JPS5912287A - Shellfish-removing device for condenser cooling water - Google Patents

Abstract

PURPOSE:To prevent the efficiency in removing foreign matter from being lowered, by a method wherein a blow valve for discharging a portion of condenser-cooling water is controlled in accordance with inlet and outlet temperatures of cooling water or the difference between the inlet temperature and the outlet temperature. CONSTITUTION:In the case where cooling water pumped up by a circulating water pump 1 is fed to a condenser 2 through a cooling water supplying pipe 7, when a large amount of foreign matter adheres to a filter in the shellfish-removing device 3 and a pressure difference detector 6 is operated, a signal therefrom is fed to an inlet valve 4 and the blow valve 5, whereby the inlet valve 4 it set to a washing opening for generating a vortex while the blow valve 5 is fully opened. When blow quantity becomes larger than a required quantity and the quantity of condenser-cooling water is reduced, the outlet temperature of cooling water is raised. When the inlet and outlet temperatures of cooling water are detected respectively by temperature detectors 10 and 11 and signals therefrom are sent to a temperature regulator 12, a signal for throttling the blow valve 5 is outputted if the difference between the two temperatures is larger than a prescribed temperature difference. When the prescribed temperature difference is set to an inlet-outlet temperature difference for a cooling water quantity taking into account a required blow quantity of 10%, a required quantity of cooling water is constantly secured irrespectively of the sea water level.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shell removal device installed in a condenser cooling water system of a thermal power or nuclear couplant, which generates a vortex to broach foreign matter adhering to a filter.

Most of the time, seawater is used as a cooling water source for condensers, and marine organisms are also carried to the condensers.

If these marine organisms adhere to the condenser cooling pipe, it will lead to a decline in plant performance, so one way to prevent this is to use a vortex filter type shell removal device R (hereinafter referred to as a shell removal device). In general, shell removal equipment removes foreign objects (marine organisms, etc.) contained in the cooling water, sends the foreign object-free cooling water to the condenser, and when a certain amount of foreign objects adhere to the filter, it detects the differential pressure and removes the shells. The device's artificial valve is set to the cleaning opening to create a vortex and blow away foreign matter. Here, a conventional method of controlling and operating a shell removal device will be outlined with reference to FIG.

The condenser cooling water is pumped up from the water intake pit by the circulating water pump l, and is sent to the condenser 2 through the cooling water supply pipe 7. After exchanging heat with the turbine exhaust in the condenser 2, the coolant whose temperature has increased passes through the coolant return pipe 8 and is drained to the water discharge bit. During this time, foreign matter contained in the cooling water is continuously removed by a shell removal device 3 provided on the condenser 2 side. When a large amount of foreign matter adheres to the filter in the shell removal device 3, the differential pressure between the inside and outside of the filter is detected by the differential pressure detector 6, and at a certain required pressure, the large opening valve 4 is cleaned and the blow valve 5 is fully opened. A signal is sent, and the foreign matter adhering to the filter is removed by the vortex flow, passed through the entire blow pipe 9, and discharged to the water discharge pit.

In general, it is said that this blowing amount is required to be approximately 10% of the artificial flow rate (condenser cooling water amount) of the shell removal device 3 in order to satisfy the removal performance9. is said to be significantly reduced. Therefore, when the artificial flow rate of the shell removal device 3 is 100%, it is necessary to size the blow tube 9 so that the blow amount is 10% or more under any operating conditions. However, the following problems arise when carrying out such a plan.

The seawater level varies greatly depending on the tide, and the amount of blow water varies depending on the ebb and flow.
Under any conditions, if 10% of the amount of cooling water is to be secured, it is naturally necessary to design at the lowest seawater level (LWL). On the other hand, at high tide, the seawater level rises, and as a result, the pressure at one point in the blow of the shell removal device rises, and the amount of water blown increases accordingly. In this case, the amount of cooling water to the condenser decreases, which leads to deterioration of plant performance and environmental problems due to the temperature difference between the outlet and outlet of the condenser cooling water becoming large and resulting in hot wastewater. Figure 2 shows these mutual relationships.
This will be explained with reference to FIGS. 3, 4, and 5.

