Corrosion inhibitor compositions and methods for inhibiting corrosion on a metal surface exposed to a hydrocarbon fluid are provided. The corrosion inhibition compositions can include a corrosion inhibitor, such as 3-dimethylamino benzoic acid, 4-dimethylamino benzoic acid, or 2,5-dihydroxyterephthalic acid. The corrosion inhibitor composition can further comprise dimethyl sulfoxide, and heavy aromatic naphtha. The corrosion inhibitor composition can be phosphate-free and can inhibit naphthenic acid corrosion. In the methods, a corrosion inhibitor composition is added to the hydrocarbon fluid exposed to the metal surface to prevent or inhibit corrosion on the metal surface, including naphthenic acid corrosion.

Corrosion inhibitor compositions and methods for inhibiting corrosion on a metal surface exposed to a hydrocarbon fluid are provided. The corrosion inhibition compositions can include a corrosion inhibitor, such as 3-dimethylamino benzoic acid, 4-dimethylamino benzoic acid, or 2,5-dihydroxyterephthalic acid. The corrosion inhibitor composition can further comprise dimethyl sulfoxide, and heavy aromatic naphtha. The corrosion inhibitor composition can be phosphate-free and can inhibit naphthenic acid corrosion. In the methods, a corrosion inhibitor composition is added to the hydrocarbon fluid exposed to the metal surface to prevent or inhibit corrosion on the metal surface, including naphthenic acid corrosion.

Described herein are systems and methods for control of an overhead crude section of a hydrocarbon refining process. In one aspect, the method comprises monitoring a plurality of operating conditions of an overhead crude section of a refinery; determining hydrogen chloride and amine conditions of the overhead crude section of the refinery at current operating conditions of the overhead crude section; determining a plurality of fields of action by simulating a variation of one or more of the plurality of conditions; determining a risk indicator of salting for each of the plurality of fields of action; and providing a recommended change in operation of the overhead crude section to one of the plurality of fields of action while adhering to one or more constraints.

Described herein are systems and methods for control of an overhead crude section of a hydrocarbon refining process. In one aspect, the method comprises monitoring a plurality of operating conditions of an overhead crude section of a refinery; determining hydrogen chloride and amine conditions of the overhead crude section of the refinery at current operating conditions of the overhead crude section; determining a plurality of fields of action by simulating a variation of one or more of the plurality of conditions; determining a risk indicator of salting for each of the plurality of fields of action; and providing a recommended change in operation of the overhead crude section to one of the plurality of fields of action while adhering to one or more constraints.

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

Disclosed are molybdenum-containing complexes used in compositions and methods for inhibiting or reducing high temperature corrosion in petroleum refineries.

Fouling in a hydrocarbon refining process is reduced by adding to a crude hydrocarbon for a refining process, an additive combination including: (A) a polyalkenyl-substituted carboxylic acid or anhydride, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent,
where the mass:mass ratio of (A) to (B) is in the range of 10:1 to 1:10, and the treat rate of the additive combination is in the range of 5 to 1000 ppm by mass.

Fouling in a hydrocarbon refining process is reduced by adding to a crude hydrocarbon for a refining process, an additive combination including: (A) a polyalkenyl-substituted carboxylic acid or anhydride, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent,
where the mass:mass ratio of (A) to (B) is in the range of 10:1 to 1:10, and the treat rate of the additive combination is in the range of 5 to 1000 ppm by mass.

Treatment of crude oil with basic ionic liquids (ILs), results in scavenging of any hydrochloric acid (HCl) that is present to remove the HCl. The IL is a quaternary ammonium compound having the formula R.sub.4N.sup.+X.sup. or R.sub.3N.sup.+RN.sup.+R.sub.3, where R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1-22 carbon atoms, R is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and where X.sup. is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkyl-carbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms. The ILs are introduced into the crude oil after the refinery desalters and before the crude distillation tower to prevent or inhibit HCl from distilling to the crude tower overhead.

Treatment of crude oil with basic ionic liquids (ILs), results in scavenging of any hydrochloric acid (HCl) that is present to remove the HCl. The IL is a quaternary ammonium compound having the formula R.sub.4N.sup.+X.sup. or R.sub.3N.sup.+RN.sup.+R.sub.3, where R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1-22 carbon atoms, R is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and where X.sup. is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkyl-carbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms. The ILs are introduced into the crude oil after the refinery desalters and before the crude distillation tower to prevent or inhibit HCl from distilling to the crude tower overhead.