JP3958222B2 - Cleaning method in plant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning technique using a water flow in a system in which storage tanks, equipment and piping in a plant are combined, and more particularly to a cleaning method in a plant that requires a cleaning process in the system when a power plant or the like is started.
[0002]
[Prior art]
Generally, in the operation of a power plant such as a thermal power plant, impurities should not be mixed in the water supply. Therefore, as shown in the system diagrams of the plants in FIGS. 7 to 10 , in the system of the power plant in which the storage tank, the equipment, and the piping are combined, it is necessary to perform a cleaning process at the time of activation. For example, when a once-through boiler or the like is subjected to a cleaning process, the system is blow-cleaned, and the cleaning process is performed by circulating water through a desalting apparatus provided in the middle of the system.
[0003]
For example, when condensate cleanup is performed, the condensate pump 3 is operated as shown in the system diagram of FIG. 7 , and the blow valve B <b> 2 is set to “open” to perform blow cleaning to the blow tank 5. Next, after the water quality in the condenser 2 and the piping was stabilized, the valve (CV-2) was opened and the circulation operation was performed. At this time, water flow to the desalting apparatus 4 was started, and water quality treatment was performed in all subsequent steps. In the illustrated example, “thick solid line” indicates blow cleaning, and “thick broken line” indicates circulation cleaning.
[0004]
When performing low-pressure cleanup, as shown in the system diagram of FIG. 8 , water is passed from the low-pressure heater 6 to the deaerator 7, and the blow valve B 4 and the blow valve B 5 are set to “open” and blow-washed into the blow tank 5. It was. Next, after the water quality in the low pressure heater 6 and the deaerator 7 was stabilized, the valve V6 was opened and the circulation operation was performed.
[0005]
When performing high pressure cleanup, as shown in the system diagram of FIG. 9 , water is passed to the deaerator 7 in the low pressure cleanup system, the feed water pump 8 is operated, water is passed to the high pressure heater 9, and the blow valve B5 is turned on. The blow tank 5 was blow-washed with “open”. Next, after the water quality in the high-pressure heater 9 was stabilized, the valve V6 was opened and the circulation operation was performed.
[0006]
When the boiler cleanup is performed, as shown in the system diagram of FIG. 10 , water is passed to the boiler 1 through the high-pressure cleanup system, water is applied to the flash tank 10, the blow valve B 7 is opened, and the blow tank 5 is opened. Blow cleaning. Next, after the water quality in the boiler 1 and the piping was stabilized, the valve (CV-3) was opened and the circulation operation was performed.
[0007]
[Problems to be solved by the invention]
When the boiler is stopped during regular inspections, the storage tank, equipment, and piping may contain residual water from the time of stoppage, dust from construction, or chemicals for preventing corrosion. However, the conventional cleaning method has a problem that the processing time is long because impurities in the storage tank, equipment and piping are unnecessarily circulated in the system and adsorbed and removed by the desalting apparatus 4. For example, the time required for cleaning the plant system is about 11 to 12 hours. Here, the recent demand for electric power tends to increase or decrease rapidly depending on the consumer activities such as the industrial activities and the weather conditions such as the temperature with the spread of various electric devices such as air conditioning equipment. In order to respond to the sudden change in demand, the response of the power plant has become an important position in power supply operation, and it has been desired to shorten the time from the start command to the full load.
[0008]
Moreover, there existed a problem that the washing | cleaning frequency for reproducing | regenerating the desalinization apparatus 4 increased, and deterioration of resin advanced.
[0009]
Furthermore, there is a problem that a large amount of washing water is required to perform blow washing while filling the storage tank and equipment. For example, the washing water required for washing in the system of one power plant with a generator output of 700 MW class was about 2500 to 2700 tons.
