JP2003344324A - Isopiestic specific heat measurement method and apparatus therefor for high pressure fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an isopiestic specific heat measurement method for a high pressure fluid implemented by using a simple structure which is a batch type sealed in a container and has the container accommodating a sample installed in a thermostatic chamber. <P>SOLUTION: A variable container 3 having a volume varied by external pressure is communicated with a sample container 1 through piping 2. The sample container 1 and the variable container 3 are installed in the thermostatic chamber 30. While a constant pressure is applied to the variable container 3, a thermal flow is externally supplied to the sample S in the sample container 1 and the temperature of the sample S is in a static state. In a cooling process, a thermal flow emitted to the thermostatic chamber is found from the temperature difference between the sample and the thermostatic chamber and a heat transfer coefficient, a thermal flow emitted from the sample container is found by using a standard sample, a thermal flow emitted from the sample is found from a difference between the thermal flow emitted to the thermostatic chamber and the thermal flow emitted from the sample container, and the thermal capacity of the sample is found from a summation of the thermal flow emitted from the sample and the temperature difference between the sample and the thermostatic chamber. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a constant pressure specific heat of a high-pressure fluid, and more particularly to a fluid and a mixed fluid such as a power plant and an air conditioning refrigerating machine, which requires a pressure vessel for the measuring apparatus. The present invention relates to a constant pressure specific heat measuring method and device for high pressure fluid.

[0002]

2. Description of the Related Art With the development of technology, the range of use of fluids is expanding to high temperature and high pressure regions. There are few devices that can measure the specific heat capacity and density under constant pressure conditions,
As a conventional specific heat capacity measuring method, there are a differential scanning method, an adiabatic method, a dropping method, a periodic heating method, a mixing method, a heat exchange method, a flow method and the like (for example, `` Thermophysical Property Handbook '' p. 561-565, Yokendo Publishing (1990)).

[0003]

At present, most of the analysis methods of the constant pressure specific heat measuring device are based on the adiabatic method. In the adiabatic method, the sample is completely insulated from the surroundings, and all the amount of heat supplied is used only for increasing the temperature of the sample, and the following basic formula is established.

Q = MC _p ΔT or as the heat flow rate, Q ′ = MC _p (dΔT / dt) where Q is the heat quantity, Q ′ is the heat flow rate, M is the mass of the sample, Δ
T is the temperature rise, C _p is the constant pressure specific heat of the sample, and t is the time.

The basic equation of this method is simple and easy to analyze. However, complete heat insulation means zero heat loss to the surroundings, which is very difficult to realize with a measuring device. The structure of the basic device is such that the vacuum around the sample causes almost no heat loss due to convective heat transfer.
I have to. Further, a reflection plate is provided on the inner wall of the heater or the sample container to make the heat loss due to heat radiation almost zero. In addition, in order to reduce the heat loss due to heat conduction, the lead wires of the heater and thermometer should be thin, the area for supporting the sample should be small, and the support should be a heat insulating material. A meter and a heater are attached to control the temperature difference between the sample and the place where there is heat loss to be 0, and this is dealt with. In order to realize the adiabatic method, the structure must be such that the heat loss due to the final heat conduction can be made zero.

Here, a high-pressure fluid is considered. First,
Since it is a fluid, it requires a container. If a normal pressure fluid is used, a thin sample container with a small heat capacity is used as a “sample + container” based on the above principle, and only the “container” is measured. It can be handled by subtracting "container" from ".

However, in the case of high-pressure fluid, a thick pressure vessel is required due to the pressure resistance design, and (1) the ratio of the heat capacity of the vessel to the sample becomes large,
Precision is not obtained. (2) The temperature distribution in the container becomes large, and the representative temperature cannot be obtained, resulting in large uncertainty. (3) It is more difficult to control than (2). (4) Since a pressure control pipe is required from the container, heat loss from the pipe is large, and the pipe is similarly thick, so (2),
Control is difficult as in (3). You must be careful about such points.

Another method is a differential scanning method. It is not necessary to perform adiabatic control because the reference container is used to add the amount of heat including heat loss and the difference in the amount of heat from the reference container is used for compensation, but it is not necessary to control the test container and the reference container. Since it is carried out, it is difficult to control the high-pressure fluid as in the adiabatic method.

