JP2018164886A - Control method of rotary pressure dehydrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method of a rotary pressure dehydrator capable of suitably controlling a cake moisture content by properly adjusting an electric osmosis power or an inorganic coagulant supply amount when the cake moisture content cannot be well controlled only by adjustment of a restrictor output.SOLUTION: In a rotary pressure dehydrator having an electric osmosis dehydration means, such "adjustment of restrictor output according to PID control" that restrictor output is adjusted to an optimum value calculated based on a deviation between a measured value and a target value of a cake moisture content and the cake moisture content is controlled is executed and, when such a state that the measured value of the cake moisture content is higher than the target value and exceeds a preset upper limit value continues for a definite time or more in the state that the restrictor output is maximum, "stepwise adjustment of electric osmosis power" or "adjustment of electric osmosis power according to PID control" is executed in parallel with " the adjustment of restrictor output according to PID control".SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control method for a rotary pressure dehydrator that performs dehydration by gradually applying pressure to an object to be processed as it advances through an annular (C-shaped) filter chamber formed around a rotation axis.

  A rotary pressure dehydrator is known as one of apparatuses for dehydrating a processing object such as sludge. As shown in Japanese Patent Application Laid-Open No. 2001-113109, a rotary pressure dehydrator introduces a liquid processing object (processing stock solution) into an annular (C-shaped) filter chamber formed around a rotation axis. In this device, the object to be processed is advanced forward by rotating two disk-shaped metal screens (filters), and pressure is gradually applied to perform dehydration.

JP 2001-113109 A JP 2004-074066 A JP 2017-023944 A Japanese Patent No. 6023383

  As a method of controlling the rotary pressurization dehydrator, the method of controlling the inlet pressure by adjusting the screen rotation speed (filter rotation speed), or the displacement of the restrictor (back pressure device) arranged near the cake outlet, that is, A method of controlling the cake moisture content (outlet pressure) by adjusting the restrictor output is known (for example, Japanese Patent Application Laid-Open No. 2004-074066), but when the cake moisture content is too high, The cake moisture content may not be controlled well only by adjusting the restrictor output.

  In recent years, by rotating the osmotic dehydration process by causing electroosmosis to occur in the latter part of the filter chamber, the object to be treated can be dehydrated more efficiently and a dehydrated cake with a lower water content can be obtained. A pressure dehydrator has been developed (for example, Japanese Patent Application Laid-Open No. 2017-023944). In this type of rotary pressure dehydrator, the above-described problems can be solved by appropriately adjusting the electroosmotic power. There is a possibility that it can be solved.

  In addition, when the inorganic flocculant can be supplied at the rear stage of the filter chamber of the rotary pressure dehydrator, the object to be treated can be dehydrated more efficiently, and a dehydrated cake having a lower water content can be obtained. There is a possibility, and in such a rotary pressure dehydrator, the above-described problems may be solved by appropriately adjusting the inorganic flocculant supply amount.

  In the rotary pressurization dehydrator having the electroosmotic dewatering means and / or the flocculant supply means, the electroosmotic power, and / or when the cake moisture content cannot be controlled well only by adjusting the restrictor output. An object of the present invention is to provide a control method for a rotary pressure dehydrator capable of suitably controlling the moisture content of the cake by appropriately adjusting the amount of the inorganic flocculant supplied.

  A control method of a rotary pressure dehydrator according to the present invention includes a rotary shaft, an inner spacer, an outer spacer, a deflector, two metal screens fixed to both side surfaces of the inner spacer, and a control means. The processing object introduced into the annular filter chamber formed between the inner spacer and the deflector and the outer spacer from the stock solution supply port is advanced forward by rotating the two screens, and pressure is gradually applied. In a rotary pressure dehydrator having an electroosmotic dewatering means, a restrictor output having a cake moisture content is arranged. The cake moisture content is controlled by adjusting to the optimum value calculated based on the deviation between the measured value and the target value. When the restrictor output is adjusted and the restrictor output is maximum, the cake moisture content measurement value is higher than the target value and exceeds the preset upper limit value for a certain period of time. When it continues, “stepwise adjustment of electroosmotic power” or “adjustment of electroosmotic power by PID control” is executed in parallel with “adjustment of restrictor output by PID control”.

  In addition, when “stepwise adjustment of electroosmotic power” is executed in this control method, for example, when the restrictor output is maximum, the measured value of the cake moisture content is higher than the target value and is set in advance. Adjustment is made to increase the electroosmotic power by one step when the state exceeding the set upper limit value continues for a certain period of time, and the restrictor output value is within a predetermined reference value or less for a certain period of time. When the above is continued, it is preferable to adjust the electroosmotic power by one step so as to control the cake moisture content.

  In addition, when “adjustment of electroosmotic power by PID control” is executed in this control method, for example, when the restrictor output is maximum, the measured value of the cake moisture content is higher than the target value, When the set upper limit value is exceeded for a certain time or longer, electroosmotic dehydration is started, and the electroosmotic power is a deviation between the measured value of the cake moisture content and the target value, and / or a list. It is preferable that the cake moisture content and / or restrictor output is controlled by adjusting to an optimum value calculated based on the deviation between the restrictor output value and the target value, and in this case, the cake moisture content and / or When the restrictor output value is maintained within a certain range centered on the target value for a certain period of time or longer, electroosmosis dehydration is stopped. It is preferred that once terminated ".

  The control method of the rotary pressure dehydrator according to the present invention includes a rotating shaft, an inner spacer, an outer spacer, a deflector, two metal screens fixed to both side surfaces of the inner spacer, and a control means. The processing object introduced from the stock solution supply port into the annular filter chamber formed between the inner spacer and the deflector and the outer spacer is advanced forward by rotating the two screens, and the pressure is gradually increased. In a rotary pressure dehydrator having a flocculant supply means, a restrictor output is provided with a cake containing water content. The cake moisture content is controlled by adjusting to the optimum value calculated based on the deviation between the measured value of the rate and the target value. `` Adjustment of restrictor output by control '' is executed, and when the restrictor output is maximum, the measured value of cake moisture content is higher than the target value and exceeds the preset upper limit value for a certain period of time When the above is continued, “stepwise adjustment of inorganic flocculant supply amount” or “adjustment of inorganic flocculant supply amount by PID control” is executed in parallel with “adjustment of restrictor output by PID control”. It is characterized by.

  In this control method, when `` stepwise adjustment of the inorganic flocculant supply amount '' is executed, for example, in a state where the restrictor output is maximum, the measured value of the cake moisture content is higher than the target value, When the preset upper limit value is exceeded for a certain period of time, an adjustment is made to increase the inorganic flocculant supply amount by one step, and the restrictor output value is less than or equal to the preset reference value. It is preferable that the moisture content of the cake be controlled by adjusting the amount of the inorganic flocculant to be reduced by one step when the range continues for a certain time or longer.

  Further, when “adjustment of the inorganic flocculant supply amount by PID control” is executed in this control method, for example, when the restrictor output is maximum, the measured value of the cake moisture content is higher than the target value. When the state where the preset upper limit value is exceeded for a certain time or longer, the supply of the inorganic flocculant is started, and the supply amount of the inorganic flocculant is a deviation between the measured value of the cake moisture content and the target value. And / or the cake moisture content and / or restrictor output is preferably controlled by adjusting to an optimal value calculated based on the deviation between the restrictor output value and the target value. When the state where the rate and / or the restrictor output value is maintained within a certain range centered on the target value continues for a certain time or more, the supply of the inorganic flocculant is stopped, and “by PID control It is preferable to temporarily close the adjustment "of the machine flocculant supply.

  The control method of the rotary pressure dehydrator according to the present invention includes a rotating shaft, an inner spacer, an outer spacer, a deflector, two metal screens fixed to both side surfaces of the inner spacer, and a control means. The processing object introduced from the stock solution supply port into the annular filter chamber formed between the inner spacer and the deflector and the outer spacer is advanced forward by rotating the two screens, and the pressure is gradually increased. In the rotary pressure dehydrator having a restrictor whose tip side is displaced in the vertical direction or the horizontal direction is disposed at the cake outlet, and having an electroosmotic dehydrating means and a flocculant supplying means, The restrictor output is adjusted to the optimal value calculated based on the deviation between the measured value of cake moisture content and the target value. When the restrictor output is adjusted by PID control and the restrictor output is maximum, the cake moisture content measurement value is higher than the target value and the preset upper limit value is set. When the excess state continues for a certain time or longer, “stepwise adjustment of electroosmotic power” or “adjustment of electroosmotic power by PID control” is performed in parallel with “adjustment of restrictor output by PID control”. When the electroosmotic electric power reaches a preset upper limit value and the moisture content of the cake cannot be controlled, “stepwise adjustment of the inorganic flocculant supply amount” or “inorganic flocculant by PID control” “Adjustment of supply amount” is executed in parallel with “Stepwise adjustment of electroosmotic power” or “Adjustment of electroosmotic power by PID control” and “Adjustment of restrictor output by PID control”. It is characterized by a door.

