KR20190051249A - Apparatus of desulfurization from marine exhaust gas using membranes - Google Patents

Abstract

The present invention relates to a desulfurization treating apparatus using a separation membrane, an exhaust gas desulfurization treating system for a ship using the same, and a treating method thereof. The exhaust gas desulfurization treating system of the present invention comprises: a desulfurization treating apparatus using a hollow fiber separation membrane including a housing, an exhaust gas inlet for introducing exhaust gas into the housing, a reactant inlet for introducing a reactant into the housing, a desulfurization reaction unit provided inside the housing, introducing the exhaust gas introduced through the exhaust gas inlet to the inside or outside of a hollow fiber separation membrane module, introducing the reactant introduced through the reactant inlet to the outside or inside of the hollow fiber separation membrane module, and absorbing and removing sulfur dioxide of the exhaust gas by the reactant, an exhaust gas discharge unit for discharging the exhaust gas in a state that a part of sulfur dioxide is removed by the desulfurization reaction unit, and a reactant discharge unit for discharging the reactant in a state that sulfur dioxide is absorbed by the desulfurization reaction unit; and a pH adjusting unit for adjusting the pH of the reactant discharged from the reactant discharge unit of the desulfurization treating apparatus to be suitable for a reference value. Also, sulfur dioxide in the exhaust gas is absorbed into seawater in a hollow fiber membrane desurfurization reaction unit, thereby finally discharging the exhaust gas reduced with sulfur dioxide from a ship.

Description

Technical Field [0001] The present invention relates to a desulfurization apparatus using a hollow fiber membrane, a desulfurization system for treating a marine exhaust gas using the hollow fiber membrane,

The present invention relates to a desulfurization apparatus using a separation membrane, a desulfurization system for a ship exhaust gas using the desulfurization apparatus, and a treatment method. And more particularly, to an exhaust gas desulfurization apparatus for desulfurizing sulfur oxides, which are major air pollutants in exhaust gas discharged from a ship or the like, using a separation membrane.

In recent years, environmental pollution problems have arisen due to the exhaust gas discharged from vessels in addition to the fixed discharge equipment on the land, automobiles, and so much attention has been paid to exhaust gas treatment methods. More than 85% of world trade is done by sea transportation, which causes emissions of 3 to 7% of SOx, 2.5 to 4% of global warming gas, 15% of NOx, over 5% of all carbon emissions, Is expected to increase by 50 ~ 250% by 2050. 70% of these maritime transports are within 400 km of the coast and can be more threatening to mankind. In the 70th session of the marine environment protection committee (IMO) of the International Maritime Organization (IMO), for the purpose of regulating greenhouse gas emissions, ships with a capacity of more than 5,000 ton Time, and so on. Accordingly, the ship shall submit the data to the IMO Central Database after confirming the conformity of the data to be added to the country of the ship in the yearly basis.

At the 70th session of the MEPC, it was decided to regulate the content of fuel sulfur oxides used in ships to less than 0.5% from 2020. Sulfur contained in the fuel is converted to sulfur oxides (SOx) during combustion, and if released into the atmosphere, it causes acid rain and harms human health. Accordingly, in order to satisfy the strengthened international sulfur oxides regulations, shipbuilders have been forced to take measures such as using low sulfur oil or LNG as main fuel for ships or installing additional sulfur reduction equipment. In general, wet scrubber technology is typically used as a sulfur reduction device in exhaust gas from ships, and they are classified into open type and closed type.

In the open scrubber system, the neutralization reaction is carried out through exhaust gas cleaning using naturally alkaline seawater, thereby reducing sulfur oxides and particulate matter. In addition, the seawater discharged from the scrubber after the neutralization reaction is subjected to pH adjustment process to prevent marine pollution, and then discharged to the sea outside the ship.

The closed scrubber is a method for reducing the particulate matter by neutralization reaction and reducing the particulate matter by cleaning the exhaust gas using an aqueous solution of the reactant in which fresh water and a neutralization reactant are mixed, The aqueous solution is prepared by adding sodium hydroxide (NaOH) solution to clear water (fresh water). The heat generated in this process is cooled by seawater and the cooled aqueous solution of the reactant is supplied to the washing tower for use in the exhaust gas cleaning. After the washing, some of the solution discharged from the washing tower is centrifuged and pH adjusted, And most of the remaining solution is recycled by adding an alkali reagent for cleaning the exhaust gas.

Using this scrubber, exhaust gas desulfurization method requires additional power of 50 ~ 700kW with the cost of facility investment of $ 10 ~ 10million per ship according to engine power compared with the method of using low-sulfur oil as main fuel for ship . Also, the back pressure may increase due to the scrubber installed on the exhaust pipe, which may degrade the engine performance, which may increase fuel consumption.

The use of low-sulfur oil as the main fuel for the ship is considered to be the simplest way to meet the ship's SOx regulations because no additional equipment is required. At present, however, the price of low sulfur oil is 40 ~ 80% higher than that of unique sulfur oil. Furthermore, since the sulfur content varies depending on the production method of the rectifier, caution is required when using it. For this reason, it is estimated that the most economical method is to install additional scrubber as the most stable countermeasure to meet SOx regulations. However, when the scrubber is installed and operated, the cost of operating the vessel by the reduction of the cargo space for storing the neutralizing reaction alkali and the treated water used for the exhaust gas cleaning and fuel consumption is increased, and the problem of the sludge treatment And corrosion of piping lines, there is an urgent need to develop new technologies for desulfurization of ships.

Patent Document 10-1630074 (Ship Emission Gas Desulfurization Apparatus) for an existing marine exhaust gas desulfurization apparatus is related to a marine exhaust gas desulfurization apparatus. In exhaust gas treatment, exhaust gas is firstly pretreated by wet ozone, Which is capable of improving the treatment efficiency of sulfur oxides.

Further, in a ship exhaust gas desulfurization apparatus for desulfurizing an exhaust gas using seawater, the exhaust gas desulfurization apparatus for a ship is provided with a gas supply pipe through which the exhaust gas flows and a discharge pipe through which the exhaust gas is discharged Body; A pivoting unit for pivoting the exhaust gas flowing into the body; A dissolution processor for passing the exhaust gas into the seawater; A collection processing unit having a filling material for collecting contaminants of the exhaust gas; A spray tube for spraying and supplying the seawater to the swirling processing section, the dissolution processing section, and the collecting processing section; And a discharge pipe for discharging the seawater to the swirling treatment section, the dissolution treatment section, and the collecting treatment section, wherein the seawater of the spray pipe is supplied directly from the sea, and the seawater of the discharge pipe may not be reused .

