JP2006187750A - Sulfate pitch treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sulfate pitch physicochemical treatment method which aims to convert sulfate pitch, hazardous waste, generated at the manufacturing of illegal light oil, and the like, into a product with a low environmental load by efficient and low-cost detoxification treatment and aims to obtain valuable material. <P>SOLUTION: Electrolyzed reduced water 4 (alkaline water generated on a cathode when electrolysis is carried out after adding an electrolysis auxiliary agent, such as common salt, in a water-flow type electrolyzer) is supplied to the sulfate pitch 1, and the sulfate pitch 1 is solubilized by using an ultrasonic irradiation means 5 with a warming means 6. Subsequently water 8 is removed by an oil-water separation means 7, and then sludgy oil 11 of which the viscosity is decreased is treated in a main treatment device 12 comprising one of wet oxidation treatment, catalytic wet oxidation treatment, supercritical water oxidation treatment, supercritical water methanation treatment, and supercritical water gasification or hydrogenation treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

Detailed Description of the Invention

  It is an object of the present invention to obtain a valuable product while converting sulfuric acid pitch, which is a hazardous waste generated in the production of illegal light oil, etc., to a product with low environmental impact by detoxifying efficiently and at low cost. The present invention relates to a method for physicochemical treatment of sulfuric acid pitch.

  There are methods such as solidification landfill, recovery, and incineration as methods for disposal of sulfuric acid pitch.

  Solidification landfilling is a method of adding a surfactant, quick lime powder, water and the like to sulfuric acid pitch, solidifying and solidifying the landfill. However, it is currently forbidden to cause soil and groundwater contamination.

  In the recovery method, water is added to sulfuric acid pitch, and the mixture is separated into three layers of oil, alkylsulfonic acid, and dilute sulfuric acid by heating to about 80 ° C. while blowing steam and stirring. By separating this, the oil neutralizes the residual sulfuric acid, and the alkylsulfonic acid is purified and recovered. Dilute sulfuric acid is neutralized and discharged as waste water. This method is not economically profitable and has not been put to practical use.

  The incineration treatment is a method of incineration treatment after performing neutralization treatment using alkali such as slaked lime or caustic soda as pretreatment. Although this method is currently used, it is necessary to use a wet electrostatic precipitator to remove sulfuric acid fumes generated during incineration, and the use of a corrosion-resistant material makes the equipment expensive. Further, when slaked lime is used as pretreatment, the chemical cost is lower than that of caustic soda, but the cost of processing solid waste is required. On the other hand, when caustic soda is used, the chemical cost is high, but since only water-soluble salts are generated, the processing cost is low. However, reducing sodium sulfate sulfate is generated, so it cannot be discharged unless it is oxidized in an area with COD regulations.

Problems to be solved by the invention

  Sulfuric acid pitch is mainly generated in the process of refining lubricating oil, and it is generated as waste when removing impurities contained in mineral oil as raw material with concentrated sulfuric acid. Conversions are taking place, and the amount generated in major oil refineries is very small. In addition, it also occurs when reclaiming lubricating oil, but what is currently a problem with illegal dumping is the one that occurs when producing illegal light oil. When light oil is purchased as automobile fuel, the light oil tax is included in the price. On the other hand, kerosene and heavy fuel oil A are not taxed, and there are a number of cases where kerosene and heavy fuel oil A are mixed to produce light oil and tax is eliminated. In order to prevent this tax evasion, coumarin has been added as an identification agent to kerosene and A heavy oil. However, to remove this coumarin, illegal activities to sell tax oils that were washed with concentrated sulfuric acid and processed so that the raw materials were not known were rampant. What is generated from this sulfuric acid washing step is sulfuric acid pitch which is currently a problem.

  Since the manufacturer that discharges sulfuric acid pitch is aware of illegal activities, it is impossible to carry out costly processes such as incineration, and it is illegally dumped in drums. Sulfuric acid pitch is highly corrosive and will eventually cause soil and groundwater contamination. However, someone who has been dumped illegally has to deal with it. To that end, it is necessary to develop a treatment method that is cheaper than the current incineration treatment. For this purpose, it is conceivable to improve the existing processing method or to adapt it as a sulfuric acid pitch processing method by combining with an appropriate pretreatment.

