Patent Application
20180135805
The Embodiments of the present invention relate to Floating Storage and Regasification Units (FSRUs) and more particularly to an open loop vaporization system and method thereof.
An FSRU (Floating Storage and Regasification Unit) is primarily employed, as the name suggests, for loading on LNG (Liquefied Natural Gas) for storage in on-board cargo tanks prior to conversion/regasification and delivery of NG (Natural Gas) to pipelines and onshore facilities.
Regasification is a process of converting liquefied natural gas (LNG) at approximately −162° C. (−260° F.) temperature back to natural gas at atmospheric temperature. For this process, seawater at higher ambient temperature relative to the LNG is used as the heat source medium. The FSRU intends to utilize an open loop system, where in, seawater surrounding the unit is circulated through the regasification module after which the colder seawater is discharged back to the open sea. The overboard disposal of the colder seawater has to be in compliance with the EPA (Environmental Protection Agency) and must meet requirements of the local authorities as well.
EPA (EPA-842-R-99-001) stipulates that the difference in temperature from influent sea water to effluent sea water is usually between 10 deg. F. to 15 deg. F., but the range can be as much as 5 deg. F. to 25 deg. F.
Environment, Health, and Safety Guidelines for Offshore Oil and Gas Development, published by World Bank Group on Jun. 5, 2015, state that the temperature of the effluent sea water should be within 3 degrees Celsius of ambient seawater temperature at the edge of the defined mixing zone, or if the mixing zone is not defined, within 100 meters of the discharge.
There have been a number of solutions suggested in this regard, some of which are listed below:
JP5254716B2 discloses a system for heating the effluent sea water of the re-gasification unit. The system uses waste steam from a steam turbine, in a steam condenser to reheat the effluent sea water.
KR101647462B1 discloses a system for heating the effluent sea water of the re-gasification unit. The system employs a scrubber in which exhaust gases generated from the vessel's internal combustion engine or internal combustion engines located off-shore, are used to heat the effluent sea water.
The aforesaid documents and other solutions may aim to provide open loop vaporization systems which are within regulations, however they still need employment of additional heating loops and complicated equipment such as the condenser and the scrubber, which may need significant amount of maintenance. Further, the waste steam and the exhaust gases may not always be available in sufficient quantity.
Therefore, there remains a need in the art for an open loop vaporization system and a method which does not suffer from above mentioned discrepancies.
However, there remains a need in the art for an improved open loop vaporization system and method, which is simple, cost-effective and efficient.
Any discussion of the background art throughout the specification should in no way be considered as an admission that such background art is prior art nor that such background art is widely known or forms part of the common general knowledge in the field.
According to a first aspect of the present invention, an open loop vaporization system is disclosed. The open loop vaporization system comprises a regasification module having an influent side and an effluent side, a plurality of auxiliary pumps configured to draw sea water from a plurality of sea chests, a first junction, the first junction having a primary first junction inlet, a secondary first junction inlet and a first junction outlet, a second junction, the second junction having a primary second junction inlet, a secondary second junction inlet and a second junction outlet, the first junction outlet being connected with the primary second junction inlet and the secondary second junction inlet being connected with the effluent side, a first three-way valve, the first three-way valve having a first three-way valve inlet, a primary first three-way valve outlet and a secondary first three-way valve outlet, a throttling valve having a valve inlet and a valve outlet, the valve inlet being connected in line with the plurality of auxiliary pumps and the valve outlet being connected with the primary first junction inlet, a control module with a controller network, a first temperature sensor connected with the piping at the effluent side. Further, the throttling valve and the plurality of auxiliary pumps are configured to be actuated by the control module through the controller network. Further, the first three-way valve and the throttling valve are temperature controlled. Further, the first junction, the second junction and the first three-way valve form a loop. Further, the regasification module is configured to convert Liquefied Natural Gas (LNG) stored on board an FSRU into natural gas using heat from influent sea water coming in from the influent side, giving out effluent sea water from the effluent side. Further, the first three-way valve inlet is configured to receive the effluent sea water leaving the regasification module, through the second junction. Further, the first temperature sensor is configured to measure a first temperature value in the piping at the effluent side of the regasification module and transmit the first temperature value to the control module. Further, the control module is configured to open the primary first three-way valve outlet and discharge the effluent sea water overboard through the overboard line, if the received first temperature value is higher than a reference temperature value.
