Temperature control method for air-cooled condenser

Abstract

The invention discloses a temperature control method for an air-cooled condenser, and belongs to the field of condenser antifreeze. The temperature control method of the invention, according to the influence of ambient wind on the heat dissipation of air-cooled condensers at different positions around the tower, when the temperature of the condensate water pipe is lower than the set value, the air regulating devices of several cooling triangle units distributed on the 1 / 6 to 1 / 8 circumference of the windward surface and the circumference symmetrical to the center thereof are gradually closed, and then the steam inlet pipe valves of these cooling triangles are closed, so that the condensate water temperature can be quickly increased, the heat dissipation of the heat dissipation unit can be balanced, and the risk of freezing can be reduced; when the temperature of the condensate water pipe of the air-cooled condenser is higher than the set value, the steam inlet pipe valves of a group of cooling triangle units distributed on the windward surface and the circumference symmetrical to the center thereof are opened one by one, and then the opening of the air regulating device corresponding to the cooling triangle is gradually increased until all cooling triangles are put into operation according to the above steps or the temperature of the condensate water pipe is lower than the set value, so that the condensate water temperature is steadily reduced.

Description

Technical Field

[0001] The invention belongs to the field of condenser antifreeze, in particular to a temperature control method for an air-cooled condenser. Background Art

[0002] In the natural ventilation direct air cooling system, the exhaust steam of the steam turbine is sent to the air condenser through the exhaust pipe. The air condenser is arranged vertically at the air inlet of the natural ventilation air cooling tower. The suction force of the tower is used to make the cold air flow through the condenser surface, so that the steam in the condenser is condensed. One of the main factors affecting the operation of the air cooling system in winter is that when there is strong wind, the air condenser does not have a large amount of water volume buffer, which causes the condenser tube bundle to freeze and block quickly, causing the condenser fin tube to deform or freeze and crack, causing permanent damage. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcoming that an air-cooled condenser in an existing natural ventilation direct air cooling system is prone to freezing and cracking, and to provide a temperature control method for an air-cooled condenser.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A temperature control method for an air-cooled condenser comprises the following operations:

[0006] When the cooling triangle units on the air-cooled condenser are operating normally, if the condensate pipe temperature of the air-cooled condenser is lower than the set value, the air regulating devices and steam inlet pipe valves of several cooling triangle units on the windward and leeward sides are closed;

[0007] When the air regulating device and the steam inlet pipe valve of the cooling triangle unit on the windward side and the leeward side of the air-to-air condenser are in the closed state, if the temperature of the condensate pipe of the air-to-air condenser is higher than the set value, the air regulating device and the steam inlet pipe valve of the cooling triangle unit on the windward side and the leeward side are opened.

[0008] Furthermore, when several cooling triangle units on the air-cooled condenser are distributed on a circle and the cooling triangle units on the air-cooled condenser are operating normally, if the condensate water pipe temperature of the air-cooled condenser is lower than the set value, the air regulating devices of several cooling triangle units distributed on 1 / 6 to 1 / 8 of the circumference of the windward side and on the circle symmetrical with its center are gradually closed.

[0009] Furthermore, after closing the air regulating device, if the condensate pipe temperature of the air-cooled condenser is still lower than the set value, the corresponding steam inlet pipe valve of the closed air regulating device will be closed, and the corresponding cooling triangle unit will be shut down.

[0010] Furthermore, when several cooling triangle units on the air-cooled condenser are distributed on a circle, and the air regulating devices and steam inlet pipe valves of the cooling triangle units on the windward and leeward sides of the air-cooled condenser are in a closed state, if the temperature of the condensate water pipe of the air-cooled condenser is higher than the set value, several groups of cooling triangle units distributed on 1 / 6 to 1 / 8 of the circumference of the windward side and on the circle symmetrical with its center are opened one by one until all the cooling triangle units are put into operation or the temperature of the condensate water pipe of the air-cooled condenser is lower than the set value.