The present invention also relates to an apparatus for treating exhaust gas discharged from a marine diesel engine using ozone, hydrogen peroxide, and a neutralizing agent. The apparatus is provided with an air flow distribution perforated plate The ozone treatment, the hydrogen peroxide treatment and the neutralization treatment are independently performed in the partitioned reaction space, so that each reaction can be performed more efficiently under the uniform distribution condition of the exhaust gas flow, while the ammonium salt The present invention relates to a desulfurization / denitration apparatus for marine exhaust gas, which is capable of improving the recovery rate and the recycling rate of ammonium salts by collecting the exhaust gas from the dust collector through a drain pipe provided at the bottom of the reaction tank.

Korea Patent No. 1630074 Korean Patent Publication No. 2015-0024071 Korea Patent No. 1117677

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a desulfurization apparatus for treating sulfur dioxide in marine exhaust gas more economically and economically, By flowing seawater to the inside or outside of the hollow fiber membrane module and flowing the exhaust gas from the ship on the opposite side, sulfur dioxide in the exhaust gas is absorbed into seawater by the contact of gas and liquid at the interface of the hollow fiber membrane, And to provide a desulfurization apparatus and a system therefor. have.

According to the one embodiment of the present invention, there is no need for a neutralization process of the exhaust gas. Therefore, the facilities and neutralizing agent necessary for the neutralization treatment in the existing scrubber desulfurization apparatus are not needed, The goal is to provide a technology that can be

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

A first object of the present invention is to provide a desulfurization apparatus comprising: a housing; An exhaust gas inlet configured to introduce exhaust gas into the housing; A reactant inlet configured to introduce a reactant into the housing; The exhaust gas introduced into the interior of the housing through the exhaust gas inlet portion flows into the interior or the exterior of the hollow fiber membrane module and the reactant introduced through the reactant inlet portion flows outside or inside the hollow fiber membrane module A desulfurization reaction unit to which the reactant absorbs and removes the oxidation reaction of the exhaust gas; An exhaust gas discharging portion through which exhaust gas in a state in which sulfur dioxide is partially removed from the desulfurization reaction portion is discharged; And a reactant discharging portion through which the reactant is discharged from the desulfurization reaction portion in a state where sulfur dioxide is absorbed. The desulfurization treatment device using the hollow fiber separation membrane can be achieved.

The separation membrane module includes a separation membrane casing having a separation membrane, one end closed, a through hole through which reactants can move at both ends, and the other end connected to a reaction agent discharge part through which the reactant absorbing sulfur dioxide is discharged. A first opening formed in one end portion of the separation membrane casing and extending in the longitudinal direction of the separation membrane casing, the first separation membrane casing having a first communication space, 1 communication casing; And a second communication hole formed in the other end of the separation membrane casing so as to communicate with the second separation hole and the through hole, the second communication hole being formed around the outer circumference of the separation membrane casing and opened in the longitudinal direction of the separation membrane casing And a first communication casing arranged to penetrate the reactant inlet portion, wherein the plurality of the separation membrane modules are connected to each other by a first communication case adjacent to the first communication case, And a gap may be formed between the separation membrane casings.

The separation membrane may be formed of a plurality of hollow fiber membranes.

The separation membrane is a flat membrane, and a flat membrane spacer in which a pair of flat membranes are disposed on both sides and a supply spacer in which a fluid moves inside are wound around a center tube having a separation hole formed therein, And is connected to only the flat membrane spacer.

A second object of the present invention is to provide a desulfurization treatment method comprising the steps of introducing an exhaust gas into an exhaust gas inflow portion through a exhaust gas inflow portion and introducing the reactant into a housing through a reactant inflow portion; The exhaust gas flowing through the exhaust gas inflow portion flows into or out of the hollow fiber separation membrane module of the desulfurization reaction portion and the reactant introduced through the reactive agent inflow portion flows into the hollow fiber separation membrane module or into the interior thereof, Absorbing and removing sulfur dioxide of the exhaust gas; And exhausting the exhaust gas in a state where sulfur dioxide is partially removed from the desulfurization reaction unit through the exhaust gas discharge unit and discharging the reactant through the reaction agent discharge unit in a state where sulfur dioxide is absorbed from the desulfurization reaction unit As a desulfurization treatment method using a hollow fiber membrane.

A third object of the present invention is to provide a desulfurization system comprising: a desulfurization apparatus using a separation membrane according to the first object; And a pH adjusting unit adjusting the pH of the reactant discharged from the reactant discharging unit of the desulfurization apparatus to a standard value.

The exhaust gas may be a marine exhaust gas, and the reactant may be seawater.

A gas pressure regulator provided at one side of the exhaust gas inflow part to regulate the pressure of the exhaust gas flowing into the desulfurization device; And a reaction pressure regulator for regulating the pressure of the reaction gas.

The controller may further include a controller for controlling the gas pressure regulator and the reactant pressure regulator such that a pressure applied to the reactant is higher than a pressure applied to the exhaust gas.

The apparatus may further include a pH measuring unit for measuring a pH of the reactant discharged through the reactant discharging unit in real time.

The pH adjusting unit may include a seawater mixer into which the reactant discharged through the reactant discharging unit flows; And a control unit for controlling the seawater supply means to control the pH of the reactant to be higher than the reference value if the pH value measured by the pH measuring unit is lower than a predetermined reference value, Or more.

