Patent Publication Number: US-2022212138-A1

Title: Exhaust gas treatment apparatus for ships

Description:
The contents of the following Japanese patent application(s) are incorporated herein by reference: 
     NO. 2020-073150 filed in JP on Apr. 15, 2020 
     NO. PCT/JP2021/006831 filed in WO on Feb. 24, 2021 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to an exhaust gas treatment apparatus for ships. 
     2. Related Art 
     A sewage sludge treatment method and apparatus has been known in the prior art for heating sewage sludge to decrease an water content rate of the sewage sludge (see Patent Documents 1 and 2, for example). 
     Patent Document 1: Japanese Patent No. 5027697. 
     Patent Document 2: Japanese Patent Application Publication No. 2007-196931. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates one example of an exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 2  illustrates one example of a block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 3  illustrates relationship between an water content rate R of discharged material  47  and a total capacity WM of the discharged material  47 . 
         FIG. 4  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 5  illustrates one example of details of a first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2 . 
         FIG. 6  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 7  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 8  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 9  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 10  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . 
         FIG. 11  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . 
         FIG. 12  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . 
         FIG. 13  illustrates one example of an water route of a ship  200 . 
         FIG. 14  illustrates another example of the water route of the ship  200 . 
         FIG. 15  illustrates another example of the water route of the ship  200 . 
         FIG. 16  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
         FIG. 17  illustrates another example of the water route of the ship  200 . 
         FIG. 18  illustrates another example of the water route of the ship  200 . 
         FIG. 19  illustrates another example of the water route of the ship  200 . 
         FIG. 20  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In an exhaust gas treatment apparatus for ships, it is preferable to adequately control water quality of discharged water obtained by treating exhaust gas. 
     Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the claimed invention. Moreover, not all combinations of features described in the embodiments are necessary to solutions of the invention. 
       FIG. 1  illustrates one example of an exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  includes a reaction tower  10  and a heating unit  75 . The exhaust gas treatment apparatus for ships  100  may include an exhaust gas introduction tube  32  and a power unit  50 . 
     The power unit  50  is, for example, an engine, a boiler, or the like. The power unit  50  is configured to discharge exhaust gas  30 . The exhaust gas introduction tube  32  is configured to connect the power unit  50  and the reaction tower  10 . The exhaust gas  30  is introduced into the reaction tower  10 . In this example, the exhaust gas  30  discharged from the power unit  50  passes through the exhaust gas introduction tube  32 , and then is introduced into the reaction tower  10 . 
     The exhaust gas  30  contains substances such as nitrogen oxide (NO x ), sulfur oxide (SO x ), and particle matter (PM). The particle matter (PM) is also referred to as black carbon (BC). The particle matter (PM) is generated due to incomplete combustion of fossil fuel. The particle matter (PM) is a fine particle composed mainly of carbon. The particle matter (PM) is, for example, soot. 
     The reaction tower  10  may have an exhaust gas introduction port  11  for introducing the exhaust gas  30  and an exhaust gas discharge port  17  for discharging the exhaust gas  30 . Liquid  40  for treating the exhaust gas  30  is supplied to the reaction tower  10 . The liquid  40  supplied to the reaction tower  10  treats, inside the reaction tower  10 , the exhaust gas  30 . The liquid  40  is, for example, sea water or alkaline liquid. Treating the exhaust gas  30  refers to removing harmful substances contained in the exhaust gas  30 . The liquid  40  becomes exhausted liquid  46  after treating the exhaust gas  30 . The reaction tower  10  is configured to discharge the exhausted liquid  46 . 
     The reaction tower  10  in this example has a side wall  15 , a bottom surface  16 , a gas treatment unit  18 , and a liquid discharge port  19 . The reaction tower  10  in this example is cylindrical. In this example, the exhaust gas discharge port  17  is arranged at a position facing the bottom surface  16  in a direction parallel to a central axis of the cylindrical reaction tower  10 . In this example, the side wall  15  and the bottom surface  16  are respectively an internal surface and a bottom surface of the cylindrical reaction tower  10 . The exhaust gas introduction port  11  may be provided on the side wall  15 . In this example, the exhaust gas  30  passes through the exhaust gas introduction port  11  from the exhaust gas introduction tube  32 , and then is introduced into the gas treatment unit  18 . 
     The side wall  15  and the bottom surface  16  are formed of material resistant to the exhaust gas  30  as well as the liquid  40  and the exhausted liquid  46 . Said material may be a combination of an iron material such as SS400 or S-TEN (registered trademark) and at least one of a coating agent and a surface coating material, copper alloy such as naval brass, aluminum alloy such as aluminum brass, nickel alloy such as cupro-nickel, HASTELLOY (registered trademark), or stainless steel such as SUS316L, SUS329J4L, or SUS312. 
     In this specification, a technical matter may be described by using orthogonal coordinate axes of an X-axis, a Y-axis, and a Z-axis. In this specification, a plane parallel to the bottom surface  16  of the reaction tower  10  is defined as an XY-plane, and a direction from the bottom surface  16  toward the exhaust gas discharge port  17  (a direction perpendicular to the bottom surface  16 ) is defined as the Z-axis. In this specification, a predetermined direction in the XY-plane is defined as an X-axis direction, and a direction that is orthogonal to the X-axis in the XY-plane is defined as a Y-axis direction. 
     A Z-axis direction may be parallel to a vertical direction. When the Z-axis direction is parallel to the vertical direction, the XY-plane may be a horizontal plane. The Z-axis direction may also be parallel to a horizontal direction. When the Z-axis direction is parallel to the horizontal direction, the XY-plane may be parallel to the vertical direction. 
     The exhaust gas treatment apparatus for ships  100  is, for example, a cyclonic scrubber for ships. In the cyclonic scrubber, the exhaust gas  30  introduced into the reaction tower  10  travels in a direction from the exhaust gas introduction port  11  to the exhaust gas discharge port  17  (the Z-axis direction, in this example) while swirling inside the reaction tower  10 . In this example, the exhaust gas  30  swirls in the XY-plane when seen in a direction from the exhaust gas discharge port  17  to the bottom surface  16 . 
     The traveling direction of the exhaust gas  30  from the exhaust gas introduction port  11  to the exhaust gas discharge port  17  inside the reaction tower  10  is defined as a traveling direction E 1 . The fact that the exhaust gas  30  travels in the traveling direction E 1  means that the exhaust gas  30  travels in the direction from the exhaust gas introduction port  11  to the exhaust gas discharge port  17 . In this example, the traveling direction E 1  of the exhaust gas  30  is parallel to the Z-axis. In  FIG. 1 , the traveling direction E 1  of the exhaust gas  30  is indicated by a solid arrow. 
     The reaction tower  10  may have one or more trunk tubes  12  to which the liquid  40  is supplied and one or more branch tubes  13 . The reaction tower  10  may have one or more ejection units  14  for ejecting the liquid  40 . In this example, the ejection units  14  are connected to the branch tubes  13 , and the branch tubes  13  are connected to the trunk tubes  12 . 
     The reaction tower  10  in this example has three trunk tubes  12  (a trunk tube  12 - 1 , a trunk tube  12 - 2 , and a trunk tube  12 - 3 ). In this example, the trunk tube  12 - 1  and the trunk tube  12 - 3  are the trunk tubes  12  respectively provided, in a direction parallel to the Z-axis, closest to the exhaust gas introduction port  11  side and closest to the exhaust gas discharge port  17  side. In this example, the trunk tube  12 - 2  is a trunk tube  12  provided between the trunk tube  12 - 1  and the trunk tube  12 - 3  in the Z-axis direction. 
     The reaction tower  10  in this example includes branch tubes  13 - 1  to branch tubes  13 - 12 . In this example, the branch tubes  13 - 1  and the branch tubes  13 - 12  are the branch tubes  13  respectively provided, in the direction parallel to the Z-axis, closest to the exhaust gas introduction port  11  side and closest to the exhaust gas discharge port  17  side. In this example, the branch tubes  13 - 1 , the branch tubes  13 - 3 , the branch tubes  13 - 5 , the branch tubes  13 - 7 , the branch tubes  13 - 9 , and the branch tubes  13 - 11  extend in the Y-axis direction, and the branch tubes  13 - 2 , the branch tubes  13 - 4 , the branch tubes  13 - 6 , the branch tubes  13 - 8 , the branch tubes  13 - 10 , and the branch tubes  13 - 12  extend in the X-axis direction. 
     In this example, the branch tubes  13 - 1  to the branch tubes  13 - 4  are connected to the trunk tube  12 - 1 , the branch tubes  13 - 5  to the branch tubes  13 - 8  are connected to the trunk tube  12 - 2 , and the branch tubes  13 - 9  to the branch tubes  13 - 12  are connected to the trunk tube  12 - 3 . The branch tubes  13 - 1 , the branch tubes  13 - 3 , the branch tubes  13 - 5 , the branch tubes  13 - 7 , the branch tubes  13 - 9 , and the branch tubes  13 - 11  may be arranged on both sides of the trunk tube  12  in a direction parallel to the Y-axis. The branch tubes  13 - 2 , the branch tubes  13 - 4 , the branch tubes  13 - 6 , the branch tubes  13 - 8 , the branch tubes  13 - 10 , and the branch tubes  13 - 12  may be arranged on both sides of the trunk tube  12  in a direction parallel to the X-axis. 
     Taking the branch tubes  13 - 1  for example, the branch tube  13 - 1 A and the branch tube  13 - 1 B are the branch tubes  13 - 1  respectively arranged, in the direction parallel to the Y-axis, on one side and the other side of the trunk tube  12 - 1 . In the direction parallel to the Y-axis, the branch tube  13 - 1 A and the branch tube  13 - 1 B may be provided to sandwich the trunk tube  12 - 1 . Note that, in  FIG. 1 , the branch tube  13 - 1 A and the branch tube  13 - 3 A are not illustrated because they are arranged at positions overlapping with the trunk tube  12 - 1 . 
     Taking the branch tubes  13 - 2  for example, the branch tube  13 - 2 A and the branch tube  13 - 2 B are the branch tubes  13 - 2  respectively arranged, in the direction parallel to the X-axis, on one side and the other side of the trunk tube  12 - 1 . In the direction parallel to the X-axis, the branch tube  13 - 2 A and the branch tube  13 - 2 B may be provided to sandwich the trunk tube  12 - 1 . 
     The reaction tower  10  in this example includes ejection units  14 - 1  to ejection units  14 - 12 . In this example, the ejection units  14 - 1  and the ejection units  14 - 12  are the ejection units  14  respectively provided, in the direction parallel to the Z-axis, closest to the exhaust gas introduction port  11  side and closest to the exhaust gas discharge port  17  side. The ejection units  14 - 1  to the ejection units  14 - 12  in this example are respectively connected to the branch tubes  13 - 1  to the branch tubes  13 - 12 . In one branch tube  13  extending in the Y-axis direction, a plurality of ejection units  14  may be provided on one side of the trunk tube  12  in the direction parallel to the Y-axis, and a plurality of ejection units  14  may be provided on the other side thereof. In one branch tube  13  extending in the X-axis direction, a plurality of ejection units  14  may be provided on one side of the trunk tube  12  in the direction parallel to the X-axis, and a plurality of ejection units  14  may be provided on the other side thereof. Note that, in  FIG. 1 , the ejection units  14 - 1 A, the ejection units  14 - 3 A, the ejection units  14 - 5 A, the ejection units  14 - 7 A, the ejection units  14 - 9 A, and the ejection units  14 - 11 A are not illustrated because they are arranged at positions overlapping with the trunk tubes  12 . 
     The ejection units  14  have opening surfaces for ejecting the liquid  40 . In  FIG. 1 , said opening surfaces are indicated by “x” marks. In one branch tube  13 , the respective opening surfaces of the ejection units  14  arranged on one side and the other side of the trunk tube  12  may face one direction and the other direction forming a predetermined angle with an extending direction of the branch tube  13 . Taking the ejection units  14 - 2  for example, in this example, the opening surfaces of the ejection units  14 - 2 A arranged on one side of the trunk tube  12 - 1  face one direction forming a predetermined angle with the branch tube  13 - 2 A, and the opening surfaces of the ejection units  14 - 2 B arranged on the other side of the trunk tube  12 - 1  face one direction forming a predetermined angle with the branch tube  13 - 2 B. 
