阅读说明：本技术 一种气相共管的安全防护系统及方法 (Gas-phase co-pipe safety protection system and method ) 是由 蒋春辉 于 2019-10-16 设计创作，主要内容包括：本发明提供了一种气相共管的安全防护系统及方法,包括：LNG存储系统,所述LNG存储系统包括至少十组罐箱系统,所述罐箱系统包括存贮有LNG的LNG罐箱；主管路系统,所述主管路系统包括主介质管路；安全监控与控制系统,所述安全监控与控制系统包括控制器、第一压力传感器和第二压力传感器；所述控制器用于接收所述第一压力传感器和所述第二压力传感器发送的压力值数据并控制所述报警器的开启与关闭。这种气相共管的安全防护系统当某个LNG罐箱中的压力值大于预设值(如0.5 MPa)之后,报警器提示工作人员将该LNG罐箱与主介质管路接通,实现了气相共管。(The invention provides a gas-phase common-pipe safety protection system and a gas-phase common-pipe safety protection method, wherein the gas-phase common-pipe safety protection system comprises the following steps: an LNG storage system comprising at least ten sets of tank systems, the tank systems comprising LNG tanks storing LNG; a main piping system comprising a main media piping; the safety monitoring and control system comprises a controller, a first pressure sensor and a second pressure sensor; the controller is used for receiving the pressure value data sent by the first pressure sensor and the second pressure sensor and controlling the alarm to be turned on and off. After the pressure value in a certain LNG tank is larger than a preset value (such as 0.5 MPa), the alarm prompts a worker to connect the LNG tank with the main medium pipeline, so that gas-phase common management is realized.)

1. A gas phase co-fired safety shield system, comprising:

an LNG storage system (1), the LNG storage system (1) comprising at least ten sets of tank systems, the tank systems comprising LNG tanks (101) storing LNG; the first female joint (102) is connected with a BOG gas phase space inside the LNG tank (101) through a first connecting pipe (103); an alarm (404) is arranged on the LNG tank (101); a first manual stop valve (104) is mounted on the first connecting pipe (103);

a main pipeline system (6), wherein the main pipeline system (6) comprises a main medium pipeline (601) and a plurality of first male connectors (602) matched with the first female connectors (102), and each first male connector (602) is connected with the main medium pipeline (601) through a second connecting hose (603); when the first female connector (102) is inserted into the first male connector (602), the corresponding first connection pipe (103) and second connection hose (603) are connected;

a safety monitoring and control system (4), the safety monitoring and control system (4) comprising a controller (403), a first pressure sensor (401) and a second pressure sensor (402);

the first pressure sensor (401) is used for detecting the pressure value of the BOG gas phase space in the LNG tank (101); the second pressure sensor (402) is used for detecting the pressure value of BOG in the main medium pipeline (601);

the controller (403) is used for receiving pressure value data sent by the first pressure sensor (401) and the second pressure sensor (402) and controlling the alarm (404) to be turned on and off.

2. A gas phase co-pipe safety shield system as recited in claim 1, wherein:

the BOG reliquefaction recovery system (3) comprises a regenerative refrigerator (301), and the regenerative refrigerator (301) comprises a low-temperature heat exchanger (302); a second medium line (307) is connected between the inlet of the cryogenic heat exchanger (302) and the main medium line (601); the connection of the second medium line (307) to the main medium line (601) is located between the first end and the second end of the main medium line (601); and a second pneumatic regulating valve (305) is installed on the second medium pipeline (307), and the controller (403) controls the regenerative refrigerator (301) and the second pneumatic regulating valve (305) to be opened or closed.

3. A gas phase co-pipe safety shield system as recited in claim 2, wherein:

the BOG reliquefaction device is characterized by further comprising a reliquefaction BOG storage system, wherein the reliquefaction BOG storage system comprises a spray header (501) and a liquid storage tank (502), the spray header (501) is arranged in the liquid storage tank (502) and is positioned at the top of the liquid storage tank (502), and the spray header (501) is provided with an inlet extending out of the liquid storage tank (502); a third medium pipe (306) is connected between the inlet of the spray header (501) and the outlet of the low-temperature heat exchanger (302).