[0011] Furthermore, when opening the cooling triangle unit, the steam inlet valve is opened first, and then the opening of the corresponding air regulating device is gradually increased, and the windward side and a group of cooling triangle units symmetrical to the center are opened synchronously, and then the next group is opened. Compared with the prior art, the present invention has the following beneficial effects:

[0012] The temperature control method of the air-cooled condenser of the present invention is based on the influence of the ambient wind on the heat dissipation of the air-cooled condenser at different positions around the tower. When the condensate pipe temperature of the air-cooled condenser is lower than the set value, the air regulating devices and steam inlet pipe valves of several cooling triangle units distributed on 1 / 6 to 1 / 8 of the circumference of the windward side and on the circumference symmetrical to the center thereof are gradually closed, so that the condensate temperature can be quickly increased, the heat dissipation of the heat dissipation units can be balanced, the risk of freezing can be reduced, and the control sequence can be simplified. If the cooling triangle units are closed one by one, the reaction time is delayed, the cooling triangle on the windward side is out of operation, and the cooling triangle unit on the leeward side bears too much heat dissipation. Heat increases the risk of freezing; when the temperature of the condensate pipe of the air-cooled condenser is higher than the set value, open the steam inlet pipe valves of a group of cooling triangle units distributed on the windward side and on the circumference symmetrical to its center one by one, and then gradually increase the opening of the air regulating device corresponding to the cooling triangle according to the increase in the condensate temperature, until all cooling triangles are put into operation according to the above steps or the condensate pipe temperature of the air-cooled condenser is lower than the set value; this control method can steadily reduce the condensate temperature and avoid frequent switching of the cooling triangle on and off caused by the condensate temperature of too many cooling triangle units put into operation at the same time suddenly dropping below the set value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Provides a heat dissipation distribution diagram for each cooling triangle when the valve is fully open and under strong ambient wind;

[0014] Figure 2 This is a comparison chart of heat dissipation when the windward cooling triangle is withdrawn or fully opened under the influence of strong wind;

[0015] Figure 3 This is a comparison chart of the heat dissipation when the cooling triangle on the leeward side is withdrawn or fully opened under the influence of strong environmental wind;

[0016] Figure 4This is a comparison chart of the heat dissipation when the cooling triangles on the leeward side and the windward side are closed or fully opened under the influence of strong winds;

[0017] Figure 5 for Figure 1-Figure 4 Comparison chart of data;

[0018] Figure 6 Schematic diagram of the structure of the device in the embodiment of the present invention.

[0019] Among them: 1-natural ventilation cooling tower; 2-air condenser; 3-water pump; 4-air regulating device; 5-steam inlet pipe; 6-valve; 7-condensate pipe; 8-condensate main pipe; 9-water tank. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0023] See also Figure 6 , Figure 6 It is a schematic diagram of the structure of the device in an embodiment of the present invention, including an air-cooled condenser 2 arranged around the air inlet of a natural ventilation cooling tower 1, two air-cooled condensers 2 and an air regulating device 4 form a plurality of cooling triangle units, and the air regulating device 4 is arranged on the windward side; a valve 6 is provided on the steam inlet pipe 5 of the cooling triangle unit, and the condensate pipe 7 of the cooling triangle unit is collected in a condensate main pipe 8, and a water tank 9 is provided on the condensate main pipe 8. The water in the water tank 9 is pressurized by a water pump 3 and returned to the thermal system.

[0024] The system's workflow is:

[0025] The steam enters the corresponding air-cooled condenser 2 through the steam inlet pipe 5. The wind outside the air-cooled condenser 2 takes away the heat of the steam inside. The steam condenses into water in the air-cooled condenser 2. The condensed water passes through the condensed water pipe 7 and is collected in the condensed water main pipe 8. Then, the condensed water enters the water tank 9. When the water pump 10 is turned on, the water in the water tank 9 is pressurized by the water pump 10 and returned to the thermal system.

[0026] The wind speed outside the air-cooled condenser 2 is controlled by the air regulating device 4. When the air regulating device 4 is closed, the wind speed outside the air-cooled condenser 2 is minimum, and when it is opened, the wind speed is maximum.

[0027] The valves on the steam inlet pipe of the cooling triangle unit can also be partially installed, and it is not required to be installed on every steam inlet pipe.

[0028] The antifreeze system can be controlled automatically or it can be activated after manual confirmation based on the alarm signal of the condensate temperature set value.

[0029] The present invention studies the influence of opening the cooling triangle on the natural ventilation air-cooled condenser in the presence of wind through numerical simulation experiments. Under extremely low temperatures, part of the cooling triangle is shut down by closing the air regulating device and the steam inlet pipe valve to ensure the antifreeze requirements of the entire system.

