Solid hollow fiber cooling crystallization systems and methods

Abstract

A solid hollow fiber cooling crystallizer and method for crystallizing aqueous and organic solutions are provided. The solid hollow fiber crystallizer (SHFC) for carrying out cooling crystallization of inorganic/organic microsolutes/macrosolutes from solution generally includes a bundle of non-porous hollow fibers mounted within a shell where a feed solution for crystallization flows through the lumen side of the hollow fibers and a cooling solution flows through the shell side to form nuclei and subsequently crystals in the feed solution at a temperature below its saturation temperature. The solid hollow fiber crystallizer may be combined with a mixing device, such as a completely stirred tank or static mixer, to further effectuate crystallization. The solid hollow fiber crystallizer may be operated in a number of modes including feed recycle mode, once through mode, SHFC-in-line static mixer in series mode, and SHFC-CST in series mode. The advantages of solid hollow fiber cooling crystallization in comparison to conventional crystallization processes include improved temperature control between crystallizing solution and coolant, higher nucleation rates, improved control of crystal size and crystal size distribution, smaller crystal size, capability for decoupling crystal nucleation and crystal growth, decreased fouling of process equipment, and improved process scale-up.

1 . A non-porous solid hollow fiber crystallizer (SHFC) system for carrying out crystallization of solute from solution comprising: 
 (a) a shell including inlet and outlet openings to facilitate ingress and egress of fluids, and    (b) a plurality of non-porous hollow fibers mounted within said shell, wherein each of said plurality of fibers defines a lumen side and a shell side,    wherein nuclei and crystals are formed in a feed solution that is fed through said lumen side or said shell side of said plurality of fibers, said nuclei and crystals being formed at a temperature below a saturation temperature associated with said feed solution through heat transfer with a cooling solution in flow on an opposite side of said plurality of fibers.    
   
   
       2 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , further comprising a mixing device downstream of said shell and in fluid communication with said feed solution.  
   
   
       3 . The solid hollow fiber crystallizer (SHFC) system of  claim 2 , wherein said downstream mixing device is effective to control crystal size distribution of said feed solution.  
   
   
       4 . The solid hollow fiber crystallizer (SHFC) system of  claim 2 , wherein said mixing device is selected from the group consisting of a completely stirred tank (CST) and an in-line static mixer.  
   
   
       5 . The solid hollow fiber crystallizer (SHFC) system of  claim 2 , further comprising: 
 (a) means for storing said feed solution upstream of said shell,    (b) means for continuously circulating said feed solution through said lumen side or said shell side of said plurality of fibers,    (c) means for continuously circulating a cooling solution through said shell side or lumen side of said plurality of fibers,    (d) means for chilling said cooling solution below said saturation temperature associated with said feed solution, and    (f) means for filtering said nuclei and crystals from said feed solution.    
   
   
       6 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , further comprising apparatus adapted to support at least one operation selected from the group consisting of: (i) feed recycle operation mode, (ii) once through operation mode, (iii) SHFC-in-line static mixer in series operation mode, (iv) SHFC-CST series mode of operation, and (v) a combination or sub-combination of the foregoing operation modes.  
   
   
       7 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , wherein said feed solution is aqueous or organic.  
   
   
       8 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , wherein said plurality of non-porous hollow fibers are fabricated from a polymeric or ceramic material.  
   
   
       9 . The solid hollow fiber crystallizer (SHFC) system of  claim 8 , wherein said plurality of non-porous hollow fibers is fabricated from a polymeric material selected from the group consisting of polypropylene, polyethersulfone (PES), polyetheretherketone (PEEK), a polyimide, polyphenyl sulfide (PPS), polyethylene, polytetrafluoroethylene (PTFE), polysulfone (PS) and poly-4-methyl-1-pentene (PMP).  
   
   
       10 . The solid hollow fiber crystallizer (SHFC) system of  claim 8 , wherein said plurality of non-porous hollow fibers is fabricated from a ceramic material selected from the group consisting of alumina, silica and glass.  
   