A fourth object of the present invention is to provide a desulfurization treatment method for a marine exhaust gas, comprising the steps of introducing marine exhaust gas through an exhaust gas inflow section into a housing and introducing seawater as a reactant into a housing through a reactant inflow section; The exhaust gas flowing through the exhaust gas inflow portion flows into or out of the hollow fiber separation membrane module of the desulfurization reaction portion and the reactant introduced through the reactive agent inflow portion flows into the hollow fiber separation membrane module or into the interior thereof, Absorbing and removing sulfur dioxide of the exhaust gas; Exhausting the exhaust gas in a state where sulfur dioxide is partially removed from the desulfurization reaction unit through the exhaust gas discharge unit and discharging the reactant through the reaction agent discharge unit in a state where sulfur dioxide is absorbed from the desulfurization reaction unit; And adjusting the pH of the reaction agent so that the pH of the reactant discharged from the reactant discharge portion of the desulfurization treatment device is adjusted to a standard value. The desulfurization treatment method for a ship exhaust gas using a hollow fiber membrane have.

The gas pressure regulator provided at one side of the exhaust gas inflow part adjusts the pressure of the exhaust gas flowing into the desulfurization device, and the reactant pressure regulator provided at one side of the reactant inlet part flows into the desulfurization device And adjusting the pressure of the reactive agent.

The control unit may control the gas pressure regulator and the reactant pressure regulator such that a pressure applied to the reactant is higher than a pressure applied to the exhaust gas.

And measuring the pH of the reactant discharged through the reactant discharging unit in real time by the pH measuring unit, wherein the step of adjusting the pH to meet the reference value comprises: Mixer, and when the pH value measured by the pH measuring unit is equal to or less than a set reference value, the control unit controls the seawater introducing unit to introduce seawater into the seawater mixer to adjust the pH of the reagent to be equal to or greater than the reference value .

According to one embodiment of the present invention, when seawater is used as a liquid and a gaseous exhaust gas is flowed into the hollow fiber membrane, the sulfur dioxide gas contained in the exhaust gas is absorbed into the seawater due to the role of a gas- .

In addition, according to the desulfurization apparatus according to an embodiment of the present invention, not only sulfur dioxide but also water-soluble gas such as carbon dioxide can be reduced as well, thereby reducing greenhouse gas emissions from the whole point of view.

In addition, in an embodiment of the present invention, since facilities (scrubbers, neutralizers, etc.) in the existing scrubber desulfurization apparatus are not needed, there is also an effect that the cost efficiency is increased and the cost is reduced. Such a hollow fiber membrane desulfurization device may be installed solely on a newly constructed vessel. However, it can be installed on existing ships. As mentioned above, since 2020, it is necessary to reduce the content of sulfur oxides to less than 0.5%. For this purpose, additional desulfurization equipment is required, and it is also possible to install a desulfurization apparatus for hollow fiber membrane here.

It should be understood, however, that the effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present invention belongs It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be construed as limited.
FIG. 1 and FIG. 2 are views showing a configuration of a desulfurization system for marine exhaust gas using a hollow fiber membrane according to an embodiment of the present invention,
3 is a block diagram of a marine exhaust gas desulfurization system using a hollow fiber membrane according to an embodiment of the present invention.
4 is a block diagram illustrating a signal flow according to a control unit of a desulfurization system for marine exhaust gas using a hollow fiber membrane according to an embodiment of the present invention.
5, 6, and 7 are perspective views of a hollow fiber membrane desulfurization reaction unit constructed of a separation membrane module,
8 is a partial cutaway perspective view of the separation membrane module
Fig. 9 is an exploded perspective view of Fig.
Figure 10 is a cross-
11 is a perspective view showing a state in which a separation membrane module is stacked
Fig. 12 is a partially cutaway perspective view of Fig.
13 is an exploded perspective view of Fig. 12
14 is a perspective view showing a separation membrane module of a rectangular shape
15 is a graph showing the SO ₂ removal efficiency and pH change using water as a reactant according to the experimental example of the present invention
16 is a graph showing the SO ₂ removal efficiency and pH change using seawater as a reactant according to the experimental example of the present invention
17 is a graph showing the SO ₂ removal efficiency comparison graph using seawater and U as a reactant according to the experimental example of the present invention
FIG. 18 is a graph showing the SO ₂ removal efficiency according to the membrane area according to the experimental example of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Also in the figures, the thickness of the components is exaggerated for an effective description of the technical content.

Embodiments described herein will be described with reference to cross-sectional views and / or plan views that are ideal illustrations of the present invention. In the drawings, the thicknesses of the films and regions are exaggerated for an effective description of the technical content. Thus, the shape of the illustrations may be modified by manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in the shapes that are produced according to the manufacturing process. For example, the area shown at right angles may be rounded or may have a shape with a certain curvature. Thus, the regions illustrated in the figures have attributes, and the shapes of the regions illustrated in the figures are intended to illustrate specific forms of regions of the elements and are not intended to limit the scope of the invention. Although the terms first, second, etc. have been used in various embodiments of the present disclosure to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. The embodiments described and exemplified herein also include their complementary embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms "comprises" and / or "comprising" used in the specification do not exclude the presence or addition of one or more other elements.

In describing the specific embodiments below, various specific details have been set forth in order to explain the invention in greater detail and to assist in understanding it. However, it will be appreciated by those skilled in the art that the present invention may be understood by those skilled in the art without departing from such specific details. In some instances, it should be noted that portions of the invention that are not commonly known in the description of the invention and are not significantly related to the invention do not describe confusing reasons to explain the present invention.

Hereinafter, the structure and function of the exhaust gas desulfurization system for marine vessel 1 using the hollow fiber membrane according to one embodiment of the present invention will be described. FIG. 1 and FIG. 2 show a configuration diagram of a marine exhaust gas desulfurization system 1 using a hollow fiber membrane according to an embodiment of the present invention. 3 is a block diagram of a marine exhaust gas desulfurization system 1 using a hollow fiber membrane according to an embodiment of the present invention. 4 is a block diagram showing a signal flow according to the control unit 400 of the exhaust gas desulfurization system for marine vessel 1 using a hollow fiber membrane according to an embodiment of the present invention.

As shown in FIGS. 1, 2 and 3, the exhaust gas desulfurization system 1 for a ship using a hollow fiber membrane according to an embodiment of the present invention includes a desulfurization apparatus 200 having a hollow fiber membrane as a whole, The exhaust gas outlet 20, the reactant inlet 30, the reactant outlet 40, the pH controller 300, and the like.

