Catalytic desulphurisation of petroleum hydrocarbons

Claim 1

A PROCESS FOR THE HYDROCATALYTIC DESULPHURISATION OF A NAPHTHENE- AND SULPHUR-CONTAINING PETROLEUM FEEDSTOCK, WHICH COMPRISES CHARGING A SYSTEM OF (N) REACTION ZONES, N HAVING A VALUE OF AT LEAST 3, WITH A SULPHUR-RESISTANT DEHYDROGENATION-HYDROGENATION CATALYST, THE TOTAL CATALYST CHARGE IN SAID SYSTEM BEING DISTRIBUTED SUBSTANTIALLY EQUALLY AMONG SAID ZONES CONTINOUSLY PASSING SUBSTANTIALLY EQUAL PROPORTIONS OF THE FEEDSTOCK IN VAPOR FORM IN ADMIXTURE WITH HYDROGEN SIMULTANEOUSLY AND AT SUBSTANTIALLY EQUAL SPACE VELOCITY TO (N-1) REACTION ZONES OF SAID SYSTEM, WHILE MAINTAINING ONE REACTION ZONE OF SAID SYSTEM ON A STAND-BY BASIS; CONTACTING SAID MIXTURE IN THE SAID (N-1) REACTION ZONES WITH SAID CATALYST AT AN ELEVATED TEMPERATURE AND PRESSURE SUCH THAT SUFFICIENT HYDROGEN IS PRODUCED BY DEHYDROGENATION OF NAPHTHENE HYDROCARBONS CONTAINED IN THE FEEDSTOCK TO EFFECT THE CONVERSION OF SULPHUR COMPOUNDS CONTAINED IN THE FEEDSTOCK INTO HYDROGEN SULPHIDE AND TO MAINTAIN PRESSURE IN SAID (N-1) REACTION ZONES; RECYCLING SAID HYDROGENRICH GAS MIXTURE INTO ADMIXTURE WITH THE INCOMING FEEDSTOCK FOR PASSAGE TO SAID (N-1) REACTION ZONES SO AS TO CONSTITUTE THE WHOLE OF THE HYDROGEN SUPPLIED TO SAID (N-1) REACTION ZONES; RECOVERING A DESULPHURIZED PRODUCT FROM SAID PRODUCTS OF SAID (N-1) REACTION ZONES; DISCONTINUING THE PASSAGE OF SAID MIXTURE TO EACH OF SAID (N-1) REACTION ZONES IN TURN AFTER PERIODS OF TIME EACH EQUAL TO THE TOTAL DESIRED ON-STREAM TIME DIVIDED BY (N-1) OF THE CATALYST CHARGE IN SAID SYSTEM; REPLACING IN SEQUENCE EACH OF SAID (N-1) REACTION ZONES, WITH THE REACTION ZONE OF SAID SYSTEM WHICH IS THEN ON A STAND-BY BASIS; PASSING SAID MIXTURE TO SAID (N-1) REACTION ZONES AS SO REPLACED; AND, REGENERATING THE CATALYST IN THE REACTION ZONE AS AND FROM WHICH THE PASSAGE OF SAID MIXTURE THERETO IS DISCONTINUED WHEREBY ONE REACTION ZONE OF SAID SYSTEM WILL ALWAYS BE MAINTAINED ON SAID STAND-BY BASIS TO REPLACE THE ZONE NEXT IN SEQUENCE FOR REMOVAL FROM THE SYSTEM FOR REGENERATION.