Device and method for testing specific heat capacity of corrosive salt solution

Abstract

The invention belongs to the technical field of liquid thermophysical property testing, and particularly relates to a corrosive salt solution specific heat capacity testing device and method. The device comprises a to-be-measured sample box, a temperature measuring probe, a calorimeter and a heat insulation screen, the to-be-tested sample box is used for placing a to-be-tested sample, and the temperature measuring probe is arranged in the to-be-tested sample box; the to-be-detected sample box is made of platinum-iridium alloy; a calorimeter is arranged on the outer side of the to-be-tested sample box, the heat insulation screen is sleeved on the outer side of the calorimeter, and a thermocouple is arranged between the heat insulation screen and the calorimeter. The specific heat capacity of liquid substances within the range of 278-353 K can be tested by adopting a heat insulation method, the sample cylinder is particularly suitable for testing the specific heat capacity of corrosive solutions, the corrosion rate of the corrosive solutions such as chlorine salt to the sample cylinder is smaller than or equal to 0.05 mm / a, and the sample cylinder made of platinum-iridium alloy is suitable for testing the specific heat capacity of strong corrosive liquids such as strong acid and strong alkali.

Description

Technical Field

[0001] The present application belongs to the technical field of liquid thermal property testing, and specifically relates to a device and method for testing the specific heat capacity of a corrosive salt solution. Background Art

[0002] The specific heat capacity of a liquid is an important indicator for measuring the thermodynamic properties of a liquid and has important applications in industry. The measurement of the specific heat capacity of a substance plays an important role in understanding the structure of the substance, determining the phase change of the substance, identifying the purity of the substance, and developing new energy and new materials. In the study of chemical thermodynamics of solutions, the most important role of specific heat capacity is to derive the apparent molar heat capacity of the solute, thereby indicating the effect of the introduction of the solute on the properties of the solution. Using the apparent molar heat capacity data of the solution, especially the dilute solution, the standard state thermodynamic properties of the ion can be obtained, and then the effect of temperature on the thermodynamic properties of different processes in the solution can be clarified.

[0003] Experiment is one of the important ways to obtain specific heat capacity data. Currently, the more commonly used methods include adiabatic method, flow method, differential scanning calorimetry, etc. The existing measurement methods have the following main disadvantages: (1) The measurement principle is relatively complex, involving many technical means, many physical quantities that need to be measured, and a large amount of calculation in the later stage, which makes it difficult for operators and learners to understand. (2) In the experimental measurement results, the heat absorbed by the inner cylinder of the calorimeter, the agitator, the heating resistor wire, the thermometer and other materials needs to be calculated in turn. The mass of the inner cylinder, the agitator, the heating resistor wire, etc. needs to be measured separately, and the volume of the thermometer immersed in the liquid and other parameters need to be measured. The calculation amount is large. In addition, cross-calculations will further increase the error of the experimental measurement results. (3) The existing liquid specific heat capacity measuring instrument has a large uncertainty in the measurement results because the heat dissipated to the environment cannot be measured.

[0004] At present, the corresponding liquid specific heat measurement instruments are not very mature, and have problems such as low measurement accuracy, poor repeatability and stability, and cannot meet the needs of industrial applications. In addition, the existing liquid specific heat capacity data are mostly the specific heat of a single solvent (such as water, ethanol, acetone, etc.) at room temperature, and the specific heat capacity data of solution systems with different temperature gradients and different concentration gradients are rarely reported. In particular, the existing equipment cannot meet the test requirements of the specific heat capacity of special media such as chlorine-containing solutions, hydrochloric acid, and nitric acid. Summary of the invention

[0005] The purpose of this application is to provide a device and method for testing the specific heat capacity of corrosive salt solutions, so as to solve the problem that the existing technology cannot meet the testing requirements of the specific heat capacity of special media such as chlorine-containing solutions, hydrochloric acid, nitric acid, etc.

