JPH0116028Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a device for measuring the filling properties of coal-based or petroleum-based tar pits (hereinafter referred to simply as pitches), and more specifically, the filling properties of pitches that are impregnated and filled into carbonaceous calcined or graphite bodies. The present invention relates to a device for measuring the quality of a product.

Recently, in order to manufacture artificial graphite electrodes that can withstand the high-load operation conditions of arc steelmaking furnaces, a method has been developed that usually involves infiltrating a carbonaceous fired body with pitch and then graphitizing it to improve the quality of the resulting electrode. However, in rare cases, it may be filled after graphitization. Hereinafter, the fired body will be described as a representative example.

It is said that the pitch filled in the carbonaceous fired body (electrode) must roughly satisfy the following two conditions.

(1) The pitch must be such that it can be filled evenly to the center of the fired electrode.

(2) The pitch should be one in which more carbonized products remain in the electrode even after filling and firing again.

The condition for item (2) can be easily determined by comparing the fixed carbon content in the industrial analysis values, but the condition for item (1) can be easily determined by comparing the fixed carbon content in the industrial analysis values. The actual situation is that the evaluation method of comparing the size of the quinoline insoluble component (α resin) and benzole insoluble component (β resin) cannot make an accurate comparison, and it is difficult to evaluate and select commercially available filling pitches.

This invention was devised in view of the above-mentioned circumstances with the purpose of providing an apparatus that can directly and easily measure the filling properties of pitches.

Hereinafter, the structure, operation, and effects of the device of this invention will be described in detail with reference to the attached drawings showing the device of this invention.

FIG. 1 is a schematic cross-sectional view showing the configuration of the device, in which 1 is a cylindrical housing with a stepped portion, and a cylindrical packing 2 made of heat-resistant rubber or the like is fitted into the stepped portion of the housing. The standard sample 3 is held by this packing. An outflow pitch receiving funnel 4 is provided below the sample, and an outflow pitch receiver 5 is provided directly below this funnel so as to be interlocked with a measuring device 6. A lid body 7 is placed over the top of the housing 1, and a melting pitch supply pipe 8 equipped with a valve V ₁ and a pressurized gas supply pipe 9 such as air or inert gas equipped with a valve V ₂ are installed on this lid body. provided. A purge pipe 9' equipped with a valve _V3 is attached to this supply pipe 9.
Further, a thermocouple TC ₁ and a pressure gauge P are respectively attached to the lid. Electric heaters 10a and 10b are provided in a ring shape on the upper and lower sides of the outer wall of the casing 1, and a thermocouple _TC2 is provided on the outer side of the stepped portion of the casing.

The operation of each of the above components will be described.

Standard sample 3 is a sample cut out from the fired body, which has been previously tested for apparent specific gravity, air permeability, appearance, etc., and has almost the same characteristics. Here, the air permeability indicates the ease with which gas (for example, air) passes through the sample. Measurement measures the air passing velocity (dv/dt) within a certain difference,
The air permeability k is determined by the following formula.

k=sample thickness x dv/dt/cross-sectional area x differential pressure 100 The rubber packing 2 is suitably made of silicone rubber to prevent the pitch from flowing out along the sides of the sample.

The measuring device 6 is only for measuring the weight of the outflow pitch, and in the case shown in the figure, an example of an automatic measuring device is shown which is composed of a spring 6a and a differential transformer 6b. Rc in the figure indicates a recorder. Alternatively, it may be weighed over time using a platform scale.

Electric heaters 10a and 10b are used to maintain the pitch at a predetermined temperature, and thermocouple _TC2 controls the output of each heater to maintain the indicated value of thermocouple _TC1 at the target temperature.

The pitch supply pipe 8 is a pipe that supplies pitch, which has been melted at a target temperature in advance, into the apparatus.
A predetermined amount of the pitch is admitted into the device by means of valve _V1 . After putting a predetermined amount of pitch into the device,
For example, the valve of the supply pipe 9 supplies inert gas at a predetermined pressure.
Open V ₂ and feed into the device.

