Patent Application
20190346207
The present invention relates to an online temperature monitoring system and method for a direct air-cooled condenser, and in particular relates to a mobile online temperature monitoring system and method for a direct air-cooled condenser.
A direct air-cooled condenser is used to condense low-pressure steam discharged from a steam turbine so that low-pressure steam becomes condensate water. The direct air-cooled condenser mainly consists of an axial flow fan system, an A-frame support system, a condensate system, a draining system, a tube bundle system, a vacuum pumping system and a washing system. The tube bundle is made of steel parent tubes and external finned heat exchange tubes, which are arranged according to a certain rule and are welded to a tube plate at the two ends. The cross section of the parent tubes is round, elliptical or oblate. The fins are made of galvanized aluminium or galvanized steel and are attached to the parent tubes through twining, nesting, soldering or extrusion forming. Steam directly exchanges heat with air through the surfaces of metallic finned heat exchange tubes, with low-pressure steam inside the heat exchange tubes and the atmosphere outside the heat exchange tubes. Heat exchange tubes can be classified into a single-row tube system, double-row tube system, three-row tube system and four-row tube (MASH) system according to the arrangement forms. When the ambient temperature is below 0° C., since the thermal load of the heat exchange tubes is too small or is distributed unevenly and non-condensable gases exist, the heat exchange tube bundle is very easy to block up or freeze, or even the tube bundle and condensate tubes deform and freeze such that they crack during the start of the equipment or at the time of a low load, resulting in the stop of related equipment. Therefore, it is very necessary to monitor the temperature of a direct air-cooled condenser in winter so as to learn the running state of the direct air-cooled condenser and adjust the axial flow fan accordingly in time.
Currently, the following solution is usually adopted to measure the temperature of the heat exchange tube bundle of a direct air-cooled condenser: 1) A worker is assigned to perform manual patrol inspections. However, the working environment for manual patrol inspections is adverse and the labor intensity is big. Most importantly, manual patrol inspections cannot realize real-time monitoring and the worker fails to make real-time adjustments in time according to the field conditions. 2) An online temperature field monitoring system for an indirect air-cooled condenser is provided in CN205537182U, and the system comprises a plurality of monitoring cables, a plurality of collectors, a communication cable and a main controller, wherein one or more monitoring cables of the plurality of monitoring cables are respectively electrically connected to one collector of said plurality of collectors and the collectors are respectively electrically connected to the main controller with the communication cable. The plurality of monitoring cables are arranged in the outer area of the heat exchange tube bundle and the online temperature field monitoring is realized by use of a digital temperature sensor. However, since said system comprises a plurality of monitoring cables, a plurality of collectors and a communication cable, the installation and maintenance cost is high, verifications are time consuming and labour consuming. In addition, once the temperature sensor fails, it is very difficult to replace it. Furthermore, cable distribution requires large space, the heat exchange efficiency is affected if the cables are not removed in summer, and the system is not flexible because the temperature collecting points are fixed to cause blind monitoring areas.
To overcome the defects of the prior art, embodiments the present invention is intended to provide an online temperature monitoring system and method for a direct air-cooled condenser, and in particular, a mobile online temperature monitoring system and method for a direct air-cooled condenser.
According to one aspect of the present invention, an online temperature monitoring system for a direct air-cooled condenser is provided.
According to the present invention, the online temperature monitoring system for a direct air-cooled condenser comprises a temperature sensor, a temperature sensor moving system and a data processing system, and is characterized in that the temperature sensor moving system enables the temperature sensor to move on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser.
The path which said temperature sensor moving system moves along and the area which the temperature sensor scans are preset according to different arrangement forms of heat exchange tubes of the direct air-cooled condenser.
Said data processing system is connected to the temperature sensor to collect, analyse, store, and query the data collected by the temperature sensor and give an alarm based on the predefined settings.
Favorably, multi-mode control is realized according to the field configuration.
Favorably, said temperature sensor moving system comprises the nozzle assembly of the washing system of the direct air-cooled condenser.
