JP2013130370A - Reheat steam temperature control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reheat steam temperature control device with improved controllability and operational reliability, configured to allow a simple control logic with shared functions.SOLUTION: A first path, a second path, and a third path are formed in a flue. A superheater and a first path gas distribution damper are arranged in the first path. A first stage reheat combustor and a second path gas distribution damper are arranged in the second path. A second stage reheat combustor and a third path gas distribution damper are arranged in the third path. A damper for restoring opening of a first or second path gas distribution damper within a reference opening range even when the opening of the first and second path gas distribution dampers deviate from the reference opening range.

Description

  The present invention relates to a reheat steam temperature control device that controls a reheat steam temperature using a gas distribution damper, and in particular, divides the flue of a rear heat transfer section into at least three first to third paths, The superheater and the first pass gas distribution damper are arranged in one pass, the first stage reheater and the second pass gas distribution damper are arranged in the second pass, and the second stage reheater and the second pass are arranged in the third pass. The present invention relates to a reheat steam temperature control device of a two-stage reheat system in which a three-pass gas distribution damper is arranged to control the temperature of the first-stage reheat steam temperature and the second-stage reheat steam temperature.

  As this type of boiler steam temperature control device, there is a proposal as described in, for example, Japanese Patent Laid-Open No. 2000-161607 (Patent Document 1). This proposed boiler steam temperature control device is divided into two gas flow paths, and is suitable when the steam temperature fluctuates rapidly. However, in order to further improve power generation efficiency, the number of gas flow paths is increased to three or more. There has been a problem that the cooperation between the dampers when divided is not considered, and the controllability of the steam temperature deteriorates due to the mutual interference between the dampers.

  FIG. 13 is a view showing the opening state of the distribution damper at the reference opening position (neutral) of the boiler device in the one-stage reheating system, and FIG. 14 is an operation of the distribution damper when raising the reheat steam temperature in the boiler device. FIG. 15 is a diagram for explaining the operation of the distribution damper when the reheat steam temperature is lowered in the boiler device.

  As shown in FIG. 13, in the conventional one-stage reheating boiler apparatus, the inside of the flue 1305 through which the combustion gas G generated by combustion circulates is divided into two paths, a first path 1306 and a second path 1307. A horizontal superheater (SH) 1301 is installed upstream of the first path 1306 in the combustion gas flow direction, and a horizontal reheater (RH) 1302 is installed upstream of the second path 1307 in the combustion gas flow direction. is set up. Further, one first pass gas distribution damper 1303 is disposed downstream of the superheater (SH) 1301 in the combustion gas flow direction, and one second pass gas is disposed downstream of the reheater (RH) 1302 in the combustion gas flow direction. A distribution damper 1304 is arranged.

  Normally, the reheat steam temperature is controlled by adjusting the gas flow rate of the combustion gas G flowing through the two paths 1306 and 1307, and the fluctuations of the main steam temperature caused thereby are adjusted by adjusting the flow rates of fuel, feed water and spray. Controlled. Therefore, the two gas distribution dampers 1303 and 1304 only have to control the reheat steam temperature.

  It is assumed that the first two gas distribution dampers 1303 and 1304 have settled at the position of the reference opening shown in FIG. When the reheat steam temperature falls below the set temperature, as shown in FIG. 14, the second pass gas distribution damper 1304 on the reheater (RH) 1302 side is opened, and conversely, the first on the superheater (SH) 1301 side is opened. The pass gas distribution damper 1303 was closed and the flow rate of the combustion gas flowing on the reheater (RH) 1302 side was increased to raise the reheat steam temperature.

  On the other hand, when the reheat steam temperature exceeds the set temperature, the operation is the reverse of the above. That is, as shown in FIG. 15, the first pass gas distribution damper 1303 on the superheater (SH) 1301 side and the second pass gas distribution damper 1304 on the reheater (RH) 1302 side sandwich the reference opening position shown in FIG. The reheat steam temperature was lowered by moving the same amount in the opposite direction.

In a thermal power plant, with the aim of improving the power generation efficiency and reducing the CO ₂ emission amount per unit energy, the steam temperature is increased and the efficiency is increased by increasing the pressure. The current Super Super Critical (USC) plant has a main steam temperature of about 600 ° C, but an advanced super super critical pressure (A-USC) plant that aims for higher power generation efficiency has a higher main steam temperature and reheat. The target is steam temperature.

In order to increase the efficiency of this thermal power plant, a two-stage reheating boiler apparatus is being studied. FIG. 16 is a schematic configuration diagram showing a part of the boiler apparatus of the two-stage reheating method studied previously.
As shown in FIG. 16, the rear horizontal portion of the flue 1305 is divided into three paths, a first path 1306, a second path 1307, and a third path 1308, upstream of the first path 1306 in the combustion gas flow direction. A horizontal superheater 1601 is installed on the side, a horizontal first stage reheater 1602 is installed upstream of the second pass 1307 in the combustion gas flow direction, and upstream of the third pass 1308 in the combustion gas flow direction. A horizontal second stage reheater 1603 is installed. Also, one first pass gas distribution damper 1604 is disposed downstream of the superheater 1601 in the combustion gas flow direction, and one second pass gas distribution damper 1605 is disposed downstream of the first stage reheater 1602 in the combustion gas flow direction. Is arranged, and one third pass gas distribution damper 1606 is arranged downstream of the second stage reheater 1603 in the combustion gas flow direction.

