JP2007216166A - Method for regenerating carbon type oil adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regenerating an oil adsorbent with no need of extraction from a facility even in the case where a large quantity of oil is adsorbed. <P>SOLUTION: The regeneration method involves the washing of a carbon type oil adsorbent which is made of calcined coke and adsorbs oil with hot water at 40°C or higher or hot water at 40°C or higher and bubbled by foams. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for regenerating a carbon-based oil adsorbent. More specifically, the present invention relates to a method for regenerating a carbon-based oil adsorbent that has been used to treat oil-containing wastewater and has adsorbed oil.

Industrial wastewater and household wastewater often contain oil. For example, oil refined wastewater is discharged from various facilities at refineries. Moreover, in the vegetable oil manufacturing factory, the wastewater containing fats and oils is discharged | emitted with manufacture of soybean oil, rapeseed oil, corn oil, etc. In addition, water-soluble cutting oil (mineral oil) is used for cooling and lubrication of the cutting surface in manufacturing factories that use many machine tools such as automobile factories, and wastewater containing this water-soluble mineral oil is discharged. It may be discharged from the manufacturing plant. Furthermore, oily wastewater having a relatively high concentration derived from animal and vegetable oils is discharged from food factories, hotels, restaurants, and the like. Therefore, when processing these oil-containing wastewater, it is necessary to remove oil from the wastewater.
As a means for removing oil from wastewater, activated carbon has been used more than ever. However, when activated carbon is used for wastewater treatment, it is possible to backwash with a small amount of oil, but backwashing with industrial water, etc. is possible. Therefore, there is no choice but to carry out a regeneration method by such steam activation. For this reason, even when a large amount of oil is adsorbed, there has been a strong demand for a method of regenerating the adsorbent without removing it from the equipment.

  The present invention has been made in view of such a situation, and a specific carbon-based oil adsorbent is used as an oil adsorbent, and the carbon-based oil adsorbent adsorbed with oil is washed by a specific method. By doing so, a cleaning process is possible without extracting the oil adsorbing material from the oil adsorption processing facility, and a method with excellent cleaning efficiency is provided.

That is, the present invention is a carbon-based oil characterized in that a carbon-based oil adsorbent composed of calcined coke adsorbed with oil is washed with warm water of 40 ° C. or higher or warm water of 40 ° C. or higher including bubbling by bubbles. The present invention relates to a method for regenerating an adsorbent.
Further, the present invention is the carbon described above, wherein the carbon-based oil adsorbent is calcined coke having a specific surface area of 20 m ² / g or less obtained by calcining coke at 1000 to 1500 ° C. The present invention relates to a method for regenerating a system oil adsorbent.

  Since the method of the present invention can regenerate the oil adsorbent without extracting the adsorbent from the oil adsorption treatment facility even when the oil content is large, its industrial value is extremely large.

Hereinafter, the present invention will be described in detail.
The carbon-based oil adsorbent used in the present invention comprises calcined coke obtained by calcining a carbonaceous material.
The carbonaceous material used as a raw material is not particularly limited, but from the viewpoint of imparting surface characteristics such that water is easily desorbed and oil is easily adsorbed to an oil adsorbent obtained by calcination, coke or graphite. It is preferable to use a non-porous material such as (including expanded graphite), particularly coke.

  Coke that is preferably used in the present invention is not particularly limited, heavy oil such as atmospheric residual oil, vacuum residual oil, tar sand, bitumen, shale oil, fluid catalytic cracker residual oil, coal tar, coal tar pitch, etc. Coal-based or petroleum-based coke obtained from the raw material, or charcoal-based coke obtained from the raw material such as wood, sawdust, and coconut. These raw materials may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, it does not restrict | limit especially as a coking process at the time of manufacturing coke, A fluid coking process, a flexi coking process, a delayed coking process, etc. are applicable. The heat treatment temperature in the coking process is usually 400 to 600 ° C. In the present invention, needle coke obtained through a delayed coking process is preferably used.

