Method for producing refined oil

Abstract

To provide a method for producing refined oil with reduced chlorine concentration from a mixed oil. [Solution] A method for producing refined oil in which the concentration of the chlorine compound is reduced from a mixed oil containing a chlorine compound and an organic liquid, comprising: a vaporization step of vaporizing the organic liquid in the mixed oil and not vaporizing a portion of the chlorine compound to separate a residue containing the chlorine compound at a higher concentration than the mixed oil; a filter passing step of passing the mixed gas of the vaporized organic liquid and the vaporized chlorine compound through a filter containing a metal oxide to separate the chlorine compound from the mixed gas; and a condensation step of condensing the mixed gas after the filter passing step to obtain refined oil.

Description

Technical Field

[0001] The present disclosure relates to a method for producing refined oil.

Background Art

[0002] Conventionally, a treatment method for treating mixed oil derived from waste plastics to reduce the chlorine concentration has been studied.

[0003] [[ID=I5]] For example, Patent Document 1 discloses a method for producing calcium chloride in which hydrogen chloride gas generated when a synthetic resin waste material containing chlorine is pyrolyzed under reduced pressure and in an oxygen-free atmosphere is suction-introduced into a liquid filter containing calcium carbonate (CaCO3), lime (CaO), or calcium hydroxide (Ca(OH)2) to generate calcium chloride in the filter section.

[0004] Further, Patent Document 2 discloses adding a calcium compound to a chlorine-containing plastic waste material, performing low-temperature dry distillation at a temperature of 300 to 350°C in a non-oxidizing atmosphere, further washing the low-temperature dry distillation residue for dechlorination, then performing high-temperature dry distillation on the washed residue at a temperature of 450 to 600°C in a non-oxidizing atmosphere, introducing the high-temperature dry distillation residue into a smelting furnace, and using the calcium content contained in the high-temperature dry distillation residue as a flux and recovering metal components other than calcium in the smelting process.

[0005] Further, Patent Document 3 discloses a waste pyrolysis treatment method in which waste containing iron, vinyl chloride, rubber, etc., such as automobile shredder dust and tires, is pyrolyzed by any method of incineration, suppressed combustion, or indirect heating from the outside for dechlorination and desulfurization during pyrolysis. In this method, a lime-based substance containing one or more of quicklime, slaked lime, and calcium carbonate is supplied together with the waste for pyrolysis, and the residue after the pyrolysis is used as a by-product raw material in the iron-making process.

[0006] Further, Patent Document 4 discloses that waste plastic containing polyvinyl chloride is placed in a reducing atmosphere at 1 kgf / cm 2A method for dechlorinating waste plastics is disclosed, which involves maintaining a temperature of approximately 200-320°C for more than one hour while stirring and mixing under a pressure of less than G, thereby melting the waste plastics and thermally decomposing the polyvinyl chloride, discharging the generated gases such as hydrogen chloride gas, and obtaining the dechlorinated molten plastic.

[0007] Furthermore, Patent Document 5 discloses a method for decomposing halogen-containing organic matter, comprising a contact step of bringing a first compound and a second compound into contact with a target object which is an organic matter containing halogens, and a heating step of heating the target object which has been brought into contact with the first compound and the second compound in an oxygen-containing atmosphere to decompose it, wherein the first compound contains an oxide semiconductor, and the second compound contains an element that reacts with halogens contained in the target object to produce a halide.

[0008] Patent Document 6 also discloses a liquefied oil production apparatus and a method for producing liquefied oil using this production apparatus, comprising: a dissolution tank for heating and dissolving organic combustible materials in heavy oil; a pyrolysis reactor for pyrolysis of the organic combustible materials in the heavy oil containing the dissolved organic combustible materials from the dissolution tank; a heavy oil separator for separating the pyrolysis products from the pyrolysis reactor from the heavy oil; a purifier for purifying the pyrolysis products separated by the heavy oil separator; and a recycling pipe for returning at least a portion of the heavy oil separated by the heavy oil separator to the dissolution tank. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 8-151213 [Patent Document 2] Japanese Patent Application Publication No. 10-60452 [Patent Document 3] Japanese Patent Publication No. 2004-267987 [Patent Document 4] Japanese Patent Application Publication No. 11-90387 [Patent Document 5] Japanese Patent Publication No. 2023-35480 [Patent Document 6] Japanese Patent Publication No. 2023-112971 [Overview of the project] [Problems that the invention aims to solve]

[0010] In the coke production process in coke ovens, diesel fuel containing chlorine compounds and organic liquids is produced as a by-product. When selling this diesel fuel externally, there are regulations regarding chlorine concentration, so it is necessary to reduce the chlorine concentration.

