KR20190123455A - gas treatment system and offshore plant having the same - Google Patents

Abstract

According to one embodiment of the present invention, a gas treatment system includes: a re-liquefying device heat-exchanging a refrigerant and gas and re-liquefying the gas; a vapor-liquid separator supplied with the gas at least partially re-liquefied in the re-liquefying device to separate the same into vapor and liquid, supplying the vapor gas to a boil off gas compressor to use the same as fuel, and producing the liquid gas as liquefied gas to supply the same to a liquefied gas storage tank; and a surge preventing device preventing surge generation of the boil off gas compressor, wherein the surge preventing device vaporizes at least a part of the at least partially re-liquefied gas discharged from the re-liquefying device and increases a flow rate of the vapor supplied to the boil off gas compressor when the surge is generated in the boil off gas compressor.

Description

Gas treatment system and offshore plant having the same

The present invention relates to a gas treatment system and a marine float comprising the same.

As environmental regulations have recently been tightened, the use of natural gas, which is close to an environmentally friendly fuel, is increasing among various fuels. Natural gas can be extracted in gaseous form from inland or offshore gas wells, and the natural gas can be liquefied through liquefaction for storage and transportation after pretreatment such as mercury removal, drying or NGL removal. Can be.

Natural gas can be cooled to below the boiling point (for example, -162 ℃ under 1 atm) while being exchanged with a refrigerant, and can be converted into a liquid state. Transport efficiency can be increased.

The liquefaction process as described above may be performed in a land plant or FLNG on the sea, and liquefied natural gas may be stored in an LNG storage tank and then supplied to a consumer.

For example, natural gas may be supplied from LNG storage tanks to onshore city gas facilities or power generation facilities, or may be delivered to cargo tanks of LNG carriers and transported to desired areas by LNG carriers.

At this time, the natural gas may be consumed by being vaporized after being discharged from the LNG storage tank or cargo tank, the vaporization facility may be provided in a land plant or FLNG, or in a facility that consumes natural gas.

As such, natural gas is extracted from gas wells and consumed through pre-treatment, liquefaction, storage, transportation, and gasification processes in turn. Various research and development is conducted to ensure stability and improve efficiency of gas production, treatment, and supply. This is constantly being done.

SUMMARY OF THE INVENTION The present invention has been made to improve the prior art, and an object of the present invention is to provide a gas treatment system and a marine float comprising the same to ensure the stable productivity of the liquefied gas and increase operating reliability and reduce system operating costs. It is for.

According to an aspect of the present invention, there is provided a gas treatment system comprising: a reliquefaction apparatus for reliquefying a gas by exchanging a refrigerant and a gas; The at least partly reliquefied gas is supplied from the reliquefaction apparatus to be separated into a gaseous phase and a liquid phase, and the gaseous gas is supplied to an evaporative gas compressor to be used as a fuel, and the liquid gas is produced as a liquefied gas. A gas-liquid separator supplied to the storage tank; And a surge protection device for preventing a surge of the boil-off gas compressor, wherein the surge protection device includes at least partially reliquefied discharged from the re-liquefaction device when a surge occurs in the boil-off gas compressor. At least a part of the gas is vaporized to increase the flow rate of the gas phase supplied to the boil-off compressor.

Specifically, the surge prevention device is formed of an electric heater, disposed between the reliquefaction apparatus and the gas-liquid separator, to at least partially vaporize the at least partially re-liquefied gas discharged from the re-liquefaction apparatus to the gas-liquid separator By supplying to the gas, the flow rate of the gas phase separated in the gas-liquid separator can be increased.

Specifically, the surge protection device, when the at least partly reliquefied gas starts to be supplied to the gas-liquid separator in the reliquefaction apparatus, the surge protection device is heated to supply the at least partially reliquefied gas to the gas-liquid separator The temperature of at least some reliquefied gas can be raised.

Specifically, the gas supply unit further comprises a gas demand source for receiving and consuming the compressed gas from the boil-off gas compressor, wherein the surge prevention device, at least part of the ash discharged from the reliquefaction apparatus when the amount of gas required by the gas demand destination is insufficient. At least a part of the liquefied gas may be vaporized to increase the flow rate of the gaseous phase supplied to the boil-off compressor.

Specifically, a reliquefaction supply line connecting the reliquefaction apparatus and the gas-liquid separator, the reliquefaction supply line having the surge prevention device; And a gas supply line connecting the gas-liquid separator and the gas demand destination.

Specifically, liquefied gas storage tank for storing the liquefied gas; And a scrubber provided upstream of the boil-off gas compressor, wherein the gas-liquid separator may supply the liquefied gas to the liquefied gas storage tank or the scrubber.

Specifically, the gas-liquid separator may supply the liquefied gas to the scrubber in order to adjust the temperature of the gas in the gaseous phase supplied to the boil-off gas compressor.

Specifically, a reliquefaction supply line connecting the reliquefaction apparatus and the gas-liquid separator, the reliquefaction supply line having the surge prevention device; A gas supply line connecting the gas-liquid separator and the gas demand destination; A liquefied gas recovery line connecting the gas-liquid separator and the liquefied gas storage tank; And a temperature control line connecting the gas-liquid separator and the scrubber.

Specifically, the main surge prevention device is configured to connect the upstream and downstream of the boil-off gas compressor, and when the surge of the boil-off gas compressor occurs, supplying the boil-off gas discharged downstream of the boil-off gas compressor back upstream of the boil-off gas compressor. Further comprising, the surge protection device, as an auxiliary surge prevention device, may operate in an auxiliary manner to the main surge protection device.

Specifically, the main surge prevention device, the bypass line configured to connect the upstream and downstream of the boil-off gas compressor; And a bypass valve formed on the bypass line.

Specifically, it may be a marine float, characterized in that it comprises the gas treatment system.

