CN111380775A - Device and method for detecting static evaporation rate of gas cylinder - Google Patents

Device and method for detecting static evaporation rate of gas cylinder Download PDF

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Publication number
CN111380775A
CN111380775A CN202010301104.1A CN202010301104A CN111380775A CN 111380775 A CN111380775 A CN 111380775A CN 202010301104 A CN202010301104 A CN 202010301104A CN 111380775 A CN111380775 A CN 111380775A
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gas cylinder
temperature
pressure
collector
evaporation rate
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杨刚
谭粤
李蔚
夏莉
李�杰
马志鹏
张耕
郑任重
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GUANGDONG INSTITUTE OF SPECIAL EQUIPMENT INSPECTION
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GUANGDONG INSTITUTE OF SPECIAL EQUIPMENT INSPECTION
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
    • F17C13/025—Special adaptations of indicating, measuring, or monitoring equipment having the pressure as the parameter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
    • F17C13/026—Special adaptations of indicating, measuring, or monitoring equipment having the temperature as the parameter
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M13/00—Testing of machine parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
    • F17C1/12—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge with provision for thermal insulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0404—Parameters indicated or measured
    • F17C2250/043—Pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
    • F17C2250/04—Indicating or measuring of parameters as input values
    • F17C2250/0404—Parameters indicated or measured
    • F17C2250/0439—Temperature

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  • Mechanical Engineering (AREA)
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Abstract

The invention relates to a device for detecting the static evaporation rate of a gas cylinder, which comprises a temperature collector, a pressure collector and an integrated tester, wherein the temperature collector is connected to the inlet of a pipeline of a gas cylinder vent valve, and the pressure collector is connected to the outlet of the gas cylinder vent valve; the temperature collector and the pressure collector are both connected to the integrated tester through signal cables; or the temperature collector and the pressure collector work independently, and the integrated tester is used for calculating the static evaporation rate of the gas cylinder. The invention also relates to a method for detecting the static evaporation rate of the gas cylinder. The invention can rapidly and accurately measure the static evaporation rate of the gas cylinder without changing working media under the normal working state of the gas cylinder, can improve the detection operability, reduce the detection cost, shorten the detection time and improve the detection efficiency; the integrated tester is provided with a plurality of ports, so that simultaneous detection and calculation of multiple channels can be realized, and the detection time is saved.

Description

Device and method for detecting static evaporation rate of gas cylinder
Technical Field
The invention relates to the field of container performance detection, in particular to a device and a method for detecting the static evaporation rate of a gas cylinder.
Background
The static evaporation rate is an important index for measuring the cold insulation performance of the low-temperature heat-insulation gas cylinder, and is determined according to GB/T34347-: static evaporation rate measurement, each gas cylinder needs at least 24 hours for static evaporation rate test, and a series of working procedures such as working medium replacement, standing, test and the like are not included, so that the time and the power are consumed. Taking an LNG bus as an example, the vehicle-mounted gas cylinder can not be disassembled and assembled at will, so that the weighing method is not suitable for the inspection, the flow meter method needs an inspection period of 4-5 days, the time is too long for the LNG gas cylinder on the bus, and the data acquisition equipment is more complicated, so that the inspection method specified in the current standard is not enough to meet the actual inspection current situation.
Disclosure of Invention
In view of the technical problems in the prior art, the first object of the present invention is to: the detection device can enable the gas cylinder to rapidly and accurately measure the static evaporation rate without changing working media under a normal working state.
The second object of the present invention is: the detection method is a boosting method, can avoid the replacement of working media, effectively shortens the detection time and improves the detection efficiency.
In order to achieve the purpose, the invention adopts the following technical scheme:
a gas cylinder static evaporation rate detection device comprises a temperature collector, a pressure collector and an integrated tester, wherein the temperature collector is connected to the inlet of a gas cylinder vent valve pipeline, and the pressure collector is connected to the outlet of the gas cylinder vent valve; the temperature collector and the pressure collector are both connected to the integrated tester through signal cables; or the temperature collector and the pressure collector work independently, and the integrated tester is used for calculating the static evaporation rate of the gas cylinder.