[0011] This disclosure was made in view of the above circumstances and aims to provide a method for producing refined oil in which a refined oil with a reduced chlorine concentration can be produced from a mixed oil. [Means for solving the problem]

[0012] This disclosure includes the following aspects: <1> A method for producing refined oil in which the concentration of the chlorine compound is reduced from a mixed oil containing a chlorine compound and an organic liquid, A vaporization step is performed to vaporize the organic liquid in the mixed oil and not vaporize a portion of the chlorine compound, thereby separating a residue containing the chlorine compound at a higher concentration than the mixed oil. A filter passing step is performed to separate the chlorine compound from the mixed gas by passing the vaporized organic liquid and the vaporized chlorine compound through a filter containing a metal oxide, A condensation step to obtain refined oil by condensing the mixed gas after the filter passing step, A method for producing refined oil, comprising the characteristics of <2> The vaporization step is a step of heating the mixed oil in an oxygen-free atmosphere to a temperature of 110°C to 140°C. <1> A method for producing refined oil as described above. <3> The filter passing step is a step of passing the mixed gas through the filter, which has been heated to a temperature of 110°C or higher and 140°C or lower. <2> A method for producing refined oil as described above. <4> The vaporization step is a step of heating the mixed oil in an oxygen-free atmosphere to a temperature that is equal to or higher than the boiling point of the organic liquid and lower than the boiling point of the chlorine compound, according to the method for producing purified oil described in <1>. <5> The filter passage step is a step of passing the mixed gas through the filter heated to a temperature that is equal to or higher than the boiling point of the organic liquid and lower than the boiling point of the chlorine compound, according to the method for producing purified oil described in <4>. <6> The filter contains, as the metal oxide, a metal oxide whose function of separating the chlorine compound from the mixed gas is regenerated by heating, according to the method for producing purified oil described in any one of <1> to <5>. <7> The metal oxide is at least one selected from the group consisting of ZnO, Cu2O, and Fe3O4, according to the method for producing purified oil described in any one of <1> to <6>. <8> The chlorine concentration in the mixed oil is 20 ppm or more and 150 ppm or less, and the chlorine concentration in the purified oil is 10 ppm or less, according to the method for producing purified oil described in any one of <1> to <7>. <9> The ratio of the chlorine concentration in the purified oil to the chlorine concentration in the mixed oil is 10% or less, according to the method for producing purified oil described in any one of <1> to <7>.

Advantages of the Invention

[0013] According to the present disclosure, it is possible to provide a method for producing purified oil capable of producing purified oil with a reduced chlorine concentration from mixed oil.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic diagram showing a purification apparatus for carrying out the method for producing purified oil according to an embodiment of the present disclosure. [Figure 2] It is a schematic diagram showing an apparatus for recycling waste plastic and by-producing light oil. [Figure 3] This is a schematic diagram showing another embodiment of a refining apparatus for carrying out a method for producing refined oil according to the present disclosure. [Figure 4] This is a schematic diagram showing the vaporization apparatus used in Experimental Example 1. [Figure 5] This graph shows the progression of chlorine concentration in the recovered oil and residual oil obtained in Experimental Example 1. [Figure 6] This is a schematic diagram showing the filter device used in Experimental Example 2. [Figure 7] This graph shows the chlorine concentration of the recovered solution obtained in Experimental Example 2. [Modes for carrying out the invention]

