SU1760999A3 - Air-cooled steam condenser control device - Google Patents

Abstract

Usage: in installations for air condensation of steam, in particular exhaust steam of power plant turbines. SUMMARY OF THE INVENTION: A device for controlling air-cooled steam condensers 1 having rows of tubes connected in parallel to steam and condensate with screens 8 that change the cooling surface, contains means for measuring temperatures of steam, ambient air and condensate, adjustors 12 of the screens 8 and comparator Additional means for measuring the temperature of the condensate are installed on the lower portion of one of the subsequent rows of pipes, preferably the second row, and connected to a comparator connected to the outlet with regulators 12. When the pipes are positioned with the formation of an opening 15 between them, the device is equipped flaps 16 with regulators 17, their positions with means 9 connected to the latter for measuring the temperature of the steam. 3 hp f-ly, 3 ill.

Description

The invention relates to installations for the air condensation of steam, in particular steam turbine power plants.

In the known designs of air-cooled condensers, undesirable supercooling of steam is possible. This leads to thermodynamic losses and may cause a danger of freezing at low ambient temperatures, resulting in damage to the pipes. Various measures have been proposed to eliminate the possibility of freezing of water in condensers.

The simplest way to prevent freezing is partial condensation of the vapor. as described in US Pat. U.S. Pat. No. 3,705,621. Obviously, this does not fully utilize the performance of capacitors. It is possible to control the temperature of the condensate flowing from the first row of pipes. If this temperature becomes lower than a certain value, then cooling is reduced, for example, by changing the operation of the fan (US Pat. No. 4,177,859). Instead of controlling the operation of the fan, it is possible to use throttling and recirculation of the air flow rather than reducing it. For this purpose, blinds suitable for shielding air condensers are used, the degree of shielding depending on the temperature of the condensate, the environment and the incoming steam. As a result of recirculation, the cooling tubes of the first row are blown with relatively warmer air. Such an air condensation unit is described in US Pat. US No. 4450899 (prototype). However, this device does not allow

prevent hypothermia in an economical way.

The object of the present invention is to increase the efficiency and reliability of air-cooled condensers by preventing overcooling of the condensate.

The basic idea of the invention is based on the fact that undercooling can be detected by comparing the temperatures of condensates flowing from the first and subsequent rows of pipes, preferably from the first and second rows. When the unit is operating under the specified operating conditions, the specified temperature difference is zero. Under conditions of uneven load, for example, due to differences in the parameters of the fans, subcooling is possible and temperature differences occur. The equalization of parameters occurs under the action of regulators, which are affected by the signal from thermocouples.

The purpose of the invention is achieved by the fact that a device for regulating air-cooled steam condensers having at least two rows of pipes, connected in parallel by steam and condensate, with screens that change the cooling surface of the latter, containing means for measuring the temperature of the steam, approx. - Cutting air and condensate, and the positioners of the screens, additionally equipped with a comparator, and means for measuring the temperature of the condensate are installed on the lower portion of one of the following r dbv pipes, preferably of the second row, and are connected to a comparator connected by an output with a screen position adjuster. When U-shaped placement of cooling tubes and the presence of an opening between them for air recirculation, the device can be equipped with dampers with regulators of their position and means for measuring steam temperature are connected to the latter. The device can be equipped with dampers for changing the supply and removal of cooling air with their position controllers, to which means for measuring the temperature of the cooling air are connected. The controls for the position of the screens and the controls for the position of the shutters can be equipped with manual control means.

Figure 1 shows schematically the structure of the device with the U-shaped arrangement of the cooling tubes; figure 2 presents the element of the capacitor; FIG. 3 shows a device design with additional regulators.

A device for controlling air-cooled condensers 1 contains several rows of pipes (for example 2, 3 and 4 in Fig. 2), connected in parallel with a pair and a condensate. This inclusion is achieved by installing steam collectors 5 with appropriate steam supply pipes 6 and collecting chambers 7. The pipes are provided with screens 8 that change the cooling surface. The device comprises means 9 for measuring the vapor temperature, means 10 for measuring the ambient air temperature and means 11 for measuring the temperature of the condensate. The device is equipped with regulators 12 of the position of the screens. Additional means 13 for measuring the temperature of the condensate are mounted on the lower portion of one of the subsequent rows of pipes, preferably the second row, and connected together with the means 11 to a comparator 14 connected by an outlet to the regulator 12 of the position of the screens.