FIG. 2 is a diagram of the hydraulic gradient of the condenser cooling water system, where the curve ■ indicates when the seawater level is at HWL, and the curve ■ indicates when the seawater level is at LWL. Since the pumping head of the circulating water pump 1 is the same at either seawater level, the amount of cooling water does not change. On the other hand, the pressure at one point in the shell removal equipment blower is at seawater level HW.
The point ■ at L time is p, and the point @ at LWL. Here, the blow water discharge end of the shell removal device is held down at a height that is not affected by the seawater level in order to discharge foreign matter. Therefore, the amount of blow water depends on the pressure at one blow point. Figure 3 shows the relationship between the blow pressure required at one point, the system resistance, and the blow amount. H,
In FIG. 2, is the pressure at the point @, and at this time, the blow amount is set to 10% to determine the system resistance and size the blow tube. If the seawater level rises and the required pressure at one blow point rises to HR, the blow amount will be about 15%, which is the balance point with the system resistance. As a result, the amount of condenser cooling water decreased by 85% in the casing.
, the temperature difference between the condenser cooling water inlet and outlet becomes large. Figure 4 shows the relationship. If the condenser inlet and outlet temperature difference when the condenser cooling water amount is 90% is ΔT, if the condenser cooling water amount decreases to 85%, the condenser inlet and outlet temperature difference will increase to ΔT. . Differences in condenser cooling water temperature cause thermal wastewater to sink, which is also an environmental issue, and a plan that takes this point into consideration is required. Furthermore, Fig. 5 shows the relationship between the condenser cooling water amount and the condenser vacuum degree, and as is clear from this figure, when the cooling water amount is 100%, the vacuum degree 'r P
If the amount of cooling water is reduced to 80%, the degree of vacuum will drop to P, resulting in a decline in plant performance.

An object of the present invention is to provide a condenser cooling water shell removal device that eliminates the problem of deterioration in plant performance.

An embodiment of the present invention will be described with reference to FIGS. 6 and 7.

Figure 6 shows the relationship between the pressure required at one blow point, the system resistance, and the amount of water blown.First of all, the amount of blowing required to satisfy the first condition, the performance of the shell removal device, is determined as explained in Figure 3. , at the required pressure H at one blow point. If the blow amount could be kept constant regardless of the seawater level, all of the above-mentioned problems would be solved. Therefore, even if the seawater level rises and the required pressure at one blow point becomes Hz, in order to achieve the same blow amount as in the case of Hl,
It is necessary to increase the system resistance of the blow line from t to . As a means of this, it is possible to increase the system resistance by a large amount by throttling the blow valve to compensate for the pressure difference between I(, and H). Figure 7 shows the content explained in Figure 6. It is a condenser cooling water system diagram for concretely explaining.

The basic control method and operation method of the shell removal device are the same as those explained in Fig. 1, but a new method is to detect the temperature of the condenser cooling water inlet and outlet, and to remove shells based on the temperature difference. It has an added function to control the blow valve of the device. now,
It is assumed that the cooling water pumped up by the circulating water pump 1 is normally sent to the condenser 2 through the cooling water supply pipe 7.

Here, if a large amount of foreign matter adheres to the filter in the shell removal device 3 and the differential pressure detector 6 operates, the signal will be transmitted to the large mouth valve 4.
The water is then sent to the blow valve 5, and the large mouth valve 4 is opened at a washing opening to generate a vortex flow, and the blow valve 5 is fully opened.

At this time, if the blow amount becomes larger than the required amount and the condenser cooling water value decreases, the condenser cooling water outlet temperature will rise if the condenser heat load is constant. Therefore, the temperature detector 10 provided on the condenser cooling water inlet side and the temperature detector 11 provided on the outlet side detect the entire temperature of the condenser cooling water inlet and outlet, and the signal is used to detect the temperature difference. It is sent to regulator 12. When the temperature difference is larger than a specified temperature difference, a signal is sent to the temperature difference regulator 12 to throttle and control the blow valve 5. Here, the specified temperature difference of the temperature difference regulator 12 is set in advance to the required blow amount lO%.
If the condenser cooling water amount is set to the condenser cooling water inlet/outlet temperature difference determined as the condenser temperature drainage condition, no matter what the seawater level is, the required condenser will always be maintained. It is possible to secure the amount of cooling water, and it will also be possible to greatly contribute to countermeasures against environmental problems in the form of heated wastewater.

[Brief explanation of the drawing]

Figure 1 is a conventional condenser cooling water system diagram with a shell removal device;
The figure is a hydraulic gradient diagram showing the pressure distribution of the condenser cooling water system, Figure 3 is an explanatory diagram showing the relationship between pressure at one point of the shell removal equipment blow and blow value as system resistance, Figure 4 is: Figure 5 is a diagram showing the relationship between the amount of cooling water in the condenser and the temperature difference between the inlet and outlet. Figure 5 is a diagram showing the relationship between the amount of cooling water in the condenser and the degree of vacuum in the condenser chamber. Figure 6 is the value of blown water by the device of the present invention. FIG. 7 is an overall system diagram showing a condenser cooling water shell removal device according to an embodiment of the present invention. 2... Condenser, 3... Shell removal device, 4... Population valve,
5... Blow valve, 6... Differential pressure detector, 7... Cooling water supply pipe, 9... Blow pipe, 10.11... Temperature detector, 12... Diagram θ for warming s 10 15

Claims (1)

[Claims] In a shell removal device that is installed in a condenser cooling water system of a 1° thermal power nuclear couplant and removes foreign matter adhering to a filter by creating a vortex, the condenser cooling water inlet and outlet temperatures, or these temperatures. A condenser cooling water shell removal device characterized in that a blow valve for discharging a portion of cooling water from the shell removal device is controlled to a required opening degree based on the difference.