In accordance with an embodiment of the invention, the control module is further configured to close the primary first three-way valve outlet and actuate the at least one of the plurality of auxiliary pumps, drawing in influent sea-water from the plurality of sea-chests, if the received first temperature value is lower than the reference temperature value. Further, the secondary first three-way valve outlet is configured to allow the effluent sea water to exit out of the first three-way valve and mix with the influent sea water at the first junction, creating an effluent-influent mix. Further, the first junction outlet is configured to allow the effluent-influent mix to leave the first junction and enter the second junction through the primary second junction inlet.
In accordance with an embodiment of the invention, the second junction is configured to mix the additional effluent sea water entering through the secondary second junction inlet with the effluent-influent mix.
In accordance with an embodiment of the invention, the second junction outlet is configured to allow the effluent-influent mix to leave the second junction and reach the first three-way valve inlet.
In accordance with an embodiment of the invention, the system further comprises an auxiliary temperature sensor connected with the piping at the first three-way valve inlet. Further, the auxiliary temperature sensor is configured to measure an auxiliary temperature value in the piping at the first three-way valve inlet and transmit the auxiliary temperature value to the control module. Further, the control module is further configured to open the primary first three-way valve outlet and discharge the effluent-influent mix overboard, if the auxiliary temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the control module is further configured to close the primary first three-way valve outlet, if the auxiliary temperature value is lower than the reference temperature value.
In accordance with an embodiment of the invention, the loop is configured to allow the effluent-influent nix to re-circulate through the secondary first three-way valve outlet, receiving additional influent sea water from the throttling valve at the first junction, until the auxiliary temperature value exceeds the reference temperature value.
According to a second aspect of the present invention, an open loop vaporization system is disclosed. The open loop vaporization system comprises a plurality of ballast tanks, a plurality of auxiliary pumps connected with a plurality of auxiliary tank outlets of the plurality of respective ballast tanks, a regasification module having an influent side and an effluent side, a first three-way valve, the first three-way valve having a first three-way valve inlet, a primary first three-way valve outlet and a secondary first three-way valve outlet, the effluent side is connected with the first three-way valve inlet of the first three-way valve, a second three-way valve, the second three-way valve having a second three-way valve inlet, a primary second three-way valve outlet and a secondary second three-way valve outlet, the second three-way valve inlet being connected with the plurality of auxiliary pumps, the primary second three-way valve outlet being connected with the overboard line of the piping and the secondary second three-way valve outlet being connected with the plurality of auxiliary tank inlets, a control module with a controller network, a first temperature sensor connected with the piping at the first three-way valve inlet, a second temperature sensor connected with the piping at the second three-way valve inlet. Further, the regasification module is configured to convert Liquefied Natural Gas (LNG) stored on board an FSRU into natural gas using heat from influent sea water coming in from the influent side, giving out effluent sea water from the effluent side. Further, the first three-way valve and second three-way valve are temperature controlled and are configured to be actuated by the control module through the controller network. Further, the first three-way valve inlet is configured to receive the effluent sea water leaving through the effluent side. Further, the first temperature sensor is configured to measure the first temperature value and transmit the first temperature value to the control module. Further, the control module is configured to open the primary first three-way valve outlet and discharge the effluent sea water overboard through the overboard line, if the first temperature value is higher than a reference temperature value.
In accordance with an embodiment of the invention, the control module is further configured to close the primary first three-way valve outlet, if the first temperature value is lower than the reference temperature value. Further, the plurality of ballast tanks is configured to receive the effluent sea through the plurality of auxiliary tank inlets, exiting the secondary first three-way valve outlet. Further, the plurality of auxiliary pumps is configured to pump the effluent-ballast sea water mixture, through the plurality of auxiliary tank outlets. Further, the second three-way valve inlet is configured to receive the effluent-ballast sea water mixture. Further, the second temperature sensor is configured to measure a second temperature value in the piping and transmit the second temperature value to the control module. Further, the control module is configured to open the primary second three-way valve outlet and discharge the effluent-ballast sea water mixture overboard, if the second temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the control module is further configured to close the primary second three-way valve outlet and allow the effluent-ballast sea water mixture to exit through the secondary second three-way valve outlet and enter the plurality of ballast tanks through the plurality of auxiliary tank inlets, if the second temperature value is lower than the reference temperature value.
