JPH038804B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Industrial Application Field The present invention involves partially dehydrating a stock solution containing a dilute solid suspension (hereinafter abbreviated as SS component) by over-operation to remove the SS component. The present invention relates to a concentrator for increasing concentration and a method for operating the same.

In general, large-scale over-dehydration equipment can be roughly divided into filter press type, belt press type, and rotary type (centrifugal) type, but in all types of over-dehydration equipment, materials with a thin SS component are directly passed through the above-mentioned over-dehydration equipment. If the dewatering process is carried out after the dehydration process is performed, the operating efficiency of the machine will be poor. Recently, in order to improve the operating efficiency of the equipment and save energy, there has been a demand for increasing the concentration of SS components before applying it to the dehydration equipment, and then applying it to the over-dehydration equipment. There was nothing suitable in terms of performance, mechanical reliability, etc.

In response to such industrial needs, the present invention provides a simple and efficient superconcentration device and an efficient method of operating the same.

Another advantage of the device according to the present invention is
The advantage is that it can also wash SS components.

Recently, with the progress of new industries such as new ceramics and electronic materials, it has become necessary to obtain a cake containing as few impurities as possible at the stage of preparing these raw materials.

Therefore, there has been a demand for the development of a filtration device that reduces impurities in the mother liquor containing SS components as much as possible during the overstep, that is, a concentration filtration device that has a novel washing effect.

The filtration device according to the present invention not only enables effective concentration but also so-called washing, which can minimize impurities in the slurry mother liquor by adding an operation of injecting washing water from the side wall of the outer cylinder.・It can also be applied as a concentrator.

(2) Conventional technology Suspension concentration machines include (i) pressure flotation concentration;
(ii) Fixed cloth concentration using siphon pressure, (iii) Running cloth concentration using siphon pressure, (iv) Sedimentation separation, (v) Centrifugation,
(vi) Rotary multi-stage continuous concentrator (e.g.
15954, 52-24383, 36-3448, 36-3794, 36-
5940 etc.) are known.

Among these, rotary type, multi-stage, continuous, concentrated,
I would like to specifically cite and explain (vi) as a conventional technique similar to the present invention in terms of cleaning.

The same format is basically 1972.
-15954, the same type of alternating stacked disc-shaped rotary filter body and disc-shaped fixed filter body as shown in JP-A-52-24384
Rotating disks (without filters) are stacked alternately between the disk-shaped fixed filters seen in the figure, and while injecting the washing liquid through the gaps between the fixed filters, the slurry is sheared, stirred and washed, and the liquid is A typical example is one in which the slurry is extracted while passing through a fixed disk-shaped filter, and washing and slurry concentration can also be performed.

These devices have received a fair amount of praise as devices that can wash and concentrate SS components.

(3) Problems to be Solved by the Invention However, these devices consist of alternating stacks of disc-shaped rotating bodies and disc-shaped filters, making them complicated and expensive.

In addition, although cake adhesion and clogging are small due to the shear force of high-speed turbulent liquid, when clogging occurs on the side surface of the disk, it is necessary to remove it by means such as disassembly, cleaning, or remove it from the outside. Pressurize the washing water,
The operation was complicated due to methods such as introduction.

[Reference: Product name “Rotary Filter Press” Catalog: Kotobuki Kogyo Co., Ltd.]

(4) Means to solve the problems The above-mentioned drawbacks of conventional products, namely complexity and high cost: We have improved the complexity of operations during fabric recycling and backwashing to make them simpler and provide cheaper concentration (washing). In order to provide a device, the present invention: An inner cylinder having a cylindrical surface on the outer periphery is housed in a fixed outer cylinder, and this is rotated; An extremely simple structure consisting of two cylinders; It is characterized by certain points.

(i) During overconcentration, the stock slurry is forced into the concentric cylindrical space between the inner and outer cylinders, and the pressure causes the liquid to flow into the rotating inner cylinder, leaving the SS component on the surface. .

However, due to the dissipation effect caused by centrifugal force and the strong stirring effect caused by the rotation of the inner cylinder, the SS component cake on the surface does not become thick, resulting in a so-called thin layer cake. It also has the advantage of very little degradation.

(ii) If the surface becomes clogged due to continuous use,
While the inner cylinder continues to rotate, the supply of stock solution is stopped and the liquid in the concentric cylindrical space is drained to return to normal pressure.
Increase the rotation speed of the cylinder.

The structure is such that some liquid remains inside the inner cylinder, and due to the centrifugal force increased by the increased rotation speed, this residual liquid sticks to the entire inside of the overbody, penetrates it, and jumps out to the outside, causing the overbody to explode. is sufficiently backwashed and regenerated.