  In this control method, when “stepwise adjustment of the inorganic flocculant supply amount” is executed, for example, the electroosmotic power reaches a preset upper limit value, and the cake moisture content cannot be controlled. When the amount of supply of the inorganic flocculant is adjusted, the restrictor output value is maintained within a predetermined reference value or less for a certain period of time. It is preferable that the cake moisture content is controlled by adjusting to reduce by one step.

  Further, when “adjustment of the inorganic flocculant supply amount by PID control” is executed in this control method, for example, the electroosmotic power reaches a preset upper limit value, and the moisture content of the cake cannot be controlled. In this case, the supply of the inorganic flocculant is started, and the amount of the inorganic flocculant supplied becomes the deviation between the measured value of the cake moisture content and the target value and / or the deviation between the restrictor output value and the target value. It is preferable that the cake moisture content and / or restrictor output is controlled by adjusting to the optimum value calculated on the basis of this, and in this case, the cake moisture content and / or restrictor output value is centered on the target value. It is preferable to stop the supply of the inorganic flocculant and to temporarily end “adjustment of the amount of supply of the inorganic flocculant by PID control” when the state maintained within the predetermined range is continued for a predetermined time or longer.

  The control method of the rotary pressure dehydrator according to the present invention includes a rotating shaft, an inner spacer, an outer spacer, a deflector, two metal screens fixed to both side surfaces of the inner spacer, and a control means. The processing object introduced from the stock solution supply port into the annular filter chamber formed between the inner spacer and the deflector and the outer spacer is advanced forward by rotating the two screens, and the pressure is gradually increased. In the rotary pressure dehydrator having a restrictor whose tip side is displaced in the vertical direction or the horizontal direction is disposed at the cake outlet, and having an electroosmotic dehydrating means and a flocculant supplying means, The restrictor output is adjusted to the optimal value calculated based on the deviation between the measured value of cake moisture content and the target value. When the restrictor output is adjusted by PID control and the restrictor output is maximum, the cake moisture content measurement value is higher than the target value and the preset upper limit value is set. When the excess state continues for a certain time or more, “stepwise adjustment of inorganic flocculant supply amount” or “adjustment of inorganic flocculant supply amount by PID control” is “adjustment of restrictor output by PID control”. When the amount of inorganic flocculant supplied reaches a preset upper limit value and the moisture content of the cake cannot be controlled, “stepwise adjustment of electroosmotic power” or “PID control” is performed. "Adjustment of electroosmotic power by means of" Stepwise adjustment of inorganic flocculant supply amount "or" Adjustment of inorganic flocculant supply amount by PID control "and" Adjustment of restrictor output by PID control " It is characterized by being executed.

  In this control method, when “stepwise adjustment of electroosmotic power” is executed, for example, the supply amount of the inorganic flocculant reaches a preset upper limit value, and the cake moisture content cannot be controlled. When the adjustment is made, the electroosmotic power is adjusted to increase by one step, and when the restrictor output value continues for a certain period of time within the range below the preset reference value, the electroosmotic power is decreased by one step. It is preferred that adjustment is made to control the moisture content of the cake.

  Further, when “adjustment of electroosmotic power by PID control” is executed in this control method, for example, the supply of the inorganic flocculant reaches a preset upper limit value and the moisture content of the cake cannot be controlled. Then, electroosmotic dehydration is started, and the electroosmotic power is calculated based on the deviation between the cake moisture content measurement value and the target value and / or the deviation between the restrictor output value and the target value. It is preferable that the cake moisture content and / or restrictor output is controlled by adjusting to an optimum value, and in this case, the cake moisture content and / or restrictor output value is constant around the target value. When the state maintained within the range continues for a certain period of time or more, it is preferable to stop the electroosmotic power and temporarily end “adjustment of electroosmotic power by PID control”.

  In the above control method, the electroosmosis dehydrating means is composed of a metal electrode portion disposed in the rear stage portion of the filter chamber, and a power supply device electrically connected to the electrode portion and the screen. It is preferable that electroosmosis dehydration can be performed in a rotary pressurization dehydrator by applying a DC voltage using an anode and a screen as a cathode. The flocculant supply means includes a flocculant channel that penetrates from the outer peripheral side to the inner peripheral side of the outer spacer and a nozzle disposed at the tip of the flocculant in the rear stage of the filter chamber. It is preferable that it is comprised so that an agent can be supplied.

  Further, in the above control method, the rotary pressure dehydrator has a moisture content meter arranged outside the cake outlet, and information on the measured value of the cake moisture content is acquired by this moisture content meter, or the rotational pressure dehydrator is rotated. The pressure dehydrator has a load cell that measures the main body load acting on the outer spacer, and estimates the moisture content of the cake from the value of the main body load measured by the load cell, and this estimated value is the measured value of the cake moisture content. Or the rotary pressure dehydrator has a pressure sensor arranged inside the cake outlet, and estimates the moisture content of the cake from the outlet pressure value measured by the pressure sensor. It is preferably regarded as a measured value of moisture content.

  According to the control method of the rotary pressure dehydrator according to the present invention, when the cake moisture content cannot be controlled well only by adjusting the restrictor output, the electroosmotic power and / or the inorganic flocculant supply amount is appropriately adjusted. It is possible to return to a state where the moisture content of the cake can be controlled.

FIG. 1 is a diagram showing an internal structure of a rotary pressurization dehydrator 1 to be controlled in the control method of the rotary pressurization dehydrator according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the rotary pressure dehydrator 1 along the line XX shown in FIG. FIG. 3 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the first embodiment of the present invention. FIG. 4 is a flowchart of the control method of the rotary pressure dehydrator 1 according to the second embodiment of the present invention. FIG. 5 is a flowchart of the control method of the rotary pressure dehydrator 1 according to the third embodiment of the present invention. FIG. 6 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the fourth embodiment of the present invention. FIG. 7 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the fifth embodiment of the present invention. FIG. 8 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the sixth embodiment of the present invention. FIG. 9 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the seventh embodiment of the present invention. FIG. 10 is a flowchart of the control method of the rotary pressurization dehydrator 1 according to the ninth embodiment of the present invention. FIG. 11 is a diagram showing an internal structure of another configuration example of the rotary pressure dehydrator 1 that can be controlled in the method of controlling the rotary pressure dehydrator of the present invention. FIG. 12 is a diagram showing an internal structure of another configuration example of the rotary pressure dehydrator 1 that can be controlled in the method of controlling the rotary pressure dehydrator of the present invention. FIG. 13 is a perspective view of the electrode unit 10 shown in FIG. FIG. 14 is a diagram showing an internal structure of another configuration example of the rotary pressure dehydrator 1 that can be controlled in the method of controlling the rotary pressure dehydrator of the present invention.

  Hereinafter, embodiments (first to tenth embodiments) of the present invention “controlling method of a rotary pressurizing dehydrator” will be described.

(First embodiment)
FIG. 1 is a diagram showing an internal structure of a rotary pressurization dehydrator 1 to be controlled in the control method according to the first embodiment of the present invention, and FIG. 1 is a cross-sectional view of a pressure dehydrator 1. FIG.

  The rotary pressure dehydrator 1 supplies a driving force to a rotary shaft 2, an inner spacer 3, an outer spacer 4, a deflector 5, two metal screens 6 (filters), a casing (not shown), and the rotary shaft 2. A cross section formed between the stock solution supply port 7 and the annular (C-shaped) filter chamber 9 (the inner spacer 3 and the deflector 5 and the outer spacer 4). Is a rectangular space, and an object to be treated (in the present embodiment, “sludge”, hereinafter referred to as “sludge”) is introduced into the space from the stock solution supply port 7 to the cake outlet 8. By rotating the rotary shaft 2, the inner spacer 3 (fixed around the rotary shaft 2), and the screen 6 (fixed to both side surfaces of the inner spacer 3). Te sludge was allowed to proceed forward, gradually filtered compressed under pressure, and is configured to be able to discharge the dehydrated cake from the cake outlet 8.

