JP5186134B2 - Method for producing flame retardant carbide - Google Patents

Description

  The present invention relates to a method for producing a flame retardant carbide which is a stable substance so that the carbide having self-heating property can be safely transported and stored.

  It is considered to use organic waste such as feces and urine discharged from a barn as carbide. However, the produced carbide has a problem that it itself burns out during storage. This is considered that the carbide has a self-heating property, and the temperature rises due to the self-heating during storage, and the ignition occurs when the temperature exceeds a certain temperature. Therefore, it was necessary to suppress combustion due to this ignition in handling the carbide.

In this regard, JP 2004-267950 A shows that it is effective to oxidize carbide in a low-temperature oxidizing atmosphere. The grounds for this are believed to be as follows. That is, a carbide having a low degree of carbonization contains many active groups having a high activity with respect to an oxidation reaction, and self-heats even at a low temperature of 200 ° C. or lower. However, the self-heating of carbide is a reaction different from the combustion reaction, and is considered to be due to the air oxidation reaction of the active group. At low temperatures, the reaction gradually converges and the active sites (active groups) gradually become active. Disappears and eventually stabilizes. Therefore, if the oxidation reaction is completed at a low temperature in advance, it is possible to suppress the self-heating of the carbide during subsequent storage and prevent combustion due to ignition.
JP 2004-267950 A

  By the way, there is a self-heating substance test based on the UN Recommendation on the Transport of Dangerous Goods regarding the handling of carbides. Specifically, a basket test using a thermostatic bath is performed as shown in FIG. A powdered carbide is put into a mesh basket 101 made of stainless steel having a cube shape of 100 mm square, and the sample 102 is heated in a thermostatic chamber 103 maintained at 140 ° C. The temperature of the sample 102 is measured by the thermocouple 105, and the data logger 106 calculates the temperature from the thermocouple 105 and displays it.

  In this basket test, when the carbide is heated to 40 ° C. or more, it is determined that the substance has a self-heating property. On the other hand, if combustion does not occur even when heated at 140 ° C., even if heating is continued as it is, after the temperature is raised to a certain value, the temperature decreases without generating heat, and the temperature of the atmosphere in the tank reaches 140 ° C. Asymptotics have been obtained as a test result. Therefore, it has been confirmed from this basket test that by heating at a certain temperature, the self-heating carbide is stable and can be safely transported and stored. That is, it can be understood that it is effective to complete the oxidation reaction at a low temperature in advance, but it was not clear how to heat it.

  Then, this invention aims at providing the manufacturing method of the flame retardant carbide | carbonized_material which makes a carbide | carbonized_material a stable substance in order to solve this subject.

The method for producing a flame retardant carbide according to the present invention is to suppress ignition by oxidizing a carbide obtained from an organic waste, and the carbide is placed in a thermostat at 5 mm to 10 mm . the thin layer having a thickness of laying it, you characterized in that the said carbides to heat 10 to 15 minutes at 200 ° C. to 230 ° C. is a temperature below the ignition limit corresponding to the layer thickness.

  Therefore, according to the present invention, for example, even when the temperature of the atmosphere in the tank is set to 200 ° C. or more, for example, by making the carbide a thin layer having a thickness of 10 mm or less, combustion can be performed without causing ignition. The generation of suppressed carbide can be performed in a short time of about 15 minutes.

Next, one embodiment of the method for producing a flame-retardant carbide according to the present invention will be described below with reference to the drawings.
Carbide is produced by drying stored manure discharged from a poultry house or the like and then carbonizing them in a carbonization furnace. The carbide thus obtained can be stored for a long period of time, and can be used as a snow melting agent and a soil conditioner in addition to fertilizer.

  However, if the bag is packed and stored as it is, the carbides have self-heating as described above, and therefore there is a possibility that the temperature naturally rises and ignites. FIG. 1 is a diagram showing a temperature change when the carbide is heated by the method based on the UN recommendation shown in FIG. 8 described above. Specifically, it is a case where 100 mm square carbide is heated at 140 ° C., and shows the temperature change of the central portion and surface of the sample 102 and the atmosphere in the tank.

