Systems and methods for producing wash oil

1 . A method of processing a light fuel oil, the method comprising:

hydrogenating the light fuel oil to produce a hydrogenated intermediate stream; and

separating, in a separation unit, the hydrogenated intermediate stream to produce a C7+ stream; and

separating, in a C8 column, the C7+ stream to produce: a C7 to C8 fraction stream comprising toluene, p-, m-, and o-xylenes, and ethylbenzene and a wash oil stream comprising 90 to 99 wt. % aromatics.

2 . A method of processing a cracked distillate comprising 90 to 95 wt. % aromatics, the method comprising:

hydrogenating the cracked distillate and diluent comprising pyrolysis gas in a hydrogenation unit to produce a hydrogenated intermediate stream; and

separating, in a separation unit, the hydrogenated intermediate stream to remove C 4 to C 6 hydrocarbons, toluene and xylene from the hydrogenated intermediate stream to produce a wash oil stream configured to remove fouling from equipment, wherein the wash oil stream comprises 90 to 99 wt. % aromatics.

3 . The method of claim 2 , wherein the wash oil stream is configured to remove fouling from a compressor, a heat exchanger, or combinations thereof.

4 . The method of claim 2 , wherein the hydrogenating step is configured to saturate unsaturated hydrocarbons of the cracked distillate.

5 . The method of claim 2 , wherein the separation unit comprises one or more distillation columns.

6 . The method of claim 2 , wherein the compressor includes a cracked gas compressor.

7 . The method of claim 2 , wherein the wash oil stream is configured to remove fouling comprising one or more polymers formed by unsaturated hydrocarbons, indene, (methyl)-styrene, butadiene, dicyclopentadiene (DCPD), (methyl)-indene, or combinations thereof.

8 . The method of claim 2 , wherein the cracked distillate is produced via steam cracking of hydrocarbons.

9 . The method of claim 2 , wherein the pyrolysis gas is produced via condensation of cracked gas in quench water tower or cracked gas compressor.

10 . The method of claim 2 , wherein the cracked distillate and the pyrolysis gas stream are flowed into the hydrogenation unit at a weight flow rate ratio of 1:80 to 1:50.

11 . The method of claim 2 , wherein the hydrogenation unit is operated at an operating temperature of 50 to 175° C.

12 . The method of claim 2 , wherein the hydrogenation unit is operated at an operating pressure of 30 to 50 bar.

13 . The method of claim 2 , further comprising contacting wash oil from the wash oil stream to rinse off fouling from compressor internals and/or interstage coolers of a crack gas compressor.

14 . The method of claim 2 , wherein the diluent is configured to reduce negative impact of the cracked distillate on a catalyst used in the hydrogenating step.

15 . The method of claim 3 , wherein the diluent is configured to reduce negative impact of the cracked distillate on a catalyst used in the hydrogenating step.

16 . The method of claim 4 , wherein the diluent is configured to reduce negative impact of the cracked distillate on a catalyst used in the hydrogenating step.

17 . The method of claim 5 , wherein the diluent is configured to reduce negative impact of the cracked distillate on a catalyst used in the hydrogenating step.

18 . The method of claim 6 , wherein the diluent is configured to reduce negative impact of the cracked distillate on a catalyst used in the hydrogenating step.

19 . The method of claim 1 , wherein the separation unit is operates at an overhead temperature range of 70 to 90° C., a bottom boiling range of 140 to 170° C., and an operating pressure of 0.01 to 0.2 bara as a vacuum operated column.

20 . The method of claim 2 , wherein the toluene and xylene are removed in the separation unit operating at an overhead temperature range of 70 to 90° C., a bottom boiling range of 140 to 170° C., and an operating pressure of 0.01 to 0.2 bara as a vacuum operated column.