JP2005052776A - Processing method for and processing apparatus of flying ash - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method for flying ash for adjusting addition amounts of water / a chelate / a pH adjuster in accordance with variation in supply amount of the flying ash, and a processing apparatus therefor. <P>SOLUTION: Moisture content of the flying ash in a kneading machine 3 is measured by using a neutron moisture meter 36 and the addition amount of water is controlled by opening and closing operation of a water amount regulating valve so that the measured result coincides with a set value of water content required in advance. Simultaneously, a supply amount of the flying ash to the kneading machine 3 is calculated on the basis of the moisture content of the flying ash in the kneading machine 3 and a flow rate of water passing through a water pipe 26. Then the addition amounts of the chelate/ the pH adjuster are calculated on the basis of the supply amount of the flying ash, a set value of a chelate addition rate required in advance and a set value of a pH adjuster addition rate. A chelate flow rate regulating valve 28 and a pH adjuster flow rate regulating valve 31 are opened and closed respectively so as to attain the calculated addition amounts. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fly ash treatment method and a treatment apparatus for detoxifying fly ash contained in an exhaust gas generated mainly by incineration and melting of waste and collected in an exhaust gas treatment facility.

  Conventionally, fly ash is contained in exhaust gas generated in incineration facilities and melting facilities, and the fly ash is collected by a dust collector such as a bag filter installed in the exhaust gas treatment facility. Since the fly ash collected in this way contains high concentrations of harmful heavy metals, it cannot be disposed of untreated. Therefore, a fixed amount of fly ash as much as possible is supplied into the kneader, and water and a heavy metal stabilizer set in accordance with the supply amount of the fly ash are added to the fly ash in the kneader and kneaded. By curing and solidifying fly ash, elution of heavy metals from the fly ash is prevented. In addition to the water / heavy metal stabilizer, in addition to the water / heavy metal stabilizer, in addition to the water / heavy metal stabilizer, a pH corresponding to the supply amount of the fly ash is particularly harmful among heavy metals contained in the fly ash. In some cases, an adjusting agent is added to the fly ash in the kneader to adjust the pH value of the fly ash to a value (9 to 11) in which Pb hardly dissolves (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-138129

  However, these technologies for treating fly ash are technologies based on the assumption that a certain amount of fly ash is supplied, and thus cannot cope with fluctuations in the supply amount of fly ash. For this reason, when fly ash bridging phenomenon, fly ash level change, etc. occur in the fly ash storage hopper, the fly ash supply will fluctuate, resulting in a fly amount that is less or greater than expected. Ashes are supplied into the kneader, and accordingly, there is a problem that the moisture content of the fly ash after kneading, the addition rate of the heavy metal stabilizer, and the addition rate of the pH adjuster fluctuate.

  In this way, when an excessive amount of fly ash is supplied to the kneading machine, the moisture content of the fly ash becomes high, and not only the transportation of the fly ash after kneading becomes difficult. In addition, fly ash with insufficient curing may be sent into the storage hopper, pit, etc., and solidify in the hopper / pit, etc., which may hinder driving. Moreover, since an excessive amount of heavy metal stabilizer / pH adjuster is added to the fly ash, there is a problem that the cost is wasted.

  On the other hand, when an excessive amount of fly ash is supplied to the kneader, the water content of the fly ash becomes low, and the fly ash in the ash solidified product pit set downstream of the kneader or at the final disposal site. Has the problem of dusting. Moreover, since the addition amount of the heavy metal stabilizer / pH adjuster becomes insufficient, there is a problem that the effect of the heavy metal stabilizer / pH adjuster cannot be sufficiently obtained.

  The present invention has been made to solve such problems, and it is possible to obtain an optimum amount of added water and an added amount of heavy metal stabilizer according to fluctuations in the supply amount of fly ash. An object of the present invention is to provide a processing method and a processing apparatus.

In order to achieve the above object, the fly ash treatment method according to the present invention comprises:
A fly ash treatment method comprising a kneader for adding and kneading at least water and a heavy metal stabilizer to the fly ash supplied therein, the moisture content of the fly ash after being kneaded in the kneader set in advance The amount of water added to the fly ash is controlled based on the set value of the moisture content, and the water content of the fly ash after kneading and the water added to the fly ash supplied to the kneader The amount of fly ash supplied into the kneader is calculated on the basis of the amount of water and the amount of heavy metal stabilizer added is controlled on the basis of the result of the calculation and a preset value of the heavy metal stabilizer addition rate. (First invention).