Further, the integrated tester includes a display panel and a plurality of adjustment keys.
Furthermore, a plurality of ports are arranged on the integrated tester, and the ports can be simultaneously connected with a plurality of signal cables.
Furthermore, the integrated tester, the temperature collector and the pressure collector are all connected with a signal cable through quick connectors.
Furthermore, the range of the temperature collector is-200-150 ℃, the allowable difference value is +/-1 ℃, and the temperature collector is a temperature sensor or a thermocouple.
Furthermore, the range of the pressure collector is 0-4 MPa, the precision is 0.01MPa, and the pressure collector is a pressure sensor or a pressure gauge.
A method for detecting the static evaporation rate of a gas cylinder comprises the following steps:
the first step is as follows: filling a test medium into the gas cylinder to a rated filling rate, and then standing the gas cylinder until thermal equilibrium is reached;
the second step is that: measuring the temperature at the inlet of the gas cylinder vent valve pipeline, and calculating the average temperature value T' at the inlet of the vent valve pipeline;
the third step: weighing the gas cylinder to obtain the total mass m of the test medium in the initial state0；
The fourth step: calculating the volume V of the gas phase space in the initial state according to the initial saturation state equation setgsAnd volume V of liquid phase space in initial statelsThe system of initial saturation state equations is:
Figure BDA0002454017920000021
wherein:
v- -effective volume of gas cylinder, m3；
vgs- -specific volume of gas phase in initial state, m3/Kg；
vls- -specific volume of liquid phase in initial state, m3/Kg；
The fifth step: naturally boosting the pressure of the gas cylinder for several hours, then shaking the medium in the gas cylinder uniformly, and measuring the lowest pressure value at the outlet of the gas cylinder vent valve to obtain the final saturated state pressure;
and a sixth step: calculating the volume V of the gas phase space in the final state according to the final saturated state equation setgfAnd the volume V of the liquid phase space in the final statelfThe final system of saturated state equations is:
Figure BDA0002454017920000022
wherein:
vgf- -specific volume of gas phase in the final state, m3/Kg；
vlf- -specific volume of liquid phase in the final state, m3/Kg；
The seventh step: calculating the heat leakage quantity Q in the test period according to the heat leakage quantity formula of the boosting method0The formula of the heat leakage amount of the boosting method is as follows:
Q0＝(hgf·mgf-hgs·mgs)+(hlf·mlf-hls·mls)
wherein:
hgs-specific enthalpy of the gas phase in the initial state, KJ/Kg;
mgs-mass of gas phase in the initial state, Kg;
hls-specific enthalpy of the liquid phase in the initial state, KJ/Kg;
mls-mass of liquid phase in initial state, Kg;
hgf-specific enthalpy of the gas phase in the final state, KJ/Kg;
mgf-mass of gas phase in the final state, Kg;
hlf-specific enthalpy of the liquid phase in the final state, KJ/Kg;
mlf-mass of liquid phase in final state, Kg;
eighth step: calculating the heat leakage quantity Q' after the environmental temperature correction according to a heat leakage quantity correction formula, wherein the heat leakage quantity correction formula is as follows:
Figure BDA0002454017920000031
wherein:
Figure BDA0002454017920000032
-average temperature over the test period, K;
Ts-initial temperature of the test cycle, K;
Tf-the final temperature of the test cycle, K;
Figure BDA0002454017920000034
-standard temperature, K;
the ninth step: the formula of the heat leakage amount of the weighing method or the flow meter method is as follows: q1＝m·cp·(T'-T0) + m.H, according to Q ═ Q1And calculating the mass m of the evaporated liquid:
Figure BDA0002454017920000033
wherein:
Q1-heat leakage by weighing/flow meter method, KJ;
Cp-the specific heat capacity at constant pressure of the gas at the temperature T', KJ/(Kg · K);
t' - -average temperature at the inlet of the blow valve line, K;
T0temperature of the saturated liquid at standard atmospheric pressure, K;
h- -the latent heat of vaporization of a saturated liquid at standard atmospheric pressure, KJ/Kg;
the tenth step: calculating the daily static evaporation rate according to the daily static evaporation rate formula
Figure BDA0002454017920000042
The daily static evaporation rate formula is:
Figure BDA0002454017920000041
wherein:
rho- -density of saturated liquid at standard atmospheric pressure, Kg/m3；
V- -effective volume of gas cylinder, m3；
n-test time, h.
