JP2012122640A - Method for computing boiler room efficiency, and method for computing power generation terminal efficiency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for computing boiler room efficiency that can accurately determine power generation terminal efficiency even with boiler room efficiency computed by a loss method by multiplying it by turbine room efficiency.SOLUTION: When computing the boiler room efficiency by subtracting a loss amount from a heat input amount to a boiler in a thermal power plant that generates power by guiding steam generated in the boiler 11 to turbines 15, 17, 18 and driving a generator connected to the turbines, heat input to the turbine room side viewed from the turbine room side is set as plus, while heat output from the turbine room side to the boiler room side is set as minus, and heat output from the turbine room side to the boiler room side is regarded as a loss amount of the boiler and subtracted from the heat input amount to the boiler to compute boiler room efficiency.

Description

  The present invention relates to a boiler room efficiency calculation method for calculating boiler room efficiency of a thermal power plant and a power generation end efficiency calculation method for calculating power generation efficiency of a thermal power plant.

  Generally, in order to operate a thermal power plant efficiently in a thermal power plant, it is necessary to accurately grasp the power generation end efficiency of the thermal power plant. The power generation end efficiency ηp is obtained by the product of the turbine chamber efficiency ηt and the boiler chamber efficiency ηb as shown in the equation (1).

ηp = ηt × ηb (1)
Further, the turbine chamber efficiency ηt (%) is obtained by dividing the turbine heat output Qm by the turbine heat input Qi as shown in the equation (2) by the heat input / output method.

ηt (%) = (Qm ÷ Qi) × 100 (2)
On the other hand, the boiler room efficiency ηb (%) is calculated by the heat input / output method or the loss method. The boiler room efficiency ηb1 (%) in the heat input / output method is obtained by dividing the boiler heat output Qo by the boiler heat input Qf, as shown in Equation (3). The boiler room efficiency ηb2 (%) in the loss method Is obtained by dividing a value (Qf−Qr) obtained by subtracting the boiler loss Qr from the boiler heat input Qf by the boiler heat input Qf, as shown in the equation (4).

ηb1 (%) = (Qo ÷ Qf) × 100 (3)
ηb2 (%) = {(Qf−Qr) ÷ Qf} × 100
= 1− (Qr ÷ Qf) × 100 (4)
Therefore, when the power generation end efficiency ηp is obtained, when the boiler chamber efficiency ηb is the boiler chamber efficiency ηb1 (%) of the input / output heat method shown by the equation (3), the input / output heat method shown by the equation (5) When the boiler chamber efficiency ηb is the loss chamber efficiency ηb2 (%) of the loss method expressed by the equation (4), the generation end efficiency ηp2 by the loss method expressed by the equation (6) is obtained. .

ηp1 (%) ＝ ηt (%) × ηb1 (%) ÷ 100 (5)
ηp2 (%) ＝ ηt (%) × ηb2 (%) ÷ 100 (6)
The power generation end efficiency ηp1 by the heat input / output method and the power generation end efficiency ηp2 by the loss method should theoretically be the same value, but there are problems in measurement accuracy and the basic calorific value calculation between the input / output heat method and the loss method It is not always the same value due to the difference in the way of thinking.

  As described in JIS, boiler room efficiency has a smaller measurement error and higher accuracy in the loss method. In addition, the measurement error of the boiler heat input is large in coal-fired power, and the accuracy is reduced in the heat input / output method. Therefore, at present, the power generation end efficiency ηp2 shown in equation (6) is often obtained.

Here, the boiler efficiency of the boiler that burns the fuel is calculated by the loss method, the turbine efficiency of the steam turbine driven by the steam from the boiler is calculated by the heat balance analysis method, and the boiler efficiency and the turbine efficiency are multiplied. In other words, the plant efficiency of a thermal power plant is calculated with high accuracy (see, for example, Patent Document 1).

JP 2007-231808 A

  However, the thing of patent document 1 does not correct the difference in the basic concept of calorific value calculation between the heat input / output method and the loss method. The difference between the power generation efficiency ηp1 of the heat input / output method due to the difference in the concept of calorie calculation and the power generation efficiency ηp2 of the loss method applies not only to coal-fired power but also to gas-fired and oil-fired power. The reason is as follows.

  Consider a case where the steam supply source of steam used in steam-using equipment such as a steam air preheater (SAH) is on the turbine chamber side and the location where steam is used is on the boiler chamber side. Considering the heat input / output method, boiler heat output Qo1 of the heat input / output method is expressed by equation (7).