  As can be seen from the figure, when the temperature of the atmosphere in the tank is raised to 140 ° C., the sample 102 which was about 20 ° C. at the beginning is heated, the surface gradually rises first, and then the temperature rises also in the central portion. It was. Then, the temperature of the sample 102 suddenly rises after about 3 hours from the start of heating, generates heat exceeding 140 ° C. which is the temperature of the atmosphere in the tank, and the internal temperature and surface temperature of the sample 102 continue to rise. Ignited and burned.

On the other hand, FIG. 2 is a view showing a change in temperature when the test is performed by reducing the heating temperature to 120 ° C., which is a method based on the UN recommendation shown in FIG. The temperature measurement points are the central portion and surface of the sample 102 in which carbide is made into a 100 mm square, and the atmosphere in the tank. In such a 120 ° C. heating test, as can be seen from the figure, when the temperature of the atmosphere in the tank is increased to 120 ° C., the temperature of the sample 102, which was about 20 ° C. at the beginning, rises to the surface, and subsequently the central portion. The temperature rose.

  Then, from the time when the heating time reached 4 hours, the internal temperature of the sample 102 started to generate heat exceeding 120 ° C. which is the temperature in the tank. However, although the temperature of the sample 102 was raised to about 130 ° C., after that, the temperature was gradually lowered and gradually approached the temperature of the atmosphere in the tank. Thereby, it can be seen that the heat generation of the sample 102 has subsided. Therefore, the sample 102 was further subjected to a heating test at 140 ° C. FIG. 3 is a diagram showing a temperature change in that case.

  Once the sample 102 that experienced a temperature rise due to heat generation was heated again at a combustible temperature of 140 ° C., it did not burn as shown in FIG. That is, since the sample 102 was heated by itself and the temperature was high, the temperature was initially lowered due to the low-temperature atmosphere in the tank. Thereafter, the sample was heated by the rise in the bath temperature, and the temperature of the lowered sample 102 was also raised to generate heat. However, although the sample 102 generated heat exceeding the temperature in the bath, it only stabilized slightly over a long time as shown in the figure, and finally stabilized at a constant temperature.

  From the above, it can be seen that carbide with reduced self-heating can be generated by low-temperature oxidation treatment in which heat is raised by heat generation in a low-temperature tank. However, in order to raise the temperature of the carbide by generating heat, as can be seen from FIGS. 1 and 2, the treatment time becomes longer when the treatment is performed at a low temperature. On the other hand, if high temperature treatment is performed, the carbides may ignite and burn. Therefore, the inventor of the present application paid attention to the thickness of the carbide, and tested it by changing the treatment thickness and the temperature of the atmosphere in the tank where the carbide ignites and burns. That is, the treatment thickness of the carbide that does not lead to combustion when oxidizing at a high temperature was examined.

FIG. 4 is a diagram showing test results when the carbide is thinned and heated at 200 ° C. A sample in which a powdered carbide was laid thinly in a stainless steel container was placed in a constant temperature bath and heated. For example, in the test whose results are shown in FIG. 4 , two samples having a carbide treatment thickness of 10 mm and 15 mm were prepared, and the atmosphere in the tank was heated to 200 ° C. for both samples.

  Then, although the sample of the 10 mm layer generated heat exceeding the temperature in the tank in about 0.5 hours, the temperature rose to 250 ° C. but then decreased. Therefore, in the case of the 10 mm layer sample, heat was generated by heating at 200 ° C., but it did not ignite and burn. On the other hand, in the case of the 15 mm layer sample, the temperature exceeded the temperature in the tank in about 0.6 hours, and the temperature gradually increased thereafter. And even after finishing the heating, the temperature of the sample itself rose, and eventually ignited and burned.

Therefore, it was found that there are cases where combustion occurs depending on the thickness of the carbide even at the same heating temperature, and combustion may not occur. And the heating test was done by the method based on the UN recommendation shown in FIG. 8 about the sample of the 10 mm layer which did not burn. And FIG. 5 is a figure which showed the temperature change in that case.
Therefore, the carbide after the oxidation treatment described above is placed in a 100 mm square stainless steel mesh basket, and the sample is heated in an atmosphere in a bath at 140 ° C. However, once the sample experienced a temperature rise due to heat generation, even if it was heated again at a combustible temperature of 140 ° C., it only generated a little heat as shown in the figure, and stabilized so as to almost overlap with the temperature in the tank. . Therefore, the carbide | carbonized_material which suppressed combustion by the oxidation process mentioned above was produced | generated.

