JP2006022346A - Method and apparatus for degreasing grease-containing scale - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus in which grease content stuck to the surface of grease-containing scale is safely and efficiently removed without causing any environmental problem. <P>SOLUTION: This method for degreasing grease-containing scale is characterized in that dry steam (preferably, having a steam saturation degree of 20 to 80%) superheated to a temperature at which grease is thermally decomposed or lower (preferably, 100 to 220°C) is brought into contact with grease-containing scale (e.g., scale having a grease content of ≥0.5%). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for efficiently and sufficiently deoiling oil without thermally decomposing it from an oil-impregnated scale generated at a steel mill or the like.

In steelworks and the like, a large amount of oil-impregnated scale is generated in the hot rolling process, cold rolling process, wire rod process, and the like. Since this oil-containing scale is mainly composed of iron oxide, particularly FeO or Fe ₂ O ₃ , it can be effectively reused as a raw material for iron making. However, it is necessary to remove oil as much as possible.

  If the oil content is about 0.5% or less (hereinafter referred to as “A scale”), the amount of pyrolysis products such as gas generated by thermal decomposition of the oil component is small, so the oil content scale is deoiled. It can be reused as it is as a raw material for steelmaking without treatment, but if the oil content is about 0.5% or more (hereinafter referred to as “B scale”), a large amount of thermal decomposition products are generated. Oil treatment is required.

  However, for example, the oil can be deoiled by heating the B scale to a high temperature and thermally decomposing the oil. However, since the pyrolysis products generated in large quantities can cause air pollution and the like, In addition to the deoiling treatment facility, a large-scale facility for detoxifying the pyrolysis product is required separately.

  For this reason, various deoiling treatment techniques for efficiently deoiling oil-containing scales have been proposed so far without causing environmental problems.

  For example, Patent Document 1 discloses a technique for deoiling by adding scale to an aqueous solution in which an alkali salt and a polyoxyalkylene derivative are dissolved, focusing on the fact that the oil can be washed with an alkali. Although the above technique is excellent in deoiling property, it is difficult to construct a cleaning facility including a cleaning liquid and to take time for deoiling treatment after the introduction.

  Although it is not a technique related to an oil-impregnated scale, Patent Document 2 discloses an oil component that adheres to the surface by injecting low-pressure and high-pressure high-temperature superheated steam at 150 to 600 ° C. onto the surface of a metal or non-ferrous metal material or workpiece. A technique for deoiling oil is disclosed.

  Although this technology is also excellent in deoiling property, since steam in the temperature range where the oil is thermally decomposed is sprayed onto the surface of the work piece, the oil adhering to the surface is thermally decomposed, and water that contains substances generated by thermal decomposition separately. In addition, a technology for treating gas and the like is required. After all, the above technique has a problem that the processing cost increases and an environmental protection problem.

JP 2003-27147 A JP 9-143775 A

  The present invention causes environmental problems with oil adhering to the surface of the oil-impregnated scale in view of various problems of deoiling technology by alkali cleaning (see Patent Document 1) and superheated steam injection (see Patent Document 2). It is an object of the present invention to provide a method and apparatus for deoiling safely and efficiently without any problems.

  The present inventor has intensively studied a method for efficiently deoiling oil adhering to the surface of the oil-containing scale. And this inventor pays attention to the deoiling capability of steam, in order to avoid thermal decomposition of oil, using dry steam overheated to a temperature below the temperature at which oil is thermally decomposed, the oil content is 0.5% or more A deoiling test was conducted to deoil oil from the scale (B scale).

As a result, the present inventor
(I) The oil can be sufficiently deoiled from the B scale with dry steam heated to a temperature below the temperature at which the oil is thermally decomposed; and
(Ii) that there is an optimum steam saturation range that maximizes the deoiling capacity between the deoiling capacity and steam saturation of the dry steam;
I found.

  This invention was made | formed based on the said knowledge, and the summary is as follows.

  (1) A method for deoiling an oil-impregnated scale, comprising bringing dry steam heated to a temperature equal to or lower than a temperature at which oil is thermally decomposed into contact with the oil-impregnated scale.

  (2) The oil-retaining scale deoiling method according to (1) above, wherein a temperature not higher than a temperature at which the oil is thermally decomposed is 220 ° C. or lower.

  (3) The oil-retaining scale deoiling method according to (1) or (2) above, wherein a temperature not higher than a temperature at which the oil is thermally decomposed is a temperature of 100 ° C. or higher.

  (4) The method for deoiling an oil-containing scale according to any one of (1) to (3), wherein the dry steam has a steam saturation of 20 to 80%.