The exhaust gas inlet 10 is configured to introduce exhaust gas into the housing and the reactant inlet 30 is configured to allow reactants to flow into the housing. The desulfurization reaction unit composed of a separation membrane is provided inside the housing and the exhaust gas flowing through the exhaust gas inlet unit 10 flows into the inside or the outside of the hollow fiber membrane module, The reactant flows into the hollow fiber membrane module or the inside of the hollow fiber membrane module, and the reactant absorbs and removes the oxidation agent of the exhaust gas.

The exhaust gas discharged from the desulfurization reaction unit in a state in which sulfur dioxide is partially removed is discharged from the exhaust gas discharge unit 20 and the reactant is discharged from the desulfurization reaction unit in a state where sulfur dioxide is absorbed from the desulfurization reaction unit .

As shown in FIGS. 1 and 2, the liquid reactant and the gaseous exhaust gas injected into the desulfurization reaction unit constituted by the hollow fiber membrane module can be injected into either.

Accordingly, the exhaust gas flows into the housing through the exhaust gas inlet 10, and the reactant flows into the housing through the reactant inlet 30. As shown in FIG. 1, the exhaust gas may be introduced into the desulfurization reactor through the exhaust gas inlet 10, or may be introduced into the desulfurization reactor, do. 1, when the exhaust gas flows into the desulfurization reaction unit constituted by the separation membrane module through the exhaust gas inlet 10, the liquid reaction agent flows through the reactive agent inlet 30, And then flows into the outside.

The exhaust gas flowing through the exhaust gas inflow section 10 flows into the inside or outside of the hollow fiber separator module of the desulfurization reaction section and the reactant flowing through the reactive agent inflow section 30 flows to the outside of the hollow fiber separation membrane module Or the like, so that the reactant absorbs and removes sulfur dioxide of the exhaust gas.

Exhaust gas in a state in which sulfur dioxide is partially removed from the desulfurization reaction unit is exhausted through the exhaust gas exhaust unit 20. In the state where the sulfur dioxide is absorbed from the desulfurization reaction unit, .

According to an embodiment of the present invention, a marine exhaust gas is connected to a desulfurization apparatus 200 composed of a microporous hollow fiber membrane module to flow into or out of the hollow fiber membrane, and the exhaust gas from the opposite side The seawater flows into the outside, and when the exhaust gas is outside the module, the seawater flows into the inside), thereby removing the sulfur dioxide present in the exhaust gas.

A porous hollow fiber membrane made of a polymer such as polypropylene or polyethylene has a hydrophobic property. When the liquid water is contacted to one side of the hollow fiber membrane or the outside thereof and the exhaust gas containing sulfur dioxide is brought into contact with the other side Although the seawater can not pass through the micropores, water-soluble gases such as sulfur dioxide can pass through it, and the sulfur dioxide gas passing through the pores is absorbed by the seawater. Using this principle, the sulfur dioxide gas can be separated from the exhaust gas through the microporous hollow fiber membrane.

Such a gas-absorbing hollow fiber membrane has an advantage that it can artificially control the contact between the gas and the liquid as the absorbent. In other words, the gas and liquid flow can be controlled independently, have a very large gas-liquid contact area compared to other processes, and there are advantages of easy scale-up. Therefore, the performance of sulfur dioxide removal efficiency using hollow fiber membranes depends on the membrane material, the physico-chemical properties of the absorbent, the pore size of the membrane, the porosity of the membrane, the operating conditions of the system (gas pressure, liquid flow rate, And the operation mode depending on whether it is filled with a liquid or a liquid.

Since the membrane used in the ship desulfurization apparatus should not have the liquid (hydrophilic) passing over to the gas side, it is preferable to use a polymer having a hydrophobic property, and the larger the hydrophobic property is, the larger the liquid pressure can be applied, . In addition, since the pore size existing inside the membrane is small and uniformly distributed and the porosity is large, the gas-liquid contact area is widened, which is preferable for the performance improvement.

The desulfurization system 1 for marine exhaust gas using the hollow fiber membrane according to an embodiment of the present invention may further include a pH controller 300 for adjusting the pH of the reactant, ).

Drainage from ships should be environmentally friendly. In order to ensure that the ship's drainage does not contaminate the oceans, the water exiting the ship is prescribed by the EPA and the IMP to ensure that the acute mixture boundary pH value should reach 6.5 within 15 minutes. In the desulfurization apparatus of the present invention, seawater is used to remove sulfur dioxide. Since the seawater absorbing sulfur dioxide changes to be acidic, it is necessary to increase the pH value in order to discharge the effluent to the natural waters.

However, the general pH of fresh water is 7.0, but the pH range of seawater is 7.4 ~ 8.4, and the average pH is about 8, which is weak basicity. For this reason, sodium chloride (NaCl), magnesium chloride (MgCl), magnesium sulfate (MgSO ₄ ), calcium sulfate (CaSO ₄ ), sodium bromide (NaBr), potassium chloride (KCl) and calcium carbonate (CaCO ₃ ) do. When these components are dissolved in water, anions (Cl-, SO ₄ ^2- , Br ^- , CO ₃ ^2- ) are formed. These anions are bound to hydrogen cations (H ⁺ ) in a small ratio, Is derived from the equilibrium hydrogen cations separated from the water molecules in the water. Thus, as the hydrogen cation concentration decreases, the pH becomes higher. In addition, for equilibrium, water is constantly dissociated into hydrogen cations and hydroxide anions (OH ^- ), where the dissociated hydroxide anions increase the total hydroxide ion concentration in the water, further increasing the pH.

Therefore, it has a feature that the pH is not lowered much even if it absorbs sulfur dioxide compared to general fresh water. Furthermore, as shown in the experimental results of the examples, the effluent after absorbing sulfur dioxide showed a higher pH value in the range of 1.55 to 1.58 than that of normal fresh water. This is probably due to the fact that the initial state of seawater is about 1 higher in pH than freshwater and that alkaline ions present in the seawater act as a buffer for the absorption of sulfur dioxide.

The present invention includes a pH adjusting unit 300 for quickly raising the pH of the effluent to a level higher than a reference level by mixing and diluting new alkaline seawater at the downstream end of the effluent to reach the pH of the effluent within 6.5 minutes.

A gas pressure regulating part 11 provided at one side of the exhaust gas inflow part 10 to regulate the pressure of the exhaust gas flowing into the desulfurization device 200; And a reactant pressure regulator 31 for regulating the pressure of the reactant flowing into the desulfurizer 200.