  In the rotary pressure dehydrator 1 of FIG. 1, a vertical restrictor 12 (back pressure device) is disposed at the cake outlet 8. This vertical restrictor 12 is configured such that the tip side is displaced in the vertical direction, and if necessary, the opening area of the cake outlet 8 is reduced, the sludge near the cake outlet 8 is compressed, and it acts on the subsequent sludge. The compression force to be increased can be increased.

  The operation of the vertical restrictor 12 is performed by an air spring device (a cylinder, a piston inserted in the cylinder, a push rod 13 connected to the piston, an electropneumatic converter for supplying compressed air into the cylinder, or the like. Operates the push rod 13 of an air bag, a push rod connected to the outside of the air bag and displaced by inflation / deflation of the air bag, and an electropneumatic converter for supplying compressed air into the air bag) By adjusting the supply amount of compressed air (electro-pneumatic converter output) into the cylinder of the air spring device, the pressing force (restrictor output) and displacement amount of the push rod 13 can be adjusted. It has become.

  Further, a column 16 is attached to the outer spacer 4, and a load cell 17 is attached to the column 16. When the rotary pressure dehydrator 1 is in operation, the rotational force of the inner spacer 3 and the screen 6 is transmitted to the main body (outer spacer 4 and the like) through the sludge introduced into the filter chamber 9. A force (load) for rotating in the same direction also acts on the outer spacer 4 and the like. In this rotary pressure dehydrator 1, the outer spacer 4 and the like are fixed by struts 16 so that they are not rotated by a load, and the main body load load of the rotary pressure dehydrator 1 is provided by a load cell 17 arranged in the middle thereof. Is measured, and the measured value information is transmitted to the control means.

  Furthermore, the rotary pressure dehydrator 1 of FIG. 1 is provided with electroosmotic dehydrating means, and can dehydrate an object more efficiently by dehydrating action by electroosmosis. Specifically, at the rear stage of the filter chamber 9 (the cake outlet 8 side of the intermediate position of the filter chamber 9), an intermediate position in the width direction of the filter chamber 9 (with a gap between each screen 6 on both sides). The plurality of metal electrode portions 10 are arranged in series in the direction of the sludge. These electrode portions 10 are used as anodes and the screen 6 is used as a cathode so that a DC voltage can be applied, so that an electroosmotic phenomenon can be developed in the filter chamber 9 so that dehydration can be performed more efficiently. It has become. However, in the control method of the present embodiment, the electroosmosis is executed only when it becomes difficult to control the target item only by adjusting the restrictor output.

  FIG. 3 is a flowchart of the control method according to the first embodiment of the present invention. The control target item in this control method is the moisture content (cake moisture content) in the dewatered cake discharged from the cake outlet 8, and this control method (FIG. 3) is used when the rotary pressure dehydrator 1 shown in FIG. By performing the “adjustment of restrictor output by PID control” routine shown in (1) and the “stepwise adjustment of electroosmotic power” routine shown in FIG. 3 (2), the moisture content of the cake is Control can be performed so as to approach a preset target value (to converge within a certain range centered on the target value). Hereinafter, each of the two routines will be described in detail.

  First, in the routine of “Adjustment of restrictor output by PID control”, as shown in FIG. 3A, a deviation between the measured value of the cake moisture content and the target value is detected. Information on the measured value of the cake moisture content is acquired by a moisture meter (microwave type, near infrared type, etc.) disposed outside the cake outlet 8 and transmitted to the control means. In addition, since the value of the main body load load measured by the load cell 17 has a “negative correlation” with the cake moisture content value, the cake moisture content value is estimated from the value of the main body load load, and the estimated value is used as the cake moisture content. You may make it consider it as the measured value of a moisture content.

  And based on the deviation between the measured value (or estimated value) of the cake moisture content and the target value, the optimum restrictor output (electropneumatic converter output of the air spring device) to bring the cake moisture content close to the target value is Then, the calculation is performed by the arithmetic processing unit of the control means, and the vertical moisture content of the vertical restrictor 12 is controlled accordingly so that the cake moisture content approaches the target value (PID control).

  For example, when the measured value of the moisture content of the cake increases due to some factor and becomes higher than the target value, the restrictor output is adjusted to increase. As described above, the vertical restrictor 12 (see FIG. 1) is for compressing the sludge near the cake outlet 8 and for increasing the compressive force acting on the subsequent sludge, so that the restrictor output is increased. When adjusted to, the compressive force acting on the sludge increases, and the moisture content of the cake can be reduced. On the other hand, when the measured value of the cake moisture content decreases due to some factor and becomes lower than the target value, the restrictor output is adjusted to be small.

  The routine of “adjustment of restrictor output by PID control” is continuously executed while the rotary pressurization dehydrator 1 is in operation. However, there is a limit to controlling the moisture content of the cake by adjusting the restrictor output. Specifically, when the measured value of the cake moisture content is higher than the target value, the restrictor output is adjusted to increase as described above, and the sludge near the cake outlet 8 and Although the compressive force acting on the subsequent sludge is increased, the cake moisture content is lower than the target value in the state where the restrictor output is maximum (the opening area of the cake outlet 8 is reduced to the minimum). When the high state continues, the restrictor output cannot be increased any more, so the moisture content of the cake cannot be lowered and cannot be brought close to the target value.

  As described above, when the cake moisture content cannot be controlled by adjusting the restrictor output, the control method according to the present embodiment outputs electric power to the electrode unit 10 and the screen 6 to perform electroosmosis. This is achieved by adjusting the output stepwise (execution of the routine of “stepwise adjustment of electroosmotic power” shown in FIG. 3B). (While the routine of “stepwise adjustment of electroosmotic power” is being executed, the routine of “adjustment of restrictor output by PID control” shown in FIG. 3A is continuously executed. .)

  Specifically, in a state where the restrictor output is maximum, a state where the measured value of the cake moisture content is higher than the target value and exceeds a preset upper limit value (for example, “target value + 10%”). When it is detected by the control means that it has continued for a certain time (for example, “3 minutes”) (satisfaction of “electroosmosis start condition”), as shown in FIG. Adjustment is performed to increase the output power by one step (“10 kW” in the present embodiment). In other words, when electroosmosis has not been performed before the adjustment, it is increased from “0 kw” to “10 kw”, and when the power of “10 kw” is output before the adjustment, it is set to “20 kw”. Increased adjustment.

  When an electric osmosis phenomenon is caused in the filter chamber 9 by supplying electric power to the electrode unit 10 or the like, the moisture in the sludge moves toward the screen 6 (cathode), and the moisture in the filter chamber 9 Passes through the eyes of the screen 6 and is discharged outside the filter chamber 9. Further, due to electroosmosis, a repulsive force against the screen 6 acts on the solid content in the vicinity of the screen 6, and clogging of the screen 6 is suppressed. As a result, dehydration can be performed more efficiently, and the moisture content of the cake can be reduced.

  The dewatering performance improved by electroosmosis is basically proportional to the amount of power supplied to the electrode unit 10 and the like. That is, as long as the limit is not exceeded, the moisture content of the cake can be reduced as the electroosmotic power is increased. Therefore, even when the restrictor output is at a maximum and the cake moisture content exceeds the upper limit for a certain period of time, the electroosmotic power does not reach the target value. By performing the increase adjustment or by repeating the increase adjustment as many times as necessary, the moisture content of the cake can be reduced and returned to a controllable state by adjusting the restrictor output.

  However, as the consumed power increases, the running cost increases accordingly, and it does not contribute to the reduction of CO2 emissions. Therefore, it is desirable to keep the electroosmotic power to the minimum necessary. Therefore, in this control method, when electroosmotic dehydration is performed, not only the moisture content of the cake but also the value of the restrictor output is monitored over time, and based on that value (when certain conditions are met) The electroosmotic power can be minimized.

