JPH0225644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil-water separation method and apparatus for separating water from an oil liquid containing water. More specifically, the present invention relates to a method and an apparatus for separating water containing fine dust from pyrolysis oil obtained by pyrolysis of naphtha.

[Background technology and its problems]

In fields such as the petroleum industry and petrochemical industry, removing free water contained in oil liquid is an extremely important operation.

Conventionally, as a method for removing free water contained in an oil liquid, the oil liquid is passed through a filter medium, specifically, a hydrophilic filter medium such as glass fiber wrapped in multiple layers. A method is known in which a minute amount of free water is coagulated and separated using the unique functions of the filter medium, such as the interfacial tension between liquid and liquid, and the difference in specific gravity, when passing between layers.

However, this agglomeration separation method has the disadvantage that the filter medium is clogged with minute dust contained in the oil liquid, and as a result, its separation function is impaired in a short period of time.

[Purpose of the invention]

An object of the present invention is to provide an oil-water separation method and apparatus which have an excellent oil-water separation effect and can maintain the oil-water separation effect for a long period of time.

[Means for solving problems and their effects]

First, in the oil-water separation method of the present invention, an oil liquid containing water, for example, the oil content of pyrolyzed oil obtained by thermal decomposition of naphtha, is passed through a water-repellent cylindrical net. It is characterized by separating the moisture inside.

The oil-water separator of the present invention is an apparatus for separating water from an oil containing water, and includes a separation means including a cylindrical net having water repellency, and an outer circumferential surface of the net of the separation means for separating water from an oil containing water. A means for sending liquid, a means for collecting oil in the oil liquid that has passed through the net of the separating means, and a means for collecting water in the oil liquid that cannot pass through the net of the separating means. shall be.

The present invention will be explained in detail below.

First, in the present invention, the term "water-repellent net" is sufficient as long as it has water-repellent properties at least on its surface, and includes, for example, a wire net coated with a water-repellent material.

Here, the size of the wire mesh may be appropriately selected depending on the amount of free water in the oil and the particle size and amount of dirt, but 100 to 300 mesh is usually suitable. Further, as the water-repellent material, polyethylene fluoride resin is suitable.

Since the net has water-repellent properties, when the oil in the oil passes through the net, water is repelled by the water-repellent property of the net, and the oil and water are separated here. The water that is repelled by the water-repellent net condenses into water droplets, which fall while sliding on the surface of the net. On the other hand, minute dirt in the oil liquid is captured on the surface of the screen, but is washed away as water droplets fall, so a high oil-water separation effect can be maintained for a long period of time without causing clogging.

The cylindrical shape of the water-repellent net has the effect of preventing the sent oil from deforming the net when it collides with the net, and also makes it easier to handle. If the cartridge is held by a perforated holding tube made of punched metal or the like, it has the advantage that it has sufficient strength and can be configured as a cartridge that is easy to replace. Moreover, when clogging occurs, it can be removed, cleaned, and reused.

〔Example〕

FIG. 1 shows an example of an oil-water separator according to the present invention. In the figure, the inside of a vertically elongated separation column 11 is partitioned into upper and lower chambers 13 and 14 by a partition wall 12 provided below the center position in the vertical direction. An oil liquid inlet 15 is opened in the upper side wall of the upper chamber 13 to introduce an oil liquid containing water, such as pyrolysis oil obtained by thermal decomposition of naphtha. At the bottom of the lower chamber 13, there is an oil extraction port 16 for extracting oil from which water has been separated from the oil liquid.
is opened.

Further, the partition wall 12 is provided with a moisture extraction pipe 17 that penetrates the lower chamber 14 and takes out the moisture accumulated in the upper chamber 13 to the outside of the tower, and a moisture extraction pipe 17 that penetrates the lower chamber 14 and takes out the moisture accumulated in the upper chamber 13 to the outside of the tower. A vertical tube 18 is provided. The bottom of the vertical pipe 18 is open to the chamber 14 below, and a separating cylinder 19 serving as oil/water separating means is detachably attached to the upper end of the vertical pipe 18 with a tightening nut 20.

As shown in FIG. 2, the separation tube 19 includes a cylindrical-shaped holding tube 22 made of punched metal (a material with many holes punched in a plate), and a plurality of holes in the holding tube 22. It is provided with a cylindrical mesh 21 arranged at a predetermined distance from and surrounding the outer periphery of the holding cylinder 22 via a crosspiece 23, and is configured in the shape of a cartridge that can be attached to and removed from the vertical tube 18. The mesh 21 is made of, for example, a wire mesh of about 100 to 300 meshes coated with a water-repellent material, here a polyfluorinated ethylene resin.

In such an apparatus, when an oil liquid containing water is introduced into the separation column 11 from the oil/water inlet 15,
The oil in the oil liquid sequentially passes through the net 21 and holding cylinder 22 of the separation tower 19, and then travels through the vertical pipe 18 and is stored in the chamber 14 below. After the oil in the chamber 14 is taken out from the oil extraction port 16, it is sent to the next treatment step.

