In-house C massecuite reheater: a successful development for Le Gol sugar factory

Abstract

Prior to 2020, due to an aging C massecuite reheater, the Le Gol sugar factory had issues with sugar quality (foreign particles) and back-end factory maintenance (weekly damage to centrifugal screens). Thus, a new reheater was required and was an opportunity to improve C molasses exhaustion. A commercial design was first considered but without a guarantee of efficiency improvement. An in-house reheater was designed and manufactured based on in-house skills that included maintenance and production teams. Several digital simulations enabled the investigation of tube layout, fin and partition designs, massecuite and water flows, and the need for thermal insulation. Raw materials for tubes and fins were chosen depending on massecuite composition, and a specific steel (Duplex stainless steel) seemed to be the most suitable. As the reheater shell was still in good condition, it was reused, and the new heating elements (provided by an external service but based on the in-house design) were implemented. Instrumentation and process control were improved, enabling fine-tuning of the steam consumption and improved C molasses exhaustion. The new reheater has been operating since the 2020 crop season. Results are even better than expected, and C molasses exhaustion has improved. There are no longer breakdowns due to screen damage. Maintenance costs are reduced as, for example, strainers have to be cleaned once a week instead of twice a day. Thanks to a better heat transfer, the target temperature of 57 °C for the outlet massecuite is achieved and maintained faster, and the inlet water only needs to be at 58°C (compared to 62 °C previously and even then, the target temperature wasn't achieved.) This approach promotes teamwork and is gratifying for co-workers. Moreover, all this development was successfully done during the first period of the Covid pandemic, showing Le Gol staff’s great adaptability and personal involvement.