Feed-condition line quality

Since the boilup ratio, V/B, was not specified, we cannot directly calculate L/V, which is the slope of the bottom operating line. Instead, we need to utilize the condition of the feed to determine flow rates in the stripping section. The same procedure used with the Lewis method can be used here. The feed quality, q. 

The on-line flush takes place when the RO skid is returned to service. The objective of the flush is to remove particulates and salts that have settled on the membrane surface while the skid was off line as well as to bring down the concentration of the RO permeate. Figure 13.2 shows the concentration of the RO permeate as a function of flush time after stand-by (assumes a feed water conductivity of 250 micro Siemens per centimeter). Typically, pretreated feed water is used for the flush there is no need to use higher-quality water for this flush. Pressure is generally at nominal operating condition, and any permeate that is generated is sent to drain. 

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