Qo1 = (QMS + QHR-QCR-QFW) -Qsah + Qsahd + Qmc (7)
QMS: Main steam calorie, QHR: High temperature reheat steam calorie, QCR: Low temperature reheat steam calorie, QFW: Feed water calorie, Qsah: SAH steam calorie, Qsahd: SAH drain calorie, Qmc: Supply water calorie The boiler heat output Qo1 is the turbine heat input Qi, and the steam of the steam air preheater (SAH) is taken from the turbine bleed, so the SAH steam heat quantity Qsah is subtracted from the turbine heat input Qi (boiler output heat Qo1). Yes. Further, since the SAH drain heat quantity Qsahd and the makeup water heat quantity Qmc are returned to the turbine chamber, they are added to the turbine heat input Qi (boiler output heat Qo1).

  Therefore, the boiler chamber efficiency ηb1 (%) of the heat input / output method is expressed by equation (8) by substituting the boiler heat output Qo1 in equation (7) for the boiler heat output Qo in equation (3).

ηb1 (%) = [{(QMS + QHR−QCR−QFW) −Qsah + Qsahd + Qmc} ÷ Qf] × 100 (8)
Thus, in the heat input / output method, when the steam supply source of the steam used in the steam using device is on the turbine chamber side, the amount of heat is subtracted from the boiler heat output Qo1 (turbine heat input Qi).

  On the other hand, considering the loss method, these heat amounts are treated as heat recovery, so the boiler room efficiency ηb2 (%) of the loss method is expressed by equation (9).

ηb2 (%) = 100− (L1 + L2 + ...− L11 ...) (9)
L1: Dry exhaust gas loss, L2: Hydrogen loss in fuel, ~ L11: SAH heat recovery.

  Thus, in the loss method, when the steam supply source of the steam used in the steam-using device is on the turbine chamber side, the boiler output heat Qo2 is increased assuming that the amount of heat is recovered by the boiler. That is, in the loss method, if SAH steam is supplied from the turbine chamber, it is treated not as a loss but as a recovery of the amount of heat because heat is input to the boiler.

  Therefore, when the power generation end thermal efficiency ηp is obtained by the equation (1), considering only the input / output heat method, the overall input / output heat is maintained even if the turbine chamber efficiency ηt and the boiler chamber efficiency ηb vary depending on the calculation method. Because there is no problem.

  For example, in the state where SAH steam is supplied from the turbine chamber and the amount of steam increases (= SAH steam heat amount increases), an increase in SAH steam heat amount means a decrease in turbine input heat Qi, It also means a reduction in boiler heat output Qo in the boiler room. When the generator output is constant (turbine heat output Qm is constant), the decrease in turbine heat input Qi appears as an increase in turbine chamber efficiency ηt from equation (2). On the other hand, since the amount of heat consumed by the fuel is constant (the boiler heat input Qf is constant) and the boiler output heat Qo is reduced, the boiler chamber efficiency ηb1 is reduced from the equation (3). Thus, considering only the heat input / output method, the power generation end efficiency ηp1 is constant even if these phenomena occur, and there is no problem in that sense.

  However, the calculation based on the idea of the loss method is not valid. According to the current loss method calculation, the SAH steam calorie L11 is treated as heat recovery, so that the boiler heat input Qf increases as the SAH steam increases. Therefore, as shown in the equation (4), the boiler chamber efficiency ηb2 of the loss method increases. The phenomenon considered only by the above-mentioned heat input / output method, that is, the opposite result of the decrease in the boiler chamber efficiency ηb1 due to the increase of the SAH steam is brought about. The power generation efficiency ηp2 of the loss method becomes a large value.

  An object of the present invention is a boiler chamber efficiency calculation method and a power generation end efficiency calculation capable of obtaining a power generation end efficiency which is the same as the heat input / output method by multiplying the turbine chamber efficiency even with the boiler chamber efficiency calculated by the loss method. Is to provide a method.

  The boiler room efficiency calculation method according to the first aspect of the present invention is the loss from the amount of heat input to the boiler of a thermal power plant that generates steam by introducing steam generated in the boiler to the turbine and driving the generator connected to the turbine. In the boiler chamber efficiency calculation method based on the loss method that calculates the boiler chamber efficiency by subtracting the amount, the heat input to the turbine chamber side as viewed from the turbine chamber side is positive, and the boiler chamber efficiency from the turbine chamber side to the boiler chamber side The boiler chamber efficiency is calculated by subtracting the heat output from the turbine chamber side to the boiler chamber side from the amount of heat input to the boiler as a loss amount of the boiler.

