Production of catalysts or catalyst carriers in the form of hollow beads

Claim 1

A PROCESS FOR PRODUCTION OF CATALYSTS AND CATALYST CARRIERS IN THE FORM OF HOLLOW BEADS HAVING CAVITIES COMMUNICATED WITH THE OUTER SIDES OF SAID BEADS BY PASSAGES IN SAID WALLS OF SAID BEADS, WHICH PROCESS COMPRISES SPRAYING INTO A SPRAY-DRYING TOWER THROUGH AT LEAST ONE NOZZLE OPENING OF 0.5-4 MM. AT A SPRAY PRESSURE OF 10-100 ATMOSPHERES A COMPOSITION FORMING SAID BEADS UPON DRYING IN SAID TOWER, SAID COMPOSITION BEING A HYDROGEL CONTAINING AT LEAST 30% WATER, A SUSPENSION OF A METAL COMPOUND IN WATER OR AN ORGANIC, VOLATILE LIQUID, A SOLUTION OF A METAL COMPOUND HAVING THIXOTROPIC PROPERTIES, OR A HYDROGEL IN ADMIXTURE WITH A METAL COMPOUND; CONCURRENTLY INTRODUCING INTO SAID TOWER A GAS HEATED TO 300*C.700*C. IN AN AMOUNT OF 4 TO 18 CUBIC METERS OF SAID GAS PER KILOGRAM OF SAID COMPOSITION; INCORPORATING INTO SAID COMPOSITION PRIOR TO SPRAYING THEREOF AN EXPANDING AGENT WHICH IS VAPORIZABLE OR DECOMPOSABLE INTO VAPOR OR GAS AT THE TEMPERATURE OF THE SPRAYED DROPLETS OF SAID COMPOSITION IN SAID TOWER; PROVIDING IN SAID TOWER A MEAN TEMPERATURE DROP OF AT LEAST 50*C. PER METER FROM SAID NOZZLE TO THE MIDDLE OF SAID TOWER; FORMING IN THE NEIGHBORHOOD OF SAID NOZZLE AN EXTENSIBLE BUT TOUGH SKIN ON THE SPRAYED DROPLETS; FORMING SAID DROPLETS INTO HOLLOW BEADS IN WHICH AT LEAST 80% HAVE DIAMETERS OF MORE THAN 90 MICRONS; AND BURSTING SAID SKIN OF SAID BEADS IN AT LEAST ONE PLACE TO PROVIDE PASSAGE TO THE INSIDE OF SAID HOLLOW TUBE.