JP6331134B2 - Electric dust collection system - Google Patents

Description

  In the present invention, when a defect occurs in a part of the charging circuit of the electrostatic precipitator, the output of the generator is suppressed so that the amount of dust generated in the boiler is reduced so that the amount of dust at the smoke outlet does not exceed the regulation value. In particular, the present invention relates to an electric dust collection system capable of suppressing the amount of dust at a smoke outlet to a regulation value or less by appropriately controlling the amount of dust generated according to the occurrence pattern of charge failure. .

  In a thermal power plant or the like, an electrostatic precipitator is installed to prevent dust contained in combustion exhaust gas from the boiler from being scattered into the atmosphere. An electrostatic precipitator is a structure that rectifies the AC power source into a high-voltage DC power source and flows it to the discharge electrode, so that negative ions are attached to the dust and collected by the dust collecting electrode. Even when a defect occurs, the operation can be continued by disconnecting the corresponding part from the charging circuit. However, depending on the location where the defect occurs, the dust collection efficiency may be significantly reduced, so it is necessary to take appropriate measures according to the location where the defect occurs.

As a solution to such a problem, for example, Patent Document 1 relates to an invention that changes the operation state of an electrostatic precipitator in response to a disturbance under the name “Operation method of an electrostatic precipitator for main exhaust gas of a sintering machine”. The invention is disclosed.
The invention disclosed in Patent Document 1 is based on the input conditions (sintering machine exhaust gas properties, charging conditions of the electrostatic precipitator) and output conditions (dust concentration in the exhaust gas from the precipitator) of the electrostatic precipitator, operating conditions of the sintering machine, and operation of the electrostatic precipitator. Based on conditions, it is the structure which controls a sintering machine and an electrostatic precipitator.
According to such a configuration, it is possible to reduce the soot concentration in the exhaust gas of the electrostatic precipitator in response to fluctuations in the entry conditions of the electrostatic precipitator.

Further, in Patent Document 2, soot dust is sent out from the electrostatic precipitator in order to reduce the soot sent out from the electrostatic precipitator when the dust collecting performance of the electrostatic precipitator is deteriorated under the name “control device of the electrostatic precipitator”. An invention relating to a control device for adjusting the air volume is disclosed.
The invention disclosed in Patent Document 2 is characterized by comprising output / air volume reducing means for reducing the voltage generated by the high voltage generator and the air volume of the fan in response to the detection of arc discharge by the arc discharge detector.
In the “electric dust collector control device” having such a structure, it is possible to obtain predetermined dust collection efficiency in a state where safety is ensured by suppressing the occurrence of arc discharge. In addition, it is possible to prevent contamination inside the electrostatic precipitator that has conventionally occurred in a non-dust collecting state.

JP-A-6-134341 Japanese Patent Laid-Open No. 5-138071

  The electrostatic precipitator may have a significant decrease in dust collection efficiency depending on where charging failure occurs. However, in the inventions described in Patent Document 1 and Patent Document 2 which are the above-described conventional technologies, the configuration is such that the occurrence of charging failure is detected and the generation amount of dust is controlled according to the generation pattern. Absent. Therefore, the amount of dust at the smoke outlet may exceed the regulation value.

  The present invention has been made in response to such a conventional situation, and it is possible to appropriately suppress the amount of dust generated according to the occurrence pattern of the charge failure, and to suppress the amount of dust at the smoke outlet to a regulation value or less. It aims at providing a simple electric dust collection system.

In order to achieve the above object, an invention according to claim 1 is an electric dust collection system for collecting soot and dust contained in combustion exhaust gas generated in a boiler, wherein a plurality of compartments are formed, and each compartment is released. An electrostatic precipitator in which a charging circuit composed of an electrode and a disconnector is installed, a charging failure detection means that is installed in the electrostatic precipitator and detects the ON / OFF state of the disconnector for each section, and an electrostatic precipitator Storage means for storing information on the operating conditions of the collector, calculation means for calculating the amount of dust discharged from the electrostatic precipitator based on the information stored in the storage means and the ON-OFF state pattern of the disconnector, and Load control means for suppressing the generation of dust in the boiler based on the amount of dust at the outlet, and N sections are formed so as to be paired at locations upstream and downstream of the dust flow. The , Of the 2N number of compartments, n with the charged defect occurs in _a number, if successively upstream and downstream in the compartment of n _b-charge defect occurs, the inlet dust amount of the electrostatic precipitator was a W _in, as eta ₀ a dust collecting efficiency of the discharge electrode during normal operation, the calculating means includes calculating means calculates the outlet dust amount W _out2 of electrostatic precipitator based on the equation (11) below To do.

