gas 100 .

The used scrubber liquid returns to the storage section 30 through the storage section 30 , the circulating scrubber liquid supply pipe 34 , the scrubber liquid pipe 14 reaction tower 10 , the used scrubber pipe 16 and the circulation pipe 19 . At a second timing t2 after the first timing t1 during the continuation of the closed-loop operation, the charging unit 40 replenishes the reservoir with a smaller amount of magnesium oxide than the charging amount at the first timing t1. (step S28). The process of step S28 may be repeatedly performed while the closed-loop operation continues.

FIG. 6 is a flow chart showing another example of the exhaust gas treatment method in the exhaust gas treatment apparatus 1. FIG. When the open loop operation instruction is given (step S30: YES), the control unit 51 executes the open loop operation (step S32). However, when the predetermined amount of used scrubber liquid is not stored in the storage section 30 (step S34: NO), the control section 51 closes the valve 18 and opens the valve 20 . As a result, the storage unit 30 stores the used scrubber liquid (step S36). After waiting for a predetermined amount of used scrubber liquid to be stored in the reservoir 30 (step S34: YES), the controller 51 may open the valve 18 and close the valve 20 . The control unit 51 generates a closed-loop operation ready signal, which is a signal indicating that preparations for the closed-loop operation have been completed.

In a state where preparations for closed-loop operation are complete, the control unit 51 accepts a closed-loop operation instruction (step S40). If the closed-loop operation instruction has not been issued (step S40: NO), the process returns to step S30. When the control unit 51 receives the closed loop operation instruction (step S40: YES), the processing from step S42 to step S49 is executed. Since the processing from step S42 to step S49 is the same as the processing from step S20 to step S28 in FIG. 5, repeated description will be omitted.

FIG. 7 is a flowchart showing an example of the input amount adjustment process. FIG. 7 may be a subroutine of the process of step S20 of FIG. 5 or step S42 of FIG.

The adjustment unit 50 acquires the output value of the combustion device 3, for example, the ship's engine (step S50). Further, the adjustment unit 50 acquires information on the concentration of sulfur contained in the fuel oil used in the combustion device 3 from the storage unit 53 (step S52). Information on the concentration of sulfur contained in the fuel oil may be input in advance by the user using the setting unit 54 .

Based on the output value of the combustion device 3 and the concentration of sulfur contained in the fuel oil, the adjustment unit 50 estimates the amount of sulfur component absorbed by the scrubber liquid in one cycle (step S54). The amount of sulfur component absorbed by the scrubber liquid in one circulation means that the scrubber liquid passes through the reservoir 30, the circulating scrubber liquid supply pipe 34, the scrubber liquid pipe 14, the reaction tower 10, the used scrubber pipe 16, and the circulation pipe 19. It is the amount of sulfur component to be absorbed when returning to the reservoir 30 after passage. The adjusting unit 50 may estimate the amount of sulfur component by using the flow rate of the scrubber liquid per hour, the flow rate of the exhaust gas 100 flowing into the reaction tower 10 per unit time, and the amount of sulfur component contained in the exhaust gas 100 .

The adjustment unit 50 estimates the amount of sulfur component absorbed by the liquid in one circulation, and adjusts the input amount of magnesium oxide (alkaline agent) based on the estimated amount of sulfur component (step S56). The adjusting unit 50 adjusts the amount of magnesium oxide (alkaline agent) to be fed so that the estimated amount of sulfur component absorbed by the liquid in one circulation and the amount capable of neutralizing reaction are a predetermined multiple. The predetermined magnification may be, for example, a value determined within a range from 2 times to 400 times.

FIG. 8 is a flowchart showing another example of the input amount adjustment process. FIG. 8 may be a subroutine of the process of step S20 of FIG. 5 or step S42 of FIG.

The adjustment unit 50 acquires the sulfur component amount of the gas released from the reaction tower 10 during the open loop operation from the sulfur component sensor 37 (step S60). The adjustment unit 50 acquires from the storage unit 53 or the like the planned output value of the combustion device 3 that produces the exhaust gas 100 after the operation mode is switched to the closed loop operation. The adjustment unit 50 adjusts the input amount of magnesium oxide (alkaline agent) from the amount of sulfur component in the gas released from the reaction tower 10 during open-loop operation and the planned output value of the combustion device 3 during closed-loop operation ( step S64).