Next, the fly ash treatment method according to the second invention is:
A method for treating fly ash comprising a kneader for adding and kneading at least a heavy metal stabilizer and additional water after previously adding and kneading a fixed amount of water to the fly ash supplied therein, wherein the fixed amount of water After the water was added and kneaded, and before adding the heavy metal stabilizer and additional water, the moisture content of the fly ash was measured, and this measurement result and the addition of a predetermined amount of water previously added to the fly ash Based on the amount, the supply amount of fly ash supplied to the kneader is calculated, and based on this calculation result and the preset value of the moisture content and the preset value of the addition rate of the heavy metal stabilizer, additional water and The addition amount of the heavy metal stabilizer is controlled.

The fly ash treatment apparatus according to the third invention is
A kneader for adding and kneading water and a heavy metal stabilizer to the fly ash supplied inside;
Moisture measuring means for measuring the moisture content of fly ash after being kneaded in this kneader;
Water addition amount control means for controlling the amount of water added to the fly ash based on the measurement result by the moisture measuring means and the set value of the moisture content of the fly ash obtained in advance,
Water addition amount detecting means for detecting the amount of water added to the fly ash;
Based on the amount of water added to the fly ash detected by the water addition amount detection means and the water content of the fly ash measured by the moisture measuring means, the supply amount of the fly ash supplied to the kneader is calculated. Fly ash supply amount calculating means for calculating;
Heavy metal stabilizer that controls the amount of heavy metal stabilizer added to the fly ash based on the supply amount of fly ash determined by the fly ash supply amount calculation means and the preset value of the addition rate of the heavy metal stabilizer determined in advance An addition amount control means is provided.

  In the third aspect of the invention, the fly ash in the kneader is added with a pH adjuster in addition to water and a heavy metal stabilizer. Further, the fly ash supply amount obtained by the fly ash supply calculating means is obtained in advance. It is preferable to provide a pH adjuster addition amount control means for controlling the amount of the pH adjuster added to the fly ash based on the set value of the added pH adjuster (fourth invention).

Next, the fly ash treatment apparatus of the fifth invention is:
A kneader for adding a predetermined amount of water in advance to the fly ash supplied inside and kneading, and then adding and kneading a heavy metal stabilizer and additional water,
Moisture measuring means for measuring the moisture content of fly ash after addition of a constant amount of water and kneading, and before addition of heavy metal stabilizer and additional water,
A fly ash supply amount calculating means for calculating a supply amount of fly ash supplied to the kneader based on a measurement result by the moisture measuring means and a predetermined amount of water added to the fly ash in advance;
Based on the fly ash supply amount calculated by the fly ash supply amount calculation means and the set value of the moisture content obtained in advance, the added water amount control means for controlling the additional water addition amount,
Based on the fly ash supply amount calculated by the fly ash supply amount calculating means and the preset value of the heavy metal stabilizer addition rate determined in advance, the amount of heavy metal stabilizer added to the fly ash in the kneader is calculated. A heavy metal stabilizer addition amount control means for controlling is provided.

In the fifth aspect of the invention, the fly ash in the kneader after the water has been added in advance is added with a pH adjuster in addition to the heavy metal stabilizer and additional water, and the moisture detecting means has the constant amount of water. In the fly ash after being added and kneaded, and detecting the moisture of the fly ash before the addition of the heavy metal stabilizer, additional water and pH adjuster,
Further, based on the fly ash supply amount calculated by the fly ash supply amount calculating means and the preset value of the addition rate of the pH adjuster obtained in advance, the addition of the pH adjuster added to the fly ash in the kneader It is preferable to provide a pH adjuster addition amount control means for controlling the amount (the sixth invention).

  In the third to sixth inventions, the moisture measuring means is preferably a neutron moisture meter (seventh invention).

  According to the first invention, the moisture content of the fly ash that varies with the variation in the supply amount of the fly ash is measured, and the fly ash is converted into the fly ash based on the moisture content of the fly ash and the preset moisture content. The amount of water added is adjusted. Therefore, even if the fly ash supply amount fluctuates and the fly ash moisture content fluctuates, the amount of water added is adjusted according to the fluctuation of the moisture content, and the fly ash moisture content is within the allowable range. Can be prevented from departing from. Also, the amount of fly ash supplied is calculated based on the water content of the fly ash and the amount of water added to the fly ash in the kneader, and the amount of heavy metal stabilizer added is controlled based on the amount of fly ash supplied. Therefore, even when the supply amount of fly ash fluctuates, the addition amount of the heavy metal stabilizer can be kept optimal. As a result, it is possible to eliminate flying ash solidified product storage equipment and final disposal form due to the water content being too low, and to eliminate trouble in the ash solidified equipment due to the water content being too high. it can. Moreover, elution of heavy metals can be reliably prevented, and the amount of heavy metal stabilizer added can be minimized. Furthermore, it is not necessary to use an expensive fly ash supply device with high quantitativeness like a table feeder, and the initial cost can be reduced.

