JPS6257633A - Device for monitoring and controlling waste gas - Google Patents

Abstract

PURPOSE:To efficiently remove sulfuric acid in an electric power plant by obtaining a corrosion rate coefficient from the SO3 concn. and water content in waste gas and the temp. of the device medium, further calculating the desired medium temp. from the coefficient so that the removal rate of sulfuric acid is maximized, and controlling a valve of a water cooler. CONSTITUTION:The waste gas temp., the water content in the waste gas and the temp. of the medium for a gas-gas heat exchanger are inputted to a waste gas monitor and control unit 9 from points (a), (b) and (c), the SO3 concn. in the waste gas is obtained from the waste gas temp., the dew point of sulfuric acid is obtained from the SO3 concn. and the water content and a corrosion rate coefficient is obtained from the dew point of sulfuric acid and the medium temp. The coefficient is inputted to an arithmetic controller for waste gas removal, the obtained desired medium temp. is compared with the medium temp., the opening degree of the valve of a water cooler 8 is calculated from the difference between the temps. and the valve is controlled. Consequently, sulfuric acid can be removed at a high rate, the treatng equipment can be on-line monitored and hence an accident in the plant can be rapidly coped with.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an exhaust gas monitoring f81J control device for a power plant that predicts and controls the removal of sulfuric acid from the degree of corrosion of equipment for desulfurizing exhaust gas in a thermal power plant or the like. .

[Background of the invention]

In a power generation plant, exhaust gas emitted from a boiler passes through exhaust gas treatment equipment and is released into the atmosphere. This exhaust gas contains Sob, and the 80° concentration corrodes the gas-gas heat exchanger. In addition, monitoring this with online measuring instruments, etc. is recommended, for example, in the magazine [Thermal and Nuclear Power Generation J.
VOL, No. 28 No. 250, etc., the degree of corrosion is determined from this exhaust gas, and the removal of sulfuric acid is determined from the amount of corrosion for control purposes.
There was no example of online control using an ff calculator. In addition, regarding the degree of wear due to corrosion of gas-gas heat exchangers, there is no example of the most efficient method of removing sulfuric acid from exhaust gas.

Incidentally, a related known example is JP-A No. 56-59313.

[Purpose of the invention]

The purpose of the present invention is to monitor the extent to which the plant is corroded by S03 contained in the exhaust gas generated in the power plant, obtain the removal rate of desulfurization from this degree of corrosion, and obtain the removal rate from the predetermined removal rate. An object of the present invention is to provide a control device for removing sulfuric acid from exhaust gas while monitoring corrosion using an exhaust gas monitoring control device.

[Summary of the invention]

The main point of the present invention is to incorporate an exhaust gas removal arithmetic control device and a medium temperature output control device into the conventional corrosion monitoring system f1t, calculate the corrosion degree coefficient a based on data from the plant, and then calculate the exhaust gas Find the removal rate of , and from this removal rate set the target medium temperature p[
The purpose of this invention is to control the pulp of the water cooler by performing the following calculations. Furthermore, information regarding exhaust gas removal is outputted to the output device d, and the exhaust gas is also monitored.

[Embodiments of the invention]

Figure 'g1 is a block diagram showing a typical configuration of the present invention. To simplify the explanation, a case is shown in which the exhaust flue of the exhaust gas treatment equipment of the power generation plant is a one-way pipe.

Fuel is combusted within the boiler 1 and exhaust gas is generated.

The exhaust gas is transferred to an electrostatic precipitator 2, a gas-gas heat exchanger 3,
The desulfurization device 4 is malted, passes through the steam heater 5, the gas-gas heat exchanger 53, and the steam heater 6 again, and is discharged into the atmosphere from the chimney 7.

Since the release of this exhaust gas is undesirable, it is necessary to monitor the exhaust gas and control its removal.

To monitor the exhaust gas, plant data such as the exhaust gas temperature T, the moisture H20 in the exhaust gas, and the gas-gas heat exchanger medium temperature Taas are required, and these are shown in a of FIG.

It is taken into the exhaust gas monitoring and control device 1o from points b and a.

The exhaust gas monitoring and control device 110 performs necessary arithmetic processing based on the plant data and outputs the results to the output device δ10, so that data necessary for exhaust gas monitoring can be referenced in a timely and targeted manner.