The gas treatment system and the marine float including the same according to the present invention can prevent the solidification of the fluid flowing in the heat exchanger through the value of the pressure difference between the inlet and the outlet of the heat exchanger, thereby reducing the system operating cost. And the operation reliability is improved.

In addition, the gas treatment system and the marine float comprising the same according to the present invention, by placing an electric heater upstream of the boil-off gas compressor, to increase the amount of gas flowing into the boil-off gas compressor when a surge risk occurs to prevent the occurrence of surge As a result, operation reliability is improved and a stable system can be realized.

In addition, the gas treatment system according to the present invention and the marine float comprising the same, by placing an electric heater upstream of the boil-off gas compressor, it is possible to increase the amount of gas flowing into the boil-off gas compressor when the gas demand is short of the gas demand source This has the effect of ensuring a sufficient fuel supply and the effect of improving the reliability of system operation.

In addition, the gas treatment system and the marine float including the same according to the present invention, by placing an electric heater upstream of the gas-liquid separator separating the liquefied gas into gaseous and liquid phase (Thermal shock change of the gas-liquid separator at the initial operation of the system) ), Which improves the durability of the system.

1 is a conceptual diagram of a gas treatment system according to an embodiment of the present invention.
2 is a conceptual diagram of a gas treatment system according to another embodiment of the present invention.
3 is a conceptual diagram of a gas treatment system according to an exemplary embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the gas may mean a material having a boiling point lower than room temperature as LPG, LNG, ethane, or the like.

Hereinafter, a gas treatment system of the present invention will be described, and the present invention includes a gas treatment system and a marine float having the same. In this case, it is noted that the marine floats are not only an offshore plant such as FLNG and FSRU, but also a general merchant vessel.

1 is a conceptual diagram of a gas treatment system according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of a gas treatment system according to another embodiment of the present invention.

1 and 2, the gas treatment system 1 according to the embodiment of the present invention, the heat exchanger 10, the first heavy carbon separator 21, the second heavy carbon separator 22, And a heater 30, a recovery pump 40, a refrigerant supply device 50 and a solidification prevention device 60, and the configuration except for the solidification prevention device 60 may be collectively referred to as a reliquefaction device (not shown). Can be. Preferably, the reliquefaction apparatus may be represented on behalf of the heat exchanger 10.

Hereinafter, with reference to Figures 1 and 2 will be described with respect to the marine suspended matter comprising the gas treatment system 1 according to an embodiment of the present invention.

Prior to describing the individual configurations of the gas treatment system 1 according to the embodiment of the present invention, basic flow paths for organically connecting the individual components will be described. Here, the flow path may be a line through which the fluid flows, but is not limited thereto, and any flow path may be used.

In an embodiment of the present invention, the first to sixth lines L1 to L6 may be further included. Each line may be provided with valves (not shown) that can adjust the opening degree, and the supply amount of the boil-off gas or liquefied gas may be controlled by adjusting the opening degree of each valve.

The first line L1 connects the gas well with the first heavy carbon separator 21 and includes a heat exchanger 10, and a gas (for example, natural gas) is supplied from the gas well to the heat exchanger 10. Afterwards, the reliquefaction gas discharged from the heat exchanger 10 may be supplied to the first heavy carbon separator 21.

The second line L2 connects the first heavy carbon separator 21 and the heat exchanger 10, and may supply the gaseous phase separated from the first heavy carbon separator 21 to the heat exchanger 10. Here, the second line L2 may be formed with a first pressure sensor 631.

The third line L3 connects the heat exchanger 10 and the liquefied gas storage tank T, and supplies the liquefied gas produced by re-liquefying in the heat exchanger 10 to the liquefied gas storage tank T. have. In the third line L3, a second pressure sensor 632 may be formed.

The fourth line L4 connects the first heavy carbon separator 21 and the heavy carbon demand destination (not shown), and the second heavy carbon separator 22 and the heater 30 are disposed, and the first heavy carbon separator The liquid phase discharged from 21 may be supplied to the second heavy carbon separator 22.

The fifth line L5 connects the second heavy carbon separator 22 and the first heavy carbon separator 21, and converts the gas heavy carbon separated from the second heavy carbon separator 22 to the first heavy carbon separator ( 21).

The sixth line L6 is branched on the third line L3 to be connected to the first heavy carbon separator 21 and may include a recovery pump 40.

Hereinafter, individual components that are organically formed by the lines L1 to L6 described above to implement the gas treatment system 1 will be described.

Embodiments of the present invention may further include a preprocessor (not shown).

The preprocessor preprocesses the production gas produced from gas wells (not shown) located inland or on the seabed. In this case, the production gas may be natural gas in a gaseous state, and may be in a state containing a large amount of impurities.

Therefore, the preprocessor may be provided to remove impurities, and for example, mercury removal, moisture removal (drying), NGL removal, and the like may be performed. Of course, the configuration, role, etc. of the preprocessor may not be particularly limited. For example, the preprocessor may be omitted.

A first line L1 may be connected to the heat exchanger 10 to be described later via the pretreatment through the gas well, and the production gas flowing along the first line L1 is divided into liquefied gas and evaporated gas after liquefaction, respectively. Can be consumed.

However, in the present specification, the production gas may mean a gas produced directly in the gas well (W), but in addition, it may include all gas fuels that have to be treated and liquefied before being consumed in the gas demand (G). Let me know.

The liquefied gas storage tank T stores the liquefied gas. The liquefied gas storage tank (T) should store the liquefied gas in a liquid state, wherein the liquefied gas storage tank (T) may have a pressure tank form.

Here, the liquefied gas storage tank (T) is disposed inside the marine float, and may be formed as four, for example. The liquefied gas storage tank T is, for example, a membrane type tank, but is not limited thereto, and the type thereof is not particularly limited to various types such as a standalone tank.

