Catalyst Preparation and Testing for Catalytic Combustion of Chloromethanes

Abstract

The catalytic combustion of methylenechloride, carbontetrachloride, and chloroform, three of the chloromethanes, was investigated on metal oxide catalysts prepared on the monolith support or on the spherical alumina pellets. The prepared catalysts were tested for methylenechloride and carbontetrachloride at the different temperatures and at varying GHSV values with an excess air ratios of 216% and 3100%, respectively. The catalyst having the composition of 15% Cr₂O₃, 5% Ce₂O₃ and 80% y-Al₂O₃ on the monolith was found to be ultimate due to the complete destruction of methylenechloride and to the highest mechanical stability. The operating conditions were proposed as 77778 h^-1 for the GHSV, 216% for the excess air and 400–500 °C for the temperature range to combust methylenechloride completely. However the catalyst with a different active part composition (18% Cr₂O₃, 2% Ce₂O₃) satisfied nearly complete destruction of carbontetrachloride. The operating conditions were 5702 h^-1 for the GHSV, 3100% for the excess air ratio and 800 °C for the temperature to combust carbontetrachloride. The catalytic oxidation of chloroform was investigated by the catalyst having the composition of 18% Cr₂O₃, 2% of Ce₂O₃ on monolith. The excess air was kept at a value of 4077%. The reactor temperature was changed between 200 and 300 °C.