ASME Standard Superheater And Reheater Heat Exchange Boiler Parts High Efficiency

ASME Standard Superheater And Reheater Heat Exchange Boiler Parts High Efficiency

Product Introduction

Reheater is essentially a kind of steam superheater which reheats the low-pressure steam which has been overdone and reaches a certain temperature. The reheater further improves the heat efficiency of power plant circulation and controls the steam temperature of the final stage blade of steam turbine within the allowable range.A reheater is a heater that converts steam from a steam turbine into superheated steam.There are two functions of reheater. One is to reduce the humidity of water vapor, which is helpful to protect turbine blade.Second, the relative internal efficiency and absolute internal efficiency can be improved.

Type Advantages Disadvantages Supporting method:

Pendant-type

Details

Design structure

1. heating saturated steam, temperature up to 900 degree C.

2. high efficiency, >90%.

3. high speed heating.

4. design with stainless steel.

5. long design service life, 15 years.

Product function

In order to improve the heat efficiency of large generating sets, intermediate reheat cycle is widely used.The main steam coming out of the boiler superheater is sent to the reheater to increase the temperature after the work is done in the high pressure cylinder of the steam turbine. Then it is sent to the middle pressure cylinder of the steam turbine to continue expansion and work.Some large units, after the middle pressure cylinder will exhaust steam back to the boiler heating, known as two intermediate reheat cycle, can be relatively improved circulation efficiency of about 2%.Some test units even adopt three reheat cycles.After the reheat cycle is adopted, the thermal system, structure and operation adjustment of the boiler and steam turbine device become complex and the cost increases, so it is adopted in the generating units of more than 100 megawatts, usually only once intermediate reheat is used.

Product Features

The steam flow resistance in the reheat system has a greater impact on the unit's cycle thermal efficiency, which decreases by 0.2 ~ 0.3% for every 0.1 mpa increase in resistance.Therefore, larger pipe diameters (42 ~ 60 mm) and lower steam mass flow rate (250 ~ 400 kg/(meter 2· s.) are commonly used to control reheater body resistance not to exceed 5-7% of its inlet steam pressure.The pressure of the reheated steam is lower than that of the main steam, and the convection heat transfer of the steam inside the pipe is poor to the pipe wall. Therefore, the metal temperature of the pipe wall is higher, and better high-temperature steel should be adopted, and even chromium nickel austenitic steel should be adopted.The temperature of reheating steam can be adjusted (see steam temperature regulation of boiler).

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