JP3824966B2 - Synthetic resin particle cleaning method and cleaning apparatus used therefor - Google Patents

Description

【００７８】
【発明の効果】
本発明の合成樹脂粒子の洗浄方法は、水性媒体中に合成樹脂粒子が分散してなるスラリーを一定量、濾過洗浄機に供給して濾過すると共に上記濾過洗浄機から排出される濾過排出液量を測定する工程と、この測定された濾過排出液量の総量が一定量に達した時点で、上記濾過洗浄機内に一定量の洗浄液を供給することにより上記スラリーの濾過によって得られた濾過ケーキを洗浄すると共に上記濾過洗浄機から排出される洗浄排出液量を測定する工程と、この測定された洗浄排出液の総量が一定量に達した時点で、上記濾過洗浄機による濾過ケーキの洗浄を停止する工程とからなることを特徴とするので、濾過洗浄機の濾過材の目詰まり具合に左右されることなく、スラリーを濾過して得られる濾過ケーキを常に略一定の含水率にすることができ、更に、この略一定に調整された濾過ケーキを洗浄液によって確実に洗浄することができると共にこの洗浄済の濾過ケーキの含水率を略一定なものとすることができる。
【００７９】
従って、この後に施される乾燥工程において、洗浄済の濾過ケーキ（合成樹脂粒子）の含水率のばらつきに起因した過剰な加熱による合成樹脂粒子の変質や乾燥不足が発生することはなく、洗浄済の濾過ケーキを確実に且つ良好な状態に乾燥して良質な合成樹脂粒子を得ることができる。
【００８０】
しかも、本発明の合成樹脂粒子の洗浄方法では、スラリーの濾過の終了及び濾過ケーキの洗浄の終了を濾過洗浄機から排出された濾過排出液及び洗浄排出液の量によって判断していることから、スラリーの濾過及び濾過ケーキの洗浄が既に終了しているにもかかわらず所定時間が経過するまで放置していたり、或いは、スラリーの濾過及び濾過ケーキの洗浄が未だ終了していないにもかかわらず次の工程に進んでしまうといったことはなく、スラリーの濾過及び濾過ケーキの洗浄を必要最小限の時間で確実に行うことができる。
【００８１】
又、請求項２に記載の合成樹脂粒子の洗浄方法は、請求項１に記載の合成樹脂粒子の洗浄方法において、濾過洗浄機から排出された排出液を排出液貯留槽に貯留し、この排出液が貯留された排出液貯留槽の重量変化によって排出液量を測定していることを特徴とするので、排出液に発生する泡の存在の影響を受けることなく排出液の量を正確に測定することができる。
【００８２】
そして、請求項３に記載の合成樹脂粒子の洗浄方法は、請求項２に記載の合成樹脂粒子の洗浄方法において、排出液貯留槽を複数個、配設し、この排出液貯留槽のうちの一つの排出液貯留槽に濾過洗浄機から排出された排出液を貯留させている間に、残余の排出液貯留槽内の排出液を排出させていることを特徴とするので、大型の排出液貯留槽を用意する必要がなく、しかも、複数個の排出液貯留槽のうちの一つの排出液貯留槽に排出液を貯留している間に、残余の排出液貯留槽に貯留された排出液を排出することにより、複数個の排出液貯留槽によって順次、濾過洗浄機から排出される排出液を連続的に且つ確実に貯留して排出液の量を正確に測定することができる。
【００８３】
最後に、請求項４に記載の合成樹脂粒子の洗浄装置は、水性媒体中に合成樹脂粒子が分散してなるスラリーを濾過する濾過材を備えていると共にこの濾過材により濾過して得られた濾過ケーキを洗浄液により洗浄、脱水する濾過洗浄機と、この濾過洗浄機にスラリータンクからスラリーを一定量供給するスラリー供給制御手段と、上記濾過洗浄機内に洗浄液供給源から洗浄液を一定量供給する洗浄液供給制御手段と、上記濾過洗浄機から排出された排出液の量を測定する排出液量測定手段と、この排出液量測定手段により得られた排出液量に基づいて、上記濾過洗浄機内におけるスラリーの濾過及び濾過ケーキの洗浄の進行を制御する進行制御手段とからなることを特徴とするので、濾過洗浄機の濾過材の目詰まり具合に左右されることなく、スラリーを濾過して得られる濾過ケーキを常に略一定の含水率にすることができ、更に、この略一定に調整された濾過ケーキを洗浄液によって確実に洗浄することができると共にこの洗浄済の濾過ケーキの含水率を略一定なものとすることができる。
【図面の簡単な説明】
【図１】本発明の合成樹脂粒子の洗浄装置を示した模式図である。
【符号の説明】
１ 濾過洗浄機
２ スラリータンク
20a スラリーバルブ
20b スラリー流量計
20c スラリー制御部
31 洗浄液バルブ
32 洗浄液流量計
33 洗浄液制御部
５（51、51）排出液貯留槽
51a 、52a 重量計
６ 排出液量算出部
７ 進行制御部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for washing synthetic resin particles capable of efficiently obtaining synthetic resin particles having a substantially constant water content by filtering and washing a slurry in which synthetic resin particles are dispersed in an aqueous medium, and to use the same. The present invention relates to a synthetic resin particle cleaning apparatus.
[0002]
[Prior art]
Conventionally, as a method for washing synthetic resin particles, a monomer is polymerized in a polymerization vessel by suspension polymerization or emulsion polymerization, and a slurry in which synthetic resin particles are dispersed in an aqueous medium is supplied into a filtration washing machine. After the slurry is filtered to obtain a filter cake, a cleaning solution is supplied to the filter washer to wash the filter cake.
[0003]
Specifically, as the filter washing machine, as shown in Japanese Patent Application Laid-Open No. 10-156219, a machine having a cylindrical filter medium in the machine body is used. The filter cake was obtained by centrifuging the filter cake, and then the washing liquid was supplied to the filter cake to wash the filter cake, and the filter resin was washed from the synthetic resin particles to wash the synthetic resin particles.
