A process for treating a hydrocarbon stream to remove polynuclear aromatic (PNA) and heavy polynuclear aromatic (HPNA) compounds includes contacting the hydrocarbon stream with an adsorbent in an adsorption unit to adsorb the PNA and HPNA compounds onto the adsorbent to produce a treated hydrocarbon stream and regenerating the adsorbent. Regenerating the adsorbent may include contacting the adsorbent with a solvent comprising a disulfide oil, such as a disulfide oil effluent from a mercaptan oxidation unit. The solvent comprising the disulfide oil desorbs the PNA and HPNA compounds from the adsorbent into the solvent to produce a desorption effluent. The treated hydrocarbon stream can be passed to a hydrocracking unit that hydrocracks the treated hydrocarbon stream to produce a hydrocracker effluent that includes greater value petrochemical products or intermediates.

Methods and systems for reducing sulfur content in crude oil are provided. The methods and systems apply a first alkaline aqueous solution to crude oil to produce alkaline-treated crude oil, apply an acid aqueous solution to the alkaline-treated crude oil to produce acid-treated crude oil, apply a second alkaline aqueous solution to the acid-treated crude oil to produce neutralized crude oil; and separate residual water that contains sulfur from the neutralized crude oil to produce treated crude oil that has less sulfur content than the crude oil before the treatment.

Methods and systems for reducing sulfur content in crude oil are provided. The methods and systems apply a first alkaline aqueous solution to crude oil to produce alkaline-treated crude oil, apply an acid aqueous solution to the alkaline-treated crude oil to produce acid-treated crude oil, apply a second alkaline aqueous solution to the acid-treated crude oil to produce neutralized crude oil; and separate residual water that contains sulfur from the neutralized crude oil to produce treated crude oil that has less sulfur content than the crude oil before the treatment.

A process for treating a hydrocarbon stream to remove polynuclear aromatic (PNA) and heavy polynuclear aromatic (HPNA) compounds includes contacting the hydrocarbon stream with an adsorbent in an adsorption unit to adsorb the PNA and HPNA compounds onto the adsorbent to produce a treated hydrocarbon stream and regenerating the adsorbent. Regenerating the adsorbent may include contacting the adsorbent with a solvent comprising a disulfide oil, such as a disulfide oil effluent from a mercaptan oxidation unit. The solvent comprising the disulfide oil desorbs the PNA and HPNA compounds from the adsorbent into the solvent to produce a desorption effluent. The treated hydrocarbon stream can be passed to a hydrocracking unit that hydrocracks the treated hydrocarbon stream to produce a hydrocracker effluent that includes greater value petrochemical products or intermediates.

A process for treating a hydrocarbon stream to remove polynuclear aromatic (PNA) and heavy polynuclear aromatic (HPNA) compounds includes contacting the hydrocarbon stream with an adsorbent in an adsorption unit to adsorb the PNA and HPNA compounds onto the adsorbent to produce a treated hydrocarbon stream and regenerating the adsorbent. Regenerating the adsorbent may include contacting the adsorbent with a solvent comprising a disulfide oil, such as a disulfide oil effluent from a mercaptan oxidation unit. The solvent comprising the disulfide oil desorbs the PNA and HPNA compounds from the adsorbent into the solvent to produce a desorption effluent. The treated hydrocarbon stream can be passed to a hydrocracking unit that hydrocracks the treated hydrocarbon stream to produce a hydrocracker effluent that includes greater value petrochemical products or intermediates.

In an aspect, a method is disclosed that includes contacting a composition with an aqueous solution to yield a mixture, where the composition includes one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil, about 5 wt. % or more of free fatty acids, about 10 wppm or more of total metals, about 8 wppm or more phosphorus, about 20 wppm or more of nitrogen, and the aqueous solution includes ((NH.sub.4).sub.2H.sub.2EDTA, (NH.sub.4).sub.4EDTA, a monoammonium salt of diethylenetriaminepentaacetic acid, a diammonium salt of diethylenetriaminepentaacetic acid, a triammonium salt of diethylenetriaminepentaacetic acid, a tetraammonium salt of diethylenetriaminepentaacetic acid, (NH.sub.4).sub.5DTPA, a combination of citric acid and Na.sub.4EDTA, a combination of citric acid and Na.sub.2H.sub.2EDTA, a combination of citric acid and a monosodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a disodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a trisodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a tetrasodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and Na.sub.5DTPA, or a combination of any two or more thereof, where the method further includes centrifuging the mixture to yield a first treated composition, wherein the first treated composition has less total metals and less phosphorus than the composition.

Disclosed are a pretreatment method and system for a fraction oil for the production of alkylbenzene, the method comprising: adding a fraction oil, a weak base solution and an inorganic salt solution into a reactor, and leaving same to stand and layering same after the reaction is complete; adding water and an inorganic salt solution into an oil phase for washing with water; extracting same with a polar solvent having a high boiling point, and then adsorbing same with an adsorbent to separate oxygen-containing compounds in the neutral fraction oil; sending the extraction agent containing the oxygen-containing compounds to an extraction agent recovery unit; and then sending the neutral fraction oil to an alkylation reactor for a reaction.

Disclosed are a pretreatment method and system for a fraction oil for the production of alkylbenzene, the method comprising: adding a fraction oil, a weak base solution and an inorganic salt solution into a reactor, and leaving same to stand and layering same after the reaction is complete; adding water and an inorganic salt solution into an oil phase for washing with water; extracting same with a polar solvent having a high boiling point, and then adsorbing same with an adsorbent to separate oxygen-containing compounds in the neutral fraction oil; sending the extraction agent containing the oxygen-containing compounds to an extraction agent recovery unit; and then sending the neutral fraction oil to an alkylation reactor for a reaction.

A treatment process for preparing a remediated liquid from a contaminated liquid originally containing more than 5 ppm hydrogen sulfide (H.sub.2S) and substantially without formation of precipitate, includes steps of steps of adding an aqueous solution containing at least one hydroxide compound at a collective concentration of 35-55 wt % to the contaminated liquid to achieve a concentration of 125-5000 ppm of the hydroxide compounds in the contaminated liquid, adding a fulvic acid and/or a humic acid to the contaminated liquid to achieve a concentration of 0.01-10 ppm of the acid(s) in the contaminated liquid, and dispersing the aqueous solution and the at least one organic acid in the contaminated liquid and allowing the aqueous solution and the at least one organic acid to react with the contaminated liquid for a period of time until a concentration of hydrogen sulfide in the contaminated liquid is reduced to ≤5 ppm.

A treatment process for preparing a remediated liquid from a contaminated liquid originally containing more than 5 ppm hydrogen sulfide (H.sub.2S) and substantially without formation of precipitate, includes steps of steps of adding an aqueous solution containing at least one hydroxide compound at a collective concentration of 35-55 wt % to the contaminated liquid to achieve a concentration of 125-5000 ppm of the hydroxide compounds in the contaminated liquid, adding a fulvic acid and/or a humic acid to the contaminated liquid to achieve a concentration of 0.01-10 ppm of the acid(s) in the contaminated liquid, and dispersing the aqueous solution and the at least one organic acid in the contaminated liquid and allowing the aqueous solution and the at least one organic acid to react with the contaminated liquid for a period of time until a concentration of hydrogen sulfide in the contaminated liquid is reduced to ≤5 ppm.