Further, the total mass m of the test medium in the initial state0Mass m of liquid phase in initial statels。
Furthermore, the natural pressure rise time of the gas cylinder is 6-12 hours.
In summary, the present invention has the following advantages:
the invention can rapidly and accurately measure the static evaporation rate of the gas cylinder without changing working media under the normal working state of the gas cylinder, can improve the detection operability, reduce the detection cost, shorten the detection time and improve the detection efficiency; the integrated tester is provided with a plurality of ports, so that simultaneous detection and calculation of multiple channels can be realized, and the detection time is saved.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Figure 2 is a top view of the gas cylinder of the present invention.
Wherein: 1 is a temperature collector, 2 is a pressure collector, 3 is an integrated tester, 3-1 is a display panel, 3-2 is an adjusting key, 4 is a gas cylinder, 5 is an emptying valve, and 6 is a signal cable.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and detailed description.
As shown in fig. 1 and 2, a device for detecting the static evaporation rate of a gas cylinder comprises a temperature collector, a pressure collector and an integrated tester; the temperature collector is connected to the inlet of the pipeline of the gas cylinder vent valve, the temperature collector selects a temperature sensor or a thermocouple with the range of-200-150 ℃ and the allowable difference value of +/-1 ℃, and the temperature collector is used for measuring the temperature value at the inlet of the pipeline of the gas cylinder vent valve; the pressure collector is connected to the outlet of the gas cylinder vent valve, a pressure sensor or a pressure gauge with the measuring range of 0-4 MPa and the precision of 0.01MPa is selected as the pressure collector, and the pressure collector is used for measuring the pressure value at the outlet of the gas cylinder vent valve; the temperature collector and the pressure collector have two working modes, wherein the first working mode is as follows: the temperature collector and the pressure collector are both connected to the integrated tester through signal cables, and the signal cables can directly transmit the temperature values collected by the temperature collector and the pressure values collected by the pressure collector to the integrated tester; the second working mode is as follows: the temperature collector and the pressure collector are not connected with the integrated tester, the temperature collector and the pressure collector work independently, and then the temperature value collected by the temperature collector and the pressure value collected by the pressure collector are manually input to the integrated tester; the integrated tester is used for calculating the static evaporation rate of the gas cylinder.
As shown in fig. 1, the integrated tester includes a display panel and a plurality of adjustment keys, the adjustment keys are located under the display panel, the display panel can display a plurality of basic parameters, collected temperature values, collected pressure values, heat leakage amounts and obtained static evaporation rates, and the plurality of adjustment keys can correspondingly input and adjust corresponding data; still be equipped with a plurality of ports on the integrated form tester, many signal cables can be connected simultaneously to a plurality of temperature collector and pressure collector through many signal cable connections, can gather the temperature value and the pressure value of a plurality of gas cylinders simultaneously, realize that the multichannel detects simultaneously and calculates, save check-out time, improve detection efficiency. Integrated form tester, temperature collector, pressure collector all are connected with signal cable through quick-operation joint, and in this embodiment, the BNC adapter is chooseed for use to the quick-operation joint.
When using this device to detect the static evaporation rate of gas cylinder, temperature collector and pressure collector select for use a kind of working method, temperature collector and pressure collector all connect on integrated form tester through signal cable promptly, then connect the temperature collector in the import department of gas cylinder atmospheric valve pipeline again, keep the atmospheric valve to open, all the other valves are all closed, measure the temperature of the import department of gas cylinder atmospheric valve pipeline, the temperature of the import department of gas inflow atmospheric valve pipeline in the collection bottle promptly, the temperature value of the import department of record gas cylinder atmospheric valve pipeline, and calculate temperature average. Then connect the pressure collector in the exit of gas cylinder atmospheric valve, keep the atmospheric valve open, all the other valves are closed, make inside the whole gas cylinder carry out the nature 6 ~ 12 hours that steps up, because the pressure collector is connected in the exit of gas cylinder atmospheric valve, cause the gas can not outwards flow in the bottle, it is inclosed in the whole gas cylinder, so the in-process pressure that stews can rise, after 6 ~ 12 hours static pressure rise, shake the medium in the bottle evenly, make the test medium be in final saturated state, the in-bottle pressure can descend at this in-process, measure the minimum pressure value in the exit of gas cylinder atmospheric valve, the minimum after the recording bottle internal pressure descends promptly. In the process, the average temperature value collected by the temperature collector and the minimum pressure value collected by the pressure collector can be transmitted to the integrated tester through the signal cable and can be displayed through the display panel of the integrated tester, then a plurality of basic parameters are set on the integrated tester, and the final static evaporation rate can be obtained through a series of formula operations in the integrated tester.
