KR20230016099A - Gas treatment system and ship having the same - Google Patents

Abstract

The present invention relates to a gas treatment system that can quickly clean a filter used to supply liquefied petroleum gas or ammonia as propulsion fuel when foreign substances remain in the filter, and a ship including the same. The gas treatment system comprises: a fuel supply unit that supplies liquefied gas from a liquefied gas storage tank to a propulsion engine; and re-liquefaction unit that includes a compressor compressing boil-off gas from the liquefied gas storage tank, and re-liquefies the compressed boil-off gas. The fuel supply unit includes a high-pressure pump that pressurizes the liquefied gas according to a required pressure of the propulsion engine, a heat exchanger that adjusts temperature of the liquefied gas according to a required temperature of the propulsion engine, and a filter that filters out foreign substances contained in the liquefied gas. The gas treatment system further comprises a filter cleaning unit that removes the residual foreign substances in the filter by blowing a backflush to the filter. The filter cleaning unit blows the boil-off gas compressed by the compressor in the backflush to the filter.

Description

Gas treatment system and ship including the same {Gas treatment system and ship having the same}

The present invention relates to a gas processing system and a vessel including the same.

In general, liquefied petroleum gas, that is, LPG (Liquefied petroleum gas) is obtained by pressurizing and liquefying hydrocarbons with low boiling points such as propane and butane as main components at room temperature. This liquefied petroleum gas is filled in a small and light pressure vessel (cylinder) and widely used as a fuel for home, business, industrial, and automobile purposes.

Liquefied petroleum gas is extracted in a gaseous state at the production site, liquefied and stored through a liquefied petroleum gas processing facility, transported on land while maintaining the liquid phase by a liquefied petroleum gas carrier, and then supplied to consumers in various forms such as gas. do.

Since the boiling point of this liquefied petroleum gas is around -50 ° C, a liquefied petroleum gas carrier for transporting liquefied petroleum gas must maintain a lower temperature than this. Therefore, the liquefied petroleum gas storage tank for storing liquefied petroleum gas uses low-temperature steel (Low Temperature Carbon Steel and Nickel Steel) that is resistant to low temperatures, and a re-liquefaction facility is also provided in the liquefied petroleum gas carrier.

Such a liquefied petroleum gas carrier generated propulsion by operating an engine using diesel oil in the conventional case. However, diesel oil generates nitrogen oxides (NOx), sulfur oxides (SOx), and carbon dioxide (CO2), which are harmful components, in the process of combustion in ship propulsion engines, and these harmful components are released into the atmosphere, thereby polluting the environment. there is.

Therefore, in recent years, development of engines that operate using liquefied petroleum gas and development of various systems for supplying liquefied petroleum gas to the engine have been continuously conducted so that the pollution degree of exhaust can be significantly reduced when compared to the case of using diesel oil. there is.

The present invention has been created to solve the problems of the prior art as described above, and an object of the present invention is to quickly filter when foreign substances remain and differential pressure occurs in a filter for supplying liquefied petroleum gas or ammonia as a propellant fuel. It is to provide a gas processing system that can be washed and reused and a vessel including the same.

A gas processing system according to an aspect of the present invention includes a fuel supply unit for supplying liquefied gas from a liquefied gas storage tank to a propulsion engine; and a re-liquefaction unit having a compressor for compressing boil-off gas in the liquefied gas storage tank and re-liquefying the compressed boil-off gas, wherein the fuel supply unit has a high-pressure pump pressurizing the liquefied gas according to the required pressure of the propulsion engine. ; A heat exchanger for adjusting the temperature of the liquefied gas according to the required temperature of the propulsion engine; and a filter for filtering out foreign substances contained in the liquefied gas, and further comprising a filter washing unit for removing foreign substances remaining in the filter by supplying a reverse flow to the filter, wherein the filter washing unit includes a boil-off gas compressed by the compressor. is supplied as countercurrent to the filter.

Specifically, the fuel supply unit, the high pressure pump, the heat exchanger and the filter are provided and the liquefied gas supply line for delivering the liquefied gas of the liquefied gas storage tank to the propulsion engine; and a differential pressure gauge for measuring differential pressures before and after the filter in the liquefied gas supply line, and the filter washing unit may supply reverse flow to the filter when the measured value of the differential pressure gauge is equal to or greater than a preset value.

Specifically, the filter cleaning unit may allow foreign substances removed from the filter to be transferred to the liquefied gas storage tank along the liquefied gas supply line.

Specifically, the re-liquefaction unit, the compressor for compressing the boil-off gas generated in the liquefied gas storage tank in multiple stages; a condenser condensing the boil-off gas compressed by the compressor; a receiver provided downstream of the condenser; and an intercooler for transferring some of the liquefied boil-off gas separated from the receiver to the liquefied gas storage tank by mutually exchanging heat with the rest, and transferring gas generated by the heat exchange to the compressor. Boiled gas between at least one stage downstream and the condenser may be supplied to the filter.

Specifically, as a system for treating liquefied gas, which is heavy hydrocarbon or ammonia, it may further include a fuel recovery unit for recovering excess liquid liquefied gas discharged from the propulsion engine and transferring it to the fuel supply unit.