When U-shaped placement of pipes between the capacitors 1, an opening 15 is made. In said opening 15, valves 16 are installed with their positioners 17, to which means 9 for measuring the steam temperature are connected. The adjustment can be carried out using a comparator 18 connected by a line 19 to the regulators 17, which receives a signal from the means 9 for measuring steam temperatures and is compared with the value set by the manual regulator 20.

Air-cooled condensers 1 are installed in the housing 21 connected in the upper part with the condensers. In the lower part of the casing 21, inlet ports 22 are made, by means of which air is supplied to the inlet of fans 23 installed in openings 24. The device can be equipped with shutters 25 for changing the cooling air supply with their position adjusters 26, to which means 10 are connected ambient temperature. These dampers can be installed in the upper part of the casing 21 at the air outlet, as well as in the inlet windows 22. Regulation can be carried out using a comparator 27 connected by lines 28 to regulators 26, which receive a signal from means 10 for measuring ambient temperature air and compared with the value set by hand-held device 29,

The threshold value of the temperature difference, as measured by means 11 and 13, is set using the manual controller 30.

The proposed device has in normal operation three regulatory systems. The first system serves to prevent overcooling by means of screens 8, regulators 12, comparator 14 with means for measuring temperature (thermometers) 11, 13 and manual regulator 30, It works as follows: signals from thermometers 11 and 13 enter comparator 14, which captures the difference signal. If it exceeds the threshold value set by the manual controller 30, the comparator 14 outputs an output signal to the controller 12, which drives the screen 8 until the difference signal equals the threshold value.

The second system is responsible for the temperature level and includes dampers 16c with regulator 17, line 19, comparator 18, means (thermometers) 9 for measuring the temperature of steam and manual regulator 20. It works as follows. The readings of the thermometer 9 are compared in the comparator 18 with two threshold values set manually by the controller 20. Depending on the comparison results, the controller 17 acts on the position of the valves 16.

The third system, which includes a means for measuring temperature (thermometer) 10, a handheld device 29, a comparator 27, regulators 26, lines 28 and dampers 25, makes it possible to start the installation for air condensation — at a very cold ambient temperature without danger of freezing.

It is assumed that the working surface of the pipes provides complete condensation without supercooling at a steam temperature of 50 ° C and an ambient temperature of 20 ° C. Exhaust steam enters through pipelines 6 to collectors 5 and further to pipes 2, 3, 4 of air condensers 1. Fans 23 supply air in the direction indicated by arrows 31. If there is a temperature difference between thermometers 11 and

13 and it is less than the threshold value, there is no subcooling. If the difference is higher than the threshold value, then there is supercooling and a comparator

14 generates a signal to the regulator 12, causing the screen 8 to move in the direction of closing the cooling surfaces, thereby eliminating the condensate overcooling.

To adapt to the temperature level of steam, the previously described second system serves, which accordingly opens

or closes the shutters 16 as the temperature level rises or falls.

When starting the system in a very cold season, the lower inlet flaps and the top exhaust flaps 25 are controlled by a comparator 27, these flaps being closed, and air is circulated in the direction of the arrows 32. After its warming up, the slider 25 begins to open gradually and working conditions of cooling.

The technical solution eliminates asymmetry in the distribution of loads by measuring between the capacitors and the collecting chamber and changing the cooling surface depending on these measurements. At the same time, the working length of the surfaces should be changed only by 20-40%, which provides cost savings.

Claims (4)

1.Device for adjusting the air-cooled steam condensers, particularly turbine steam 5 power plants with at least two rows of pipes connected in parallel with steam and condensate with screens that change the cooling surface of the latter, containing means for measuring 0 steam temperature, ambient air and condensate v, screen position controllers, characterized in that, in order to increase efficiency and reliability by preventing the condensate from being heated, the device further comprises a comparator, and means for measuring the temperature of the condensate are installed on the lower portion of one of the subsequent pipe rows, preferably 0 of the second row, and are connected to a comparator connected by an output with screen position controllers. 2. The device according to claim 1, about tl and h and y sh e with the fact that with a U-shaped placement 5 cooling tubes and an opening between them for recirculation of air, it is equipped with dampers with their position controllers, and means for measuring the steam temperature are connected to the latter. 0 3. A device according to claims 1 and 2, characterized by & in that it is provided with dampers for changing the supply and removal of cooling air with their position controllers, to which means for changing the ambient air temperature are connected. 4. A device according to claims 1-3, characterized in that the position controllers of the screens and the position controllers of the valves are provided with manual control means. yff /// /// /// w /// /// /// /// / JF /// /// /// /// /// /// /// /// /// /// Schi 2. x-tf Yu figs