System and method for cooling seawater for a heat exchange process

Abstract

The cooled seawater formed through interaction with the liquefied gas vaporizer can facilitate various types of heat exchange processes. Local environmental regulations often limit the extent to which the seawater can be cooled, since it is discharged as soon as the heat exchange occurs. The aforementioned problems can be addressed by a system including a liquefied gas vaporizer, a supply line configured to distribute seawater to the liquefied gas vaporizer, a collection reservoir below the liquefied gas vaporizer configured to collect the cooled seawater passing through the liquefied gas vaporizer, a heat exchanger in fluid communication with the collection reservoir, and a heat exchanger outlet line configured to discharge the heat-exchanged seawater to a sea body. The heat exchanger can be in direct or indirect thermal communication with a flow passage for air supplied to a gas engine or gas turbine, thereby changing the speed, power, or efficiency of the gas engine or gas turbine.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 201987, filed May 21, 2021, entitled "SYSTEM AND METHOD FOR COOLING SEAWATER FOR A HEAT EXCHANGE PROCESS," the entire contents of which are incorporated herein by reference.

[0002] Field The present disclosure relates to cooling seawater for heat exchange processes. [Background technology]

[0003] background Hot inlet air can reduce both the power output and efficiency of gas engines, including gas turbines. For example, an increase in inlet air temperature of about 40°F (e.g., 60°F (16°C) to 100°F (38°C)) can reduce the power output of a gas turbine by up to about 10% for industrial gas turbines and up to about 25% for aeroderivative turbines. Gas engine and gas turbine power output can also vary seasonally. The aforementioned problems can be mitigated to some extent by using an engine inlet air cooling (EIAC) system, sometimes referred to as a turbine inlet air cooling (TIAC) ​​system when applied to gas turbines. Many types of engine (turbine) inlet air cooling systems utilize vapor compression or vapor absorption chillers to reduce the temperature of the inlet air to provide less capacity fluctuation and more efficient operation of the gas engine or gas turbine. In the case of natural gas processing, another approach that utilizes the evaporation of liquefied natural gas is often more efficient. Other gas evaporation processes may also facilitate cooling of the engine or turbine inlet air as well.

[0004] Gas turbines are frequently utilized in natural gas processing, such as to compress natural gas streams to form liquefied natural gas (LNG) for transportation or other purposes. After formation of the LNG, the LNG may be transported to an onshore, coastal, or floating receiving terminal where it may undergo vaporization to reform the gaseous state. Seawater is a commonly used medium to facilitate heating of the LNG to reform the gaseous state. An open rack vaporizer (ORV) or other type of suitable gas vaporizer may facilitate heating of the LNG in contact with seawater to effect this phase change from its initial cryogenic liquid state. In the case of an ORV, a seawater stream may be sprayed or poured onto the LNG-containing tubes to facilitate heating and vaporization, and the cooled seawater may then be collected in a collection reservoir below the ORV for subsequent discharge into the ocean area. Vaporization of other liquefied gases may similarly facilitate the formation of cooled seawater. One difficulty with the aforementioned process is that environmental regulations may limit the temperature difference between the seawater being discharged and the seawater being fed to the ORV. Local regulations may limit the temperature difference at a specific location to approximately 5-7°C relative to the seawater outlet. This location may be determined by allowing some mixing with the surrounding seawater to occur before measuring the temperature at the specific location.

[0005] The cooling seawater obtained after heat exchange in the liquefied gas vaporizer can be utilized to facilitate various heat exchange operations, for example indirect cooling of inlet air supplied to a gas engine or gas turbine that may be involved in the LNG receiving process or a non-related process, especially when the ambient air temperature is high. The process is described in JP2000145476, in which the cooling seawater undergoes heat exchange with a warmer cooling fluid returning from a gas turbine, and the resulting heat-exchanged seawater is then recirculated upstream to facilitate further vaporization in the LNG vaporizer. The amount of seawater used to facilitate the vaporization of the LNG in the LNG vaporizer may exceed the amount required to facilitate the heat exchange downstream, and the excess cooling seawater must ultimately be discharged to a marine area. This practice may result in the discharge of a significant amount of cooling seawater having a temperature significantly lower than the local seawater temperature, at a relatively high discharge flow rate. The degree of inlet air cooling or other heat exchange that can be performed in this way is therefore regulated by the degree of seawater cooling that is initially performed, which is then limited by the above-mentioned environmental regulations regarding seawater discharge temperature difference. More specifically, conventional seawater-based cooling processes are unable to cool the inlet air temperature below the discharge temperature of the seawater, thereby reducing available power output and efficiency. Summary of the Invention

[0006] overview The present disclosure provides a system including a liquefied gas vaporizer, a seawater inlet connected to a supply line configured to distribute seawater to the liquefied gas vaporizer, a collection reservoir below the liquefied gas vaporizer configured to collect cooled seawater passing through the liquefied gas vaporizer, a heat exchanger in fluid communication with the collection reservoir via a reservoir outlet line, and a heat exchanger outlet line connected to a seawater outlet configured to discharge the heat exchanged seawater into a marine body. In some or other embodiments, the disclosed method may include supplying a liquefied gas stream to a liquefied gas vaporizer; introducing seawater into a supply line via a seawater inlet; distributing the seawater stream from the supply line to the liquefied gas vaporizer, thereby reducing a temperature of the seawater from a first temperature to a second temperature to form cooled seawater; collecting the cooled seawater at approximately the second temperature in a collection reservoir below the liquefied gas vaporizer; supplying the cooled seawater stream from the collection reservoir to a heat exchanger, where the cooled seawater is heated from the second temperature to a third temperature to form heat exchanged seawater; and removing the heat exchanged seawater stream from the heat exchanger via a heat exchanger outlet line. [Brief description of the drawings]