Specifically, the filter includes a housing having a liquefied gas inlet through which liquefied gas is introduced and a liquefied gas outlet through which liquefied gas is delivered to the propulsion engine; And a filtering unit provided between the liquefied gas inlet and the liquefied gas outlet in the housing, wherein the housing includes a reverse flow inlet for allowing reverse flow to flow from the filtering unit to the opposite side of the liquefied gas inlet, and the filtering unit It may have a reverse flow outlet such that the reverse flow is discharged in the direction in which the liquefied gas inlet is provided.

A ship according to one aspect of the present invention has the gas treatment system.

The gas processing system according to the present invention and a ship including the same are provided with a filter so that liquefied petroleum gas or ammonia can be used as a fuel for propulsion, but the problem of fuel supply due to foreign substances caught in the filter is quickly resolved to ensure system stability. can be obtained.

1 is a conceptual diagram of a gas processing system according to a first embodiment of the present invention.
2 is a cross-sectional view of a filter of a gas treatment system according to a first embodiment of the present invention.
3 is a conceptual diagram of a gas processing system according to a second embodiment of the present invention.
4 is a conceptual diagram of a gas processing system according to a third embodiment of the present invention.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In adding reference numerals to components of each drawing in this specification, it should be noted that the same components have the same numbers as much as possible, even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

In the present specification, the liquefied gas may be LNG mainly containing methane or LPG (propane, butane, etc.) mainly containing heavy hydrocarbons, but is not limited thereto, and is forced to liquefy for storage due to its boiling point lower than room temperature. All materials with calorific value (propylene, ammonia, hydrogen, etc.) can be included.

In addition, in this specification, it is noted that liquefied gas / evaporative gas is classified based on the state inside the storage tank, and is not necessarily limited to liquid or gaseous phase due to the name.

The present invention includes a vessel equipped with a gas treatment system described below. At this time, the ship is a concept that includes all gas carriers, merchant ships carrying non-gas cargo or people, FSRU, FPSO, bunkering vessels, offshore plants, etc., but it is noted that it may be a liquefied petroleum gas carrier as an example.

Although not shown in the drawing of the present invention, the pressure sensor (PT), the temperature sensor (TT), etc. may be provided at an appropriate location without limitation, of course, and the measured value by each sensor is related to the operation of the components described below. Can be used in a variety of ways without restrictions

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a gas treatment system according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a filter 23 of the gas treatment system according to the first embodiment of the present invention.

1 and 2, the gas processing system 1 according to the first embodiment of the present invention includes a liquefied gas storage tank 10, a fuel supply unit 20, a re-liquefaction unit 30, a fuel recovery unit ( 40), and a filter washing unit 50.

The liquefied gas storage tank 10 stores liquefied gas. The liquefied gas storage tank 10 may be a plurality of cargo tanks provided in a ship that is a liquefied gas carrier. The liquefied gas storage tank 10 may be a tank for storing liquefied gas in a low-temperature liquid phase at atmospheric pressure, and various insulation structures may be added to the wall. In addition, the liquefied gas storage tank 10 may be a membrane type tank or an independent tank, and the shape or specifications thereof are not limited.

A transfer pump 11 may be provided to discharge the liquefied gas in the liquefied gas storage tank 10 to the outside. The transfer pump 11 may be provided inside or outside the liquefied gas storage tank 10, and when provided inside the liquefied gas storage tank 10, it may be provided in a submerged type submerged in liquefied gas.

The transfer pump 11 may be an unloading pump, a stripping pump, a spray pump, etc. for processing liquefied gas as cargo, or a fuel pump provided separately to deliver liquefied gas to the fuel supply unit 20 as fuel. The transfer pump 11 transfers the liquefied gas from the liquefied gas storage tank 10 to the liquefied gas supply line L10 connected to the fuel supply unit 20.

Since the liquefied gas stored in the liquefied gas storage tank 10 is naturally evaporated by external heat penetration, evaporation gas is generated in the liquefied gas storage tank 10 . The boil-off gas may be used as fuel for the propulsion engine E or re-liquefied by the re-liquefaction unit 30 .

The liquefied gas storage tank 10 may be a cargo tank, but may be a fuel tank provided separately from the cargo tank, and may cover both the cargo tank and the fuel tank. The fuel tank may be configured to receive liquefied gas from the cargo tank, and the design pressure and liquefied gas storage pressure may be relatively high compared to the cargo tank. The fuel tank may be a Type C pressure vessel, and unlike a cargo tank mounted inside the hull, it may be placed on the deck. Of course, the arrangement position or type of the fuel tank is not limited.

Between the cargo tank and the fuel tank, liquefied gas or boil-off gas may be provided to be movable, and the fuel tank and the cargo tank may share the re-liquefaction unit 30. At this time, the liquid evaporation gas discharged from the cargo tank and condensed by the re-liquefaction unit 30 may be transferred to the fuel tank, and vice versa.

