Process condensates represent a real value to the industry as it usually contains several items of potential savings, including but not limited to heat energy and water. In most cases the condensate has become contaminated with unwanted particles or with product carryover making it unfit for direct reuse in the process or as boiler makeup water. Conventional methods use heat exchangers for partial recovery of the heat content to be followed by ion exchange or reverse osmosis limited to 30–40°C feed temperature. By using the Duratherm® High Temperature compatible membranes in RO and NF, it is now possible to process the condensate at temperatures up to 80°C thereby maintaining the calorific value of the stream. Many plants also produce a product using evaporation. The overheads from the evaporators usually contain a small amount of their product that must either be recovered by an additional evaporation step or disposed of in a waste treatment plant. These reverse osmosis or nanofiltration systems allow concentration of the product, produce high quality water suitable for reuse, and reduce the load on the waste treatment plant. The treated condensate can then be used for various utility operations including boiler & process makeup.
Keywords: condensate recovery, high temperature, nanofiltration, reverse osmosis, water reuse