Water carryover

Other items unique to steam turbines that must be considered are water carryover and fouling. Carryover can leave deposits on the blading, causing loss in performance and increased thrust loads. If carried to an extreme, thrust bearing failure could occur. If a large amount of water is carried over as a slug of liquid, catastrophic failure can occur. 

Provide a suitable method to prevent water carryover in the cleaned exhaust gas. 

Few plant operators need to be told of the problems caused by water in compressed air. They are most apparent to those who operate pneumatic tools, rock drills, automatic pneumatic powered machinery, paint and other sprays, sandblasting equipment, and pneumatic controls. However, almost all applications, particularly of 100-psig power, could benefit from the elimination of water carryover. The principal problems might be summarized as ... 

Efficiency is related to turbine loading and the response to changes in operation. Key factors in part-load turbine performance are the operational methods employed to control steam flow to the turbine and the actions taken to reduce boiler cycling, low-load conditions, and boiler water carryover. 

A lack of quiet time in the knockout can also cause excessive water carryover with the oil. 

Well, we have already discussed this phenomenon in Chap. 1, in the section on tray flooding. Water carryover from the top of tray 1, as shown in Fig. 15.1, is simply a clear signal that our little four-tray distillation tower is flooding. But what is causing the trays to flood ... 

This requirement provides a significant cost in fuel gas to heat the water. At a 20,000-mVday refinery with a desalter outlet temperature of 100 C and a crude-oil heater outlet temperature of 315 C, each tenth of a percent of water carryover will result in 20,000 kg of water being heated 215 C to form... 

PP containing 0.1 phr additive was extruded at 260°C into a 5 mil film that was quenched in a 37.8°C water bath. Tachometer measurements of the film speed at the point of water carryover was recorded. The higher the number, the faster the production would be, which is preferred. 

GS-680 Drain Water carryover Modify post-V-680 trap... 

Moreover, for PP tape manufacturing with water bath quenching, the water-carryover effect can also be affected by choice of stabilizer (where the additive... 

For example, a high MW hindered amine (eg, CYASORB UV-3346 Light Stabilizer) combined with CYASORB UV-2908 provides synergistic performance in PP slit tape applications during Xenon ARC WOM exposure (Fig. 11) (64). The use of this combination also allows improved processability in production of the slit tapes because of reduction in water carryover compared with HALS alone. It has also been demonstrated that, in thick section PP, long-term stability can be dramatically improved with CYASORB UV-3346 combined with CYASORB UV-2908. 

Reducing the likelihood of overfilling the steam generators, possibly causing water carryover to the turbine. 

Extraction resistant phenolic AO with low water carryover for film and tape Irganox 1425 ML ... 

Both dry-feed designs currently experience startup of demonstration-scale gasifiers in the range of 1000 t/d single-unit capacity [99,101]. Both systems use a dip tube for gas cooling with special bubble distributor devices reducing water carryover [103], The gas exits the gasifier aroimd saturation temperature (220-250 °C) and the final particulate removal is achieved with a jet mixer, a cyclone, and a water scrubber [2]. 

The carryover can occur as a result of mechanical or chemical causes. Carryover is generally classified as foaming, priming, or general entrainment in the steam. Some of the mechanical factors that influence boiler water carryover are ... 

At 25°C, the pH at which carbonic acid is completely converted to morpholine bicarbonate is slightly higher than 7.3, bnt it shonld be noted that contamination of the condensate by 1% of a synthetic boiler water raised the pH from 7.3 to 8.0 and lowered the untreated corrosion rate. Due to this phenomenon, plants having trouble with boiler-water carryover in the steam usually do not have condensate corrosion problems as serious as those where there is no carryover. Morpholine is stable at high temperatures and pressures and is evenly distributed. For effective corrosion control, a pH of 8.8 to 9.0 and a morpholine residual of 3 to 4ppm are maintained. Morpholine is stable up to a boiler pressure of 170 bar (2500 psi) and to 650 °C (1200 °F) in superheated steam. 

The oily bubbles rise to the siurface as an oily foam, which is then skimmed from the surface of the bulk water phase. This skimming process acts to collapse the foam, which further concentrates the oily phase. Skimming is usually achieved by a combination of weirs and skim paddles that move the oily foam to the edge of the cell and over the weir. The weir height relative to the position and speed of the skim paddles must be adjusted to prevent both excessive foam build-up on the bulk water surface and excessive water carryover into the oil skim bucket located below the weir. 

After all, the external level indication chamber (level-trol) holds just water. When we look at the gauge glass, it has water, not steam. Hence, the indicated water level outside the drum is less than the boiling water level inside the drum. This discrepancy causes water carryover with the steam due to high boiling water levels. 

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