[0004]
In the method for washing synthetic resin particles, it is determined that the slurry filtration and the filter cake washing in the filtration washing machine are completed with the passage of a preset time, and the process proceeds to the next step.
[0005]
However, the filter medium of the filter washer has a good liquid permeability immediately after the start of use, so that solid-liquid separation in the process of slurry filtration and filter cake washing is performed smoothly, As the filter material is used more frequently, clogging occurs in the filter material, and the solid-liquid separation rate in the filtration process of the slurry and the filter cake is reduced, and the time required for the filtration of the slurry and the filter cake is filtered. Longer than immediately after the start of use of the material.
[0006]
Therefore, as in the conventional method for washing synthetic resin particles, when the determination of the completion of the filtration of the slurry and the washing of the filter cake in the filtration washing machine is made with the passage of time, the use of the filtration material immediately after the start of use of the filtration material. Even if the solid-liquid separation is smooth and the filtration of the slurry and the washing of the filter cake in the filter washing machine have already been completed, it is not possible to proceed to the next step until a predetermined time elapses. On the other hand, after the filter material has been used many times, the above-mentioned problem occurs in spite of a decrease in the solid-liquid separation rate due to clogging of the filter material, even though a predetermined time has passed. Filtration of the slurry in the filter washing machine and washing of the filter cake are not completed, and there is a problem that the filter cake is not sufficiently washed and the moisture content of the filter cake is high. It was.
[0007]
As described above, when the water content of the synthetic resin particles obtained from the filtration washing machine varies, the synthetic resin particles are excessively dried when the water content is low in the subsequent drying step of the synthetic resin particles. The synthetic resin particles are discolored, and conversely, when the water content is high, there is a further problem that the synthetic resin particles are not sufficiently dried.
[0008]
[Problems to be solved by the invention]
The present invention relates to a method for washing synthetic resin particles, which can efficiently obtain synthetic resin particles having a substantially constant moisture content by filtering and washing a slurry in which synthetic resin particles are dispersed in an aqueous medium. A cleaning apparatus for synthetic resin particles to be used is provided.
[0009]
[Means for solving the problems]
The method for washing synthetic resin particles according to claim 1 is a method in which a certain amount of slurry in which synthetic resin particles are dispersed in an aqueous medium is supplied to a filtration washer for filtration and filtered and discharged from the filtration washer Obtained by filtration of the slurry by supplying a constant amount of washing liquid into the filtration washing machine when the total amount of the measured filtrate discharge liquid amount reached a certain amount when measuring the amount of the discharged fluid. The step of washing the filter cake and measuring the amount of the washing discharged liquid discharged from the filter washing machine, and when the total amount of the measured washing discharge liquid reaches a certain amount, the filter cake of the filter washing machine And a step of stopping the cleaning.
[0010]
Further, the method for cleaning synthetic resin particles according to claim 2 is the method for cleaning synthetic resin particles according to claim 1, wherein the discharged liquid discharged from the filter washer is stored in the discharged liquid storage tank, and this discharged The amount of discharged liquid is measured by the change in weight of the discharged liquid storage tank in which the liquid is stored.
[0011]
The synthetic resin particle cleaning method according to claim 3 is the synthetic resin particle cleaning method according to claim 2, wherein a plurality of drainage liquid storage tanks are arranged, While the discharge liquid discharged from the filtration washing machine is stored in one discharge liquid storage tank, the discharge liquid in the remaining discharge liquid storage tank is discharged.
[0012]
Finally, the apparatus for cleaning synthetic resin particles according to claim 4 is provided with a filter medium for filtering a slurry in which synthetic resin particles are dispersed in an aqueous medium, and is obtained by filtering with the filter medium. A filtration washer for washing the filter cake with the washing liquid, a slurry supply control means for supplying a certain amount of slurry from the slurry tank to the filtration washing machine, and a washing liquid supply control for supplying a certain amount of washing liquid from the washing liquid supply source into the filtration washing machine Means, a discharge amount measuring means for measuring the amount of discharged liquid discharged from the filter washer, and the filtration of the slurry in the filter washer based on the amount of discharged liquid obtained by the discharge amount measuring means. And a progress control means for controlling the progress of the washing of the filter cake.
[0013]
[Action]
The method for washing synthetic resin particles according to the present invention has a clear synthetic resin particle concentration in the filter washer beforehand, that is, a constant amount of slurry having a clear aqueous medium amount is supplied and the filter washer is filtered during filtration of this slurry. The amount of filtered effluent discharged from the water is measured. Then, when the total amount of the filtered discharge liquid reaches a certain amount, the filtration of the slurry is finished, and the process proceeds to the washing step of the filter cake obtained by the filtration of the slurry.
[0014]
That is, the amount of the aqueous medium of the slurry supplied into the filter washer is made constant, and the filtration of the slurry is stopped when the total amount of the filtrate discharged from the filter washer becomes constant. Since the filtration of the slurry is judged by the amount of filtrate discharged without lapse of time, a filter cake having a substantially constant water content can be obtained without being affected by the degree of clogging of the filter material of the filter washer. It can be reliably obtained in a minimum amount of time, and the excess aqueous medium is surely removed, and then the cleaning liquid supplied into the filter washer is contaminated with the aqueous medium, and the filter cake is not sufficiently washed. It does not occur.
[0015]
Next, by supplying a certain amount of washing liquid to the filtration washer, the filter cake having the substantially constant moisture content is washed, and the total amount of washing discharged liquid discharged from the filter washing machine becomes a certain amount. At this point, the washing of the slurry is stopped, and the washing of the slurry is judged by the amount of washing discharged liquid over time, so it is affected by the degree of clogging of the filtering material of the filtration washing machine. And a washed filter cake having a substantially constant water content can be reliably obtained in a minimum amount of time.
