SPENT ZINC CHLORIDE CATALYST IS REGENERATED BY COMBUSTION IN THE VAPOR PHASE IN THE PRESENCE OF A FLUIDIZED REFRACTORY SOLID SUCH AS SILICA SAND. USE OF A NEAR-STOICHIOMETRIC AMOUNT OF AIR RESULTS IN SUBSTANTIALLY COMPLETE REMOVAL OF SULFUR, NITROGEN AND CARBON IMPURITIES, WHILE USE OF ABOUT 40 TO 60% OF THE STOICHIOMETRIC AMOUNT OF AIR RESULTS IN PRODUCTION OF A LOW-SULFUR FUEL GAS.