JP2022112859A - Operational state improvement system, power generation plant, operational state improvement method and operational state improvement program - Google Patents

Abstract

To provide an operational state improvement system, a power generation plant, an operational state improvement method and an operational state improvement program, which can effectively improve an operational state of a boiler.SOLUTION: An operational state improvement system 200 includes an adjustment section in which settable ranges of predetermined operation parameters (mill outlet temperature, conveyance gas flow rate, boiler outlet oxygen concentration and auxiliary gas flow rate) are preset and that adjusts the operation parameters within the settable ranges on the basis of a predetermined evaluation index based on an operational state of a boiler 10.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to an operating state improvement system, a power plant, an operating state improving method, and an operating state improving program.

2. Description of the Related Art A large-sized boiler such as a boiler for power generation has a hollow, vertically installed furnace, and a plurality of burners are arranged along the circumferential direction of the furnace wall. A large-sized boiler has a flue connected vertically above the furnace, and a heat exchanger for generating steam is arranged in the flue. Then, the burner injects a mixture of fuel and air (oxidizing gas) into the furnace to form a flame and generate combustion gas that flows into the flue. A heat exchanger is installed in a region where the combustion gas flows, and superheated steam is generated by heating water or steam flowing inside the heat transfer tubes constituting the heat exchanger.

In order to optimize boiler operation, Patent Literature 1 discloses a method using AI.

JP 2018-128995 A

Normally, the operating parameters in boiler control are adjusted using a standard fuel (design fuel) type in trial operation, and the values of the operating parameters are set based on the adjustment results. Therefore, it is desired to more effectively optimize the boiler operating parameters in accordance with the operating conditions that change depending on the properties of the fuel used and the cumulative operating time.

When AI is used as in Patent Document 1, a model is required to predict and reproduce the operating state of the boiler when the input conditions (fuel used, operating parameters, etc.) are changed. However, there are issues such as cost and cost.

The present disclosure has been made in view of such circumstances, and an operating state improvement system and power plant that can effectively improve the operating state of a boiler, an operating state improving method, and an operating state improving program intended to provide

In a first aspect of the present disclosure, a settable range is set in advance for a predetermined operating parameter, and the operating parameter is adjusted within the settable range based on a predetermined evaluation index based on the operating state of the boiler. It is a driving condition improvement system provided with an adjustment unit that

In a second aspect of the present disclosure, a settable range is set in advance for a predetermined operating parameter, and the operating parameter is adjusted within the settable range based on a predetermined evaluation index based on the operating state of the boiler. It is an operating state improvement method having a step of

A third aspect of the present disclosure is that a settable range is set in advance for a predetermined operating parameter, and the operating parameter is adjusted within the settable range based on a predetermined evaluation index based on the operating state of the boiler. It is an operating condition improvement program for causing a computer to execute the process to

According to the present disclosure, it is possible to effectively improve the operating state of the boiler.

1 is a schematic configuration diagram representing a coal-fired boiler according to a first embodiment of the present disclosure; FIG. 1 is a schematic diagram showing steam, condensate, and water supply systems in a coal-fired boiler (once-through boiler) according to the first embodiment of the present disclosure; FIG. It is a figure showing a concrete example of composition of a boiler system concerning a 1st embodiment of this indication. It is a figure showing an example of hardware constitutions of a control device concerning a 1st embodiment of this indication. FIG. 2 is a functional block diagram showing functions provided by a control device according to the first embodiment of the present disclosure; FIG. FIG. 4 is a diagram showing an example of the relationship between mill outlet temperature and boiler efficiency according to the first embodiment of the present disclosure; FIG. 4 is a diagram showing an example of the relationship between the carrier gas flow rate and the boiler efficiency according to the first embodiment of the present disclosure; FIG. 4 is a diagram showing an example of the relationship between boiler outlet oxygen concentration and boiler efficiency according to the first embodiment of the present disclosure; FIG. 4 is a diagram showing an example of the relationship between auxiliary gas flow rate and boiler efficiency according to the first embodiment of the present disclosure; 4 is a flow chart showing an example of a procedure of operation parameter adjustment processing according to the first embodiment of the present disclosure; FIG. 4 is a diagram showing the order of priority of operating parameter adjustment processing according to the first embodiment of the present disclosure; FIG. 11 is a flow chart showing an example of a procedure of operation parameter adjustment processing according to the second embodiment of the present disclosure; FIG.

[First Embodiment]
A first embodiment of an operating state improving system, a power plant, an operating state improving method, and an operating state improving program according to the present disclosure will be described below with reference to the drawings. It should be noted that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, the present invention includes a combination of each embodiment. In the following description, "up" and "up" indicate the upper side in the vertical direction, and "down" and "lower side" indicate the lower side in the vertical direction.

FIG. 1 is a schematic diagram showing the coal-fired boiler of this embodiment.

The coal-fired boiler 10 of the present embodiment uses pulverized coal obtained by pulverizing coal (carbon-containing solid fuel) as a pulverized fuel, burns the pulverized fuel with a burner, and heats the heat generated by this combustion with water supply and steam. It is a coal-fired (pulverized coal-fired) boiler capable of generating superheated steam by

In this embodiment, a coal-fired boiler 10 has a furnace 11, a combustion device 12, and a combustion gas passage 13, as shown in FIG. The furnace 11 has a hollow rectangular shape and is installed along the vertical direction. The furnace wall 101 constituting the furnace 11 is composed of a plurality of heat transfer tubes and fins connecting them, and heat generated by combustion of the pulverized fuel is heat-exchanged with water and steam flowing inside the heat transfer tubes, It suppresses the temperature rise of the furnace wall.

The combustion device 12 is provided on the lower side of the furnace wall that constitutes the furnace 11 . In this embodiment, the combustion device 12 has a plurality of burners (eg 21, 22, 23, 24, 25) mounted on the furnace wall. For example, the burners 21, 22, 23, 24, and 25 are arranged at equal intervals along the circumferential direction of the furnace 11 as one set, and a plurality of stages (for example, five stages in FIG. 1) are arranged along the vertical direction. are placed. However, the shape of the furnace, the number of burners in one stage, the number of stages, the arrangement, etc. are not limited to this embodiment.

The burners 21 , 22 , 23 , 24 , 25 are connected to a plurality of mills (crusher) 31 , 32 , 33 , 34 , 35 via pulverized coal supply pipes 26 , 27 , 28 , 29 , 30 . The mills 31, 32, 33, 34, and 35 have, for example, a grinding table (not shown) rotatably supported in a housing of the mill, and above the grinding table a plurality of grinding rollers (not shown) for grinding. It is configured to be supported so as to be rotatable in conjunction with the rotation of the table. When the coal is thrown between a plurality of crushing rollers and the crushing table, it is crushed, and the primary air fan (PAF: Primary
The pulverized fuel that is transported to the classifier (not shown) in the mill housing by the carrier gas (primary air, oxidizing gas) supplied from the air fan 38B and classified within a predetermined particle size range, The burners 21 , 22 , 23 , 24 , 25 can be supplied from pulverized coal supply pipes 26 , 27 , 28 , 29 , 30 .

Further, the furnace 11 is provided with a wind box 36 at the mounting positions of the burners 21, 22, 23, 24, and 25, and one end of an air duct (airway) 37 is connected to the wind box 36. As shown in FIG. The air duct 37 is provided with a forced draft fan (FDF) 38A at the other end.