   
       11 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , wherein said plurality of fibers are selected from the group consisting of symmetric hollow fibers and asymmetric hollow fibers with a non-porous surface on an internal diameter thereof.  
   
   
       12 . The solid hollow fiber crystallizer (SHFC) system of  claim 1 , wherein said plurality of non-porous hollow fibers is helically oriented within said shell.  
   
   
       13 . The solid hollow fiber crystallizer (SHFC) device of  claim 1 , wherein said cooling solution is circulated in countercurrent, cocurrent or cross flow mode relative to said feed solution.  
   
   
       14 . A method of forming nuclei and subsequently crystals in a feed solution, comprising the steps of: 
 (a) conveying said feed solution into a solid hollow fiber crystallizer (SHFC) system, said solid hollow fiber crystallizer system including a plurality of non-porous hollow fibers mounted within a shell and said feed solution being conveyed to either a lumen side or a shell side of said plurality of non-porous hollow fibers;    (b) conveying a cooling solution into said solid hollow fiber crystallizer, said cooling solution being conveyed to an opposite side of said plurality of non-porous hollow fibers as compared to said feed solution; and    (c) cooling said feed solution below its saturation temperature to form nuclei and crystals.    
   
   
       15 . The method of  claim 14 , wherein said feed solution is selected from the group consisting of an aqueous solution and an organic solution.  
   
   
       16 . The method of  claim 14 , wherein said feed solution includes an inorganic or organic solute.  
   
   
       17 . The method of  claim 14 , wherein said feed solution includes at least one of microsolutes and macrosolutes.  
   
   
       18 . The method of  claim 14 , further comprising the step of subjecting said feed solution that contains nuclei and crystals to filtration.  
   
   
       19 . The method of  claim 14 , further comprising the step of recycling said cooled feed solution back through said solid hollow fiber crystallizer system.  
   
   
       20 . The method of  claim 14 , further comprising the steps of: 
 (a) conveying said cooled feed solution into a mixing device,    (b) controlling crystal size distribution in said cooled feed solution within said mixing device,    (c) conveying a cooled feed solution from said mixing device, and    (d) filtering nuclei and crystals from said cooled feed solution.    
   
   
       21 . The method of  claim 14 , wherein said hollow fiber crystallizer system comprises a bundle of non-porous polymeric or ceramic hollow fibers mounted within said shell.  
   
   
       22 . The method of  claim 21 , wherein said hollow fiber crystallizer system includes a bundle of non-porous hollow fibers fabricated from a polymeric material selected from the group consisting of polypropylene, polyethersulfone (PES), polyetheretherketone (PEEK), a polyimide, polyphenyl sulfide (PPS), polyethylene, polytetrafluoroethylene (PTFE), polysulfone (PS) and poly-4-methyl-1-pentene (PMP).  
   
   
       23 . The method of  claim 21 , wherein said hollow fiber crystallizer system includes a bundle of non-porous hollow fibers fabricated from a ceramic material selected from the group consisting of alumina, silica and glass.  
   
   
       24 . The method of  claim 14 , wherein a temperature difference between said feed solution temperature and said chilled cooling solution is less than or equal to 2° C.  
   
   
       25 . The method of  claim 14 , further comprising conveying said cooled feed solution to a mixing device selected from the group consisting of a completely stirred tank and an in-line static mixer.  
   
   
       26 . The method of  claim 25 , wherein said solid hollow fiber crystallizer (SHFC) system is effective to cause crystal nucleation, and said mixing device is effective to cause crystal growth.  
   
   
       27 . The method of  claim 14 , wherein said plurality of hollow fibers is oriented in a helix within said shell.  
   
   
       28 . The method of  claim 14 , wherein said feed solution includes seed crystals and wherein said solid hollow fiber crystallizer (SHFC) system is effective to grow said seed crystals.