JPS5929077A - Separation column for cryohydrate - Google Patents

Abstract

PURPOSE:To provide a sepn. column for cryohydrate which can separate efficiently the cryohydrate from thick sea water in a sea water desalting device of a refrigeration type wherein liquefied gas is brought into direct contact with the sea water by providing brine outflow ports of a prescribed diameter or below in the part where the formed cryohydrate and the brine are separated. CONSTITUTION:A sepn. column 1 for cryohydrate is constituted of a slurry enriching section I , a driving section II and a liquid removing section III in sepn. mechanism. Cryohydrate 2 and brine 3 are separated in the section II and the stacked cryohydrate 2 is moved up into the section III where liquid is removed in a layer 4 and the cryohydrate 2 is desalted when the cryohydrate layer 4 rises higher than the ascending height of the brine 3 owing to the capillarity acting in said layer. The sepn. of the cryohydrate 2 and the brine 3 in the section IIis accomplished by brine outflow ports 5 and a meshed cylinder 6. The brine 3 past both is gathered in a brine receiver 7 and is discharged 8. When the diameter (d) of the ports 5 is determined at <=2.5mm., the projection of the cryohydrate 2 in a projecting shape into the ports 5 is prevented by the bridging phenomena in the ports 5, whereby the ascending of the cryohydrate layer is continuously accomplished and the brine is efficiently separated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ice crystal separation tower, and more specifically, ice crystals generated by direct contact between liquefied gas and seawater, and ice crystals generated by an adiabatic vacuum decomposition operation of hydrate, are separated from concentrated seawater. (
The present invention relates to an ice crystal separation column equipped with a separation section that can efficiently separate ice crystals from ice crystals (hereinafter abbreviated as brine).

In refrigerated seawater desalination equipment, ice crystals and prine are generally separated using a separation column. This separation method uses the buoyancy of ice crystals, which have a specific gravity smaller than that of ice crystals, and the upward force of the ice crystals due to the loss of fluid pressure caused by the plines flowing within the ice crystal layer in the separation section of the separation tower. This method takes advantage of the fact that the crystal layer rises above the brine liquid level. However, the forces that act in the opposite direction to the rise of the ice crystal layer include the weight of the ice crystal layer above the brine liquid level and the contact t between the tower wall surface and the ice crystal layer.
There is V rubbing. The weight of the ice crystal layer is inevitably determined by the height of the ice crystal layer, but the frictional force between the ice crystal layer and the tower wall depends on the material forming the wall, the smoothness tW of the wall, and the separation part. It depends on the 1'fl construction etc. The present invention was conceived with the idea of completely reducing the frictional force between the ice crystal layer and the tower wall surface.

That is, an object of the present invention is to provide an ice crystal separation tower that is fully equipped with a separation section that has a high separation performance of ice crystals and brine within the ice crystal separation tower, and that can reduce the sliding friction resistance of the inner wall of the separation tower. It is.

To summarize the present invention, the ice crystal separation tower 4 of the present invention is used in an ice crystal separation tower of a refrigerated seawater desalination apparatus using liquefied gas and seawater (K-contact contact), in a section for separating generated ice crystals and brine. , is characterized by having a plurality of brine outlet ports each having a diameter of 25 mm or less.

The ice crystal separation tower of the present invention has an ice crystal slurry concentrating section (center section), a driving section (center section), and a liquid removal section (
(upper part), on which a washing tower is installed. The feature of the present invention is mainly in the structure of the drive section, and ice crystals and brine are separated in the drive section by means of several brine outlet ports provided in the drive section. 72 on the outside if necessary
A 71 cylinder or a porous cylinder may also be provided, which is preferred. As shown in the drawing below, the diameter of the brine outlet is 2.
．． If it is larger than 5 degrees, the bridging phenomenon at the brine outlet is broken and the ice crystals protrude in a convex shape inside the brine outlet, and this convex protrusion becomes a large resistance to the upward movement of the ice crystal layer.