[0007] BRIEF DESCRIPTION OF THE DRAWINGS The following drawings are included to illustrate certain aspects of the present disclosure and should not be viewed as exclusive embodiments. The disclosed subject matter is capable of considerable modification, alteration, combinations, and equivalents in form and function, as will be apparent to those skilled in the art and having the benefit of this disclosure. [Figure 1] FIG. 1 is an illustration of a system and method for cooling inlet air supplied to a gas engine or gas turbine using seawater that has been cooled in a liquefied gas vaporizer. [Diagram 2] FIG. 1 is an illustration of a system and method for cooling the inlet air supplied to a gas engine or gas turbine using seawater cooled in a liquefied gas vaporizer divided into several compartments. [Diagram 3] FIG. 1 is an illustration of a system and method for cooling inlet air supplied to a gas engine or gas turbine using a secondary heat transfer fluid cooled by seawater that has been cooled in a liquefied gas vaporizer. [Figure 4] FIG. 1 is an illustration of a system and method for cooling inlet air supplied to a gas engine or gas turbine using a secondary heat transfer fluid cooled by seawater cooled in a liquefied gas vaporizer divided into several sections. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Detailed Description The present disclosure relates generally to heat exchange, and more particularly to methods and systems for cooling seawater to facilitate heat exchange, where the discharged seawater is maintained within a desired temperature differential. Seawater cooled in accordance with the disclosure herein can facilitate cooling of inlet air for gas engines and gas turbines to facilitate more efficient operation and improve the power output of the gas engines and gas turbines. As mentioned above, cooling of the inlet air for gas engines and gas turbines can facilitate higher and more consistent power output and more efficient operation of the gas engines and gas turbines. One way in which cooling of the inlet air can be achieved is by utilizing cooled seawater obtained from an LNG vaporizer to facilitate cooling of the inlet air after seawater-assisted vaporization of liquefied natural gas (LNG) in the LNG vaporizer, as described in JP2000145476. A difficulty with this conventional approach and similar inlet air cooling approaches is that the cooled seawater must ultimately be discharged into a marine area, and environmental regulations may limit the temperature difference between the discharged seawater and the seawater supplied to the LNG vaporizer. As a result, the amount of inlet air cooling that the seawater can provide is limited by the degree to which the seawater can be cooled during LNG vaporization. In many cases, the discharged seawater must not differ in temperature by more than about 5° C. from the seawater supplied to the LNG vaporizer (i.e., ambient seawater). Thus, a seawater inlet temperature of less than about 5°C temperature difference corresponds to the lowest possible temperature to which the engine inlet air can be cooled in a conventional inlet air cooling configuration. In practice, the inlet air temperature reached with seawater cooling may be higher than this minimum due to possible additional heat exchange operations. Depending on the ambient air temperature, this limitation may significantly constrain the engine / turbine capacity (power output) and efficiency.

[0009] The present disclosure provides various systems and methods that may alleviate the aforementioned difficulties. In particular, the present disclosure provides systems and methods for efficiently controlling the temperature of seawater discharged to the surrounding waters while using cooled seawater obtained from an LNG vaporizer, either directly or indirectly, to facilitate inlet air cooling for gas engines and gas turbines. In other words, the present disclosure provides a synergistic link between LNG vaporization and inlet air cooling for a gas engine or turbine. Vaporization of other cryogenic liquids, such as liquefied hydrogen, may also facilitate inlet air cooling. Furthermore, the cooled seawater formed in accordance with the disclosure herein may be utilized for heat exchange processes other than inlet air cooling. Advantageously, temperature control of the discharged seawater and the target inlet air temperature may be achieved with the disclosure herein without utilizing external heaters or cooling apart from those that may be used at other process locations. Instead, when necessary, temperature control may be achieved by mixing the heat exchanged seawater with a portion of the cooled seawater obtained from the LNG vaporizer and / or with seawater that failed to be cooled in the LNG vaporizer. Thus, the temperature of the discharged seawater may be increased or decreased as required by the operational needs. By controlling the discharge temperature of the heat exchanged seawater in the manner described above, the cooling seawater obtained from the LNG or similar liquefied gas vaporizer can be cooled more extensively, thereby allowing more effective inlet air cooling or related heat exchange to occur. Lower discharge flow rates can be advantageously achieved through the practice of the present disclosure. The cooling seawater provided to the inlet air or other heat exchange locations may be heated to a degree that satisfies seawater discharge temperature regulations. Further advantageously, the systems and methods of the present disclosure can more effectively accommodate seasonal temperature variations to equalize the performance of the gas engine or gas turbine. Additionally, the systems and methods of the present disclosure can facilitate greater power output and more efficient operation of gas engines and gas turbines, reducing the need for excess turbine capacity, which in many cases can reduce capital expenditures. Alternatively, by varying the temperature of the cooling water obtained from the LNG or similar liquefied gas vaporizer, the disclosed system and method may allow the capacity of a gas engine or gas turbine to be varied from its normal operating stage. For example, the cooling water temperature may be varied to adjust (increase or decrease) the power output in response to fluctuations in power demand. This feature may improve overall power efficiency and facilitate additional power output when required. Advantageously, temperature control of the cooling water obtained from the LNG or similar liquefied gas vaporizer may be achieved by simply varying the flow rate of seawater fed thereto.

[0010] As used herein, the term "natural gas" refers to multi-component gas obtained from crude oil wells (associated gas) or from underground gas reservoirs (non-associated gas). The composition and pressure of natural gas can vary quite significantly. A typical natural gas stream contains methane as a significant component, and sometimes as a major component. Natural gas streams may also contain ethane, higher molecular weight hydrocarbons (e.g., propane), and / or one or more acid gases. Small amounts of contaminants such as water, nitrogen, iron sulfides, wax, and crude oil may also be present. One or more of these components may be removed and / or reduced in concentration before the natural gas stream is processed. Liquefied natural gas (LNG) may contain primarily methane after undergoing processing. Preferably, the processed natural gas is substantially free of water and carbon monoxide. More preferably, the processed natural gas has a maximum C of about 1000 ppmv (parts per million by volume). 5+ content and a benzene content of less than about 1 ppmv. As used herein, the term "fuel gas" refers to a gaseous fuel that can be combusted to power a gas engine or gas turbine. As used herein, the term "gas engine" refers to any type of internal combustion engine that utilizes a gaseous fuel, such as hydrogen, natural gas, combinations thereof, and the like, to produce work. As used herein, the term "gas turbine" refers to a coupled gas compressor, combustor, and turbine in which air is compressed and combined with fuel, and the fuel is combusted to provide a hot pressurized gas stream. The hot pressurized gas stream is then fed to a turbine having a common shaft with the gas compressor. Excess energy in the form of exhaust gas(es) can be utilized to perform external work. Gas turbines include industrial gas turbines, aero-derivative gas turbines, or turbines operating in a mixed cycle.