The treatment temperature when calcining the carbonaceous material is preferably in the range of 1000 to 1500 ° C, more preferably 1200 to 1450 ° C, and even more preferably 1300 to 1400 ° C. If the treatment temperature is less than 1000 ° C., sufficient hydrophobicity cannot be imparted to the surface of the resulting oil adsorbent. On the other hand, when the treatment temperature exceeds 1500 ° C., it becomes difficult to achieve a hydrophilic-hydrophobic balance where water is easily desorbed and oil is easily adsorbed on the surface of the resulting oil adsorbent. Moreover, the processing time at the time of performing calcination is preferably 1 minute to 5 hours, more preferably 5 minutes to 3 hours.
In order to efficiently perform the calcination step, it is preferable that the rate of temperature increase when the temperature is raised to the treatment temperature is 180 to 220 ° C./h.

As an apparatus for calcining the carbonaceous material, for example, a horizontal calcination apparatus such as a rotary kiln or a vertical calcination apparatus such as a lead hammer furnace or a rotary hearth (rotary hearth calsiner) may be used. it can.
The atmosphere for calcination is not particularly limited as long as polar groups can be removed from the surface of the carbonaceous material, but it is preferably performed in an inert gas atmosphere such as nitrogen.

  In addition, when cooling the calcined coke after the calcining treatment, the temperature near the outlet of the calcining apparatus may be set to 500 ° C. or less from the viewpoint of preventing the calcined coke from being oxidized and suppressing the formation of polar groups. Preferably, it is 300 degrees C or less. The cooling method is not particularly limited, and natural cooling or the like may be performed by leaving it alone, but it is preferable to perform forced cooling by water cooling from the viewpoint of further improving the processing efficiency.

For example, when coal-based, petroleum-based or charcoal-based coke is calcined at 1000 to 1500 ° C., the BET surface area of the obtained calcined coke (calcined coke) is usually 20 m ² / g or less, preferably 1 to 10 m ^2. / G. Thus, the calcined coke used in the present invention has a smaller surface area than conventional activated carbon and activated coke. However, according to the study by the present inventors, the adsorbent composed of such calcined coke exhibits higher adsorbing ability than the conventional activated carbon or activated coke for the oil content in the oil-containing wastewater. Such a comparison also suggests that the adsorptive capacity of the adsorbent of the present invention is due to the properties of the surface modified by calcination.

  The method for bringing the carbon-based oil adsorbent made of calcined coke used in the present invention (hereinafter also referred to as the present adsorbent) into contact with the oil-containing wastewater is not particularly limited. For example, activated carbon used for conventional wastewater treatment A method of filling the treatment tank similar to the adsorption tank with the present adsorbent and passing the oil-containing wastewater into the treatment tank can be mentioned. In this case, treatment conditions such as the adsorbent filling amount, water flow rate, treatment temperature, and the like can be appropriately selected in consideration of the adsorbent adsorption capacity, the oil content in the waste water, and the like. Further, the water flow may be either a downward flow or an upward flow, but the downward flow is preferable because the adsorbent can be easily regenerated by backwashing (upflow).

  Moreover, when filling this adsorbent into a treatment tank and passing oil-containing wastewater, filtration and microbial treatment are performed to remove other substances such as suspended solids (SS), COD, and BOD contained in the oil-containing wastewater. Further, it may be combined with a processing means such as coagulation precipitation, chemical oxidation (ozone oxidation or the like). In particular, when a substance such as SS that shows adsorptivity to carbonaceous materials is contained in the oil-containing wastewater, remove SS by sand filtration or the like before bringing the wastewater into contact with the adsorbent. Is preferred. If wastewater containing SS is brought into contact with the present adsorbent as it is, there is a possibility that the adsorption capacity of the present adsorbent is impaired by SS.

