Patent ID: 7048833

Claim:
A process for vaporizing an oxygenate-containing feed which comprises: preheating a liquid oxygenate-containing feed containing at least partial non-volatiles and having an initial heat content, to provide a feed of increased heat content comprising a liquid phase and a vapor phase; passing said feed of increased heat content to at least one vapor-liquid disengaging drum to provide i) an overhead fraction comprising vaporized oxygenate-containing stream containing less than about 10 wt % of non-volatiles in said feed plus an equilibrium amount of partial non-volatiles in the feed, and ii) a bottoms fraction comprising a liquid oxygenate-containing stream containing the at least partial non-volatiles derived from said feed which are not in said overhead fraction, and further wherein the boiling point in said at least one vapor-liquid disengaging drum is controlled by varying the total pressure within the at least one vapor-liquid disengaging drum; recovering said overhead fraction; directing said bottoms fraction containing liquid oxygenate-containing stream containing said at least partial non-volatiles through at least one heat exchanger external to said at least one vapor-liquid disengaging drum, wherein heat is added to said liquid oxygenate-containing stream to provide a beat exchanged stream containing vapor phase oxygenate and wherein said at least one heat exchanger comprises a circulating partial vaporizer where circulation of said liquid oxygenate-containing stream through the exchanger is induced by at least one of i) mechanically pumping said liquid oxygenate-containing stream through the heat exchanger and ii) thermosyphon circulation where the weight or density multiplied by height of the liquid oxygenate-containing stream minus total frictional losses being greater than the weight or density multiplied by height of the heat exchanged stream containing vapor phase oxygenate, drives said circulation; and directing said heat-exchanged stream to said at least one vapor-liquid disengaging drum.