Due to the centrifugal force, excess material on the surface of the inner cylinder, such as cloth, wire mesh, etc., swells outward, and the pore diameter becomes slightly larger, which is extremely convenient for backwashing from the inner surface.

(iii) Particularly when concentrating a slurry that requires a high-purity cake, feeding fresh water (or solvent) in multiple stages from the supply channel installed in the outer cylinder has the effect of replacing the mother liquor containing impurities and reducing the concentration of water in the slurry. Due to the effects of shearing and stirring the SS component, a concentrated product of the SS component with less foreign impurities can be obtained.

(5) Numerical explanation of action and mechanism The following formula [] is a formula to calculate the pressure due to the centrifugal force generated on the inner surface of a rotating cylindrical body filled with water.

P=1/3r ² w ² ρ [] P: Kg/m ² ρ: Kg・^sec2 m ⁴ [For water, ρ=1000/9.81] r: m (radius) w: rad/sec = 2πN/60 The relationship between the rotational speed N (RPM) of the cylindrical body and P is obtained from the above equation and is shown in FIG.

The operation and mechanism of the (washing) concentrating device according to the present invention will be numerically explained with reference to FIG.

For example, a rotating inner cylinder with an inner diameter of 20 cm has approximately 0.01 kg/kg at the circumferential surface at N (rotation speed) of 100 RPM.
Generates an internal pressure of cm ² .

Therefore, when forcing the liquid into the inner cylinder by force, the pressure for pushing the liquid into the concentric cylinder is
The higher the value, the better, but considering the pressurizing energy, it is desirable that P be at least 0.1 Kg/cm ² or less.

Next, in the case of backwashing, as mentioned above, the stock solution supply pipe 6
When the valve of the slurry discharge pipe 7 is closed and the valve of the slurry discharge pipe 7 is opened, the inside of the concentric cylindrical space becomes normal pressure.

If the N in the inner cylinder is increased to 500 RPM in this state, it will be 0.3Kg/cm ² and the liquid in the inner cylinder will be over5
The slurry flows through the slurry, backwashes it, jumps out into the concentric cylindrical space, and is further discharged from the slurry discharge pipe 7.

The interior of the inner cylinder is made into a multi-stage type in consideration of improving strength and cleaning efficiency, and a partition wall 12 is provided for each stage.
It has a structure in which a small amount of water remains at the top, and as the rotation speed of the inner cylinder increases, this water crawls up the inner wall of the inner cylinder and is spouted out from the entire surface of the overbody due to centrifugal force.
Perform backwashing of excess body.

The filtration and backwashing are performed automatically from the outside to the inside (
The operation is extremely simple as the flow is from inside to outside (backwash).

Of course, as can be seen in the figure, the centrifugal force generated within the inner cylinder also differs depending on the diameter of the inner cylinder, so the optimum rotation speed is determined by also taking into account the diameter of the inner cylinder.

Generally speaking, at the stage of overconcentration, it is better to have a higher rotational speed N for shearing and stirring at the surface of the inner cylinder, while on the other hand, from the point of view of liquid injection energy, a lower N is better. It's advantageous.

On the other hand, in the backwashing stage, the backwashing liquid permeates (inside → outside).
In terms of speed, P is large, so it is better to have N larger, but on the other hand, in terms of vibration, strength, and energy of the rotating body (inner cylinder), it is better to have smaller N.

Taking all the above into consideration, as shown in Fig. 4, the generated pressure P at the inner cylinder peripheral wall as shown in Equation 1 is
However, it is a cycle in which filtration is performed at a rotation speed such that the rotation speed is 0.1Kg/cm ² or less, and backwashing is performed at a rotation speed such that the rotation speed is 0.3Kg/cm ³ or more. The conclusion was reached that it was economically advantageous.

The rotational speed of the inner cylinder is controlled by a driving device installed at the end of the inner cylinder, such as indirect control by an oil turbine, direct control by a thyristor-based electric motor, gears, booleys, etc.
In addition to the opening and closing operations of the drain valve, a program sequencer is incorporated, allowing comprehensive control of the entire system.

(6) Example FIG. 1 shows an example in which the filtration apparatus according to the present invention is applied to concentration. In this case, the valve of the cleaning water supply pipe 10 is closed and fresh water is not supplied.

FIG. 2 shows an example in which the slurry (cake) is washed and concentrated. In this case, fresh water (or solvent) is fed into the outer cylinder wall in multiple stages and is separated into the inner cylinder together with the mother liquor in the slurry containing impurities, and the SS portion is repeatedly washed in the later stages. ,
It is purified and concentrated and discharged at the other end.

The overbody 5 stretched over the outer peripheral surface of the inner cylinder is wire mesh,
Cloth, porous sintered body, foam, etc. are used.

