Reducing Complexity & Costs with Smart Pre-Mixing

Infant Nutrition manufacturing is a complicated process with recipes incorporating dozens of ingredients, some of which can be very small in volume. The handling, weighing and conveying of these smaller additions are error-sensitive operations and can be very labour intensive.

This article looks at the benefits of pre-mixing to overcome these issues, provide greater efficiency and reduce the risk of errors.

What do we mean by ‘pre-mixing’?
Pre-mixing is primarily done for reasons of Efficiency. Rather than individually weighing out the minor and micro ingredients for each batch run, pre-mixing involves grouping these into larger quantities, blending them, then dosing out the right quantity of this mix to add to each batch run. This saves on the number of weighments to be made.

Pre-mixing is extremely common in several sectors of B2B dry food trading. It can be done “in-house” or provided as a service from an outside company.

How difficult is it to do?

Minor and micro ingredients vary considerably in volume, weight, particle size and bulk density. There may be 10g of a dense mineral to be mixed with 10kg of light lactose. Mixing these diverse ingredients together as a pre-mix is challenging. Conventional horizontal ribbon mixers are limited in what level of homogeneity they can achieve. Quite often it is necessary to use more sophisticated and modern mixing techniques such as plough share, fluidised bed or vertical ribbon mixers.

After mixing comes the even greater challenge: How to empty the mixer without risking segregation? How to transfer the perfect pre-mix in the exact correct quantity? How to create efficient handling in a central pre-mix area if several big production lines are running different recipes?

To date there has been no reassuring answer to all of these questions. Manufacturers cannot take any process risks so they have to continue running at lower efficiency and rely upon man-power to weigh all the ingredients individually, each and every time, for each batch run.

Loading the minors and micros one recipe at a time is not only time consuming for the operators, but stringent traceability requirements demand that every ingredient is scanned before being tipped into the mixer. This means that the mixer is standing idle during this refill time, so the OEE is severely reduced as a result. Add to this downtime the need for cleaning time if many recipes changes are being made too.

The alternative – IBC systems offer the perfect solution. They provide flexibility and are large enough to scale up the minor and micro ingredient quantities into larger batches. It’s also possible to blend within the IBC and empty straight into the process below. Filling and cleaning are done off-line, so the OEE rates are kept high.

It’s not always that simple – But there have been two fundamental flaws with IBC technology which, to date, have prevented a breakthrough:

  • The ability to empty the pre-mix, which often contains some high fat ingredients, without causing segregation
  • Achieving a homogenous mix across all the different recipes, regardless of the proportion of ingredient volumes and particle sizes.

It’s therefore no surprise that the industry in general has been sceptical and has not adopted IBC technology in a wider sense.

The answer to the segregation issue – Whilst Cone Valve IBCs have been available for over 25+ years, they have only been used for the last 10 years within Infant Formula production for intermediate powder storage. However, an increasing number of companies have realised their value as mixing and transfer vessels.

The Cone Valve is proven to resolve discharge and segregation issues. The cone ‘holds back’ the powder in the centre of the IBC and promotes flow from the sides of the IBC, thus creating mass-flow and avoiding any rolling effects which cause segregation. An animation of this mass-flow can be seen on our website – click here to visit the page. With the Matcon Cone Valve IBC and Discharge Station there is a much reduced risk of segregation during transfer.

In addition, accurate dosing can be performed without the need for additional cross-feeders, thereby reducing the cleaning burden.

The answer to achieving homogeneity – Leading suppliers of stationary tumble mixers (double cone or V) have addressed the homogeneity issue by inserting a central intensifier. This vastly improves blending speed and performance, as well as providing the opportunity to include oil or liquid to the dry blend. But doing the same with mobile IBC Blenders is a far greater challenge.

Matcon started the development to integrate Intensifier technology into IBC Blending some 7-8 years ago. Over time it has been improved, both in terms of mixing performance as well as hygiene. Today we are at a stage where we can supply this technology, confident that homogeneity of mix is achievable, even with a liquid addition, and at the same time, meeting the tough hygienic requirements of this industry.

The opportunity – There are two key areas within Infant Nutrition manufacturing where pre-mixing can be considered: prior to spray drying and post spray drying.

In the first case we are considering the production of slurry prior to spray drying. Whilst the spray drying itself is a continuous process, the dry ingredients are typically mixed batch-wise into large slurry tanks. The number of companies applying dry ingredients in this phase is generally decreasing as they move to make additions post drying. But for long campaigns this is still a viable and efficient concept. 1-2 people per shift can typically be better utilised by adopting pre-mixing in this area.

The second area is final blending after spray drying. This area is growing both in volume and complexity. More and more nutritional ingredients or flavourings are being incorporated to add value and competitive edge to the product SKUs. Since the ingredients are contaminants, this makes the use of an IBC Blender even more relevant as there is no risk of cross-contamination between batches because the product is all contained within the IBC and cleaning is done off-line. Users of this technology are able to achieve OEE on the IBC Blender in the region of 70%. In addition, there are further manpower savings as there is no need to clean the mixing room and surrounding area as there can be with fixed mixers.

The automation opportunity – When dispensing minors and micros for one batch at the time, the weights are generally very low, making automation very demanding to accomplish. But by adopting pre-mixing, each ingredient becomes 10–30 times greater by weight, in other words the 1kg ingredient addition is scaled up to be a 10 – 30 kg addition, which is a sack-full or an amount that can be dispensed from an IBC.

This opens up the opportunity to use formulation systems such as that shown below. The exact configuration will vary from case to case, but the overall investment is suddenly within a range that can be justified and further improve the process security and traceability from the plant.
Hero Spain was using a Ribbon mixer for years to provide small pre-mixes, however, this was creating a bottleneck to their production flow. Five years ago they installed a Matcon Cone Valve IBC and Blending system resulting in a doubling of capacity. They now have capacity to spare from the Matcon pre-mix system!

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