JP2005230704A - Method for treating oil-containing sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of economically treating oil-containing sludge produced in a steel plant, or the like, in a large quantity. <P>SOLUTION: This method for treating oil-containing sludge comprises a process of supplying oil-containing sludge which contains iron and oil occurring from steel manufacturing process to a carbonizing apparatus, a process of heating and carbonizing the oil-containing sludge in the carbonizing apparatus, a washing process of washing carbonization gas produced in the carbonizing process in a washing tank, a process of separating oil stored in the washing tank and a process of discharging carbonized material containing the iron from the carbonizing apparatus. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for treating oil-containing sludge generated in a steel manufacturing process or a steel wastewater treatment process.

  Conventionally, in steel factories, a large amount of oil such as lubricating oil is used in the manufacture and processing of steel, and a large amount of oil-containing sludge, which is a mixture of iron scrap and oil, is generated. Some of these oil-impregnated sludge is reused as a raw material for steelmaking, but sludge containing a large amount of oil, such as oil pit dredged sludge in steel plants and dredged sludge in oil-containing wastewater treatment pits, is reused as a raw material for iron making. This is difficult and must be processed by various processing methods.

  As the above treatment method, there is a method of incineration together with other industrial waste, but in this method a large amount of incineration residue is generated, and the incineration residue contains many impurities other than iron, so it should be used as an ironmaking raw material. Have difficulty. Although a cleaning method using a detergent is also conceivable, this method generates a large amount of cleaning water, and requires a lot of cost for the processing of the cleaning water, which is not practical. Further, a grinding method and a method using microorganisms are conceivable, but any of them is difficult to adopt in terms of cost.

  In addition, as a method for treating waste including general oil, etc., for example, a reduced pressure in which liquid-containing waste is dried under reduced pressure, and vapor generated from the waste during drying is introduced into the stored liquid in the treatment tank to deodorize and purify the waste. A drying apparatus has been proposed (see Patent Document 1). In addition, a processing apparatus has also been proposed in which waste is dehydrated and then carbonized by heating to a high temperature in a low-oxygen atmosphere or in a vacuum (see Patent Documents 2 to 5). These methods have a new problem of treatment of dry gas or dry distillation gas generated by drying or carbonization, and cannot be said to be effective as a method for treating oil-containing sludge.

JP 2003-19472 A JP 2000-274951 A JP 2001-276791 A JP-A-6-226234 JP-A-5-305276

  Accordingly, an object of the present invention is to provide a method for economically treating oil-containing sludge generated in large quantities in a steel factory or the like.

  The above object is achieved by the present invention described below. That is, the present invention includes a step of supplying oil-containing sludge containing iron and oil generated from a steel production process to a carbonization device, a step of heating and carbonizing the oil-containing sludge in the carbonization device, and a dry distillation generated in the carbonization step. A method for treating oil-containing sludge, comprising: a step of washing gas in a washing treatment tank; a step of separating oil accumulated in the washing treatment tank; and a step of discharging iron and carbide from the carbonization device. provide.

  As an example of the oil-containing sludge that can be treated by the above method, oil-containing sludge containing 10 to 40% by mass of iron and 5 to 20% by mass of oil can be given. The oil-containing sludge that is the object to be treated is usually in the form of clay or mud at room temperature. Therefore, in the present invention, it is preferable to heat and fluidize the oil-containing sludge and supply it to the carbonizer.

  The carbonization device has a carbonization chamber and a combustion chamber partitioned from the carbonization chamber, and is a device for heating and carbonizing the oil-containing sludge charged into the carbonization chamber with combustion heat generated from the combustion chamber. Is preferred. In addition, the water distillation treatment tank of the carbonization gas includes an ejector for simultaneously washing the carbonization gas with suction, an exhaust device for sending the gas collected above the treatment tank to the combustion chamber of the carbonization device, and a water surface of the treatment tank It is preferable to have a device for collecting the oil collected on the top and a temperature control device for adjusting the temperature of the aqueous phase in the treatment tank.

  According to the present invention, oil, iron and moisture can be easily separated and recovered from oil-containing sludge generated in large quantities in steel factories, steel factories, etc., and the recovered iron can be reused as ironmaking raw materials. The amount of oil-containing sludge to be disposed as industrial waste can be reduced to zero or drastically reduced.

Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention.
The oil-impregnated sludge to which the method of the present invention is applied is not particularly limited, and examples thereof include sludge containing a large amount of oil such as oil pit dredged sludge in steel plants and oil-containing wastewater treatment pit dredged sludge that have been conventionally treated as industrial waste. It is done. These oil-impregnated sludges vary depending on their origins, but generally contain 10 to 40% by mass of iron scrap, 5 to 20% by mass of oil, 20 to 50% by mass of moisture and residue (such as earth and sand). Usually, it is in the form of clay or mud.