     The exhaust gas treatment apparatus for ships  100  may include a volumeric flow rate control unit  70 . The volumeric flow rate control unit  70  is configured to control a volumeric flow rate of the liquid  40  supplied to the reaction tower  10 . The volumeric flow rate control unit  70  may have a valve  72 . In this example, the volumeric flow rate control unit  70  is configured to control a volumeric flow rate of the liquid  40  supplied to the ejection units  14  by the valve  72 . The volumeric flow rate control unit  70  in this example includes three valves  72  (a valve  72 - 1 , a valve  72 - 2 , and a valve  72 - 3 ). The volumeric flow rate control unit  70  in this example is configured to control volumeric flow rates of the liquid  40  supplied to the trunk tube  12 - 1 , the trunk tube  12 - 2 , and the trunk tube  12 - 3 , respectively by the valve  72 - 1 , the valve  72 - 2 , and the valve  72 - 3 . The liquid  40  supplied to the trunk tubes  12  passes through the branch tubes  13 , and then is ejected from the ejection units  14  into the reaction tower  10  (to the gas treatment unit  18 ). 
     The volumeric flow rate control unit  70  may control a volumeric flow rate of the liquid  40  such that a volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 1  is greater than a volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 2 . The volumeric flow rate control unit  70  may control the volumeric flow rate of the liquid  40  such that the volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 2  is greater than a volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 3 . Ratio of the volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 3 , the volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 2 , and the volumeric flow rate of the liquid  40  supplied to the trunk tube  12 - 1  is, for example, 1:2:9. 
     The exhaust gas treatment apparatus for ships  100  may include a discharge tube  20 , a discharge tube  21 , a circulation tube  22 , an introduction tube  23 , and an introduction tube  24 . The exhaust gas treatment apparatus for ships  100  may include a switching unit  31  and a switching unit  33 . The switching unit  31  and the switching unit  33  are, for example, three-way valves. The exhaust gas treatment apparatus for ships  100  may include an introduction pump  60  and a circulation pump  61 . 
     The discharge tube  20  is connected to the reaction tower  10  and the switching unit  31 . In this example, one end of the discharge tube  20  is connected to the bottom surface  16  of the reaction tower  10 , and the other end of the discharge tube  20  is connected to the switching unit  31 . The discharge tube  21  is connected to the switching unit  31 . The circulation tube  22  is connected to the switching unit  31  and the switching unit  33 . The introduction tube  23  is connected to the switching unit  33 . The introduction tube  24  is connected to the switching unit  33  and the reaction tower  10 . In this example, one end of the introduction tube  24  is connected to the switching unit  33 , and the other end of the introduction tube  24  is connected to the reaction tower  10  via the valves  72 . 
     In this example, the exhausted liquid  46  passes through the liquid discharge port  19 , and then is discharged to the discharge tube  20 . The exhausted liquid  46  flowing through the discharge tube  20  is introduced into at least one of the discharge tube  21  and the circulation tube  22  by the switching unit  31 . The exhausted liquid  46  introduced into the discharge tube  21  is discharged out of the exhaust gas treatment apparatus for ships  100 . 
     Fluid containing the exhausted liquid  46  discharged from the reaction tower  10  and at least particle matter (PM) is defined as discharged material  47 . The discharged material  47  in this example contains said exhausted liquid  46  as well as particle matter (PM) contained in the exhaust gas  30  discharged from the power unit  50 . The discharged material  47  in this example further contains oil and contaminants. The discharged material  47  may contain said exhausted liquid  46  as well as particle matter (PM) discharged from something other than the power unit  50 . 
     The circulation pump  61  may be provided to the circulation tube  22 . In this example, the discharged material  47  flows inside the circulation tube  22  in a direction from the switching unit  31  to the switching unit  33  by the circulation pump  61 . The introduction pump  60  may be provided to the introduction tube  23 . The liquid  40  introduced into the introduction tube  23  is introduced into the switching unit  33 . 
     At least one of the liquid  40  flowing through the introduction tube  23  and the liquid  40  flowing through the circulation tube  22  is introduced into the introduction tube  24  by the switching unit  33 . The liquid  40  introduced into the introduction tube  24  is introduced into the reaction tower  10 . 
     The exhaust gas treatment apparatus for ships  100  may include a switching control unit  74 . The switching control unit  74  is configured to make a switch between supply and non-supply of the exhausted liquid  46  to the reaction tower  10 . In this example, the switching control unit  74  is configured to control, by controlling the switching unit  31 , whether the exhausted liquid  46  flowing in the discharge tube  20  should flow in the discharge tube  21  or it should flow in the circulation tube  22 . In this example, the switching control unit  74  is configured to control, by controlling the switching unit  33 , whether the liquid  40  flowing in the circulation tube  22  should flow in the introduction tube  24  or the liquid  40  flowing in the introduction tube  23  should flow in the introduction tube  24 . 
     The switching control unit  74  may control the switching unit  31  such that the exhausted liquid  46  flowing in the discharge tube  20  flows in the circulation tube  22  and control the switching unit  33  such that at least one of the liquid  40  and the exhausted liquid  46  flowing in the circulation tube  22  flows in the introduction tube  24 . When the switching control unit  74  controls the switching unit  31  and the switching unit  33  in this way, the liquid  40  and the exhausted liquid  46  circulate in the introduction tube  24 , the reaction tower  10 , the discharge tube  20 , and the circulation tube  22 . In this specification, a case is referred to as a closed mode where the liquid  40  and the exhausted liquid  46  circulate in this way. The closed mode is also referred to as a closed-loop system. 
     The switching control unit  74  may control the switching unit  31  such that the exhausted liquid  46  flowing in the discharge tube  20  flows in the discharge tube  21  and control the switching unit  33  such that the liquid  40  flowing in the introduction tube  23  flows in the introduction tube  24 . When the switching control unit  74  controls the switching unit  31  and the switching unit  33  in this way, the liquid  40  is introduced from the outside of the exhaust gas treatment apparatus for ships  100  (from the sea, for example), and the exhausted liquid  46  is discharged out of the exhaust gas treatment apparatus for ships  100  (to the sea, for example). In this specification, a case is referred to as an open mode where the liquid  40  is introduced from the outside of the exhaust gas treatment apparatus for ships  100  and the exhausted liquid  46  is discharged out of the exhaust gas treatment apparatus for ships  100 . The open mode is also referred to as an open-loop system. 
     The switching control unit  74  in this example is configured to control a switch between the above-mentioned closed mode and open mode. For the closed mode, the liquid  40  and the exhausted liquid  46  may circulate by pressure from the circulation pump  61 . For the open mode, the liquid  40  may be introduced into the reaction tower  10  by pressure from the introduction pump  60 . The exhaust gas treatment apparatus for ships  100  used through a switch between the closed mode and the open mode is also referred to as that of a hybrid system. 
     The switching control unit  74  may control the switching unit  31  and the switching unit  33  to be in an intermediate state between the above-mentioned closed mode and open mode. The intermediate state between the closed mode and the open mode refers to a state in which a part of the exhausted liquid  46  flowing in the discharge tube  20  flows in the circulation tube  22  and said part of the exhausted liquid  46  flowing in the circulation tube  22  and the liquid  40  flowing in the introduction tube  23  flow in the introduction tube  24 . In said intermediate state, another part of the exhausted liquid  46  flowing in the discharge tube  20  may flow in the discharge tube  21 . When the switching unit  31  and the switching unit  33  are three-way valves, the switching control unit  74  may control, by adjusting opening of the three-way valves, the flows of the liquid  40  and the exhausted liquid  46  to be in the intermediate state between the above-mentioned closed mode and open mode. 
     The exhaust gas treatment apparatus for ships  100  may include a cleaning agent charge unit  77 . The exhaust gas  30  contains harmful substances such as sulfur oxide (SO x ). Sulfur oxide (SO x ) is, for example, sulfurous acid gas (SO 2 ). The cleaning agent charge unit  77  is configured to charge, into at least one of the exhausted liquid  46  and the liquid  40 , a cleaning agent  78  for removing at least part of said harmful substances from the exhaust gas  30 . 
     The cleaning agent  78  may be at least any of a magnesium compound, a sodium compound, and a calcium compound. The cleaning agent  78  may be at least any of magnesium hydroxide (Mg(OH) 2 ), magnesium oxide (MgO), sodium hydroxide (NaOH), sodium hydrogen carbonate (Na 2 CO 3 ), and calcium carbonate (CaCO 3 ). 
     The cleaning agent charge unit  77  may charge the cleaning agent  78  into the exhausted liquid  46 . When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the cleaning agent charge unit  77  may charge the cleaning agent  78  into the exhausted liquid  46  flowing through the circulation tube  22 . When the switching unit  31  and the switching unit  33  are controlled in the open mode, the cleaning agent charge unit  77  may charge the cleaning agent  78  into the liquid  40  flowing through the introduction tube  24 . 
     When the cleaning agent  78  is charged into the exhausted liquid  46  and the cleaning agent  78  is sodium hydroxide (NaOH), the exhausted liquid  46  becomes a sodium hydroxide (NaOH) solution. Said exhausted liquid  46  is introduced into the introduction tube  24  by the circulation pump  61 , and then is ejected from the ejection units  14  into the reaction tower  10  (to the gas treatment unit  18 ). Reaction between said exhausted liquid  46  and the sulfurous acid gas (SO 2 ) in the gas treatment unit  18  is expressed by Chemical Formula 1 and Chemical Formula 2 described below. 
       SO 2 +H 2 O→HSO 3 .+H +   Chemical Formula 1
 
       HSO 3 .+H + +2NaOH→Na 2 SO 4 +H 2 O   Chemical Formula 2
 
     As expressed by Chemical Formula 1, sulfurous acid gas (SO 2 ) becomes bisulfite ions (HSO 3   − ) by chemical reaction. The exhausted liquid  46  becomes a solution containing bisulfite ions (HSO 3   − ) by this chemical reaction. The exhausted liquid  46  may be discharged from the inside of the reaction tower  10  to the discharge tube  20 . When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the exhausted liquid  46  is introduced into the introduction tube  24 , and then is again ejected from the ejection units  14  into the reaction tower  10 . At least part of bisulfite ions (HSO 3   − ) contained in the bisulfite ion (HSO 3   − ) solution become sodium sulfate (Na 2 SO 4 ) and water (H 2 O) by the chemical reaction expressed by Chemical Formula 2. A sodium sulfate (Na 2 SO 4 ) solution contains sulfate ions (SO 4   2− ). 
     In this specification, at least one of bisulfite ions (HSO 3   − ) and sulfate ions (SO 4   2− ) is referred to as sulfur oxide ions. When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the chemical reactions expressed by the above-mentioned Chemical Formula 1 and Chemical Formula 2 are repeated in the exhausted liquid  46 . Therefore, a concentration of sulfur oxide ions contained in the exhausted liquid  46  is easily increased in accordance with the number of times the exhausted liquid  46  circulates. When the concentration of sulfur oxide ions contained in the exhausted liquid  46  is increased, it becomes difficult for said exhausted liquid  46  to remove the harmful substances contained in the exhaust gas  30 . 
     The exhaust gas treatment apparatus for ships  100  may include a storage unit  73  and a resupply unit  76 . In this example, the storage unit  73  is connected to the circulation tube  22 . The resupply unit  76  may resupply the liquid  40  to the discharged material  47 . When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the storage unit  73  is configured to store a part of the circulating exhausted liquid  46 . Said part of the exhausted liquid  46  is, for example, drawn water referred to as so-called bleed-off water. The resupply unit  76  may resupply, to the discharged material  47 , the same amount of liquid  40  as an amount of said part of the exhausted liquid  46 . This facilitates suppression of the increase in the concentration of sulfur oxide ions contained in the exhausted liquid  46 . 