  The boiler room efficiency calculation method according to the invention of claim 2 is supplied from the turbine chamber side as a loss amount of the boiler when the thermal power plant is a gas thermal power plant in the invention of claim 1. The amount of heat is a reheater spray water heat amount for adjusting the temperature of the reheater.

  The boiler room efficiency calculation method according to the invention of claim 3 is supplied from the turbine chamber side as a loss amount of the boiler when the thermal power plant is an oil thermal power plant in the invention of claim 1. The calorific value is the steam calorific value of the steam type air preheater that preheats the air, the steam calorific value of the evaporator that warms the fuel oil, the atomized steam calorie that sprays the fuel oil, and the reheater spray water calorie that adjusts the reheater temperature It is characterized by being.

  The boiler room efficiency calculation method according to the invention of claim 4 is supplied from the turbine chamber side as the loss amount of the boiler when the thermal power plant is a coal-fired power plant in the invention of claim 1. The amount of heat is a soot blower steam heat amount, a steam heat amount for a gas gas heat exchanger that adjusts the temperature of exhaust gas, and a reheater spray water heat amount that adjusts the temperature of the reheater.

  The power generation end efficiency calculation method according to the invention of claim 5 is a power generation end for calculating the power generation end efficiency of a thermal power plant that generates electricity by driving steam generated in a boiler to a turbine and driving a generator connected to the turbine. In the efficiency calculation method, the turbine chamber efficiency is obtained by dividing the amount of heat output from the turbine by the amount of heat input to the turbine, and the turbine chamber efficiency calculated by the boiler chamber efficiency calculation method according to claim 1 is calculated. The power generation end efficiency of the thermal power plant is calculated by multiplying the room efficiency.

  According to the first aspect of the present invention, when the boiler chamber efficiency is obtained by the loss method, the heat input to the turbine chamber side is positive as viewed from the turbine chamber side, and the heat output from the turbine chamber side to the boiler chamber side is Since the heat output from the turbine chamber side to the boiler chamber side is subtracted from the heat input to the boiler as the amount of boiler loss and the boiler chamber efficiency is calculated, it is equivalent to the boiler chamber efficiency calculated by the input / output heat method. Become. This makes it easy to compare with the boiler room efficiency calculated by the heat input / output method.

  According to the invention of claim 2, in the case of a gas-fired power plant, the reheater spray water heat amount for adjusting the temperature of the reheater supplied from the turbine chamber side is set as the loss amount of the boiler. The boiler room efficiency equivalent to the boiler room efficiency of the gas-fired power plant calculated by the law can be obtained.

  According to the invention of claim 3, in the case of an oil thermal power plant, the steam air preheater steam heat amount for preheating the air supplied from the turbine chamber side, the steam heat amount for heating the evaporator for heating the fuel oil, the fuel The boiler room efficiency is equivalent to the boiler room efficiency calculated by the heat input / output heat method of the oil-fired thermal power plant because the amount of heat of atomized steam spraying oil and the amount of heat of the reheater spray water adjusting the temperature of the reheater are used as the loss amount of the boiler. Efficiency can be obtained.

  According to the invention of claim 4, in the case of a coal-fired power plant, the soot blower steam heat supplied from the turbine chamber side, the steam heat amount for the gas gas heat exchanger for adjusting the temperature of the exhaust gas, and the temperature adjustment of the reheater are adjusted. Since the amount of reheater spray water to be used is the loss amount of the boiler, the boiler room efficiency equivalent to the boiler room efficiency calculated by the input / output heat method of the coal-fired power plant can be obtained.

  According to the invention of claim 5, since the power generation end efficiency is calculated by multiplying the boiler chamber efficiency calculated by the boiler chamber efficiency calculation method of claim 1 to claim 4 with the turbine chamber efficiency, Regardless of this, it is possible to evaluate the efficiency of the power generation end side by side.

Explanatory drawing of boiler heat output Qo (gas) in the case of applying the boiler room efficiency calculation method which concerns on embodiment of this invention to a gas thermal power plant. Explanatory drawing of boiler heat output Qo (oil) in the case of applying the boiler room efficiency calculation method which concerns on embodiment of this invention to a petroleum thermal power plant. FIG. 3 is an explanatory diagram of boiler heat output Qo (coal) when the boiler room efficiency calculation method according to the embodiment of the present invention is applied to a coal-fired power plant. Explanatory drawing of the waste gas calorie | heat amount of the exit of a preheater (AH). Explanatory drawing of the waste gas calorie | heat amount of the exit of a preheater (AH).

