JP2016217767A - Method for determining value of water-containing oil, method for recovering water-containing oil, and method for reusing water-containing oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for determining value of water-containing oil capable of determining value of water-containing oil in a simple manner, and to provide a recovering method, and a reusing method.SOLUTION: Conductivity of water-containing oil including water is measured. When the measured conductivity is equal to or less than a predetermined threshold value depending on required calorific value, it is determined that the water-containing oil is valuable.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a method for judging the value of a hydrous oil, a recovery method, and a reuse method.

  In the hot rolling process and cold rolling process of a steel mill, oil-containing wastewater containing oil such as rolling oil used in rolling is generated. The oil-containing wastewater is then purified by being treated in a water treatment process including stationary separation, pressure separation, activated sludge, and the like. For example, in Patent Document 1, when purifying oil-containing wastewater, after adding powdered carbide to the oil-containing wastewater and adsorbing oil or the like to the powdered carbide, the wastewater treatment method for pressure-flotation treatment of the oil-containing wastewater Is disclosed. According to the wastewater treatment method described in Patent Document 1, oil content and the like in oil-containing wastewater can be efficiently reduced.

  The oil separated from the oil-containing wastewater by the method described in Patent Document 1 becomes a water-containing oil containing moisture. Since this water-containing oil has a high water content and a low calorific value, it is necessary to further reduce the water content of the water-containing oil when the water-containing oil is reused as fuel. In this case, the water content of the hydrous oil can be reduced by adding a chemical to the hydrous oil and separating a part of the water in the hydrous oil, but the treated hydrous oil has a sufficient calorific value as a fuel. It was difficult to easily determine whether there is any value (presence or absence of value). For this reason, the hydrated oil is usually discarded because it is difficult to reuse it as fuel.

JP 2014-200700 A

  Therefore, the present invention has been made paying attention to the above-described problem, and is a method for judging the usefulness of hydrous oil, which can easily determine the usefulness of hydrous oil (whether there is sufficient calorific value). It aims to provide a collection method and a reuse method.

According to one aspect of the present invention, the electrical conductivity of the water-containing oil containing moisture is measured, and when the measured electrical conductivity is equal to or lower than a threshold value set in advance according to the required calorific value, Provided is a method for judging the value of water-containing oil, which is characterized by having a value.
According to one aspect of the present invention, a chemical is added to the first water-containing oil containing water contained in the oil-water separation tank, and at least a part of the water contained in the first water-containing oil and the first water-containing oil are added. A separation step of separating the second water-containing oil having a lower moisture content, and the water separated in the separation step and the second water-containing oil are sequentially discharged from the oil-water separation tank, and the water and the second water-containing oil are discharged. A recovery step of separately collecting the oil, and in the recovery step, the conductivity of the water discharged from the oil-water separation tank and the second water-containing oil are measured over time and measured. When the electrical conductivity is equal to or lower than a threshold value set in advance according to the required calorific value, it is determined that the second hydrous oil is valuable, and the oil-water separation tank is determined after it is determined that there is the potential. The second water-containing oil discharged from the tank is collected separately from the water. Method for recovering water oil and are provided.

  According to one aspect of the present invention, a chemical is added to the first water-containing oil containing water contained in the oil-water separation tank, and at least a part of the water contained in the first water-containing oil and the first water-containing oil are added. A separation step of separating the second water-containing oil having a lower moisture content, and the water separated in the separation step and the second water-containing oil are sequentially discharged from the oil-water separation tank, and the water and the second water-containing oil are discharged. A recovery step of separately collecting the oil and a reuse step of using the second hydrous oil recovered in the recovery step as fuel, and in the recovery step, the oil discharged from the oil-water separation tank The electrical conductivity of the water and the second hydrous oil is measured over time, and when the measured electrical conductivity is less than or equal to a threshold set in advance according to the required calorific value, the valuable second hydrous oil After judging that it is oil and having the above-mentioned value, Method of recycling water oil, characterized in that the second water oil discharged from the serial oil-water separator tank is collected separately and the water is provided.

  According to one aspect of the present invention, the value of water-containing oil can be easily determined.

It is a schematic diagram which shows the purification processing method of the oil-containing wastewater which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the total calorific value of a hydrous oil, and a moisture content. It is a graph which shows the relationship between the discharge time in a collection process, and the measurement result of electrical conductivity.