The combustion gas passage 13 is connected to the upper portion of the furnace 11 in the vertical direction, as shown in FIG. The combustion gas passage 13 is provided with superheaters 102, 103, 104, reheaters 105, 106, and an economizer 107 as heat exchangers for recovering the heat of the combustion gas. Heat is exchanged between the combustion gas and feed water or steam flowing through each heat exchanger.

As shown in FIG. 1, the combustion gas passage 13 is connected to the downstream side thereof with a flue 14 through which the combustion gas that has undergone heat exchange is discharged. An air heater (air preheater) 42 is provided between the flue 14 and the air duct 37, and heat exchange is performed between the air flowing through the air duct 37 and the combustion gas flowing through the flue 14. The combustion air supplied to 22, 23, 24, 25 can be heated.

Further, the flue 14 is provided with a denitrification device 43 at a position upstream of the air heater 42 . The denitrification device 43 supplies a reducing agent such as ammonia or urea water, which has a function of reducing nitrogen oxides, into the flue 14, and causes a reaction between the nitrogen oxides in the combustion gas to which the reducing agent is supplied and the reducing agent. is accelerated by the catalytic action of the denitration catalyst installed in the denitration device 43, thereby removing and reducing nitrogen oxides in the combustion gas.
The gas duct 41 connected to the flue 14 is provided with a dust collector 44 such as an electric dust collector, an induced draft fan (IDF) 45, a desulfurization device 46, etc., at a position downstream of the air heater 42. A chimney 50 is provided at the end.

On the other hand, when the plurality of mills 31, 32, 33, 34, 35 are driven, the produced pulverized fuel is fed through the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the carrier gas (primary air, oxidizing gas). The burners 21, 22, 23, 24, 25 are supplied. In addition, by exchanging heat with the exhaust gas discharged from the flue 14 by the air heater 42, the heated combustion air (secondary air, oxidizing gas) is supplied from the air duct 37 through the wind box 36 to the burner 21, 22, 23, 24, 25. The burners 21, 22, 23, 24, and 25 blow into the furnace 11 a pulverized fuel mixture in which pulverized fuel and carrier gas are mixed, and also blow combustion air into the furnace 11. At this time, the pulverized fuel mixture is ignited. By doing so, a flame can be formed. A flame is generated in the lower part of the furnace 11 , and high-temperature combustion gas rises inside the furnace 11 and is discharged to the combustion gas passage 13 . Air is used as the oxidizing gas in this embodiment. It may have a higher or lower oxygen ratio than air, and can be used by optimizing the fuel flow rate.

Further, the furnace 11 is provided with an additional air port 39 above the mounting positions of the burners 21, 22, 23, 24 and 25. As shown in FIG. An end of an additional air duct 40 branched from the air duct 37 is connected to the additional air port 39 . Therefore, the combustion air (secondary air, oxidizing gas) sent by the forced draft fan 38A is supplied from the air duct 37 to the wind box 36, from which the burners 21, 22, 23, 24, 25 are supplied. , and additional air for combustion (additional air) delivered by forced draft fan 38A can be supplied from additional air duct 40 to additional air port 39. As shown in FIG.

In the lower region CA1 of the furnace 11, the pulverized fuel mixture and combustion air (secondary air, oxidizing gas) are combusted to generate flame. The inside of the furnace 11 is maintained in a reducing atmosphere by setting the amount of air supplied to be less than the theoretical amount of air with respect to the amount of pulverized coal supplied. That is, nitrogen oxides (NOx) generated by combustion of pulverized coal are reduced in the region CA2 of the furnace 11, and then additional air for combustion (additional air) is additionally supplied from the additional air port 39, thereby reducing pulverized coal. Oxidative combustion is completed, and the amount of NOx generated by the combustion of pulverized coal is reduced.

After that, as shown in FIG. 1, the combustion gas is transferred to the second superheater 103, the third superheater 104, and the first superheater 102 (hereinafter sometimes simply referred to as superheaters) arranged in the combustion gas passage 13. ), the second reheater 106, the first reheater 105 (hereinafter sometimes simply referred to as a reheater), and the economizer 107. After that, nitrogen oxides are reduced and removed by the denitrification device 43. After the particulate matter is removed by the dust collector 44 and the sulfur oxides are removed by the desulfurization device 46, the dust is discharged from the stack 50 into the atmosphere. Note that the heat exchangers do not necessarily have to be arranged in the order described above with respect to the combustion gas flow.

Next, the superheaters 102, 103, 104, the reheaters 105, 106, and the economizer 107 provided in the combustion gas passage 13 as heat exchangers will be described in detail. FIG. 2 is a schematic diagram showing a heat exchanger provided in the coal-fired boiler 10. As shown in FIG.
Note that FIG. 1 does not accurately show the positions of the heat exchangers (superheaters 102, 103, 104, reheaters 105, 106, economizer 107) in the combustion gas passage 13. The arrangement order of the exchangers relative to the combustion gas flow is not limited to that shown in FIG.

As shown in FIG. 2, the boiler power plant 1 of the present embodiment includes heat exchangers (superheaters 102, 103, 104, reheaters 105, 106, economizer 107) provided in the coal-fired boiler 10. , a steam turbine 110 that is rotationally driven by the steam generated by the coal-fired boiler 10, and a generator 115 that is connected to the steam turbine 110 and generates power by the rotation of the steam turbine 110.

A steam turbine 110 that is rotationally driven by the steam generated by the coal-fired boiler 10 includes, for example, a high-pressure turbine 111, an intermediate-pressure turbine 112, and a low-pressure turbine 113. Steam from reheaters 105 and 106, which will be described later, After entering the pressure turbine 112 , it enters the low pressure turbine 113 . A condenser 114 is connected to the low-pressure turbine 113, and the steam that rotationally drives the low-pressure turbine 113 is cooled by cooling water (eg, seawater) in the condenser 114 to become condensed water. Condenser 114 is connected to economizer 107 via water supply line L1. The water supply line L1 is provided with, for example, a condensate pump (CP) 121, a low pressure water supply heater 122, a boiler water supply pump (BFP) 123, and a high pressure water supply heater . Part of the steam that drives the steam turbines 111, 112, and 113 is extracted to the low-pressure feedwater heater 122 and the high-pressure feedwater heater 124, and the high-pressure feedwater heater 124 and the low-pressure feedwater heater 122 are supplied via extraction lines (not shown). as a heat source to heat the feed water supplied to the economizer 107 .

For example, a case where the coal-fired boiler 10 is a once-through boiler will be described. An economizer 107 is connected to each evaporator tube of the furnace wall 101 . The feed water heated by the economizer 107 is heated by radiation from the flame in the furnace 11 when passing through the evaporating pipes forming the furnace wall 101 and is led to the steam separator 126 . The steam separated by the steam separator 126 is supplied to the superheaters 102, 103, and 104, and the drain water separated by the steam separator 126 is sent through the steam separator drain tank 127 to the drain water line L2. to the condenser 114.

In addition, when the once-through boiler is started or during low-load operation, the feed water supplied from the economizer 107 does not evaporate completely when passing through the evaporation pipes constituting the furnace wall 101, and as a result, the steam is separated. An operating state (wet operating state) in which a water level exists in the vessel 126 may occur. In this wet operation state, the drain water separated by the steam separator 126 is joined to the middle of the water supply line L1 through the circulation line L6 using the boiler circulation pump (BCP) 128, so that the economizer 107 may be circulated and supplied to the evaporation tubes forming the furnace wall 101.