In addition, the thermal relaxation method is used as a method for calculating the constant pressure specific heat by analyzing the heat loss from the data of the time-dependent change in the temperature difference without compensating the heat loss without intentionally performing adiabatic control. And is represented by the following basic formula.

Q '= MC _p (dΔT / dt) + αΔT where α is a heat transfer coefficient.

In this case, the heat loss to the surroundings is regarded as αΔT, and instead of performing adiabatic control, the surroundings may be placed in a constant temperature field. This constant temperature field can be easily realized by using a constant temperature bath.

However, although this method is often used for solids, it is considered that the influence of the heat transfer coefficient due to a pressure vessel or convection when a high-pressure fluid is targeted, and it is used for analysis targeting a fluid. Has not been done.

The batch system in which the container is filled with the sample has been described above. Most of the calorimeters on the market are of batch type, and many of them are of small size.

There is a type called a flow type in which a fluid is circulated in a pipe. In principle, the method is based on the adiabatic method or the differential scanning method and is the same as the batch method, but since the pressure can be easily controlled by the pump, the measurement along the isobar can be performed. The accuracy is good, and the measurement is performed with an error of about 1%. However, due to the large scale of the equipment and the long piping, there are many samples to be used and it is difficult to deal with it because there are many leaking places when handling dangerous substances. . Further, there is a pressure limit due to the performance of the pump and the like, and it can be said that the batch type is suitable for higher pressure.

The present invention has been made in view of the above problems of the prior art, and the object thereof is not a flow type so that a small amount of sample can be carried out, but a batch type closed in a container, and It is an object of the present invention to provide a constant pressure specific heat measuring method and device for high pressure fluid, which does not have a complicated structure for controlling inside and outside, and can be performed with a simple structure in which a container containing a sample is installed in a constant temperature bath. .

That is, the conventional thermal relaxation method for solids takes into consideration the effects of the specific pressure vessel and the effects of convection when targeting high-pressure fluid. This makes it possible to perform measurements along the isothermal line and isobar with a single filling, and especially for difficult-to-handle substances, it can be measured safely and in a short time, and the structure is simple. Maintenance is easy and the cost of manufacturing the device can be reduced.

[0017]

A method for measuring the constant pressure specific heat of a high-pressure fluid of the present invention which achieves the above object, comprises connecting a sample container of a predetermined volume and a variable container whose volume is variable by pressure from the outside by piping. The sample container and the variable container are installed in a constant temperature bath and a constant pressure is applied to the variable container, and a heat flow rate is externally supplied to the sample in the sample container to bring the temperature of the sample to a steady state. In the cooling process, the heat flow rate released to the constant temperature bath is determined from the temperature difference between the sample and the constant temperature bath and the heat passage coefficient, while the heat flow rate released from the sample container is determined using a standard sample. , The sum of the heat flow rates released from the determined sample, by determining the heat flow rate released from the sample from the difference between the heat flow rate released to the constant temperature bath and the heat flow rate released from the sample container And the temperature of the sample and the constant temperature bath at that time Determining the heat capacity of the sample from a method comprising.

In this case, it is desirable that the volume of the sample under a constant pressure state is obtained from the deformation amount of the variable container, the density of the sample is obtained from the volume, and the specific heat of the sample is obtained based on the obtained density. .

Further, it is desirable that the heat transfer coefficient is obtained from the result of making the temperature of the sample into a plurality of steady states by changing the heat flow rate supplied from the outside to the sample in the sample container.

The constant pressure specific heat measuring device for high pressure fluid of the present invention comprises:
A sample container for containing a fluid sample, a variable container communicated with the sample container by a pipe, and a pressure container containing the variable container are arranged in a temperature-controlled thermostatic chamber, and Means for setting and controlling the pressure in the space between the variable container and the pressure container to a predetermined value, means for detecting the amount of deformation of the variable container, and supplying a predetermined amount of thermal energy to the sample in the sample container And a temperature detecting means for detecting the temperature of the sample in the sample container, and a constant pressure is applied to the variable container, the sample in the sample container by the heating means. A heat flow rate is supplied to bring the temperature of the sample to a steady state, and the heat flow rate released to the constant temperature bath in the cooling process is determined from the temperature difference between the sample and the constant temperature bath and the heat passage coefficient, while using a standard sample. Released from the sample container The heat flow rate released from the sample is calculated from the difference between the heat flow rate released to the constant temperature bath and the heat flow rate released from the sample container. It is characterized in that the heat capacity of the sample is obtained from the total sum of the heat flow rates and the temperature difference between the sample and the constant temperature bath at that time.

