JPS621639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic desalination apparatus, and more particularly to an electrostatic desalination apparatus suitable for purifying fuel oil supplied to a furnace such as a gas turbine.

Generally, in gas turbines, the temperature of combustion gas is high, so high-temperature corrosion may occur near the exhaust turbine. This is because the vanadium compounds in the fuel oil are combusted into low melting point compounds such as vanadium pentoxide, and these compounds adhere to turbine blades and the like in a molten state, causing corrosion. Moreover, this high-temperature corrosion is accelerated when alkali metals such as sodium and potassium are contained in the fuel. For this reason, fuel oil is pretreated to remove impurities such as sodium and potassium, which are factors that promote corrosion.

Conventionally, electrostatic demineralization equipment has been used for pretreatment of fuel oil. This conventional electrostatic desalination equipment is called a water washing method, and is disclosed in Japanese Patent Publication No. 50-36310,
Special Publication No. 50-36505 or U.S. Patent No. 3839176
This is a method of washing fuel oil with water, as disclosed in No. That is, as shown in FIG. 1, washing water 3 is injected into the fuel oil 1 in an amount of about 5 to 10% by weight based on the fuel oil 1 before the electrostatic demineralization tank 2, and the oil and water are mixed in the oil-water mixer 4. Mix. The oil 5 mixed with this water is led to the electrostatic demineralization tank 2, and in the electrostatic field in the electrostatic demineralization tank 2, the water droplets containing sodium, potassium, etc. present in the fuel oil are brought into contact and coalesced. This process is repeated to grow water droplets and oil to a particle size that allows them to be separated by gravity sedimentation, thereby separating the oil and water and desalting the fuel oil. Since the separated waste water 6 contains oil, a waste water treatment device 7 for removing oil is provided. The desalinated fuel oil 8 is supplied to a furnace (not shown).

However, in the above conventional electrostatic desalination equipment,
Separation of impurities in oil relies on gravity settling of water droplets containing impurities, so the separation speed is slow;
Moreover, since the settling of water droplets in the electrostatic demineralization tank 2 is resisted by the flow of the water-mixed oil 5, a delay in separation speed is promoted, resulting in a problem of poor demineralization performance. Further, in the conventional device, it is necessary to provide the oil/water mixer 4 and to separately provide an expensive wastewater treatment device 7, which has the drawback of increasing the size of the device.

The present invention has focused on the above-mentioned conventional problems, and in desalination of fuel oil, in particular, effectively removes emulsions and impurities such as sodium and potassium from oil without mixing washing water. Let it show,
It is an object of the present invention to provide an electrostatic desalination device that can improve desalination performance.

In order to achieve the above object, an electrostatic desalination apparatus according to the present invention is an apparatus equipped with a high voltage electrode and a ground electrode for forming an electric field in an electrostatic desalination tank, in which both electrodes for forming an electric field are connected to each other. An electrostatic desalination device is constructed by equipping an upstream electrode with a discharge electrode and a ground electrode opposite the electrode, and discharges fuel oil, etc. into the oil in advance to charge impurities in the oil, and then deionizes it in an electric field. It is possible to obtain good desalting performance by effectively utilizing the Coulombic force of charged impurities.

The principle of the electrostatic desalination apparatus according to the present invention is as follows. That is, the acting force when collecting and removing the emulsion in oil and impurities in an electrostatic field as in the conventional device is expressed by the following equation.

F ₁ = D _P ³ /4・ε−1/ε+2・K・E ² ...(1) Here, F ₁ is the force exerted on the emulsion in oil and impurities in oil, and D _P is the force exerted on the emulsion in oil and the impurities in oil. The particle diameter of the impurity in the oil, ε is the dielectric constant of the emulsion in oil and the impurity in the oil, K is the proportionality constant, and E is the electric field strength.

