JP2017181334A - Sample collector and method for controlling the sample collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample collector which can supply or store sample water to or in an electrode-type water quality analyzer at an appropriate timing according to the operation situation of a power generation plant, and a method for controlling the sample collector.SOLUTION: The sample collector of a thermal power plant has a boiler water analysis system, and the boiler water analysis system includes: a pH meter 116 for boiler water for analyzing the pH of boiled water; a supply valve 115 for supplying the boiler water to the pH meter 116; and a discharge valve 117 for discharging the analyzed boiler water from the pH meter 116. A unit calculator 7 prevents degradation by drying of an analysis electrode 116c, by closing the supply valve 115 and the discharge valve 117 when the unit of the thermal power plant is stopped to prevent the boiler water in a measuring tank 116a from being discharged and then immersing the analysis electrode 116c in the boiler water.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sampling device for collecting sample water such as can water and analyzing the water quality in a power plant such as a thermal power plant, and a control method therefor.

  In power plants such as thermal power plants, water quality such as boiler water and condensate is analyzed and water quality is adjusted based on the analysis results in order to prevent plant accidents caused by water quality. . In order to perform such water quality analysis and water quality adjustment, the power generation plant is provided with a sampling device that can collect the sample water at each point in the plant and perform water quality analysis.

  A conventional sample collection device is supplied with a sample valve for collecting sample water such as can water and condensate from a boiler, and a supply valve for supplying sample water collected by the sample valve to an electrode-type water quality analyzer. An electrode-type water quality analyzer that analyzes the quality of the sample water using an analysis electrode, and a discharge valve that discharges the analyzed sample water from the electrode-type water quality analyzer (see, for example, Patent Document 1).

  An electrode-type water quality analyzer is an analyzer that analyzes the water quality of sample water based on a potential difference generated between the working electrode and the reference electrode by immersing an analytical electrode having a working electrode and a reference electrode in the sample water. Examples include a pH meter, an electric conductivity meter, and a hydrazine meter. If the analysis electrode is deteriorated by drying, the analysis accuracy may be lowered and the response may be delayed. Therefore, it is necessary to immerse the electrode in pure water or sample water so as not to be dried when not in use.

  In the sampling device of Patent Document 1, when analyzing the quality of the sample water, the sample valve, the supply valve, and the discharge valve are opened, and the quality of the sample water is analyzed by the electrode-type water quality analyzer. When stopping the water quality analysis of the sample water, open the dummy water valve connected to the electrode-type water quality analyzer, inject pure water, close the supply valve and the discharge valve, and put it in the electrode-type water quality analyzer. Pure water is retained, and the electrode for analysis is immersed in pure water to prevent drying.

JP 2009-025101 A

  The sampling device supplies sample water to the electrode-type water quality analyzer at an appropriate timing during unit operation of the power plant. Similarly, when the unit is stopped, pure water is retained in the electrode-type water quality analyzer at the appropriate timing. There must be. However, since the sampling apparatus of Patent Document 1 does not automatically open and close the supply valve and the discharge valve, the supply valve and the discharge valve may not be opened and closed at an appropriate timing. In particular, if the supply of pure water or sample water to the electrode-type water quality analyzer is delayed when the operation of the power plant unit is stopped, the analysis electrode is dried and deteriorated. When the analytical electrode is dried and deteriorated, it takes time and cost because a dry countermeasure treatment of immersing and calibrating in pure water or a pH standard solution for about half a day to one day must be performed.

  An object of the present invention is to provide a sampling device capable of supplying or retaining sample water to an electrode-type water quality analyzer at an appropriate timing according to the operating state of a power plant, and a control method for the sampling device. To do.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a sampling device that collects sample water of a power plant and analyzes the quality of the sample water using an electrode-type water quality analyzer. Valve for supplying water to the electrode-type water quality analyzer, a discharge valve for discharging the analyzed sample water from the electrode-type water quality analyzer, and opening the supply valve and the discharge valve when the power plant unit is operating. Control means for supplying sample water to the meter, closing the supply valve and the discharge valve when the unit is stopped, retaining the sample water in the electrode-type water quality analyzer, and immersing the analysis electrode of the electrode-type water quality analyzer in the sample water; Is provided.

