New Method and Systems of Blowdown Heat Recovery

Water fed to the steam generator SG contains suspended and dissolved solids. When the water evaporates, most of these solids remain in the drum. For maximum performance, the concentration of dissolved solids in the SG water should be maintained within the limits recommended by the boiler's manufacturer. For this reason, part of the SG water is drained from the system. Some solids are light and float on the surface of the drum's water. The surface blowdown is usually made on a continuous basis. When the steam consumption is increased more make-up flow is supplied to the steam generator, and more blowdown flow is required. The common practice is to use the energy wasted with blowdown to heat the make-up water. It is also necessary to cool the blowdown water to 140 deg. F in accordance with the requirements of the environmental agencies to eliminate the drain of hot water to the sewage system.