4. A gas phase co-pipe safety shield system as recited in claim 3, wherein:

the system also comprises a natural gas power system (2), wherein the natural gas power system (2) comprises a combustion system (201) and a cold recovery device (202); the combustion system (201) is used for combusting BOG to drive the gas turbine to operate; a first medium line (206) is connected between an inlet of the combustion system (201) and a first end of the main medium line (601); a first pneumatic regulating valve (604) is arranged on the main medium pipeline (601), and the first pneumatic regulating valve (604) is close to the first end part of the main medium pipeline (601); the controller (403) controls the opening or closing of the first pneumatic regulating valve (604);

the cold recovery device (202) is a heat exchanger with a plurality of inlets and a plurality of outlets, which are mounted via different inlets and outlets in a first medium line (206), an internal combustion turbine air line (203), a tank carrier cold air system line (204) and a gas turbine exhaust and recirculated cooling water line (205).

5. A gas phase co-pipe safety shield system as recited in claim 4, wherein:

the mast ignition system (7) comprises a safety valve (701), a mast exhaust pipe (702) and an igniter (703), the second end of the main medium pipeline (601) is connected to the inlet of the mast exhaust pipe (702), and the outlet of the mast exhaust pipe (702) is communicated with the outside; the igniter (703) is arranged at the outlet of the mast exhaust pipe (702); the safety valve (701) is arranged at a second end of the main medium line (601); the controller (403) controls ignition of the igniter (703).

6. A gas phase co-pipe safety shield system as recited in claim 5, wherein:

the safety monitoring and control system (4) further comprises a third pressure sensor (405), wherein the third pressure sensor (405) is used for detecting the pressure value of the BOG gas phase space inside the liquid storage tank (502);

a fourth medium pipeline (504) is connected with the BOG gas phase space inside the liquid storage pipe and the first medium pipeline (206); a third pneumatic regulating valve (503) is installed on the fourth medium pipeline (504);

the controller (403) controls the opening and closing of the third pneumatic regulating valve (503).

7. A gas phase co-pipe safety shield system as recited in claim 6, wherein:

the device also comprises a fifth medium pipeline (509), wherein the first end of the fifth medium pipeline (509) is connected with a liquid phase space in the liquid storage tank (502), the second end of the fifth medium pipeline is connected with a BOG gas phase space in the liquid storage tank (502), and at least one part of the fifth medium pipeline (509) is positioned outside the liquid storage tank (502);

a first pneumatic stop valve (506) and a self-pressurization heat exchange coil (505) are installed on the fifth medium pipeline (509), the first pneumatic stop valve (506) and the self-pressurization heat exchange coil (505) are both positioned outside the liquid storage tank (502), and the first pneumatic stop valve (506) is closer to a first end of the fifth medium pipeline (509) relative to the self-pressurization heat exchange coil (505);

a liquid outlet pipeline (507), wherein one end of the liquid outlet pipeline (507) is connected with a liquid phase space in the liquid storage tank (502), and a second pneumatic stop valve (508) is installed on the liquid outlet pipeline (507);

the safety monitoring and control system (4) further comprises a liquid level sensor (406), wherein the liquid level sensor (406) is used for detecting the liquid level height of the LNG in the liquid storage tank (502);

the safety monitoring and control system (4) is used for controlling the opening and closing of the first pneumatic stop valve (506) and the second pneumatic stop valve (508).

8. The gas-phase common pipe safety protection method based on the gas-phase common pipe safety protection system according to any one of claims 1 ~ 7, specifically comprising the following steps:

s1: when the first pressure sensor (401) detects that the pressure value of the BOG gas phase space in the LNG tank (101) is larger than a first preset value, the controller (403) controls the alarm (404) to be opened, the first male connector (602) and the first female connector (102) are manually inserted and closed, and a first manual stop valve (104) is opened; BOG in the LNG tank (101) enters the main medium pipeline (601);

s2: when the pressure value detected by the second pressure sensor (402) is larger than a second preset value, the controller (403) opens the second pneumatic regulating valve (305), and the BOG in the main medium pipeline (601) flows into the BOG reliquefaction and recovery system (3);

after the BOG flows into the BOG reliquefaction recovery system (3), the controller (403) opens the regenerative refrigerator (301) for refrigeration, and the BOG flows through the low-temperature heat exchanger (302) and is liquefied into LNG which is sprayed into the liquid storage tank (502) through the spray header (501);

s3: when the pressure value in the main medium pipeline (601) is larger than a fourth preset value, the safety valve (701) is automatically opened, and BOG in the main medium pipeline (601) flows into the mast ignition system (7);

after the BOG flows into the mast ignition system (7), the controller (403) controls the igniter (703) to be started, and the BOG at the outlet of the mast exhaust pipe (702) is ignited.

