RU2115862C1 - System of delivery of feed water to spray-type attemperator (of boiler) - Google Patents

Abstract

FIELD: control of superheat temperature of steam generated by boiler units (steam generators) of thermal power stations. SUBSTANCE: system of delivery of feed water to spray-type attemperators of boiler includes spare lines fitted with adjusting valves and brought in communication with feed main through branch pipe provided with throttling device. Inlet sections of spray lines are connected to dispensing header; outlet section of branch pipe after throttling device is connected only to above-mentioned header. Throttling device is made in form of adjusting throttle valve whose regulator is connected with water pressure pickup fitted in header. Pressure setting of valve regulator is so selected that pressure at throttle valve and adjusting valves of spray lines is maintained at level ensuring their erosion safety. EFFECT: enhanced erosion safety. 1 dwg

Description

 The invention relates to energy and can be used in devices for controlling the temperature of the superheat of steam produced by boiler units (steam generators) of thermal power plants.

 The steam temperature at the outlet of the boiler superheater and along the steam path is one of the most important parameters that determine the efficiency and reliability of the boiler and the power unit as a whole. The most common way to control the temperature of steam using injection desuperheaters, in which boiler feed water is used as a cooling agent under the condition of high-quality chemical water treatment.

 A known system for supplying feed water to the boiler desuperheaters, comprising injection lines connected to the feed line via a branch with a throttle device with control valves on each injection line. In this system, related to once-through boilers, it is provided that standard injections are powered behind the integrated valve, as well as starting injections (having different steam pressures in starting and reduced load modes), from one source of high-pressure feed water. At the same time, to reduce the pressure of water taken from the feed line to a level that ensures normal operation of the injections (under the conditions of preventing erosive wear of control valves on the injection lines), in the start-up and reduced load modes a throttle device is provided in the form of a package of throttle washers with a parallel discharge of part of the taken from the feed water pipeline to the deaerator. This solution, allowing to reduce the pressure of the water supplied to the injections to acceptable under the conditions of erosive wear of control valves on the injection lines, leads at the same time to significant losses of feed water for recirculation to the deaerator and does not prevent erosive wear of the throttle device forced at low vapor pressure a significant pressure drop is triggered.

 The achieved result of the invention is the prevention of erosive wear of control valves on the injection lines and the throttle device while increasing the efficiency of the feed water supply system for standard boiler injection desuperheaters by eliminating its discharge into the deaerator.

 To ensure the specified result according to the invention, in the feed water supply system to the boiler desuperheaters containing the spray lines connected to the feed line through the branch with a throttle device with control valves on each injection line, according to the invention, the input sections of the injection lines are connected to the distribution manifold, the outlet section of the outlet after the throttle device is connected only to the specified collector, and the throttle device is made in the form of a regulating throttle valve, the regulator of which is connected to a water pressure sensor installed in the manifold, and the setpoint for the pressure of the valve regulator is selected from the condition of maintaining differential pressure on the throttle valve and control valves on the injection lines, ensuring their erosion safety.

 The drawing schematically shows a system for supplying feed water to injection desuperheaters in relation to a drum boiler, made in accordance with the invention.

 An outlet 3 with a throttle device in the form of a regulating throttle valve 4 and a distributing manifold 5, to which injection water supply lines 6 with individual control valves 7 are connected, is connected to the boiler feed line 1 (not shown in the drawing) in front of the control valve 2 for supplying water to the steam generator on each injection line. Branch 3 from the supply line from its output side is connected only to the collector 5, without having a branch to the deaerator. The regulator 8 of the throttle valve 4 is single-pulse and connected to the water pressure sensor 9 installed in the manifold 5, and the pressure setting of the regulator 8 of the valve 4 is selected from the condition that the differential pressure is maintained on the throttle valve 4 and control valves 7 at predetermined intervals ensuring their erosion safety ( the maximum permissible values of pressure drops across the valves are usually given in the factory product data sheet).

 The system operates as follows.

 Using valves 7 on the lines 6 of the injection is regulated within the specified limits of the temperature of the superheated steam. To eliminate the mutual influence of individual valves 7 connected to a common distributing manifold 5, in the latter, a constant pressure is maintained by the signal from the sensor 9 by regulating the regulator 8 of the throttle valve 4, the value of which is determined by the set point of the regulator 8. This set point, in turn, is set based on the optimal the distribution of pressure drops on the control valves 7 and the throttle valve 4, which ensures the absence of erosive effects on the valves of the flow passing through them in dy. To control the system, it is possible to use remote control with moving the working body of the throttle valve 4 according to the pressure gauge connected to the distributing manifold 5.

 The proposed system allows to increase the reliability of its operation by preventing erosive wear of control valves on the injection lines and the throttle device by maintaining erosion-safe pressure drops on them, as well as increasing efficiency by eliminating the discharge of part of the feed water taken into the injection into the deaerator.

Claims (1)

 The feed water supply system to the boiler desuperheaters containing the injection lines communicated with the feed line through the branch with the throttle device with control valves on each injection line, characterized in that the input sections of the injection lines and the outlet section after the throttle device are connected to an additionally installed distribution manifold and the throttle device is made in the form of a regulating throttle valve, the regulator of which is connected to the sensor installed in the collector water pressure, and the setpoint for the pressure of the valve regulator is selected from the condition of maintaining differential pressure on the throttle valve and control valves on the injection lines, ensuring their erosion safety.