As already described, in the case of an electrostatic precipitator, dust collection efficiency is reduced when a soot deposits on the discharge electrode or the like and a charging failure occurs. However, the degree to which the dust collection efficiency decreases varies depending on the pattern of defective charging. Therefore, if the boiler output is uniformly reduced to reduce the amount of dust generated in power generation facilities, the power generation efficiency is suppressed more than necessary. May not be efficient. On the other hand, if the degree to which the boiler output is reduced is not sufficient, the amount of dust generated may exceed the reference value.
On the other hand, in the electric dust collection system having the above structure, the location where the charge failure occurs is specified based on the detection result of the charge failure detection means, and the dust discharge from the outlet of the electric dust collector is performed by the calculation means based on the occurrence pattern. A quantity is calculated. That is, in the electric dust collection system of the present invention, since the calculation means is configured to calculate the dust collection efficiency of the electric dust collector in consideration of the influence of the charging failure, when the charging electrode has a charging failure However, it works to accurately determine the amount of dust at the outlet of the electrostatic precipitator.

Further, the arithmetic means, and the position of the compartment charged defect occurs, acts to accurately determine the dust collecting efficiency based on the information on whether the partition is continuous with the upstream side and the downstream side.

  When the invention according to claim 1 is applied to a boiler such as a power generation facility, the generation of soot in the boiler is appropriately suppressed without lowering the power generation efficiency more than necessary, and the amount of soot at the smoke outlet is always below the regulation value. Can be suppressed.

Further, it is possible to accurately predict the outlet dust amount of electrostatic precipitator based on the generation pattern of the load electric failure. Therefore, when used for power generation equipment, the upper limit value of the output of the generator can be set to an appropriate value to effectively suppress the generation of dust in the boiler.

(A) And (b) is the block diagram and schematic diagram which respectively show the structure of Example 1 of the electrostatic dust collection system and electrostatic dust collector which concern on embodiment of this invention, (c) is the figure (b) It is the figure which expanded a part of charging circuit shown in FIG. It is the schematic diagram which expanded a part of electrostatic precipitator shown in FIG.1 (b). It is the schematic diagram which expanded a part of electrostatic precipitator shown in FIG.1 (b). (A) And (b) is a block diagram for demonstrating the function of the electric dust collection system of Example 1, and the flowchart which shows the operation | movement procedure, respectively. It is a flowchart which shows the algorithm of the calculation performed in the calculating means of the electric dust collection system of Example 1. It is the schematic diagram which expanded a part of electrostatic precipitator shown in FIG.1 (b). (A) And (b) is a flowchart which shows the block diagram for demonstrating the function of Example 2 of the electrostatic dust collection system which concerns on embodiment of this invention, and its operation | movement procedure, respectively. It is a flowchart which shows the algorithm of the calculation performed in the calculating means of the electric dust collection system of Example 2.

  The configuration of the electric dust collection system of the present invention, and the action and effect based thereon will be specifically described with reference to FIGS. In addition, in Example 1 and Example 2, the case where flue gas is equally distributed with respect to each division in the electrostatic precipitator mentioned later and the case where it is not equally distributed are assumed, respectively.