Favorably, said temperature sensor is an infrared thermometer.
Favorably, different specifications are selected for the infrared thermometer according to the field environmental conditions.
Favorably, said temperature sensor is installed with a universal joint.
Favorably, said temperature sensor is perpendicular to the surface of the heat exchange tube bundle of the direct air-cooled condenser.
According to another aspect of the present invention, an online temperature monitoring method for a direct air-cooled condenser is provided.
According to the present invention, the online temperature monitoring method for a direct air-cooled condenser is characterized in that the method comprises: arranging a temperature sensor moving system on the surface of the heat exchange tube bundle of the direct air-cooled condenser, wherein a temperature sensor is installed on said temperature sensor moving system and the temperature sensor moves on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser; uploading the data collected by the temperature sensor to a connected data processing system, wherein said system can collect, analyse, store and query data and give an alarm based on the predefined settings.
According to a further aspect of the present invention, an application using the nozzle assembly of the washing system of a direct air-cooled condenser as a part of the temperature sensor moving system is provided and is characterized in that said temperature sensor moving system is a part of the online temperature monitoring system for the direct air-cooled condenser, and said system further comprises a temperature sensor and a data processing system, wherein at least one temperature sensor is installed on the nozzle assembly of the washing system of said direct air-cooled condenser and said temperature sensor moves on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser.
Compared with the prior art, certain embodiments of the present invention have the following advantageous effects:
1. With the online temperature monitoring system for a direct air-cooled condenser in the present invention, the temperatures in easy-to-freeze areas of a direct air-cooled condenser can favorably and continuously be monitored in real time.
2. Compared with the distribution of a plurality of monitoring cables, the present invention realizes the scanning of a plurality of monitoring points, simplifies the cable distribution, avoids any blind monitoring area, and has flexibility.
3. In the present invention, the path which the temperature sensor moving system moves along and the area which the temperature sensor scans can be preset by use of a programmable controller according to different arrangement forms of heat exchange tubes of the direct air-cooled condenser.
4. In the present invention, the programmable controller can be configured offline, and thus the path which the temperature sensor moving system moves along and the area which the temperature sensor scans can be adjusted according to the special requirements of the user to realize multi-mode control.
5. The present invention fully utilizes a washing system with basic configurations, without any new equipment investment, and in addition, it is easy to perform upgrades and transformation in the existing direct air-cooled condenser system. Thus, installation is convenient, time for installation is saved and the cost is reduced.
Further features, advantages and possible applications of the invention are apparent from the following description of working and numerical examples and from the drawings. All described and/or depicted features on their own or in any desired combination form the subject matter of the invention, irrespective of the way in which they are combined in the claims the way in which said claims refer back to one another.
The following will further describe the embodiments of the present invention by reference to the drawings. In the drawings,
The “temperature sensor” refers to a sensor which can sense a temperature and convert the temperature into an available output signal. The temperature sensor is a core part of a temperature measuring instrument. There are many types of temperature sensors. Temperature sensors are classified into two categories according to the measuring mode: contact temperature sensor and non-contact temperature sensor. A non-contact temperature sensor does not need to contact the measured medium, and the thermal radiation or convection of the measured medium is transferred to the temperature sensor to achieve the purpose of temperature measurement. Non-contact temperature sensors mainly include infrared thermometers. The environmental conditions, for example, temperature, dust, smog and steam, where infrared thermometers are located, influence both the selected specifications and the measurement accuracy.
The “temperature sensor moving system” refers to the system which is installed on the surface of the heat exchange tube bundle on the A-frame of the direct air-cooled condenser and moves on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser, for example, the nozzle assembly of the washing system of the direct air-cooled condenser.
The “data processing system” refers to a system which applies a computer to process information. Through the data information processing and organization by the data processing system, various analysis indexes are obtained from calculations and are converted into an information form which is easily accepted by people, and the processed information can be stored. The data processing system is usually a distributed control system (DCS) applied in the automatic control industry. The DCS is a multi-level computer system consisting of a process control level and a process monitoring level and linked with a communication network, and integrates 4C technologies (computer technology, communication technology, CRT (cathode-ray tube) technology and control technology). The basic idea of the DCS is decentralized control, centralized operation, hierarchical management, and flexible and convenient configuration. Thus, the functions of collecting, analysing, storing and querying data collected by the temperature sensor and giving an alarm based on the predefined settings in the present invention can be realized.