  When a large amount of oil is contained, it is preferable to remove the oil as much as possible by an oil-water separation operation or the like before bringing the waste water into contact with the adsorbent. Conventional activated carbon and activated coke do not show sufficient adsorption capacity for oil when the oil-containing wastewater is an emulsion or when the oil content in the oil-containing wastewater is low. However, in order to show a good adsorption capacity, the oil content from the waste water can be removed more efficiently and with high accuracy by combining with the above-described oil / water separation operation.

In the present invention, the carbon-based oil adsorbent comprising calcined coke adsorbed with oil as described above is regenerated by washing with warm water of 40 ° C. or higher or warm water of 40 ° C. or higher including bubbling by bubbles. .
That is, in the present invention, in order to promote the desorption of the adsorbed oil, heated water is used as the washing water at the time of regeneration for the purpose of reducing the viscosity of the oil. The temperature of the washing water is 40 ° C. or higher, and a range of 60 to 100 ° C. is more preferable. Furthermore, by using the operation of bubbling steam, nitrogen gas or the like in warm water, the desorption efficiency of oil or the like can be further promoted by the action of bubbles.

When the adsorbent according to the present invention adsorbs oil, it is not clear why the adsorbed oil can be easily desorbed by applying hot water of 40 ° C. or higher, but the adsorbent used in the present invention is not Unlike conventional micropores, the structure is mainly composed of large pores and cracks of 50 nm to 300 μm corresponding to macropores, and the structure is different from the conventional product having a specific surface area of 20 m ² / g or less. Therefore, the adsorption of oil is occurring in the macropores, and therefore, the contact between the washing water and the adsorbed oil during regeneration is more than in the case of activated carbon mainly composed of conventional micropores. It is assumed that it happens easily.

In the present invention, the cleaning (regeneration) treatment can be performed without extracting the oil adsorbent from the oil adsorption treatment facility.
The flow direction of the washing water may be either a downward flow or an upward flow, but backwashing (upflow) is preferred from the viewpoint of easy regeneration of the adsorbent.

In addition, the form of the cleaning treatment is not particularly limited as long as it can perform hot water cleaning at 40 ° C. or higher, or hot water cleaning at 40 ° C. or higher including bubbling with bubbles. Can do.
For example, in batch-type bubbling, a method in which steam, nitrogen gas, or the like is circulated from a lower portion of a packed bed filled with warm water, and then the warm water is removed can be employed. Further, it is possible to adopt a method in which the breakthrough adsorbent is taken out into another container, warm water is added, washing is performed while stirring, steam, nitrogen gas or the like is circulated and bubbled, and then the warm water is removed.
In the flow type, it is possible to adopt a method in which the gas amount / washing water ratio is normally 0.01 to 10 volume ratio, preferably 0.1 volume ratio or more.
Although the adsorbent itself has a gas dispersion action, a porous dispersion plate or the like may be provided below the packed bed as necessary.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Example 1]
In an inert gas atmosphere, needle coke (S-JA calcined powder coke) was heated to 1300 ° C. at a temperature increase rate of about 3 to 4 ° C./min and calcined at 1300 ° C. for 4 hours. Then, forced cooling by water cooling was performed, the exit temperature of the calcination furnace was maintained at 120 ° C., and calcined coke having a BET surface area of 3 m ² / g was obtained. When 100 cc of this calcined coke was packed in a column (capacity: 150 cc) and water containing oil was passed until the calcined coke broke through, the amount of oil finally adsorbed was 45000 mg / L.
Next, washing water at 60 ° C. was passed upward at a rate of 100 cc / min through the column filled with the calcined coke that had broken through by the waste water treatment. The residual oil content in the obtained regenerated adsorbent was 5700 mg / L. Therefore, the oil desorption amount was 39300 mg / L, and the oil desorption rate was 87%, indicating an excellent desorption ability.

[Example 2]
In Example 1, from the lower part of the calcined coke packed bed, nitrogen was introduced at 100 cc / min while bubbling, and 60 ° C. washing water was passed upward at a rate of 100 cc / min. As a result of the regeneration process, the amount of residual oil in the regenerated adsorbent was 1500 mg / L. The oil desorption rate was 97%, and an excellent effect by steam bubbling was recognized.