In this case, examples of the variable container include a metal bellows, a container including a cylinder and a piston, and the like.

In the present invention, the sample is sealed in a container in a batch system, and the container containing the sample is placed in a constant temperature bath without a complicated structure for controlling the inside and outside of the sample. Due to the structure, the constant pressure specific heat capacity of the high-pressure fluid can be measured, and the measurement along the isothermal line and the isobar can be performed with one sample filling. Especially, there is toxicity that is difficult to handle. Since the sample (1) is also sealed, it can be measured safely and in a short time, the structure of the device is simple, the maintenance is easy, and the manufacturing cost can be reduced. Moreover, since it is possible to measure with a small amount of sample, it is suitable for an expensive and valuable sample that has just been developed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a constant pressure specific heat measuring device for high pressure fluid of the present invention comprises a calorimeter 10 for measuring a constant pressure specific heat capacity and a metal bellows volume meter 20 for measuring a density connected by a pipe 2. The calorimeter 10 and the metal bellows volume meter 20 are filled with a small amount of the sample S of a mass-adjusted fluid, and the expandable metal bellows 3 completely separates the sample S from the outside of the metal bellows 3. By pressurizing and controlling the gas G such as nitrogen gas as a pressure medium, the inside of the metal bellows 3 and the sample S of the calorimeter 10 can be pressurized and controlled to a high pressure region, and the calorimeter 10 and the metal can be controlled. Both the bellows volume meter 20 can be heated and controlled to a high temperature range by installing both in a constant temperature tank 30 using oil O such as silicon oil as a heat medium, and high temperature and high pressure can be achieved by filling a small amount of sample S once. In the area Is characterized in that can be measured in the number of state point.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a basic configuration of a constant pressure specific heat measuring device for high pressure fluid according to the present invention. This measuring device uses a fluid sample S
A sample container 1 for holding a sample and a metal bellows 3 connected to the sample container 1 by a pipe 2 which is thin and has negligible heat conduction
And a pressure vessel 4 containing a metal bellows 3 therein,
A pipe 5 for applying a predetermined pressure with the gas G from the outside to the metal bellows 3 in the pressure vessel 4 and measuring the pressure.
And the amount of movement of the tip of the metal bellows 3 is detected to detect the sample container 1
A volume meter 6 for measuring the volume of the fluid sample S filled in the pipe 2 and the metal bellows 3, and a pipe for filling the sample container 1, the pipe 2 and the metal bellows 3 with the sample S via the valve 8. 7, a heater 11 and a thermometer 12 arranged in the sample container 1, a liquid constant temperature tank 30 containing oil O as a heat medium therein, and an oil O in the liquid constant temperature tank 30.
It is provided with a heater 13, a thermometer 14, and a stirrer 15 arranged therein, and the calorimeter 10 includes a sample container 1 and a heater 11.
And the thermometer 12, the metal bellows volume meter 20
A liquid thermostatic chamber 30 that includes a metal bellows 3, a pressure vessel 4, and a volume meter 6, and is kept at a constant temperature for a long time.
Of the sample container 1, the pipe 2 and the pressure container 4 in the oil O of the heater 11 and the thermometer 12 in the sample container 1,
The volume meter 6, the pipe 5, the pipe 7, the heater 13, the thermometer 14, and the stirrer 15 in the liquid constant temperature tank 30 are connected to the outside of the liquid constant temperature tank 30 as shown in the drawing.