     The storage unit  73  may control, based on the concentration of sulfur oxide ions contained in the exhausted liquid  46 , an amount of the exhausted liquid  46  stored in the storage unit  73  per unit time and an amount of the liquid  40  resupplied from the resupply unit  76  to the discharged material  47  per unit time. The circulation tube  22  may be provided with a sensor for detecting the concentration of sulfur oxide ions contained in the exhausted liquid  46 . The storage unit  73  may control, based on the concentration of sulfur oxide ions detected by said sensor, the amount of the exhausted liquid  46  stored from the circulation tube  22  into the storage unit  73  per unit time and the amount of the liquid  40  resupplied from the resupply unit  76  to the discharged material  47  per unit time. 
     In this example, the discharged material  47  flows in the circulation tube  22 . The discharged material  47  contains the exhausted liquid  46  and the above-mentioned particle matter (PM). In this example, a part of the particle matter (PM) contained in the discharged material  47  flowing through the circulation tube  22  is introduced into the storage unit  73 . The storage unit  73  in this example is configured to store said part of the particle matter (PM) and a part of the exhausted liquid  46 . An water content rate of the particle matter (PM) introduced into the storage unit  73  may be  99 % or more. Said water content rate may be mass of said exhausted liquid  46  in a sum of mass of said particle matter (PM) and the mass of said exhausted liquid  46 . 
     The heating unit  75  is configured to heat the discharged material  47 . In this example, the heating unit  75  is configured to heat the discharged material  47  stored in the storage unit  73 . The heating unit  75  is configured to evaporate, by heating the discharged material  47 , at least a part of moisture contained in the discharged material  47 . The fact that the heating unit  75  is configured to evaporate at least a part of moisture contained in the discharged material  47  means that the water content rate of the particle matter (PM) stored in the storage unit  73  is reduced by 1% or more from the above-mentioned state of 99% or more through the heating by the heating unit  75 . The fact that the heating unit  75  is configured to evaporate at least a part of moisture contained in the discharged material  47  means that the evaporated moisture is discharged out of the introduction tube  24 , the reaction tower  10 , the discharge tube  20 , and the circulation tube  22  without returning to the liquid  40  and the exhausted liquid  46  circulating in the introduction tube  24 , the reaction tower  10 , the discharge tube  20 , and the circulation tube  22 . 
     The exhaust gas treatment apparatus for ships  100  may further include an economizer  130 . The economizer  130  may be provided to the exhaust gas introduction tube  32 . The economizer  130  is configured to cool the exhaust gas  30  discharged from the power unit  50 . The economizer  130  is configured to absorb heat of said exhaust gas  30 . 
     The heating unit  75  may heat the discharged material  47  by using the heat of the exhaust gas  30  absorbed by the economizer  130 . The heating unit  75  may heat the storage unit  73  by using said heat. In  FIG. 1 , a case is indicated by a dashed arrow where the heating unit  75  heats the storage unit  73  by using said heat. The heating unit  75  may be the economizer  130 . That is, the economizer  130  may heat the discharged material  47  by using the absorbed heat of the exhaust gas  30 . 
     As mentioned above, the discharged material  47  contains the particle matter (PM) and the exhausted liquid  46 . Temperature of the particle matter (PM) contained in the exhaust gas  30  is likely to be higher than temperature of the liquid  40  due to the heat of the exhaust gas  30 . The exhausted liquid  46  is removing the harmful substances contained in the exhaust gas  30 . Therefore, temperature of the exhausted liquid  46  is likely to be higher than the temperature of the liquid  40  by the chemical reaction expressed by the above-mentioned Chemical Formula 1. Therefore, the discharged material  47  is likely to have predetermined heat that is based on heat of said particle matter (PM) and heat of the exhausted liquid  46 . 
     The heating unit  75  may heat the discharged material  47  stored in the storage unit  73  by using heat of the discharged material  47  flowing through the circulation tube  22 . Since the discharged material  47  flows through the circulation tube  22 , the circulation tube  22  is configured to easily absorb the heat of the discharged material  47 . The heating unit  75  may heat, by using said heat absorbed by the circulation tube  22 , the discharged material  47  stored in the storage unit  73 . The heating unit  75  may heat the storage unit  73  by using said heat absorbed by the circulation tube  22 . In  FIG. 1 , a case is indicated by a dashed arrow where the heating unit  75  heats the storage unit  73  by using said heat absorbed by the circulation tube  22 . The heating unit  75  may be the circulation tube  22 . That is, the circulation tube  22  may heat, by using the heat absorbed from the discharged material  47 , the discharged material  47  stored in the storage unit  73 . 
     A ship mounted with the exhaust gas treatment apparatus for ships  100  may have a boiler such as one for air conditioning. The heating unit  75  may heat the discharged material  47  by using heat of said boiler. The heating unit  75  may be said boiler. 
       FIG. 2  illustrates one example of a block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention.  FIG. 2  provides details of the storage unit  73  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 1 . In  FIG. 2 , the discharge tube  20 , the discharge tube  21 , the circulation tube  22 , the introduction tube  23 , and the introduction tube  24  in  FIG. 1  are indicated by thick solid lines. In  FIG. 2 , illustrations of the introduction pump  60 , the circulation pump  61 , the switching control unit  74 , the volumeric flow rate control unit  70 , and the valves  72  illustrated in  FIG. 1  are omitted. 
     The exhaust gas treatment apparatus for ships  100  may include an water storage unit  80 , a separation unit  81 , a first storage unit  82 , and a second storage unit  83 . The storage unit  73  illustrated in  FIG. 1  may include the water storage unit  80 , the separation unit  81 , the first storage unit  82 , and the second storage unit  83 . 
     In this example, the discharged material  47  containing the exhausted liquid  46  and the particle matter (PM) is stored in the water storage unit  80 . The water storage unit  80  may be provided to the circulation tube  22 . Note that, in this example, the resupply unit  76  is connected to the water storage unit  80 . The resupply unit  76  may resupply the liquid  40  to the water storage unit  80 . 
     The particle matter (PM) contained in the exhaust gas  30  is defined as particle matter  35 . The discharged material  47  containing the exhausted liquid  46  is introduced into the separation unit  81 . The separation unit  81  is configured to separate moisture contained in said exhausted liquid  46  and the particle matter  35 . In this example, the discharged material  47  stored in the water storage unit  80  is introduced into the separation unit  81 . The water storage unit  80  may introduce, into the separation unit  81 , at least a part of the discharged material  47  introduced from the circulation tube  22  into the water storage unit  80 . The water storage unit  80  may determine, based on a concentration of the particle matter (PM) contained in the discharged material  47  flowing through the circulation tube  22 , an amount of the discharged material  47  introduced from the water storage unit  80  into the separation unit  81  per unit time. 
     Flocculating agent  79  for flocculating the particle matter  35  may or may not be introduced into the separation unit  81 . The flocculating agent  79  will be mentioned later. 
     In this example, the particle matter  35  separated by the separation unit  81  is introduced into the first storage unit  82 . In this example, a part of the exhausted liquid  46  separated by the separation unit  81  is introduced into the second storage unit  83 . 
     The first storage unit  82  is configured to store first discharged material  47 - 1 . The first discharged material  47 - 1  contains the particle matter  35  removed from the exhausted liquid  46  and a part of the exhausted liquid  46 . The second storage unit  83  is configured to store second discharged material  47 - 2 . The second discharged material  47 - 2  contains the exhausted liquid  46  from which at least a part of the particle matter  35  has been removed. 
     A content rate of the particle matter  35  contained in the first discharged material  47 - 1  is greater than a content rate of the particle matter  35  contained in the second discharged material  47 - 2 . A content rate of the exhausted liquid  46  contained in the first discharged material  47 - 1  is smaller than a content rate of the exhausted liquid  46  contained in the second discharged material  47 - 2 . The first storage unit  82  may be a sludge tank configured to store the particle matter  35  containing the exhausted liquid  46 . The second storage unit  83  may be a storage tank configured to store the exhausted liquid  46  containing the particle matter  35 . The exhausted liquid  46  stored in the second storage unit  83  may be the above-mentioned so-called bleed-off water. 
     The heating unit  75  may heat the first storage unit  82 . The heating unit  75  may heat the first discharged material  47 - 1  by heating the first storage unit  82 . The heating unit  75  may heat the second storage unit  83 . The heating unit  75  may heat the second discharged material  47 - 2  by heating the second storage unit  83 . The heating unit  75  may heat at least one of the first storage unit  82  and the second storage unit  83 . 
       FIG. 3  illustrates relationship between an water content rate R and a total capacity WM of the discharged material  47 . The water content rate R of the discharged material  47  may be a percentage of mass of the exhausted liquid  46  to total mass of the discharged material  47  (that is, a sum of the mass of the exhausted liquid  46  and mass of the particle matter  35 ). That is, said percentage may be wt. %. The total capacity WM of the discharged material  47  is volume of the discharged material  47  having said total mass. Assuming that volume of water contained in the discharged material  47  having the total capacity WM is Vw, the following formula holds: the water content rate R (%) of the discharged material  47 =the volume Vw/the total capacity WM. 
     The more the water content rate R is decreased, the more easily the total capacity WM of the discharged material  47  is decreased. The total capacity WM for when the water content rate R is 98% is defined as a capacity M. In this example, the total capacities WM are respectively ½, ⅖, ⅕, and 1/10 of the capacity M when the water content rate R is 95%, 90%, 80%, and 10%. When the water content rate R is decreased by 3% from 98%, the capacity M becomes ½, and when the water content rate R is decreased by 8%, the capacity M becomes ⅕. 
     Description will be made with reference to  FIG. 2  again. In the exhaust gas treatment apparatus for ships  100  in this example, the heating unit  75  is configured to heat the first storage unit  82 . Therefore, the exhaust gas treatment apparatus for ships  100  in this example can reduce, as illustrated in  FIG. 3 , a total capacity M of the first discharged material  47 - 1  stored in the first storage unit  82 . Therefore, the exhaust gas treatment apparatus for ships  100  in this example can downsize the first storage unit  82 . Moreover, the exhaust gas treatment apparatus for ships  100  in this example can reduce the total capacity M of the discharged material  47 - 1 , and thus a disposal cost of the first discharged material  47 - 1  (a lump of soot generated by incomplete combustion of the exhaust gas  30 , for example) is easily reduced. 
     The heating unit  75  is configured to heat the first storage unit  82 , so that the moisture contained in the exhausted liquid  46  is evaporated from the first discharged material  47 - 1 . Said evaporated moisture may be discharged out of the exhaust gas treatment apparatus for ships  100 . 
     The heating unit  75  may heat the second storage unit  83 . The second discharged material  47 - 2  (the exhausted liquid  46  from which at least a part of the particle matter  35  has been removed) is stored in the second storage unit  83 . Therefore, the heating unit  75  is configured to heat the second storage unit  83 , so that a part of the moisture contained in said exhausted liquid  46  is easily evaporated. Therefore, the exhaust gas treatment apparatus for ships  100  in this example can decrease a total capacity of the second discharged material  47 - 2 . Therefore, the exhaust gas treatment apparatus for ships  100  in this example can downsize the second storage unit (a pool configured to store the exhausted liquid  46 , for example). 
     When the moisture contained in the exhausted liquid  46  is evaporated, a total capacity of the discharged material  47  containing said exhausted liquid  46  is reduced. The total capacity of the discharged material  47  before said moisture is evaporated is defined as W 1 , and the total capacity of the discharged material  47  after said moisture is evaporated is defined as W 2 . A reduction rate RD of the total capacity of the discharged material  47  before and after the evaporation of the moisture contained in the exhausted liquid  46  is defined by (the total capacity W 1 )/(the total capacity W 2 ). 
