Patent Description:
The present invention relates to a continuous centrifugal dewatering device (or a continuous centrifugal spin dryer), and more particularly, to a continuous centrifugal dewatering device having improved dewatering efficiency of a polymer slurry.

In general, a process of producing polymers includes polymerization, agglomeration, dewatering, and drying processes, and a polymer slurry produced through the polymerization and agglomeration processes contains a large amount of moisture.

During the drying process, a hot air drying method is generally used, which, however, incurs high energy cost, and thus, removing moisture of the polymer slurry as much as possible to lower a moisture content thereof during the dewatering process prior to performing the drying process is the key to improving economical efficiency of the processes.

As described above, a slurry cake having a low moisture content by removing a portion of moisture from the polymer slurry during the dewatering process may undergo a drying process so as to be obtained as a powdery polymer solid having a moisture content of less than <NUM>%.

During the dewatering process, it is common to go through a centrifugal dewatering device to primarily remove moisture, and among the centrifugal dewatering devices, a pusher-type continuous centrifugal dewatering device capable of performing a continuous process is used to increase productivity.

However, since the continuous centrifugal dewatering device of the related art simply dewaters using only centrifugal force, the dewatering efficiency is not excellent to lead to a problem that high energy cost is consumed during the drying process. In addition, when pores are developed inside polymer particles in the polymer slurry, moisture contained in the pores increases to lower the dewatering efficiency. An example of a filter centrifuge including drying step is known from <CIT>.

Therefore, there is a need to develop a continuous centrifugal dewatering device capable of solving the above problems.

An object of the present invention is to provide a continuous centrifugal dewatering device capable of improving dewatering efficiency of a slurry by using pressure and a blowing effect of a gas, as well as centrifugal force, by supplying the gas together with the slurry.

In one general aspect, a continuous centrifugal dewatering device includes: an external case having an internal space; a feed supply pipe to which a slurry as a mixture of a solid and a liquid is supplied; a basket provided inside the external case, configured to receive a first gas and the slurry provided thereto and rotate to apply centrifugal force to the slurry; a plurality of holes formed in the basket and configured to discharge a liquid filtered from the slurry to the outside of the basket; a pusher plate provided inside the basket and configured to discharge a slurry cake attached to an inner circumferential surface of the basket to the outside of the external case; a non-contact seal configured to prevent the first gas from flowing into a space between the external case and the basket; and a gas inlet to which a second gas, which flows in a reverse direction with respect to a flow direction of the first gas flowing to the space between the external case and the basket, is supplied.

In the continuous centrifugal dewatering device according to the present invention, a gas is supplied together with a slurry to improve the dewatering efficiency of the slurry by not only centrifugal force but also pressure and a blowing effect of the gas.

That is, by using the continuous centrifugal dewatering device according to the present invention during a dewatering process, it is possible to obtain a slurry having a moisture content as low as possible, thereby reducing energy consumed in a subsequent drying process.

Terms and words used in the present specification and claims are not to be construed as a general or dictionary meaning but are to be construed as meaning and concepts meeting the technical ideas of the present invention based on a principle that the inventors may appropriately define the concepts of terms in order to describe their own inventions in the best mode.

In the present invention, the term "slurry" may refer to a mixture of solid and liquid or a suspension in which fine solid particles are suspended in a liquid, and a "polymer slurry" may refer to a mixture of a solvent used in a polymerization and a solid such as a polymer generated by a polymerization or a suspension in which the solids are suspended in the solvent.

In the present invention, the term "slurry cake" may refer to a solid after dewatering and filtration of the slurry.

Hereinafter, the present invention will be described in more detail with reference to the following drawings in order to help understand the present invention.

According to the present invention, a continuous centrifugal dewatering device is provided. The continuous centrifugal dewatering device includes: an external case <NUM> having an internal space; a feed supply pipe <NUM> to which a slurry as a mixture of a solid and a liquid is supplied; a basket <NUM> provided inside the external case <NUM>, configured to receive a first gas and the slurry provided thereto and rotate to apply centrifugal force to the slurry; a plurality of holes <NUM> formed in the basket <NUM> and configured to discharge a liquid filtered from the slurry to the outside of the basket <NUM>; a pusher plate <NUM> provided inside the basket <NUM> and configured to discharge a slurry cake <NUM> attached to an inner circumferential surface of the basket <NUM> by centrifugal force to the outside of the external case <NUM>; a non-contact seal <NUM> configured to prevent the first gas from flowing into a space between the external case <NUM> and the basket <NUM>; and a gas inlet <NUM> to which a second gas, which flows in a reverse direction with respect to a flow direction of the first gas flowing to the space between the external case <NUM> and the basket <NUM>, is supplied.