  In this way, the test was further conducted in various patterns, and the relationship between the treatment thickness of the carbide and the temperature of the atmosphere in the tank was investigated. In the test, heat treatment was performed while changing the treatment thickness, treatment temperature, and treatment time of the carbide, and the treatment time until the product was not combusted in the UN-recommended 140 ° C. basket test was examined. As a result, as shown in FIG. 6, when the processing thickness was 100 mm, a heating time of about 120 minutes at a temperature of 120 ° C. was required. When the treatment thickness was 10 mm, a heating time of about 15 minutes at a temperature of 200 ° C. was required. Furthermore, when the treatment thickness was 5 mm, a heating time of about 10 minutes at a temperature of 230 ° C. was required.

Incidentally, the processing thickness of the test, since the carbide is a thickness that does not reach the combustion, running heat treatment at less than the ignition limit thickness. And, due to the reproducibility of the ignition limit test, whether or not it results in combustion also varies depending on some local thickness change of the sample. For example, in the case of heat treatment at 200 ° C., it does not burn when the treatment thickness is 10 mm, but reliably burns at 15 mm. Therefore, it can be seen that the ignition limit at 200 ° C. is between 10 mm and 15 mm. Therefore, when the oxidation treatment without fire at 200 ° C., it is necessary to make the carbide in a layer thickness of less than 10 mm. At other temperatures, for example, as shown in FIG. 7, it was 50 mm at 150 ° C. and 100 mm at 120 ° C.

  Therefore, when the carbide is oxidized at 120 ° C. with a treatment thickness of 100 mm, it takes 120 minutes to make the carbide stable without igniting, but if the treatment thickness is 10 mm or 5 mm, When heated at 200 ° C. to 230 ° C., it was found that the stabilization treatment can be performed in a time of about 10 minutes to 15 minutes. Therefore, even when the temperature of the atmosphere in the tank is set to 200 ° C. or higher, for example, by forming the carbide in a thin layer with a predetermined thickness, the generation of the carbide with reduced combustion is performed in a short time without causing ignition. It became possible.

As mentioned above, although the manufacturing method of the flame-retardant carbide was demonstrated, this invention is not restrict | limited to the said content.
For example, the relationship between the temperature and the treatment thickness shown in FIG. 7 is an example, and is not limited to this relationship because it varies depending on the properties of the target carbide.

It is the figure which showed the temperature change at the time of heating a carbide | carbonized_material by the method based on a UN recommendation. It is the method based on a UN recommendation, Comprising: It is the figure which showed the temperature change at the time of testing by heating-down to 120 degreeC. It is the figure which showed the temperature change at the time of performing the heating test at 140 degreeC further about the carbide | carbonized_material which heat-processed at 120 degreeC. It is the figure which showed the test result at the time of heating at 200 degreeC by making a carbide | carbonized_material into a thin layer. It is the figure which showed the temperature change at the time of performing the heating test at 140 degreeC further about the carbide | carbonized_material which heat-processed at 200 degreeC as a thin layer. It is the figure which showed the test result of the relationship between process time, process thickness, and process temperature. It is the figure which showed the process thickness which considered process temperature and the ignition limit. It is the figure which showed the basket test of the UN recommendation about dangerous goods transportation.

Explanation of symbols

101 Mesh basket 102 Sample 103 Constant temperature bath 105 Thermocouple 106 Data logger

Claims (1)

In the method for producing flame retardant carbide by suppressing ignition by oxidizing the carbide obtained from organic waste,
The carbide is laid as a thin layer having a thickness of 5 mm to 10 mm in a thermostatic bath, and the carbide is heated at 200 ° C. to 230 ° C. , which is a temperature below the ignition limit corresponding to the layer thickness, for 10 to 15 minutes . A method for producing a flame-retardant carbide characterized in that

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