When the combustion gas flows through the combustion gas passage 13 , the combustion gas is heat-recovered by the superheaters 102 , 103 , 104 , the reheaters 105 , 106 and the economizer 107 . On the other hand, the feed water supplied from the boiler feed water pump (BFP) 123 is preheated by the economizer 107 and then heated to steam when passing through the evaporating pipes forming the furnace wall 101. be guided. The steam separated by the steam separator 126 is introduced into the superheaters 102, 103, 104 and superheated by the combustion gas. The superheated steam generated by the superheaters 102, 103, 104 is supplied to the high pressure turbine 111 via the steam line L3, and drives the high pressure turbine 111 to rotate. Steam discharged from the high-pressure turbine 111 is introduced to the reheaters 105 and 106 via the line L4 to be heated again. The re-superheated steam is supplied to the low-pressure turbine 113 through the intermediate-pressure turbine 112 via the steam line L5, and drives the intermediate-pressure turbine 112 and the low-pressure turbine 113 to rotate. The rotating shaft of each steam turbine 111, 112, 113 rotates a generator 115 to generate power. The steam discharged from the low-pressure turbine 113 is cooled by the condenser 114 to become condensed water, and is sent to the economizer 107 again through the water supply line L1.

Further, in the combustion gas passage 13, a suit (not shown) is provided between the heat transfer tubes of each heat exchanger such as the superheaters 102, 103, 104, the reheaters 105, 106, and the economizer 107, or between the heat exchangers. A blower (ash removal device) may be arranged. The soot blower is arranged to extend in a direction substantially perpendicular to the wall surface of the combustion gas passage 13 . The soot blower is an injection device that takes the vertical direction to the wall surface of the combustion gas passage 13 as an axial direction, injects steam (gas) in a direction perpendicular to the axial direction, and can also change the injection direction. The steam injected from the soot blower toward heat exchangers such as superheaters 102, 103, 104, reheaters 105, 106, economizer 107 adheres and accumulates on the surface of each heat transfer tube of the heat exchanger. Removes ash and suppresses deterioration of heat exchange efficiency in each heat transfer tube of the heat exchanger.

Next, a specific configuration example of the configuration (boiler system) around the coal-fired boiler 10 will be described with reference to FIG.
As shown in FIG. 3, the primary air is pressurized by the primary air ventilator 38B and branched into a cold air flow path and a hot air flow path via the PAF damper D1. In the hot air flow path, part of the primary air is heated as hot air via the air heater 42, joins with cold air via the hot air dampers W1, W2, W3, W4, W5, and flows through the mills 31, 32, 33, 34, 35.

In the cold air flow path, a portion of the primary air bypasses the air heater 42 as cold air, joins with the hot air via the cold air dampers R1, R2, R3, R4, R5, and passes through the mills 31, 32, 32, 32 as primary air. 33, 34 and 35. The primary air supplied to the mills 31, 32, 33, 34, 35 is supplied to the burners 21, 22, 23, 24, 25 through the pulverized coal supply pipes 26, 27, 28, 29, 30 together with pulverized fuel as carrier gas. supplied.

The temperature of the mixed fluid of pulverized fuel and primary air discharged from each mill is measured at T1 in FIG. That is, the temperature at T1 is the mill outlet temperature, which is the temperature of the mixed fluid of pulverized fuel and primary air discharged from the mill. Note that the mill exit temperature is measured for each mill individually.

As shown in FIG. 3, secondary air is pressurized by a forced draft fan 38A, adjusted in flow rate by a damper (FDF damper) D2, and heated by an air heater . Heated secondary air is supplied to windbox 36 and from burners 21 , 22 , 23 , 24 , 25 into furnace 11 of boiler 10 .

The differential pressure between the inlet of the secondary air to the wind box 36 and the pressure inside the furnace 11 is defined as the wind box differential pressure, which is measured at P1 in FIG. The wind box 36 is provided with dampers (not shown) for adjusting the flow rate of the secondary air supplied to the burners 21 , 22 , 23 , 24 and 25 .

Exhaust gas, which is combustion gas discharged from the boiler 10 , exchanges heat with secondary air in the air heater 42 . The oxygen concentration of the exhaust gas discharged from the boiler 10 is measured at M1 in FIG. That is, the oxygen concentration at M1 becomes the boiler outlet oxygen concentration, which is the oxygen concentration of the combustion gas (exhaust gas) discharged from the boiler 10 . After heat exchange by the air heater 42, that is, the temperature of the exhaust gas after heat recovery by the boiler system (air heater exit gas temperature) is measured at T2.

Further, the carrier gas flow rate, which is the flow rate of the primary air supplied to each of the mills 31, 32, 33, 34 and 35, is measured at F3 in FIG.

As shown in FIG. 3, in a configuration in which a plurality of mills 31, 32, 33, 34, and 35 are provided, when the power plant 1 is operated at a partial load (a load smaller than the rated load), some of the mills (for example, 32 , 33, 34, 35) are activated (corresponding burners 22, 23, 24, 25 are ignited), and other mills (for example, mill 31) are deactivated (corresponding burners 21 are extinguished). This stopped mill (e.g. mill 31) is supplied with cold air as an auxiliary gas (auxiliary primary air). Hot air is not supplied to the stopped mill. Thus, the auxiliary gas flow rate, which is the flow rate of the auxiliary primary air supplied to the stopped mill, is also measured at F3 in FIG.

Next, the control device 200 will be explained.
The control device 200 controls the power plant 1 . In particular, the control device 200 according to the present embodiment performs improvement control of the operating state of the boiler 10 .

FIG. 4 is a diagram showing an example of the hardware configuration of the control device 200 according to this embodiment.
As shown in FIG. 4, the control device 200 is a computer system (computer system). A RAM (Random Access Memory) 1300 functioning as a work area, a hard disk drive (HDD) 1400 as a large-capacity storage device, and a communication unit 1500 for connecting to a network or the like. A solid state drive (SSD) may be used as the mass storage device. These units are connected via a bus 1800 .

Further, the control device 200 may include an input section such as a keyboard and a mouse, and a display section such as a liquid crystal display device for displaying data.

Note that the storage medium for storing programs and the like executed by the CPU 1100 is not limited to the ROM 1200 . For example, other auxiliary storage devices such as magnetic disks, magneto-optical disks, and semiconductor memories may be used.

A series of processes for realizing various functions to be described later is recorded in the hard disk drive 1400 or the like in the form of a program. As a result, various functions to be described later are realized. The program is pre-installed in the ROM 1200 or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

FIG. 5 is a functional block diagram showing functions provided in the control device (operating state improvement system) 200. As shown in FIG. As shown in FIG. 5 , the control device 200 includes an adjustment confirmation section 201 , an evaluation section 202 and an adjustment section 203 . Note that the adjustment confirmation unit 201 and the evaluation unit 202 may be omitted.

The adjustment confirmation unit 201 determines whether or not the operating parameters are adjustable. Specifically, as described later, a settable range is set for the operating parameter, so the difference between the current value of the operating parameter and the limit value of the settable range is checked. For example, if the target operating parameter is the mill outlet temperature, the current mill outlet temperature is compared with the upper limit value in the settable range to calculate the difference. Then, it is determined whether or not this difference is equal to or greater than a preset threshold.

The threshold value is set as the maximum value of the difference that is assumed that the current operating parameter value is sufficiently close to the limit value of the settable range and that the effect of improving the boiler efficiency cannot be expected even if it is adjusted to the limit value. That is, the threshold is set so that it can be determined that the value of the driving parameter is close to the limit value. A threshold value is preferably set for each operating parameter.