According to a third aspect of the present invention, there is provided an open loop vaporization system, comprising, a first heat exchanger provided inside a first ballast tank of a plurality of ballast tanks, the first heat exchanger having a first heat exchanger inlet and a first heat exchanger outlet, a plurality of auxiliary pumps connected with the first heat exchanger inlet, a regasification module having an influent side (1301) and an effluent side, a first three-way valve, the first three-way valve having a first three-way valve inlet, a primary first three-way valve outlet and a secondary first three-way valve outlet, the effluent side being connected with the first three-way valve inlet of the first three-way valve, the primary first three-way valve outlet being connected with an overboard line of piping, the secondary first three-way valve outlet being connected with the plurality of auxiliary pumps, a third three-way valve, the third three-way valve having a third three-way valve inlet, a primary third three-way valve outlet and a secondary third three-way valve outlet, the third three-way valve inlet being connected with the first heat exchanger outlet and the primary third three-way valve outlet being connected with the overboard line of the piping, a first temperature sensor connected with the piping at the first three-way valve inlet, a third temperature sensor connected with the piping at the third three-way valve inlet, a control module with a controller network. Further, the regasification module is configured to convert Liquefied Natural Gas (LNG) stored on board the FSRU, into natural gas, using heat from influent sea water coining in from the influent side, giving out effluent sea water from the effluent side. Further, the first three-way valve inlet is configured to receive the effluent sea water leaving from the effluent side of the regasification module. Further, the first temperature sensor is configured to measure a first temperature value in the piping and transmit the first temperature value to the control module. Also, the control module is configured to open the primary first three-way valve outlet and discharge the effluent sea water overboard through the overboard line, if the first temperature value is higher than a reference temperature value.
In accordance with an embodiment of the invention, the control module is configured to close the primary first three-way valve outlet and open the secondary first three-way valve outlet, if the first temperature value is lower than the reference temperature value. Further, the plurality of auxiliary pumps is configured to pump the effluent sea water into the first heat exchanger through the first heat exchanger inlet. Further, the third three-way valve inlet is configured to receive the effluent sea water leaving the first heat exchanger. Further, the third temperature sensor is configured to measure a third temperature value of the effluent sea water and transmit the third temperature value to the control module. Further, the control module is configured to open the primary third three-way valve outlet and discharge the effluent sea water leaving the first heat exchanger, overboard, if the third temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the system further comprises a second heat exchanger provided inside a second ballast tank of the plurality of ballast tanks, the second heat exchanger having a second heat exchanger inlet connected with the secondary third three-way valve outlet and a second heat exchanger outlet. Further, the control module is configured to open the secondary third three-way valve outlet and allow the effluent sea water to enter into the second heat exchanger at the second heat exchanger inlet, if the third temperature value is lower than the reference temperature value.
In accordance with an embodiment of the invention, the further comprises a fourth three-way valve, the fourth three-way valve having a fourth three-way valve inlet, a primary fourth three-way valve outlet and a secondary fourth three-way valve outlet, the fourth three-way valve inlet being connected with the second heat exchanger outlet and the primary fourth three-way valve outlet being connected with the overboard line of the piping, a fourth temperature sensor connected with the piping at the fourth three-way valve inlet. Further, the fourth three-way valve inlet is configured to receive the effluent sea water leaving the second heat exchanger. Further, the fourth temperature sensor is configured to measure a fourth temperature value of the effluent sea water and transmit the fourth temperature value to the control module. Further, the control module is configured to open the primary fourth three-way valve outlet and discharge the effluent sea water leaving the second heat exchanger, overboard, if the fourth temperature value is higher than the reference temperature value.
