TY - JOUR
T1 - Design of a pilot-scale microwave freeze dryer for in situ neutron imaging
AU - Hilmer, Mathias
AU - Gruber, Sebastian
AU - Kis, Zoltán
AU - Schulz, Michael
AU - Foerst, Petra
N1 - Publisher Copyright:
© 2024 Author(s).
PY - 2024/8/1
Y1 - 2024/8/1
N2 - The gentle yet cost-effective drying of sensitive products in the food and pharmaceutical industries is becoming increasingly important. To maintain sensitive ingredients, color, structure, and viability of micro-organisms, often freeze-drying is the only possible way to preserve the product. As many products come in as bulk material, they are dried on heated shelves resulting in poor heat and mass transport through the bed. Resulting in a very time and cost intensive process. Therefore, efforts are being made to improve the mass and heat transport of the process. The outer mass transport through the bulk can be improved by continuous mixing of the pellets, facilitating the removal of water vapor from the condenser. In addition, the issue of limited heat transport can be addressed by using volumetric energy input from microwaves. This process is called dynamic microwave freeze-drying. As dynamic microwave freeze-drying is a combined drying and mixing process, with particle properties continuously changing during drying, it is necessary to gain a more detailed insight into the process. For this purpose, a drier is designed that is capable of in situ neutron imaging, a method sensitive to a material’s hydrogen content. This paper presents the design of a pilot-scale microwave freeze dryer for in situ neutron imaging and shows the first images taken during the dynamic microwave freeze-drying of bulk particles at the Center for Energy Research, Budapest Neutron Center in Budapest, Hungary.
AB - The gentle yet cost-effective drying of sensitive products in the food and pharmaceutical industries is becoming increasingly important. To maintain sensitive ingredients, color, structure, and viability of micro-organisms, often freeze-drying is the only possible way to preserve the product. As many products come in as bulk material, they are dried on heated shelves resulting in poor heat and mass transport through the bed. Resulting in a very time and cost intensive process. Therefore, efforts are being made to improve the mass and heat transport of the process. The outer mass transport through the bulk can be improved by continuous mixing of the pellets, facilitating the removal of water vapor from the condenser. In addition, the issue of limited heat transport can be addressed by using volumetric energy input from microwaves. This process is called dynamic microwave freeze-drying. As dynamic microwave freeze-drying is a combined drying and mixing process, with particle properties continuously changing during drying, it is necessary to gain a more detailed insight into the process. For this purpose, a drier is designed that is capable of in situ neutron imaging, a method sensitive to a material’s hydrogen content. This paper presents the design of a pilot-scale microwave freeze dryer for in situ neutron imaging and shows the first images taken during the dynamic microwave freeze-drying of bulk particles at the Center for Energy Research, Budapest Neutron Center in Budapest, Hungary.
UR - http://www.scopus.com/inward/record.url?scp=85200828408&partnerID=8YFLogxK
U2 - 10.1063/5.0213685
DO - 10.1063/5.0213685
M3 - Article
C2 - 39109901
AN - SCOPUS:85200828408
SN - 0034-6748
VL - 95
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 8
M1 - 083704
ER -