The absence of any significant azeotrope between ethanol and butenes results in unreacted ethanol being recovered primarily with the ETBE product. As indicated above, the presence of an azeotrope between ethanol and water also results in some water being recycled to the reaction stage if is attempted to recover the unreacted ethanol from the distillate. There is much lower load on the recovery equipment due to the lower concentration of ethanol in the distillate. In fact, it is feasible, under some refinery conditions, to eliminate the ethanol recovery equipment altogether, resulting in the simplified flow diagram shown in Figure 6.3.
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