For example, before adjustment is performed by the adjustment unit 203, which will be described later, the operation parameter to be adjusted is checked by the adjustment confirmation unit 201, and if the difference is equal to or greater than a preset threshold value, adjustment processing is actually performed. On the other hand, if the difference is less than the preset threshold value, the adjustment processing for this operating parameter is not executed. That is, the adjusting unit 203, which will be described later, does not adjust the operating parameter for which the difference (adjustable amount) of the operating parameter in the settable range is smaller than the threshold.

In this manner, the adjustment confirmation unit 201 can confirm whether or not the operation parameter needs to be adjusted, thereby suppressing execution of unnecessary adjustment processing. It should be noted that the adjustment processing may be performed by the adjustment unit 203, which will be described later, without executing the confirmation processing by the adjustment confirmation unit 201. FIG.

The evaluation unit 202 calculates a predetermined evaluation index (evaluation index) calculated from the operating state value of the boiler 10 . In this embodiment, the evaluation index is the amount of improvement in boiler efficiency. That is, the evaluation unit 202 uses the operating state value of the boiler 10 to evaluate the improvement amount of the boiler efficiency. Note that the evaluation index is not limited to the amount of improvement in boiler efficiency, and can be set as long as it changes with changes in operating conditions (adjustment of operating parameters).

In the evaluation unit 202, the improvement amount of the boiler efficiency is calculated based on the change in the predetermined operating state value before and after the adjustment of the operating parameter. Evaluate whether there is improvement. Note that the operating state value used for the evaluation is set in advance as a parameter capable of calculating the improvement amount of the boiler efficiency.

In this embodiment, the operating state values are the boiler outlet oxygen concentration M1 and the air heater outlet gas temperature T2. The boiler outlet oxygen concentration M1 is the oxygen concentration of the combustion gas discharged from the boiler 10 . The air heater outlet gas temperature T2 is the temperature of the combustion gas discharged from the air heater 42 that exchanges heat between the combustion gas discharged from the boiler 10 and the air supplied to the boiler 10, and is used for heat recovery in the boiler system. It indicates the temperature of the finished combustion gases.

Specifically, the evaluation unit 202 calculates the boiler efficiency improvement amount due to the change in the air heater outlet gas temperature T2 and the boiler efficiency improvement amount due to the change in the boiler outlet oxygen concentration M1.

The boiler efficiency improvement amount due to the change in the air heater outlet gas temperature T2 is calculated by a function ηt2 (ΔT2) for the change amount ΔT2 in the air heater outlet gas temperature T2. The amount of change ΔT2 in the air heater outlet gas temperature is obtained by subtracting T2b, which is the air heater outlet gas temperature before adjustment, from T2a, which is the air heater outlet gas temperature after adjustment (ΔT2=T2a−T2b). The function ηt2 is a function defined in advance for calculating the boiler efficiency improvement amount from the change amount ΔT2 of the air heater outlet gas temperature T2, and may be a theoretical formula (design formula), and is obtained from past operation results. It may be an empirical formula.

The boiler efficiency improvement amount due to the change in the boiler outlet oxygen concentration M1 is calculated by a function ηm1(ΔC) with respect to the amount of change ΔC in the boiler outlet oxygen concentration M1. The amount of change ΔC in the boiler outlet oxygen concentration M1 is obtained by subtracting C1b, which is the boiler outlet oxygen concentration M1 before adjustment, from C2a, which is the boiler outlet oxygen concentration M1 after adjustment (ΔC=C2a−C1b). The function ηm1 is a function defined in advance for calculating the boiler efficiency improvement amount from the amount of change ΔC in the boiler outlet oxygen concentration M1, and may be a theoretical formula (design formula), and is obtained from past operating results. It may be an empirical formula.

Then, the evaluation unit 202 adds the boiler efficiency improvement amount ηt2 (ΔT) due to the change in the air heater outlet gas temperature T2 and the boiler efficiency improvement amount ηm1 (ΔC) due to the change in the boiler outlet oxygen concentration M1 to obtain the total boiler Calculate the amount of efficiency improvement. That is, the total boiler efficiency improvement amount is calculated as ηt2(ΔT)+ηm1(ΔC).

The evaluation process in the evaluation unit 202 is performed, for example, to confirm the improvement result after the operation parameter is adjusted in the adjustment unit 203, which will be described later. Also, the evaluation processing in the evaluation unit 202 may be performed before the adjustment processing in the adjustment unit 203 is executed. In this case, for example, the estimated value of the boiler efficiency improvement amount is calculated based on the adjustable amount of the operating parameter. For example, as described above, when ηt2 (ΔT) + ηm1 (ΔC) is used to calculate the total boiler efficiency improvement amount, ΔT2 and ΔC are estimated from the current value and adjustable amount of each operating parameter, and then Estimated boiler efficiency improvement amount is calculated based on Then, when the estimated boiler efficiency improvement amount is equal to or greater than a preset threshold value, the operation parameter may be adjusted.

The adjustment unit 203 has a settable range set in advance for a predetermined operating parameter related to the evaluation index, and adjusts the operating parameter within the settable range based on the evaluation index.

The operating parameters are preset based on the degree of influence on the evaluation index. The degree of influence represents the magnitude of change in the evaluation index with respect to the adjustment of the operating parameters. That is, it is possible to effectively adjust the evaluation index by adjusting the operating parameter having a high degree of influence.

In this embodiment, the operating parameter is at least one of mill outlet temperature, carrier gas flow rate, boiler outlet oxygen concentration, and auxiliary gas flow rate. Note that any operating parameter that has a large impact on the evaluation index can be used without being limited to the above. The mill outlet temperature is the temperature of the pulverized fuel and carrier gas mixture exiting the mill. The carrier gas flow rate is the flow rate of the carrier gas supplied to the mill. The boiler outlet oxygen concentration is the oxygen concentration of the combustion gas discharged from the boiler 10 . The auxiliary gas flow rate is the flow rate of the auxiliary gas supplied to the stopped mill when a plurality of mills are provided for the boiler 10 .

Then, when using a plurality of operating parameters, the adjusting unit 203 adjusts the operating parameters in descending order of influence on the evaluation index. The degree of influence on the evaluation index indicates the degree to which the evaluation index can be effectively improved when the operating parameters are adjusted.

In this embodiment, the order of adjustment of the operating parameters is set in advance in consideration of the degree of influence. Specifically, the adjustment unit 203 adjusts each operating parameter in the order of the boiler outlet oxygen concentration M1, the mill outlet temperature T1, the carrier gas flow rate F3h, and the auxiliary gas flow rate F3c. Note that the order may be changed from the above, or if there are operational parameters that are not used, the unused operational parameters may be omitted from the above order.

The adjustment of each operating parameter will be explained. Devices (such as dampers) to be operated in the adjustment of each operating parameter below are not limited to the described means, and other means may be used as long as the purpose of adjustment can be achieved.

First, the case of adjusting the mill outlet temperature will be described.
Adjuster 203 increases mill outlet temperature T1 to improve boiler efficiency. Specifically, the mill outlet temperature is increased by manipulating the set value of the mill outlet temperature T1 up to the upper limit of the settable range.

The upper limit of the settable range of the mill outlet temperature T1 is set based on the properties of coal to be used. A lower limit value may be set for the settable range of the mill outlet temperature T1. Coal properties are, for example, the O/C value (molar ratio of oxygen and carbon).

Thus, the boiler efficiency is improved by increasing the mill outlet temperature T1 to the upper limit of the settable range.