[0010]
The present invention has been developed to solve such problems. That is, the object of the present invention is to first store a tank having a large water retention capacity in a system such as a condenser and a deaerator, blow once after water is applied to the device, and then store in the system up to the deaerator, By treating the impurities in the equipment and piping only by blow cleaning, the circulation cleaning step in the middle of the cleaning process can be omitted, and in the plant that can be cleaned in a short time and the amount of water used for the cleaning can be reduced It is to provide a cleaning method.
[0011]
[Means for Solving the Problems]
According to the first method of cleaning of the present invention, the condenser in a power plant (2), there at deaerator (7) and desalination device (4) a cleaning method for cleaning a system that combines a pipe Te, until after once filled with water to the condenser (2) and the deaerator (7), 該復condenser (2) and the dehydration-aerator (7) water quality in reaches the reference value the water filling and repeating the blow, then, after filled with water again the condenser (2), the equipment and piping between from the condenser (2) to said deaerator (7), a condensate pump According to (3) , there is provided a cleaning method in a plant characterized in that blow cleaning is performed while supplying cleaning water , and the water quality reaches a reference value and then water is passed to a desalting apparatus (4).
[0012]
The second method of cleaning, condenser of a power plant (2), deaerator (7), the low-pressure heater (6) and demineralizer (4) in the cleaning method of cleaning a system that combines a pipe there, after once filled with water to the condenser (2) and the deaerator (7), until 該復condenser (2) and the dehydration-aerator (7) water quality in reaches the reference value Repeated water filling and blowing, and then watered the condenser (2) again , and then the condenser (2) was blow-washed while supplying cleaning water by the condensate pump (3), the Rohm & low pressure heater (6) bypass to deaerator to (7), followed by blow after stretched again with water to dehydration-aerator (7), said deaerator wash water (7) in the method while supplying blowing washed, blown washed while supplying low pressure heater (6) washing water at the same time, the water flow that water quality after reaching the reference value, the desalter (4) That.
[0013]
In the above method, the water tank or equipment having a large water holding capacity in the system such as the condenser (2) and deaerator (7) constituting the power plant is first filled with water and then blown only with this water storage. By doing so, impurities in these storage tanks and equipment are discharged from the nearest valve, so that the time required for the cleaning process can be shortened. In addition, the amount of water used can be reduced as compared with a conventional cleaning method using both circulation cleaning and blow cleaning.
[0014]
Further, in the present invention, when washing a system in which a storage tank, equipment and piping are connected, the circulation washing step in the middle of the washing step is omitted. Impurities can prevent deterioration of the resin by not passing water through the desalting apparatus.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system diagram of a power plant that performs the cleaning method in the plant of the present invention. 2 to 6 are system diagrams of the power plant showing the cleaning method. In the illustrated example, “thick solid line” indicates blow or blow cleaning, and “thick broken line” indicates circulation cleaning.
In the cleaning method of the present invention, first, the condenser 2 and the deaerator 7 are once filled with water and then blown, and these are repeated until the water quality reaches a reference value, and then the condenser 2 is filled with water again. After that, the condensate pump 3 is blow-washed, the low-pressure heater 6 is bypassed, water is passed to the deaerator 7, water is refilled to the deaerator 7 and then blown, and the deaerator 7 is blow-washed. However, the inside of the low-pressure heater 6 is blow-cleaned, and after the water quality reaches the reference value, the water is passed through the desalting apparatus 4.
Here, “blow” refers to blowing with only stored water without supplying cleaning water, and “blow cleaning” refers to performing blowing while supplying cleaning water.
[0016]
FIG. 2 is a system diagram of a power plant showing a cleaning method for condensate cleanup.
First, when the water is blown after the water is once put in the condenser 2 and the deaerator 7 which are storage tanks and devices having a large water holding capacity in the system , as shown in FIG. B1 is opened and blown into the blow tank 5. The deaerator 7 is blown into the blow tank 5 by opening the blow valve B4 and the blow valve B5. For example, water filling and blowing of the condenser 2 are performed until the blow water quality measured by the water quality detector via the sampling pipe reaches the reference value, and is repeated a plurality of times if necessary. After the blow is completed, the blow valves B1, B4, B5 are closed.
