Performance failure testing device for low-temperature valve for LNG and testing method thereof

Abstract

The utility model provides a kind of performance failure testing device of cryogenic valve for LNG, including medium gas source supply system, enclosed box and cryogenic valve test station;The cryogenic valve test station is located in enclosed box, and drive mechanism and the cryogenic valve to be measured connected with it are installed on cryogenic valve test station, nitrogen concentration sensor, temperature sensor and gas outlet pipe are installed on the side wall of enclosed box, the medium gas source supply system includes raw material storage tank, raw material gas supply main pipe and multiple branch distribution pipe, wherein the inlet of raw material gas supply main pipe is connected with raw material storage tank and manual valve is installed on it, the outlet of raw material gas supply main pipe is connected with multiple branch distribution pipe, valve and solenoid valve are installed on each branch distribution pipe, and the outlet of solenoid valve is connected with the cryogenic valve to be measured through gas inlet pipe.The utility model can guarantee to determine and quantitatively evaluate the applicable performance of cryogenic valve for LNG under normal working condition, and the test process is safe and reliable, the test sequence before and after is reasonable, the test time is short, and test medium can be saved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquefied natural gas supply, and particularly relates to a performance failure testing device for a low-temperature valve for LNG and a testing method thereof. BACKGROUND

[0002] In recent years, liquefied natural gas has been widely used as a clean energy, and the market demand for low-temperature valves suitable for LNG delivery is also increasing. The performance reliability of low-temperature gas valves as important nodes in the LNG supply system restricts the overall safety of the LNG supply system.

[0003] However, the existing standard and literature propose a testing device and method for the reliability and service life of low-temperature valves, which is externally cooled and uses external refrigerants to cool the valve. This test method suitable for simulating external environment has insufficient pertinence to the mechanism of the overall performance failure of the valve, and even qualified valve products have the risk of rapid sealing failure in normal use. SUMMARY

[0004] In order to solve the technical problem of sealing and locking failure caused by the difference between the test and the actual working condition in the existing external cooling method, the application provides a performance failure testing device for a low-temperature valve for LNG. The testing device adjusts the valve time based on the dynamic driving device in the system under the conditions of low-temperature working condition, operating frequency and gas operating condition, forms different low-temperature working time, and obtains the quantitative adaptability and performance change curve through the nitrogen concentration sensor on the low-temperature valve tool and the valve torque and flow monitoring system of the testing device system.

[0005] Another object of the application is to provide a testing method of the performance failure testing device for a low-temperature valve for LNG, which can ensure the determination and quantitative evaluation of the applicable performance of the low-temperature valve for LNG under the premise of normal work, and the testing process is safe and reliable, the testing sequence before and after is reasonable, the testing time is short, and the testing medium can be saved.

[0006] The technical scheme of the present application is conceived as above, which is a performance failure testing device for low-temperature valves for LNG, characterized in that it comprises a medium gas source supply system, a closed box and a low-temperature valve testing station; the low-temperature valve testing station is located in the closed box, and a driving mechanism and a to-be-tested low-temperature valve connected thereto are installed on the low-temperature valve testing station; nitrogen concentration sensors and temperature sensors are installed on the side wall of the closed box, and a gas outlet pipe is installed on the side wall of the closed box; the medium gas source supply system comprises a raw material storage tank, a raw material gas supply main pipe and multiple branch distribution pipes, wherein the inlet of the raw material gas supply main pipe is connected to the raw material storage tank and a manual valve is installed on the inlet; the outlet of the raw material gas supply main pipe is connected to the multiple branch distribution pipes; a valve and an electromagnetic valve are installed on each branch distribution pipe, and the outlet of the electromagnetic valve is connected to the to-be-tested low-temperature valve through a gas inlet pipe; the electromagnetic valve on each branch distribution pipe, the nitrogen concentration sensors and the temperature sensors on the closed box and the driving mechanism on the low-temperature valve testing station are all connected to a control host PLC through data / signal transmission lines.

