Laboratory analysis of segregation of powders
Delft Solids Solutions now offers the capability to test the tendency of (pharmaceutical) powders towards segregation in its laboratory.
Considerable efforts are often devoted to the mixing of several different species of powders (of various sizes, shapes and densities) in order to have a homogeneous mixture of the intermediate or final product. Nevertheless, a well-mixed system may segregate during handling, e.g. when discharging into a bin or big-bag, transportation in a truck or pipe-line, but this could also occur when loading the powder in e.g. a tablet press for production of pharmaceutical tablets. Surprisingly, this phenomenon is often overlooked or not adequately tackled.
Prediction and quantification of this segregation phenomenon can now be executed in the Delft Solids Solutions laboratory. The fluidization segregation tendency of powders is assessed in accordance with ASTM D 6941 standard. In this segregation test, a fixed volume of a representative powder sample is fluidized and collected in different fractions. Subsequently, typical characteristics (e.g. particle size or density) of the top and bottom fraction are determined in order to quantify the segregation tendency of the sample. This experimental approach improves the understanding of how transportation and handling efforts can lead to the often undesired segregation of powders.
COURSE Powders and granules: physical properties and behavior
Why the course Powders and granules: physical properties and behavior?
The processing of powders and granules, also called bulk solids technology, is of great importance for various branches of industry, such as the chemical, pharmaceutical, coating, food and feed industry. Depending on the sector, the degree of solids involved can vary from 30-80% of the total product flow. In each of these processes the physical properties (such as cohesiveness, particle size distribution, compressibility, density, etc.) of powders and granular material will greatly affect the quality of the product and the flow properties of powders. Especially in the latter case, powders differ greatly from liquids and gases. Powder particles and granules can also experience wear during production, storage and (pneumatic) transport. The forces encountered can be divided into impact forces, compressive forces and abrasive forces. Impact and compressive forces can break powder particles and granules whereas abrasive forces can cause fines and dust, and this is often an undesired phenomenon.
The processing of powders and granules is still mainly an empirical routine, although the theoretical and practical knowledge on this subject is increasing rapidly. Also more and more techniques become available to mimic the behavior in powder processes on a laboratory scale.
This course examines various techniques to characterize and approaches to test bulk powder behavior. The "flow ability" and "flood ability" of bulk powders are essential in powder storage. Bulk crushing strength but also the tensile strength of individual pellets, granules, and tablets are key in physical transport, as well as the wear and tear (attrition, abrasion) that powder particles and granules can experience. As a result of the latter, the tendency to produce dust (dustiness) can be a point of concern as it impacts on product quality and process conditions, but it can also be relevant for health, safety and environment. During conveying also mixing and demixing (segregation) of powder blends should be carefully considered.
This course teaches you how to make the connection between powder properties and physical properties (e.g. particle size with powder flow and compaction) on the one hand and the modeled background of these properties on the other. You will learn how powder flow can be determined and how to change powder properties, so that the performance can be adjusted in applications.
You are a process engineer, mechanical engineer, food technologist or chemist with a bachelor or academic background and you are working in an industry where solids are processed or manufactured (powders, granules, etc.). Also as operator, analyst, or otherwise interested in these topics, one can greatly benefit from this course.
Solids Technology can be divided into four themes: powder flow and storage, production, handling and physical transport. The course is structured according to these themes, and gives practical meaning to it. A strong link will be made between theory and practice. Below is a list of subjects that will be discussed and questions that will be answered:
+ Powder flow and storage: shear stress, wall friction, consolidation of powders, shear testing, hopper design
+ Production: formulation, granulation, coating.
+ Handling: mixing and segregation (also in relation to particle properties); how to manage it and how to measure it.
+ Solids transport such as pneumatic conveying and the strength of particles, also in relation to attrition, formation of dust, etc.
The course will be given on the location of Delft Solids Solutions in Wateringen (near Delft), where a well-equipped laboratory is available.
Among various readings there are short demonstrations. Many of the experimental methodologies and techniques discussed can be seen in operation.
The course will be hosted by the following lecturers
Dr. Ir. G.M.H. Meesters, Formulation expert, DSM Food Specialties and Assistant Professor at Delft University of Technology.
+ Dr.ir. W. Oostra, senior technical manager at Abbott Healthcare products.
+ Dr. Ing. J.C. Groen, Director Science & Technology, Delft Solids Solutions,
has for many years worked at the TU Delft and gained his PhD on development of hierarchically-structured materials.
+ L.A.A. Peffer, General Director, Delft Solids Solutions, served 25 years at TU Delft as lab manager in the field of particle,
texture and surface characterization.
The course consists of two successive days of 8 hours.
After the course you understand the basic concepts of processes and techniques in which powders and granules play a role. You will be able to design or modify a process in such a way that it is optimally adapted to produce products with the desired properties. On the basis of the many examples, you develop a comprehensive understanding of how powder and granulate properties can be decisive for the final application and how to adapt these.
After following these two days you will receive a certificate of participation.
Location and dates
This course is held at the premises of Delft Solids Solutions: Molenweer 2B, 2291 NR Wateringen, The Netherlands.
The course dates are the 15th and 16th of November 2017