Particle characterisation a key to process efficiency

Paul Boughton

Understanding particle characteristics is fundamental to process operations. New technologies that simplify this will increase process efficiency, says Sean Ottewell, and help to cut costs.

The installation of a multi-detection Viscotek TDAmax gel permeation chromatography (GPC) system from Malvern Instruments is enabling Dow Corning Europe in Belgium to meet customer demand for increasingly comprehensive polymer structure data.

In addition, Dow Corning experts are saving resources by applying rapid, cost-effective GPC methods to pre-select the most promising new polymer candidates, significantly reducing the number of nuclear magnetic resonance (NMR) investigations required wherever possible (Fig. 1).

"We're seeing increased demand from our customers for structural data and for more in-depth characterisation of polymer and co-polymer samples," said Stephane Cornelis, global business service - analytical sciences, Dow Corning Europe.

"Structural information is beneficial because we can quickly compare samples and characterise any changes in behaviour following polymer grafting, for example. The Viscotek GPC with triple detection uses an easy-to-read Mark-Houwink-Sakurada plot to visualise changes in molecular weight and intrinsic viscosity against a reference sample. This is a real time saver," he added.

"Additionally," he continued. "By using multiple-detection GPC to characterise new polymer candidates we have been able to pre-select only the most interesting for further study. This has allowed us to reduce the number of more expensive and time consuming NMR investigations."[Page Break]

Potential of silicones

Established in 1943 specifically to explore and develop the potential of silicones, Dow Corning is a global leader in silicones and silicon-based technology and innovation. The company now offers more than 7000 products and services.

Viscotek instruments apply a combination of refractive index (RI), viscosity, light scattering and ultra-violet (UV) detection following GPC sample separation. With the detectors connected in series, the entire measurement sequence uses a single, un-split volume of sample to deliver high accuracy results.

Grinding circuits

Meanwhile, at its production site in Heming, France, Holcim is using an Insitec on-line particle size analyser from Malvern Instruments to optimise the grinding circuits in its mill. By continuously monitoring two parallel production lines, the Insitec supplies the data needed to optimise throughput and at the same time produce product of the highest quality.

"For us, the Insitec is an essential tool for optimising the performance of the finishing mills and it is of great value to the production teams," said Michel Berger, chemist - instrumentation and environment specialist. "It provides continuous particle size data for the material exiting the mills, so that the operators can react quickly and confidently when making control decisions.

"We now control the plant extremely closely and transition between different product grades very efficiently. As a result we have increased throughput and enhanced product quality.'

At the Heming site two identical grinding circuits operate in parallel. The Insitec samples each one alternately, providing particle size distribution data for each line every ten minutes. Before its installation the site relied on off-line analysis in the laboratory. This demanded greater manual input and meant a delay of around 15 minutes between sampling and receiving results.

The timely information provided by the Insitec supports more responsive control which leads to greater operational efficiency.

Particle size analysis of raw materials is often a necessary but routine task where speed and efficiency are critical to decision-making and the smooth operation of a manufacturing process.

Malvern says its new Mastersizer 3000 supports improved productivity through fast, fully automated measurement and cleaning, combined with instrument and data analysis software that streamlines every aspect of the instrument's use.

In-built intelligence supports each measurement, from the outset through to a successful conclusion. The result is robust and reliable data produced with ease and efficiency and minimal operator input.[Page Break]

Commodity handling

The Mastersizer 3000 harnesses robust and proven laser diffraction technology to deliver a particle sizing instrument that is highly suited for raw material and commodity handling requirements, and can be used by operators with different backgrounds and experience. It measures particles across a wide size range from 10 nm to 3500 µm, efficiently analysing both wet and dry samples.

Measurement is rapid and robust, even for polydisperse materials. Switching between sample types is simple with auto locking dispersion cells and automatic system initialisation. All of which ensures the reliable results necessary for production control.

System software plays a crucial role in lightening the analytical workload. Real-time feedback during method development accelerates the optimisation of every measurement, with a developed method then locked down as a standard operating procedure (SOP) to secure validatable performance. An in-built Data Quality Expert alerts and guides the user in the event of a problem during analysis, while an edit-in-place report designer allows the tailoring of results so that data is presented in the most appropriate form for every application.