FIG. 6 is a diagram showing an example of the relationship between mill outlet temperature and boiler efficiency. FIG. 6 shows the relationship between the mill outlet temperature and the outlet gas temperature of the air heater 42, and the relationship between the mill outlet temperature and boiler efficiency. Increasing the mill outlet temperature setting increases the opening of the hot air dampers W1, W2, W3, W4, W5 and the cold air dampers R1, R2, R3, R4, R5 in order to increase the mill inlet temperature. The control device 220 controls to decrease the opening of the . By this operation, the flow rate of primary air (hot air) passing through the air heater 42 increases (the flow rate ratio of cold air bypassing the air heater 42 decreases), and the amount of heat exchanged between the primary air and exhaust gas in the air heater 42 increases. . As a result, the air heater outlet gas temperature is reduced, the exhaust gas loss, which is the amount of heat carried out by the exhaust gas to the outside of the boiler system, is reduced, and the boiler efficiency is improved.

Next, the case of adjusting the carrier gas (primary air) flow rate will be described.
The regulator 203 reduces the primary air flow rate to improve boiler efficiency. Specifically, the hot air dampers W1, W2, W3, W4 and W5 and the cold air dampers R1, R2, R3, R4 and R5 are operated in the closing direction up to the lower limit of the settable range. When the flow rate of the primary air decreases, in order to secure the total air flow rate set according to the fuel supply amount to the boiler 10, the FDF damper D2 is operated in the opening direction to increase the secondary air flow rate. performed by the device 200; This operation increases the flow rate of the secondary air passing through the air heater 42 and increases the amount of heat exchanged between the secondary air and the exhaust gas in the air heater 42 . As a result, the outlet gas temperature of the air heater 42 is reduced, the loss of exhaust gas, which is the amount of heat carried out by the exhaust gas to the outside of the boiler system, is reduced, and the boiler efficiency is improved. In addition, when the primary air flow rate decreases, in order to secure the amount of heat supplied to the mill (to maintain the mill outlet temperature at the set value), the mill inlet temperature is increased. Specifically, the hot air damper W1, Control device 200 performs control to increase the opening degrees of W2, W3, W4, and W5 and decrease the opening degrees of cold air dampers R1, R2, R3, R4, and R5. By this operation, the flow rate of the primary air (hot air) passing through the air heater 42 increases (the flow rate of cool air, which is the primary air bypassing the air heater 42, decreases), and the primary air (hot air) in the air heater 42 increases. ) and the heat exchange amount of exhaust gas increases. As a result, the outlet gas temperature of the air heater 42 is reduced, the loss of exhaust gas, which is the amount of heat carried out by the exhaust gas to the outside of the boiler system, is reduced, and the boiler efficiency is improved.

The settable range of the carrier gas flow rate is the solid-gas two-phase flow of the pulverized fuel and the carrier gas passing through the burners 21, 22, 23, 24, and 25 and the pulverized coal supply pipes 26, 27, 28, 29, and 30. The lower limit of the carrier gas flow rate is set according to at least one of the settling velocity and the dryness of the pulverized fuel in the mill. Dryness means that the temperature at the outlet of the mill can be kept above the lower limit (desired drying is achieved). An upper limit value may be set for the settable range of the carrier gas flow rate.

By controlling in this manner, the flow rate of air (hot air and secondary air that are part of the primary air) passing through the air heater 42 increases, and the amount of heat exchange between the primary air and exhaust gas in the air heater 42 increases. As a result, the exhaust gas temperature at the outlet of the air heater 42 is reduced, the loss of the exhaust gas, which is the amount of heat carried out by the exhaust gas to the outside of the boiler system, is reduced, and the boiler efficiency is improved. Therefore, the boiler efficiency is improved by reducing the carrier gas flow rate to the lower limit of the settable range.

In addition, it is confirmed that the opening of the cold air dampers R1, R2, R3, R4, and R5 is equal to or higher than the control lower limit value (for example, 5%), and the cold air dampers R1 and R2 are turned off before the flow rate decreases to the lower limit value. , R3, R4, and R5 reach the control lower limit, it is preferable to end the control for decreasing the carrier gas flow rate. The control lower limit is the minimum required damper opening to stably control the carrier gas temperature and flow rate.

FIG. 7 is a diagram showing an example of the relationship between the carrier gas flow rate and the boiler efficiency. FIG. 7 shows the relationship between the carrier gas flow rate and the required mill inlet air temperature, the relationship between the carrier gas flow rate and the outlet gas temperature of the air heater 42, and the relationship between the carrier gas flow rate and the boiler efficiency. . As shown in the relationship between the carrier gas flow rate and the required mill inlet air temperature, there is a point P1 at which the cold air dampers R1, R2, R3, R4, and R5 are at their lower limits. be lowered. This reduction in carrier gas flow rate improves boiler efficiency.

Next, the case of adjusting the boiler outlet oxygen concentration will be described.
Adjustment unit 203 reduces the boiler outlet oxygen concentration to improve boiler efficiency. Specifically, the boiler outlet oxygen concentration is decreased by operating in the direction of decreasing the amount of air supplied to the boiler 10 to the lower limit of the settable range. The amount of air supplied to the boiler 10 is manipulated, for example, by manipulating the FDF damper D2.

As for the settable range of the boiler outlet oxygen concentration M1, the lower limit value is set based on the predetermined value of the boiler outlet oxygen concentration M1. An upper limit value may be set for the settable range of the boiler outlet oxygen concentration M1. The specified value of the boiler outlet oxygen concentration M1 is preset, for example, so that the unburned content in the ash is equal to or less than a preset upper limit value.

By lowering the setting of the boiler outlet oxygen concentration M1, the amount of air supplied to the boiler 10 is reduced, and as a result, the amount of flue gas discharged from the boiler is reduced, and flue gas loss can be reduced. In this way, the boiler efficiency is improved by reducing the boiler outlet oxygen concentration M1 to the lower limit of the settable range.

If the boiler outlet oxygen concentration M1 is reduced, effects such as an increase in the carbon monoxide concentration in the exhaust gas and a decrease in the wind box differential pressure P1 occur. An increase in the concentration of carbon monoxide in exhaust gas is caused by incomplete combustion of fuel, and boiler efficiency decreases. Also, a decrease in the air box differential pressure P1 may cause combustion instability in the burner. For this reason, the upper limit of the carbon monoxide concentration and the lower limit of the wind box differential pressure P1 are set in advance. When the box differential pressure P1 reaches the lower limit, it is preferable to end the control for lowering the boiler outlet oxygen concentration M1.

FIG. 8 is a diagram showing an example of the relationship between boiler outlet oxygen concentration and boiler efficiency. In FIG. 8, the relationship between the boiler outlet oxygen concentration (economy outlet oxygen concentration) and the amount of exhaust gas, the relationship between the boiler outlet oxygen concentration and the carbon monoxide concentration in the exhaust gas, the boiler outlet oxygen concentration and the unburned ash The relationship between the boiler efficiency and the exhaust gas amount, the relationship between the boiler efficiency and the carbon monoxide concentration in the exhaust gas, and the relationship between the boiler efficiency and the unburned content are shown. Thus, reducing the boiler outlet oxygen concentration improves boiler efficiency.

Next, the case of adjusting the auxiliary gas flow rate will be described.
The regulator 203 reduces the auxiliary gas flow rate to improve boiler efficiency. Specifically, the auxiliary gas is supplied to the stopped mill (for example, mill 31), and at this time, the cold air damper (R1) is open and the hot air damper (W1) is closed. The gas becomes air from the cold air damper (R1). Therefore, the auxiliary gas flow rate is decreased by operating the cold air damper (R1) corresponding to the mill that is not operating in the closing direction to the lower limit of the settable range.

