JPS62162960A - Pyrolysis device for analysis - Google Patents

Abstract

PURPOSE:To improve the reproducibility of analytical data and to improve the accuracy of analysis by providing a temp. control means for instantaneously changing the atmospheric temp. of a sample for pyrolysis to be transferred from the low temp. at which the pyrolysis is not caused at all to the set pyrolysis temp. CONSTITUTION:An operator removes an annular cap 15, takes out a sample holder cylinder 16, mounts a sample bar 20 contg. the sample for pyrolysis to be analyzed in a vessel 20a into a sample inserting cylinder 14, and screwing a cap 15 thereto to hermetically seal the cylinder. A carrier gas is then admitted at a prescribed flow rate from upper and lower carrier gas introducing ports 13, 22 into a pyrolysis tube 1. The transfer heat and radiation heat from a heating furnace 3 are diffused to the external air by the effect of radiation fins 21a in a holder part 12 and a non-pyrolysis region Z1 is kept at the low temp. The carrier gas admitted through the introducing port 22 is preheated and the temp. atmosphere in a pyrolysis region Z2 is kept at the set pyrolysis temp. at all times. The pyrolysis is thus instantaneously executed upon falling of the sample bar 20 and the reproducibility of the analytical data is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention mainly applies to the analysis of solid samples under a set temperature in analysis using gas chromatographs, mass spectrometers, gas chromatograph-mass spectrometers, CI-IN analyzers, etc. The present invention relates to an analytical pyrolysis device used to carry out pyrolysis at a temperature of 100 nm and to send the pyrolysis products together with a carrier gas to a column of the above-mentioned analytical instrument.

[Conventional technology]

Generally, this kind of pyrolysis equipment has a part of the sample holder at one end of the pyrolysis tube inserted into the heating furnace, and a carrier gas is passed from this part of the sample holder to the gas outlet at the other end of the pyrolysis tube. The sample for pyrolysis held in a part of the sample holder is transferred to the heating center of the pyrolysis tube, that is, the pyrolysis region, where it is pyrolyzed, and the pyrolysis products are released together with the carrier gas from the gas outlet. It is designed to be sent to a column of analytical equipment. For example, in a gas chromatograph, the type and amount of each component is determined by taking advantage of the fact that the transit time of each component of the decomposition product after thermal decomposition to the column outlet varies depending on the affinity with the column packing. The sample is identified by detection.

Therefore, in this type of pyrolysis device, if the pyrolysis time is delayed, the reliability of the above-mentioned transit time of each component based on the detection time at the column outlet will be lost, so pyrolysis is performed instantaneously. It is hoped that Therefore, as analytical pyrolysis equipment that performs pyrolysis instantaneously in this way, the Curie point method (documents unknown) and the vertical pyrolysis tube method (Japanese Patent Publication No. 5
No. 4-32356, No. 55-5060, etc.) have been proposed.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional Curie point type apparatus has the drawback that the set thermal decomposition temperature cannot be arbitrarily selected, and the thermal decomposition tends to be insufficient due to the small heat capacity, resulting in poor reproducibility. On the other hand, in the vertical pyrolysis tube type device, the pyrolysis sample is dropped from a part of the sample holder to the heating center of the pyrolysis tube by its own weight, and it is different from the above-mentioned Curie point method or the conventional general-purpose horizontal pyrolysis tube. Although the reproducibility is better than that of the method, there are problems in that by-decomposition products are produced and the reproducibility decreases as the amount of carrier gas increases.

