Abstract:
The present invention relates to a system for one pot solids recovery from solutions, slurries, emulsions, dispersions, gels, semisolids, and their like. Further the system can be used for controlled concentration of solutions, slurries, emulsions, dispersions, gels, semisolids, and their like to enable easy to operate cost effective energy efficient processes. The system is so constructed to enhance the contact between the liquid medium and the gaseous medium used in the process for effective heat transfer. The system can be used for controlled concentration and/or recovery of substantially dry solids in applications related to foods, nutraceuticals, natural products, pharmaceuticals, chemicals, etc.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to a system for one pot solids recovery from solutions, slurries, gels, semisolids, and their like. Further the system can be used for controlled concentration of solutions, slurries, gels, semisolids, and their like. 
       BACKGROUND OF THE INVENTION 
       [0002]    Recovery of solids from solutions, slurries, dispersions, emulsions, gels, semisolids, and their like involves the removal of the solvent and/or the carrier medium by diverse processes that involve evaporation, reverse osmosis, ultrafiltration, pervaporation, freeze concentration, clathration etc. Such processes are generally carried out using various types of equipments such as spray driers, drum driers, freeze driers, foam-mat, fluid bed driers, etc. 
         [0003]    Spray driers are routinely used for recovery of solids from solutions/slurries. Similarly fluid bed driers are routinely used to dry wet solids but cannot be used for recovery of solids from solutions, dispersions, slurries, emulsions, gels, semisolids and their like. 
         [0004]    The challenges in technologies related to the treatment of solutions, dispersions, slurries, emulsions, gels, semisolids and their like for the recovery of substantially dry solids are in providing cost effective equipments/systems that enable easy to operate energy efficient processes. The present inventions address this technology gap. 
       DEFINITION 
       [0005]    The term “substantially dry solids” when used herein shalt mean the “loss on drying” to be less than 10% by weight of the solids, preferably less than 5% by weight of the solids, more preferably less than 2% by weight of the solids and most preferably less than 1% by weight of the solids depending on the type and nature of the material and the method used for its determination. 
       OBJECTS OF THE INVENTION 
       [0006]    The main object of the invention is to provide a solid recovery system for the recovery of substantially dry solids from solutions, dispersions, slurries, emulsions, gels, semisolids and their like that enables easy to operate cost effective energy efficient processes. 
         [0007]    Another object of the invention is to provide a system for a single pot process for the concentration of solutions, slurries, dispersions, emulsions, gels, semisolids, and further substantially drying the solids for their recovery. 
         [0008]    Another object of the invention is to provide a system to enhance the contact between the liquid phase and the gaseous medium used in the process for effective heat transfer for controlled concentration and/or recovery of substantially dry solids from solutions, slurries, dispersions, emulsions, gels, semisolids, and their like. 
         [0009]    Yet another object of the invention is to provide a method of using the said system for controlled concentration and/or rec overy of substantially dry solids in applications related to foods, nutraceuticals, natural products, pharmaceuticals, chemicals, etc. 
         [0010]    Thus in accordance with the invention, the system comprises, 
         [0011]    a container module, gas pressurizing means, vapor extraction means, and optional filters, 
         [0012]    wherein the said container module comprises 
         [0013]    first container that is provided with perforated base for passage of pressurized gas, 
         [0014]    second container disposed in the said first container so as to form a first continuous annular space on the sides as well as to define space between the base of the said first container and base of the said second container to enable gas flow, 
         [0015]    wherein the said first annular space is closed on the top, wherein the base of the said second container has a substantially flat bottom, 
         [0016]    third container disposed inside the said second container to define a second continuous annular space on the sides as well as to define the space between the base of the said third container and the base of the said second container 
         [0017]    wherein the said second annular space is closed from top, the base of the said third container being provided with perforations or passages; 
         [0018]    the base of the said first container is operably connected with the outlet of the pressurized gas source, 
         [0019]    the said container module is integrated in a housing with vapor extraction means at the top and an optional filter. 
         [0020]    The liquid medium (solution/dispersion/emulsion/slurry/gel/semisolid and their like) is filled in the said third container, and pressurized gas (for example air) is made to flow from the base of the said first container through the said first annular space into the said second annular space and further from the passages in the base of the said third container to mix with the liquid medium, causing the solvent to evaporate and further dry the formed solids in the same system for recovery. 
