Liquefied natural gas tank for external supply of BOG

Abstract

The utility model relates to the technical field of energy, aims to solve the problem of how to continuously and stably supply BOG externally, and provides a liquefied natural gas tank for supplying BOG externally. The liquefied natural gas tank for external supply of BOG comprises a tank body, a BOG delivery pipeline and a nitrogen supplementing pipe. The tank body is used for storing liquefied natural gas. The BOG delivery pipeline is arranged at the top of the tank body, the BOG delivery pipeline is communicated with the tank body, and the BOG delivery pipeline is used for externally supplying BOG. And the nitrogen supplementing pipe extends to the bottom of the tank body, communicates with the tank body and is used for inputting normal-temperature nitrogen into the LNG in the tank body, so that the LNG in the tank body is heated and volatilized. According to the liquefied natural gas tank for external supply of BOG, the top of the tank body is communicated with the BOG delivery pipeline for external supply of BOG, the bottom of the tank body is communicated with the nitrogen supplementing pipe, the nitrogen supplementing pipe inputs normal-temperature nitrogen into LNG in the tank body when the BOG delivery pipeline externally supplies BOG, the normal-temperature nitrogen supplements pressure in the tank body, heat of the normal-temperature nitrogen promotes volatilization of the LNG, and the pressure in the tank body is reduced. Therefore, the effect of continuously and stably supplying BOG externally is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy, in particular to a liquefied natural gas tank for external supply of BOG. BACKGROUND

[0002] LNG (liquefied natural gas) is generally stored in a metal full containment tank, and the liquefied natural gas exists in a liquid phase in a low-temperature and normal-pressure environment. In the prior art, the LNG storage tank is provided with a complete BOG recovery facility, and the BOG is sent to a fuel gas external supply pipeline system.

[0003] In the prior art, when the LNG storage tank supplies a large amount of fuel gas to the fuel gas system, the pressure of the LNG storage tank drops sharply, which is not conducive to the liquid phase volatilization of the LNG, resulting in a decrease in the amount of externally supplied BOG, and causing the BOG to be unable to be continuously and stably supplied. How to solve the above technical problem is a consideration for those skilled in the art. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a liquefied natural gas tank for external supply of BOG to solve the problem of how to continuously and stably supply BOG.

[0005] The embodiment of the present application provides a liquefied natural gas tank for external supply of BOG, which comprises a tank body, a BOG external delivery pipeline and a nitrogen supplement pipeline. The tank body is used for storing liquefied natural gas. The BOG external delivery pipeline is arranged at the top of the tank body, the BOG external delivery pipeline is in communication with the tank body, and the BOG external delivery pipeline is used for external supply of BOG. The nitrogen supplement pipeline extends to the bottom of the tank body, the nitrogen supplement pipeline is in communication with the tank body, and the nitrogen supplement pipeline is used for inputting normal-temperature nitrogen into LNG in the tank body to make the LNG in the tank body volatilize by heat.

[0006] Compared with the prior art, the liquefied natural gas tank for external supply of BOG provided by the embodiment is provided with the BOG external delivery pipeline in communication with the top of the tank body for external supply of BOG, and the nitrogen supplement pipeline in communication with the bottom of the tank body. The nitrogen supplement pipeline inputs normal-temperature nitrogen into the LNG in the tank body when the BOG external delivery pipeline externally supplies BOG. The normal-temperature nitrogen supplements the pressure in the tank body, and the heat of the normal-temperature nitrogen promotes the volatilization of the LNG, thereby improving the liquid phase volatilization of the LNG to achieve the effect of continuously and stably externally supplying BOG.

[0007] In a possible implementation manner, the nitrogen supplement pipeline comprises a pipeline body, the pipeline body extends from the outside of the tank body to the bottom of the tank body, and the pipeline body is used for delivering the normal-temperature nitrogen to the bottom of the LNG in the tank body.