  The first stage reheat steam temperature and the second reheat steam temperature are controlled by three gas distribution dampers 1604, 1605 and 1606. In other words, the flow rate of the gas flowing through the second path 1307 (first stage reheater 1602) is adjusted to control the first stage reheat steam temperature and flow through the third path 1308 (second stage reheater 1603). The gas flow rate is adjusted to control the second stage reheat steam temperature. The first-pass gas distribution damper 1604 adjusts the flow rate of the gas flowing through the first pass 1306 (superheater 1601) so as to compensate for the excess or deficiency of the first-stage reheat steam temperature and the second-stage reheat steam temperature. The main steam temperature is controlled by adjusting the flow rates of the fuel, feed water, and spray as in the case of the one-stage reheat boiler.

JP 2000-161607 A

  The two-stage reheat boiler apparatus shown in FIG. 16 has the same basic concept as the above-described one-stage reheat boiler apparatus, except that the reheater (RH) has only two stages. As described above, the same applies to the two passes and the three passes, but the damper opening degree for realizing a certain gas flow rate balance is not uniquely determined.

  That is, it is assumed that the flow rates of the combustion gas flowing through the three paths 1306, 1307, and 1308 are the same at the neutral position shown in FIG. Here, as shown in FIG. 17, even when all the gas distribution dampers 1604, 1605, 1606 are opened, or all the gas distribution dampers 1604, 1605, 1606 are opened, the three passes 1306. , 1307, and 1308 have an opening with the same gas flow rate.

  For example, when the first stage reheat steam temperature decreases in the state of FIG. 17, the second pass gas distribution damper 1605 has already been fully opened, and therefore the third pass gas distribution damper 1606 and the first pass gas distribution damper 1604 are closed. Although the gas flow rate flowing through the second path 1307 (first stage reheater 1602) can be indirectly increased, the second path gas distribution damper 1605 is opened to open the second path 1307 (first stage reheat). Since the flow rate of gas flowing through the vessel 1602) cannot be increased, the controllability of the first stage reheat steam temperature is reduced.

  In addition, as described above, the main steam temperature can be controlled by adjusting the flow rates of fuel, feed water, and spray in the same manner as in the one-stage reheating boiler device. In some cases, as shown in FIG. There is also a possibility that the pass gas distribution damper 1605 and the third pass gas distribution damper 1606 are opened and the first pass gas distribution damper 1604 is closed and stabilized. However, when the first stage reheat steam temperature and the second stage reheat steam temperature rise in this state, the first stage reheat steam temperature and the second stage reheat steam temperature are no longer in the gas distribution dampers 1604, 1605, 1606. Cannot be controlled.

  Another factor that makes it difficult to control the gas distribution damper is the nonlinearity of the damper. The gas flow rate is adjusted by the damper opening, but the opening and the gas flow rate are not in a proportional relationship. Even if the opening is manipulated by the same amount, the gas flow rate does not always change by the same amount.

  Even when the degree of control does not become impossible as described above, when the opening degree is largely opened as shown in FIG. 17, the gas flow rate does not change so much even if the opening degree is changed. Conversely, when the opening is extremely small, the sensitivity of the damper becomes too high, and it becomes difficult to adjust to the required gas flow rate. Therefore, if the control system settings are adjusted to be optimal at the position of the reference opening (neutral), the gas distribution damper should be placed around the position of the reference opening as much as possible for the best controllability. Should be manipulated.

However, in the case of 3 passes shown in FIGS. 16 to 18, as in the case of 2 passes, the operation cannot be simply performed in the reverse direction based on the position of the reference opening. Is likely to deviate from the optimal position and fall into an uncontrollable state as described above.
As a countermeasure, there is a problem in that each gas distribution damper requires an operation for returning it to the reference opening position with a slower movement than the normal control, resulting in complicated control.

  The object of the present invention is that the second pass gas distribution damper and the third pass gas distribution damper need only control the reheat steam temperature, the functions can be shared, the control logic is simplified, and the controllability and operational reliability are improved. An object of the present invention is to provide a reheat steam temperature control device capable of achieving the above.

In order to achieve the above object, the present invention provides:
Dividing the flue of the rear heat transfer section into a first pass, a second pass, and a third pass extending in the direction of combustion gas flow by the partition wall,
A superheater is disposed upstream of the first pass in the combustion gas flow direction, and a first pass gas distribution damper is disposed downstream of the combustion gas flow direction;
A first stage reheater is disposed upstream of the second pass in the combustion gas flow direction, a second pass gas distribution damper is disposed downstream of the combustion gas flow direction, and the second pass gas distribution damper is operated to operate the second pass gas distribution damper. The first stage reheat steam temperature is controlled by adjusting the flow rate of the combustion gas flowing through the second path,
A second stage reheater is disposed upstream of the third pass in the combustion gas flow direction, a third pass gas distribution damper is disposed downstream of the combustion gas flow direction, and the third pass gas distribution damper is operated to The present invention is directed to a reheat steam temperature control device that controls the second stage reheat steam temperature by adjusting the flow rate of the combustion gas flowing through the third pass.