  Embodiments of the present invention will be described below. It is an object of the present invention to calculate and evaluate the power generation end efficiency ηp using the equation (1) regardless of whether the boiler room efficiency ηb1 based on the heat input / output method or the boiler efficiency ηb2 based on the loss method.

  For this reason, even when the power generation end efficiency ηp2 of the loss method is calculated by the equation (6), the same value as that obtained by the equation (5) of determining the power generation end efficiency ηp1 of the heat input / output method can be obtained. Thus, the method of calculating the boiler room efficiency ηb2 of the loss method will be reviewed.

  In the boiler room efficiency ηb1 of the heat input / output method, for example, the steam of the evaporator or the steam-type air preheater SAH is taken from the turbine bleed air, and is therefore drawn from the turbine heat input Qi. That is, in the calculation of the boiler room efficiency ηb1 of the heat input / output method, the turbine heat input Qi and the boiler heat output Qo are made equal. Accordingly, the power generation end efficiency ηp1 of the heat input / output method is expressed by the equation (10) when the equations (2) and (3) are substituted into the equation (5) and Qi = Qo.

ηp1 = Qm ÷ Qf (10)
On the other hand, in the boiler chamber efficiency ηb2 of the loss method, these turbine bleeds are handled as heat recovery to the boiler chamber side as shown in the equation (9), so that the boiler chamber efficiency ηb2 is increased. Therefore, when reviewing the method of calculating the boiler chamber efficiency ηb2 in the loss method, it is appropriate that the turbine extraction is not heat recovery but heat loss.

  Therefore, in the present invention, the heat input to the turbine chamber side as viewed from the turbine chamber side is positive, the heat output from the turbine chamber side to the boiler chamber side is negative, and the heat output from the turbine chamber side to the boiler chamber side is negative. Heat is subtracted from the heat input to the boiler as the amount of boiler loss, and the boiler room efficiency is calculated. This can be expressed as follows.

  The relationship between the boiler heat input Qf, the boiler heat output Qo, and the boiler loss Qr is expressed by equation (11).

Qo = Qf−Qr (11)
In addition, as described above, when the steam supply source of steam used in steam-using equipment such as a steam air preheater (SAH) is on the turbine chamber side, and the location where steam is used is on the boiler chamber side The boiler heat output Qo1 of the heat input / output method is expressed by equation (7), and the boiler heat output Qo1 is obtained by subtracting the SAH steam heat quantity Qsah from the boiler heat output Qo.

  The boiler room efficiency ηb1 in the heat input / output method is obtained by dividing the boiler heat output Qo by the boiler heat input Qf, as shown in equation (3). When the steam supply source of steam used in the steam air preheater (SAH) on the boiler chamber side is on the turbine chamber side, the SAH steam heat quantity Qsah is subtracted from the boiler heat output Qo to the boiler heat output Qo in (3). Substituting the boiler heat output Qo1 (= Qo−Qsah) and further substituting the equation (11), the equation (12) is obtained.

ηb1 ＝ Qo ÷ Qf
= (Qo−Qsah) ÷ Qf
= (Qf-Qr-Qsah) / Qf
= 1- (Qr + Qsah) / Qf (12)
Here, when comparing the equation (12) with the equation (4) showing the boiler chamber efficiency ηb2 of the loss method, it is appropriate to add the SAH steam calorie Qsah to the boiler loss Qr and not to recover heat but to use heat loss. It turns out that it is. In view of this situation, the loss calculation method for the loss of boiler room efficiency ηb2 is as follows. First, boiler output heat Qo (= turbine heat input Qi) for each fuel is determined as follows.

  When the thermal power plant is a gas thermal power plant, the boiler heat output Qo (gas) is determined as shown by equation (13).

