A system for preparing simulated lunar soil with known water content and h isotope

Abstract

The present invention discloses a system for preparing simulated lunar soil with low water content and known H isotopes. The system comprises a standard water source sample tube, a vaporization line, a sample chamber, a vacuum line, and a dry nitrogen line. The standard water source sample tube is connected to the inlet side of the sample chamber via the vaporization line, and the outlet side of the sample chamber is connected to the vacuum line for evacuating the chamber to a set vacuum level. The vaporization line includes a temperature-controlled buffer chamber, a first line, a mixing chamber, and a second line for suppressing low vacuum and H isotope fractionation. A first pressure gauge is provided on the inlet side of the sample chamber, and a second pressure gauge is provided on the outlet side of the sample chamber. The vapor-soil combination process is determined to be complete when the pressures in the pipelines monitoring the inlet and outlet sides of the sample chamber stabilize. The present invention is capable of preparing simulated lunar soil with low water content and known H isotopes.

Description

TECHNICAL FIELD

[0001] The application relates to a low-water-content and H-isotope-known simulated lunar soil preparation system. BACKGROUND

[0002] Real lunar soil is rare and difficult to obtain, and cannot meet the engineering needs. In actual engineering, simulated lunar soil is generally used to replace real lunar soil for relevant research.

[0003] The water ice research of lunar soil in the permanent shadow area near the lunar poles is an important detection content. The detection of the isotope ratio of D / H of lunar water ice can reveal the main source and evolution process of lunar water ice. Is the water ice in the lunar permanent shadow area mainly original or from late injection? Is it caused by solar wind proton injection or comet or meteorite impact? These information has important academic value.

[0004] Some experiments have been conducted at home and abroad to simulate the properties of ice weathering layer simulant, such as preparing a water-containing Martian weathering layer simulant frozen by water vapor diffusion to prepare the thermal properties of the water-containing Martian weathering layer simulant; using a manual pump sprayer and a cement mixer to prepare water-containing lunar soil, and preparing water-containing simulated lunar soil with a water content of 1.78% to 11.9%; using a peristaltic pump to pump a premix similar to "mud" into a low-temperature container to prepare water-containing lunar soil; using a steel skeleton cage, a semi-permeable cloth and a water droplet disperser to prepare simulated lunar soil with a water content of 1% to 14%. The water content of the samples prepared by these methods is very high, and they are not suitable for simulated lunar soil containing large particles.

[0005] Chinese patent document CN116223142A discloses a vacuum drying water molecule gas deposition water-containing simulated lunar soil preparation and transfer composite device, which solves the problem that traditional lunar soil preparation process cannot exclude the interference of impurity gas, and improves the accuracy of the preparation water content, but fails to give the isotopic abundance standard. There is no preparation method for H-isotope-known low-water-content simulated lunar soil combined with the soil. SUMMARY

[0006] The application aims to provide a low-water-content and H-isotope-known simulated lunar soil preparation system to prepare H-isotope-known low-water-content simulated lunar soil combined with the soil.

[0007] To this end, the application provides a low water content and H isotope known simulated lunar soil preparation system, comprising: a standard water source sample pipe, a vaporization pipeline, a sample chamber, a vacuum pipeline, a dry nitrogen pipeline, the standard water source sample pipe is connected with the gas inlet side of the sample chamber through the vaporization pipeline, the gas outlet side of the sample chamber is connected with the vacuum pipeline, and the vacuum pipeline is used for vacuumizing to a set vacuum degree, the vaporization pipeline comprises a temperature-controlled buffer chamber, a first pipeline, a mixing chamber and a second pipeline, so as to inhibit the adsorption of water vapor and H isotope fractionation on the pipe wall; the dry nitrogen pipeline comprises a nitrogen cylinder, a mass flow meter, a third pipeline and a fourth pipeline, the nitrogen cylinder is connected with the mixing chamber through the third pipeline, and the nitrogen cylinder is connected with the sample chamber through the fourth pipeline; the gas inlet side of the sample chamber is provided with a pressure gauge one, and the gas outlet side of the sample chamber is provided with a pressure gauge two, and when the readings of the pressure gauge one and the pressure gauge two are stable during the preparation of the simulated lunar soil, it is determined that the simulated lunar soil combination process is completed.