[0016]
Thus, according to the method for washing synthetic resin particles of the present invention, a filter cake having a substantially constant moisture content, that is, a substantially constant moisture content, without being affected by the degree of clogging of the filter material of the filtration washer. Synthetic resin particles having a high rate can be obtained, and the subsequent synthetic resin particles can be dried smoothly and reliably to obtain high-quality synthetic resin particles.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An example of the synthetic resin particle cleaning apparatus of the present invention will be described with reference to the drawings. As the filter washer 1 in the synthetic resin particle cleaning apparatus, a conventionally used filter washer is used. For example, a filter medium is stretched horizontally in the filter washer main body, A filter / washer of the type that separates the slurry or filter cake of the slurry or filter cake with a filter medium, or a cylindrical filter medium that can rotate at high speed in the filter washer body, and the slurry or filter cake in the cylindrical filter medium And a centrifugal filter washer that performs solid-liquid separation with the filter medium by rotating the cylindrical filter medium at high speed.
[0018]
A slurry tank 2 storing a slurry in which synthetic resin particles are dispersed in an aqueous medium is connected to and communicated with the filtration and washing machine 1 via a slurry supply pipe 20. That is, the filtration washing machine 1 and the slurry tank 2 connect and communicate one end of the slurry supply line 20 to the filtration washing machine 1 and connect the other end of the slurry supply line 20 to the slurry tank 2 and communicate with each other. Are connected and communicated.
[0019]
Furthermore, a slurry valve 20a for closing and opening the slurry supply pipe 20 and a slurry flow meter 20b for measuring the amount of slurry flowing through the slurry supply pipe 20 are interposed in the slurry supply pipe 20. The slurry valve 20a and the slurry flow meter 20b are electrically connected to a slurry control unit 20c that controls opening and closing of the slurry valve 20a based on the slurry flow rate measured by the slurry flow meter 20b. 20a, the slurry flow meter 20b, and the slurry controller 20c constitute slurry supply control means.
[0020]
Instead of the slurry flow meter 20b, a liquid meter for detecting the amount of slurry in the slurry tank 2 may be disposed in the slurry tank 2.
[0021]
Further, a cleaning liquid supply source (not shown) for supplying a cleaning liquid for cleaning the filter cake is connected to and communicated with the filtration cleaning machine 1 via a cleaning liquid supply pipe 3. That is, the filtration cleaning machine 1 and the cleaning liquid supply source connect and communicate one end of the cleaning liquid supply line 3 to the filtration cleaning machine 1 and connect the other end of the cleaning liquid supply line 3 to the cleaning liquid supply source. Are connected and communicated.
[0022]
Further, the cleaning liquid supply pipe 3 is provided with a cleaning liquid valve 31 for closing the cleaning liquid supply pipe 3 so as to be freely opened and closed, and a cleaning liquid flow meter 32 for measuring the amount of the cleaning liquid flowing through the cleaning liquid supply pipe 3. The cleaning liquid valve 31 and the cleaning liquid flow meter 32 are electrically connected to a cleaning liquid control unit 33 that controls opening and closing of the cleaning liquid valve 31 based on the cleaning liquid flow rate measured by the cleaning liquid flow meter 32. 31, the cleaning liquid flow meter 32 and the cleaning liquid control unit 33 constitute a cleaning liquid supply control means.
[0023]
The washing filter 1 includes a plurality of drainage storage tanks 5 (51, 52...) For temporarily storing the drainage discharged from the washing filter 1 as drainage discharge lines. 4 are connected and communicated with each other.
[0024]
That is, the filtration washing machine 1 and the plurality of drainage storage tanks 5 connect and communicate with one end of the drainage discharge pipe 4 to the filtration washing machine 1 and the other end of the drainage discharge pipe 4. Are connected to and communicated with each of the drainage storage tanks 51, 52... By branching as many as the number of the drainage storage tanks 5. Yes.
[0025]
In the branch portion of the discharge liquid discharge pipe 4, only one of the plurality of branch pipes 41, 42... Is opened and all the remaining branch pipes are opened. An opening / closing valve 4a for closing is interposed. The on-off valve 4a can also close all the branch pipes 41, 42.
[0026]
In addition, the total weight of the drainage storage tanks 51, 52,... Including the drainage liquid stored in the drainage storage tanks 51, 52,. Are provided with weighing scales 51a, 52a.
[0027]
The drainage liquid storage tanks 51, 52..., The drainage liquid storage tank weights 51a, 52a. The drainage liquid amount calculation unit 6 is based on the weight of each of the drainage liquid storage tanks 51, 52... Measured by the weighing scales 51a, 52a. The total weight of the filtered discharge amount discharged during the slurry filtration process and the total weight of the washing discharge amount discharged during the filter cake cleaning process are calculated, and the opening / closing direction of the opening / closing valve 4a is controlled.
[0028]
The drainage liquid storage tank 5 (51, 52...), The weigh scales 51a, 52a..., The opening / closing valve 4a, and the drainage liquid amount calculation unit 6 constitute a drainage liquid amount measuring means. Further, the discharge liquid storage tank 5 may be one and the opening / closing valve 4a may be omitted.
[0029]
Further, the slurry control unit 20c, the cleaning liquid control unit 33, and the discharged liquid amount calculation unit 6 control the progress of the filtration of the slurry in the filtration washing machine 1 and the washing of the filter cake obtained by the filtration of the slurry. It is electrically connected to a progress control unit 7 which is a progress control means.
[0030]
That is, the progress control unit 7 electrically receives the slurry amount from the slurry control unit 20c, the cleaning liquid amount from the cleaning liquid control unit 33, and the discharged liquid amount from the discharged liquid amount calculating unit 6, and based on this information, The progress of slurry filtration and filter cake washing in the filter washer 1 is controlled.
