Ultrafiltration 101 4.2.2 Yield Ultrafiltration is now being used to concentrate and recover some very valuable com- pounds. The yield or recovery of a component is a very important variable, as it will strongly influence the economics of the process. present in the feed, which is retained in the concentrate. For recovery of compollco. a The yield of a component is defined as the fraction of that component, origina mportant to have a high yield. However, when washing out components, such as toxins, the yield should be lov For a batch process, it can be shown that the yield of any component depends upon the concentration factor and rejection Concentration factor and the yield (n is given by Y= mass component in final concentrate=vacc (4.3) mass substance in feed where Vc and Ve are the volumes of feed and concentrate and cc and cF are the concen trations in the concentrate and feed If we now consider a batch concentration process depicted by Fig. 4.2, where permeate is removed and the retentate is recycled At any instance let the volume of the concentrate V and the concentration of the component of interest =c Permeate Fig. 4.2. Batch concentration process for yield calculation Let the removal of a small volume of permeate(dv), result in a change of concentration A mass balance on the component will give the following equation (feed)(concentrate) rmeate Rejection (R)=(c-Cp)Ultrafiltration 101 4.2.2 Yield Ultrafiltration is now being used to concentrate and recover some very valuable com￾pounds. The yield or recovery of a component is a very important variable, as it will strongly influence the economics of the process. The yield of a component is defined as the fraction of that component, originally present in the feed, which is retained in the concentrate. For recovery of components it is important to have a high yield. However, when washing out components, such as toxins, the yield should be low. For a batch process, it can be shown that the yield of any component depends upon the concentration factor and rejection. Concentration factor cf) = vF/vC (4.2) and the yield (Y) is given by mass component in final concentrate - VCCC Y= -- mass substance in feed VFCF (4.3) where V, and VF are the volumes of feed and concentrate and cc and CF are the concen￾trations in the concentrate and feed. If we now consider a batch concentration process depicted by Fig. 4.2, where permeate is removed and the retentate is recycled: At any instance let the volume of the concentrate = V and the concentration of the component of interest = c in" f" Permeate CP Fig. 4.2. Batch concentration process for yield calculation. Let the removal of a small volume of permeate (dV), result in a change of concentration (dc) * A mass balance on the component will give the following equation: VC = (V-dV)(c-dc) + cpdV (feed) (concentrate) (permeate) Rejection (R) = (c - cp )/c