Aromatic hydrocarbon inhibitor

Claim 1

A PROCESS FOR INHIBITING IN OIL REFINING APPARATUS DURING PETROLEUM REFINING OPERATIONS THE FORMATION OF ADHERENT COKE-LIKE DEPOSITS AND ADHERENT TENACIOUS SOFT, STICKY SLUDGES ON, AND THE ADHESION OF SAID DEPOSITS AND SAID SLUDGES TO, THE HOT METAL HEAT TRANSFER SURFACES OF A HEAT EXCHANGER IN SAID OIL REFINING APPARATUS BY A THERMALLY UNSTABLE PETROLEUM HYDROCARBON LIQUID, SAID HYDROCARBON LIQUID HAVING THE TENDENCY TO UNDERGO A CHEMICAL REACTION AT A TEMPERATURE IN THE RANGE OF ABOUT 225*F. TO ABOUT 800*F., SAID CHEMICAL REACTION MANIFESTING ITSELF IN THE FORM OF ADHERENT COKE-LIKE DEPOSITS AND ADHERENT SOFT, STICKY SLUDGES, SUCH AS ARE USUALLY FORMED DURING PASSAGE OF SAID HYDROCARBON LIQUID THROUGH SAID HEAT EXCHANGER AND IN CONTACT WITH THE HOT METAL SURFACES OF SAID HEAT EXCHANGER IN SAID OIL REFINING APPARATUS AT A TEMPERATURE IN THE RANGE OF ABOUT 225*F. TO ABOUT 800*F. COMPRISING (1) INCORPORATING IN SAID HYDROCARBON LIQUID PRIOR TO CONTACT WITH SAID METAL SURFACES OF SAID HEAT EXCHANGER IN SAID OIL REFINING APPARATUS AN ANTIFOULING AMOUNT OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 4-PHENYL CATECHOL, 4-TERT-BUTYL CATECHOL, ORTHOPHENYLENE DIAMINE, ORTHOAMINOPHENOL, AND CATECHOL, AND (2) HEATING SAID HYDROCARBON LIQUID HAVING INCORPORATED THEREIN SAID COMPOUND IN AN ANTIFOULING AMOUNT TO A TEMPERATURE IN THE RANGE OF ABOUT 255*F. TO ABOUT 800*F. BY CONTACT WITH SAID HOT METAL SURFACES OF SAID HEAT EXCHANGER IN SAID OIL REFINING APPARATUS.