Continuous drum dryer and methods of use thereof
The present disclosure provides for a continuous drying apparatus and a method of using the apparatus in the preparation of dried solids from slurries. The methods and apparatus are useful for the production of fine chemicals and pharmaceuticals, particularly using Integrated Continuous Manufacturing (ICM), but can also be integrated with other manufacturing processes, such as batch and semi-continuous processes.
1. A continuous drying apparatus, comprising:
a pair of rotatable drums 1101 arranged in parallel to their axes of rotation, separated by a gap 1410 , and having drum roller drive assembly 1200 , said pair of rotatable drums 1101 comprising:
an evaporative surface 1110 for receiving a slurry; and
at least one heating element 1102 ;
a drum gap adjustment assembly 1400 comprising a load cell sensor and a controller configured to continuously adjust said gap 1410 during operation to maintain a constant pressure between the surfaces of said pair of rotatable drums 1101 , thereby controlling particle size;
a pair of scrapers 1301 for removing a dried solid from said evaporative surface 1110 of said rotatable drums 1101 ;
a housing 1600 capable of operation at a reduced pressure;
an outlet 1610 ; and
a slurry inlet 1607 .
2. The apparatus of claim 1 , wherein said gap 1410 is adjustable between about 25 micrometers to 2.5 millimeters (mm).
3. The apparatus of claim 2 , wherein said gap 1410 is adjustable in increments, wherein each increment is at least 0.01 mm.
4. The apparatus of claim 1 , wherein said slurry comprises 80 wt % solid to 1 wt % solid in a liquid.
5. The apparatus of claim 1 , wherein said heating element 1102 is selected from the group consisting of a conductive heater, a convective heater, a thermoelectric heater, a Peltier heater, an air heater, recirculating heating fluid, steam, infrared, RF, and combinations thereof.
6. The apparatus of claim 1 , further comprising at least one vibrator 1504 for conveying said dried solid from said housing 1600 .
7. The apparatus of claim 1 , further comprising a mill.
8. A method of continuously drying a slurry using a continuous drying apparatus comprising:
providing a slurry comprising a solid and a carrier liquid to a slurry inlet 1607 of a continuous drying apparatus comprising:
a pair of rotatable drums 1101 arranged in parallel to their axes of rotation, separated by a gap 1410 , and having drum roller drive assembly 1200 , said pair of rotatable drums 1101 comprising
an evaporative surface 1110 for receiving a slurry and at least one heating element 1102 ;
a pair of scrapers 1301 for removing a dried solid from said evaporative surface 1110 of said rotatable drums 1101 ;
a housing 1600 capable of operation at a reduced pressure;
an outlet 1610 ; and
a slurry inlet 1607 ;
heating said pair of rotatable drums 1101 to a first temperature;
rotating said pair of rotatable drums 1101 at a rotation rate;
drying said slurry to produce a cake and an evaporate;
scraping said cake from said pair of rotatable drums 1101 ;
collecting said cake as a dried solid; and
passing said dried solid through said outlet 1610 .
9. The method of claim 8 , wherein said slurry further comprises polymer dissolved in said carrier liquid of said slurry at 10% weight polymer/weight solid or less.
10. The method of claim 8 , further comprising preparing a powder from said cake, wherein said powder is prepared by providing a gap 1410 of between 25 micrometers (μm) to 1 millimeter (mm).
11. The method of claim 9 , wherein said continuous drying apparatus includes a mill and said dried solid is prepared by milling.
12. The method of claim 8 , further comprising applying vibration to said housing 1600 to collect said dried solid.
13. The method of claim 8 , wherein said evaporate is separated from said dried solid by passing said evaporate and said dried solid through a cyclonic separator 1502 .
14. The method of claim 8 , wherein said slurry comprises about 80 wt % solid to about 1 wt % solid in said carrier liquid.
15. The method of claim 8 , wherein the residence time of said slurry in said apparatus is less than about 1 hour.
16. The method of claim 8 , wherein said slurry is provided at a volumetric flow rate between about 3,000 L/min and about 1 mL/min.
17. The method of claim 8 , wherein said evaporative surface 1110 of said drums 1101 is heated to a temperature between 25° C. to 150° C.
18. A method of drying/wet granulation using a continuous drying apparatus comprising:
providing a slurry comprising a solid and a carrier liquid having a dissolved polymer to a slurry inlet 1607 of a continuous drying apparatus comprising:
a pair of rotatable drums 1101 arranged in parallel to their axes of rotation, separated by a gap 1410 , and having drum roller drive assembly 1200 , said pair of rotatable drums 1101 comprising
an evaporative surface 1110 for receiving a slurry and at least one heating element 1102 ;
a pair of scrapers 1301 for removing a dried solid from said evaporative surface 1110 of said rotatable drums 1101 ;
a housing 1600 capable of operation at a reduced pressure;
an outlet 1610 ; and
a slurry inlet 1607 ;
heating said pair of rotatable drums 1101 to a first temperature;
rotating said pair of rotatable drums 1101 at a rotation rate;
drying said slurry to produce a granulated dried material;
collecting said granulated dried material; and
passing said granulated dried material through said outlet 1610 .
19. The method of claim 18 , wherein said carrier liquid comprises said dissolved polymer at 10% weight polymer/weight solid or less.
20. The method of claim 18 , wherein said granulated dried material is prepared by providing a gap 1410 of between 25 micrometers (μm) to 1 millimeter (mm).
21. The apparatus of claim 1 , wherein said housing 1600 capable of operation at a reduced pressure maintains a vacuum below 1×10 5 Pascal (Pa).