[0015] The following describes an example of an embodiment of this disclosure. These descriptions and experimental examples are illustrative of embodiments and do not limit the scope of the invention. In this specification, a numerical range represented by "~" means a range that includes the numbers before and after "~" as lower and upper limits, unless those numbers are preceded by "greater than" or "less than". If the numbers before and after "~" are preceded by "greater than" or "less than", the numerical range means a range that does not include those numbers as lower or upper limits. In the numerical ranges described stepwise within this specification, the upper limit of one stepwise numerical range may be replaced with the upper limit of another stepwise numerical range, or with the value shown in the experimental example. Similarly, the lower limit of one stepwise numerical range may be replaced with the lower limit of another stepwise numerical range, or with the value shown in the experimental example. Furthermore, unless otherwise specified, the percentage (%) used for content refers to "mass%". A percentage of "0" indicates that the component is optional and does not need to be included.

[0016] Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition. The term "process" includes not only independent processes, but also any process that cannot be clearly distinguished from other processes, as long as its intended function is achieved.

[0017] <Method for producing refined oil> The method for producing refined oil according to the embodiments of this disclosure is a method for producing refined oil in which the concentration of the chlorine compound is reduced from a mixed oil containing a chlorine compound and an organic liquid. The method for producing refined oil comprises a vaporization step in which the organic liquid in the mixed oil is vaporized while a portion of the chlorine compounds are not vaporized, thereby separating the residue containing chlorine compounds at a higher concentration than the mixed oil; a filtering step in which the mixed gas of the vaporized organic liquid and the vaporized chlorine compounds is passed through a filter containing a metal oxide to separate the chlorine compounds from the mixed gas; and a condensation step in which the mixed gas after the filtering step is condensed to obtain refined oil.

[0018] In the method for producing refined oil according to the embodiment of this disclosure, the raw material mixed oil is, for example, a mixed oil derived from waste plastics (i.e., a mixed oil obtained by thermal decomposition of chlorine-containing waste plastics).

[0019] During the coke production process in coke ovens, diesel fuel is produced as a by-product. This diesel fuel is a mixture of chlorine compounds and organic liquids. Coke ovens also process waste plastics, and the chlorine compounds derived from polyvinyl chloride (PVC) contained in these waste plastics remain in the diesel fuel, increasing its chlorine concentration. Strict standards for chlorine concentration are regulated for the sale of such mixtures. Therefore, it is necessary to reduce the chlorine concentration in the liquid products generated during the thermal decomposition of waste plastics and in the diesel fuel containing them.

[0020] In contrast, in the method for producing refined oil according to the embodiment of this disclosure, refined oil is produced from a mixed oil through the vaporization step, filter passage step, and condensation step described above. In the vaporization step, some of the chlorine compounds contained in the mixed oil are separated as residues without being vaporized, thereby reducing the chlorine concentration. Furthermore, in the filter passage step, the mixed gas vaporized in the vaporization step is passed through a filter containing a metal oxide, thereby separating the chlorine compounds and reducing the chlorine concentration.

[0021] According to the method for producing refined oil according to the embodiment of this disclosure, refined oil with a reduced chlorine concentration can be produced from a mixed oil by going through the above steps.

[0022] The method for producing refined oil according to the embodiments of this disclosure will be described in detail below.

[0023] Figure 1 shows an example of a refining apparatus for carrying out the method for producing refined oil according to the embodiment of this disclosure. Figure 1 is a schematic diagram showing a refining apparatus for carrying out the method for producing refined oil.

[0024] In the refining apparatus 10, first, the mixed oil 2 to be dechlorinated is injected into the vaporization equipment 12. The mixed oil 2 contains at least an organic liquid and a chlorine compound. The mixed oil 2 is indirectly heated by a heater 14 (vaporization process). For example, by heating the oil 2 to a temperature above the boiling point of the organic liquid and below the boiling point of the chlorine compound, the organic liquid in the mixed oil 2 vaporizes, while at least a portion of the chlorine compound does not vaporize. As a result, a residue (not shown) containing chlorine compounds at a higher concentration than the mixed oil 2 is separated.

[0025] Next, the mixed gas containing the vaporized organic liquid and the chlorine compound is passed through an oxide filter 16 containing a metal oxide (filter passage step). The chlorine compound in the mixed gas is physically and / or chemically adsorbed onto the metal oxide, separating the chlorine compound from the mixed gas and further reducing its chlorine content. It is preferable to heat the oxide filter 16 to prevent the mixed gas from condensing as it passes through it.