  According to the first aspect of the present invention, the sample collection device for collecting the sample water of the power plant and analyzing the water quality includes the electrode type water quality analyzer for analyzing the water quality of the sample water with the analysis electrode, and the collected sample. A supply valve for supplying water to the electrode-type water quality analyzer, a discharge valve for discharging the analyzed sample water from the electrode-type water quality analyzer, and a control means for controlling the supply valve and the discharge valve are provided. The control means opens the supply valve and the discharge valve during unit operation of the power plant to supply sample water to the electrode-type water quality analyzer, and closes the supply valve and discharge valve when the unit is stopped to close the electrode-type water quality analyzer. The sample water is retained in the sample, and the analysis electrode is immersed in the sample water to prevent deterioration due to drying.

  Invention of Claim 2 is equipped with the supply pump which can switch supply of sample water and supply stop to an electrode type water quality analyzer according to the operation situation of a unit in the sampling device of Claim 1 The control means opens the supply valve and the discharge valve when the supply pump starts supplying sample water, and closes the supply valve and the discharge valve when the supply pump stops supplying sample water.

  A third aspect of the present invention is the sampling apparatus according to the first or second aspect, further comprising a plurality of sample analysis systems including a supply valve, an electrode-type water quality analyzer, and a discharge valve. Centrally control the sample water analysis system.

  According to a fourth aspect of the present invention, in the sampling device according to any one of the first to third aspects, the electrode-type water quality analyzer is configured to analyze the sample water supplied from the supply valve with the analysis electrode. And a discharge tank that is connected to the analysis tank and discharges the analyzed sample water flowing from the analysis tank through the discharge valve.

  According to a fifth aspect of the present invention, in the sample collection device according to any one of the first to fourth aspects, the sample water is a liquid that requires water quality monitoring such as boiler water.

  The invention according to claim 6 is a supply valve for supplying sample water of a power plant to an electrode-type water quality analyzer, a discharge valve for discharging analyzed sample water from the electrode-type water quality analyzer, a supply valve and a discharge valve And a control means for controlling the sampling device, and the control means opens the supply valve and the discharge valve during unit operation of the power plant to supply sample water to the electrode-type water quality analyzer, When the unit is stopped, the supply valve and the discharge valve are closed, the sample water is retained in the electrode-type water quality analyzer, and the analysis electrode of the electrode-type water quality analyzer is immersed in the sample water.

  According to the first and sixth aspects of the invention, since the sample water is supplied to the electrode-type water quality analyzer by opening the supply valve and the discharge valve during unit operation of the power plant, the plant configuration resulting from the quality of the sample water Corrosion accidents of materials can be prevented. Further, when the unit is stopped, the supply valve and the discharge valve are closed, the sample water is retained in the electrode-type water quality analyzer, and the analysis electrode is immersed in the sample water, so that deterioration due to drying of the analysis electrode can be prevented. . Therefore, according to the sampling device of the present invention, even when the power plant unit is stopped for a long period of time, it is possible to prevent the analysis electrode from being dried. Will be able to use. In addition, since it is not necessary to take a measure against drying of the analysis electrode at the start of the unit operation, the time and cost for the treatment can be reduced.

  According to the second aspect of the present invention, since the supply valve and the discharge valve are controlled according to the operation state of the supply pump that supplies and stops the supply of the sample water, sampling of the sample water is actually started. The supply and retention of the sample water to the electrode-type water quality analyzer can be switched at the timing when the sampling of the sample water is stopped or when the sampling of the sample water is stopped. Accordingly, unnecessary supply and retention of sample water to the electrode-type water quality analyzer can be prevented as compared with the case where control is performed according to the operation status of the unit.

  According to the third aspect of the present invention, since the plurality of sample analysis systems can be comprehensively controlled by the control means, the type of sample water is such as make-up water, can water, condensate, and generated steam. Even in various cases, the analysis electrode of each sample analysis system can be protected from drying.

  According to the invention described in claim 4, the measuring tank in which the sample water of the electrode type water quality analyzer is retained, the analysis tank for analyzing the sample water with the electrode for analysis, and the discharge valve for the analyzed sample water For example, when sample water is retained in the electrode-type water quality analyzer, even if the sample water leaks from the discharge tank due to a failure of the discharge valve, the analysis tank Since leakage of sample water from the inside can be prevented, deterioration due to drying of the analysis electrode can be prevented.