  In the second invention, the moisture content of the fly ash in the stage before the addition of the water / heavy metal stabilizer is measured, the supply amount of the fly ash is obtained based on the measurement result, and the supply amount of the fly ash is used. Since the addition amount of the water / heavy metal stabilizer is controlled, the addition amount of the water / heavy metal stabilizer can be reliably controlled in real time according to the fluctuation of fly ash.

  Next, the third invention has been made to embody the first invention, and can obtain the same effects as the first invention.

  Further, by adopting the configuration of the fourth invention, there is an effect that the addition amount of the pH adjusting agent can be appropriately adjusted according to the fluctuation of the supply amount of fly ash.

  Next, the fifth aspect of the invention has been made to embody the second aspect of the invention, and can obtain the same effects as the second aspect of the invention.

  In addition, by adopting the configuration of the sixth aspect of the invention, it is possible to control the addition amount of the pH adjusting agent corresponding to the supply amount of fly ash in real time.

  Furthermore, in the third to sixth inventions, by adopting the configuration of the seventh invention, the moisture content of the fly ash in the kneader can be easily measured in a non-contact manner, and the control accuracy is improved. Can do.

  Next, specific embodiments of the fly ash treatment method and treatment apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram of a fly ash treatment apparatus according to the first embodiment of the present invention.

  The fly ash treatment apparatus 1 according to the present embodiment temporarily stores fly ash generated by waste treatment in the incineration facility and the melting facility, and discharges the fly ash to the outside through the fly ash supply device 2 ′ provided at the bottom. While taking in the fly ash which is distribute | arranged downstream from the tank 2 and this fly ash storage tank 2, and is supplied by the said fly ash supply apparatus 2 ', water, a heavy metal stabilizer (chelate), and a pH adjuster are added to the fly ash Is added, kneaded and discharged from the system. Below the kneading machine 3 is disposed a curing conveyor 4 for conveying the fly ash after kneading discharged from the kneading machine 3 to the ash solidified product pit (not shown) on the downstream side while curing and solidifying. Yes. Moreover, in order to add water, a chelate, and a pH adjuster to the fly ash in the said kneader 3, the water storage tank 5, the chelate storage tank 6, and the pH adjuster storage tank 7 are each arrange | positioned.

  As shown in FIG. 2, the kneader 3 has a hopper 10 for temporarily storing fly ash supplied from the fly ash storage tank 2 at the uppermost upstream end, and after kneading at the lowermost downstream end. A casing 12 having a discharge port 11 for discharging the fly ash on the curing conveyor 4 is provided. A first inlet 13a for injecting a mixed solution of a pH adjuster / water is disposed at an upper upstream portion of the casing 12 and slightly downstream of the hopper 10, and this first inlet 13a is disposed. A second injection port 13b for injecting a mixed solution of chelate and water is disposed at a position downstream of the injection port 13a and slightly downstream of the upper center of the casing 12.

  In the casing 12, a pair of shaft bodies 15, 15 (only the shaft body 15 on the front side is shown) are arranged in parallel, and the shaft bodies 15, 15 are rotated behind the casing 12. An electric motor 16 and a speed reducer 17 are arranged for driving. Further, the shaft body 15 is formed at a position excluding the lowermost end portion with two feed screws 18 for feeding the inner kneaded material (fly ash) toward the downstream side and a plurality of kneading paddles 19. Two kneading parts 20 for kneading fly ash in the kneading machine 3 are arranged in order of the feed screw 18, the kneading part 20, the feed screw 18, and the kneading part 20 from the upstream side to the downstream side. ing. A return screw 22 is disposed at the lowermost end of the shaft bodies 15 and 15.

  The chelate reservoir 6 is connected to a base end of a chelate pipe 24, and the pH adjuster 7 is connected to a base end of a pH adjuster pipe 25. The other end of the chelate pipe 24 is connected to the chelate reservoir 24. Is connected to the second inlet 13b of the kneading machine 3, and the other end of the pH adjusting agent pipe 25 is connected to the first inlet 13a. On the other hand, the water storage tank 5 is connected to a proximal end portion of a water pipe 26 that is bifurcated in the middle, and one other end portion of the water pipe 26 is connected to the chelate pipe 24 and the other other end portion. Are connected to the pH adjusting agent pipe 25, respectively. As a result, the pH adjuster / water mixture is added to the fly ash in the kneader 3 through the first inlet 13a, and the chelate / water mixture is added to the kneader 3 through the second inlet 13b. Added to the fly ash.

