| 摘要 |
PURPOSE:To activate the catalyst in the catalytic isomerization of xylene in the presence of hydrogen using a Pd-containing crystalline aluminosilicate catalyst, by interrupting the reaction, introducing an oxygen-containing gas through the catalyst bed, and heating at a specific temp. CONSTITUTION:Xylene is isomerized by contacting a raw material containing a mixture of xylene isomers including ethylbenzene with a Pd-containging crystalline aluminosilicate catalyst (e.g. zeolite ZSM-5) in the presence of hydrogen. In the above process, the catalyst covered with deposited carbonaceous material is activated by contacting with an oxygen-containing gas at an elevated temp. The activation is carried out by raising the inlet temp. of the oxygen-containing gas slowly from <=200 deg.C to 330-390 deg.C (pref. from 150 deg.C to 370 deg.C) keeping the max. temp. in the catalyst bed below 400 deg.C while controlling the hot-spot temp. in the catalyst bed always below 50 deg.C (esp. below 30 deg.C) during combustion of the carbonaceous material, and then reducing the catalyst with hydrogen. |
