KR20110007667A - Cargo handling method for high pressure liquid cargo using pumps and immiscible piston liquid and cargo handling system thereof - Google Patents

Abstract

PURPOSE: A method and a system for loading and unloading high-pressure liquid cargo are provided to reduce the loading/unloading time of cargo since most cargo is first loaded/unloaded using a pump and remaining high-pressure gas cargo is pushed/pulled using piston liquid. CONSTITUTION: A system for loading and unloading high-pressure liquid cargo using pumps and immiscible liquid comprises a cargo container(100), a cargo transfer pump(200), a piston liquid receiver(300) and a supplementary gas receiver(400). The cargo container holds high-pressure liquid cargo and receives cargo from the liquid cargo storage(700) of a cargo base or sends it to the storage. The cargo transfer pump sends the liquid cargo from the cargo container to the liquid cargo storage. The piston liquid receiver holds the piston liquid, which pushes or is pushed from the cargo in loading or unloading the cargo, and supplies the piston liquid to the cargo container or receives it.

Description

Cargo Handling Method for High Pressure Liquid Cargo Using Pumps and Immiscible Piston Liquid and Cargo Handling System Thereof}

The present invention relates to a method and equipment for cargo loading and unloading using a pump and unmixed piston liquid for transporting high pressure liquid cargo.

Hydrocarbons such as LPG (Liquefied Petroleum Gas) are currently transported by ship, and in the case of carbon dioxide, transportation by ship is expected to increase in the future for sequestration of greenhouse gases. LPG or carbon dioxide is in a gaseous state at room temperature under atmospheric pressure, and when transported in a gaseous state as it is, economical efficiency is low. Therefore, in order to transport these gases to the vessel, the temperature must be lowered or the pressure increased to make the liquid phase. Until now, the method of lowering the temperature to liquefy has been widely used.

An example of an LPG carrier that carries such low temperature liquid cargo is shown in FIG. 1. As shown in FIG. 1, the low temperature liquid cargo carrier carries and transports the low temperature liquid cargo in a cargo tank (a portion indicated by a bold circumference and a hatched line in FIG. 1) that occupies almost the entire volume of the carrier. The cold liquid cargo thus conveyed is generally unloaded by pumping.

On the other hand, there is an example of a high-pressure cargo, such as CNG (Compressed Natural Gas), the CNG is in the gas state when transporting. Figure 2 shows the actual shape of the various CNG carriers, as shown in Figure 2 (A) CNG is to be accommodated in a special container made to withstand high pressure. Figure 3 is a simplified illustration of the unloading method used in the conventional CNG carrier. When unloading a conventional CNG carrier, as shown in FIG. 3, one side of the CNG vessel (as shown in FIG. 2A) is opened, and the other side of the CNG vessel is not mixed with CNG, such as ethylene glycol. The liquid which does not enter is pushed in and CNG is pushed out by ethylene glycol so that unloading is performed. As described above, since the CNG is in a gaseous state, when it is pushed out using a liquid such as ethylene glycol, almost no mixing occurs due to the difference in density. This principle can of course also be applied at the time of shipment.

By the way, in the prior art, LPG was transported in a low temperature atmospheric pressure state, but a need arises to transport it at room temperature and high pressure. Accordingly, there has been a problem in that the conventional method of using a pump at the time of loading or unloading liquid cargo under atmospheric pressure cannot be used as it is. Accordingly, there was a problem in that loading and unloading by using a pump but having to add a pressure regulator. In addition, in the case of using the pump, there is a possibility that the remaining cargo remains inside the container, and the purity of the newly shipped cargo may be lowered when the next shipment of other cargoes is carried out. There is a problem that requires a separate step. That is, the equipment for loading and unloading the high pressure liquid cargo is not sufficiently optimized at present.

In addition, using the principle of loading or unloading the CNG using the same method of pushing out with other liquids, there are the following problems. First, since CNG is a gas, it hardly mixes with each other due to density difference in the process of pushing out using another liquid. However, in the case of a liquid such as high pressure LPG, even if it is pushed into a liquid (for example, water) having a property that does not mix with each other, they are mixed with each other by physical effects such as high flow rate. Of course, the large mixed parts can be easily separated by the nature (density difference, etc.) that the liquids do not mix with each other, but it takes a very long time to separate when droplets (emulsions) occur in the liquid due to the high flow rate There is. In addition, if the separation time is reduced, there is a problem that the purity of the cargo sent out is lowered. Therefore, if you want to apply the principle of pushing the gas into the liquid (that is, when loading and unloading conventional CNG) and pushing the liquid into the liquid (for example, LPG in a high pressure liquid when loading and unloading with water) It is obvious that the above problems must be solved.