[0007] Further, the driving mechanism is composed of a torque and displacement sensor and a servo motor connected thereto.

[0008] Further, nitrogen concentration sensors and temperature sensors are installed on the upper part, the middle part and the bottom part of one side wall of the closed box.

[0009] Further, the raw material gas supply main pipe and the multiple branch distribution pipes are pipelines composed of metal pipes with a diameter of ≤200 mm.

[0010] Further, the gas inlet pipe connected to the outlet of the electromagnetic valve is a pipeline composed of metal pipes with a diameter of ≤150 mm.

[0011] The testing method of the above-mentioned performance failure testing device for low-temperature valves for LNG comprises the following steps:

[0012] ① Installing to-be-tested low-temperature valves, nitrogen concentration sensors and temperature sensors: one or more to-be-tested low-temperature valves are respectively placed on the low-temperature valve testing station, the low-temperature valve testing station is located in the closed box, the gas inlet of the to-be-tested low-temperature valve is connected to the corresponding LNG gas supply pipe, the gas outlet is connected to the corresponding gas outlet pipe on the side wall of the closed box, and nitrogen concentration sensors and temperature sensors are installed on the upper part, the middle part and the bottom part of one side wall of the closed box;

[0013] ② Starting the medium gas source supply system to supply internal medium to the to-be-tested low-temperature valve to simulate the actual operating state;

[0014] ③Initial temperature change and corresponding time test: at the beginning of the test, first open the electromagnetic valve, observe the situation of the released liquid nitrogen in the closed box, and correspond with the surface temperature of the closed box collected by the temperature sensor and transmitted to the control host PLC, to obtain a series of temperature and time changes of the temperature sensor collection points, to determine the maximum flow, nominal flow and 5-30% nominal flow state of the external temperature of the low temperature valve under the stable state of the time;

[0015] ④Maximum flow working performance, air tightness and torque change test: liquid nitrogen is supplied to the low temperature valve to be tested through the gas inlet pipe, and after the maximum flow stabilizes, the electromagnetic valve is closed, the torque, surface temperature, nitrogen concentration and test number of the low temperature valve to be tested are collected and counted by the control host PLC, when a process is completed, the cycle is restarted, and when the torque is greater than the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm is issued and the test is stopped;

[0016] ⑤Nominal flow working performance, air tightness and torque change test: liquid nitrogen is supplied to the low temperature valve to be tested through the gas inlet pipe, and after the nominal flow stabilizes, the electromagnetic valve is closed, the torque, surface temperature, nitrogen concentration and test number of the low temperature valve to be tested are collected and counted by the control host PLC, when a process is completed, the cycle is restarted, and when the torque is greater than the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm is issued and the test is stopped;

[0017] ⑥5-30% nominal flow working performance, air tightness and torque change test: liquid nitrogen is supplied to the low temperature valve to be tested through the gas inlet pipe, and after the low flow stabilizes, the electromagnetic valve is closed, the torque, surface temperature, nitrogen concentration and test number of the low temperature valve to be tested are collected and counted by the control host PLC, when a process is completed, the cycle is restarted, and when the torque is greater than the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm is issued and the test is stopped;

[0018] ⑦Obtain quantitative adaptability and performance change curve: the running frequency under the air tightness performance condition is taken as the probability density, the life reliability of the low temperature valve is evaluated, the different flow and torque change curves are established, and the performance failure trend of the low temperature valve is comprehensively evaluated.

[0019] The present application has the following advantages and positive effects:

[0020] 1、The device of the present application is based on the dynamic driving device in the system, adjusts the valve time, forms different low temperature working time under the conditions of low temperature working condition, running frequency and gas running condition, and through the nitrogen concentration sensor on the low temperature valve tool and the valve torque, flow monitoring system of the test device system, the quantitative adaptability and performance change curve are obtained.

[0021] 2、The test method provided by the application adjusts the operation condition of the to-be-tested cryogenic valve test piece, tests the torque performance and air tightness of the cryogenic valve under maximum flow, nominal flow and lower flow, quantitatively evaluates the failure performance change, and comprehensively evaluates the life reliability of the cryogenic valve for LNG under the low-temperature operation condition.