According to a fourth aspect of the present invention, there is provided a method of open loop vaporization, comprising steps of converting Liquefied Natural Gas (LNG) stored on board an FSRU into natural gas using heat from influent sea water coming in from influent side, giving out effluent sea water from an effluent side, by a regasification module, measuring a first temperature value of the effluent sea water, in piping, at the effluent side of the regasification module, opening a primary first three-way valve outlet of a first three-way valve and discharging the effluent sea water overboard through an overboard line, if the first temperature value is higher than a reference temperature value, closing the primary first three-way valve outlet and actuating a throttling valve and at least one of a plurality of auxiliary pumps for drawing in influent sea-water from a plurality of sea-chests, if the received first temperature value is lower than the reference temperature value, allowing the effluent sea water to exit out of the first three-way valve and mix with the influent sea water at a first junction, creating an effluent-influent mix, measuring an auxiliary temperature value of the effluent-influent mix, in the piping at the first three-way valve inlet and opening the primary first three-way valve outlet and discharging the effluent-influent mix overboard through the overboard line, if the auxiliary temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the method further comprises a step of closing the primary first three-way valve outlet, if the auxiliary temperature value is lower than the reference temperature value and allowing the effluent-influent mix to re-circulate through a secondary first three-way valve outlet, receiving additional influent sea water from the throttling valve at the first junction, until the auxiliary temperature value exceeds the reference temperature value.
According to a fifth aspect of the present invention, there is provided a method of open loop vaporization, comprising steps of convening Liquefied Natural Gas (LNG) stored on board an FSRU into natural gas using heat from influent sea water coming in from influent side, giving out effluent sea water from effluent side, by a regasification module, receiving the effluent sea water leaving through the effluent side at a first three-way valve inlet of a first three-way valve and measuring a first temperature value of the effluent sea water, in piping, at the first three-way valve inlet, opening a primary first three-way valve outlet of the first three-way valve and discharging the effluent sea water overboard through an overboard line, if the first temperature value is higher than a reference temperature value, closing primary first three-way valve outlet, if the first temperature value is lower than the reference temperature value and receiving the effluent sea-water exiting a secondary first three-way valve outlet of a first three-way valve, in a plurality of ballast tanks through a plurality of auxiliary tank inlets, creating an effluent-ballast sea water mixture, pumping the effluent-ballast sea water mixture, through a plurality of auxiliary tank outlets and receiving the effluent-ballast sea water mixture in a second three-way valve inlet of a second three-way valve, measuring a second temperature value of the effluent-ballast sea water mixture, in the piping at the second three-way valve inlet and opening a primary second three-way valve outlet of the second three-way valve and discharging the effluent-ballast sea water mixture overboard, if the second temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the method further comprises a step of closing the primary second three-way valve outlet and allowing the effluent-ballast sea water mixture to exit through the secondary second three-way valve outlet of the second three-way valve and enter the plurality of ballast tanks through the plurality of auxiliary tank inlets, if the second temperature value is lower than the reference temperature value.
According to a sixth aspect of the present invention, there is provided a method of open loop vaporization, comprising steps of converting Liquefied Natural Gas (LNG) stored on board FSRU into natural gas using heat from influent sea water coming in from an influent side, giving out effluent sea water from the effluent side, by a regasification module, receiving the effluent sea water leaving through the effluent side at a first three-way valve inlet of a first three-way valve and measuring a first temperature value of the effluent sea water, in piping, at the first three-way valve inlet, opening a primary first three-way valve outlet of the first three-way valve and discharging the effluent sea water overboard through an overboard line, if the first temperature value is higher than a reference temperature value, pumping the effluent sea water into a first heat exchanger through a first heat exchanger inlet and receiving the effluent sea water leaving the first heat exchanger at a third three-way valve inlet of a third three-way valve, measuring a third temperature value of the effluent sea water leaving the first heat exchanger, at the third three-way valve inlet and opening a primary third three-way valve outlet of the third three-way valve and discharging the effluent sea water leaving the first heat exchanger, overboard, if the third temperature value is higher than the reference temperature value.
In accordance with an embodiment of the invention, the method further comprises steps of opening the secondary third three-way valve outlet and allowing the effluent sea water to enter into a second heat exchanger at a second heat exchanger inlet, if the third temperature value is lower than the reference temperature value, measuring a fourth temperature value of the effluent sea water leaving the second heat exchanger, at the fourth three-way valve inlet and opening a primary fourth three-way valve outlet of the fourth three-way valve and discharging the effluent sea water leaving the second heat exchanger, overboard, if the fourth temperature value is higher than the reference temperature value.