Qo (gas) = (QMS + QHR-QCR-QFW) -Qrhs + Qmc (13)
QMS: main steam calorie, QHR: high temperature reheat steam calorie, QCR: low temperature reheat steam calorie, QFW: feed water calorie, Qrhs: reheater spray water calorie, Qmc: makeup water calorie FIG. It is explanatory drawing of the boiler heat output Qo (gas) in the case of applying the boiler room efficiency calculation method which concerns on a gas thermal power plant. The boiler 11 of the gas-fired power plant burns gas fuel in the furnace 12 to make the feed water flow rate FW from the feed water pump 13 into steam, and supplies it from the superheater (SH) 14 to the high-pressure turbine 15 as the main steam flow rate MS. The low-temperature reheat steam flow rate CR that has finished work in the high-pressure turbine 15 is supplied to the reheater (RH) 16 of the boiler 11 and is led to the intermediate-pressure turbine 17 as the high-temperature reheat steam flow rate HR. The steam that has finished is guided to the low-pressure turbine 18. The steam that has finished work in the low-pressure turbine 18 is returned to water by the condenser 19 and supplied to the boiler by the feed water pump 13. Note that a generator (not shown) is connected to the low-pressure turbine 18.

  Here, the amount of heat of the fuel is input to the boiler 11 as boiler input heat Qf, and the amount of heat obtained by subtracting the boiler loss Qr from the boiler input heat Qf becomes the boiler output heat Qo as shown in the equation (11). And ± of boiler output heat Qo (gas) is defined so that boiler output heat Qo (gas) may become equal to turbine input heat Qi. That is, when viewed from the turbine chamber side, heat input to the turbine chamber side is +, and heat output from the turbine chamber side to the boiler chamber side is −.

  First, since the main steam calorie QMS and the high-temperature re-steam calorie QHR are output from the boiler 11 to the turbine chamber side and become heat input to the turbine chamber side, as shown in the equation (13), the main steam calorie QMS The high-temperature re-steam heat quantity QHR is assumed to be +. Further, since the low temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are discharged from the turbine chamber side to the boiler room side, the low temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are set to − as shown in the equation (13). . Similarly, the reheater spray water heat quantity Qrhs is-because heat is output from the turbine chamber side to the boiler chamber side, and the make-up water heat quantity Qmc is + because heat is input to the turbine chamber side.

  The feed water flow rate FW basically uses the high pressure heater outlet feed water flow rate calculated based on the condensate flow rate standard. When the high-pressure heater outlet feed water flow rate is not calculated, the feed water flow rate measured at the economizer Eco inlet feed water orifice is used.

  The main steam flow rate MS is (feed water flow rate FW + reheater spray water flow rate rhs-boiler feed water pump turbine (BFP) high pressure drive steam amount), and the steam flow rate used in the boiler room (atomization, SAH, etc.) is Do not calculate. The SH spray water flow rate is added if the extraction point is before the feed water flow rate measurement point. On the other hand, if the extraction point is later, it is not calculated. For the high-pressure drive steam volume of BFP, only certain facilities are calculated. There are many places that are not in the latest firepower.

  The low temperature reheat steam flow rate CR is (main steam flow rate MS−high pressure heater drain flow rate by extraction from the high pressure turbine), and the amount of extraction from the high pressure turbine 15 is subtracted. If there is BFP low-pressure drive steam removal in this line, it is subtracted. The high-temperature reheat steam flow rate HR is (low-temperature reheat steam flow rate CR + RH spray water flow rate rhs).

  Next, when the thermal power plant is an oil thermal power plant, the boiler heat output Qo (oil) is determined as shown by the equation (14).

Qo (oil) = (QMS + QHR-QCR-QFW)-Qsah-Qev-Qba
-Qrhs + Qsahd + Qevd + Qmc (14)
QMS: Main steam calorie, QHR: High temperature reheat steam calorie, QCR: Low temperature reheat steam calorie, QFW: Feed water calorie, Qsah: SAH steam calorie, Qev: Steam calorie for heating evaporator, Qba: Atomized steam calorie, Qrhs : Reheater spray water calorie, Qsahd: SAH drain calorie, Qevd: Evaporator drain calorie, Qmc: Supply water calorie Figure 2 shows the boiler room efficiency calculation method according to the embodiment of the present invention applied to a petroleum thermal power plant It is explanatory drawing of the boiler heat output Qo (oil) in the case of carrying out. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In the case of oil-fired power plants, in addition to gas-fired power plants, SAH steam heat quantity Qsah supplied to a steam air preheater (SAH), and evaporator heating supplied to a evaporator that heats fuel oil Steam heat quantity Qev and atomized steam heat quantity Qba for adding oil to the oil burner to atomize the oil are added. Along with this, the SAH drain heat quantity Qsahd and the evaporator drain heat quantity Qevd are generated.