The structure and operation of the electric dust collection system 1a of the present embodiment will be described with reference to FIGS.
As shown in FIGS. 1 (a) and 1 (b), an electrostatic precipitator system 1a includes an electrostatic precipitator 2 having a detecting means 2a for detecting the occurrence of a charging failure, and an upper limit of the output of the generator 10. It is comprised by the dust generation | occurrence | production suppression apparatus 3 which suppresses generation | occurrence | production of the dust in the boiler 11 by setting a value.
The dust generation suppression device 3 includes an input unit 5 for inputting information related to the operating conditions and the like of the electrostatic precipitator 2, and a calculation unit 6 for calculating a load suppression value (an appropriate upper limit value of the output of the generator 10). The control means 4 for sending the information received from the detection means 2a and the input means 5 to the calculation means 6, the load control means 7 for setting the load suppression value as the upper limit value of the output of the generator 10, and the calculation of the load suppression value A storage unit 8 that stores necessary information and the like, and an output unit 9 that converts a calculation result obtained by the calculation unit 6 into a state that can be visually confirmed, such as being displayed on a screen or printed, are provided. The operation of the input means 5, the calculation means 6, the load control means 7, the storage means 8 and the output means 9 is controlled by the control means 4.

  As shown in FIGS. 1B and 1C, steam used for a steam turbine connected to the generator 10 is supplied from a boiler 11. Smoke generated in the process of generating steam in the boiler 11 is sent to the electrostatic precipitator 2 after harmful gases are removed by a denitration device (not shown). And inside the electric dust collector 2, this flue gas branches into two systems (hereinafter referred to as A system and B system, respectively). After negative ions are attached to the soot by the discharge electrode 12, the soot is It is collected by a dust collecting electrode (not shown) and finally discharged from the chimney 13 into the atmosphere.

In the A system and the B system, four sections are formed so as to be paired at locations on the upstream side and the downstream side with respect to the dust flow, and the discharge electrode 12 and the disconnector 14 are formed in each section. A charging circuit comprising: When the disconnector 14 is in an ON state, a high-voltage direct current is supplied from the rectifier 15 to the discharge electrode 12 via the disconnector 14. However, if the discharge electrode 12 is short-circuited due to dust or the like, the disconnector 14 14 is switched to the OFF state, and the supply of power from the rectifier 15 to the discharge electrode 12 is cut off.
When detecting the position of the disconnector 14 in the OFF state, the detection means 2a generates an OFF signal indicating that a charging failure has occurred. This OFF signal is sent to the control means 4 together with the detected position information of the disconnector 14.

  As shown to Fig.2 (a), the code | symbol of A1-A4 and B1-B4 is attached | subjected to the division formed in the inside of the electrostatic precipitator 2, respectively. In addition, dampers (not shown) whose opening degree is adjusted manually or automatically at the upstream inlet and the downstream outlet are respectively installed so as to correspond to each section, and 20 rows of dust collecting electrodes per section Nine (not shown) are installed on the upstream side and the downstream side, respectively. In addition, when a charging failure occurs continuously on the upstream side and the downstream side, the damper at that point is fully closed until the charging failure is eliminated.

In general, the dust collection efficiency η of the electrostatic precipitator 2 is expressed by the following formula (1) (Deutsche formula) where ω is the dust moving speed and f is the dust collection area per unit gas. In the case of the present embodiment, since the dust collecting electrodes are installed in half on the upstream side and the downstream side, the dust collection area per unit gas is f / 2. Therefore, if the dust collection efficiency (planned efficiency) η in the formula (1) is 91%, when all the dampers are fully opened, the upstream dust collection efficiency η ₁ and the downstream dust collection efficiency η ₂ are As shown in the following formula (2), both are 70%.

Furthermore, one of the N sections of the upstream side or downstream side _{n a} compartment of the (8 compartments A1~A4 and B1~B4 in this embodiment) (where, _{n a} ≦ 8) charged defect occurred in Then, the upstream and downstream dust collection efficiencies η ₁ and η ₂ are expressed by the following equation (3).

Here, when the inlet dust amount of the electrostatic precipitator 2, W _in, the outlet dust amount W _out of the electrostatic precipitator 2 is expressed by the following equation (4). At this time, since the entire dust collection efficiency η ₁₂ is expressed by Expression (5), the relationship of Expression (6) is established between η ₁ and η ₂ and η ₁₂ . However, in the equation (6), the dust collection efficiency in which no charging failure has occurred among the upstream dust collection efficiency η ₁ and the downstream dust collection efficiency η ₂ is η ₀ shown in the equation (2). (= 0.7). Also, if n _c portion of the damper is fully closed at the downstream outlet, the dust collection efficiency eta ₂ of the downstream side rather than the formula (3), the formula (7). In Equation (7), the flue gas flowing from the upstream side, the damper is assumed to be evenly distributed into the other compartment with the exception of n _c partition which is fully closed.

