FLSmidth Minerals has over a quarter of a century of experience with gas suspension calciners (GSC) for the cement industry. Most of the processes in a GSC plant, such as drying, preheating, calcination, and cooling, are performed in gas suspension. Consequently, the plant consists of stationary equipment with optimum thermal insulation and very few moving components.
The gas suspension calciner uses the entrained-bed principle, which ensures a solids retention time of a few seconds. The GSC is characterized by a low solids concentration, gas velocities in the range of 2-5 m/sec, and a low pressure drop. The amount of material in the system is negligible, which means that after a few minutes of operation the product will conform to specifications. There is no loss of material or quality during start up and shutdown as both operations are simple and fast. The vertical arrangement of cyclones, ensuring gravity flow of solids, eliminates the need for pneumatic transport of materials within the plant.
The cyclone separators used in the GSC system are of the FLS-LP type with the following unique features.
- Large gas outlet reducing pressure drop
- Special inlet geometry ensuring high separating efficiency without central pipe
- Insulating block lining minimizing surface heat loss
- Sloping inlet bottom preventing material accumulation
- Small cyclone diameter reducing cross-sectional tower dimension