  First, since the main steam calorie QMS and the high-temperature re-steam calorie QHR are output from the boiler 11 to the turbine chamber side and become heat input to the turbine chamber side, as shown in the equation (14), the main steam calorie QMS The high-temperature re-steam heat quantity QHR is assumed to be +. Further, since the low-temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are discharged from the turbine chamber side to the boiler room side, the low-temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are set to − as shown in the equation (14). .

  Further, since the atomized steam calorie Qba, SAH steam calorie Qsah, evaporator heating steam calorie Qev, and reheater spray water calorie Qrhs are output from the turbine chamber side to the boiler chamber side, as shown in equation (14) It is assumed that the SAH drain calorie Qsahd, the evaporator drain calorie Qevd, and the makeup water calorie Qmc are + because they are input to the turbine chamber side.

  Next, when the thermal power plant is a coal thermal power plant, the boiler heat output Qo (coal) is determined as shown by the equation (15).

Qo (Coal) = (QMS + QHR-QCR-QFW)-Qsb-Qggh
-Qrhs + Qgghd + Qmc (15)
QMS: Main steam heat, QHR: High temperature reheat steam heat, QCR: Low temperature reheat steam heat, QFW: Feed water heat, Qsb: Sootblower steam heat, Qggh: Steam heat for GGH, Qrhs: Reheater spray water heat, Qgghd: GGH drain heat quantity, Qmc: makeup water heat quantity FIG. 3 is an explanatory diagram of boiler output heat Qo (coal) when the boiler room efficiency calculation method according to the embodiment of the present invention is applied to a coal-fired power plant. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In the case of a coal-fired power plant, in addition to the case of a gas-fired power plant, a soot blower steam heat quantity Qsb for blowing off coal ash, a gas gas heat exchanger (for adjusting the temperature of the electric dust collector EP of the coal flue equipment) GGH) steam heat quantity Qggh is added. Along with this, a GGH drain heat quantity Qgghd is generated.

  First, since the main steam calorie QMS and the high-temperature re-steam calorie QHR are output from the boiler 11 to the turbine chamber side and become heat input to the turbine chamber side, as shown in the equation (15), the main steam calorie QMS The high-temperature re-steam heat quantity QHR is assumed to be +. Further, since the low-temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are discharged from the turbine chamber side to the boiler room side, the low-temperature reheat steam heat quantity QCR and the feed water heat quantity QFW are set to − as shown in the equation (15). .

  Further, since the soot blower steam calorie Qsb, the GGH steam calorie Qggh, and the reheater spray water calorie Qrhs are output from the turbine chamber side to the boiler chamber side, it is-as shown in the equation (15), and the GGH drain heat amount Qgghd and makeup water heat quantity Qmc are set to + because they are input to the turbine chamber side.

  Next, heat output from the turbine chamber side to the boiler chamber side, heat input to the turbine chamber side other than the main steam heat quantity QMS and the high temperature re-steam heat quantity QHR will be described. For heat output from the turbine chamber side to the boiler chamber side, SAH steam calorie Qsah, steamer heating steam Qev, atomized steam calorie Qba, sootblower steam calorie Qsb, GGH steam calorie Qggh, reheater spray Hydrothermal quantity Qrhs etc. Further, heat input to the turbine chamber other than the main steam calorie QMS and the high-temperature re-steam calorie QHR includes make-up water calorie Qmc, GGH drain calorie Qgghd, SAH drain calorie Qsahd, evaporator drain calorie Qevd, and the like.

(1) SAH steam calorie Qsah
Conventionally, when SAH steam is supplied from the turbine chamber to the boiler chamber, “SAH steam heat amount−SAH drain heat amount” is considered as heat input to the boiler chamber, but the present invention changes this idea.

  Considering the actual exhaust heat of the boiler, the air preheated by the steam air preheater (SAH) is finally exhausted and discharged outside the boiler system. The exhaust gas at the outlet of the preheater (AH) has a certain amount of heat, and the amount of heat becomes a loss of the boiler.

  FIG. 4 is an explanatory diagram of the amount of exhaust gas heat at the outlet of the preheater (AH). As shown in FIG. 4, the amount of exhaust gas heat at the outlet of the preheater (AH) is not only the amount of combustion heat due to the combustion of fuel, but also the amount of heat received by a forced air blower (FDF) that sends air to the boiler, a steam air preheater This includes the preheating amount of air by (SAH) and the preheating amount of fuel by the evaporator.

  Conventionally, the efficiency of the boiler itself was separated from the turbine chamber side, so the amount of air preheated by the steam air preheater (SAH) and the amount of fuel preheated by the evaporator were externally input (heat received). However, for the reason described above, the present invention considers it as a loss.