The fuel supply unit 20 supplies the liquefied gas in the liquefied gas storage tank 10 to the propulsion engine E. In this specification, the propulsion engine (E) is a configuration for propelling a ship, and can be interpreted as any configuration capable of directly or indirectly generating propulsion by consuming liquefied gas, such as a turbine or a fuel cell, other than an engine.

The liquefied gas of the liquefied gas storage tank 10 is delivered to the propulsion engine E by the liquefied gas supply line L10 extending from the liquefied gas storage tank 10, and the fuel supply unit 20 is a liquefied gas supply line ( It includes a high-pressure pump 21, a heat exchanger 22, a filter 23, etc. provided on L10).

The high-pressure pump 21 pressurizes the liquefied gas according to the required pressure of the propulsion engine E. A plurality of high-pressure pumps 21 may be provided to enable mutual backup, and may be of a centrifugal type, a reciprocating type, a screw type, and the like.

In order to prevent cavitation, the high-pressure pump 21 has a suction pressure set higher than the critical pressure of the liquefied gas, or lower than the critical pressure, and vaporization does not occur even at the highest temperature (around 50 degrees Celsius) of the liquefied gas in the system. It may be a level of pressure that does not.

Alternatively, as a cooler (not shown) is provided in the fuel recovery unit 40, vaporization in the high-pressure pump 21 may be prevented. This will be described later.

The heat exchanger 22 adjusts the temperature of the liquefied gas according to the required temperature of the propulsion engine E. The heat exchanger 22 may be provided upstream of the high-pressure pump 21 and downstream of the high-pressure pump 21, but unlike the drawings, it may be provided at either a downstream or upstream location of the high-pressure pump 21.

Since the heat exchanger 22 may increase or decrease the temperature of liquefied gas, it may also be referred to as a fuel conditioner. For example, at the time of initial operation of this embodiment, since the flow rate of the high-temperature liquefied gas recovered from the propulsion engine E is large, the heat exchanger 22 can lower the temperature of the liquefied gas, and when entering into stable operation, the heat exchanger (22) can increase the temperature of the liquefied gas.

The heat exchanger 22 may implement heat exchange with liquefied gas using various fruits supplied by a fruit supply unit (not shown). For example, the fruit may be seawater, fresh water, glycol water, exhaust, etc., but this It is not limited.

The filter 23 filters out foreign substances contained in the liquefied gas. When the liquefied gas is liquefied petroleum gas, the foreign matter may be a particle having a size of 100 μm or more, or any other material unsuitable for supply to the propulsion engine E.

The filter 23 may be provided upstream of the high pressure pump 21 or downstream of the high pressure pump 21 . As shown in the drawing, the filter 23 may be provided both upstream and downstream of the high pressure pump 21, or unlike the drawing, the filter 23 may be provided only downstream of the high pressure pump 21.

In addition, a plurality of filters 23 are provided in parallel at one point on the liquefied gas supply line L10, one filter 23 filters out foreign substances, and the other filter 23 can be provided as a backup. there is. For example, when one of the filters 23 is washed by the filter washing unit 50, foreign substances in the liquefied gas may be filtered out by the other filter 23.

The filter 23 is a component that continuously removes foreign substances contained in the liquefied gas, and foreign substances may remain in the filter 23 in the process of consuming the liquefied gas. If a foreign substance is stuck in the filter 23, the flow of liquefied gas that needs to pass through the filter 23 is hindered, so it must be continuously removed. As a result, fuel supply may not be operated.

Therefore, cleaning to remove foreign substances is required for the filter 23, which will be described in the filter cleaning unit 50 below. However, a differential pressure gauge (not shown) for measuring the differential pressure before and after the filter 23 may be provided in the liquefied gas supply line L10 where the filter 23 is provided, and the filter cleaning unit 50 to be described later may measure the differential pressure gauge. Depending on the value, control of filter 23 washing can be implemented.

The re-liquefying unit 30 compresses and re-liquefies the boil-off gas in the liquefied gas storage tank 10 and returns it to the liquefied gas storage tank 10 or supplies it to the propulsion engine E. The re-liquefaction unit 30 may include a compressor 31, a condenser 32, a receiver 33, and an intercooler 34, and the boil-off gas liquefaction line L20 extends from the liquefied gas storage tank 10 It may be connected to the liquefied gas storage tank 10 after passing through each component of the re-liquefaction unit 30 .

The compressor 31 compresses the boil-off gas generated in the liquefied gas storage tank 10 in multiple stages (eg, three stages). The compressor 31 may be of a centrifugal or reciprocating type, and may be provided in multiple stages including a plurality of compression stages. Compressors 31 may also be arranged in parallel for backup or load sharing.

The compressor 31 may compress the boil-off gas introduced at around 1 bar to 10 to 100 bar, and when the boil-off gas is compressed by the compressor 31, the boiling point of the boil-off gas rises. Therefore, the compressed boil-off gas can be liquefied without cooling to the boiling point at atmospheric pressure (for example, -55 degrees in the case of LPG).

A plurality of compression stages are provided in series in the boil-off gas liquefaction line (L20) extending from the liquefied gas storage tank 10 to the condenser 32 to form a multi-stage compressor 31, on the boil-off gas liquefaction line (L20). An intercooler 34 may be connected to an intermediate end between compression ends.