  According to the invention described in claim 5, since the sample water can be applied to liquids that require water quality monitoring such as boiler can water, it can be used for collecting and analyzing various types of sample water. Can do.

It is the schematic which shows the structure of a thermal power plant. It is a schematic system diagram which shows the structure of a sample-collecting apparatus. It is the schematic which shows the structure of the pH meter for can water, a supply valve, and a discharge valve. It is a flowchart which shows the control procedure of a supply valve and a discharge valve.

  The present invention will be described below based on the illustrated embodiments.

  FIG. 1 is a schematic diagram showing a configuration of a thermal power plant (power plant) 1 provided with a sampling device of the present invention. The thermal power plant 1 includes a plurality of units including a boiler 2, a turbine 3, a generator 4, a condenser 5, a sampling device 6, a unit computer (control means) 7, and the like.

  The boiler 2 heats makeup water using coal, oil, natural gas, or the like as fuel to generate steam. The turbine 3 drives the generator 4 with the steam generated by the boiler 2 to cause the generator 4 to generate power. The condenser 5 condenses the steam discharged from the turbine 3 to generate condensate, and supplies the generated condensate to the boiler 2 as makeup water.

  The sample collection device 6 collects the can water in the boiler 2 and the condensate in the condenser 5 as sample water in order to prevent performance degradation due to corrosion of equipment such as piping and scale generation, and analyzes the water quality. Canned water and condensate are collected through sample valves 111 and 121. The unit computer 7 is a computer system that comprehensively controls the thermal power plant 1 as a whole, and also controls the sampling device 6 as the control means of the present invention. The sampling device 6 and the unit computer 7 protect the analysis electrode of the pH meter (electrode type water quality analyzer) in the sampling device 6 from drying when the unit is stopped for a long time.

  FIG. 2 is a schematic system diagram showing the configuration of the sample collection device 6. The sample collection device 6 includes a cooling water supply channel 8A, a cooling water drain channel 8B, a sample water drain channel 9A, a sample water recovery channel 9B, and the like. The cooling water supply path 8A and the cooling water drain path 8B are pipes for supplying and draining cooling water used for cooling the sample water to a plurality of sample analysis systems. The sample water drainage channel 9A is a conduit for draining the analyzed sample water toward the wastewater treatment device. The sample water recovery path 9B is a pipe line for recovering the analyzed sample water as makeup water.

  The sample collection device 6 includes a plurality of sample analysis systems such as a can water analysis system 11 and a condensate analysis system 12 in order to collect and analyze a plurality of types of sample water such as makeup water, can water and condensate. . The unit computer 7 as control means controls the can water analysis system 11 and the condensate analysis system 12 in an integrated manner.

  The can water analysis system 11 is an analysis system for collecting and analyzing can water from the boiler 2, a sample valve 111 for collecting can water from the boiler 2, a cooler 112, a supply pump 113, and a head vessel. 114, a supply valve 115, a can water pH meter 116, and a discharge valve 117.

  The cooler 112 is connected to the cooling water supply path 8A and the cooling water drain path 8B, and cools the can water supplied from the sample valve 111 with the cooling water. The supply pump 113 is a pump for supplying can water to the can water pH meter 116, and can be switched between supply and stop of supply of can water according to the operation status of the unit. The head vessel 114 applies a constant water pressure to the can water pH meter 116 to stabilize the flow rate of the can water.

  The supply valve 115 supplies canned water to the can water pH meter 116, and the discharge valve 117 is a valve for discharging the analyzed can water from the can water pH meter 116. The opening and closing of the supply valve 115 and the discharge valve 117 are controlled by the unit computer 7.

  As shown in FIG. 3A, a can water pH meter (electrode-type water quality analyzer) 116 is provided in a measuring tank 116a in which the can water supplied from the supply valve 115 is stored, and an upper part of the measuring tank 116a. The analysis electrode 116c inserted from the opened opening 116b, a lid 116d that opens and closes the opening 116b, and a main body cover 116e that covers the entire measuring tank 116a.

  The measurement tank 116a is connected to the analysis tank 116f for analyzing the can water supplied from the supply valve 115 by the analysis electrode 116c, and the analyzed pipe that is connected to the analysis tank 116f by the communication portion 116g and flows from the analysis tank 116f. A discharge tank 116 h for discharging water from the discharge valve 117.