And the first means of the present invention is:
A first pass gas for returning the opening degree of the first pass gas distribution damper to the reference opening range when the opening degree of the first pass gas distribution damper deviates from a predetermined reference opening range of the damper. A distribution damper return damper is provided in the first path,
A second pass gas for returning the opening degree of the second pass gas distribution damper to the reference opening range when the opening degree of the second pass gas distribution damper deviates from a predetermined reference opening range of the damper. Distribution damper return damper is provided in the second path,
Third pass gas distribution damper return for returning the opening degree of the third pass gas distribution damper to the reference opening range when the opening degree of the third pass gas distribution damper is out of a predetermined reference opening range. The damper is provided in the third path.

According to a second means of the present invention, in the first means,
The gas distribution damper and the return damper are provided in parallel with the combustion gas flow direction. According to a third means of the present invention, in the first means,
The return dampers are provided on the downstream side or the upstream side in the combustion gas flow direction with respect to the gas distribution dampers.

  The present invention is configured as described above, and the second pass gas distribution damper and the third pass gas distribution damper need only control the reheat steam temperature, and the functions are shared, so that the control logic is simplified and the control is performed. And operational reliability can be improved.

1 is a schematic configuration diagram of a two-stage reheating boiler device according to a first embodiment of the present invention. It is a figure for demonstrating the change of each steam temperature when the 1st stage reheat steam temperature rises in this embodiment, and operation of each damper. It is a figure for demonstrating the change of each steam temperature when the 2nd stage reheat steam temperature rises in this embodiment, and operation of each damper. It is a figure for demonstrating the change of each steam temperature, and operation of each damper when both the 1st stage reheat steam temperature and 2nd stage reheat steam temperature rise simultaneously in this embodiment. It is a figure which shows the opening degree state of each distribution damper in a reference position in this embodiment. It is a figure showing the state where the 3rd pass gas distribution damper shifted from the standard opening position. It is a figure which shows the state which returned the 3rd pass gas distribution damper to the reference | standard opening position by the return damper. It is a figure which shows the case where the gas distribution damper has shifted | deviated from the reference opening position even after the fluctuation | variation of steam temperature settled. It is a figure which shows the case where the return damper corresponding to the gas distribution damper was operated so that a gas distribution damper might return to a reference opening position after the fluctuation | variation of steam temperature was settled. It is a figure which shows the case which returned the opening degree of the gas distribution damper to the reference | standard opening position using the return damper. It is a figure which shows the other case which returned the opening degree of the gas distribution damper to the reference | standard opening position using the return damper. It is a principal part expansion schematic block diagram for demonstrating the reheat steam temperature control apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the opening state of the distribution damper in the reference | standard opening position of the boiler apparatus in the conventional one-stage reheating system. It is a figure for demonstrating operation of a distribution damper when raising reheat steam temperature in the boiler apparatus. It is a figure for demonstrating operation of the distribution damper when reducing the reheat steam temperature in the boiler apparatus. It is a schematic block diagram which shows a part of boiler apparatus of the two-stage reheating system examined previously. It is a figure for demonstrating the problem of the boiler apparatus of the two-stage reheating system. It is a figure for demonstrating the problem of the boiler apparatus of the two-stage reheating system.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a two-stage reheating boiler apparatus according to a first embodiment of the present invention.
First, the schematic configuration of the boiler apparatus 101 according to the present embodiment will be described with reference to FIG.

  As shown in the figure, water supply 108 supplied by a water supply pump 51 is divided into a economizer 52, a water wall 53, a horizontal primary superheater 102, a suspended secondary superheater 54, a suspended tertiary superheater 55, Super high pressure steam turbine 56, first stage horizontal reheater 103, first stage suspended reheater 57, high pressure steam turbine 58, second stage horizontal reheater 104, second stage suspended reheater 59 The intermediate pressure steam turbine 60, the low pressure steam turbine 61, the condenser 62, and the feed water pump 51 are circulated.

  On the other hand, a predetermined amount of coal supplied from the coal bunker 63 is charged into the pulverizer 65 by the coal feeder 64, and the fuel (pulverized coal) 107 generated by pulverization in the pulverizer 65 is used as the water wall. It is injected from a burner 66 installed in a furnace constituted by 53 and burned in the furnace.

  The combustion gas G generated by this combustion and the feed water 108 are converted into the economizer 52, the water wall 53, the horizontal primary superheater 102, the suspended secondary superheater 54, the suspended tertiary superheater 55, Heat exchange is performed by the first-stage horizontal reheater 103, the first-stage suspended reheater 57, the second-stage horizontal reheater 104, and the second-stage suspended reheater 59, and the high-temperature and high-pressure main steam is exchanged. In addition, it has a mechanism to obtain reheat steam.