[0011] As used herein, the term "cooling" refers to lowering and / or decreasing the temperature and / or internal energy of a substance by any suitable, desired, or necessary amount. In the case of air, cooling can also include condensation and / or removal of moisture from the air. As used herein, the term "heat exchanger" refers to any device capable of transferring thermal energy from one medium to another. Two heat exchangers may also be in thermal communication with each other to facilitate heat transfer. When a single heat exchanger is in direct contact with the medium requiring heat exchange, the disclosure herein classifies the heat exchanger as "direct." When two heat exchangers are in thermal communication with each other, particularly through the use of an intermediate heat transfer fluid, and the medium requiring heat exchange is in direct contact with the second heat exchanger but not with the first heat exchanger, the disclosure herein classifies the heat exchanger as "indirect." As used herein, the term "temperature differential" refers to the absolute value of the difference in temperature between a first location and a second location. Thus, the temperature of the second location can be higher, lower, or the same as the temperature of the first location. As used herein, the term "seawater" refers to water obtained from a marine environment or a location adjacent to a marine environment having at least some salinity, including, but not limited to, oceans, seas, bays, inlets, straits, brackish water estuaries, fresh water estuaries, salt water marshes and swamps, brackish water marshes and swamps, tidal marshes and swamps, fresh water marshes and swamps, etc. Of course, any of the embodiments described herein that utilize or discharge seawater into a marine body can equally be practiced with fresh water and discharge fresh water into a fresh water body. Furthermore, seawater does not necessarily have to be obtained directly from a marine source, as many locations near marine sources provide water that is functionally equivalent to seawater and can be used with the systems and methods herein.

[0012] Hereinafter, the embodiments of the present disclosure will be described in more detail with reference to the drawings. FIG. 1 is an illustration of a system and diagram for cooling inlet air supplied to a gas engine or gas turbine with seawater cooled in a liquefied gas vaporizer. As shown in FIG. 1, the system and method 100 includes an open rack liquefied gas vaporizer 102 or another type of liquefied gas vaporizer, such as an LNG vaporizer or a liquefied hydrogen vaporizer. The open rack liquefied gas vaporizer 102 includes tubes 104 in which a feed of liquefied gas (e.g., natural gas and / or hydrogen) undergoes vaporization after exposure to liquid supplied from a distributor 106 (liquefied gas feed and vaporized gas recovery not shown). Seawater is introduced into a supply line 110 via an inlet end 112 and supplied to the distributor 106. The incoming seawater is at a first temperature (T1) in the supply line 110 as it is supplied to the distributor 106. As the seawater passes through the open rack LNG vaporizer 102, it contacts the tubes 104 and heats the liquefied gas therein. The seawater undergoes cooling as a result, and the cooled seawater collects in a collection reservoir 120 below the open rack LNG vaporizer 102. The cooled seawater in the collection reservoir 120 is at a second temperature (T2) that is lower than the first temperature (T1).

[0013] At least a portion of the cooled seawater in the collection reservoir 120 is conveyed via the reservoir outlet line 130 to the heat exchanger 140. The heat exchanger 140 may include one or more cooling channels for receiving the cooled seawater to facilitate cooling the inlet air. Suitable heat exchanger types and cooling channel configurations therein are not believed to be particularly limited. Although shown in FIG. 1 as being coupled to a flow path 142 for cooling the inlet air, it should be understood that the concepts described herein are adaptable to perform alternative heat exchange processes. Thus, when performing alternative heat exchange processes, the flow path 142 for cooling the inlet air may not be present. The heat exchanger 140 is in thermal communication with a flow path 142. As shown in FIG. 1, the flow path 142 is integral with the heat exchanger 140, however, it is recognized that the flow path 142 may be external to the heat exchanger 140, or may be separate from the heat exchanger 140 altogether. FIGS. 3 and 4, described further below, illustrate types of systems and methods in which the heat exchanger 140 may be spaced from the flow path 142 while still maintaining thermal communication therewith. Inlet air passing through the flow path 142 undergoes heat exchange with cooling seawater before being delivered to a gas engine or gas turbine 150 via line 148. After heat exchange, the resulting cooled inlet air may facilitate more efficient operation of the gas engine or gas turbine 150.

[0014] After facilitating cooling of the inlet air in flow path 142, the heat-exchanged seawater exits heat exchanger 140 through heat exchanger outlet line 160 and subsequently discharged into the sea via outlet end 162. Upon exiting heat exchanger 140, the heat-exchanged seawater is at a third temperature (T3) that is higher than the second temperature (T2). The third temperature (T3) is often lower than the first temperature (T1), but in some cases may be higher. For example, when the ambient temperature is high, the third temperature (T3) may be higher than the first temperature (T1). If the temperature difference between the first temperature (T1) and the third temperature (T3) is small enough, preferably about 5° C. or less (e.g., the third temperature (T3) is up to about 5° C. lower than the first temperature (T1)), the heat-exchanged seawater in heat exchanger outlet line 160 may be discharged directly into the sea. In contrast, if the temperature difference for the heat exchanged seawater in the supply line 110 exceeds a certain threshold value compared to the temperature difference in the heat exchanged outlet line 160 (e.g., greater than about 5° C. or a similar value based on local environmental regulations, e.g., T3 is about 5° C. lower or even lower than T1), then measuring the actual seawater temperature difference at the specific location compared to the outlet end 162 can determine whether compliance with the temperature difference regulations (e.g., less than about 5° C.) is being met at the specific location. The heat dispersion at the outlet end 162 may determine the final temperature difference achieved between the ambient seawater in the supply line 110 and the seawater discharged from the heat exchanged outlet line 160, which is established based on the temperature measurement at the specific location. Site-specific conditions, discharge flow rate of the heat exchanged seawater, and local regulations, including definition of appropriate dispersion zones beyond the outlet end 162, may determine the final temperature difference that may exist at a given location. In other words, the temperature difference may exceed a particular value while the heat exchanged seawater is still in the heat exchanged outlet line 160, but nevertheless meet local temperature difference regulations after mixing with the ambient seawater has occurred in the water area. In a non-limiting example, the temperature difference at a particular location relative to the outlet end 162 may be about 5° C. or less compared to the temperature at the inlet end 112. That is, the seawater temperature at a particular location relative to the outlet end 162 may have a temperature T3' that may be higher, lower, or equal to T3, preferably T1-T3' is about 0° C. to about -5° C.If the seawater temperature at a particular location is excessively high, the circulation rate of the seawater through the system and method 100 can be slowed down to allow a greater temperature drop in the seawater to occur, thereby providing greater efficiency and power output of the gas turbine or gas engine. Conversely, if the seawater temperature at a particular location is excessively low (e.g., about 5° C. or more below the ambient seawater temperature) than the ambient seawater temperature, the circulation rate of the seawater through the system 100 can be increased to facilitate a smaller temperature drop in the open rack liquefied gas vaporizer 102 and a higher discharge rate from the outlet 162.