9. The method for safety protection of gas phase common pipe according to claim 8, wherein:

also included between S1 and S2 is S11: the controller (403) controls the first pneumatic regulating valve (604) to be opened, and BOG in the main medium pipeline (601) flows into the natural gas power system (2);

also included between S2 and S3 is S21: when the difference between the second pressure sensor (402) and the third pressure sensor (405) is smaller than a third predetermined value, the controller (403) controls the third pneumatic regulating valve (503) to be opened to introduce the BOG in the liquid storage tank (502) into the natural gas power system (2);

after BOG flows into the natural gas power system (2), the BOG exchanges heat through a cold energy recovery device (202) and then flows into the combustion system (201) to be combusted, so that a gas turbine is pushed to operate; in the refrigeration capacity recovery device (202), the BOG in the first medium pipe (206) exchanges heat with the internal combustion turbine air pipe (203), the tank carrier cold air system pipe (204), and the gas turbine exhaust gas and circulating cooling water pipe (205).

10. The method for safety protection of a gas phase common pipe according to claim 9, wherein:

after S3, further comprising S4: when the liquid level sensor (406) detects that the liquid level of the LNG in the liquid storage tank (502) reaches a fifth preset value, the controller (403) controls the regenerative refrigerator (301), the second pneumatic regulating valve (305) and the third pneumatic regulating valve (503) to be closed, and controls the first pneumatic stop valve (506) and the second pneumatic stop valve (508) to be opened; LNG in the liquid storage tank (502) flows out of the liquid storage tank (502) through a liquid outlet pipeline (507) to be stored for a long time.

Technical Field

The invention relates to the field of BOG protection systems, in particular to a gas-phase co-pipe safety protection system and a gas-phase co-pipe safety protection method.

Background

Boil-off Gas (BOG) is generated by inevitably absorbing heat from the outside during storage, transportation, unloading, and filling of Liquefied Natural Gas (LNG). The generation of BOG causes the pressure in the LNG storage tank to rise rapidly, when the pressure exceeds the allowable working pressure, the LNG storage tank safety protection device is opened to discharge and decompress the BOG, and the BOG discharged into the outside air easily causes serious potential safety hazard, which is particularly serious in the case of a plurality of LNG tank boxes, such as an LNG carrier or a storage yard.

Therefore, there is a need for improvements in the prior art.

Disclosure of Invention

The invention solves the problems that: when the LNG tank is over-pressurized, directly discharging BOG to the external space may cause a serious problem of safety hazard. The invention provides a gas-phase co-pipe safety protection system and a gas-phase co-pipe safety protection method to solve the problems.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a gas phase co-pipe safety shield system comprising:

an LNG storage system comprising at least ten sets of tank systems, the tank systems comprising LNG tanks storing LNG; the first female joint is connected with a BOG gas phase space inside the LNG tank box through a first connecting pipe; an alarm is arranged on the LNG tank box; a first manual stop valve is arranged on the first connecting pipe;

the main pipeline system comprises a main medium pipeline and a plurality of first male connectors matched with the first female connectors, and each first male connector is connected with the main medium pipeline through a second connecting hose; when the first female connector is inserted into the first male connector, the corresponding first connecting pipe and the second connecting hose are communicated;

the safety monitoring and control system comprises a controller, a first pressure sensor and a second pressure sensor;

the first pressure sensor is used for detecting the pressure value of the BOG gas phase space in the LNG tank; the second pressure sensor is used for detecting the pressure value of the BOG in the main medium pipeline;

the controller is used for receiving the pressure value data sent by the first pressure sensor and the second pressure sensor and controlling the alarm to be turned on and off.

Preferably, the BOG reliquefaction system further comprises a BOG reliquefaction recovery system, wherein the BOG reliquefaction recovery system comprises a regenerative refrigerator, and the regenerative refrigerator comprises a low-temperature heat exchanger; the second medium pipeline is connected between the inlet of the low-temperature heat exchanger and the main medium pipeline; the connection of the second medium pipeline and the main medium pipeline is positioned between the first end and the second end of the main medium pipeline; and a second pneumatic regulating valve is installed on the second medium pipeline, and the controller controls the regenerative refrigerator and the second pneumatic regulating valve to be opened or closed.

