Ballast water treatment system

A ballast water treatment system has a source of hot water from the cooling water overboard discharge associated with the propulsion plant of a cargo or ship vessel. The heat exchangers are placed to receive ballast water from ballast tanks or in ballast tanks. A hot fluid system takes the heat from the overboard discharge and uses it to heat the ballast water as it is pumped through the heat exchangers.

This application claims the benefit of U.S. Provisional application Ser. 
No. 60/011,673 filed Feb. 14, 1996. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This application relates to systems for heating the ballast water of a 
ship. 
2. State of the Art 
Cargo vessels that are used for moving freight over water typically have a 
plurality of tanks that are used to retain fluids including ballast water. 
Ballast in the form of water is taken on as necessary to maintain the ship 
on an even keel and to control the center of buoyancy relative to the 
metacenter of the cargo vessel. Reference may be had to Principles of 
Naval Architecture, Vol. 1, written by H. E. Rossell and L. V. Chapman, 
published by the Society of Naval Architects and Marine Engineers (New 
York 1942), at pages 88, regarding ballast water tanks, fuel tanks, and 
the like. There is also discussion of the center of buoyancy relative to 
the metacenter of a ship and the various factors relating to the ability 
of a ship to right itself when it rolls or is otherwise not on an even 
keel. Discussion is also had about steps to maintain the ship on an even 
keel by use of systems to trim the vessel by moving water between or in 
and out of various ballast tanks. Reference may be also had to Design and 
Construction of Steel Merchant Ships, edited by D. Arnott, published by 
the Society of Naval Architects and Marine Engineers (New York 1955). 
Other vessels, in addition to cargo vessels, may use ballast water from 
time to time. For example, barges, passenger ships, naval ships, and the 
like may use ballast water to maintain an even keel when loads or cargo 
are taken on or removed from time to time and to offset the changes 
evolving from the use of fresh water, stores, fuel and the like. 
Vessels that take on ballast water into various ballast tanks do so by 
accepting water or taking water from the environs in which they are at the 
time it is needed. Thus, a vessel off-loading freight in a port may from 
time to time take on ballast water while tied to a pier or moored in that 
port. 
It is recognized that vessels taking on ballast water acquire in that 
ballast water local algae, zooplankton and other organisms that are extant 
in that particular locale. When the vessel moves to another port and takes 
on cargo or other loads, ballast water may be removed, thus delivering the 
algae, zooplankton and other organisms to the port (or other location) in 
which the vessel is then located. As a result, it is recognized that cargo 
vessels have been creating environmental problems by transporting various 
algae, zooplankton and organisms from one port to another. In order to 
control or minimize such transport in ballast water, vessels are requested 
to exchange harbor ballast water for open ocean water in order to control 
dispersal of fresh water organisms or organisms more locally oriented and 
found in ports that are not found in the open ocean environment. See A. 
Locke, D. Reid, H. van Leeuwen, W. Sprules, and J. Carlton, Ballast Water 
Exchange as a Means of Controlling Dispersal of Fresh Water Organisms by 
Ships (Can. J. Fish. Aquat. Sci. Vol. 50, 1993), at page 2086. 
It is understood that ballast water exchange, to the extent it is presently 
practiced, is not entirely effective. Some organisms can be retained 
within an empty ballast water tank for an extended period of time. 
Further, an exchange with open ocean salt water does not necessarily 
remove or eliminate all of the acquired organisms. Of course, many ships 
may not practice ballast water exchange as requested. 
Systems to eliminate organisms obtained in ports while loading or unloading 
cargo are desirable in order to minimize the increasing risk of 
environmental pollution. 
SUMMARY 
A system is provided by which the waste energy from the propulsion system 
of a vessel in the form of heat transferred to a heating fluid such as 
water is used to heat the ballast water and, in effect, pasteurize the 
ballast water to eliminate the microorganisms and other living creatures 
that may have entered or been entrained as the ballast water was taken on. 
The system includes a source and a supply of heating fluid that employ a 
plurality of valves in which the hot or heating fluid (such as water) is 
delivered to an inlet of a selected heat exchanger from the hot or heating 
fluid source. The hot or heating fluid source is preferably structured to 
extract heat from the system used to remove excess heat energy from the 
propulsion system of the vessel. In the absence of useful energy from the 
cooling water or if the energy from the cooling water is insufficient, an 
auxiliary source of energy, such as a boiler or heater, may be used as the 
hot fluid source. 
