Chemie Ingenieur TechnikVolume 92, Issue 9 p. 1332-1332 Poster Influence of structure on freeze-drying kinetics of instant coffee P. Levin, Corresponding Author P. Levin patrick.levin@tuhh.de Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanyCorrespondence: P. Levin (patrick.levin@tuhh.de), Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanySearch for more papers by this authorV. Meunier, V. Meunier Nestlé S. A, Nestlé Research Center Vers-Chez-Les-Blanc, Route de Jorat 57, 1000 Lausanne, SwitzerlandSearch for more papers by this authorS. Palzer, S. Palzer Nestlé S. A, Executive board, Avenue Nestlé 55, 1800 Vevey, SwitzerlandSearch for more papers by this authorS. Heinrich, S. Heinrich Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanySearch for more papers by this author P. Levin, Corresponding Author P. Levin patrick.levin@tuhh.de Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanyCorrespondence: P. Levin (patrick.levin@tuhh.de), Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanySearch for more papers by this authorV. Meunier, V. Meunier Nestlé S. A, Nestlé Research Center Vers-Chez-Les-Blanc, Route de Jorat 57, 1000 Lausanne, SwitzerlandSearch for more papers by this authorS. Palzer, S. Palzer Nestlé S. A, Executive board, Avenue Nestlé 55, 1800 Vevey, SwitzerlandSearch for more papers by this authorS. Heinrich, S. Heinrich Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21073 Hamburg, GermanySearch for more papers by this author First published: 28 August 2020 https://doi.org/10.1002/cite.202055182AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume92, Issue9Special Issue: 10. ProcessNet-Jahrestagung und 34. DECHEMA-Jahrestagung der Biotechnologen 2020: Processes for FutureSeptember 2020Pages 1332-1332 RelatedInformation

The wetting kinetics of powder-liquid systems represent an important factor with regards to many practical applications, such as coating, granulation, agglomeration or powder reconstitution. Wetting as the first step during food powder reconstitution strongly depends on the interactions of the wetting liquid and the particle surface, expressed by the contact angle. Due to the heterogeneous composition of food materials including hydrophilic and hydrophobic surfaces, also the wetting process heterogeneous in nature. Furthermore, the solubility of food ingredients, such as sugars, increases the complexity of understanding and describing the wettability. We investigated the liquid penetration into heterogeneous, soluble model food powders using a Washburn setup. Soluble sucrose was used as hydrophilic food component and silanized glass beads were prepared as hydrophobic, inert material. Both materials were characterized in terms of contact angle and powder properties. Different mixtures of hydrophilic, soluble sucrose and hydrophobic glass beads were produced and their wetting performance was determined. For predicting the liquid penetration into food powders, the model developed in our previous study (Kammerhofer et al., 2018a [1]) about the penetration of aqueous solutions into food powders was extended. It now considers solute concentration-dependent liquid properties and the heterogeneity of solid surfaces. The model is based on the solution of a coupled system of two differential equations representing capillary rise into a pore network and the mass transfer equation. Two main factors were identified as having a major influence on the wetting kinetics: the viscosity and the contact angle. Increasing either of these factors reduces the penetration performance, but each of them is dominant in a different concentration range. Our adapted model predicts penetration rates which are close to the experimental data. Thus, we can conclude that it is suitable for predicting the capillary penetration into heterogeneous, soluble food powders. (C) 2019 Elsevier B.V. All rights reserved.

The dynamic wetting behavior as first step in reconstitution of heterogeneous model food powders was investigated in the present work. Therefore, we studied the capillary rise of water into single pores and pore systems containing hydrophilic and hydrophobic walls. A two-wall setup was developed to realize the capillary rise in a single gap containing walls with two different contact angles but a constant pore size. The equilibrium penetration height was measured and compared to calculated heights using advancing contact angles inserted in a model equation. Wetting experiments in a Washburn setup were performed with respect to the investigation of water penetration into a heterogeneous pore network which leads to a variable pore size during the rise. In order to determine the effect of contact angle, three different glass materials at varied levels of hydrophobicity were prepared. Furthermore, a focus was put on understanding the impact of the pore network on the wetting kinetics by mixing two size fractions of glass beads. The equilibrium heights determined in heterogeneous single gaps fit well with the calculated heights by inserting advancing contact angles into the model equation. The results of the powder systems show a significant impact on the wetting with an increasing hydrophobic fraction, while an increased hydrophobic contact angle further increased the wetting time only at higher quantities of the hydrophobic component in the sample. Furthermore, our findings emphasize the complexity of wetting into a system with heterogeneity in pore size and contact angle.