         [0021]    In an embodiment of the process, the hot pressurized gas such as air of appropriate temperature and humidity may be used depending on the nature of the solvent/carrier in the solution, slurry, gel, dispersion, emulsion, semisolid etc. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Features and advantages of the invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings. 
         [0023]    The schematic of the system of the invention is illustrated in  FIG. 1 . It comprises of a container module  10 , gas pressurizing means  11 , expansion chamber  12 , filter housing  13 , vapor exhaust (extraction) port  14 . 
         [0024]    The schematic of the container module  10  is illustrated in  FIG. 2 . It comprises of first container  1  that is provided with perforated base or perforated gas distribution plate  20  for gas passage. The flow path of the gas such as pressurized air is indicated in the  FIG. 2  by arrow  21  for better understanding. The second container  2  is disposed in the said first container  1  so as to define first annular space  22  between first and the second container as well as to define space  23  between the base  20  of the said first container and base  24  of the said second container  2 . 
         [0025]    The said first annular space  22  is closed on the top side  25  as illustrated in the  FIG. 2 . The base  24  of the said second container  2  is substantially flat or is provided with a substantially flat plate. The third container  3  is disposed inside the said second container  2  to define second annular cavity/space  26  as well as to define the space  29  between the base  28  of the said third container and the base  24  of the said second container. The said second annular space  26  is closed from top side  27  as illustrated in the  FIG. 2 . The base  28  of the said third container  3  is provided with a set of perforations/passages or is provided with a gas distribution plate with a set of perforations/passages. 
         [0026]    In one of the embodiments, the said first, second and third containers  1 ,  2  and  3  respectively are of frusto-conical geometry. 
         [0027]    The base  20  of the said first container  1  is operably connected with the outlet of the gas pressurizing means such as compressor or blower. The said container module  10  is operably connected to the expansion chamber  12  and further to the filter housing  13  as depicted in  FIG. 1 . 
         [0028]    In operation, the solution/dispersion/emulsion/slurry/gel/semisolid and their like is filled in the said third container  3 . The pressurized gas flows from the base  20  of the said first container  1  through the said space  23  and further through the first annular space  22  into the said second annular space  26 . It further passes from the passages in the base  28  of the said third container  3  to mix with the solution/dispersion/emulsion/slurry/gel/semisolid and their like, cause the solvent to evaporate and the dry the resulting solids for final recovery. 
         [0029]    In one of the embodiments, the said third container  3  is provided with a set of inclined passages configured to distribute gas in the bulk of the liquid medium (solution/dispersion/emulsion/slurry/gel/semisolid and their like) to create turbulence for enhancement of contact between the gas and the liquid medium for improved heat transfer. In one of the variants of this embodiment, the passages are inclined to the horizontal at 15° to 85°, preferably 25° to 75°. 
         [0030]    One of the configurations of the said passages in the said base  28  is depicted in  FIG. 3 . As an illustration, only quarter of the gas distribution plate is indicated with the configuration of the passages (individual passage is indicated by numeral  50 ). The said passages may be of any shape such as oval, flat oval, rectangular, circular, square, elliptical, or combinations thereof. The ratio of thickness of the said base  28  to the length of the passage is in the range of 0.250 to 0.999. 
         [0031]    The ratio of total area of the passages to the area of the base is in the range of 0.01 to 0.50, preferably 0.03 to 0.30, more preferably 0.05 to 0.10. 
         [0032]    In an embodiment of the invention, the said passages are provided with internal serrations to provide swirling motion to the gas passing through it. 
         [0033]    In yet another embodiment the passages provided in the base of the said third container are of diverse cross section such as round, oval, flat oval, rectangular, square etc. 
         [0034]    In yet another embodiment plurality of passages are provided on the sides of the said third container. 
         [0035]    In another embodiment there are more than three containers disposed so as to create more than two annular spaces between them. 
         [0036]    The invention further provides non-limiting examples. 
