Determination of bed fluidity in fluid cokers

Claim 1

AN IMPROVED PROCESS FOR COKING HEAVY OILS WHICH COMPRISES CONTACTING A HEAVY OIL AT A COKING TEMPERATURE WITH A COKING BED FLUIDIZED SOLIDS WHEREBY SAID HEAVY OIL IS CONVERTED TO VAPORS AND RESIDUE WHICH IS DEPOSITED ON SAID SOLIDS, REMOVING SAID VAPORS OVERHEAD AS PRODUCT, MAINTAINING A FLUIDIZED COLUMN OF SAID SOLIDS IN A DRY CONDITION IN AN EXTERNAL, ELONGATED VERTICAL ZONE, SAID DRY SOLIDS HAVING BEEN HEATED TO A TEMPERATURE ABOVE THE COKING TEMPERATURE IN AN EXTERNAL HEATING ZONE, THE TOP PORTION OF SAID FLUIDIZED COLUMN BEING IN FLUID COMMUNICATION WITH THE UPPER PORTION OF SAID COKING BED, DETERMINING THE PRESSURE DIFFERENTIAL BETWEEN THE FLUIDIZED SOLIDS OF SAID COKING BED AND OF SAID EXTERNAL FLUIDIZED COLUMN AT POINTS OF SUBSTANTIALLY THE SAME ELEVATION, AND RESTRICTING THE CONCENTRATION OF LIQUID ON THE SOLIDS OF SAID COKING BED BY INCREASING THE SEVERITY OF THE OPERATION WHEN SAID PRESSURE DIFFERENTIAL INCREASES ABOVE A PREDETERMINED AMOUNT, WHEREBY BED BOGGING IS AVOIDED.