[0008] The simulated lunar soil preparation system according to the application can prepare simulated lunar soil with low water content and known H isotope.

[0009] In addition to the purposes, features and advantages described above, the application has other purposes, features and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0010] The drawings accompanying the specification of this application serve to provide further understanding of the application, and the illustrative embodiments of the application and their descriptions serve to explain the application, and do not constitute improper limitations on the application. In the drawings:

[0011] Figure 1 is a structural diagram of the low water content and H isotope known simulated lunar soil preparation system of the application;

[0012] Figure 2 is an operation flow diagram of the low water content and H isotope known simulated lunar soil preparation system of the application;

[0013] Figure 3 is a structural diagram of the sample chamber of the application;

[0014] Figure 4 is a diagram of the simulated lunar soil combination in the sample chamber of the application;

[0015] Figure 5 shows the water content detection results of the simulated lunar soil in a combined state prepared according to the method of the application;

[0016] Figure 6 shows the standard deviation results of the water content of the same layer samples of the four groups of tests of the application;

[0017] Figure 7 and Figure 8Two sets of sample H isotope measurement results of the present application are shown. DETAILED DESCRIPTION

[0018] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0019] To realize the preparation of low water content and H isotope simulated lunar soil and verify the feasibility of the method, the present application includes three parts.

[0020] I. Preparation of standard hydrogen isotope water sample

[0021] In the present application, four sample waters were prepared using standard substances, and then tested and calibrated using a water vapor isotope analyzer. The results are shown in the following table.

[0022] Table 1, standard value and expanded uncertainty of standard substance value element δD, and measurement results of deuterium value of prepared water sample

[0023]

[0024] II. Preparation system of low water content and H isotope known simulated lunar soil

[0025] In combination with reference Figure 2 The present preparation system mainly includes a standard water source, a buffer chamber, a mixing chamber, a cold trap collection system, a sample chamber, a dry nitrogen system, a temperature control system, a pressure monitoring system, a vacuum system, and related pipeline components and valves.

[0026] The standard water source used in the experiment is the calibrated nominal value isotope sample in Table 1.

[0027] Due to the adsorption characteristics of water molecules, even in an ultra-low pressure state, the inner surface of the stainless steel will still adsorb a large number of water molecules, and even accumulate in the pipeline. Adsorption or condensation will cause phase change of water. Therefore, a buffer chamber is added between the standard water source and the lunar soil sample, the temperature of the entire system chamber and pipeline is controlled, and nitrogen gas is mixed with water vapor outlet gas through molecular collision. The nitrogen gas and water vapor outlet gas both use 1 / 4 inch pipes.

[0028] The temperature control system is composed of a glass fiber heating belt, a K-type patch thermocouple, and a transmitter.

[0029] The sample chamber is a KF40 stainless steel pipe with a length of 5 cm, which is connected by a clamp, facilitating length adjustment and segmented sampling.

[0030] Pressure monitoring is monitored by two PuFa pressure gauges on the sample filling barrel, with a full-range pressure gauge at the upper end and a low-pressure (1330 Pa) pressure gauge at the lower end.

[0031] In combination with reference Figure 3The preparation process of the preparation method is as follows.

[0032] Before the preparation of the formal experiment, the pipeline temperature control system is started to preheat the vaporization pipeline, and the temperature is stabilized at 60°C, so as to ensure that the standard water source is vaporized, and isotopic fractionation is not generated between the liquid phase and the gas phase, and water vapor with a known isotopic composition is generated within a certain concentration range.

[0033] The system is confirmed to have a leakage rate of less than 1*10-9 Pa.m / s by using a helium leak detector, and is considered to have good vacuum degree. 3 / s, and is considered to have good vacuum degree. The nitrogen flow control valve and the vacuum system are opened, all valves are opened, and the system is purged for 1 hour by using dry nitrogen.

[0034] The nitrogen flow control valve and the vacuum system are closed, valves 2, 5 and 6 are closed, the baffle valve is closed, the sealed lunar soil sample chamber is removed, valve 1 is closed, and the KF25 clamp is opened to remove the standard water source sample pipe.

[0035] The removed lunar soil sample chamber and the standard water source sample pipe are transferred to a water-free nitrogen atmosphere glove box for sampling.