FIG. 9 is a flowchart showing another example of the input amount adjustment process. FIG. 9 may be a subroutine of the process of step S20 of FIG. 5 or step S42 of FIG.

The adjustment unit 50 acquires the pH of the scrubber liquid (seawater) supplied to the reaction tower 10 during open loop operation from the pH sensor 35 (step S70). The adjustment unit 50 acquires the pH of the used scrubber liquid discharged from the reaction tower 10 to the outside from the pH sensor 36 (step S72). The adjustment unit 50 acquires from the storage unit 53 or the like the planned output value of the combustion device 3 that produces the exhaust gas 100 after the operation mode is switched to the closed loop operation (step S74).

The adjustment unit 50 adjusts the pH of each of the scrubber liquid (seawater) supplied to the reaction tower 10 and the used scrubber liquid discharged from the reaction tower 10 during the open-loop operation, and the operation mode is switched to the closed-loop operation. The input amount of magnesium oxide (alkaline agent) is adjusted based on the planned output value of the combustion device 3 (step S76).

FIG. 10 is a flowchart showing another example of the input amount adjustment process. FIG. 10 may be a subroutine of the process of step S20 of FIG. 5 or step S42 of FIG.

The adjustment unit 50 acquires the amount of magnesium oxide (alkaline agent) remaining in the storage unit 30 during the previous closed mode operation (step S80). The adjusting unit 50 may adjust the amount of newly added magnesium oxide (alkaline agent) based on the amount of remaining magnesium oxide (alkaline agent).

The adjustment unit 50 may adjust the input amount adjustment by using one or more of the input amount adjustment processes in FIGS. 7 to 10 in combination.

FIG. 11 is a flowchart showing an example of cleaning processing. The control unit 51 determines whether or not the closed loop operation has switched to the open loop operation (step S90). When the closed-loop operation is switched to the open-loop operation (step S90: YES), the reservoir cleaning mechanism 38 cleans the reservoir 30 (step S92). When the closed-loop operation is switched to the open-loop operation (step S90: YES), the pipe cleaning mechanism 39 circulates the scrubber liquid between the inlet of the scrubber liquid to the reaction tower 10 and the supply port from the reservoir 30. The supply tube 34, valve 33, pump 23, and scrubber liquid tube 14 may be cleaned.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is clear from the description of the scope of the claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

The execution order of each process such as actions, procedures, steps, and stages in devices, systems, programs, and methods shown in claims, specifications, and drawings is etc., and it should be noted that they can be implemented in any order unless the output of a previous process is used in a later process. Regarding the operation flow in the claims, the specification, and the drawings, even if explanations are made using "first," "next," etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

DESCRIPTION OF SYMBOLS 1... Exhaust gas treatment apparatus 2... Exhaust gas treatment apparatus 3... Combustion apparatus 10... Reaction tower 12... Combustion gas exhaust pipe 13... Spray nozzle 14... Scrubber liquid pipe 15 Gas discharge part 16 Scrubber pipe 17 Discharge pipe 18 Valve 19 Circulation pipe 20 Valve 21 Seawater Outlet 22 Seawater intake 23 Pump 24 Seawater pipe 30 Reservoir 32 Valve 33 Valve 34 Circulating scrubber liquid Supply pipe 35 ... pH sensor 36 ... pH sensor 37 ... Sulfur component sensor 38 ... Reservoir cleaning mechanism 39 ... Pipe cleaning mechanism 40 ... Input section 50 ... adjustment unit, 51 ... control unit, 53 ... storage unit, 54 ... setting unit, 60 ... input unit, 62 ... dispensing unit, 63 ... pump, 64 ...・Storage part, 65... Pump, 100... Exhaust gas

