Boiler system applied to LNG emergency peak regulation station

Abstract

The utility model provides a boiler system applied to an LNG emergency peak regulation station. The boiler system comprises a heating and ventilation boiler, a process boiler and a valve assembly. When the heating and ventilation boiler breaks down, process water supply of the process boiler is conveyed to the station area heating equipment and the water bath recuperator through the valve assembly, and process return water of the process boiler is conveyed to the process boiler from the station area heating equipment and the water bath recuperator through the valve assembly. When the process boiler breaks down, heating and ventilation supplied water of the heating and ventilation boiler is conveyed to the water bath recuperator through the valve assembly. The heating and ventilation return water passing through the station area heating equipment before the process boiler breaks down is conveyed to the station area heating equipment again through the valve assembly, and the heating and ventilation return water passing through the water bath recuperator after the process boiler breaks down is conveyed to the heating and ventilation boiler through the valve assembly. By means of the system, the problem that when a process boiler or a heating and ventilation boiler in an existing boiler system breaks down, an LNG emergency peak regulation station cannot operate normally is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a boiler system applied to an LNG emergency peak-shaving station. Background Art

[0002] The LNG (Liquefied Natural Gas) emergency peak-shaving reserve station features "low-temperature LNG storage and ambient temperature return gas supply." LNG (-162°C) stored in the tank is pumped to an air-temperature vaporizer via a cryogenic submersible pump. The vaporized NG (approximately -65°C to +5°C) enters the NG water bath reheater, where it is heated to above 5°C. After pressure regulation, odorization, and metering, it is returned to the municipal pipeline network. Therefore, temperature is a key control factor in the LNG vaporization process. The circulating hot water supply for the water bath reheater comes from a vacuum gas-fired hot water boiler (process boiler), which serves as a heat source and provides 85°C hot water for the process. The hot water system is an open-loop system, divided into two circulation lines: a heating feed water system and a heating return water system. The heating return water returns to the open water tank at 60°C. It is pressurized by a hot water circulation pump and then enters the boiler, where it is heated to 85°C and then sent to the NG water bath reheater.

[0003] Currently, emergency peak-shaving stations all use gas vacuum hot water boilers (HVAC boilers) as heat sources to provide heating hot water for the entire plant, providing 85°C heating hot water for heating purposes, and a return water temperature of 60°C. The hot water system uses a feed water pump to maintain constant pressure. The hot water system is a closed circulation system. The heating return water is pressurized by the hot water circulation pump and enters the boiler, where it is heated to 85°C and sent to various heating hot spots.

[0004] However, in actual operation, each station area operates independently of the other two boilers: the process hot water boiler provides hot water for the station area's process operations, and the heating boiler provides hot water for the station area's heating operations. If either the heating or process boiler fails, the corresponding heat supply process will be interrupted, seriously impacting normal production operations at the station area. Some stations are equipped with multiple boilers. When one boiler fails, heating is immediately switched to another boiler. However, this approach requires large initial investment and high maintenance costs, and some boilers remain idle for long periods of time, resulting in a waste of resources. Utility Model Content

[0005] The present application provides a boiler system applied to an LNG emergency peak-shaving station to solve the problem that the LNG emergency peak-shaving station cannot operate normally when a process boiler or a HVAC boiler in an existing boiler system fails.

[0006] The boiler system comprises:

[0007] HVAC boiler, process boiler and valve assembly, the HVAC boiler and station heating equipment form a hot water circuit, the process boiler and water bath reheater form a hot water circuit;

[0008] When the HVAC boiler fails, the return water end and the water supply end of the HVAC boiler are both closed, and the process supply water of the process boiler is respectively delivered to the station heating equipment and the water bath reheater through the valve assembly, and the process return water of the process boiler is respectively delivered from the station heating equipment and the water bath reheater to the process boiler through the valve assembly;

[0009] When the process boiler fails, the return water end and the water supply end of the process boiler are both closed, and the HVAC water supply of the HVAC boiler is transported to the water bath reheater through the valve assembly; the HVAC return water that passed through the station area heating equipment before the process boiler fails is re-transported to the station area heating equipment through the valve assembly, and the HVAC return water that passed through the water bath reheater after the process boiler fails is transported to the HVAC boiler through the valve assembly.

[0010] Preferably, the boiler system further comprises:

[0011] A water supply station, wherein the water outlet of the water supply station is connected to the HVAC boiler and the process boiler respectively, and the water supply station is configured to provide initial water for the HVAC boiler and the process boiler respectively.