  In the present invention, the oil-containing sludge as described above is supplied to a carbonization apparatus as shown in FIG. At this time, the oil-containing sludge may be directly supplied to the carbonization chamber, but preferably after a predetermined amount is charged into the storage tank 1 and heated by the heating device 2 provided in the storage tank 1 to impart fluidity to the oil-containing sludge, It is preferable to supply the carbonization chamber 4 via the supply port 3. The oil-containing sludge becomes fluid by the heating, and the water contained in the sludge is separated from the oil and collected at the bottom of the storage tank 1. By removing this water from the storage tank 1 in advance, carbonization treatment is performed. The amount of heat energy used at the time can be saved.

In the carbonization apparatus, the oil-containing sludge is carbonized. The carbonization apparatus includes a carbonization chamber 4 and a combustion chamber 5 partitioned from the carbonization chamber 4. The carbonization chamber 4 is heated to a high temperature by a burner 6 provided in the combustion chamber 5. The oil-impregnated sludge charged into the steam is steamed to carbonize the oil and other organic substances in the oil-impregnated sludge. A stirring device 7 driven by a motor M is provided in the carbonization chamber 4 so that the contents in the furnace during carbonization are uniformly stirred. In the carbonization chamber 4, the oil and other organic substances in the oil-containing sludge are pyrolyzed or dry-distilled, and part of the oil remains in the carbonization chamber 4 together with iron as carbide, and the carbide mainly composed of iron is discharged from the discharge hole 8. . In discharging the carbide, the carbide is transferred to the container 12 through a conveyor 11 having a cooling jacket 9 and a stirrer 10 in order to cool the carbide. Although the volume of the said carbonization chamber is not specifically limited, Usually, it is 1-20 m < ³ >, and it heats to about 200-400 degreeC with the heat from the combustion chamber 5 for about 2 to 4 hours, and carbonizes the content. The gas generated in the combustion chamber is exhausted from the exhaust port 13, but since the fuel used for the burner does not contain a chlorine compound or the like, the exhaust gas substantially does not contain dioxys.

In the carbonization chamber 4, the oil and organic matter in the oil-containing sludge are carbonized, and a dry distillation gas containing some water vapor is generated. Since various substances are contained in the dry distillation gas, the present invention does not release the dry distillation gas into the atmosphere, and water 21 is present inside the dry distillation gas outlet 14 as shown in FIG. It is guided to the sealed processing tank 22 stored. The introduction of the dry distillation gas into the treatment tank 22 is preferably performed by a vacuum suction machine such as an ejector 23, and the water soluble components in the dry distillation gas are dissolved in the water 21 in the treatment tank 22 by operating the ejector 23 with water. Then, since the water-insoluble oil component floats on the water surface, it is collected in the oil tank 25 using the floating oil scraper 24 or the like. The floating oil can be delivered to an industrial waste disposal company, but is preferably used as part of the fuel for the burner 6 shown in FIG. Volume of the processing tank 22 is not particularly limited, is usually 5 to 15 m ^3, the water usually 2 to 10 m ³ is stored therein.

  Since the temperature of the water 21 in the treatment tank 22 is increased by the introduction of the dry distillation gas, the treatment tank 22 is connected to the heat exchanger 26, and the temperature of the treatment water 21 is in a certain range as possible (for example, 30 to 40 ° C.). ) Is preferably retained. In order to cool the treated water, the treated water is cooled by passing through the heat exchanger 26 in which the cooling water is circulated using the pump P, and the cooled treated water is used as the water for the ejector 23. preferable. Further, the water-washed dry distillation gas accumulated in the space of the treatment tank 22 is supplied to the combustion chamber 5 shown in FIG. 1 by the exhaust fan 27, so that the organic matter contained in the gas is combusted. By configuring as described above, the treatment tank 22 can be made a completely sealed type, there is no exhaust gas from the carbonization chamber 4, and therefore the environment is not polluted by the exhaust gas.

  Since the water 21 in the treatment tank 22 has a pollutant concentration that gradually increases due to the cleaning of the dry distillation gas, fresh water is replenished as needed, and the contaminated cleaning water 21 is continuously or intermittently extracted. 21 is discharged after being subjected to wastewater treatment such as activated sludge treatment as necessary.