In this way, the acting force F ₁ of an emulsion, impurity, or particle in an electrostatic field is 2 of the electric field strength E.
It is proportional to the third power of the particle diameter D _P. Therefore, in order to increase the acting force F ₁ , either the particle diameter D _P must be increased or the electric field strength E must be increased. Since the particle diameter D _P varies depending on the oil to be treated, a method is generally adopted in which the electric field strength E is increased. However, in this method, the maximum electric field strength E that can be applied is determined depending on the oil to be treated, so there is a limit to how much the electric field strength E can be increased.

As a solution to this problem, the inventors created a partial discharge in oil to give an electric charge to the emulsion in oil and impurities. The force exerted on the particles due to this charging is expressed by the following equation.

F ₂ =q・E+D _P ³ /4・ε−1/ε+2・K・E ²
...(2) Here, q is the amount of charge of the emulsion in oil and the impurities in oil.

As can be understood from equation (2), the acting force F ₂ is the sum of the dielectric acting force F ₁ in equation (1) and the Coulomb force q・E associated with the electric charge, and even at the same electric field strength E, The force exerted on the emulsion and impurities is increased, making it possible to effectively remove them.

Embodiments of the present invention applying this principle will be described in detail with reference to the drawings.

FIG. 2 shows an electrostatic desalination apparatus according to this embodiment.
This device is equipped with an electrostatic demineralization tank 10 as a grounded oil tank. An oil supply pipe 12 for supplying the oil to be treated to the desalination tank 10 is connected to the upper end of the desalination tank 10, and an extraction pipe 14 for drawing out the treated clean oil is connected to the lower end. is connected and the oil is sent to desalination tank 1.
The flow is made to flow from above to below within 0.

A discharge electrode 20 connected to a high-voltage power source 18 provided outside the desalination tank 10 is disposed at the center of the opening 16 of the oil supply pipe 12, which is the joint between the desalination tank 10 and the oil supply pipe 12. ing. This discharge pole 20
is connected to an external conducting wire 24 via an insulator 22 so as not to be electrically connected to the oil supply pipe 12. In addition, a discharge electrode 20 is provided in the desalination tank 10 in the open opening 16.
A ground electrode 26 is extended to face the tip of the discharge electrode 20 in close proximity, and forms a charging section 28 together with the discharge electrode 20 . Therefore, by applying a high voltage to the discharge electrode 20 when the oil to be treated flows into the desalting tank 10, a partial discharge in the oil is generated between the discharge electrode 20 and the ground electrode 26.

On the downstream side of the charging section 28, the desalination tank 1
A distribution layer 30 filled with oil-insoluble glass beads, beads made of synthetic resin such as plastic, and conductive beads made of iron, aluminum, etc. is disposed on the top of 0. The distribution layer 30 is provided over the entire cross section of the demineralization tank 10 so as to divide the demineralization tank 10 into upper and lower sections, and uniformly disperses and rectifies the oil supplied from the oil supply pipe 12.

The downstream side of such a distribution layer 30 is provided with an aggregation section 36 in which a large number of flat high voltage electrodes 32 and ground electrodes 34 are alternately arranged in an upright manner. That is, the high-voltage electrodes 32 are spaced apart from each other in the middle of the ground electrodes 34 that are arranged in parallel at predetermined intervals, and only the high-voltage electrodes 32 are electrically connected to each other to connect to the external high-voltage power source 18. On the other hand, the ground electrodes 34 are respectively connected to the desalination tank 10. Therefore, by applying a high voltage to the high voltage electrode 32, an electric field is formed between the two electrodes 32 and 34.

A high voltage electrode 3 is located further downstream of the aggregation section 36.
An impurity extraction section 40 forming a clean oil outlet 38 directly below the demineralization tank 2 is provided to divide the desalination tank 10 into upper and lower sections. This impurity extraction part 40 is a desalination tank 10
It communicates with an outlet 42 formed in the side wall of the tank, so that the extracted impurities can be discharged to the outside. Moreover, the clean oil outlet 38 is formed to penetrate the extraction part 40 so that the treated oil flows down to the lower part of the desalination tank 10. A charge collection section 44 having a conductive filler is formed in the extraction pipe 14 provided at the lower end of the desalination tank 10, and after collecting the charge remaining in the treated oil, the cleaning It is assumed that the oil is led out of the device from the extraction pipe 14 as oil.