In general, a process of producing a polymer includes polymerization, agglomeration, dewatering and drying processes, and a polymer slurry produced through the polymerization and agglomeration processes contains a large amount of moisture.

However, since the continuous centrifugal dewatering device of the related art simply dewaters using only centrifugal force, the dewatering efficiency is not excellent to lead to a problem that high energy cost is consumed during the drying process. In addition, when pores are developed inside polymer particles in the polymer slurry, moisture contained in the pores increases to lower the dewatering efficiency.

Therefore, the present invention provides a continuous centrifugal dewatering device capable of improving dewatering performance of a slurry by supplying the slurry together with a gas. That is, by using the continuous centrifugal dewatering device according to the present invention during a dewatering process, it is possible to obtain a slurry having a moisture content as low as possible, thereby reducing energy consumed in a subsequent drying process.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may be a continuous centrifugal dewatering device in which a slurry containing a solid and a liquid and a first gas are supplied together to improve dewatering efficiency of the slurry using pressure and blowing effect of the first gas, as well as centrifugal force.

As a specific example, the continuous centrifugal dewatering device may be a device for applying centrifugal force to the slurry to separate a liquid contained in the slurry by a difference in specific gravity and generate and discharge the slurry cake <NUM> without the liquid. As a more specific example, in addition to the slurry, a first gas may be additionally supplied to provide an additional dewatering effect to the slurry by pressure and blowing effect of the gas.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include an external case <NUM> having an internal space.

The external case <NUM> may include a liquid outlet <NUM> through which a liquid filtered from the slurry is discharged, a slurry cake outlet <NUM> through which the slurry cake <NUM> is discharged, and a gas outlet <NUM> through which the first gas is discharged.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include a feed supply pipe <NUM> to which a slurry of a mixture of solid and water is supplied.

The feed supply pipe <NUM> may extend into the inside of the basket <NUM> to be described later to supply the slurry into the inside of the basket <NUM>. As described above, the slurry may be formed by mixing a solid and a liquid, and as a specific example, the slurry may be a polymer slurry produced by a polymerization.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include the basket <NUM> provided inside the external case <NUM>, receiving the first gas and the slurry supplied thereto, and rotating to apply centrifugal force to the slurry.

For example, the basket <NUM> may have a cylindrical shape. As a more specific example, the basket <NUM> may apply centrifugal force to the slurry, while rotating, the slurry is attached to an inner circumferential surface of the basket <NUM> by centrifugal force and a liquid is filtered from the slurry through the plurality of holes <NUM> to be described later, and the filtered liquid may be discharged to the outside of the basket <NUM>.

The basket <NUM> may include a rotation driving unit <NUM> for performing a rotational motion of the basket <NUM>. For example, the rotation driving unit <NUM> may include a power unit (not shown) and a power transmission unit (not shown), but the rotation driving unit is not limited thereto and may include any unit capable of performing a rotational motion of the basket <NUM>.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include the plurality of holes <NUM> formed in the basket <NUM> and discharging the liquid filtered from the slurry to the outside of the basket <NUM>.

For example, when the basket <NUM> has a cylindrical shape, a plurality of holes <NUM> may be formed along a circumference of the basket <NUM>. In this case, the plurality may refer to one or more. That is, the plurality of holes <NUM> may refer to one or more holes.

The plurality of holes <NUM> may include holes having a diameter through which the liquid filtered from the slurry passes and the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> does not pass. Accordingly, the slurry cake <NUM> may not be discharged through the plurality of holes <NUM> and only the liquid may be discharged.

As described above, the liquid may be filtered from the slurry through the plurality of holes <NUM> included in the basket <NUM>, and the filtered liquid may be discharged to the outside of the basket <NUM>, that is, a space between the basket <NUM> and the external case <NUM>.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include the pusher plate <NUM> provided inside the basket <NUM> and discharging the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> to the outside of the external case <NUM>.

The continuous centrifugal dewatering device may filter the liquid from the slurry by centrifugal force to form the slurry cake <NUM> in which the liquid is filtered out. As a specific example, centrifugal force may be applied to the slurry by a rotational motion of the basket <NUM>, and accordingly, the slurry may be attached to the inner circumferential surface of the basket <NUM> by a force distributed in a direction of the inner circumferential surface of the basket <NUM>, and, at the same time, the liquid included in the slurry may be discharged through the plurality of holes <NUM> included in the basket <NUM>. Here, the slurry cake <NUM> without a liquid may be attached to the inner circumferential surface of the basket <NUM> without being discharged to the outside of the basket <NUM>.