A method for detecting the static evaporation rate of a gas cylinder comprises the following steps:
the first step is as follows: filling a test medium into the gas cylinder to a rated filling rate, and then standing the gas cylinder until the thermal balance is reached, wherein the test medium can be liquid nitrogen, liquefied natural gas or other media;
the second step is that: connecting a temperature collector at the inlet of a pipeline of the gas cylinder emptying valve, keeping the emptying valve open, closing the other valves, measuring the temperature at the inlet of the pipeline of the gas cylinder emptying valve, and calculating the average temperature value T' at the inlet of the pipeline of the emptying valve;
the third step: removing the temperature collector, weighing the gas cylinder, and subtracting the dead weight of the gas cylinder from the total weight of the obtained gas cylinder to obtain the total mass m of the test medium in the gas cylinder0That is, the total mass m of the test medium in the initial state is obtained0(ii) a When the gas cylinder reaches the rated filling rate, the gas phase space is very small, so the mass of the gas phase part can be ignored, and the total mass m of the test medium in the initial state0It is equal to the mass of the liquid phase in the initial state, i.e.: m is0＝mlsWherein:
m0-total mass of test medium in initial condition, Kg;
mls-mass of liquid phase in initial state, Kg;
the fourth step: in the initial state, the test medium in the bottle is in the initial saturation state under the standard atmospheric pressure, and knowing that the atmospheric pressure in the initial saturation state is the standard atmospheric pressure, an initial saturation state equation set can be obtained, wherein the initial saturation state equation set is as follows:
Figure BDA0002454017920000061
wherein:
v- -effective volume of gas cylinder, m3；
Vgs- -volume of gas phase space in initial state, m3；
Vls- -volume of liquid phase space in initial state, m3；
vgs- -specific volume of gas phase in initial state, m3/Kg；
vls- -specific volume of liquid phase in initial state, m3/Kg；
Knowing the initial saturation state of the atmosphere to be the standard atmosphere, v can be obtainedgsAnd vlsAnd V and m0All are known quantities, and V can be calculated according to the initial saturated state equation setgsAnd Vls；
The fifth step: connecting a pressure collector at an outlet of an air vent valve of the air bottle, keeping the air vent valve open, closing the other valves, naturally boosting the pressure in the whole air bottle for 6-12 hours, ensuring no loss of a test medium in the whole process, shaking the medium in the air bottle uniformly, enabling the test medium to be in a final saturated state, reducing the pressure in the air bottle in the process, measuring the lowest pressure value at the outlet of the air vent valve of the air bottle, namely recording the lowest value after the pressure in the air bottle is reduced, wherein the lowest value is the pressure in the final saturated state;
and a sixth step: knowing the final saturation state pressure, a final saturation state equation set can be obtained, the final saturation state equation set being:
Figure BDA0002454017920000071
wherein:
Vgf- -volume of gas space in the final state, m3；
Vlf- -volume of liquid phase space in final state, m3；
vgf- -specific volume of gas phase in the final state, m3/Kg；
vlf- -specific volume of liquid phase in the final state, m3/Kg；
Knowing the final saturation pressure, v can be obtainedgfAnd vlfAnd V and m0All are known quantities, and V can be calculated according to the final saturated state equation setgfAnd Vlf；
The seventh step: the method for measuring the static evaporation rate of the gas cylinder is a boosting method, a thermodynamic model of the boosting method is a closed system, and according to an energy balance equation of the thermodynamic closed system: obtaining a heat leakage formula of the boosting method by taking the total heat absorption as the final state heat-initial state heat, wherein the heat leakage formula of the boosting method is as follows:
Q0＝(hgf·mgf-hgs·mgs)+(hlf·mlf-hls·mls)