  Specifically, when dehydration by electroosmosis is performed, the output of the restrictor is the optimum calculated based on the deviation between the measured value (or estimated value) of the cake moisture content and the target value as described above. When the cake moisture content is relatively high (PID control), the restrictor operates at a high output (for example, the restrictor output changes in the range of 70 to 100% of the maximum output value). ), When the moisture content of the cake is relatively low, the restrictor operates at a low output (for example, the restrictor output changes within a range of 0 to 30% of the maximum output value).

  And, if the restrictor is operating at high output and the adjustment is made to reduce the electroosmotic power by one step in order to reduce the power consumption, the cake moisture content will again exceed the upper limit value. Even if the restrictor output is adjusted to the maximum value, the moisture content of the cake may not be brought close to the target value. On the other hand, when the restrictor is operating at a low output and the electroosmotic power is adjusted to decrease by one step, the cake moisture content can be controlled by adjusting the restrictor output. There is sex.

  Therefore, in this control method, when electroosmotic dehydration is performed, the restrictor output value adjusted by the control means is equal to or less than a preset reference value (for example, “30% of the maximum output value”). In the case of continuing for a certain time (for example, “3 minutes”) or more in this range, an adjustment is made to decrease the electroosmotic power by one step (“10 kW” in the present embodiment).

  That is, in this control method, when the restrictor is operating at a low output during the execution of the routine for adjusting the electroosmotic power (see FIG. 3 (2)), the restrictor is operated at a higher output. In other words, when the burden on the restrictor is small, adjustment is performed such that the burden on electroosmosis dehydration (that is, power consumption) is reduced by increasing the burden on the restrictor. As a result, the power consumed by electroosmosis can be minimized.

  Thus, according to this control method, the cake moisture content converges within a certain range centered on the target value so that the cake moisture content approaches the preset target value when the rotary pressurization dehydrator 1 is in operation. The power consumed by electroosmosis can be minimized.

(Second Embodiment)
In the first embodiment, the electroosmotic power is adjusted stepwise (increase adjustment or decrease adjustment) depending on the situation, but the electroosmotic power is adjusted by PID control. You can also

  Specifically, during the execution of the “adjustment of restrictor output by PID control” routine shown in FIG. 3 (1), when the restrictor output is maximum, the measured value of the cake moisture content is lower than the target value. It is high and exceeds a preset upper limit value (for example, “target value + 10%”) for a certain period of time (for example, “3 minutes”) or longer (satisfaction of “start condition for electroosmosis”) Is detected by the control means, the electroosmotic dehydration is started. In parallel with “Adjustment of restrictor output by PID control” shown in FIG. 3 (1), “Adjustment of electroosmotic power by PID control” Configure the routine to be executed.

  For example, as shown in FIG. 4, the deviation between the measured value (or estimated value) of the cake moisture content and the target value, and the deviation between the restrictor output value and the target value (for example, “20% of the maximum output value”). Based on this, the electroosmotic power optimal for bringing the cake moisture content and the restrictor output close to the target values, respectively, is calculated by the arithmetic processing unit of the control means, and the electric power is output to the electrode unit 10 and the like accordingly. Perform infiltration. By adjusting the electroosmotic power in this way, the cake moisture content and the restrictor output can be controlled so as to approach the target values, respectively (PID control).

  When the routine for adjusting the electroosmotic power (see FIG. 4) is executed, the cake moisture content and the restrictor output are within a certain range centered on the target value (for example, “target value ± 5 % ”), When the control means detects that the state of being maintained within a certain period of time (for example,“ 3 minutes ”) or more (satisfaction of the electroosmosis termination condition) is detected, The routine of “Adjustment of restrictor output by PID control” shown in FIG. 3 (1) until the routine of “adjustment of electroosmosis power by PID control” is once finished and the above “start condition of electroosmosis” is satisfied again. Configure only to run.

  Even when configured in this manner, the moisture content of the cake approaches the preset target value during operation of the rotary pressurization dehydrator 1 shown in FIG. 1, as in the control method of the first embodiment. It can be controlled (so that it converges within a certain range centered on the target value), and the power consumed by electroosmosis can be minimized.

(Third embodiment)
In the second embodiment described above, the routine of “adjustment of electroosmotic power by PID control” determines the optimal electroosmotic power in consideration of not only the deviation in cake moisture content but also the deviation in restrictor output value. Although calculated and configured to perform electroosmosis (see FIG. 4), as shown in FIG. 5, it is optimal to bring the cake moisture content close to the target value based only on the deviation of the cake moisture content. You may comprise so that electroosmosis power may be calculated and electroosmosis may be performed.

  In this case, “the end of electroosmosis” is “the restrictor output value has continued for a certain period of time (eg“ 3 minutes ”) within a predetermined reference value (eg“ 30% of the maximum output value ”)”. Condition ".

  Also when comprised in this way, like the control method of the said 1st Embodiment and 2nd Embodiment, at the time of operation | movement of the rotary pressurization dehydrator 1 shown in FIG. 1, the cake moisture content is set to the preset target. The power can be controlled so as to approach the value (to converge within a certain range centered on the target value), and the power consumed by electroosmosis can be minimized.

(Fourth embodiment)
In the rotary pressure dehydrator 1 shown in FIG. 1, the flocculant supply means (flocculating agent flow path 14, nozzle 15) is arranged at the rear stage of the filter chamber 9 (the cake outlet 8 side of the intermediate position of the filter chamber 9). The flocculant can be supplied into the filter chamber 9. More specifically, the outer spacer 4 of these rotary pressurization dehydrators 1 is formed with a flocculant flow path 14 penetrating from the outer peripheral side to the inner peripheral side. When the flocculant is fed to the agent flow path 14, the flocculant is released from the nozzle 15 (disposed on the inner peripheral surface of the outer spacer 4) at the tip, and can be supplied into the filter chamber 9.

  When the coagulant supplying means (coagulant flow path 14 and nozzle 15) is arranged at the rear stage of the filter chamber 9 and the inorganic coagulant is supplied into the filter chamber 9, the rotation pressure dehydration is compared with the case of not supplying the coagulant. The dewatering performance of the machine 1 can be improved, and a dehydrated cake with a lower moisture content can be obtained.

  This point will be described in detail. When the sludge is dehydrated, the sludge is usually tempered by addition of a flocculant before being introduced into the rotary pressure dehydrator 1. Specifically, a flocculant is added to sludge in a flocculator (not shown), and mixed and stirred. Examples of the flocculant added in advance to the sludge include a polymer flocculant and an inorganic flocculant (polyiron sulfate, PAC, etc.). When a polymer flocculant is added, sludge particles can be flocked by charge neutralization and crosslinking to form “aggregated sludge”, and solid-liquid separation can be improved. Further, when not only the polymer flocculant but also the inorganic flocculant is used in combination, the solid-liquid separation property of the sludge can be further improved.

  When the coagulated sludge is introduced into the filter chamber 9 of the rotary pressure dehydrator 1, as described above, the sludge is sent forward through the filter chamber 9 by the rotation of the rotary shaft 2, the inner spacer 3, and the screen 6. In the process, dehydration proceeds and the moisture content of the sludge gradually decreases. When the sludge has passed through the front part of the filter chamber 9, dehydration proceeds to some extent, and the moisture content is reduced (solid content concentration is increased) (concentrated sludge).

  Addition of inorganic flocculants such as polysulfate to flocculent sludge (sludge in which sludge particles are flocked by addition of polymer flocculant) causes the water contained in the floc to exude to the outside and release it. can get. When the inorganic flocculant having such an action is added to the concentrated sludge (coagulated sludge) in the latter part of the filter chamber 9, the dewatering efficiency in the latter part of the filter chamber 9 is improved, and the moisture content of the cake is effectively increased. Can be lowered.

  In the control methods of the first to third embodiments, when the cake moisture content cannot be controlled only by adjusting the restrictor output, the electroosmosis dehydration is performed in parallel. However, in the control method of the present embodiment (fourth embodiment), instead of performing electroosmotic dehydration, an inorganic flocculant is supplied at the rear stage of the filter chamber 9 and the supply amount is adjusted stepwise ( The execution of the routine of “stepwise adjustment of the inorganic flocculant supply amount” shown in FIG. (Note that the routine of “adjustment of restrictor output by PID control” shown in FIG. 3 (1) is continuously executed while the routine of “stepwise adjustment of the supply amount of inorganic flocculant” is being executed. )

  Specifically, in a state where the restrictor output is maximum, a state where the measured value of the cake moisture content is higher than the target value and exceeds a preset upper limit value (for example, “target value + 10%”). When it is detected by the control means that it has continued for a certain time (for example, “3 minutes”) or more, as shown in FIG. In the embodiment, “10%”) is increased. That is, when the inorganic flocculant was not supplied before the adjustment, the increase was made from “0%” to “10%”, and “10%” of the inorganic flocculant was supplied before the adjustment. In this case, the increase is adjusted to “20%”.