Korean Patent Publication No. 2009-0036361 (“LNG carrier having the pressure control device and the said pressure control device at the time of unloading LNG carrier”, hereinafter prior art 1), LNG is partially evaporated in a LNG (Liquified Natural Gas) storage tank As the internal pressure increases, there is disclosed a technology for liquid cargo unloading equipment including a pressure regulating device that controls the supply pressure of the evaporated gas when unloading from the LNG storage tank to the LNG receiving base. However, even in the case of the prior art 1, the actual loading and unloading itself is made by a pump, and in the case of LNG, even though the internal pressure increases due to the low temperature liquid cargo, the evaporation gas does not significantly deviate from the atmospheric pressure. It is only. However, in the case of the high-pressure liquid cargo to be dealt with in the present invention is a very high pressure of several times to several tens of atmospheric pressure bar, there is a problem such as safety, durability to apply the prior art 1 as it is.

Conventionally, in the case of the loading and unloading equipment of the CNG, the principle of pushing out using the liquid is used as described above, but the application of the same to the high pressure liquid cargo has the problem that the separation time increases and the purity of the cargo decreases because the liquids are mixed. . In addition, as in the technique disclosed in Korean Patent Publication No. 2008-0031263 (“Method for Transporting and Storing Gas in Liquid Medium”, hereinafter, Prior Art 2), CNG is dissolved in a liquid solvent and transported. There is also a method of separating the solvent from the solvent by evaporation and returning it back to the gas state to unload it. However, this method requires many steps such as dissolving CNG in a solvent, dehydrating CNG, separating the CNG from the solvent again, and unloading the separated CNG. There is a problem.

In order to solve these shortcomings, research and development have been carried out to improve the driving fluid and related equipment to load and unload high-pressure liquid cargo. Figure 4 is a way of loading or unloading high-pressure liquid cargo using the liquid (application number 10-2009-0040141 cargo loading and unloading equipment using a non-mixed piston fluid and driving gas for the high-pressure liquid cargo carrier). This design installed a separator plate and a liquid separator in the storage container for the smooth separation of the driving liquid and the liquid cargo. However, there are disadvantages in that the operation is complicated and a large liquid separator is required to separate the driving liquid and the cargo liquid.

5 is a design of a high pressure liquid cargo ship and unloading using a driving gas (source number 10-2009-0035465 cargo handling apparatus and method for transporting a liquefied gas cargo). In this scheme, since the driving fluid is a gas, separation from the cargo is easy, but a large amount of energy is consumed to compress the driving gas.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to push the high-pressure liquid cargo into the container by using a piston liquid that is not mixed with the pump and the cargo is shipped or Most cargo is loaded and unloaded by pump in liquid state, and the remaining high-pressure gas cargo is moved by piston liquid and re-liquefied by compressor and cooler. By loading and unloading, a method for loading and unloading cargo using a pump and an unmixed piston liquid for transporting a high pressure liquid cargo, which shortens the time required for loading and unloading the cargo and increases energy purity while reducing energy consumption. And providing the equipment.

Freight loading and unloading equipment for transporting high pressure liquid cargo using the pump and the non-mixed driving liquid of the present invention is a cargo receiving container for receiving or discharging cargo from the liquid cargo storage of the cargo receiving base, the high-pressure liquid cargo; A cargo transfer pump for discharging the liquid cargo in the cargo container to the liquid cargo reservoir; A piston liquid container receiving a piston liquid which pushes the cargo or is pushed out of the cargo during the loading or unloading of the cargo and supplies or recovers the piston liquid to the cargo receiving container; It comprises a; a supplement gas receiving unit for supplying a supplement gas to the cargo receiving container.

On the other hand, it is preferable to include a three-phase separator connected to the cargo container and the cargo transfer pump, respectively, and separates the cargo transported from the cargo container into three phases.

Also included is a reliquefaction section for reliquefaction of gaseous cargo delivered from the cargo containment vessel and the reliquefaction section includes a compressed cargo separator for separating and transferring the non-reliquefied gaseous cargo to a non-condensable gas reservoir.