[0015] If T3 or T3' is not the desired value, the system and method 100 includes provisions for adjusting the seawater temperature in the heat exchanger outlet line 160. One way in which the temperature in the heat exchanger outlet line 160 may be controlled is by controlled release of excess chilled seawater from the collection reservoir 120 via the discharge line 170, thereby lowering the temperature of the heat exchanged seawater in the heat exchanger outlet line 160. In particular, the chilled seawater may be released from the collection reservoir 120 at a rate sufficient to prevent overflow of the collection reservoir 120. Furthermore, the rate of chilled seawater release from the collection reservoir 120 may be selected to maintain the temperature difference T1-T3 or T1-T3' within desired limits. Optionally, additional temperature control may be provided by supplying seawater from the supply line 110 to the heat exchanger outlet line 160 via a bypass line 180. For example, if the cooled seawater discharged from collection reservoir 120 reduces the temperature in heat exchanger outlet line 160 too much, the excess temperature reduction can be regulated by introducing uncooled seawater via bypass line 180. Additional temperature control within system and method 100 can be achieved by varying the overall flow rate of seawater therethrough.

[0016] In another example, when the ambient temperature is already low and cooling of the gas engine or gas turbine inlet air is not required at a particular time, the bypass line 180 may be utilized to bypass the open rack liquefied gas vaporizer 102. When the demand for vaporized gas is low (e.g., the demand for fuel gas is low), the liquefied gas vaporizer 102 may be bypassed by at least a portion of the seawater in the supply line 110. Furthermore, the amount of seawater supplied to the open rack liquefied gas vaporizer 102 may be controlled by the extent to which seawater is diverted via the bypass line 180 to the heat exchanger outlet line 160. In addition to controlling the volume of seawater supplied to the open rack liquefied gas vaporizer 102, the flow rate within the open rack liquefied gas vaporizer 102 may be controlled to similarly regulate the degree to which the seawater is cooled therein. Additional components and functionality may be present to allow further tailoring of seawater temperature and operational flexibility within the system and method 100. Optionally, cooled seawater from the collection reservoir 120 may be transferred to a cooled seawater holding tank 190 via line 192. The cooled seawater holding tank 190 can serve as a thermal reservoir as well as provide a source for achieving additional thermal control within the system and method 100. As shown, the cooled seawater holding tank 190 can distribute cooled seawater to either the reservoir outlet line 130, the heat exchanger 140, or the heat exchanger outlet line 160 via lines 135, 145, and 165, respectively. Another optional feature is a bypass line 148 that allows the cooled seawater to bypass the heat exchanger 140 by diverting the cooled seawater to the heat exchanger outlet line 160.

[0017] Additional system and method variations are described below with reference to Figures 2-4. The same reference characters are used in Figures 2-4 to annotate common elements having similar features to those described above with respect to Figure 1. Moreover, for the sake of brevity, elements in Figures 2-4 having similar operative characteristics to those described above with respect to Figure 1 will not be described again in detail. FIG. 2 is an illustration of a system and method for cooling the inlet air supplied to a gas engine or gas turbine using seawater cooled in a liquefied gas vaporizer divided into several sections. The system and method 200 shown in FIG. 2 is the same as that shown in FIG. 1, except that the open rack liquefied gas vaporizer 102 and the collection reservoir 120 are subdivided into 102a and 102b, and 120a and 120b, respectively. By subdividing the open rack liquefied gas vaporizer 102 and the collection reservoir 120, more extensive cooling can occur in one section of the open rack liquefied gas vaporizer 102 than in the other sections. Furthermore, by keeping the cooled seawater effluent from the open rack liquefied gas vaporizer 102 separate in the collection reservoir 120 (i.e., in sections 120a and 120b where no mixing occurs between the two sections), less flow control may be required when returning the cooled seawater to the heat exchanger outlet line 160 via the discharge line 170. 2, sections 102b and 120b can be partitioned to provide the desired degree of inlet air cooling so that the cooled seawater provided to heat exchanger 140 is available at the temperature and / or flow rate required to meet the cooling duty requirements. In this configuration, heat exchanger 140 provides a supply of cooled seawater for the cooling duty without relying on seawater collected in section 120a. The volume of seawater collected in section 120a can be determined by the vaporization (regasification) duty and other operational considerations. Provided that the temperature (T2') of the cooling seawater in section 120a is higher than the temperature (T2") of the cooling seawater in section 120b, the cooling seawater in section 120a can be returned to the heat exchanger outlet line 160 with less risk of thermal disruption in the configuration of the system and method 100 of FIG. 1. More extensive cooling of the cooling seawater in sections 102b and 120b can be achieved by providing a lower seawater flow rate to section 102b of the open rack LNG vaporizer 102 via the distributor 106, thereby allowing a smaller volume of seawater to undergo more extensive cooling upon contact with the tubes 104.2 as having different sizes, it will be appreciated that they may instead be substantially the same size. Furthermore, either of the sections 102a, 120a or 102b, 120b may be larger when partitioned differently.