  In the middle of the chelate pipe 24 and upstream of the connection with the water pipe 26 (the chelate reservoir 6 side), the flow rate of the chelate passing through the pump 27 and the chelate pipe 24 is adjusted. A chelate flow rate adjusting valve 28 for adjusting the amount of chelate added to the fly ash in the kneader 3 and a chelate flow rate sensor 29 for detecting the flow rate of the chelate passing through the chelate pipe 24 are from the chelate reservoir 6 side. Arranged in order. The flow rate of the pH adjusting agent passing through the pump 30 and the pH adjusting agent pipe 25 is adjusted in the middle of the pH adjusting agent pipe 25 and upstream of the connecting portion with the water pipe 26. A pH adjusting agent flow rate adjusting valve 31 and a pH adjusting agent flow rate sensor 32 for detecting the flow rate of the pH adjusting agent are sequentially arranged from the pH adjusting agent storage tank 7 side. Further, in the middle of the water pipe 26 and upstream of the bifurcation point of the water pipe 26, the pump 33 and a water flow sensor for detecting the amount of water flowing through the water pipe 26 (water addition amount detection). Means) 34 and a water amount adjusting valve 35 for adjusting the water amount are arranged in order from the water storage tank 5 side.

  On the other hand, the kneader 3 is provided with a neutron moisture meter (moisture detecting means) 36 for measuring the moisture content of the fly ash after being kneaded by the kneading section 20 on the downstream side. This neutron moisture meter 36 has a phenomenon that when high-speed neutrons irradiated from radioactive materials collide with hydrogen atoms of the same size as neutrons, they interfere with each other and attenuate to become low-speed thermal neutron rays. A sensor head unit that is a moisture meter known per se and that detects the thermal neutron beam generated from the fly ash by irradiating the fly ash after kneading located at the downstream end of the kneader 3 with neutrons 36a and a calculation unit 36b for calculating the moisture content of fly ash in the kneader 3 based on the detection result of the thermal neutron beam by the sensor head unit 36a.

  Further, the calculation unit 36 b has a fly ash supplied to the kneader 3 based on the moisture content of the fly ash measured by the neutron moisture meter 36 and the amount of water added detected by the water flow sensor 34. Based on the measurement result by the neutron moisture meter 36 and the set value of the moisture content set in advance by the operator, the water amount adjustment is performed. A water flow controller 40 that opens and closes the valve 35 is connected.

  The fly ash supply amount calculator 37 is connected to a chelate addition amount calculator 38 and a pH adjuster addition amount calculator 39 so that the fly ash supply amount is transmitted to both the calculators 38 and 39. Has been. Then, in the chelate addition amount calculator 38, the fly ash supply amount based on the fly ash supply amount transmitted from the fly ash supply amount calculator 37 and the set value of the chelate addition rate preset by the operator. In the pH adjuster addition amount calculator 39, based on the supply amount of fly ash and the set value of the pH adjuster addition rate preset by the operator, The addition amount of the pH adjusting agent according to the supply amount of fly ash is calculated. Here, the set value of the moisture content, the set value of the addition rate of the chelate and the set value of the addition rate of the pH adjuster are values obtained based on actual measurement, and the fly ash when the fly ash is well cured and solidified Is used as the setting value of the moisture content, and the addition rate of the chelate / ph adjuster necessary to prevent elution of Pb from the fly ash is the set value of the chelate addition rate, the addition rate of the pH adjuster Each is adopted as a set value.

  The addition amount of the chelate calculated by the chelate addition amount calculator 38 is transmitted to the chelate flow rate controller 41, and the addition amount of the pH adjuster calculated by the pH adjuster addition amount calculator 39 is the pH adjuster. It is transmitted to the flow rate controller 42. Then, in the chelate flow rate controller 41, the chelate flow rate adjustment valve 28 is set so that the addition amount of the chelate to the fly ash detected by the chelate flow rate sensor 29 matches the calculation result by the chelate addition amount calculator 38. When the pH adjusting agent flow rate controller 42 is opened and closed, the amount of the pH adjusting agent added to the fly ash detected by the pH adjusting agent flow rate sensor 32 coincides with the calculation result by the pH adjusting agent addition amount calculator 39. Thus, the pH adjusting agent flow rate adjusting valve 31 is opened and closed.

  In the fly ash treatment apparatus 1 configured as described above, the fly ash in the fly ash storage tank 2 is supplied into the kneader 3 by the fly ash supply apparatus 2 ′ and then passed through the inlets 13a and 13b. These are kneaded by the rotation of the kneading unit 20 together with the mixed solution of pH adjuster / water and the mixed solution of water / pH adjuster, respectively, and sent to the downstream side by the feed screw 18. Then, it discharges | emits on the curing conveyor 4 through the said discharge port 11, is conveyed on the downstream side, solidified on the said curing conveyor 4, and is finally disposed.

  In the present embodiment, the amount of water, chelate, and pH adjuster added to the fly ash in the kneader 3 is controlled as follows according to the fluctuation of the fly ash supply amount.

  First, using the neutron moisture meter 36, the moisture content of fly ash located at the downstream end in the kneading machine 3 and kneaded by each kneading unit 20 is measured, It transmits to the fly ash addition amount calculator 37 and the water flow rate controller 40. In the water flow rate controller 40, the water flow rate adjustment valve 35 is opened and closed so that the moisture content of the fly ash coincides with the moisture content of the fly ash preset by the operator. Thus, the amount of water added to the fly ash in the kneader 3 through the inlets 13a, 13b is controlled.

