Internal structure and function of low pressure heater

In the thermal system, the low-pressure heater plays a key role, it is through the exquisite internal structure to achieve efficient heat exchange. The following is a detailed introduction to its internal structure and its role.

1. Heat transfer tube: as the core component of heat transfer, it is the key to realize heat exchange of low pressure heater. The main condensate water is heated in the pipe, and the steam extracted from the steam turbine is extracted outside the pipe. The heat transfer is carried out through the pipe wall, and the heat of the steam is transferred to the main condensate water, thereby increasing the feed water temperature. Brass pipe corrosion resistance, suitable for corrosive media conditions; Seamless steel pipe has high strength and can withstand high pressure. The structure of the U-shaped tube bundle can effectively compensate for thermal expansion, avoid excessive thermal stress and damage at the connection of the pipe and tube plate due to temperature changes, and ensure the safe and stable operation of the equipment.

2. Diaphragm: 

Support tube bundle: When the low-pressure heater is running, many heat transfer tubes are densely arranged, and the partition provides support points for the tube bundle to prevent the tube bundle from bending, deformation or vibration under the impact force generated by the steam flow and its own gravity, so as to ensure the structural integrity and stability of the tube bundle.

Optimization of steam flow: A reasonably arranged partition can guide the steam to flow according to a specific path, so that the steam evenly transverse scour the heat transfer tube, increase the contact area and time between the steam and the heat transfer tube, strengthen the heat transfer effect, and improve the heat exchange efficiency of the heater.

3. Anti-impact plate: when steam or hydrophobic high-speed into the heater shell side, will cause a large impact on the tube bundle, long-term impact is easy to make the tube bundle surface wear, thinning, and even damage. The anti-impact plate can buffer the impact force of steam and drainage, change its flow direction, make the medium evenly dispersed, avoid local centralized impact on the tube bundle, extend the service life of the tube bundle, and ensure the normal operation of the heater.

4. Cladding plate:

Division of functional areas: the superheated steam cooling section and hydrophobic cooling section are separated from other areas on the shell side, so that the steam and hydrophobic flow in their independent Spaces according to the design process, to ensure that the working process of different functional sections does not interfere with each other, and to achieve the corresponding heat exchange function.

Maintain a specific water level: After the internal part is separated from the overall part of the heater shell side, the required drainage level of each section can be maintained to a certain extent, to ensure that the drainage cooling section can effectively cool the drainage, and the superheated steam cooling section can make full use of the steam sensible heat to heat the water supply.

5. Water Room:

Distribution and collection of water flow: After the main condensate water enters the water chamber, it is evenly distributed to each heat transfer tube to ensure that the water flow of each heat transfer tube is uniform, so that the heat exchange is more balanced. After heating, the water is collected in the water chamber and then flows out of the heater to complete the heating process.

6. Connecting pipe: The water chamber is connected with the external main condensate pipe through the inlet and outlet pipes, which plays a role of connection and transition, so that the main condensate can flow into and out of the heater smoothly.

7. Steam cooling section: The sensible heat of superheated steam extracted from the turbine is used to further heat the feed water. On the one hand, the feed water temperature is increased, and the cycle efficiency of the whole thermodynamic system is enhanced. On the other hand, when the steam leaves the section, it can reach a dry state, avoid the wet steam entering the subsequent condensation section, reduce the erosion and corrosion of the equipment, extend the service life of the equipment, and improve the safety and reliability of the system operation.

8. Condensation section: Condenses the saturated steam into saturated condensate on the outer surface of the tube bundle. In this process, the steam releases the latent heat of vaporization and transfers it to the main condensate in the pipe, which is the main area for the heater to achieve heat exchange and plays a key role in raising the temperature of the main condensate. At the same time, the arrangement of the partition helps to evenly distribute the steam, strengthen the heat transfer process, and improve the heat exchange effect.

9. Hydrophobic cooling section: The hydrophobic water leaving the condensation section is further cooled so that its temperature is reduced below the saturation temperature. This can reduce the possibility of hydrophobic vaporization due to reduced pressure in subsequent pipelines, avoid cavitation, and protect pipelines and related equipment. In addition, the heat released by cooling the drain is used to heat the low-temperature feed water entering the heater, improving the thermal efficiency of the entire heater and reducing energy loss.