Preferably, the BOG reliquefaction device further comprises a BOG reliquefaction storage system, wherein the BOG reliquefaction storage system comprises a spray header and a liquid storage tank, the spray header is arranged in the liquid storage tank and positioned at the top of the liquid storage tank, and the spray header is provided with an inlet extending out of the liquid storage tank; and the third medium pipeline is connected between the inlet of the spray header and the outlet of the low-temperature heat exchanger.

Preferably, the system also comprises a natural gas power system, wherein the natural gas power system comprises a combustion system and a cold energy recovery device; the combustion system is used for combusting BOG to push the gas turbine to operate; a first medium line is connected between an inlet of the combustion system and a first end of the main medium line; a first pneumatic regulating valve is arranged on the main medium pipeline and is close to a first end part of the main medium pipeline; the controller controls the first pneumatic regulating valve to be opened or closed;

the cold energy recovery device is a heat exchanger with a plurality of inlets and a plurality of outlets, and the heat exchanger is arranged in the first medium pipeline, the internal combustion gas turbine air pipeline, the tank transport ship cold air system pipeline and the gas turbine exhaust and circulating cooling water pipeline through different inlets and outlets.

Preferably, the mast ignition system comprises a safety valve, a mast exhaust pipe and an igniter, the second end of the main medium pipeline is connected to the inlet of the mast exhaust pipe, and the outlet of the mast exhaust pipe is communicated with the outside; the igniter is arranged at an outlet of the mast exhaust pipe; the safety valve is arranged at the second end part of the main medium pipeline; the controller controls ignition of the igniter.

Preferably, the safety monitoring and control system further comprises a third pressure sensor, wherein the third pressure sensor is used for detecting the pressure value of the BOG gas phase space in the liquid storage tank;

the fourth medium pipeline is connected with the BOG gas phase space in the liquid storage pipe and the first medium pipeline; a third pneumatic regulating valve is arranged on the fourth medium pipeline;

and the controller controls the third pneumatic regulating valve to be opened and closed.

Preferably, the liquid storage tank further comprises a fifth medium pipeline, a first end of the fifth medium pipeline is connected with the liquid phase space in the liquid storage tank, a second end of the fifth medium pipeline is connected with the BOG gas phase space in the liquid storage tank, and at least one part of the fifth medium pipeline is positioned outside the liquid storage tank;

a first pneumatic stop valve and a self-pressurization heat exchange coil are installed on the fifth medium pipeline, the first pneumatic stop valve and the self-pressurization heat exchange coil are both positioned outside the liquid storage tank, and the first pneumatic stop valve is closer to the first end part of the fifth medium pipeline relative to the self-pressurization heat exchange coil;

one end of the liquid outlet pipeline is connected with the liquid phase space in the liquid storage tank, and a second pneumatic stop valve is installed on the liquid outlet pipeline;

the safety monitoring and control system also comprises a liquid level sensor, and the liquid level sensor is used for detecting the liquid level height of the LNG in the liquid storage tank;

and the safety monitoring and control system is used for controlling the opening and closing of the first pneumatic stop valve and the second pneumatic stop valve.

The invention also provides a gas-phase common pipe safety protection method based on the gas-phase common pipe safety protection system, which comprises the following steps:

s1: when the first pressure sensor detects that the pressure value of the BOG gas phase space in the LNG tank is larger than a first preset value, the controller controls the alarm to be started, the first male connector and the first female connector are manually inserted and combined, and a first manual stop valve is opened; the BOG in the LNG tank box enters the main medium pipeline;

s2: when the pressure value detected by the second pressure sensor is larger than a second preset value, the controller opens the second pneumatic regulating valve, and the BOG in the main medium pipeline flows into the BOG reliquefaction and recovery system;

after the BOG flows into the BOG reliquefaction recovery system, the controller opens the regenerative refrigerator for refrigeration, and the BOG flows through the low-temperature heat exchanger and is liquefied into LNG which is sprayed into the liquid storage tank through the spray header;

s3: when the pressure value in the main medium pipeline is larger than a fourth preset value, the safety valve is automatically opened, and BOG in the main medium pipeline flows into the mast ignition system;

after the BOG flows into the mast ignition system, the controller controls the igniter to be started to ignite the BOG at the outlet of the mast exhaust pipe.