Further, when the target value of the dust amount in the chimney outlet and W _P, the outlet dust amount of the electrostatic precipitator 2 W _out must be less than W _P as shown in equation (8). Therefore, if the inlet dust amount W _in the electrostatic precipitator 2 is proportional to the output of the generator 6, the load suppression value P is the use of the upper limit value P ₀ of the output of the generator 10, as shown in equation (9) Represented.

The calculation method of the load suppression value P will be specifically described with reference to FIGS. 2B and 2C and Tables 1 and 2. FIG. The hatching in FIG. 2 (b) shows a state in which charging failure has occurred in the upstream side A1 to A3, and the hatching in FIG. 2 (c) shows that the damper at the downstream outlet of B1 is in a fully closed state. Show.
As shown in FIG. 2 (b), Table 1 shows the case where charging failure occurs in at least one of A1 to A3 on the upstream side using the formulas (2), (3), and (6). dust efficiency eta _1, eta _2, the results of calculation of the eta ₁₂ and the outlet dust amount _{W out} of the electrostatic precipitator 2. Here, _{n a} is 1 to 3, _{n c} is 1, the inlet dust amount _{W in} the electrostatic precipitator 2 93 (mg when the upper limit value _{P 0} is 500 the output of the generator 10 (MW) / ^m is 3 N), the target value _{W P} chimney outlet dust amount is ^{17 (mg / m 3 N)} . Note that the same result as in Table 1 is obtained when a charging failure occurs in at least one of the downstream A1 to A3 sections.

Table 2 shows the dust collection efficiency η using the equations (2), (3), (6) to (9) when the downstream B1 outlet damper is fully closed in addition to the conditions in Table 1. ₁ , η ₂ , η ₁₂ , the outlet dust amount W _out of the electrostatic precipitator 2 and the load suppression value P are calculated.
From Tables 1 and 2, it can be seen that the load suppression value must be set to be smaller than 500 (MW) when the charging failure does not continue on the upstream side and downstream side and occurs in two or more sections. .

Next, consideration will be given to the case where charging failure occurs continuously in the upstream and downstream sections.
First, one of the N sections of the upstream side or downstream side _{n a} compartment of the (8 compartments A1~A4 and B1~B4 in this embodiment) (where, _{n a} ≦ 8) charged defect occurred in In this case, the outlet dust amount W _out of the electrostatic precipitator 2 is the sum of the outlet dust amounts in each section, and is expressed by the following equation (10). Incidentally, without charging defect is continuous in the compartments upstream and downstream, even when the total number of partitions charged defect occurs is n _a, the outlet dust amount W _out of the electrostatic precipitator 2 has the formula (10 ) Is similarly obtained.
Tables 3 and 4 for the case shown in FIG. 2 (b) and FIG. 3 (a), the outlet dust amount of electrostatic precipitator 2 based on the equation (10) where N is the 3 8, _{n a W out} It is the result of having calculated | required. From these tables, the outlet dust amount _{W out} of the electrostatic precipitator 2 obtained using Equation (10) is 15.69 (mg), consistent with the results of the case of the 3 _{n a} in Table 2 You can see that
That is, as shown in FIG. 3A, when the charging failure occurs in a total of three sections without the charging failure being continuous on the upstream side and the downstream side, the outlet dust amount W _out of the electrostatic precipitator 2 is The result is the same as in 2 (b).

On the other hand, the charged defects n _a compartment (where, n _a ≦ 16) generated by, and, n _b position on the upstream side and the downstream side (however, n _b ≦ 8) charged failures occurred in succession In this case, the outlet dust amount W _out2 of the electrostatic precipitator 2 is _expressed by the following equation (11). Incidentally, by comparison with equation (11) Equation _(10), between the _{W out2} and _{W out} it can be seen that there is a relationship expressed by the following equation (12). In this case, W _out2 because must be less than the target value W _P chimney outlet dust amount, load suppression value P rather than the formula (9), is expressed by the following equation (13).