Auxiliary gas is supplied to an inactive mill (eg, mill 31) and then to a corresponding extinguished burner (eg, burner 21). Insufficient auxiliary gas may result in insufficient burner cooling, which may result in burnout of the burner. For this reason, the lower limit value of the settable range of the auxiliary gas flow rate is set based on the upper limit temperature for use of the burner. An upper limit value may be set for the settable range of the auxiliary gas flow rate. The upper limit temperature for use of the burner varies depending on the specifications of the burner (for example, the material and shape used), and the flow rate of the auxiliary gas required for cooling the burner varies depending on the load of the boiler 10 (heat load in the furnace 11). Become. Therefore, it is preferable to set the lower limit value of the auxiliary gas flow rate according to the load of the boiler 10 by installing a thermocouple or the like (not shown) in the burner to monitor the metal temperature. If the thermocouple cannot be installed (when the temperature cannot be monitored), for example, the lower limit value of the auxiliary gas flow rate corresponding to the upper limit temperature of the burner can be set according to the load of the boiler 10 (heat load of the furnace 11). Different settings are possible.

When the auxiliary gas flow rate branched from the primary air (cold air) bypassing the air heater 42 decreases in this way, the FDF damper is required to ensure the total air flow rate set according to the fuel supply amount to the boiler 10. The control device 200 operates D2 in the opening direction to increase the secondary air flow rate. This operation increases the flow rate of the secondary air passing through the air heater 42 and increases the amount of heat exchanged between the secondary air and the exhaust gas in the air heater 42 . As a result, the air heater outlet gas temperature is reduced, the exhaust gas loss, which is the amount of heat carried out by the exhaust gas to the outside of the boiler system, is reduced, and the boiler efficiency is improved.

FIG. 9 is a diagram showing an example of the relationship between auxiliary gas flow rate and boiler efficiency. FIG. 9 is a diagram showing the relationship between the auxiliary gas flow rate and the metal temperature of the extinguishing burner, the relationship between the auxiliary gas flow rate and the exit gas temperature of the air heater 42, and the relationship between the auxiliary gas flow rate and the boiler efficiency. This reduction in auxiliary gas flow improves boiler efficiency.

Next, an example of operation parameter adjustment processing by the control device 200 described above will be described with reference to FIG. FIG. 10 is a flow chart showing an example of the procedure of the operating parameter adjustment process according to this embodiment. The flow shown in FIG. 10 is executed, for example, when there is an instruction to start adjustment control for improving boiler efficiency.

In this embodiment, since the priority order of execution is set in the operating parameters, accordingly, the oxygen concentration at the boiler outlet is set to number A = 1, the mill outlet temperature is set to number A = 2, and the carrier gas is set to number A = 3. It is assumed that the auxiliary gas flow rate is set as the flow rate, number A=4.

First, the operating parameter number A is set to 1 (S101).

Next, it is determined whether or not the operating parameter of the set number can be adjusted (S102). Specifically, it is determined whether or not the difference between the current operating parameter value and the limit value of the settable range is equal to or greater than a threshold.

If the adjustment is possible (YES determination in S102), adjustment processing is executed for the operating parameter of the set number (S103).

If the adjustment is not possible (NO determination in S102), S105 is executed.

Next, after adjusting the operating parameters, the boiler efficiency improvement amount is evaluated (S104). The evaluated boiler efficiency improvement amount may be notified to the operator of the power plant 1, for example.

Next, it is determined whether or not the operating parameter number A is the final number (4 in this embodiment) (S105).

If the operating parameter number A is not the final number (NO determination in S105), 1 is added to the number A in S106 (A=A+1), and S102 is executed. As a result, the operation parameter number A=2 is processed again from S102.

If the operating parameter number A is the final number (YES determination in S105), the process is terminated.

Note that the above process may be repeatedly executed until the target boiler efficiency improvement effect is obtained.

By executing the processing as in the above flow, the adjustment processing is executed for each operating parameter according to the order of priority. That is, as shown in FIG. 11, first, the boiler outlet oxygen concentration is adjusted. Specifically, the boiler outlet oxygen concentration is reduced within a settable range. And then adjust the mill outlet temperature. Specifically, the mill exit temperature is increased within a settable range. Then, the carrier gas flow rate is adjusted. Specifically, the carrier gas flow rate is reduced within a settable range. Then, the auxiliary gas flow rate is adjusted. Specifically, the auxiliary gas flow rate is reduced within a settable range.

In this way, the adjustment processing for each operating parameter is executed according to the order of priority, and the boiler efficiency is improved.

As described above, according to the operating state improvement system, the power plant, the operating state improvement method, and the operating state improvement program according to the present embodiment, it is calculated from the operating state value of the boiler 10 within the settable range Adjusting operating parameters based on a predetermined performance index. Therefore, it is possible to improve the evaluation index by adjusting the operating parameters. Since the operating parameters are adjusted within the settable range, it is possible to prevent the operating parameters for improving the evaluation index from being set to inappropriate values. By using the improvement amount of the boiler efficiency as the evaluation index, it becomes possible to improve the boiler efficiency by adjusting the operating parameters.

In addition, compared to a method of optimizing operating parameters using AI, for example, it can be expected to reduce introduction costs and omit verification of reproducibility using a model.

Also, based on the oxygen concentration of the combustion gas discharged from the boiler 10 and the temperature of the combustion gas discharged from the air preheater 42 that exchanges heat between the combustion gas and the air supplied to the boiler 10 , the improvement amount of the boiler efficiency can be efficiently calculated.

Further, by setting the operating parameters based on the degree of influence on the evaluation index, it is possible to effectively adjust the operating parameters for the evaluation index. By adjusting the operating parameters in descending order of the degree of influence on the evaluation index, it is possible to preferentially adjust the operation parameters with the greatest degree of influence and efficiently adjust the evaluation index.

In addition, by using any one of the mill outlet temperature, carrier gas flow rate, boiler outlet oxygen concentration, and auxiliary gas flow rate as operating parameters, it is possible to effectively adjust the evaluation index (boiler efficiency). becomes. By adjusting the operating parameters in the order of boiler outlet oxygen concentration, mill outlet temperature, carrier gas flow rate, and auxiliary gas flow rate, priority is given to adjusting operating parameters that have a large impact on the evaluation index (boiler efficiency). It can be carried out. Therefore, it is possible to efficiently adjust the evaluation index (boiler efficiency). When adjusting the mill outlet temperature, increase the mill outlet temperature, when adjusting the carrier gas flow rate, decrease the carrier gas flow rate, when adjusting the boiler outlet oxygen concentration, decrease the boiler outlet oxygen concentration, By reducing the auxiliary gas flow rate when adjusting the gas flow rate, it is possible to efficiently adjust the evaluation index (boiler efficiency).

[Second embodiment]
Next, an operating state improving system, a power plant, an operating state improving method, and an operating state improving program according to a second embodiment of the present disclosure will be described.
In the above-described first embodiment, the case where the priority order is set in advance and the adjustment process is executed for each operating parameter has been described. A case in which the order of execution is determined based on the current value) will be described. Hereinafter, the operating state improvement system, the power plant, the operating state improving method, and the operating state improving program according to the present embodiment will be mainly described with respect to the differences from the first embodiment.

FIG. 12 is a flow showing the operating parameter adjustment process in this embodiment. In this embodiment, a case where the mill outlet temperature, the carrier gas flow rate, the boiler outlet oxygen concentration, and the auxiliary gas flow rate are used as the operating parameters will be described as an example.

In FIG. 12, the auxiliary codes for the operating parameters are a for the mill outlet temperature, b for the carrier gas flow rate, c for the boiler outlet oxygen concentration, and d for the auxiliary gas flow rate.