wherein:
Q0- -test periodHeat leakage of (1), KJ;
hgs-specific enthalpy of the gas phase in the initial state, KJ/Kg;
mgs-mass of gas phase in the initial state, Kg;
hls-specific enthalpy of the liquid phase in the initial state, KJ/Kg;
mls-mass of liquid phase in initial state, Kg;
hgf-specific enthalpy of the gas phase in the final state, KJ/Kg;
mgf-mass of gas phase in the final state, Kg;
hlf-specific enthalpy of the liquid phase in the final state, KJ/Kg;
mlf-mass of liquid phase in final state, Kg;
knowing the initial saturation pressure as the standard atmospheric pressure, h can be obtainedgsAnd hls(ii) a Knowing the final saturation pressure, h can be obtainedgfAnd hlf(ii) a And in the fourth step V has already been calculatedgsAnd VlsIn the sixth step, V has already been calculatedgfAnd VlfAnd v isgs、vls、vgf、vlfAll the quantities are known, and m can be calculated according to the specific volume V as the volume V/mass mgs、mls、mgf、mlfThen, Q can be calculated according to the formula of the heat leakage quantity of the boosting method0；
Eighth step: because the heat transfer process is continuously carried out, and the measurement process is influenced by the ambient temperature, the heat leakage quantity needs to be corrected and calculated, and the correction formula of the heat leakage quantity is as follows:
Figure BDA0002454017920000081
wherein:
q' - -the amount of leakage heat after ambient temperature correction, KJ;
Figure BDA0002454017920000082
- -test periodK;
Ts-initial temperature of the test cycle, K;
Tf-the final temperature of the test cycle, K;
Figure BDA0002454017920000085
-standard temperature, K;
in the seventh step Q has already been calculated0To do so
Figure BDA0002454017920000083
Ts、Tf、
Figure BDA0002454017920000084
All the quantities are known quantities, and Q' can be calculated according to a heat leakage quantity correction formula;
the ninth step: the traditional method for measuring the static evaporation rate of the gas cylinder is a weighing method or a flowmeter, a thermodynamic model of the weighing method or the flowmeter is an opening system, and according to an energy balance equation of the thermodynamic opening system: the total heat absorption amount is liquid phase heat absorption and gas phase heat absorption, and a heat leakage formula of a weighing method or a flow meter method can be obtained, wherein the heat leakage formula of the weighing method or the flow meter method is as follows:
Q1＝m·cp·(T'-T0)+m·H
wherein:
Q1-heat leakage by weighing/flow meter method, KJ;
m-mass of evaporated liquid, Kg;
Cp-the specific heat capacity at constant pressure of the gas at the temperature T', KJ/(Kg · K);
t' - -average temperature at the inlet of the blow valve line, K;
T0temperature of the saturated liquid at standard atmospheric pressure, K;
h- -the latent heat of vaporization of a saturated liquid at standard atmospheric pressure, KJ/Kg;
because the heat leakage quantity of the closed system and the open system in the measuring process is approximately equal, the heat leakage quantity obtained by adopting the boosting method is equal to that obtained by adopting a scaleHeat leakage from heavy or flow meters, i.e. Q' ═ Q1(ii) a Thus:
Figure BDA0002454017920000091
in the eighth step Q' has already been calculated, and Cp、T’、T0H is known quantity, and m can be calculated according to a formula;
the tenth step: calculating the daily static evaporation rate, wherein the daily static evaporation rate formula is as follows:
Figure BDA0002454017920000092
wherein:
Figure BDA0002454017920000093
-daily static evaporation rate in percent per day (%/d);
rho- -density of saturated liquid at standard atmospheric pressure, Kg/m3；
V- -effective volume of gas cylinder, m3；
n-test time, h;
in the ninth step, m is calculated, and rho and V, n are both known quantities, and the daily static evaporation rate formula is used to calculate
Figure BDA0002454017920000094