Means to solve the problem

It is an object of the present invention to provide a treatment method for detoxifying sulfuric acid pitch, particularly sulfuric acid pitch discharged in connection with illegal light oil production, at low cost.
In order to achieve this object, first, as a solubilization pretreatment according to claim 1, electrolysis is carried out by replenishing electrolytic pitched water (sodium chloride etc. in a flowing water type electrolyzed water generator) with respect to sulfuric acid pitch. Supplied alkaline water). Electrolytically reduced water (strongly reduced water) has physical properties of pH 11 to 12.5 (11 or more), ORP-0.5 to -1.2 V (-0.6 V or less), and has a surface active action and an oil emulsifying action. Solubilize sulfuric acid pitch.

  In the solubilization pretreatment, the solubilization is promoted by performing heating or ultrasonic irradiation according to claim 2. Sulfuric acid pitch decreases in viscosity due to solubilization and becomes easy to flow. If left untreated, it separates into an oil layer and an aqueous layer. The aqueous layer containing sulfuric acid is neutralized by adding an alkali such as caustic soda and discharged. On the other hand, the oil layer containing hydrocarbon and alkyl sulfonic acid mainly composed of coumarin sulfonic acid becomes sludge containing water, and is then subjected to sulfuric acid pitch main treatment according to claims 1, 3, 4 and 5. These treatment methods are existing treatment methods for sludge, manure, and the like.

  The wet oxidation and catalytic wet oxidation, which are the main treatment methods in claim 1, are methods for oxidizing organic substances by blowing air into high-temperature and high-pressure water. Wet oxidation is a method that has been performed for a long time. Catalytic wet oxidation is a method developed by Osaka Gas Co., Ltd., which is more efficient than existing wet oxidation, and some practical plants are in operation. By this treatment, the oil component of sulfuric acid pitch that has been pre-solubilized is oxidized. As a result, hydrocarbons and alkyl sulfonic acids contained in the oil become carbon dioxide, water, sulfuric acid and residual ash. Since sulfuric acid is dissolved in the waste water, it must be neutralized with alkali. Residual ash is separated and removed in wastewater treatment.

  The supercritical water oxidation treatment which is the main treatment method in claim 3 is a method developed by Organo Corp., and an example in which sewage sludge is treated by this method has been reported (water and wastewater; Vol. 44 No. 10). 39-43 (2002).). Supercritical water is high-temperature and high-pressure water in a pressure state at a temperature equal to or higher than the critical point of water (temperature 374 ° C., pressure 22 Mpa). Gases such as hydrocarbons and oxygen that are hardly soluble in water at normal temperature and pressure will also dissolve in supercritical water at an arbitrary ratio. Therefore, if oxygen is passed in the presence of supercritical water, the organic substance and oxygen are sufficiently dissolved and mixed, so that the oxidation is efficiently performed. Carbon dioxide, water, sulfuric acid and residual ash are generated by this treatment of sulfuric acid pitch. Since sulfuric acid is dissolved in the waste water, it must be neutralized with alkali. Residual ash is separated and removed in wastewater treatment.

  The supercritical water methanation treatment, which is the main treatment method according to claim 4, is a method in which an organic substance is dissolved and reduced in molecular weight with supercritical water and decomposed into methane and carbon dioxide with a methanation catalyst. An example of using this method for the treatment of organic waste has been reported (Proceedings of the 13th Waste Society Research Presentation; 286-288 (2002). The main treatment of sulfuric acid pitch is methane. Carbon dioxide, sulfuric acid and residual ash, since sulfuric acid is dissolved in the waste water, it is discharged after neutralization, and the residual ash is separated and removed in the waste water treatment.

  The supercritical water gasification / hydrogenation treatment as the present treatment method according to claim 5 is a method of gasifying and hydrogenating organic waste using a catalyst in a state in which an inert gas is filled with supercritical water. is there. As the catalyst, an alkali catalyst such as potassium hydroxide or a nickel catalyst is effective. An example of obtaining a mixed gas mainly composed of hydrogen and methane from biomass waste by this method has been reported. (Proceedings of the 14th Waste Society Research Presentation; 593-595 (2003). Hydrogen, methane, sulfuric acid, reducible sulfur, etc. are generated by the main treatment of sulfuric acid pitch. Neutralization and oxidation of reduced sulfur and removal of residual ash are performed.