[0026] The mixed gas after passing through the oxide filter 16 is cooled and condensed by the cooler 18 (condensation step) to obtain the chlorine-reduced refined oil 4. According to the method for producing refined oil according to the embodiment of this disclosure, the chlorine-reduced refined oil can be produced in a single pass (i.e., through a series of manufacturing steps).

[0027] Furthermore, in the coke production process in coke ovens, the diesel fuel produced as a by-product by recycling waste plastics (for example, by reducing their molecular weight) is primarily derived from coal. Examples of organic liquids contained in such diesel fuel and other mixed oils include toluene, benzene, and xylene.

[0028] Furthermore, mixed oils containing diesel fuel and other components contain chlorine compounds. Waste plastics contain polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC), and from PVC and PVDC, mixed oils contain chlorine compounds such as aromatic chlorine compounds and alkyl chloride compounds.

[0029] Now, let's explain each step.

[0030] (Vaporization process) In the vaporization process, the organic liquids in the mixed oil are vaporized, while some of the chlorine compounds are not vaporized, thereby separating the residue that contains chlorine compounds at a higher concentration than the mixed oil.

[0031] Methods for vaporizing organic liquids include heating and vacuuming. Heating is preferred as the vaporization method due to its simplicity.

[0032] Mixed oils contain typical chlorine compounds, such as chlorobenzene. Chlorobenzene has a boiling point of approximately 132°C, while toluene, a typical component of organic liquids, has a boiling point of approximately 110°C. Thus, since the boiling points of organic liquids are generally lower than those of chlorine compounds, heating the mixed oil causes the organic liquid to vaporize first. As a result, some of the chlorine compounds remain unvaporized and can be separated as residue.

[0033] When the vaporization process is carried out by heating, it is preferable to heat the mixed oil to a temperature above the boiling point of the organic liquid but below the boiling point of the chlorine compound. By heating the mixed oil to a temperature above the boiling point of the organic liquid but below the boiling point of the chlorine compound, the amount of chlorine compound that is separated as a residue without vaporizing can be increased.

[0034] Furthermore, if the mixed oil contains multiple types of chlorine compounds, "below the boiling point of a chlorine compound" means below the boiling point of at least one of the chlorine compounds contained. Preferably, "below the boiling point of a chlorine compound" means below the boiling point of the chlorine compound that is present in the largest amount by mass, and more preferably, below the boiling point of all chlorine compounds contained in the mixed oil.

[0035] In some cases, the components of at least one of the organic liquids and chlorine compounds contained in the mixed oil may not be known. In such cases, when the vaporization process is carried out by heating, it is preferable to heat the mixed oil to a temperature of 110°C to 140°C, and more preferably to a temperature of 110°C to 130°C. By heating the mixed oil to the above temperature range, the amount of chlorine compounds that are separated as residue without vaporization can be efficiently increased.

[0036] When the vaporization process is carried out by heating, it is preferable to heat the mixed oil in an oxygen-free atmosphere from the viewpoint of preventing combustion.

[0037] The vaporization process is preferably carried out until all of the organic liquid contained in the mixed oil has vaporized, that is, until all of the organic liquid has vaporized.

[0038] In the vaporization process, solid residue (which may contain liquid) may remain. When using light oil, a by-product of the coke production process in a coke oven, as the mixed oil, the solid residue may be used as part of the coke raw materials. In other words, the solid residue may be mixed in as part of the raw materials and placed in the coke oven.

[0039] (Filtering process) In the vaporization step, the organic liquid (preferably all organic liquids contained in the mixed oil) and some of the chlorine compounds are vaporized. In the filter passing step, the mixed gas of the vaporized organic liquid and vaporized chlorine compounds is passed through a filter containing a metal oxide. The chlorine compounds in the mixed gas are physically and / or chemically adsorbed onto the metal oxide, separating the chlorine compounds from the mixed gas and further reducing the chlorine content.