  The steam loss of the steam air preheater (SAH) corresponds to the “preheating amount of air by SAH” portion of FIG. And in the calculation of the boiler room efficiency ηb2 of the loss method, the amount of exhaust gas heat discharged from the AH outlet is calculated as various losses. That is, it is calculated as dry exhaust gas loss L1, loss L2 due to hydrogen in fuel, loss L3 due to moisture in fuel, moisture loss L4 in air, and air preheater leakage loss L5.

  As can be seen from FIG. 4, since the SAH vapor loss is already included in the losses from L1 to L5, newly calculating and accounting for the loss results in double counting of the loss. Therefore, the boiler room efficiency ηb2 of the loss method is considered not to be included in the loss. In addition, since the heat reception of the air by the forced air blower FDF is an event that occurs regardless of the turbine chamber, it is treated as “heat reception” as usual.

(2) Steam calorie Qev for heating the evaporator
The same idea as SAH steam can be applied to the loss of evaporator steam. Like SAH, it is used when the loss due to the evaporator is individually evaluated, otherwise it is considered to be included in the losses L1 to L5. The steam loss due to the evaporator is included in the boiler room efficiency ηb2 of the loss method do not do.

(3) Atomized steam calorie Qba
The loss due to the atomized steam is considered to be “the amount of heat generated when the atomized steam is thrown out of the boiler”. FIG. 5 is an explanatory diagram of the amount of heat of the atomized steam. As shown in FIG. 5, the amount of heat that makes the makeup water atomized steam is the loss L9 (1), and is expressed by the equation (16).

L9 (1) (%) = (N ÷ F × Hn) ÷ Hh (16)
N: Atomized steam volume (kg / h), F: Fuel flow rate (kg / h), Hn: Fuel heat value (kJ / kg), Hh: Atomized steam enthalpy (kJ / kg)
Further, the heat recovery amount L9 (2) of the atomized steam is the amount of atomized steam heat discarded to the outside of the boiler, and is expressed by the equation (17).

L9 (2) (%) = (N ÷ F × cw × Hn) ÷ Tg (17)
cw: specific heat of steam (kJ / kgK), Tg: exhaust gas temperature at outlet of AH Here, the atomized steam temperature in the 350MW class boiler is about 200 ° C, and the exhaust gas temperature at AH outlet is about 140 ° C. The heat difference (recovered part) is recovered, and the total atomized steam loss is “loss L9 (1) −recovered part L9 (2)”. Note that the amount of recovered heat is very small with respect to the amount of heat lost, and therefore need not be considered.

(4) Sootblower steam calorie Qsb
The sootblower steam is the same as the atomized steam.

(5) Steam heat quantity for GGH Qggh
The amount of steam heat used in the gas gas heat exchanger (GGH) is not the amount of heat that directly affects the boiler chamber efficiency. However, in the concept of the present invention, the loss chamber efficiency ηb2 is used regardless of whether the steam supply source is a boiler or a turbine. Calculate as loss.

(6) Reheater spray water heat quantity Qrhs
The reheater spray is heat output from the turbine chamber, and an increase in flow rate results in a decrease in heat input to the turbine chamber. Since it is considered that the turbine chamber heat input and the boiler chamber heat input are equal, they are counted as -Qrhs in the boiler heat output, and are also counted as "loss" in the boiler room efficiency ηb2 of the loss method.

(7) Supply water calorie Qmc
The makeup water is heat input to the turbine chamber, and an increase in the flow rate increases heat input to the turbine chamber. Since it is considered that the turbine chamber heat input and the boiler chamber heat input are equal, they are counted as + Qmc in the boiler heat output, and are also counted as “recovery” in the loss method boiler room efficiency ηb2.

(8) GGH drain heat Qgghd, SAH drain heat Qsahd, evaporator drain heat Qevd
The heat amounts of the SAH drain, the evaporator drain, and the GGH drain are the heat input of the turbine chamber, and the heat amount is counted as the boiler heat output, and is also counted as “recovery” even in the boiler chamber efficiency ηb2 of the loss method.

  Next, the above-mentioned contents are summarized, and the final calculation formula for the “loss method boiler room efficiency ηb2” for each fuel is shown. Loss method boiler room efficiency ηb2 in the case of gas-fired power plant is given by equation (18), loss method boiler room efficiency ηb2 in case of oil-fired power plant is given by equation (19), and loss in the case of coal-fired power plant. The boiler room efficiency ηb2 of the method is shown in equation (20).