[0008] In a possible implementation manner, the nitrogen supplement pipeline further comprises a plurality of purge rings, the plurality of purge rings are arranged at intervals at the bottom of the tank body, the purge rings are in communication with the pipeline body, and the purge rings are used for blowing the normal-temperature nitrogen into the LNG in the tank body.

[0009] In a possible implementation, the purge ring comprises a ring portion, the ring portion being hollow and in communication with the pipe body, and the ring portion being provided with a plurality of exhaust holes for exhausting the normal-temperature nitrogen.

[0010] In a possible implementation, the liquefied natural gas tank for external supply of BOG further comprises a screw compressor arranged outside the tank body, the screw compressor being connected with the BOG external delivery pipeline, and the screw compressor being used for compressing the BOG drawn out of the tank body to reach a working pressure.

[0011] In a possible implementation, the nitrogen supplement pipe is connected with a helium pipe network, and the helium pipe network is used for providing the normal-temperature nitrogen for the nitrogen supplement pipe. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0013] Figure 1 FIG. 1 is a structural schematic diagram of a liquefied natural gas tank for external supply of BOG according to an embodiment of the present application;

[0014] Figure 2 FIG. 2 is a top view schematic diagram of the liquefied natural gas tank for external supply of BOG according to the embodiment of the present application. Figure 1

[0015] Main element symbol explanation:

[0016] 1, liquefied natural gas tank for external supply of BOG; 11, tank body; 111, outer shell; 112, inner liner; 113, support system; 12, BOG external delivery pipeline; 13, nitrogen supplement pipe; 131, pipe body; 132, purge ring; 133, ring portion; 134, exhaust hole; 14, screw compressor. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0018] Some embodiments of the present application are described in detail. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] EMBODIMENTS​

[0020] Referring to Figure 1 and Figure 2 As shown in the figure, the embodiment provides a liquefied natural gas tank 1 for BOG supply, which comprises a tank body 11, a BOG supply pipeline 12 and a nitrogen supplement pipeline 13. The tank body 11 is used for storing liquefied natural gas (LNG). The BOG supply pipeline 12 is arranged at the top of the tank body 11, and the BOG supply pipeline 12 is in communication with the tank body 11, and the BOG supply pipeline 12 is used for BOG supply. The nitrogen supplement pipeline 13 extends to the bottom of the tank body 11, and the nitrogen supplement pipeline 13 is in communication with the tank body 11, and the nitrogen supplement pipeline 13 is used for inputting normal-temperature nitrogen into the LNG in the tank body 11 to heat and volatilize the LNG in the tank body 11.

[0021] The tank body 11 of the liquefied natural gas tank 1 for BOG supply provided by the embodiment is in communication with the BOG supply pipeline 12 at the top of the tank body 11 for BOG supply, and the tank body 11 is in communication with the nitrogen supplement pipeline 13 at the bottom of the tank body 11. When the BOG supply pipeline 12 supplies BOG, the nitrogen supplement pipeline 13 inputs normal-temperature nitrogen into the LNG in the tank body 11, the normal-temperature nitrogen supplements the pressure in the tank body 11, and the heat of the normal-temperature nitrogen promotes the volatilization of the LNG, thereby improving the liquid-phase volatilization of the LNG, reducing the speed of the pressure drop of the LNG storage tank, and continuously and stably supplying BOG. In this way, the liquefied natural gas tank 1 for BOG supply can improve the quality of fuel gas, reduce the risk of excessively low pressure of the storage tank, and reduce the occurrence of safety accidents caused by equipment damage.

[0022] In the embodiment, the liquefied natural gas tank 1 for BOG supply blows normal-temperature and lower-boiling-point nitrogen into the tank body 11 through the nitrogen supplement pipeline 13 to accelerate the gasification of the LNG liquid phase, generate a large amount of BOG gas with high heat value, and thereby meet the long-term demand for high-heat-value fuel gas of the existing start-up heating furnace, sulfur recovery and the like.