       EXAMPLE 1 
       [0037]    A solution of 6 kg of sucrose was prepared in 25 kg of water and 5 kg of acetone and filled in third container. The third container was provided with gas distribution plate with passages inclined to the horizontal at 55°. The system was preheated with a stream of hot and dehumidified air. Pressurized hot air was introduced into the system from the bottom of first container and process was run for about 1.5 hours with exhaust kept on to remove the evaporated solvent vapors from the system. The inlet air temperature was about 60° C. to 90° C. resulting in bed temperature of about 30° C. to 55° C. and outlet air/vapor temperature of about 30° C. to 45° C. The solution gradually got concentrated with the emergence of the solids which got dried as a fluidized bed till the solvent was completely removed and the substantially dry solids were obtained. The solid material was removed and weighed. The yield of the process was 96.3% and the moisture content in the solids was ˜0.7%. 
       EXAMPLE 2 
       [0038]    5 kg of non-pareil seeds was added to 25 kg of purified water. The mixture was stirred to obtain a dispersion which was charged in the third container. The third container was provided with gas distribution plate with passages inclined to the horizontal at 55° The process described in example 1 was carried out. At the end of the process, solid material was removed and weighed. The yield of the process was ˜95% and the moisture content in the solids was less than 1.5%. 
       EXAMPLE 3 
       [0039]    0.400 kg of starch was added to 1.5 kg of isopropyl alcohol. The mixture was stirred to obtain a dispersion which was filled in third container. The third container was provided with a gas distribution plate with passages inclined to the horizontal at 25°. The system was preheated with a stream of hot and dehumidified air. Pressurized hot air was introduced into the system from the bottom of first container and process was run for about 1 hours with exhaust kept on to remove the evaporated solvent vapors from the system. The inlet air temperature was about 60° C. resulting in bed temperature of about 15° C. to 55° C. and outlet air/vapor temperature of about 20° C. to 45° C. The solution gradually got concentrated with the emergence of the solids which got dried as a fluidized bed till the solvent was completely removed and the substantially dry solids were obtained. The solid material was removed and weighed. The yield of the process was ˜81% and the moisture content in the solids was about 5.2%. 
       EXAMPLE 4 
       [0040]    0.300 kg of povidone K30 was added to 0.13 kg of purified water. The mixture was stirred to obtain a gel. The third container was provided with gas distribution plate with passages inclined to the horizontal at 75°. Purified talc (0.007 kg) was sprinkled (applied) to the inner walls of third container and the upper surface of gas distribution plate. The prepared gel was filled in third container. The system was preheated with a stream of hot and dehumidified air. Pressurized hot air was introduced into the system from the bottom of first container and process was run for about 4 hours with exhaust kept on to remove the evaporated solvent vapors from the system. The inlet air temperature was about 65° C. to 85° C. resulting in bed temperature of about 35° C. to 70° C. and outlet air/vapor temperature of about 40° C. to 65° C. The solution gradually got concentrated with the emergence of the solids which got dried as a fluidized bed till the solvent was completely removed and the substantially dry solids were obtained. The solid material was removed and weighed. The yield of the process was 90% and the moisture content in the solids was about 2.8%. 
       EXAMPLE 5 
       [0041]    0.400 kg of lactose was added to 4.89 kg of purified water. The mixture was stirred to obtain a solution which was filled in third container. The third container was provided with gas distribution plate with passages inclined to the horizontal at 35°. The system was preheated with a stream of hot and dehumidified air. Pressurized hot air was introduced into the system from the bottom of first container and process was run for about 3.5 hours with exhaust kept on to remove the evaporated solvent vapors from the system. The inlet air temperature was about 45° C. to 90° C. resulting in bed temperature of about 25° C. to 75° C. and outlet air/vapor temperature of about 30° C. to 60° C. The solution gradually got concentrated with the emergence of the solids which got dried as a fluidized bed till the solvent was completely removed and the substantially dry solids were obtained. The solid material was removed and weighed. The yield of the process was 91.75% and the moisture content in the solids was 0.62%. 
         [0042]    The invention described demonstrates the effectiveness of the designed systems that enables a one pot solids recovery from solutions, emulsions, dispersions, slurries, gels, semisolids, and their like. Further the equipment and the process can be used for controlled concentration of solutions, slurries, dispersions, emulsion, semisolids, and gels and materials of their like.