In addition, the liquefied gas storage tank (T), in addition to being mounted on the marine float itself may be a space that can be stored to liquefy the production gas in a configuration that may be provided in the vicinity of the outside.

The liquefied gas storage tank (T) may vary in size or number depending on the size of the gas well, the amount of production gas, and the like, and the specifications of the liquefied gas storage tank (T) may not be particularly limited.

The liquefied gas stored in the liquefied gas storage tank (T) may be discharged to the outside when necessary and transported by a gas carrier or supplied to an external gas consuming facility.

The liquefied gas storage tank T may be connected to the heat exchanger 10 by the first line L1.

The heat exchanger 10 heat-exchanges the refrigerant supplied from the refrigerant supply device 50 and the gas supplied from the gas well (for example, NG; Natural Gas) to at least partially reliquefy the gas.

Specifically, the heat exchanger 10 is provided on the first line L1 to receive gas from the first line L1 and to receive the refrigerant from the refrigerant supply device 50 through a refrigerant circulation line (not shown). When supplied, the gas and the refrigerant are heat-exchanged, and the gas is at least partially reliquefied by the refrigerant to produce an intermediate reliquefaction gas.

The intermediate reliquefaction gas is supplied to the first heavy carbon separator 21 to separate the heavy carbon into the liquid phase, and the separated gas phase is supplied to the heat exchanger 10 through the second line L2 again. The heat exchanges with the refrigerant again to at least partially reliquefy to generate a reliquefied gas, and the reliquefied gas is supplied to the liquefied gas storage tank T through the third line L3.

The first heavy carbon separator 21 separates the intermediate reliquefaction gas discharged from the heat exchanger 10 into a gaseous phase and a liquid phase, and the separated gaseous phase is supplied to the heat exchanger 10 again. Can be supplied to heavy carbon customers.

Specifically, the first heavy carbon separator 21 is connected to the heat exchanger 10 through the first line L1 and the second line L2, and is connected to the heavy carbon demand destination through the fourth line L4. . In this case, the first heavy carbon separator 21 may have a first line L1 connected to the center, a second line L2 connected to the top, and a fourth line L4 connected to the bottom.

The first heavy carbon separator 21 may be supplied with an intermediate reliquefaction gas discharged from the heat exchanger 10 to separate the heavy carbon by separating the gas into a gas phase and a liquid phase. The heavy carbon may be separated into a liquid form and supplied to the heavy carbon demand destination through the fourth line L4 or supplied to the second heavy carbon separator 22 to be filtered again.

The second heavy carbon separator 22 is formed between the downstream of the heater 30 and the heavy carbon demand destination, and receives a liquid, that is, heated carbon, heated from the heater 30 to separate the gas heavy carbon and the liquid heavy carbon, and the gas Heavy carbon can be supplied back to the first heavy carbon separator 21 and liquid heavy carbon can be supplied to heavy carbon demand.

Specifically, the second heavy carbon separator 22 is formed between the downstream of the heater 30 on the fourth line L4 and the upstream of the heavy carbon demand destination. In this case, the second heavy carbon separator 21 may be connected such that the fourth line L4 enters from the center portion and exits from the bottom portion, and the fifth line L5 may be connected at the top portion.

The second heavy carbon separator 22 is supplied with a liquid heavy carbon discharged from the first heavy carbon separator 21 to be separated into a gas heavy carbon and a liquid heavy carbon to separate the heavy carbon more densely. The dense liquid heavy carbon is separated into a liquid form and supplied to the heavy carbon demand through the fourth line (L4). The gas heavy carbon has a higher density of C1 elements and the first heavy carbon separator (22). Can be supplied.

Heavy carbon separator in the present invention, in addition to the first and second heavy carbon separator 22 described above can be installed in plural more according to the requirements of the heavy carbon component of the heavy carbon demand destination, the cryogenic fraction column (Cryogenic Fraction Column) Can be formed.

The heater 30 may be formed downstream of the first heavy carbon separator 21 to heat the heavy carbon.

The heater 30 is formed between the second heavy carbon separator 22 and the first heavy carbon separator 21 on the fourth line L4 to supply the heavy carbon supplied from the first heavy carbon separator 21. After receiving and heating, it can be supplied to the second heavy carbon separator 22.

The heater 30 may be connected to the control unit 61 by wire or wirelessly, and may increase the heating degree of the heavy carbon supplied from the first heavy carbon separator 21 by receiving the operation instruction of the control unit 61. Through this, the gas heavy carbon in the second heavy carbon separator 22 may have more C1 elements, and the gas heavy carbon is further heated in the first heavy carbon separator 21 to the heat exchanger 10. Since it is supplied again, it is possible to further increase the output of liquefied gas (eg, LNG) and to produce high-quality liquefied gas.

The recovery pump 40 may be provided on the sixth line L6 to supply the reliquefaction gas to the first heavy carbon separator 21.

The recovery pump 40 is connected to the control unit 61 in a wired or wireless manner, receives an operation instruction from the control unit 61, and supplies the reliquefied gas discharged from the heat exchanger 10 to the first heavy carbon separator 21 again. You can.

In this case, the recovery pump 40 may be operated only when the supply of gas is stopped due to a decrease in reliquefaction performance due to a solidification phenomenon in the heat exchanger 10 or an operation problem. This has the effect of preventing the low-quality liquefied gas is stored in the liquefied gas storage tank (T).

The coolant supply device 50 may supply the coolant to the heat exchanger 10 so that the coolant heat exchanges with the gas.

The refrigerant supply device 50 is, for example, a variety of refrigerants such as glycol water, liquid nitrogen, and propane to cool the production gas below the boiling point of the production gas (about -163 degrees Celsius at 1 bar) when the production gas is natural gas. It may utilize, and the type of refrigerant in the present specification is not particularly limited.