[0022] 3、The test method provided by the application takes the opening time of the electromagnetic valve as a state option, takes the torque change value or the nitrogen concentration detection value as a threshold value, and constructs a process of the test, and finally completes the information collection and statistics of the specific values of process stress and strain, temperature, test times and the like through the control host. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a functional composition schematic diagram of the performance failure test device of the cryogenic valve for LNG.

[0024] Figure 2 It is a PLC control flow chart of the control host.

[0025] Among them: 1-liquid nitrogen storage tank; 2-hand valve; 3-electromagnetic valve; 4-closed box; 5-PLC control host; 6-temperature and nitrogen concentration sensor; 7-driving mechanism; 8-cryogenic valve test station. DETAILED DESCRIPTION

[0026] Referring to Figure 1 , 2 , a performance failure test device of a cryogenic valve for LNG, comprising a medium gas source supply system, a closed box and a cryogenic valve test station.

[0027] The cryogenic valve test station is located in the closed box, a driving mechanism and a to-be-tested cryogenic valve connected thereto are installed on the cryogenic valve test station, and the driving mechanism is composed of a torque and displacement sensor and a servo motor connected thereto. More than 3 groups of nitrogen concentration sensors and temperature sensors are installed on the upper part, the middle part and the bottom part of one side wall of the closed box, and a gas outlet pipe is installed on the other side wall.

[0028] The medium gas source supply system comprises a liquid nitrogen storage tank, a liquid nitrogen gas supply main pipe and a plurality of branch distribution pipes, wherein the inlet of the liquid nitrogen gas supply main pipe is connected with the liquid nitrogen storage tank and a hand valve is installed on the liquid nitrogen gas supply main pipe, the outlet of the liquid nitrogen gas supply main pipe is connected with the plurality of branch distribution pipes, a valve and an electromagnetic valve are installed on each branch distribution pipe, and the outlet of the electromagnetic valve is connected with the to-be-tested cryogenic valve through an inlet pipe. The raw material gas supply main pipe and the plurality of branch distribution pipes are pipelines composed of metal pipes with a diameter ≤200 mm. The inlet pipe connected with the outlet of the electromagnetic valve is a pipeline composed of metal pipes with a diameter ≤150 mm.

[0029] The electromagnetic valve on each branch distribution pipe, the nitrogen concentration sensor and the temperature sensor on the closed box, and the driving mechanism on the low temperature valve test station are connected with the control host PLC through data / signal transmission lines, wherein the electromagnetic valve is connected with the control host PLC through the data / signal transmission lines to complete the control of the opening and closing time of the electromagnetic valve, so as to control the flow and working time of the supplied medium.

[0030] The test method of the above LNG low temperature valve performance failure test device includes the following steps:

[0031] ① Install the low temperature valve to be tested, the nitrogen concentration sensor and the temperature sensor: place one or more low temperature valves to be tested on the low temperature valve test station, place the low temperature valve test station in the closed box, connect the gas inlet of the low temperature valve to be tested to the corresponding LNG gas supply pipe, and connect the gas outlet to the corresponding gas outlet pipe on the side wall of the closed box. Install the nitrogen concentration sensor and the temperature sensor on the upper, middle and lower parts of the side wall of the closed box;

[0032] ② Start the medium gas source supply system to supply internal medium liquid nitrogen to the low temperature valve to be tested to simulate the actual running state;

[0033] ③ Initial temperature change and corresponding time test: when the test starts, first open the electromagnetic valve, observe the diffusion of liquid nitrogen in the closed box, and correspond to the temperature of the outer surface of the closed box collected by the temperature sensor and transmitted to the control host PLC, to obtain a series of temperature and time changes of the collected points of the temperature sensor, and determine the time of the low temperature valve to be tested under the stable state of the external temperature under the conditions of maximum flow, nominal flow and 5-30% nominal flow;