[0023] The tank body 11 is a liquefied natural gas storage tank for vehicles, and the tank body 11 is a high-vacuum adiabatic container for storing liquefied natural gas on a vehicle. The tank body 11 comprises an outer shell 111, an inner container 112 and a support system 113. The inner container 112 of the tank body 11 is used for storing low-temperature liquid LNG, the outer wall of the inner container 112 is wrapped with multiple layers of adiabatic material, has super-strong heat insulation performance, and meanwhile the outer shell 111 and the inner container 112 are pumped to high vacuum, to jointly form a good adiabatic system. The outer shell 111 and the support system 113 are designed to be able to withstand the relevant external force generated when the transport vehicle is running. The existing LNG low-temperature storage tank is used to prepare high-heat-value fuel gas, to meet the demand for high-heat-value fuel gas for the temperature rise of the synthetic raw material gas when the system is started and for the use of the sulfur recovery device when it is started.

[0024] In a possible implementation, the nitrogen supplement pipe 13 comprises a pipe body 131 extending from the outside of the tank body 11 to the bottom of the tank body 11, and the pipe body 131 is used to deliver normal-temperature nitrogen to the bottom of the LNG in the tank body 11.

[0025] In the embodiment, the pipe body 131 extends into the tank body 11 from the top of the tank body 11, and the pipe body 131 is inserted into the LNG in the tank body 11, so that the normal-temperature nitrogen is input to the LNG, and the heat of the normal-temperature nitrogen promotes the evaporation of the LNG, thereby continuously and stably supplying the BOG.

[0026] In a possible implementation, the nitrogen supplement pipe 13 further comprises a plurality of purge rings 132 arranged at intervals at the bottom of the tank body 11, and the purge rings 132 are in communication with the pipe body 131, and the purge rings 132 are used to blow the normal-temperature nitrogen into the LNG in the tank body 11.

[0027] In the embodiment, the purge rings 132 blow the normal-temperature nitrogen, thereby increasing the contact area of the normal-temperature nitrogen and the LNG, so that the normal-temperature nitrogen and the LNG are in sufficient contact to promote the evaporation of the LNG, thereby continuously and stably supplying the BOG.

[0028] In a possible implementation, the purge rings 132 comprise ring portions 133 which are hollow and in communication with the pipe body 131, and the ring portions 133 are provided with a plurality of exhaust holes 134 for exhausting the normal-temperature nitrogen.

[0029] In the embodiment, the ring portions 133 are in the shape of a circular ring, and the purge rings 132 uniformly blow and exhaust the normal-temperature nitrogen to the LNG liquid layer through the plurality of exhaust holes 134, thereby increasing the contact area of the normal-temperature nitrogen and the LNG, so that the normal-temperature nitrogen and the LNG are in sufficient contact to promote the evaporation of the LNG, thereby continuously and stably supplying the BOG.

[0030] In a possible implementation, the liquefied natural gas tank 1 for supplying the BOG further comprises a screw compressor 14 arranged outside the tank body 11, and the screw compressor 14 is connected with the BOG delivery pipeline 12, and the screw compressor 14 is used to compress the BOG drawn out of the tank body 11 to reach the working pressure.

[0031] In the embodiment, the liquefied natural gas tank 1 for supplying the BOG draws the BOG in the tank through the screw compressor 14, and maintains the pressure in the tank while sending the BOG to the fuel gas system. The nitrogen supplement pipe 13 inputs the normal-temperature nitrogen to the LNG in the tank body 11 when the BOG is delivered through the BOG delivery pipeline 12, and the normal-temperature nitrogen supplements the pressure in the tank body 11. Meanwhile, the boiling point of nitrogen is lower than that of methane, and the nitrogen does not affect the purity of the LNG in the tank, thereby continuously and stably supplying a large amount of the BOG for a long time.

[0032] In one possible implementation, the nitrogen supplement gas pipe 13 is connected with a helium pipe network for providing normal-temperature nitrogen gas for the nitrogen supplement gas pipe 13.

