JP2006271431A - Temperature control method for dehalogenation treatment reaction, and reactor used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely and speedily control the temperature inside of a tank suitable for dehalogenation treatment reaction large in fluctuation of generated heat in particular. <P>SOLUTION: A reaction tank 1 has a jacket 10, and oil to be treated containing organic halogen compound is dripped into an alkali metal dispersing element stored in the tank to react, so that the organic halogen compound is decomposed and treated in this dehalogenation treatment reaction. The temperature in the tank is kept to be a prescribed temperature by a heating medium or a cooling/heating medium which is put into or out from the jacket 10 in this method for controlling temperature. The method comprises: a first heating process which makes the heating medium pass through the inside of the jacket 10 to heat the temperature inside of the tank to a first reference temperature set in advance; a first dripping process which pulls out the heating medium inside of the jacket after reaching the first reference temperature and primarily drips a part of the oil to be treated; and a second dripping process which secondarily drips the oil to be treated while nearly keeping a second reference temperature by making the cooling/heating medium pass through the inside of the jacket from a stage where the temperature in the tank reaches the second reference temperature set in advance after carrying out the first dripping. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a temperature control method in a dehalogenation treatment reaction that has a particularly large change in calorific value, and a reactor suitable for it.

  A method (hereinafter referred to as SD method) is known in which an organic halogen compound such as polychlorinated biphenyl (PCB) is reacted with an alkali metal dispersion such as sodium metal to decompose the organic halogen compound. In this SD method, it is important to react the liquid in the tank within a predetermined temperature range, but it is a highly exothermic reaction and it is not easy to control the reaction temperature. This is especially true when the oil to be treated is treated with a high concentration of PCB (having a content of 1% or more) and the reaction temperature is 140 ° C. or higher in order to increase the reaction rate. In order to prevent the deterioration of the oil, it is necessary to maintain the temperature range below 200 ° C. In high concentration treatment, the temperature control is usually difficult because the calorific value changes abruptly in the vicinity of the initial stage of the reaction.

  As the above temperature control method, a temperature control method is widely adopted in which the reaction tank has a jacket and the temperature in the tank is maintained at a predetermined temperature by a heat medium or a cooling medium passed through the jacket. However, in the conventional configuration, even if the cooling medium is immediately supplied to the rapid temperature rise in the exothermic reaction to start cooling, or the heating medium is supplied to the sudden temperature drop to start heating, Supply and discharge of cooling / heating medium and heating medium to / from the jacket, time delay of heat transfer from the cooling / heating medium and heating medium in the jacket to the liquid in the tank, that is, a time lag occurs, and the temperature of the liquid in the tank is controlled quickly and accurately. It is difficult.

From the background as described above, the present applicant has developed the method and apparatus of Patent Document 1 as a configuration in which the temperature in the reaction vessel is controlled by a heating medium or a cooling medium passed through the jacket. In this configuration, the reaction temperature of the liquid in the tank is measured, and a plurality of valves provided on the jacket are opened and closed to change the amount of the heat medium or the amount of the cooling medium to control the reaction temperature accurately. is there.
JP 2004-209432 A

  In the configuration of Patent Document 1 described above, the temperature in the tank can be controlled by changing the amount of the heat medium or the amount of the cooling medium in the jacket, so that it can be heated or cooled relatively quickly so as to correspond to the target temperature. In addition, thermal fatigue of the reaction tank itself, which is a drawback when using a heat medium or a cooling medium, can be suppressed. However, in this configuration, when applied to a dehalogenation treatment reaction in which an organic halogen compound is decomposed by dropping and reacting an oil to be treated containing an organic halogen compound to an alkali metal dispersion stored in a tank, There is a limit due to a time lag or the like in maintaining the target temperature more accurately and quickly with respect to the rapid temperature fluctuation of the liquid in the tank. For example, the flow rate (cc / sec) of the oil to be treated must be suppressed. Therefore, efficient processing becomes impossible. An object of the present invention is a tank that is suitable for a dehalogenation treatment reaction in which a change in heat generation is particularly large in a configuration in which the temperature in the tank is maintained and controlled at a predetermined temperature by a heating medium or a cooling medium passed through the jacket. It is to be able to control the internal temperature more accurately and quickly.