[0034] ④ Perform maximum flow working performance, air tightness and torque change test:

[0035] According to the flow, temperature and time corresponding relationship obtained in step ③, take the maximum flow Q1 as an example, determine the corresponding electromagnetic valve opening time t1, and use it as the running working time to perform a cycle test. First, set the electromagnetic valve opening time to t1, the working frequency number n1, the torque initial performance k 11 , and the nitrogen initial concentration k 12 When the opening time reaches t1, the control host PLC closes the electromagnetic valve, the driving mechanism in the low temperature valve test station operates, and the opening and closing of the valve are executed. Record the working frequency 1 time, the torque performance and calculate the arithmetic mean of the 3 groups of nitrogen concentration. Repeat the above steps when the working frequency number n1 reaches 10000 times or the stress, torque performance changes by 10% or the nitrogen concentration changes by 5%, and end the test;

[0036] ⑤ Perform nominal flow working performance, air tightness and torque change test:

[0037] According to the flow, temperature and time corresponding relationship obtained in step ③, taking the nominal flow Q2 as an example, the corresponding electromagnetic valve opening time t2 is determined, and the electromagnetic valve opening time t2 is taken as the running working time to perform the cycle test. First, the control host PLC is set to the electromagnetic valve opening time t2, the working frequency times n2, the torque initial performance k 21 , the nitrogen initial concentration k 22 When the opening time reaches t1, the control host PLC closes the electromagnetic valve, the driving mechanism in the low-temperature valve test station is actuated, the opening and closing valve actions are performed, the working frequency 1 times, the torque performance and the arithmetic mean of the three groups of nitrogen concentration are recorded and analyzed. The above steps are repeated, and when the working frequency times n2 reaches 10000 times or the stress, torque performance changes by 10% or the nitrogen concentration changes by 5%, the test is ended;

[0038] ⑥ Perform the working performance, air tightness and torque change test of 20% nominal flow:

[0039] According to the flow, temperature and time corresponding relationship obtained in step ③, taking the nominal flow Q2 as an example, the corresponding electromagnetic valve opening time t2 is determined, and the electromagnetic valve opening time t2 is taken as the running working time to perform the cycle test. First, the control host PLC is set to the electromagnetic valve opening time t3, the working frequency times n3, the torque initial performance k 31 , the nitrogen initial concentration k 32 When the opening time reaches t3, the control host PLC closes the electromagnetic valve, the driving mechanism in the low-temperature valve test station is actuated, the opening and closing valve actions are performed, the working frequency 1 times, the torque performance and the arithmetic mean of the three groups of nitrogen concentration are recorded and analyzed. The above steps are repeated, and when the working frequency times n3 reaches 10000 times or the stress, torque performance changes by 10% or the nitrogen concentration changes by 5%, the test is ended;

[0040] ⑦ Obtain the quantitative adaptability and performance change curve:

[0041] The running times under the air tightness performance condition are taken as the probability density, the life reliability of the low-temperature valve is evaluated, the different flow and torque change curves are established, and the performance failure trend of the low-temperature valve is comprehensively evaluated.

