Full Flexibility with Spouted-Bed – Glatt’s ProCell continuous spouted-bed equipment makes high-quality granulates and pellets

At the end of 2009, one of the world’s largest spouted bed systems for granulation started at the Dresden-based contract manufacturer IPC. A ProCell 250 from Glatt Ingenieurtechnik GmbH enables a so far unreached flexibility for agglomeration and spray granulation processes. Liquid and/or solid raw materials can be processed to granulates and pellets or existing particles can be coated. Batch or continuous operation is possible.

» originally published in the trade magazine ‘PROCESS worldwide’, issue 02/2011, VOGEL Communications Group GmbH & Co. KG

Glatt Ingenieurtechnik GmbH is one of the leading suppliers of systems for continuous manufacturing of granulates and pellets on the basis of fluid bed and spouted bed technologies. Depending on customer request, the scope of supply for granulation systems comprises either the main equipment only or the complete plant including the building.

Also for IPC, Glatt Ingenieurtechnik delivered not only technology and process equipment for the new manufacturing site, but engineered and implemented the entire building complex stretching over 4 floors.

Solid starting material, e.g. for powder agglomeration, are brought directly from the warehouse to level 1 of the plant. There, they are discharged into plant-internal product containers on level 0 using a combined Big Bag and paper bag discharge station. After transport of the containers to level 3 by elevator, the containers are discharged via a docking station into the metering container of the gravimetric metering device.
Liquid starting substances are brought from the warehouse to level 0. There they are filled into a spray tank that can also be heated. From this tank, the liquids are directly sprayed into the ProCell 250 – granulates are formed. The ProCell 250 stretches over 3 levels:

  • level 1: inlet air chambers and process chamber,
  • level 2: expansion chamber with filter housing, and
  • level 3: accessible clean gas chamber.

The granules leave the process chamber in level 1 and fall on the level 0 by gravity. There, they can be cooled in a helical vibration conveyor if required. Then, the granules are pneumatically conveyed to a screen on level 2 where oversized and undersized particles are separated from the product. Oversized particles are milled and pneumatically returned to the ProCell 250 process chamber together with undersized particles (screening-milling cycle). Screened product falls into a product silo in level 1. Out of this silo it falls to a Big Bag filling station in level 0. Filled big bags are transferred to the warehouse.

For a contract manufacturing plant flexibility and ease of cleaning are of great importance. Manufacturing and technical areas are strictly separated, to protect the technical area against contamination with product. Only the manufacturing area needs to be cleaned.
All equipment components are selected with respect to easy cleaning, e.g. star feeders with quick-change star or easily removable pneumatic conveyor pipes. The liquid pumps and the manifold for the spray nozzles are installed on trolleys that can be moved to the washing room. The ProCell 250 is equipped with a WIP system. The spray nozzles can remain in the plant during washing. The internal bag filter is washed by cleaning nozzles. Cleaning nozzles are also installed in the clean gas chamber.

When equipped with a bottom screen and is thus operated as a fluid bed system, the tremendous process flexibility of the ProCell 250 can be further increased. The spray system is designed for spraying aqueous solutions and suspensions and also molten substances. For spraying molten material, the spray system can be heated. Agglomeration and coating processes are possible by simultaneous metering of solid material and spraying of liquids. Process gas temperatures between 15°C and 200°C as well as different process gas quantities also widen the application options of the plant.

In order to process products with a risk of dust explosion, the ProCell 250 is equipped with an explosion suppression system.

IPC – International Process Center – based in Dresden, is a certified manufacturing site for contract manufacturing of finished products for the food, feed and fine chemicals industries. For this, mainly advanced fluid bed processes with focus to granulation and coating are used.

The production with the ProCell 250 as core equipment is now the sixth plant on this site. Already in 2005, the first extension stage of one existing batch-type fluid bed system began. With entrepreneurial foresight, an existing warehouse was modified and extended. Also in this case, Glatt Ingenieurtechnik from Weimar was fully responsible for planning and implementation of process plants, building and equipment. Glatt Process Technologie GmbH from Binzen, the parent company of the Glatt Group, delivered a fluid bed Glatt Particle Coater Granulator GPCG 300.
This GPCG 300 was equipped with a larger filter and can be operated with an increased process gas quantity. This allows higher gas velocities in the process. The larger filter extends its service time and thus reduces the number of cleaning days. Hence this plant has the highest capacity out of the five batch-type fluid bed systems in Dresden. Three different process inserts allow different processes: fluid bed agglomeration with top spray nozzles, coating with the 32″ Wurster and coating with the 46″ Wurster.

In 2007, a ProCell 70 process insert was integrated in the GPCG 300 and the system extended by a screening-milling-cycle. Using this insert, for the first time IPC was able to offer the direct manufacturing of granules from liquid only by using the spray granulation processes. With the ProCell systems, IPC has the latest process technology from Glatt – the innovative spouted bed technology.

Spouted bed technology – ProCell systems

In contrast to fluid bed technology, the process gas does not enter the process chamber of spouted bed systems across the chamber’s whole cross section, but only through two slots. A process gas jet emerges in the center of the process chamber. Glatt owns the patent for the integration of spray nozzles in spouted bed systems and uses it in ProCell systems. In priciple, all fluid bed processes are also possible in the ProCell. However, the spouted bed technology offers additional advantages: Very fine products remain in the process due to the expansion of the process chamber. Very heavy products are moved through the high process gas velocity in the gap. The special geometry of the process chamber concentrates the product around the spray nozzle. This allows to reach equal spray rates with only 50% of the coating quantity of fluid bed systems. For continuous processes, this results in cutting the retention time by 50%.