  On the other hand, in the fly ash addition amount calculator 37, the fly ash supplied from the fly ash supply device 2 ′ to the kneader 3 based on the measurement result by the neutron moisture meter 36 and the detection result by the water flow sensor 34. The supply amount of ash is calculated, and the calculation result is transmitted to the chelate addition amount calculator 38 and the pH adjuster addition amount calculator 39, respectively.

  Next, in the chelate addition amount calculator 38, the chelate addition amount corresponding to the fly ash supply amount is calculated based on the supply amount of the fly ash and the set value of the chelate addition rate preset by the operator. To the chelate flow rate controller 41. In the chelate flow controller 41, the chelate flow rate adjustment valve 28 is opened and closed so that the detection result by the chelate flow rate sensor 29 matches the calculation result by the chelate addition amount controller 41. The amount of chelate added to the fly ash is controlled.

  Similarly, in the pH adjuster addition amount calculator 39, the supply amount of fly ash based on the supply amount of fly ash supplied to the kneader 3 and the set value of the chelate addition rate preset by the operator. The addition amount of the pH adjusting agent corresponding to is calculated and transmitted to the pH adjusting agent flow rate controller 42. In the pH adjuster flow rate controller 42, the pH adjuster flow rate adjustment valve 31 is opened and closed so that the detection result by the pH adjuster flow rate sensor 32 matches the calculation result by the pH adjuster flow rate controller 42. The amount of pH adjuster added to the fly ash in the kneader 3 is controlled.

  In the present embodiment, as described above, the amount of water added is controlled so that the moisture content of the fly ash in the kneader 3 matches the preset value of the moisture content. Even if the fly ash bridge level rises in the ash storage tank 2 and the hopper 10 and the supply amount of the fly ash to the kneading machine 3 fluctuates, the amount of water added is adjusted according to the fluctuation. The moisture content of the kneaded product (fly ash) discharged from the kneader 3 can be kept at a suitable value (specifically, the set value of the moisture content). Therefore, the water content of fly ash can be prevented from deviating from the allowable range, and the fly ash can be suitably cured. As a result, it is possible to prevent fly ash having insufficient curing from solidifying in the storage hopper, the pit, or the like, or to prevent fly ash having a moisture content too low from becoming dust. In the present embodiment, the supply amount of the fly ash is calculated from the moisture content of the fly ash, and the addition amount of the chelate / pH adjusting agent is controlled according to the supply amount of the fly ash. Even when the supply amount of fly ash varies, a necessary and sufficient amount of chelate / pH adjuster can be added. Therefore, the elution of Pb from the fly ash can be reliably prevented, and at the same time, the consumption of the chelate / pH adjuster can be minimized. Further, in this embodiment, since the amount of water, chelate, and pH adjuster added is adjusted according to the variation in the amount of fly ash supplied, supply of expensive fly ash such as a table feeder is provided. Since it is not necessary to make the supply amount of fly ash constant by using the means, the cost can be further saved.

  Furthermore, in this embodiment, since a neutron moisture meter using a (thermal) neutron beam having excellent permeability as a medium is used, the moisture content of fly ash in the kneader 3 is measured in a non-contact manner. Therefore, the accuracy of the entire control can be improved.

  Next, a fly ash treatment apparatus according to a second embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to portions common to the previous embodiment, and detailed description thereof is omitted.

  FIG. 3 shows a system configuration diagram of a fly ash treatment apparatus according to the present embodiment (second embodiment).

  In this embodiment, as shown in FIG. 3, the fly ash treatment apparatus 1A includes three feed screws 18 and three kneading sections 20 from the upstream end to the downstream side in the casing 12 ′. 18, kneading sections 20 are alternately arranged in this order, and a kneading machine 3 ′ is provided in which a return screw 22 is arranged at the downstream end of the casing 12 ′.

  At a position slightly downstream of the hopper 10 of the casing 12 ′ and at a position corresponding to the boundary between the uppermost stream-side feed screw 18 and the uppermost stream kneading section 20, a constant amount of water is introduced into the kneader 3 ′. A water inlet 13 ′ for injecting into the fly ash is arranged, and the first inlet 13a is downstream of the first inlet 13a on the downstream side of the water inlet 13 ′. Are provided with the second inlets 13b, respectively. The neutron is located between the water inlet 13 ′ and the first inlet 13a and at a position corresponding to the boundary between the uppermost kneading part 20 and the second feed screw 18 from the upstream side. A sensor head portion 36a of the moisture meter 36 is attached. As a result, water is added from the water inlet 13 ′ and is fly ash after being kneaded by the most upstream kneading unit 20, and before the addition of the mixed solution of water / pH adjuster and the mixed solution of water / chelate. It is designed to detect the moisture content of fly ash.