In this manner, a reciprocating motion of the pusher plate <NUM> may be performed to discharge the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> to the outside of the external case <NUM>, that is, to the outside of the continuous centrifugal dewatering device.

For example, the liquid included in the slurry supplied through the feed supply pipe <NUM> may be filtered out, i.e., separated, by centrifugal force due to the rotational motion of the basket <NUM>, and thus, the slurry cake <NUM> attached to and formed on the inner circumferential surface of the basket <NUM> may be discharged to the outside of the continuous centrifugal dewatering device by the reciprocating motion of the pusher plate <NUM>.

Here, after the liquid is discharged to the space between the basket <NUM> and the external case <NUM>, the liquid may be discharged to the outside of the external case <NUM>, i.e., to the outside of the continuous centrifugal dewatering device through the liquid outlet <NUM> included in the external case <NUM>.

In addition, the slurry cake <NUM> may be discharged to the outside of the external case <NUM>, i.e., to the outside of the continuous centrifugal dewatering device, through the slurry cake outlet <NUM> included in the external case <NUM> by the reciprocating motion of the pusher plate <NUM>. The pusher plate <NUM> may perform a continuous reciprocating motion, and thus the slurry cake <NUM> may be continuously discharged.

The pusher plate <NUM> may include a pusher system <NUM> for reciprocating the pusher plate <NUM>. For example, the pusher system <NUM> may include a power unit (not shown) and a power transmission unit (not shown), but is not limited thereto, and may include any unit capable of performing a reciprocating motion of the pusher plate <NUM>.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may further include a dispersing plate <NUM> provided inside the basket <NUM> and dispersing the slurry supplied from the feed supply pipe <NUM> in the basket <NUM>.

The dispersing plate <NUM> may serve to uniformly disperse the slurry supplied from the feed supply pipe <NUM> in the inside of the basket <NUM>, while being reflected by the dispersing plate <NUM>. As such, since the slurry is uniformly dispersed inside the basket <NUM>, the slurry to which centrifugal force is applied may be attached to the inner circumferential surface of the basket <NUM> with a uniform thickness, thereby maximally improving dewatering performance.

The dispersing plate <NUM> may further include a support <NUM> connected to the feed supply pipe <NUM> to support the dispersing plate <NUM>. That is, the dispersing plate <NUM> may be fixed to the inside of the basket <NUM> by the support <NUM> connected to the feed supply pipe <NUM>.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may additionally supply a first gas to the inside of the basket <NUM>.

In addition, the continuous centrifugal dewatering device according to the present invention may further include a gas supply pipe <NUM> for supplying the first gas to the inside of the basket <NUM>.

Accordingly, the first gas may be mixed with the slurry to form a mixed feed so as to be supplied to the feed supply pipe <NUM> or may be independently supplied through the gas supply pipe <NUM>. Here, even if the first gas is independently supplied through the gas supply pipe <NUM>, the first gas may be mixed with the slurry supplied to the feed supply pipe <NUM> by the rotational motion of the basket <NUM>.

The gas supply pipe <NUM> may extend into the inside of the basket <NUM> to supply the first gas to the inside of the basket <NUM>, and the first gas supplied to the inside of the basket <NUM> may be discharged to the outside through the plurality of holes <NUM> included in the basket <NUM> or through the gas outlet <NUM> included in the external case <NUM> after passing through the space between the external case <NUM> and the basket <NUM>.

As a specific example, the gas supply pipe <NUM> may include a plurality of pores formed in a longitudinal direction. In this case, the first gas may be uniformly supplied to the inside of the basket <NUM> through the plurality of pores, and thus, the first gas may be uniformly mixed with the slurry.

As such, when the first gas is additionally supplied in addition to the slurry supplied to the inside of the basket <NUM>, the dewatering efficiency of the slurry may be improved by using the pressure and blowing effect of the first gas as well as centrifugal force.

Specifically, when the first gas is supplied to the inside of the basket <NUM>, pressure of the first gas may act on the slurry dispersed in the inner circumferential direction of the basket <NUM> by centrifugal force to further improve the operation of filtering the liquid from the slurry. In addition, the dewatering effect by blowing may be added to the slurry cake <NUM> in the process in which the first gas passes through the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> by centrifugal force and is discharged through the plurality of holes <NUM> of the basket <NUM>.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include the non-contact seal <NUM> preventing the first gas from flowing into the space between the external case <NUM> and the basket <NUM>.