In order to achieve the above object, the invention according to claim 1 is characterized in that the reaction vessel has a jacket, and the organic oil is added to the alkali metal dispersion stored in the vessel by dropping and reacting the oil to be treated. A dehalogenation treatment reaction for decomposing a halogen compound, and a temperature control method for maintaining a temperature in a tank at a predetermined temperature by a heating medium or a cooling / heating medium entering / exiting the jacket, wherein a part of the oil to be treated is First heating that is set for primary dripping and is heated to a first reference temperature (for example, a range of 110 to 150 ° C.) by passing a heat medium through the jacket of the reaction tank and setting the temperature in the tank in advance. And after the first reference temperature is reached, a heating medium in the jacket is extracted, a primary dropping process in which a part of the oil to be treated is primarily dropped, and a temperature in the tank after the primary dropping. In advance From the stage at which a predetermined second reference temperature (for example, a range of 150 to 190 ° C.) is reached, a cooling medium is passed through the jacket, and the second reference temperature of the oil to be treated is maintained while substantially maintaining the second reference temperature. It is characterized by passing through a secondary dropping step of dropping.
In the above temperature control method, the first reference temperature is set to be at least 20 ° C. lower than the second reference temperature (Claim 2), and even if a part of the oil to be treated is dropped first, When the internal temperature converges below the second reference temperature, the heating medium is passed through the jacket and heated to the second reference temperature, and then the heating medium in the jacket is extracted (claim 3), It is preferable to perform the second dropping and the second dropping at substantially the same dropping flow rate (Claim 4).

  An invention apparatus according to claim 5 is used in the temperature control method for dehalogenation treatment according to any one of claims 1 to 4, wherein the reaction tank supplies the oil to be treated through a valve or the like. An oil supply unit to be treated that drops into the tank, a temperature detection unit that measures the temperature in the tank, a stirring unit that mixes the liquid in the tank, an inert gas supply unit that replaces the atmosphere in the tank, and the jacket The heating medium or the cooling medium to be passed through the jacket based on the detection result of the temperature detection unit together with the heating medium supply means and the cooling medium supply means for supplying the heating medium or the cooling medium through a valve or the like. It has a control part which opens and closes the valve of the heating medium supply means and the cooling medium supply means, and opens and closes the valve of the treated oil supply part.

In the first aspect of the invention, first, when the oil to be treated is dropped first, the inside of the jacket is empty, and when the temperature in the tank rises to the second reference temperature by reaction heat, Is immediately supplied so that the temperature rise can be accurately suppressed. For example, if the cooling medium is injected after the heating medium is extracted from the inside of the jacket, the possibility that the temperature in the tank rises excessively during the extraction of the heating medium is eliminated. Next, when the oil to be treated is secondarily dropped, the temperature in the tank is kept at the second reference temperature by the cooling medium passing through the jacket, and the temperature in the tank rises to the second reference temperature or higher due to reaction heat. It is controlled not to. In other words, since the reaction temperature rises from the first reference temperature to the second reference temperature during the first dropping, the time for initial heating of the reaction tank with the heat medium is shortened to effectively use energy. Further, in the secondary dripping, the dripping amount is reduced by the primary dripping amount, and since the dripping is performed while passing the cooling medium through the jacket, it is easy to maintain the temperature in the tank as a dehalogenation treatment.

In the invention of claim 2, for example, the temperature in the tank is raised from the first reference temperature due to the reaction heat accompanying the primary dripping of the oil to be treated, but the first reference is estimated in advance in a preliminary test or the like. By setting the temperature 30 ° C. or more lower than the second reference temperature, it is possible to simplify the control for preventing the temperature from rising excessively and keeping the temperature in the tank within a predetermined range.
-In invention of Claim 3, when the temperature in a tank does not rise to 2nd reference temperature with the reaction heat accompanying primary dripping, it heats using a heat medium. This is because, for example, if the oil to be treated contains impurities, it is assumed that there will be variations in time from the start of the first drop until the initial reaction appears, and even in such a case, the reaction is maintained normally. This eliminates the possibility that if the temperature in the tank is low, the reaction time becomes long or good reaction is not maintained.
-In invention of Claim 4, the to-be-processed oil is dripped at the substantially same flow volume (amount / time), the fluctuation | variation of reaction heat is suppressed, and it becomes easy to perform temperature control by a heat medium or a cooling-heat medium by it.
In the invention of claim 5, the above temperature control method can be implemented with a simple device structure.

