In steam plants, flash steam emerges due to the loss of pressure at the high pressure and temperature condensate returning energy or during the blowdown of the surface in the boiler. This resulting steam is thrown out of the condensate tanks open to the atmosphere, thus causing loss of energy, water and chemicals. This loss can reach 3-20% of the amount of steam produced. It is possible to prevent this loss with flash steam systems. The obtained flash steam can be used for degassing in dearator, preheating of feed water, condensate heating, cooling with absorption chiller, preheating the air or by re-pressurizing it to meet the need of plant steam.