US Patent 7172686 Method of increasing distillates yield in crude oil distillation

Methods of separating components of a mixture, such as crude oil, are disclosed which increase the yield of individual components while decreasing the yield of residue. In one method, a heated mixture is fed to a column, a vapor stream is withdrawn from the column and separated, and a portion of the vapor stream is recycled back to the column. In another method, a mixture is separated into streams composed substantially of components having light, intermediate or heavy molecular weight and/or low, intermediate or high boiling point, respectively, and the streams are fed into the column at different positions. In both methods, individual light, intermediate and/or heavy molecular weight and/or low, intermediate and/or high boiling point component streams are then selectively withdrawn from the column.