KR100226331B1 - Waste Oil Disposal Method using Electrolysis and Heating Energy - Google Patents

Abstract

In the method of treating industrial wastewater by electrolysis, the wastewater treatment efficiency can be improved by applying heat energy by heating the electrolytic cell using waste steam or steam or directly introducing waste steam or steam into the electrolytic cell during the electrolytic treatment. By the combined treatment of the electrolysis and thermal energy of the present invention, the oil removal efficiency of waste oil such as cutting oil, which has not been sufficiently treated in the prior art, can be remarkably improved.

Description

Waste Oil Disposal Method using Electrolysis and Heating Energy}

TECHNICAL FIELD The present invention relates to a method for treating industrial wastewater, and more particularly, to an improved method for treating various wastewater, such as cutting oil and abrasive waste oil, by using electrolysis and thermal energy.

In general, the wastewater treatment method includes a treatment method using a hormonal drug, a biological treatment method using a microorganism, a physical treatment method by electrolysis and electrooxidation, and a combination thereof.

Physical and chemical treatment methods include oxidizing agents, adsorption by activated carbon, electrodialysis, ion exchange, and the like. The method of using an oxidant has the advantage that the oxidant reacts well with the organic matter in the wastewater and does not generate secondary impurities, but it is expensive in terms of cost and maintenance costs of the treatment equipment, so it is widely used except for special purpose wastewater treatment. It is not. In addition, while the adsorption treatment method using activated carbon also has a good odor removal effect, the activated carbon itself is expensive and has a troublesome use of regeneration treatment after a certain period of time. In addition, electrodialysis or ion exchange is disadvantageous in that it is not suitable for treating a large amount of wastewater.

The conventional electrolysis method has a large amount of sludge after treatment, which increases the post-treatment cost for sludge treatment, and enables a small capacity treatment. A large amount of treatment costs a lot of facility costs and a deterioration in processing capacity. There was something lovely.

On the other hand, cutting oils and grinding waste oils based on mineral oils and vegetable oils are chemical substances that are physically applied to emulsify oils to prevent heat generation and damage to processing tools. It is classified as waste and processed by pyrolysis incinerator. Waste oil treatment methods such as cutting oil and abrasive waste are generally required to incinerate waste oil. However, this has a problem of generating soot due to incineration and increasing energy consumption for incineration.

Therefore, the main object of the present invention is to solve the disadvantages of the conventional wastewater treatment method, in particular cutting oil, abrasive waste oil and the like, while providing an improved treatment method with improved oil removal ability.

The present inventors have found that the oil removal efficiency of the waste oil can be greatly improved by using a method of applying thermal energy using steam or waste steam to the wastewater treatment method by electrolysis.

1 is a waste oil treatment process diagram according to the present invention.

Pollutants contained in waste water have inherent charge and activation energy. When the pollutant is to be treated by the electrolytic method, the pollutant becomes unstable by electrostatic repulsive force and requires energy according to the material to be removed to the floc.

The inventors have found that the decomposition efficiency of contaminants can be increased when generating a proper amount of heat during the electrolytic treatment in the conventional electrolytic method. In the electrolytic method, since a power source is used, heat energy is generated by the electrode after a certain time, but this heat energy alone is insufficient to significantly improve the wastewater treatment efficiency. Each pollutant has its own activation energy, and when more energy is applied, it becomes unstable and coagulates or breaks down. In addition to the electrolytic method, the present inventors apply waste heat of waste steam or steam to the inside or outside of the electrolytic cell to raise the temperature of the waste water or waste oil to be treated, and thus the treatment efficiency is remarkably increased. It has been found that improvements have been made to complete the present invention. The method of applying heat energy is to wrap the steam tube outside the electrolytic cell and circulate steam or waste steam into the tube to heat the electrolytic cell, or to directly inject the steam or waste steam into the electrolytic cell for cold waste water (16-20 ℃). Heat). The heating temperature is 60 to 120 ° C, operating to reach the appropriate temperature according to the target wastewater.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Waste Cutting Oil and Polishing Waste Oil Treatment Method (Oil Removal) Using mineral oil and vegetable oil as raw materials When electrolytic treatment of waste oil such as waste cutting oil and abrasive waste oil is performed in an electrolytic cell, it is separated into emulsified oil (colloid) and water. Colloidal materials in water have a constant high charge of + or-when charged, and this emulsified oil becomes unstable as H ⁺ or OH ^- in the electrode forms an electric double layer by an electrostatic bond, which causes an electrostatic repulsion. By flocculation.