In the actual operation process, knowing the saturation pressure of the test medium, a plurality of physical parameters such as saturation temperature, specific volume, enthalpy value, specific heat capacity, latent heat of vaporization and the like corresponding to gas phase and liquid phase can be obtained by reading a graph, looking up a saturated physical parameter table, looking up a fluid medium data volume and the like, and then the daily static evaporation rate can be obtained by calculating through the series of formulas. In the embodiment, a plurality of physical property parameters of the test medium form a database, the database is put into an integrated tester, then a series of formulas for calculating daily static evaporation rate are also put into the integrated tester,an automatic solving system is formed, and when measured data are input into the integrated tester, the integrated tester can automatically operate to obtain a final result. If the temperature collector and the pressure collector are both connected to the integrated tester through the signal cable, the signal cable can directly transmit the collected temperature average value T' and the final saturation state pressure at the inlet of the emptying valve pipeline to the integrated tester, and the integrated tester can obtain the daily static evaporation rate through operation
Figure BDA0002454017920000101
Or the temperature collector and the pressure collector are not connected with the integrated tester, the temperature collector and the pressure collector work independently, the collected temperature average value T' at the inlet of the emptying valve pipeline and the collected final saturation state pressure are manually input to the integrated tester, and the daily static evaporation rate can also be obtained by the integrated tester through calculation
Figure BDA0002454017920000102
The invention uses a closed system testing method (a boosting method) to replace the traditional open system testing method (a weighing method/a flow meter method), belongs to a new gas cylinder static evaporation rate testing method, can effectively shorten the testing time, reduces the original at least 24 hours to only 6-12 hours, can avoid the replacement of working media, improves the testing level of the gas cylinder static evaporation rate, and provides support and guarantee for the supervision and the development of the regular inspection of related products of the gas cylinder.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (9)

1. The utility model provides a static evaporation rate detection device of gas cylinder which characterized in that: the device comprises a temperature collector, a pressure collector and an integrated tester, wherein the temperature collector is connected to the inlet of a pipeline of the gas cylinder vent valve, and the pressure collector is connected to the outlet of the gas cylinder vent valve; the temperature collector and the pressure collector are both connected to the integrated tester through signal cables; or the temperature collector and the pressure collector work independently, and the integrated tester is used for calculating the static evaporation rate of the gas cylinder.
2. A gas cylinder static evaporation rate detection device according to claim 1, characterized in that: the integrated tester includes a display panel and a plurality of adjustment keys.
3. A gas cylinder static evaporation rate detection device according to claim 1, characterized in that: the integrated tester is provided with a plurality of ports, and the ports can be simultaneously connected with a plurality of signal cables.
4. A gas cylinder static evaporation rate detection device according to claim 1, characterized in that: the integrated tester, the temperature collector and the pressure collector are all connected with a signal cable through quick connectors.
5. A gas cylinder static evaporation rate detection device according to claim 1, characterized in that: the range of the temperature collector is-200-150 ℃, the allowable difference value is +/-1 ℃, and the temperature collector is a temperature sensor or a thermocouple.
6. A gas cylinder static evaporation rate detection device according to claim 1, characterized in that: the range of the pressure collector is 0-4 MPa, the precision is 0.01MPa, and the pressure collector is a pressure sensor or a pressure gauge.