Using such a device, a constant pressure specific heat capacity,
The principle of calculating the density will be described. The mass of the sample S is measured by a mass method using a balance, filled in the sample container 1, the pipe 2 and the metal bellows 3 through the pipe 7 and the valve 8 and sealed by closing the valve 8. Calorimeter 1
0 and the metal bellows volume meter 20 are both installed in a constant temperature bath 30 and kept at a constant temperature. From this state, when a constant heat flow rate Q ′ is supplied to the sample S by the heater 11 in the sample container 1, the temperature of the sample S rises and eventually becomes constant as shown in FIG. The vertical axis of FIG. 2 is the temperature difference ΔT between the temperature of the sample S and the temperature of the constant temperature bath, and the temperature ΔT _max that becomes constant with respect to the applied heat flow rate is measured. Energy in the cooling process of Figure 2 is not supplied (Q is' = 0), the heat flow Q _L emitted in a constant temperature bath 30 'is released from the heat flow Q _X' the sample container 1 which is emitted from the sample S Heat flow rate Q _V '. That is, the _{Q L '= Q X' +} Q V '··· (1).

[0026] Here, when calculating the energy balance in the steady state (the temperature difference ΔT becomes constant 2) because is balanced 'heat flow Q _L emitted a' supply heat flow Q, Q is a _{'= Q L' ··· (2} ), heat flow Q _L emitted ', given to be proportional to the temperature difference ΔT between the temperature of the temperature and a thermostat 30 of the sample S, Q _L' = αΔT (3) It should be noted that this equation (3) holds even in a state other than the steady state. Therefore, the heat transfer coefficient α can be obtained by the equation (4).

Α = Q ′ / ΔT _max (4) From the results obtained by measuring several times under the condition that the heat flow rate Q ′ supplied by the heater 11 is changed, the heat transfer coefficient α is expressed by the equation (5).
It is obtained in a relationship like.

Α = βΔT ^r (5) Here, the power r represents a device constant, and as shown in FIG. 3, the above logarithmic graph in which both ΔT _max and α are expressed in logarithm is shown above. The relationship between α and ΔT _max thus obtained is plotted and the slope of the straight line is shown.

By calibrating the heat flow rate Q _V 'released from the sample container 1 with water or the like, the sample S is cooled in the cooling process of FIG.
The heat flow rate Q _X 'which is released from can be calculated by equation (6).

Q _X '= Q _L ' -Q _V '(6) Heat flow Q _X ' of sample S, sample mass M, constant pressure specific heat C _p ,
The relationship of the formula (7) is established between the temperature differences ΔT, and Q _X '= MC _p (−dΔT / dt) (7) According to the formula (7), the sample S is released with the temperature drop. The heat quantity Q _{X to be obtained} is Q _X = ∫Q _X 'dt = −∫MC _p dΔT (8) For example, if it is assumed that the temperature difference during measurement of the constant pressure specific heat C _p is irrelevant to the temperature, numerical integration is performed using the data measured once in about 0.2 seconds (= Δt).
Expression (8) can be approximated by Expression (9).

Q _X ≉ΣQ _X 'Δt = −MC _p ΔT (9) The heat capacity MC _{p of the} sample S can be obtained from the equation (9). For the mass M of the sample S, the internal volume V _C of the sample container 1 is preliminarily tested,
It is calculated from the density ρ of the sample measured by the method described below.

M = ρV _C (10) From these, the constant pressure specific heat C _p of the sample S is calculated.

Here, when the heat flow rate Q _V 'released from the sample container 1 is tested using water or the like, from the equation (1), Q _V ' = Q _L '-Q _X ' ... (11) The cooling rate of the sample (water) becomes a substantially straight line as shown in FIG. 4 when the cooling curve shown in FIG.

ΔT = ae ^bt (12) Therefore, the cooling rate becomes dΔT / dt = bae ^bt = bΔT (13), and when the result of equation (13) is substituted into equation (7), Regarding the sample (water), Q _X '= -MC _p bΔT≡BΔT (14), and by substituting the equations (14) and (3) into the equation (11), Q _V ' = αΔT-BΔT (15) Here, α = βΔT ^r and B = −MC _p b, which are determined at each state point. Note that M and C _p here
Are the mass of the sample (water) and the specific heat of constant pressure, respectively.

