RU2214558C1 - Drum boiler operation method - Google Patents

Abstract

FIELD: steam generation, possibly heat power stations and boiler aggregates. SUBSTANCE: method of drum boiler operation comprises steps of generating saturated steam by evaporation of boiler water and discharging it through steam duct; realizing continuous blow-through from last stage of boiler water evaporation at regulating flowrate of blow-through water according to salt content of saturated steam. EFFECT: enhanced operational reliability and efficiency of drum boiler. 1 dwg

Description

 The invention relates to the field of power engineering and can be used in thermal power plants and boiler plants.

 A known analogue is the method of operation of a drum boiler (see Delyagin G.N., Lebedev V.I., Permyakov B.A. Heat-generating installations: Textbook for high schools.-M .: Stroyizdat, 1986. P. 358), according to which saturated steam is obtained by evaporating the boiler water and is discharged through the steam line, continuous purging is carried out from the last stage of boiler water evaporation. This analogue is taken as a prototype.

 The reason that impedes the achievement of the technical result indicated below when using the known method adopted for the prototype is that in the known method of operation of the drum boiler, the amount of purge water removed from the last evaporation stage is constant and depends only on the pressure in the boiler and its steam capacity. During the operation of the boiler, the quality of the saturated steam generated by it can change. With a decrease in the quality of saturated steam generated by the boiler or an increase in its salt content from the standard value, scale is intensively deposited on the inner surface of the pipes of the superheater and heat exchangers. The reduced quality of the saturated steam generated by the boiler indicates an increased salt content of the boiler water, moving along the circulation circuits of the drum boiler, which in turn leads to an acceleration of the formation of deposits on the inner surfaces of the heating of the drum boiler, disruption of its normal operation and intensive corrosion processes, which can short time to disable equipment. In addition, when the salt content of the saturated steam generated by the boiler is lower than the standard value, which indicates a lower salt content of the boiler water, the removal of a constant amount of purge water from the last evaporation stage leads to an increase in the loss of the mass of boiler water and the heat contained in it, which reduces the efficiency of the drum boiler .

 The technical result of the claimed solution is to increase the reliability and efficiency of the drum boiler.

 The invention consists in the following.

 To increase the reliability and efficiency of the drum boiler operation, it is advisable to automatically control the purge water flow according to the salt content of the saturated steam generated by the boiler.

 The specified technical result in the implementation of the invention is achieved by the fact that in the known method of operation of the drum boiler, saturated steam is obtained by evaporating the boiler water and is discharged through the steam line, continuous purging is carried out from the last stage of boiler water evaporation. The peculiarity lies in the fact that the flow rate of purge water is controlled by the salinity of saturated steam.

 The drawing shows a diagram of a drum boiler that implements the proposed method.

 The drum boiler contains the first stage of boiler water evaporation - drum 1, the second (last) stage of boiler water evaporation, made in the form of a remote cyclone 2, purge water pipe 3, feed water pipe 4, feed water flow regulating body 5 installed on pipe 4, a purge water flow regulator 6 connected to a saturated steam salinity sensor 7 and a purge water flow regulator 8 installed on the pipeline 3, steam line 9.

 The method is implemented as follows.

 Feed water is supplied through line 4 to the first stage of boiler water evaporation — drum 1. Continuous purging is carried out from the last stage of boiler water evaporation — a remote cyclone 2 through line 3. A sensor 7 installed on the steam line 9 measures the salinity of the saturated steam generated by the boiler. The signal from the sensor 7 is continuously fed to the input of the purge water flow regulator 6, the output of which is connected to the purge water flow regulator 8 installed on the pipeline 3. When a situation arises when the salinity of saturated steam exceeds the normalized value by the signal from the sensor 7 of salinity of saturated steam by the regulator 6 of the purge water flow, a command signal is generated to increase the purge water flow. The command signal generated by the regulator 6 acts on the regulatory body 8, which increase the flow rate of purge water. By increasing the flow rate of purge water, the salt content of the boiler water moving along the circulation circuits of the drum boiler is reduced, and as a result, the salt content of the saturated steam generated by the boiler is reduced to a standard value. If the opposite situation occurs, when the salt content of the saturated steam generated by the boiler is below the standard value, which indicates a lower salt content of the boiler water, the automatic control system reduces the flow rate of purge water. By reducing the flow rate of purge water, the mass loss of the boiler water and the heat contained therein are reduced.

 The level of boiler water in the first stage of evaporation, at which the normal operation of the drum boiler is ensured, is maintained by changing the flow rate of the feed water by the regulating body 5 installed on the pipeline 4.

 Thus, by automatically controlling the flow rate of purge water according to the salt content of the saturated steam generated by the boiler, the reliability and efficiency of the drum boiler operation are increased.

Claims (1)

 The method of operation of the drum boiler, in which saturated steam is obtained by evaporating the boiler water and is discharged through the steam line, continuous purging is carried out from the last stage of boiler water evaporation, characterized in that the purge water flow is controlled by the salinity of saturated steam.