(A) Gas-fired power plant ηb2 = 100− (L1 + L2 + L3 + L4 + L5 + L6 + L7 + L8
-L16 + L18-L19) (18)
(B) Oil-fired power plant ηb2 = 100− (L1 + L2 + L3 + L4 + L5 + L6 + L7 + L8
+ L9 + L11 + L12-L16 + L18-L19) (19)
(C) Coal-fired power plant ηb2 = 100− (L1 + L2 + L3 + L4 + L5 + L6 + L7 + L8 + L10 + L13
+ L14 + L15-L16-L17 + L18-L19 + L20) (20)
L1: Dry exhaust gas loss, L2: Fuel hydrogen loss, L3: Fuel moisture loss, L4: Air moisture loss, L5: Air preheater leakage loss, L6: CO loss, L7: Radiation / heat transfer loss, L8: Pipe loss, L9: Atomized steam loss, L10: GGH steam loss, L11: SAH steam loss, L12: Evaporator steam loss, L13: Unburned ash loss, L14: Fly ash sensible heat loss, L15: Clinker hopper radiant heat loss, L16: FDF power recovery, L17: PAF power recovery, L18: RH spray water loss, L19: Makeup water calorie recovery, L20: Soot blower steam loss In addition, since the heat input to the turbine chamber side when viewed from the turbine chamber side is positive and the heat output from the turbine chamber side to the boiler chamber side is negative, the boiler chamber efficiency is calculated. Equivalent to efficiency. This makes it easy to compare with the boiler room efficiency calculated by the heat input / output method. Further, the power generation end efficiency ηp can be calculated and evaluated using the equation (1) regardless of whether the boiler room efficiency ηb1 by the heat input / output method or the boiler efficiency ηb2 by the loss method.

DESCRIPTION OF SYMBOLS 11 ... Boiler, 12 ... Furnace, 13 ... Feed water pump, 14 ... Superheater, 15 ... High pressure turbine, 16 ... Reheater, 17 ... Medium pressure turbine, 18 ... Low pressure turbine, 19 ... Condenser

Claims (5)

  According to the loss method, which calculates boiler room efficiency by subtracting the amount of heat loss from the amount of heat input to the boiler of a thermal power plant that introduces steam generated in the boiler to the turbine and drives the generator connected to the turbine to generate power In the boiler chamber efficiency calculation method, the heat input to the turbine chamber side as viewed from the turbine chamber side is positive, the heat output from the turbine chamber side to the boiler chamber side is negative, and the boiler from the turbine chamber side is The boiler room efficiency calculation method, wherein the boiler room efficiency is calculated by subtracting the heat output to the room side from the heat input to the boiler as a loss amount of the boiler.   When the thermal power plant is a gas thermal power plant, the amount of heat supplied from the turbine chamber side as the loss amount of the boiler is a reheater spray water heat amount for adjusting the temperature of the reheater. The boiler room efficiency calculation method according to claim 1, wherein the boiler room efficiency is calculated.   When the thermal power plant is an oil thermal power plant, the amount of heat supplied from the turbine chamber side, which is the loss amount of the boiler, is the steam air preheater steam heat amount that preheats the air, the vaporization that warms the fuel oil The boiler chamber efficiency calculation method according to claim 1, wherein the steam chamber heating heat amount, the atomizing steam heat amount for spraying fuel oil, and the reheater spray water heat amount for adjusting the temperature of the reheater are used.   When the thermal power plant is a coal thermal power plant, the amount of heat supplied from the turbine chamber side as the loss amount of the boiler is a soot blower steam heat amount, a steam heat amount for a gas gas heat exchanger that adjusts the temperature of exhaust gas, The boiler room efficiency calculation method according to claim 1, wherein the amount of heat of the reheater spray water for adjusting the temperature of the reheater is used.   In a power generation end efficiency calculation method for calculating power generation end efficiency of a thermal power plant that introduces steam generated in a boiler into a turbine and drives a generator connected to the turbine to generate power, the amount of heat output from the turbine is calculated The turbine chamber efficiency is obtained by dividing by the amount of heat input to the boiler, and the turbine chamber efficiency calculated by the boiler chamber efficiency calculation method according to claim 1 to 4 is multiplied by the turbine chamber efficiency to obtain the power generation end efficiency of the thermal power plant. A power generation end efficiency calculation method characterized by calculating

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