[Means for Solving the Problems 1] In view of the above-mentioned circumstances, the inventors have made extensive studies, and as a result, in this type of pyrolysis apparatus, the sample for pyrolysis is placed in a sample holder as shown in FIG. When the sample is transferred from the non-thermal decomposition zone Z Ideally, the temperature should change to T2, but in the conventional vertical pyrolysis tube type apparatus, a part of the sample holder is heated by heat conduction or radiation from the heating furnace, which means that the sample may fall. The dashed line l in the diagram shows how far! , secondary decomposition occurs as the temperature rises, and since the temperature of the carrier gas is low, the larger the amount, the longer it takes to reach the set thermal decomposition temperature after falling, as shown by the broken line 7 to 2 in the figure. It was found that the reproducibility of analysis was reduced, and it was therefore discovered that an excellent analytical pyrolysis device could be achieved by eliminating these detrimental factors.

That is, the present invention provides an analytical pyrolysis apparatus that transfers a pyrolysis sample from a non-pyrolysis region to a pyrolysis region, pyrolyzes it, and sends the pyrolysis product together with a carrier gas to a column of an analytical instrument. The present invention relates to an analytical pyrolysis apparatus characterized by being provided with a temperature control means for instantaneously changing the ambient temperature of a transferred pyrolysis sample from a low temperature at which no pyrolysis occurs to a set pyrolysis temperature.

[Structure and operation of the invention]

The non-pyrolysis area in this invention is an area including a part of the sample holder where the sample for pyrolysis is loaded into the apparatus and temporarily stood by until it is pyrolyzed, and a transfer route to the pyrolysis position.
Moreover, the pyrolysis region means the heating center where the sample is thermally decomposed. The temperature control means provided in the analytical pyrolysis apparatus of the present invention instantly changes the temperature atmosphere of the sample transferred from the non-pyrolysis region to the pyrolysis region from a low temperature at which no pyrolysis occurs to a set pyrolysis temperature. There are specific configurations for each plate, but usually a combination of a cooling device in the non-thermal decomposition region and a preheating device for the carrier gas introduced just before the thermal decomposition region is preferably employed.

In other words, in the non-thermal decomposition region, by preventing temperature rise due to heat conduction or heat radiation from the pyrolysis region using the cooling device, the temperature atmosphere of the sample is maintained at a low temperature at which no thermal decomposition occurs. By injecting a preheated carrier gas just before the thermal decomposition zone, the time delay in reaching the set thermal decomposition temperature caused by the low temperature of the carrier gas in the conventional method is eliminated, and the above-mentioned instantaneous temperature It makes change possible.

Various structures can be adopted as the device configuration of the analytical pyrolysis apparatus of this invention, but it is possible to form a part of the sample holder at one end of the pyrolysis tube whose heating center is surrounded by a heating furnace. A common structure is that a gas outlet connected to the column of the analytical instrument is provided at the other end, and carrier gas inlets are provided at two locations, one at a portion of the sample holder and one immediately before the heating furnace. The above-mentioned pyrolysis tube may be vertical, inclined, or horizontal, but in the case of a horizontal type, it is necessary to use a rod-shaped operating tool to transfer the sample from a part of the sample holder to the heating center. However, in the case of vertical and inclined types, the transfer can be carried out by falling under its own weight, which has the advantage that the transfer time is constant and fast. is large.

Here, the head device in the non-pyrolysis region, which is one of the temperature control means, includes radiation fins, air cooling devices, water cooling devices, and combinations thereof. It is best to attach it to key points or the entire area on the sample holder side.

Furthermore, the preheating device for the carrier gas that flows in just before the pyrolysis region is designed to raise the temperature of the carrier gas that flows into the pyrolysis tube from the fathom hole located just before the heating furnace out of the two carrier gas inlets mentioned above. The preheating temperature is preferably about -15°C to +15°C with respect to the set heat freshness. Note that it is important that the carrier gas flowing in from the gas inlet on the sample holder side is not preheated, as in the conventional case. The carrier gas introduction ratio of both inlets is preferably about % to % for non-preheated portion/preheated portion. Samples for pyrolysis are gas chromatographs, mass spectrometers, and gas chromatographs/mass spectrometers. , a CHN analyzer, etc., as long as it can be thermally decomposed into an analytical gas, and may be a liquid, but generally a solid is used. The sample is then held in a part of the sample holder in a suitable container and transported to the pyrolysis region.