Joining forces

FEI, a leading instrumentation company providing imaging and analysis systems for research and industry, has acquired ASPEX Corporation. ASPEX provides rugged scanning electron microscopes (SEMs) and related services for environmentally demanding industrial and other applications.

"The ASPEX EXtreme SEM is an integral part of our QEMSCAN WellSite solution for on-site oil and gas solutions," noted Don Kania, president and ceo of FEI. "With this acquisition, FEI now owns the essential hardware and software that has been part of our rapid growth and expanding potential in the natural resources business. In addition, ASPEX has a solid track record of applications in a range of industrial markets," he added.[Page Break]

Quality control

Another key product in the ASPEX portfolio is OmegaMax. This works in concert with the company's EXpress and EXtreme platforms, which detect, identify, quantify and characterise the features of entire samples automatically and unattended for the purpose of quality control.

Adding OmegaMax to these powerful microanalysis systems enables them to analyse samples twice as fast with substantially better energy resolution, all at an affordable price.

"OmegaMax enhances our ability to provide highly optimised SEM/EDS systems that solve important real-world materials characterisation problems," said Frederick Schamber, ASPEX chief technical officer.

"The key to the OmegaMax breakthrough was to take an integrated system approach to the incorporation of an x-ray sensor in the SEM architecture," said Schamber.

"By abandoning prior conventions about how an EDS detector is configured, we have been able to innovate some new approaches that lead to much more efficient use of the sensor. Consequently, we can now offer a much higher level of performance," he added.

Laboratory instrumentation manufacturer Fluid Imaging Technologies has introduced VisualSpreadsheet V3.0 particle analysis software. A companion to the company's FlowCAM particle imaging and analysis system that automatically detects, images and identifies particles, VisualSpreadsheet V3.0 features new custom graphing functionality that allows users to create custom scattergrams and histograms by choosing the variables on the x and y axes from a menu of the system's 32 different measurement parameters without rerunning the sample.

Permitting the size, length, width, perimeter, roughness, intensity, fluorescence and the other parameters to be quickly switched both during and after processing, VisualSpreadsheet V3.0 provides access to more than 1000 different combinations for segmenting and evaluating the data from new perspectives that were previously unavailable on any type of analysis instrumentation.

Ideal for laboratory managers, water quality engineers, process engineers, quality control managers, research scientists and others, VisualSpreadsheet V3.0 comes installed with the FlowCAM instrumentation and is backwards compatible for seamless retrofit on models currently in the field.

Micromeritics' new innovative MicroActive data analysis software allows users to interactively evaluate isotherm data from Micromeritics' ASAP, TriStar, and Gemini gas adsorption instruments.

Interaction with adsorption data is direct. Users can easily include or exclude data, fitting the desired range of experimentally acquired data points.

Interactive data manipulation minimises the use of dialogue boxes to specify calculation parameters allowing accurate and efficient determination of surface area and porosity of their materials. By simply moving calculation bars with the cursor, the user is immediately updated with the new textural properties.

One-click access to important parameters allows the user to focus on the result rather than the parameters. It is not necessary to generate reports to view results - now see it graphically and interactively on the screen.

Hosokawa's powder tester PT-X employs the methods developed by Ralph L Carr (Carr Indices) to determine the flowability and floodability of dry powders. The model PT-X is the latest design of the Hosokawa Micron powder characteristics tester which utilises state of the art features to identify the specific characteristics of powdered samples for a wide range of application fields.

The company has also introduced a free App Box with four new functions (with additional calculations on the way). The 'Hosokawa Calculator' is designed for individuals working with dry powders, providing quick and easy calculations.

With this application, users are able to convert mesh screen size to microns, millimetres, inches and vice versa. Air flow conversions allow users to quickly determine the actual air density associated with operational conditions and calculating conveying velocities in ducting.

Containment strategies for dry powder processing equipment can be quickly determined based on given set of product characteristics and operational conditions. Hosokawa says that this could also be a great tool for the quick evaluation of associated process risks.