The water from the ballast tank may be pumped to one or more heat 
exchangers and returned to the ballast tank through a return after being 
heated to a desired temperature. Alternately, a heat exchanger may be 
placed in a ballast tank. The hot or heating fluid may be delivered to the 
heat exchanger in the ballast tank in order to raise the temperature of 
the ballast water in that tank. The heat exchanger is connected to the 
return so that the heating fluid can be transported to the heating fluid 
source.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
In reference to FIG. 1, the hot or heating fluid source 10 is shown 
interconnected to a hot or heating fluid header 12 or supply through a 
valve 14 to the inlet 15 of a heat exchanger 16. The heat exchanger 16 is 
shown as a sealed vessel with heat exchanging tubes 18 positioned therein. 
The heat exchanger 16 may be of the counterflow, cross-flow, or back-flow 
variety as desired in given applications. 
The valve 14 may be any conventional stop valve such as a ball valve or 
gate valve. The valve typically has a closed position represented by an 
"X" and then an open position, which is represented by the absence of an 
"X." That is, the valve 14 is here shown as a simple circle to reflect 
that it is open so that hot fluid from the source 10 is proceeding through 
the header 12 and the distribution line 20 to the heat exchanger 16. As 
stated, the hot or heating fluid passes through the heat exchanger coils 
18, through the outlet 19 and then to the discharge 21 through a discharge 
check valve 22 positioned to prevent back-flow into the heat exchanger 16. 
The heating fluid (now cooler) then proceeds through a thermostatically 
controlled solenoid valve 24 to a heating fluid return which includes 
return header 26 and then via a return line 28 to the fluid source 10, 
where it is processed to acquire more heat for redelivery through the heat 
exchanger 16. 
As can be seen in FIG. 1, a supply pump 30 may be provided in order to 
provide the hot or heating fluid at a desired flow rate and pressure. A 
pump isolation valve 32 is shown with a bypass valve 34 now closed (as 
represented by the X in the circle) to show that the hot fluid from the 
hot fluid source is supplied in the header 12 under pressure through valve 
14 and through the heat exchanger 16 to the return header 26. 
A separate booster pump or return pump 36 may be used together with the 
supply pump 30 or as the system pump without the supply line pump 30. The 
pump 36 may place a pressure on the system containing the hot or heating 
fluid as well as the return so that a pump such as pump 30 in the supply 
side is not necessary. As here shown, the return pump 36 is not operating 
with its discharge valve 38 closed. The bypass valve 40 is open. 
It may also be seen that a head tank 42 has been connected via a line 44 to 
the header 12. The head tank 42 is typically vented to the atmosphere and 
is provided to regulate the pressure of the heating fluid in the header 
12. A pressure above that provided by atmosphere may be desired in order 
to increase the temperature of the hot or heating fluid source above the 
boiling point of the fluid to permit greater increases in the enthalpy of 
the fluid and in turn greater increases in the amount of heat energy being 
delivered to the ballast water. 
An auxiliary energy source 46 is also shown. The auxiliary energy source 
may be a simple fossil fuel boiler or heater configured to supply fluid 
through a discharge valve 50 to the supply header 12. The auxiliary energy 
source may receive heating fluid from the return line 28 and a separate 
return line 52 via supply valve 54 or from the heating fluid source 10 via 
valve 55. The auxiliary energy source 46 may thus be operated as an 
alternate source of heating fluid or in series with the heating fluid 
source 10 to further increase the heat delivered to the heating fluid and 
in turn to the heat exchanger 16. 
It has been stated before that the valve 24 on the discharge of the heat 
exchanger is a thermostatically controlled solenoid valve. That is, the 
valve 24 may be of the type in which the flow rate of fluid through it is 
regulated by the temperature sensed by a temperature sensor 56 positioned 
in the discharge line 72 of the ballast water. 