4, the control unit 400 controls the gas pressure regulator 11 and the reactant pressure regulator 31 so that the pressure applied to the reactant is higher than the pressure applied to the exhaust gas, .

The pH measuring unit 310 may measure the pH of the reactant discharged through the reactant discharging unit 40 in real time. The pH adjusting unit 300 includes a seawater mixer 320 into which the reactant discharged through the reactant discharging unit 40 is introduced and a seawater introducing unit 330 through which the seawater is introduced into the seawater mixer 320 Lt; / RTI >

4, when the pH measured by the pH measuring unit 310 is lower than a predetermined reference value, the control unit 400 controls the seawater input unit 330 so that the pH of the reactant is lower than the reference value .

Accordingly, in the method for desulfurizing the marine exhaust gas, the marine exhaust gas flows into the housing through the exhaust gas inlet portion 10, and the sea water, which is a reactant, flows into the housing through the reactant inlet portion 30.

The exhaust gas flowing through the exhaust gas inflow section 10 flows into the inside or outside of the hollow fiber separator module of the desulfurization reaction section and the reactant flowing through the reactive agent inflow section 30 flows to the outside of the hollow fiber separation membrane module Or the like, so that the reactant absorbs and removes sulfur dioxide of the exhaust gas.

Exhaust gas in a state in which sulfur dioxide is partially removed from the desulfurization reaction unit is exhausted through the exhaust gas exhaust unit 20. In the state where the sulfur dioxide is absorbed from the desulfurization reaction unit, .

In addition, the pH adjusting unit 300 adjusts the pH of the reactant discharged from the reactant discharging unit 40 of the desulfurization apparatus 200 to a reference value.

The gas pressure regulating part 11 provided at one side of the exhaust gas inflow part 10 regulates the pressure of the exhaust gas flowing into the desulfurization device 200, The reactor pressure regulator 31 regulates the pressure of the reactant flowing into the desulfurizer 200.

The control unit 400 controls the gas pressure regulator 11 and the reactant pressure regulator 31 so that the pressure applied to the reactant is higher than the pressure applied to the exhaust gas.

The pH measuring unit 310 measures the pH of the reactant discharged through the reactant discharging unit 40 in real time and adjusts the pH to be suitable for the reference value. The discharged reactant flows into the seawater mixer 320. When the pH value measured by the pH measuring unit 310 is lower than a predetermined reference value, the control unit 400 controls the seawater input unit 330 to control the seawater mixer 320) to adjust the pH of the reactant to be equal to or greater than the reference value.

Hereinafter, the structure of the hollow fiber membrane desulfurization reaction unit comprising the separation membrane module according to the embodiment of the present invention will be described. FIGS. 5, 6, and 7 show a perspective view of a hollow fiber membrane desulfurization reaction unit constructed of a separation membrane module.

5 is a perspective view of a desulfurization apparatus 200 constructed with a separation membrane module according to a first embodiment of the present invention. 5, the separation membrane module 210 includes a plurality of hollow fiber membranes 211 and connectors 212 disposed at both ends of the hollow fiber membranes 211. The connector 212 communicates with the interior of the hollow fiber membrane 211. Accordingly, when the connector 212 is communicated with the negative pressure chamber, the negative pressure chamber 270 can communicate with the inside of the hollow fiber membrane 211. Accordingly, the negative pressure chambers 270 may be provided on the upper and lower sides of the housing 201, as shown in FIG. 5, and may be connected to each other.

The hollow fiber membrane 211 is formed by cutting a polymer membrane fiber (hereinafter referred to as a hollow fiber membrane 211) having a structure such as a hollow fiber having excellent selectivity against moisture to a predetermined length. A plurality of such hollow fiber membranes 211 The connector module 212 is configured to have a cluster shape uniformly distributed thereon, and both ends thereof are fixed and modularized to constitute a separation membrane module. The separating membrane module 210 does not necessarily comprise a plurality of connectors, and the negative pressure chamber 270 is not necessarily constituted by the hollow fiber membrane 270 and the negative pressure chamber 270 capable of applying a negative pressure to the inside of the hollow fiber membrane and the hollow fiber membrane. It is also possible to place them at both ends of the clustered hollow fiber membrane 211.

7 is a perspective view of a desulfurization apparatus 200 constructed with a separation membrane module according to a second embodiment of the present invention. 7, the shape of the housing 201, the negative pressure chamber 270, and the separation pipe 271 of the desulfurization apparatus 200 according to the second embodiment is the same as that of the desulfurization apparatus 200 according to the first embodiment 200, but there is a difference in that all of the connectors 212 provided at both ends of the hollow fiber membrane 211 communicate with the negative pressure chamber 270.

8 is a partially cutaway perspective view of a separation membrane module applied to the desulfurization apparatus 200 according to the third embodiment of the present invention. Fig. 9 is an exploded perspective view of Fig. 8, and Fig. 10 is a sectional view of Fig. 11 is a perspective view showing a state in which the separation membrane module according to the third embodiment of the present invention is laminated.

The desulfurization apparatus 200 according to the third embodiment of the present invention includes a plurality of separation membrane modules and a negative pressure chamber 270 connected to the plurality of separation membrane modules. As shown in FIGS. 8 and 9, the separation membrane module includes a separation membrane casing 220 disposed at a central portion and having a plurality of hollow fiber membranes 211 embedded therein, and a first communication case 220 disposed at both ends of the separation membrane casing 220. [ (230) and a second communication casing (240).

The hollow fiber membrane 211 is the same as the hollow fiber membrane 211 described in the first and second embodiments. One end of the separation membrane casing 220 is closed and a separation fluid supply pipe 260 is connected to the other end thereof. One end of the separation membrane casing 220 may be closed by a sealing cover 234, or the separation membrane casing 220 may have a tube shape in which one end is closed and the other end is opened. At both ends of the separation membrane casing 220, through-holes through which fluids can move are formed, respectively. The first communication case 230 and the second communication case 240 are respectively installed on the first installation surface 221 and the second installation surface 224 where the through holes are formed.

As shown in FIG. 8, the through-holes are radially formed along the circumferential surface of the separation membrane casing 220, and a plurality of the through-holes are arranged along the longitudinal direction of the separation membrane casing 220, .