Embodiment of the Invention

  Specific examples of sulfuric acid pitch solubilization pretreatment and this treatment method using electrolytically reduced water according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of a sulfuric acid pitch treatment system, which is composed of a system combining sulfuric acid pitch solubilization pretreatment using electrolytically reduced water and the existing main treatment. The sulfuric acid pitch 1 enters the solubilization tank 2 and is agitated and mixed with the electrolytic reduced water 4 generated from the electrolytic water generator 3. In order to promote solubilization, ultrasonic waves are oscillated from the ultrasonic oscillator 5 and heated by the heating means 6. Thereafter, the water 8 separated by the oil / water separation means 7 is neutralized by the neutralization means 9 and discharged as treated water 10. On the other hand, the oily water-separated sludge-like oil 11 enters the treatment apparatus 12 and is stirred and mixed with high-temperature and high-pressure water 13 or supercritical water 14. Further, a material (air or catalyst) 15 necessary for oxidation or decomposition is added. After the reaction is completed, the exhaust gas 16 and the waste water 17 are discharged, and the waste water 17 is treated as waste water treatment means 18 such as neutralization, oxidation of reduced sulfur, and removal of residual ash, and then discharged as treated water 19.

The invention's effect

  By the pretreatment for solubilization of sulfuric acid pitch using the electrolytically reduced water according to the present invention, the sulfuric acid pitch is separated into sludge-like oil that is easy to flow and water containing sulfuric acid. Sludge-like oil can be converted to harmless carbon dioxide (carbon dioxide) by performing treatments such as wet oxidation, catalytic wet oxidation, or supercritical water oxidation. Alkyl sulfonic acid mainly composed of coumarin sulfonic acid becomes sulfur oxide when incinerated, and it is difficult to treat exhaust gas. On the other hand, in the present treatment, sulfur oxides are almost dissolved in water, so that the exhaust gas treatment is easy and an expensive exhaust gas treatment device is unnecessary. Wastewater can be discharged if neutralized with alkali. Although the present treatment system requires treatment of residual ash, it is also advantageous in that almost no solid waste that is difficult to dispose is produced compared to incineration. On the other hand, the sludge-like oil separated by the above-mentioned solubilization treatment is dissolved by stirring and mixing with supercritical water, and recycled as high-value combustible gas by methanation or hydrogenation using a catalyst. be able to.

Sulfuric acid pitch treatment system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sulfuric acid pitch 2 ... Solubilization tank 3 ... Electrolyzed water production | generation apparatus 4 ... Electrolytic reduction water 5 ... Ultrasonic oscillator 6 ... Heating means 7 ... Oil-water separation means 8 ... Water separated by oil-water separation 9 ... Neutralization means 10 ... Treated water 11 ... Sludge oil 12 ... This treatment device 13 ... High-temperature and high-pressure water 14 ... Supercritical water 15 ... Materials necessary for oxidation and decomposition (air and catalyst)
16 ... exhaust gas 17 ... waste water 18 ... waste water treatment means 19 such as neutralization, oxidation of reduced sulfur, removal of residual ash, etc .... treated water

Claims (5)

        For the purpose of detoxifying sulfuric acid pitch, which is a hazardous waste generated during the production of illegal diesel oil, electrolytically reduced water (electrolytic auxiliary agent such as salt is added to the sulfuric acid pitch with a flowing water type electrolyzer). By solubilizing pretreatment that injects alkaline water generated at the cathode when electrolyzed and also called strong reduced water) Fluid. A method for treating sulfuric acid pitch, characterized in that a hydrous sludge-like oil obtained by oil-water separation from this fluid is converted into carbon dioxide gas or the like by wet oxidation or catalytic wet oxidation to render it harmless.         The electrolytic pitch water is injected into the sulfuric acid pitch according to claim 1, and the emulsification is promoted by heating the electrolytic reduced water or irradiating with ultrasonic waves or using both in combination. Processing method.         After the solubilization pretreatment of sulfuric acid pitch in claim 1 and 2, the water-containing sludge-like oil obtained by oil-water separation is supercritically hydroxylated to convert it into carbon dioxide gas or the like to render it harmless. A method for treating sulfuric acid pitch.         The hydrous sludge-like oil obtained by oil-water separation after the pretreatment for the solubilization of sulfuric acid pitch in claims 1 and 2 is converted into methane and the like by decontamination by supercritical water methanation. A method for treating sulfuric acid pitch.         After the pre-solubilization treatment of sulfuric acid pitch in claims 1 and 2, the water-containing sludge-like oil obtained by oil-water separation is converted to hydrogen, methane, etc. by supercritical water gasification and hydrogenation treatment, and is harmless A method for treating sulfuric acid pitch, characterized by comprising:

Images