[0006] Technical solution to achieve the purpose of this application:

[0007] In a first aspect, an embodiment of the present application provides a device for testing the specific heat capacity of a corrosive salt solution, the device comprising: a sample box to be tested, a temperature measuring probe, a calorimeter and a heat insulation screen;

[0008] The sample box to be tested is used to place the sample to be tested, and the temperature measuring probe is arranged in the sample box to be tested; the material of the sample box to be tested is platinum-iridium alloy;

[0009] A calorimeter is arranged outside the sample box to be tested, the heat insulation screen is sleeved outside the calorimeter, and a thermocouple is arranged between the heat insulation screen and the calorimeter.

[0010] Optionally, a calorimeter heating wire is arranged on the outside of the calorimeter, and an insulation shield heating wire is arranged on the outside of the insulation shield.

[0011] Optionally, the device further comprises: a constant temperature bath;

[0012] The constant temperature tank is sleeved on the outer side of the heat insulation screen, and is provided with a constant temperature water inlet and a constant temperature water outlet.

[0013] Optionally, the thermal insulation screen comprises: an inner thermal insulation screen and an outer thermal insulation screen;

[0014] The inner insulation screen is set on the outer side of the calorimeter, and an inner screen temperature difference thermocouple is arranged between the inner insulation screen and the calorimeter;

[0015] The outer insulation screen sleeve is arranged on the outer side of the inner insulation screen, and an outer screen temperature difference thermocouple is arranged between the outer insulation screen and the inner insulation screen.

[0016] Optionally, an inner insulation screen electric heating wire is arranged on the outer side of the inner insulation screen; an outer insulation screen electric heating wire is arranged on the outer side of the outer insulation screen.

[0017] Optionally, a groove for placing a temperature measuring probe is provided at the lower end of the sample box to be tested.

[0018] Optionally, a box cover is installed on the upper end of the sample box to be tested.

[0019] Optionally, the device further comprises: a temperature measuring probe seat;

[0020] The temperature measuring probe seat is arranged at the lower end of the sample box to be measured, and the temperature measuring probe is fixed on the temperature measuring probe seat.

[0021] A second aspect of the embodiment of the present application provides a method for testing the specific heat capacity of a corrosive salt solution, which is applied to any one of the devices for testing the specific heat capacity of a corrosive salt solution provided in the first aspect of the embodiment of the present application; the method comprises:

[0022] Placing the sample to be tested in the sample box;

[0023] The thermal insulation screen is heated to keep the sample box to be tested at a testing temperature;

[0024] Using a calorimeter to heat the sample to be tested;

[0025] The specific heat capacity of the sample to be tested at the detection temperature is determined according to the temperature rise of the sample to be tested and the electric energy consumed by the calorimeter.

[0026] Optionally, determining the specific heat capacity of the sample to be tested at the detection temperature according to the temperature rise of the sample to be tested and the electric energy consumed by the calorimeter specifically includes:

[0027] According to formula (4), the specific heat capacity C of the sample to be tested at the test temperature is determined P ;

[0028]

[0029] In the formula, Q e is the electric energy consumed by the calorimeter, C is the specific heat capacity of the sample box under test at the test temperature when it is empty, ΔT is the temperature rise of the sample under test, and m is the mass of the sample under test.

[0030] The beneficial technical effects of this application are:

[0031] The embodiment of the present application provides a device and method for testing the specific heat capacity of a corrosive salt solution. The device includes: a sample box to be tested, a temperature measuring probe, a calorimeter and an insulation screen; the sample box to be tested is used to place the sample to be tested, and the temperature measuring probe is arranged in the sample box to be tested; the material of the sample box to be tested is a platinum-iridium alloy; a calorimeter is arranged on the outside of the sample box to be tested, and the insulation screen is sleeved on the outside of the calorimeter, and a thermocouple is arranged between the insulation screen and the calorimeter. The embodiment of the present application adopts an adiabatic method to test the specific heat capacity of liquid substances in the range of 278-353K, and is particularly suitable for testing the specific heat capacity of corrosive solutions. The corrosion rate of corrosive solutions such as chloride salts on the sample tube is ≤0.05mm / a, and the sample tube made of platinum-iridium alloy is suitable for testing the specific heat capacity of highly corrosive liquids such as strong acids and strong alkalis. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a corrosive salt solution specific heat capacity testing device provided in an embodiment of the present application.