  In the present embodiment, the chelate reservoir 6 and the pH adjuster reservoir 7 are connected to the first inlet 13a and the second inlet 13b via the chelate pipe 25 and the pH adjuster pipe 26, respectively. The water storage tank 5 is connected to a base end portion of a water pipe 26 ′ that is branched into a first branch water pipe 26 a ′ and a second branch water pipe 26 b ′. The water pipe 26 'is provided with a first water flow sensor 34a for detecting the flow rate of water passing through the water pipe 26', that is, the total amount of water added to the fly ash in the kneading machine 3 '. ing.

  The first branch water pipe 26a ′ is connected to the water inlet 13 ′. The first branch water pipe 26a ′ is added to the flow rate of water passing through the first branch water pipe 26a ′, that is, to the fly ash in the upstream portion in the kneader 3 through the water inlet 13 ′. A second water flow sensor 34b for detecting the flow rate of water is arranged, and downstream of the second water flow sensor 34b, the flow rate of water passing through the first branch water pipe 26a, that is, the water inlet port. A first water flow rate adjusting valve 35a is provided to keep the flow rate of water added to the fly ash located at the upstream portion in the kneading machine 3 from 13 'substantially constant.

  On the other hand, the second branch water pipe 26b ′ is branched into a third branch water pipe 26c ′ and a fourth branch water pipe 26d ′ on the way, and the tip of the third branch water pipe 26c ′ is used for the chelate. The distal end portion of the fourth branch water pipe 26d ′ is connected to the pipe 24 and the pH adjusting pipe 25, respectively. The second branch water pipe 26b ′ is added to the flow rate of water passing through the second branch water pipe 26b ′, that is, the fly ash in the kneader 3 through the inlets 13a and 13b. A second water flow rate adjusting valve 35b for adjusting the amount of water added is provided.

  In the present embodiment, the second water flow rate sensor 34b uses the detection result (the flow rate of water passing through the first branch water pipe 26a ′) as the fly ash supply amount calculator 37 and the first water flow rate controller. In this first water flow rate controller 51, the flow rate of water flowing through the first branch water pipe 26a ′ matches the set value of the water flow rate preset by the operator. The first water flow rate adjustment valve 35a is opened and closed. Thus, a certain amount of water is added to the fly ash in the kneader 3 from the water inlet 13 '.

  On the other hand, in addition to the detection result by the second water flow rate sensor 34b, the fly ash supply amount calculator 37 transmits the moisture content of the fly ash measured by the neutron moisture meter 36. The kneader based on the detection result (the flow rate of water added to the fly ash upstream of the kneader 3 through the first branch water pipe 26a ′ and the water inlet 13 ′) and the water content of the fly ash. The supply amount of fly ash supplied to 3 'is calculated.

  The fly ash supply amount calculated by the fly ash supply amount calculator 37 is added to the chelate addition amount calculator 38, the pH adjuster addition amount calculator 39, and the fly ash in the kneader 3. Is transmitted to a water addition amount calculator 50 that calculates the total amount of water to be added. In the same manner as in the previous embodiment, the chelate addition amount calculator 38 and the pH adjuster addition amount calculator 39 calculate the addition amount of the chelate / pH adjuster according to the supply amount of fly ash to calculate the chelate. The flow rate controller 41 and the pH adjuster flow rate controller 42 are respectively transmitted, and the chelate flow rate controller 41 and the pH adjuster flow rate controller 42 respectively control the addition amounts of the chelate and the pH adjuster. .

  On the other hand, in the water addition amount calculator 50, each inlet 13 is based on the fly ash supply amount transmitted from the fly ash supply amount calculator 37 and the moisture content set value transmitted in advance by the operator. ', 13a, 13b is used to calculate the total amount of water added to the fly ash in the kneading machine 3, and the calculation result is transmitted to the second water flow rate controller 52. Then, in the second water flow rate controller 52, the detection result by the first water flow rate detection sensor 34a, that is, the water pipe 26 'passes through the inlets 13', 13a, 13b and enters the kneader 3. The second water flow rate adjustment valve 35b is opened and closed so that the total flow rate of the added water matches the calculation result of the water addition amount calculator 50. Thus, the total amount of water added to the fly ash in the kneader 3 ′ is controlled.

  In this embodiment, the upper limit of the moisture content of the fly ash kneaded product is set, and when the moisture content of the fly ash in the kneader 3 exceeds a predetermined upper limit, the fly ash storage tank 2 Some irregularities such as the internal bridging phenomenon occur, and it is determined that the supply of fly ash is not normally performed, and an alarm is issued.

  Next, control of the addition amount of water / chelate / pH adjuster according to the second embodiment will be described.