[0040] Here, we will explain the possible mechanisms of chlorine reduction in metal oxides, using ZnO as an example.

[0041] First, there is the reaction with Cl, which is an n-type semiconductor. It is known that in ZnO, a dissociation equilibrium is established in the direction of oxygen dissociation. Depending on the partial pressure of oxygen and the ambient temperature, oxygen is removed, and the excess zinc that deviates from the chemical equilibrium becomes interstitial zinc. This interstitial zinc is located slightly deeper than the conduction band and can donate electrons to the conduction band (functioning as an n-type semiconductor). + or Zn 2+ However, it is conceivable that chlorine is adsorbed by oxidative addition to the C-Cl bond of a chlorine compound, followed by the formation of zinc chloride. (Reference: Komatsu, Kazuzo et al., Journal of the Japan Ceramics Association 80, [1], 1972, 31)

[0042] Another example is the adsorption reaction on the ZnO surface. The references listed below propose an adsorption model for aromatic compounds, including chlorobenzene, onto the zinc oxide surface. This is predicted from the thermodynamic behavior during adsorption. It is preferable to pass the mixed oil through the filter while it is heated, and it is thought that, for example, chlorine compounds with high boiling points (e.g., chlorobenzene) among the components contained in the mixed oil tend to remain adsorbed on the oxide surface. In other words, it is thought that the adsorption performance can be further improved by selecting an appropriate filter temperature. (References: T. Morimoto, Y. Suda, M. Nagao, J. phys. Chem. 1985, 89, 4881-4883)

[0043] In addition, copper oxide (Cu2O), another example of a metal oxide, is known to decompose organochlorines in the presence of an oxidizing agent. Furthermore, iron oxide (Fe3O4), another example of a metal oxide, is known to promote the decomposition of organochlorines under heated conditions.

[0044] Preferably, the metal oxides included in the filter are those that are reactive with chlorine in chlorine compounds, for example, those that have electron defects on their surface in their oxide state.

[0045] Preferably, the metal oxide contained in the filter is one whose function of separating chlorine compounds from the gas mixture is regenerated by heating (for example, its adsorption capacity is regenerated). This allows the filter, whose function of separating chlorine compounds has deteriorated due to repeated use in the filter passage process, to have its function of separating chlorine compounds from the gas mixture regenerated by heating. For example, by heating the metal oxide, physically adsorbed chlorine compounds are released from the metal oxide, and the physical adsorption capacity is regenerated. Also, if zinc oxide (ZnO) has reacted with chlorine to form zinc chloride, heating and oxidizing the metal oxide separates the chlorine, and the chemical adsorption capacity is regenerated. The heating temperature when regenerating the function of separating chlorine compounds in the metal oxide is preferably in the range of 900°C to 1000°C (more preferably 930°C to 970°C). It is preferable that the heating operation (regeneration operation) to regenerate the function of separating chlorine compounds in the metal oxide be performed with the process of passing the mixed oil through the filter stopped.

[0046] From the above viewpoint, preferred examples of metal oxides include ZnO, Cu2O, and Fe3O4. Among these, ZnO is more preferred from the viewpoint of adsorption capacity.

[0047] In the filter passing process, it is preferable to heat the filter to prevent the mixed gas from condensing as it passes through the oxide filter. Specifically, in the filter passing process, it is preferable to pass the mixed gas through a filter heated to a temperature above the boiling point of the organic liquid and below the boiling point of the chlorine compound. Furthermore, in the filter passing process, it is preferable to pass the mixed gas through a filter heated to a temperature of 110°C to 140°C (more preferably 110°C to 130°C).

[0048] (Condensation process) In the condensation process, the mixed gas after passing through the filter is condensed to obtain refined oil. For example, if the vaporization process is performed by heating, the mixed gas after passing through the filter is cooled and condensed to obtain refined oil.

[0049] According to the method for producing refined oil according to the embodiment of this disclosure, refined oil with a reduced concentration of chlorine compounds can be produced from a mixed oil containing chlorine compounds and organic liquids by going through a vaporization step, a filter passing step, and a condensation step.