[0033] In the figure:

[0034] 1-constant temperature water inlet, 2-constant temperature bath, 3-external insulation screen heating wire, 4-external insulation screen, 5-external screen temperature difference thermocouple, 6-inner insulation screen heating wire, 7-inner screen temperature difference thermocouple, 8-inner insulation screen, 9-constant temperature water outlet, 10-test sample box, 11-test sample, 12-temperature measuring probe, 13-calorimeter heating wire, 14-calorimeter, 15-temperature measuring probe seat. DETAILED DESCRIPTION

[0035] In order to make those skilled in the art better understand the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, not all. Based on the embodiments recorded in the present application, all other embodiments obtained by those skilled in the art without paying creative work are within the scope of protection of the present application.

[0036] See also Figure 1 , which is a schematic diagram of the structure of a corrosive salt solution specific heat capacity testing device provided in an embodiment of the present application.

[0037] The embodiment of the present application provides a device for testing the specific heat capacity of a corrosive salt solution, comprising: a sample box 10 to be tested, a temperature measuring probe 12, a calorimeter 14 and a heat insulation screen;

[0038] The sample box 10 is used to place the sample 11 to be tested, and the temperature measuring probe 12 is arranged in the sample box 10 to be tested; the material of the sample box 10 to be tested is platinum-iridium alloy;

[0039] A calorimeter 14 is arranged outside the sample box 10 to be tested. The heat insulation screen is sleeved outside the calorimeter 14 . A thermocouple is arranged between the heat insulation screen and the calorimeter 14 .

[0040] It should be noted that chloride ions have a strong ability to corrode metal materials due to their small radius, strong penetrating ability, and strong adsorption on metal surfaces. The strong corrosion properties of chloride salts make it difficult to use specific heat capacity measurement devices for traditional materials (such as stainless steel, copper, aluminum, etc.). Platinum-iridium alloy has a strong resistance to chloride salt corrosion because the volatility and oxidizability of iridium significantly improves the corrosion resistance of platinum.

[0041] The embodiment of the present application relies on an insulating screen to control the insulating environment of the sample. The material of the sample box 10 to be tested is a platinum-iridium alloy, which is suitable for testing the specific heat capacity of highly corrosive liquids such as strong acids and strong alkalis.

[0042] In some possible implementations of the embodiments of the present application, a calorimeter heating wire 13 may be provided on the outside of the calorimeter 14, and an insulation shield heating wire is provided on the outside of the insulation shield to ensure that the sample 11 to be tested is at the required testing temperature.

[0043] In one example, in order to keep warm, the device may further include: a constant temperature bath 2;

[0044] The thermostatic tank 2 is sleeved on the outer side of the thermal insulation screen, and is provided with a constant temperature water inlet 1 and a constant temperature water outlet 9 .

[0045] In specific implementation, the medium added to the thermostat 2 can be selected according to the temperature range, such as pure water, alcohol, dimethyl silicone oil, etc. If the detection temperature is lower than the ambient temperature, the temperature of the thermostat 2 is set to be about 2-5°C lower than the experimental temperature; if the detection temperature is higher than the ambient temperature, the temperature of the thermostat 2 is set to be approximately equal to the experimental temperature.

[0046] In some possible implementations of the embodiments of the present application, the thermal insulation screen includes: an inner thermal insulation screen 8 and an outer thermal insulation screen 4;

[0047] The inner insulation shield 8 is sleeved on the outer side of the calorimeter 14, and an inner shield temperature difference thermocouple 7 is arranged between the inner insulation shield 8 and the calorimeter 14;

[0048] The outer insulation screen 4 is sleeved on the outer side of the inner insulation screen 8 , and an outer screen temperature difference thermocouple 5 is arranged between the outer insulation screen 4 and the inner insulation screen 8 .