[0031]
Next, the procedure for obtaining a washed filter cake having a substantially constant water content from the slurry, that is, synthetic resin particles, using the synthetic resin particle washing apparatus will be described. First, a slurry obtained by dispersing synthetic resin particles in an aqueous medium is stored in the slurry tank 2. Note that the concentration of the synthetic resin particles in the slurry, that is, the amount of the aqueous medium is clear in advance.
[0032]
An electric signal is sent from the progress control unit 7 to the slurry valve 20a via the slurry control unit 20c to open the slurry valve 20a, and the slurry in the slurry tank 2 is connected to the filtration washer 1 via the slurry supply line 20. Start feeding slurry.
[0033]
At this time, the amount of slurry flowing through the slurry supply pipe 20 is measured by the slurry flow meter 20b, and the slurry flow rate measured by the slurry flow meter 20b is sent to the slurry control unit 20c, and the slurry control unit 20c The total weight of the slurry supplied from the tank 2 into the filter washer 1 is calculated, and when the total weight of the slurry reaches a preset amount, an electrical signal is sent from the slurry controller 20c to the slurry valve 20a. The feed slurry valve 20a is closed, and an electrical signal is sent from the slurry control unit 20c to the progress control unit 7.
[0034]
In the above description, the slurry flow meter 20b is provided in the slurry supply pipe 20, and the amount of slurry is measured by the slurry flow meter 20b. However, the amount of liquid in the slurry tank 2 is not measured by the slurry flow meter 20b. It is also possible to arrange a meter, measure the amount of decrease of the slurry in the slurry tank 2 with this liquid meter, and send the amount of decrease to the slurry control unit 20c. The slurry of a constant weight to be supplied to 1 may be stored, and the slurry of a constant weight may be supplied to the filter washer 1 by supplying all the slurry in the slurry tank 1 to the filter washer 1. That is, in any means, it is sufficient that the slurry in the slurry tank 2 can be supplied to the filtration and washing machine 1 by a predetermined constant weight.
[0035]
Next, in response to an electrical signal from the slurry controller 20c, an electrical signal is emitted from the progress controller 7 to the filtration washer 1. Within the filtration washer 1, the filter is disposed in the filtration washer 1. The slurry is filtered by the filter medium, and the filtration washing machine 1 discharges the filtered discharge liquid along with the filtration of the slurry. The filtered discharge liquid passes through the discharge liquid discharge pipe 4. It is stored in any one of the plurality of discharge liquid storage tanks 5 (for example, the discharge liquid storage tank 51). In the following description, first, it is assumed that the waste liquid storage tank 51 stores the liquid.
[0036]
It should be noted that the discharged liquid amount calculation unit 6 controls which of the plurality of discharged liquid storage tanks 5 (51, 52...) Stores the discharged liquid. The discharge amount calculator 6 controls the open / close valve 4a to open only one of the plurality of branch pipes 41, 42..., While opening the remaining branch pipes. All are closed and the drainage is stored in a drainage reservoir connected to and communicated with the opened branch pipe.
[0037]
As the filtered effluent is stored in the effluent storage tank 51, the weight of the effluent storage tank 51 containing the filtered effluent changes (becomes heavy). This change in weight is measured by a weight meter 51a. Based on the weight change measured by the weigh scale 51a, the discharged liquid amount calculation unit 6 calculates and stores the total weight of the filtered discharged liquid stored in the discharged liquid storage tank 51.
[0038]
On the other hand, the weight capable of storing the effluent in each effluent storage tank 5 (51, 52...) Is smaller than the total weight of the filtered effluent. Therefore, as the filtered effluent is stored in the effluent storage tank 51, the amount of filtered effluent stored in the effluent storage tank 51 reaches an allowable weight.
[0039]
At that time, an electric signal is sent from the discharge liquid amount calculation unit 6 to the open / close valve 4a, and at the same time the branch pipe 41 connected and connected to the discharge liquid storage tank 51 is closed by the open / close valve 4a. For example, only the branch pipe 42 is opened by the open / close valve 4a, and the filtered and discharged liquid is continuously stored in the drain liquid storage tank 52 connected to and in communication with the branch pipe 42.
[0040]
Similarly, as the filtered effluent is stored in the effluent storage tank 52, the weight of the effluent storage tank 52 containing the filtered effluent changes (becomes heavy), and this change in weight is measured by the weigh scale 52a. Based on the weight change measured by the weighing scale 52a, the drainage liquid amount calculation unit 6 calculates the total weight of the filtered drainage liquid stored in the drainage liquid storage tank 52, and the drainage liquid storage tank 51 The total weight of the filtered effluent stored in the effluent storage tank 52 is added to the total weight of the filtered effluent stored in step 1, and the total amount of filtered effluent generated from the start of slurry filtration in the filter washer 1 Is accumulated and memorized.
[0041]
On the other hand, while storing the filtered effluent in the effluent storage tank 52, the filtered effluent stored in the effluent storage tank 51 is discharged by an electrical signal from the discharged liquid amount calculation unit 6. . Then, when an allowable weight of filtered effluent is stored in the effluent storage tank 52, the effluent storage tank 52 is filtered in a manner similar to the above, for example, in a effluent storage tank different from the effluent storage tanks 51 and 52. The discharged liquid may be stored, or the filtered discharged liquid may be stored again in the discharged liquid storage tank 51 from which the filtered discharged liquid has been completely discharged.
[0042]
In this way, the filtered effluent is sequentially stored in a plurality of effluent storage tanks 5. For example, when there are two effluent storage tanks 5, the effluent storage tank 51 and the effluent storage tank 52 are alternately arranged. The total weight of the filtered effluent stored in the effluent storage tank 5, that is, the filtration discharged from the filter washer 1 generated during the filtration of the slurry in the filter washer 1. The total weight of the discharged liquid is accumulated and stored in the discharged liquid amount calculation unit 6.