FIG. 1 is a longitudinal sectional view showing an example of the structure of a vertical thermal dividing tube type analytical pyrolysis apparatus to which the present invention is applied.

In the figure, 1 is an upper cylinder 1a and a lower cylinder 1b formed of quartz tubes.
It is a vertical pyrolysis tube connected with a pipe joint 2, and a lower tube 1b is arranged to penetrate through the heating furnace 3. This heating furnace 3
is an electric heater 4 that surrounds the lower cylinder 1b therein.
and a heat insulating layer 5 made of firebrick covering its outer periphery, and the entire body is housed in a casing 6. Further, a slit plate 7 is inserted into an intermediate position within the lower cylinder 1b, that is, a heating center portion constituting the thermal decomposition zone Z2, and glass wool 8 is filled below the slit plate 7. 9 is a gas outlet member connected to the lower end of the lower cylinder 1b.

A plurality of columns 1 are installed on the upper surface of the casing 6.
A sample holder part 12 is mounted on a mounting plate 11 supported via a
is provided. This sample holder part 12 is composed of a sample insertion cylinder 14 equipped with an upper carrier gas inlet 13 on the side, and a sample holder cylinder 16 connected to the upper part thereof via an annular cap 15. The upper end of the upper tube 1a of the pyrolysis tube 1 is connected via a pipe joint 17 to the lower end of the sample insertion tube 14 that passes through the tube. Note that the non-thermal decomposition region Z1 is constituted by the inside of the sample insertion tube 14 and the upper tube 1a. Further, the sample holder tube 16 is loaded with an operating tool 19 that is urged upwardly by a coil spring 18.
The sample rod 20 is held at the upper end of the lower end claw portion 19a of the operating tool 19, which has a tapered outer peripheral surface that widens toward the end.

The sample for pyrolysis is housed in a dish-shaped container 20a provided at the lower end of the sample rod 20.

Further, a jacket tube 21 having a plurality of radiation fins 21a is fitted to the upper end of the upper cylinder 1a of the pyrolysis tube 1 and the upper end of each support 10, and the pyrolysis tube 1 and each support 10 It is configured to dissipate heat conducted from the heating furnace 3 side to the holder part 12 side through the heating furnace 3 side and radiant heat from the heating furnace 3 side to the outside air.

On the other hand, the pipe joint 2 is provided with a lower carrier gas introduction port 22 on the side, and a coiled carrier gas introduction pipe 23 is connected to this introduction port 22.

A carrier gas preheating device 26 consisting of an electric heater 24 surrounding the carrier gas introduction pipe 23 and a refractory brick 25 covering the outer periphery of the carrier gas preheating device 26 is housed in a casing 26a that also integrally covers the pipe fitting 2 portion. It is installed on the casing 6 of 3.

Note that the connection parts between the upper tube 1a and the lower tube 1b of the pyrolysis tube 1, the lower tube 1b and the gas outlet member, the upper tube 1a and the sample insertion tube 14, and the sample insertion tube 14 and the sample holder tube 16 are made of packing. It is sealed at 27.