At least one example of the invention will be described with reference to the accompanying drawings, in which:
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may have been referred by examples, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawing illustrates only typical examples of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective examples.
These and other features, benefits, and advantages of the present invention will become apparent by reference to the following text figure, with like reference numbers referring to like structures across the views, wherein:
It should be noted that the same numeral represents the same or similar elements throughout the drawings.
Throughout this specification, unless the context requires otherwise, the words “comprise”, “comprises” and “comprising” will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements.
Any one of the terms: “including” or “which includes” or “that includes” as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others.
The exemplary Floating Storage and Regasification Unit (FSRU) (100) as shown in
Additionally, the FSRU (100) comprises a regasification module (130) having an influent side (1301) and an effluent side (1302) and a control module (140) as shown in
Further the system (200) comprises a first junction (250). As shown in
Further, the system (200) comprises a first three-way valve (230). The first three-way valve (230) is temperature controlled. As shown in
In use, the effluent sea-water leaving the regasification module (130) reaches the first three-way valve inlet (2301) through the second junction (260). The first temperature sensor (240) measures a first temperature value in the piping (150) at the effluent side (1302) of the regasification module (130) and transmits the first temperature value to the control module (140). If the first temperature value is higher than a reference temperature value preset in the control module (140) as per local maritime regulations, the primary first three-way valve outlet (2302) is opened by the control module (140) and the effluent sea water is allowed to be discharged overboard through the overboard line. If, however, the first temperature value is lower than the reference temperature value, the primary first three-way valve outlet (2302) is kept closed and at least one of the plurality of auxiliary pumps (210) are actuated from by the control module (140), drawing in influent sea-water from the plurality of sea-chests (122). The operating point (head and flow) along a pump curve of the plurality of auxiliary pumps (210) depends on the first temperature value. The throttling valve (220) is actuated by the control module (140) to regulate flow of the influent sea water in the piping (150). The throttling valve (220) is proportionally controlled by the control module (140) to ensure that just the right amount of influent sea water required is made to mix with the effluent sea water.
The effluent sea water is exited out of the secondary first three-way valve outlet (2303) and made to mix with the influent sea water at the first junction (250), creating an effluent-influent mix. The effluent-influent mix leaves the first junction (250) at the first junction outlet (2503) and enters the second junction (260) through the primary second junction inlet (2601). Additional effluent sea water entering through the secondary second junction inlet (2602) may be mixed with the effluent-influent mix at the second junction (260).
The effluent-influent mix leaves the second junction (260) through the second junction outlet (2603) and reaches the first three-way valve inlet (2301). The auxiliary temperature sensor (245) measures an auxiliary temperature value in the piping (150) at the first three-way valve inlet (2301) and transmits the auxiliary temperature value to the control module (140). If the auxiliary temperature value is higher than the reference temperature value, the control module (140) opens the primary first three-way valve outlet (2302) and allows the effluent-influent mix to be discharged overboard. If, however, the auxiliary temperature value is lower than the reference temperature value, the primary first three-way valve outlet (2302) is kept closed by the control module (140) and the effluent-influent mix is re-circulated inside the loop, through the secondary first three-way valve outlet (2303), receiving additional influent sea water from the throttling valve (220) at the first junction (250), until the auxiliary temperature value exceeds the reference temperature value.
Once the auxiliary temperature value exceeds the reference temperature value, the primary first three-way valve outlet (2302) is opened by the control module (140) and the influent-effluent mix is allowed to be discharged overboard. However, the proportional control of the throttling valve (220) ensures optimal performance of the system (200) by minimizing or eliminating recirculation of the effluent-influent mix inside the loop. This system allows for instantaneous mixing of the influent and effluent sea water inside the piping (150) for a homogenous mixture of the cooler and warmer sea waters delivering a single stream with consistent and the acceptable discharge temperature.