On the other hand, when the oil passes through the net 21, the water in the oil is repelled by the water repellency of the net 21, condenses on its surface, becomes water droplets, and falls while sliding on the surface of the net 21. The oil and water in the oil liquid are separated.

At this time, the minute dust contained in the oil liquid is removed from the screen 21.
However, when the water droplets slide down the surface of the net 21, minute dirt is also washed away, so that a high oil-water separation effect can be maintained for a long period of time without causing clogging.

After the water containing dust flows down the surface of the screen 21, it is stored at the bottom of the upper chamber 13 and taken out from the water outlet 17 as appropriate.

Next, an example in which the oil/water separator shown in FIGS. 1 and 2 is applied to a naphtha thermal decomposition process will be described with reference to FIG. 3.

First, naphtha, which is a raw material, is pyrolyzed in a pyrolysis furnace 31. The gas obtained from the pyrolysis furnace 31 is rapidly cooled in a quencher 32 to prevent secondary reactions, and then introduced into an oil cooling tower 33, where the pyrolysis oil is recycled from the next stage water cooling tower 34. The cracked heavy oil is liquefied and separated. This cracked heavy oil is extracted from the bottom of the tower.

The gas extracted from the top of the oil cooling tower 33 is introduced into the water cooling tower 34, where the pyrolysis oil is liquefied and separated by water injected from the outside. This oil-water mixture of pyrolysis oil and water is passed through a plurality of guide plates 35.
A large number of corrugated sheets were laminated while being guided by
It is introduced into the CPI separator 36 and separated into water and pyrolysis oil. Water is extracted from the bottom of the tower by a pump or the like (not shown). Note that the sludge generated here is discharged into the sludge chamber 36A.

On the other hand, a part of the pyrolysis oil separated by the CPI separator 36 is transferred to the oil cooling tower 3 by a pump or the like.
However, the remainder is cooled in a cooler 37 and then sent to the oil-water separator of the present invention, where it is separated from oil and water.

In this treatment process, about 0.1
It contains % free water by weight and 0.43% by weight saturated dissolved water of the pyrolysis oil. Cooler 3
7, the solubility of water in the pyrolysis oil decreases to about 0.40% by weight of free water and 0.13% by weight of saturated dissolved water. Approximately 0.40% by weight
The pyrolysis oil containing free water is passed through an oil-water separator equipped with a 150-mesh water-repellent screen 21.

The microscopic debris contained in pyrolysis oil is 220 pieces/ml of particles less than 25μ, and 15 pieces/ml of particles larger than 25μ.
/ml, most of which passes through the net 21.
Some large debris is captured by the net 21, but it is washed away when the aggregated water droplets fall.
The network 21 of the oil-water separator was able to maintain its oil-water separation function for one year, and there was no need to replace the separation tube 19 at all during that time. Furthermore, the free water content in the pyrolysis oil at the oil extraction port 16 was reduced to 0.05% by weight or less.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an oil-water separation method and apparatus that have excellent oil-water separation effects and can maintain the oil-water separation effects for a long period of time.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the oil-water separator of the present invention, Fig. 2 is a diagram showing a separation cylinder, and Fig. 3 is a flowchart showing a naphtha pyrolysis treatment process using the oil-water separator of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 11...Separation tower, 15...Oil liquid inlet as liquid feeding means, 16...Oil extraction port as oil collection means, 17...Moisture extraction port as water collection means, 19
... Separation cylinder as separation means, 21 ... Net, 22
...Holding tube.

Claims (1)

[Scope of Claims] 1. In an oil-water separation method for separating water from an oil containing water, the oil in the oil is held in a perforated holding cylinder and coated with a water-repellent material. An oil-water separation method characterized by separating water from oil by passing it through a net. 2. The oil-water separation method according to claim 1, wherein the oil liquid is a pyrolysis oil obtained by pyrolysis of naphtha. 3. A device for separating water from an oil solution containing water, including a separation means including a perforated holding cylinder and a cylindrical net coated with a water-repellent material, and the oil liquid is applied to the outer peripheral surface of the net of the separation means. A means for sending liquid, a means for collecting oil in the oil liquid that has passed through the net of the separating means, and a means for collecting water in the oil liquid that cannot pass through the net of the separating means. Oil-water separator. 4. The oil-water separator according to claim 3, wherein the water-repellent mesh is a wire mesh coated with a polyfluorinated ethylene resin, which is the water-repellent material. 5. In claim 3 or 4, the separation means includes a cylindrical-shaped holding cylinder with holes made of punched metal, and a holding cylinder with holes arranged at a predetermined distance on the outer periphery of the holding cylinder with holes. An oil/water separation device comprising a cylindrical net coated with a retained water-repellent material. 6. The oil-water separator according to claim 5, wherein the separating means is configured in the form of a cartridge that has a self-cleaning ability as water droplets fall and is replaceable or reusable.