As described above, the first gas supplied into the basket <NUM> may pass through the space between the external case <NUM> and the basket <NUM> in addition to the plurality of holes <NUM> included in the basket <NUM>, and then be discharged to the outside through the gas outlet <NUM> included in the external case <NUM>. In this case, a problem arises in that the dewatering effect may be reduced due to the blowing that occurs in the process in which the first gas passes through the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> and is discharged through the plurality of holes <NUM> of the basket <NUM>.

In order to solve this problem, in the present invention, the non-contact seal <NUM> is provided in the space between the external case <NUM> and the basket <NUM> to prevent the first gas from flowing into the space between the external case <NUM> and the basket <NUM>, thereby increasing a flow rate of the first gas passing through the slurry cake <NUM>. Accordingly, there is an effect of improving the dewatering effect acting on the slurry cake <NUM>.

The non-contact seal <NUM> may be attached to the external case <NUM> and spaced apart from the basket <NUM> or may be attached to the basket <NUM> and spaced apart from the external case <NUM>. As such, when a space <NUM> exists between the non-contact seal <NUM> and the basket <NUM>, frictional contact between the non-contact seal <NUM> and the basket <NUM> due to the rotational motion of the basket <NUM> may be reduced to prevent a deterioration of durability, thereby improving long-term operation characteristics of the continuous centrifugal dewatering device. In addition, when a space exists between the non-contact seal <NUM> and the external case <NUM>, frictional contact between the non-contact seal <NUM> and the external case <NUM> due to the rotational motion of the basket <NUM> may be reduced to prevent a deterioration of durability, thereby improving long-term operation characteristics of the continuous centrifugal dewatering device.

For example, referring to <FIG> showing a cross-sectional view in an A-B direction of the continuous centrifugal dewatering device according to the present invention shown in <FIG>, since the space <NUM> exists between the non-contact seal <NUM> and the basket <NUM>, frictional contact between the non-contact seal <NUM> and the basket <NUM> due to the rotational motion of the basket <NUM> may be prevented.

In addition, <FIG> shows an embodiment in which the non-contact seal <NUM> is attached to the external case <NUM>.

Referring to <FIG>, the non-contact seal <NUM> may be attached to the external case <NUM> or the basket <NUM> by coupling using a bolt <NUM> or the like. In a specific example, a portion of the external case <NUM> may be divided, the non-contact seal <NUM> may be inserted into the portion of the divided external case <NUM>, and the divided external case <NUM> may be coupled using the bolt <NUM> or the like, thereby fixing the non-contact seal <NUM>, but an attaching method of the non-contact seal <NUM> is not limited thereto.

The non-contact seal <NUM> may be provided, for example, in a labyrinth shape and may be formed of white metal, brass pins, nickel pins, or the like. As shown in <FIG>, the non-contact seal <NUM> may have a sharp shape in a direction adjacent to a contact portion, so that even if the non-contact seal <NUM> comes into contact with a component of the continuous centrifugal dewatering device, only the contact portion of the non-contact seal <NUM> may melt to prevent damage of the external case <NUM> or the basket <NUM> that may come into contact with the non-contact seal <NUM> due to frictional contact.

According to an embodiment of the present invention, the continuous centrifugal dewatering device according to the present invention may include the gas inlet <NUM> through which a second gas, which flows in a reverse direction with respect to a flow direction of the first gas flowing to the space between the external case <NUM> and the basket <NUM>, is supplied.

Even if the non-contact seal <NUM> is provided in the space between the external case <NUM> and the basket <NUM>, the space exists to be separated from the basket <NUM> or the external case <NUM> as described above. Therefore, in order to prevent the first gas from flowing into the space, a flow path of the first gas may be changed into the inside of the basket <NUM> by supplying the second gas flowing in the reverse direction with respect to the flow direction of the first gas.

For example, when the basket <NUM> has a cylindrical shape, the gas inlet <NUM> may be provided in the form of one or more pores formed along the circumference of the basket <NUM>, but is not limited thereto.

In this manner, when the second gas is supplied through the gas inlet <NUM>, a flow rate at which the first gas flows into the space between the external case <NUM> and the basket <NUM> may be reduced by <NUM>% or more, <NUM>% or more, or <NUM>% or more, compared to the case where the second gas is not supplied.

The second gas supplied through the gas inlet <NUM> may pass through the slurry cake <NUM> attached to the inner circumferential surface of the basket <NUM> and be discharged through the plurality of holes <NUM> included in the basket <NUM>. In this process, a dewatering effect by blowing may be added to the slurry cake <NUM>. That is, by further imparting the dewatering effect based on blowing to the slurry cake <NUM> with the second gas as well as the first gas described above, there is an effect of further lowering the moisture content of the slurry cake <NUM>.

