JPS6081289A - Electrostatic desalination unit - Google Patents

Abstract

PURPOSE:To provide the titled unit in which both grid high-voltage and gutter- shaped grid ground electrodes are set with inclination and designed for the water droplets condensed between these electrodes to flow down the gutter-shaped electrode to avoid mutual contact of the droplets with the ascending oil, also prevent said oil from being accompanied by the salts contaminated in the original oil to be treated. CONSTITUTION:Oil to be treated is introduced through pipe 2 into tank 1 and distributed by pipe 3, moving within the tank, in the form of ascending flow. The impurities in said oil are repeatedly aggregated into gross particles within the alternate current electric field formed through lower stage ground electrode 22a and lower stage high-voltage electrode 21a; said particles descending in the direction of gravitational force to the bottom of the tank 1, are drawn out through outlet 10, whereas the treated oil reachs the electric field zone formed through upper ground electrode 22b and upper high-voltage electrode 21b, the residual impurities being aggregated into gross particles are separated from the oil to be treated, being drawn out through the outlet 10. EFFECT:Resulting in marked reduction in the salt content in the final oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic desalination device that completely removes impurities (water and other impurities) by using a separation effect based on electrostatic force.

Generally, when desalting salts such as sodium and potassium contained in natural crude oil or synthetic crude oil, and when dehydrating water, water is injected in advance and separated by static electricity. A conventional electrostatic desalination apparatus will be explained based on FIGS. 1 and 2.

In this device, an oil to be treated introduction pipe 2 is attached to the lower part of an electrostatic desalination willow 1 and connected to a distribution pipe 3 in the tank, and a ground electrode 4 and a high voltage electrode 5 are arranged in the tank. Oil collection pipe 6 at the top of the tank
are placed.

In the figure, 7 is a transformer, 8 is an insulator, and 9 is an interface meter.

10 is a drain port, and 11 is an insulating bushing.

This device performs electrostatic desalination as follows.

First, the oil to be treated is heated to a temperature of approximately 70 degrees or higher using a heat exchanger, and then several parts of cleaning water are mixed in to create an appropriate pressure difference (approximately i
km) through a mixing valve to mix the oil and water. Next, the treated oil mixed with water is uniformly introduced into the electrostatic demineralization tank 1 from the distribution pipe 3 via the treated oil introduction pipe 2. In the electrostatic demineralization tank 1, a high voltage is applied between a ground electrode 4 and a high voltage electrode 5 to form an electric field. The microscopic water droplets mixed in the oil repeatedly coalesce with each other in this electric field, increase in particle size, and settle due to gravity. Furthermore, sodium in oil,
Potassium is dissolved into minute water droplets mixed in the oil and partially separated from the oil, and these minute water droplets coalesce repeatedly in this electric field, increasing in particle size and settling by gravity.

However, in this device, the rising oil and the settled water droplets come into contact and re-entrain the salts that were once separated into the wash water. This increases the concentration of salts in the oil to be treated, which has to be treated again in an electric field, and also has the disadvantage that oil is mixed into the cleaning water, making it necessary to reprocess it.

Furthermore, water droplets that have become smaller due to repeated coalescence in an electric field will settle only when they have grown to a certain particle size, which has the disadvantage that it takes a considerable amount of time to separate the water droplets.

The present invention has been made to eliminate all of these drawbacks, and its purpose is to provide an electrostatic desalination device that can effectively remove impurities by effectively performing a separation action using electrostatic force. It is something.

That is, the present invention includes a grid high voltage electrode in an electrostatic demineralization tank,
This electrode and a pair of lattice-shaped ground electrodes are arranged at an angle, and the water droplets that condense between the pair of electrodes are allowed to flow down into the lattice-shaped ground electrode, thereby controlling the flow of oil to be treated rising from the bottom. In addition, the oil to be treated is discharged from the oil collection pipe by forming a flow path in the opposite direction to the water droplets that settle between the two electrodes, similar to conventional electrostatic desalination equipment. It is.

The present invention will be described below based on illustrated embodiments. FIG. 3 is a schematic cross-sectional view of the electrostatic desalination apparatus, FIG. 4 is a schematic longitudinal cross-sectional view thereof, and FIG. 5 is a cross-sectional view taken along line M-7 in FIG. 4. This electrostatic desalination apparatus has lower and upper lattice high voltage electrodes 21a, 21b arranged in an electrostatic desalination tank 1, and cypress ground electrodes 22a, 22b opposed thereto. Each electrode 2'
As shown in FIG. 4, the poles 1a, 21b, 22a, and 22b are arranged in a sloping roof-like manner with a high central portion and a low elevation 1, and among these, the grounding poles 22a and 22b are trough-shaped. It is formed.