Further, the system (300) comprises the plurality of auxiliary pumps (210) connected to a plurality of auxiliary tank outlets (1104) (for e.g. 1104a, 1104b, 1104c . . . 1104x, 1104y) (not shown in
In use, the effluent sea water leaves the effluent side (1302) and reaches the first three-way valve inlet (2301). The first temperature sensor (240) measures the first temperature value and transmits the first temperature value to the control module (140). If the first temperature value is higher than the reference temperature value, the primary first three-way valve outlet (2302) is kept open by the control module (140) and the effluent sea water is allowed to be discharged overboard through the overboard line. If, however, the first temperature value is lower than the reference temperature value, the primary first three-way valve outlet (2302) is kept closed by the control module (140). The effluent sea water then exits through the secondary first three-way valve outlet (2303) and enters the plurality of ballast tanks (110) through the plurality of auxiliary tank inlets (1103). The plurality of ballast tanks (110) act as holding tanks. In accordance with an embodiment of the invention, the plurality of ballast tanks (110) are of double bottom ballast type. There is a minimum level of 1-1.5 m of ballast sea water in the double bottom ballast water tanks for all weather and met ocean conditions. The effluent sea water is dumped into the plurality of ballast tanks (110) which results in effluent-ballast sea water mixture. Additional influent sea water can be pumped or gravity fed into the plurality of ballast tanks to raise the overall temperature of the effluent-ballast sea water mixture until the temperature of the effluent-ballast sea water mixture is above the reference temperature value.
The effluent-ballast sea water mixture is then pumped by the plurality of auxiliary pumps (210) through the plurality of auxiliary tank outlets (1104). In accordance with an embodiment, the plurality of auxiliary tank outlets (1104) are positioned opposite to the plurality of ballast water inlets (1101) and the plurality of ballast water outlets (1102) for better mixing. The effluent-ballast sea water mixture then reaches the second three-way valve inlet (3101). The second temperature sensor (320) measures a second temperature value in the piping (150) and transmits the second temperature value to the control module (140). If the second temperature value is higher than the reference temperature value, the primary second three-way valve outlet (3102) is opened In the control module (140) and the effluent-ballast sea water mixture is discharged overboard.
If, however, the second temperature value is lower than the reference temperature value, the primary second three-way valve outlet (3102) is kept closed and the effluent-ballast sea water mixture exits through the secondary second three-way valve outlet (3103) and enters the plurality of ballast tanks (110) through the plurality of auxiliary tank inlets (1103). This cycle is repeated until the temperature of the effluent-ballast sea water mixture goes higher than the reference temperature value.
Further, a third three-way valve (420) as shown in
Returning to
The secondary third three-way valve outlet (4203) is connected to the second heat exchanger inlet (4101b). The second heat exchanger outlet (4102b) is in turn connected with the fourth three-way valve inlet (4401). Further, a fourth temperature sensor (450) is connected to the piping (150) at the fourth three-way valve inlet (4401). The primary fourth three-way valve outlet (4402) is connected with the overboard line. The secondary fourth three-way valve outlet (4403) is in turn connected with the first heat exchanger inlet (4101a). It is to be noted here that only two heat exchangers in two ballast tanks, viz., the first ballast tank (110a) and the second ballast tank (110b) having the respective first heat exchanger (410a) and the second heat exchanger (410b) with the third three-way valve (420) and the fourth three-way valve (440) have been presented here for sake of clarity of discussion. The set up can be extended to any number of ballast tanks provided with one or more heat exchangers each and three-way valves in between the ballast tanks, as per the demands of the system.
In use, when the effluent sea water leaves the effluent side (1302) of the regasification module (130), the effluent sea water reaches the first three-way valve inlet (2301). The first temperature sensor (240) measures the first temperature value in the piping (150) and transmits the first temperature value to the control module (140). If the first temperature value is higher than the reference temperature value, the control module (140) opens the primary first three-way valve outlet (2302) and the effluent sea water is discharged overboard through the overboard line. However, if in case the first temperature value is lower than the reference temperature value, the primary first three-way valve outlet (2302) is kept closed and the secondary first three-way valve outlet (2303) is opened by the control module (140). The effluent sea water is pumped by the plurality of auxiliary pumps (210) into the first heat exchanger (410a) through the first heat exchanger inlet (4101a). In accordance with an embodiment, the first heat exchanger (410a) and the second heat exchanger (410b) are submerged in at least 1 to 1.5 m of ballast sea water. The effluent sea water absorbs heat from the ballast sea water in the process. Additional influent sea water can be pumped or gravity fed into the plurality of ballast tanks (110).