On the other hand, the replenishment gas receiving unit is connected to the liquid cargo reservoir is preferably supplied with a supplementary gas vapor phase cargo discharged from the liquid cargo reservoir evaporated.

Unloading method of high pressure liquid cargo using the pump and the non-mixed driving liquid according to the present invention is a liquid phase of the liquid cargo transported from the cargo container containing the high pressure liquid cargo to the liquid cargo storage of the cargo receiving base through the cargo transfer pump Cargo unloading step; A vapor phase cargo unloading step of liquefying vapor phase cargo remaining in the cargo receiving container after the liquid phase cargo loading step and discharging the liquid phase cargo storage; And a replenishment gas supplying step of filling the cargo accommodating container with replenishing gas.

On the other hand, the gas phase cargo unloading step is to supply a piston liquid in the cargo container, the piston liquid supply step of pushing the gaseous cargo remaining in the cargo container; And a liquefaction step of liquefying gaseous cargo discharged from the cargo container by the piston liquid. Including,

The replenishment gas supplying step supplies the replenishment gas while simultaneously discharging the piston liquid from the cargo receiving container after the vapor phase cargo unloading step.

According to the present invention, when loading or unloading a high-pressure liquid cargo, most of the cargo is first loaded and unloaded by using a pump, and the remaining high-pressure gas cargo is pushed or pushed by using a piston liquid This shortens the time it takes to load and unload cargo and reduces energy consumption.

In addition, it is possible to increase the purity of the high pressure liquid cargo by using the unmixed piston liquid to move the high pressure gas cargo and reliquefy it.

Hereinafter, with reference to the accompanying drawings, a cargo loading and unloading method and equipment using a pump and a non-mixed piston liquid for transporting a high pressure liquid cargo according to the present invention having the configuration as described above will be described in detail.

Figure 6 is an embodiment of the loading and unloading equipment of the present invention, Figures 7 and 8 are a flow chart showing the fluid flow of loading and unloading by the loading and unloading method of the present invention, respectively.

The embodiment of the unloading equipment of Figure 6 shows a case where there are three containers for storing the cargo, the application principle is not changed even if the number of cargo containers is increased. First, the loading and unloading equipment of the present invention is a cargo receiving container 101, 102, 103, three-phase separator 500, cargo transfer pump 200, gas cargo compressor 610, as shown in FIG. Compressed cargo cooler 620, compressed cargo separator 630, compressed cargo evaporator 710 and associated piping and valves.

The cargo receiving containers 101, 102, 103 accommodate high pressure liquid cargo and are connected to the liquid cargo reservoir 700 of the external cargo receiving base through the cargo main pipe 120 to the cargo valves 111, 112, and 113. By receiving the cargo into it. Cargo unloaded from the cargo receiving containers (101, 102, 103) after being moved to the three-phase separator 500 through the liquid recovery valves (131, 132, 133) and the liquid recovery main pipe 140, and then subjected to appropriate separation Outflow to the external liquid cargo reservoir 700 through the cargo transfer pump 200.

Piston liquid stored in the piston liquid receiving portion (301, 302, 303) is connected to the cargo receiving container (101, 102, 103) through the liquid supply main pipe 320 to the cargo receiving container by the liquid supply valve (311, 312, 313) (101, 102, 103) is supplied to the piston liquid receiving portion (301, 302, 303) from the cargo receiving vessel (101, 102, 103) again through the liquid recovery pipe and the liquid recovery valve (131, 132, 133).

  The make-up gas is supplied from the make-up gas reservoir and supplied to the cargo receiving containers 101, 102, 103 through the make-up gas main pipe 420, and the supply is regulated through the make-up gas valves 411, 412, 413. If the replenishment gas is insufficient or requires high purity, a portion of the cargo to be unloaded is supplied from the liquid cargo reservoir 700 and evaporated using the cargo evaporator 710 to be used instead of the replenishment gas.

The gaseous cargo remaining in the cargo receiving containers 101, 102, 103 passes through the cargo valves 111, 112, 113, and then through the cargo main pipe 120, after the droplets are separated in the three-phase separator 500. After the pressure is increased through the cargo compressor 610, it is liquefied through the reliquefaction unit 600 that is liquefied through the compressed cargo cooler (620). The reliquefied gaseous cargo is separated from the non-condensable gas in the compressed cargo separator 630 and then merged with the liquid cargo that is supplied to the three-phase separator 500 through the compressed cargo separator level control valve 640.