  By performing the above treatment, the iron content in the oil-impregnated sludge generated in a steel factory or the like contains a small amount of carbide but is concentrated to a relatively high concentration of iron scrap and can be used sufficiently as an iron-making raw material. Further, most of the oil content in the oil-containing sludge is decomposed into low molecular weight components and recovered as oil with good fluidity, and can be used as fuel for the carbonization apparatus used in the method of the present invention. Therefore, according to the present invention, oil-containing sludge, which is difficult to treat in the past, is treated as an industrial waste, and has environmental pollution, can be effectively used as a resource.

Next, the present invention will be described more specifically with reference to examples.
Example 1
The treatment was performed on 18.03 kg of oil pit sludge in the steel factory. The sludge had a water content of 39.5% by mass, an oil content of 10.1% by mass, and a residue (SS) of 50.4% by mass, and the iron content in the sludge was 21.6% by mass. First, when the sludge was put in the storage tank (with an internal volume of 0.1 m ³ , with a steam jacket) shown in FIG. 1 and heated to an internal temperature of 70 ° C. for 1 hour with the steam jacket, the oil-containing sludge became fluid. Next, the fluidized sludge was supplied from the supply port into the carbonization chamber. The specifications of the carbonization apparatus used at this time were φ1,600 × L2,500 mm, and the amount of sludge in the carbonization chamber was 18.03 kg. And the combustion chamber temperature was maintained at 900 degreeC with the burner, the carbonization chamber temperature was 300 degreeC, and the carbonization process was performed for 2 to 3 hours. Furthermore, the dry distillation gas generated by this carbonization treatment was supplied to a water washing treatment tank and treated as follows.

The washing tank has a volume of 4 m ³ and 2 m ³ of water is stored inside. The dry distillation gas was washed with water while sucking the dry distillation gas with an ejector. The water temperature in the treatment tank during the treatment was maintained at 32-35 ° C. by cooling with a heat exchanger. Further, the gas collected in the upper part of the treatment tank was continuously guided to the combustion chamber and burned by using an exhaust fan. In addition, the oil collected on the water surface in the treatment tank was collected by a floating oil scraper and accumulated in the oil tank. The total amount of carbide discharged from the carbonization apparatus was 6.96 kg, and the iron content was 56 mass%. The total amount of floating oil was 0.79 kg. The above carbide has a large iron content and can be reused by mixing with the ironmaking raw material, and the oil can be used as a fuel for the carbonization apparatus.

  According to the present invention, oil, iron and water can be easily separated and recovered from oil-containing sludge generated in large quantities in steel factories, steel factories, etc., and the recovered iron can be reused as ironmaking raw materials. The amount of oil-containing sludge to be disposed as industrial waste can be reduced to zero or drastically reduced.

The figure explaining the outline | summary of the carbonization apparatus used with the method of this invention. The figure explaining the outline | summary of the water-washing processing tank used with the method of this invention.

Explanation of symbols

1: Storage tank 2: Heating device 3: Supply port 4: Carbonization chamber 5: Combustion chamber 6: Burner 7: Stirrer 8: Discharge hole 9: Cooling jacket 10: Stirrer 11: Conveyor 12: Container 13: Exhaust port 14: Dry distillation Gas outlet 21: Water 22: Treatment tank 23: Ejector 24: Floating oil scraper 25: Oil tank 26: Heat exchanger 27: Blower

Claims (5)

  A step of supplying oil-containing sludge containing iron and oil generated from the steel production process to the carbonization device, a step of heating and carbonizing the oil-containing sludge in the carbonization device, and a carbonization gas generated in the carbonization step in a water washing treatment tank. A method for treating oil-containing sludge, comprising a step of washing with water, a step of separating oil accumulated in the washing treatment tank, and a step of discharging carbide containing iron from the carbonization apparatus.   The oil-containing sludge treatment method according to claim 1, wherein the oil-containing sludge contains 10 to 40% by mass of iron and 5 to 20% by mass of oil.   The method for treating oil-containing sludge according to claim 1, wherein the oil-containing sludge is heated and fluidized and supplied to the carbonization apparatus.   The carbonization device has a carbonization chamber and a combustion chamber partitioned from the carbonization chamber, and is a device for heating and carbonizing the oil-containing sludge charged into the carbonization chamber with combustion heat generated from the combustion chamber. Item 2. A method for treating oil-containing sludge according to Item 1.   The flushing treatment tank for the dry distillation gas has an ejector for flushing the dry distillation gas simultaneously with suction, an exhaust device for sending the gas collected above the treatment tank to the combustion chamber of the carbonization device, and on the water surface of the treatment tank. The processing method of the oil-containing sludge of Claim 1 which has the apparatus which collect | recovers the collected oil components, and the temperature control apparatus which adjusts the temperature of the water phase in a processing tank.

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