The refrigerant supply device 50 may include a refrigerant gas liquid separator B, a refrigerant cooler H, a refrigerant expander E, a refrigerant circulation line, and a refrigerant compressor 501.

The refrigerant supply device 50 includes a refrigerant compressor 501 for compressing a refrigerant, a refrigerant cooler H for cooling the compressed refrigerant, and a refrigerant expander E for further cooling (Jul-Thomson effect) by reducing pressure; Or a refrigerant pressure reducer), and a refrigerant gas-liquid separator B for temporarily storing the refrigerant or replenishing the refrigerant. In addition, a refrigerant circulation line for connecting the configuration of the refrigerant compressor 501 or the like in a closed-loop form to implement the circulation of the refrigerant may be provided.

However, if only the low temperature refrigerant can be supplied to the refrigerant supply device 50, the components for supply or flow of the refrigerant may be provided differently from the above. That is, the refrigerant supply device 50 is connected to the heat exchanger 10 through the refrigerant circulation line, and the refrigerant gas-liquid separator B, the refrigerant cooler H, the refrigerant expander E, and disposed on the refrigerant circulation line. Arrangement of the refrigerant compressor 501 may be variously arranged as shown in FIG. 2 in addition to FIG. 1, and may be circulated while being compressed and expanded to be supplied to the heat exchanger 10 to exchange gas and cold heat.

The refrigerant compressor 501 may compress the refrigerant and supply the refrigerant to the heat exchanger 10 through the refrigerant circulation line from the refrigerant supply device 50.

The refrigerant compressor 501 is connected to the control unit 61 in a wired or wireless manner, thereby increasing the flow rate of the refrigerant supplied to the heat exchanger 10 by increasing the degree of compression of the refrigerant according to the operation instruction of the control unit 61. have.

The gas treatment system 1 of the present invention may, for example, follow an LNG liquefaction process. The gas treatment system 1 of the present invention has a problem in that the LNG liquefaction process is interrupted when the heat exchanger 10 for liquefying the gas with the refrigerant supplied by the refrigerant compressor 501 is broken and the loss is very large. have.

Specifically, in the heat exchanger 10, when an aromatic chemical substance (Benzene) is solidified in an internal flow path, the heat transfer area of the heat exchanger 10 may be reduced, thereby degrading LNG liquefaction performance. The flow path inside the heat exchanger 10 may be clogged.

In this case, maintenance of the heat exchanger 10 is performed, which means that the LNG liquefaction process is stopped, and thus, the production of LNG is impossible during the maintenance period, and a stabilization period required for driving the LNG liquefaction process is required for a considerable period of time. Therefore, the loss is a very big problem.

Accordingly, the gas treatment system 1 of the present invention has been solved by establishing a solidification prevention device 60 in order to prevent the chemical solidification phenomenon of the aromatic series (Benzene) in the heat exchanger (10).

The solidification prevention device 60 calculates a difference value between the pressure of the gas flowing into the heat exchanger 10 and the pressure of the gas flowing out of the heat exchanger 10, and the heater 30, the refrigerant supply device 50, and the like. The driving of the reliquefaction apparatus is controlled to prevent the solidification phenomenon occurring inside the heat exchanger 10.

The solidification prevention device 60 may include a controller 61, a calculator 62, and first and second pressure sensors 631 and 632.

The control unit 61 receives the difference value calculated by the calculation unit 62 by wire or wirelessly, and drives the reliquefaction apparatus, that is, the heater 30 and the refrigerant supply device 50 according to the received difference value. It can be controlled to stop the inflow or outflow of gas.

Specifically, when the difference value is greater than the first preset difference value, the controller 61 increases the flow rate of the refrigerant supplied from the refrigerant supply device 50 to the heat exchanger 10 so as to be larger than the preset flow rate, and the difference value. When it becomes larger than the 2nd predetermined difference value larger than this 1st predetermined difference value, it will control to stop supply of the gas supplied to the heat exchanger 10, and to operate the recovery pump 40, and a difference value will be set to the 1st predetermined value. When the temperature is smaller than the third preset difference value smaller than the difference value, the heating degree of the heater 30 may be controlled to be increased than the preset heating degree.

More specifically, the control unit 61 controls the operation degree of the refrigerant compressor 501 to operate higher than the preset compressor operation degree when the difference value calculated by the calculation unit 62 becomes greater than the first preset difference value. When the flow rate of the refrigerant supplied from the supply device 50 to the heat exchanger 10 is increased to be greater than the preset flow rate, and the difference value is greater than the second preset difference value, supply of the gas supplied to the heat exchanger 10. Stop and operate the recovery pump 40 to control the reliquefaction gas to be supplied to the first heavy carbon separator 21 through the sixth line L6, and when the difference value is smaller than the third preset difference value, the heater The heating degree of 30 can be increased to be higher than the preset heating degree to increase the generation of gas heavy carbon and to recover the gas heavy carbon back to the first heavy carbon separator 21 through the fifth line L5. have.

The calculation unit 62 calculates a difference between the pressure of the gas flowing into the heat exchanger 10 and the pressure of the reliquefied gas discharged after being liquefied by the heat exchanger 10, and wires the difference value to the control unit 61. Or wirelessly.

Specifically, the calculator 62 receives the first pressure value, which is the pressure of the gaseous phase supplied from the first heavy carbon separator 21 to the heat exchanger 10, through the first pressure sensor 631, and the heat exchanger. After receiving the second pressure value, which is the pressure of the reliquefied gas discharged from (10), through the second pressure sensor 632, calculates the difference between the pressure between the first pressure value and the second pressure value, the calculated difference value It can be delivered to the control unit 61 by wire or wireless.

The first pressure sensor 631 measures the first pressure value, which is the pressure of the gaseous phase formed on the second line L2 and supplied to the heat exchanger 10, and calculates the measured first pressure value 62. Can be delivered via wired or wireless.