In addition, the overbody is generally made of a very fine material, which is weak and bulges due to press-fitting or centrifugal force. At the same time, using the tightening band 14 on the outer surface of the inner cylinder,
Protecting your body.

In order to prevent a direct short circuit from the slurry inlet to the outlet and to improve the cleaning effect, the apparatus has a multi-stage structure with baffles 11 and partition walls 12 provided inside and inside the outer cylinder.

Although this device can be installed in either a horizontal type or a rigid tower type, installation in a rigid tower type is preferred from the viewpoints of strength, vibration prevention, and space savings.

(7) Effects of the Invention As shown in the text and the figures, the concentrating device according to the present invention consists of (i) an inner cylinder with a simple cylindrical overbody, (ii) a fixed outer cylinder, and (iii) It has an extremely simple structure consisting of a drive device for rotating the inner cylinder, and can be manufactured at low cost. And, for backwashing, stop the liquid supply, (i) drain the liquid from the concentric cylindrical space inside the device, and (ii)
This is possible by simply increasing the rotational speed of the inner cylinder, and it is extremely advantageous because filtration (concentration and cleaning of slurry) and backwashing (surface regeneration) can be performed reliably by repeating simple operations. .

[Brief explanation of the drawing]

Fig. 1 shows a schematic diagram of the filtration device according to the present invention when used for slurry concentration, and Fig. 2 shows a schematic diagram of the device and attached equipment when concentrating while washing.
Shows the tank and piping system. Figure 3 shows a system diagram during backwashing and regeneration of excess waste. FIGS. 4A, 4B, and 4C are cross-sectional views taken along YY, PQ, and MN planes shown in the figures, respectively. FIG. 5 shows the relationship between the rotational speed of the inner cylinder and the pressure generated by centrifugal force on the inner surface of the inner cylinder, calculated using the formula shown in the text. Symbols, numbers, and names used in the figures and text are written in the margins of each leaf.

Claims (1)

[Claims] 1. Having a slurry inlet at one end and an outlet at the other end,
In a filtration device consisting of a fixed outer cylinder and a cylinder having a filtration surface on the peripheral wall and a structure capable of rotating around the center of the cylinder, the inner and outer cylinders are rotated while the inner cylinder is rotated. A dilute slurry is press-fitted into one end of the concentric cylindrical space between the two, and while resisting the centrifugal force of the liquid in the inner cylinder, it is filtered into the inner cylinder.While water is being removed from the slurry, concentrated slurry is introduced from the other end. A filtration/concentration device characterized by discharge. 2. A fixed outer cylinder having a slurry inlet at one end and an outlet at the other end as described in Claim 1 above; having a filtering surface on the peripheral wall and rotating around the center of the cylinder. In a filtration device consisting of a cylinder with a structure that allows for A filtration/concentration device is characterized in that filtering is carried out under pressure into an inner cylinder while resisting water pressure, and water is removed from the slurry while the concentrated slurry is discharged from the other end. , While the slurry is moving from the inlet to the other end, the liquid components containing impurities in the raw slurry and a part of the added cleaning liquid are pressure filtered into the inner cylinder, and the SS components in the slurry are washed.
A filtration and concentration device with added cleaning effect, which is characterized by purifying and concentrating. 3 A fixed outer cylinder having a slurry inlet at one end and an outlet at the other end; A cylinder having a filtration surface on the peripheral wall and having a structure capable of rotating around the center of the cylinder;
In a filtration device, a dilute slurry is press-fitted into one end of the concentric cylindrical space between the inner and outer cylinders while the inner cylinder is rotated, and the filtrate is pumped inside while resisting the centrifugal force of the liquid in the inner cylinder. In a filtration concentration cleaning device characterized by performing pressure filtration and water removal from the slurry inside the cylinder, and discharging the concentrated slurry from the other end,
After stopping the slurry supply and opening the outlet valve to remove the remaining slurry and reducing the pressure in the inner and outer concentric cylindrical spaces, the rotation speed of the inner cylinder is increased and the increased centrifugal force causes the remaining slurry to remain in the inner cylinder. A filtration and concentration method characterized in that the filtrate flows out of the inner cylinder to backwash the clogging of the filtration surface and regenerate the filtration body. 4 In the filtration concentration method shown in claim 3, the following formula P=1/3r ² ω ² ρ However, P=Kg/m ² , r: m (radius) ω: rad/sec [2rN/60 ] Filtering is performed at a rotation speed N such that the pressure P generated by the centrifugal force on the inner circumferential wall of the inner cylinder, which is accounted for by N: rotational speed rpm, ρ: Kg・sec/m ² , is 0.1 Kg/cm ² or less, A filtration and concentration method characterized by backwashing at a rotation speed of 0.3Kg/cm ² or more.