[Example 3]
In Example 1, when the regeneration treatment was performed in the same manner as in Example 1 except that the temperature of the washing water was 100 ° C., the residual oil content in the regenerated adsorbent was 4000 mg / L. The oil desorption rate was 91%, and the effect of increasing the temperature of the washing water was recognized.

[Example 4]
In Example 1, waste water treatment was performed in the same manner as in Example 1 except that washing water at 100 ° C. was passed while steam bubbling. As a result, the amount of residual oil in the regenerated adsorbent was 400 mg / L. It was. The oil desorption rate was 99%, indicating extremely excellent desorption ability.

[Comparative Example 1]
In Example 1, when the regeneration treatment was performed in the same manner as in Example 1 except that the temperature of the washing water was 20 ° C., the residual oil content in the regenerated adsorbent was 15400 mg / L. The oil desorption rate was 66%, and the desorption ability was inferior to that of Example 1.

[Comparative Example 2]
In Example 1, when the regeneration treatment was performed in the same manner as in Example 1 except that the temperature of the washing water was 30 ° C., the residual oil content in the regenerated adsorbent was 14000 mg / L. The oil desorption rate was 69%, and the desorption ability was inferior to that of Example 1.

[Comparative Example 3]
Commercially available activated carbon (trade name: Dazai activated carbon GM130A, manufactured by Nimura Chemical Industry Co., Ltd., BET surface area: 1000 m ² / g) was used as an adsorbent, and 100 mL of this commercially available activated carbon was packed in a column (capacity: 150 mL) to obtain Was added until the activated carbon broke through, and the amount of oil finally adsorbed was 15300 mg / L. As a regeneration method using the broken activated carbon, wash water at 30 ° C. was passed upward at a rate of 100 cc / min. The amount of residual oil in the obtained regenerated activated carbon adsorbent was 5200 mg / L. The oil desorption rate was 66%, and the desorption ability was inferior compared to the examples.

[Comparative Example 4]
In Comparative Example 3, regeneration treatment was performed in the same manner as in Comparative Example 3 except that washing water at 60 ° C. was passed while steam bubbling. As a result, the amount of residual oil in the obtained regenerated activated carbon adsorbent was 4700 mg. / L. The oil desorption rate was 66%, and the desorption ability was inferior compared to the examples.

The results of Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Tables 1 and 2.
From Table 1 and Table 2, the calcined coke according to the present invention is used as the adsorbent, and it is efficiently and easily performed by washing with warm water at 40 ° C. or higher as a regeneration method or warm water washing including bubbling with bubbles. It is clear that the adsorbent can be regenerated.

[Example 5]
Using the regenerated adsorbent obtained in Example 1 and Example 4, an adsorption capacity comparison test with a new article was performed. That is, 50 cc of the regenerated product and a new adsorbent were packed in the column, treated water containing 150 mg of A heavy oil and B heavy oil in 1 L was passed through 100 cc / min, and the oil content in the passing treated water was measured. The results are shown in Table 3 and FIG.
From Table 3 and FIG. 1, the recycled product obtained in Example 1 and Example 4 showed oil adsorption performance almost equivalent to that of new calcined coke, and also showed adsorption performance superior to that of new activated carbon.

It is a figure which shows the result of a regenerated product and a new oil component adsorption ability comparison test.

Claims (2)

  A method for regenerating a carbon-based oil adsorbent, comprising washing a carbon-based oil adsorbent made of calcined coke adsorbed with oil with warm water of 40 ° C. or higher or warm water of 40 ° C. or higher including bubbling with bubbles. The carbon-based oil adsorbent according to claim 1, wherein the carbon-based oil adsorbent is calcined coke having a specific surface area of 20 m ² / g or less obtained by calcining coke at 1000 to 1500 ° C. How to play.

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