The second pressure sensor 632 is formed on the third line (L3) to measure the second pressure value that is the pressure of the reliquefied gas discharged from the heat exchanger 10, and calculates the measured second pressure value And can be delivered via wired or wireless.

Therefore, in the present invention, by measuring the pressure difference between the inlet and outlet of the heat exchanger 10 through the solidification prevention device 60, it is easy to know whether the solidification occurs inside the heat exchanger 10, and only the detection of the solidification occurrence However, it is possible to predict the occurrence of solidification, thereby improving the driving reliability of the gas treatment system 1.

In addition, in the present invention, the solidification prevention device 60 increases the amount of refrigerant flowing into the heat exchanger 10 by increasing the driving amount of the refrigerant compressor 501 when a solidification occurrence in the heat exchanger 10 is predicted through the control unit 61. It is effective to prevent the occurrence of coagulation in advance.

In addition, in the present invention, it is possible to predict that the solidification incidence decreases as well as the instant of solidification occurrence through the solidification prevention device 60, so that when the solidification incidence decreases, the heater 30 is operated to contain elements of the C1 series. It is possible to increase the output of liquefied gas by producing a large amount of heavy carbon.

As described above, the gas treatment system 1 according to the present invention and the marine suspended matter including the same may fix the fluid flowing in the heat exchanger 10 through a numerical value of the pressure difference between the inlet and the outlet of the heat exchanger 10. The phenomenon can be prevented, thus reducing the operating cost of the system and improving the operation reliability.

3 is a conceptual diagram of a gas treatment system according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the gas treatment system 1 according to the embodiment of the present invention includes a heat exchanger 10, a gas-liquid separator 20, a refrigerant supply device 50, an anti-surge control unit 70, and evaporation. And a gas compressor 80, a temperature regulating device 90 and a demand source flow rate control unit 91, and an anti-surge control unit 70, an evaporative gas compressor 80, a temperature regulator 90 and a demand source supply flow rate control unit ( The configuration other than 91 may be collectively referred to as a reliquefaction apparatus (not shown). Preferably, the reliquefaction apparatus may be represented on behalf of the heat exchanger 10.

In the present embodiment, the heat exchanger 10 and the refrigerant supply device 50 are the same as or similar to the heat exchanger 10 and the refrigerant supply device 50 in the previous embodiment, so that the heat exchanger 10 and the refrigerant supply device 50 are replaced with the same. Reference numerals are used, but are not necessarily referring to the same configuration.

Hereinafter, a gas treatment system 1 according to an exemplary embodiment of the present invention will be described with reference to FIG. 3.

Prior to describing the individual configurations of the gas treatment system 1 according to the embodiment of the present invention, basic flow paths for organically connecting the individual components will be described. Here, the flow path may be a line through which the fluid flows, but is not limited thereto, and any flow path may be used.

In the embodiment of the present invention, the re-liquefaction supply line (R1), gas supply line (R2), liquefied gas recovery line (R3) may further include a temperature control line (R4). Each line may be provided with valves (not shown) that can adjust the opening degree, and the supply amount of the boil-off gas or liquefied gas may be controlled by adjusting the opening degree of each valve.

The reliquefaction supply line R1 connects the gas well and the gas-liquid separator 20 and includes a heat exchanger 10 and an auxiliary surge protection device 72. The gas (for example, natural gas) is heat exchanged in the gas well. After being supplied to the gas 10, the reliquefaction gas discharged from the heat exchanger 10 may be supplied to the gas-liquid separator 20.

The gas supply line R2 connects the gas-liquid separator 20 and the gas demand destination G, and includes an evaporative gas compressor 80, a scrubber 81, and a flow rate measuring sensor 713, in the gas-liquid separator 20. The separated gaseous gas may be pressurized through the evaporative gas compressor 80 and supplied to the gas demand G.

The liquefied gas recovery line R3 connects the gas-liquid separator 20 and the liquefied gas storage tank T, and converts the liquefied gas (eg, LNG) produced as a liquid gas separated from the gas-liquid separator 20 to the liquefied gas. It can be supplied to the storage tank (T).

The temperature control line R4 is connected to the scrubber 81 which is branched on the liquefied gas recovery line R3 and disposed upstream of the boil-off gas compressor 80, and which supplies the gaseous gas supplied to the boil-off gas compressor 80. In order to control the temperature, the liquefied gas flowing on the liquefied gas recovery line R3 may be supplied to the scrubber 81.

Hereinafter, individual components which are organically formed by the lines R1 to R4 described above to implement the gas treatment system 1 will be described.

The gas demand destination G consumes gaseous gas generated when producing liquefied gas in the gas treatment system 1 of the present invention, and may be, for example, a consumer such as a power generation engine or a boiler.

The gas demand unit G may pressurize and supply the gaseous gas separated from the at least partially reliquefied gas in the heat exchanger 10 through the boil-off gas compressor 80, and consume the gas supply line R2. It can be connected to the gas-liquid separator 20 through.

The gas-liquid separator 20 receives at least a part of the reliquefied gas from the heat exchanger 10 (also referred to as a reliquefaction apparatus) and separates the gas into a gaseous phase and a liquid phase to supply gaseous gas to the evaporative gas compressor 80 to supply fuel. The liquid gas may be produced as a liquefied gas and supplied to the liquefied gas storage tank T, or supplied to the scrubber 81 disposed upstream of the boil-off gas compressor 80.

Specifically, the gas-liquid separator 20 is connected to the heat exchanger 10 through the reliquefaction supply line R1 and connected to the gas demand destination G through the gas supply line R2, and connects the liquefied gas recovery line R3. Can be connected to the liquefied gas storage tank (T) through.