  In the present embodiment, in the first water flow controller 51, the water detected by the second water flow sensor 34b (the flow of water passing through the first branch water pipe 26a ′) is set by the operator. The first water flow rate adjustment valve 35a is opened and closed so as to coincide with the set value of the flow rate. As a result, a certain amount of water is continuously added to the fly ash in the upstream portion in the kneader 3 through the water inlet 13 '.

  Using the neutron moisture meter 36, fly ash after a fixed amount of water is added from the inlet 13 ', and a mixture of chelate and water from the first and second inlets 13a and 13b And the water content of the fly ash before the addition of the pH adjuster / water mixture is measured and transmitted to the fly ash supply amount calculator 37. Next, in this fly ash supply amount calculator 37, fly ash supplied from the fly ash supply device 2 'to the kneader 3 based on the moisture content of the fly ash and the detection result by the second water flow sensor 34b. The calculation result is transmitted to the chelate addition amount calculator 38, the pH adjuster addition amount calculator 39, and the water flow rate calculator 50, respectively. Then, in the chelate addition amount calculator 38 and the pH adjuster addition amount calculator 39, the chelate flow rate controller 41 and the pH adjuster are calculated by respectively calculating the addition amount of the chelate and the pH adjuster according to the supply amount of fly ash. The data is transmitted to the flow rate controller 42, and the controller 41, 42 opens and closes the chelate flow rate adjustment valve 28 and the pH adjuster flow rate adjustment valve 31. In this way, the addition amount of the chelate / pH adjuster added to the fly ash of the kneading machine 3 ′ is controlled (similar to the previous embodiment).

  On the other hand, in the added water amount calculator 50, based on the added amount of fly ash transmitted from the fly ash supply amount calculator 37 and the set value of the moisture content preset by the operator, The total amount of water supplied to the fly ash (the total amount of water added through the inlets 13 ′, 13 a, 13 b) is calculated and transmitted to the second water flow rate controller 52. Then, in the second water flow rate calculator 52, the second detected value by the first water flow rate sensor 34a matches the total amount of water detected by the first water flow rate sensor 34a. The water flow rate adjustment valve 35b is opened and closed. Thus, the total amount of water added to the fly ash in the kneading machine 3 through the inlets 13 ', 13a, 13b is controlled to be equal to the total amount of water added.

  In this embodiment, based on the fly ash moisture content measured by the neutron moisture meter 36, the supply amount of fly ash supplied from the fly ash supply device 2 ′ into the kneader 3 is calculated. Based on the supply amount of ash, the addition amount of water, chelate, and pH adjuster is controlled so as to correspond to the supply amount of fly ash. Therefore, even when the supply amount of the fly ash varies, the water content of the fly ash, the addition rate of the chelate, and the addition rate of the pH adjuster can be kept within an allowable range.

  In addition, in the present embodiment, the water content of the fly ash in the previous stage where the pH adjuster / water mixture and the chelate / water mixture are added is measured. Since the addition amount of the pH adjusting agent is adjusted, the addition amount of water, chelate, and pH adjusting agent can be controlled in real time and reliably.

  In each of the above embodiments, water / chelate / pH adjuster is added to the fly ash in the kneading machine 3, but only water / chelate may be added to the fly ash. Moreover, in each said embodiment, although chelate was used as a heavy metal stabilizer, heavy metal stabilizers other than a chelate can also be used.

  In the first embodiment, the water pipe 26, the water amount adjusting valve 35, and the water flow rate controller 40 correspond to the water addition amount control means of the present invention. In the second embodiment, the second, third, and third The four branched water pipes 26b ', 26c', 26d ', the second water amount control valve 35b, the water addition amount calculator 50, and the second water flow rate controller 52 correspond to the water addition amount control means of the present invention. In addition, the chelate water pipe 24, the chelate flow rate adjustment valve 28, the chelate addition amount calculator 38, and the chelate addition amount controller 41 in each of the embodiments correspond to the heavy metal stabilizer addition amount control means of the present invention, and are for pH adjusters. The pipe 25, the pH adjusting agent flow rate adjusting valve 31, the pH adjusting agent addition amount calculator 39, and the pH adjusting agent addition amount controller 42 correspond to pH adjusting agent addition amount control means.