[0017]
FIG. 3 is a system diagram of a power plant showing a cleaning method for condensate cleanup.
Next, when performing condensate cleanup, as shown in the figure, after the condenser 2 is filled with water, the condensate pump 3 is operated, the blow valve B2 is opened, and the blow tank 5 is blown. Wash. That is, after refilling the condenser 2 again, the valve V1 and the blow valve B2 are opened, and the pipe is blow-washed with the wash water passing through the condenser 2. At this time, cleaning water is appropriately supplied to the condenser 2. Pipe blow cleaning is performed until the blow cleaning water quality measured by the water quality detector through the sampling pipe reaches the reference value.
[0018]
The measurement items of the water quality detector vary depending on the purpose of the system. In the case of a power plant, turbidity, iron, hydrazine or dissolved oxygen are inspection items. In a system showing a strong correlation between turbidity and iron, iron can be measured instead of turbidity. Water quality can be measured not only automatically but also manually.
[0019]
Moreover, it can replace with a manual analysis and the measurement by a water quality detector, and can implement by management of the washing | cleaning time. This cleaning time is set according to the type of the device to be cleaned and the stop time. For example, when it is known as a rule of thumb that the cleaning process is completed in a short time, it is possible to manage the cleaning time using a timer and proceed to the next process.
[0020]
FIG. 4 is a system diagram of a power plant showing a cleaning method for low-pressure heater bypass cleanup. FIG. 5 is a system diagram of a power plant showing a cleaning method for low-pressure heater cleanup.
When cleaning up the deaerator 7 and the low-pressure heater 6, first, as shown in the system diagram of FIG. 4 , the low-pressure heater 6 is bypassed and water is passed to the deaerator 7. After filling the water, the blow valve B4 and the blow valve B5 are opened and blown into the blow tank 5. Next, as shown in the system diagram of FIG. 5, while the deaerator 7 is being cleaned up, the valve V4 and the blow valve B3 are opened, and the low pressure heater 6 is extruded and blow cleaned.
[0021]
FIG. 6 is a system diagram of the power plant showing the circulation method after the low-pressure heater cleanup.
As the deaerator 7 and the low-pressure heater 6 are cleaned up, the water quality of the system reaches a reference value, and then, as shown in the figure, the water is passed through the demineralizer 4 to perform a circulation process.
[0022]
In a conventional power plant system, a cleaning time of about 11 hours was required in a method using blow cleaning and circulation cleaning at the time of startup. In the cleaning method in which the cleaning of the deaerator and the low-pressure heater according to the present invention is completed, i.e., the circulation cleaning in the middle of the cleaning process is omitted, a water tank or device having a large water holding capacity is once filled with water and then blown. In addition, since the impurities in the system can be discharged from the latest valve, cleaning was completed in about 8 hours.
As for the amount of water to be used, about 2500 tons were required in the method using blow, blow cleaning and circulating cleaning in combination, but in the cleaning method of the present invention, cleaning was possible at about 1500 tons.
[0023]
In addition, about a storage tank, an apparatus, and piping, it is also possible to wash | clean multiple apparatuses simultaneously, such as not only the method to wash | clean sequentially but in this way. It is also possible to proceed to the next step without completing the cleaning in each step. Whether the cleaning is performed sequentially or simultaneously is determined in consideration of the supply capacity and drainage capacity of the cleaning water. In this case, the cleaning can be completed more quickly by proceeding with the cleaning at the same time.
[0024]
The present invention is not limited to the embodiment of the invention described above. First, the storage tank or equipment such as the condenser 2 or deaerator 7 having a large water retention capacity is first filled in the system and then blown. Thus, the gist of the present invention can be obtained if it is a cleaning method that discharges impurities from the latest valves B1, B4, B5, etc., and sequentially blows and blow-cleans downstream devices, and eliminates the need for circulating cleaning during the cleaning process. Of course, various changes can be made without departing from the scope.