  (5) The method for deoiling an oil-containing scale according to any one of (1) to (4), wherein the oil-containing scale is a scale having an oil content of 0.5% or more.

  (6) The method of deoiling an oil-containing scale according to any one of (1) to (5), wherein the air flow of the dry steam is brought into contact with the oil-containing scale.

(7) A deoiling device that performs deoiling by bringing dry steam heated to a temperature equal to or lower than a temperature at which oil is thermally decomposed into contact with an oil-containing scale,
(A) a steam superheater that superheats dry steam to a temperature below the temperature at which oil is thermally decomposed; and
(B) a deoiling treatment apparatus for deoiling by introducing superheated dry steam from the steam superheater and bringing it into contact with the oil-impregnated scale;
An oil-retaining scale deoiling device comprising:

(8) In the oil removal scale deoiling device according to (7),
(C) an oil separation and recovery device that separates and recovers oil from the oil-containing steam derived from the deoiling treatment device;
An oil-retaining scale deoiling device comprising:

  (9) In the oil-impregnated scale deoiling device according to (7) or (8), the oil-impregnated scale is continuously supplied to and discharged from the deoiling treatment device, and superheated dry steam is continuously supplied from the steam superheater. The oil-retaining scale deoiling device is characterized in that it is introduced and derived automatically.

  ADVANTAGE OF THE INVENTION According to this invention, oil can be efficiently deoiled from the oil-impregnated scale generate | occur | produced in a steel mill etc., without thermally decomposing.

  First, the deoiling method of the present invention will be described.

  The inventor uses a batch-type deoiling treatment apparatus and a flow-type deoiling treatment apparatus, using dry steam superheated to a temperature of 220 ° C. or less at which the oil component is not thermally decomposed, and changing the steam saturation in various ways. Table 1 was subjected to a deoiling test of oil-impregnated scales showing the components and oil content, and the effect of steam saturation on the deoiling rate was investigated.

Where the steam saturation is
Vapor saturation = (Vapor pressure in deoiling device / Saturated vapor pressure) × 100 (%)
It shows the humidity in the deoiling treatment apparatus. That is, if the steam saturation is low, the inside of the deoiling apparatus is more dry and the steam density is low.

  Using a batch-type deoiling treatment device, hold an oil-containing scale with an oil content of 1.40% (scale B2 in Table 1) in dry steam at 130 ° C and 170 ° C with varying steam saturation for 1 hour. The results of the deoiling test performed are shown in FIG.

  As shown in FIG. 1, the oil removal rate (in the figure, weight loss rate (%) = (initial weight of scale−weight of scale after deoiling treatment) / initial weight of scale × 100) is the steam saturation. It rises at 20 to 80% and rises remarkably at a vapor saturation of 40 to 60%.

  That is, (i) oil can be sufficiently deoiled from B scale with dry steam heated to a temperature at which the oil does not thermally decompose, and (ii) between the deoiling capacity and steam saturation of dry steam. There is an optimal steam saturation range that maximizes the deoiling capacity.

  As described above, this is a finding found by the present inventor and based on the present invention. And in this invention, based on the said test result, 20-80% of steam saturation is made into a preferable range, and 40-60% is made into the more preferable range.

  As shown in FIG. 1, since the weight loss rate when the superheated steam temperature is 130 ° C. is smaller than the weight loss rate when the superheated steam temperature is 170 ° C., the present inventor has determined the critical superheat temperature at which the deoiling phenomenon appears. For the purpose of confirmation, the relationship between the superheat temperature of the dry steam and the weight loss rate of the oil-impregnated scale was further investigated.

  In FIG. 2, using dry steam with a saturation steam degree of 40%, changing the superheated steam temperature within the range of 60 to 200 ° C., the oil content of the oil-impregnated scale with an oil content of 1.40% (scale B2 in Table 1) is The result of deoiling is shown.

  From FIG. 2, it is understood that the deoiling phenomenon occurs even at the superheated steam temperature of 60 ° C., but the deoiling rate significantly increases from 100 ° C. Therefore, in the present invention, the lower limit of the superheated steam temperature is preferably 100 ° C.

  Moreover, although it turns out that a superheated steam temperature is so high that FIG. 2 is high, in order to suppress thermal decomposition of an oil component as much as possible, in this invention, the upper limit of heating steam temperature is made into the temperature which an oil component does not thermally decompose.

  This temperature usually varies depending on the oil component, but if it is 220 ° C, the thermal decomposition of the oil component can be reliably suppressed, so the upper limit of the superheated steam temperature is preferably 220 ° C.

  Here, the reason why the oil component can be sufficiently deoiled from the oil-containing scale using the dry steam heated to a temperature at which the oil is not thermally decomposed, and the reason why the optimum range of the steam saturation of the dry steam exists will be described.