[0036] The particle size parameters of the simulated lunar soil dry soil sample are typical working condition particle size distribution parameters. When the dry soil sample is sampled, the sample is dry, and most of the particles are tens of microns, so electrostatic and dust are controlled, and the sealing degree of the phenyl silicone rubber sealing ring and the valve is ensured.

[0037] In order to ensure the uniformity and compaction fidelity of the particle size gradation mixing, the sample is naturally dropped during sampling, and does not need to be vibrated or compacted.

[0038] After the sample is sampled in the glove box, the baffle valve of the lunar soil sample chamber is closed, valve 1 of the standard water source sample pipe is closed, and they are transferred from the glove box, and then they are connected to the original system through the baffle valve and the KF25 clamp. Close valves 4 and 5, open the vacuum system, and open other valves to vacuum the residual air in the pipeline, the pores in the lunar soil sample chamber and the standard water source sample pipe.

[0039] Close the vacuum system, close valve 1, use a liquid nitrogen barrel to make the standard water source sample freeze for 15 minutes to prevent sublimation, keep valves 4 and 5 closed, open other valves, and open the vacuum system to vacuum the system.

[0040] After the pressure gauge two displays a value less than 10 Pa, the vacuum system is closed, valve 3 is closed, valve 1 is opened, and a hollow heating pipe is used to continuously heat for about 10 minutes, so that the standard water source sample is completely vaporized in the buffer chamber.

[0041] Open the vacuum system, open valve 3, vaporized standard water source into the mixing chamber, control the suction speed of the vacuum system pump end, mix for about 15 minutes, then observe the readings of the two pressure gauges, when the two readings are almost stable, the vapor soil combination reaches adsorption equilibrium, and the preparation is completed.

[0042] From the reading of the upper pressure gauge, it is determined whether the test is terminated due to the depletion of the water source, and the continuous vacuum extraction is prevented from causing the water vapor in the sample to be extracted.

[0043] During preparation, the standard water source isotope sample uses GBW04458, the temperature is controlled at 58-62℃, and the pumping time is controlled at about 15-20 minutes.

[0044] After preparation, the sample chamber is removed and sealed for transfer to the anhydrous glove box for rapid layered sampling, shaking and mixing. Then the sample is packed into the water content sample tube and the isotope sample tube for subsequent testing of the water content and δD value of the prepared vapor soil.

[0045] Three, water content and H isotope test results and analysis

[0046] Water content test results

[0047] Four groups of tests were conducted on water content using a Karl Fischer moisture meter, and the size of the lunar soil sample chamber was controlled to be five straight tubes each time, as shown in Figure 3 The schematic of vapor soil combination is shown in Figure 4 In Figure 3 and Figure 4 , a sealing gasket 2 is provided between adjacent straight tubes 1, and the straight tubes 1 are filled with lunar soil 3, and the water vapor path 4 passes through the lunar soil 3 to realize vapor soil combination.

[0048] The amount of water used in each test was 30 ml, and when sampling and testing the water content, the samples were taken from top to bottom with the depth labels being 1, 2, 3, 4, and 5, with the topmost being No. 1 and the bottommost being No. 5. The water content test results are shown in Figure 5 .

[0049] For the four groups of tests, the water content values of the same layer samples obtained in each test were analyzed for deviation, and the results are shown in Figure 6 .

[0050] From the Figure 6It can be seen that the standard deviation of the moisture content of the same layer samples obtained by the four groups of tests is less than 0.1%, the consistency is good, and the moisture content of the obtained samples is less than 1wt%. It can be seen that by controlling the time, water sample amount, pressure difference, pumping speed and other influencing factors of each test, the low moisture content of the steam-soil combined state of the simulated lunar soil with good consistency can be obtained. And from the depth point of view, the overall moisture content distribution in the sample chamber is first decreased and then increased from top to bottom.

[0051] Hydrogen isotope relative abundance δD measurement results

[0052] The measurement of hydrogen isotope relative abundance δD uses a liquid water isotope analyzer (model GLA431-TLWIA). A total of two groups of 10 samples were tested for isotopes, and the test results are shown in Figure 7 and Figure 8 The horizontal coordinate in the figure is δD (unit: ‰), and the vertical coordinate represents the number of layers. It can be seen from Figure 7 and Figure 8 that the trends of the two groups of test results are basically the same, and the δD range is-58.44‰-1.90‰, which is less than the original water sample value 8.3‰.