[0018] In an alternative configuration to the system and method 100 of Figure 2, instead of subdivision, there may be two separate open rack LNG vaporizers 102 and two separate collection reservoirs, which may operate substantially similarly to that described above with reference to Figure 2, and for the sake of brevity, the operation will not be described in detail again. FIG. 3 is an illustration of a system and method for cooling inlet air supplied to a gas engine or gas turbine with a secondary heat transfer fluid cooled with seawater cooled in a liquefied gas vaporizer. The system and method 300 shown in FIG. 3 is similar to that shown in FIG. 1, except that the heat exchanger 140 is in indirect thermal communication with the flow path 142 through the secondary heat transfer fluid 310, which is in fluid communication with the secondary heat exchanger 320. In the system and method 300, the secondary heat transfer fluid 310 is first directly cooled with the cooling seawater entering the heat exchanger 140 via the reservoir outlet line 130, so that the secondary heat transfer fluid 310 can facilitate cooling of the inlet air in the flow path 142, which is in direct thermal communication with the secondary heat exchanger 320. The use of the secondary heat transfer fluid 310 reduces thermodynamic efficiency, but may realize the benefit of a less corrosive environment in the flow path 142 and the secondary heat exchanger 310. In particular, by avoiding contact of flowpath 142 with seawater, corrosion and / or fouling within flowpath 142 may be reduced or avoided. Again, it will be appreciated that the concepts described herein are also applicable to the implementation of alternative heat exchange processes that do not involve thermal control of the flowpath and thus do not require flowpath 142 to be present and in direct thermal communication with secondary heat exchanger 310.

[0019] Figure 4 is an illustration of a system and method for cooling inlet air supplied to a gas engine or gas turbine using a secondary heat transfer fluid cooled by seawater cooled in a liquefied gas vaporizer divided into several sections. The system and method 400 shown in Figure 4 is substantially similar to that shown in Figure 3, except that the open rack liquefied gas vaporizer 102 and the collection reservoir 120 are subdivided into sections 102a and 102b, and 120a and 120b, respectively, as shown in the system and method 200 of Figure 2. In conjunction with the system and method 400 of Figure 4, similar benefits may be realized as described above with reference to Figures 2 and 3. Thus, a system for cooling an inlet air stream with seawater may include a liquefied gas vaporizer, for example an open rack liquefied gas vaporizer, a seawater inlet connected to a supply line configured to distribute seawater to the liquefied gas vaporizer, a collection reservoir below the liquefied gas vaporizer configured to collect cooled seawater passing through the liquefied gas vaporizer, a heat exchanger in fluid communication with the collection reservoir via a reservoir outlet line, and a heat exchanger outlet line connected to a seawater outlet configured to discharge the seawater into a marine body. Pumps, valves, and similar equipment may be utilized to achieve certain operating and control objectives.

[0020] In certain system configurations, the system may be configured to provide cooling of inlet air supplied to the gas engine or gas turbine, i.e., the heat exchanger may be in direct or indirect thermal communication with a flowpath for the air supplied to the gas engine or gas turbine. The disclosed system may further incorporate a gas engine or gas turbine configured to receive the outlet flow of cooling air provided from the flow path. Suitable examples of gas engines and gas turbines will be familiar to those skilled in the art. Exemplary systems include combined cycle power plants using industrial or aeroderivative gas turbines, simple cycle power plants using industrial or aeroderivative gas turbines, and reciprocating piston engines using natural gas or other suitable gaseous fuels, such as natural gas mixtures. Industrial processes requiring mechanical power and / or combining heat generation and power generation processes may benefit from the disclosure herein. The system may include configurations in which the gas engine or gas turbine is located on land or on a floating platform. In some system configurations, the gas engine or gas turbine may be supplied with vaporized fuel gas (e.g., natural gas, hydrogen, or a combination thereof) from a liquefied gas vaporizer. In non-limiting examples, the system of the present disclosure incorporating both a liquefied gas vaporizer and a gas engine or gas turbine may be present in a coupled regasification plant located near or integrated with an offshore power plant, or a floating regasification unit may be integrated with a floating power generation unit.

[0021] The disclosed system may include a discharge line extending from the collection reservoir in fluid communication with the heat exchanger outlet line. In some cases, a bypass line may extend from the supply line in fluid communication with the heat exchanger outlet line, resulting in some of the seawater in the supply line not being supplied to the liquefied gas vaporizer. Introducing cooled seawater from the discharge line and / or seawater from the bypass line into the heat exchanger outlet line may adjust the temperature of the seawater in the heat exchanger outlet line before the seawater is discharged into the ocean. In some cases, some of the incoming seawater may pass through the bypass line, thereby avoiding the liquefied gas vaporizer and the entire flow path (e.g., when the ambient temperature is low and air cooling requirements are minimal, in which case a reduced volume of seawater supplied to the liquefied gas vaporizer may assist with the vaporization duty). Preferably, the temperature difference between the seawater inlet and the specific location relative to the seawater outlet may be about 5° C. or less, and more preferably the specific location is at a temperature that is about 5° C. or less relative to the seawater inlet. Prior to dispersion across the seawater outlet, the temperature difference between the supply line and the discharge line can be about 15°C or less, or about 10°C or less, or about 5°C or less, for example, from about 1°C to about 10°C, or from about 5°C to about 12°C, or from about 3°C ​​to about 8°C, or from about 7°C to about 13°C, or from about 5°C to about 10°C. In one example, the seawater may be discharged into the ocean body at a location that allows for optimal mixing and cooling within the thermal plume. The discharged seawater may be within about 3°C ​​of the surrounding water at the edge of the mixing zone or within 100 meters of the seawater outlet. Further details may be provided in the International Finance Corporation (IFC) guidelines. Requirements specific to particular regions may be governed by local regulations.

