Periodic Reporting for period 1 - SpeeDrying (An Innovative and Sustainable Spray Drying Technology)
Berichtszeitraum: 2017-01-01 bis 2018-12-31
Spray drying (SD) is the main process used for producing powders from a liquid feed. It has unique advantages, such as the ability to produce powders with a specific particle size and moisture content, handling heat sensitive products, and possibility of high volume application. In recent years, the research focus was on understanding and modelling the SD process to facilitate the choice of operating conditions and to optimize energy usage.
However, SD remains a complex energy intensive process. There is a need to develop and industrially implement flexible and sustainable processes for the production of highly functional powders from a complex multiphase liquid feed.
SD is a convective drying method, which has low thermal efficiency. A liquid feed is atomized at the top of a drying chamber into a flow of hot air. Due to the low energy efficiency, industrial SD chambers have a large volume, making difficult to control morphology and quality of the final product. Large volumes also lead to longer warm-up periods, as a larger hot air flow needs to be ensured. Unlike the convective heating, electromagnetic drying is rapid and energy efficient, it promotes expulsion of inner water to the surface, and it allows selective heating of the materials.
This project aimed for: (i) exploring electromagnetic drying to suggest the design of a sustainable SD process; (ii) generating products with well-defined structure and functionality, by new drying technology and detailed structure development, to design innovative powders.
The work was performed on a lab and pilot scale, transferring fundamental to applied knowledge. Potential of applying electromagnetic drying on a single particle for designing a more energy efficient process was demonstrated. By selecting the right wavelength the drying speed was improved and a heated medium was avoided. Process-structure-property functions were established.
Finally, this project set science for processing new food/pharma powder structures with innovative functions to meet consumers’ needs, by generating potential for related future products of interest for food and pharmaceutical industries. Moreover, the demonstrated potential of using electromagnetic heating set the base for the development of an innovative and sustainable SD process, which is expected to have significant economic and environmental impact.
However, SD remains a complex energy intensive process. There is a need to develop and industrially implement flexible and sustainable processes for the production of highly functional powders from a complex multiphase liquid feed.
SD is a convective drying method, which has low thermal efficiency. A liquid feed is atomized at the top of a drying chamber into a flow of hot air. Due to the low energy efficiency, industrial SD chambers have a large volume, making difficult to control morphology and quality of the final product. Large volumes also lead to longer warm-up periods, as a larger hot air flow needs to be ensured. Unlike the convective heating, electromagnetic drying is rapid and energy efficient, it promotes expulsion of inner water to the surface, and it allows selective heating of the materials.
This project aimed for: (i) exploring electromagnetic drying to suggest the design of a sustainable SD process; (ii) generating products with well-defined structure and functionality, by new drying technology and detailed structure development, to design innovative powders.
The work was performed on a lab and pilot scale, transferring fundamental to applied knowledge. Potential of applying electromagnetic drying on a single particle for designing a more energy efficient process was demonstrated. By selecting the right wavelength the drying speed was improved and a heated medium was avoided. Process-structure-property functions were established.
Finally, this project set science for processing new food/pharma powder structures with innovative functions to meet consumers’ needs, by generating potential for related future products of interest for food and pharmaceutical industries. Moreover, the demonstrated potential of using electromagnetic heating set the base for the development of an innovative and sustainable SD process, which is expected to have significant economic and environmental impact.
A lab scale single droplet drying (SDD) kinetics device, based on acoustic levitation, was setup. This allowed drying of single droplets using dry air and/or infrared (IR) heating. It was used to investigate the effect of physicochemical properties of the liquid feed on particle formation, and IR wavelength on heating efficiency. To investigate the possibility to use microwave drying during powder production, a lab scale process was designed, allowing production of a powder with innovative functional properties.
Three draft publications and a patent were prepared and they will be submitted starting from March 2019. Two publications focus on: (i) morphology development in single drop drying for whey protein (WPI) solution and its colloidal aggregates; and (ii) IR laser heating of single droplets. The patent is about innovative protein based dried products. The third publication will follow the patent, reporting the innovative properties of the developed product and guidelines for its production.
Projects results were presented at European and international conferences and at industrial seminars. They will continue to be presented in the coming year. In addition, this project set science for processing new structure with innovative functions, which will be followed up by future research projects. Results were also well received by industry partners acquired during the project.
Following the main scientific results are presented.
