阅读说明：本技术 一种bog回收装置 (BOG recovery unit ) 是由 王国营 白江坤 范晖 王沙沙 于 2020-07-01 设计创作，主要内容包括：本发明公开了一种BOG回收装置,涉及LNG气瓶技术领域,包括与LNG气瓶连通的第一管道和第二管道,所述第一管道的一端连通所述LNG气瓶的上部,另一端连通华斯特林机的进气口；所述第二管道的一端连通所述LNG气瓶的底部,另一端连通华斯特林机的出液口；所述华斯特林机下端的水平高度高于所述LNG气瓶的上端；所述第一管道上设置有第一阀门。本发明的优点在于,独创了车载LNG气瓶BOG的回收工艺流程,区别传统气瓶,实现了BOG的回收利用。BOG采用华斯特林机进行BOG再液化,对车载LNG气瓶排放的气体进行回收利用,燃气车的安全排放进一步降低可有效的降低排放污染。(The invention discloses a BOG recovery device, which relates to the technical field of LNG gas cylinders and comprises a first pipeline and a second pipeline which are communicated with the LNG gas cylinder, wherein one end of the first pipeline is communicated with the upper part of the LNG gas cylinder, and the other end of the first pipeline is communicated with a gas inlet of a Stirling engine; one end of the second pipeline is communicated with the bottom of the LNG cylinder, and the other end of the second pipeline is communicated with a liquid outlet of the Stirling engine; the horizontal height of the lower end of the Stirling engine is higher than the upper end of the LNG cylinder; the first pipeline is provided with a first valve. The method has the advantages that the method creates the BOG recovery process flow of the vehicle-mounted LNG gas cylinder originally, is different from the traditional gas cylinder, and realizes the BOG recovery. BOG adopts the hua stirling machine to carry out BOG reliquefaction, recycles the gas that on-vehicle LNG gas cylinder discharged, and the safe emission of gas car further reduces and can effectual reduction emission pollution.)

1. A BOG recovery device is characterized by comprising a first pipeline and a second pipeline which are communicated with an LNG gas cylinder, wherein one end of the first pipeline is communicated with the upper part of the LNG gas cylinder, and the other end of the first pipeline is communicated with a gas inlet of a Stirling engine; one end of the second pipeline is communicated with the bottom of the LNG cylinder, and the other end of the second pipeline is communicated with a liquid outlet of the Stirling engine; the horizontal height of the lower end of the Stirling engine is higher than the upper end of the LNG cylinder; the first pipeline is provided with a first valve.

2. The BOG recovery device of claim 1, wherein a second valve and a check valve are disposed on the second pipeline, a bypass pipeline is disposed between the second valve and the check valve, a water bath vaporizer is disposed on the bypass pipeline, the second valve is adjacent to the LNG cylinder, and the check valve is adjacent to the stirling engine.

3. The BOG recovery device of claim 1, wherein the second pipe is provided with a branch pipe, and the branch pipe is provided with a third valve.

4. The BOG recovery device of claim 3, wherein the second pipe is provided with a booster pump between the stirling engine and the bypass pipe.

5. The BOG recovery device according to claim 3, wherein the LNG tank is provided with a safety valve.

Technical Field

The invention relates to the technical field of LNG (liquefied natural gas) gas cylinders, in particular to a BOG (boil off gas) recovery device.

Background

The LNG gas cylinder for the automobile is a special gas cylinder for storing low-temperature liquefied gas (LNG), is mainly used for heavy truck natural gas automobiles to replace traditional fuel vehicles, and has a special storage form. Natural gas has high calorific value, low pollution, small volume after liquefaction, and convenient storage and transportation, thus being concerned about and widely used. However, liquefied natural gas is stored and transported at about-160 ℃, which is easily affected by external heat invasion and other factors, so that a large amount of BOG (boil-off gas) is generated, the LNG storage equipment is subjected to overpressure, the safe operation of a station is affected, and in gases generating a greenhouse effect, direct emission of BOG causes energy consumption and economic loss, and also affects environmental protection. At present, BOG suitable for vehicle-mounted LNG cylinders can be recovered by adopting a reliquefaction process, BOG to be liquefied is used as a refrigerant, and the BOG is liquefied by adopting a single-stage compression and single-stage expansion plus throttling refrigeration method. When the system pressure reaches the designed control value, the BOG reliquefaction device is automatically started to liquefy a part of redundant BOG in the system, so that the temperature and the pressure in the system are reduced, and when the system pressure is reduced to the required value, the reliquefaction device is automatically stopped. BOG in the storage tank enters a compressor after cold energy is recovered by a heat exchanger, natural gas at high pressure and high temperature is cooled by an air cooler firstly, then is further cooled and liquefied in the heat exchanger, then is throttled to low pressure and then is subjected to gas-liquid separation, the separated gas returns to the heat exchanger to be reheated to normal temperature and then returns to the compressor, one part of the separated liquid is pumped back to the LNG storage tank by an LNG low-temperature pump of an LNG gas station, and the other part of the separated liquid enters the heat exchanger to provide cold energy and then returns to the compressor to form circulation.

Disclosure of Invention

The invention provides a BOG recovery device different from the prior art, which adopts the following technical scheme: a BOG recovery device comprises a first pipeline and a second pipeline which are communicated with an LNG gas cylinder, wherein one end of the first pipeline is communicated with the upper part of the LNG gas cylinder, and the other end of the first pipeline is communicated with a gas inlet of a Stirling engine; one end of the second pipeline is communicated with the bottom of the LNG cylinder, and the other end of the second pipeline is communicated with a liquid outlet of the Stirling engine; the horizontal height of the lower end of the Stirling engine is higher than the upper end of the LNG cylinder; the first pipeline is provided with a first valve.

Preferably, a second valve and a check valve are arranged on the second pipeline, a branch pipeline is arranged between the second valve and the check valve, a water bath vaporizer is arranged on the branch pipeline, the second valve is close to the LNG gas cylinder, and the check valve is close to the Stirling engine.

Preferably, a branch pipeline is arranged on the second pipeline, and a third valve is arranged on the branch pipeline.

Further, a booster pump is arranged on the second pipeline and is positioned between the Stirling engine and the branch pipeline.

Further, a safety valve is arranged on the LNG cylinder.

A BOG recovery method for an LNG gas cylinder uses a vehicle-mounted power supply and a Stirling engine to liquefy BOG gas.

The invention has the advantages that the Stirling engine is adopted to carry out BOG reliquefaction, the gas discharged from the vehicle-mounted LNG cylinder is recycled, the safe discharge of the gas vehicle is further reduced, and the discharge pollution can be effectively reduced.

Drawings

FIG. 1 is a schematic structural diagram according to a first embodiment;

FIG. 2 is a schematic structural diagram of the second embodiment;

FIG. 3 is a schematic structural diagram according to a third embodiment;

fig. 4 is a schematic structural diagram of a fourth embodiment.

Detailed Description

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