RU2427537C1 - Method of deaeration - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to heat exchange equipment and may be used fort deaeration in make-up water heating in nuclear power plant water preparation system. Proposed method consists in that nuclear power plant forced circulation and heat exchange systems are fed by chemically desalted water fed via feed water circuit into separator to be mixed therein with its boiler water. Corrosive gases are removed from make-up water by heating ahead of saturation line. For this, steam bled from separator steam circuit is used with contact in deaeration column. Deaerated water is drained from deaeration column into bypass line communicating condenser with feed water pipelined feeding water into separator. ^ EFFECT: higher efficiency and reliability of nuclear power plant. ^ 1 dwg

Description

The invention relates to a heat exchange technique and is intended to be used as a deaeration method for heating make-up water in a water treatment system of a nuclear power plant (NPP) operating on a liquid metal coolant under variable load conditions.

Known bubbling deaerator containing a tank and a deaeration column with a bubbler and a vapor transfer pipe buried in the pan, and the pipe is equipped with an annular collecting chamber with a drainage channel, the lower edge of which is placed below the water level in the tank, and the collection chamber with a drainage channel is connected to the pipe, at a distance determined from a mathematical expression from its lower edge / Kurnyk L.N. et al. Bubbling deaerator. SU. A.S. No. 1198010, С02F 1/20. Priority - 08/12/83. Publ. Bulletin of inventions No. 46. 12/15/1985 - analogue.

The disadvantage of this technical solution is the low operational values of deaeration during operation of the latter at elevated pressures, since with increasing pressure in the deaeration column, the amount of oxygen passing into the water from the gaseous to dissolved state increases, thereby creating the possibility of the deaerated tank entering the drainage channel water with a high oxygen content.

A thermal deaerator is known that contains a jet and bubbler plate placed in a column, and below it a horizontal steam perforated manifold in communication with a vertical bypass pipe integrated into the bubbler plate, the steam collector having a nozzle placed with an outlet end face with a gap relative to the lower edge of the pipe and coaxially the latter, and the diameter of the nozzle is less than the diameter of the pipe / Vikhansky G.M. et al. Thermal deaerator. SU. A.S. No. 1183778, С02F 1/20. Priority - 01/27/84. Publ. Bulletin of inventions No. 37. 10/07/1985 - prototype.

The disadvantage of this technical solution is the inefficient deaeration process when operating at elevated pressures, due to the fact that a sufficiently complete removal of carbon dioxide and oxygen from water by steam treatment of deaerated water jets does not occur due to the low-intensity heat exchange process. In addition, the uniform distribution of fluid over the nozzle is not ensured, which leads, for example, in the absence / presence / vapor space above the nozzle to reduce the effect of deaeration.

The technical result of the invention is the provision of operational reliability of nuclear power plants by effective removal of corrosive gases in the water treatment system at elevated pressures.

The specified technical result is achieved by the fact that the method of deaeration of the make-up water of the water treatment system, which consists in the fact that the make-up loop is repeatedly forced and the heat exchange system of the nuclear power plant is chemically demineralized, supplied through the feed water supply path to the separator, mixed with the boiler water of the latter, moreover, the removal of corrosive gases from make-up water is carried out by heating it to the saturation line, for this use steam selected and volume steam separator with a contact in the deaeration column, and draining water from deaerated deaeration is carried out in a column tract bypass pipeline connecting the condenser and the feedwater inlet conduit into the separator.

The essence of the invention is illustrated by the drawing, which shows a fragment of a pneumohydraulic scheme for implementing the deaeration method.

The pneumatic hydraulic circuit of the nuclear power plant provides for the presence of a separator 0, which, when implementing the deaeration method, is a container for the corresponding volume 1 of water and a supplier of dry saturated steam for the necessary manipulations of valves coming from the steam volume 2 of separator 0, as well as a condenser 3, deaeration column 4, and an electron-exchange filter 5 moreover, the deaeration column 4 and the condenser 3 are communicated by the bypass pipeline with the feed water pipe 6 supplied to the volume 1 of water of the separator 0. Fittings for real tion method for de-aeration provides the relevant functions during a given operation, nuclear power equipment. The valve 7 provides for the regulation of flow characteristics through the pipe 8 in the loop repeatedly forced circulation. The valve 9 performs in the parking mode the function of the intake of only deaerated water. The valve 10 controls the exclusion of excess steam in the deaeration column 4. Valves 11, 12, 13, 14 turn off the deaeration column 4 during normal operation of the nuclear power plant. The valve 15 directs makeup chemically demineralized water (HOW) in the parking mode from the electroion exchange filter 5 to the deaeration column 4. Valve 16 connects the electroion exchange filter 5 to operation.

The method of deaeration is as follows.

Operation in standby mode, while maintaining a nuclear power plant operating on a liquid metal coolant with the reactor power changing in the range up to the nominal value in accordance with the load of the consumer, in hot state of own heat, it becomes necessary to recharge the circuit many times by forced circulation / not shown / by a certain amount of water, but when With this recharge, corrosive gases are introduced into this circuit. The presence of copper oxide deposits on the inner surface of the evaporator pipes, which in contact with the material of the wall of the evaporator pipes, even in the absence of oxygen, cause local corrosion damage, leading to inter-circuit leakage. In the presence of oxygen, this process progresses significantly. In this connection, according to the proposed method of deaeration, the replenishing HOV with the gases dissolved in it after the electron-ion exchange filter 5 is sent to the deaeration column 4, where the corrosive gas is released and, in the form of a vapor, it is removed from further contact with the forced circulation repeatedly by supplying deaerated water through by-pass pipeline to the supply pipe 6 of the feed water into the volume 1 of the water of the separator 0. Dry saturated steam for heating the HOV and removing corrosive gas from it is fed from steam 2 of the volume of the separator 0.

The application of the proposed method of deaeration will allow for the deep removal of corrosive gases from the make-up water according to the proposed hydraulic scheme due to the significant heating upon contact of steam and make-up water in the corresponding design of the deaeration column and, as a result, reliable production of make-up water with an acceptable concentration limit of corrosive gases in it.

Claims (1)

The method of deaeration of the make-up water of the water treatment system, which consists in the fact that the make-up loop is repeatedly forced and the heat exchange system of the nuclear power plant is chemically desalinated, supplied through the feed water supply path to the separator, mixing with the boiler water of the latter, characterized in that the removal of corrosion aggressive gases from make-up water are carried out by heating it to a saturation line, for this use steam taken from the steam volume of the separator, with contact m deaeration column, and draining water from deaerated deaeration is carried out in a column tract bypass pipeline connecting the condenser and the feedwater inlet conduit into the separator.

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