Wet steam

The cobalt deposition rate on new, replacement, or decontaminated recirculation piping surface has been reduced by pretreating the piping using an atmosphere of oxygenated wet steam to form an oxide film (25). Studies have been conducted for both PWRs and BWRs to reduce the cobalt content of materials used in the nuclear parts of the plants, particularly in hardened and wear surfaces where cobalt-base alloys ( 50% Co) are used (26). Some low cobalt materials have been developed however, the use of the materials is limited to replacement parts or new plants. 

Environment Internal Untreated river water External Wet steam, pH 9.0-9.6... 

Figure 11.16 Scanning electron micrograph showing cones of brass created by impingement of high-velocity wet steam. (Magnification 50x.)...

Gas-liquid Released gas (air) bubbles rising in a large tank Mist formation from LPG evaporation Splash filling Cleaning with wet steam Mist formation from high pressure water jets... 

Dryness fraction of wet steam The mass of pure saturated steam contained in unit mass of wet steam. 

Wet steam reservoirs are much more common than the simple dry type. Again, the field is full of very hot water, under such high pressure that it cannot boil. Wdien a lower-pressure escape route is provided by drilling, some of the water suddenly evaporates (flashes) to steam, and it is a steam-water mixture that reaches the surface. The steam can be used to drive a turbine. The hot water also can be used to drive a second turbine in a binai y cycle, described in the section Electricity Generation in this article. 

Wet steam erodes the ejector nozzle and interferes with performance by clogging the nozzle with water droplets [16]. The effect on performance is significant and is usually reflected in fluctuating vacuum. 

Effect of Wet Steam. Steam turbines should not be operated with wet steam. The manufacturers will not guarantee performance when the moisture is greater than 3%. 

Basically there are two approaches to predicting the occurrence of erosion corrosion. Practical or experience based methods typified by Keller s approach for carbon steels in wet steam. Keller developed an equation that related the erosion corrosion rate as a function of temperature, steam quality, velocity and geometric factor. In recent years this approach has... 

Proc of Specialists Meeting held at Les Renardiers May 1982 on Erosion Corrosion of Steels in High Temperature Water and Wet Steam, Eds P. Berge and E. Khan, Electricite de France Paris (1983)... 

Air/water vapor mixture, chart, 364,365 Air/water vapor, 359 Capacity at ejector suction, 369 Capacity for process vapor, 362 Evacuation time, 371, 380 Load for steam surface condenser, 367 Non-condensables, 362, 363 Size selection, 371 Steam pressure factor, 373 Steam requirements, 372 Steain/air mixture temperature, 361 Total weight saturated mixture, 362 Capacity, 358 Discharge, pressure, 358 Effect of excess steam pressure, 358 Effects of back pressure, 359 Effects of wet steam, 356 Inter-and-after condenser, 351 Load variation, 370 Materials of construction, 347 Molecular weight entrainment, chart, 360 Performance, 358, 370, 375 Relative comparison, 357... 

Steam containing water droplets is termed wet steam and has a reduced enthalpy. 

The wet steam passes through steam-water separators within the top drum. Separated water is returned to the inlet of the external downcomer, while the moist-to-dry steam may pass through a secondary steam-water separator to remove any residual moisture before passing into the steam header part of the steam delivery system. 

Enhanced Oil Recovery Boilers Enhanced oil recovery boilers provide HP wet steam for enhanced oil recovery. The steam is injected into oil-bearing strata, to heat the oil and reduce its viscosity, thereby increasing the potential for flow. 

The generation of clean, uncontaminaled steam is a fundamental objective for all facilities. Most users also require the steam to be as diy as possible, although certain applications can tolerate or even require wet steam. 

The production of dry steam is important because wet steam may damage equipment and machinery, breaking valves and fittings and causing deposits in superheaters and turbines. 

Where condensate forms from the wet steam and drips back through the system, water hammer may develop and cause severe damage. 

Wet steam, which leads to interrelated steam quality issues, as discussed earlier... 

Poor steam quality Inadequate steam/water separation results in wet steam with reduced heat content. 

A2. Adorni, N., Bertoletti, S., Lesage, J., Lombardi, C., Peterlongo, G., Soldaini, G., Weckermann, F. J., and Zavattarelli, R., Results of wet steam cooling experiments pressure drop, heat transfer and burnout measurements in annular tubes with internal and bilateral heating, CISE-R.31 (1961). 

Table 23.2. Chemical compositions of water and steam discharged from wet-steam geothermal wells in Iceland (Arnorsson et al., 1983)...

Fig. 23.8. Calculated saturation indices (log Q/K) of various minerals for the Reyk-janes 8 wet-steam geothermal well. The well produces from seven intervals at temperatures varying from 274 °C to 292 °C. The calculated saturation indices suggest an equilibrium temperature between about 285 °C and slightly above 300 °C.

Fournier, R. O. and J. J. Rowe, 1966, Estimation of underground temperatures from the silica content of water from hot springs and wet-steam wells. American Journal of Science 264, 685-697. 

As the pressure in the engine cylinder is always much lower than the saturation pressure of the water in the coil, once it is injected there is no possibility for the water to remain in the liquid phase and part of it flashes into steam. The flashing process results in wet steam because only part of the water is converted to steam while the rest is atomised by the flashing process into tiny droplets of water. 

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