Industrial Boiler Reheater and superheater with water spray system Chinese qualified manufacturer
Boiler Reheater Introduction
1. What is Reheater on Boiler? – Reheater is a part of boiler which to reheat steam output from the first level of steam turbine. 2. Reheated steam will again absorb the heat energy from boiler to be used in the next level steam turbine.
3. Reheater is one way to improve the thermal efficiency of the Rankine Cycle.
4. The Rankine Cycle equipped with a reheater, will have at least two levels of steam turbine: high pressure turbine and low pressure turbine.
5. High pressure steam turbine output steam, commonly known as cold reheat steam, has lower pressure and temperature of main steam, before entering the turbine. Although the cold reheat pressure is drop significantly, it still has not reached its saturation point.
6. So, if this steam reheated, it will return to superheated steam. Therefore the cold reheat steam that exits the high pressure turbine, will be reheated back into the boiler.
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.
Spray in Superheaters and Reheaters of High Capacity Boilers
1. In large capacity boilers, the superheater and reheater temperature at the boiler outlet is controlled by many methods.
2. Water spraying in both superheater and reheater is a very commonly adopted method. In using a spray water system, there are many points to be addressed as otherwise serious failures can result.
3. The superheaters and reheater are sized in such a way that the full steam temperatures are achieved from 60 % boiler load. This means the steam temperature will be much higher than the rated steam temperature.
4. Hence, to control this increase, water spraying is adopted. 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.
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
1.Proper drainage of the condensed steam
1. Lack the structural rigidity, especially in high speed gas flow
Supported from below
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.