Therefore, the ice crystal slurry is concentrated to a certain degree in the concentrating section, and the brine flow resistance within the ice crystal layer becomes large, and the pushing up force due to the flow resistance becomes larger than the cutting force of the convex protrusion. Ice crystals piled up inside the ice crystal separation tower
rises rapidly. However, after rising for a certain amount of time, it stops. As described above, when the diameter of the brine outlet becomes larger than 2.5 mm, the rise of ice crystals l- becomes discontinuous.

In the present invention, by setting the diameter of the brine outlet to 2.5 mm or less, ice crystals do not protrude into the brine outlet in a convex manner due to a bridging phenomenon at the brine outlet, and the ice crystal layer rises. The inventors have confirmed the above fact through experiments, so
This will be explained with reference to the drawings.

Figure 1 is above the ice crystals stacked inside the ice crystal separation tower! This is a graph showing changes over time in 1-speed suction, where the solid line N indicates the case where the diameter of the brine outlet is 2.5 fi or less and the dotted line B exceeds 2.5 fi.

As is clear from Figure I61, in the case of the solid line A according to the present invention, the rising speed of the ice crystal layer is constant, and therefore it is easy to scrape off the ice crystals at the top of the ice crystal separation tower. In some cases, the rate of rise of the ice crystal layer changes over time, making it extremely difficult to scrape off the ice crystals at the top of the ice crystal separation tower. It has poor properties and causes extremely low desalination performance.

From the above, ice crystals formed by low-pressure crystallization pressure due to direct contact between liquefied gas and seawater, or small-sized particles (300 mm
The diameter of the brine outlet of the ice crystal layer nK% separation section used for the separation of ice crystals and brine from 1 to 1 ton (about 1 t) is required to be 25 mm or less.

Furthermore, the ice crystal separation tower in the present invention! It is desirable that the thickness of the wall forming the prine outlet at +''j is larger than the diameter of the brine outlet, since the brine flows through the brine outlet. The mesh circle 1h or porous cylinder is made of fine particles smaller than the particle size of the ice crystals in order to prevent the ice crystal layer from flowing out from the brine outlet at the beginning of slurry flow to the ice crystal separation tower, that is, before the formation of the ice crystal layer. (It is necessary to apply a sliding IJ method to the inner wall of the ice crystal separation tower. Therefore, it is effective to coat or embed a resin film, etc., which has low sliding frictional resistance, such as a resin film.

Next, the ice crystal separation tower of the present invention will be specifically explained with reference to the drawings. Fig. 2 is a schematic vertical cross-sectional view of the ice crystal layer of the present invention [one specific example of the t1# tower], and Fig. 3 is a schematic diagram of the ice crystal layer of the present invention [one specific example of the t1# tower]. It is an enlarged view showing the state of the separation section of the ice crystal separation tower drive section,
1 is an ice crystal separation tower, 2 is an ice crystal layer, 3 is brine, 4 is ice crystal j@, 5 is a brine outlet, 6 is a screen mesh,
7 is a brine receiver, 8 is a flow line outlet, 9 is an ice crystal separation tower slurry person, 10 is a conical part, 11 is an ice crystal protrusion part, 12 is an ice crystal layer upward flow, 13 is an ice crystal separation Tower top t<1;
, t is the thickness of the ice crystal molecule 'ifP tower wall, d is the diameter of the brine outlet, ■ is the concentration section, II is the drive section,
IL shows the deliquid section.

As shown in Fig. 2, the ice crystal separation tower ↓ consists of a slurry concentration section ■, a drive section II, and a liquid removal section Ill from the separation mechanism, and the ice crystal layer 2 and brine 3 are separated in the drive section ■. The ice crystal layer 2 is stacked and moves up the liquid removal section 1■, and the ice crystal I! When the height of the rise of the brine 3 due to the capillary phenomenon acting in the ice crystal layer 4 is exceeded, the liquid in the ice crystal layer 4 is removed and the ice crystals are desalinated. Separation of the ice crystal layer 2 and the brine 3 in the drive section (3) is performed by a brine outlet 5 and a screen menonu (metsu cylinder) 6 provided in the drive section 11.
The brine 3 that has passed through the brine outlet 5 and the screen mesh/yu 6 is collected in a brine receiver 7 and discharged through a brine discharge pipe 8.