     When moisture of a unit volume contained in the exhausted liquid  46  is evaporated, a reduction rate of a total capacity WM of the first discharged material  47 - 1  is defined as RD 1 , and a reduction rate of the total capacity of the second discharged material  47 - 2  is defined as RD 2 . As illustrated in  FIG. 3 , the higher the water content rate R is, the greater a decrease rate of the water content rate R (a slope of a curve in  FIG. 3 ) tends to be. Therefore, when the water content rate R is equal to or greater than a predetermined value (80%, for example), the reduction rate RD 1  is likely to be greater than the reduction rate RD 2 . 
     The heating unit  75  may heat the first storage unit  82  at a first temperature Te 1 . The heating unit  75  may heat the second storage unit  83  at a second temperature Te 2 . The first temperature Te 1  may be higher than the second temperature Te 2 . That is, the heating unit  75  may heat the first storage unit  82  at the first temperature Te 1  higher than the second temperature Te 2 . When the reduction rate RD 1  of the first discharged material  47 - 1  is greater than the reduction rate RD 2  of the second discharged material  47 - 2 , the first temperature Te 1  is higher than the second temperature Te 2 , so that a sum of a total capacity of the first discharged material  47 - 1  and the total capacity of the second discharged material  47 - 2  is more easily reduced by the exhaust gas treatment apparatus for ships  100  than when the first temperature Te 1  is equal to or lower than the second temperature Te 2 . As a result, a sum of a total capacity of the first storage unit  82  and a total capacity of the second storage unit  83  is more easily reduced by the exhaust gas treatment apparatus for ships  100  than when the first temperature Te 1  is equal to or lower than the second temperature Te 2 . 
     The heating unit  75  may heat the first storage unit  82  for a first period Tp 1 . The heating unit  75  may heat the second storage unit  83  for a second period Tp 2 . The first period Tp 1  may be longer than the second period Tp 2 . When the reduction rate RD 1  of the first discharged material  47 - 1  is greater than the reduction rate RD 2  of the second discharged material  47 - 2 , the first period Tp 1  is longer than the second period Tp 2 , so that the sum of the total capacity of the first discharged material  47 - 1  and the total capacity of the second discharged material  47 - 2  is more easily reduced by the exhaust gas treatment apparatus for ships  100  than when the first period Tp 1  is shorter than the second period Tp 2 . As a result, the sum of the total capacity of the first storage unit  82  and the total capacity of the second storage unit  83  is more easily reduced by the exhaust gas treatment apparatus for ships  100  than when the first period Tp 1  is shorter than the second period Tp 2 . 
     When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the heating unit  75  may continue heating of at least one of the first storage unit  82  and the second storage unit  83  while the switching unit  31  and the switching unit  33  are controlled in the closed mode. When the switching unit  31  and the switching unit  33  are changed from the closed mode to the open mode, the heating unit  75  may still continue the heating of at least one of the first storage unit  82  and the second storage unit  83  after the switching unit  31  and the switching unit  33  are changed from the closed mode to the open mode. 
     The flocculating agent  79  for flocculating the particle matter  35  may be introduced into the separation unit  81 . The particle matter  35  is flocculated, so that the total capacity WM of the first discharged material  47  is easily reduced. The flocculating agent  79  may be at least one of iron chloride (FeCl 2 ), iron sulfide (FeS), calcium sulfate (CaSO 4 ), aluminum sulfate (Al 2 (SO 4 ) 3 .16H 2 O), polyaluminum chloride (so-called PAC), polymer flocculating agent such as cationic, nonionic, and anionic polymer flocculating agents. The heating unit  75  may heat the first discharged material  47  with the particle matter  35  flocculated by the flocculating agent  79 . Note that the flocculating agent  79  does not need to be introduced into the separation unit  81 . 
     The heating unit  75  may start the heating of at least one of the first storage unit  82  and the second storage unit  83  before the switching control unit  74  makes a switch such that the exhausted liquid  46  is supplied to the reaction tower  10 . A case where the switching control unit  74  makes a switch such that the exhausted liquid  46  is supplied to the reaction tower  10  is a case where the switching control unit  74  switches the switching unit  31  and the switching unit  33  from the above-mentioned open mode to closed mode. 
     At a time point where the switching control unit  74  switches the switching unit  31  and the switching unit  33  from the open mode to the closed mode, the discharged material  47  may exist between the water storage unit  80  and the separation unit  81 , between the separation unit  81  and the first storage unit  82 , and between the separation unit  81  and the second storage unit  83 . Taking the first storage unit  82  for example, a part of said discharged material  47  existing between the water storage unit  80  and the separation unit  81  as well as said discharged material  47  existing between the separation unit  81  and the first storage unit  82  are introduced into the first storage unit  82 . 
     A total capacity of the first discharged material  47 - 1  that can be accommodated by the first storage unit  82  is defined as a capacity C 1 . At a time point where the discharged material  47  is introduced into the first storage unit  82 , when the total capacity WM of the first discharged material  47 - 1  is close to the capacity C 1  of the first storage unit  82 , the first storage unit  82  may not have a sufficient capacity (that is, C 1 -WM) to receive said discharged material  47  newly introduced into the first storage unit  82 . Therefore, the heating unit  75  is configured to start the heating of at least one of the first storage unit  82  and the second storage unit  83  before the switching control unit  74  makes the switch such that the exhausted liquid  46  is supplied to the reaction tower  10 , so that the total capacity WM of the first discharged material  47 - 1  is more easily reduced than before said heating is started, at the time point where said discharged material  47  is introduced into the first storage unit  82 . This allows the exhaust gas treatment apparatus for ships  100  to easily secure the sufficient capacity (that is, C 1 -WM) in the first storage unit  82  to receive said discharged material  47  newly introduced into the first storage unit  82 . 
       FIG. 4  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. In the exhaust gas treatment apparatus for ships  100  in this example, the heating unit  75  is further configured to heat the separation unit  81 . In this respect, the exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2 . 
     As mentioned above, the discharged material  47  is introduced into the separation unit  81 . The discharged material  47  contains the exhausted liquid  46 . In the exhaust gas treatment apparatus for ships  100  in this example, the heating unit  75  is configured to heat the separation unit  81 , and thus the moisture contained in the exhausted liquid  46  introduced into the separation unit  81  is easily evaporated. When said moisture is evaporated in the separation unit  81 , a total capacity WM of the discharged material  47  introduced into the separation unit  81  is reduced as illustrated in  FIG. 3 . Therefore, the exhaust gas treatment apparatus for ships  100  in this example is configured to easily reduce a total capacity WM of the first discharged material  47 - 1  stored in the first storage unit  82 . Moreover, when the moisture contained in the exhausted liquid  46  is evaporated in the separation unit  81 , the amount of the exhausted liquid  46  introduced from the separation unit  81  into the second storage unit  83  is easily reduced. Therefore, the exhaust gas treatment apparatus for ships  100  in this example is configured to easily reduce a total capacity of the second discharged material  47 - 2  stored in the second storage unit  83 . 
     The heating unit  75  may heat the separation unit  81  and the first storage unit  82 . The heating unit  75  is configured to heat the separation unit  81 , so that the moisture contained in the exhausted liquid  46  in the separation unit  81  is evaporated. The heating unit  75  is also configured to heat the first storage unit  82 , so that the moisture contained in the exhausted liquid  46  in the first storage unit  82  is further evaporated. Therefore, the heating unit  75  is configured to heat the separation unit  81  and the first storage unit  82 , so that the total capacity WM of the first discharged material  47 - 1  is even more easily reduced than when the heating unit  75  heats the separation unit  81  only. 
     The heating unit  75  may heat the first storage unit  82  at the first temperature Te 1 . The heating unit  75  may heat the separation unit  81  at a third temperature Te 3 . The third temperature Te 3  may be higher than the first temperature Te 1 . That is, the heating unit  75  may heat the separation unit  81  at the third temperature Te 3  higher than the first temperature Te 1 . As mentioned above, the higher the water content rate R is, the greater a decrease rate of the water content rate R of the discharged material  47  tends to be (see  FIG. 3 ). The water content rate R of the discharged material  47  in the separation unit  81  is likely to be greater than an water content rate R of the first discharged material  47 - 1  in the first storage unit  82 . Therefore, when the third temperature Te 3  is higher than the first temperature Te 1 , the decrease rate of the water content rate R in the separation unit  81  is likely to be greater than when the third temperature Te 3  is equal to or lower than the first temperature Te 1 . Therefore, the third temperature Te 3  is higher than the first temperature Te 1 , so that the total capacity WM of the first discharged material  47 - 1  is more easily reduced than when the third temperature Te 3  is equal to or lower than the first temperature Te 1 . 
     The heating unit  75  may heat the first storage unit  82  for the first period Tp 1 . The heating unit  75  may heat the separation unit  81  for a third period Tp 3 . The third period Tp 3  may be longer than the first period Tp 1 . The third period Tp 3  is longer than the first period Tp 1 , so that the total capacity WM of the first discharged material  47 - 1  is more easily reduced than when the third period Tp 3  is shorter than the first period Tp 1 . 
     The heating unit  75  may heat the separation unit  81  and the second storage unit  83 . The heating unit  75  may heat the separation unit  81  as well as the first storage unit  82  and the second storage unit  83 . 
     The heating unit  75  may start heating the separation unit  81  before the switching control unit  74  makes the switch such that the exhausted liquid  46  is supplied to the reaction tower  10 . This facilitates reduction of the total capacity WM of the discharged material  47  separated in the separation unit  81 . This allows the exhaust gas treatment apparatus for ships  100  to easily secure the sufficient capacity (that is, C 1 -WM) in the first storage unit  82  to receive said discharged material  47  newly introduced into the first storage unit  82 . 
       FIG. 5  illustrates one example of details of a first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2 . In this example, the first storage unit  82  has a plurality of storage tanks  84 . In this example, the heating unit  75  is configured to heat the plurality of storage tanks  84 . 
     In this example, the particle matter  35  separated by the separation unit  81  is introduced into a storage tank  84 - 1 . The first discharged material  47 - 1  introduced into the storage tank  84 - 1  is defined as discharged material  48 - 1 . The storage tank  84 - 1  is configured to introduce the discharged material  48 - 1  into a storage tank  84 - 2 . Similarly, a storage tank  84 -(N-1) is configured to introduce discharged material  48 -(N-1) into a storage tank  84 -N, where N is an integer of 2 or more. 
     The heating unit  75  may control, based on a content of moisture (that is, an water content rate R) contained by the discharged material  48  stored in each of the plurality of storage tanks  84 , temperature at which each of the plurality of storage tanks  84  is heated. The water content rate R of the discharged material  48  stored in each of the plurality of storage tanks  84  may be different from one another. Therefore, the heating unit  75  is configured to control, based on the water content rate R of each of the discharged material  48 - 1  to the discharged material  48 -N, the temperature at which each of the storage tank  84 - 1  to the storage tank  84 -N is heated, so that evaporation efficiency of the moisture contained in the discharged material  48  is more easily improved than when the storage tank  84 - 1  to the storage tank  84 -N are heated at the same temperature. 
     When the first storage unit  82  has the plurality of storage tanks  84 , the heating unit  75  may set, for a storage tank  84  that stores the discharged material  48  having a higher water content rate R, temperature at which the storage tank  84  is heated, to be higher. In this example, since the heating unit  75  heats the plurality of storage tanks  84 , the water content rate R of the discharged material  48 -N is likely to be lower than the water content rate R of the discharged material  48 -(N-1). A decrease rate of the water content rate R is represented by a slope of a tangent of the curve (see  FIG. 3 ) at any water content rate R. As illustrated in  FIG. 3 , the higher the water content rate R is, the greater the decrease rate of the water content rate R tends to be. Therefore, the heating unit  75  may set temperature at which the storage tank  84 -(N-1) is heated, to be higher than temperature at which the storage tank  84 -N is heated. As a result, the total capacity WM of the first discharged material  47  stored in the first storage unit  82  (that is, a sum of a total capacity of the discharged material  48 - 1  to a total capacity of the discharged material  48 -N) is more easily reduced than when the heating unit  75  heats the storage tank  84 - 1  to the storage tank  84 -N at the same temperature. 