[0022] The cooling seawater supplied to the heat exchanger may be in direct thermal communication with the flow passage (if present) or indirectly with the flow passage (if present) through a secondary heat transfer fluid in thermal communication with a secondary heat exchanger, which in turn may be in direct thermal communication with the flow passage used to cool the inlet air. Optionally, the liquefied gas vaporizer and the collection reservoir may be divided into a first compartment and a second compartment, respectively. The first and second compartments of the collection reservoir may maintain the cooled seawater separately in each compartment so that they do not mix with each other. In such an embodiment, the supply line may be configured to distribute a first portion of the seawater to the first compartment of the liquefied gas vaporizer and distribute a second portion of the seawater to the second compartment of the liquefied gas vaporizer. Preferably, the distribution of seawater to the first and second compartments of the liquefied gas vaporizer occurs at different rates, such that the cooled seawater in the corresponding first and second compartments of the collection reservoir may have different temperatures. Furthermore, the flow rate of seawater to the first and second compartments may be controlled to achieve active control of the temperature in the first and second compartments of the collection reservoir. The cooled seawater collected in the first compartment of the collection reservoir can be obtained from a corresponding first compartment of the liquefied gas vaporizer, and the cooled seawater collected in the second compartment of the collection reservoir can be obtained from a corresponding second compartment of the liquefied gas vaporizer. The discharge line may extend from one compartment of the collection reservoir. In a non-limiting example, by providing different amounts of seawater per unit contact area in each compartment of the liquefied gas vaporizer, the cooled seawater exiting the different compartments of the liquefied gas vaporizer can achieve different temperatures. A higher ratio of seawater per unit contact area and / or per unit volume of liquefied gas (e.g., LNG and / or hydrogen) can result in a smaller temperature drop of the cooled seawater, and a lower ratio of seawater per unit contact area can result in a larger temperature drop of the cooled seawater. Different ratios of seawater per unit contact area or per unit volume can be achieved by introducing seawater at different flow rates into each compartment of the liquefied gas vaporizer.

[0023] When the liquefied gas vaporizer and collection reservoir are divided into first and second compartments, one of the first compartment or the second compartment may be configured to supply cooled seawater to the heat exchanger. A discharge line may extend from the other of the first compartment or the second compartment of the collection reservoir to establish fluid communication with the heat exchanger outlet line. Preferably, the compartment with cooled seawater at a lower temperature (T2") of the collection reservoir may be provided in the heat exchanger, e.g. for cooling the inlet air, and the compartment with cooled seawater at a higher temperature of the collection reservoir may be provided in the heat exchanger outlet line to facilitate thermal control therein before discharge of the seawater. As an alternative to a liquefied gas vaporizer and collection reservoir divided into several compartments, two liquefied gas vaporizers and collection reservoirs can be operated in parallel in a manner substantially similar to that described above, with a discharge line extending from one collection reservoir and a reservoir outlet line extending from the other collection reservoir. In either embodiment, the supply line may be capable of dispensing seawater to the liquefied gas vaporizer at a variable rate. Variable rate dispensing of seawater may be accomplished by a pump capable of transporting liquid at a variable rate. Suitable examples of variable speed pumps will be familiar to those skilled in the art. Variations in flow rate may regulate the overall flow to the liquefied gas vaporizer and / or individual sections thereof or separate liquefied gas vaporizers, which may provide additional thermal control possibilities to the present disclosure. Optionally, a bypass line may extend from the reservoir outlet line to the heat exchanger outlet line. The bypass line may divert the cooled seawater when there is less need for air cooling or other heat exchange. Using the bypass line in this manner, the second temperature (T2) may be maintained at a substantially constant low value in the reservoir outlet line, and cooled seawater may be supplied to the heat exchanger as needed to achieve a target temperature therein. Further optionally, a cooling seawater holding tank may be in fluid communication with the collection reservoir. The cooling seawater holding tank may provide additional operational flexibility as well as serve as a thermal reservoir for other related processes. In the systems and methods of the present disclosure, cooling seawater may be provided from the cooling seawater holding tank to the heat exchanger, the heat exchanger outlet line, or any combination thereof.

[0024] The disclosed method may include the steps of: supplying a liquefied gas stream to a liquefied gas vaporizer; introducing seawater via a seawater inlet into a supply line; distributing the seawater stream from the supply line to the liquefied gas vaporizer, thereby reducing the temperature of the seawater from a first temperature to a second temperature to form cooled seawater; collecting the cooled seawater at approximately the second temperature in a collection reservoir below the liquefied gas vaporizer; supplying the cooled seawater stream from the collection reservoir to a heat exchanger, where the seawater is heated from the second temperature to a third temperature to form heat-exchanged seawater; and removing the heat-exchanged seawater stream from the heat exchanger via a heat exchanger outlet line. Optionally, as further described herein, the heat exchanger may be in direct or indirect fluid communication with a flow path for air supplied to the gas engine or gas turbine. As such, the method may further include supplying an outlet flow of cooling air from the flow path to the gas engine or gas turbine. The flow rate of the seawater stream delivered to the liquefied gas vaporizer may vary the speed, power, or efficiency of the gas engine or gas turbine, for example, depending on specific operating requirements. The liquefied gas may be liquefied natural gas or liquefied hydrogen, and the liquefied gas vaporizer may be a liquefied natural gas vaporizer or a liquefied hydrogen vaporizer. The vaporized natural gas, vaporized hydrogen, or a combination thereof may be supplied to a gas engine or gas turbine that receives inlet air that has been thermally controlled according to the disclosure herein.

[0025] The method may further comprise discharging the heat exchanged seawater into the body of water via a seawater outlet. Preferably, a temperature difference between the seawater inlet and a particular location relative to the seawater outlet is less than 5°C. One or more flows of seawater may be introduced into the heat-exchanged seawater at the third temperature prior to discharge into the marine body. In one example, a flow of cooled seawater from a collection reservoir, a reservoir outlet line, or a cooled seawater holding tank may be introduced into the heat exchanger outlet line prior to discharge of the heat-exchanged seawater into the marine body. In another example, a flow of seawater at approximately the first temperature may be introduced into the heat exchanger outlet line from a supply line prior to discharge of the heat-exchanged seawater into the marine body. The introduction of seawater or cooled seawater from any of these locations may occur, including in combination with each other. Thus, the introduction of seawater at the first temperature and / or cooled seawater at the second temperature into the heat exchanger outlet line may provide the thermal control necessary to meet certain discharge requirements. The systems and methods of the present disclosure may result in more efficient operation of the gas engine or gas turbine than would otherwise be possible by facilitating deeper cooling of the seawater in the liquefied gas vaporizer. In another example, the present disclosure may also control the speed of the gas engine or gas turbine by adjusting the temperature of the inlet air supplied to the gas engine or gas turbine. For example, it may be desirable to adjust the power of the gas engine or gas turbine. Thus, the methods of the present disclosure may include adjusting the flow rate of the flow of seawater delivered to the liquefied gas vaporizer to vary the speed of the gas engine or gas turbine.