In order to pyrolyze a pyrolysis sample using the analytical pyrolysis apparatus configured as described above, the annular cap 15 is removed, the sample holder cylinder 16 is taken out, and the sample rod 20 containing the pyrolysis sample to be analyzed is placed in the container 20a. The lower end claw part 19 of the operating tool 19
a, load it into the sample insertion tube 14, attach the annular cap 15 to seal the inside, and then introduce the carrier gas into the pyrolysis tube 1 through the upper and lower carrier gas inlets 13.22. Let it flow at a predetermined flow rate. At this time, in the holder part 12, conductive heat and radiant heat from the heating furnace 3 are dissipated to the outside air by the action of the radiation fins 21a, so the temperature atmosphere in the non-thermal decomposition region Z1 is such that the sample does not undergo thermal decomposition at all. It is kept at a low temperature that does not occur. Next, operation tool 1
9 is pushed in, the lower end claw portion 19a separates from the tapered hole 16a of the sample holder tube 16 and opens with its own elastic force, and the sample rod 20 falls down inside the pyrolysis tube 1 due to its own weight and passes through the slit plate. A dish-shaped container 20a is located above 7, that is, in the pyrolysis zone Z2, and the sample for pyrolysis contained therein is pyrolyzed, and the pyrolysis products are passed through the slit plate 7 and the glass wool 8 together with the carrier gas to the gas outlet member 9 It is then sent to a column (not shown) of an analytical instrument connected to this.

Here, the above thermal decomposition is performed because the carrier gas flowing in from the lower carrier gas inlet 22 is preheated and the temperature atmosphere in the thermal decomposition zone Z2 is always maintained at the set thermal decomposition temperature. This happens instantaneously at the same time as the drop. Therefore, the time taken for each component of the thermal decomposition product to pass through the column of the analytical instrument can be detected with good reproducibility based on the falling time of the sample rod.

Figure 3 shows 1.2-
This is a gas chromatogram obtained by analyzing the thermal decomposition product of polybutadiene 0.1 cm at 500°C using a gas chromatograph. Peak a in the figure is methane,
b represents ethane, C represents ethylene, d represents propane, e represents propylene, and ``respectively represents a decomposition product component of 1.2-polybutadiene.

On the other hand, in FIG. 4, all of the sleeve tube 21 having cooling fins 21a in the configuration shown in FIG. This is a gas chromatogram obtained when a similar analysis was performed by introducing the carrier gas through the port 13, and each peak a-
It can be seen that the appearance time of f is shifted and the reproducibility deteriorates, and furthermore, secondary decomposition occurs due to temperature rise in a part of the sample holder, and a peak g of secondary decomposition products appears.

In addition, in the thermal analysis pancreatic device according to the present invention, the design can be changed in various ways such that the pyrolysis tube is inclined or horizontal in addition to the above-mentioned structure, or the detailed structure is different from the above-mentioned structure example. Furthermore, it goes without saying that an air cooling or water cooling device may be used as a cooling device in the non-thermal decomposition region in addition to the radiation fins 21a. Further, residual heat from the heating furnace 3 or an analytical instrument such as a gas chromatograph may be used as the heat source of the carrier gas preheating device.

[Effect of the invention 1 The analytical pyrolysis apparatus according to the present invention changes the temperature atmosphere of the pyrolysis sample transferred from the non-pyrolysis region to the pyrolysis region from a low temperature at which no pyrolysis occurs to a set pyrolysis temperature. Since it is equipped with a temperature control means that changes the temperature instantaneously, no side decomposition occurs in the sample at a temperature lower than the set pyrolysis temperature, and pyrolysis occurs instantaneously even if the amount of carrier gas is large. Therefore, the reproducibility of analytical data is extremely good, and analytical accuracy and reliability can be greatly improved compared to conventional devices of this type.

Examples] Examples of the present invention will be specifically described below in comparison with comparative examples.

Example Using an analytical thermal decomposition apparatus having the apparatus configuration shown in FIG. Connect to the upper carrier gas inlet 13 and use nitrogen gas as the carrier gas.
The temperature of the carrier gas introduced from the lower carrier gas inlet 22 is set to 23°C, and the flow rate ratio of both carrier gases is set to 23°C.
The lower part = 115, and at a set pyrolysis temperature of 500'C, commercially available 1,2-polybutadiene was used as a pyrolysis sample, and the total amount of carrier gas was 40 me1 min at the two usage amounts listed in Tables 1 and 2 below. ,60me1
A total of six analyzes of thermal decomposition products were carried out under three conditions: 80 m ('/min) and 80 m ('/min). The gas chromatograph measurement conditions were as follows:
~100 mesh) was packed into a copper column tube with a length of 2 m and an inner diameter of 3 mm, and the column temperature was kept at a constant temperature of 30°C.