(Apparatus Structure) A preferred embodiment of the present invention will be described with reference to the schematic diagram of FIG. In the reaction apparatus of FIG. 1, the reaction vessel 1 has a jacket 10, and the treated oil containing the organic halogen compound is dropped and reacted with the alkali metal dispersion stored in the vessel to decompose the organic halogen compound. This is suitable for application of a temperature control method that is used in the dehalogenation treatment reaction and that maintains the temperature in the tank at a predetermined temperature by a heating medium or a cooling / heating medium entering / exiting the jacket 10. The structure is such that the reaction tank 1 has a dispersion introduction part 2 for supplying an alkali metal dispersion into the tank, a process oil supply part 3 for dropping the process oil into the tank, and a temperature at which the temperature in the tank is measured. The detection unit 4, the stirring means 5 for mixing the liquid in the tank, the gas supply part 6 for replacing the atmosphere in the tank, the discharge part 7 provided at the lower part of the tank, and the heating medium a and the cooling medium in the jacket 10 Based on the detection results of the heating medium supplying means 8 and the cooling medium supplying means 9 for supplying b and the temperature detection unit 4, for example, the heating medium a or the cooling medium b to be passed through the jacket 10 is selected and the heating medium is supplied. And a control unit 11 that drives and controls the means 8 and the cooling medium supply means 9.

  Here, the reaction vessel 1 and the jacket 10 are appropriately selected from steel (SS) and stainless steel (SUS) according to the temperature of the heat medium and the cooling medium, the facility cost, and the like.

  The dispersion introduction part 2 is provided in the upper part of the reaction tank, and allows an alkali metal dispersion to be supplied into the tank through a pipe 12a and a valve 13a from a storage part (not shown). The to-be-processed oil supply part 3 is provided in the reaction tank upper part, and enables the to-be-processed oil containing the organic halogen compound in the storage part 14 to be dripped in a tank via piping 12b, the valve | bulb 13b, etc. In this case, the valve 13b is controlled by a signal sent from the control unit 11 via the wiring 21 or the like, and the treated oil is dropped at a target flow rate (cc / sec).

  The temperature detection unit 4 measures the liquid temperature in the tank, and transmits the measurement value to the control unit 11 via the wiring 22 or the like. The structure of the temperature detection unit 4 is set so that the detection unit is immersed in the reaction solution. It is preferable that the temperature rise can be confirmed in more detail. Note that the control unit 11 selects the heating medium a or the cooling medium b to be passed through the jacket 10 based on the measurement value of the temperature detection unit 4, or selects the heating medium a or the cooling medium b as the heating medium supply unit 8 or the cooling heat. A signal is transmitted to valves (three-way valves) 18 and 28, which will be described later, so as to be supplied into the jacket 10 via the medium supply means 9 or discharged from the jacket 10.

  The agitating means 5 is arranged to penetrate in the vertical direction in the tank while supporting the upper end of the shaft with respect to the drive part such as the motor M and the gear mechanism installed at the substantially central part of the tank upper wall, and is provided with a stirring blade on the lower end side. Has a drive shaft. As the stirring mechanism, it is sufficient if the reaction solution has sufficient ability to stir the reaction solution. As the shape of the stirring blade, for example, a paddle blade or a turbine blade is preferable.

  The gas supply unit 6 is provided in the upper part of the reaction tank, and supplies an inert gas such as nitrogen or argon (not shown) from the tank into the tank through the pipe 12c, the valve 13c, and the like. Reference numeral 15 denotes an exhaust gas section, which enables gas to be discharged from the tank. For example, the discharge unit 7 discharges the solution after the decomposition treatment from the tank through the pipe 12d and the valve 13d.

  The heating medium supply means 8 includes a heating unit 16 that heats a gas or a liquid such as steam (hereinafter also abbreviated as a heating medium) to a target temperature by a heating mechanism, and a heating medium of the heating unit 16. Pipes 19 a and 19 b that can be introduced into the jacket 10 through the pump 17 and the valve (three-way valve) 18, and a pipe 20 for circulating the heat medium in the jacket 10 to the heating unit 16 in a circulating manner. In addition, the heating medium in the jacket 10 is transferred from the pipe 19b connecting the valve 18 and the lower portion of the jacket 10 to the heating section 16 through a pipe connecting the valve 18 and the heating section 16. Extract and empty. That is, in this configuration, for example, the valve 18 switches the valve direction by a signal sent from the control unit 11 via the wiring 23 and the like, and the heating medium of the heating unit 16 is introduced into the jacket 10 via the pipes 19a and 19b. In addition, it is possible to circulate from the jacket 10 to the heating unit 16 through the pipe 20, or to extract the heat medium in the jacket 10 from the pipe 19b to the heating unit 16 through the valve 18 or the like. The control unit 11 can also control the heating mechanism of the heating unit 16.