The effluent sea water exits the first heat exchanger (410a) and reaches the third three-way valve inlet (4201). The third temperature sensor (430) measures a third temperature value of the effluent sea water and transmits the third temperature value to the control module (140). If the third temperature value is higher than the reference temperature value, then the control module (140) opens the primary third three-way valve outlet (4202) and the effluent sea water is discharged overboard. If, however, the third temperature value is lower than the reference temperature value, the control module (140) opens the secondary third three-way valve outlet (4203) and the effluent sea water enters the second heat exchanger (410b) at the second heat exchanger inlet (4101b). Here again, the effluent sea water absorbs heat from the ballast sea water in the process.
The effluent sea water exits the second heat exchanger (410b) and reaches the fourth three-way valve inlet (4401). The fourth temperature sensor (450) measures a fourth temperature value of the effluent sea water and transmits the fourth temperature value to the control module (140). If the fourth temperature value is higher than the reference temperature value, then the control module (140) opens the primary fourth three-way valve outlet (4402) and the effluent sea water is discharged overboard. If, however, the fourth temperature value is lower than the reference temperature value, the control module (140) opens the secondary fourth three-way valve outlet (4403) and the effluent sea water enters the first heat exchanger (410a) at the first heat exchanger inlet (4101a). The cycle is repeated until the temperature of the effluent sea water goes above the reference temperature value.
In accordance with an embodiment of the invention, at step 516, the primary first three-way valve outlet (2302) is closed, if the auxiliary temperature value is lower than the reference temperature value and the effluent-influent mix is allowed to re-circulate through the secondary first three-way valve outlet (2303), receiving the additional influent sea water from the throttling valve (220) at the first junction (250), until the auxiliary temperature value exceeds the reference temperature value.
In accordance with an embodiment of the present invention, at step 616, the primary second three-way valve outlet (3102) is closed and the effluent-ballast sea water mixture is allowed to exit through the secondary second three-way valve outlet (3103) of the second three-way valve (310) and enter the plurality of ballast tanks (110) through the plurality of auxiliary tank inlets (1103), if the second temperature value is lower than the reference temperature value.
In accordance with an embodiment of the present invention, at step 714, the secondary third three-way valve outlet (4203) is opened and the effluent sea water is allowed to enter into the second heat exchanger (410) at the second heat exchanger inlet (4101b), if the third temperature value is lower than the reference temperature value. At step 716, the fourth temperature value of the effluent sea water leaving the second heat exchanger (410b), is measured at the fourth three-way valve inlet (4401). At step 718, the primary fourth three-way valve outlet (4402) of the fourth three-way valve (440) is opened and the effluent sea water leaving the second heat exchanger is discharged overboard, if the fourth temperature value is higher than the reference temperature value.
It is to be noted that in all of the embodiments discussed above, the plurality of ballast pumps (124) may be used to support or replace the plurality of auxiliary pumps (210) during failure of the plurality of auxiliary pumps (210) or by design. Further, the embodiments have been described with minimum number of components required to enable the open loop vaporization system. Additional components such as additional valves, check valves, filters, sensors (including temperature differential sensors), controllers, field devices etc. may be employed in various locations of the piping (150) to enhance the overall reliability of the open loop vaporization system and method.
The open loop vaporization system offers the number of advantages. The system involves implementation of standard equipment such as pumps, valves and piping and does not require any complex piece of equipment. Further, the system is cost effective and efficient. Moreover, the system ensures the discharged sea water system is within the national and international guidelines to protect the marine environment. Therefore, the system discharges seawater at the temperature within the acceptable limits.
The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Examples and limitations disclosed herein are intended to be not limiting in any manner, and modifications may be made without departing from the spirit of the present disclosure. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the disclosure, and their equivalents, in which all terms are to be understood in their broadest possible sense unless otherwise indicated.
Various modifications to these embodiments are apparent to those skilled in the art front the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the embodiments shown along with the accompanying drawings but is to be providing broadest scope of consistent with the principles and the novel and inventive features disclosed or suggested herein. Accordingly, the disclosure is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present disclosure and appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62421889 | Nov 2016 | US |