       FIG. 6  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. In the exhaust gas treatment apparatus for ships  100  in this example, the separation unit  81  has a clarification unit  85  and a dehydration unit  86 . In this respect, the exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2 . 
     In this example, the discharged material  47  stored in the water storage unit  80  is introduced into the clarification unit  85 . The clarification unit  85  in this example is configured to derive the exhausted liquid  46  and particle matter  35 - 1  by clarifying the discharged material  47 . Said exhausted liquid  46  may be introduced into the second storage unit  83 . In this example, the clarification unit  85  is configured to introduce the particle matter  35 - 1  into the dehydration unit  86 . The dehydration unit  86  in this example is configured to derive particle matter  35 - 2  by dehydrating the particle matter  35 - 1 . The particle matter  35 - 2  may be introduced into the first storage unit  82 . Note that, in this example, the flocculating agent  79  may or may not be introduced into the clarification unit  85 . 
     The dehydration unit  86  may be a dehydrator configured to dehydrate moisture by centrifugal force of rotation. The particle matter  35 - 1  contains the exhausted liquid  46 . The dehydration unit  86  may dehydrate a part of the moisture contained in said exhausted liquid  46  by rotating the particle matter  35 - 1 . The dehydration unit  86  is an warmer configured to evaporate moisture by warming, and may be an warmer different from the heating unit  75 . The moisture dehydrated by the dehydration unit  86  may be discharged out of the exhaust gas treatment apparatus for ships  100 . 
     In the exhaust gas treatment apparatus for ships  100  in this example, since the separation unit  81  has the dehydration unit  86 , the water content rate R of the first discharged material  47 - 1  introduced into the first storage unit  82  is more easily reduced than when the separation unit  81  does not have the dehydration unit  86 . Therefore, in the exhaust gas treatment apparatus for ships  100  in this example, the total capacity WM of the first discharged material  47 - 1  is likely to be smaller than when the separation unit  81  does not have the dehydration unit  86 . Note that the heating unit  75  may heat said first discharged material  47 - 1 . 
       FIG. 7  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2  in that the former further includes a condensation unit  90 . 
     As mentioned above, the heating unit  75  is configured to heat at least one of the first storage unit  82  and the second storage unit  83 . When the heating unit  75  heats the first storage unit  82 , at least a part of the exhausted liquid  46  contained in the first discharged material  47 - 1  stored in the first storage unit  82  is evaporated through the heating by the heating unit  75 . Vapor generated by said heating is defined as first vapor  41 . When the heating unit  75  heats the second storage unit  83 , at least a part of the exhausted liquid  46  contained in the second discharged material  47 - 2  stored in the second storage unit  83  is evaporated through the heating by the heating unit  75 . Vapor generated by said heating is defined as second vapor  42 . 
     The condensation unit  90  may condense at least one of the first vapor  41  and the second vapor  42 . The condensation unit  90  may generate liquid  43  by condensing the first vapor  41 . The condensation unit  90  may generate the liquid  43  by condensing the second vapor  42 . The condensation unit  90  may introduce the liquid  43  into the water storage unit  80 . The liquid  43  may be mixed with the exhausted liquid  46  in the water storage unit  80 . When the switching unit  31  and the switching unit  33  are controlled in the closed mode, the liquid  43  mixed with the exhausted liquid  46  may circulate in the circulation tube  22 , the introduction tube  24 , the reaction tower  10 , and the discharge tube  20 . 
     Since the first vapor  41  and the second vapor  42  are generated through the heating by the heating unit  75 , the first vapor  41  and the second vapor  42  are less likely to contain sulfur oxide ions. Therefore, the liquid  43  is mixed with the exhausted liquid  46 , so that the concentration of sulfur oxide ions contained in the exhausted liquid  46  is easily reduced. Therefore, the exhaust gas treatment apparatus for ships  100  in this example is configured to easily suppress the increase in the concentration of sulfur oxide ions contained in the exhausted liquid  46  even when the switching unit  31  and the switching unit  33  are controlled in the closed mode. 
       FIG. 8  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 7  in that the liquid  43  generated by the condensation unit  90  is introduced into the circulation tube  22 . 
     The liquid  43  may be introduced into the circulation tube  22 . The liquid  43  may be mixed with the exhausted liquid  46  in the circulation tube  22 . The liquid  43  may be introduced into the circulation tube  22 , outside the storage unit  73  (a dashed-dotted line in  FIG. 7 ). The liquid  43  may be introduced into the circulation tube  22  connecting the switching unit  31  and the water storage unit  80 . 
       FIG. 9  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 2  in that the former further includes a first heat exchanger  98  and a second heat exchanger  99  as well as a switching unit  34  and a switching unit  36 . 
     The first heat exchanger  98  is configured to exchange the heat of the exhausted liquid  46  and heat of the power unit  50 . The first heat exchanger  98  may cool the power unit  50  by exchanging the heat of the exhausted liquid  46  and the heat of the power unit  50 . The exhaust gas treatment apparatus for ships  100  may include the first heat exchanger  98 , thereby utilizing the exhausted liquid  46  as cooling water for the power unit  50 . 
     Since the power unit  50  burns fossil fuel, temperature of the power unit  50  is likely to be higher than the temperature of the exhausted liquid  46 . Therefore, the first heat exchanger  98  is configured to exchange the heat of the exhausted liquid  46  and the heat of the power unit  50 , so that the power unit  50  is easily cooled. 
     The exhausted liquid  46  contained in the second discharged material  47 - 2  stored in the second storage unit  83  may be introduced into the first heat exchanger  98 . As mentioned above, the first storage unit  82  is configured to store the first discharged material  47 - 1 , and the second storage unit  83  is configured to store the second discharged material  47 - 2 . Since the content rate of the particle matter  35  contained in the second discharged material  47 - 2  is smaller than the content rate of the particle matter  35  contained in the first discharged material  47 - 1 , viscosity of the second discharged material  47 - 2  is likely to be smaller than viscosity of the first discharged material  47 - 1 . Therefore, the second discharged material  47 - 2  is configured to more easily flow through a predetermined closed space than the first discharged material  47 - 1 . The exhausted liquid  46  contained in the second discharged material  47 - 2  may be constantly introduced into the first heat exchanger  98 . 
     The second heat exchanger  99  is configured to exchange the heat of the exhausted liquid  46  and heat of the first discharged material  47 - 1 . The second heat exchanger  99  may exchange the heat of the exhausted liquid  46  and heat of the first storage unit  82 . The second heat exchanger  99  may cool the first discharged material  47 - 1  by exchanging the heat of the exhausted liquid  46  and the heat of the first discharged material  47 - 1 . The exhaust gas treatment apparatus for ships  100  may include the second heat exchanger  99 , thereby utilizing the exhausted liquid  46  as cooling water for the first discharged material  47 - 1 . 
     When the heating unit  75  heats the first storage unit  82 , temperature of the particle matter  35  contained in the first discharged material  47 - 1  is likely to be higher than temperature of the particle matter  35  contained in the discharged material  47  before the separation by the separation unit  81 . Therefore, the second heat exchanger  99  is configured to exchange the heat of the exhausted liquid  46  and the heat of the first discharged material  47 - 1 , so that the first discharged material  47 - 1  is easily cooled. 
     The switching unit  34  and the switching unit  36  may be provided to the circulation tube  22 . The switching unit  34  and the switching unit  36  are, for example, three-way valves. 
     The switching control unit  74  may control the switching unit  34  such that at least a part of the exhausted liquid  46  flowing in the circulation tube  22  is introduced into the second heat exchanger  99  and control the switching unit  36  such that the exhausted liquid  46  introduced into the second heat exchanger  99  flows in the circulation tube  22 . When the switching unit  34  is a three-way valve, the switching control unit  74  may control, by adjusting the opening of said three-way valve, the switching unit  34  such that a part of the exhausted liquid  46  (exhausted liquid  46 - 1 ) flows in the circulation tube  22  and another part of the exhausted liquid  46  (exhausted liquid  46 - 2 ) is introduced into the second heat exchanger  99 . When the switching unit  36  is a three-way valve, the switching control unit  74  may control, by adjusting the opening of said three-way valve, the switching unit  36  such that the exhausted liquid  46 - 1  and the exhausted liquid  46 - 2  are introduced into the switching unit  33 . The exhausted liquid  46  flowing in the circulation tube  22  may be constantly introduced into the second heat exchanger  99 . 
     The exhaust gas treatment apparatus for ships  100  may include at least one of the first heat exchanger  98  and the second heat exchanger  99 . The exhaust gas treatment apparatus for ships  100  in this example includes both the first heat exchanger  98  and the second heat exchanger  99 . When the exhaust gas treatment apparatus for ships  100  does not include the second heat exchanger  99 , the exhaust gas treatment apparatus for ships  100  does not need to include the switching unit  34  and the switching unit  36 . 
     The exhaust gas treatment apparatus for ships  100  may include a fuel supply unit  97 . The fuel supply unit  97  is configured to supply the power unit  50  with fuel for operating the power unit  50 . Said fuel is, for example, fuel oil C. When said fuel is fuel oil C, viscosity of the fuel oil C supplied to the power unit  50  is desirably lower than viscosity of the fuel oil C at room temperature. 
     Heat of the economizer  130  may be supplied to the fuel supply unit  97 . The heat of the economizer  130  is supplied to the fuel supply unit  97 , so that the fuel supplied from the fuel supply unit  97  to the power unit  50  may be heated. In the exhaust gas treatment apparatus for ships  100  in this example, since the heat of the economizer  130  is supplied to the fuel supply unit  97 , when the fuel supplied from the fuel supply unit  97  to the power unit  50  is fuel oil C, the viscosity of the fuel oil C is easily decreased through heating of the fuel oil C by said heat. 
       FIG. 10  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . The exhaust gas treatment apparatus for ships  100  in this example includes a gas supply unit  96  in place of the second heat exchanger  99  in the example illustrated in  FIG. 9 . At least one of the first storage unit  82  and the second storage unit  83  may have the gas supply unit  96 . In this example, the first storage unit  82  has the gas supply unit  96 . 
     The gas supply unit  96  in this example is configured to supply gas  37  into the first discharged material  47 - 1 . The gas  37  may be the atmosphere. The gas supply unit  96  may supply aeration by the gas  37  into the first discharged material  47 - 1 . The gas supply unit  96  is configured to supply the gas  37  into the first discharged material  47 - 1 , so that the heat of the first discharged material  47 - 1  and heat of the gas  37  are easily exchanged. The heat of the first discharged material  47 - 1  and the heat of the gas  37  are exchanged, so that the first discharged material  47 - 1  is easily cooled. 
     When the second storage unit  83  has the gas supply unit  96 , said gas supply unit  96  is configured to supply the gas  37  into the second discharged material  47 - 2 . Said gas supply unit  96  may supply the aeration by the gas  37  into the second discharged material  47 - 2 . The gas supply unit  96  is configured to supply the gas  37  into the second discharged material  47 - 2 , so that heat of the second discharged material  47 - 2  and the heat of the gas  37  are easily exchanged. The heat of the second discharged material  47 - 2  and the heat of the gas  37  are exchanged, so that the second discharged material  47 - 2  is easily cooled. 
       FIG. 11  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . The exhaust gas treatment apparatus for ships  100  in this example further includes an air sending unit  95 . The air sending unit  95  may be provided to the first storage unit  82 . At least one of the first storage unit  82  and the second storage unit  83  may have the air sending unit  95 . In this example, the first storage unit  82  has the air sending unit  95 . 
     The air sending unit  95  in this example is configured to send air to the first discharged material  47 - 1 . The air sending unit  95  is, for example, an air sending fan or an air sending blower. The air sending unit  95  may send air into the first storage unit  82  and to the outside of the first discharged material  47 - 1 . The air sending unit  95  is configured to send air to the first discharged material  47 - 1 , so that the exhausted liquid  46  contained in the first discharged material  47 - 1  is easily evaporated. The air sending unit  95  may generate vapor  38  by evaporating said exhausted liquid  46 . 