In addition, in order to perform exhaust gas removal control, data for controlling the cold water from the water cooler 8 is created after performing necessary arithmetic processing based on the corrosion coefficient obtained in the exhaust gas monitoring and control device flO. This is possible by outputting to the gas-gas heat exchanger 3.

Next, details of the gas-gas heat exchanger 3 will be explained.

FIG. 2 is a detailed view of the gas-to-gas heat exchanger 63 of FIG.

The exhaust gas flowing from the electrostatic precipitator 2 enters the heat absorption unit 11, flows between the frames 1 to 8, and flows from the heat absorption unit 11 to the desulfurization unit 4.

The desulfurized exhaust gas flowing from the steam heater 5 enters the heat recovery 12, passes between the frames 1 to 8 while being heated, and flows to the steam heater 6. Furthermore, the pipe from the water cooler 8 is wrapped around the medium 14 connecting between the frames 13 and 13', and by opening and closing the cold water valve 15,
Cool the N body 14. However, in order to perform removal monitoring control, the temperature of the medium is measured by attaching it to the medium 14 of the heat absorber 11.

FIG. 3 is a detailed diagram of the exhaust gas monitoring and control device 9 shown in FIG.

In Fig. 3, the plant data separated from points a, b, and a enters the process input device 16, undergoes necessary conversion, and then is sent to the 505m degree calculation device 17, which calculates the temperature at the dielectric point. It is input to the device 18, the corrosion coefficient calculation device 19, the exhaust gas removal S control device, controls the exhaust gas removal rate and the medium temperature, and outputs the medium current +3゜ output to the point g in the control device 21. be done. Okay, each calculation device 17, 18, 19, 2
The calculation result of 0 is output to the output control device [21, and the output control device 21 outputs it to the output device 10.

In the Sob laterality calculation device 17, the memory circuit 23
The relationship between exhaust gas temperature T and Son chronicity SOs' is stored in , and this relationship is as follows: SOs'=f(T') ・・・・・・・・・(
1) Based on the relationship of equation (1), [, exhaust gas temperature T from point a
From the data, SOn concentration, SO,=f(T) ・・・・・・・・・(2)
is stored in the output control device jt21 and the exhaust gas removal calculation control device.

The sulfuric acid dew point temperature calculation device 18 stores in advance in the memory circuit 24 the relationship between the moisture H30' in the exhaust gas and the corrected temperature α', α''''' (H, o') .
...(3), and based on the relationship of equation (3), calculate the corrected temperature α from the moisture H10 data in the exhaust gas from point b,
α'=f(H2O) ・−・・・・・・・(
4) and further stores this in the output control device 21.

Based on the SO and concentration SOx calculated by equation (2) and the correction temperature α calculated by equation (4), the sulfuric acid dew point temperature Ta is calculated as Ta
=f (SOs−α) ・・・・・・・・・(5)
It is calculated by Further, this sulfuric acid dew point temperature T is stored in the output control device 21.

In the corrosion coefficient calculation control device 19, the relationship between the sulfuric acid dew point temperature Ta', the medium temperature Toam' of the gas-gas heat exchanger 3, and the corrosion coefficient δ' is stored in advance in the memory circuit 25, and this relationship is , δ'=f(Ta', Tacs') -=...(6
) Based on this relationship, the corrosion coefficient δ is calculated using the equation (7) from the sulfuric acid dew point temperature T4 calculated using the equation (5) and the medium temperature T aas data from point C of the plant. 21.

δ''' (Ta, TGas) ・・・・・・
...(7) Also, the corrosion coefficient δ calculated by equation (7)
is input to the exhaust gas removal arithmetic and control device 20 in order to monitor and control exhaust gas removal.

In the medium temperature output control device 22, the target medium temperature T obtained by the exhaust gas removal calculation control device 20 is inputted, and the C of the plant is inputted.
A comparison calculation is performed with the medium temperature T oam taken from the point to determine the temperature difference ΔT. The temperature difference ΔT is ΔT=T, -TGas ・・・・・・・・・(
8) Calculate the opening degree O of the cold water valve device 15 from the temperature difference ΔT obtained by equation (8), and output it as a control amount to the cold water valve device 15. The relationship between this temperature difference ΔT and the opening degree O of the chilled water pulp machine 15 is as follows: 0=f(ΔT) (9) FIG. 4 shows the exhaust gas removal monitoring and control device 20 in FIG. 3. FIG.