The anti-surge control unit 70 prevents the occurrence of surge in the boil-off gas compressor 80, and is connected to the main surge protection device 71 and the auxiliary surge protection device 72 by wire or wirelessly to prevent the surge from occurring. Through the 71 and the auxiliary surge prevention device 72, the surge phenomenon of the boil-off gas compressor 80 can be prevented.

The anti-surge control unit 70 controls the main surge protection device 71 to be driven preferentially, and the secondary surge protection device 72 is subsidiaryly assisted when the response of the main surge protection device 71 is slow or a failure occurs. Can be controlled to be driven.

Alternatively, the surge prevention control unit 70 controls the auxiliary surge protection device 72 to operate first so that an excessive amount of gaseous gas is always supplied to the boil-off gas compressor 80 to prevent the surge from occurring in the boil-off gas compressor 80. It can be prevented beforehand.

The main surge prevention device 71 is configured to connect the upstream and downstream of the boil-off gas compressor 80, and when the surge of the boil-off gas compressor 80 generates a surge, the boil-off gas discharged downstream of the boil-off gas compressor again returns to the boil-off gas compressor ( Surge can be prevented by supplying upstream of 80).

The main surge prevention device 71 includes a bypass line 711 connecting upstream and downstream of the boil-off gas compressor 80, a bypass valve 712 and a gas supply line formed on the bypass line 711. It may include a flow rate measuring sensor 713 disposed downstream of the boil-off gas compressor 80 on R2).

The main surge prevention device 71 may predict or measure the occurrence of the surge phenomenon of the boil-off gas compressor 80 through the flow rate information measured by the flow rate measuring sensor 713, and when the surge of the boil-off gas compressor 80 occurs. The opening degree of the bypass valve 712 may be opened to supply the boil-off gas discharged downstream of the boil-off gas compressor back upstream of the boil-off gas compressor 80. The control of the main surge protection device 71 may be made by the surge protection controller 70.

The auxiliary surge prevention device 72 prevents surge of the boil-off gas compressor 80, and when a surge occurs in the boil-off gas compressor 80, at least partly reliquefaction discharged from the heat exchanger 10. At least a part of the vaporized gas is increased to increase the flow rate of gaseous gas supplied to the boil-off gas compressor 80.

Specifically, the auxiliary surge prevention device 72 is formed of an electric heater and is disposed between the heat exchanger 10 and the gas-liquid separator 20 on the reliquefaction supply line R1, and the heat exchanger 10 At least a part of the re-liquefied gas discharged may be supplied to the gas-liquid separator 20 by at least a part of vaporized gas to increase the flow rate of gaseous gas separated in the gas-liquid separator 20.

More specifically, the auxiliary surge protection device 72 is discharged from the heat exchanger 10 when the main surge protection device 71 is delayed or stopped due to a failure when a surge occurs in the boil-off gas compressor 80. It is operated to vaporize at least some of the re-liquefied gas, which can increase the amount of gas generated in the gaseous phase gas generated in the gas-liquid separator 20 to increase the amount of gas in the gas phase supplied to the evaporative gas compressor (80).

The anti-surge control unit 70, in addition to the function of preventing the occurrence of surge in the boil-off gas compressor 80, the cryogenic stress change that may occur in the mechanical equipment such as the gas-liquid separator 20 during the start operation of the reliquefaction apparatus (Thermal) It can have a function to prevent the occurrence of shock.

The anti-surge control unit 70 is connected to the auxiliary surge protection device 72 in a wired or wireless manner so that the auxiliary surge protection device 72 is at least partially reliquefied gas from the heat exchanger 10 to the gas-liquid separator 20. By controlling to be driven when starting to be supplied, the temperature of at least some of the reliquefied gas supplied to the gas-liquid separator 20 can be raised by heating at least some of the reliquefied gas.

Through this, in the present invention, it is possible to flexibly cope with the cryogenic stress change (Thermal Shock) that may occur in the mechanical equipment such as gas-liquid separator 20 during the start-up operation of the reliquefaction apparatus through the operation of the auxiliary surge protection device 72 It works.

The surge prevention control unit 70 may have a function of controlling the temperature of the gas in the gaseous phase supplied to the boil-off gas compressor 80 in addition to the function of preventing surge generation of the boil-off gas compressor 80.

The anti-surge control unit 70 is connected to the temperature control device 90 in a wired or wireless manner, so as to lower the temperature of the gaseous gas supplied to the boil-off gas compressor 80, the valve formed in the temperature control device 90 is provided. It can be controlled to open and supply the liquefied gas of the liquid phase separated from the gas-liquid separator 20 to the scrubber 81.

This will be described in detail in the thermostat (90).

The boil-off gas compressor 80 compresses the gaseous gas supplied from the gas-liquid separator 20 and supplies it to the gas demand destination G, and may include a scrubber 81 upstream and a cooler (not shown) downstream. It may be provided.

The boil-off gas compressor 80 may adjust the degree of compression of the boil-off gas according to the required pressure of the gas demand destination G, which is controlled by adjusting the operating load of a motor (not shown) provided in the boil-off gas compressor 80. Can be done.

For example, the boil-off gas compressor 80 may compress the boil-off gas to around 10 bar when the gas demand source G is a power generation engine, or the boil-off gas 10 bar to 400 bar when the gas demand G is ME-GI or XDF. Or the like. That is, the discharge pressure of the boil-off gas compressor 80 may vary depending on the gas demand G, and thus is not particularly limited.

In order for the boil-off compressor 80 to operate smoothly, the boil-off gas above a certain minimum flow rate must be introduced. When the flow rate flowing into the boil-off gas compressor 80 is excessively reduced, there is a possibility that a surge that causes the boil-off gas compressor 80 to become unstable may occur.