At this time, as will be described later, the intercooler 34 is a cooling facility using decompressed boil-off gas as a refrigerant without a separate refrigerant, and can cool the low-pressure boil-off gas or medium-pressure boil-off gas introduced from the compressor 31. Accordingly, the intercooler 34 may implement cooling at the middle stage of the compressor 31 .

The condenser 32 cools the compressed boil-off gas to re-liquefy at least a portion thereof. At this time, the condenser 32 may re-liquefy the boil-off gas, but it should be noted that the situation in which the boil-off gas is not re-liquefied at all or only part of the boil-off gas is re-liquefied due to various factors during actual operation is not excluded.

This is because substances with different boiling points are mixed in the evaporation gas. For example, in the case of LPG containing propane and butane as main components but containing ethane, some components such as ethane may not be re-liquefied because the boiling point of ethane is lower than that of propane/butane.

The condenser 32 is provided downstream of the multi-stage compressor 31, and uses various refrigerants (eg seawater, fresh water, glycol water, nitrogen, LNG, LPG, propane, R134a, CO2, etc.) that are not limited to Boiled gas can be cooled.

The condenser 32 may not lower the temperature of the boil-off gas compressed by the compressor 31 to the boiling point of the boil-off gas at atmospheric pressure. This is because the boiling point increases as the boil-off gas is compressed by the compressor 31 . However, the condenser 32 may adjust the cooling temperature of the boil-off gas in consideration of the pressure of the boil-off gas discharged from the compressor 31 of the final stage.

The receiver 33 temporarily stores boil-off gas liquefied in the condenser 32 . The receiver 33 may be a gas-liquid separator, and may transfer liquefied boil-off gas among the cooled boil-off gas to the intercooler 34 .

However, the receiver 33 may store the non-liquefied boil-off gas among the cooled boil-off gas without discharging it to the outside, and in this case, as the internal pressure of the receiver 33 increases, the effect of liquefying the boil-off gas can be improved.

Between the condenser 32 and the liquefied gas storage tank 10, a boil-off gas liquefaction line (L20) is provided to transfer the cooled boil-off gas to the liquefied gas storage tank 10, and the receiver 33 is a boil-off gas liquefaction line. (L20) downstream of the condenser 32 and upstream of the intercooler 34.

However, the receiver 33 may be omitted, and in this case, the evaporation gas cooled in the condenser 32 may be transferred to the intercooler 34 without separate gas-liquid separation.

The intercooler 34 mutually exchanges heat with a part of the boil-off gas liquefied in the condenser 32 and the rest. A boil-off gas branch line (not shown) is branched in the boil-off gas liquefaction line (L20) upstream of the intercooler 34, and a pressure reducing valve (not shown) is provided on the boil-off gas branch line. Since one end has an open shape inside the intercooler 34, the evaporation gas that has passed through the pressure reducing valve can be filled inside the intercooler 34.

The pressure reducing valve provided in the evaporation gas branch line reduces the evaporation gas branched upstream of the intercooler 34 after being cooled by the condenser 32 . The boil-off gas liquefaction line (L20) passes through the inside of the intercooler 34 and has a flow connected to the liquefied gas storage tank 10, while the boil-off gas branch line equipped with a pressure reducing valve is inside the intercooler 34. can be injected.

In this case, the pressure reducing valve reduces and cools the boil-off gas so that the boil-off gas filled in the intercooler 34 can be used as a refrigerant (Joule-Thomson effect), so that stable liquefaction is possible by heat exchange of the boil-off gas itself without a separate refrigerant. can

The pressure reducing valve may be a Joule-Thomson valve or may be replaced by an expander. The evaporation gas cooled in the condenser 32 and then reduced in pressure by the pressure reducing valve may be further liquefied by cooling generated during pressure reduction.

In this case, the boil-off gas reduced by the pressure reducing valve flows into the intercooler 34 separately from the boil-off gas not passing through the pressure-reducing valve, and the boil-off gas liquefied by the reduced pressure may be used as a refrigerant in the intercooler 34.

Two or more intercoolers 34 may be provided, and a pressure reducing valve may be provided for each boil-off gas branch line branched from upstream of each intercooler 34 in the boil-off gas liquefaction line L20 and connected to the intercooler 34. there is.

The intercooler 34 may serve as a cooler in the middle of the compressor 31 upstream of the condenser 32 . The intercooler 34 is connected to the middle stage of the compressor 31 in the boil-off gas liquefaction line L20, and cools the boil-off gas compressed by some of the plurality of compression stages of the compressor 31 using the reduced boil-off gas. It can be, and the boil-off gas generated by heat exchange can be delivered to the compressor 31.

After being liquefied in the condenser 32, the liquid evaporation gas that has passed through the receiver 33 and the intercooler 34 has a pressure similar to the internal pressure of the liquefied gas storage tank 10 by a pressure control valve (not shown). After additional cooling while falling, it can be returned to the liquefied gas storage tank (10).