In general, waste cutting oil and used abrasive oil are decayed after a certain time of use, resulting in an alkaline pH of 10 or more. In the present invention, in order to neutralize the pH of the waste oil in order to increase the density of the charge, neutralizing treatment is performed to add pH 6-7 by adding an appropriate amount of limestone, caustic soda, alumina sulfate and the like. The emulsified oil has an inherent charge, so when an electric charge is applied, the emulsified oil becomes unstable due to electrostatic repulsion, and a floc is formed, and when a polymer flocculant is added, it becomes a large floc and separates from water. At this time, heat energy of 60 ° C. or higher is added to promote separation of the emulsified oil and water.

In the electrolytic process, water reacts at the anode and cathode as follows:

Cathode ^{_{reaction: 2H 2 O + 2e - ---}} → 2H + + 2OH -

^{2H + + 2e - --- → H} 2

Anode ^{_{reaction: H 2 O + 2e - ---}} → 1/20 2 + 2H +

As shown in Figure 2, the waste oil treatment process of the present invention

First, the target wastewater is connected to the storage tank 1, collected, and the screen tank 2 first filters the waste and the like by the screen filter. Depending on the acidity of the waste oil filtered in this way, the neutralizing tank 10 is neutralized with neutralizing agents such as caustic soda, limestone, and peninsula sulfate to pH 6-7.

Subsequently, wastewater is sent to the primary electrolytic treatment tank 3, which is a key aspect of the present invention, for electrolysis treatment, while the electrolytic treatment tank 3 is heated or electrolyzed using waste steam and steam. Steam or waste steam is added directly to the tank (3) and heat-treated to 80 degreeC or more. The treatment zone of the primary electrolytic treatment tank 3 used DC 12V and 15A as the power supply, SUS304 was used as the electrode plate, and the treatment time was 5 minutes to 10 minutes. Oil was observed to be removed. Send the first electrolytic wastewater to the primary settling tank (4) to settle and float flocs to dispose of the deposited residue, and send the secondary electrolyzer (5) to electrolytic and heat treatment under the same conditions as the primary electrolyzer (3). To separate the remaining 20% of the oil. The wastewater treated in the secondary electrolyzer (5) is sent to the secondary sedimentation tank (6) to dispose of the sediment, which is then filtered through the activated carbon filter tower or SAND filter in the filter tank (7) and discharged.

The following example shows the results of treatment analysis of cutting oil treated according to the method of the present invention.

Example 1

Waste Cutting Oil Treatment Test

The cutting oil generated in the machining was randomly collected, the waste oil was treated by the electrolysis and thermal energy combination method of the present invention, and the oil removal efficiency thereof was measured and shown in Table 1 below.

Table 1: Deoiling Assay

Sample No. Before treatment (mg / ℓ) After treatment (mg / l) Processing efficiency (%) One 66000 3 99.99 2 66000 3 99.99 3 82000 3 99.99 4 82000 3 99.99 5 75000 3 99.99 6 76000 3 99.99

From Table 1 it can be seen that the oil removal efficiency reaches 99.99%, the treatment efficiency of the waste oil treatment method according to the present invention is extremely excellent.

Industrial wastewater treatment method using the electrolytic method and indirect thermal energy of the present invention is to significantly improve the oil removal efficiency of the waste oil, which was unsatisfactory in the prior art, the operation time is shorter than the conventional method, and the conventional electrolytic method It is possible to carry out additional heat energy supply equipment, so operating cost is low and it is economically effective because it is suitable for substitute treatment.

Claims (3)

In the industrial wastewater treatment method by electrolysis, Step to neutralize the cutting oil or abrasive waste oil to pH 6-7 by adding cutting oil or abrasive waste oil to limestone, caustic soda, or alumina sulfate: A first electrolysis step in which the neutralized waste oil is electrolyzed while applying electrothermal energy by heating the electrolytic cell using waste steam or steam or by directly introducing waste steam or steam into the electrolytic cell; A first precipitation step of disposing the electrolyzed waste oil and then depositing the sediment; A second electrolysis step of electrolyzing the waste oil floating in the first precipitation in the same manner as the first electrolysis step; A process for treating cutting oil or abrasive waste oil, characterized by performing a secondary settling step of precipitating secondary electrolyzed waste oil to dispose of debris and discharging the floated water. The method of claim 1, Cutting oil or abrasive waste oil treatment method using the electrolytic and thermal energy, characterized in that it further comprises a filtration step of passing the water passed through the secondary precipitation step through the activated carbon filter tower or sand filter (SAND) filter to discharge the excess water. . The method of claim 1, wherein the first and second electrolysis steps, By heating the electrolytic treatment tank by waste steam or steam or directly injecting the waste steam or steam, the temperature of the waste water is 60-120 ° C. according to the type of waste water, and the input waste water is discharged from the electrolytic treatment tank. Cutting oil or abrasive waste oil treatment method using electrolysis and thermal energy, characterized in that the discharge by electrolytic treatment for 5-10 minutes depending on the type of oil.

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