The second gas discharged through the plurality of holes <NUM> included in the basket <NUM> may be discharged to the outside through the gas outlet <NUM> included in the external case <NUM>.

According to an embodiment of the present invention, the first gas and the second gas may be the same or different from each other, and may independently be air in the atmosphere or an inert gas.

As a specific example, the first gas and the second gas may be the same or different from each other and may independently include one or more inert gases selected from the group consisting of nitrogen, neon, helium, and argon. As such, when the first gas and the second gas each include an inert gas, explosion or fire due to contact with oxygen may be prevented.

As a more specific example, when the slurry is a polymer slurry, the first gas and the second gas may each include an inert gas, thereby preventing an additional side reaction of the polymer.

In addition, the gas is used for dewatering of the slurry, and a gas having moisture content of <NUM>% or less, <NUM>% or less, or <NUM>% or less may be used.

According to an embodiment of the present invention, the first gas and the second gas discharged to the outside of the external case <NUM> may be re-introduced into the inside of the basket <NUM>. That is, the first gas and the second gas discharged to the outside of the basket <NUM> may be discharged to the outside of the external case <NUM> through the gas outlet <NUM>, and then re-introduced into the inside of the basket <NUM>.

Here, the first gas and the second gas may be re-introduced through the feed supply pipe <NUM> or the gas supply pipe <NUM>. In order for the first gas and the second gas to be re-introduced through the feed supply pipe <NUM>, a pipe connecting the gas outlet <NUM> and the feed supply pipe <NUM> may be further provided, and in a case in which the first gas and the second gas are re-introduced through the gas supply pipe <NUM>, a pipe connecting the gas outlet <NUM> and the gas supply pipe <NUM> may be further provided.

According to an embodiment of the present invention, the liquid discharged through the liquid outlet <NUM> and the slurry cake <NUM> discharged through the slurry cake outlet <NUM> may have a downward flow inside the basket <NUM> due to a difference in density with the first gas, and the first gas or the second gas discharged through the gas outlet <NUM> may have an upward flow inside the basket <NUM> due to a difference in density between the liquid and the slurry cake <NUM>.

Accordingly, the liquid outlet <NUM> and the slurry cake outlet <NUM> may be included at a lower portion of the external case <NUM>, and the gas outlet <NUM> may be included at an upper portion of the external case <NUM>. Here, the "upper portion" may refer to a portion corresponding to a height of <NUM>% or higher, <NUM>% or higher, or <NUM>% or higher from a total height of the external case <NUM>, and the "lower portion" may refer to a portion corresponding to a height less than <NUM>%, less than <NUM>%, or less than <NUM>% from the total height of the external case <NUM>.

According to an embodiment of the present invention, since the continuous centrifugal dewatering device according to the present invention includes the non-contact seal <NUM> and the gas inlet <NUM> for preventing the first gas from flowing into the space between the external case <NUM> and the basket <NUM> while the first gas is supplied, the dewatering performance of the slurry may be further improved, compared to the continuous centrifugal dewatering device of the related art.

In particular, when the slurry is a polymer slurry, a dewatering rate of moisture contained in the pores of polymer particles with developed pores may be increased to obtain the slurry cake <NUM> having a moisture content less than <NUM>%, less than <NUM>%, or less than <NUM>% from the polymer slurry. Accordingly, energy consumed during a subsequent drying process may be reduced.

Claim 1:
<NUM>. A continuous centrifugal dewatering device comprising:
an external case (<NUM>) having an internal space;
a feed supply pipe (<NUM>) to which a slurry as a mixture of a solid and a liquid is supplied;
a basket (<NUM>) provided inside the external case (<NUM>), configured to receive a first gas and the slurry provided thereto and rotate to apply centrifugal force to the slurry;
a plurality of holes (<NUM>) formed in the basket (<NUM>) and configured to discharge a liquid filtered from the slurry to the outside of the basket (<NUM>);
a pusher plate (<NUM>) provided inside the basket (<NUM>) and configured to discharge a slurry cake attached to an inner circumferential surface of the basket (<NUM>) to the outside of the external case (<NUM>); characterised by
a non-contact seal (<NUM>) configured to prevent the first gas from flowing into a space between the external case (<NUM>) and the basket (<NUM>); and
a gas inlet (<NUM>) to which a second gas, which flows in a reverse direction with respect to a flow direction of the first gas flowing to the space between the external case (<NUM>) and the basket (<NUM>), is supplied.