In addition, a gas-liquid separator is provided between the intercooler 34 and the liquefied gas storage tank 10, and the evaporation gas of the liquid phase is supplied to the liquefied gas storage tank 10 and the evaporation gas of the vapor phase can be delivered to the condenser 32 and the like. there is.

The fuel recovery unit 40 recovers excess liquefied gas discharged from the propulsion engine E. The propulsion engine (E) of this embodiment may be an engine (ME-LGI, etc.) that receives liquefied gas as a liquid phase, and when compared to an engine (ME-GI, X-DF, etc.) that receives liquefied gas as a gas phase, the flow rate Fine-tuning is difficult. Therefore, the propulsion engine (E) may be configured to receive the liquefied gas at a required flow rate or more and discharge the surplus liquefied gas.

At this time, the liquefied gas discharged from the propulsion engine (E) is a liquefied gas that has passed through the inside of the propulsion engine (E), and has a temperature / pressure corresponding to the required pressure of the propulsion engine (E) (for example, around 45 bar, 50 degrees Celsius or more), the lubricant used in the propulsion engine (E) may have been mixed. In this case, in order to prevent cargo contamination, it is preferable not to transfer the recovered liquefied gas to the liquefied gas storage tank 10 (especially the cargo tank).

Therefore, the liquefied gas recovery line (L30) connected to the propulsion engine (E) so that the surplus liquefied gas is recovered is a fuel supply unit (not the liquefied gas storage tank 10) that surplus liquefied gas returned from the propulsion engine (E) 20) may be transferred to the high-pressure pump 21 or the like so as to be re-introduced into the propulsion engine E.

The fuel recovery unit 40 includes a pressure reducing valve (symbol not shown), a cooler symbol not shown) provided in the liquefied gas recovery line (L30), and the liquefied gas branched off from the liquefied gas recovery line (L30). It includes a collection tank 41 connected to the branch line L31, a knockout drum 42, and the like.

The pressure reducing valve reduces the pressure of the liquid liquefied gas. The pressure reducing valve may be a Joule-Thomson valve, and may constitute a fuel supply train (FVT) together with a fuel supply valve provided in the liquefied gas supply line (L10). This pressure reducing valve can reduce the high pressure (about 30 to 50 bar) liquefied gas recovered from the propulsion engine (E) to match the suction pressure of the high pressure pump (21).

The cooler cools the liquefied gas pressure-reduced by the pressure-reducing valve and delivers it to the high-pressure pump 21. The cooler may utilize various refrigerants that are not limited, and may cool the liquefied gas below the boiling point of the reduced pressure liquefied gas. However, since the boiling point may vary depending on the inlet pressure of the liquefied gas flowing into the high-pressure pump 21, the cooler may be omitted in consideration of this.

The liquefied gas cooled by the cooler is mixed upstream of the high-pressure pump 21 in the liquefied gas supply line (L10) through the liquefied gas recovery line (L30), and the liquefied gas recovery line (L30) is connected to the liquefied gas supply line ( A mixer (not shown) may be provided at a point connected to L10).

The collection tank 41 separates the liquefied gas recovered from the propulsion engine E into gas and liquid. Since cavitation problems may occur when gaseous liquefied gas flows into the high-pressure pump 21, the present invention provides gas-liquid separation while passing through the collection tank 41 as needed for the liquefied gas flowing along the liquefied gas recovery line L30. As such, it is possible to block the inflow of the gaseous liquefied gas into the high-pressure pump 21.

That is, the collection tank 41 collects at least a portion of the liquefied gas in the liquefied gas recovery line L30 and transfers only the liquefied gas to the high-pressure pump 21, thereby ensuring stable operation of the high-pressure pump 21.

The collection tank 41 is connected in parallel to the flow of liquefied gas delivered from the pressure reducing valve to the high pressure pump 21. That is, instead of being provided on the liquefied gas recovery line (L30), the collection tank 41 will be connected to a liquefied gas branch line (L31) branched downstream of the pressure reducing valve (and upstream of the cooler) in the liquefied gas recovery line (L30). can

That is, the liquefied gas reduced by the pressure reducing valve is transferred to the high pressure pump 21 via the collection tank 41 through the liquefied gas branch line L31, or the collection tank 41 through the liquefied gas recovery line L30. It can be transferred to the high-pressure pump 21 by bypassing, and whether to pass through the collection tank 41 can be controlled according to the flow rate or temperature of the liquefied gas discharged from the propulsion engine (E).

The liquefied gas branched from the collection tank 41 may be delivered to the knockout drum 42 . The knockout drum 42 may receive the liquefied gas recovered from the propulsion engine E from the collection tank 41 and filter impurities (lubricating oil, etc.) contained in the liquefied gas. Specifically, the knockout drum 42 discharges liquefied gas in the gas phase and discharges the lubricating oil in the liquid phase. That is, the knockout drum 42 implements a gas-liquid separation function similar to the collection tank 41 .

The knockout drum 42 may use a heating unit such as tracing to promote vaporization of liquefied gas, and the tracing may use a medium such as steam or seawater as a heat source or may be heated using electricity. there is.

