Splitter with multi-stage heat pump compressor and inter-reboiler

A method for separating a first material from a mixture of the first material and a second material, the method comprising:

• introducing the mixture into a column through a feed inlet disposed between a top and a bottom of the column,
• exposing material from the column below the feed inlet to an intermediate reboiler heat exchanger,
• exposing bottoms material from the column to a bottoms reboiler heat exchanger,
• circulating overhead vapor taken from the top of the column through first and second overhead loops, the first overhead loop connecting the overhead outlet to a first heat pump compressor, the second overhead loop connecting the overhead outlet to a second heat pump compressor,
• compressing overhead vapor in the first overhead loop and circulating said compressed overhead vapor through the intermediate reboiler heat exchanger to heat the intermediate material exposed to the intermediate reboiler,
• compressing overhead vapor in the second overhead loop and circulating said compressed overhead vapor through the bottoms reboiler heat exchanger to heat the bottoms material exposed to the bottoms reboiler.

A method for separating propylene from a mixture of the propylene and propane, the method comprising:

• introducing the mixture into a column through a feed inlet disposed between a top and a bottom of the column,
• exposing material from the column and below the feed inlet to an intermediate reboiler heat exchanger,
• exposing material from the bottom of the column to a bottoms reboiler heat exchanger,
• circulating overhead vapor taken from the top of the column through first and second overhead loops, the first overhead loop connecting the overhead outlet to a first heat pump compressor, the second overhead loop connecting the first overhead loop to a second heat pump compressor,
• compressing overhead vapor in the first overhead loop and circulating said compressed overhead vapor through an intermediate reboiler heat exchanger to heat and at least partially vaporize the material from the column exposed to the intermediate reboiler heat exchanger,
• compressing overhead vapor in the second overhead loop and circulating said compressed overhead vapor through the bottoms reboiler heat exchanger to heat and at least partially vaporize the material from the column exposed to the bottoms reboiler heat exchanger,
• withdrawing propylene from the first overhead loop, and
• withdrawing propane from the second overhead loop.