Although the ground electrodes 22a and 22b illustrated here have a cylindrical half-shape, they may have other shapes in order to disturb the electric field. Further, the ground electrodes 22a and 22b may be placed at the positions indicated by the broken lines depending on whether the oil flow is made uniform or uneven.

Here, in the present invention, the high voltage electrode and the ground electrode are 2
The number of pairs is not limited to one, and one pair or three or more pairs may be used depending on the processing performance. Although the shape of the grid is not particularly limited, it is necessary that the ground electrode be located directly below the single high-voltage electrode where the water droplets grow the most.

In addition, the distance between the ground type @ 22a at the bottom end and the separated water surface may be an appropriate value, but the distance between the pair of high voltage electrodes 2 placed at the bottom end
It is desirable to increase the distance between 1a and the ground electrode 22a. That is, during electrostatic desalination, impurities present in the electrostatic field cause dielectric polarization, which moves to form a current. For this reason, direct movement of charge from the high-voltage electrode to the ground electrode, which is the opposing electrode, as in spark discharge, does not involve the movement of impurities as charge carriers, and is therefore undesirable as it wastes power. In a spark discharge, for example, in a uniform electric field, the threshold value is the spark initiation electric field strength obtained by dividing the applied voltage by the distance between the two poles. For this reason, the applied voltage is normally set to the maximum value that does not cause spark discharge between the two electrodes in order to maintain a high salt removal rate. At this time, the applied voltage varies depending on the moisture content in the oil to be treated, but usually], c
It is about 1 to 10 kV per m.

Note that the same members and devices in the figure as those in FIG. 1 are given the same numbers, and their explanations will be omitted.

However, the lever device removes impurities from the oil to be treated in the following manner.

The oil to be treated is introduced through the inlet pipe 2 and distributed through the distribution pipe 3. When this oil to be treated becomes an upward flow and passes through the tank and reaches the AC electric field formed by the lower ground electrode 22a and the lower high voltage electrode 21a, the impurities contained in the oil to be treated repeatedly coalesce. Then, they become large particles that fall in the gravity direction (opposite direction to the flow of the oil to be treated), separate from the oil to be treated, reach the water layer at the bottom of the electrostatic demineralization tank 1, and flow through the drain port 10. being extracted.

On the other hand, the treated oil is applied to the upper ground electrode 22b and the upper high voltage electrode 2.
Upon reaching the alternating current electric field formed by 1b, the impurities that were not removed in the lower stage 1L field coalesce again and again, becoming large particles that fall, and are separated and removed from the oil to be treated.
Ground electrode 22a.

22b flows down into the groove shape, reaches the inner circumference of the electrostatic demineralization tank 1, reaches the lower water layer, and the lowermost electrode 21a
, 22a together with the separated water is extracted from the drain 10.

According to this device, the ground electrode 22a is in the shape of a trough.

Since the enlarged water droplets settle in 22b, the settling distance of the water droplets is short and the processing time can be reduced, and the rising oil does not come into contact with the settled water droplets, so that the salts that have been separated into the washing water are reused. Not entrained in oil.

Next, a specific example of electrostatic desalination using this apparatus will be described.

Oil to be treated (temperature 120°C 1M viscosity 7 C8T.

As a result of desalting the oil (with a salt content of 300 ppm) using the apparatus shown in Figure 3, the salt content in the oil after treatment was 20 ppm or less.

On the other hand, when the same treated oil was desalted using the conventional apparatus shown in FIG. 1, the result was 30 ppm.

As is clear from the above results, the present invention has the remarkable effect of significantly reducing the salt concentration in oil.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a conventional electrostatic desalination apparatus, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a schematic longitudinal cross-sectional view of an electrostatic desalination apparatus showing an embodiment of the present invention. 4 is a schematic cross-sectional view of the same, and FIG. 5 is a sectional view taken along the line v-■ in FIG. 4. l... Electrostatic demineralization tank, 2... Treated oil introduction pipe, 3...
・Distribution pipe, 4... Ground electrode, 5... High voltage electrode, 6
...Oil collecting pipe, 7...Transformer, 8...Insulator, 9...
- Interface meter, 10... Drain port, 11... Insulating bushing, 21a. 21b... Grid high voltage electrode, 22a, 22b... Grid ground electrode. Applicant's Attorney Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In an electrostatic desalination tank, a grid high-voltage electrode and a grid-shaped ground electrode paired with this electrode are arranged at an angle, and these 1
An electrostatic desalination device in which water droplets condensed between a pair of electrodes flow down a trough-shaped grounding ridge.