Quality, of steam

There are various factors that affect the quality of steam/ water separation, such as ... 

The provision of free caustic alkalinity in higher pressure boilers (say, 300-950 psig) generally is severely limited or even curtailed to ensure a high quality of steam purity and to control the risks of foaming and other problems developing. 

The quality of steam can be measured by a permanently installed throttling calorimeter. 

The quality of steam produced in electrode boilers is greatly affected by the quality of the electrolyte. For jet steam boilers, the BW should be demineralized water, with conductivity provided by adding an electrolyte. For other types of electrode boilers, the FW supplied should be fully softened, as a minimum. 

The approximate equations should not be used for steam, as the quality of steam depends on its pressure, and hence the pressure drop. 

A steam Carnot cycle operates between 250°C and 100°C. Determine the pump work, turbine work, heat added, quality of steam at the exit of the turbine, quality of steam at the inlet of the pump, and cycle efficiency. 

An ideal Rankine cycle uses water as a working fluid, which circulates at a rate of 80kg/sec. The boiler pressure is 6 MPa, and the condenser pressure is 10 kPa. Determine (1) the power required to operate the pump, (2) the heat transfer added to the water in the boiler, (3) the power developed by the turbine, (4) the heat transfer removed from the condenser, (5) the quality of steam at the exit of the turbine, and (6) the thermal efficiency of the cycle. 

A steam reheat Rankine cycle operates between the pressure limits of 5 and 1600 psia. Steam is superheated to 600° F before it is expanded to the reheat pressure of 500 psia. Steam is reheated to 600°F. The steam flow rate is 8001bm/hr. Determine the quality of steam at the exit of the turbine, the cycle efficiency, and the power produced by the cycle. 

A mixture of vapor and liquid is in equilibrium. The density of the mixture is 0.99 lb/ft3. From the Steam Tables, determine the quality of steam for the conditions of 305°F and 72.2 psia. 

In some instances, the quality of steam may be given instead of its moisture content in percent. The quality of steam is the percent vapor in the mixture. In the preceding calculation, the quality of the steam is 60% because 40% is moisture. Thus, quality = 1 — m, where m is percent moisture, expressed as a decimal. 

These experiments demonstrated that the passivating qualities of steam pretreatment may be partially associated with the generation of a silica-rich oxide. However, brief attempts to increase the surface concentration to approach a continuous silica layer excluding all the alloying metals (by variations in preoxidation conditions) met with failure, exhibiting bulk inhomogeneity and oxide spallation problems. Further, many ESC plants are constructed with radiant coil alloys low in silicon content, and so preoxidation can only be considered a partial palliative. Hence, attention turned to the prospect of coating the internal surfaces of radiant coils with a thin, continuous layer of silica. 

Decrease quality of steam, ending up by admitting 212°F.-water at atmospheric pressure. Flush water through each line by proper valving to assure complete removal of sodium. 

U.S. Bureau of Mines — Mineral Industry Survey — Fuel Qil Sales Annual, Federal Power Commission — Annual Summary of Cost and Quality of Steam — Electric Plant Fuels... 

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