  The steam pipe connecting the secondary superheater 54 and the tertiary superheater 55 is provided with a spray 109a for adjusting the steam temperature, and the horizontal primary heater 102 and the suspended secondary superheater 54 are connected to each other. A spray 109b for adjusting the steam temperature is installed in the steam pipe to be connected.

  Inside the flue 67 of the rear heat transfer section of the boiler device 101, the three paths of the first path 68, the second path 69, and the third path 70 are parallel to each other along the flow direction of the combustion gas G. Is formed. A horizontal primary superheater (1SH) 102 is installed upstream of the first pass 68 in the combustion gas flow direction, and a first-stage horizontal reheat is installed upstream of the second pass 69 in the combustion gas flow direction. The second stage horizontal reheater (1RH (2)) 104 is installed upstream of the third path 70 in the combustion gas flow direction. A economizer (ECO) 52 is installed downstream of the superheater 102 and the reheaters 103 and 104 in the combustion gas flow direction.

  The downstream side in the combustion gas flow direction of the economizer (ECO) 52 of the first path 68 is further divided into two paths. The first path gas distribution damper 115 is disposed in one path, and the other path is disposed in the other path. A first pass gas distribution damper return damper 124 is disposed. Therefore, the first pass gas distribution damper 115 and the first pass gas distribution damper return damper 124 are provided in parallel with the combustion gas flow direction.

  The damper opening degree of the first pass gas distribution damper 115 is measured by a damper opening degree sensor 118, and the damper opening degree of the first pass gas distribution damper return damper 124 is measured by a damper opening degree sensor 127.

The downstream side of the economizer (ECO) 52 in the second path 69 in the combustion gas flow direction is further divided into two paths. A second path gas distribution damper 113 is disposed in one path, and the other path is disposed in the other path. A second pass gas distribution damper return damper 122 is arranged. Therefore, the second pass gas distribution damper 113 and the second pass gas distribution damper return damper 122 are provided in parallel with the combustion gas flow direction.
The damper opening degree of the second pass gas distribution damper 113 is measured by a damper opening degree sensor 116, and the damper opening degree of the second pass gas distribution damper return damper 122 is measured by a damper opening degree sensor 125.

The downstream side in the combustion gas flow direction of the economizer (ECO) 52 of the third path 70 is further divided into two paths. A third path gas distribution damper 114 is disposed in one path, and the other path is disposed in the other path. A third pass gas distribution damper return damper 123 is arranged. Therefore, the third pass gas distribution damper 114 and the third pass gas distribution damper return damper 123 are provided in parallel with the combustion gas flow direction.
The damper opening degree of the third pass gas distribution damper 114 is measured by a damper opening degree sensor 117, and the damper opening degree of the third pass gas distribution damper return damper 123 is measured by a damper opening degree sensor 126.

  In the figure, reference numeral 106 is a main steam temperature control unit, 112 is a reheat steam temperature control unit, 119, 120 and 121 are return damper control units, and 128 is a return damper operation unit.

  The main steam temperature 105 is controlled by the main steam temperature control unit 106 by operating the flow rate of the fuel 107, the flow rate of the feed water 108, the spray 109b and the spray flow rate of the spray 109a.

  The first-stage reheat steam temperature 110 and the second-stage reheat steam temperature 111 are determined by the second pass gas distribution damper 113, the third pass gas distribution damper 114, and the first pass gas according to a control signal from the reheat steam temperature control unit 112. The three gas distribution dampers of the distribution damper 115 are operated and controlled.

  Further, the damper opening degree of the three gas distribution dampers 113, 114, 115 is measured by the respective damper opening degree sensors 116, 117, 118, and the second-pass gas distribution is performed by the return damper control units 119, 120, 121. The damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 are operated to adjust the reference opening.

  More specifically, the current damper opening of the second pass gas distribution damper 113 is measured by the damper opening sensor 116, and the result is sent to the return damper control unit 119. In the return damper control unit 119, the current damper opening of the second pass gas distribution damper 113 is set to a reference opening range of the second pass gas distribution damper 113 (the reference opening range is the reference opening). A determination is made as to whether or not the position is within the vicinity of the reference opening position determined within a range of, for example, ± 5% around the position. On the other hand, if it is off, a deviation amount from the reference opening range is calculated.

  On the other hand, the current damper opening of the second pass gas distribution damper return damper 122 is measured by the damper opening sensor 125, and the result is sent to the return damper calculation unit 128.

  The return damper calculation unit 128 evaluates the opening degrees of the second pass gas distribution damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124, and returns the second pass gas distribution damper return. The return damper control units 119, 120, and 121 are instructed so that the dampers 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 have openings close to neutral.

  For example, if all of the second pass gas distribution damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 are open, the second pass gas distribution damper return damper 124 is open. 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 are all closed, and conversely, the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are closed. If all of the first pass gas distribution damper return dampers 124 are closed, the second pass gas distribution damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 are used. Instruct to open any of them.

