Increased profitability via plant size optimisation

In order to take these factors into account during the planning stage, essential pre-requisites, such as correct scale-up from laboratory to pilot scale, and finally production scale, as well as having a process technology which is ideally suited to the product being handled, all must be considered. High quality equipment is assumed to command relatively high acquisition costs. Having made a major investment, the ongoing efficiency of the system needs to be guaranteed. Today, technology must be able to fulfill several requirements at once. In times of short life cycles and fast-changing market needs, it is of great importance that different products are produced efficiently and that the equipment can be used in a variety of ways. As a result, many questions arise during the planning phase: How many new products will be introduced each year? How often will switching from one product to another occur? Several times per day, or just once a week? Will it be necessary to clean the equipment between batches? The use of large production vessels does not automatically guarantee a higher product turnout, as the process could be extended disproportionately, particularly so in cases where heating/cooling intervals could have a significant influence. This article will pay particular attention to the issue of scaling up.

Important parameters

The highest expectations with respect to productivity, as well as product quality, must be fulfilled in the cosmetics industry of today, as emulsions, dispersions and gels are produced in large quantities. It is essential to be able to work with large viscosity ranges, efficient solids incorporation has to be guaranteed, and homogeneous blending is to be achieved in the shortest possible time. Therefore, production equipment has to provide multiple processing steps – such as solids dispersion, emulsification, blending, heating and cooling – all as efficiently as possible, while at the same time providing optimum product quality. The hot/hot procedure is used for the production of a variety of cosmetic products. Water, as well as oil, is usually heated to high temperatures for products such as creams, lotions, masks and gels, requiring emulsification processes. This heating phase is often necessary during the oil phase, as ingredients, such as waxes, must first be melted. Both phases are then combined with each other, once the appropriate temperature is reached, an emulsion is formed by using a suitable dispersion procedure. In many cases it becomes necessary to homogenise the product for an extended period of time at high temperatures in order to achieve the relevant product quality and particle size distribution in the dispersed phase. W/O (water in oil) and/or O/W (oil in water) emulsions can be produced using hot/hot procedures. Once the emulsification has taken place, the product is cooled down during a controlled cooling phase to a filling temperature of approximately 25°C. It may be necessary to cool the product while the homogeniser is still running in order to achieve the required product quality. Due to the high temperatures, the amount of heat to be dissipated is very high, which results in a longer cooling phase. Furthermore, cooling times have significant influence on the length of the production cycle. The product volume, as well as specific heat capacity, are important and critical parameters. Energy savings can only be achieved when the product temperature is kept as low as possible when the phases are being joined. This can be achieved if one of the two process phases has a “cooler” temperature during dispersion and joining of the product. In most cases this has to be the aqueous phase, as melted waxes are often a part of the oil phase. Therefore, the cold water phase which was previously prepared in the pre-phase vessel, is introduced and homogenised into the heated oil phase in the main vessel. When the change from a hot/hot process to a hot/cold process is to take place, it is essential that the phase, which has to be dispersed, is introdused via the homogeniser into the vessel to achieve instant homogenisation. In earlier, traditional processes the additional phase was often mixed in from the top of the open vessel and then homogenised. Now it is possible to simply join the phases by using the dispersing zones of the homogeniser. This, of course, would require a system that makes an introduction into the dispersion zones possible. In addition, the homogeniser must be able to circulate the generated product and/or provide a continuous product exchange. Total homogeneity of the product must be achieved when in the mixing vessel. If the system is not of optimum design, then poor mixing will occur, which will require additional processing time, these additional mixing and homogenising processes will increase the total production time. The advantage of the Ekato Systems homogenisation process becomes quite obvious when compared to the hot/hot process, as the product temperature can be significantly lowered directly after the joining phase with hot and cold phases. Less energy (heat) must be dissipated based on the lower blending temperature; in other words a significantly shorter cooling time, as well as shorter total process time, is achieved.