Controlling inventory catalyst activity in moving bed systems

Claim 1

IN A MOVING BED SYSTEM IN WHICH A GRANULAR CATALYST IS GRAVITATED AS A COMPACT STREAM THROUGH A REACTION ZONE AT ELEVATED PRESSURE AND TEMPERATURE AND THROUGH A REGENERATION ZONE AND WHEREIN THE CATALYST IS PASSED DOWNWARDLY THROUGH AN ELONGATED GRAVITY FEED LEG AGAINST A RISING SEAL GAS, THE LEG BEING OF SUFFICIENT LENGTH TO FEED CATALYST SMOOTHLY INTO THE REACTION ZONE AGAINST THE ADVANCED PRESSURE THEREIN, THE IMPROVED METHOD OF MAINTAINING A SUBSTANTIALLY CONSTANT CATALYST ACTIVITY IN SAID REACTION ZONE WHICH COMPRISES: MEASURING A FUNCTION OF CATALYST ACTIVITY OF THE CATALYST IN SAID REACTION ZONE, SUPPLYING BOTH STEAM AND FLUE GAS TO THE CATALYST IN SAID GRAVITY FEED LEG, TO SEAL THE LEG AGAINST THE ESCAPE OF REACTANTS FROM SAID REACTION ZONE, INCREASING THE RELATIVE AMOUNT OF STEAM TO FLUE GAS IN SAID LEG IN RESPONSE TO AN INCREASE IN THE FUNCTION OF THE CATALYST ACTIVITY AND DECREASING THE RELATIVE AMOUNT OF STEAM TO FLUE GAS IN SAID LEG IN RESPONSE TO A DECREASE IN THE FUNCTION OF THE CATALYST ACTIVITY WHEREBY THE CATALYST ACTIVITY IS MAINTAINED SUBSTANTIALLY CONSTANT AT THE DESIRED CATALYST ACTIVITY.