[0025]
【The invention's effect】
In the washing method in the plant of the present invention, first, water is once applied to a device having a large water holding capacity in a system such as a condenser and a deaerator, then blown, and then water is added again, and a downstream storage tank This is a method that eliminates the circulation cleaning process until the cleaning of the deaerator and the low-pressure heater, which has been performed in the past, is completed, that is, the circulation cleaning process in the middle of the cleaning process. It can be shortened. Therefore, it is possible to shorten the time required for starting up a plant such as a thermal power plant, and it is possible to contribute to the improvement of power supply operability.
[0026]
Moreover, according to the cleaning method of the present invention, the amount of water used for plant cleaning can be reduced as compared with a conventional method using both circulation cleaning and blow cleaning.
[0027]
Furthermore, since the cleaning method of the present invention does not perform water quality treatment by the desalting apparatus at the time of each cleanup with the highest load on the desalting apparatus until the cleaning of the deaerator and the low-pressure heater is completed. Since it is possible to reduce the number of times chemical cleaning is performed, the cost of cleaning chemicals and environmental impact are reduced, and impurities are not circulated in the system, so the failure rate of equipment, etc. decreases. There is an effect.
[Brief description of the drawings]
FIG. 1 is a system diagram of a power plant that performs a cleaning method in a plant of the present invention.
FIG. 2 is a system diagram of a power plant showing a cleaning method for condensate cleanup.
FIG. 3 is a system diagram of a power plant showing a cleaning method for condensate cleanup.
FIG. 4 is a system diagram of a power plant showing a cleaning method for low-pressure heater bypass cleanup.
FIG. 5 is a system diagram of a power plant showing a cleaning method for low-pressure heater cleanup.
FIG. 6 is a system diagram of a power plant showing a circulation method after cleanup of a low-pressure heater.
FIG. 7 is a system diagram of a power plant showing a cleaning method for cleaning up condensate in a conventional power plant such as a thermal power plant.
FIG. 8 is a system diagram of a power plant showing a cleaning method for performing low-pressure cleanup of a power plant such as a conventional thermal power plant.
FIG. 9 is a system diagram of a power plant showing a cleaning method for performing high-pressure cleanup of a power plant such as a conventional thermal power plant.
FIG. 10 is a system diagram of a power plant showing a cleaning method for cleaning up a boiler of a power plant such as a conventional thermal power plant.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Boiler 2 Condenser 3 Condensate pump 4 Desalination apparatus 6 Low pressure heater 7 Deaerator 8 Water supply pump 9 High pressure heater 10 Flash tank

Claims (2)

Condenser in a power plant (2), a deaerator (7) and desalination device (4) a cleaning method for cleaning a system that combines a pipe,
After once filled with water to the condenser (2) and the deaerator (7), the water filling and blow up 該復condenser (2) and the dehydration-aerator (7) Water quality in reaches the reference value Repeat
Then washed, filled with water again the condenser (2), the equipment and piping between from the condenser (2) to said deaerator (7), the condensate pump (3) Blow cleaning while supplying water ,
A washing method in a plant, wherein the water quality reaches a reference value and then water is passed to a desalinator (4). Condenser of the power plant (2), deaerator (7), a cleaning method for cleaning a system that combines a pipe low pressure heater (6) and demineralizer (4),
After once filled with water to the condenser (2) and the deaerator (7), the water filling and blow up 該復condenser (2) and the dehydration-aerator (7) Water quality in reaches the reference value Repeat
Next, after watering the condenser (2) again, the condenser (2) is blow-washed while supplying washing water by the condenser pump (3),
The Rohm & low pressure heater (6) Bypass to deaerator to (7), followed by blow after stretched again with water to dehydration-aerator (7),
The deaerator (7) is blow-washed while supplying cleaning water, and at the same time the low-pressure heater (6) is blow-washed while supplying cleaning water ,
A washing method in a plant, wherein the water quality reaches a reference value and then water is passed to a desalinator (4).

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