Preferably, between S1 and S2, S11 is further included: the controller controls the first pneumatic regulating valve to be opened, and BOG in a main medium pipeline flows into the natural gas power system;

also included between S2 and S3 is S21: when the difference value between the second pressure sensor and the third pressure sensor is smaller than a third preset value, the controller controls the third pneumatic regulating valve to be opened to guide the BOG in the liquid storage tank into the natural gas power system;

after the BOG flows into the natural gas power system, the BOG exchanges heat through a cold energy recovery device and then flows into the combustion system to be combusted, so that a gas turbine is pushed to operate; in the cold energy recovery device, the BOG in the first medium pipeline exchanges heat with the internal combustion turbine air pipeline, the tank transport ship cold air system pipeline and the gas turbine exhaust and circulating cooling water pipeline.

Preferably, after S3, S4 is also included: when the liquid level sensor detects that the liquid level height of the LNG in the liquid storage tank reaches a fifth preset value, the controller controls the regenerative refrigerator, the second pneumatic regulating valve and the third pneumatic regulating valve to be closed, and controls the first pneumatic stop valve and the second pneumatic stop valve to be opened; LNG in the liquid storage tank flows out of the liquid storage tank through the liquid outlet pipeline for long-term storage.

The invention has the advantages that when the pressure value in a certain LNG tank is larger than the preset value (such as 0.5 MPa), the alarm is started to prompt the staff to connect the LNG tank with the main medium pipeline, so that gas-phase common management is realized, and the storage and transportation safety of LNG is ensured through the triple safety protection of the natural gas power system, the BOG reliquefaction recovery system and the mast ignition system, the maximum utilization and recovery of BOG are realized, and the pollution to the atmospheric environment is reduced.

Drawings

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a schematic structural diagram of a gas-phase co-pipe safety protection system according to the invention.

In the figure 1, an LNG storage system 101, an LNG tank 102, a first female joint 103, a first connecting pipe 104, a first manual shutoff valve 2, a natural gas power system 201, a combustion system 202, a refrigeration recovery device 203, a gas turbine air line 204, a tank carrier cold air system line 205, a gas turbine exhaust and circulating cooling water line 206, a first medium line 3, a BOG reliquefaction recovery system 301, a regenerative refrigerator 302, a cryogenic heat exchanger 303, a third manual shutoff valve 304, a second manual shutoff valve 305, a second pneumatic regulating valve 306, a third medium line 307, a second medium line 4, a safety monitoring and control system 401, a first pressure sensor 402, a second pressure sensor 403, a controller 404, an alarm 405, a third pressure sensor 406, a level sensor, 5. the reliquefaction BOG storage system comprises a 501 spray header, a 502 liquid storage tank, a 503 third pneumatic control valve, 504, a fourth medium pipeline, 505, a self-pressurization heat exchange coil pipe, 506, a first pneumatic stop valve, 507, a liquid outlet pipeline, 508, a second pneumatic stop valve, 509, a fifth medium pipeline, 6, a main pipeline system, 601, a main medium pipeline, 602, a first male connector, 603, a second connecting hose, 604, a first pneumatic control valve, 7, a mast ignition system, 701, a safety valve, 702, a mast exhaust pipe, 703 and an igniter.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the present invention.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

As shown in fig. 1, the present invention provides a gas phase common pipe safety protection system, comprising:

the LNG storage system 1, the LNG storage system 1 includes at least ten sets of tank systems including LNG tanks 101 storing LNG. The first female joint 102 is connected to the BOG gas phase space inside the LNG tank 101 through a first connection pipe 103. The LNG tank 101 is provided with an alarm 404, and specifically, the alarm 404 is an audible and visual alarm. A first manual cut-off valve 104 is mounted on the first connection pipe 103.

The main pipeline system 6, the main pipeline system 6 includes a main medium pipeline 601 and a plurality of first male connectors 602 matching with the first female connectors 102, each first male connector 602 is connected with the main medium pipeline 601 through a second connection hose 603. When the first female connector 102 is inserted into the first male connector 602, the corresponding first connection pipe 103 and second connection hose 603 are connected. In a specific embodiment, the first female connector 102 is a Bayonet cryogenic connector female and the first male connector 602 is a Bayonet cryogenic connector male. Each LNG tank 101 can be connected to the primary media line 601 through a Bayonet cryogenic coupling to enable co-management of the gas phase of the BOG in multiple LNG tanks 101. When first manual stop valve 104 was closed, guaranteed that the gas in the LNG tank 101 can not reveal, improved the security.