The knockout drum 42 heats liquefied gas mixed with lubricating oil with a heating unit, discharges the liquefied gas to a vent mast (not shown), etc., and drains the lubricating oil from the bottom to process (recycle).

The filter washing unit 50 removes foreign substances remaining in the filter 23 by supplying (blowing) a reverse flow to the filter 23 (back flushing). As mentioned above, a differential pressure gauge may be provided in the liquefied gas supply line L10, and when the measured value of the differential pressure gauge is greater than a predetermined value, the filter washing unit 50 may supply reverse flow to the filter 23.

In this case, as described above, after the inflow of liquefied gas is blocked in one filter 23 that filters out foreign substances, washing is performed, and the other filter 23 that was in a standby state can filter out foreign substances. , Change over of the filter 23 can be made through a valve (not shown).

Hereinafter, the structure of the filter 23, which is the object to be cleaned by the filter washing unit 50, will be described with reference to FIG. 2.

Referring to FIG. 2, the filter 23 has a housing 231 and a filtering unit 232, and the housing 231 has a liquefied gas inlet 231a into which liquefied gas is introduced, and a liquefied gas propulsion engine (E). It has a liquefied gas outlet (231b) passing to, and a filtering unit 232 is provided therein.

At this time, the filtering unit 232 is provided between the liquefied gas inlet 231a and the liquefied gas outlet 231b in the housing 231, and foreign substances contained in the liquefied gas are caught by the filtering unit 232 and the propulsion engine (E ) to prevent supply.

However, if foreign substances remain excessively in the filter 232, the flow rate of the liquefied gas passing through the filter 23 is greatly reduced, and fuel supply may become unstable. Accordingly, in the present embodiment, the reverse flow is supplied to the filter 23 using the filter washing unit 50, and the reverse flow flows into the reverse flow inlet 231c provided in the housing 231.

The housing 231 is provided with a reverse flow inlet 231c for allowing a reverse flow to flow on the opposite side of the liquefied gas inlet 231a in the sieving portion 232, and the direction in which the liquefied gas inlet 231a is provided in the sieving portion 232. A reverse flow outlet 231d is provided so that the reverse flow is discharged.

Therefore, the liquefied gas passes through the sifter 232 in the first direction between the liquefied gas inlet 231a and the liquefied gas outlet 231b, and the reverse flow is between the reflux inlet 231c and the reflux outlet 231d. By passing through the filter 232 in the second direction (opposite to the first direction), foreign substances filtered in the filtering unit 232 may be separated from the filtering unit 232 .

At this time, the reverse flow containing foreign matter may be returned to the liquefied gas storage tank 10 along the liquefied gas supply line L10, or may be stored in a separate foreign matter storage tank (not shown).

The filter washing unit 50 may remove foreign substances in the filter 232 by injecting a reverse flow into the filter 23, and at this time, the evaporation gas compressed by the compressor 31 may be used as the reverse flow. That is, the filter washing unit 50 uses the compressor 31 of the re-liquefying unit 30 to inject high-pressure gas into the filter 23 instead of using a separate countercurrent flow, so that the filter 23 is quickly regenerated. can make it happen.

Specifically, the filter washing unit 50 may supply boil-off gas between at least one stage downstream of the multi-stage compressor 31 provided in the re-liquefaction unit 30 and the condenser 32 to the filter 23, and for this purpose, the re-liquid A filter washing line (L40) may be connected from the fire unit 30 to the filter 23 of the liquefied gas supply line (L10).

A filter washing valve 51 is provided in the filter washing line L40, and the filter washing unit 50 opens the filter washing valve 51 when it is determined that cleaning of the filter 23 is required, thereby opening the filter washing line L40. ) through which the reverse flow can be passed to the filter 23.

At this time, the filter washing valve 51 may be a valve that serves as the main isolation of the filter washing line L40, and downstream of the branching point to each filter 23 at the downstream of the filter washing valve 51, each filter An inlet valve (not shown) for blowing of (23) may be provided.

The filter washing line (L40) may be branched between the middle end of the compressor 31 or between the final end of the compressor 31 and the condenser 32 and extend to the filter 23, and the filter 23 may be connected according to the measured value of the differential pressure gauge. It may be provided that the pressure of the evaporation gas supplied towards the is different. For example, when the measured value of the differential pressure gauge exceeds the first set value, the evaporation gas downstream of the first stage of the compressor 31 is supplied to the filter 23, and the measured value of the differential pressure gauge sets a second set value greater than the first set value. If exceeded, the evaporation gas of the second stage downstream of the compressor 31 may be supplied to the filter 23.

Alternatively, the supply pressure of the boil-off gas may vary according to the time for cleaning. For example, when quick cleaning is required, boil-off gas from the second stage downstream of the compressor 31 may be used. In addition, the boil-off gas pressure in the reliquefaction unit 30 used by the filter washing unit 50 may be variously determined according to the structure and type of the filter 23 .

In addition, the filter washing line (L40) is provided to directly inject the boil-off gas compressed by the compressor 31 into the filter 23, or is connected to the downstream of the filter 23 in the liquefied gas supply line (L10) to supply liquefied gas. The boil-off gas may be injected into the filter 23 through the line L10.

