Industrial Steam Boiler Pressure Parts Steam Super heater Re-heater Tubes heat energy
Boiler Pressure Parts Introduction
1. Boiler tubes are generally exposed to high pressure and temperature of steam internally, and high tem-perature of combustion externally .
2. Corrosive elements in both of them may cause severe damage to theinside and outside of the tubes. Many research works have indicated that the safe and corrosion freeoperation of boiler requires proper water monitoring and treatment.
3. This should also be extended to fuelconditions, operating and maintenance regime, during on and oﬀ periods. Under normal operation condi-tion of boiler, a protective oxide layer of Fe304 is being formed inside the tubes.
4. Accumulation of elements,such as sodium in areas like U-bends of the tubes and at water lines, deteriorates the oxide layer, so thatfresh surface of metal is continuously oxidized and thinning goes on till a pin hole like damage appears.
5. In this paper, failure analysis and aﬀecting parameters were studied and corrosion mechanisms wereidentiﬁed
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.
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.
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.