[0053] Because the lighter H2O in the first and second layer pores is continuously desorbed from the lunar soil particle surface into the mobile phase; the bottom layer pore outlet flow capacity is limited, and the hydrogen isotope relative abundance δD results of the third and fourth layers are close to the original value 8.3‰, so the two layers are taken as effective steam-soil.

[0054] The simulated lunar soil of the present application has two characteristics of low moisture content and standard isotope steam-soil combination. The standard low moisture content of the simulated lunar soil faces the detection limit of the load instrument to determine the lower limit of the measurement of the load instrument; the sample with the standard isotope value faces the ground calibration of the load instrument to determine the measurement error of the load instrument.

[0055] The above only describes the embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A system for preparing simulated lunar soil with low water content and known H isotopes, characterized in that: include: Standard water source sample tube, vaporization pipeline, sample chamber, vacuum pipeline, dry nitrogen pipeline, The standard water source sample tube is connected to the air inlet side of the sample chamber through a vaporization pipeline, and the air outlet side of the sample chamber is connected to a vacuum pipeline for evacuating to a set vacuum degree. The vaporization pipeline includes a temperature-controlled buffer chamber, a first pipeline, a mixing chamber, and a second pipeline to suppress water vapor adsorption on the tube wall and H isotope fractionation; The dry nitrogen pipeline includes a nitrogen bottle, a mass flow meter, a third pipeline and a fourth pipeline, the nitrogen bottle is connected to the mixing chamber through the third pipeline, and the nitrogen bottle is connected to the sample chamber through the fourth pipeline; The sample chamber is provided with a pressure gauge 1 on the air inlet side and a pressure gauge 2 on the air outlet side. During the steam-soil preparation process, the steam-soil combination process is concluded when the readings of the pressure gauge 1 and the pressure gauge 2 are stable. The vaporization pipeline also includes a temperature control system, which includes a glass fiber heating belt, a K-type patch thermocouple and a transmitter, and is used to heat, control and detect the temperature of the vaporization pipeline. The standard water source sample is a calibrated nominal value isotope sample.

2. The system for preparing simulated lunar soil with low water content and known H isotopes according to claim 1, characterized in that: The temperature of the vaporization pipeline is controlled to 58-62°C.

3. The system for preparing simulated lunar soil with low water content and known H isotopes according to claim 1, characterized in that: The standard water source sample tube is provided with a valve, and the standard water source sample tube is connected to the system through a clamp. The system also includes a liquid nitrogen tank for subjecting the standard water source sample tube to a liquid nitrogen bath to freeze the sample liquid and a hollow heating tube for continuously heating the standard water source sample tube to vaporize the sample liquid.

4. The system for preparing simulated lunar soil with low water content and known H isotopes according to claim 1, characterized in that: The vacuum pipeline is provided with a filter and a vacuum pump. When the indications of the first and second pressure gauges are stable, it is determined that the steam-soil combination process is completed.

5. The system for preparing simulated lunar soil with low water content and known H isotopes according to claim 1, characterized in that: The sample chamber comprises a plurality of straight-through pipes, and adjacent straight-through pipes are connected by clamps. The air inlet side and the air outlet side of the sample chamber are respectively provided with baffle valves.

6. The system for preparing simulated lunar soil with low water content and known H isotopes according to claim 1, characterized in that: The preparation process of the preparation system is as follows: S1. Connect the unloaded sample chamber and the standard water source sample tube to the system, heat the vaporization line, and evacuate and degas. S2. After leak testing the system pipeline, remove the sample chamber and standard water source sample tube from the system and move them to the glove box for sample loading; S3. Load the standard water source and dry soil samples separately and connect them to the system. Place the standard water source sample tube in a liquid nitrogen bath for 15 minutes before connecting it to the vaporization line to freeze the standard water source and prevent sublimation. Purge the air from the system pipes and then use a hollow heating tube to completely vaporize the standard water source sample into the buffer chamber to prevent H isotope fractionation. S4. Control the pumping speed of the vacuum pump until the readings of the two pressure gauges are basically stable. At this time, the steam-soil preparation is completed. S5. Disassemble the sample chamber from the system and transfer it to the glove box to package the samples.

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