  First, FIG. 3 schematically shows a deoiling mechanism in the presence of dry steam. In this deoiling mechanism, the water particles 3 enclose the oil particles 2 adhering to the scale surface 1 and are separated from the scale surface 1 so that deoiling proceeds.

  In this way, if dry steam heated to a temperature at which the oil does not thermally decompose is used, the oil particles adhering to the scale surface can be wrapped in the state of the oil particles and separated without producing a pyrolysis product. Therefore, the scale surface can be deoiled. This is the technical idea that forms the basis of the present invention.

  Whether or not deoiling proceeds efficiently and sufficiently on the scale surface largely depends on the lipophilicity and abundance of water particles (functioning as a deoiling medium).

  Water has a property of being easily dissolved in an organic substance when the dielectric constant is lowered. Therefore, if the water particles have a low dielectric constant, the water particles have good lipophilicity, but this dielectric constant is proportional to the vapor saturation. That is, when the steam saturation of the dry steam is low, the lipophilicity of the water particles is good.

  However, the deoiling ability of the dry steam greatly depends on the density state of the steam (the amount of water particles) in the deoiling apparatus, that is, the degree of steam saturation.

  If the steam saturation of the dry steam is low in the deoiling treatment device, the dielectric constant of the water particles (deoiling medium) is low and the oleophilicity is good. Therefore, as shown in FIG. The medium) immediately adheres to the oil particles 2, but since the amount of the water particles 3 (deoiled medium) is small, the deoiling that encloses the oil particles 2 and separates from the scale surface 1 does not proceed sufficiently. After all, if the steam saturation of dry steam is low, the amount of deoiling is small.

  On the other hand, if the steam saturation of the dry steam is high in the deoiling treatment apparatus, a sufficient amount of water particles 3 (deoiling medium) are present as shown in FIG. Therefore, the water particles 3 do not function sufficiently as a deoiling medium. Rather, the water particles 3 aggregate together and deoiling does not proceed. After all, if the steam saturation of the dry steam is high, deoiling does not proceed.

  Therefore, in deoiling of oil-impregnated scale using dry steam, there are two contradictory factors: the amount of water particles (deoiling medium) responsible for separating oil from the scale surface and lipophilicity (dielectric constant). In balance, there will be an optimum range of steam saturation that maximizes the deoiling capability of the dry steam.

  The present invention is also characterized in that the optimum range of the above-mentioned saturation is found.

  Next, the deoiling device of the present invention will be described. In FIG. 7, the one aspect | mode of the deoiling apparatus of this invention is shown. In FIG. 7, the steam generated by the steam generator 4 is supplied to the steam superheater 5 and superheated to a temperature not higher than the temperature at which the oil is thermally decomposed (preferably 100 ° C. or higher and 220 ° C. or lower). At this time, the steam saturation of the overheated dry steam is appropriately adjusted to, for example, preferably 20 to 80%, and more preferably 40 to 60%.

  The superheated dry steam whose vapor saturation is appropriately adjusted is introduced into a deoiling treatment apparatus 6 containing an oil impregnated scale (for example, a scale having an oil content of 0.5% or more) to perform deoiling.

  The deoiling treatment device 6 may be either a batch type or a flow type deoiling treatment device, but the flow type is a deoiling mechanism as shown in FIG. 6, that is, the oil adhering to the scale surface 1. Deoiling can be performed more efficiently and sufficiently by a deoiling mechanism that quickly envelops the particles 3 with water particles 3 (deoiling medium) and quickly separates them from the scale surface 1 and carries them away.

  FIG. 8 shows one mode of a flow-type desulfurization processing apparatus. A predetermined amount of the oil-impregnated scale is continuously charged from the scale charging inlet 13, and moves toward the scale discharge port 14 while being stirred in the deoiling processing device as the screw 9 rotates.

  During this time, the oil-impregnated scale is fed from the steam feed screw shaft 12 and exposed to the dry steam continuously introduced from the steam inlet 11 into the deoiling processing apparatus, and deoiling proceeds.

  The oil-impregnated steam that has achieved the deoiling function is led out of the oil-removing treatment apparatus from the oil-impregnated steam outlet 15 through the filter 10 provided for separation from the fine scale.

  As shown in FIG. 7, the oil-impregnated steam derived from the deoiling processing apparatus is sent to the oil separation / recovery device 8 via the steam cooling device 7, where the oil is separated and recovered. This oil is recycled as fuel or the like.

The scale from which oil is separated and removed from the surface is composed mainly of FeO and Fe ₂ O ₃ , and the total Fe amount (T-Fe in Table 1) reaches about 70% (see Table 1). Therefore, there is a possibility that it can be used as an iron-making raw material or other iron raw materials, for example, a raw material for producing ferrite.