System configuration diagram of a fly ash treatment apparatus according to the first embodiment Cross section of kneader System configuration diagram of a fly ash treatment apparatus according to the second embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Fly ash processing apparatus 3, 3 'Kneading machine 5 Water storage tank 6 Chelate storage tank 7 pH adjuster storage tank 24 Chelate pipe 25 pH adjuster pipe 26, 26' Water pipe 26a 'First branch water pipe 26b 'Second branch water pipe 26c' third branch water pipe 26d 'fourth branch water pipe 28 chelate flow rate adjustment valve 29 chelate flow rate sensor 31 pH adjuster flow rate adjustment valve 32 pH adjuster flow rate sensor 34 water flow rate sensor 34a first Water flow sensor 34b Second water flow sensor 35 Water flow adjustment valve 35a First water flow adjustment valve 35b Second water flow adjustment valve 36 Neutron moisture meter 37 Fly ash supply amount calculator 38 Chelate addition amount calculator 39 pH Adjustment agent addition amount calculator 40 Water flow rate controller 41 Chelate addition amount controller 42 pH adjuster addition amount controller 50 Addition water amount calculator 51 First water flow controller 52 Second water flow controller

Claims (7)

  A method for treating fly ash comprising a kneader for adding and kneading at least water and a heavy metal stabilizer to fly ash supplied therein, wherein the moisture content of fly ash after being kneaded in the kneader is preset. The amount of water added to the fly ash is controlled based on the set value of the moisture content, and the water content of the fly ash after kneading and the water added to the fly ash supplied to the kneader The amount of fly ash supplied into the kneader is calculated on the basis of the amount of water and the amount of heavy metal stabilizer added is controlled on the basis of the result of the calculation and a preset value of the heavy metal stabilizer addition rate. A method for treating fly ash, characterized by   A method for treating fly ash comprising a kneader for adding and kneading at least a heavy metal stabilizer and additional water after previously adding and kneading a fixed amount of water to the fly ash supplied therein, wherein the fixed amount of water After the water was added and kneaded, and before adding the heavy metal stabilizer and additional water, the moisture content of the fly ash was measured, and this measurement result and the addition of a predetermined amount of water previously added to the fly ash Based on the amount, the supply amount of fly ash supplied to the kneader is calculated, and based on this calculation result and the preset value of the moisture content and the preset value of the addition rate of the heavy metal stabilizer, additional water and A method for treating fly ash, comprising controlling the amount of heavy metal stabilizer added. A kneader for adding and kneading water and heavy metal stabilizer to the fly ash supplied inside;
Moisture measuring means for measuring the moisture content of fly ash after being kneaded in this kneader;
Water addition amount control means for controlling the amount of water added to the fly ash based on the measurement result by the moisture measuring means and the set value of the moisture content of the fly ash obtained in advance,
Water addition amount detecting means for detecting the amount of water added to the fly ash;
Based on the amount of water added to the fly ash detected by the water addition amount detection means and the water content of the fly ash measured by the moisture measuring means, the supply amount of the fly ash supplied to the kneader is calculated. Fly ash supply amount calculating means for calculating;
Heavy metal stabilizer that controls the amount of heavy metal stabilizer added to the fly ash based on the supply amount of fly ash determined by the fly ash supply amount calculation means and the preset value of the addition rate of the heavy metal stabilizer determined in advance A fly ash treatment apparatus comprising an addition amount control means.   To the fly ash in the kneader, a pH adjuster is added in addition to water and a heavy metal stabilizer. Further, the fly ash supply amount obtained by the fly ash supply calculating means and the addition of the pH adjuster obtained in advance are added. The fly ash treatment apparatus according to claim 3, further comprising a pH adjuster addition amount control means for controlling an addition amount of the pH adjuster to the fly ash based on a set value of the rate. A kneader for adding a predetermined amount of water in advance to the fly ash supplied inside and kneading, and then adding and kneading a heavy metal stabilizer and additional water,
Moisture measuring means for measuring the moisture content of fly ash after addition of a constant amount of water and kneading, and before addition of heavy metal stabilizer and additional water,
A fly ash supply amount calculating means for calculating a supply amount of fly ash supplied to the kneader based on a measurement result by the moisture measuring means and a predetermined amount of water added to the fly ash in advance;
Based on the fly ash supply amount calculated by the fly ash supply amount calculation means and the set value of the moisture content obtained in advance, the added water amount control means for controlling the additional water addition amount,
Based on the fly ash supply amount calculated by the fly ash supply amount calculating means and the preset value of the heavy metal stabilizer addition rate determined in advance, the amount of heavy metal stabilizer added to the fly ash in the kneader is calculated. A fly ash treatment apparatus comprising a heavy metal stabilizer addition amount control means for controlling. In addition to the heavy metal stabilizer and additional water, a pH adjuster was added to the fly ash after water was added in advance in the kneader, and the moisture detecting means was added and kneaded with the constant amount of water. Detect the water content of the fly ash after the fly ash and before the addition of the heavy metal stabilizer, the additional water and the pH adjuster,
Further, based on the fly ash supply amount calculated by the fly ash supply amount calculating means and the preset value of the addition rate of the pH adjuster obtained in advance, the addition of the pH adjuster added to the fly ash in the kneader The fly ash treatment apparatus according to claim 5, further comprising a pH adjuster addition amount control means for controlling the amount.   The fly ash treatment apparatus according to claim 3, wherein the moisture measuring means is a neutron moisture meter.

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