SU1714290A1 - Method of operation of horizontal steam generator - Google Patents

Abstract

The invention relates to a power system and can be used in steam generators of nuclear power plants with water reactors. The purpose of the invention is to increase the reliability of the steam generator by reducing the concentration of soluble substances in the feed water and reducing the unevenness of the steam load. In the method, the heating medium is supplied to the collector 6. It enters the pipes of the beam 3 and is discharged from the steam generator through the collector 7. In the annular space of the beam 3, steam is generated. The feed water is supplied to the distribution manifolds 10, while in the zone supplying the heating medium is fed in an amount of 10-40% higher than the amount of steam generated in this zone. 5 ill. / L — n ^ Phi ^}. ^^^ 0 ^ 1 ^ hO × > & O > &

Description

The invention relates to a power system and can be used in steam generators of nuclear power plants with water and water reactors.

A known method of operating a horizontal steam generator with a U-shaped tube bundle consists in supplying a heating medium to the said bundle and distributing feed water over different zones of its surface. A special feature of the operation of steam generators of this type is the uneven concentration of soluble substances in its water volume and a substantial unevenness steam load. In fact, the volume of the steam generator is divided by the supports and the spacer elements of the tube bundle into separate zones, purging is carried out from zones located approximately in the middle of each half of the cylindrical part of the body, as well as from water pockets of the heating medium collectors.

Based on the test results of steam generators and a calculation analysis of the uneven steam load and salt balance in the indicated source, it was shown that the salt content in the supply zones of the heating medium and near the end of the steam generator closest to the collector of the heating medium can be significantly higher than the average. This circumstance can lead to a decrease in the reliability of the heating surface.

The aim of the invention is to increase the reliability of the steam generator by reducing the concentration of soluble substances in the feed water and reducing the unevenness of the steam load.

This goal is achieved by supplying feed water to the supply zone of the heating medium in an amount that is 10-40% higher than the amount of steam generated in this zone.

FIG. 1 schematically shows a structural diagram of a steam generator that implements this method: in FIG. 2 shows the calculated dependence of the change in steam velocity along the length of the steam generator; in fig. 3 the calculated dependence of the salt content in the water volume of the true steam generator; in fig. 4 — tentative curves of the change in the relative steam velocity in the zone for supplying the heating medium and in the zone of the steam generator when the relative feedwater flow rate changes in the zone for supplying the heating medium; in fig. 5 Dependence of the relative salt content of the steam generator water in the supply zone

heating medium from the relative consumption of feed water in this area.

The method of operating a horizontal steam generator with an I-shaped tube bundle consists in supplying a heating medium to the said bundle, distributing feed water over different zones of its surface, and supplying feed water to the heating supply zone in an amount exceeding the amount of steam generated in this zone.

The steam generator consists of a cylindrical horizontal housing 1 with bottoms

2. Inside the case a bundle of 3 horizontally arranged U-shaped

pipes. The bundle 3 is divided into separate packages 4, between which there are drop gaps

5. Bundle pipes Z connected to the collector 6 for supplying the heating medium and (collector 7

0 removal of the heating medium, located vertically. A submerged perforated sheet 8 is installed above the beam 3, and a louver drier 9 is placed in the napOBON space of the housing 1. Between the beam 3 and sheet 8

5, distribution water supply manifolds 10 are installed, connected to the feed water naTpy6j OM 11. On the lower generatrix of the housing 1 are installed fittings 12 purging the steam generator. In order to ensure a given distribution of feedwater flow to individual zones of a paeogenerator, control valves can be installed at the inlet to each collector or calculated by

5 ratios of the washers, the collectors 10 may have a different number of holes or may be located with y, the pitch magnitude between them relative to the collectors 6. The fittings 12 are most expediently located on the housing 1 near the bottoms 2.

The method of operation of the steam generator is as follows.

The heating medium is supplied to the collector.

6. enters the tube beam 3 and is removed from the 5 steam generator through the manifold 7. Due to

the heat given off by the heating medium in the annular space of the beam 3 steam is generated. The feed water is fed through pipe 11 to the dispensing manifolds 10. When

At the same time, feedwater is supplied to the zone for supplying the heating medium (collector zone) by 10–40% more than the amount of steam generated in this zone, while in the remaining zones feedwater is supplied

5 is proportional to the amount of steam generated in these zones. PVTA water condenses a portion of the vapor exiting the beam.

3. The vapor enters under the submerged perforated sheet 8, passes through the evaporation mirror and separates in the steam space of the housing 1. The final drying of the steam occurs in the louvered dryer 9. Water of the steam generator circulates inside the housing, dropping in the gaps 5 between the packages A of the pipe puyka 3 the steam generator is discharged to the purge through fittings 12.

FIG. Figures 2 and 3 present the results of a specific application of the proposed method.

Curve 1 in FIG. 2 corresponds to the speed of steam at the exit of the tube bundle; curve 2 reveals a known method of operation of the steam generator with a uniform supply of feed water, and curve 3 describes the proposed method of operation. Comparing curves 3 and 2, it can be verified that this method of feeding water leads to a noticeable equalization of the steam load. Important is a significant reduction in the maximum steam velocity in the zone of supply of the heating medium (by more than 20%). At the same time, the steam velocity in the end zones of the steam generator slightly increases, but remains less than 0.5 m / s.

Curve 1 in FIG. 3 corresponds to the known method of operation of the steam generator and is obtained from the above balance dependencies. When feeding the feed water according to the proposed method of operation (curve 2), the salt content in the zone for supplying the heating medium and in the zone of the end face closest to the inlet manifold of the heating medium is significantly reduced (more than 2 times).

The relative steam velocity and relative salinity in the supply zone of the heating medium (Figures 4 and 5) sharply decrease the exaggeration of the feedwater supply to this zone from 1.0 to 1.1. It is this circumstance, as well as the conditions for permissible increase in salt concentration, that determine the minimum increase in feedwater consumption by 10% more than the amount of steam generated in the zone of supply of the heating medium.

Claims (1)

A further increase in feedwater flow to this zone contributes to a slight decrease in steam velocity and salinity, however, the dependence becomes flat and reaches 1 when the feedwater flow exceeds 40% more than the amount of steam generated in this zone. At the same time, if the indicated flow rate is exceeded, it starts to exceed 1 relative speed in the area of the end of the steam generator closest to the collector to supply the heating medium. The latter indicates an increase in non-uniformity in the steam load along the length of the steam generator with an increase in feed water flow by more than 40% higher than the steam flow in the zone of supply of the heating medium. Claims of Invention A method of operating a horizontal steam generator with an I-shaped tube bundle, consisting in supplying a heating medium to the beam, distributing feed water over the supply and removal zones of the heating medium, to one of which water is supplied in an amount. Exceeds the amount of steam generated in this zone, c tl and h ay; u and with that. In order to increase the reliability of the steam generator by reducing the concentration of soluble substances in the feed water and reducing the unevenness of the steam load, water is supplied to the supply zone of the heating medium in an amount 10–40% higher than the amount of steam generated in this zone. V.