Vertical continuous pans (VKT) from BMA were developed to ensure maximum exhaustion or crystal content for a wide range of massecuite purities in the beet and cane sugar factories and sugar refineries. To date, VKT have been installed in more than 75 factories, meeting very high requirements: process continuity, massecuite with a high crystal content, and a small footprint for outside installation.
Unlike in batch-type crystallisation and evaporation processes, the operator only has monitoring duties during normal operation.
Consistent operating conditions make for long working cycles. VKT from BMA feature a bypass system that optimises the cleaning process. This permits continuous 24/7 operation of the VKT during the campaign.
In contrast to batch-type crystalliser, the VKT permits a consistent level of vapour bleeding from the evaporator station. This results in more even running of the evaporator station and a consistent dry substance content of the thick juice.
The low massecuite level above the calandria keeps the heating steam pressure low when an agitator is used. Moreover, circulation and homogeneity of the massecuite are improved. The heating steam can therefore be taken from a downstream effect of the evaporator station and fully used in the upstream effects.
If the factory output has to be reduced, the crystallisation and evaporation in the VKT is adjusted simply by lowering the heating steam pressure. The combination of an agitator and a double-cone bottom ensure continued good circulation and homogeneity of the product. It is therefore not necessary to add water or steam to the massecuite, making the process more energy-efficient.
Adding a feed solution with a very high dry substance content (e.g. >75 Brix) and/or a superheated solution to the vacuum-sealed vapour chamber results in flash evaporation. This produces incrustations and fine crystals in the VKT. One undesirable effect of the incrustations is that they shorten the operating time of the VKT. The presence of spontaneously formed crystals changes the crystal size distribution curve (e.g. higher CV values) and is often not acceptable for end customers.
To minimise flash evaporation, BMA only ever adds the feed solution to the lower cone (see Fig. 1), as is the case with the batch pan (DVK).
The vertical continuous pan (VKT) has proved to be a positive force in the sugar sector: simple process control and automation, continuous material flows and small temperature differences.
Policy changes regarding energy conservation and the substitution of carbon-based energy sources have brought the VKT into the spotlight. It achieves energy savings thanks to the very small temperature differences between the heating steam and the massecuite.
The difference in pressure between vapour and heating steam is also very small, making the VKT the perfect choice for mechanical vapour recompression (MVR). In this process, vapour from the VKT is compressed to increase pressure and then reused as heating steam.
Please refer to the product brochure for more detailed information. We would also be happy to advise you in a personal consultation.