  Next, examples of the present invention will be described. The conditions of the examples are one example of conditions adopted for confirming the feasibility and effects of the present invention, and the present invention is limited to this one example of conditions. Is not to be done. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

Example 1
100g of oil content 1.80% scale (scale B3 in Table 1) is stored in a batch-type deoiling equipment, and superheated steam (steam saturation 40%) heated to 170 ° C is fed into the equipment. And held for 1 hour.

  As a result, the oil content was reduced to 0.2%. The scale after deoiling can be recycled as A scale.

(Example 2)
Using a flow-type deoiling treatment apparatus shown in FIG. 8, a scale having an oil content of 1.40% (scale B2 in Table 1) was deoiled. As the dry steam, dry steam having a superheating temperature of 130 to 220 ° C. and a steam saturation of 40 to 60% was used.

  The amount of dry steam to be fed and the scale residence time were adjusted as appropriate to investigate the oil removal rate.

  As a result, a scale having an oil content of 0.30% could be continuously obtained from the scale outlet. The scale after deoiling can be recycled as A scale.

  As described above, according to the present invention, oil can be efficiently deoiled from an oil-impregnated scale generated at a steel mill or the like without causing thermal decomposition.

  As described above, according to the present invention, oil can be safely and efficiently deoiled from an oil-impregnated scale generated at a steel mill or the like without causing environmental problems, and the oil can be recovered from the oil-impregnated scale. And can be recycled.

  Therefore, the present invention has great industrial and environmental protection applicability.

It is a figure which shows the relationship between the steam saturation of dry steam, and the weight loss rate of an oil-containing scale. It is a figure which shows the relationship between the superheat temperature of dry steam, and the weight loss rate of an oil-containing scale. It is a figure which shows typically the deoiling mechanism in presence of dry steam. FIG. 4 is a diagram showing a deoiling mode in which the deoiling mechanism shown in FIG. 3 does not function even in the presence of dry steam. FIG. 4 is a diagram showing another deoiling mode in which the deoiling mechanism shown in FIG. 3 does not function even in the presence of dry steam. It is a figure which shows typically the deoiling mechanism in the airflow of dry steam. It is a figure which shows the one aspect | mode of the deoiling apparatus of this invention. It is a figure which shows the one aspect | mode of a deoiling processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scale surface 2 Oil particle 3 Water particle 4 Steam generator 5 Steam superheater 6 Deoiling processing device 7 Steam cooling device 8 Oil separation and recovery device 9 Screw 10 Filter 11 Steam inlet 12 Steam feed screw shaft 13 Scale inlet 14 Scale outlet 15 Oil-impregnated steam outlet

Claims (9)

  A method for deoiling an oil-impregnated scale, comprising bringing dry steam heated to a temperature below the temperature at which oil is thermally decomposed into contact with the oil-impregnated scale.   2. The oil-retaining scale deoiling method according to claim 1, wherein a temperature not higher than a temperature at which the oil is thermally decomposed is 220 ° C. or lower.   The method of deoiling an oil-containing scale according to claim 1 or 2, wherein a temperature not higher than a temperature at which the oil is thermally decomposed is a temperature of 100 ° C or higher.   The method for deoiling an oil-containing scale according to any one of claims 1 to 3, wherein the dry steam has a vapor saturation of 20 to 80%.   The oil-impregnated scale according to any one of claims 1 to 4, wherein the oil-impregnated scale is a scale having an oil content of 0.5% or more.   The method for deoiling an oil-containing scale according to any one of claims 1 to 5, wherein the air flow of the dry steam is brought into contact with the oil-containing scale. A deoiling device that performs deoiling by bringing dry steam superheated to a temperature below the temperature at which oil is thermally decomposed into contact with an oil-containing scale,
(A) a steam superheater that superheats dry steam to a temperature below the temperature at which oil is thermally decomposed; and
(B) a deoiling treatment apparatus for deoiling by introducing superheated dry steam from the steam superheater and bringing it into contact with the oil-impregnated scale;
An oil-retaining scale deoiling device comprising: The oil-retaining scale deoiling device according to claim 7, further comprising:
(C) an oil separation and recovery device that separates and recovers oil from the oil-containing steam derived from the deoiling treatment device;
An oil-retaining scale deoiling device comprising:   9. The oil-retaining scale deoiling device according to claim 7 or 8, wherein the oil-retaining scale is continuously fed to and discharged from the deoiling treatment device, and superheated dry steam is continuously introduced and led out from the steam superheating device. An oil-retaining scale deoiling device.

Images