A kind of cryogenic gas condensate recovery system and method thereofTechnical field
The present invention relates to field of energy recovery, particularly relate to a kind of cryogenic gas condensate recovery system and method thereof.
Background technology
Liquefied natural gas (LNG) its main component is methane, colourless, tasteless, nontoxic and non-corrosiveness, and its volume is the 1/625 of same amount gaseous natural gas volume, is the fastest a kind of high-quality clean energy resource of current whole world growth rate.Gaseous natural gas is compressed, be cooled to its boiling point (-161.5 DEG C) temperature become LNG after, be stored in cryogenic storage tank, then transported by special purpose ship or tank car, again gasify during use.Compared to gaseous natural gas, LNG is little due to its volume, and efficiency of storage is high, substantial amounts of natural gas transportation to pipeline can be difficult to by special ship or tank car any user arrived, compared with laying underground gas pipeline, not only reduce investment outlay, and convenient and reliable, risk is little, strong adaptability.Along with LNG increases in world's production capacity, demand and application increase, and tank car is widely used as LNG transporting mode the most easily, and the usage quantity of LNG tank car is also being stepped up.
According to incompletely statistics, there is the LNG groove tank car of nearly 4000 in the current whole nation, and according to " liquid gas truck tank safety-supervision regulation " requirement, the tank body of LNG tank car needs periodic inspection, including annual check and complete examination.Wherein annual check is the most at least carried out once, completely examines every 6 years and at least carries out once, and tank body generation major accident or down time, more than 1 year, should completely examine before using.Require in whole drain tank natural gas before annual test and be replaced as safe gas (such as nitrogen etc.).And normally groove tank pressure after unloading can also have remaining liquefied natural gas (LNG) close to about 0.6MPa in part tank.So car owner is before entering annual test place, needing natural gas in drain tank, the most conventional mode is directly emptying, not only wastes the LNG boil-off gas of high-purity, high heating value, there is also environmental pollution and potential safety problem.
It addition, whole nation LNG mounted gas cylinder total amount is also up to 500,000 at present, require every 3 years to gas cylinder inspection once according to " gas cylinder safely Supervision Code ".Require in whole evacuated vial gas pressure before inspection and be replaced as safe gas (such as nitrogen etc.).The most conventional mode is also directly emptying, not only wastes the LNG boil-off gas of high-quality, and there is also environmental pollution and potential safety problem.
Summary of the invention
It is an object of the invention to overcome the deficiency of prior art flow process, it is provided that a kind of cryogenic gas condensate recovery system and method thereof.
Cryogenic gas condensate recovery system includes storage tank, pump, switching valve, the first valve, Cryo Refrigerator, fluid reservoir, the second valve；Storage tank, pump, switching valve the first entrance are sequentially connected, and switching valve outlet port, the first valve, Cryo Refrigerator, fluid reservoir are sequentially connected, and storage tank is connected with switching valve the second entrance, and switching valve outlet port and the second valve are connected.
Described Cryo Refrigerator and the 3rd valve, on-condensible gas collector, drain valve are sequentially connected.Described storage tank is demountable structure with the connection of pump and the connection of storage tank and switching valve the second entrance.Described pump, Cryo Refrigerator, fluid reservoir are positioned on movable fixture.
Cryogenic gas condensation recycling method comprises the steps:
1), when tank inner pressure is more than or equal to switching pressure, pump cuts out, and switching valve is in the second entrance and outlet state, and the first valve is opened, and refrigeration machine is opened, and the second valve cuts out；Gas flows through switching valve, the first valve from storage tank, and entering condensation in Cryo Refrigerator becomes liquid, flows into fluid reservoir；Switching pressure is more than 0 and is less than the design pressure of storage tank；
2) tank inner pressure is less than when switching pressure and be more than or equal to minimum operating pressures that, and switching Vavle switching is the first entrance and outlet state, and pump is opened；Gas flows out from storage tank, first compresses through pumping, passes through switching valve, the first valve, and entering condensation in Cryo Refrigerator becomes liquid, flows into fluid reservoir；Minimum operating pressures that is more than 0 and less than switching pressure；
3) when tank inner pressure is less than minimum operating pressures that, pump cuts out, and switching Vavle switching is the second entrance and outlet state, and the first valve cuts out, and Cryo Refrigerator cuts out, and the second valve is opened；Being filled with substitution gas in storage tank, the gas in storage tank flows out through switching valve, the second valve.
Also comprise the steps:
4), when in on-condensible gas collector, pressure exceedes drain valve setting pressure, drain valve is opened, and incoagulable gas flows out through drain valve；Drain valve sets pressure and is more than 0 and is less than the design pressure of storage tank 1.
The present invention solves the problems such as recycling and the environmental pollution of the natural gas during natural air drain tank car and mounted gas cylinder detection, it is achieved tank body and gas cylinder discharge without natural gas during detection.