The safety monitoring and control system 4, the safety monitoring and control system 4 includes a controller 403, a first pressure sensor 401, and a second pressure sensor 402.

The first pressure sensor 401 is configured to detect a pressure value of a BOG gas phase space in the LNG tank 101; the second pressure sensor 402 is used to detect the pressure value of the BOG in the main medium line 601.

The controller 403 is used for receiving the pressure value data sent by the first pressure sensor 401 and the second pressure sensor 402 and controlling the on and off of the audible and visual alarm 404.

The BOG reliquefaction recovery system 3 includes a regenerative refrigerator 301, and the regenerative refrigerator 301 includes a cryogenic heat exchanger 302 therein. The second medium line 307 is connected between the inlet of the cryogenic heat exchanger 302 and the main medium line 601. The connection of the secondary medium line 307 to the primary medium line 601 is located between the first and second ends of the primary medium line 601. The second medium pipe 307 is provided with a second pneumatic regulating valve 305, and the controller 403 controls the regenerative refrigerator 301 and the second pneumatic regulating valve 305 to open and close. It should be noted that the reliquefaction recovery system may have one or more sets.

In this embodiment, a second manual shutoff valve 304 is installed on the second medium pipe 307, and a third manual shutoff valve 303 is installed on the third medium pipe 306. When the reliquefaction recovery system does not need to work or needs to be maintained and replaced, the second manual stop valve 304 and the third manual stop valve 303 in the reliquefaction recovery system are closed, so that the safety is ensured.

The reliquefaction BOG storage system 5 comprises a spray header 501 and a liquid storage tank 502, wherein the spray header 501 is arranged in the liquid storage tank 502 and is positioned at the top of the liquid storage tank 502, and the spray header 501 is provided with an inlet extending out of the liquid storage tank 502. The third medium pipe 306 is connected between the inlet of the shower head 501 and the outlet of the cryogenic heat exchanger 302. The BOG flows into the cryogenic heat exchanger 302 along the second medium pipeline 307 and absorbs cold, and the temperature is gradually reduced until the BOG is liquefied into LNG. The LNG flows to the spray header 501 after being gathered into the third medium pipeline 306, the LNG is dispersed and sprayed into the liquid storage tank 502 by the spray header 501, the LNG exchanges heat with the BOG in the liquid storage tank 502 in the falling process, the gas temperature is reduced, and the BOG part in the liquid storage tank 502 is liquefied for the second time, so that the purpose of reducing the gas phase space pressure of the BOG in the liquid storage tank 502 is achieved.

According to a further embodiment, the gas-phase co-pipe safety protection system further comprises a natural gas power system 2, the natural gas power system 2 comprising a combustion system 201 and a cold recovery device 202. The combustion system 201 is used to burn BOG to facilitate gas turbine operation. The first medium line 206 is connected between the inlet of the combustion system 201 and a first end of the main medium line 601.

The cold energy recovery device 202 is used for realizing heat exchange between the first medium pipeline 206 and the internal combustion turbine air pipeline 203, the tank transport ship cold air system pipeline 204 and the gas turbine exhaust and circulating cooling water pipeline 205. The main medium pipe 601 is provided with a first pneumatic regulating valve 604, the first pneumatic regulating valve 604 is close to a first end of the main medium pipe 601, and the controller 403 controls the first pneumatic regulating valve 604 to open or close. The cold recovery device 202 is used for recovering cold in the BOG, and for reducing the air inlet temperature of the gas turbine set, cooling the exhaust temperature of the gas turbine and the circulating cooling water system, improving the efficiency of the set, and providing cold to the cold air system of the tank transport ship, thereby avoiding the consumption of a large amount of energy due to work refrigeration. In particular, the cold recovery device 202 is a heat exchanger with a plurality of inlets and a plurality of outlets. The cold recovery device 202 is installed in the first medium line 206, the internal combustion turbine air line 203, the tank carrier cold air system line 204, and the gas turbine exhaust and recirculated cooling water line 205 through different inlets and outlets.