[0043]
On the other hand, the discharge liquid amount calculation unit 6 is preset with a weight slightly less than the total weight of the aqueous medium of the slurry supplied to the filter washer 1 as the filtration end weight. When the total accumulated weight of the filtered effluent reaches the above filtration end weight, an electric signal is sent from the effluent amount calculating section 6 to the progress control section 7, and the filtration of the slurry in the filter washer 1 is stopped. Is done.
[0044]
As described above, the weight of the aqueous medium in the slurry supplied into the filter washer 1 is set to a constant amount, and the total weight of the filtered discharge liquid generated in the filtration process of the slurry in the filter washer 1 is constant. Since the filtration of the slurry is stopped at the point of time, the water content of the filter cake obtained by filtering the slurry is always substantially constant regardless of the degree of clogging of the filter medium of the filter washer 1 In addition, at the same time as the filtration of the slurry is completed, the filtration of the slurry in the filter washing machine 1 is stopped and the process can proceed to the washing of the next filter cake, so that the slurry can be filtered in a time efficient manner.
[0045]
Moreover, since the amount of the aqueous medium contained in the filter cake is limited to a certain amount, the cleaning liquid supplied in the subsequent cleaning process of the filter cake is mixed with the aqueous medium and the cleaning ability of the cleaning liquid is reduced. The filter cake can be reliably washed with the washing liquid.
[0046]
Next, an electric signal is sent from the progress control unit 7 to the cleaning liquid control unit 33, and the cleaning liquid control unit 33 opens the cleaning liquid valve 31 so that the cleaning liquid is supplied from the cleaning liquid supply source into the filtration cleaning machine 1. The
[0047]
When cleaning of the filter cake with the cleaning liquid is started in the filter cleaning machine 1, the filter cake is cleaned with the cleaning liquid in the filter cleaning machine 1, and the cleaning liquid that has cleaned the filter cake is filtered by the filter medium. The separated and separated washing liquid is discharged from the filtration washing machine 1 as a filtered discharge liquid, and this cleaning discharge liquid is passed through the discharge liquid discharge pipe 4 and is stored in any one of the plurality of discharge liquid storage tanks 5. It is stored in one discharge liquid storage tank, for example, the discharge liquid storage tank that stores the filtered discharge liquid at the end of the filtration process of the filter washer 1 or another discharge liquid storage tank. Below, the waste liquid storage tank which stored the filtrate discharge liquid at the time of completion | finish of the filtration process of the said filtration washing machine 1 is used as it is, and this waste liquid storage tank is used as the waste liquid storage tank 51, for example.
[0048]
During the cleaning of the filter cake in the filter washer 1, the cleaning liquid is supplied from the cleaning liquid supply source into the filter washer 1 through the cleaning liquid supply line 3. The amount of the cleaning liquid supplied into the filtration washing machine 1 is measured by a washing liquid flow meter 32 interposed in the washing liquid supply line 3 from the start of washing of the filter cake in the filtration washing machine 1. The amount of the cleaning liquid measured by the cleaning liquid flow meter 32 is sent to the cleaning liquid control unit 33, and the total weight of the cleaning liquid supplied into the filtration cleaning machine 1 is calculated by the cleaning liquid control unit 33, and the total weight of the cleaning liquid is set in advance. When the amount reached is reached, an electric signal is sent from the cleaning liquid control unit 33 to the cleaning liquid valve 31 to close the cleaning liquid valve 31, and the supply of the cleaning liquid to the filtration cleaning machine 1 is stopped.
[0049]
When supplying the cleaning liquid from the cleaning liquid supply source into the filtered cleaning machine 1, the cleaning liquid may be continuously supplied into the filtered cleaning machine 1 at a constant flow rate or a variable flow rate. The washing liquid may be intermittently supplied into the filtration washing machine 1 with a variable flow rate, that is, the filtration washing machine so as not to hinder the washing of the filter cake in the filtration washing machine 1. It is only necessary to supply a constant weight of the cleaning liquid continuously or intermittently in the inside.
[0050]
Thus, as the washing effluent is stored in the effluent storage tank 51, the weight of the effluent storage tank 51 including the filtered effluent and the cleaning effluent changes. This change in weight is measured by the weigh scale 51a. Based on the weight change measured by the weighing scale 51a, the discharged liquid amount calculation unit 6 calculates and stores the total weight of only the cleaning discharged liquid stored in the discharged liquid storage tank 51. That is, the discharged liquid amount calculation unit 6 stores the weight of the filtered discharged liquid already stored in the discharged liquid storage tank 51 at the time when the filtration of the slurry in the filter washer 1 is completed. By subtracting the weight of the filtered effluent from the weight change measured by the weigh scale 51, the total weight of only the cleaning effluent stored in the effluent storage tank 51 is calculated and stored.
[0051]
On the other hand, the weight capable of storing the effluent in each of the effluent storage tanks 5 (51, 52...) Is smaller than the total weight of the cleaning effluent as in the case of the filtered effluent. Accordingly, as in the case of measuring the total weight of the filtered discharge liquid, the cleaning discharge liquid is sequentially stored in a plurality of discharge liquid storage tanks 5, for example, when there are two discharge liquid storage tanks 5. The total weight of the cleaning effluent stored in these effluent storage tanks 5 (51, 52...) While storing the cleaning effluent alternately in the effluent storage tank 51 and the effluent storage tank 52. That is, the total amount of the washing drainage discharged from the filtration washer 1 generated in the filtration cake washing process in the filtration washer 1 is accumulated and stored in the drainage liquid amount calculation unit 6.
[0052]
In addition, the weight of the washing drainage liquid is set in the drainage liquid amount calculation unit 6 in advance so that the water content of the filtered cake after the washing becomes the target value as the washing end weight. When the accumulated total weight of the washed drainage liquid reaches the washing end weight, an electrical signal is sent from the drainage liquid amount calculation unit 6 to the progress control unit 7, and the electrical signal from the drainage liquid amount calculation unit 6 In response, the progress control unit 7 stops the filtration washing machine 1 to stop washing the filter cake, and a washed filter cake having a substantially constant water content, that is, synthetic resin particles can be obtained. .
