Heat Pump for High Purity Bottom Product

Abstract

An apparatus for reducing the energy consumption of a distillation column is disclosed. The apparatus draws off an intermediate vapor stream from the rectification section of the distillation column, where the vapor stream is compressed and used to reboil a portion of the bottoms stream. The compressed vapor stream transfers energy to the bottoms stream, thereby condensing a portion of the vapor stream while vaporizing the bottoms stream.

1 . An apparatus for the distillation separation of a first component from a mixture comprising:
 a distillation column comprising a rectifying section having an outlet for an overhead vapor stream, a stripping section having an outlet for a bottoms liquid stream, and feed section having a feed inlet and disposed between the rectifying section and the stripping section;   a bottoms reboiler section for reboiling the bottoms liquid stream entering from the stripping section;   an overhead condensing section for condensing the overhead vapor stream from the rectifying section;   a side vapor draw from the rectifying section;   a heat pump compressor having an inlet in fluid communication with the side vapor draw, and an outlet; and   a second reboiler heat exchanger having a fluid side in fluid communication with the bottoms stream from the stripping section, and having a vapor side in fluid communication with the outlet from the heat pump compressor.   
   
   
       2 . The apparatus of  claim 1  further comprising a second heat pump compressor having an inlet in fluid communication with the overhead vapor stream, and an outlet thereby generating an overhead compressed vapor stream. 
   
   
       3 . The apparatus of  claim 2  wherein the bottom reboiler section comprises a heat exchanger having fluid side in fluid communication with the bottoms stream from the stripping section, and having a vapor side in fluid communication with the overhead compressed vapor stream. 
   
   
       4 . The apparatus of  claim 2  further comprising a condenser having an inlet in fluid communication with the second heat pump outlet, and for condensing a portion of the overhead compressed vapor stream. 
   
   
       5 . The apparatus of  claim 4  wherein the condenser is a trim condenser. 
   
   
       6 . The apparatus of  claim 2  further comprising a vapor-liquid separation tank for separating having an inlet in fluid communication with the rectifying section outlet, and an outlet in fluid communication with the second heat pump compressor inlet. 
   
   
       7 . The apparatus of  claim 1  further comprising a third reboiler for reboiling additional liquid from the bottoms stream. 
   
   
       8 . The apparatus of  claim 1  wherein the side vapor draw is positioned above the lowest tray of the rectifying section. 
   
   
       9 . The apparatus of  claim 1  further comprising a side inlet to the rectifying section and wherein the heat pump compressor outlet is in fluid communication with the side inlet to the rectifying section. 
   
   
       10 . An apparatus for the distillation separation of a first component from a mixture comprising:
 a distillation column comprising a rectifying section having an outlet for an overhead vapor stream, a stripping section having an outlet for a bottoms liquid stream, and feed section having a feed inlet and disposed between the rectifying section and the stripping section;   an overhead condensing section for condensing the overhead vapor stream from the rectifying section;   an overhead heat pump compressor having an inlet in fluid communication with the overhead vapor stream, and an outlet thereby generating an overhead compressed vapor stream;   a bottoms reboiler section for reboiling the bottoms liquid stream entering from the stripping section, wherein the bottom reboiler section comprises a heat exchanger having fluid side in fluid communication with the bottoms stream from the stripping section, and having a vapor side in fluid communication with the overhead compressed vapor stream;   a side vapor draw from the rectifying section;   a side inlet in the rectifying section;   a second heat pump compressor having an inlet in fluid communication with the side vapor draw, and an outlet in fluid communication with the side inlet to the rectifying section; and   a second reboiler heat exchanger having a fluid side in fluid communication with the bottoms stream from the stripping section, and having a vapor side in fluid communication with the outlet from the second heat pump compressor.   
   
   
       11 . The apparatus of  claim 10  further comprising a trim condenser having an inlet in fluid communication with the overhead heat pump outlet, and for condensing a portion of the overhead compressed vapor stream. 
   
   
       12 . The apparatus of  claim 10  further comprising a vapor-liquid separation tank for separating having in inlet in fluid communication with the rectifying section outlet, and an outlet in fluid communication with the overhead heat pump compressor inlet. 
   
   
       13 . The apparatus of  claim 10  further comprising a third reboiler in fluid communication with the bottoms stream from the stripping section, and having a vapor outlet in fluid communication with the bottom of the stripping section of the distillation column. 
   
   
       14 . An apparatus for the distillation of a first component from a mixture comprising:
 a distillation column comprising a rectifying section having an outlet for an overhead vapor stream, a stripping section having an outlet for a bottoms liquid stream, and feed section having a feed inlet and disposed between the rectifying section and the stripping section;   a side draw;   a first bottoms reboiler section comprising a means for reducing the pressure in the bottoms liquid stream, a first reboiler having a liquid side in fluid communication with the bottoms liquid stream and a vapor side in fluid communication with the overhead vapor stream, and a first heat pump compressor in fluid communication with the first reboiler liquid side; and   a vapor-liquid separation drum having an inlet in fluid communication with the first reboiler vapor side and an outlet in fluid communication with the top of the rectifying section.   
   
   
       15 . The apparatus of  claim 14  wherein the side draw is a vapor side draw from the rectifying section. 
   
   
       16 . The apparatus of  claim 15  further comprising a second reboiler having a liquid side in fluid communication with the bottoms liquid stream and a vapor side in fluid communication with the side vapor from the side vapor draw, and a second heat pump compressor in fluid communication with the second reboiler liquid side. 
   
   
       17 . The apparatus of  claim 14  further comprising a second means for reducing pressure in the bottoms liquid stream. 
   
   
       18 . The apparatus of  claim 14  wherein the means for reducing pressure is a Joule-Thompson type valve. 
   
   
       19 . The apparatus of  claim 14  wherein the side draw is a liquid side draw from the stripping section. 
   
   
       20 . The apparatus of  claim 19  further comprising a second means for reducing the liquid pressure from the liquid side draw, a second reboiler having a liquid side in fluid communication with the liquid side draw and a vapor side in fluid communication with a portion of the overhead vapor stream, and a second heat pump compressor in fluid communication with the second reboiler liquid side.