The first communication casing 230 is installed around the first installation surface 221 at one end of the separation membrane casing 220 and has a first opening hole 232 opened in the longitudinal direction of the separation membrane casing 220 Is formed. As a result, a first communication space 231 for communicating the first opening 232 with the through hole is formed.

The separation membrane casing 220 is inserted into one side of the first communication casing 230 and the first insertion hole 233 is fixed to the outer circumference of the separation membrane casing 220.

The cover 234 may be coupled to the screw portion 223 formed in the separation membrane casing 220 by various methods such as screwing, fitting, or welding. Or may be coupled to one end of the separation membrane casing 220 while being integrally fixed to the first communication casing 230.

The second communication casing 240 is installed around the second installation surface 224 at the other end of the separation membrane casing 220 and includes a second opening hole 242 are formed. As a result, a second communication space 241 for communicating the second through hole 242 with the first through hole 222 is formed.

The separation membrane casing 220 is inserted into one side of the second communication casing 240 and a second insertion hole 243 is formed to be fixed to the outer circumference of the separation membrane casing 220. The reactant inlet (30) is protruded and extended through the second opening (242) of the second communication casing (240).

The reactant inlet 30 may be coupled to the screw portion 223 formed in the separation membrane casing 220 by various methods such as screwing, fitting, or welding.

The flow path of the fluid in the separation membrane module constituting the desulfurization apparatus 200 according to the first embodiment will be described as follows. First, the reactant, which is fluid through the first communication casing 230, flows into the first through-hole 222 via the first communication space 231. 10, the sulfur dioxide of the exhaust gas is absorbed by the hollow fiber membrane 211 while passing through the air gap around the hollow fiber membrane 211, as shown in FIG. 10, The reactant absorbed by sulfur dioxide is discharged through the second through-hole 225 on the other side through the second communication space 241 of the second communication case 240.

As a result, since the fluid flows in the longitudinal direction of the separator module 210 and is discharged in the longitudinal direction of the separator module 210, the flow direction of the fluid has the same directionality before and after the flow.

11 is a view illustrating a structure of the desulfurization apparatus 200 by stacking the separation membrane casing 220. The first communication casing 230 and the second communication casing 240 have a polygonal cross section , More preferably a rectangle or a square.

12 is a partially cutaway perspective view of a separation membrane module according to a fourth embodiment of the present invention. Fig. 13 shows a sectional view of Fig. 12. Fig.

The separation membrane module according to the fourth embodiment of the present invention uses a flat membrane 251, unlike the separation membrane module according to the first to third embodiments.

The separation membrane module 210 includes a separation membrane casing 220 in which a flat membrane assembly 250 is installed and a first communication casing 230 and a second communication casing 220 disposed at both ends of the separation membrane casing 220, 240).

The flat membrane assembly 250 includes a flat membrane spacer 255 on both sides of which a pair of flat membranes 251 are disposed and a supply spacer 254 through which a fluid moves inside the flat membrane assembly 250, Is wound around the center tube (252) formed thereon. At this time, the center pipe 252 is only communicated with the flat membrane spacer 255.

The flat membrane 251 may be a flat membrane according to a known technique, and a detailed description thereof will be omitted. Also, the feed spacer 254 and the flat spacer 255 may be spacers known in the art.

One end of the separation membrane casing 220 is closed and a separation fluid supply pipe 260 is connected to the other end thereof. One end of the separation membrane casing 220 may be closed by a sealing cover 234, or the separation membrane casing 220 may have a tube shape in which one end is closed and the other end is opened. A through hole 222 is formed at one end of the separation membrane casing 220 and a through cover 256 having a second through hole 225 is connected to the other end of the separation membrane casing 220. The second through hole 225 is disposed close to the center pipe 252 and the center of the through cover 256 is disposed to communicate with the center pipe 252. The first communication casing 230 and the second communication casing 240 are installed at both ends of the separation membrane casing 220.

As shown in FIG. 13, the first through-holes 222 are radially formed along the circumferential surface of the separation membrane casing 220, and a plurality of the first through-holes 222 are disposed along the longitudinal direction of the separation membrane casing 220, To be uniformly introduced. Further, a plurality of the second through holes 225 are radially arranged in the vicinity of the center tube 252. As a result, a sufficient residence time for the fluid that has passed through the first through-hole 222 to be separated by the flat membrane 251 and moved to the flat membrane spacer 255 via the feed spacer 254, The contact area between the contact surface and the contact surface can be provided.

The first communication casing 230 is installed around the first installation surface 221 at one end of the separation membrane casing 220 and includes a first opening hole 232 are formed. As a result, a first communication space 231 for communicating the first opening 232 with the through hole is formed.

The separation membrane casing 220 is inserted into one side of the first communication casing 230 and the first insertion hole 233 is fixed to the outer circumference of the separation membrane casing 220. The sealing cover 234 may be coupled to the screw portion 223 formed on the separation membrane casing 220 by various methods such as screwing, fitting, or welding. Or may be coupled to one end of the separation membrane casing 220 while being integrally fixed to the first communication casing 230.

The second communication case 240 is installed at the other end of the separation membrane casing 220 and has a second opening 242 opened in the longitudinal direction of the separation membrane casing 220. As a result, a second communication space 241 for communicating the second through hole 242 and the second through hole 225 is formed.

The separation membrane casing 220 is inserted through the second insertion hole 243 and fixed to one side of the second communication casing 240. Therefore, the surfaces of the second communication space 241 and the separation membrane casing 220 which are not inserted into the first and second communication casings 240 are exposed from the first and second communication spaces 241, . The separated fluid supply pipe 260 protrudes and extends through the second opening hole 242 of the second communication casing 240.

The separate fluid supply pipe 260 may be coupled to the penetration cover 256 by various methods such as screwing, fitting, or welding.

The path of the air of the separation membrane module 210 configured as described above will be described as follows.