First, an adjustable amount is calculated (S201). The adjustable amount is the difference between the limit value in the settable range and the current value for each operating parameter. In S201, an adjustable amount (difference) is calculated for each operating parameter. Specifically, Sa is calculated as an adjustable amount for the mill outlet temperature, Sb as an adjustable amount for the carrier gas flow rate, Sc as an adjustable amount for the boiler outlet oxygen concentration, and Sd as an adjustable amount for the auxiliary gas flow rate. be.

Next, an expected value (expected improvement value) of the amount of improvement in boiler efficiency is calculated (S202). That is, evaluation is performed in the evaluation unit 202 . The expected improvement value is the expected value (estimated value) of the amount by which the boiler efficiency is improved when the operating parameter is manipulated by the adjustable amount. The expected improvement value is calculated using a predetermined function with the adjustable amount as a variable. Functions are set in advance. Further, the method is not limited to the method using a function as long as the expected improvement value is calculated from the adjustable amount. The function may be a theoretical formula (design formula) or an empirical formula based on past operating data.

Specifically, the expected improvement value is calculated as ΔEa=fa(Sa) corresponding to Sa, which is the adjustable amount of the mill outlet temperature. Here, fa is a function for calculating the expected improvement value ΔEa from the adjustable amount Sa. The expected improvement value is calculated as ΔEb=fb(Sb) corresponding to Sb, which is the adjustable amount of the carrier gas flow rate. The expected improvement value is calculated as ΔEc=fc(Sc) corresponding to Sc, which is the adjustable amount of the boiler outlet oxygen concentration. The expected improvement value is calculated as ΔEd=fd(Sd) corresponding to Sd, which is the adjustable amount of the auxiliary gas flow rate.

Next, the operation parameters to be adjusted are selected (S203). Specifically, it is determined whether or not the largest expected improvement value (MAX (ΔEa, ΔEb, ΔEc, ΔEd)) among the expected improvement values corresponding to the operating parameters is greater than the threshold value (Eth(i)). . That is, in the determination process of S203, the determination process of MAX (ΔEa, ΔEb, ΔEc, ΔEd)>Eth(i) is performed. Note that i is the number of repetitions, and 1 is set as an initial value.

If S203 is a negative determination (NO determination), S205 is executed.

If the determination in S203 is affirmative (YES determination), the operation parameter corresponding to the largest improvement expected value (MAX (ΔEa, ΔEb, ΔEc, ΔEd)) among the improvement expected values corresponding to each operation parameter An adjustment process is executed (S204). In this way, the adjustment process is executed for the operating parameter having a large degree of influence (improvement expected value) on the evaluation index (boiler efficiency).

Then, it is determined whether or not the processing is finished (S205). The end of processing is determined by whether or not i, which is the number of repetitions, has reached a predetermined upper limit. For example, if the upper limit is set to 4, the processing from S201 to S205 will be performed four times. Note that S205 may be determined based on an end instruction from an operator or the like.

If the process ends (YES in S205), the process ends. On the other hand, if the process has not been completed (NO determination in S205), a process of adding 1 to i (i=i+1) is performed (S206). Then, the process is executed again from S201.

Note that when i changes, the value of Eth(i) changes. Specifically, Eth(i) preferably decreases as i increases. When decreasing Eth(i), the value is subtracted, for example, by a predetermined amount. Note that Eth(i) may be a fixed value as Eth instead of using i as a variable.

By performing the processing in this manner, the adjustment processing for improving the boiler efficiency is executed from the operating parameter having the largest improvement expected value as the degree of influence. This improves boiler efficiency.

As described above, according to the operating state improvement system, the power plant, the operating state improvement method, and the operating state improvement program according to the present embodiment, the operation parameter adjustment process is executed based on the degree of impact on the boiler efficiency. Therefore, it is possible to effectively improve the boiler efficiency.

The present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. In addition, it is also possible to combine each embodiment. That is, it is also possible to combine the first embodiment and the second embodiment described above.

The operating state improving system, the power plant, the operating state improving method, and the operating state improving program described in each of the embodiments described above are grasped as follows, for example.
In the operating condition improvement system (200) according to the present disclosure, a settable range is set in advance for a predetermined operating parameter, and the settable range is set based on a predetermined evaluation index based on the operating condition of the boiler (10). An adjustment unit (203) is provided for adjusting the operating parameter within a range.

According to the operating state improvement system (200) according to the present disclosure, the operating parameters are adjusted based on the predetermined evaluation index based on the operating state of the boiler (10) within a settable range. Therefore, it is possible to improve the evaluation index by adjusting the operating parameters. Since the operating parameters are adjusted within the settable range, it is possible to prevent the operating parameters for improving the evaluation index from being set to inappropriate values. For example, compared to a method of optimizing operating parameters using AI, it can be expected to reduce the introduction cost of AI and omit verification of reproducibility using a model.

In the operating state improvement system (200) according to the present disclosure, the evaluation index may be the amount of improvement in boiler efficiency.

According to the operating state improvement system (200) according to the present disclosure, by using the amount of improvement in boiler efficiency as an evaluation index, it is possible to improve boiler efficiency by adjusting operating parameters.

In the operating state improvement system (200) according to the present disclosure, the improvement amount of the boiler efficiency is calculated based on a change in a predetermined operating state value before and after the adjustment of the operating parameter, and the operating state value is calculated based on the boiler oxygen concentration of the combustion gas discharged from (10) and the content of said combustion gas discharged from an air preheater (42) that exchanges heat between said combustion gas and the air supplied to said boiler (10) It may be the temperature.

According to the operating state improvement system (200) according to the present disclosure, heat exchange is performed between the oxygen concentration of the combustion gas discharged from the boiler (10) and the air supplied to the combustion gas and the boiler (10). The amount of improvement in boiler efficiency can be efficiently calculated based on the temperature of the combustion gas discharged from the air preheater (42).

The driving condition improvement system (200) according to the present disclosure may preset the driving parameter based on the degree of influence on the evaluation index.

According to the driving condition improvement system (200) according to the present disclosure, by setting the driving parameters based on the degree of influence on the evaluation index, it is possible to effectively adjust the driving parameters for the evaluation index.

In the driving condition improvement system (200) according to the present disclosure, when the adjusting unit (203) uses a plurality of the driving parameters, the driving parameters are adjusted in descending order of influence on the evaluation index. good.

According to the operating condition improvement system (200) according to the present disclosure, by adjusting the operating parameters in order from the one having the greatest influence on the evaluation index, the operating parameters having the greatest influence are preferentially adjusted, and efficiently Adjustments can be made to the evaluation index.

The operating condition improvement system (200) according to the present disclosure sets the operating parameters as the mill outlet temperature, which is the temperature of the fluid discharged from the mills (31, 32, 33, 34, 35), the mill (31, 32, 33) , 34, 35), a carrier gas flow rate that is the flow rate of the carrier gas supplied to the boiler (10), a boiler outlet oxygen concentration that is the oxygen concentration of the combustion gas discharged from the boiler (10), and the boiler (10) at least one of auxiliary gas flow rates, which are the flow rates of the auxiliary gas supplied to the mills (31, 32, 33, 34, 35) during stoppage when a plurality of the mills (31, 32, 33, 34, 35) are provided in the may be

According to the operating condition improvement system (200) according to the present disclosure, by using any one of the mill outlet temperature, the carrier gas flow rate, the boiler outlet oxygen concentration, and the auxiliary gas flow rate as the operating parameters, It is possible to make adjustments to the evaluation index (boiler efficiency).