[0012] Preferably, the boiler system further comprises:

[0013] Softening water treatment equipment, the water outlet of the softening water treatment equipment is connected to the HVAC boiler and the process boiler respectively, the water inlet of the softening water treatment equipment is connected to the water supply station, and the softening water treatment equipment is configured to soften the initial water provided by the water supply station.

[0014] Preferably, the boiler system further comprises:

[0015] A constant pressure device, wherein the water inlet end of the constant pressure device is connected to the softened water treatment equipment;

[0016] A first heating circulation pump, wherein the water inlet of the first heating circulation pump is connected to the water outlet of the constant pressure device, and the water outlet of the first heating circulation pump is connected to the return water end of the HVAC boiler.

[0017] Preferably, the boiler system further comprises:

[0018] A water tank, the water inlet end of the water tank is connected to the softening water treatment equipment and the water bath reheater respectively, the water outlet end of the water tank is connected to the process boiler, and the water outlet end of the water tank is connected to the return water end of the HVAC boiler through the valve assembly.

[0019] Preferably, the valve assembly comprises:

[0020] a first pipeline connected between a pipeline at a water supply end of the process boiler and a pipeline at a water supply end of the HVAC boiler;

[0021] a second pipeline connected between a pipeline at a return water end of the process boiler and a pipeline at a return water end of the HVAC boiler;

[0022] When the HVAC boiler fails, the process water supply of the process boiler is transported to the station area heating equipment and the water bath reheater respectively through the pipeline at the process boiler water supply end and the first pipeline, and the process return water of the process boiler is transported to the process boiler through the pipeline at the process boiler return water end and the second pipeline.

[0023] Preferably, the boiler system further comprises:

[0024] a second heating circulation pump, the second heating circulation pump being connected in parallel with the first heating circulation pump;

[0025] The valve assembly further comprises:

[0026] A third pipeline, the third pipeline being connected between the second heating circulation pump and the pipeline at the water supply end of the HVAC boiler;

[0027] When the process boiler fails, the second heating circulation pump is turned on and the first heating circulation pump is turned off. The HVAC supply water of the HVAC boiler is transported to the water bath reheater through the first pipeline. The HVAC return water that passed through the station area heating equipment before the process boiler fails is re-transported to the station area heating equipment through the third pipeline and the second heating circulation pump. After the process boiler fails, the HVAC return water that passed through the water bath reheater is transported to the HVAC boiler through the second pipeline.

[0028] Preferably, the connection point between the first pipeline and the pipeline where the water supply end of the HVAC boiler is located is a first connection point, the connection point between the third pipeline and the pipeline where the water supply end of the HVAC boiler is located is a second connection point, the connection point between the second pipeline and the pipeline where the return end of the HVAC boiler is located is a third connection point, and the connection point between the third pipeline and the pipeline where the return end of the HVAC boiler is located is a fourth connection point;

[0029] The water outlet of the first heating circulation pump is arranged between the third connection point and the fourth connection point, and the water outlet of the second heating circulation pump is arranged between the third connection point and the fourth connection point;

[0030] The third pipeline further includes a first stop valve, a one-way valve, a second stop valve and a third stop valve, wherein the one-way valve and the second stop valve are arranged between the first connection point and the second connection point, the first stop valve is arranged between the water outlet end of the first heating circulation pump and the third connection point, and the third stop valve is arranged between the fourth connection point and the second connection point;

[0031] When the process boiler fails, the first stop valve, the one-way valve, and the second stop valve are closed, and the third stop valve is opened.

[0032] Preferably, the first pipeline comprises a fourth stop valve, a first shower valve and a fifth stop valve connected in series;

[0033] The second pipeline includes a sixth stop valve, a flow regulating valve, a seventh stop valve, a bypass stop valve, a second shower guide valve and an eighth stop valve, wherein the sixth stop valve, the flow regulating valve and the seventh stop valve are connected in series, the flow regulating valve is arranged between the sixth stop valve and the seventh stop valve, the bypass stop valve is connected in parallel between the sixth stop valve and the seventh stop valve, the second shower guide valve and the seventh stop valve are connected in series, and the second shower guide valve is arranged between the eighth stop valve and the seventh stop valve;

[0034] When the process boiler fails, the four stop valves, the first shower valve and the fifth stop valve are opened, the sixth stop valve, the flow regulating valve, the seventh stop valve, the second shower valve and the eighth stop valve are opened.