  If the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are fully open and the first pass gas distribution damper return damper 124 is neutral, the second pass gas distribution damper return damper 122, the third The pass gas distribution damper return damper 123 and the first pass gas distribution damper return damper 124 are closed, the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are opened from the neutral position, and the first pass gas distribution damper return is returned. The damper 124 is adjusted to be closed from the neutral position. That is, it is preferable that the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are fully opened, and the sum of deviations from the neutral of the first pass gas distribution damper return damper 124 is minimized.

  Such opening degree control is similarly performed in the other third pass gas distribution damper return damper 123 and the first pass gas distribution damper return damper 124.

  The reheat steam temperature control unit 112 uses the second pass gas distribution damper 113, the third pass gas distribution damper 114, and the first pass gas distribution damper 115 to perform the first stage reheat steam temperature 110 and the second stage reheat steam. The temperature 111 is controlled.

  The return damper control unit 119 measures the opening degree of the second pass gas distribution damper 113 with the damper opening degree sensor 116 (with a correction signal from the return damper calculation unit 128), and the second pass gas distribution damper 113 is neutral. The second pass gas distribution damper return damper 122 is operated so that

  The return damper control unit 120 measures the opening degree of the third pass gas distribution damper 114 with the damper opening degree sensor 117, and the third pass gas distribution damper return damper 123 so that the third pass gas distribution damper 114 becomes neutral. To operate.

  The return damper control unit 121 measures the opening degree of the first pass gas distribution damper 115 with the damper opening degree sensor 118, and the first pass gas distribution damper return damper 124 so that the first pass gas distribution damper 115 becomes neutral. To operate.

  The return damper calculation unit 128 uses the damper opening degree sensors 125, 126, and 127 to determine the opening degrees of the second pass gas distribution damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124, respectively. The second pass gas distribution damper return damper 122, the third pass gas distribution damper return damper 123, and the first pass gas distribution damper return damper 124 are pulled back so as to have an easily controlled opening (a correction signal is generated). ).

Next, specific damper adjustment will be described with reference to FIGS.
As shown in FIG. 1, the main steam temperature (SOT) 105 is controlled by the main steam temperature control unit 106 by adjusting the flow rate of the fuel 107 and the flow rate of the feed water 108. Furthermore, the transient flow of the main steam temperature (SOT) 105 is controlled by operating the spray flow rate of the sprays 19a and 19b. These are operated independently of the gas distribution dampers 113, 114, 115.

  Regarding the operation method of the gas distribution dampers 113, 114, 115, the basic concept is the same as the conventional method, and the first stage reheat steam temperature (ROT (1)) 110 and the second stage reheat steam temperature (ROT). (2)) Operate the flow rate of the combustion gas flowing through the second path 69 (first stage reheater 103) and the third path 70 (second stage reheater 104) so that 111 becomes a predetermined value. To do.

Unless the flow rate of the fuel 107 changes, if the combustion gas G does not flow at the same flow rate, for example, the furnace draft will rise or fall too much, so the second pass 69 (first stage reheater 103) and the third pass It is necessary to adjust the flow rate of the combustion gas flowing through the first path 68 (superheater 102) for the fluctuation amount of the flow rate of the combustion gas flowing through 70 (second stage reheater 104).
Although the operation of the gas distribution dampers 113, 114, and 115 affects the main steam temperature 105, as described above, the main steam temperature 105 causes the fuel 107, the feed water 108, and the sprays 19a and 19b to pass through the gas distribution damper. The main steam temperature can be controlled to a predetermined temperature by operating independently of 113, 114, and 115.

  FIG. 2 is a diagram for explaining the change of each steam temperature and the operation of each damper when the first stage reheat steam temperature (ROT (1)) 110 rises in this embodiment, and FIG. FIG. 4 is a diagram for explaining the change of each steam temperature and the operation of each damper when the second stage reheat steam temperature (ROT (2)) 111 rises. FIG. 4 shows the first stage reheat steam temperature in this embodiment. It is a figure for demonstrating the change of each steam temperature, and operation of each damper when both (ROT (1)) 110 and 2nd stage reheat steam temperature (ROT (2)) 111 rise simultaneously.

  As shown in FIG. 2, when the first-stage reheat steam temperature (ROT (1)) 110 rises, the opening degree of the second pass gas distribution damper (R (1) D) 113 is closed, and in conjunction with this, The one-pass gas distribution damper (SD) 115 is opened. Under the influence, the main steam temperature (SOT) 105 rises, but the main steam temperature (SOT) 105 is controlled to a predetermined value by adjusting the flow rates of the fuel 107, the feed water 108, and the sprays 19a and 19b. In this way, the first stage reheat steam temperature (ROT (1)) 110 and the main steam temperature (SOT) 105 can be adjusted to constant values.

  In practice, the second-stage reheat steam temperature 111 is also affected and fluctuates. However, for the sake of simplicity, the second-pass gas distribution damper (R (1) D) 113 and the first-pass gas distribution damper (SD) are used here. ) 115 was operated ideally and was described as having no effect on the second stage reheat steam temperature 111.

