The pressure security control system and method for cryogenic liquid prestressed concrete full appearance tankTechnical field
The present invention relates to large-scale low-temperature liquid prestressed concrete full appearance tank technical fields, and in particular to cryogenic liquid is answered in advanceThe pressure security control system and method for power concrete full appearance tank.
Background technique
Currently, the basin for storing cryogenic fluids gradually develops to the prestressed concrete full appearance tank of large capacity, ruleMould is expanded to 16 ten thousand steres or more from two ten thousand steres；The operating temperature of its storing liquid is lower than -100 DEG C, and belongs toFlammable explosive gas is not only huge economic loss, more may cause the harm of personnel and environment once accident occurs.So the operational safety of Large scale cryogenic liquid tank becomes most crucial problem, because prestressed concrete low-temperature storage tank belongs to oftenTank is pressed, higher pressure cannot be born, so the pressure of control cryogenic liquid tank is to guarantee the important guarantor of storage tank safe operationCard.The pressure of basin is more than design pressure, and prestressed concrete native tank can rupture, and cryogenic liquid is caused to leak outside, and generates the wind such as explosionDanger；The pressure of basin is lower than design pressure, becomes negative pressure, can make storage tank unstability, damage.
Summary of the invention
Aiming at the problems existing in the prior art, the present invention provides the pressure of cryogenic liquid prestressed concrete full appearance tankSafety control system and method.
Technical scheme is as follows:
The pressure security control system of large-scale low-temperature liquid prestressed concrete full appearance tank, which is characterized in that including pressure gauge, pressurePower transmitter, control system, emergency cut-off system, liquid pump, liquid flowing valve, tonifying Qi valve, row torch control valve, compressor,Safety valve and vacuum suction valve；
The pressure gauge, pressure transmitter are mounted at the top of cryogenic liquid tank, measure the pressure of cryogenic liquid tank and with controlSystem processed is connected with emergency cut-off system, the measurement for pressure；
The control system, is mounted on central control room, is connected by signal and pressure transmitter, valve, liquid pump and compressorIt connects, for showing, alarming, controlling and controlling interlocking to pressure in cryogenic liquid tank；
The emergency cut-off system, is mounted on central control room, passes through signal and pressure transmitter, valve, liquid pump and compressionMachine connection, it is chain in emergency circumstances stopping；
The liquid pump is connect with cryogenic liquid tank, for sending out the liquid in cryogenic liquid tank, causes cryogenic liquidSump pressure decline；
The compressor is connect with cryogenic liquid tank, for extracting and compressing the BOG gas in cryogenic liquid tank out, is causedPressure decline in cryogenic liquid tank,
The safety valve is connect with cryogenic liquid tank, for BOG gas in cryogenic liquid tank to be emitted into torch；
The vacuum suction valve is connect with cryogenic liquid tank, for that will prevent cryogenic liquid tank from negative pressure occurs；
The liquid flowing valve is connect with cryogenic liquid tank, for controlling liquid discharging to cryogenic liquid tank, causes Low Temperature LiquidThe pressure of body basin rises；
Row's torch control valve is connect with cryogenic liquid tank, for the BOG gas in cryogenic liquid tank to be discharged to torch,The pressure in cryogenic liquid tank is caused to decline；
The aeration valve is connect with cryogenic liquid tank, for adding to nitrogen in cryogenic liquid tank, causes cryogenic liquidPressure in basin rises.
The pressure security control method of the large-scale low-temperature liquid prestressed concrete full appearance tank, which is characterized in that packetInclude following steps:
For step 1) when the pressure of cryogenic liquid tank is higher than service pressure, control system, which receives, is mounted on cryogenic liquidThe pressure signal of the pressure transmitter of tank top starts to alarm；When pressure, which continues to rise, reaches controlling value, control system is certainlyDynamic starting compressor；When pressure, which continues to rise, reaches the first interlocking value, control system continues to run compressor, closes liquid feed valveDoor, the row's of opening torch control valve；When pressure, which continues to rise, reaches the second interlocking value, emergency cut-off system closes all liq pumpWith compressor and the electrical source of power of unit is cut off, closes low-temperature storage tank；When pressure continues to rise to third interlocking value, peaceFull valve take-off pressure release.
For step 2 when the pressure of cryogenic liquid tank is lower than service pressure, control system reception is mounted on Low Temperature LiquidThe pressure signal of the pressure transmitter of body tank top starts to alarm；When pressure continues to drop to the first interlocking value, control systemIt unites and issues stop signal to compressor；When pressure continues to drop to the second interlocking value, emergency cut-off system closing liquid pump andCompressor simultaneously cuts off electrical source of power；When pressure continues to drop to third interlocking value and aeration valve is opened, supplements Low Temperature Liquid rapidlyThe pressure of body basin；When pressure still drops to four interlocking values, vacuum suction valve is opened, and guarantees that cryogenic liquid tank does not go outExisting negative pressure.
The beneficial effects of the present invention are: the control system and control method are fully able to ensure large-scale low-temperature prestressed concreteThe safety of native full appearance tank, no matter due to weather or operation or failure and other reasons caused by sump pressure rising or underDrop, control that can be safe is within the scope of the design pressure of basin.
Detailed description of the invention
Fig. 1 is the overall structure diagram of invention；
In figure: PICAS-1, PICAS-2, PIAZ-3 are pressure transmitter, and PG-1 is site pressure table, and V1, V4 are cuttingValve, V2, V3 are the regulating valve of provided with electromagnetic valve, and AS1, AS2 are safety valve, and AS3 is vacuum suction valve, and P-1 is cryogenic liquidPump, B-1 are BOG compressor, and T-1 is cryogenic liquid tank, and US-1, US-2 are DCS logic function block, and UZ-1 is ESD logicFunctional block.