[0035] Preferably, when the HVAC boiler fails, the fourth stop valve, the first drain valve and the fifth stop valve are opened, the first stop valve, the one-way valve and the second stop valve are opened, the sixth stop valve, the flow regulating valve, the seventh stop valve, the second drain valve and the eighth stop valve are opened, and the third stop valve and the bypass stop valve are closed.

[0036] From the above content, it can be seen that the present application provides a boiler system applied to an LNG emergency peak-shaving station, wherein the boiler system includes a HVAC boiler, a process boiler and a valve assembly, wherein the HVAC boiler and the station heating equipment constitute a hot water passage, and the process boiler and the water bath reheater constitute a hot water passage; when the HVAC boiler fails, the return water end and the water supply end of the HVAC boiler are both closed, and the process water supply of the process boiler is respectively transported to the station heating equipment and the water bath reheater through the valve assembly, and the process return water of the process boiler is respectively transported from the station heating equipment and the water bath reheater to the process boiler through the valve assembly; when the process boiler fails, the return water end and the water supply end of the process boiler are both closed, and the HVAC supply water of the HVAC boiler is transported to the water bath reheater through the valve assembly; the HVAC return water that passed through the station heating equipment before the process boiler fails is re-transported to the station heating equipment through the valve assembly, and the HVAC return water that passed through the water bath reheater after the process boiler fails is transported to the HVAC boiler through the valve assembly. This application solves the problem that the LNG emergency peak-shaving station cannot operate normally when the process boiler or HVAC boiler in the existing boiler system fails through the above system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 This is a schematic diagram of a boiler system used in an LNG emergency peak-shaving station in this application. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0040] Figure 1 This is a schematic diagram of a boiler system used in an LNG emergency peak-shaving station in this application.

[0041] See also Figure 1It can be seen that this embodiment provides a boiler system applied to an LNG emergency peak-shaving station, and the boiler system includes a HVAC boiler 100, a process boiler 200 and a valve assembly 300. The HVAC boiler 100 and the station area heating equipment 400 constitute a hot water passage, and the process boiler 200 and the water bath reheater 500 constitute a hot water passage. Specifically, in this embodiment, when the HVAC boiler 100 and the process boiler 200 are operating normally, the valve assembly 300 is closed, and the HVAC boiler 100 and the process boiler 200 are both operated independently.

[0042] When the HVAC boiler 100 fails, the return water end and the water supply end of the HVAC boiler 100 are both closed, and the process supply water of the process boiler 200 is respectively transported to the station area heating equipment 400 and the water bath reheater 500 through the valve assembly 300, and the process return water of the process boiler 200 is respectively transported from the station area heating equipment 400 and the water bath reheater 500 to the process boiler 200 through the valve assembly 300. Specifically, in this embodiment, when the HVAC boiler 100 fails, the process boiler 200 replaces the HVAC boiler 100 for heating and maintains its own process.

[0043] When the process boiler 200 fails, the return water end and the water supply end of the process boiler 200 are both closed, and the HVAC supply water of the HVAC boiler 100 is transported to the water bath reheater 500 through the valve assembly 300; the HVAC return water that passed through the station area heating equipment 400 before the process boiler 200 fails is re-transported to the station area heating equipment 400 through the valve assembly 300, and the HVAC return water that passed through the water bath reheater 500 after the process boiler 200 fails is transported to the HVAC boiler 100 through the valve assembly 300. Specifically, in this embodiment, when the process boiler 200 fails, the HVAC boiler 100 replaces the process boiler 200 to provide process water, and self-circulates the original warm water used for heating until the failure of the process boiler 200 is eliminated.

[0044] Furthermore, in some embodiments, the boiler system further includes:

[0045] The water supply station 600 has its water outlets connected to the HVAC boiler 100 and the process boiler 200, respectively. The water supply station 600 is configured to provide initial water for the HVAC boiler 100 and the process boiler 200, respectively. Specifically, in this embodiment, the water supply station 600 is used to provide water for the HVAC boiler 100 and the process boiler 200.

[0046] Furthermore, in some embodiments, the boiler system further includes:

[0047] The softening water treatment equipment 700 has a water outlet connected to the HVAC boiler 100 and the process boiler 200 respectively, and a water inlet connected to the water supply station 600. The softening water treatment equipment 700 is configured to soften the initial water provided by the water supply station 600. Specifically, in this embodiment, the softening water treatment equipment 700 is used to soften the initial water provided by the water supply station 600, so as to avoid malfunction of the HVAC boiler 100 and / or the process boiler 200 due to hard water problems.