Claims

An exhaust gas treatment apparatus capable of switching an operation mode between a closed loop operation for circulating used liquid used for exhaust gas treatment and an open loop operation for discharging the used liquid to the outside,
a reaction tower to which the exhaust gas is supplied and which purifies the exhaust gas with a liquid;
a reservoir for storing the used liquid used for purifying the exhaust gas, and supplying the used liquid whose purification ability has been restored by the alkaline agent during the closed-loop operation to the reaction tower;
an input unit for inputting the alkaline agent into the reservoir before starting to supply the used liquid from the reservoir into the reaction tower when starting the closed-loop operation;
Exhaust gas treatment device.
The exhaust gas treatment apparatus according to claim 1, wherein the charging section charges at least one of magnesium oxide and magnesium hydroxide into the storage section as the alkaline agent.
3. The exhaust gas treatment apparatus according to claim 2, wherein said charging section charges solid powder of at least one of said magnesium oxide and said magnesium hydroxide into said storage section as said alkaline agent.
The exhaust gas treatment apparatus according to any one of claims 1 to 3, wherein the charging section charges magnesium oxide into the storage section as the alkaline agent.
When the operation mode is switched to the closed-loop operation, at a first timing in the closed-loop operation, the input portion is greater than the amount of sulfur components absorbed by the liquid in one circulation and the amount that can be neutralized. 5. The exhaust gas treatment apparatus according to claim 4, wherein an amount of magnesium oxide is put into said reservoir.
The injection unit puts a smaller amount of the magnesium oxide into the storage unit than the amount injected at the first timing at a second timing after the first timing during the continuation of the closed-loop operation. The exhaust gas treatment device according to claim 5, which is replenished.
When the operation mode is switched from the open-loop operation to the closed-loop operation, the magnesium oxide is introduced into the reservoir before starting to supply the spent liquid from the reservoir into the reaction column. The exhaust gas treatment apparatus according to any one of claims 4 to 6, further comprising an adjustment unit that adjusts the amount.
The adjustment unit estimates the amount of sulfur component absorbed by the liquid in one circulation based on the output of the combustion device that generates the exhaust gas and the sulfur concentration contained in the fuel oil used in the combustion device. and adjusting the input amount based on the estimated sulfur content.
The adjustment unit adjusts the sulfur component amount of the gas discharged from the reaction tower during the open-loop operation and the planned output value of the combustion device that produces the exhaust gas after the operation mode is switched to the closed-loop operation. 8. The exhaust gas treatment apparatus according to claim 7, wherein the amount of input is adjusted based on.
The adjustment unit adjusts the hydrogen ion exponent (pH) of each of the liquid supplied to the reaction tower during the open-loop operation and the used liquid discharged from the reaction tower to the outside, and the operation mode is the closed-loop operation. 8. The exhaust gas treatment apparatus according to claim 7, wherein said input amount is adjusted based on a planned output value of a combustion device that generates said exhaust gas after being switched to .
When the operation mode is switched from the open-loop operation to the closed-loop operation, the adjustment unit adjusts the input amount based on the amount of magnesium oxide remaining in the reservoir during the previous closed-mode operation. The exhaust gas treatment device according to claim 7, which adjusts the
The exhaust gas treatment apparatus according to any one of claims 1 to 10, further comprising a reservoir cleaning mechanism that cleans the inside of the reservoir each time the operation mode is switched from the closed-loop operation to the open-loop operation.
13. Any one of claims 1 to 12, further comprising a pipe cleaning mechanism that cleans the inside of the pipe between the reaction tower and the reservoir when the operation mode is switched from the closed-loop operation to the open-loop operation. The exhaust gas treatment device according to item 1.
An exhaust gas treatment method capable of switching an operation mode between a closed loop operation for circulating the used liquid used for exhaust gas treatment and an open loop operation for discharging the used liquid to the outside,
storing the spent liquid used to purify the exhaust gas;
contacting the exhaust gas with the used liquid whose purification ability has been restored by the alkaline agent during the closed-loop operation;
and when initiating said closed-loop operation, introducing said alkaline agent into said stored used liquid prior to feeding said used liquid into contact with said exhaust gas.