An antifoulant composition for a gas processing plant, the composition having a phosphonothioic ester; a non-ionic surfactant; and a film forming surfactant. A method for inhibiting fouling in a gas processing plant, the method (a) providing an antifoulant composition; and (b) adding the antifoulant composition to a hydrocarbon stream present in a gas processing plant.

An antifoulant composition for a gas processing plant, the composition having a phosphonothioic ester; a non-ionic surfactant; and a film forming surfactant. A method for inhibiting fouling in a gas processing plant, the method (a) providing an antifoulant composition; and (b) adding the antifoulant composition to a hydrocarbon stream present in a gas processing plant.

Treatment compositions for neutralizing acidic species and reducing hydrochloride and amine salts in a fluid hydrocarbon stream are disclosed. The treatment compositions may comprise at least one amine with a salt precipitation potential index of equal to or less than about 1.0. Methods for neutralizing acidic species and reducing deposits of hydrochloride and amine salts in a hydrocarbon refining process are also disclosed. The methods may comprise providing a fluid hydrocarbon stream and adding a treatment composition to the fluid hydrocarbon stream. The treatment compositions used may have a salt precipitation potential index of equal to or less than about 1.0 and comprise either water-soluble or oil-soluble amines.

Treatment compositions for neutralizing acidic species and reducing hydrochloride and amine salts in a fluid hydrocarbon stream are disclosed. The treatment compositions may comprise at least one amine with a salt precipitation potential index of equal to or less than about 1.0. Methods for neutralizing acidic species and reducing deposits of hydrochloride and amine salts in a hydrocarbon refining process are also disclosed. The methods may comprise providing a fluid hydrocarbon stream and adding a treatment composition to the fluid hydrocarbon stream. The treatment compositions used may have a salt precipitation potential index of equal to or less than about 1.0 and comprise either water-soluble or oil-soluble amines.

Methods for producing olefins through hydrocarbon steam cracking include passing a hydrocarbon feed that includes one or more hydrocarbons to a hydrocarbon cracking unit and passing one or more sulfur-containing compounds to the hydrocarbon cracking unit. The sulfur- containing compounds include at least hydrogen sulfide gas, and a flow rate of the sulfur- containing compounds to the hydrocarbon cracking unit is sufficient to produce a molar concentration of elemental sulfur in the hydrocarbon cracking unit of from 10 ppm to 200 ppm. The methods include cracking the hydrocarbon feed in the hydrocarbon cracking unit to produce a cracker effluent and contacting the cracker effluent with a quench fluid in a quench unit to produce at least a cracked gas and a first pygas. The first pygas has a concentration of carbon disulfide less than 50 ppmw based on the total mass flow rate of the first pygas.

In one embodiment, an alkylphenol copolymer is disclosed wherein the copolymer comprises at least one alkylphenol monomer and the alkylphenol copolymer exhibits the following: an oscillation displacement Θ of greater than 0 at a temperature of −5° C. in a first oscillation temperature sweep and an oscillation displacement Θ in a second oscillation temperature sweep within 25% of the oscillation displacement Θ in the first oscillation temperature sweep at a temperature of −5° C. In a further embodiment, a petroleum composition is disclosed wherein the composition comprises a petroleum source and a macromolecular compound wherein the macromolecular compound exhibits the following: an oscillation displacement Θ of greater than 0 at a temperature of −10° C. in a first oscillation temperature sweep, and an oscillation displacement Θ in a second oscillation temperature sweep within 25% of the oscillation displacement Θ in the first oscillation temperature sweep at a temperature of −10° C.

In one embodiment, an alkylphenol copolymer is disclosed wherein the copolymer comprises at least one alkylphenol monomer and the alkylphenol copolymer exhibits the following: an oscillation displacement Θ of greater than 0 at a temperature of −5° C. in a first oscillation temperature sweep and an oscillation displacement Θ in a second oscillation temperature sweep within 25% of the oscillation displacement Θ in the first oscillation temperature sweep at a temperature of −5° C. In a further embodiment, a petroleum composition is disclosed wherein the composition comprises a petroleum source and a macromolecular compound wherein the macromolecular compound exhibits the following: an oscillation displacement Θ of greater than 0 at a temperature of −10° C. in a first oscillation temperature sweep, and an oscillation displacement Θ in a second oscillation temperature sweep within 25% of the oscillation displacement Θ in the first oscillation temperature sweep at a temperature of −10° C.

A method of oxygen scavenging, the method (i) providing an oxygen scavenger composition; and (ii) adding the oxygen scavenger composition to an aqueous feed and/or a hydrocarbon feed of a hydrocarbon processing system.

A method of oxygen scavenging, the method (i) providing an oxygen scavenger composition; and (ii) adding the oxygen scavenger composition to an aqueous feed and/or a hydrocarbon feed of a hydrocarbon processing system.

Disclosed are molybdenum-containing complexes used in compositions and methods for inhibiting or reducing the deposition of foulant on equipment.