ASME Standard Heat Insulation Superheater and Reheater Coils Anti Corrosion
Function
A reheater is basically a superheater that superheats steam exiting the high-pressure stage of a turbine. The reheated steam is then sent to the low-pressure stage of the turbine. By reheating steam between high-pressure and low-pressure turbine it is possible to increase the electrical efficiency of the power plant cycle beyond 40%.The reheat cycle is used in large power boilers since it is feasible economically only in larger power plants.
Superheater
| In a subcritical boiler, the SH is between the main-steam header and the steam drum and consists of |
| • Saturated tubes that transport steam from the drum to the SH inlet header (when the SH tubes are not directly connected to the drum) |
| • Superheater banks with their respective inlet and outlet headers |
| • Attemperator station for STC |
| • Main-steam header with all fittings and terminating with the main-steam stop valve (MSSV) |
| Steam from the steam drum flows toward the main-steam header, and there should be no valve between the two to ensure flow in SH tubes under all conditions to prevent overheating and failure. |
Reheater
Reheating of steam involves withdrawal of partly expanded steam (at the end of the high — pressure cylinder of the turbine), taking it back to the boiler in cold reheat pipes, heating to the same or higher temperature as the superheated steam, and returning to the turbine in hot reheat pipes. In terms of hardware, an RH system comprises
| • Cold reheat pipe from turbine to boiler |
| • Safety valves on the cold reheat pipe |
| • Emergency spray-water attemperator system on a cold reheat pipe or interconnecting pipe |
| • Reheater bank complete with inlet and outlet headers |
| • Hot reheat pipe from boiler to turbine |
Testing
Manufacturing and acceptance criteria
JB/T1611 " Technical specification for manufacturing of boiler pipes."
JB/T1612 "boiler pressure test technical conditions. "
JB/T1613 "Technical specification for welding of pressure parts of boiler."
JB/T1615"Technical specification for painting and packing of boiler."
JB/T3375 "Rules for receiving acceptance of materials for boiler construction."
Company Introduction
Established in 1985,Zhangjiagang Hua Dong Boiler Co.,Ltd.(trading as HD Boiler),produces power plant; industrial; waste heat; waste incineration; biomass; organic heat carrier and electric steam boilers. Coupled with a comprehensive range of heating surfaces, HD Boiler brings to the market a unique service including boiler design , fabrication, installation, maintenance and replacement of boiler pressure parts.
1. Fabrication area of 200,000 square meters
2. 150 Engineers
3. 600 Coded welders
4. 60 Licensed Inspectors(NDT Level-III instructors)
5. Class-A Licenses for Design and Manufacture Boiler
6. ISO 9001:2008 Quality System
7. ASME Certificate of Power Boilers
8. ASME 'S','U' and NB stamp authorization
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ASME Standard Heat Insulation Superheater Reheater Coils Anti Corrosion Images
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