Heat exchange tubes can be classified into a single-row tube system, double-row tube system, three-row tube system and four-row tube (MASH) system according to the arrangement forms, and the arrangement form of the heat exchange tubes determines the path which the temperature sensor moves along and the area which the temperature sensor scans.
Heat exchange tubes of a direct air-cooled condenser are classified into parallel-flow tubes and counter-flow tubes. A heat exchange tube is a parallel-flow tube if the flowing directions of steam and condensate water in the heat exchange tube are the same, and is a counter-flow tube if the flowing directions of steam and condensate water in the heat exchange tube are opposite. Most steam condenses in parallel-flow tubes, and steam in the counter-flow tube bundle condenses by flowing in an opposite direction, that is to say, remaining steam and non-condensable gases flow from the bottom to the top in the counter-flow tubes. During this process, some condensate water is still produced and flows downward. Parallel-flow tubes and counter-flow tubes are connected with a bottom condensate water tank to balance the pressure between the two sides and the steam side. A vacuum pumping tube bundle is arranged on the top of the counter-flow tubes to pump out non-condensable gases and maintain the vacuum state in the air-cooled condenser. Parallel-flow tubes and counter-flow tubes can be arranged separately or can be arranged uniformly together.
The arrangement forms of parallel-flow tubes and counter-flow tubes are classified into four types: the first type is the four-row tube (MASH) system which consists of three rows of inner parallel-flow tubes near the A-frame and one row of the outermost counter-flow tubes, the second type is the single-row arrangement of large-diameter flat steel soldered with aluminium wave-finned tubes or flat steel tubes hot dip galvanized with steel fins, the third type is the double-row arrangement of large-diameter hot dip galvanized elliptical steel tubes covered with rectangular steel fins, and the fourth type is the three-row arrangement of large-diameter hot dip galvanized elliptical steel tubes surrounded by elliptical finned tubes.
Among the four arrangement forms, for the single-row tube system, the double-row tube system and the three-row tube system, parallel-flow tubes and counter-flow tubes are separately arranged, that is to say, parallel-flow tubes and counter-flow tubes are distributed in different areas on the whole surface of the heat exchange tube bundle, and for the four-row tube (MASH) system, parallel-flow tubes and counter-flow tubes are arranged uniformly together, that is to say, the three rows of inner parallel-flow tubes near the A-frame and one row of the outermost counter-flow tubes are arranged across the whole surface of the heat exchange tube bundle. Since the steam flow in parallel tubes is adequate but the steam in the following counter-flow tubes is small in winter, the counter-flow tube bundle freezes easily. Therefore, the temperatures of counter-flow tubes need to be mainly monitored online in the present invention. For a single-row tube system, a double-row tube system and a three-row tube system, counter-flow tubes are separately arranged in some areas of the heat exchange tube bundle (
In addition, for the above-mentioned four arrangement forms, the parent tubes are uniformly arranged at an equal distance in the extension direction of the A-frame. To ensure that each column of parent tubes in the scanning area on the surface of the heat exchange tube bundle can be scanned, the distance the temperature sensor moving system moves is set to the distance between parent tubes in advance. The distance between parent tubes varies with the arrangement forms of heat exchange tubes.
“Multi-mode control realization according to the field configuration” means that the programmable controller is configured offline to adjust the path which the temperature sensor moving system moves along and the area the temperature sensor scans according to the special requirements of the user to realize multi-mode control. For example, the single-row tube system, double-row tube system or three-row tube system can be scanned across the whole surface of the heat exchange tube bundle according to the requirements of the user.