First, the fluid flows into the through-hole through the first communication space 231 through the first communication casing 230. 13 and 14, the fluid that flows into the interior of the separation membrane casing 220 flows from the outer circumferential side to the center side of the supply spacers 254 of the separation membrane assembly 250, 251 absorbs the desired sulfur dioxide as the reactant and the reactant absorbing the sulfur dioxide passes through the second through-hole 225 through the center tube 252 having the separation hole 253, 240 to the clean chamber side via the second communication space 241. [

[Experimental Example]

FIG. 15 is a graph showing SO ₂ removal efficiency and pH change using water as a reactant according to Experimental Example of the present invention. 16 is a graph showing SO ₂ removal efficiency and pH change using seawater as a reactant according to Experimental Example of the present invention. 17 is a graph showing a comparative SO ₂ removal efficiency using seawater and phosphorus as a reactant according to an experimental example of the present invention. 18 is a graph showing the SO ₂ removal efficiency according to the membrane area according to the experimental example of the present invention.

In the experimental example of the present invention, a hollow fiber membrane module having a hollow fiber membrane module having a different effective hollow fiber membrane area was manufactured by changing the number of polypropylene hollow fiber membranes in a cylindrical module having a diameter of 2.54 cm and an effective length of 30 cm, and these modules were installed in a sulfur dioxide separation system. , The kind of reactant (water, seawater), the area of hollow fiber membrane, and so on. The liquid reactant flows into the hollow fiber membrane, and a gas containing sulfur dioxide is flowed to the outside of the hollow fiber membrane.

Fig. 15 is a graph showing the relationship between the flow rate of the sulfur dioxide gas and the reactant liquid pressure when the module having an effective area of 0.29 m < ² > is connected to the sulfur dioxide separation system, 0.5 bar, and then the sulfur dioxide removal efficiency and the pH of the reactant containing sulfur dioxide after the reaction were measured. As the gas pressure increased, the sulfur dioxide removal efficiency gradually increased and the removal efficiency was 93.8% at the gas pressure of 2.92 bar. Since the sulfur dioxide thus removed is contained in the reactant, the reactant gradually changes to acidic, and accordingly the pH value is gradually decreased as the sulfur dioxide removal efficiency is increased.

FIG. 16 shows the result of measuring sulfur dioxide removal efficiency and pH value by changing only the reactant from water to sea water in the experiment of FIG. The sea water was dissolved in water and the sea salts reagent purchased from Sigma-Aldrich was made equal to the concentration of sea water. As the gas pressure increased, the removal efficiency of sulfur dioxide gradually increased and the removal efficiency was 94.3% when the gas pressure was 2.48 bar. As the gas pressure increased, the pH value gradually decreased. When the water was used as the reactant, the pH value ranged from 3.07 to 2.98. However, when the sea water was used as the reactant, the pH was in the range of 4.65 to 4.53. Respectively. The average pH of the seawater is 8.0, which is about 1.0 higher than the pH of the fresh water. In addition, the alkaline ions present in the seawater acted as a buffer for the absorption of sulfur dioxide, resulting in higher sulfur dioxide removal efficiency.

FIG. 17 is a graph in which only the sulfur dioxide removal efficiency is separated from the results of FIGS. 15 and 16. As shown in Figure 17, at the same gas pressure, the sulfur dioxide removal efficiency for seawater reactants was 2.8-0.8% higher than the sulfur dioxide removal efficiency for water reactants. Unusual was that the lower the gas pressure, the higher the sulfur dioxide removal efficiency for the seawater reactants was than the sulfur dioxide removal efficiency for the water reactants. Therefore, it can be confirmed that it is more effective to use seawater as a reactant rather than water in order to increase the sulfur dioxide removal efficiency while keeping the gas pressure low (low energy consumption).

18 shows the results of evaluating the performance of a module having different effective areas (0.16, 0.23, 0.29 m ² ) by using water as a reactant and controlling the number of hollow fiber membranes. As the hollow fiber membrane area increased, the sulfur dioxide removal efficiency increased. From this, it was found that the sulfur dioxide removal efficiency could be further increased by increasing the effective hollow fiber membrane area. Based on these results, it is possible to calculate the effective area of the hollow fiber membrane required for the target sulfur dioxide removal efficiency and the number of modules required for the hollow fiber membrane.

That is, according to the present invention, when the water and the seawater reactant are brought into contact with the sulfur dioxide gas using the separation membrane, the sulfur dioxide can be removed promptly, and the use of seawater can further remove sulfur dioxide.

15, 16, 17, and 18, the removal efficiency of sulfur dioxide increases as the gas (gas) pressure increases. At this time, the liquid pressure was set to be 0.5 bar higher than the gas pressure. For this reason, when the gas pressure is increased, the gas flows from the gas-liquid interface to the liquid and bubbles are generated. Therefore, it is important to set the liquid pressure higher than the gas pressure in order to prevent bubbling, and to increase the gas pressure during the operation while increasing the liquid pressure.

Also, as can be seen from FIG. 18, the sulfur dioxide removal efficiency increases as the area of the separation membrane increases. This is because the removal of sulfur dioxide occurs at the gas-liquid interface and the larger the membrane area, the larger the contact area. Also, even when a hollow fiber membrane having the same membrane area is used, it is possible to increase the removal efficiency of dioxidation by using a membrane having a large porosity. Therefore, when a hollow fiber membrane having a high mechanical strength and a high porosity is developed, do.

It should be noted that the above-described apparatus and method are not limited to the configurations and methods of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments are selectively combined .

1: Flue gas desulfurization system for ships using hollow fiber membranes
10: Exhaust gas inlet
11: Gas pressure regulator
20: Exhaust gas outlet
30: Reactant inlet
31: Reactor pressure regulator
40:
200: Desulfurization device using membrane module
201: housing
210: Membrane module
211: hollow fiber membrane
212: Connector
220: Membrane casing
221: first mounting surface
222: first through hole
223:
224: second mounting surface
225: second through hole
230: first communication casing
231: first communication space
232: first opening hole
233: first insertion hole
234: Sealed cover
240: second communicating casing
241: second communication space
242: second opening hole
243: second insertion hole
250: flat membrane assembly
251: flat membrane
252: central tube
253: Separation hole
254: Supply Spacer
255: flat membrane spacer
256: Through-hole cover
260: Separation fluid supply pipe
270: negative pressure chamber
300: pH adjuster
310: pH measuring unit
320: Sea water mixer
330: Seawater input means
400:

Claims (15)

