Purification of fluid compounds utilizing a distillation - membrane separation process

A continuous process for separation of purified products from a fluid mixture by utilization of an integrated distillation and membrane separation apparatus which process comprises:

• providing a separation apparatus comprising
• (a) a fractional distillation column having an overhead vapor outlet in flow communication with a compressor, and an external heat transfer surface having one side disposed to contact fluid at the bottom of the column and the opposite side to contact compressed overhead vapor,
• (b) the compressor in fluid communication with means for proportioning compressed vapor between the heat transfer surface, a reflux condenser, and a cooler, said cooler is in flow communication with a per-selective membrane device,
• (c) the membrane device comprising a solid perm-selective membrane which under suitable differential of a driving force exhibits a permeability of at least 0.1 Barrer, channels having at least one inlet and one outlet for flow of fluid in contact with a first side of the membrane, and contiguous with the opposite side thereof a permeate chamber having at least one outlet for flow of permeate, and
• (d) Means for flow communication between the opposite side of the heat transfer surface and the fractional distillation column,
• Separating by fractional distillation a feedstock comprising a fluid mixture including a low-boiling point component and a high boiling point component, and thereby provide a vapor stream enriched in the low-boiling point component to the compressor;
• compressing the overhead vapor, and distributing portion thereof between the heat transfer surface, the reflux condenser, and the membrane device;
• and
• Separating from the stream distributed into the membrane device a permeate and non-permeate stream by selective permeation while controlling enthalpy of the distributed stream by controlling temperature thereof, and thereby maintain Membrane Efficiency Index of the non-permeate effluent stream within a range from about 0.5 to 1.5;
• and
• directing fluid from the opposite side of the heat transfer surface to the fractional distillation column.