  The cooling medium supply means 9 includes a cooling unit 26 that cools a gas or a liquid such as steam (hereinafter also abbreviated as a cooling medium) to a target temperature by a cooling mechanism, and a pump 27 that cools the cooling medium of the cooling unit 26. And pipes 29a and 29b that can be introduced into the jacket 10 via a valve (three-way valve) 28, and a pipe 30 for circulating the cooling medium in the jacket 10 to the cooling unit 26 in a circulating manner. The cooling medium in the jacket 10 is extracted from the pipe 29b connecting the valve 28 and the lower portion of the jacket 10 through the pipe connecting the valve 28 and the cooling section 26 to the cooling section 26. Empty it. That is, in this configuration, for example, the valve 28 switches the valve direction by a signal sent from the control unit 11 via the wiring 24 or the like, and the cooling medium of the cooling unit 26 is introduced into the jacket 10 through the pipes 29a and 29b. Further, the cooling medium 26 is circulated from the jacket 10 through the pipe 30 to the cooling unit 26, or the cooling medium in the jacket 10 can be extracted from the pipe 29b to the heating unit 16 through the valve 18 or the like. The control unit 11 can also control the cooling mechanism of the cooling unit 26 and the like.

(Temperature Control Method) Hereinafter, using the reaction apparatus as described above, oil to be treated containing an organic halogen compound is dropped from the oil to be treated supply section 3 to the alkali metal dispersion stored in the reaction tank 1. A temperature control method that is a dehalogenation treatment reaction in which the organic halogen compound is decomposed by reacting, and the temperature in the tank is maintained at a predetermined temperature by the heating medium a or the cooling heat medium b entering and leaving the jacket 10. explain. In this temperature control method, first, depending on the total amount of the alkali metal dispersion charged in the reaction tank 1, the amount considering reaction heat as the primary dripping amount from the total amount of oil to be treated dripped from the treated oil supply unit 3 is Set for primary dripping. And as a temperature control method, the heating medium a is allowed to pass through the jacket 10 to heat the temperature in the tank to the first reference temperature, and after reaching the first reference temperature, the heat in the jacket 10 is reached. A cooling medium in the jacket 10 is extracted from the primary dropping step of extracting the medium a and dropping the set primary dropping amount of the oil to be treated and the stage in which the temperature in the tank reaches the preset second reference temperature. b is passed, and it passes through the secondary dripping process which performs the second dripping of to-be-processed oil, substantially maintaining 2nd reference temperature.

  That is, in the first heating step, the valve 18 is switched by a signal from the control unit 11 to circulate the heating medium a of the heating unit 16 through the jacket 10, that is, within the jacket via the pipe 19 b, the jacket 10, and the pipe 20. Is heated to a first reference temperature (for example, a range of 110 to 150 ° C.) set in advance. In the primary dripping step, the temperature detection unit 4 detects that the temperature in the tank has reached the first reference temperature, and based on this, the valve 18 is switched by a signal from the control unit 11, etc. The medium a is extracted to the heating unit 16 through the pipe 19b and the like. Thereafter, the set primary dropping amount of the oil to be treated is dropped from the oil to be treated supply unit 3 into the tank by switching the valve 13b by a signal from the control unit 11 or the like. In the secondary dropping step, the valve 28 is controlled by a signal from the control unit 11 from the stage where the temperature in the tank reaches a preset second reference temperature (for example, in the range of 150 to 200 ° C.) by the reaction heat due to the primary dropping. By switching the cooling medium b in the jacket 10, that is, circulating the inside of the jacket through the pipe 29 b, the jacket 10, and the pipe 30, a signal from the control unit 11 is maintained while substantially maintaining the second reference temperature. The oil to be treated is secondarily dropped into the tank from the oil to be treated supply section 3 by switching the valve 13b or the like. This secondary dripping amount is an amount obtained by subtracting the primary dripping amount from the total amount of oil to be treated which is dropped from the to-be-treated oil supply unit 3 calculated corresponding to the total amount of the alkali metal dispersion.

  Examples of the above organic halogen compounds include dioxins, polychlorinated dibenzofurans, polychlorinated benzene, DDT, BHC and the like in addition to PCB. These organic halogen compounds may be used as they are, or may be used as an organic halogen compound solution adjusted to a concentration suitable for treatment by dissolving in a solvent such as an aliphatic hydrocarbon. Moreover, as an alkali metal, sodium, potassium, lithium, cesium, and these alloys can be illustrated. The alkali metal is used in the form of a dispersion dispersed in a solvent. The alkali metal concentration in the alkali metal dispersion can be arbitrarily selected, but is preferably about 1 to 50%. The average particle size of the metal dispersion is 20 μm or less, preferably 10 μm or less.