That is, the filter washing unit 50 directly transfers the boil-off gas to the filter 23 as necessary to implement cleaning of the filter 23, or transfers the boil-off gas to the liquefied gas supply line L10 to supply the liquefied gas supply line ( L10) and components downstream of the filter 23 (for example, the heat exchanger 22, etc.) may be cleaned at once.

In this way, in this embodiment, foreign substances can be quickly removed by using the boil-off gas compressed in the re-liquefaction unit 30 with respect to the filter 23 for which the differential pressure is detected as high, and after a certain time, the backflow supply is stopped and washing is completed. Since the filter 23 can be reused, system operation stability can be guaranteed.

3 is a conceptual diagram of a gas processing system 1 according to a second embodiment of the present invention.

Hereinafter, the present embodiment will be described mainly in terms of differences from the previous embodiment.

Referring to FIG. 3 , the gas processing system 1 (1) according to the second embodiment of the present invention includes a fuel supply unit 20, a re-liquefaction unit 30, a fuel recovery unit 40, and the like, as in the previous embodiment. Including, a filter 23 is provided on at least one side of the upstream and downstream of the high pressure pump 21 in the fuel supply unit 20, and the filter 23 is cleaned based on the differential pressure before and after the filter 23. A washing unit 50 may be provided. However, the filter cleaning unit 50 of the present embodiment allows the filter 23 to be cleaned in the fuel supply unit 20 itself even without using the compressed boil-off gas of the reliquefaction unit 30 .

The filter 23 of this embodiment is provided on the liquefied gas supply line L10, and a bypass line L11 capable of bypassing the filter 23 is provided in the liquefied gas supply line L10. The bypass line (L11) is provided with a bypass valve (not shown) capable of opening and closing control, and is opened when it is determined that the liquefied gas does not need to pass through the filter 23 in the fuel supply process, or the filter ( 23) may be opened by the filter washing unit 50 during cleaning.

For example, when cleaning of the filter 23 is required, the filter cleaning unit 50 flows the liquefied gas downstream of the filter 23 through the bypass line L11 and then transfers it to the filter 23 in reverse. so that it is provided as a countercurrent to the filter 23. At this time, the foreign substances remaining in the filter 23 may be removed from the filter 232 by countercurrent flow and returned to the liquefied gas storage tank 10 together with the liquefied gas.

In the case of this embodiment, instead of using the reverse flow inlet 231a and the reverse flow outlet 231d in FIG. 2, the liquefied gas inlet 231a and the liquefied gas outlet 231b are switched as the inlet and outlet of the reverse flow, respectively. Can be used.

Of course, in this embodiment, as in FIG. 2, the inflow and outflow of the reverse flow can be made independently of the liquefied gas in the filter 23, and for this purpose, the liquefied gas supply line (L10) or the bypass line (L11) can be properly connected .

In this way, in this embodiment, unlike the previous embodiment using the boil-off gas compressed in the compressor 31 of the re-liquefaction unit 30, as the liquefied gas is directly used, the washing time of the filter 23 is increased compared to the previous embodiment. However, power consumption can be reduced.

4 is a conceptual diagram of a gas treatment system 1 according to a third embodiment of the present invention.

For reference, in the case of FIGS. 1 to 3, the liquefied gas may be LPG or ammonia, and in the case of FIG. 4, the liquefied gas may be LNG.

Referring to FIG. 4 , a gas processing system 1 according to a third embodiment of the present invention includes a fuel supply unit 20 , a reliquefaction unit 30 , and a filter cleaning unit 50 . At this time, in this embodiment, the engines E and D may be provided in a plurality having different required pressures, such as the propulsion engine E and the power generation engine D, and the fuel supply unit 20 may have a plurality of different required pressures. It is provided to supply liquefied gas to the engines E and D at different pressures so as to be suitable for the engines E and D. In addition, the fuel supply unit 20 may supply boil-off gas as well as liquefied gas as fuel for the engines E and D.

Specifically, in the fuel supply unit 20, the liquefied gas discharged from the liquefied gas storage tank 10 through the transfer pump 11 passes through the filter 23 or passes through the filter 23 along the bypass line L11. It is bypassed and branched along the liquefied gas supply line (L10) so that at least a part is transmitted to the propulsion engine (E) in a high pressure state via the high pressure pump 21 and the heat exchanger 22.

In addition, the fuel supply unit 20 is branched along the liquefied gas supply line L10 downstream of the filter 23, and at least part of it passes through the vaporizer 24 to the power generation engine D in a low pressure state (boiler, gas combustion device) etc.) can be passed on.

Furthermore, after the fuel supply unit 20 is heated to an appropriate temperature through the gas heater 25 after the boil-off gas discharged from the liquefied gas storage tank 10 is compressed by the compressor 31 (gas heater 25) can be omitted), if necessary, the liquefied gas downstream of the vaporizer 24 is mixed and supplied to the power generation engine D. To this end, a boil-off gas supply line (L50) toward the power generation engine (D) may be provided downstream of the compressor 31 in the boil-off gas liquefaction line (L20).