Specific embodiment
Below in conjunction with Figure of description, the invention will be further described.
As shown in Figure 1, the pressure security control system of cryogenic liquid prestressed concrete full appearance tank mainly includes eight portionsPoint:
1) pressure transmitter PICAS-1, PICAS-2, PIAZ-3 is mounted at the top of cryogenic liquid tank, measurement cryogenic liquid storageThe pressure of tank is simultaneously connect with control system and emergency cut-off system, is mainly used for the measurement of cryogenic liquid tank pressure, PICAS-1, tri- pressure transmitters of PICAS-2 and PIAZ-3 all use safety instrument integrity levels to assess according to different safety requirementsInstrument, to reach highest security level and accuracy.1 pressure gauge PG-1 of situ configuration proofreads pressure with inspection on siteTransmitter is used.
2) control system (DCS), is mounted on central control room.Logic function block US-1, US-2 in control system DCS is logicalIt crosses signal and liquidometer, PICAS-1, PICAS-2, cryogenic liquid pump P-1, BOG compressor B-1 and valve V1, V2, V3, V4 connectsIt connects, is mainly used for the display, alarm and control interlocking to pressure in cryogenic liquid tank.
3) emergency cut-off system (ESD), is mounted on central control room.Logic function block in emergency cut-off system (ESD)UZ-1 is connect by signal with pressure transmitter PIAZ-3, cryogenic liquid pump P-1, BOG compressor B-1 and valve V1, V2, V4,It is mainly used in emergency circumstances stopping chain.
4) liquid pump P-1 is connect with cryogenic liquid tank；For sending out the liquid in cryogenic liquid tank, cause lowThe decline of geothermal liquid sump pressure.
5) liquid flowing valve V1, V2, row torch control valve V3, aeration valve V4 are connect with cryogenic liquid tank；Low temperature ship orLow-temperature tanker is caused liquid discharging to cryogenic liquid tank in the pressure of cryogenic liquid tank by input duct and valveIt rises；It arranges torch control valve and the BOG gas in cryogenic liquid tank is discharged to torch, cause under the pressure in cryogenic liquid tankDrop；Aeration valve V4 adds to nitrogen in cryogenic liquid tank, and the pressure in cryogenic liquid tank is caused to rise.Wherein V1, V4For quick action emergency valve, V2, V3 are the regulating valve of provided with electromagnetic valve.
6) compressor B-1 is connect with cryogenic liquid tank；For extracting and pressing the BOG gas in cryogenic liquid tank outContracting, causes the pressure in cryogenic liquid tank to decline.
7) safety valve AS1, AS2 is mounted at the top of cryogenic liquid tank, is reached safety valve in cryogenic liquid tank pressure and is risenWhen jump value, safety valve outwardly atmosphere discharge gas.The safety valve uses the using and the reserved, to ensure cryogenic liquid tank safety.
8) vacuum suction valve AS3 is mounted at the top of cryogenic liquid tank, subatmospheric in cryogenic liquid tank pressureWhen, vacuum suction valve sucks air to atmosphere, guarantees that cryogenic liquid tank does not generate negative pressure.
The pressure security control method of cryogenic liquid prestressed concrete full appearance tank: specific step is as follows:
1) when the pressure of cryogenic liquid tank is higher than service pressure, control system (DCS) receives pressure transmitterPICAS-1, PICAS-2 signal manually select one piece of pressure transmitter therein as control input element, to select PICAS-For 1, another pressure transmitter PICAS-2 is used as monitoring alarm detecting element automatically, when wherein any one pressure is believedNumber reach alarming value, starts to alarm；When pressure, which continues to rise, reaches controlling value, control system (DCS) receives pressure transmitterPICAS-1 signal, logic function block US-1 issue signal, and BOG compressor B-1 is started automatically, extract in cryogenic liquid tankBOG gas；If pressure continues to rise, when reaching the first interlocking value, control system (DCS) continues to run BOG compressor, closesLiquid flowing valve V1, V2, the row of opening torch control valve V3；If pressure continues to rise, when reaching the second interlocking value, emergency cut-off systemSystem (ESD) closes all liq pump and compressor and the electrical source of power for cutting off unit, closes cryogenic liquid tank；When pressure stillWhen continuing to rise to third interlocking value, safety valve jumping up pressure release guarantees low temperature liquid storage tank not superpressure.
2) when the pressure of cryogenic liquid tank is lower than service pressure, control system (DCS) receives pressure invertingThe pressure signal of device PICAS-1, PICAS-2 manually select one piece of pressure transmitter therein as control input element, with choosingFor selecting PICAS-1, another pressure transmitter PICAS-2 is used as monitoring alarm detecting element automatically, when wherein any oneA pressure signal reaches alarming value, starts to alarm；When pressure, which continues decline, reaches first setting value, control system (DCS)Logic function block US-2 issues stopping signal to BOG compressor B-1, liquid pump P-1；When pressure continues to drop to the second interlocking valueWhen, emergency cut-off system (ESD) logic function block UZ-1 issues signal, closes BOG compressor B-1, liquid pump P-1 and cuts off dynamicPower power supply；When pressure continues to drop to third interlocking value and aeration valve V4 is opened, supplements the pressure of cryogenic liquid tank rapidly；When pressure still drops to four interlocking values, vacuum suction valve is opened, and guarantees that negative pressure does not occur in cryogenic liquid tank.