[0033] In the present embodiment, the LNG storage tank is generally provided with a common helium pipe network for boil-off and cold tank, and the helium pipe network for boil-off and cold tank is connected with the nitrogen supplement gas pipe 13 to provide normal-temperature nitrogen gas for the nitrogen supplement gas pipe 13. When a larger amount of BOG is required, the nitrogen supplement gas pipe 13 is connected with an appropriate amount of normal-temperature nitrogen gas, and the heat carried by the normal-temperature nitrogen gas is used to promote the evaporation of LNG, and the boiling point of nitrogen is lower than that of methane, so that the nitrogen gas does not affect the purity of LNG in the tank, so that the liquefied natural gas tank 1 for external supply of BOG can supply a larger amount of BOG for a long time, the pressure of the liquefied natural gas tank 1 for external supply of BOG is stable, and the safety and economy are higher.

[0034] The liquefied natural gas tank 1 for external supply of BOG greatly increases the evaporation amount of LNG by uniformly blowing an appropriate amount of nitrogen to prepare high-calorific-value fuel gas, and then the high-calorific-value fuel gas is pressurized by a screw compressor 14 and sent to a fuel gas pipe network to meet the demand of high-calorific-value fuel gas for system start-up such as heating of raw material gas of an ammonia synthesis start-up furnace and heating of a sulfur recovery combustion furnace device. The original mode of supplying liquid LNG by vehicle and then gasifying on site to supply BOG is completely changed, which not only greatly saves the cost of liquefied gas procurement, but also is more convenient, fast and safe. The liquefied natural gas tank 1 for external supply of BOG can supply a large amount of BOG to a fuel gas user for a long time while ensuring the pressure of the LNG storage tank, and the safety and economy are higher, which greatly reduces the cost and risk of purchasing vehicle-mounted liquefied gas and then gasifying. About two-thirds of the cost can be saved. At the same time, the safety and convenience of operation are greatly reduced, and the use risk is reduced. The problem of gas supply under the conditions of weather and traffic control is avoided.

[0035] The above embodiments are only used to illustrate the technical solutions of the present application and not to limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application.

Claims

1. A liquefied natural gas tank for external supply of BOG, characterized in that, Comprise: a tank body for storing liquefied natural gas; a BOG export pipeline arranged at the top of the tank body, the BOG export pipeline being in communication with the tank body, the BOG export pipeline being used for exporting BOG; a nitrogen supplement pipeline extending to the bottom of the tank body, the nitrogen supplement pipeline being in communication with the tank body, the nitrogen supplement pipeline being used for inputting normal-temperature nitrogen gas into liquefied natural gas in the tank body to make liquefied natural gas in the tank body volatilize by heat.

2. The liquefied natural gas tank for exporting BOG according to claim 1, wherein: the nitrogen supplement pipeline comprises a pipeline body extending from the outside of the tank body to the bottom of the tank body, the pipeline body being used for delivering the normal-temperature nitrogen gas to the bottom of liquefied natural gas in the tank body.

3. The liquefied natural gas tank for exporting BOG according to claim 2, wherein: the nitrogen supplement pipeline further comprises a plurality of purge rings arranged at intervals at the bottom of the tank body, the purge rings being in communication with the pipeline body, the purge rings being used for blowing the normal-temperature nitrogen gas into LNG in the tank body.

4. The liquefied natural gas tank for exporting BOG according to claim 3, wherein: the purge ring comprises a ring portion, the ring portion being hollow and in communication with the pipeline body, the ring portion being provided with a plurality of exhaust holes for exhausting the normal-temperature nitrogen gas.

5. The liquefied natural gas tank for exporting BOG according to claim 1, wherein: the liquefied natural gas tank for exporting BOG further comprises a screw compressor arranged outside the tank body, the screw compressor being connected with the BOG export pipeline, the screw compressor being used for compressing BOG drawn out of the tank body to make the BOG reach working pressure.

6. The liquefied natural gas tank for exporting BOG according to claim 1, wherein: the nitrogen supplement pipeline is connected with a helium pipeline network, the helium pipeline network being used for providing the normal-temperature nitrogen gas of the nitrogen supplement pipeline.

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