The method for measuring the filling property of pitches using this device is to first use a standard sample (for example, 50mmφ x 30mmt).
Attach it to the step inside the housing by inserting it into a rubber packing, and raise the temperature of the sample to the target temperature (for example, 210°C). Next, a predetermined amount (for example, 100 g) is added outside the device.
of the melted pitch 11 is melted at the same temperature as the heated sample, and when the temperature becomes stable, the entire amount of the melted pitch 11 is injected into the apparatus through the valve V ₁ of the supply pipe, and the valve is closed.
Close _V1 and pressurize inert gas ( _N2 gas _:
A pressure of, for example, 5 kg/cm ² ) is applied, and at the same time as the pressure is applied, the weight of the pitch flowing out from the standard sample over time is measured.

Using the device of this invention, three types of pitches with different contents of quinoline insoluble components were prepared: Pitch A with quinoline insoluble components of 0.2 to 0.3%, Pitch B with 2 to 3%, and Pitch C with 10 to 12%. 210℃, pressurized
N ₂ : The results measured at 5Kg/cm ² were graphed and the second
Shown in the figure.

From the measurement results shown in FIG. 2, the pitch that contains a larger amount of quinoline insoluble components has a longer time until the pitch starts dripping from the standard sample and a lower flow rate (dw/dt) thereafter. In other words, it is not suitable as a filling pitch. Further, the measurement results for each pitch are expressed by the general formula t=a+bw+ ^cw2 . As seen in Figure 1, this phenomenon is caused by a sludge 12 containing mainly quinoline insoluble components on the upper surface of the standard sample.
It is thought that this is to control the outflow of pitch. Furthermore, find the appropriate value of the outflow pitch amount on the vertical axis in Figure 2 and the intersection of the measurement line for each pitch, read the time required for a certain amount of pitch to flow out from the horizontal axis, and determine the filling property of the pitch by its size. can be quantitatively evaluated.

Next, embodiments will be described.

[1] Actual measurement example when updating the pitch When I continued filling work on a long-time firing electrode (20-24 inches φ x 72-96 inches cm) using the pitch C mentioned above, the diagonal lines in Figure 3 were observed. The electrode A is shown so that the unfilled part B shown by hatching can be seen.
It turned out that the pitch was not filled to the center. Therefore, using the measuring device of this invention, we measured the time it took to reach a weight of 50g.
190±10 minutes were obtained. (When fresh, ×95±5
Therefore, when the entire pitch that had deteriorated over a long period of time was replaced with a new pitch C, the filling condition was good and there was no unfilled portion. The amount of quinoline insoluble in both pitches at this time is the degraded pitch.
It was 11%, and 10% at the update pitch. Due to the long-term thermal history, it was found that the filling property deteriorated even though the quinoline insoluble content increased slightly, indicating that the filling property cannot be evaluated unconditionally based on the amount of quinoline insoluble content.

[] Actual measurement example when changing the type of Pitch C When filling the above firing electrode with Pitch C, pressure was applied at 7 kg/cm ² for 140 minutes, but when Pitch C was used, pressure was applied for 40 minutes at the same pressure. When pressed, it was found that the fired electrodes were filled to the center.

According to the device of this invention, it is possible to know the filling properties of pitches in advance, predict pitch deterioration, and set appropriate filling conditions.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of the device of the present invention, Fig. 2 is a chart showing the relationship between the outflow pitch amount w (g) and the elapsed time t (min) using the device of the present invention, and Fig. 3 is a graph showing the firing electrode. FIG. 2 is an explanatory diagram showing the state of the unfilled portion of the pitch. Explanation of symbols, 1...Housing, 2...Heat-resistant packing, 3...Standard sample, 4...Outflow pitch receiving funnel, 5...Outflow pitch receiver, 6...Measuring device, 7...Lid body , 8... Test pitch supply pipe, 9...
... Pressurized gas supply pipe, 10a, 10b ... Heater, TC ... Thermocouple, 11 ... Melting pitch, 12
...Suratsuji.

Claims (1)

[Scope of utility model registration request] A standard sample of carbonaceous calcined or graphite material is installed via heat-resistant packing in a case equipped with an electric heater that can control the temperature on the outside, and a pitch receiving funnel is placed below the standard sample, and a measuring device is placed directly below the funnel. A tar pit is provided with an outflow pitch receiver interlocked with the sample, a melting pitch supply pipe and a gas pressure feeding pipe at a predetermined pressure are provided on the lid at the top of the casing, and the outflow amount of the pitch supplied onto the sample is measured. Fillability measuring device.