Accordingly, the present invention provides surge protection devices 71 for returning the boil-off gas downstream of the boil-off gas compressor 80 upstream of the boil-off gas compressor 80 (eg, upstream of the scrubber 81 or inside the scrubber 81). 72, which will be replaced with the above-described bar in detail.

In the gas supply line R2 connected from the boil-off gas compressor 80 to the gas demand destination G, a shutdown valve (not shown) is provided. The shutdown valve is shut off when a problem occurs in the front end of the gas demand (G) or the gas demand (G) and fails to consume the evaporated gas discharged from the boil-off gas compressor (80). Is not supplied.

When the shutdown valve is closed, the boil-off gas discharged from the boil-off gas compressor 80 may be discharged to the outside through a relief line (not shown) branched from the gas supply line R2. A relief valve (not shown) may be provided in the relief line, and the relief valve may be configured to open when a predetermined pressure or more is detected.

When the shutdown valve is closed, the boil-off gas discharged from the boil-off gas compressor 80 cannot flow, and the pressure downstream of the boil-off gas compressor 80 increases. When the pressure rises above a certain level, the relief valve opens and the boil-off gas is released. It can be discharged to the outside through. At this time, the outside may mean atmosphere, or may be a vent mast, a combustion device, or a separate demand destination.

The scrubber 81 is formed upstream of the boil-off gas compressor 80 on the gas supply line R2, and can remove impurities or liquids of gaseous gas supplied to the boil-off gas compressor 80, and the boil-off gas compressor ( The temperature of the gas in the gas phase supplied to the 80 can be adjusted.

The scrubber 81 may have a function of gas-liquid separation similarly or similarly to the gas-liquid separator 20, and thus, only the vaporized gaseous gas may flow into the evaporative gas compressor 80 provided downstream of the scrubber 81. Can be.

The scrubber 81 is a vaporized gas discharged from the gas-liquid separator 20 is introduced, but the liquid droplets can be mixed, the liquid droplets that can be separated in the scrubber 81 is liquefied as in the gas-liquid separator 20 It may be delivered to the gas storage tank (T).

Alternatively, the scrubber 81 may be vaporized in the scrubber 81 even if the droplets are mixed so that the boil-off gas may be supplied to the boil-off gas compressor 80 in an intact gas state, in which case the scrubber 81 liquefied gas. The storage tank (T) may not be provided with a separate recovery line.

However, since the droplets separated from the scrubber 81 may be condensate, which lowers the efficiency of the gas demand G, the scrubber 81 has a condensate discharge line (not shown), so that the condensate is an evaporative gas compressor. It can be collected into a condensate tank (not shown) connected along the condensate discharge line without entering the 80.

In this case, the condensate collected in the condensate tank may be a material having a calorific value, so that it may be consumed in a separate demand source such as an engine or a boiler or burned by a combustion device, or may be stored and then delivered to the land for processing.

The scrubber 81 can suppress fluctuations in the flow rate of the boil-off gas compressor 80 while temporarily storing the boil-off gas supplied to the boil-off gas compressor 80. That is, the scrubber 81 may serve as a drum / damper, and thus the inflow of the boil-off gas compressor 80 may be maintained relatively constant.

In addition, the scrubber 81 is such that the amount of inflow of the boil-off gas flowing into the boil-off gas compressor 80 is greater than or equal to a minimum flow rate such that there is no problem in the operation of the boil-off gas compressor 80, thereby operating efficiency of the boil-off gas compressor 80. Can be guaranteed.

The cooler is provided downstream of the boil-off gas compressor 80 and cools the boil-off gas compressed in the boil-off gas compressor 80. As the boil-off gas is compressed in the boil-off gas compressor 80, the temperature may rise with the pressure rise. The cooler uses the refrigerant to cool the boil-off gas so that the heated boil-off gas can be adapted to the required temperature of the gas demand destination G. can do.

In addition, the cooler may prevent the temperature of the boil-off gas from rising by continuous compression while the boil-off gas downstream of the boil-off gas compressor 80 flows back into the boil-off gas compressor 80 to prevent surge.

That is, the cooler allows the high temperature / high pressure evaporated gas discharged from the evaporative gas compressor 80 to cool down and then flows back into the evaporative gas compressor 80 through the scrubber 81, thereby circulating the evaporated gas to prevent surge. It can suppress that temperature of the circulating boil-off gas rises too much.

The cooler may use a coolant that is the same as or similar to the coolant described in the coolant supply device 50. At this time, the cooler may have a heat exchanger form or a drum form, but the structure in which the cooler cools the boil-off gas is not particularly limited.

Temperature controller 90 is provided on the temperature control line (R4) may have the form of a valve, for example, the gas-liquid separator 20 to control the temperature of the gas of the gas supplied to the boil-off compressor (80) The liquid liquefied gas separated in) can be supplied to the scrubber 81.

Temperature control device 90 is connected to the anti-surge control unit 70 in a wired or wireless manner can receive the opening and closing instructions of the valve, the valve to lower the temperature of the gas gas supplied to the boil-off gas compressor 80 Open to supply the liquefied gas of the liquid separated in the gas-liquid separator 20 to the scrubber (81).

The demand destination supply flow rate control unit 91 vaporizes the gas supplied to the evaporative gas compressor 80 by vaporizing at least a part of the reliquefied gas discharged from the heat exchanger 10 when the amount of gas required by the gas demand destination G is insufficient. It is possible to increase the flow rate of the gas.

The supply source supply flow control unit 91 is connected to the gas demand source (G), the boil-off gas compressor (80) and the auxiliary surge protection device (72) by wire or wirelessly, and when the gas demand required by the gas demand source (G) is insufficient, the auxiliary surge The prevention device 72 is operated to increase the amount of vaporization of at least some of the reliquefied gas discharged from the heat exchanger 10 and thereby increase the flow rate of gaseous gas supplied to the boil-off gas compressor 80, At the same time, by controlling to increase the driving degree of the boil-off gas compressor 80, it is possible to increase the flow rate of the gas in the gas phase supplied to the gas demand (G).