The ice crystal slurry to the ice crystal separation tower 1 is sent by a pump or the like (not shown) and enters the slurry concentrating section ■ from the ice crystal separating tower slurry section 9, but there is a connection from this slurry section 9 to the concentrating section I. In order to prevent the flow from being disturbed due to rapid expansion of the slurry flow, a conical portion 10 is provided to widen at the end.

As shown in Fig. 3, when the diameter d of the brine outlet 5 is less than 2.5 mm, ice crystals protrude into the brine outlet 5 in a convex shape due to a bridging phenomenon. do not.

On the other hand, as shown in Figure 4, d is 2,
When it exceeds 5 fi, the bridging phenomenon collapses and the brine protrudes into the inside of the brine outlet 5 in a convex shape. As mentioned above, this creates a great resistance to the ice crystals' rise.

As shown in Fig. 4, the ice crystal slurry enters the ice crystal separation tower through the slurry inlet 9 into the slurry concentrating section I, where the slurry is concentrated by a certain iK and the brine flow resistance within the ice crystal layer is large. As mentioned above, when the pushing up force due to the flow resistance becomes larger than the cutting force of the convex ice crystal projection 11, the stacked ice crystal layer 4 rises sharply. but,
It will stop after rising for a certain amount of time. In order to prevent the discontinuity of the load in the ice crystal layer 4 that occurs in this way, in the present invention, the diameter d of the grain outlet is set to 2.5 as described above.
The mass sales F is made smaller, and the ice crystal layer 1 to 1f forming the brine outlet 5 is jψ of the tower wall t, which is smaller than the brine outlet 5.
It is preferable that the brine flow is t2d. In addition, it is essential that the screen mesh/unit 6 attached to the Pi 1 part as necessary has a mesh size smaller than the diameter of the ice crystal layer 2, and also the ice crystal separation tower ↓
As already mentioned, it is desirable to coat or line the inner wall with Teflon or the like in order to improve the separation performance of the Mizonari ice crystal separation tower ↓ of the present invention.

As explained above, according to the present invention, the amount of generated ice crystals and brine is n! It is possible to provide an ice crystal separation tower that can perform high performance.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the change over time in the top speed of the ice crystal layer stacked in the ice crystal separation tower, and Fig. 2 is a graph showing a specific example of the ice crystal separation tower of the present invention. ', Jj surface outline. Schematic diagram, Figure 3 shows the diameter of the old Blaino flow, 512.5 ra.
An enlarged view showing the state of the separation section in the ice crystal separation tower section !I!III section when the diameter is made smaller than n or more. Figure 4 shows the ice crystal separation when the diameter of the brine outlet is made larger than 2.5fi. It is an enlarged view showing the state of the separation section of the tower driving section. 1... Ice crystal separation tower, 2... Ice crystal layer, 3... Brine, 4... Quartz layer, 5 ...Brine outlet, 6...
・Screen Metsu/Yu, 7...Brine Reception, 8...
・Brine discharge pipe, 9... Ice crystal separation tower slurry population, 10... Cone part, 11... Ice crystal protrusion part, 12...
・Ice crystal no upward flow, 13...Ice crystal separation tower top, t...
・Thickness of ice crystal separation tower wall, d...Diameter of brine outlet,
■...Concentration section, ■...Drive 11th η Aya-pass B-! ? between (minute)

Claims (1)

[Scope of Claims] 1. In an ice crystal separation tower of a refrigerated seawater desalination apparatus that uses direct contact between liquefied gas and seawater, a part K separating generated ice crystals and brine, a brine flow having a diameter of 2.5 mm or more. An ice crystal separation tower characterized by having multiple outlets. 2. The ice crystal separation tower according to claim 1, wherein a mesh cylinder or a porous cylinder having side holes smaller than the particle diameter of ice crystals is attached to the outer periphery of the brine outlet. 3. The ice crystal separation NIL tower according to claim 1 or 2, in which the inner wall of the ice crystal separation tower is coated or lined with low sliding friction resistance.