  The analysis electrode 116c includes a working electrode and a reference electrode (not shown), and is an analyzer that analyzes the pH (water quality) of the pipe water based on a potential difference generated between the working electrode and the reference electrode. If the analysis electrode 116c is deteriorated by drying, the analysis accuracy may be lowered and the response may be delayed. Therefore, when the can water pH meter 116 is not used, it is necessary to treat the analytical electrode 116c so that it does not dry.

  The unit computer 7 controls the opening and closing of the supply valve 115 and the discharge valve 117 according to the operation status of the supply pump 113, that is, the operation status of the unit. 117 is closed and the can water is retained in the measuring tank 116a. Then, the analysis electrode 116c is immersed in the retained can water to prevent the analysis electrode 116c from being deteriorated due to drying.

  The condensate analysis system 12 is an analysis system for collecting and analyzing condensate from the condenser 5, and similarly to the can water analysis system 11, the sample valve 121, the supply pump 123, the head vessel 124, the supply valve 125, a condensate pH meter 126, a discharge valve 127, and the like. In addition, since these structures are the same as that of the can water analysis system | strain 11, detailed description is abbreviate | omitted.

  Next, the operation of the sample collection device 6 and the unit computer 7 will be described with reference to the flowchart of FIG. When the supply pumps 113 and 123 are operated (YES in step S1), that is, when the unit starts operation, the unit computer 7 uses the sample valves 111 and 121, the supply valves 115 and 125, and the discharge valves 117 and 127. Are opened (step S2). As a result, as shown in FIG. 3A, the can water and the condensate are supplied to the can water pH meter 116 and the condensate pH meter 126 by the supply pumps 113 and 123. The pH of the can water and the condensate is analyzed by the condensate pH meter 126 (step S3). The analyzed can water and condensate are discharged to the sample water drainage channel 9A via the discharge valves 117 and 127.

  When the supply pumps 113 and 123 are stopped (YES in step S4), that is, when the unit stops operation, the unit computer 7 uses the sample valves 111 and 121, the supply valves 115 and 125, and the discharge valves 117 and 127. Are closed (step S5). As a result, as shown in FIG. 3B, the can water and the condensate are retained in the measuring tank 116a of the can water pH meter 116 and the condensate pH meter 126, respectively, and the analysis electrode 116c is immersed. Therefore, deterioration due to drying of the analysis electrode 116c can be prevented.

  According to the present embodiment, during operation of the unit, the supply valves 115 and 125 and the discharge valves 117 and 127 are opened to supply can water and condensate to the pH meters 116 and 126, and the water quality of the can water and condensate is analyzed. Therefore, it is possible to prevent accidents caused by corrosion of plant components due to the water quality of canned water and condensate. Further, when the unit is stopped, the supply valves 115 and 125 and the discharge valves 117 and 127 are closed, the can water and condensate are retained in the pH meters 116 and 126, and the analysis electrode 116c is immersed in the can water and condensate. It is possible to reliably prevent deterioration due to drying of the analysis electrode 116c. Therefore, even when the unit is stopped for a long period of time, the analysis electrode 116c can be prevented from drying, so that the pH meters 116 and 126 can be used immediately at the start of operation. In addition, since it is not necessary to perform the dry countermeasure process for the analysis electrode 116c at the start of the unit operation, the time and cost for the process can be reduced.

  In addition, since the supply valves 115 and 125 and the discharge valves 117 and 127 are controlled in accordance with the operating conditions of the supply pumps 113 and 123 that supply and stop the supply of canned water and condensate, The supply and retention of the sample water with respect to the pH meters 116 and 126 can be switched at the timing when the sampling is actually started or when the sampling is stopped. Therefore, it is possible to prevent unnecessary supply and retention of sample water to the pH meters 116 and 126 as compared with the case where control is performed according to the operation status of the unit.

  Furthermore, since a plurality of sample analysis systems can be comprehensively controlled by the unit computer 7, each sample analysis can be performed even when there are various types of sample water such as makeup water, can water, condensate, and generated steam. The analytical electrode of the system can be protected from drying.