  When an inorganic flocculant is added to the concentrated sludge that is in the middle of the latter part of the filter chamber 9, as described above, the dehydration efficiency in the latter part of the filter chamber 9 is improved, and the moisture content of the cake can be effectively reduced. And the dehydration performance improved by the supply of the inorganic flocculant to the latter part of the filter chamber 9 is basically proportional to the supply amount of the inorganic flocculant. That is, unless the limit is exceeded, the moisture content of the cake can be reduced as the supply amount is increased. Therefore, even if the restrictor output is maximum and the cake moisture content exceeds the upper limit for a certain period of time and falls into a state where it cannot reach the target value, the inorganic flocculant By performing an increase adjustment of the supply amount or by repeating the increase adjustment as many times as necessary, the cake moisture content can be reduced and returned to a controllable state by adjusting the restrictor output.

  However, since the inorganic flocculant is not cheap, the running cost increases as the supply amount increases. Therefore, it is desirable to keep the amount of inorganic flocculant used to the minimum necessary. Therefore, in this control method, when the inorganic flocculant is supplied, not only the moisture content of the cake but also the value of the restrictor output is monitored over time, and based on that value (when certain conditions are met) ), The amount of the inorganic flocculant used can be minimized.

  Specifically, when the routine of “stepwise adjustment of the inorganic flocculant supply amount” shown in FIG. 6 is being executed, the output of the restrictor is the measured value (or estimated value) of the cake moisture content as described above. When the cake moisture content is relatively high (PID control) and the cake moisture content is relatively high, the cake moisture content is relatively high. If it is low, the restrictor will operate at low power.

  If the restrictor is operating at a high output, and the adjustment is made to reduce the supply amount of the inorganic flocculant by one step in order to reduce the running cost, the moisture content of the cake again exceeds the upper limit. Therefore, even if the restrictor output is adjusted to the maximum value, there is a possibility that the moisture content of the cake cannot be brought close to the target value. On the other hand, when the restrictor is operating at a low output and the adjustment is made to reduce the supply amount of the inorganic flocculant by one step, it is possible to control the cake moisture content by adjusting the restrictor output. There is a possibility that it can be maintained.

  Therefore, in this control method, when the routine of “stepwise adjustment of the inorganic flocculant supply amount” shown in FIG. 6 is executed, the value of the restrictor output adjusted by the control means is set in advance. In the case of continuing for a certain time (for example, “3 minutes”) or more within a range of a reference value (for example, “30% of the maximum output value”) or less, the supply amount of the inorganic flocculant is set to one stage (in the present embodiment, “10”). % ") Is being reduced.

  That is, in this control method, when dehydration is performed by supplying the inorganic flocculant, when the restrictor is operating at a low output, in other words, by operating the restrictor at a higher output, When the burden on the restrictor is small, adjustment is performed such that the burden on the inorganic flocculant (that is, the running cost) is reduced by increasing the burden on the restrictor. As a result, the amount of inorganic flocculant used can be minimized.

  Thus, according to this control method, when the rotary pressurization dehydrator 1 is in operation, the cake moisture content approaches the preset target value (converges within a certain range centered on the target value). The amount of inorganic flocculant used can be minimized.

(Fifth embodiment)
In the fourth embodiment, the supply amount of the inorganic flocculant is adjusted stepwise (increase adjustment or decrease adjustment) depending on the situation, but the supply amount of the inorganic flocculant is controlled by PID control. It can also be configured to be adjusted.

  Specifically, during the execution of the “adjustment of restrictor output by PID control” routine shown in FIG. 3 (1), when the restrictor output is maximum, the measured value of the cake moisture content is lower than the target value. It is high and exceeds a preset upper limit value (for example, “target value + 10%”) for a certain period of time (for example, “3 minutes”) or longer (“starting condition for supplying inorganic flocculant”) When the satisfaction is detected by the control means, the supply of the inorganic flocculant is started. In parallel with the routine of “Adjustment of restrictor output by PID control” shown in FIG. The routine of “adjustment of flocculant supply amount” is executed.

  For example, as shown in FIG. 7, the deviation between the measured value (or estimated value) of the cake moisture content and the target value, and the deviation between the restrictor output value and the target value (for example, “20% of the maximum output value”). Based on this, the optimum amount of the inorganic flocculant supplied to approximate the cake moisture content and the restrictor output to the target values is calculated by the arithmetic processing unit of the control means, and the inorganic flocculant is supplied accordingly to perform dehydration. Run. By adjusting the supply amount of the inorganic flocculant, the cake moisture content and the restrictor output can be controlled so as to approach the target values, respectively (PID control).

  When the routine of “adjustment of inorganic flocculant supply amount by PID control” shown in FIG. 7 is being executed, the cake moisture content and the restrictor output are within a certain range centered on the target value ( For example, in the control means, the state in which each state is maintained within a range of “target value ± 5%” (for example, “satisfaction of the end condition for supplying the inorganic flocculant”) for a certain period of time (for example, “3 minutes”) is satisfied. If detected, the routine of “adjustment of the amount of inorganic flocculant supplied by PID control” is temporarily ended and the above “starting condition for supplying the inorganic flocculant” is satisfied again as shown in FIG. Only the routine of “adjustment of restrictor output by PID control” is executed.

  Even when configured in this manner, the moisture content of the cake approaches the preset target value during operation of the rotary pressurization dehydrator 1 shown in FIG. 1, as in the control method of the fourth embodiment. It can be controlled (so that it converges within a certain range centered on the target value), and the amount of the inorganic flocculant used can be minimized.

(Sixth embodiment)
In the fifth embodiment, the routine of “adjustment of the amount of inorganic flocculant supplied by PID control” is the optimum inorganic agglomeration considering not only the deviation of cake moisture content but also the deviation of restrictor output value. It is configured to calculate the agent supply amount and perform dehydration by supplying the inorganic flocculant (see FIG. 7). As shown in FIG. 8, the cake moisture content is based only on the deviation of the cake moisture content. In order to approximate the target value to the target value, an optimum inorganic flocculant supply amount may be calculated, and dewatering by the inorganic flocculant supply may be performed.

  In this case, “inorganic flocculant supply” means that “the restrictor output value has continued for a certain period of time (eg,“ 3 minutes ”) within a predetermined reference value (eg,“ 30% of the maximum output value ”) or less. End condition ”.

  Also when comprised in this way, like the control method of the said 4th Embodiment and 5th Embodiment, at the time of operation | movement of the rotary pressurization dehydrator 1 shown in FIG. 1, the cake moisture content is set to the preset target. It can be controlled so as to approach the value (so that it converges within a certain range centered on the target value), and the amount of the inorganic flocculant used can be minimized.

(Seventh embodiment)
As described above, the rotary pressure dehydrator 1 shown in FIG. 1 can perform electroosmotic dehydration by supplying electric power to the electrode unit 10 and the like, and supply an inorganic flocculant at the rear stage of the filter chamber 9. However, dehydration can be performed. In the first to third embodiments, when the cake moisture content cannot be controlled only by adjusting the restrictor output, the electroosmotic power is adjusted in parallel with the routine for adjusting the restrictor output. In the fourth to sixth embodiments, the cake is obtained by executing the routine for adjusting the inorganic flocculant supply amount in parallel with the routine for adjusting the restrictor output. It is configured to control the moisture content.

  In the control method of the present embodiment (seventh embodiment), when the cake moisture content cannot be controlled by executing the routine for adjusting the restrictor output and the routine for adjusting the electroosmotic power, in parallel with these. The cake moisture content can be controlled by executing the routine of “stepwise adjustment of the inorganic flocculant supply amount” shown in FIG.

  Specifically, in the same way as in the control method of the first to third embodiments, a routine for adjusting the electroosmotic power (in FIG. 3A) in parallel with the routine for adjusting the restrictor output (see FIG. 3A). When one of the routines shown in FIG. 3 (2), FIG. 4 and FIG. 5 is being executed, the electroosmotic power has already reached a preset upper limit value (for example, “OO kw”), When the control of the moisture content of the cake becomes impossible, an adjustment is made to increase the supply amount of the inorganic flocculant to the rear stage of the filter chamber 9 by one stage (in this embodiment, “10%”).