  In this example, using the reactor substantially the same as that in FIG. 1, first, about 160 kg of electric insulating oil was dispersed in a reaction tank (a tank having a volume of 500 L), and the concentration was adjusted to 15 wt% by dispersing the electric insulating oil in the electric insulating oil. About 110 kg was charged. Then, the solution in the reaction vessel was stirred, and at the same time, a heating medium of 190 ° C. was passed through the jacket, and the reaction vessel was heated. At the same time that the temperature in the reaction vessel rose to 130 ° C., all the heat medium in the jacket was extracted, and after confirming that it was extracted, 15 kg of electrical insulating oil whose PCB concentration was adjusted to 50 wt% was primarily dropped at a constant flow rate. did. After that, it was confirmed that the temperature in the reaction vessel suddenly increased due to an exothermic reaction, and the temperature in the reaction vessel gradually increased around 160 ° C, and at the same time, a 80 ° C cooling medium was passed through the jacket, and the reaction vessel Secondary dripping was started while the inside was cooled. The secondary dropping was performed at the same dropping flow rate as the primary dropping. The reaction was carried out while passing the cooling medium until the end of the second addition. There was almost no change in the temperature in the reaction vessel, and a smooth decomposition treatment reaction was performed at around 165 ° C., and the second dropping was completed. FIG. 2 shows the temperature in the reaction tank in the process of secondary dropping from the start of primary dropping in which time and temperature are plotted in the above examples.

As described above, the present invention only needs to satisfy the requirements specified in the claims, and the details can be variously modified or developed with reference to the above embodiments and examples.

It is a schematic block diagram which shows typically the reaction apparatus of invention form. It is a graph which shows the relationship between the time of an Example, and temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reaction tank 2 ... Dispersing body introduction part 3 ... Oil to be processed supply part 4 ... Temperature detection part 5 ... Stirring means 8 ... Heating medium supply means 1 ... Cooling medium supply means 10 ... Jacket 11 ... Control parts 13a-13d ... Valve (Solenoid valve, etc.)
18, 28 ... Valve (three-way valve, etc.)

Claims (5)

The reaction vessel has a jacket, and is a dehalogenation treatment reaction in which the organic halogen compound is decomposed by dropping and reacting an oil to be treated containing an organic halogen compound to the alkali metal dispersion stored in the vessel. In the temperature control method for maintaining the temperature in the tank at a predetermined temperature by a heating medium or a cooling / heating medium entering / exiting the jacket,
A part of the oil to be treated is set for primary dripping,
A first heating step in which a heating medium is passed through the jacket of the reaction tank to heat the temperature in the tank to a preset first reference temperature;
After reaching the first reference temperature, a heating medium in the jacket is extracted, and a primary dropping process in which a part of the oil to be treated is dropped first,
After the primary dripping, from the stage where the temperature in the tank reaches a preset second reference temperature, a cooling medium is passed through the jacket, and the oil to be treated is maintained while substantially maintaining the second reference temperature. A temperature control method in a dehalogenation treatment reaction, wherein a secondary dropping step of performing secondary dropping is performed.   2. The temperature control method in a dehalogenation treatment reaction according to claim 1, wherein the first reference temperature is set at least 20 ° C. lower than the second reference temperature.   Even if a part of the oil to be treated is dropped first, if the temperature in the tank converges at a second reference temperature or lower, the heating medium is passed through the jacket and heated to the second reference temperature. The temperature control method in the dehalogenation treatment reaction according to claim 1 or 2, wherein the heat medium in the jacket is extracted.   The temperature control method in the dehalogenation treatment reaction according to any one of claims 1 to 3, wherein the primary dropping and the secondary dropping are performed at substantially the same dropping flow rate. It is used for the temperature control method in the dehalogenation process in any one of Claim 1 to 4,
The reaction tank includes a process oil supply unit that drops the process oil into the tank via a valve, a temperature detection unit that measures the temperature in the tank, a stirring unit that mixes the liquid in the tank, Along with an inert gas supply unit that replaces the atmosphere in the tank, a heating medium supply means and a cooling medium supply means for supplying a heating medium and a cooling medium into the jacket via a valve,
Based on the detection result of the temperature detection means, the heating medium or the cooling medium to be passed through the jacket is selected, and the valves of the heating medium supply means and the cooling medium supply means are opened and closed, or the oil supply section to be treated And a control unit for opening and closing the valve.

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