Wetting as the first step during food powder reconstitution strongly depends on the interactions of wetting liquid and particle surface, expressed by the contact angle. Due to the heterogeneous composition of food materials including hydrophilic and hydrophobic surfaces, also the wetting process is of heterogeneous nature. Furthermore, the solubility of food ingredients, such as sugars, increases the complexity of understanding and describing the wettability. In this study, we compared experimental water penetration into inert model powders containing hydrophilic and hydrophobic surfaces with theoretical penetration rates which were calculated by modifying a Washburn-based approach for the application to heterogeneous systems. A fair agreement was found when adjusting the porosity of the powder bed. In a second step, the inert powder was replaced by sucrose to introduce the effect of solubility. Since in presence of sucrose the model for inert systems can no longer describe experimentally observed penetration rates, we developed a model for water penetration into food powders considering solute concentration dependent liquid properties. The model is based on the solution of a coupled system of two differential equations representing capillary rise into a pore network and the mass transfer equation. Viscosity was found to have a major influence on the wetting kinetics. Our model predicts penetration rates during the first few seconds which are close to the experimental data. This allows us to conclude that it is suitable for predicting the first seconds of capillary penetration into a particulate system consisting of soluble sucrose.

Pressure agglomeration of powders is widely applied in various industries and an increasing interest lies in the identification and description of contact mechanisms between particles, which are responsible for the compaction product properties. In this paper, the design and development of a novel micromanipulation particle tester (MPT) is presented. This device makes it possible to measure the deformation kinetics and resulting adhesion of two individual particles in contact under load, which are strongly influenced by the applied process conditions. The MPT set-up is, therefore, designed to offer a unique control over the process conditions most relevant to the compaction of powders: external stress, dwell or holding time at constant deformation, compression velocity as well as relative humidity and temperature determining the physical state and mechanical characteristics of hygrosensitive amorphous particles. The latter are often part of powder formulations, e.g. in the food industry, and have been used for force and contact-zone development studies with the MPT. The experimental results on the microscale level will deliver valuable quantitative information for an improved tailoring of pressure agglomeration process conditions of bulk solids.

Coupled DEM–CFD simulations have been performed to study the fluid and particle dynamics in a fluidized bed spray granulator on the scale of individual particles. The aim of this study is to develop a model of a fluidized bed granulator by combining the gas and particle dynamics with a simple model of particle wetting. Based on material tests, the collision behavior of γ-Al2O3 particles was characterized and incorporated into the contact model. For two different granulator configurations, a bubbling fluidized bed with top-spray injection and a Wurster-coater, wetting of the particle surface is estimated based on the residence time distribution inside a biconical spray zone. The effect of the geometry of the apparatus on the homogeneity of wetting is analyzed in order to understand the performance and specificity of different granulator configurations. Compared to the top-spray granulator, the Wurster-coater has a narrow residence time distribution of the particles in the spray zone, which corresponds to more homogeneous particle wetting. For the Wurster-coater, the effect of process parameters like air flow rate and geometry details like the position of the Wurster tube is studied using the model. A stable circulating fluidization regime is established by keeping the jet velocity above 100m/s and the gap distance between bottom plate and Wurster tube below 15 times the particle diameterBased on a description of the physical material properties, an effective modeling tool for design and scale-up of a fluidized bed spray granulator is obtained. Modeling the interactions of the individual particles, a step forward is taken towards a description of the micro-processes in granulation, which also considers the material properties.

Agglomeration technologies are commonly used by the food industry to optimize several properties such as density and flowability and also to shorten the reconstitution time of commercial powders. The latter advantage is mostly linked to the creation of inter-particle pores available for capillary rise. Capillary rise is related to the wetting properties of the solid material evaluated through the contact angle θ. The difficulties in assessing contact angles of food material are discussed in this article. However by choosing appropriate solid/liquid combinations the penetration of droplets into agglomerates was investigated as a function of viscosity and surface tension of the liquid. The wetting rate was found to be in good agreement with the theoretical Washburn equation. Another important factor affecting the reconstitution process of agglomerate is related to the amount of energy that is required to breakdown the agglomerates to individual particles or aggregates. The energy requirements (provided as heat, mixing, etc.) are assumed to be largely influenced by the physical state of the solid bridges. Dissolution of freeze-dried amorphous skimmed milk powder was shown to be much faster than dissolution of a recrystallized sample containing crystalline lactose. In view of the observations made in this article, it seems that implementation of adequate experiments allows investigating individually each step of the reconstitution process. Therefore, it will be desired to describe each step through a set of physical equations and combining these equations into a more comprehensive model. Such model could be used to optimize commercial powders leading to an increased consumer acceptance.