[0053]
The filter cake washing in the filter washer 1 is a so-called filter cake dehydration step mainly for further removal of the washing liquid contained in the filter cake after the washing with the washing liquid of the filter cake is almost completed. That is, all the drainage discharged from the filter washer 1 from the start of cleaning of the filter cake of the filter washer 1 to the stop of the filter washer 1 is used as a washing drain solution.
[0054]
As described above, the weight of the cleaning liquid supplied into the filtration and washing machine 1 is set to a constant amount, and the total weight of the washing discharge liquid generated in the process of washing the filter cake in the filtration and washing machine 1 reaches a certain amount. Since the washing of the filter cake is stopped at that time, the filter cake obtained by washing the filter cake, that is, the moisture content of the synthetic resin particles, regardless of the degree of clogging of the filter material of the filter washing machine 1 Is always substantially constant, and at the same time the washing of the filter cake is completed, the washing of the filter cake in the filter washing machine 1 is stopped, so that it is not necessary to spend time unnecessarily to wash the filter cake. The washing cake can be washed well to obtain synthetic resin particles.
[0055]
【Example】
Example 1
The synthetic resin particle cleaning apparatus shown in FIG. 1 was used. However, the other end of the discharge liquid discharge pipe 4 is branched and formed into two branch pipes 41 and 42, the drain liquid storage tank 51 is provided in the branch pipe 41, and the total drain liquid storage 52 is provided in the branch pipe 42. It was configured to be connected and communicated.
[0056]
First, a slurry (polymethyl methacrylate particle concentration: 30% by weight) obtained by dispersing polymethyl methacrylate particles having an average particle diameter of 5 μm in an aqueous medium is obtained in the slurry tank 2. 400 kg was stored.
[0057]
Then, an electric signal is sent from the progress control unit 7 to the slurry valve 20a via the slurry control unit 20c to open the slurry valve 20a, and the slurry tank 2 is connected to the filter washer 1 via the slurry supply line 20. The slurry supply was started.
[0058]
At this time, the amount of slurry flowing through the slurry supply pipe 20 is measured by the slurry flow meter 20b, and the slurry flow rate measured by the slurry flow meter 20b is sent to the slurry control unit 20c, and the slurry control unit 20c The total weight of the slurry supplied from the tank 2 into the filter washer 1 is calculated, and when the total weight of the slurry reaches a preset amount, that is, 300 kg, the slurry controller 20c to the slurry valve 20a. The slurry valve 20a was closed and an electrical signal was sent from the slurry control unit 20c to the progress control unit 7.
[0059]
Next, in response to the electrical signal from the slurry controller 20c, the progress controller 7 issues an electrical signal to the filter washer 1 to increase the pressure in the filter washer 1 to 0.5 MPa, The slurry is filtered by the filter medium of the filter washer 1, and the filtered discharge liquid is discharged from the filter washer 1 along with the filtration of the slurry, and this filtered discharge liquid is discharged to the discharge liquid discharge line 4. And stored in the effluent storage tank 51. In addition, the open / close valve 4a was previously controlled by the discharge liquid amount calculation unit 6 to be connected to and connected to the discharge liquid storage tank 51, and the branch pipe 41 communicated was opened, while the branch pipe 42 was closed.
[0060]
Then, a change in the weight of the drainage liquid storage tank 51 is measured by a weight meter 51a. Based on the weight change measured by the weightmeter 51a, the drainage liquid amount calculation unit 6 stores the change in the drainage liquid storage tank 51. The total weight of the filtered effluent was calculated and stored.
[0061]
Further, while the filtered effluent is stored in the effluent storage tank 51, when the total weight of the filtered effluent stored in the effluent storage tank 51 reaches 20 kg, the effluent amount calculation unit 6 sends an electrical signal to the opening / closing valve 4a, and the branching pipe 41 connected to and communicating with the drainage storage tank 51 is closed by the opening / closing valve 4a, and at the same time the branching pipe 42 is opened by the opening / closing valve 4a. Then, the filtered effluent was continuously stored in the effluent storage tank 52 connected to and communicated with the branch pipe 42.
[0062]
Similarly, a change in the weight of the drainage liquid storage tank 52 is measured by a weight meter 52a. Based on the weight change measured by the weightmeter 52a, the drainage liquid amount calculation unit 6 stores the change in the drainage liquid storage tank 52. The total weight of the filtered effluent is calculated, and the total weight of the filtered effluent stored in the effluent storage tank 52 is added to the total weight of the filtered effluent stored in the effluent storage tank 51. The total weight of all filtered effluents generated from the start of slurry filtration in machine 1 was accumulated and stored.
[0063]
On the other hand, the filtered effluent stored in the effluent storage tank 51 was discharged while the effluent storage tank 52 was storing the filtered effluent. Then, when 20 kg of filtered effluent is stored in the effluent storage tank 52 again, the filtered effluent is again returned to the effluent storage tank 51 from which the filtered effluent has been completely discharged in the same manner as described above. Was stored.
[0064]
The above procedure is repeated, that is, while the filtrate drainage is alternately stored in the drainage reservoir 51 and the drainage reservoir 52, the total weight of the filtrate drainage stored in these drainage reservoirs 51, 52, that is, The total weight of the filtered effluent discharged from the filter washer 1 generated during the filtration of the slurry by the filter washer 1 was accumulated and stored in the discharged liquid amount calculation unit 6.
[0065]
On the other hand, 150 kg is set in advance as the filtration end weight in the discharge liquid amount calculation unit 6, and when the total accumulated weight of the filtered discharge liquid accumulated in the discharge liquid amount calculation unit 6 reaches 150 kg which is the above filtration end weight, An electric signal was sent from the discharged liquid amount calculation unit 6 to the progress control unit 7 to stop slurry filtration in the filter washer 1. At this time, the filtered effluent was stored in the effluent storage tank 52. The water content of the filter cake obtained by filtering the slurry was 40% by weight.
