How do you plan a scale-up from pilot plant to production for instant food granules, including risk assessment?
The scale-up of instant food granules describes the transfer of a process optimised in the laboratory or at the pilot plant to a large-scale production plant. The aim is to reproduce the product properties achieved, such as rehydration behaviour, bulk density, particle size distribution, solubility and sensory quality, robustly and reproducibly at industrial scale.
The starting point is the data base from the pilot plant
The basis of every scale-up is a fully characterised set of data from the pilot plant. To this end, raw material properties, process parameters, target variables and critical process parameters are recorded and documented systematically.
The relevant raw material specifications include moisture content, particle size distribution, flow behaviour, solubility and functional properties such as protein content, fat content or starch structure. On this basis, the process conditions at the pilot plant are chosen so that they come as close as possible to later production.
Scale-up strategy and similarity criteria
Planning is specific to the type of process and is based on similarity considerations. Geometric, kinematic and energetic similarity are the central guiding variables.
Important scaling variables are, for example, fill level, tool geometry, circumferential speed, energy input, spray rate and air flow. Ideally, scale-up is carried out in stages from the laboratory through the pilot plant to production, so that non-linearities and equipment effects are recognised early.
Physical particularities during scale-up
At a larger scale, mixing and granulation processes frequently do not behave linearly. Changes in heat and mass transfer, in mixing behaviour and in moisture and air flow can lead to hotspots, moisture gradients, dust formation or inadequate granule structure.
With instant food granules in particular, particle morphology, porosity, density and wettability are decisive. Even small changes in energy input or in drying can markedly influence rehydration, solubility and sensory quality.
Risk assessment
Standardised methods such as FMEA, HACCP, Ishikawa analysis and QbD approaches are used for structured risk assessment. Potential failure modes such as insufficient drying, inadequate granulation, increased fines, allergen carry-over or cleaning risks can thereby be identified and prioritised at an early stage.
Trial planning and process analysis
Systematic trial series are carried out to underpin the scale-up. These include defined variations of fill level, rotational speed, circumferential speed, energy input or process duration as well as documentation of the resulting product quality.
The results are evaluated and documented without gaps. On request, additional measurement and evaluation strategies can be integrated in order to define the process limits and the later operating window robustly.
Qualification and transfer into production
Technical assessment is followed by transfer to the target plant. Because trial and production plants are ideally designed with similar process engineering principles and graded sizes, the pilot-plant parameters can often be transferred well to the production scale.
The scaling-relevant assumptions should nevertheless always be verified by validation trials at a larger scale. This matters for the subsequent investment decision, because product quality, economy and technical risks can thus be assessed realistically in advance.
Manufacture and life cycle
The production plant is then manufactured on the basis of the findings obtained at the pilot plant. After commissioning, inspections, preventive maintenance and spare parts availability remain essential building blocks for ensuring process stability across the entire life cycle.
How amixon® plans a trial and scale-up programme in the pilot plant
Defining the objective before the first trial
The starting point is the operator's acceptance criteria, that is the required mixing quality, discharge rate, protection requirements, batch size range and cycle time. amixon® experts translate these targets into a structured trial programme on one of the 35 test units, in the size that matches the available product quantity.
Systematic parameter variation
The scale-up-relevant variables are varied: mixing time, circumferential speed of the tool within the window of approximately 0.8 to 3.5 m/s, fill level as well as, where relevant to the process, the dosing rate and type of liquid addition, for example via a lance or a two-fluid nozzle with or without a cutting rotor. Samples are taken at every trial point and the mixing quality is determined, while discharge rates are verified gravimetrically.
Transfer to production scale
Because pilot-plant and production mixers work with an identical mixing principle and are scaled via the circumferential speed rather than by rotational speed alone, the parameters found are fundamentally easy to transfer. The size grid in 100-litre increments up to 50,000 litres allows the design to match the target batch size exactly, without any unnecessary break in similarity.
Much can be calculated, yet not every question can be answered reliably by calculation alone. For many topics amixon® has empirical values that can be drawn on during the development process. Some questions, however, must be answered experimentally, such as the dynamic pressure that builds up in the tool area when instant food granules are mixed.
It is precisely here that a trial series with batches of different sizes provides particularly robust statements. Trials with 1 litre, 10 litres, 100 litres, 1,000 litres and 3,000 litres allow very precise conclusions for the scale-up. The behaviour in a 10 m³ batch can thus also be predicted with considerably greater certainty.
Documentation as a basis for investment
The trials are carried out, evaluated and documented jointly. The trial report confirms the process parameters under real conditions and names the optimum apparatus. Target mixing quality, discharge rates and cycle times are thereby adopted robustly into the plant specification, and risks are ideally eliminated before the investment rather than discovered afterwards.
For instant food, amixon® systems are proven in practice, for example twin-shaft mixers with automatic wet cleaning when changing between savoury and sweet, the KoneSlid® for fragile spray-dried and agglomerated materials and the RMG for low-dust, rapidly soluble granules.
Manufacture in Paderborn as the quality foundation
amixon® develops and manufactures exclusively at the Paderborn works with a high depth of manufacture and all components from Germany. As a certified welding company with European, Japanese, Korean and American qualifications, amixon® designs every apparatus as a one-off on the basis of the operator's URS, and quality control remains entirely in-house without gaps. This manufacturing autonomy also secures long-term supply, since every component can still be re-manufactured reproducibly decades later.
Service across the entire life cycle
After commissioning, amixon® remains at the operator's side. Regular inspections and preventive maintenance secure availability, on request supplemented by predictive maintenance. Selected wear parts are supplied together with the initial delivery, most spare parts are held at the Paderborn site, many more at the service bases in Japan and the USA, so that a lifetime spare parts service remains possible even where original suppliers cease to exist. Many amixon® machines have been in daily use for more than 30 years; modernisation and retrofitting keep them at the state of the art.