Comparative Example 1 A sleeve 2 having heat dissipation fins 21a based on the device configuration of the example
The analysis was conducted in the same manner as in the example except that 1 was completely removed.

Comparative Example 2 The carrier gas preheating device 26 in the device configuration of the example was stopped and all the carrier gas was transferred to the upper carrier gas inlet 13.
Analysis was conducted in the same manner as in the example except that the introduction was performed at 23°C.

Comparative Example 3 A sleeve 2 having heat radiation fins 21a based on the device configuration of the example
1, and remove the carrier gas preheating device 26.
to the upper carrier gas inlet port 1.
The analysis was conducted in the same manner as in Example except that the temperature was introduced at 23°C.

Comparative Example 4 Analysis was carried out in the same manner as in the example except that a Curie point type pyrolysis device (trade name JHP-35, manufactured by Japan Analytical Industry Co., Ltd.) was used as the pyrolysis device for analysis.

The reproducibility of analytical data was evaluated for the gas chromatograms obtained in the above Examples and Comparative Examples, and the results are shown in Tables 1 and 2. Note that m in the table is 1 of the area ratio b/f of the peaks corresponding to peak b and peak f in Figure 3.
The average value of 0 times, σ indicates the standard deviation. Further, among these gas chromatograms, a sub-decomposition peak corresponding to peak g in FIG. 4 appeared in Comparative Example 1 and Comparative Example 3.

As is clear from the upper table of Table 1 and Table 2, the analytical pyrolysis apparatus according to the present invention has extremely good reproducibility of analytical data regardless of increases or decreases in the amount of carrier gas and the amount of sample for pyrolysis. be. On the other hand, in similar devices without temperature control means (Comparative Examples 1 to 3), the reproducibility decreases as the amount of carrier gas and the amount of sample for pyrolysis increases, especially when there is no preheating device for the carrier gas ( It can be seen that this tendency is remarkable in Comparative Examples 2 and 3). Furthermore, since the conventional Curie point type device (Comparative Example 4) has a small heat capacity,
It can be seen that the reproducibility is significantly poor. On the other hand, when there is no cooling device in the non-thermal decomposition region (Comparative Examples 1 and 3), secondary decomposition occurs as described above.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of the structure of the analytical pyrolysis apparatus according to the present invention, and FIG. 2 is the relationship between temperature calculation, surrounding air, and time during the transfer of a pyrolysis sample from a non-thermal decomposition area to a pyrolysis area. FIG. 3 is a diagram showing an example of a gas chromatogram using the device of the present invention, and FIG. 4 is a diagram showing an example of a gas chromatogram using the conventional device. Zl...non-thermal decomposition area, Z2/thermal decomposition area, T1...
- Low temperature that does not cause any thermal decomposition, T2... Setting thermal decomposition temperature, 21a... Cooling fins (cooling device), 26... Carrier gas preheating device patent applicant Hitachi Maxell, Ltd. z1. #￥Heat☆Solution/fi value

Claims (2)

[Claims] (1) In an analytical pyrolysis device in which a sample for pyrolysis is transferred from a non-pyrolysis region to a pyrolysis region to be pyrolyzed and the pyrolysis products are sent to a column of an analytical instrument along with a carrier gas, the transferred heat is A pyrolysis device for analysis, characterized in that it is provided with a temperature control means for instantly changing the ambient temperature of a sample for decomposition from a low temperature at which no pyrolysis occurs to a set pyrolysis temperature. (2) The analytical pyrolysis apparatus according to claim 1, wherein the temperature control means comprises a cooling device in the non-pyrolysis region and a preheating device for carrier gas introduced immediately before the pyrolysis region.