Accompanying drawing explanation
Fig. 1 is cryogenic gas condensate recovery system structural representation；
In figure, storage tank 1, pump 2, switching valve the 3, first valve 4, Cryo Refrigerator 5, fluid reservoir the 6, second valve the 7, the 3rd valve 8, on-condensible gas collector 9, drain valve 10.
Detailed description of the invention
As it is shown in figure 1, cryogenic gas condensate recovery system includes storage tank 1, pump 2, switching valve the 3, first valve 4, Cryo Refrigerator 5, fluid reservoir the 6, second valve 7；Storage tank 1, pump 2, switching valve 3 first entrance are sequentially connected, and valve 3 exports, the first valve 4, Cryo Refrigerator 5, fluid reservoir 6 are sequentially connected in switching, and storage tank 1 is connected with switching valve 3 second entrance, and switching valve 3 exports and is connected with the second valve 7.
Described Cryo Refrigerator 5 is sequentially connected with the 3rd valve 8, on-condensible gas collector 9, drain valve 10.Described storage tank 1 is demountable structure with connection and the storage tank 1 of pump 2 with the connection switching valve 3 second entrance.Described pump 2, Cryo Refrigerator 5, fluid reservoir 6 are positioned on movable fixture.
Cryogenic gas condensation recycling method comprises the steps:
1), when in storage tank 1, pressure is more than or equal to switching pressure, pump 2 cuts out, and switching valve 3 is in the second entrance and outlet state, and the first valve 4 is opened, and refrigeration machine 5 is opened, and the second valve 7 cuts out；Gas flows through from storage tank 1 and switches valve the 3, first valve 4, and in entrance Cryo Refrigerator 5, condensation becomes liquid, flows into fluid reservoir 6, and switching pressure is more than 0 and is less than the design pressure of storage tank 1；
2) in storage tank 1, pressure is less than when switching pressure and be more than or equal to minimum operating pressures that, and switching valve 3 switches to the first entrance and outlet state, and pump 2 is opened；Gas flows out from storage tank 1, first through pump 2 suction compression, passes through switching valve the 3, first valve 4, and entering condensation in Cryo Refrigerator 5 becomes liquid, flows into fluid reservoir 6；Minimum operating pressures that is more than 0 and less than switching pressure；
3) when in storage tank 1, pressure is less than minimum operating pressures that, pump 2 cuts out, and switching valve 3 switches to the second entrance and outlet state, and the first valve 4 cuts out, and Cryo Refrigerator 5 cuts out, and the second valve 7 is opened；Being filled with substitution gas in storage tank 1, the gas in storage tank 1 flows out through switching valve the 3, second valve 7.
Also comprise the steps:
4) in on-condensible gas collector 9, pressure exceedes drain valve 10 when setting pressure, and drain valve 10 is opened, and incoagulable gas flows out through drain valve 10；Drain valve 10 sets pressure and is more than 0 and is less than the design pressure of storage tank 1.
Embodiment
1) initial pressure 0.6MPa in storage tank 1, more than or equal to switching pressure 0.1MPa, pump 2 cuts out, and switching valve 3 is in the second entrance and outlet state, and the first valve 4 is opened, and refrigeration machine 5 is opened, and the second valve 7 cuts out；Natural gas flows through switching valve the 3, first valve 4 from storage tank 1, and entering condensation in Cryo Refrigerator 5 becomes liquid, flows into fluid reservoir 6；The on-condensible gas comprised in natural gas flows into on-condensible gas collector 9 from Cryo Refrigerator 5 through valve 8.
2) when pressure is less than switching pressure 0.1MPa in storage tank 1, there are about the natural gas of 86% and be liquefied recoverys in tank, switching valve 3 switches to the first entrance and outlet state, and pump 2 is opened；Natural gas flows out from storage tank 1, first through pump 2 suction compression, passes through switching valve the 3, first valve 4, and entering condensation in Cryo Refrigerator 5 becomes liquid, flows into fluid reservoir 6；The on-condensible gas comprised in natural gas flows into on-condensible gas collector 9 from Cryo Refrigerator 5 through the 3rd valve 8.
3) when in storage tank 1, pressure is less than minimum operating pressures that 0.005MPa, now the natural gas of more than 99% has been liquefied recoverys, and pump 2 cuts out, and switching valve 3 switches to the second entrance and outlet state, and the first valve 4 cuts out, and Cryo Refrigerator 5 cuts out, and the second valve 7 is opened；Being filled with substitution gas nitrogen or dry air in storage tank 1, the gas in storage tank 1 flows out through switching valve the 3, second valve 7.
4) in on-condensible gas collector 9, pressure exceedes drain valve 10 when setting pressure 0.2MPa, and drain valve 10 is opened, and incoagulable gas flows out through drain valve 10；Follow-up tank body detection is carried out after being replaced into nitrogen or dry air in detected tank body.
Fluid reservoir by connecting vaporizer from supercharging mode, or can connect the mode such as immersed pump and externally export liquefied natural gas, can be directly used for the filling of LNG mounted gas cylinder, or carries out liquid feeding to other LNG tanks such as gas station storage tank.