In FIG. 4, after the corrosion coefficient δ obtained by the corrosion coefficient calculation control device 19 is inputted to the sulfuric acid removal rate calculation device 26 and the target medium temperature calculation device 28, it is input to the medium 14 of the gas heat exchanger 3. The target medium temperature T0 for the target medium temperature T0 is determined and output to the medium temperature output control device 22 and the output control device i#21. 29 is a memory circuit.

In the sulfuric acid removal rate calculation bag jf26, the memory circuit 2
7 should store the relationship between the corrosion coefficient δ', the 80m concentration SO1', and the sulfuric acid removal rate θ'.

θ'=f(δ', So,') ・・・・・・・・・
・(10) Based on the relationship of this formula (10), the removal rate θ for sulfur is determined from the already determined Sow concentration SOs and corrosion degree coefficient δ, θ=f(δ, SOS)... ...(1
1) and further stored in the output control device 21.

In the target medium temperature calculation device f1.28, the sulfuric acid removal rate θ' and the target medium temperature T, /, are stored in the memory circuit 28 in advance.
T,'=f(θ') ・・・・・・・・・(12
) is stored.

Based on the relationship in equation (12), the target medium temperature T is calculated using equation (13) from the sulfuric acid removal rate θ determined by equation (11), and is further output to the output control device 21.

'l'',=f(θ) ・・・・・・・・・(13
) In this way, the target medium temperature T is determined, and is output to the medium temperature output control device 22, and the chilled water pulp machine 15
control is performed to remove sulfuric acid from the exhaust gas.

Regarding the arrangement of the gas-to-gas heat exchanger of the present invention, the case where the frames are arranged in series with respect to the flow of exhaust gas has been explained, but the case where the frames in the gas-to-gas heat exchanger are arranged in parallel can also be extended to 80m.
By simply changing the relationship between 6 degrees and the corrected sulfuric acid dew point, it is possible to easily monitor and control exhaust gas using the method described above.

Although the power generation plant of the present invention has been described with the number of flue gas passages limited to one, even in the case of a plurality of passages, monitoring and control can be performed in exactly the same manner.

In the present invention, an example was described in which the medium temperature was controlled by sending cold water from a water cooler, but when the installation conditions of the power generation plant change, even if the control is performed using hot water or steam from a heating device, This can be easily achieved using the method of the present invention.

Furthermore, since the exhaust gas monitoring and control device outputs data during calculation to the output device, it becomes possible to monitor the processing equipment online, and it is possible to quickly respond to abnormalities in the plant.

〔Effect of the invention〕

According to the present invention, since sulfuric acid can be removed at a high rate in the flue gas treatment equipment of a power plant, the problem of exhaust gas pollution around the power plant can be solved.

[Brief explanation of drawings]

vJ1 diagram is a plant block diagram of an embodiment of the present invention,
Figure 2 is a detailed block diagram of the gas-gas heat exchanger in Figure 1, Figure 3 is a detailed diagram of the exhaust gas monitoring and control device in Figure 1, and Figure 4 is a detailed diagram of the exhaust gas monitoring and control device in Figure 1.
The figure is a detailed diagram of the exhaust gas removal arithmetic and control device shown in FIG. 3. DESCRIPTION OF SYMBOLS 1...Boiler, 2...Electric duster, 3...Gas/gas heat exchanger, 4...Desulfurizer, 5...Steam heater, 6...Steam heater, 7 ... Chimney, 8 ... Water cooler, 9 ... Exhaust gas monitoring control device, 10 ... Output device, 21 ... Output control device, 22 ... Medium temperature output control device M, 23.24゜25...Memory circuit 1.2.
3.26... Sulfuric acid removal rate calculation device, 27... Memory circuit 4.28... Target medium temperature calculation device, 29... Memory circuit 5

Claims (1)

[Claims] 1. Obtain the SO_3 concentration in the exhaust gas from the exhaust gas temperature in the exhaust gas treatment equipment of the power plant, and
3. Determine the sulfuric acid dew point temperature from the concentration and the moisture in the exhaust gas,
A corrosion coefficient is determined based on the sulfuric acid dew point temperature and the apparatus medium temperature, an exhaust gas removal rate is determined based on the corrosion coefficient and the SO_3 concentration, and further, the corrosion coefficient is maximized from the exhaust gas removal rate. An exhaust gas monitoring and control device characterized by comprising means for determining a target medium temperature of the device medium and controlling the opening and closing of a cold water valve of a water cooler so that the device medium temperature approaches the target medium temperature.