The action of removing impurities such as emulsion, sodium, and potassium from the oil to be treated using such an electrostatic desalting device is performed as follows.

When the oil to be treated is supplied from the oil supply pipe 12, a partial discharge in the oil is applied to the oil to be treated by the charging section 28 of the opening 16 in advance. This discharge causes the emulsion-in-oil and impurities to become electrically charged.
The oil containing the emulsion and non-gun materials charged in the charging section 28 is rectified in the distribution layer 30 and then introduced into the aggregation section 36 . This aggregation part 36
Since an electric field is generated between the high voltage electrode 32 and the ground electrode 34, the emulsion and impurities are
It is quickly collected in the vicinity of the electrode surface of the ground electrode 34 by the acting force in equation (2), that is, the acting force that is the sum of the acting force in the electrostatic field and the acting force due to the Coulomb force. The impurities collected near the ground electrode 34 form a thin plate-shaped lump on the electrode surface, descend with the flow of the treated oil, and are collected in the impurity extractor 40 provided at the bottom of the ground electrode 34, forming a lump of impurities. It is discharged to the outside from the outlet 42 as a liquid. on the other hand,
The clean oil from which emulsion and impurities have been removed is collected near the high-voltage electrode 32, flows down from the outlet 38 to the lower part of the demineralization tank 10, and after the flowing charge of the clean oil is removed by the charge collection section 44, taken out of the device.

In this way, according to this example, oil can be directly desalted without mixing water,
There is no need to install an oil-water mixer or the like, and there is no need to install an expensive wastewater treatment device to separate water from the impurities and emulsion removed after treatment. Therefore, it is possible to downsize the desalination apparatus. Further, the charging section 28 can be installed very easily, and impurities can be removed very effectively by simply installing it before the aggregating section 36 and discharging it into the oil in advance. .
Furthermore, since the removal process coincides with the oil flow direction, the acting force is not resisted by the oil flow.

FIG. 3 shows another embodiment of the electrostatic desalination apparatus. In this embodiment, the charging section 28 is installed on the downstream side of the distribution layer 30 and immediately before the condensing section 36, and the ground electrode 26, which is to be disposed opposite to the discharge electrode 20, is placed in the condensing section 36.
This is also used as the ground electrode 34 of No. 6.
The other configurations are the same as those in the previous embodiment, so the same numbers are given and explanations are omitted.

According to this embodiment, since the emulsion and impurities in the oil are introduced into the aggregation section 36 immediately after being charged, there is no charge leakage and the charge is effectively utilized.

As described above, according to the electrostatic desalination apparatus of the present invention, since the emulsion and impurities such as sodium and potassium in the oil are charged in advance, the action force for separating them from the oil in the agglomeration section increases, making it extremely efficient. It has the effect of being able to remove it in a targeted and effective manner.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional electrostatic desalination apparatus, FIG. 2 is a block diagram of an electrostatic desalination apparatus according to an embodiment of the present invention,
FIG. 3 shows a configuration diagram of another embodiment. 10... Electrostatic demineralization tank, 12... Oil supply pipe, 14...
... extraction tube, 20 ... discharge electrode, 26, 34 ... ground electrode, 28 ... charging section, 32 ... high voltage electrode,
36...Agglutination part.

Claims (1)

[Claims] 1. In an electrostatic desalination device that is equipped with a high voltage electrode and a ground electrode in a flow path and removes impurities in the oil by passing oil through an electric field formed by the electrode, the high voltage electrode that forms the electric field and the ground electrode An electrostatic desalination device comprising a charging section comprising a discharge electrode and a ground electrode provided opposite to the discharge electrode at a position upstream of the electrode.