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Best Practice Guide |
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Food and Beverage Growers and Processors |
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SteamWaste Heat RecoveryCondensate Recovery
Recovered condensate is, quite simply, distilled water. It is ideal for boiler feedwater since it requires minimal chemical treatment and filtration, saving on water, wastewater, energy, and chemical costs. As described in the chapter on boilers, it takes a great deal of energy to treat and heat feedwater to generate steam. In most cases, reusing condensate is more cost-effective than using new utility water. Less obvious than water savings, energy savings are realized because it takes substantially less fuel to convert recovered condensate into steam. Utility water typically enters the boiler-steam system at temperatures between 50ºF and 80ºF, and is then heated to more than 212ºF (the boiling point of water). The temperature of recovered condensate, on the other hand, can exceed 200ºF. A condensate recovery system relies on little additional equipment: receiver tanks to store recovered condensate and help normalize pressure, insulated pipes to return condensate to the boiler, and pumps to move condensate through the pipes. Flash Steam Recovery Recovered condensate tends to be high pressure and high temperature. As this condensate enters the return system, pressure is reduced. Steam is generated at different temperatures as pressure changes. Thus, as pressure is reduced, liquid condensate at high temperatures causes "flash" steam. A flash steam recovery vessel installed downstream from the steam trap will collect flash steam and redirect it to an end-use application while directing saturated condensate to return piping. Resources U.S. Department of Energy, Best Practices Steam program: 3E Plus - a software program to optimize the installed thickness of mechanical insulation. Helps the user determine fuel savings and emissions reductions under varying operating conditions. Ensuring Energy Efficiency Through Effective Monitoring of Steam. Solartron Mobrey Ltd. Reproduced by Energy Solutions Center, Inc., Boiler Burner Consortium. Yoder, Jesse L., Ph.D. Using Meters to Measure Steam Flow. Plant Engineering Magazine, April 1998. Reproduced by Flow Research, Inc. |