  As described above, the dewatering performance in the rear part of the filter chamber 9 is the same as in the case where the inorganic flocculant is added to the concentrated sludge in the latter part of the filter chamber 9 and the electroosmosis is performed. It is possible to improve and effectively reduce the moisture content of the cake, but when these are performed simultaneously, that is, when electroosmosis is performed on the concentrated sludge to which the inorganic flocculant has been added, the addition of the inorganic flocculant It is possible to expect an effect (synergistic effect) that is greater than the sum of the dehydrating effect and the dehydrating effect by electroosmosis.

  More specifically, when electroosmosis is performed on the ongoing concentrated sludge through the rear stage of the filter chamber 9, the moisture in the concentrated sludge can be moved toward the screen 6 as described above. Although good dehydration is possible, the only thing that can be transferred by electroosmosis is the water that has already been released in the concentrated sludge (free water) at that time, and is contained in the floc. It is difficult to move the moisture that is contained by electroosmosis.

  In the case where an inorganic flocculant is added to the concentrated sludge in which electroosmosis is performed in the latter part of the filter chamber 9, the moisture contained in the floc can be exuded and newly released. That is, by adding the inorganic flocculant at an appropriate timing, the amount of free water in the concentrated sludge can be increased, and as a result, compared with the case where only one of electroosmosis and inorganic flocculant supply is performed. Thus, more efficient dehydration is possible, and a dehydrated cake having a lower moisture content can be obtained.

  Accordingly, a routine for adjusting the electroosmotic power (one of the routines shown in FIGS. 3 (2), 4 and 5) is executed in parallel with the routine for adjusting the restrictor output (see FIG. 3 (1)). When the restrictor output is maximum, the cake moisture content exceeds the upper limit for a certain period of time, and the electroosmotic power has already reached the preset upper limit. Therefore, even if the power cannot be increased any more and the cake moisture content cannot be brought close to the target value, by adjusting the increase in the supply amount of the inorganic flocculant Alternatively, the cake moisture content can be effectively reduced by repeating the increase adjustment as many times as necessary, and the cake moisture content can be controlled by adjusting the restrictor output and adjusting the electroosmotic power. It can be restored.

  In this control method, the routine of “stepwise adjustment of the inorganic flocculant supply amount” shown in FIG. 9 is used so that the amount of the inorganic flocculant used can be minimized and the running cost can be reduced. Is carried out, the moisture content of the cake is within a certain range centered on the target value (for example, within the range of “target value ± 5%”) or within a certain range (for example, “3 minutes”). “) When the above is continued, adjustment is performed to reduce the supply amount of the inorganic flocculant by one step (“ 10% ”in the present embodiment).

  Thus, according to this control method, when the rotary pressurization dehydrator 1 is in operation, the cake moisture content approaches the preset target value (converges within a certain range centered on the target value). The amount of inorganic flocculant used can be minimized.

(Eighth embodiment)
In the seventh embodiment, the supply amount of the inorganic flocculant is adjusted stepwise (increase adjustment or decrease adjustment) depending on the situation, but the supply amount of the inorganic flocculant is controlled by PID control. It can also be configured to be adjusted.

  Specifically, in parallel with the routine for adjusting the restrictor output (see FIG. 3 (1)), the routine for adjusting the electroosmotic power (one of the routines shown in FIGS. 3 (2), 4 and 5). ) Is executed, the restrictor output is maximum, the cake moisture content measurement value is higher than the target value, and exceeds the preset upper limit (for example, “target value + 10%”) Continues for a certain time (for example, “3 minutes”) and the electroosmotic power has already reached the preset upper limit value, so the power cannot be increased any more, and the cake moisture content When the control means detects that the condition cannot be brought close to the target value (satisfaction of “starting condition of inorganic flocculant supply”), the inorganic flocculant supply is started and the restrictor output is adjusted. Routine (Figure 3 1)), and in parallel with the routine for adjusting electroosmotic power (any of the routines shown in FIGS. 3 (2), 4 and 5), “adjustment of inorganic flocculant supply amount by PID control” The routine (one of the routines shown in FIGS. 7 and 8) is executed.

  When the routine of “adjustment of the amount of inorganic flocculant supplied by PID control” shown in FIG. 7 or FIG. 8 is executed, the cake moisture content and the restrictor output are constant with the target value at the center. Each state maintained within the range (for example, within the range of “target value ± 5%”) has continued for a certain period of time (for example, “3 minutes”) or more (satisfaction of the end condition for supplying the inorganic flocculant). If detected by the control means, the routine of “adjustment of the amount of inorganic flocculant supplied by PID control” is temporarily terminated, and the restrictor output is output until the “condition for starting the supply of inorganic flocculant” is satisfied again. Only the routine to adjust (see FIG. 3 (1)) and the routine to adjust the electroosmotic power (any one of the routines shown in FIG. 3 (2), FIG. 4 and FIG. 5) are executed.

  Even when configured in this manner, as in the control method of the seventh embodiment, during operation of the rotary pressurization dehydrator 1 shown in FIG. 1, the moisture content of the cake approaches the preset target value. It can be controlled (so that it converges within a certain range centered on the target value), and the amount of the inorganic flocculant used can be minimized.

(Ninth embodiment)
In the seventh embodiment and the eighth embodiment, when the cake moisture content cannot be controlled by executing the routine for adjusting the restrictor output and the routine for adjusting the electroosmotic power, in parallel with these, The cake moisture content can be controlled by executing a routine for adjusting the supply amount of the inorganic flocculant. However, in the control method of the present embodiment (the ninth embodiment), the electroosmotic power is adjusted. When the moisture content of the cake cannot be controlled by switching the order of the routine for adjusting the routine and the inorganic flocculant supply amount, and executing the routine for adjusting the restrictor output and the routine for adjusting the inorganic flocculant supply amount, In parallel with these, the routine of “stepwise adjustment of electroosmotic power” shown in FIG. And it is configured to be able to control the moisture content.

  Specifically, the inorganic flocculant supply amount is adjusted in parallel with the routine for adjusting the restrictor output (see FIG. 3 (1)), as in the control methods of the fourth to sixth embodiments. When the routine (one of the routines shown in FIGS. 6, 7, and 8) is being executed, the inorganic flocculant supply amount has already reached the preset upper limit value (for example, “OOml / min”). If the cake moisture content cannot be controlled, an adjustment is made to increase the electroosmotic power by one step (“10 kw” in this embodiment).

  In this case as well, similar to the control method of the seventh and eighth embodiments, an effect (synergistic effect) greater than the sum of the dehydrating effect by adding the inorganic flocculant and the dehydrating effect by electroosmosis is expected. Compared with the case where only one of electroosmosis and inorganic flocculant supply is performed, more efficient dehydration is possible, and a dehydrated cake having a lower moisture content can be obtained.

  Therefore, in parallel with the routine for adjusting the restrictor output (see FIG. 3 (1)), the routine for adjusting the inorganic flocculant supply amount (one of the routines shown in FIGS. 6, 7, and 8) is executed. When the restrictor output is in the maximum state, the cake moisture content exceeds the upper limit for a certain period of time and the inorganic flocculant supply amount has already reached the preset upper limit. Even if the cake water content cannot be brought close to the target value because it has reached, the supply amount cannot be increased any further, and by adjusting the increase in electroosmotic power, Alternatively, the cake moisture content can be effectively reduced by repeating the increase adjustment as many times as necessary, and the cake moisture content can be controlled by adjusting the restrictor output and the inorganic flocculant supply amount. It is possible to return to.

  In addition, in this control method, the routine of “stepwise adjustment of electroosmotic power” shown in FIG. 10 is performed so that the power consumed by electroosmosis can be minimized and the running cost can be reduced. When being executed, the moisture content of the cake is within a certain range centered on the target value (for example, within the range of “target value ± 5%”) or within a certain time (for example, “3 minutes”). ) When the above is continued, adjustment is performed to decrease the electroosmotic power by one step (“10 kW” in the present embodiment).

  Thus, according to this control method, when the rotary pressurization dehydrator 1 is in operation, the cake moisture content approaches the preset target value (converges within a certain range centered on the target value). And the electroosmotic power can be kept to a minimum.

