Superheated steam dryer Indirect

hot airconvectionconduction

GRELBEX indirect rotary dryers allow for the industrial drying of any powdered solid by indirectly exposing the product to hot gases. OPERATION: They are designed to guarantee reliable operation, high efficiency, maximum industrial availability, and low maintenance. These performance criteria make our rotary dryers a wise choice for drying powdered solids. Indirect rotary dryers consist of a cylinder (called a "drum" or "calender") that rotates slowly and steadily on two supports (called belts). This cylinder is driven by an electric or hydraulic motor. A network of tubes through which a heating fluid (often steam) circulates is integrated within the cylinder. As the cylinder rotates, the product slowly advances and comes into contact with the hot surface of the tubes, gradually losing its moisture as it is agitated. These dryers are designed for high throughput (several tens of tons per hour) with relatively high processing temperatures (from 100 to 300°C) and allow for the gentle and slow processing of solids. They are particularly well-suited for processing plant materials or food products. It should also be noted that these dryers are integrated into thermal processes that require optimization. Numerous options exist for recovering energy from the drying airflow after the process (recycling, condensation, cooling, separation, etc.). This allows for the optimization of the overall operation of the installation. APPLICATIONS: Chemical Industry • Drying of salts, crystals, and fine powders (sulfates, chlorides, carbonates, nitrates, etc.). • Drying of hygroscopic products (fertilizers, phosphates, pigments, catalysts). • Regeneration of solid solvents or adsorbents (e.g., zeolites, activated aluminas). Advantage: avoids contamination by combustion gases and preserves quality. Materials and Minerals Industry • Drying of clays, kaolin, gypsum, silica, or fine ceramic powders. • Drying of abrasive or sticky materials (clay slurry, refractory products, hydrated lime). • Gentle heat treatment before grinding or granulation. Advantage: Ideal for dirty or abrasive materials that would clog a direct dryer. Waste Treatment and Environment • Drying of industrial or municipal sludge, preventing the emission of polluting vapors. • Pre-drying before pyrolysis, incineration, or energy recovery. • Drying of hazardous or volatile products in a sealed and secure system. Advantage: Reduced sludge volume and transport costs – with no direct emissions of drying gases. Food and beverage industry • Drying of sunflower or soybean seeds or air-sensitive intermediates. • Drying of proteins, plant extracts, or enzymes when cross-contamination must be avoided. Advantage: Precise temperature control and a clean atmosphere.