As can be seen, ballast water may be supplied from a source thereof such as 
a ballast tank via a supply that includes an input line 58 and a supply 
pump 60. The input line 58 may be connected to a fluid system used for 
taking on and transferring ballast water. It may also be connected to the 
fuel system if the fuel system takes on compensating water to compensate 
for spent fuel. 
The supply pump has a bypass 62, which is here shown to be closed, and a 
discharge valve 64, which is shown open. The ballast water is then 
supplied via the supply header 66 to a heat exchanger supply line 68. The 
heat exchanger supply line 68 has an inlet control valve 70, which is here 
shown to be open. The ballast water then passes from an inlet 71 through 
the heat exchanger to an outlet 72. The outlet 72 has a discharge stop 
valve 74 as well as a temperature sensor 56 as hereinbefore noted. The 
discharge stop valve 74 allows the ballast water to return via a return 
header 76 to a return pump 78. 
The pump 78 has a discharge valve 80, which is here shown to be closed. 
Bypass valve 80 opens to reflect the fact that the ballast water passes 
around the pump 78 via the bypass line 82. A supply pump 60 may supply 
sufficient head to cause the ballast water to flow through the heat 
exchanger and back to the source of ballast water such as the ballast 
tank. Alternatively, return pump 78 may be used in lieu of a supply pump 
60. In some applications, both a supply pump 60 and a return pump 78 will 
be necessary. 
FIG. 1 also shows a second heat exchanger 86, which is connected to the 
source of hot or heating fluid 10 via line 12 and line 88 via supply valve 
90. The supply valve 90 is here shown closed to reflect the fact that the 
heat exchanger 86 is not "on line" and not in fact operating. The heat 
exchanger 86 is here shown to also have a plurality of interior tubes 92 
over or about which ballast water flows in order to extract the heat and 
increase in temperature. That is, the ballast water may be supplied via 
the supply header 66 and supply valve 94. The outlet 96 has a discharge 
stop valve 98 as well as a temperature sensor 100 connected to the 
discharge solenoid valve 102 in a manner comparable to that of heat 
exchanger 16. The discharge of hot or heating fluid from the heat 
exchanger 86 is effected through a discharge line 104 and a discharge 
check valve 106 into the hot or heating fluid return header 26. The 
discharge valve 102 is shown in a closed condition to prevent back-flow as 
well as to isolate the heat exchanger as desired. 
In operation, it can be seen that hot or heating fluid from the hot or 
heating fluid source 10 passes through the hot or heating fluid header 12 
and supply pump 30. Hot or heating fluid then passes through valve 14 and 
through heat exchanger 16 and the interior tubes thereof 18. The rate of 
flow is regulated by the discharge solenoid valve 24 based on the 
temperature sensed in the discharge of the ballast water 56. Although 
temperature control is here suggested, it is not required and may not be 
necessary if the user operates the system as a circulating system in which 
the temperature rises gradually as ballast water is circulated through the 
heat exchanger 16. 
The second heat exchanger 86 represents a second or, in turn, a plurality 
of additional heat exchangers which may be used at a different location(s) 
as desired, based on the particular vessel and location at hand. 
FIG. 1 also shows a heat exchanger being positioned within a ballast tank. 
More specifically, the hot or heating fluid may be supplied via the header 
12 through an isolation valve 108 and a supply valve 110 into a ballast 
tank 112 of a ship or cargo vessel 114. The heat exchanger consists of an 
inlet 111 and a plurality of tubes 116 positioned within the ballast tank 
112. The hot or heating fluid leaves the heat exchanger 116 via the outlet 
or discharge line 118 and a discharge check valve 120. A discharge stop 
valve 124 is also provided. The hot or heating fluid then returns via a 
return line 126 to the return header 26 for further transport to the 
source 10 for reheating. 
FIG. 2 shows a simplified steam propulsion system in which a steam 
generator 130 is provided to supply steam via a steam header 132 to a 
propulsion turbine 134. The propulsion turbine 134 supplies rotational 
torque via a shaft 136 to a reduction gear 138. The reduction gear 138 in 
turn powers the propeller 140 via a propeller shaft 142. The steam exiting 
the turbine via line 144 passes into a condenser 146. In traditional steam 
systems, the condenser acquires seawater through an induction and a 
discharge. The seawater passes through a bundle of tubes 148 over which 
the steam is projected to condense the steam. The steam in the form of 
condensate is transported via a condensate line 150 by a condensate pump 
152 to head tank 154 or a de-aerating feed tank as appropriate for the 
system. It may also pass directly to the main feed pump 156 for further 
delivery to the steam generator 130. Fuel and air may be supplied to the 
steam generator for combustion. Alternately, hot water may be supplied in 
a nuclear propulsion system. 