[0048] Furthermore, in some embodiments, the boiler system further includes:

[0049] A constant pressure device 800, wherein the water inlet end of the constant pressure device 800 is connected to the softened water treatment equipment 700;

[0050] The first heating circulation pump 900, the water inlet end of the first heating circulation pump 900 is connected to the water outlet end of the constant pressure device 800, and the water outlet end of the first heating circulation pump 900 is connected to the return water end of the HVAC boiler 100. Specifically, in this embodiment, the constant pressure device 800 is used to provide softened water to the softened water treatment equipment 700 for constant pressure treatment, so as to avoid the problem that the HVAC boiler 100 cannot operate normally due to insufficient water pressure.

[0051] The first heating circulation pump 900 is used to pressurize and heat the return water of the HVAC boiler 100.

[0052] Furthermore, in some embodiments, the boiler system further includes:

[0053] The water tank 1000 has a water inlet connected to the softening water treatment equipment 700 and the water bath reheater 500, respectively; the water outlet of the water tank 1000 is connected to the process boiler 200; the water outlet of the water tank 1000 is connected to the return water end of the HVAC boiler 100 through the valve assembly 300. Specifically, in this embodiment, the water tank 1000 is used to store a certain amount of water and to replenish the return water of the process boiler 200.

[0054] Furthermore, in some embodiments, the valve assembly 300 includes:

[0055] A first pipeline 310, the first pipeline 310 is connected between the pipeline at the water supply end of the process boiler 200 and the pipeline at the water supply end of the HVAC boiler 100;

[0056] A second pipeline 320, the second pipeline 320 is connected between the pipeline at the return water end of the process boiler 200 and the pipeline at the return water end of the HVAC boiler 100;

[0057] When the HVAC boiler 100 fails, the process supply water of the process boiler 200 is transported to the station area heating equipment 400 and the water bath reheater 500 respectively through the pipeline at the water supply end of the process boiler 200 and the first pipeline 310, and the process return water of the process boiler 200 is transported to the process boiler 200 through the pipeline at the return water end of the process boiler 200 and the second pipeline 320.

[0058] Specifically, in this embodiment, when the HVAC boiler 100 fails, the process boiler 200 supplies water to the station heating equipment 400 and the water bath reheater 500 through the first pipeline 310 , and returns water through the second pipeline 320 .

[0059] Furthermore, in some embodiments, the connection point between the first pipeline 310 and the pipeline at the water supply end of the HVAC boiler 100 is a first connection point, the connection point between the third pipeline 330 and the pipeline at the water supply end of the HVAC boiler 100 is a second connection point, the connection point between the second pipeline 320 and the pipeline at the return end of the HVAC boiler 100 is a third connection point, and the connection point between the third pipeline 330 and the pipeline at the return end of the HVAC boiler 100 is a fourth connection point.

[0060] The water outlet of the first heating circulation pump 900 is arranged between the third connection point and the fourth connection point, and the water outlet of the second heating circulation pump 1100 is arranged between the third connection point and the fourth connection point;

[0061] The third pipeline 330 further includes a first stop valve 331, a one-way valve 332, a second stop valve 333, and a third stop valve 334. The one-way valve 332 and the second stop valve 333 are arranged between the first connection point and the second connection point. The first stop valve 331 is arranged between the water outlet end of the first heating circulation pump 900 and the third connection point. The third stop valve 334 is arranged between the fourth connection point and the second connection point.

[0062] When the process boiler 200 fails, the first stop valve 331 , the one-way valve 332 , and the second stop valve 333 are closed, and the third stop valve 334 is opened.

[0063] Specifically, in this embodiment, the first pipeline 310 includes a fourth stop valve 311, a first drain valve 312, and a fifth stop valve 313 connected in series; the second pipeline 320 includes a sixth stop valve 321, a flow regulating valve 322, a seventh stop valve 323, a bypass stop valve 324, a second drain valve 325, and an eighth stop valve 326. The sixth stop valve 321, the flow regulating valve 322, and the seventh stop valve 323 are connected in series. The flow regulating valve 322 is arranged between the sixth stop valve 321 and the seventh stop valve 323. The bypass stop valve 324 is provided between the sixth stop valve 321 and the seventh stop valve 323. The through-stop valve 324 is connected in parallel between the sixth stop valve 321 and the seventh stop valve 323, the second pilot valve 325 and the seventh stop valve 323 are connected in series, and the second pilot valve 325 is arranged between the eighth stop valve 326 and the seventh stop valve 323; when the process boiler 200 fails, the four stop valves 311, the first pilot valve 312 and the fifth stop valve 313 are opened, and the sixth stop valve 321, the flow regulating valve 322, the seventh stop valve 323, the second pilot valve 325 and the eighth stop valve 326 are opened.