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
<Oil-containing wastewater purification method>
First, with reference to FIG. 1, the purification process method of the oil-containing waste water A which concerns on one Embodiment of this invention is demonstrated. In the rolling factory 1, processes such as hot rolling, cold rolling, washing, and plating are performed, and oil-containing wastewater A containing oil such as rolling oil and rust preventive oil is generated at this time.

  First, the oil-containing wastewater A generated in the rolling mill 1 is conveyed and accommodated in the receiving tank 2. The oil-containing wastewater A accommodated in the receiving tank 2 is allowed to stand in the receiving tank 2 so as to be separated into two phases of the first hydrous oil B1 and the water C. The first hydrous oil B <b> 1 is an oil component containing a large amount of moisture and is separated into the upper phase of the receiving tank 2. On the other hand, the water C is separated into the lower phase of the receiving tank 2. The first hydrous oil B1 separated in the receiving tank 2 is collected using a vacuum or the like and sent to the heating tank 3. After the first hydrous oil B1 in the receiving tank 2 is collected, the remaining water C is sent to the raw water tank 4.

Next, the first hydrous oil B <b> 1 accommodated in the heating tank 3 is heated until reaching a predetermined temperature, and then sent to the oil / water separation tank 5.
The first water-containing oil B1 accommodated in the oil / water separation tank 5 is added with a chemical such as a viscosity reducing agent or a flocculant that promotes the separation of the oil and water, and is stirred. Further, the first water-containing oil B1 is allowed to stand in the oil-water separation tank 5 for a predetermined time (for example, 2 to 3 hours), so that the second water-containing oil B2 having a lower water content than the first water-containing oil B1 and water Separate into two phases with C. At this time, the second hydrous oil B2 is separated into the upper phase of the oil / water separation tank 5, and the water C is separated into the lower phase of the oil / water separation tank 5 (separation step).

  Thereafter, the water C and the second water-containing oil B2 accommodated in the oil / water separation tank 5 are separately collected (recovery step). In the recovery step, the water C and the second hydrous oil B2 are discharged from the outlet provided at the bottom of the oil / water separation tank 5 and recovered. At this time, since water C exists in the lower phase in the oil / water separation tank 5, the water C is first discharged from the oil / water separation tank 5. The discharged water C is sent to the raw water tank 4. And if all the water C in the oil-water separation tank 5 is discharged | emitted, 2nd hydrous oil B2 will be discharged | emitted from the oil-water separation tank 5 next. The discharged second hydrous oil B2 is sent to the storage tank 6. Here, in the recovery step, the timing at which the second water-containing oil B2 is discharged from the oil-water separation tank 5 is determined using a method for determining the value of the water-containing oil described later. When it is determined that the second water-containing oil B2 has been discharged, only the second water-containing oil is discharged from the oil-water separation tank 5 thereafter, and the discharge path is from the path to the raw water tank 4 to the tank 6. Switch to the route to.

Next, the second hydrous oil stored in the tank 6 is used as a lower fuel such as cement fuel (reuse process). In the present embodiment, as will be described later, since the value of the second hydrous oil is judged in the recovery step (determination of whether or not it has a sufficient calorific value), the exothermic heat of the second hydrous oil after the recovery. There is no need to measure quantity.
On the other hand, the water C accommodated in the raw water tank 4 is purified by being subjected to general wastewater treatment such as pressure treatment and activated sludge treatment.

<Method for judging the value of hydrous oil>
Next, a method for judging the value of the hydrous oil according to the present embodiment will be described. In the present embodiment, the calorific value is determined as the value of the second hydrous oil in the above-described recovery step.
Here, FIG. 2 shows the relationship between the moisture content of various hydrous oils recovered from the receiving tank 2 and the oil / water separation tank 5 and the total calorific value. As shown in FIG. 2, the total calorific value of the hydrated oil has a substantially linear relationship with the moisture content. Further, the water-containing oil has a substantially linear relationship between the conductivity and the water content, and has a tendency that the conductivity decreases as the water content decreases. That is, the present inventor has found that the total calorific value of the hydrated oil can be indirectly measured by measuring the conductivity of the hydrated oil, and the value of the hydrated oil can be determined.

  Therefore, in the present embodiment, in the recovery process, a conductivity measuring device is provided on the outlet side of the bottom outlet of the oil / water separation tank 5 to measure the conductivity of the water C discharged from the outlet and the second hydrous oil B2. To do. At this time, the conductivity is measured continuously every predetermined time after the water C is discharged. Then, it is sequentially determined whether or not the measured conductivity is equal to or less than a threshold value set in advance according to the required amount of heat generation. As a result of the determination, when the conductivity is equal to or lower than the threshold value, it is determined that the discharged second water-containing oil B2 is valuable. Then, the second hydrous oil B <b> 2 discharged after that is discharged to the tank 6.