The cargo loading and unloading method according to the present invention for loading and unloading cargo by the cargo loading and unloading equipment as described above will be described with reference to FIG. 7. The line exiting and entering the lower portion of the cargo accommodating container 101 is a path of movement of the piston liquid.

By the cargo loading and unloading equipment of the present invention thus configured, it is loaded according to the following steps.

For the first time, the liquid supply valves 311, 312, 313 are opened so that the piston liquid flows from the piston liquid container 302 to fill the first cargo container 101. The high pressure liquid cargo is then supplied from the liquid cargo reservoir 702 to fill the cargo containment vessel 101 while pushing the piston liquid inside the first cargo containment vessel 101. The pushed out piston liquid travels through the liquid return valve 131 to the next cargo container 102.

When the cargo loading for the first cargo container 101 is finished, the loading for the second cargo container 102 is also performed in the same manner.

The piston liquid discharged from the cargo container 101, 102, 103 is recovered to the piston liquid container 301 through the liquid recovery valves 131, 132, 133. At this time, since the last recovered piston liquid may contain a small amount of cargo, it is separated from the cargo through the three-phase separator 500, and the separated cargo is the liquid cargo reservoir 702, and the separated piston liquid is contained in the piston liquid. It is sent to section 303.

Hereinafter, a cargo loading and unloading method by the cargo loading and unloading equipment of the present invention will be described with reference to FIG. In FIG. 8, the dotted line is a moving path of the liquid cargo, and the dashed-dotted line is a moving path of the vapor cargo. Also, the dashed line is the path of travel of the piston liquid, and the three-dot chain is the path of the make-up gas.

The cargo unloading method according to the present invention is characterized in that the two-stage cargo and liquid cargo.

After the liquid cargo in the first cargo container 101 is supplied to the three-phase separator 500 through the liquid recovery valve 131 and the liquid recovery main pipe 140, the liquid cargo through the cargo transfer pump 200. Go through the liquid cargo unloading step to be transferred to the reservoir (701).

When the high pressure liquid cargo exits all from the cargo accommodating container 101 and the water level is lowered, the liquid recovery main pipe 140 is locked to protect the cargo transfer pump 200. In this situation, the cargo accommodating container 101 remains a high-pressure gas phase cargo.

The meteorological cargo unloading step for unloading the remaining high-pressure meteorological cargo is as follows. In the piston liquid supplying step, when the piston liquid is introduced into the cargo accommodating container 101 by opening the liquid supply valve 311, the vapor phase cargo moves to the three-phase separator 500 as it is under high pressure. Thereafter, the gaseous cargo passing through the three-phase separator 500 is subjected to a reliquefaction step in the reliquefaction unit 600. When the gaseous cargo is compressed by the gas cargo compressor 610, the temperature is increased, and the compressed cargo is compressed cargo cooler. Cooling to 620 causes the gaseous cargo to reliquefy into liquid cargo. The reliquefied gaseous phase may be further separated from the non-condensable gas via the compressed cargo separator 630 and then discharged to the external non-condensable gas reservoir 720 through a separate pipe. The reliquefied gaseous cargo is sent to the three-phase separator 500 via the compressed cargo separator level control valve 640 and ultimately unloaded through the cargo transfer pump 200.

After the gas phase cargo unloading step is completed, the piston liquid is recovered through the liquid return valve 131 and sent to the piston liquid receiving portion 301 to reduce the use of the piston liquid. The space of the cargo accommodating container 101 from which the piston liquid has been discharged is subjected to a replenishment gas supply step of filling with a low pressure replenishment gas or evaporated gaseous cargo. In the case of filling with the replenishing gas, the replenishing gas is supplied from the replenishing gas receiving unit 400 and introduced into the cargo receiving container 101 through the replenishing gas main pipe 420 and the replenishing gas valve 411. In the case of using the vaporized gas cargo, a portion of the cargo being unloaded is transferred from the liquid cargo reservoir 702 to be evaporated through the cargo evaporator 710 and supplied to the supplemental gas main pipe 420.

This operation may be performed for each cargo receiving container (101, 102, 103), it can be carried out by separating as a whole. In detail, after the liquid cargo unloading step is performed on all the cargo receiving containers 101, 102, 103 with the cargo transfer pump 200, the gaseous cargo of all the cargo receiving containers 101, 102, 103 is piston liquid injection step and Removal through a reliquefaction step is possible. Alternatively, the gas phase cargo may be removed for each of the cargo containers 101, 102, and 103 by the liquid cargo loading step for each of the cargo containers 101, 102, and 103, and then directly via the vapor cargo loading step.