After the heat exchange tube bundle of the direct air-cooled condenser runs for a period of time, dust with strong adhesive force deposits on the surface of the fins. Dust reduces the heat exchange capability of the heat exchange tube bundle and directly affects the operation of the steam turbine. Therefore, the heat exchange tube bundle must be cleaned regularly. For this reason, the washing system is a basic configuration of the air-cooled condenser and the heat exchange tube bundle is washed by pressurized water sprayed out of the nozzle of the nozzle assembly of the washing system.
When the ambient temperature is below 0° C. in winter, the heat exchange tube bundle is freezes very easily. In this case, the washing system does not work. Therefore, it is very necessary to monitor the temperature of a direct air-cooled condenser in winter so as to learn the running state of the direct air-cooled condenser and adjust the axial flow fan accordingly in time. However, the present solution can enable the nozzle assembly of the washing system to move on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser. Thus, after a temperature sensor is installed on said nozzle assembly, the temperature sensor can move on the plane parallel to the heat exchange tube bundle of the direct air-cooled condenser to collect data.
In a programmable controller system, the buttons and travel switches serve as input signal elements of the programmable controller, and the contactors serve as output actuators to control the forward rotation, backward rotation, stalling, and the running time of the horizontal drive mechanism which moves laterally and the lifting drive mechanism which moves longitudinally. The mobile washing platform can automatically stop when it travels to the left or right stop point to touch the travel switch 9 or travels to the upper or lower stop point to touch the travel switch 10.
When fully automatic control starts, the position of the mobile washing platform is adjusted to keep the temperature sensor located just above the central line of the rightmost parent tube and the nozzle assembly located at the lower stop point; then the nozzle assembly moves 1000 mm upward, the mobile washing platform moves 95 mm left, and here the distance A between parent tubes of the four-row tube system is 95 mm; then the nozzle assembly moves 1000 mm downward, and the mobile washing platform moves 95 mm left; this process is repeated until the mobile washing platform returns to the original position after moving to the left stop point. A scan is performed every 10 minutes or so. If you want to manually stop the system during the operation, you can press the PAUSE button and choose to maintain the current position or return to the original position.
When fully automatic control starts, the position of the mobile washing platform is adjusted to keep the temperature sensor located just above the central line of the rightmost parent tube and the nozzle assembly located at the lower stop point; then the nozzle assembly moves 1000 mm upward and the mobile washing platform moves 58 mm left, and here the distance B between parent tubes of a single-row tube system, for example, is 58 mm; then the nozzle assembly moves 1000 mm downward and the mobile washing platform moves 58 mm left; this process is repeated until the mobile washing platform returns to the original position after moving to the left stop point. A scan is performed every 5 minutes or so. If you want to manually stop the system during the operation, you can press the PAUSE button and choose to maintain the current position or return to the original position.
As a further embodiment, the programmable controller can be configured offline to adjust the path which the temperature sensor moving system moves along and the area the temperature sensor scans according to the special requirements of the user. For example, the single-row tube system, double-row tube system or three-row tube system can be scanned across the whole surface of the heat exchange tube bundle according to the requirements of the user.
For the above-mentioned embodiments, when the acquired temperature is below 20° C., an alarm will be triggered and the data processing system will record the first appearance. The first appearance refers to the first alarm signal which appears when an accident trip happens. This signal is very important to the analysis of the accident cause and can basically be considered as the major cause for an equipment protection action. Thus, the running state of the direct air-cooled condenser can be learned in time and the axial flow fan can be adjusted accordingly.
Although the nozzle assembly of the washing system of the direct air-cooled condenser is used as a part of the temperature sensor moving system in the above-mentioned description, those skilled in the art can appreciate that the present invention also applies to any apparent modification made without departing from the conception of the present invention, for example, the addition of an extra temperature sensor moving system to realize the function of moving the temperature sensor on a plane parallel to the surface of the heat exchange tube bundle of the direct air-cooled condenser.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.
The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.
“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.
Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.
All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.
This application is a § 371 of International PCT Application PCT/CN2016/113394, filed Dec. 30, 2016, which is herein incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2016/113394 | 12/30/2016 | WO | 00 |