[0064] Specifically, in this embodiment, when the HVAC boiler 100 fails, the fourth stop valve 311, the first drain valve 312 and the fifth stop valve 313 are opened, the first stop valve 331, the one-way valve 332 and the second stop valve 333 are opened, the sixth stop valve 321, the flow regulating valve 322, the seventh stop valve 323, the second drain valve 325 and the eighth stop valve 326 are opened, and the third stop valve 334 and the bypass stop valve 324 are closed.

[0065] It should be noted that the above valves are opened or closed only when the HVAC boiler 100 or the process boiler 200 fails. When the HVAC boiler 100 and the process boiler 200 are working normally, the states of the above valves are opposite.

[0066] The advantages of this embodiment are as follows:

[0067] By adding three pipelines to connect the heating processes of the process boiler and the HVAC boiler, when one of the boilers fails, the other boiler can be used as a backup boiler to provide temporary heating, which can meet the heating requirements of both boilers in the short term. This not only reduces the boiler investment, maintenance and upkeep costs, but also meets the heating needs of production and life in the station area.

Claims

1. A boiler system used in an LNG emergency peak-shaving station, characterized in that: The boiler system comprises a heating boiler (100), a process boiler (200) and a valve assembly (300); the heating boiler (100) and the station heating equipment (400) form a hot water path; and the process boiler (200) and the water bath reheater (500) form a hot water path; When the HVAC boiler (100) fails, the return water end and the water supply end of the HVAC boiler (100) are both closed, and the process supply water of the process boiler (200) is respectively delivered to the station heating equipment (400) and the water bath reheater (500) through the valve assembly (300), and the process return water of the process boiler (200) is respectively delivered from the station heating equipment (400) and the water bath reheater (500) to the process boiler (200) through the valve assembly (300); When the process boiler (200) fails, the return water end and the water supply end of the process boiler (200) are both closed, and the HVAC supply water of the HVAC boiler (100) is transported to the water bath reheater (500) through the valve assembly (300); the HVAC return water that passed through the station heating equipment (400) before the process boiler (200) fails is re-transported to the station heating equipment (400) through the valve assembly (300), and the HVAC return water that passed through the water bath reheater (500) after the process boiler (200) fails is transported to the HVAC boiler (100) through the valve assembly (300).

2. The boiler system used in an LNG emergency peak-shaving station according to claim 1, characterized in that: The boiler system further comprises: A water supply station (600), wherein the water outlet of the water supply station (600) is connected to the HVAC boiler (100) and the process boiler (200) respectively, and the water supply station (600) is configured to provide initial water for the HVAC boiler (100) and the process boiler (200) respectively.

3. The boiler system used in an LNG emergency peak-shaving station according to claim 2, characterized in that: The boiler system further comprises: A softening water treatment device (700) is provided, wherein the water outlet of the softening water treatment device (700) is connected to the HVAC boiler (100) and the process boiler (200) respectively, and the water inlet of the softening water treatment device (700) is connected to the water supply station (600). The softening water treatment device (700) is configured to soften the initial water provided by the water supply station (600).

4. The boiler system used in an LNG emergency peak-shaving station according to claim 3, characterized in that: The boiler system further comprises: A constant pressure device (800), wherein the water inlet end of the constant pressure device (800) is connected to the softened water treatment equipment (700); A first heating circulation pump (900), wherein the water inlet of the first heating circulation pump (900) is connected to the water outlet of the constant pressure device (800), and the water outlet of the first heating circulation pump (900) is connected to the return water end of the HVAC boiler (100).

5. The boiler system used in an LNG emergency peak-shaving station according to claim 4, characterized in that: The boiler system further comprises: A water tank (1000), wherein the water inlet end of the water tank (1000) is connected to the softening water treatment equipment (700) and the water bath reheater (500), respectively, the water outlet end of the water tank (1000) is connected to the process boiler (200), and the water outlet end of the water tank (1000) is connected to the return water end of the HVAC boiler (100) through the valve assembly (300).

