High Efficient Reheater In Thermal Power Plant Heat Exchanger ASME Standard

Product Description

Superheaters are the one of the most important parts of boiler that improve the heat exchange efficiency.

In boiler, the role of superheater is to heat saturated steam to a certain temperature of superheated steam to improve power plant efficiency.In essence, the repeater improves the recycling efficiency of thermal power plant.

Superheater is the temperature of the steam above its saturation point.

A reheater is basically a superheater that causes the steam to overheat from the high-pressure stage of the turbine.The reheated steam is sent to the low pressure stage of the turbine.By reheating the steam between the high-pressure and low-pressure turbines, the electrical efficiency of the power plant cycle can be increased to more than 40 percent.Reheat recycling is used on large boilers because it is economically viable only in large power plants.

Details

Superheater

Generally 30 ~ 60 mm.The most common type of flow superheater is serpentine tube.It has a more intensive tube group, decorate in 450 ~ 1000 ℃ flue of the flue gas temperature, flue gas of vertical and lateral erosion.The flue gas mainly transfers the heat to the pipe by convection, and some of the heat is absorbed by radiation.The plate-type superheater consists of a plurality of tube screens, arranged in the upper part of the furnace or at the outlet, belonging to the radiation or semi-radiation type superheater.The former absorbs radiant heat from the furnace flame, while the latter also absorbs some convection heat.In power station boilers above 10 mpa, both screen type and serpentine type superheater are commonly used to increase heat absorption.The wall superheater applied on the inner wall of the furnace is radiant superheater, which is seldom used.The wall-mounted superheater is used in the large capacity power station boiler to form the wall of the furnace top and convection flue.The picture shows the arrangement of several superheater.The small capacity industrial boilers with superheater can meet the requirements only with single stage superheater.

Reheater

The reheater layout follows the superheater layout, including convection, radiation and semi-radiation.

The convection reheater has reverse flow, downstream flow and mixed flow, single coil, double coil, multi-coil, parallel and staggered, vertical and horizontal type, parallel to the front wall and perpendicular to the front wall.Convection reheater is the main reheater that absorbs convection heat.

Radiant reheater refers to the reheater absorbing furnace radiation.

Semi-radiant reheaters (plate superheater) refer to reheaters that absorb more radiation from the furnace (more than 1/2 of the total heat).

The material selection principle of reheater is the same as that of superheater. Since reheating steam is inferior to superheater in cooling capacity, the design wall temperature is generally higher than that of superheater of the same temperature level.Metal tubes of high temperature reheaters are generally made of alloy steel (metal tubes containing more than 5% of alloy elements).For example, 12CrlMoV, steel 102, sa213-t91, sa213-tp304, sa213-tp347, etc.

Differences

Application

Use for heating saturated steam, steam temperature could be up to 900 degree C.
Superheater Capacity Upgrades to Increase Power Generation

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