Coupled DEM-CFD simulations were performed to study the fluid and particle dynamics of a fluidized bed granulator on the micro-scale. In a first study, wetting of the particles is estimated based on the residence time distribution inside a conical spray zone. The effect of the geometry of the apparatus on the homogeneity of wetting is analyzed in order to understand the performance and specificity of different granulator configurations. For a small simulation system, heat and mass transfer laws were resolved to calculate the moisture content of the individual particles An effective modelling tool for design of a fluidized bed spray granulator is obtained.

Spray drying consists in atomizing a solution into liquid drops in a hot air flow to get dry solid particles after solvent evaporation. The convective drying at the drop surface leads to a very fast evolution of temperature and water content due to initial high differences of temperature and water vapour pressure between the drop surface and the drying air. During drying, the drop surface viscosity is increasing due to potentially amorphous polymers reaching a rubbery state. The drop surface is becoming sticky with consequences on wall deposit. This sticky behaviour which appears in the range of 10 to 30 degrees C above the glass transition temperature Tg, may be utilized in a positive way for agglomeration of drying particles with dry powders, either recycled fines or new dry powder, to improve instant properties.The evolution of water content of drops along drying, is deduced from measurements of air temperature and relative humidity, at different places in the dryer and used to predict the drying and sticky behaviour of two maltodextrin solutions (DE12 and DE21) with different Tg. The studied parameters in a co-current spray dryer were the inlet air temperature (144, 174, 200 degrees C) and flow rate (80 and 110 kg h(-1)), the liquid flow rate (1.8, 3.6 and 5.4 kg h(-1)) and the rotation speed of the wheel atomizer. The results on particle water content combined with the evolution of Tg showed that particles are sticky close to the atomiser for the two maltodextrins, and also along the chamber for maltodextrin DE21 due to its lower Tg. The introduction of dry particles at different places in the chamber allowed validating the method to control agglomeration. (C) 2010 Elsevier B.V. All rights reserved.

Chemie Ingenieur TechnikVolume 81, Issue 8 p. 1177-1177 PosterFree Access Kollisionsverhalten dominant-plastischer Granulatpartikel L. Fries Dipl.-Ing., L. Fries Dipl.-Ing. lennart.fries@tuhh.de Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Antonyuk Dr.-Ing., S. Antonyuk Dr.-Ing. Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Heinrich Prof. Dr.-Ing., S. Heinrich Prof. Dr.-Ing. Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Palzer Dr.-Ing., S. Palzer Dr.-Ing. Nestlé Research Centre Lausanne, Vers-Chez-Les-Blanc, SwitzerlandSearch for more papers by this author L. Fries Dipl.-Ing., L. Fries Dipl.-Ing. lennart.fries@tuhh.de Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Antonyuk Dr.-Ing., S. Antonyuk Dr.-Ing. Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Heinrich Prof. Dr.-Ing., S. Heinrich Prof. Dr.-Ing. Institut für Feststoffverfahrenstechnik und Partikeltechnologie, Technische Universität Hamburg-Harburg, Denickestraße 15, D-21073 Hamburg, GermanySearch for more papers by this authorS. Palzer Dr.-Ing., S. Palzer Dr.-Ing. Nestlé Research Centre Lausanne, Vers-Chez-Les-Blanc, SwitzerlandSearch for more papers by this author First published: 19 August 2009 https://doi.org/10.1002/cite.200950476AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume81, Issue8Special Issue: ProcessNet-Jahrestagung und 27. Jahrestagung der BiotechnologenAugust, 2009Pages 1177-1177 RelatedInformation

The spray drying process consists of a fast convective drying of liquid droplets by hot air. Initially, the water activity (aw) of a drop is close to 1. During drying, the drop surface aw decreases while viscosity increases until reaching a sticky rubbery state before further drying. This can be observed for products such as carbohydrates, leading to particles sticking on walls (product losses) or to adhesion between particles leading to agglomeration. In this study, particle stickiness was investigated in a cocurrent pilot spray dryer by measuring drying air properties (temperature and relative humidity) at different positions. This allowed describing the evolution of temperature and mean water content of the drying drops. Two model products (maltodextrin DE12 and DE21) were spray dried varying process parameters liquid flow rate (1.8, 3.6, and 5.4 kg/h), air temperature (144°, 174°, and 200°C), airflow rate (80–110 kg/h), and rotary atomizer speed (22,500–30,000 rpm). The two products exhibit different drying behaviors in relation to their affinity towards water (sorption isotherms) and glass transition temperature evolution with aw (stickiness). Depending on drying conditions and product, the drop stickiness was observed very rapidly, close to the atomizer, or later, along the chamber. This approach can be used to identify conditions and positions corresponding to sticky particles.

