Industrial Steam Quality Or Steam Purity.
Today we will talk about industrial steam quality or steam purity. This is because steam is widely used in various industries including various types of equipment such as turbines, pump drivers, power generation, steam reforming, heating, dehydration, etc. Now if the industrial steam quality or steam purity is not right. However, important types of machinery are likely to be damaged. In that case, we must maintain industrial steam quality or steam purity.
# Poor quality steam refers to high moisture content, steam is best when superheated. From the perspective of Process Design Engineering, we assume that even saturated “steam” is dry.
* In reality, steam in most process plant piping systems is wet. Often steam is wet because of ambient heat loss.
* Dry steam is actually invisible. Steam venting from a line only looks white because the steam is wet.
* Wet steam is generated from boilers because of the entrainment of Boiler Feed Water(BFW) into the evolved steam.
* Entrained boiler feed water contains salts. The Total Dissolved Solids (TDS) of the entrained water is the same as the boiler blowdown
* Salt content of the blowdown water is 10-20 times > the salt content of the boiler feedwater. That’s why moisture in steam due to entrainment is more serious than moisture in steam due to condensation. Condensed moisture is free of salts.
️* For Steam Turbines Moisture in the supply steam contains salts. The salts slowly accumulate on the turbine blades and reduce horsepower output. When these deposits break off, the turbine rotor is unbalanced. The resulting vibration will cause the shutdown of the turbine.
*️ For Steam Superheat Furnace Tubes salts in entrained moisture from a boiler will deposit inside the superheat coils. Localized overheating and tube rupture will result.