7. A method for detecting the static evaporation rate of a gas cylinder is characterized by comprising the following steps: the method comprises the following steps:
the first step is as follows: filling a test medium into the gas cylinder to a rated filling rate, and then standing the gas cylinder until thermal equilibrium is reached;
the second step is that: measuring the temperature at the inlet of the gas cylinder vent valve pipeline, and calculating the average temperature value T' at the inlet of the vent valve pipeline;
the third step: weighing the gas cylinder to obtain the total mass m of the test medium in the initial state0；
The fourth step: calculating the volume V of the gas phase space in the initial state according to the initial saturation state equation setgsAnd volume V of liquid phase space in initial statelsThe system of initial saturation state equations is:
Figure FDA0002454017910000011
wherein:
v- -effective volume of gas cylinder, m3；
vgs- -specific volume of gas phase in initial state, m3/Kg；
vls- -specific volume of liquid phase in initial state, m3/Kg；
The fifth step: naturally boosting the pressure of the gas cylinder for several hours, then shaking the medium in the gas cylinder uniformly, and measuring the lowest pressure value at the outlet of the gas cylinder vent valve to obtain the final saturated state pressure;
and a sixth step: calculating the volume V of the gas phase space in the final state according to the final saturated state equation setgfAnd the volume V of the liquid phase space in the final statelfThe final system of saturated state equations is:
Figure FDA0002454017910000021
wherein:
vgf- -specific volume of gas phase in the final state, m3/Kg；
vlf- -specific volume of liquid phase in the final state, m3/Kg；
The seventh step: calculating the heat leakage quantity Q in the test period according to the heat leakage quantity formula of the boosting method0The formula of the heat leakage amount of the boosting method is as follows:
Q0＝(hgf·mgf-hgs·mgs)+(hlf·mlf-hls·mls)
wherein:
hgs-specific enthalpy of the gas phase in the initial state, KJ/Kg;
mgs-mass of gas phase in the initial state, Kg;
hls-specific enthalpy of the liquid phase in the initial state, KJ/Kg;
mls-mass of liquid phase in initial state, Kg;
hgf-specific enthalpy of the gas phase in the final state, KJ/Kg;
mgf-mass of gas phase in the final state, Kg;
hlf-specific enthalpy of the liquid phase in the final state, KJ/Kg;
mlf-mass of liquid phase in final state, Kg;
eighth step: calculating the heat leakage quantity Q' after the environmental temperature correction according to a heat leakage quantity correction formula, wherein the heat leakage quantity correction formula is as follows:
Figure FDA0002454017910000022
wherein:
Figure FDA0002454017910000031
-average temperature over the test period, K;
Ts-initial temperature of the test cycle, K;
Tf-the final temperature of the test cycle, K;
Figure FDA0002454017910000032
-standard temperature, K;
the ninth step: the formula of the heat leakage amount of the weighing method or the flow meter method is as follows: q1＝m·cp·(T'-T0) + m.H, according to Q ═ Q1And calculating the mass m of the evaporated liquid:
Figure FDA0002454017910000033
wherein:
Q1-heat leakage by weighing/flow meter method, KJ;
Cp-the specific heat capacity at constant pressure of the gas at the temperature T', KJ/(Kg · K);
t' - -average temperature at the inlet of the blow valve line, K;
T0temperature of the saturated liquid at standard atmospheric pressure, K;
h- -the latent heat of vaporization of a saturated liquid at standard atmospheric pressure, KJ/Kg;
the tenth step: calculating the daily static evaporation rate according to the daily static evaporation rate formula
Figure FDA0002454017910000034
The daily static evaporation rate formula is:
Figure FDA0002454017910000035
wherein:
rho- -density of saturated liquid at standard atmospheric pressure, Kg/m3；
V- -effective volume of gas cylinder, m3；
n-test time, h.
8. A method for detecting the static evaporation rate of a gas cylinder according to claim 7, characterized in that: total mass m of test medium in initial state0Mass m of liquid phase in initial statels。
9. A method for detecting the static evaporation rate of a gas cylinder according to claim 7, characterized in that: the natural pressure rise time of the gas cylinder is 6-12 hours.
CN202010301104.1A 2020-04-16 2020-04-16 Device and method for detecting static evaporation rate of gas cylinder Pending CN111380775A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113074318A (en) * 2021-02-03 2021-07-06 合肥通用机械研究院有限公司 Static low-temperature storage tank daily evaporation rate dynamic calculation method
CN114235886A (en) * 2021-11-22 2022-03-25 华南理工大学 Method for testing boosting rule of LNG (liquefied natural gas) cylinder

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113074318A (en) * 2021-02-03 2021-07-06 合肥通用机械研究院有限公司 Static low-temperature storage tank daily evaporation rate dynamic calculation method
CN114235886A (en) * 2021-11-22 2022-03-25 华南理工大学 Method for testing boosting rule of LNG (liquefied natural gas) cylinder

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