METHOD OF PARTIAL DEALUMINIZATION OF ZEOLITIC CATALYST.

摘要

A method of partial dealuminization of a zeolitic catalyst by steaming, which comprises passing steam through a zeolitic catalyst bed in a reactor to bring the catalyst into contact with the steam for 0.1 to 50 hours under the temperature distribution condition that satisfies the following requisites (1) and (2): (1) 500 DEG C </= To </= T </= T2 </= 700 DEG C; To: temperature of feed steam ( DEG C); T2: maximum temperature of catalyst bed ( DEG C); T: average temperature of catalyst bed ( DEG C); T = (a), Ti: time-averaged catalyst temperature of i-th block when catalyst bed is divided into n equal blocks along the direction of steam passage ( DEG C). (2) cv((T) x 1,000 </= 10; cv(T): coefficient of variation of time-averaged catalyst temperature; cv(T) = s(T)/T; s(T): standard deviation of time- averaged catalyst temperature; s(T)<2>: dispersion of time-averaged catalyst temperature; S(T)<2> = (b). The invention method provides a zeolitic catalyst which has a uniform catalytic activity and can retain its activity stably for long when used as a catalyst. <IMAGE>