JPS604703A - Diagnostic device for performance of feedwater heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention diagnoses the performance of a feedwater heater used in a thermal cycle plant such as a thermal power plant, and diagnoses the performance of the feedwater heater to enable its economical operation. Related to diagnostic equipment.

[Technical application of the invention and its problems] In thermal cycle plants such as thermal power plants and nuclear power plants, feed water heaters are used to heat condensate water that is fed to the boiler.

Figure 1 shows the schematic configuration of a thermal power plant. Steam generated in a boiler 1 passes through a main steam pipe 2 and enters a high-pressure turbine 3. After doing work there, it is passed through a low-temperature reheat steam pipe 4. The steam is then introduced into a reheater 5, where it is reheated, passes through a reheat steam pipe 6, enters an intermediate pressure turbine 7, performs work there, and then passes through a crossover pipe 8, enters a low pressure turbine 9, where work is performed. do.

The C loss 7j thermal energy due to these works is converted into electrical energy by power generation 110 driven by each turbine. The steam that has completed its work in the low-pressure turbine 9 is introduced as exhaust into the condenser 11, where it is cooled with cooling water such as seawater and becomes condensed water.

This condensate is pressurized by the condensate pump 12, heated by the low-pressure feed water heaters 13a, 13b, and 13C, and degassed.
After being heated and deaerated, the pressure is increased by the boiler feed water pump 15, heated again by the high pressure feed water heater 16a116b116C, and water is supplied to the boiler 1 through the water feed pipe 17. The low-pressure feedwater heaters 138 to 13C1, the deaerator 14, and the high-pressure feedwater heaters 168 to 16C are heated by extraction air from the turbine 3.7.9, and the boiler feedwater pump steam turbine 18 that drives the boiler feedwater pump 15 is Medium pressure turbine 7
Powered by bleed air.

In thermal power plants configured as described above, monitoring of plant performance has conventionally focused on the generating end or sending end efficiency of the unit, mainly boiler and turbine performance, and for auxiliary equipment, the operating status values of the equipment have been Since the main focus of monitoring was to keep within the limit values, wJ carrier equipment performance deteriorated J3
There was no detailed monitoring of the demand and its trends. That is, for example, high pressure and low pressure feed water heater 13a
The performance of ~13c and 16a~16c was merely monitored based on the difference in temperature at the water supply outlet terminal and the temperature at the drain outlet.

However, in recent years, thermal power plants have been using carbon steel for the heating pipes of high-pressure feed water heaters due to the high pressure and high temperature steam conditions and the associated problems with water supply treatment. Oxygen, iron, PH, etc. meet water supply treatment standard values (
In negative flow unit 1-, boiler oxygen near ppb or less, iron: 1011+] tl or less, PH: 9.3 to 9.5
), and it has become necessary to control the iron oxide scale, which is mainly composed of corrosion products such as Fe 304 , in the heating tubes of high-pressure feed water heaters, to be kept to a minimum.

In addition, high-pressure feed water heaters are susceptible to erosion (inlet attack) at the end of the heating tube due to the vortex generated in the water chamber.
It is installed inside the water chamber.

By the way, recently, iron oxide scale has been deposited on the water supply side of the high-pressure feed water heater, that is, inside the heating pipes and in the rectification direction mentioned above, causing an increase in the differential pressure between the water supply inlet and outlet, and as a result, the temperature of the ice compartment partition plate of the feed water heater has increased. This has caused problems such as damage, increased load on boiler feed pumps, the associated maximum working pressure of water pipes being exceeded, and a decrease in power plant efficiency. In particular, in the case of Scale Iq@, clogging in the rectifying cylinder is more prevalent than in the heating tube, and the rectifying direction accounts for most of the differential pressure of the water supply. In this case, since there is no reduction in the heat exchange rate inside the heating tube, this does not appear as a change in the temperature difference at the water supply outlet terminal or the drain outlet temperature difference.

However, no matter what part of the feedwater heater the scale is attached to, the increase in external pressure will increase the load on the boiler feedwater pump and actually increase the power plant loss.
If the loss per minute of the boiler feedwater pump is not evaluated at the same time, the deterioration of the feedwater heater cannot be accurately evaluated.

[Object of the Invention] The present invention has been made in order to eliminate the drawbacks of the prior art as described above. The object of the present invention is to provide a performance diagnostic device for a feed water heater that accurately diagnoses the performance of a C1 feed water heater and enables economical operation of a thermal cycle plant.