[0042] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A test method based on a performance failure testing device for cryogenic valves used in LNG, characterized in that: This testing method is applicable to a performance failure testing device for cryogenic valves used in LNG. The device includes a medium gas supply system, a sealed enclosure, and a cryogenic valve testing station. The cryogenic valve testing station is located inside the sealed enclosure. A drive mechanism and the cryogenic valve to be tested are installed at the testing station. A nitrogen concentration sensor, a temperature sensor, and an outlet pipe are installed on the side wall of the sealed enclosure. The medium gas supply system includes a raw material storage tank, a raw material gas supply main pipe, and multiple branch distribution pipes. The inlet of the raw material gas supply main pipe is connected to the raw material storage tank and a manual valve is installed thereon. The outlet of the raw material gas supply main pipe is connected to the multiple branch distribution pipes. Each branch distribution pipe is equipped with a valve and a solenoid valve, and the outlet of the solenoid valve is connected to the cryogenic valve to be tested via an inlet pipe. The solenoid valves on each branch distribution pipe, the nitrogen concentration sensor and temperature sensor on the sealed enclosure, and the drive mechanism on the cryogenic valve testing station are all connected to a control host PLC via data / signal transmission lines. The testing method of this device includes the following steps: ① Install the cryogenic valve to be tested, nitrogen concentration sensor, and temperature sensor: Place one or more cryogenic valves to be tested on the cryogenic valve testing station, and test the cryogenic valves... The work position is located inside the sealed box. The inlet of the cryogenic valve to be tested is connected to the corresponding LNG supply pipe, and the outlet is connected to the corresponding outlet pipe on the side wall of the sealed box. Nitrogen concentration sensor and temperature sensor are installed on the upper, middle and lower parts of one side wall of the sealed box, respectively. ② Start the medium gas supply system to supply the internal medium to the cryogenic valve under test to simulate the actual operating state; ③ Initial temperature change and corresponding time test: At the beginning of the test, the solenoid valve is opened first, and the situation of liquid nitrogen being released in the closed box is observed. The temperature of the outer surface of the closed box is compared with the temperature collected by the temperature sensor and transmitted to the control host PLC. The temperature and time changes of a series of temperature sensor collection points are obtained, and the time of the external temperature of the tested low temperature valve under the maximum flow rate, nominal flow rate and 5-30% nominal flow rate is determined. ④ Perform maximum flow rate performance, airtightness and torque variation tests: Supply liquid nitrogen to the cryogenic valve under test through the inlet pipe. After the maximum flow rate stabilizes, close the solenoid valve. Collect and statistically analyze the torque, surface temperature, nitrogen concentration and test count of the cryogenic valve under test through the control host PLC. When a process is completed, restart the cycle. When the torque is greater than the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm is issued and the test is stopped. ⑤ Conduct nominal flow rate performance, airtightness and torque change tests: Supply liquid nitrogen to the cryogenic valve under test through the air inlet pipe. After the nominal flow rate stabilizes, close the solenoid valve. Collect and statistically analyze the torque, surface temperature, nitrogen concentration and test number of the cryogenic valve under test through the control host PLC. When a process is completed, the cycle starts again. When the torque is greater than the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm is issued and the test stops. ⑥ Conduct performance, airtightness, and torque variation tests at 5-30% nominal flow rate: Supply liquid nitrogen to the cryogenic valve under test through the inlet pipe. After the flow rate stabilizes at a low level, close the solenoid valve. Collect and statistically analyze the torque, surface temperature, nitrogen concentration, and number of tests of the cryogenic valve under test through the control host PLC. After one cycle is completed, restart the cycle. When the torque exceeds the set threshold or the nitrogen concentration exceeds the initial value by 5%, an alarm will be issued and the test will stop. ⑦ Obtain quantified adaptability and its performance change curves: under airtight performance conditions The number of operations is used as the probability density to evaluate the life reliability of cryogenic valves. Curves of different flow rates and torque changes are established to comprehensively evaluate the performance failure trend of cryogenic valves.

2. The test method based on the performance failure test device for cryogenic valves for LNG according to claim 1, characterized in that: The drive mechanism consists of torque and displacement sensors and a servo motor connected to them.

3. The test method based on the performance failure test device for cryogenic valves for LNG according to claim 1, characterized in that: ≥3 sets of nitrogen concentration sensors and temperature sensors are installed on the upper, middle and bottom of one side wall of the enclosed box.

4. The test method based on the performance failure test device for cryogenic valves for LNG according to claim 1, characterized in that: The main gas supply pipe and the multi-branch distribution pipe are made of metal pipes with a diameter of ≤200 mm.

5. The test method based on the performance failure test device for cryogenic valves for LNG according to claim 1, characterized in that: The air inlet pipe connected to the outlet of the solenoid valve is a pipe made of metal tubing with a diameter of ≤ 150 mm.

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