  Here, operation | movement of the electric dust collection system 1a is demonstrated using FIG.4 and FIG.5. FIG. 4A is a block diagram for explaining functions of the electric dust collection system 1a, and FIG. 4B is a flowchart showing an operation procedure of the electric dust collection system 1a. FIG. 5 is a flowchart showing the algorithm of the calculation performed by the calculation means 6. In addition, about the component shown in FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

As shown in FIG. 4 (a), first, the user of this system uses the input means 5 as information on the operating conditions of the electrostatic precipitator 2 as the number of compartments N, the dust collection efficiency η ₀ , and the smoke projection mouth dust. the amount of the target value W _P, when the upper limit value P ₀ of the output of the electric current inlet dust amount W _in and generator 10 of the precipitator 2 is input to the generator output suppression device 3 (arrow a), the control means 4, they Is sent to the storage means 8 for storage (arrow B).
Next, as shown in FIG. 4B, when a charging failure occurs in the electrostatic precipitator 2, the detecting means 2a detects the disconnector 14 in the OFF state and generates an OFF signal (step S10). Then, information indicating the position of the disconnector 14 in the OFF state and an OFF signal are sent to the control means 4 (arrow C). The control means 4 that has received the OFF signal reads information on the operating conditions of the electrostatic precipitator 2 from the storage means 8 (arrow D), and sends this information to the calculation means 6 together with the position information of the disconnector 14 (arrow E). ), The calculation means 6 calculates the load suppression value (step S20).

The calculation means 6 calculates the load suppression value P based on the information received from the control means 4 (steps S30 to S39).
Here, the calculation method of the load suppression value P by the calculating means 6 will be specifically described with reference to FIG. In BL (i, j), the disconnector 14 installed in the j-th section on the upstream side (i = 1) and downstream side (i = 2) is in the ON state (0) and the OFF state (1). It is shown in which state. For example, when the disconnector 14 installed in the section B2 on the upstream side is in the OFF state, the value of BL (1,6) is 1, and the disconnector 14 installed in the section A3 is on the downstream side. In the case of the state, the value of BL (2, 3) is 0.

First, in step S30, BL (i, j) (i = 1 to 2, j = 1 to N) is set to 0 or 1 based on “position information of the disconnector 14 in the OFF state” received from the control means 4. Is substituted. At this _time, n a, the value of _{n b} is 0, i, the value of j is set to 1.
In step S31, when the value of BL (i, j) is 1, that is, when the arithmetic means 6 determines that the j-th disconnector 14 is in the OFF state on the upstream side or the downstream side, the process proceeds to step S32. When the value of BL (i, j) is not 1, that is, when the computing means 6 determines that the j-th disconnector 14 is in the ON state on the upstream side or the downstream side, the process proceeds to step S35.

In step S32, when the value of i is 2 and the value of BL (1, j) is 1, that is, the computing means 6 determines that the j-th disconnector 14 is in the OFF state on the downstream side. then, as the j-th disconnector 14 is turned sequentially with the upstream side and the downstream side in the OFF state, in step S33, the value of _{n b} is increased by one, further, in step S34, the value of _{n a} 1 After the increase, go to step S35. On the other hand, when the value of i is not 2 or the value of BL (1, j) is not 1 in step S32, that is, the j-th disconnector 14 is in the OFF state, and the calculation means 6 judges not to be continuous at the downstream side, in step S34, after the value of n _a is incremented by 1, the process proceeds to step S35.

In step S35, the value of j is incremented by 1. If the value of j is smaller than N in step S36, the process returns to step S31, and if the value of j is N or more, the process proceeds to step S37. Further, in step S37, the value of j is returned to 1 and the value of i is increased by 1. If the value of i is smaller than 2 in step S38, the process returns to step S31. In step S38, the value of i is 2 or more. If so, the process proceeds to step S39.
That is, in steps S31 to S38, it is determined whether each of the first to Nth disconnectors 14 is on or off on the upstream side (i = 1) and the downstream side (i = 2). In addition, the total number (n _a ) of the number of disconnectors 14 in the OFF state and the number (n _b ) in the case where the upstream and downstream sides are continuously in the OFF state are counted.
Thus _n a is determined, by using the _{n b,} in step S39, the outlet dust amount _{W out2} of electrostatic precipitator 2 based on the equation (11) is obtained, further, the expression (13) Based on this, a load suppression value P is obtained.