This embodiment also includes a filter washing unit 50 that monitors the differential pressure before and after the filter 23 and cleans the filter 23 accordingly. The filter washing unit 50 can utilize both the configurations of the previous two embodiments. . That is, the filter washing unit 50 of the present embodiment, as in the first embodiment, passes the high-pressure evaporation gas compressed in the compressor 31 through the filter washing line L40 equipped with the filter washing valve 51 to the filter ( By injecting into 23) as a reverse flow, foreign substances caught in the filter 23 are returned to the liquefied gas storage tank 10.

And/or the filter washing unit 50 may allow liquefied gas, which may flow into the filter 23 as a countercurrent along the bypass line L11, to remove foreign substances in the filter 23. The filter cleaning unit 50 may reversely inject liquefied gas into the filter 23 by appropriately opening and closing a bypass valve (not shown) provided in the bypass line L11.

In this way, in the present embodiment, in the system for supplying LNG as fuel, back flushing is automatically performed according to the differential pressure to the filter 23 provided during the fuel supply of liquefied gas, thereby clogging and The maintenance cycle can be minimized, and foreign substances are returned to the liquefied gas storage tank 10, so there is no need to prepare a separate foreign substance treatment line or related configuration.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, the present invention is not limited thereto, and within the technical spirit of the present invention, by those skilled in the art It will be clear that the modification or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific protection scope of the present invention will be clarified by the appended claims.

1: gas processing system 10: liquefied gas storage tank
11: transfer pump 20: fuel supply unit
21: high pressure pump 22: heat exchanger
23: filter 231: housing
231a: liquefied gas inlet 231b: liquefied gas outlet
231c: backflow inlet 231d: backflow outlet
232: filter 24: vaporizer
25: gas heater 30: re-liquefaction unit
31: compressor 32: condenser
33: receiver 34: intercooler
40: fuel recovery unit 41: collection tank
42: knockout drum 50: filter washing unit
51: filter cleaning valve L10: liquefied gas supply line
L11: bypass line L20: boil-off gas liquefaction line
L30: liquefied gas recovery line L31: liquefied gas branch line
L40: filter washing line L50: boil-off gas supply line
E: propulsion engine D: power generation engine

Claims (7)

A fuel supply unit supplying liquefied gas from the liquefied gas storage tank to the propulsion engine; and
It has a compressor for compressing the boil-off gas of the liquefied gas storage tank, and includes a re-liquefaction unit for re-liquefying the compressed boil-off gas,
The fuel supply unit,
a high-pressure pump that pressurizes liquefied gas according to the required pressure of the propulsion engine;
A heat exchanger for adjusting the temperature of the liquefied gas according to the required temperature of the propulsion engine; and
It includes a filter for filtering out foreign substances contained in liquefied gas,
Further comprising a filter washing unit for removing foreign substances remaining in the filter by supplying a reverse flow to the filter,
The filter washing unit,
Gas processing system for supplying the boil-off gas compressed in the compressor to the filter as a countercurrent. The method of claim 1, wherein the fuel supply unit,
a liquefied gas supply line provided with the high-pressure pump, the heat exchanger, and the filter and transferring the liquefied gas in the liquefied gas storage tank to the propulsion engine; and
Including a differential pressure gauge for measuring the differential pressure before and after the filter in the liquefied gas supply line,
The filter washing unit,
A gas treatment system for supplying a reverse flow to the filter when the measured value of the differential pressure gauge is equal to or greater than a predetermined value. The method of claim 2, wherein the filter washing unit,
Gas processing system that allows foreign substances removed from the filter to be transferred to the liquefied gas storage tank along the liquefied gas supply line. The method of claim 1, wherein the re-liquefaction unit,
The compressor for compressing the boil-off gas generated in the liquefied gas storage tank in multiple stages;
a condenser condensing the boil-off gas compressed by the compressor;
a receiver provided downstream of the condenser; and
And an intercooler for transferring some of the liquefied boil-off gas separated from the receiver to the liquefied gas storage tank by mutually exchanging heat with the rest, and conveying the gaseous phase generated by the heat exchange to the compressor,
The filter washing unit,
The gas treatment system of claim 1 , wherein boil-off gas between at least one stage downstream of the compressor and the condenser is supplied to the filter. According to claim 1,
A system for treating liquefied gas, which is heavy hydrocarbon or ammonia,
The gas processing system further comprises a fuel recovery unit for recovering excess liquefied gas discharged from the propulsion engine and transferring it to the fuel supply unit. The method of claim 1, wherein the filter,
A housing having a liquefied gas inlet through which liquefied gas flows and a liquefied gas outlet through which liquefied gas is transferred to the propulsion engine; and
And a manure provided between the liquefied gas inlet and the liquefied gas outlet in the housing,
the housing,
A gas processing system having a reverse flow inlet for allowing a reverse flow to flow into the opposite side of the liquefied gas inlet in the manure, and a reverse flow outlet for allowing a reverse flow to be discharged from the manure in a direction in which the liquefied gas inlet is provided. A vessel having the gas treatment system according to any one of claims 1 to 6.

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