  In the recovery step, water C is discharged when the conductivity exceeds the threshold even after a predetermined time after water C is completely discharged after the water C is discharged from the oil / water separation tank 5 first. The second water-containing oil is determined not to be valuable and is sent to the heating tank 3. And about a 2nd hydrous oil determined not to be valuable, a series of processes after a heating and a separation process may be performed again.

  In FIG. 3, an example of the measurement result of the electrical conductivity in a collection process is shown. In the example shown in FIG. 3, the conductivity of water C and second oil-containing water B2 discharged from the discharge port of the oil / water separation tank 5 was measured at intervals of 5 minutes. Further, the calorific value necessary for the lower fuel was set to 4000 kcal / kg or more, and the necessary moisture content was set to 55% by mass or less from the relationship of FIG. And since the electric conductivity corresponding to the moisture content 55 mass% used as an upper limit was 25 mS / s, the value of this electric conductivity was made into the threshold value. As a result of measuring the electrical conductivity, the electrical conductivity became 25 mS / s or less at the timing when 45 minutes had elapsed from the time of discharging, and it was confirmed that the second hydrous oil discharged thereafter has value.

<Modification>
Although the present invention has been described above with reference to specific embodiments, it is not intended that the present invention be limited by these descriptions. From the description of the invention, other embodiments of the invention will be apparent to persons skilled in the art, along with various variations of the disclosed embodiments. Therefore, it is to be understood that the claims encompass these modifications and embodiments that fall within the scope and spirit of the present invention.

For example, in the above embodiment, the value of the second water-containing oil discharged from the oil / water separation tank 5 is determined, but the present invention is not limited to such an example. For example, the value of the hydrated oil separated and recovered from water may be determined by measuring the conductivity. In this case, the method for separating oil and water and the method for collecting hydrous oil are not limited to the above-described embodiment.
Moreover, in the said embodiment, although the required calorific value was 4000 kcal / kg and the threshold value was 25 mS / m from the moisture content 55 mass% corresponding to this, this invention is not limited to this example. The necessary calorific value, moisture content, and electrical conductivity threshold are appropriately set in accordance with the components of oil contained, the impurities contained in water, and the type of fuel used. For example, when the hydrous oil is separated from the oily drainage discharged from equipment such as a rolling mill, the threshold value is set to any value in the range of 1 mS / m to 25 mS / m depending on the components of the hydrous oil. Thus, the hydrous oil can be used as a general lower fuel.

<Effect of embodiment>
(1) The method for judging the value of a hydrous oil according to one aspect of the present invention is a method in which the conductivity of a hydrous oil containing moisture is measured, and the measured conductivity is a threshold value set in advance according to the required calorific value. In the following cases, it is judged that the hydrous oil is valuable.
According to the above-described configuration, the value that is a necessary calorific value can be determined simply by measuring the conductivity of the hydrous oil, and therefore the value can be easily determined.

(2) In the configuration of (1) above, the hydrous oil is separated and recovered from the oil-containing wastewater, and the threshold is set to any value between 1 mS / m and 25 mS / m.
According to the above configuration, it is possible to easily determine the value of the hydrous oil having a low calorific value separated from the oil-containing wastewater generated in a rolling mill or the like. In addition, compared to other methods for determining the value by burning the hydrated oil, the cost for determining the value can be reduced, so when selling the hydrated oil as an inexpensive lower fuel Even profitability can be ensured.

  (3) In the method for recovering the hydrous oil according to one aspect of the present invention, the chemical is added to the first hydrous oil B1 containing the water contained in the oil / water separation tank 5, and the water content of the first hydrous oil B1 is increased. A separation step of separating at least a portion of the second water-containing oil B2 having a lower water content than the first water-containing oil B1, and the water C and the second water-containing oil B2 separated in the separation step in order from the oil-water separation tank 5 A recovery step for discharging and separately collecting the water C and the second hydrous oil B2, and in the recovery step, the conductivity of the water C and the second hydrous oil B2 discharged from the oil / water separation tank 5 is passed on. When the measured conductivity is less than or equal to a preset threshold value according to the required calorific value, it is determined that the second water-containing oil B2 is valuable and is determined to be valuable. After that, the second hydrous oil B2 discharged from the oil / water separation tank 5 is recovered separately from the water.