[0066]
Next, an electric signal was sent from the progress control unit 7 to the cleaning liquid control unit 33, and the cleaning liquid control unit 33 opened the cleaning liquid valve 31 to supply the cleaning liquid from the cleaning liquid supply source into the filtration cleaning machine 1.
[0067]
Then, the filter washing machine 1 starts washing with the washing liquid of the filter cake, and the filter cake is washed with the washing liquid, and the washing liquid with which the filter cake is washed is separated by filtration with a filter medium. Then, it was discharged from the filter washer 1 as a filtered discharge liquid and stored in the discharge liquid storage tank 52 through the discharge liquid discharge pipe 4.
[0068]
During the cleaning of the filter cake in the filter washer 1, the cleaning liquid was continuously supplied into the filter washer 1 from the cleaning liquid supply source via the cleaning liquid supply line 3. Then, the amount of the cleaning liquid supplied into the filtration washing machine 1 is measured by the washing liquid flow meter 32 interposed in the washing liquid supply line 3 from the start of washing the filter cake in the filtration washing machine 1, The amount of the cleaning liquid measured by the cleaning liquid flow meter 32 is sent to the cleaning liquid control unit 33, and the total weight of the cleaning liquid supplied into the filtration cleaning machine 1 is calculated by the cleaning liquid control unit 33, and the total weight of the cleaning liquid is set in advance. When the amount reached 800 kg, an electric signal was sent from the cleaning liquid control unit 33 to the cleaning liquid valve 31 to close the cleaning liquid valve 31, and the supply of the cleaning liquid to the filtration cleaning machine 1 was stopped.
[0069]
Further, a change in the weight of the drainage liquid storage tank 52 is measured by a weight meter 52a. Based on the weight change measured by the weightmeter 52a, the drainage liquid amount calculation unit 6 stores the change in the drainage liquid storage tank 52. The total weight of only the washed effluent was calculated and stored. That is, the discharged liquid amount calculation unit 6 stores the weight of the filtered discharged liquid already stored in the discharged liquid storage tank 52 when the filtration of the slurry in the filter washer 1 is completed, By subtracting the weight of the filtered effluent from the weight change measured by the weigh scale 52a, the total weight of only the cleaning effluent stored in the effluent storage tank 52 was calculated and stored.
[0070]
Then, the cleaning drainage is further stored in the drainage storage tank 52, and when the weight of the drainage stored in the drainage storage tank 52 reaches 20 kg, the opening / closing valve 4a The branch line 42 connected to and communicating with the drainage storage tank 52 is closed by the opening / closing valve 4a, and at the same time the branch line 41 is opened by the opening / closing valve 4a. The washing effluent was continuously stored in the effluent storage tank 51 connected to and communicated with 41.
[0071]
Similarly, a change in the weight of the drainage liquid storage tank 51 is measured by a weight meter 51a. Based on the weight change measured by the weightmeter 51a, the drainage liquid amount calculation unit 6 stores the change in the drainage liquid storage tank 51. The total weight of the washed effluent is calculated, and the total weight of the washed effluent stored in the effluent storage tank 51 is added to the total weight of the washed effluent stored in the effluent storage tank 52. The total weight of all washing effluents generated from the start of washing the filter cake in the machine 1 was accumulated and stored.
[0072]
On the other hand, all of the effluent stored in the effluent storage tank 52 was discharged while the effluent storage tank 51 was storing the cleaning effluent. Then, when 20 kg of the cleaning effluent is also stored in the effluent storage tank 51, the cleaning effluent is again returned to the effluent storage tank 52 from which the cleaning effluent has been completely discharged in the same manner as described above. Was stored.
[0073]
The above procedure is repeated, that is, while the filtrate drainage is alternately stored in the drainage reservoir 51 and the drainage reservoir 52, the total weight of the filtrate drainage stored in these drainage reservoirs 51, 52, that is, The total weight of the cleaning effluent discharged from the filtration washer 1 generated in the process of washing the slurry in the filtration washer 1 was accumulated and stored in the discharged liquid amount calculation unit 6.
[0074]
Then, when the total accumulated weight of the cleaning liquid accumulated in the draining liquid amount calculation unit 6 reaches the cleaning end weight, that is, 830 kg, an electric signal is sent from the draining liquid amount calculation unit 6 to the progress control unit 7. In response to the electrical signal from the discharged liquid amount calculation unit 6, the progress control unit 7 stops the filtration washing machine 1 to stop the washing of the filter cake. Resin particles were obtained.
[0075]
In addition, the filter medium of the said filtration washing machine 1 used a new article, and then, without replacing the filter medium, the above procedure was repeated 29 times to obtain 29 washed filter cakes, that is, synthetic resin particles.
(Comparative Example 1)
As a synthetic resin particle cleaning device, the synthetic resin particle cleaning device is the same as in Example 1 except that the open / close valve 4a and the discharge liquid storage tanks 51 and 52 are not provided at the other end of the discharge liquid discharge pipe 4. The filtration of the slurry by the filtration washer 1 was completed in 15 minutes from the start of filtration of the slurry, and the washing of the filter cake was stopped 30 minutes after the supply of 800 kg of washing liquid to the filtration washer 1 was completed. A washed filter cake, that is, synthetic resin particles, was obtained in the same manner as in Example 1 except that the amount of discharged liquid was not measured.
[0076]
The washed filter cake obtained as described above was peeled off from the filter medium and uniformly stirred and mixed, and then 10 g of the filter cake was measured for moisture content using an infrared moisture meter. Table 1 shows the moisture content of the filter cake obtained by the 30th synthetic resin particle washing operation.