[Summary of the Invention] Performance diagnostic device for a feed water heater of the present invention (U) Feed water inlet temperature of the feed water heater detected by a detector [1, feed water outlet temperature t2, drain outlet temperature td, internal pressure P, Preset planned terminal angle difference TD.

and the planned drain outlet temperature difference are calculated by a calculator to output the terminal temperature difference change △TD and the drain outlet temperature difference change △DC, and the feed water inlet pressure P+ of the feed water heater and the feed water outlet pressure detected by the detector are P2 calculates and outputs the water supply pressure loss difference △P, and uses these 'fJ calculation output type input data to calculate the heat consumption rate reduction suitability 31△l-I
Calculate R and calculate and output the loss F due to the decrease in heat consumption rate,
This loss cost F and the feed water heater countermeasure cost Fc are compared using a comparator, and the feed water pressure loss difference △I and the preset allowable pressure loss △] are compared, and based on these comparison results, The device is configured to operate the determiner when

[Embodiments of the Invention] Below, the principle, embodiments, and operation of the present invention will be explained with reference to FIGS. 2 to 7.

Figure 2 shows symbols representing the pressure and temperature around the high-pressure feed water heater 16C in Figure 1. The water supply inlet pressure and temperature are P + , L + , and the water supply outlet pressure and temperature are P2. , [2. If the internal pressure and internal saturation temperature of the feed water heater 160 are p and ts, and the drain outlet temperature \~-7 is td, each part (a), (b), (c), (d)
Under normal conditions, the temperature state is distributed as shown by the solid line in FIG. 3, but when performance deterioration occurs in the heater, the temperature changes as shown by the chain line in FIG. 3.

That is, when performance deterioration occurs in the heater, the water supply outlet temperature t2 decreases by TDo - TD (), and the drain outlet temperature t2 decreases by TDo - TD.
d increases by Dc-DCo.

On the other hand, when the pressure loss at the inlet and outlet of the feedwater heater 16c is normal, the boiler feedwater pump 15 driven by the boiler water pump steam turbine 18 is composed of the losses shown in FIG. , is operated along the resistance curve A during normal operation in the figure. Here, suppose that △h(
kg/clIl), the resistance curve rises by Δh as shown in resistance curve B when pressure loss increases in FIG.

That is, Δ1) directly appears as an increase in the discharge pressure of the boiler feed water pump.

The heat consumption rate deviation due to the water supply outlet 1 terminal temperature difference TD1 drain outlet temperature difference DC and the boiler feed water pump discharge pressure change ΔP is as shown in FIGS. 5 and 6.

The present invention calculates terminal temperature difference change △TD' (=TDo -TD), drain outlet temperature difference change △DC (=DCo -Dc) and supply water pressure loss difference △P (=P+ - P2) based on various input data. Therefore, the basic principle is to calculate heat consumption rate deviation compensation by calculating these together with other input data, and to determine whether to stop the unit, continue operation, or take measures based on these results.

FIG. 7 shows an embodiment of the performance diagnostic device for a feed water heater according to the present invention. In the same figure, the feed water inlet temperature of the feed water heater 7j, which is detected by the detectors 20 to 23, the feed water outlet temperature [2, the drain outlet temperature td, and the internal pressure P] are the preset planned termiple wetness difference 1. - D o and the planned drain outlet temperature difference DCo are input to the TD and DC change calculation unit 24, and by calculating the following formulas, △TD, △
Output DC.

Inner saturation temperature: ts=f(P)...(1) Actual terminal temperature difference; l-[)=ts-t2...(2)
Terminal altitude difference change: △TD=TDo-TD...(3) Actual drain outlet temperature difference; DC=td-t+...................................(4) Drain outlet temperature difference change: 4 ΔDC=DCo-Dc (5) In addition, the feed water inlet pressure P1 and the feed water outlet pressure P2 of the feed water heater detected by the detectors 25 and 26 are calculated by the feed water pressure loss change calculation device 27. is input, and the water supply pressure loss difference △
P is calculated by the following formula % formula % (6).

This calculation result △P is the preset allowable pressure loss △Po
, and the maximum working pressure Po are input to the comparator 28 for comparison calculation.

The comparator 28 outputs ΔP to the heat consumption rate change calculation device 29 when the following formula % formula % (7) is satisfied, and outputs ΔP to the unit stop determination device 30 when the formula (7) is not satisfied. Emit output.

On the other hand, the power plant efficiency calculation device 31 calculates the turbine room heat consumption rate 1
−I R, boiler efficiency ηB, starting engine power N, heat consumption rate deviation KTD, KOC, which depends on TD, DC, ΔP shown in Figs. 5 and 6, and △P [%]. The temperature is outputted to the consumption rate change foot calculating device 29 in degrees Celsius.

This extraction device 29 listens to the input signals from the above-mentioned sieving device 24.31 and comparator 28 according to the following equation, and calculates the heat consumption rate reduction amount △HRT o , △)-1Ro c, △l-I
Output R△p[Kcal/kwh].