  According to the above configuration, it is possible to easily determine the value of the second hydrous oil as in the configuration (1). In addition, the first water-containing oil B1 having a high water content and a low value can be further separated into oil and water, so that the generation of a low-value water-containing oil that cannot be reused and discarded can be suppressed. Industrial waste processing costs can be reduced. Furthermore, since the recovered second oil-containing water B2 is valuable, it can be reused or sold as fuel. In addition, by measuring the conductivity at the time of recovery, for example, the switching timing can be detected more accurately than when the switching between the discharged water C and the second hydrous oil B2 is visually determined from the appearance. be able to.

(4) In the configuration of (3) above, when the second hydrous oil recovered in the recovery process is not valuable, the recovered second hydrous oil is processed again in the separation process.
According to the said structure, generation | occurrence | production of a hydrous oil with low value can further be suppressed with respect to the structure of (3).

(5) In the method for reusing water-containing oil according to one aspect of the present invention, the chemical is added to the first water-containing oil B1 containing water contained in the oil-water separation tank 5, and the water contained in the first water-containing oil B A separation step of separating at least a part of the second water-containing oil B2 having a lower water content than the first water-containing oil B1, and the water separated in the separation step and the second water-containing oil B2 in order from the oil-water separation tank 5 A recovery step of discharging and collecting the water C and the second hydrous oil B2 separately, and a reuse step of using the second hydrous oil B2 recovered in the recovery step as a fuel. When the conductivity of the water C and the second hydrous oil B2 discharged from the separation tank 5 is measured over time, and the measured conductivity is less than or equal to a threshold value set in advance according to the required calorific value, After judging that it is the second water-containing oil B2 The second water-containing oil B2 discharged from the water separation tank 5 is collected separately from the water C.
According to the said structure, the effect similar to the structure of said (3) can be acquired.

DESCRIPTION OF SYMBOLS 1 Rolling factory 2 Receiving tank 3 Heating tank 4 Raw water tank 5 Oil-water separation tank 6 Tank A Oil-containing drainage B1 1st hydrous oil B2 2nd hydrous oil C Water

Claims (5)

Measure the conductivity of water-containing hydrous oil,
A method for judging the value of a hydrous oil, wherein the hydrous oil is judged to be valuable when the measured conductivity is equal to or less than a threshold value set in advance according to a required calorific value. The water-containing oil is separated and recovered from the oil-containing wastewater,
The method for judging the value of hydrous oil according to claim 1, wherein the threshold value is set to any value between 1 mS / m and 25 mS / m. The chemical | medical agent is added to the 1st water-containing oil containing the water accommodated in the oil-water separation tank, The 2nd water content whose moisture content is lower than the said 1st water-containing oil and at least one part of the said water contained in the said 1st water-containing oil A separation step of separating the oil;
The water separated in the separation step and the second water-containing oil are sequentially discharged from the oil-water separation tank, and the water and the second water-containing oil are separately collected and recovered.
In the recovery step, the conductivity of the water discharged from the oil / water separation tank and the second water-containing oil are measured over time, and the measured conductivity is preset according to the required calorific value. When it is less than or equal to the threshold value, it is determined that the second hydrous oil is valuable, and the second hydrous oil discharged from the oil / water separation tank after it is determined that the oil is valuable is separated from the water. A method for recovering hydrous oil, characterized by recovering.   The hydrated oil according to claim 3, wherein when the second hydrated oil recovered in the recovery step is not valuable, the recovered second hydrated oil is treated again in the separation step. Recovery method. The chemical | medical agent is added to the 1st water-containing oil containing the water accommodated in the oil-water separation tank, The 2nd water content whose moisture content is lower than the said 1st water-containing oil and at least one part of the said water contained in the said 1st water-containing oil A separation step of separating the oil;
A recovery step of sequentially discharging the water separated in the separation step and the second water-containing oil from the oil-water separation tank and collecting the water and the second water-containing oil separately;
A reuse step of using the second hydrous oil recovered in the recovery step as a fuel,
In the recovery step, the conductivity of the water discharged from the oil / water separation tank and the second water-containing oil are measured over time, and the measured conductivity is preset according to the required calorific value. When it is less than or equal to the threshold value, it is determined that the second hydrous oil is valuable, and the second hydrous oil discharged from the oil / water separation tank after it is determined that the oil is valuable is separated from the water. A method for reusing water-containing oil characterized by collecting.

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