[0077]
[Table 1]

[0078]
【The invention's effect】
The method for washing synthetic resin particles according to the present invention is a method in which a fixed amount of slurry in which synthetic resin particles are dispersed in an aqueous medium is supplied to a filtration washing machine for filtration and filtered and discharged from the filtration washing machine. And when the total amount of the measured filtrate discharge amount reaches a certain amount, the filter cake obtained by filtering the slurry is supplied by supplying a certain amount of the washing solution into the filtration washing machine. The step of measuring the amount of washing drainage discharged from the filter washer and the washing of the filter cake by the filter washer is stopped when the total amount of the measured washing drainage reaches a certain amount. Therefore, the filter cake obtained by filtering the slurry can always have a substantially constant water content without being affected by the degree of clogging of the filter medium of the filter washer. It can, furthermore, can be a water content of the washed filter cake substantially constant ones with the filter cake which is adjusted to the substantially constant can be reliably cleaned by the cleaning liquid.
[0079]
Therefore, in the subsequent drying step, the synthetic resin particles are not deteriorated or insufficiently dried due to excessive heating due to variations in the moisture content of the washed filter cake (synthetic resin particles). The filter cake can be surely dried in a good state to obtain good quality synthetic resin particles.
[0080]
Moreover, in the method for washing synthetic resin particles of the present invention, the end of filtration of the slurry and the end of washing of the filter cake are determined based on the amount of the filtered discharge liquid and the washed discharge liquid discharged from the filter washer. The slurry filtration and the filter cake washing have been finished, but it has been left until a predetermined time has passed, or the slurry filtration and the filter cake washing have not been finished yet. Thus, the slurry can be filtered and the filter cake can be reliably washed in the minimum necessary time.
[0081]
Further, the method for cleaning synthetic resin particles according to claim 2 is the method for cleaning synthetic resin particles according to claim 1, wherein the discharged liquid discharged from the filter washer is stored in the discharged liquid storage tank, and this discharged Since the amount of discharged liquid is measured by changing the weight of the discharged liquid storage tank in which the liquid is stored, the amount of discharged liquid can be accurately measured without being affected by the presence of bubbles generated in the discharged liquid. can do.
[0082]
The synthetic resin particle cleaning method according to claim 3 is the synthetic resin particle cleaning method according to claim 2, wherein a plurality of drainage liquid storage tanks are arranged, While the waste liquid discharged from the filter washer is stored in one drain liquid storage tank, the waste liquid in the remaining drain liquid storage tank is discharged, so a large drain liquid There is no need to prepare a storage tank, and the waste liquid stored in the remaining waste liquid storage tank while the waste liquid is stored in one of the plurality of waste liquid storage tanks. By discharging the effluent, it is possible to store the effluent discharged from the filtration washer sequentially and reliably by the plurality of effluent storage tanks, and to accurately measure the amount of the effluent.
[0083]
Finally, the apparatus for cleaning synthetic resin particles according to claim 4 is provided with a filter medium for filtering a slurry in which synthetic resin particles are dispersed in an aqueous medium, and is obtained by filtering with the filter medium. A filter washer for washing and dewatering the filter cake with the washing liquid, a slurry supply control means for supplying a fixed amount of slurry from the slurry tank to the filter washer, and a cleaning liquid for supplying a fixed amount of cleaning liquid from the cleaning liquid supply source into the filter washer Based on the supply control means, the discharged liquid amount measuring means for measuring the amount of discharged liquid discharged from the filter washer, and the discharged liquid amount obtained by the discharged liquid amount measuring means, the slurry in the filter washer It is characterized by comprising a progress control means for controlling the progress of filtration and cleaning of the filter cake, so that it is not affected by the degree of clogging of the filter material of the filter washer The filter cake obtained by filtering the slurry can always have a substantially constant water content, and furthermore, the filter cake adjusted to a substantially constant value can be reliably washed with the washing liquid and the washed filter cake. The water content of can be made substantially constant.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a synthetic resin particle cleaning apparatus of the present invention.
[Explanation of symbols]
1 Filtration washing machine
2 Slurry tank
20a Slurry valve
20b Slurry flow meter
20c Slurry control unit
31 Cleaning fluid valve
32 Cleaning fluid flow meter
33 Cleaning fluid control unit
5 (51, 51) drainage reservoir
51a, 52a Weigh scale
6 Discharged liquid amount calculation part
7 Progress control part

Claims (4)

A step of supplying a certain amount of slurry, in which synthetic resin particles are dispersed in an aqueous medium, to a filter washer for filtration and measuring the amount of filtrate discharged from the filter washer, and the measured filtration When the total amount of the discharged liquid reaches a certain amount, the filter cake obtained by filtering the slurry is washed by supplying a certain amount of the washing liquid into the filter washer and discharged from the filter washer. A synthesis characterized by comprising a step of measuring the amount of washing discharged liquid and a step of stopping washing of the filter cake by the filter washing machine when the total amount of the measured washing discharged liquid reaches a certain amount Cleaning method of resin particles. The effluent discharged from the filtration washer is stored in a effluent storage tank, and the amount of effluent is measured by a change in the weight of the effluent storage tank in which the effluent is stored. A method for washing the described synthetic resin particles. A plurality of waste liquid storage tanks are disposed, and the remaining waste liquid storage tank is stored while the waste liquid discharged from the filtration washing machine is stored in one of the waste liquid storage tanks. The method for cleaning synthetic resin particles according to claim 2, wherein the discharged liquid inside is discharged. A filter washer having a filter medium for filtering a slurry in which synthetic resin particles are dispersed in an aqueous medium and a filter cake obtained by filtering with the filter medium is washed with a washing liquid, and the filter washer A slurry supply control means for supplying a fixed amount of slurry from a slurry tank, a cleaning liquid supply control means for supplying a fixed amount of cleaning liquid from a cleaning liquid supply source into the filtration washing machine, and an amount of discharged liquid discharged from the filtration washing machine And a progress control means for controlling the progress of the filtration of the slurry and the washing of the filter cake in the filter washer based on the amount of the discharged liquid obtained by the discharged liquid amount measuring means. A cleaning apparatus for synthetic resin particles.

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