In this way, in the cooling process of FIG. 2, the heat flow rate Q _V ′ released from the sample container 1 is obtained by the equation (15). On the other hand, 'since the obtained formula (6) heat flow Q _X emitted from the sample S from the relationship of' heat flow Q _L emitted from the equation (3) in a thermostat 30 Motomari is, the heat flow Q _X ' Is related to the equation (9), the heat capacity MC _{p of the} sample S is
Is required. Then, from the equation (10), the constant pressure specific heat C of the sample S
_p is calculated.

By the way, the mass M of the sample S in the sample container 1
With respect to, the temperature and pressure at the state point to be measured are set by the temperature of the thermostatic bath 30 and the pressure applied to the metal bellows 3, respectively, and after a sufficiently steady state is obtained, the measured value of the displacement of the metal bellows 3 is obtained. By previously using water to test the relationship between the displacement L of the metal bellows 3 and the internal volume V and creating a correlation formula, the measured value L of the displacement of the metal bellows 3 in each measurement is used to calculate the volume V of the sample S. Is calculated. The mass M _all of the filled sample S is measured by a balance in advance, and the density ρ is calculated from the following equation (16).

Ρ = M _all / V (16) By previously determining the internal volume V _C of the sample container 1 using water, the above equation (10) is obtained from the density ρ obtained above. )
Thus, the mass M of the sample S can be obtained.

FIG. 5 is a system configuration diagram of one embodiment in which the constant pressure specific heat measuring device of FIG. 1 is actually configured. FIG. 6 is a perspective view showing the whole of the device, and FIG. 7 is a perspective view showing its main part. The figure is shown. Silicon oil, for example, is used as the oil O of the heat transfer medium in the liquid constant temperature bath 30, and its temperature is detected by using the thermometer 14 composed of a standard platinum resistance thermometer, and the resistance value is detected by the precision AC bridge. Measured at 41, I
Calculated according to TS-90. To control the temperature of the silicon oil O, the amount of heat flowing out to the outside is adjusted to the main heater 61.
Besides, fine adjustment is performed by the sub heater 63. Main heater 6
Adjustment of 1 is roughly controlled manually,
For the fine adjustment, the voltage of the deviation signal from the resistance value at the predetermined temperature set by the precision AC bridge 41 is adjusted by the PID controller 6
4 and outputs the voltage adjusted by the PID controller 64 to the sub-heater 63 for control. For the low temperature range, a cooler 62 is further used. Further, a stirrer 15 is attached to reduce the temperature distribution of the silicone oil. Here, the PID controller (proportional / integral / derivative controller) 64 is a device equipped with a general control method (PID control) for performing constant value control.
-90 is the 1990 international temperature scale, which defines an international temperature standard.

In order to set and control the pressure of the metal bellows 3 to a predetermined value, for example, nitrogen gas is used as the gas G which applies a predetermined pressure from the outside of the metal bellows 3, and nitrogen gas is supplied from the nitrogen cylinder 67. In the high pressure region, the oil type high pressure pump 65 is used to pressurize the nitrogen gas through the oil-nitrogen separator 66, and the pressure of the nitrogen gas G is measured using the dead weight type pressure gauge 42. The dead weight type pressure gauge 42 can measure the pressure and can keep the pressure constant, and the pressure controller 68 is used for the fine adjustment.

Inside the sample container 1, a thermometer 12 made of a platinum resistance thermometer and a heater 11 made of a rod-shaped micro-heater are inserted, and both have a stainless sheath so as to withstand high pressure. The sample S is directly heated by the heater 11, and the temperature change of the sample S at that time is detected by the thermometer 12. The resistance value of this thermometer 12 is
The difference from the resistance value corresponding to the temperature of the constant temperature bath 30 is measured by the precision grade AC bridge 43 and calculated as the temperature change of the sample S due to the heating and cooling processes. Further, the supplied heat flow rate is calculated as Joule heat by using the micro heater 11, the standard resistor 44, and the DC constant voltage source 45, measuring the voltage with the digital multimeter 46. Metal bellows 3
The displacement amount is measured by a displacement meter 48 outside the thermostatic chamber 30 with a sensor for the differential transformer 47 attached to the tip of the rod 53 attached to the metal bellows 3. Differential transformer 4
Since 7 can be measured by a non-contact type, the rod 53 is housed in the pressure pipe communicating with the pressure vessel 4, and the position is detected from the outside of the pressure pipe. Differential transformer 47
Is fixed to the linear movement stage 49, and the linear movement stage 49 moves in parallel with the movement of the rod 53. When the rod 53 moves in conjunction with the movement of the metal bellows 3, the induced electromotive force shown in the digital multimeter 46 is generated according to the displacement amount, and the induced electromotive force is always 0 so that the position reference is determined. , The differential transformer 4 so that the value becomes 0
7 is moved in parallel, and the moving amount of the linear movement stage 49 at that time is attached to the linear movement stage 49.
Is measured and displayed on the counter 51, which is measured as the displacement amount of the metal bellows 3. The outputs of these digital multimeter 46 and precision AC bridge 41 are GPIB,
The data is taken into the personal computer 52 via RS232C (transmission cable standard) and the data is recorded at intervals of approximately 0.2 seconds.