(10th Embodiment)
In the ninth embodiment, the electroosmotic power is adjusted stepwise (increase adjustment or decrease adjustment) depending on the situation, but the electroosmotic power is adjusted by PID control. You can also

  Specifically, in parallel with the routine for adjusting the restrictor output (see FIG. 3 (1)), the routine for adjusting the inorganic flocculant supply amount (any of the routines shown in FIGS. 6, 7, and 8). Is executed, the restrictor output is the maximum, the measured value of the moisture content of the cake is higher than the target value, and exceeds the preset upper limit value (for example, “target value + 10%”). The cake continues for a certain period of time (for example, “3 minutes”) and the supply amount of the inorganic flocculant has already reached the preset upper limit value. When the control means detects that the moisture content cannot be brought close to the target value (satisfaction of the “electroosmosis start condition”), a routine that starts the electroosmosis dehydration and adjusts the restrictor output ( FIG. 3 (1) In parallel with the routine for adjusting the inorganic flocculant supply amount (any one of the routines shown in FIGS. 6, 7, and 8), the routine for “adjustment of electroosmotic power by PID control” (FIG. 4). Any one of the routines shown in FIG. 5 is executed.

  When the routine of “adjustment of electroosmotic power by PID control” shown in FIG. 4 or FIG. 5 is executed, the cake moisture content and the restrictor output are within a certain range centered on the target value. (For example, within the range of “target value ± 5%”) that the state maintained in each state continues for a certain time (for example, “3 minutes”) or longer (satisfaction of the electroosmosis termination condition) is detected by the control means In this case, the routine of “adjustment of electroosmotic power by PID control” is finished once and the restrictor output is adjusted until the “electroosmosis start condition” is satisfied again (FIG. 3 (1 )) And only the routine for adjusting the inorganic flocculant supply amount (any one of the routines shown in FIGS. 6, 7, and 8) is executed.

  Even in such a configuration, as in the control method of the ninth embodiment, the cake moisture content approaches the preset target value when the rotary pressurization dehydrator 1 shown in FIG. 1 is in operation. In addition to being able to control (so as to converge within a certain range centered on the target value), the electroosmotic power can be minimized.

  In the control method of the first to tenth embodiments, as shown in FIG. 1, the rotary pressure dehydrator 1 in which the vertical restrictor 12 is disposed at the cake outlet 8 is the control target. However, instead of the vertical restrictor 12, as shown in FIG. 11, the lateral restrictor 11 (back pressure plate) whose tip side is displaced in the horizontal direction is reduced (the opening area of the cake outlet 8 is reduced, and sludge near the cake outlet 8 is removed. The rotary pressure dehydrator 1 is arranged on one side of the cake outlet 8 with a back pressure device configured to compress and to increase the compressive force acting on the sludge that follows. It can also be controlled.

  Similar to the operation of the vertical restrictor 12, the operation of the lateral restrictor 11 is also an air spring device (a cylinder, a piston inserted into the cylinder, a push rod connected to the piston, and a compressed air supplied into the cylinder). By an electro-pneumatic converter or the like, or by an air bag, a push rod connected to the outside of the airbag and displaced by inflation / deflation of the airbag, and an electro-pneumatic converter for supplying compressed air into the airbag The push rod pressure (restrictor output) is achieved by adjusting the amount of compressed air supplied to the cylinder of the air spring device (electro-pneumatic converter output). ) And the amount of displacement can be adjusted.

  In the rotary pressure dehydrator 1, the information on the measured value of the cake moisture content may be acquired by a moisture meter (microwave type, near infrared type, etc.) disposed outside the cake outlet 8. The value of the outlet pressure (in-machine pressure (kPa) near the cake outlet 8) measured by the pressure sensor arranged inside the cake outlet 8 has a “negative correlation” with the value of the cake moisture content. A cake moisture content value may be estimated from the pressure value, and the estimated value may be regarded as a measured value of the cake moisture content.

  Moreover, in the said embodiment, although the control method in the case of dehydrating "sludge" as a process target object was demonstrated, the process target object in the control method which concerns on this invention is not limited to "sludge", Other things It can also be applied when dehydrating as a processing object.

  1, the nozzle 15 at the tip of the flocculant flow path 14 for supplying the flocculant into the filter chamber 9 is disposed on the inner peripheral surface of the outer spacer 4. 12 and 13, the flocculant flow path 14 is formed inside the electrode portion 10, and the nozzle 15 is disposed on the upstream side of the electrode portion 10 (side facing the proceeding sludge). It can also be configured to be arranged in a direction that can release the flocculant in the direction opposite to the traveling direction. Further, as shown in FIG. It is also possible to arrange it so that the flocculant can be discharged in the same direction as the direction of the sludge.

1: Rotary pressure dehydrator,
2: Rotating shaft,
3: Inner spacer,
4: Outer spacer,
5: Deflector,
6: Screen,
7: Stock solution supply port,
8: Cake exit,
9: Filter chamber
10: electrode part,
11: Lateral restrictor,
12: Vertical restrictor,
13: Push rod,
14: flocculant flow path,
15: Nozzle,
16: Prop,
17: Load cell

Claims (22)