     When the second storage unit  83  has the air sending unit  95 , said air sending unit  95  is configured to send air to the second discharged material  47 - 2 . The air sending unit  95  may send air into the second storage unit  83  and to the outside of the second discharged material  47 - 2 . The air sending unit  95  is configured to send air to the second discharged material  47 - 2 , so that the exhausted liquid  46  contained in the second discharged material  47 - 2  is easily evaporated. The air sending unit  95  may generate the vapor  38  by evaporating said exhausted liquid  46 . 
       FIG. 12  illustrates another example of the first storage unit  82  in the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 9 . The exhaust gas treatment apparatus for ships  100  in this example includes a pressure control unit  94  in place of the second heat exchanger  99  in the example illustrated in  FIG. 9 . At least one of the first storage unit  82  and the second storage unit  83  may have the pressure control unit  94 . In this example, the first storage unit  82  has the pressure control unit  94 . 
     The pressure control unit  94  in this example is configured to control pressure inside the first storage unit  82 . Gas inside the first storage unit  82  and outside the first discharged material  47 - 1  is defined as gas  89 . The gas  89  may include the vapor  38 . The pressure control unit  94  may control the pressure inside the first storage unit  82  through suction or introduction of the gas  89 . The pressure control unit  94  may reduce the pressure inside the first storage unit  82 . When the pressure control unit  94  reduces the pressure inside the first storage unit  82 , the exhausted liquid  46  contained in the first discharged material  47 - 1  is easily evaporated. This facilitates reduction of the water content rate R of the first discharged material  47 - 1  (see  FIG. 3 ). 
     When the second storage unit  83  has the pressure control unit  94 , said pressure control unit  94  is configured to control pressure inside the second storage unit  83 . The pressure control unit  94  may control the pressure inside the second storage unit  83  through suction or introduction of the gas  89  inside the second storage unit  83  and outside the second discharged material  47 - 2 . The pressure control unit  94  may reduce the pressure inside the second storage unit  83 . When the pressure control unit  94  reduces the pressure inside the second storage unit  83 , the exhausted liquid  46  contained in the second discharged material  47 - 3  is easily evaporated. This facilitates reduction of an water content rate R of the second discharged material  47 - 2 . 
     The pressure control unit  94  may control the pressure inside the first storage unit  82  based on the water content rate R of the first discharged material  47 - 1 . When the water content rate R of the first discharged material  47 - 1  is equal to or smaller than a predetermined value, the pressure control unit  94  may increase the water content rate R of the first discharged material  47 - 1  by increasing the pressure inside the first storage unit  82 . Note that the water content rate R of the first discharged material  47 - 1  may be increased through introduction of the liquid  40  into the first storage unit  82 . Said liquid  40  may be liquid  40  other than the liquid  40  circulating in the introduction tube  24 , the reaction tower  10 , the discharge tube  20 , and the circulation tube  22 . 
       FIG. 13  illustrates one example of an water route of a ship  200 . In  FIG. 13 , a port A and a port B are respectively ports which the ship  200  leaves and arrives in. Distance between the port A and the port B is defined as distance dl. In this example, the reaction tower  10  is mounted on the ship  200 . 
     The heating unit  75  (see  FIG. 1 ) may control the heating of at least one of the first storage unit  82  (see  FIG. 2 ) and the second storage unit  83  (see  FIG. 2 ) based on a navigation schedule of the ship  200 . The heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on the navigation schedule of the ship  200 , which allows the exhaust gas treatment apparatus for ships  100  to easily control the total capacity WM of the first discharged material  47 - 1  stored in the first storage unit  82  and the total capacity of the second discharged material  47 - 2  stored in the second storage unit  83 . 
     The heating unit  75  may approximate, based on the distance d 1 , a total amount of the first discharged material  47 - 1  discharged from the reaction tower  10 . The heating unit  75  may approximate a total amount of the first discharged material  47 - 1  discharged as the ship  200  sails for the distance d 1 . The heating unit  75  may control, based on said approximated total amount of the first discharged material  47 - 1 , at least one of the first temperature Te 1  and the first period Tp 1  at and for which the first storage unit  82  is heated. When the heating unit  75  controls the first period Tp 1 , the heating unit  75  may further control timing at which the first period Tp 1  is started. 
     The heating unit  75  may approximate, based on the distance d 1 , a total amount of the second discharged material  47 - 2  discharged from the reaction tower  10 . The heating unit  75  may approximate a total amount of the second discharged material  47 - 2  discharged as the ship  200  sails for the distance d 1 . The heating unit  75  may control, based on said approximated total amount of the second discharged material  47 - 2 , at least one of the second temperature Te 2  and the second period Tp 2  at and for which the second storage unit  83  is heated. When the heating unit  75  controls the second period Tp 2 , the heating unit  75  may further control timing at which the second period Tp 2  is started. 
       FIG. 14  illustrates another example of the water route of the ship  200 . In this example, the ship  200  leaves the port A and then is anchored in the port B, and leaves the port B and then arrives in a port C. It is assumed that the ship  200  is currently sailing at a position PS between the port A and the port B. 
     The heating unit  75  (see  FIG. 1 ) may heat the first storage unit  82  (see  FIG. 2 ) in at least one of before the ship  200  arrives in port and while the ship  200  is anchored in port. Before the ship  200  arrives in port refers to before the ship  200  sailing in the sea arrives in a port where the ship  200  is scheduled to be next anchored. In this example, the heating unit  75  is configured to heat the first storage unit  82  in at least one of before the ship  200  arrives in the port B and while the ship  200  is anchored in the port B. 
     As mentioned above, the first discharged material  47 - 1  is stored in the first storage unit  82 . The first storage unit  82  is, for example, a sludge tank. When the heating unit  75  heats the first storage unit  82 , the water content rate R of the first discharged material  47 - 1  ( FIG. 3 ) is easily decreased. When the water content rate R of the first discharged material  47 - 1  is decreased, the total capacity WM of the first discharged material  47 - 1  is easily decreased. The first discharged material  47 - 1  with the total capacity WM decreased is likely to become a lump of particle matter  35 . Said lump of particle matter  35  may be possibly unloaded from the ship  200  in a port (the port B and the port C, in this example) where the ship  200  is anchored. In this example, since the heating unit  75  heats the first storage unit  82  before the ship  200  arrives in the port B, the lump of particle matter  35  can be unloaded from the ship  200  shortly after the ship  200  arrives in the port B. 
     The heating unit  75  may heat the first storage unit  82  while the ship  200  is anchored in the port B. The heating unit  75  is configured to heat the first storage unit  82  while the ship  200  is anchored in the port B, so that, after the lump of particle matter  35  has reached the total capacity WM that can be unloaded from the ship  200 , said particle matter  35  can be unloaded from the ship  200 . 
       FIG. 15  illustrates another example of the water route of the ship  200 . In this example, the ship  200  leaves the port A and then is anchored in the port B, and leaves the port B and then arrives in the port C. It is assumed that the ship  200  is currently anchored in the port B. 
     The heating unit  75  (see  FIG. 1 ) may heat the second storage unit  83  (see FIG.  2 ) before the ship  200  leaves port. In this example, the heating unit  75  is configured to heat the second storage unit  83  before the ship  200  leaves the port B. 
     As mentioned above, the second discharged material  47 - 2  is stored in the second storage unit  83 . The second storage unit  83  is, for example, a storage tank. Since the second storage unit  83  has a heat capacity, it may take a predetermined time before the second discharged material  47 - 2  starts to be heated after the heating unit  75  starts heating the second storage unit  83 . In this example, since the heating unit  75  heats the second storage unit  83  before the ship  200  leaves the port B, the second discharged material  47 - 2  is easily heated shortly after the second discharged material  47 - 2  is introduced into the second storage unit  83  after the ship  200  leaves the port B. 
       FIG. 16  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 4  in that the former further includes a positional information obtainment unit  93 . In this example, positional information obtained by the positional information obtainment unit  93  is sent to the heating unit  75 . 
       FIG. 17  illustrates another example of the water route of the ship  200 . In this example, the ship  200  leaves the port A and then is anchored in the port B, and leaves the port B and then arrives in the port C. It is assumed that the ship  200  is currently navigating at the position PS between the port A and the port B. 
     The positional information obtainment unit  93  is configured to obtain the current position PS of the ship  200 . The positional information obtainment unit  93  is, for example, GPS (Global Positioning System). Distance between the port A and the position PS is defined as distance dd 1 . Distance between the position PS and the port B is defined as distance dd 2 . Note that a sum of the distance dd 1  and the distance dd 2  is the distance d 1 . 
     The heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on the current position PS of the ship  200  obtained by the positional information obtainment unit  93 . The heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on said current position PS, which allows the exhaust gas treatment apparatus for ships  100  to easily control, while the ship  200  is navigating, the total capacity WM of the first discharged material  47 - 1  stored in the first storage unit  82  and the total capacity of the second discharged material  47 - 2  stored in the second storage unit  83 . 
     The heating unit  75  may approximate, based on distance between the current position PS of the ship  200  and a port where the ship  200  is anchored (a sum of the distance dd 2  and distance d 2 , in this example), the total amount of the first discharged material  47 - 1  discharged from the reaction tower  10 . The heating unit  75  may approximate a total amount of the first discharged material  47 - 1  discharged as the ship  200  sails for scheduled navigation distance from the current position PS. The heating unit  75  may control, based on said approximated total amount of the first discharged material  47 - 1 , at least one of the first temperature Te 1  and the first period Tp 1  at and for which the first storage unit  82  is heated. When the heating unit  75  controls the first period Tp 1 , the heating unit  75  may further control timing at which the first period Tp 1  is started. 
     The heating unit  75  may approximate, based on the distance between the current position PS of the ship  200  and the port where the ship  200  is anchored (the sum of the distance dd 2  and distance d 2 , in this example), the total amount of the second discharged material  47 - 2  discharged from the reaction tower  10 . The heating unit  75  may approximate a total amount of the second discharged material  47 - 2  discharged as the ship  200  sails for scheduled navigation distance from the current position PS. The heating unit  75  may control, based on said approximated total amount of the second discharged material  47 - 2 , at least one of the second temperature Te 2  and the second period Tp 2  at and for which the second storage unit  83  is heated. When the heating unit  75  controls the second period Tp 2 , the heating unit  75  may further control the timing at which the second period Tp 2  is started. 
     The heating unit  75  may control heating of at least one of the first storage unit  82 , the second storage unit  83 , and the separation unit  81  based on the current position PS of the ship  200  obtained by the positional information obtainment unit  93 . The heating unit  75  may control, based on the approximated total amount of the first discharged material  47 - 1  mentioned above, at least one of the third temperature Te 3  and the third period Tp 3  at and for which the separation unit  81  is heated. When the heating unit  75  controls the third period Tp 3 , the heating unit  75  may further control timing at which the third period Tp 3  is started. 
       FIG. 18  illustrates another example of the water route of the ship  200 . In this example, the ship  200  navigates a first sea area A 1 , and then navigates a second sea area A 2 . In  FIG. 18 , the water route of the ship  200  is indicated by an arrow. A regulation value of a concentration of the particle matter  35  contained in the exhaust gas  30  in the first sea area A 1  is defined as a first concentration D 1 , and a regulation value thereof in the second sea area A 2  is defined as a second concentration D 2 . The second concentration D 2  is lower than the first concentration D 1 . That is, it is assumed that regulation of the concentration of the particle matter  35  in the second sea area A 2  is stricter than said regulation in the first sea area A 1 . 
     In  FIG. 18 , a boundary between the first sea area A 1  and the second sea area A 2  is indicated by a dashed line. A position of an intersection where the water route of the ship  200  meets the boundary between the first sea area A 1  and the second sea area A 2  is defined as a position C. It is assumed that the ship  200  is currently navigating the position PS in the first sea area A 1 . 