A fluid source 10 in FIG. 1 may, in fact, be a separate heat transfer means 
such as heat exchanger or tube bundle 158 positioned within the condenser 
in order to receive return hot or heating fluid and act as a supply of hot 
or heating fluid for delivery to the supply header 12 in FIG. 1. The 
seawater, which enters via the induction 160 and leaves via a seawater 
overboard 162, may pass through a separate heat exchanger 164 before 
passing overboard. The heat exchanger 164 receives the return of the hot 
or heating fluid via return line 28 and supplies the hot or heating fluid 
to the supply header 12. 
In FIG. 3, a gas turbine propulsion system is shown in which air and fuel 
are supplied to a gas turbine 170. The gas turbine burns the fuel/air mix, 
driving the turbine and producing a gas exhaust which is supplied via an 
exhaust line 172. A heat exchanger 174 which functions as a transfer means 
to transfer heat is positioned in or about the gas exhaust in order to 
heat the returned hot or heating fluid received via line 28 (FIG. 1) and 
acts as a hot or heating fluid source for the supply header 12. The gas is 
further exhausted via appropriate stack 176. The gas turbine, of course, 
drives a shaft 178, which turns a reduction gear 180. The reduction gear 
180 drives a propeller 182 via a propeller shaft 184. 
In FIG. 4, an engine 186 is shown which supplies shaft horsepower via 
output shaft 188 typically to a transmission 190 for further delivery of 
rotational or shaft horsepower to a propeller 192. The engine 186 is 
configured to have cooling water pass through jackets positioned about the 
cylinders to remove excess energy. The cooling water is supplied via an 
inlet line 194 through the cylinder jackets of the engine 186. The cooling 
water may be discharged directly into header 12 so that the diesel engine 
acts as a source of hot fluid. Alternatively, the cooling water discharge 
line 196 may pass through a heat exchanger or heat transfer means 
comparable to heat exchanger 164. The heat exchanger in turn may receive 
the return fluid via line 28 and supply hot or heating fluid to the supply 
header 12. 
It may be recognized that other propulsion systems may be used in a variety 
of different configurations. However, any propulsion system that uses fuel 
will produce excess energy which is typically discharged by a cooling 
water system. The energy is recovered from the cooling water system to 
heat the ballast water to a desired temperature. 
For example, for a ship delivering 17,500 shaft horsepower, approximately 
one-third of the total energy available to create that shaft horsepower is 
discharged in the form of heat. The ballast water system of the present 
invention seeks to capture a portion of the discharged heat in order to 
heat the ballast water to in turn kill the microorganisms and the other 
living things in the ballast water by raising the temperature to a point 
that the water no longer supports the organisms and other living things. 
For the 17,500 shaft horsepower ship, approximately 14,691,600 btu's per 
hour will be available from the discharge of the cooling water. If a ship 
had 13,400 tons of ballast water, the system would be able to raise the 
ballast water temperature approximately one-half degree per hour in ideal 
conditions. However, some energy is lost to ambient. Further, the heat 
exchangers which act as the hot fluid source are also less than 100% 
efficient. In turn, the temperature rise may be as little as 0.2.degree. 
per hour or approximately 41/2.degree. to 5.degree. F. per day for a 
system configured to heat all the water at once. This is a worst case 
scenario in that it presupposes that the ship is carrying no cargo, and 
that it is carrying its entire payload capacity as ballast. 
Under certain intended uses, it may be desirable to increase the heating 
rate. In these cases, it would be appropriate to add the earlier mentioned 
auxiliary source of heat, such as a boiler, which could use the same fuel 
as the main propulsion system. 
Other systems may be configured to heat one tank at a time or even a 
portion of one tank at a time. Further other systems may take ballast from 
one full tank, heat it and return it to an empty ballast tank.