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High Pressure Heater in Turbine Generator

Release time:

2025-01-02

High Pressure Heater in Turbine Generator

The high pressure heater is the main equipment in the boiler feed water reheating system of the turbine generator set. It uses the steam turbine to heat the high pressure feed water from the feed pump, so that the boiler feed water temperature reaches the required temperature, reduces the amount of steam discharged to the condenser, improves the flow characteristics of the turbine and the heat loss of the unit, reduces the coal consumption, and improves the cycle thermal efficiency of the unit. The high pressure heater is provided with a superheated steam cooling section, a condensation section and a hydrophobic cooling section. The superheated steam cooling section is used to increase the feed water temperature by the sensible heat of the superheated steam extracted by the steam turbine. It is located on the flow side of the feed water outlet and is sealed by a cladding plate. The superheated steam cooling section raises the feed water temperature leaving the heater to near or slightly above the saturation temperature at the extraction point pressure. The section is sealed with cladding plate, casing and heat shielding plate, which not only isolates the section from the main shell side part of the heater, but also helps to protect the tube plate and shell structure by reducing the temperature difference and the corresponding thermal stress

The superheated steam entering from the inlet nozzle flows uniformly through the pipe under the guidance of a set of partitions at an appropriate line speed and mass speed, and the steam retains enough superheat to ensure that the steam leaves the section in a dry state, so that when the steam enters the condensation section, it can prevent the damage of wet steam erosion and water erosion.

The condensing section uses the latent heat of steam condensation to heat the feedwater. A set of spacers distributes the steam evenly along the length direction of the heater. The steam entering the section flows to the tail of the heater under the guide of the spacer. The exhaust nozzle located at one end of the housing can remove non-condensing gas, and the exhaust pipe outlet is placed at the lowest pressure outside the bundle and the end of the housing where non-condensing gas is easy to accumulate. The accumulation of non-condensing gas reduces the effective hot surface, thus reducing efficiency and causing corrosion. The condensate and the additional drain that enters through the drain inlet seat or the step by step drain from the upper heater are accumulated in the lowest part of the housing, and these drains (condensate) lead to the drain cooling section.

The hydrophobic cooling section transfers the heat from the hydrophobic water leaving the condensing section to the feed water entering the heater, so that the hydrophobic temperature drops below the saturation temperature. The hydrophobic cooling section is located at the flow side of the feed water inlet and is sealed by the clad plate. After the temperature drops, the hydrophobic water flow weakens when it goes down to a heater with lower pressure, and tends to vaporize in the pipeline. The enclosure housing internally separates the section from the overall portion of the heater shell side, maintains an accurate constant drain level from the end plate and at the suction or inlet end, so that the section is closed, and the drain enters the section from the lower part of the heater shell, flows upward through the section, and exits the heater from the drain outlet tube holder located at the top of the section on the side of the shell.

PDF: High pressure heater operation and maintenance munual(1).pdf