     The heating unit  75  (see  FIG. 1 ) may control the heating of at least one of the first storage unit  82  (see  FIG. 2 ) and the second storage unit  83  (see  FIG. 2 ) before the ship  200  navigates the second sea area A2. As mentioned above, the second concentration D2 which is the regulation value in the second sea area A 2  is lower than the first concentration D1 which is the regulation value in the first sea area A 1 . Therefore, an amount of the first discharged material  47 - 1  stored in the first storage unit  82  per unit time while the ship  200  is navigating the second sea area A 2  is likely to be greater than an amount of the first discharged material  47 - 1  stored in the first storage unit  82  per unit time while the ship  200  is navigating the first sea area A 1 . 
     In this example, the heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  before the ship  200  navigates the second sea area A 2 . Therefore, before the ship  200  navigates the second sea area A 2 , at least one of the total capacity WM of the first discharged material  47 - 1  stored in the first storage unit  82  and the total capacity of the second discharged material  47 - 2  stored in the second storage unit  83  is easily reduced. Therefore, before the ship  200  navigates the second sea area A 2 , a remaining capacity of the first storage unit  82  and a remaining capacity of the second storage unit  83  are easily increased. 
     When the ship  200  is navigating the first sea area A 1 , the positional information obtainment unit  93  (see  FIG. 16 ) may obtain the current position PS of the ship  200 . Distance between the current position PS and the position C is defined as distance d 3 . The distance d 3  is distance from the current position PS to the second sea area A 2 . 
     When the ship  200  is navigating the first sea area A 1 , the heating unit  75  may approximate the total amount of the first discharged material  47 - 1  and the total amount of the second discharged material  47 - 2  for when the ship  200  navigates for the distance d 3 . The heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on said approximated total amounts of the first discharged material  47 - 1  and the second discharged material  47 - 2 . The heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on the distance d 3 , so that necessary and sufficient remaining capacities of the first storage unit  82  and the second storage unit  83  are easily secured at a time point where the ship  200  enters the second sea area A 2  from the first sea area A 1 . 
     The second sea area A 2  may be a so-called Emission Control Area (ECA) sea area. The ECA sea area is a sea area where a concentration of at least one of nitrogen oxide (NOx), sulfur oxide (SOx), and particle matter (PM) contained in the exhaust gas  30  is more strictly regulated than in a normal sea area. 
       FIG. 19  illustrates another example of the water route of the ship  200 . In this example, the ship  200  navigates the second sea area A 2 , and then navigates the first sea area A 1 . In  FIG. 19 , the water route of the ship  200  is indicated by an arrow. The heating unit  75  (see  FIG. 1 ) may control the heating of at least one of the first storage unit  82  (see  FIG. 2 ) and the second storage unit  83  (see  FIG. 2 ) before the ship  200  navigates the first sea area A 1 . 
     As mentioned above, the amount of the first discharged material  47 - 1  stored in the first storage unit  82  per unit time while the ship  200  is navigating the second sea area A 2  is likely to be greater than the amount of the first discharged material  47 - 1  stored in the first storage unit  82  per unit time while the ship  200  is navigating the first sea area A 1 . Therefore, the heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  before the ship  200  navigates the first sea area A 1 , so that, before the ship  200  navigates the first sea area A 1 , at least one of the total capacity WM of the first discharged material  47 - 1  stored in the first storage unit  82  and the total capacity of the second discharged material  47 - 2  stored in the second storage unit  83  is easily reduced. Therefore, before the ship  200  navigates the first sea area A 1 , the remaining capacity of the first storage unit  82  and the remaining capacity of the second storage unit  83  are easily increased. 
     When the ship  200  is navigating the second sea area A 2 , the positional information obtainment unit  93  (see  FIG. 16 ) may obtain the current position PS of the ship  200 . Distance between the current position PS and the position C is defined as distance d 4 . The distance d 4  is distance from the current position PS to the first sea area A 1 . 
     The heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on the distance d 4 . When the ship  200  is navigating the second sea area A 2 , the heating unit  75  may approximate the total amount of the first discharged material  47 - 1  and the total amount of the second discharged material  47 - 2  for when the ship  200  navigates for the distance d 4 . The heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on said approximated total amounts of the first discharged material  47 - 1  and the second discharged material  47 - 2 . The heating unit  75  is configured to control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on the distance d 3 , so that necessary and sufficient remaining capacities of the first storage unit  82  and the second storage unit  83  are easily secured at a time point where the ship  200  enters the first sea area A 1  from the second sea area A 2 . 
       FIG. 20  illustrates another example of the block diagram of the exhaust gas treatment apparatus for ships  100  according to one embodiment of the present invention. The exhaust gas treatment apparatus for ships  100  in this example is different from the exhaust gas treatment apparatus for ships  100  illustrated in  FIG. 16  in that the former further includes an output control unit  91  and a remaining capacity obtainment unit  92 . 
     The output control unit  91  is configured to control output of the power unit  50 . When the power unit  50  is an engine, the output of the power unit  50  may be rotational speed of the engine or may be a temporal rate of change in the rotational speed of the engine. 
     The remaining capacity obtainment unit  92  is configured to obtain at least one of the remaining capacity of the first storage unit  82  and the remaining capacity of the second storage unit  83 . The remaining capacity of the first storage unit  82  and the remaining capacity of the second storage unit  83  are respectively defined as a remaining capacity RM 1  and a remaining capacity RM 2 . A capacity of the second discharged material  47 - 2  that can be accommodated by the second storage unit  83  is defined as a capacity C 2 . As mentioned above, the capacity of the first discharged material  47 - 1  that can be accommodated by the first storage unit  82  is the capacity C 1 . The total capacity of the second discharged material  47 - 2  accommodated in the second storage unit  83  is defined as the total capacity W 2 . Note that the total capacity of the first discharged material  47 - 1  accommodated in the first storage unit  82  is the total capacity WM (see  FIG. 3 ). 
     The remaining capacity RM 1  of the first storage unit  82  refers to difference between the capacity C 1  and the total capacity WM. When the first storage unit  82  is a sludge tank, the remaining capacity RM 1  may be a spatial capacity inside said sludge tank and above the first discharged material  47 - 1 . The remaining capacity RM 2  of the second storage unit  83  refers to difference between the capacity C 2  and the total capacity W 2 . When the second storage unit  83  is a storage tank, the remaining capacity RM 2  may be a spatial capacity inside said storage tank and above the second discharged material  47 - 2 . 
     The output control unit  91  may control the output of the power unit  50  based on at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . As mentioned above, the power unit  50  is configured to discharge the exhaust gas  30  ( FIG. 1 ). Said exhaust gas  30  is likely to contain the particle matter  35  (see  FIG. 2 ). When the power unit  50  is an engine, the greater the output of the power unit  50  (the rotational speed of the engine, for example) is, the more easily an amount of the particle matter  35  discharged per unit time is increased. 
     The remaining capacity obtainment unit  92  may obtain whether the remaining capacity RM 1  of the first storage unit  82  is equal to or greater than a predetermined threshold value th 1  or less than the threshold value th 1 . When the remaining capacity RM 1  obtained by the remaining capacity obtainment unit  92  is equal to or greater than the threshold value th 1 , the output control unit  91  may reduce the output of the power unit  50 . This allows the exhaust gas treatment apparatus for ships  100  to easily prevent the total capacity WM from reaching the capacity C 1  of the first storage unit  82  (prevent the remaining capacity RM 1  from becoming zero) before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example). When the remaining capacity RM 1  obtained by the remaining capacity obtainment unit  92  is less than the threshold value th 1 , the output control unit  91  may increase the output of the power unit  50 . 
     The remaining capacity obtainment unit  92  may obtain whether the remaining capacity RM 2  of the second storage unit  83  is equal to or greater than a predetermined threshold value th 2  or less than the threshold value th 2 . When the remaining capacity RM 2  obtained by the remaining capacity obtainment unit  92  is equal to or greater than the threshold value th 2 , the output control unit  91  may reduce the output of the power unit  50 . This allows the exhaust gas treatment apparatus for ships  100  to easily prevent the total capacity of the second discharged material  47 - 2  from reaching the capacity C 2  of the second storage unit  83  (prevent the remaining capacity RM 2  from becoming zero) before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example). When the remaining capacity RM 2  obtained by the remaining capacity obtainment unit  92  is less than the threshold value th 2 , the output control unit  91  may increase the output of the power unit  50 . 
     As mentioned above, the positional information obtainment unit  93  is configured to obtain the current position PS of the ship  200  (see  FIG. 17 ). The output control unit  91  may control the output of the power unit  50  based on at least one of the current position PS of the ship  200  obtained by the positional information obtainment unit  93 , distance between any of one or more ports where the ship is anchored and the current position PS (the distance dd 2  in  FIG. 17 , for example), and at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . This allows the exhaust gas treatment apparatus for ships  100  to control the remaining capacity RM 1  and the remaining capacity RM 2 . This allows the exhaust gas treatment apparatus for ships  100  to prevent the total capacity WM from reaching the capacity C 1  of the first storage unit  82  and to easily prevent the total capacity of the second discharged material  47 - 2  from reaching the capacity C 2  of the second storage unit  83  before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example). 
     The heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  based on at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . The heating unit  75  may control the heating of at least one of the first storage unit  82 , the second storage unit  83 , and the separation unit  81  based on at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . 
     When the remaining capacity RM 1  is equal to or greater than the threshold value th 1 , the heating unit  75  may heat the first storage unit  82 . As mentioned above, when the heating unit  75  heats the first storage unit  82 , the total capacity WM of the first discharged material  47 - 1  is easily reduced. Therefore, the heating unit  75  is configured to heat the first storage unit  82 , so that the exhaust gas treatment apparatus for ships  100  can easily prevent the total capacity from reaching the capacity C 1  of the first storage unit  82  (prevent the remaining capacity RM 1  from becoming zero) before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example). When the remaining capacity RM 1  is less than the threshold value th 1 , the heating unit  75  may not or may heat the first storage unit  82 . 
     When the remaining capacity RM 2  is equal to or greater than the threshold value th 2 , the heating unit  75  may heat the second storage unit  83 . As mentioned above, when the heating unit  75  heats the second storage unit  83 , the total capacity of the second discharged material  47 - 2  is easily reduced. Therefore, the heating unit  75  is configured to heat the second storage unit  83 , so that the exhaust gas treatment apparatus for ships  100  can easily prevent the total capacity of the second discharged material  47 - 2  from reaching the capacity C 2  of the second storage unit  83  (prevent the remaining capacity RM 2  from becoming zero) before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example). When the remaining capacity RM 2  is less than the threshold value th, the heating unit  75  may not or may heat the second storage unit  83 . 
     In the exhaust gas treatment apparatus for ships  100  in this example, based on at least one of the remaining capacity RM 1  and the remaining capacity RM 2 , the heating unit  75  may control the heating of at least one of the first storage unit  82  and the second storage unit  83  and the output control unit  91  may control the output of the power unit  50 . This allows the exhaust gas treatment apparatus for ships  100  to more easily prevent the total capacity WM from reaching the capacity C 1  of the first storage unit  82  as well as the capacity of the second discharged material  47 - 2  from reaching the capacity C 2  of the second storage unit  83  before the ship  200  arrives in a port where it is to be anchored (the port B in  FIG. 17 , for example) than when the heating unit  75  controls the heating of at least one of the first storage unit  82  and the second storage unit  83  or the output control unit  91  controls the output of the power unit  50 . 
     When the ship  200  is navigating the first sea area A 1 , the output control unit  91  may control the output of the power unit  50  based on at least one of the current position PS of the ship  200 , distance between the current position PS and the second sea area A 2  (the distance d 3  in  FIG. 18 , for example), and at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . This allows the exhaust gas treatment apparatus for ships  100  to prevent the remaining capacity RM 1  from reaching a capacity M 1  of the first storage unit  82  and to prevent the remaining capacity RM 2  from reaching a capacity M 2  of the second storage unit  83  before the ship  200  enters the second sea area A 2 . 