  As shown in FIG. 3, when the second-stage reheat steam temperature (ROT (2)) 111 rises, the opening degree of the third pass gas distribution damper (R (2) D) 114 is closed, and in conjunction with this, The one-pass gas distribution damper (SD) 115 is opened. In this case as well, the main steam temperature (SOT) 105 rises due to the influence, but the main steam temperature (SOT) 105 is controlled to a predetermined value by adjusting the flow rates of the fuel 107, the feed water 108, and the sprays 19a and 19b. In this way, the second stage reheat steam temperature (ROT (2)) 111 and the main steam temperature (SOT) 105 can be adjusted to constant values.

  As shown in FIG. 4, when both the first stage reheat steam temperature (ROT (1)) 110 and the second stage reheat steam temperature (ROT (2)) 111 rise simultaneously, the second pass gas distribution damper ( R (1) D) 113 and the third pass gas distribution damper 114 are both closed to adjust the temperature, and the first pass gas distribution damper (SD) 115 is operated by the temperature that is not offset by the operation. , Cancel the temperature that was not offset. In this case, the main steam temperature (SOT) 105 fluctuates due to the influence, but the main steam temperature (SOT) 105 is controlled to a predetermined value by adjusting the flow rates of the fuel 107, the feed water 108, and the sprays 19a and 19b. In this way, the first stage reheat steam temperature (ROT (1)) 110, the second stage reheat steam temperature (ROT (2)) 111, and the main steam temperature (SOT) 105 are adjusted to constant values. Can do.

  FIG. 5 is a view showing the opening state of each distribution damper at the reference position (neutral) in the present embodiment, FIG. 6 is a view showing a state where the third pass gas distribution damper 114 is deviated from the reference opening position, and FIG. It is a figure which shows the state which returned the 3rd pass gas distribution damper 114 to the standard opening position by the damper 123 for the 3rd pass gas distribution damper return.

  Assuming that the damper opening shown in FIG. 5 is the reference opening, if this operation is continued, for example, as shown in FIG. 6, due to the influence of accumulation of control errors, differences in coal types, nonlinearity of the damper, etc. There is a possibility that the three-pass gas distribution damper 114 is shifted from the reference opening position and balances, and there is a problem that the controllability deteriorates when the gas distribution damper is out of the reference opening position as described above. Therefore, as shown in FIG. 7, the third pass gas distribution damper return damper 123 corresponding to the third pass gas distribution damper 114 is operated to return the third pass gas distribution damper 114 to the reference opening position.

  The same applies to other dampers, which will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram illustrating a case where the gas distribution damper is deviated from the reference opening position even after the fluctuation of the steam temperature is settled. FIG. 9 is a diagram illustrating the case where the gas distribution damper is moved to the reference opening position after the fluctuation of the steam temperature is settled. It is a figure which shows the case which operated the return damper corresponding to the gas distribution damper so that it may return.

  As shown in FIG. 8, it is assumed that the first-stage reheat steam temperature (ROT (1)) 110 and the second-stage reheat steam temperature (ROT (2)) 111 vary. Accordingly, the second pass gas distribution damper (R (1) D) 113 and the third pass gas distribution damper (R (2) D) 114 are operated to adjust the temperature, and the temperature components that are not offset by the operation are adjusted. Only the first pass gas distribution damper (SD) 115 is operated.

  Ideally, all the gas distribution dampers 113, 114, and 115 should be stationary at the reference opening position when the fluctuation of the steam temperature is settled, but in practice, as shown in FIG. There is a possibility that one or more gas distribution dampers (gas distribution dampers 113, 114, and 115 in the example of FIG. 8) deviate from the reference opening position (dotted line position) and stop. If nothing is dealt with, controllability deteriorates.

  Therefore, as shown in FIG. 9, the return dampers 122, 123, 124 provided corresponding to the respective gas distribution dampers 113, 114, 115 are operated more slowly than the operation of the gas distribution dampers 113, 114, 115. The gas distribution dampers 113, 114, 115 are moved closer to the reference opening position (the rear ends of the characteristic lines of the gas distribution dampers 113, 114, 115 are closer to the dotted lines), and instead the return dampers 122, 123 and 124 are shifted from the reference opening positions (the rear ends of the characteristic lines of the return dampers 122, 123, and 124 are separated from the dotted lines).

  As described above, the return dampers 122, 123, and 124 themselves deviate from the reference opening position (indicated by a dotted line) where the optimum operability is obtained, but the return dampers 122, 123, and 124 themselves are the gas distribution damper 113, It is not necessary to operate according to the steam temperature as in 114 and 115, and this is not a problem immediately.

  However, when time elapses, the return dampers 122, 123, and 124 may be displaced from their original positions and stabilized. Although the highest priority is to maintain the second pass gas distribution damper 113 and the third pass gas distribution damper 114 at the reference opening position, the return dampers 122, 123, and 124 are also greatly deviated from the reference opening position. Then, since the second pass and third pass gas distribution dampers 113 and 114 cannot be returned to the reference opening position, the return dampers 122, 123, and 124 should be returned to the reference opening position if possible.