  Further, the measuring tanks of the pH meters 116 and 126 are divided into an analysis tank 116f for analyzing the sample water by the analysis electrode 116c and a discharge tank 116h for discharging the analyzed sample water. Even when the sample water leaks from the discharge tank 116h due to a failure of the discharge valves 117 and 127 while the sample water is retained in the pH meters 116 and 126, the sample water is prevented from leaking from the analysis tank 116f. Degradation due to drying of the analysis electrode 116c can be prevented. Furthermore, since it can apply to the liquid which requires water quality monitoring including boiler can water as sample water, it can utilize for collection and analysis of various kinds of sample water.

  Although the embodiment of the present invention has been described in detail above, the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention, include. For example, the opening and closing of the supply valves 115 and 125 and the discharge valves 117 and 127 are controlled in accordance with the operating conditions of the supply pumps 113 and 123, but the supply valve 115 is not used depending on the pressure of the sample water. , 125 and the discharge valves 117 and 127 can be opened to supply sample water to the water quality analyzer. Therefore, when the present invention is applied to such a sample analysis system that does not use a supply pump, the opening and closing of the supply valves 115 and 125 and the discharge valves 117 and 127 may be controlled according to the operation status of the unit.

  Further, although the pH meters 116 and 126 have been described as examples of electrode-type water quality analyzers, they can also be applied to electrical conductivity meters, hydrazine meters, silica / phosphate meters, and the like. Furthermore, although the sample water is retained in the pH meters 116 and 126, pure water may be retained instead of the sample water. In this case, a tank for storing pure water and a valve for supplying pure water from the tank to the pH meters 116 and 126 are provided, and pure water is supplied after the sample water is discharged from the pH meters 116 and 126. As described above, the control may be performed by the unit calculator 7.

1 Thermal power plant (power plant)
2 Boiler 6 Sampling device 7 Unit computer (control means)
11 Canned water analysis system (sample analysis system)
111 Sample valve 113 Supply pump 115 Supply valve 116 pH meter for canned water (electrode type water quality analyzer)
116c Electrode for analysis 116f Analysis tank 116h Discharge tank 117 Discharge valve 12 Condensate analysis system (sample analysis system)
121 Sample valve 123 Supply pump 125 Supply valve 126 Condensate pH meter (Electrode water quality analyzer)
127 discharge valve

Claims (6)

A sampling device that collects sample water of a power plant and analyzes the quality of the sample water with an electrode-type water quality analyzer,
A supply valve for supplying the collected sample water to the electrode-type water quality analyzer;
A discharge valve for discharging the analyzed sample water from the electrode-type water quality analyzer;
When the unit of the power plant is operated, the supply valve and the discharge valve are opened to supply sample water to the electrode-type water quality analyzer, and when the unit is stopped, the supply valve and the discharge valve are closed and the electrode-type water quality analysis is performed. Control means for retaining the sample water in the meter and immersing the electrode for analysis of the electrode-type water quality analyzer in the sample water;
A sampling apparatus comprising: A supply pump that can switch supply and stop of sample water to the electrode-type water quality analyzer according to the operation status of the unit,
The control means opens the supply valve and the discharge valve when the supply pump starts supplying sample water, and closes the supply valve and the discharge valve when the supply pump stops supplying sample water.
The sampling apparatus according to claim 1. A plurality of sample analysis systems including the supply valve, the electrode-type water quality analyzer, and the discharge valve; and the control means controls the plurality of sample analysis systems in an integrated manner.
The sampling apparatus according to claim 1 or 2, characterized by the above. The electrode-type water quality analyzer is connected to an analysis tank for analyzing the sample water supplied from the supply valve by the electrode for analysis, and the analyzed sample water that is communicated with the analysis tank and flows from the analysis tank. A discharge tank for discharging from the discharge valve;
The sampling apparatus according to any one of claims 1 to 3, further comprising: The sample water is a liquid that requires water quality monitoring including boiler water.
The sampling apparatus according to any one of claims 1 to 4, wherein A supply valve for supplying sample water of the power plant to the electrode-type water quality analyzer, a discharge valve for discharging the analyzed sample water from the electrode-type water quality analyzer, and a control means for controlling the supply valve and the discharge valve; A method of controlling a sampling device comprising:
The control means opens the supply valve and the discharge valve during unit operation of the power plant to supply sample water to the electrode-type water quality analyzer, and closes the supply valve and the discharge valve when the unit is stopped. The sample water is retained in the electrode-type water quality analyzer, and the analysis electrode of the electrode-type water quality analyzer is immersed in the sample water.
A method for controlling a sampling apparatus, characterized in that:

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