The load suppression value P obtained in this way is sent from the calculation means 6 to the control means 4 (arrow F) and then sent from the control means 4 to the load control means 7 (arrow G). In step S40, the load suppression value P is sent from the load control means 7 to the generator 10 (arrow H), and the upper limit value of the output of the generator 10 is set to P.
The calculation result by the calculation means 6 is stored in the storage means 8 via the control means 4, and is also output from the output means 9 as appropriate together with other information stored in the storage means 8 (arrow I).

As described above, in the electrostatic precipitator system 1a, the location where the charging failure has occurred is specified based on the detection result of the detecting means 2a, and the amount of dust discharged from the electrostatic precipitator 2 is calculated using equation (11). Is done. That is, in the electric dust collection system 1a of the present invention, the calculation means 6 is configured to estimate the dust collection efficiency of the electric dust collector 2 in consideration of the influence of the charge failure, so that a charge failure occurs in the discharge electrode. Even in this case, the amount of dust discharged from the electric dust collector 2 is accurately predicted.
Furthermore, the load suppression value can be easily and accurately obtained from Expression (13) based on the calculation result of the amount of dust discharged from the electric dust collector 2. And since this load suppression value is set as an upper limit of the output of the generator 10, according to the electric dust collection system 1a of this invention, it is a boiler, without reducing the power generation efficiency of the generator 10 more than necessary. 11 can be appropriately suppressed, and the amount of dust at the smoke outlet can always be kept below the regulation value.

A procedure for obtaining the load suppression value P when the opening degree of the damper at the upstream inlet is different will be described with reference to FIGS. 3 and 6 are schematic views in which a part of the electrostatic precipitator 2 is enlarged.
In the electrostatic precipitator 2 shown in FIG. 6, if a charging failure occurs at several locations in the 2N section, the outlet dust amount W _out3 of the electrostatic precipitator 2 is determined so that the charging failure occurs at the upstream side and the downstream side. Regardless of whether or not they are continuous, the ratio of the flue gas distributed to the upstream inlet of each of the N sections is expressed by the following equation (14), where α _k (k ≦ N).
In this case, W _out3 from it must be less than the target value W _P chimney outlet dust amount, load suppression value P rather than the formula (13), it is expressed by the following equation (15). In Equation (14), the values of η _k1 and η _k2 for k where no charging failure has occurred are 0.7, and the values of η _k1 and η _k2 for k where charging failure has occurred are 0. is there.

As shown in FIG. 6 (a), when the opening degree of the damper at the upstream side is 90 degrees for A1 to A1, 0 degree for B1, 50 degrees for B2, 60 degrees for B3 and B4, the flue gas is As shown in FIG. 6 (b), it is distributed to each section. However, the ratio of the flue gas that passes through the damper is assumed to be proportional to the opening of the damper, assuming that 0 degree and 90 degree are 0% and 100%, respectively. That is, the value of the flue gas ratio α _k distributed to each section is, for example, 0.17 (= 100% / 590%) for A1 to A4.

Table 6 shows the distribution ratio of flue gas to each section of A1 to B4 and the values of k and α _k . Tables 7 and 8 show the amount of dust discharged from the electric dust collector 2 _Wout3 obtained based on the equation (14) for the cases shown in FIGS. 3 (a) and 3 (b).
Looking at Tables 7 and 8, in FIG. 3 (a) and 3 outlet dust amount of the electrostatic precipitator 2 in the case of (b) _{W out3} respectively 18.33 (mg) and 26.08 (mg) Yes, the difference between the two is 7.75 (mg).
When the load suppression value P in the case of FIG. 3A and FIG. 3B is calculated from W _out3 thus obtained based on the equation (15), 464 (MW) and 326 (MW) and Become.
That is, if charging failure occurs continuously at the upstream side and the downstream side in a place where the distribution amount of smoke is large, the dust collection performance of the electrostatic precipitator 2 is remarkably reduced, and the load suppression value also increases accordingly. I understand that.