  First, since the first pass gas distribution damper 115 can absorb the fluctuation of the steam temperature by the flow rate of the fuel 107 and the flow rate of the feed water 106, the first pass gas distribution damper 114 can be arbitrarily operated.

  On the other hand, with respect to the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123, if both dampers are closed from the reference opening position, the gas flow rate is gradually opened while maintaining a balance. To operate. If both dampers are open from the standard opening position, operate in the direction to close gradually while maintaining the balance of gas flow.

  One of the dampers is opened, and the other damper is closed. This point needs to be adjusted in consideration of the characteristics of the boiler device and the damper. The first stage reheat steam temperature 110 and the second stage reheat steam temperature 111 have the same importance, and the sensitivity of each steam temperature to the second pass gas distribution damper 113 and the third pass gas distribution damper 114 is about the same. Assuming that the opening degree of the second pass gas distribution damper 113 and the opening degree of the third pass gas distribution damper 114 are different from the reference opening position as shown in FIG. 10 or FIG. It is good to adjust so that it becomes the same size.

  FIGS. 10 and 11 are diagrams showing another case in which the opening degree of the gas distribution dampers 113 and 114 is adjusted to the reference opening degree position using the return dampers 122 and 123. FIG. 10 and 11, the opening positions of the return damper 122 and the return damper 123 are different.

  When the reheat steam temperature fluctuates beyond a predetermined value, the return dampers 122, 123, and 124 are used for reheat steam temperature control. When divided into the dampers 122, 123, and 124, the effects of the gas distribution dampers 113, 114, and 115 are reduced. That is, even if the gas distribution dampers 113, 114, 115 are operated at the same opening degree, the combustion gas flow rate is greater when the return dampers 122, 123, 124 are present than when the return dampers 122, 123, 124 are not present. The change of becomes smaller.

  If there are fluctuations in the normal first stage reheat steam temperature 110 and second stage reheat steam temperature 111, a sudden reheat steam temperature such as when a soot blower is blown around the reheater can be used without any problem. In such a case, it is conceivable that only the operation of the gas distribution dampers 113, 114, 115 is not in time. In that case, if the fluctuation of the reheat steam temperature is monitored and the gas distribution dampers 113, 114, 115 cannot cope with it, the return dampers 122, 123, 124 are reheated from the adjustment of the gas distribution dampers 113, 114, 115. Switch to a mode that controls the steam temperature.

FIG. 12 is an enlarged schematic configuration diagram of a main part for explaining a boiler steam temperature control device according to a second embodiment of the present invention.
In this two-stage reheating boiler apparatus, the rear heat transfer section is divided into three passes, a first pass 68, a second pass 69, and a third pass 70, and the first pass 68 is upstream in the combustion gas flow direction. Is provided with a primary superheater (1SH) 102, and a first stage primary reheater (1RH (1)) 103 is installed upstream of the second path 69 in the flow direction of the combustion gas. A second-stage primary reheater (1RH (2)) 104 is installed upstream of the path 70 in the combustion gas flow direction. A economizer (ECO) 52 is installed downstream of the primary superheater 102 and the reheaters 103 and 104 in the direction of combustion gas flow.

  A first pass gas distribution damper 115 is disposed upstream of the economizer (ECO) 52 in the first path 68 in the combustion gas flow direction, and a first pass gas distribution damper return damper 124 is disposed downstream thereof. Has been placed. The damper opening degree of the first pass gas distribution damper 115 is measured by a damper opening degree sensor 118, and the damper opening degree of the first pass gas distribution damper return damper 124 is measured by a damper opening degree sensor 127.

  A second pass gas distribution damper 113 is disposed upstream of the economizer (ECO) 52 in the second path 69 in the combustion gas flow direction, and a second pass gas distribution damper return damper 122 is disposed downstream thereof. Has been placed. The damper opening degree of the second pass gas distribution damper 113 is measured by a damper opening degree sensor 116, and the damper opening degree of the second pass gas distribution damper return damper 122 is measured by a damper opening degree sensor 125.

  A third pass gas distribution damper 114 is disposed upstream of the economizer (ECO) 52 of the third path 70 in the combustion gas flow direction, and a third pass gas distribution damper return damper 123 is disposed downstream thereof. Has been placed. The damper opening degree of the third pass gas distribution damper 114 is measured by a damper opening degree sensor 117, and the damper opening degree of the third pass gas distribution damper return damper 123 is measured by a damper opening degree sensor 126.

In the present embodiment, the main difference from the first embodiment is that the gas distribution dampers 113, 114, 115 and the return dampers 122, 123, 124 are arranged in parallel in the first embodiment. On the other hand, in this embodiment, the gas distribution dampers 113, 114, 115 and the return dampers 122, 123, 124 are arranged in series, respectively.
Note that the control of the reheat steam temperature and the like is the same as that in the first embodiment, and a duplicate description is omitted.