[0050] Furthermore, if the chlorine concentration in the mixed oil is 20 ppm or more and 150 ppm or less, the chlorine concentration of the resulting refined oil is preferably 10 ppm or less (more preferably 5 ppm or less). Note that ppm and % representing chlorine concentration are based on mass.

[0051] Furthermore, it is preferable that the ratio of the chlorine concentration in the refined oil to the chlorine concentration in the mixed oil is 10% or less (more preferably 5% or less).

[0052] (Formation of mixed oil) Furthermore, in the coke production process in a coke oven, the diesel fuel component, which is a by-product of recycling waste plastics (for example, by reducing their molecular weight), is produced, for example, by the apparatus shown in Figure 2. In Figure 2, the waste plastic is subjected to thermal decomposition treatment by a thermal decomposition treatment apparatus 22, and then distilled in a distillation column 24. Distillation separates the tar-based material 26 from the diesel fuel component 28 (i.e., a mixed oil). By carrying out the method for producing refined oil according to the embodiment of this disclosure on the generated diesel fuel component 28, a chlorine-reduced refined oil can be obtained.

[0053] Furthermore, a vaporization step in the method for producing refined oil according to the embodiment of this disclosure may be carried out in the distillation column 24 shown in Figure 2. This embodiment will be explained with reference to Figure 3. In the apparatus shown in Figure 3, waste plastic is subjected to thermal decomposition treatment by a thermal decomposition treatment device 32, and then distilled in a distillation column 34. Distillation separates the tar-based material 36 from the light oil component (i.e., mixed oil). At this time, the heating conditions in the distillation column 34 are set to further vaporize the organic liquid from the generated light oil component while preventing the vaporization of some of the chlorine compounds (vaporization step). As a result, a residue containing a high concentration of chlorine compounds is separated from the light oil component generated in the distillation column 34. Then, a mixed gas of the vaporized organic liquid and the vaporized chlorine compounds is produced.

[0054] Next, the mixed gas is passed through an oxide filter 16 containing a metal oxide (filter passage step). The chlorine compounds in the mixed gas are physically and / or chemically adsorbed onto the metal oxide, separating them from the mixed gas and further reducing the chlorine content. It is preferable to heat the oxide filter 16 to prevent the mixed gas from condensing as it passes through it. The mixed gas after passing through the oxide filter 16 is cooled and condensed by a cooler 18 (condensation step) to obtain the chlorine-reduced refined oil 4.

[0055] To explain the effects of chlorine reduction during the vaporization process and the filter passage process, experimental examples are shown below.

[0056] (Experimental Example 1: Chlorine reduction in the vaporization process) A toluene solution containing chlorine compounds obtained from the thermal decomposition of PVC, with a chlorine concentration of 145.5 ppm derived from these chlorine compounds, was prepared. This toluene solution was heated to vaporize it, and the vaporized material was recovered by distillation. A diagram of the vaporization apparatus is shown in Figure 4. In the vaporization apparatus shown in Figure 4, the toluene solution 40 as a mixed oil was placed in a stainless steel container 42, and a heater 44 was installed to indirectly heat the stainless steel container 42. Sealed piping 48 connected the stainless steel container 42 to a cooler 46, and a recovery container 50 for recovering the recovered oil was installed after the cooler 46. The temperature of the heater 44 was set to 200°C, and the toluene solution 40 in the stainless steel container 42 was heated. Figure 5 shows the progression of chlorine concentration in the recovered oil condensed by the cooler 46 and collected in the recovery container 50, and in the residual oil remaining in the stainless steel container 42. As a result, the distilled toluene solution became 80% by volume, and the chlorine concentration in the recovered oil decreased to approximately 20 ppm. The chlorine reduction rate from toluene solution 40 (chlorine concentration 145.5 ppm) was calculated to be over 85%.