Through this, the present invention has the effect of ensuring a sufficient fuel supply to the gas demand (G) and the effect of improving the reliability of system operation.

As described above, the gas treatment system 1 according to the present invention and the marine float comprising the same include an electric heater 72 upstream of the boil-off gas compressor 80, so that a surge risk occurs when the boil-off gas is generated. By increasing the amount of gas flowing into the) can prevent the occurrence of surge has the effect of improving the operation reliability and stable system implementation.

In addition, the gas treatment system 1 according to the present invention and the marine float including the same, by placing the electric heater 72 upstream of the boil-off gas compressor (80), when the gas demand destination (G) fuel shortage of the boil-off gas compressor ( 80 can increase the amount of gas flowing into the gas supply (G) has the effect of ensuring a sufficient supply of fuel and the effect of improving the system operation is effective.

In addition, the gas treatment system 1 and the marine float including the same according to the present invention, by placing the electric heater 72 upstream of the gas-liquid separator 20 for separating the re-liquefied gas into the gas phase and liquid phase at the time of initial system operation The cryogenic stress change (Thermal shock) of the gas-liquid separator 20 can be prevented, thereby improving the durability of the system.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and should be understood by those skilled in the art within the technical spirit of the present invention. It is obvious that the modifications and improvements are possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

1: gas treatment system
10: heat exchanger 20: gas-liquid separator
21: First Heavy Carbon Separator 22: Second Heavy Carbon Separator
30: heater 40: recovery pump
50: refrigerant supply device 501: refrigerant compressor
60: solidification prevention device 61: control unit
62: calculator 631: first pressure sensor
632: second pressure sensor 70: surge prevention control unit
71: main surge protector 711: bypass line
712: bypass valve 713: flow measurement sensor
72: auxiliary surge protection device 80: boil-off gas compressor
81: scrubber 90: temperature controller
91: demand flow rate control unit
L1 to L6: first to sixth lines R1: reliquefaction supply line
R2: Gas Supply Line R3: Liquefied Gas Recovery Line
R4: temperature control line
T: liquefied gas storage tank B: refrigerant gas liquid separator
H: Refrigerant cooler E: Refrigerant expander
G: gas demand

Claims (11)

A reliquefaction apparatus for liquefying the gas by exchanging a refrigerant and a gas;
The at least partly reliquefied gas is supplied from the reliquefaction apparatus to be separated into a gaseous phase and a liquid phase, and the gaseous gas is supplied to an evaporative gas compressor to be used as a fuel, and the liquid gas is produced as a liquefied gas. A gas-liquid separator supplied to the storage tank; And
It includes a surge prevention device for preventing the generation of surge (surge) of the boil-off gas compressor,
The surge prevention device,
When a surge occurs in the boil-off gas compressor, at least a part of the re-liquefied gas discharged from the re-liquefaction apparatus is vaporized to increase the flow rate of the gaseous gas supplied to the boil-off gas compressor. Processing system. The method of claim 1,
The anti-surge device is formed of an electric heater and is disposed between the reliquefaction apparatus and the gas-liquid separator, thereby at least partially vaporizing the at least partially reliquefied gas discharged from the reliquefaction apparatus to supply the gas-liquid separator. And increasing the flow rate of the gas in the gas phase separated in the gas-liquid separator. According to claim 2, The surge protection device,
When at least some of the reliquefied gas starts to be supplied to the gas-liquid separator in the reliquefaction apparatus, the temperature of the at least partially reliquefied gas supplied to the gas-liquid separator is driven by heating the at least partially reliquefied gas. Gas treatment system, characterized in that the raising. The method of claim 2,
Further comprising a gas demand destination for receiving the compressed gas supplied from the boil-off gas compressor,
The surge prevention device,
When the amount of gas required by the gas demand destination is insufficient, at least a part of the reliquefied gas discharged from the reliquefaction apparatus to at least partially vaporize the gas, characterized in that for increasing the flow rate of the gas gas supplied to the boil-off gas compressor Processing system. The method of claim 4, wherein
A reliquefaction supply line connecting the reliquefaction apparatus and the gas-liquid separator, the reliquefaction supply line including the surge prevention device; And
And a gas supply line connecting the gas-liquid separator and the gas demand destination. The method of claim 1,
Liquefied gas storage tank for storing the liquefied gas; And
Further comprising a scrubber provided upstream of the boil-off compressor,
The gas-liquid separator,
And supply the liquefied gas to the liquefied gas storage tank or to the scrubber. The gas-liquid separator of claim 6,
And the liquefied gas is supplied to the scrubber in order to adjust the temperature of gaseous gas supplied to the boil-off gas compressor. The method of claim 7, wherein
A reliquefaction supply line connecting the reliquefaction apparatus and the gas-liquid separator, the reliquefaction supply line including the surge prevention device;
A gas supply line connecting the gas-liquid separator and the gas demand destination;
A liquefied gas recovery line connecting the gas-liquid separator and the liquefied gas storage tank; And
And a temperature control line connecting the gas-liquid separator and the scrubber. The method of claim 1,
And a main surge prevention device configured to connect the upstream and downstream of the boil-off gas compressor, and supply the boil-off gas discharged downstream of the boil-off gas compressor back upstream of the boil-off gas compressor when a surge occurs in the boil-off gas compressor. and,
The surge suppression device is an auxiliary surge suppression device, and operates in cooperation with the main surge suppression device. The method of claim 9, wherein the main surge protection device,
A bypass line configured to connect the upstream and downstream of the boil-off gas compressor; And
And a bypass valve formed on said bypass line. A marine float comprising the gas treatment system of any of claims 1 to 10.

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