  In the present embodiment, the return dampers 122, 123, 124 are provided on the downstream side in the combustion gas flow direction of the gas distribution dampers 113, 114, 115, but on the upstream side in the combustion gas flow direction of the gas distribution dampers 113, 114, 115. It is also possible to provide it.

  In the embodiment, for convenience of explanation, the reheat steam temperature control unit 112, the return damper control units 119, 120, and 121 and the return damper calculation unit 128 are individually displayed and described. It is also possible to double the function.

  In the above embodiment, the inside of the flue of the rear heat transfer unit is divided into three passes, but if necessary, the inside of the flue of the rear heat transfer unit is divided into three or more, for example, four, and the superheater is divided into the first pass. And a first pass gas distribution damper, a second pass with a first stage reheater and a second pass gas distribution damper, a third pass with a second stage reheater and a third pass gas distribution damper, and a fourth pass It is also possible to provide a third stage reheater and a fourth pass gas distribution damper.

  As described above, according to the present invention, the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are provided to adjust the opening degree of the second pass gas distribution damper 113 and the third pass gas distribution damper 114. And when the opening degree of the second pass gas distribution damper 113 or the third pass gas distribution damper 114 deviates from a preset reference opening range, the opening degree of the gas distribution damper falls within the reference opening range. The gas distribution damper return damper corresponding to the gas distribution damper is operated so as to return the gas distribution damper.

  Thus, the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 operate so that the second pass gas distribution damper 113 and the third pass gas distribution damper 114 are within the reference opening range. As a result, the second pass gas distribution damper 113 and the third pass gas distribution damper 114 can maintain the optimum opening when stable. Further, the second pass gas distribution damper return damper 122 and the third pass gas distribution damper return damper 123 are configured such that when the second pass gas distribution damper 113 and the third pass gas distribution damper 114 are out of the reference opening range, the reference opening range. Since the second pass gas distribution damper 113 and the third pass gas distribution damper 114 need only control the reheat steam temperature, the functions are shared and the control logic is simplified. Have.

    67 ... Flue, 68 ... First pass, 69 ... Second pass, 70 ... Third pass, 101 ... Boiler device, 102 ... Horizontally placed primary superheater, 103 ... First stage horizontal reheater, 104 ... Second stage horizontal reheater, 105 ... Main steam temperature, 106 ... Main steam temperature controller, 107 ... Fuel, 108 Water supply, 109a, 109b ... spray, 110 ... first stage reheat steam temperature, 111 ... second stage reheat steam temperature, 112 ... reheat steam temperature control unit, 113 ... Second pass gas distribution damper, 114 ... third pass gas distribution damper, 115 ... first pass gas distribution damper, 116 ... damper opening sensor, 117 ... damper opening sensor, 118 ... damper Opening sensor, 119 ... return damper control unit, 120 ... return damper control 121, return damper control unit, 122, second pass gas distribution damper return damper, 123, third pass gas distribution damper return damper, 124, first pass gas distribution damper return damper 125 ... damper opening sensor, 126 ... damper opening sensor, 127 ... damper opening sensor, 128 ... return damper calculation unit, G ... combustion gas.

Claims (3)

Dividing the flue of the rear heat transfer section into a first pass, a second pass, and a third pass extending in the direction of combustion gas flow by the partition wall,
A superheater is disposed upstream of the first pass in the combustion gas flow direction, and a first pass gas distribution damper is disposed downstream of the combustion gas flow direction;
A first stage reheater is disposed upstream of the second pass in the combustion gas flow direction, a second pass gas distribution damper is disposed downstream of the combustion gas flow direction, and the second pass gas distribution damper is operated to operate the second pass gas distribution damper. The first stage reheat steam temperature is controlled by adjusting the flow rate of the combustion gas flowing through the second path,
A second stage reheater is disposed upstream of the third pass in the combustion gas flow direction, a third pass gas distribution damper is disposed downstream of the combustion gas flow direction, and the third pass gas distribution damper is operated to In the reheat steam temperature control device that controls the second stage reheat steam temperature by adjusting the flow rate of the combustion gas flowing in the third pass,
A first pass gas for returning the opening degree of the first pass gas distribution damper to the reference opening range when the opening degree of the first pass gas distribution damper deviates from a predetermined reference opening range of the damper. A distribution damper return damper is provided in the first path,
A second pass gas for returning the opening degree of the second pass gas distribution damper to the reference opening range when the opening degree of the second pass gas distribution damper deviates from a predetermined reference opening range of the damper. Distribution damper return damper is provided in the second path,
Third pass gas distribution damper return for returning the opening degree of the third pass gas distribution damper to the reference opening range when the opening degree of the third pass gas distribution damper is out of a predetermined reference opening range. A reheat steam temperature control device characterized in that a damper is provided in the third path. In the reheat steam temperature control device according to claim 1,
A reheat steam temperature control device, wherein each of the gas distribution dampers and the return damper are provided in parallel with the combustion gas flow direction. In the reheat steam temperature control device according to claim 1,
The reheat steam temperature control device characterized in that each return damper is provided on the downstream side or the upstream side in the combustion gas flow direction with respect to each gas distribution damper.

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