According to further embodiments, the safety monitoring and control system 4 further includes a third pressure sensor 405, the third pressure sensor 405 being configured to detect a pressure value of the BOG vapor space inside the fluid storage tank 502. The fourth medium line 504 is connected to the BOG gas phase space inside the liquid storage tube and the first medium line 206. A third pneumatic regulator valve 503 is installed on the fourth medium line 504. The controller 403 controls the opening and closing of the third pneumatic regulator valve 503.

When the third regulating valve is opened, the BOG in the tank 502 flows into the first medium pipe 206 through the fourth medium pipe 504, and then enters the natural gas power system 2 for combustion.

According to further embodiments, the gas phase co-pipe safety shield system further comprises: a fifth media line 509 having a first end of the fifth media line 509 connected to the liquid phase space within the storage tank 502 and a second end connected to the BOG vapor space within the storage tank 502, and at least a portion of the fifth media line 509 is located outside of the storage tank 502.

The fifth medium pipe 509 is provided with a first pneumatic stop valve 506 and a self-pressurization heat exchange coil 505, the first pneumatic stop valve 506 and the self-pressurization heat exchange coil 505 are both located outside the liquid storage tank 502, and the first pneumatic stop valve 506 is closer to a first end of the fifth medium pipe 509 relative to the self-pressurization heat exchange coil 505.

One end of the liquid outlet pipe 507 is connected with the liquid phase space in the liquid storage tank 502, and the other end of the liquid outlet pipe 507 is communicated to a container (such as a liquefied gas tank) capable of storing LNG for a long time. A second pneumatic stop valve 508 is installed on the liquid outlet pipe 507.

The safety monitoring and control system 4 further includes a level sensor 406, the level sensor 406 being configured to detect a level of LNG within the storage tank 502.

The safety monitoring and control system 4 is used for controlling the opening and closing of the first pneumatic stop valve 506 and the second pneumatic stop valve 508.

When the liquid level sensor 406 detects that the LNG in the liquid storage tank 502 reaches a predetermined value, the controller 403 controls the regenerative refrigerator 301, the second pneumatic regulating valve 305, and the third pneumatic regulating valve 503 to be closed and controls the first pneumatic stop valve 506 and the second pneumatic stop valve 508 to be opened. The LNG in the liquid storage tank 502 flows into the fifth medium pipeline 509, is vaporized after receiving heat from the pressure-increasing heat-exchanging coil 505, and the vaporized LNG flows into the gas phase space of the liquid storage tank 502, so that the pressure in the liquid storage tank 502 is increased, and the LNG in the liquid storage tank 502 is pumped into a container (such as a liquefied gas tank) capable of containing LNG through the liquid outlet pipeline 507 for long-term storage.

According to a further embodiment, such a gas phase co-pipe safety protection system further comprises a mast ignition system 7, the mast ignition system 7 comprising a safety valve 701, a mast exhaust pipe 702 and an igniter 703, the second end of the main media line 601 being connected to an inlet of the mast exhaust pipe 702, an outlet of the mast exhaust pipe 702 being in communication with the outside. An igniter 703 is provided at the outlet of the mast exhaust pipe 702. A relief valve 701 is provided at a second end of the main medium line 601. The controller 403 controls the ignition of the igniter 703.

When the pressure in the main medium line 601 is greater than the set value of the relief valve 701, the relief valve 701 automatically opens, and the BOG in the main medium line 601 flows into the mast exhaust pipe 702, is ignited by an igniter 703 provided at the outlet of the mast exhaust pipe 702, and is discharged.

After the pressure value in a certain LNG tank 101 is larger than a preset value (such as 0.5 MPa), the alarm 404 prompts a worker to connect the LNG tank 101 with the main medium pipeline 601, so that gas-phase co-management is realized, and after the gas-phase co-management, BOG in the main medium pipeline 601 can be led out for disposal, so that the safe protection of the BOG is ensured.

Such a gas-phase co-pipe safety protection system can be applied to a carrier ship of the LNG tank 101 or a yard where the LNG tank 101 is stacked.