In the operating condition improving system (200) according to the present disclosure, the adjustment unit (203) uses the mill outlet temperature, the carrier gas flow rate, the boiler outlet oxygen concentration, and the auxiliary gas flow rate as the operating parameters. In this case, the operating parameters may be adjusted in the order of the boiler outlet oxygen concentration, the mill outlet temperature, the carrier gas flow rate, and the auxiliary gas flow rate.

According to the operating condition improvement system (200) according to the present disclosure, the evaluation index (boiler efficiency ) can be preferentially adjusted. Therefore, it is possible to efficiently adjust the evaluation index (boiler efficiency).

In the operating condition improving system (200) according to the present disclosure, the adjusting unit (203) increases the mill outlet temperature when adjusting the mill outlet temperature, and increases the conveying gas flow rate when adjusting the conveying gas flow rate. The boiler outlet oxygen concentration may be decreased when the auxiliary gas flow rate is decreased and the boiler outlet oxygen concentration is adjusted, and the auxiliary gas flow rate may be decreased when the auxiliary gas flow rate is adjusted.

According to the operating condition improvement system (200) according to the present disclosure, the mill outlet temperature is increased when adjusting the mill outlet temperature, the carrier gas flow rate is decreased when the carrier gas flow rate is adjusted, and the boiler outlet oxygen By reducing the boiler outlet oxygen concentration when adjusting the concentration and reducing the auxiliary gas flow rate when adjusting the auxiliary gas flow rate, it is possible to efficiently adjust the evaluation index (boiler efficiency).

In the driving state improving system (200) according to the present disclosure, when using a plurality of the driving parameters, the adjustment unit (203) is configured to adjust the driving Parameters may not be adjusted.

According to the operating state improvement system (200) according to the present disclosure, it is possible to efficiently adjust the evaluation index (boiler efficiency).

In the driving state improvement system (200) according to the present disclosure, the adjustment unit (203) may repeatedly adjust each of the driving parameters in the order.

According to the driving condition improvement system (200) according to the present disclosure, by repeatedly adjusting each driving parameter, it becomes possible to more reliably adjust the evaluation index.

A power plant (1) according to the present disclosure comprises a boiler (10), a turbine (110) driven by steam generated by the boiler, and the operating condition improvement system (200) described above.

In the operating state improvement method according to the present disclosure, a settable range is preset for a predetermined operating parameter, and within the settable range based on a predetermined evaluation index based on the operating state of the boiler (10) and adjusting the operating parameters.

In the operating state improvement program according to the present disclosure, a settable range is preset for a predetermined operating parameter, and within the settable range based on a predetermined evaluation index based on the operating state of the boiler (10) A computer is caused to execute a process of adjusting the operating parameter.

1: Boiler power plant (power plant)
10: Coal-fired boiler (boiler)
11: Furnace 12: Combustion device 13: Combustion gas passage 14: Flue 21: Burner 22: Burner 23: Burner 24: Burner 25: Burner 26: Pulverized coal supply pipe 27: Pulverized coal supply pipe 28: Pulverized coal supply pipe 29 : Pulverized coal supply pipe 30 : Pulverized coal supply pipe 31 : Mill 32 : Mill 33 : Mill 34 : Mill 35 : Mill 36 : Wind box 37 : Air duct 38A : Forced draft fan 38B : Primary air fan 39 : Additional air port 40: Additional air duct 41: Gas duct 42: Air heater (air preheater)
43: denitration device 44: dust collector 46: desulfurization device 50: chimney 101: furnace wall 102: first superheater (superheater)
103: Second superheater (superheater)
104: Third superheater (superheater)
105: First reheater (reheater)
106: Second reheater (reheater)
107: Economizer 110: Steam turbine 111: High pressure turbine 112: Intermediate pressure turbine 113: Low pressure turbine 114: Condenser 115: Generator 122: Low pressure feed water heater 123: Boiler feed water pump 124: High pressure feed water heater 126: Brackish water separation Instrument 127: Steam separator drain tank 200: Control device (operating condition improvement system)
201: adjustment confirmation unit 202: evaluation unit 203: adjustment unit 1100: CPU
1200: ROM
1300: RAM
1400: Hard disk drive 1500: Communication unit 1800: Bus CA1: Area CA2: Area L1: Water supply line L2: Drain water line L3: Steam line L4: Line L5: Steam line L6: Circulation line R1-R5: Cold air damper W1- W5: hot air damper

Claims (13)

A settable range is set in advance for a predetermined operating parameter, and the operating state improvement includes an adjusting unit that adjusts the operating parameter within the settable range based on a predetermined evaluation index based on the operating state of the boiler. system. 2. The operating condition improvement system according to claim 1, wherein said evaluation index is an improvement amount of boiler efficiency. The improvement amount of the boiler efficiency is calculated based on a change in a predetermined operating state value before and after the adjustment of the operating parameter,
The operating state value includes the oxygen concentration of the combustion gas discharged from the boiler and the temperature of the combustion gas discharged from an air preheater that exchanges heat between the combustion gas and the air supplied to the boiler. 3. The driving condition improvement system according to claim 2. 4. The driving condition improving system according to any one of claims 1 to 3, wherein the driving parameter is preset based on the degree of influence on the evaluation index. 5. The operating condition improving system according to claim 4, wherein when a plurality of said operating parameters are used, said adjustment unit adjusts said operating parameters in descending order of influence on said evaluation index. The operating parameters are the mill outlet temperature, which is the temperature of the fluid discharged from the mill, the carrier gas flow rate, which is the flow rate of the carrier gas supplied to the mill, and the oxygen concentration of the combustion gas discharged from the boiler. It is at least one of a boiler outlet oxygen concentration and an auxiliary gas flow rate which is a flow rate of the auxiliary gas supplied to the stopped mill when a plurality of the mills are provided for the boiler. 2. The driving condition improvement system according to 2. When the mill outlet temperature, the carrier gas flow rate, the boiler outlet oxygen concentration, and the auxiliary gas flow rate are used as the operating parameters, the adjustment unit adjusts the boiler outlet oxygen concentration, the mill outlet temperature, the carrier gas flow rate, and the 7. The operating condition improving system according to claim 6, wherein each of said operating parameters is adjusted in the order of the auxiliary gas flow rate and said auxiliary gas flow rate. The adjustment unit increases the mill outlet temperature when adjusting the mill outlet temperature, decreases the carrier gas flow rate when adjusting the carrier gas flow rate, and adjusts the boiler outlet oxygen concentration. 8. The operating state improving system according to claim 7, wherein the auxiliary gas flow rate is reduced when the boiler outlet oxygen concentration is reduced immediately and the auxiliary gas flow rate is adjusted. 9. The method according to any one of claims 1 to 8, wherein, when a plurality of the operating parameters are used, the adjustment unit does not adjust the operating parameter for which the adjustable amount of the operating parameter in the settable range is smaller than a threshold. The operating condition improvement system according to any one of claims 1 to 3. The operating state improving system according to claim 5 or 7, wherein the adjustment unit repeatedly adjusts each of the operating parameters in the order. a boiler;
a turbine driven by the steam generated by the boiler;
The driving condition improvement system according to any one of claims 1 to 10;
A power plant with a A settable range is set in advance for a predetermined operating parameter, and an operating state improving method comprising the step of adjusting the operating parameter within the settable range based on a predetermined evaluation index based on the operating state of the boiler. . A settable range is set in advance for a predetermined operating parameter, and the computer executes processing for adjusting the operating parameter within the settable range based on a predetermined evaluation index based on the operating state of the boiler. operating condition improvement program.

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