In the desulfurization apparatus,
housing;
An exhaust gas inlet configured to introduce exhaust gas into the housing;
A reactant inlet configured to introduce a reactant into the housing;
The exhaust gas introduced into the interior of the housing through the exhaust gas inlet portion flows into the interior or the exterior of the hollow fiber membrane module and the reactant introduced through the reactant inlet portion flows outside or inside the hollow fiber membrane module A desulfurization reaction unit to which the reactant absorbs and removes the oxidation reaction of the exhaust gas;
An exhaust gas discharging portion through which exhaust gas in a state in which sulfur dioxide is partially removed from the desulfurization reaction portion is discharged; And
And a reactant discharge portion through which the reactant is discharged from the desulfurization reaction portion in a state where the sulfur dioxide is absorbed by the desulfurization reaction portion.
The method according to claim 1,
Wherein the separator module comprises:
A separator casing connected to the reactant discharging portion through which the reactant absorbing the sulfur dioxide is discharged, the separator casing including a separator, one end closed, a through hole through which reactants can move at both ends,
A first opening formed in one end portion of the separation membrane casing and extending in the longitudinal direction of the separation membrane casing, the first separation membrane casing having a first communication space, 1 communication casing; And
A second communication hole formed in the other end of the separation membrane casing to surround the outer circumference of the separation membrane casing and having a second opening hole opened in the lengthwise direction of the separation membrane casing and having a second communication space such that the second opening hole and the through- And a first communication casing arranged to penetrate the reactant inlet portion,
Wherein the plurality of separation membrane modules have adjacent first communication casings connected to each other and adjacent second communication casings connected to each other so that the separation membrane casing is disposed parallel to each other and a gap is formed between the separation membrane casings A desulfurization apparatus using a hollow fiber membrane.
3. The method of claim 2,
Wherein the separation membrane comprises a plurality of hollow fiber membranes.
3. The method of claim 2,
Wherein the separation membrane is a flat membrane,
A flat membrane spacer having a pair of flat membranes disposed on both sides and a supply spacer for moving a fluid therein are wound around a center tube having a separation hole formed therein and the center tube is communicated only with the flat membrane spacer A desulfurization apparatus using a hollow fiber membrane.
In the desulfurization treatment method,
Exhaust gas is introduced into the housing through the exhaust gas inlet, and the reactant enters the housing through the reactor inlet;
The exhaust gas flowing through the exhaust gas inflow portion flows into or out of the hollow fiber separation membrane module of the desulfurization reaction portion and the reactant introduced through the reactive agent inflow portion flows into the hollow fiber separation membrane module or into the interior thereof, Absorbing and removing sulfur dioxide of the exhaust gas; And
And exhausting the exhaust gas from the desulfurization reaction unit through the exhaust gas exhaust unit in a state in which sulfur dioxide is partially removed and discharging the reactant through the reaction product exhaust unit in a state where sulfur dioxide is absorbed from the desulfurization reaction unit A desulfurization treatment method using a hollow fiber membrane.
In the desulfurization system,
A desulfurization apparatus using the separation membrane according to any one of claims 1 to 4; And
And a pH adjusting unit adjusting the pH of the reactant discharged from the reactant discharging unit of the desulfurizer to a value suitable for a standard value.
The method according to claim 6,
The exhaust gas is a marine exhaust gas,
Wherein the reactive agent is seawater.
8. The method of claim 7,
A gas pressure regulating unit provided at one side of the exhaust gas inflow part to regulate the pressure of the exhaust gas flowing into the desulfurization unit, and a pressure regulator provided at one side of the reactant inlet unit to regulate the pressure of the reactant flowing into the desulfurization unit The desulfurization system of claim 1, further comprising a reactant pressure regulator.
9. The method of claim 8,
Further comprising a control unit for controlling the gas pressure regulator and the reactant pressure regulator so that the pressure applied to the reactant is higher than the pressure applied to the exhaust gas, .
10. The method of claim 9,
And a pH measuring unit for measuring a pH of the reactant discharged through the reactant discharging unit in real time.
11. The method of claim 10,
The pH adjusting unit may include:
A seawater mixer into which a reactant discharged through the reactant discharging unit flows; And
And seawater introducing means for introducing the seawater into the seawater mixer,
Wherein the control unit controls the seawater input unit to adjust the pH of the reactant to be equal to or greater than the reference value when the pH value measured by the pH measuring unit is less than or equal to a set reference value.
A method for desulfurizing a ship exhaust gas,
The marine exhaust gas is introduced into the housing through the exhaust gas inflow portion and the seawater as the reactant is introduced into the housing through the reactant inlet portion;
The exhaust gas flowing through the exhaust gas inflow portion flows into or out of the hollow fiber separation membrane module of the desulfurization reaction portion and the reactant introduced through the reactive agent inflow portion flows into the hollow fiber separation membrane module or into the interior thereof, Absorbing and removing sulfur dioxide of the exhaust gas;
Exhausting the exhaust gas in a state where sulfur dioxide is partially removed from the desulfurization reaction unit through the exhaust gas discharge unit and discharging the reactant through the reaction agent discharge unit in a state where sulfur dioxide is absorbed from the desulfurization reaction unit; And
and adjusting the pH of the reactant to be discharged from the reactant discharge portion of the desulfurization apparatus to a value suitable for a reference value.
13. The method of claim 12,
A step of adjusting a pressure of an exhaust gas flowing into the desulfurization device, and a step of controlling the pressure of the reaction gas supplied to one side of the reaction gas inflow part to flow into the desulfurization device Wherein the method further comprises the step of controlling the pressure of the exhaust gas desulfurization treatment vessel.
14. The method of claim 13,
Wherein the control unit controls the gas pressure regulator and the reactant pressure regulator so that the pressure applied to the reactant is higher than the pressure applied to the exhaust gas. .
15. The method of claim 14,
wherein the pH measuring unit measures the pH of the reactant discharged through the reactant discharging unit in real time,
The step of adjusting the pH to a standard value may include:
The reactant discharged through the reactant discharging unit flows into the seawater mixer and when the pH value measured by the pH measuring unit is equal to or lower than a set reference value, the control unit controls the seawater introducing unit to introduce seawater into the seawater mixer, Wherein the pH of the desulfurizing agent is adjusted to be equal to or greater than the reference value.

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