[0030] See also Figure 1 , Figure 1 For each cooling triangle, the heat dissipation distribution diagram is shown in the state of fully open valve and strong wind. Figure 1 It can be seen that under the influence of strong wind, the heat dissipation of each cooling triangle is very uneven, ranging from -45% to 167% based on the average heat dissipation of each cooling triangle. Among them, the heat dissipation of the five cooling triangles on the windward side is more than 1.55 times the average value, with strong heat dissipation capacity and a very high risk of freezing. The heat dissipation of the five cooling triangles on the leeward side, which is symmetrical to the windward side, is 1.05 to 1.2 times the average value, with strong heat dissipation capacity. The heat dissipation of the cooling triangles on the other two sides is relatively low, with the lowest being only 45% of the average value.

[0031] See also Figure 2 , Figure 2 This is a comparison chart of the heat dissipation when the windward cooling triangle is closed or fully opened under the influence of strong wind. Figure 2 It can be seen from the figure that only the five cooling triangles on the windward side are out of operation, that is, Figure 6The heat dissipation of the cooling triangles 13 to 17 on the leeward side (32 to 36) has increased significantly. The heat dissipation of cooling triangle 35 has increased the most, reaching 1.45 times the average value, which is close to the heat dissipation of the cooling triangles on the windward side. The maximum heat dissipation of the remaining cooling triangles is about 1.55 times the average value, with a large heat dissipation capacity, and the risk of freezing is still very high. The remaining cooling triangles whose original heat dissipation was lower than the average value have not increased much, and the cooling triangle with the smallest heat dissipation has only increased to ~55%, which has not significantly improved the balance of the heat dissipation of the cooling triangles.

[0032] See also Figure 3 , Figure 3 This is a comparison of the heat dissipation when the cooling triangle on the leeward side is closed or fully opened and under the influence of strong wind. Figure 3 It can be seen that if only the five cooling triangles (32-36) on the leeward side are withdrawn, the heat dissipation of the cooling triangle on the windward side remains almost unchanged, still as high as 167%, and the cooling triangle with the smallest heat dissipation is only increased to ~50% of the average value, without any improvement in antifreeze.

[0033] See also Figure 4 , Figure 4 This is a comparison of the heat dissipation when the cooling triangle on the leeward side and the windward side is closed or fully opened under the influence of strong wind. Figure 4 It can be seen that when the five cooling triangles on the windward side (13-17) and the leeward side (32-36) are withdrawn together, the heat dissipation of other cooling triangles increases, so that the heat dissipation of each operating cooling triangle is relatively balanced, varying between 65% and 150%, and the antifreeze effect is significant.

[0034] Figure 5 This is a comparison chart of the above four situations. It is necessary to monitor and adjust the operation of the leeward cooling triangle after the windward cooling triangle is shut down. When strong winds occur, the air regulating devices and steam inlet pipe valves of multiple cooling triangle units on 1 / 6 to 1 / 8 of the circumference and 1 / 6 to 1 / 8 of the circumference on the central symmetric side are closed continuously. The air regulating devices are closed first, and then the steam inlet pipe valves are closed to achieve the purpose of shutting down the corresponding cooling triangle. When the strong winds disappear, the air regulating devices and steam inlet pipe valves of a group of two centrally symmetric cooling triangle units are opened one by one. The steam inlet pipe valves are fully opened, and then the air regulating devices are gradually opened.

[0035] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A temperature control method for an air-cooled condenser, characterized in that: The following operations are included: When several cooling triangle units on the air-cooled condenser are distributed on a circle and all the cooling triangle units on the air-cooled condenser are operating normally, if the condensate pipe temperature of the air-cooled condenser is lower than the set value, the air regulating devices of several cooling triangle units distributed on the 1 / 6~1 / 8 circumference of the windward side and the circumference symmetrical to the center thereof are gradually closed; after closing the air regulating devices, if the condensate pipe temperature of the air-cooled condenser is still lower than the set value, the steam inlet pipe valve corresponding to the closed air regulating device is closed, and the corresponding cooling triangle unit is shut down; When several cooling triangle units on the air-cooled condenser are distributed on a circle, and the air regulating devices and steam inlet pipe valves of the cooling triangle units on the windward and leeward sides of the air-cooled condenser are in a closed state, if the temperature of the condensate pipe of the air-cooled condenser is higher than the set value, several groups of cooling triangle units distributed on 1 / 6~1 / 8 of the circumference of the windward side and on the circle symmetrical with its center are opened one by one until all the cooling triangle units are put into operation or the condensate pipe temperature of the air-cooled condenser is lower than the set value; when opening the cooling triangle unit, open the steam inlet pipe valve first, and then gradually increase the opening of the corresponding air regulating device, and a group of cooling triangle units on the windward side and symmetrical with its center are opened synchronously, and then the next group is opened.

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