Active Member
|
[China]
Address: No.1, Huangqi Road, Li village
Contact name:Edwin
Zhangjiagang Dehai Boiler Co., Ltd |
|
|
Energy Saving Steam Boiler Heating Part Superheater And Reheater CFB Boiler spare parts
Boiler Reheater Brief Introduction
1. In large capacity boilers, the superheater and reheater temperature at the boiler outlet is controlled by many methods. Water spraying in both superheater and reheater is a very commonly adopted method.
2. In using a spray water system, there are many points to be addressed as otherwise serious failures can result. The superheaters and reheater are sized in such a way that the full steam temperatures are achieved from 60 % boiler load.
3. This means the steam temperature will be much higher than the rated steam temperature. Hence, to control this increase, water spraying is adopted.
4. These desuperheaters are designed in such a way that the water is split into fine particles and allowed to mix with the steam, ensuring no water particles remain as it enters the superheater.
Processing
1. The superheated steam then flows through the main steam piping to the high-pressure turbine. Exhaust steam from the high-pressure turbine is guided to the boiler for reheating and from there to the intermediate and low-pressure turbines.
2. High reheating temperatures improve the output and efficiency of a power plant.
Reheater Function
1. Therefore the number of reheat stages can not be many as the pressure drop will reduce efficiency of thermal cycle.The steam pipes and reheater coils are to be so designed to limit the drop to 2–3%.
2. The control valves in reheat steam path is not desirable.Systems using HP LP bypass require these valves to control steam flow during bypass operation.
3. The efficiency of the Reheat cycle can be improved by increasing the pressure and temperature of steam entering into the turbine. As the initial pressure increases the expansion ratio of the turbine also increases and the steam becomes quite wet at the end of expansion.
Main Advantage
The main advantage of reheat cycle is to reduce the specific consumption and consequently reduce the size of the boiler and other auxilaries for the same power.The reheat cycle is preffered for the high capacity above 100 MW plant.
Differences
| Type | Advantages | Disadvantages | Supporting method |
| Pendant-type | 1.Firm structural support | 1. Flow blockage by condensed steam 2. Needs slow restart to purge the water that accumulates in the bottom. | supported from above |
| Inverted-type | 1.Proper drainage of the condensed steam | 1. Lack the structural rigidity, especially in high speed gas flow | Supported from below |
| Horizontal -type | 1. Proper drainage 2. Good structural rigidity. | 1. They do not view the flam directly so they are mainly from the convective type | Usually supported in the vertical gas ducts parallel to the main furnace. |
After beveling