As already described, the electric dust collection system 1b of the present embodiment has a structure suitable for the case where the flue gas is not evenly distributed to each section. Hereinafter, the structure and operation of the electric dust collection system 1b will be described with reference to FIGS.
FIG. 7A and FIG. 7B are a block diagram for explaining the function of the electric dust collection system 1b and a flowchart showing its operation procedure. FIG. 8 is a flowchart showing an algorithm of calculation performed by the calculation means 6 of the electric dust collection system 1b.
As shown to Fig.7 (a), the electrostatic dust collection system 1b of a present Example has the structure provided with the detection means 2b which detects the opening degree of a damper in the electrical dust collection system 1a of Example 1. FIG. . And based on the opening degree of the damper which the detection means 2b detected, the calculating means 6 calculates the ratio of the flue gas distributed to each division of the electric dust collector 2, It is characterized by the above-mentioned.

First, the user of this system uses the input means 5 as information on the operating conditions of the electrostatic precipitator 2 as the number of sections N, the dust collection efficiency η ₀ , the target value W _P of the smoke projection mouth dust amount, the electrostatic dust collector If the upper limit value P ₀ of the output of the inlet dust amount W _in and generator 10 of the vessel 2 is input to the generator output suppression device 3 (arrow a), the control unit 4 may send the information in the storage unit 8 stores (Arrow B).
Next, as shown in FIG. 7B, when a charging failure occurs in the electrostatic precipitator 2, the detecting means 2a detects the disconnector 14 in the OFF state and generates an OFF signal. 2b detects the opening degree of the damper (step S10), and sends information indicating the position of the disconnector 14 in the OFF state and information relating to the OFF signal and the opening degree of the damper to the control means 4 (arrow C). The control means 4 that has received the OFF signal reads information on the operating conditions of the electrostatic precipitator 2 from the storage means 8 (arrow D), and calculates this information together with the position information of the disconnector 14 and the information on the opening of the damper. It is sent to the means 6 (arrow E), and the calculation means 6 is made to calculate the load suppression value (step S20).

The calculating means 6 calculates the ratio α _k (k ≦ N) of the flue gas distributed to each section based on the information about the opening of the damper detected by the detecting means 2b, and then detected by the detecting means 2a. A load suppression value P is calculated based on the position information of the disconnector 14 in the OFF state (steps S30 to S39).
Here, a method for calculating the load suppression value P by the calculation means 6 will be specifically described with reference to FIG.

First, in step S30, as described above, α _k is calculated based on “information on the opening degree of the damper” received from the control means 4, and is substituted for AL (j) (j = 1 to N), respectively. .
In step S31, 0 or 1 is assigned to BL (i, j) (i = 1 to 2, j = 1 to N) based on “position information of disconnector 14 in the OFF state” received from the control means 4, respectively. Η ₀ is substituted into EK (i) (i = 1 to 2). At this time, the value of W _out3 is 0, and the values of i and j are 1.

In step S32, when the value of BL (i, j) is 1, that is, when the computing means 6 determines that the j-th disconnector 14 is in the OFF state on the upstream side or downstream side, EK ( After the value of i) is set to 0, the process proceeds to step S34. On the other hand, when BL (i, j) is not 1, that is, when the computing means 6 determines that the j-th disconnector 14 is in the ON state on the upstream side or downstream side, the process bypasses step S33 and proceeds to step S34. .
In step S34, the value of i is incremented by 1. If the value of i is smaller than 2 in step S35, the process returns to step S32. If the value of i is 2 or more, the process proceeds to step S36.

