Spray drying system

A system for drying wet material constituting a solid phase distributed in a fluid medium by means of evaporation of said medium, said system comprising:

• a feeding means for supplying said material in liquid state into the system, the liquid state selected from the group of states consisting of a solution, suspension, dispersion, paste, slurry, and a sludge,
• a means for atomizing by spraying the supplied liquid material so as to convert its initial state into a mist consisting of a plurality of droplets,
• a heating chamber provided with heating means for indirect heating of the interior thereof so as to evaporate the fluid medium from said mist of droplets generated by said means for atomizing,
• a product recovery and collecting means for collecting the solid particles of the final dried product, produced from said wet material, and for recovering said fluid medium from its evaporated state,
• a display and control means provided with sensors and instrumentation for controlling process variables, and
• an evacuation means, communicating with the interior of said heating chamber, for maintaining reduced pressure in the interior of said heating chamber so as to evaporate said fluid medium at temperatures lower than needed for its evaporation at normal pressure and to evacuate, away from the heating chamber, the moisture vapor generated during evaporation of said fluid medium, wherein said heating chamber is defined by side walls which extend along the longitudinal axis of the chamber and top and bottom extremities of the chamber, said atomizing means is mounted adjacent to the top extremity of said chamber, said product recovery and collecting means mounted adjacent to the bottom extremity of said chamber, and said evacuation means communicates with the interior of said heating chamber via said product recovery and collecting means;
• wherein said product recovery and collecting means comprises a recovery device selected from the group of devices consisting of a wet scrubber and a condenser, and a collection device formed as a member selected from the group of members consisting of a collecting bag and a cyclone system, and said evacuation means is formed as a vacuum pump;
• and a vapor sweeping means formed as a hollow tubular element mounted inside said heating chamber, extending along the longitudinal axis of said chamber, said hollow tubular element being provided with a plurality of openings so as to ensure communication of the interior of said element with the interior of said chamber, said vapor sweeping means being connected with said evacuation means.