Chemie Ingenieur TechnikVolume 80, Issue 9 p. 1410-1410 ÜbersichtsvortragFree Access Materialwissenschaftliche Analyse pharmazeutischer, chemischer und lebensmitteltechnologischer Pulver – Vergleichbarkeit verschiedener Pulversysteme und Vorhersage von deren Lager- und Agglomerationsverhalten S. Palzer Dr.-Ing. habil., S. Palzer Dr.-Ing. habil. stefan.palzer@rdls.nestle.com Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26Search for more papers by this author S. Palzer Dr.-Ing. habil., S. Palzer Dr.-Ing. habil. stefan.palzer@rdls.nestle.com Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26Search for more papers by this author First published: 12 September 2008 https://doi.org/10.1002/cite.200750698Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume80, Issue9Special Issue: ProcessNet Jahrestagung 2008September, 2008Pages 1410-1410 RelatedInformation

Chemie Ingenieur TechnikVolume 80, Issue 9 p. 1432-1432 PosterFree Access Unerwünschte Agglomerationseffekte bei der kontinuierlichen Wirbelschichttrocknung von Agglomeraten, welche amorphe Substanzen enthalten – Modellierung des Trocknungsverlaufes und Analyse der Haftmechanismen S. Palzer Dr.-Ing. habil, S. Palzer Dr.-Ing. habil stefan.palzer@rdls.nestle.com Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26Search for more papers by this authorM. Hartmann Dr.-Ing., M. Hartmann Dr.-Ing. Nestlé Product Technology Centre, Lange Straße 21, D-78224 SingenSearch for more papers by this author S. Palzer Dr.-Ing. habil, S. Palzer Dr.-Ing. habil stefan.palzer@rdls.nestle.com Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26Search for more papers by this authorM. Hartmann Dr.-Ing., M. Hartmann Dr.-Ing. Nestlé Product Technology Centre, Lange Straße 21, D-78224 SingenSearch for more papers by this author First published: 12 September 2008 https://doi.org/10.1002/cite.200750692AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume80, Issue9Special Issue: ProcessNet Jahrestagung 2008September, 2008Pages 1432-1432 RelatedInformation

Chemie Ingenieur TechnikVolume 79, Issue 9 p. 1387-1388 TandemvortragFree Access Caking von Lebensmittelpulvern und anderen organischen Produkten – Materialwissenschaftliche Aspekte, Berechnungsgrundlagen und Anwendungen S. Palzer Dr.-Ing., S. Palzer Dr.-Ing. stefan.palzer@rdsi.nestle.com Nestlé Product Technology Centre Singen, Lange Straße 21, D-78224 SingenSearch for more papers by this authorK. Sommer Prof. Dr.-Ing., K. Sommer Prof. Dr.-Ing. Lehrstuhl für Maschinen- und Apparatekunde, TU München (Weihenstephan), Am Forum 2, D-85350 FreisingSearch for more papers by this author S. Palzer Dr.-Ing., S. Palzer Dr.-Ing. stefan.palzer@rdsi.nestle.com Nestlé Product Technology Centre Singen, Lange Straße 21, D-78224 SingenSearch for more papers by this authorK. Sommer Prof. Dr.-Ing., K. Sommer Prof. Dr.-Ing. Lehrstuhl für Maschinen- und Apparatekunde, TU München (Weihenstephan), Am Forum 2, D-85350 FreisingSearch for more papers by this author First published: 18 September 2007 https://doi.org/10.1002/cite.200750389AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume79, Issue9Special Issue: ProcessNet Jahrestagung 2007September, 2007Pages 1387-1388 RelatedInformation

In the food manufacturing and pharmaceutical industry several agglomeration technologies are applied: fluidised bed agglomeration, steam jet agglomeration, agglomeration during drying and pressure agglomeration like extrusion, roller compaction or tabletting. In addition, caking or sticking of amorphous substances, which is a kind of undesired agglomeration, is frequently observed.Any desired or undesired agglomeration of amorphous substances is dependent on the mechanical properties of the entire particle or the particle surface. Changes in the mechanical properties of the material are linked to changes in moisture and temperature and can be predicted by applying the glass transition concept. Using this concept it is possible to estimate the viscosity and the Young's modulus for a given amorphous substance while knowing their glass transition temperature in dependence on the water content.Knowing the viscosity and the Young's modulus and applying equations derived from the sintering technology or the theory of viscoelasticity it is possible to define suitable conditions for most of the agglomeration processes mentioned above. (c) 2005 Elsevier Ltd. All rights reserved.

Wetting of porous systems and the corresponding penetration of liquids into single capillaries is one of the most important processes in process engineering. Wetting liquids with a contact angle smaller than 90° are penetrating spontaneously into capillaries. The presented study demonstrates that, under certain conditions, even nonwetting liquids with contact angles larger than 90° can do so. Furthermore, it is shown that the time for such wetting processes can be calculated.