     When the ship  200  is navigating the second sea area A 2 , the output control unit  91  may control the output of the power unit  50  based on at least one of the current position PS of the ship  200 , distance between the current position PS and the first sea area A 1  (the distance d 4  in  FIG. 19 , for example), and at least one of the remaining capacity RM 1  and the remaining capacity RM 2 . This allows the exhaust gas treatment apparatus for ships  100  to prevent the remaining capacity RM 1  from reaching a capacity M 1  of the first storage unit  82  and to prevent the remaining capacity RM 2  from reaching a capacity M 2  of the second storage unit  83  before the ship  200  enters the first sea area A 1 . 
     While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be contained in the technical scope of the invention. 
     The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method illustrated in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order. 
     (Item 1) 
     An exhaust gas treatment apparatus for ships comprising: 
     a reaction tower supplied with exhaust gas containing particle matter and with liquid for treating the exhaust gas and configured to discharge exhausted liquid obtained by treating the exhaust gas; and 
     a heating unit configured to heat discharged material containing the exhausted liquid to evaporate at least a part of moisture contained in the discharged material. 
     (Item 2) 
     The exhaust gas treatment apparatus for ships according to item 1, further comprising a first storage unit configured to store first one of the discharged material containing the particle matter removed from the exhausted liquid and a part of the exhausted liquid, wherein 
     the heating unit is configured to heat the first storage unit. 
     (Item 3) 
     The exhaust gas treatment apparatus for ships according to item  1 , further comprising a second storage unit configured to store second one of the discharged material containing the exhausted liquid from which at least a part of the particle matter has been removed, wherein 
     the heating unit is configured to heat the second storage unit. 
     (Item 4) 
     The exhaust gas treatment apparatus for ships according to item 1, further comprising: a first storage unit configured to store first one of the discharged material containing the particle matter removed from the exhausted liquid and a part of the exhausted liquid; and a second storage unit configured to store second one of the discharged material containing the exhausted liquid from which at least a part of the particle matter has been removed, wherein 
     the heating unit is configured to heat at least one of the first storage unit and the second storage unit. 
     (Item 5) 
     The exhaust gas treatment apparatus for ships according to item 4, wherein 
     the heating unit is configured to heat the first storage unit and the second storage unit respectively at a first temperature and a second temperature, and 
     the first temperature is higher than the second temperature. 
     (Item 6) 
     The exhaust gas treatment apparatus for ships according to item 4 or 5, wherein 
     the heating unit is configured to heat the first storage unit and the second storage unit respectively for a first period and a second period, and 
     the first period is longer than the second period. 
     (Item 7) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 6, wherein 
     the first storage unit has a plurality of storage tanks for storing the first discharged material, and 
     the heating unit is configured to control, based on a content rate of moisture contained by first one of the discharged material stored in each of the plurality of storage tanks, temperature at which each of the plurality of storage tanks is heated. 
     (Item 8) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 7, further comprising a separation unit introduced with the exhausted liquid and configured to separate the moisture contained in the exhausted liquid and the particle matter, wherein 
     the particle matter separated by the separation unit is introduced into the first storage unit. 
     (Item 9) 
     The exhaust gas treatment apparatus for ships according to item 8, wherein the heating unit is configured to heat the first storage unit at a first temperature and to heat the separation unit at a third temperature higher than the first temperature. 
     (Item 10) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 9, further comprising: 
     a power unit configured to discharge the exhaust gas; and 
     a first heat exchanger, wherein the first heat exchanger is configured to exchange heat of the exhausted liquid and heat generated by the power unit. 
     (Item 11) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 10, further comprising a second heat exchanger configured to exchange the heat of the exhausted liquid and heat of first one of the discharged material. 
     (Item 12) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 11, further comprising a condensation unit, wherein 
     the heating unit is configured to heat the first storage unit, so that first vapor is generated which is obtained by evaporating at least a part of the exhausted liquid contained in the first discharged material stored in the first storage unit, 
     the heating unit is configured to heat the second storage unit, so that second vapor is generated which is obtained by evaporating at least a part of the exhausted liquid contained in the second discharged material stored in the second storage unit, and 
     the condensation unit is configured to condense at least one of the first vapor and the second vapor. 
     (Item 13) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 12, further comprising a switching control unit configured to make a switch between supply and non-supply of the exhausted liquid to the reaction tower. 
     (Item 14) 
     The exhaust gas treatment apparatus for ships according to item 13, wherein the heating unit is configured to start heating of at least one of the first storage unit and the second storage unit, before the switching control unit makes a switch such that the exhausted liquid is supplied to the reaction tower. 
     (Item 15) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 14,wherein 
     at least one of the first storage unit and the second storage unit has at least one of a gas supply unit, an air sending unit, and a pressure control unit, 
     when the first storage unit has at least one of the gas supply unit, the air sending unit, and the pressure control unit, the gas supply unit is configured to supply gas into first one of the discharged material, the air sending unit is configured to send air to first one of the discharged material, and the pressure control unit is configured to control pressure inside the first storage unit, and 
     when the second storage unit has at least one of the gas supply unit, the air sending unit, and the pressure control unit, the gas supply unit is configured to supply gas into second one of the discharged material, the air sending unit is configured to send air to second one of the discharged material, and the pressure control unit is configured to control pressure inside the second storage unit. 
     (Item 16) 
     The exhaust gas treatment apparatus for ships according to any one of items 4 to 15, wherein 
     the reaction tower is mounted on a ship, and 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on a navigation schedule of the ship. 
     (Item 17) 
     The exhaust gas treatment apparatus for ships according to item 16, wherein the heating unit is configured to heat the first storage unit in at least one of before the ship arrives in port and while the ship is anchored in port. 
     (Item 18) 
     The exhaust gas treatment apparatus for ships according to item 16 or 17, wherein the heating unit is configured to heat the second storage unit before the ship leaves port. 
     (Item 19) 
     The exhaust gas treatment apparatus for ships according to any one of items 16 to 18, further comprising a positional information obtainment unit configured to obtain a current position of the ship, wherein 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on the current position of the ship obtained by the positional information obtainment unit. 
     (Item 20) 
     The exhaust gas treatment apparatus for ships according to item 19, wherein 
     the ship is configured to navigate a first sea area where a regulation value of a concentration of the particle matter contained in the exhaust gas discharged from the reaction tower is a first concentration and a second sea area where the regulation value of the concentration is a second concentration lower than a first concentration, and 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit before the ship navigates the second sea area. 
     (Item 21) 
     The exhaust gas treatment apparatus for ships according to item 19, wherein 
     the ship is configured to navigate a first sea area where a regulation value of a concentration of the particle matter contained in the exhaust gas discharged from the reaction tower is a first concentration and a second sea area where the regulation value of the concentration is a second concentration lower than a first concentration, and 
     while the ship is navigating the second sea area, the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on distance between the second sea area and the first sea area. 
     (Item 22) 
     The exhaust gas treatment apparatus for ships according to any one of items 19 to 21, further comprising: 
     a power unit configured to discharge the exhaust gas, 
     an output control unit configured to control output of the power unit, and 
     a remaining capacity obtainment unit configured to obtain at least one of a remaining capacity of the first storage unit and a remaining capacity of the second storage unit, wherein 
     the output control unit is configured to control the output of the power unit based on at least one of the remaining capacity of the first storage unit and the remaining capacity of the second storage unit obtained by the remaining capacity obtainment unit. 
     (Item 23) 
     The exhaust gas treatment apparatus for ships according to any one of items 19 to 21, further comprising a remaining capacity obtainment unit configured to obtain at least one of a remaining capacity of the first storage unit and a remaining capacity of the second storage unit, wherein 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on at least one of the remaining capacity of the first storage unit and the remaining capacity of the second storage unit obtained by the remaining capacity obtainment unit. 
     (Item 24) 
     The exhaust gas treatment apparatus for ships according to item 23, further comprising: 
     a power unit configured to discharge the exhaust gas; and 
     an output control unit configured to control output of the power unit, wherein 
     the output control unit is configured to control the output of the power unit based on at least one of the remaining capacity of the first storage unit and the remaining capacity of the second storage unit obtained by the remaining capacity obtainment unit. 
     (Item 25) 
     The exhaust gas treatment apparatus for ships according to item 22 or 24, wherein the output control unit is configured to control the output of the power unit based on at least one of the current position of the ship obtained by the positional information obtainment unit, distance between any of one or more ports where the ship is anchored and the current position, and at least one of the remaining capacity of the first storage unit and the remaining capacity of the second storage unit obtained by the remaining capacity obtainment unit. 
     (Item 2-1) 
     The exhaust gas treatment apparatus for ships further includes a resupply unit configured to resupply the liquid, and 
     the storage unit is configured to control, based on a concentration of sulfur oxide ions contained in the exhausted liquid, an amount of the exhausted liquid stored in the storage unit per unit time and an amount of the liquid resupplied from the resupply unit to the discharged material per unit time. 
     (Item 2-2) 
     The heating unit is configured to heat the first storage unit and the third storage unit respectively for a first period and a third period, and 
     the third period is longer than the first period. 
     (Item 2-3) 
     The heating unit is configured to start heating the separation unit, before the switching control unit makes a switch such that the exhausted liquid is supplied to the reaction tower. 
     (Item 2-4) 
     The heating unit is configured to control heating of at least one of the first storage unit, the second storage unit, and the separation unit based on the current position of the ship obtained by the positional information obtainment unit. 
     (Item 2-5) 
     The heating unit is configured to approximate, based on distance between the current position and a port where the ship is anchored, a total amount of the discharged material discharged from the reaction tower, and 
     the heating unit is configured to control, based on the approximated total amount of the discharged material, at least one of the third temperature and the third period at and for which the separation unit is heated. 
     (Item 2-6) 
     When the ship is navigating the first sea area, the heating unit is configured to approximate a total amount of the discharged material based on distance between the current position of the ship and the second sea area, and 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on the approximated total amount of the discharged material. 
     (Item 2-7) 
     When the ship is navigating the second sea area, the heating unit is configured to approximate a total amount of the discharged material based on distance between the current position of the ship and the first sea area, and 
     the heating unit is configured to control the heating of at least one of the first storage unit and the second storage unit based on the approximated total amount of the discharged material. 
     EXPLANATION OF REFERENCES 
       10 : reaction tower,  11 : exhaust gas introduction port,  12 : trunk tube,  13 : branch tube,  14 : ejection unit,  15 : side wall,  16 : bottom surface,  17 : exhaust gas discharge port,  18 : gas treatment unit,  19 : liquid discharge port,  20 : discharge tube,  21 : discharge tube,  22 : circulation tube,  23 : introduction tube,  24 : introduction tube,  30 : exhaust gas,  31 : switching unit,  32 : exhaust gas introduction tube,  33 : switching unit,  34 : switching unit,  35 : particle matter,  36 : switching unit,  37 : gas,  38 : vapor,  40 : liquid,  41 : first vapor,  42 : second vapor,  43 : liquid,  46 : exhausted liquid,  47 : discharged material,  48 : discharged material,  50 : power unit,  60 : introduction pump,  61 : circulation pump,  70 : volumeric flow rate control unit,  72 : valve,  73 : storage unit,  74 : switching control unit,  75 : heating unit,  76 : resupply unit,  77 : cleaning agent charge unit,  78 : cleaning agent,  79 : flocculating agent,  80 : water storage unit,  81 : separation unit,  82 : first storage unit,  83 : second storage unit,  84 : storage tank,  85 : clarification unit,  86 : dehydration unit,  89 : gas,  90 : condensation unit,  91 : output control unit,  92 : remaining capacity obtainment unit,  93 : positional information obtainment unit,  94 : pressure control unit,  95 : air sending unit,  96 : gas supply unit,  97 : fuel supply unit,  98 : first heat exchanger,  99 : second heat exchanger,  100 : exhaust gas treatment apparatus for ships,  130 : economizer,  200 : ship