[0057] (Experimental Example 2: Chlorine reduction during the filter passage process) Light oil with a chlorine concentration of 8.2 ppm, a by-product of the coke production process in a coke oven, was heated and vaporized, passed through a metal oxide filter in its vaporized state, and then cooled and condensed for recovery. A diagram of the filter apparatus is shown in Figure 6. In the filter apparatus shown in Figure 6, 100 ml of light oil was placed in a stainless steel container 62, a heater 64 was installed to heat the stainless steel container 62, and a metal oxide filter 66 containing metal oxide 66A was installed behind the stainless steel container 62. Sealed piping connected the stainless steel container 62 to the metal oxide filter 66, and from the metal oxide filter 66 to a cooler 68. A heater capable of heating from the stainless steel container 62 to the top of the metal oxide filter 66 was installed, and the heater temperature was set to 200°C for indirect heating. The light oil vaporized by indirect heating passed through a metal oxide filter heated to 200°C to prevent condensation, and then condensed by the cooler 68 to recover the liquid. The non-condensed gas was discharged through a fume 70. When ZnO was used as the metal oxide in the metal oxide filter 66, the chlorine concentration of the recovered solution was 2.7 ppm (chlorine reduction rate of 66% or more).

[0058] Figure 7 shows the chlorine concentration of the recovered liquid, including cases where Fe3O4, Cu2O, or 1 / 3 the amount of ZnO is used as the metal oxide in the metal oxide filter 66.

[0059] Furthermore, based on the time until the end of the operation and the volume vaporized up to that point, a reaction time of 30 s to 120 s and a flow rate of 0.1 cm / s to 0.5 cm / s are preferable.

[0060] The results from Experimental Examples 1 and 2 show that the chlorine concentration in the mixed oil is effectively reduced in both the vaporization process and the filter passage process. [Explanation of Symbols]

[0061] 2 Mixed oil, 4 Refined oil, 10 Refining equipment, 12 Vaporization equipment, 14, 44, 64 Heater, 16 Oxide filter, 18, 46, 68 Cooler, 22 Pyrolysis treatment equipment, 24, 34 Distillation column, 26, 36 Tar-based, 28 Light oil component, 32 Pyrolysis treatment equipment, 40 Toluene solution, 42, 62 Stainless steel container, 48 Piping, 50 Recovery container, 66 Metal oxide filter, 66A Metal oxide, 70 Draft

Claims

1. A method for producing refined oil in which the concentration of the chlorine compound is reduced from a mixed oil containing a chlorine compound and an organic liquid, A vaporization step is performed to vaporize the organic liquid in the mixed oil and not vaporize a portion of the chlorine compound, thereby separating a residue containing the chlorine compound at a higher concentration than the mixed oil. A filter passing step is performed to separate the chlorine compound from the mixed gas by passing the vaporized organic liquid and the vaporized chlorine compound through a filter containing a metal oxide, A condensation step to obtain refined oil by condensing the mixed gas after the filter passing step, A method for producing refined oil, comprising the characteristics of

2. The method for producing refined oil according to claim 1, wherein the vaporization step is a step of heating the mixed oil to a temperature of 110°C or higher and 140°C or lower in an oxygen-free atmosphere.

3. The method for producing refined oil according to claim 2, wherein the filter passing step is a step of passing the mixed gas through a filter heated to a temperature of 110°C or more and 140°C or less.

4. The method for producing refined oil according to claim 1, wherein the vaporization step is a step of heating the mixed oil in an oxygen-free atmosphere so that the temperature of the mixed oil is above the boiling point of the organic liquid and below the boiling point of the chlorine compound.

5. The method for producing refined oil according to claim 4, wherein the filter passing step is a step of passing the mixed gas through a filter that has been heated to a temperature above the boiling point of the organic liquid and below the boiling point of the chlorine compound.

6. The method for producing refined oil according to claim 1, wherein the filter contains a metal oxide whose function of separating the chlorine compound from the mixed gas is regenerated by heating.

7. The aforementioned metal oxide is ZnO, Cu ２ O, and Fe ３ O ４ A method for producing refined oil according to claim 1, wherein the method is at least one selected from the group consisting of the following:

8. The method for producing refined oil according to claim 1, wherein the chlorine concentration in the mixed oil is 20 ppm or more and 150 ppm or less, and the chlorine concentration in the refined oil is 10 ppm or less.

9. The method for producing refined oil according to claim 1, wherein the ratio of the chlorine concentration in the refined oil to the chlorine concentration in the mixed oil is 10% or less.

Images