This can be seen in Figure 12.5.1, which shows the temperature profile across a typical heat exchange surface. As water is an extremely effective barrier to heat transfer, its presence can reduce plant productivity and product quality.The presence of water in steam can causeВ aВ numberВ ofВ problems: The tips of the waves tend to break off, throwing droplets of condensateВ intoВ theВ steamВ flow. Steam flowing over this water can raise ripples that can build up into waves. The condensed water molecules will eventually gravitate towards the bottom of the pipe forming a film of water. There is always a certain degree of heat loss from the distribution pipe, which causes steam to condense. The water content of the steam produced by the boiler is further increased ifВ primingВ andВ carryoverВ occur. Although the dryness fraction will vary according to the type of boiler, most shell type steam boilers will produce steam with a dryness fraction of between 95 and 98%. The steam produced in a boiler designed to generate saturated steam is inherently wet. To remove these suspended water droplets, separators areВ installedВ inВ steamВ pipelines. Whilst careful drainage and trapping can remove most of the water, it will not deal with the water droplets suspended in the steam. It can reduce plant productivity and product quality, and can cause damage to most items of plant and equipment. Wet steam is steam containing a degree of water, and is one of the main concerns in any steam system.

Spirax sarco saturated steam calculator