Using EK (1) and EK (2) obtained in this way, in step S36, calculation is performed for the case where k is 1 in equation (14). Thereafter, in step S37, the value of i is returned to 1, the values of EK (1) and EK (2) are set to η ₀ , and the value of j is increased by 1. In step S38, if the value of j is smaller than N, the process returns to step S32. If the value of j is N or more, the process proceeds to step S39. Thus, when the step S32~ step S36 is repeated N times, will be k in Equation (14) is made a calculation for the case of 1 to N, the outlet dust amount _{W out3} of the electrostatic precipitator 2 is calculated It is done.
By using W _out3 obtained in this way, in step S39, the load suppression value P is obtained based on Expression (15).

The load suppression value P is sent from the calculation means 6 to the control means 4 (arrow F) and further sent from the control means 4 to the load control means 7 (arrow G), as in the case of the electric dust collection system 1a. In step S40, the load suppression value P is sent from the load control means 7 to the generator 10 (arrow H), and the upper limit value of the output of the generator 10 is set to P.
The calculation result by the calculation means 6 is stored in the storage means 8 via the control means 4, and is also output from the output means 9 as appropriate together with other information stored in the storage means 8 (arrow I).

Thus, in the electrostatic dust collection system 1b, the ratio of the flue gas distributed to each section of the electrostatic precipitator 2 and the location where the charging failure occurs is specified based on the detection results of the detection means 2a and 2b. The load suppression value P corresponding to the occurrence pattern of the charge failure is calculated by the calculation means 6 based on (14) and the expression (15), and the upper limit value of the output of the generator 10 is set by the load control means 7. It has become.
Therefore, according to the electrostatic precipitator system 1b of the present invention, even if the charging failure occurs in the discharge electrode of the electrostatic precipitator 2 and the smoke is not evenly distributed to each section, the generator 10 Without reducing the power generation efficiency more than necessary, the generation of soot in the boiler 11 can be appropriately suppressed, and the amount of soot at the smoke outlet can always be kept below the regulation value.

In the present embodiment, the opening degree of the damper is detected by the detecting means 2b, but the electric dust collection system of the present invention is not limited to such a structure. For example, instead of providing the detection means 2b, the ratio of the smoke distribution to each section of the electrostatic precipitator 2 (corresponding to α _k in the equation (14)) is input from the input means 5 in advance and stored in the storage means 8 This information is read from the storage means 8 and sent to the calculation means 6 via the control means 4 when the calculation means 6 calculates the amount of dust discharged from the electric dust collector 2. May be. In this case, since the load suppression value is calculated from the equations (14) and (15) by the computing means 6, the above-described actions and effects are similarly exhibited.

The invention described in claim 1 of the present invention is not limited to the power plant, it can be installed in a place where there is a need to collect the dust contained in the combustion exhaust gas from the boiler.

DESCRIPTION OF SYMBOLS 1a, 1b ... Electric dust collection system 2 ... Electric dust collector 2a, 2b ... Detection means 3 ... Soot generation suppression device 4 ... Control means 5 ... Input means 6 ... Calculation means 7 ... Load control means 8 ... Storage means 9 ... Output Means 10 ... Generator 11 ... Boiler 12 ... Discharge electrode 13 ... Chimney 14 ... Disconnector 15 ... Rectifier

Claims (1)

An electric dust collection system for collecting dust contained in combustion exhaust gas generated in a boiler,
An electric dust collector in which a plurality of sections are formed, and a charging circuit composed of a discharge electrode and a disconnector is installed for each section,
A charging failure detection means that is installed in the electrostatic precipitator and detects the ON-OFF state of the disconnector for each section;
Storage means for storing information on operating conditions of the electrostatic precipitator;
A computing means for calculating an outlet dust amount of the electrostatic precipitator based on the information stored in the storage means and a pattern of the ON-OFF state of the disconnector;
Load control means for suppressing the generation of dust in the boiler based on the amount of dust at the outlet ,
The compartments are formed in N pieces so as to form a pair at locations upstream and downstream with respect to the dust flow,
Of this the 2N compartment, if with charge defect occurs in n _a number, successively with the upstream side and the downstream side in the compartment of n _b pair charged failure occurs,
The inlet dust amount of the dust collector and W _in, as eta ₀ a dust collecting efficiency of the normal operation when the discharge electrode of said calculating means, the outlet dust amount W of the electrostatic precipitator according to the following equation An electric dust collection system characterized by calculating _out2 .

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