△1-IRvo=HRX (1+KTD/100)...
・・・・・・・・・(8) △HRoc=zRx (1+Koc/100
)・・・・・・・・・〈9) △HR△p=HRx(△p to 1+/100)・・・・
(10) The heat soaking 8 rate loss device 32 calculates the input signal from the calculation device 29 according to the following equation, and outputs a conversion F based on the reduction in heat consumption rate.

△1-IR-△HRvo+△HRoc+△1-IR△
p・・・・・・(11) F=ΔHRXNXUXV/77e−・・・(12)
However, U: Operating time [hrs] V: Fuel vehicle lll1l [yen/Kcal] This performance result F
is led to the comparator 34 together with the output FC of the feed water heater vs.
The output is optically transmitted to 5a3 and the countermeasure required determination unit 36.

When the signal from the comparator 34 is F<[c, the determiner 35 notifies the continuation of operation, and the determiner 36 notifies the signal from the comparator 34 if F>FC and that countermeasures are required. . Naa
The high-pressure feed water heaters in recent thermal power generation facilities are usually equipped with two lines and a 25% or 50% capacity feed water bypass, so if countermeasures are required, (a) Measures can be taken one series at a time without any restrictions.

(b) Countermeasures for load reduction.

(c) Extended until regular inspection.

It is desirable to output the results including the diagnosis results. Further, when the determiner 30 receives the signal from the comparator 28, it notifies that the unit should be stopped immediately and countermeasures should be taken to prevent danger.

This allows operators to decide whether to immediately stop the unit and take countermeasures, to continue operation, or to take countermeasures while continuing operation, taking into consideration the economic efficiency of the plant. can be determined accurately.

In addition, in the present invention, it is not necessarily necessary for each arithmetic unit or decision device to be independent as shown in FIG. It is also possible to realize Noh.

[Effects of the Invention] As explained above, according to the device of the present invention, it is possible to determine whether or not there is an abnormality in the operating limit value from the operating state value of the feed water heater, and to take economical measures against changes in performance within the operating limit value. zu°
By doing so, the thermal cycle plant can be operated systematically and efficiently.

[Brief explanation of drawings]

Figure 1 is a piping system diagram illustrating a thermal power plant;
The figure is an explanatory diagram of temperature and pressure symbols around the feed water heater,
FIG. 3 is a characteristic diagram showing the temperature distribution of the feed water heater, FIG. 4 is a characteristic diagram of a turbine-driven boiler feed water pump, and FIGS. 5 and 6 are graphs each showing heat consumption rate deviation curves.
FIG. 7 is a block diagram showing one embodiment of the device of the present invention. 1...Boiler 2...Main steam pipe 3...High pressure turbine 4...・
......Low temperature reheat steam pipe 5...
...Reheater 6...Reheat steam pipe 7...
・・・・・・Intermediate pressure turbine 8・・・・・・・・・・・・
Crossover pipe 9・・・・・・・・・・・・Low pressure turbine 10・・・・・・・・・・Generator 11・・・・・・・・・・・・Condenser 12・・・・・・・・・Condensate pump 13a~13
C...Low pressure feed water heater 14...Deaerator 15...Boiler feed water pump 168
~16G... High-pressure feed water heater 17... Water supply pipe 18... ij<Steam turbine for Villa feed water pump 20-23.25 .26...Patent attorney representing the detector Satoshi Suyama - Figure 1 @ 2 Figure 3 Figure 4 Figure 5 Figure 6 Shi1 Figure 7

Claims (1)

[Claims] (1) Input the feed water inlet temperature, feed water outlet temperature, °13 drain outlet temperature, and internal pressure of the feed water heater detected by the detector and set the S1 screen terminal temperature difference and planned drain outlet temperature in advance. A TO-DCC change wave calculating device that calculates and outputs a terminal temperature difference change (15) and a drain outlet temperature difference change based on the opposite difference; A feed water pressure loss change calculation device that inputs the feed water outlet pressure, turns off and outputs the feed water pressure loss difference, an output from the TD-DC change maximum calculation device, and an output from the feed water pressure loss change calculation device. , and a heat consumption rate loss calculation device that calculates the total amount of reduction in heat consumption rate based on various input data indicating power plant efficiency, calculates the loss cost due to the reduction in heat consumption rate, and outputs this, and this heat consumption rate. When the loss cost calculated by the loss calculation device is compared with the feed water heater countermeasure cost, the water supply pressure loss difference and the preset allowable pressure loss are compared, and the judgment device is activated based on the results of these comparisons. A performance diagnostic device for a feed water heater, comprising a comparator for determining the performance of a feed water heater.