The present invention is not limited to the above-described embodiments, and the scope of application of the present invention is not limited to those of ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. It goes without saying that various modifications can be made.

1 to 5 is a conventional LPG / CNG transport and unloading method.

6 an embodiment of the cargo loading and unloading equipment of the present invention.

7 is a flow chart of the cargo loading method of the present invention.

8 is a flow chart of the cargo unloading method of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

100, 101, 102, 103: cargo container

110, 111, 112, 113: cargo valve 120: cargo main piping

130, 131, 132, and 133: liquid return valve 140: liquid return main pipe

200: cargo transfer pump

300, 301, 302, 303: piston liquid container

310, 311, 312, 313: liquid supply valve 320: liquid supply main piping

400: replenishment gas receiver

410, 411, 412, 413: make-up gas valve 420: make-up gas main line

500: three-phase separator 600: reliquefaction unit

610: gas cargo compressor 620: compressed cargo cooler

630: compressed cargo separator 640: compressed cargo inflating water level control valve

700, 701, 702 Liquid Cargo Storage 710: Cargo Evaporator

720: non-condensing gas reservoir

Claims (7)

A cargo receiving container 100 for receiving the high pressure liquid cargo and receiving or discharging the cargo from the liquid cargo storage 700 of the cargo receiving base; A cargo transfer pump 200 for discharging the liquid cargo in the cargo receiving container 100 to the liquid cargo storage 700; A piston liquid receiving part 300 which receives a piston liquid which pushes the cargo or is pushed from the cargo during the loading or unloading of the cargo and supplies or recovers the piston liquid to the cargo receiving container 100; A supplement gas receiving unit 400 supplying a supplement gas to the cargo receiving container 100; Cargo loading and unloading equipment for transporting high pressure liquid cargo using a pump and non-mixed driving liquid comprising a. The method of claim 1, A pump comprising a three-phase separator 500 connected to the cargo receiving container 100 and the cargo conveying pump 200 and separating the cargo conveyed from the cargo receiving container 100 into three phases; Cargo loading and unloading equipment for conveying high pressure liquid cargo using unmixed driving liquids. The method of claim 1, Equipment for loading and unloading cargo for transporting high pressure liquid cargo using a pump and non-mixed driving liquid, characterized in that it further comprises a reliquefaction unit 600 for reliquefying the gaseous cargo conveyed from the cargo receiving container (100). The method of claim 2, The reliquefaction unit 600 is a high-pressure liquid phase using a pump and a non-mixed driving liquid, characterized in that it comprises a compressed cargo separator 630 for separating the non-reliquefied gaseous cargo and transported to the non-condensable gas reservoir 720 Cargo loading and unloading equipment for cargo transportation. The method according to any one of claims 1 to 4, The replenishment gas receiving unit 400 is connected to the liquefied reservoir 700 and receives the pump and the non-mixed driving liquid, characterized in that the vaporized cargo discharged from the liquefied reservoir 700 is supplied as a replenishment gas Cargo loading and unloading equipment for high pressure liquid cargo transportation. A liquid cargo unloading step of unloading the liquid cargo conveyed from the cargo accommodating container 100 containing the high pressure liquid cargo into the liquid cargo storage 700 of the cargo receiving base through the cargo transfer pump 200; A vapor phase cargo unloading step of liquefying the vapor phase cargo remaining in the cargo receiving container 100 after the liquid phase cargo loading step and discharging the liquid phase cargo storage 700; A replenishment gas supplying step of filling the cargo receiving container 100 with replenishing gas; Method of unloading high pressure liquid cargo using a pump and a non-mixed driving liquid. The method of claim 6, The gas phase cargo unloading step may include a piston liquid supplying step of supplying a piston liquid into the cargo accommodating container 100 to push the gaseous cargo remaining in the cargo accommodating container 100; And a liquefaction step of liquefying the gaseous cargo discharged from the cargo accommodating container 100 by the piston liquid. The replenishment gas supplying step is to unload the high-pressure liquid cargo using the pump and the unmixed driving liquid, characterized in that after the gas phase cargo unloading step to discharge the piston liquid from the cargo container 100 and at the same time supply the replenishment gas. Way.

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