[0026] Embodiments disclosed herein include the following: A. Inlet Air Cooling System. The system includes a liquefied gas vaporizer, a seawater inlet connected to a supply line configured to distribute seawater to the liquefied gas vaporizer, a collection reservoir below the liquefied gas vaporizer configured to collect cooled seawater passing through the liquefied gas vaporizer, a heat exchanger in fluid communication with the collection reservoir via a reservoir outlet line, and a heat exchanger outlet line connected to a seawater outlet configured to discharge the heat exchanged seawater into a marine body. B. A method for cooling inlet air, the method including the steps of supplying a liquefied gas stream to a liquefied gas vaporizer, introducing seawater via a seawater inlet into a supply line, distributing the seawater stream from the supply line to the liquefied gas vaporizer thereby reducing a temperature of the seawater from a first temperature to a second temperature to form cooled seawater, collecting the cooled seawater at approximately the second temperature in a collection reservoir below the liquefied gas vaporizer, supplying the cooled seawater stream from the collection reservoir to a heat exchanger where the seawater is heated from the second temperature to a third temperature to form heat exchanged seawater, and removing the heat exchanged seawater stream from the heat exchanger via a heat exchanger outlet line.

[0027] Embodiments A and B may have one or more of the following elements in any combination: Element 1: The liquefied gas vaporizer is a liquefied natural gas vaporizer or a liquefied hydrogen vaporizer. Element 1A: The liquefied gas is liquefied natural gas or liquefied hydrogen, and the liquefied gas vaporizer is a liquefied natural gas vaporizer or a liquefied hydrogen vaporizer. Element 2: The heat exchanger is in direct or indirect thermal communication with a flow path for the air supplying the gas engine or gas turbine. Element 3: The heat exchanger is in direct thermal communication with the flow path. Element 4: The heat exchanger is in indirect thermal communication with the flow path via a secondary heat transfer fluid that is in fluid communication with the secondary heat exchanger, which is in direct thermal communication with the flow path. Item 5: The system further includes a gas engine or gas turbine configured to receive a supply of cooling air from the flow path. Element 5A: The method further includes the step of supplying an outlet flow of cooling air from the flow passage to a gas engine or gas turbine. Element 6: The system further includes a drain line extending from the collection reservoir to the heat exchanger outlet line. Element 7: The system further includes a bypass line extending from the reservoir outlet line to the heat exchanger outlet line.

[0028] Element 8: The liquefied gas vaporizer and the collection reservoir are divided into a first compartment and a second compartment, respectively, and one of the first compartment or the second compartment of the collection reservoir is configured to supply cooled seawater to the heat exchanger via the reservoir outlet line. Element 8A: The liquefied gas vaporizer and the collection reservoir are divided into a first compartment and a second compartment, respectively, and one of the first compartment or the second compartment of the collection reservoir is configured to supply cooled seawater to the heat exchanger. Element 9: The system further includes a drain line extending from one of the first compartment or the second compartment of the collection reservoir to the heat exchanger outlet line. Element 10: The supply line is configured to distribute a first portion of the seawater to a first compartment of the liquefied gas vaporizer and to distribute a second portion of the seawater to a second compartment of the liquefied gas vaporizer. Element 10A: Via a supply line, a first portion of seawater is distributed to a first compartment of a liquefied gas vaporizer, and a second portion of seawater is distributed to a second compartment of the liquefied gas vaporizer. Element 11: The supply line is configured to deliver the first portion of the seawater and the second portion of the seawater to the liquefied gas vaporizer at different rates. Element 11A: A first portion of seawater and a second portion of seawater are delivered to a liquefied gas vaporizer at different rates.

[0029] Element 12: The system further includes a bypass line extending from the supply line to the heat exchanger outlet line. Element 12A: The method further includes the step of directing a flow of seawater from the supply line to the heat exchanger outlet line prior to discharging the heat exchanged seawater into the body of water. Element 13: The system further includes a cooled seawater holding tank in fluid communication with the collection reservoir. Element 13A: The method further includes transferring cooled seawater from the collection reservoir to a cooled seawater holding tank, and supplying cooled seawater from the cooled seawater holding tank to a heat exchanger or a heat exchanger outlet line. Element 14: The cooled seawater holding tank is in fluid communication with the heat exchanger or the heat exchanger outlet line. Element 15: The supply line is capable of distributing seawater at a variable rate to the liquefied gas vaporizer. Item 16: The liquefied gas vaporizer includes an open rack vaporizer. Element 17: The method further includes adjusting the flow rate of the seawater stream delivered to the liquefied gas vaporizer to vary the speed, power or efficiency of the gas engine or gas turbine. Element 18: The method further includes discharging the heat exchanged seawater into the marine body via a seawater outlet. Element 19: The temperature difference of the seawater between the seawater inlet and a specific location relative to the seawater outlet is about 5° C. or less. Element 20: The method further includes the step of introducing a flow of cooled seawater into the heat exchanger outlet line prior to discharging the heat exchanged seawater into the marine body, the flow of cooled seawater being introduced from a collection reservoir or a reservoir outlet line extending from the collection reservoir to the heat exchanger. Element 21: Prior to discharging the heat exchanged seawater into the ocean body, a flow of cooled seawater is introduced from a collection reservoir into the heat exchanger outlet line, the cooled seawater being introduced from one of the first compartment or the second compartment of the collection reservoir.