[0049] In one example, the inner insulation shield electric heating wire 6 is arranged on the outer side of the inner insulation shield 8 ; and the outer insulation shield electric heating wire 3 is arranged on the outer side of the outer insulation shield 4 .

[0050] In some possible implementations of the embodiments of the present application, a groove for placing the temperature measuring probe 12 is provided at the lower end of the sample box 10 to be tested.

[0051] In one example, a box cover is installed on the upper end of the sample box 10 to be tested.

[0052] In some possible implementations of the embodiments of the present application, the device further includes: a temperature measuring probe seat 15;

[0053] The temperature measuring probe seat 15 is disposed at the lower end of the sample box 10 to be measured, and the temperature measuring probe 12 is fixed on the temperature measuring probe seat 15 .

[0054] The embodiment of the present application provides a device and method for testing the specific heat capacity of a corrosive salt solution. The device includes: a sample box to be tested, a temperature measuring probe, a calorimeter and an insulation screen; the sample box to be tested is used to place the sample to be tested, and the temperature measuring probe is arranged in the sample box to be tested; the material of the sample box to be tested is a platinum-iridium alloy; a calorimeter is arranged on the outside of the sample box to be tested, and the insulation screen is sleeved on the outside of the calorimeter, and a thermocouple is arranged between the insulation screen and the calorimeter. The embodiment of the present application adopts an adiabatic method to test the specific heat capacity of liquid substances in the range of 278-353K, and is particularly suitable for testing the specific heat capacity of corrosive solutions. The corrosion rate of corrosive solutions such as chloride salts on the sample tube is ≤0.05mm / a, and the sample tube made of platinum-iridium alloy is suitable for testing the specific heat capacity of highly corrosive liquids such as strong acids and strong alkalis.

[0055] Based on a corrosive salt solution specific heat capacity testing device provided in the above embodiment, an embodiment of the present application further provides a corrosive salt solution specific heat capacity testing method, which is applied to any one of the corrosive salt solution specific heat capacity testing devices provided in the above embodiment.

[0056] The present application provides a method for testing the specific heat capacity of a corrosive salt solution, comprising:

[0057] Step S101: placing the sample 11 to be tested in the sample box 10;

[0058] Step S102: heating the thermal insulation screen to keep the sample box 10 under the detection temperature;

[0059] Step S103: using the calorimeter 14 to heat the sample 11 to be tested;

[0060] Step S104: Determine the specific heat capacity of the sample 11 under test at the test temperature according to the temperature rise of the sample 11 under test and the electric energy consumed by the calorimeter 14.

[0061] It can be understood that according to the temperature rise ΔT of the LiCl solution to be tested in the sample tube, the total electric energy consumed by the temperature rise ΔT is calculated according to the following formula (1): e The specific heat capacity of the sample to be tested at the test temperature can be calculated by calculating according to formula (2) and the heat capacity C of the sample tube according to formula (3), that is, the following formula (4).

[0062] ΔT=T n -T c (1)

[0063] Q e =I×U×t (2)

[0064]

[0065]

[0066] Among them, ΔT, T n , T c They represent the temperature rise, final temperature and initial temperature of the sample to be tested respectively; Q e is the electric energy consumed by the calorimeter 14; I is the current passing through the calorimeter 14; U is the voltage across the calorimeter 14; t is the power-on time of the calorimeter 14; C is the specific heat capacity of the sample box 10 to be tested at the test temperature when it is unloaded; C p - specific heat capacity of the sample to be tested at the detection temperature; m is the mass of the sample to be tested 11.

[0067] Then, in one example, step S104 may specifically include:

[0068] According to formula (4), the specific heat capacity C of the sample 11 to be tested at the test temperature is determined as follows: P ;

[0069]

[0070] In the formula, Q e is the electric energy consumed by the calorimeter 14 , C is the specific heat capacity of the sample box 10 under no load at the detection temperature, ΔT is the temperature rise of the sample 11 under test, and m is the mass of the sample 11 under test.