In such a structure, the supply heat flow rate is
It is supplied by the Joule heat of the micro heater 11 inserted in the calorimeter 10. The heat flow rate supply circuit is shown in FIG. If the voltage applied to the micro-heater 11 is V ₁ , the resistance value of the standard resistor 44 is R _2, and the voltage applied to it is V ₂ ,
The Joule heat Q ′ is calculated as Q ′ = V ₁ · V ₂ / R ₂ . A digital multimeter 46 is used to measure the voltage.

The resistance value of the thermometer 12 is determined by the constant temperature bath 30.
The difference with the resistance value corresponding to the temperature is measured by the precision grade AC bridge 43, and is calculated as the temperature change of the sample S due to the heating and cooling processes. Convert the voltage of the deviation signal into a temperature change. If the resistance value setting button of the precision AC bridge 43 is adjusted so that the voltage of the deviation signal from the precision AC bridge 43 at the temperature of the constant temperature bath 30 before the heat flow is supplied becomes 0, the sample after the heat flow is supplied. The temperature change of S is ΔT = k · V _T / 1 using the voltage of the deviation signal and the temperature conversion coefficient.
It can be calculated as 0. However, the temperature conversion coefficient k is a temperature difference (K) per voltage of 10 V of the deviation signal, and needs to be set in advance to a value larger than the maximum temperature difference that will rise.

The constant pressure specific heat measuring method using the apparatus of the embodiment shown in FIGS. 5 to 7 will be omitted because it is clear from the explanation of the principle of calculating the constant pressure specific heat capacity and density.

Using such a device, there have already been 250-4
The one that can be measured in the temperature and pressure range up to 73K and 20MPa is completed.

Although the method and apparatus for measuring the constant pressure specific heat of high-pressure fluid of the present invention have been described above based on the principle and embodiments thereof, the present invention can be modified and developed in various ways. For example,
Instead of the metal bellows 3, a variable container composed of a cylinder and a piston may be used.

[0046]

As described above, according to the method and apparatus for measuring the constant pressure specific heat of high-pressure fluid of the present invention, the sample is hermetically sealed in a container in a batch system, and a complicated structure for performing control inside and outside the sample is provided. With a simple structure of installing a container containing a sample in a thermostatic chamber without having a fixed volume, it is possible to measure the constant pressure specific heat capacity of a high-pressure fluid. It will be possible to do by filling, especially,
Since it is sealed even for samples that are difficult to handle, such as toxicity, it can be measured safely and in a short time, the structure of the device is simple, maintenance is easy, and the cost of manufacturing can be reduced. . Moreover, since it is possible to measure with a small amount of sample, it is suitable for an expensive and valuable sample that has just been developed.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a constant pressure specific heat measuring device for high pressure fluid according to the present invention.

FIG. 2 is a graph showing a temperature rising process, a steady state, and a cooling process when a constant heat flow rate is supplied to the sample.

FIG. 3 is a diagram of a straight line obtained by plotting and connecting a relationship between a heat passage coefficient when a heat flow rate to be supplied is changed and a temperature which is constant with respect to a given heat flow rate.

FIG. 4 is a semilogarithmic graph of the cooling curve shown in FIG.

FIG. 5 is a view showing an actual configuration 1 of the constant pressure specific heat measuring device of the present invention.
It is a system block diagram of an Example.