[0030] As non-limiting examples, typical combinations applicable to A and B include, but are not limited to, 1 or 1A, and 2, 3 or 4; 1 or 1A, and 5 or 5A; 1 or 1A, and 2, 3 or 4, and 5 or 5A; 1 or 1A, and 6 or 6A; 1 or 1A, and 8 or 8A; 1 or 1A, and 13; 1, 13 and 14; 1 or 1A, and 15; 1 or 1A, and 16; 1A and 17; 1A and 18; 1A and 19; 3 or 4, and 5 or 5A; 3 or 4, and 8 or 8A; 3 or 4, and 8 or 8A, and 9; 3 or 4, 9, and 10 or 10A; 3 or 4, 8 or 8A, and 11 or 11A; 3 or 4, and 15 or 17; 3 or 4, and 16; 3 or 4, and 18; 3 or 4, and 19; 3 or 4, and 20; 3 or 4, and 21; 5 or 5A in combination with any one or more of 1, 1A, 2, 3, 4, 6, 7, 8, 8A, 9, 10, 10A, 11, 11A, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 21; 8 or 8A, and 9; 8 or 8A, and 10 or 10A; 8 or 8A, and 11; 8 or 8A, 9, and 11; 8 or 8A, and 13 or 13A; 8 or 8A, and 16; 8A and 17; 8A and 18; 8A and 19; 16 and 17; 16 and 18; 16 and 19; 16 and 20; and 16 and 21.

[0031] All documents described herein, including any priority documents and / or test procedures, are incorporated herein for all jurisdictions where incorporation by reference is permitted, to the extent that they do not contradict this text. As is apparent from the general description and specific embodiments above, the form of the disclosure has been illustrated and described, but various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, the disclosure is not intended to be limited thereby. For example, the compositions described herein may be free of any component or composition not expressly listed or disclosed herein. Any method may be devoid of any step not listed or disclosed herein. Similarly, the term "comprising" is considered synonymous with the term "including." Whenever the transitional phrase "comprising" precedes a method, composition, element, or group of elements, we shall understand that we also contemplate the same composition or group of elements with the transitional phrase "consisting essentially of," "consisting of," "selected from the group of consisting of," or "is" preceding the composition, element, or list of elements, and vice versa.

[0032] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, e.g., molecular weight, reaction conditions, and the like, used in the specification and appended claims should be understood to be modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed at least in light of the number of reported significant digits and by applying ordinary rounding techniques. Whenever a numerical range with a lower and upper limit is disclosed, each and every numerical value falling within that range and each and every encompassing range is specifically disclosed. In particular, any range of values ​​disclosed herein (in the form "from about a to about b" or, equivalently, "from approximately a to b" or, equivalently, "from approximately ab") should be understood to represent each and every number and range encompassed within the broader range of values. Additionally, the terms in the claims have their plain and ordinary meaning unless expressly and unambiguously defined otherwise by the patent owner. Additionally, the indefinite article "a" or "an" as used in the claims is defined herein to mean one or more of the elements it introduces.

[0033] One or more exemplary embodiments are presented herein. For the sake of clarity, not all features of a physical implementation are described or shown in this application. There is a common understanding that in developing a physical embodiment of the present disclosure, many implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related and other constraints that vary from implementation to implementation and from time to time. Although the developer's efforts may be time-consuming, such efforts would nevertheless be routine for one of ordinary skill in the art and having the benefit of this disclosure to undertake. Thus, the present disclosure is well adapted to achieve the ends and advantages mentioned as well as those inherent therein. The particular embodiments disclosed above are merely illustrative, as the disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art and having the benefit of the teachings herein. Moreover, no limitations are intended to the details of construction or design shown herein, other than as set forth in the following claims. Thus, it is apparent that the particular exemplary embodiments disclosed above may be altered, combined or modified, and all such variations are considered within the scope and spirit of the present disclosure. Illustratively, the embodiments disclosed herein suitably may be practiced in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein.

Claims

1. A liquefied gas vaporizer; a seawater inlet connected to a supply line configured to deliver seawater to the liquefied gas vaporizer; a collection reservoir below the liquefied gas vaporizer configured to collect cooled seawater passing through the liquefied gas vaporizer; a heat exchanger in fluid communication with the collection reservoir via a reservoir outlet line; a heat exchanger outlet line connected to a seawater outlet configured to discharge the heat-exchanged seawater into a marine environment; Including, the system.

2. 2. The system of claim 1, wherein the liquefied gas vaporizer is a liquefied natural gas vaporizer or a liquefied hydrogen vaporizer.

3. the heat exchanger is in direct or indirect thermal communication with an air flow path supplying a gas engine or gas turbine; and 2. The system of claim 1, wherein the secondary heat exchanger is in direct thermal communication with the flow path when the heat exchanger is in indirect thermal communication with the flow path via a secondary heat transfer fluid that is in fluid communication with the secondary heat exchanger.

4. The system of claim 1, further comprising one of the following (i) to (iii): (i) A gas engine or gas turbine configured to receive a supply of cooling air from the flow path. (ii) a discharge line extending from the collection reservoir to the heat exchanger outlet line; (iii) a bypass line extending from the reservoir outlet line to the heat exchanger outlet line;

5. the liquefied gas vaporizer and the collection reservoir are each divided into a first compartment and a second compartment; one of the first compartment or the second compartment of the collection reservoir is configured to supply cooled seawater to the heat exchanger via the reservoir outlet line; The system of claim 1.

6. 6. The system of claim 5, further comprising a drain line extending from one of the first compartment or the second compartment of the collection reservoir to the heat exchanger outlet line.

7. 6. The system of claim 5, wherein the supply line is configured to distribute a first portion of seawater to a first compartment of the liquefied gas vaporizer and a second portion of seawater to a second compartment of the liquefied gas vaporizer.

8. 8. The system of claim 7, wherein the supply line is configured to deliver the first portion of seawater and the second portion of seawater to the liquefied gas vaporizer at different rates.

9. The system of claim 1, further comprising one or both of the following (iv) and (v): (iv) a bypass line extending from the supply line to the heat exchanger outlet line; (v) a cooled seawater holding tank in fluid communication with the collection reservoir;

10. A method of cooling seawater to facilitate heat exchange, using a system as described in any one of claims 1 to 9, wherein the discharging seawater is maintained within a desired temperature differential.

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