The gas-phase co-pipe safety protection system has a triple safety protection function, and when the pressure of the LNG tank 101 is higher than 0.5MPa, the gas-phase space of the LNG tank 101 is communicated with the main medium pipeline 601, so that gas-phase co-pipe is realized. Firstly, introducing BOG in a main medium pipeline 601 into a natural gas power system 2 to be used as fuel for combustion; when the natural gas power system 2 can not be consumed, the BOG re-liquefaction recovery system 3 liquefies BOG, when the BOG in the main medium pipeline 601 is in overpressure, the BOG in the main medium pipeline 601 enters the mast ignition system 7 to be ignited and discharged, and the safety of the whole system is ensured.

The invention also provides a gas-phase common pipe safety protection method based on the gas-phase common pipe safety protection system, which comprises the following steps:

s1: when the first pressure sensor 401 detects that the pressure value of the BOG gas phase space in the LNG tank 101 is greater than a first predetermined value (e.g., 0.5 MPa), the controller 403 controls the alarm 404 to open, manually inserts the first male connector 602 into the first female connector 102, and opens the first manual shutoff valve 104, so that the BOG in the LNG tank 101 enters the main medium pipeline 601.

S2: when the pressure value detected by the second pressure sensor 402 is larger than the second predetermined value, the controller 403 opens the second pneumatic regulating valve 305, and the BOG in the main medium line 601 flows into the BOG reliquefaction recovery system 3.

After the BOG flows into the BOG reliquefaction recovery system 3, the controller 403 opens the regenerative refrigerator 301 to perform refrigeration, and the BOG flows through the cryogenic heat exchanger 302 and is liquefied into LNG which is sprayed into the liquid storage tank 502 through the spray header 501.

S3: when the pressure value in the main medium line 601 is greater than the fourth predetermined value, the relief valve 701 opens automatically and the BOG in the main medium line 601 flows into the mast ignition system 7. After the BOG flows into the mast ignition system 7, the controller 403 controls the igniter 703 to be turned on, and ignites the BOG at the outlet of the mast exhaust pipe 702.

According to further embodiments, between S1 and S2 there is further included S11: the controller 403 controls the first pneumatic regulating valve 604 to open, and the BOG in the main medium line 601 flows into the natural gas power system 2.

Also included between S2 and S3 is S21: when the difference between the second pressure sensor 402 and the third pressure sensor 405 is smaller than the third predetermined value, the controller 403 controls the third pneumatic regulating valve 503 to open to introduce the BOG in the tank 502 into the natural gas power system 2.

After the BOG flows into the natural gas power system 2, the BOG exchanges heat through the cold energy recovery device 202, and then flows into the combustion system 201 to be combusted, so that the gas turbine is pushed to operate; in the coldness recovery device 202, the BOG in the first medium line 206 exchanges heat with the internal combustion turbine air line 203, the tank carrier cold air system line 204, and the gas turbine exhaust gas and recirculated cooling water line 205.

According to further embodiments, following S3, further comprising S4: when the liquid level sensor 406 detects that the liquid level of the LNG in the liquid storage tank 502 reaches a fifth predetermined value, the controller 403 controls the regenerative refrigerator 301, the second pneumatic regulating valve 305, and the third pneumatic regulating valve 503 to be closed and controls the first pneumatic stop valve 506 and the second pneumatic stop valve 508 to be opened; the LNG in the storage tank 502 flows out of the storage tank 502 through the liquid outlet line 507 for long-term storage.

When the gas-phase common-pipe safety protection method is applied to an LNG transport ship, when the pressure of the LNG tank 101 is higher than 0.5MPa, the gas-phase space of the LNG tank 101 is communicated with the main medium pipeline 601, and gas-phase common-pipe is realized. The BOG in the main medium pipeline 601 is firstly led into the natural gas power system 2 to be used as fuel for combustion, when the natural gas power system 2 cannot be consumed, the BOG re-liquefaction recovery system 3 is started to liquefy and recover the BOG, when the BOG in the main medium pipeline 601 is in overpressure, the safety valve 701 automatically jumps, the BOG in the main medium pipeline 601 is ignited and decompressed through the mast ignition system 7, and the safety of the whole system is ensured.

When the gas-phase common-pipe safety protection method is applied to a storage yard, the whole device is not provided with the natural gas power system 2, after the gas-phase common-pipe, BOG in the main medium pipeline 601 is firstly liquefied by the reliquefaction system and then recovered, when the BOG in the main medium pipeline 601 is in overpressure, the safety valve 701 automatically jumps, and the BOG in the main medium pipeline 601 is ignited by the combustion ignition system to be decompressed.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic representation of the term does not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.