Abstract: A method for dispersing high molecular weight hydrocarbon material in an ethylene water quench tower, the method comprising the step of: introducing a deposit inhibiting amount of a dispersant into the ethylene water quench tower, the dispersant comprising a copolymer of a first monomer and a second monomer, the first monomer being selected from the group consisting of butyl methacrylate, lauryl methacrylate, stearyl methacrylate, and decyl methacrylate-2-ethylhexyl methacrylate, the second monomer being selected from the group consisting of diethyl-aminoethyl methacrylate, dimethyl amino-ethyl methacrylate, phenyl aminoethyl methacrylate, butyl aminoethyl methacrylate, and propyl aminoethyl methacrylate.

Abstract: A method for dispersing heavy hydrocarbons in an ethylene water quench tower, the method comprising the steps of: introducing an effective amount of a dispersant into the ethylene water quench tower, the dispersant comprising a copolymer of an .alpha.-olefin having from about 10 to about 36 carbon atoms and a maleic anhydride, wherein the rate ratio of the .alpha.-olefin to the maleic anhydride is from about 1:1 to about 5:5 and the molecular weight of the copolymer is from about 5,000 to about 100,000, the anhydride moieties of the copolymer being substantially intact.

Abstract: A method for dispersing heavy hydrocarbons in an ethylene process water stripper tower, the method comprising the steps of: introducing an effective amount of a dispersant into the ethylene water stripper, the dispersant comprising a copolymer of an .alpha.-olefin having from about 10 to about 36 carbon atoms and a maleic anhydride, wherein the rate ratio of the .alpha.-olefin to the maleic anhydride is from about 1:1 to about 5:5 and the molecular weight of the copolymer is from about 5,000 to about 100,000, the anhydride moieties of the copolymer being substantially intact.

Abstract: An improved process for inhibiting the formation and deposition of polymer-based fouling materials after caustic scrubbing of hydrocarbon streams contaminated with oxygenated compounds with a basic washing solution having a pH>7 comprising adding to the hydrocarbon stream after caustic scrubbing a sufficient amount for inhibiting formation and deposition of polymer-based fouling materials of a composition comprising at least one hydrazide compound characterized by the formula ##STR1## where R is selected from the group consisting of H, NHNH.sub.