- Morphology of WPI solutions and its colloidal aggregates
The control of particle morphology during the SD of food powders is one of the key factors affecting powder properties in food applications, in a dry and reconstituted state. Generic research in the field of drying of colloid suspension revealed the key mechanisms in play for systems whose behavior may be modeled with a few parameters describing colloidal interactions, Brownian motion, evaporation rate, as well as hydrodynamic stresses generated during drying. In this study, we validate models used to predict and control morphology of nanoparticles, for WPI powders, which are of main interest for pharma/food industries. WPI was used in its native and aggregated state. Single particle of WPI solutions were dried using the SDD device. Results showed that the morphology development and final morphology of the particles are significantly affected by colloidal size. Such phenomenon was successfully explained by calculating relevant parameters for describing mechanical properties of particle shell. In conclusion, we showed that it is possible to achieve diverse final morphologies of particles using same drying conditions and starting from the same type of colloids (WPI) but with different degree of aggregation. In addition, it is possible to predict final morphology of particle by estimating mechanical properties of the particle shell. This fundamental knowledge establishes the base for controlling particle formation and functionality of food/pharma dried products.
- Electromagnetic drying of single particles
The goal of this study was to improve thermal efficiency of the SD process by combining electromagnetic and convective heating. To understand potential of this novel methodology, electromagnetically assisted drying of single droplets was performed. Self-engineered electromagnetically assisted heating systems were tested for trials food feeds droplets, water and oil based. It allowed heating and drying single droplets at different power and wavelengths. Results showed that heating/drying of oil/water based droplet was instantaneous and fast cooling was possible since the surrounding air was not heated. Efficient heating/drying was achieved using larger wavelengths and higher power, thanks to the greater penetration depth.
In conclusion, single droplets were successfully dried using a IR heating system. By selecting the right wavelength drying efficiency was improved. Since no air flow was needed to heat the droplet, intermittent heating was performed as well as rapid cooling. Combination of electromagnetic energy and SD is a novel technology. This study set the base for the development of efficient drying techniques in the food/pharma/chemical industry.
Three draft publications and a patent were prepared and they will be submitted starting from March 2019. Two publications focus on: (i) morphology development in single drop drying for whey protein (WPI) solution and its colloidal aggregates; and (ii) IR laser heating of single droplets. The patent is about innovative protein based dried products. The third publication will follow the patent, reporting the innovative properties of the developed product and guidelines for its production.
Projects results were presented at European and international conferences and at industrial seminars. They will continue to be presented in the coming year. In addition, this project set science for processing new structure with innovative functions, which will be followed up by future research projects. Results were also well received by industry partners acquired during the project.
Following the main scientific results are presented.
- Morphology of WPI solutions and its colloidal aggregates
The control of particle morphology during the SD of food powders is one of the key factors affecting powder properties in food applications, in a dry and reconstituted state. Generic research in the field of drying of colloid suspension revealed the key mechanisms in play for systems whose behavior may be modeled with a few parameters describing colloidal interactions, Brownian motion, evaporation rate, as well as hydrodynamic stresses generated during drying. In this study, we validate models used to predict and control morphology of nanoparticles, for WPI powders, which are of main interest for pharma/food industries. WPI was used in its native and aggregated state. Single particle of WPI solutions were dried using the SDD device. Results showed that the morphology development and final morphology of the particles are significantly affected by colloidal size. Such phenomenon was successfully explained by calculating relevant parameters for describing mechanical properties of particle shell. In conclusion, we showed that it is possible to achieve diverse final morphologies of particles using same drying conditions and starting from the same type of colloids (WPI) but with different degree of aggregation. In addition, it is possible to predict final morphology of particle by estimating mechanical properties of the particle shell. This fundamental knowledge establishes the base for controlling particle formation and functionality of food/pharma dried products.
- Electromagnetic drying of single particles
The goal of this study was to improve thermal efficiency of the SD process by combining electromagnetic and convective heating. To understand potential of this novel methodology, electromagnetically assisted drying of single droplets was performed. Self-engineered electromagnetically assisted heating systems were tested for trials food feeds droplets, water and oil based. It allowed heating and drying single droplets at different power and wavelengths. Results showed that heating/drying of oil/water based droplet was instantaneous and fast cooling was possible since the surrounding air was not heated. Efficient heating/drying was achieved using larger wavelengths and higher power, thanks to the greater penetration depth.
In conclusion, single droplets were successfully dried using a IR heating system. By selecting the right wavelength drying efficiency was improved. Since no air flow was needed to heat the droplet, intermittent heating was performed as well as rapid cooling. Combination of electromagnetic energy and SD is a novel technology. This study set the base for the development of efficient drying techniques in the food/pharma/chemical industry.
The “SpeeDrying” project set science for processing new structure with innovative functions. It set points for nucleating ideas that were well received by industry partners acquired during the project. More time is needed to reach industrial applicability. However, the results obtained showed it is possible to improve drying efficiency of drying processes by selecting the right wavelength when designing electromagnetically assisted drying processes. In addition, thanks to the understood relations between process and product structure and functionality, a new protein based structure was developed. This new material is currently in a transition state from research to industrial applicability.