ULTRAHIGH EFFICIENCY SPRAY DRYING APPARATUS AND PROCESS

20190232305

16/379127

April 09, 2019

The disclosure relates to ultrahigh efficiency spray drying systems and processes, utilizing induction of localized turbulence in a drying fluid flow stream to produce spray dried product, having particular utility for low temperature spray drying operations. In a specific implementation, a method of processing a spray dryable liquid composition to form a spray dried product includes the steps of: generating a spray of the spray dryable liquid composition; contacting the spray of spray dryable liquid composition in a spray drying contact zone with a stream of primary drying fluid; injecting pressurized secondary drying fluid into the stream of primary drying fluid in the spray drying contact zone at multiple loci thereof to provide localized turbulence at said multiple loci; and recovering the spray dried product from the spray drying contact zone. Systems of the present disclosure are effective in achieving high-rate production of dry powder spray dried products, with substantially reduced capital equipment costs, energy requirements, and operating expenditures.

1. A spray drying system, comprising: (a) a spray drying vessel comprising: (i) an interior volume arranged to receive an atomized spray-dryable material and drying fluid for contacting of the atomized spray-dryable material with the drying fluid in the interior volume; (ii) at least one drying fluid inlet by which the drying fluid is introduced into the interior volume for said contacting; and (iii) a spray-dried material outlet communicating with the interior volume, arranged to discharge spray-dried material and effluent drying fluid from the vessel; (b) an atomizer adapted to receive a spray-dryable material and discharge the atomized spray-dryable material into the interior volume of the vessel for said contacting; (c) turbulators positioned to generate localized turbulence in the drying fluid throughout the interior volume of the vessel; and (d) a process control unit adapted to regulate flow rate of drying fluid into the interior volume and flow rate of the spray-dryable material to the atomizer so that interaction of the drying fluid with the turbulators produces localized turbulence in the drying fluid throughout the interior volume of the vessel.

2. The spray drying system of claim 1, wherein the turbulators and process control unit are adapted to cooperatively provide a turbulence dissipation rate of said localized turbulence in the drying fluid in the interior volume of the vessel that exceeds 25 m2/sec3.

3. The spray drying system of claim 1, wherein the turbulators and process control unit are adapted to cooperatively provide said localized turbulence in the drying fluid in the interior volume of the vessel, wherein said localized turbulence is characterized by a Kolmogorov length that is less than an average particle size of spray dryable material droplets in the atomized spray-dryable material.

4. The spray drying system of claim 1, wherein said process control unit is adapted to regulate temperature of the drying fluid so that the spray drying system operates in a low temperature mode of operation.

5. The spray drying system of claim 1, wherein the turbulators comprise nozzles configured to inject pressurized secondary drying fluid into the interior volume of the vessel.

6. The spray drying system of claim 5, wherein at least some of the nozzles are provided along a wall of the vessel.

7. The spray drying system of claim 5, wherein at least some of the nozzles are provided at a central region of the interior volume of the vessel.

8. The spray drying system of claim 5, wherein said nozzles comprise nozzles provided along a wall of the vessel and nozzles provided at a central region of the interior volume of the vessel.

9. The spray drying system of claim 1, wherein the atomizer comprises at least one selected from among nozzle atomizers, applied charge atomizers, nebulizers, rotary atomizers, and ultrasonic atomizers.

10. The spray drying system of claim 1, comprising a drying fluid source coupled to the at least one drying fluid inlet in drying fluid supply relationship with the spray drying vessel.

11. The spray drying system of claim 10, wherein the drying fluid source is constituted to supply the drying fluid to the at least one drying fluid inlet of the spray drying vessel, the drying fluid comprising air, oxygen-enriched air, oxygen, nitrogen, argon, krypton, neon, helium, or a gas mixture comprising two or more of the foregoing drying fluid species.

12. The spray drying system of claim 10, wherein the drying fluid source is constituted to supply the drying fluid to the at least one drying fluid inlet of the spray drying vessel at temperature below at least one of 120° C., 115° C., 110° C., 100° C., 95° C., 90° C., 85° C., 80° C., 75° C., 70° C., 65° C., 60° C., 55° C., 50° C., 45° C., 40° C., 35° C., 30° C., 25° C., and 20° C., and above freezing temperature of liquid to be volatilized for spray drying of the spray-dryable material.

13. The spray drying system of claim 10, wherein the drying fluid source is constituted to supply the drying fluid to the at least one drying fluid inlet of the spray drying vessel at temperature below 100° C., and above freezing temperature of liquid to be volatilized for spray drying of the spray-dryable material.

14. The spray drying system of claim 1, comprising a spray-dryable material source arranged in spray-dryable material supply relationship to the atomizer.

15. The spray drying system of claim 14, wherein the spray-dryable material source contains spray-dryable material having a viscosity in a range of 500 to 16,000 mPa-s and a solvent content that does not exceed 50% by weight, based on total weight of the spray-dryable material.

16. The spray dryable system of claim 1, comprising a dehumidification assembly arranged to dehumidify the drying fluid so that it is introduced by the at least one drying fluid inlet into the interior volume of the vessel for said contacting, at a relative humidity below 35%.

17. The spray drying system of claim 1, as configured for electrostatic spray-drying.

18. The spray drying system of claim 1, comprising a single step spray drying system.

19. A process for producing a spray-dried material, comprising: generating an atomized spray-dryable material; contacting the atomized spray-dryable material with drying fluid to form spray-dried material; recovering the spray-dried material from the drying fluid; and during said contacting, inducing localized turbulence throughout said drying fluid engaged in said contacting.

20. The process of claim 19, wherein said localized turbulence has a turbulence dissipation rate that exceeds 25 m2/sec3.

21. The process of claim 19, wherein said localized turbulence is characterized by a Kolmogorov length that is less than an average particle size of spray dryable material droplets in the atomized spray-dryable material.

22. The process of claim 19, wherein said localized turbulence is induced at least in part by injecting pressurized secondary drying fluid into said drying fluid engaged in said contacting.

23. The process of claim 19, wherein the drying fluid comprises air, oxygen-enriched air, oxygen, nitrogen, argon, krypton, neon, helium, or a gas mixture comprising two or more of the foregoing drying fluid species.

24. The process of claim 19, wherein said drying fluid is introduced to the contacting at temperature below at least one of 120° C., 115° C., 110° C., 100° C., 95° C., 90° C., 85° C., 80° C., 75° C., 70° C., 65° C., 60° C., 55° C., 50° C., 45° C., 40° C., 35° C., 30° C., 25° C., and 20° C., and above freezing temperature of liquid to be volatilized to form said spray-dried material.

25. The process of claim 19, wherein said drying fluid is introduced to the contacting at temperature below 100° C., and above freezing temperature of liquid to be volatilized to form said spray-dried material.

26. The process of claim 19, wherein average particle size of spray-dryable material droplets in the atomized spray-dryable material in said contacting is in a range of from 50 to 300 μm.

27. The process of claim 19, wherein said drying fluid is introduced to said contacting at relative humidity below 35%.

28. The process of claim 19, wherein said spray-dryable material has a viscosity in a range of 500 to 16,000 mPa-s and a solvent content that does not exceed 50% by weight, based on total weight of the spray-dryable material.

29. The process of claim 19, wherein an electrostatic charge is applied to the atomized spray-dryable material or to spray-dryable material from which the atomized spray-dryable material is generated.

30. The process of claim 29, wherein the electrostatic charge is applied at a voltage in a range of from 0.5 to 75 kV.

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edspap.20190232305