6. The boiler system used in an LNG emergency peak-shaving station according to claim 5, characterized in that: The valve assembly (300) comprises: a first pipeline (310), the first pipeline (310) being connected between a pipeline at a water supply end of the process boiler (200) and a pipeline at a water supply end of the HVAC boiler (100); a second pipeline (320), the second pipeline (320) being connected between the pipeline at the return water end of the process boiler (200) and the pipeline at the return water end of the HVAC boiler (100); When the HVAC boiler (100) fails, the process water supply of the process boiler (200) is respectively transported to the station heating equipment (400) and the water bath reheater (500) through the pipeline at the water supply end of the process boiler (200) and the first pipeline (310), and the process return water of the process boiler (200) is transported to the process boiler (200) through the pipeline at the return water end of the process boiler (200) and the second pipeline (320).

7. The boiler system used in an LNG emergency peak-shaving station according to claim 6, characterized in that: The boiler system further comprises: a second heating circulation pump (1100), the second heating circulation pump (1100) being connected in parallel with the first heating circulation pump (900); The valve assembly (300) further comprises: a third pipeline (330), the third pipeline (330) being connected between the second heating circulation pump (1100) and the pipeline at the water supply end of the HVAC boiler (100); When the process boiler (200) fails, the second heating circulation pump (1100) is turned on and the first heating circulation pump (900) is turned off. The HVAC supply water of the HVAC boiler (100) is transported to the water bath reheater (500) through the first pipeline (310). The HVAC return water that passed through the station heating equipment (400) before the process boiler (200) fails is re-transported to the station heating equipment (400) through the third pipeline (330) and the second heating circulation pump (1100). After the process boiler (200) fails, the HVAC return water that passed through the water bath reheater (500) is transported to the HVAC boiler (100) through the second pipeline (320).

8. The boiler system used in an LNG emergency peak-shaving station according to claim 7, characterized in that: The connection point between the first pipeline (310) and the pipeline at the water supply end of the HVAC boiler (100) is a first connection point, the connection point between the third pipeline (330) and the pipeline at the water supply end of the HVAC boiler (100) is a second connection point, the connection point between the second pipeline (320) and the pipeline at the return end of the HVAC boiler (100) is a third connection point, and the connection point between the third pipeline (330) and the pipeline at the return end of the HVAC boiler (100) is a fourth connection point; The water outlet of the first heating circulation pump (900) is arranged between the third connection point and the fourth connection point, and the water outlet of the second heating circulation pump (1100) is arranged between the third connection point and the fourth connection point; The third pipeline (330) further comprises a first stop valve (331), a one-way valve (332), a second stop valve (333) and a third stop valve (334); the one-way valve (332) and the second stop valve (333) are arranged between the first connection point and the second connection point; the first stop valve (331) is arranged between the water outlet end of the first heating circulation pump (900) and the third connection point; and the third stop valve (334) is arranged between the fourth connection point and the second connection point. When the process boiler (200) fails, the first stop valve (331), the one-way valve (332) and the second stop valve (333) are closed, and the third stop valve (334) is opened.

9. The boiler system used in an LNG emergency peak-shaving station according to claim 8, characterized in that: The first pipeline (310) includes a fourth stop valve (311), a first shower valve (312), and a fifth stop valve (313) connected in series. The second pipeline (320) includes a sixth stop valve (321), a flow regulating valve (322), a seventh stop valve (323), a bypass stop valve (324), a second shower valve (325), and an eighth stop valve (326). The sixth stop valve (321), the flow regulating valve (322), and the seventh stop valve (323) are connected in series. The flow regulating valve (322) is arranged between the sixth stop valve (321) and the seventh stop valve (323). The bypass stop valve (324) is connected in parallel between the sixth stop valve (321) and the seventh stop valve (323). The second shower valve (325) and the seventh stop valve (323) are connected in series. The second shower valve (325) is arranged between the eighth stop valve (326) and the seventh stop valve (323). When the process boiler (200) fails, the four stop valves (311), the first drain valve (312) and the fifth stop valve (313) are opened, and the sixth stop valve (321), the flow regulating valve (322), the seventh stop valve (323), the second drain valve (325) and the eighth stop valve (326) are opened.

10. The boiler system used in an LNG emergency peak-shaving station according to claim 9, characterized in that: When the HVAC boiler (100) fails, the fourth stop valve (311), the first drain valve (312) and the fifth stop valve (313) are opened, the first stop valve (331), the one-way valve (332) and the second stop valve (333) are opened, the sixth stop valve (321), the flow regulating valve (322), the seventh stop valve (323), the second drain valve (325) and the eighth stop valve (326) are opened, and the third stop valve (334) and the bypass stop valve (324) are closed.

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