Rotating shaft, inner spacer, outer spacer, deflector, two metal screens fixed to both side surfaces of the inner spacer, and control means, from the stock solution supply port, inner spacer, deflector and outer spacer The object to be treated introduced into the annular filter chamber formed between the two is moved forward by rotating the two screens, and is gradually compressed and filtered and compressed. A restrictor that is displaced in the horizontal direction is a method for controlling a rotary pressurizing dehydrator arranged at the cake outlet,
The rotary pressure dehydrator has electroosmotic dehydration means,
The restrictor output is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value, and the cake moisture content is controlled, and the adjustment of the restrictor output by PID control is executed.
In a state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the electroosmotic power is stepped. A method for controlling a rotary pressurizing dehydrator, wherein adjustment or adjustment of electroosmotic power by PID control is performed in parallel with adjustment of restrictor output by PID control.   In the state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the electroosmotic power is reduced by one step. Adjustment is made to increase, and when the restrictor output value continues for a certain period of time within the range below the preset reference value, adjustment to reduce the electroosmotic power by one step is performed to control the cake moisture content. The method according to claim 1, wherein stepwise adjustment of electroosmotic power is performed.   In the state where the restrictor output is maximum, the electroosmotic dehydration is started when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit for a certain period of time. The electroosmotic power is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value and / or the deviation between the restrictor output value and the target value. The method of controlling a rotary pressurization dehydrator according to claim 1, wherein adjustment of electroosmotic power by PID control in which the output of the restrictor is controlled is executed.   When adjustment of electroosmotic power by PID control is being executed, the cake moisture content and / or restrictor output value is maintained within a certain range centered on the target value for a certain time or more. 4. The method of controlling a rotary pressurization dehydrator according to claim 3, wherein, when the electroosmosis dehydration is continued, the electroosmosis dehydration is stopped and the adjustment of the electroosmosis power by the PID control is once ended. Rotating shaft, inner spacer, outer spacer, deflector, two metal screens fixed to both side surfaces of the inner spacer, and control means, from the stock solution supply port, inner spacer, deflector and outer spacer The object to be treated introduced into the annular filter chamber formed between the two is moved forward by rotating the two screens, and is gradually compressed and filtered and compressed. A restrictor that is displaced in the horizontal direction is a method for controlling a rotary pressurizing dehydrator arranged at the cake outlet,
The rotary pressure dehydrator has a flocculant supply means,
The restrictor output is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value, and the cake moisture content is controlled, and the adjustment of the restrictor output by PID control is executed.
In the state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the inorganic flocculant supply amount A method of controlling a rotary pressurizing dehydrator, wherein stepwise adjustment or adjustment of an inorganic flocculant supply amount by PID control is performed in parallel with adjustment of a restrictor output by PID control.   In the state where the restrictor output is the maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the inorganic flocculant supply amount is reduced. Adjustment is made to increase by one step, and when the restrictor output value continues for a certain period of time within the range below the preset reference value, adjustment is made to reduce the amount of inorganic flocculant supplied by one step and the moisture content of the cake The method for controlling a rotary pressure dehydrator according to claim 5, wherein a stepwise adjustment of the supply amount of the inorganic flocculant is performed, wherein the rate is controlled.   In a state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the supply of the inorganic flocculant is continued for a certain time or more. The inorganic flocculant supply amount is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value and / or the deviation between the restrictor output value and the target value. 6. The method of controlling a rotary pressure dehydrator according to claim 5, wherein adjustment of the supply amount of the inorganic flocculant by PID control in which the cake moisture content and / or restrictor output is controlled is executed.   When adjustment of the inorganic flocculant supply amount by PID control is being executed, the cake moisture content and / or restrictor output value is maintained within a certain range centered on the target value. The method for controlling a rotary pressure dehydrator according to claim 7, wherein the supply of the inorganic flocculant is stopped and the adjustment of the inorganic flocculant supply amount by the PID control is once ended when the operation continues for a time or longer. . Rotating shaft, inner spacer, outer spacer, deflector, two metal screens fixed to both side surfaces of the inner spacer, and control means. The object to be treated introduced into the annular filter chamber formed between the two is moved forward by rotating the two screens, and is gradually compressed and filtered and compressed. A restrictor that is displaced in the horizontal direction is a method for controlling a rotary pressurizing dehydrator arranged at the cake outlet,
The rotary pressure dehydrator has electroosmotic dehydration means and flocculant supply means,
The restrictor output is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value, and the cake moisture content is controlled, and the adjustment of the restrictor output by PID control is executed.
In a state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the electroosmotic power is stepped. Adjustment or adjustment of electroosmotic power by PID control is executed in parallel with adjustment of restrictor output by PID control,
When stepwise adjustment of electroosmotic power or adjustment of electroosmotic power by PID control is performed, electroosmotic power reaches a preset upper limit value, making it impossible to control cake moisture content. In this case, the stepwise adjustment of the inorganic flocculant supply amount or the adjustment of the inorganic flocculant supply amount by the PID control is based on the stepwise adjustment of the electroosmotic power or the adjustment of the electroosmotic power by the PID control and the PID control. A control method of a rotary pressurizing dehydrator, which is executed in parallel with the adjustment of the restrictor output.   When the electroosmotic power reaches a preset upper limit value and the moisture content of the cake cannot be controlled, an adjustment is made to increase the inorganic flocculant supply amount by one step, and the restrictor output value is Incremental supply of inorganic flocculant is controlled in such a way that the moisture content of the cake is controlled by adjusting the amount of inorganic flocculant to be reduced by one step when it continues for a certain time in the range below the set reference value. The method of controlling a rotary pressure dehydrator according to claim 9, wherein the method is executed.   When the electroosmotic power reaches a preset upper limit value and the moisture content of the cake cannot be controlled, the supply of the inorganic flocculant is started, and the supply amount of the inorganic flocculant is the measured value of the cake moisture content. PID control in which the cake moisture content and / or restrictor output is controlled by adjusting to an optimum value calculated based on the deviation between the target value and / or the deviation between the restrictor output value and the target value The method for controlling a rotary pressurizing dehydrator according to claim 9, wherein the adjustment of the supply amount of the inorganic flocculant is performed.   When adjustment of the inorganic flocculant supply amount by PID control is being executed, the cake moisture content and / or restrictor output value is maintained within a certain range centered on the target value. 12. The method for controlling a rotary pressure dehydrator according to claim 11, wherein the supply of the inorganic flocculant is stopped and the adjustment of the inorganic flocculant supply amount by the PID control is once ended when the operation continues for a time or longer. . Rotating shaft, inner spacer, outer spacer, deflector, two metal screens fixed to both side surfaces of the inner spacer, and control means, from the stock solution supply port, inner spacer, deflector and outer spacer The object to be treated introduced into the annular filter chamber formed between the two is moved forward by rotating the two screens, and is gradually compressed and filtered and compressed. A restrictor that is displaced in the horizontal direction is a method for controlling a rotary pressurizing dehydrator arranged at the cake outlet,
The rotary pressure dehydrator has electroosmotic dehydration means and flocculant supply means,
The restrictor output is adjusted to the optimum value calculated based on the deviation between the measured value of the cake moisture content and the target value, and the cake moisture content is controlled, and the adjustment of the restrictor output by PID control is executed.
In the state where the restrictor output is maximum, when the measured value of the cake moisture content is higher than the target value and exceeds the preset upper limit value, the inorganic flocculant supply amount Stepwise adjustment or adjustment of the inorganic flocculant supply amount by PID control is performed in parallel with adjustment of the restrictor output by PID control.
When stepwise adjustment of the inorganic flocculant supply amount or adjustment of the inorganic flocculant supply amount by PID control is being executed, the inorganic flocculant supply amount reaches a preset upper limit value, and the moisture content of the cake When the control of the electrocoagulant becomes impossible, the stepwise adjustment of the electroosmotic power or the adjustment of the electroosmotic power by PID control is the stepwise adjustment of the inorganic coagulant supply amount or the adjustment of the inorganic coagulant supply amount by the PID control. And a control method of the rotary pressurizing dehydrator, which is executed in parallel with the adjustment of the restrictor output by the PID control.   When the inorganic flocculant supply amount reaches a preset upper limit value and the moisture content of the cake cannot be controlled, an adjustment is made to increase the electroosmotic power by one step, and the restrictor output value is Step-by-step adjustment of electroosmotic power is performed, where the cake water content is controlled by adjusting the electroosmotic power to decrease by one step when it continues for a certain time within the range below the set reference value. The control method of the rotary pressurization dehydrator according to claim 13 characterized by these.   When the supply of the inorganic flocculant reaches the preset upper limit value and the control of the moisture content of the cake becomes impossible, the electroosmotic dehydration is started, and the electroosmotic power becomes the measured value of the moisture content of the cake and the target. Electricity by PID control in which the cake moisture content and / or restrictor output is controlled by adjusting to an optimum value calculated based on the deviation from the value and / or the deviation between the restrictor output value and the target value The method of controlling a rotary pressurizing dehydrator according to claim 13, wherein the adjustment of the osmotic power is performed.   When adjustment of electroosmotic power by PID control is being executed, the cake moisture content and / or restrictor output value is maintained within a certain range centered on the target value for a certain time or more. The method of controlling a rotary pressurizing dehydrator according to claim 15, wherein, when continued, the electroosmotic power is stopped and the adjustment of the electroosmotic power by the PID control is once ended.   The electroosmotic dewatering means is composed of a metal electrode portion arranged at the rear stage of the filter chamber and a power supply device electrically connected to the electrode portion and the screen. The electrode portion serves as an anode and the screen serves as a direct current. The rotary pressurization according to any one of claims 1 to 4, and 9 to 16, wherein the electroosmosis dehydration can be performed in the rotary pressurization dehydrator by applying a voltage. Control method of pressure dehydrator.   The flocculant supply means is composed of a flocculant flow path that penetrates from the outer peripheral side to the inner peripheral side of the outer spacer at the rear stage of the filter chamber, and a nozzle disposed at the tip thereof. It is comprised so that it can supply, The control method of the rotary pressurization dehydrator in any one of Claims 5-16 characterized by the above-mentioned.   The flocculant supply means is disposed in a direction capable of releasing the flocculant in a direction opposite to the traveling direction of the object to be treated at a position on the upstream side of the flocculant channel formed inside the electrode portion and the electrode portion. An inorganic flocculant can be supplied into the filter chamber by a nozzle and / or a nozzle arranged at a position downstream of the electrode portion in a direction capable of releasing the flocculant in the same direction as the traveling direction of the processing object. It is comprised as follows, The control method of the rotary pressurization dehydrator in any one of Claims 9-16 characterized by the above-mentioned. The rotary pressure dehydrator has a moisture content meter placed outside the cake outlet,
The method of controlling a rotary pressurization dehydrator according to any one of claims 1 to 19, wherein information on a measured value of the cake moisture content is acquired by a moisture meter. The rotary pressurization dehydrator has a load cell that measures the main body load applied to the outer spacer,
The value of the cake moisture content is estimated from the value of the main body load load measured by the load cell, and the estimated value is regarded as the measured value of the cake moisture content. Control method of pressure dehydrator. The rotary pressure dehydrator has a pressure sensor arranged inside the cake outlet,
The value of the cake moisture content is estimated from the value of the outlet pressure measured by the pressure sensor, and the estimated value is regarded as the measured value of the cake moisture content. Control method of pressure dehydrator.

Images