Producing ethylene by oxidatively dehydrogenating ethane

A method for producing ethylene by oxidative dehydrogenation of ethane, comprising:

• providing a shell-and-tube reactor having reaction tubes extending between a first end and a second end, wherein a plurality of catalyst beds are disposed in each of said reaction tubes, and in each of said reaction tubes, a ratio of a total length of the plurality of catalyst beds between said first end and said second end to a diameter of each of said reaction tubes has a value between 150 and 400;
• and
• feeding a feed comprising ethane and oxygen to the shell-and-tube reactor operating under oxidative dehydrogenation conditions;
• wherein:
• the shell-and-tube reactor is operated at a linear velocity of 250 to 800 cm/s;
• the plurality of catalyst beds are configured such that the plurality of catalyst beds in each of the reaction tubes have a different catalyst activity;
• an average ratio of active catalyst mass to effective cooling surface for the plurality of catalyst beds in each of the reaction tubes is in a range between 1.5 and 5 kg/m2, wherein in at least one of the catalyst beds in each of the reaction tubes considered individually, a ratio of active catalyst mass to effective cooling surface is in the range between 1.5 and 5 kg/m2;
• and
• the average ratio of the active catalyst mass to the effective cooling surface for the plurality of catalyst beds in each of the reaction tubes is a quotient between a sum of the active catalyst masses in all of the respective catalyst beds and the sum of all inner surfaces of the reaction tube surrounding these catalyst beds, respectively.