FIG. 6 is a perspective view showing the entire apparatus of FIG.

7 is a perspective view showing a main part of the apparatus of FIG.

FIG. 8 is a diagram showing a heat flow rate supply circuit.

[Explanation of symbols]

S ... Sample G ... Gas O ... oil 1 ... Sample container 2 ... Piping 3 ... Metal bellows 4 ... Pressure vessel 5 ... Piping 6 ... Volumetric 7 ... Piping 8 ... Valve 10 ... Calorimeter 11 ... Heater 12 ... Thermometer 13 ... Heater 14 ... Thermometer 15 ... Stirrer 20 ... Metal bellows volume meter 30 ... Liquid thermostat 41 ... Precision grade AC bridge 42 ... Weight pressure gauge 43 ... Precision AC bridge 44 ... Standard resistor 45 ... DC constant voltage source 46 ... Digital multimeter 47 ... Differential transformer 48 ... Displacement meter 49 ... Linear stage 50 ... Magnescale 51 ... Counter 52 ... Personal computer 53 ... Rod 61 ... Main heater 62 ... Cooler 63 ... Sub heater 64 ... PID controller 65 ... High-pressure pump 66 ... Oil-nitrogen separator 67 ... Nitrogen cylinder 68 ... Pressure controller

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Claims (6)

[Claims] 1. A sample container having a predetermined volume and a variable container whose volume is variable by pressure from the outside are connected by a pipe, and the sample container and the variable container are installed in a thermostatic chamber so that the variable container is fixed. With pressure applied, a heat flow rate is externally supplied to the sample in the sample container to bring the temperature of the sample to a steady state,
In the cooling process, the heat flow rate released to the constant temperature bath is determined from the temperature difference between the sample and the constant temperature bath and the heat transmission coefficient, while the heat flow rate released from the sample container using a standard sample is determined, From the difference between the heat flow rate released to the constant temperature bath and the heat flow rate released from the sample container, the heat flow rate released from the sample is obtained, and the total heat flow rate released from the obtained sample is calculated. A constant pressure specific heat measuring method for high-pressure fluid, characterized in that the heat capacity of the sample is obtained from the temperature difference between the sample and the constant temperature bath at that time. 2. The volume of the sample under the constant pressure state is obtained from the deformation amount of the variable container, the density of the sample is obtained from the volume, and the specific heat of the sample is obtained based on the obtained density. The constant pressure specific heat measuring method of the high-pressure fluid according to claim 1. 3. The heat transfer coefficient is obtained from the result of changing the heat flow rate supplied to the sample in the sample container from the outside to bring the temperature of the sample into a plurality of steady states. A method for measuring a constant pressure specific heat of a high-pressure fluid as described above. 4. A sample container for containing a fluid sample,
A variable container communicated with the sample container by a pipe and a pressure container accommodating the variable container are arranged in a temperature-controllable thermostatic chamber, and a space between the variable container and the pressure container is provided. Means for setting and controlling the pressure to a predetermined value, means for detecting the amount of deformation of the variable container, heating means for supplying a predetermined amount of thermal energy to the sample in the sample container, and sample in the sample container And a constant temperature is applied to the variable container, the sample in the sample container is supplied with a heat flow rate by the heating means to keep the temperature of the sample constant. State, the heat flow rate released to the constant temperature bath in the cooling process is determined from the temperature difference between the sample and the constant temperature bath and the heat transfer coefficient, while the heat flow rate released from the sample container using a standard sample is determined. Sought, said sought From the difference between the heat flow rate discharged to the warm bath and the heat flow rate discharged from the sample container, the heat flow rate released from the sample is obtained, and the total heat flow rate released from the obtained sample and the sample at that time And a constant pressure specific heat measuring device for high-pressure fluid, characterized in that the heat capacity of the sample is obtained from the temperature difference between the constant temperature bath and the constant temperature bath. 5. The constant pressure specific heat measuring device for high-pressure fluid according to claim 4, wherein the variable container is made of a metal bellows. 6. The constant pressure specific heat measuring device for high pressure fluid according to claim 4, wherein the variable container comprises a cylinder and a piston.