[0071] The present application is described in detail above in conjunction with the accompanying drawings and embodiments, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present application. Any content not described in detail in the present application can adopt the existing technology.

Claims

1. A corrosive salt solution specific heat capacity testing device, characterized in that: The device comprises: a sample box to be tested (10), a temperature measuring probe (12), a calorimeter (14) and a heat insulation screen; The sample box (10) to be tested is used to place the sample (11) to be tested, and the temperature measuring probe (12) is arranged in the sample box (10) to be tested; the material of the sample box (10) to be tested is a platinum-iridium alloy; A calorimeter (14) is arranged outside the sample box (10) to be tested, the heat insulation screen is sleeved outside the calorimeter (14), and a thermocouple is arranged between the heat insulation screen and the calorimeter (14).

2. The corrosive salt solution specific heat capacity testing device according to claim 1, characterized in that: A calorimeter electric heating wire (13) is arranged on the outside of the calorimeter (14), and an insulation shield electric heating wire is arranged on the outside of the insulation shield.

3. The corrosive salt solution specific heat capacity testing device according to claim 1, characterized in that: The device further comprises: a constant temperature bath (2); The constant temperature tank (2) is sleeved on the outer side of the heat insulation screen and is provided with a constant temperature water inlet (1) and a constant temperature water outlet (9).

4. The corrosive salt solution specific heat capacity testing device according to claim 2, characterized in that: The thermal insulation screen comprises: an inner thermal insulation screen (8) and an outer thermal insulation screen (4); The inner insulation shield (8) is sleeved on the outer side of the calorimeter (14), and an inner shield temperature difference thermocouple (7) is arranged between the inner insulation shield (8) and the calorimeter (14); The outer insulation screen (4) is sleeved on the outer side of the inner insulation screen (8), and an outer screen temperature difference thermocouple (5) is arranged between the outer insulation screen (4) and the inner insulation screen (8).

5. The corrosive salt solution specific heat capacity testing device according to claim 4, characterized in that: The outer side of the inner heat insulation screen (8) is provided with an inner heat insulation screen electric heating wire (6); the outer side of the outer heat insulation screen (4) is provided with an outer heat insulation screen electric heating wire (3).

6. The device for testing specific heat capacity of corrosive salt solution according to any one of claims 1 to 5, characterized in that: The lower end of the sample box (10) to be tested is provided with a groove for accommodating a temperature measuring probe (12).

7. The corrosive salt solution specific heat capacity testing device according to claim 6, characterized in that: A box cover is installed on the upper end of the sample box (10) to be tested.

8. The device for testing specific heat capacity of corrosive salt solution according to any one of claims 1 to 5, characterized in that: The device further comprises: a temperature measuring probe seat (15); The temperature measuring probe seat (15) is arranged at the lower end of the sample box (10) to be measured, and the temperature measuring probe (12) is fixed on the temperature measuring probe seat (15).

9. A method for testing the specific heat capacity of a corrosive salt solution, characterized in that: A corrosive salt solution specific heat capacity testing device applied to any one of claims 1 to 7; the method comprising: Placing a sample to be tested (11) in a sample box to be tested (10); The heat insulation screen is heated so that the sample box (10) to be tested is at a testing temperature; Using a calorimeter (14) to heat the sample to be tested (11); The specific heat capacity of the sample (11) to be tested at the detection temperature is determined based on the temperature rise of the sample (11) to be tested and the electric energy consumed by the calorimeter (14).

10. The method for testing specific heat capacity of corrosive salt solution according to claim 9, characterized in that: Determining the specific heat capacity of the sample (11) to be tested at the detection temperature according to the temperature rise of the sample (11) to be tested and the electric energy consumed by the calorimeter (14) specifically includes: Determine the specific heat capacity C of the sample (11) to be tested at the test temperature according to formula (4): P ; In the formula, Q e is the electric energy consumed by the calorimeter (14), C is the specific heat capacity of the sample box (10) to be tested at the detection temperature when it is unloaded, ΔT is the temperature rise of the sample to be tested (11), and m is the mass of the sample to be tested (11).

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