Reduction of acids using metal naphthenate precipitation

Patent metadata

Field	Value
Publication number	US-2018201845-A1
Application number	US-201715722544-A
Country	US
Kind code	A1
Filing date	Oct 2, 2017
Priority date	Jan 17, 2017
Publication date	Jul 19, 2018
Grant date	—

Abstract

A process for reducing TAN of hydrocarbon feed oil, comprising:
a. combining alkaline earth metal, in an aqueous solution having a pH of 10 to 14, with the hydrocarbon feed oil to make a mixture; b. vigorously mixing the mixture; c. precipitating a metal-naphthenate salt; and d. removing the metal-naphthenate salt to reduce the TAN by 50 to 100%; wherein a weight ratio of the hydrocarbon feed oil to the aqueous solution is from 0.25:1 to 20:1. Also, a process for reducing TAN, comprising: a. combining an inorganic alkaline earth metal salt having a water solubility at 20° C. from 35 to 150 g/100 g water, in an aqueous solution having a pH of 10 to 14, to make a mixture; b. precipitating a metal-naphthenate salt; c. collecting the metal-naphthenate salt at an interface between an oil phase and an aqueous phase; and d. removing the metal-naphthenate salt.

First claim

It is claimed:

1 . A process for reducing an acid number of a hydrocarbon feed oil, comprising:
a) combining an alkaline earth metal, in an aqueous solution having a pH of 10 to 14, with the hydrocarbon feed oil having an initial TAN from 0.5 to 150 mg KOH/g to make a mixture; b) vigorously mixing the mixture; c) precipitating a metal-naphthenate salt in the mixture; and d) removing the metal-naphthenate salt to reduce the initial TAN by 50 to 100% in a treated feed oil; wherein a weight ratio of the hydrocarbon feed oil to the aqueous solution in the mixture is from 0.25:1 to 20:1.

2 . A process for reducing an acid number of a hydrocarbon feed oil, comprising:
a) combining an inorganic alkaline earth metal salt having a water solubility at 20° C. from 35 to 150 g/100 g water, in an aqueous solution having a pH of 10 to 14, with the hydrocarbon feed oil having an initial TAN from 0.5 to 150 mg KOH/g to make a mixture; b) precipitating a metal-naphthenate salt in the mixture; c) collecting the metal-naphthenate salt at an interface between an upper oil phase and a lower aqueous phase; and d) removing the metal-naphthenate salt to reduce the initial TAN by 50 to 100% in a treated feed oil.

3 . The process of claim 1 or claim 2 , wherein the combining and precipitating occur at a temperature from 10° C. to 150° C.

4 . The process of claim 1 or claim 2 , wherein the combining and precipitating occur at a pressure from 10 to 2000 kPa.

5 . The process of claim 1 , wherein the vigorously mixing occurs over a time from 15 seconds to 15,000 seconds.

6 . The process of claim 1 , wherein steps a) to d) are repeated and a total time for the vigorous mixing is reduced from 25 to 80% compared to a single step of the vigorously mixing. Using a multiple-step treatment, compared to a single step treatment, can reduce the total time for the vigorously mixing step significantly, such as from 25 to 80%

7 . The process of claim 1 or claim 2 , wherein the hydrocarbon feed oil is selected from the group consisting of a mineral crude oil, a synthetic crude oil, a distillate product, a straight run feed, an atmospheric distillation bottom, a vacuum distillation bottom, a vacuum gas oil, a biologically-derived oil, and mixtures thereof.

8 . The process of claim 1 , additionally comprising centrifuging the mixture to accumulate the metal-naphthenate salt in an oil/water interface prior to the removing step d).

9 . The process of claim 1 , additionally comprising applying an electrostatic field to the mixture to accumulate the metal-naphthenate salt in an oil/water interface prior to the removing step d).

10 . The process of claim 1 or claim 2 , wherein the process is performed in a desalter in a refinery.

11 . The process of claim 1 or claim 2 , additionally comprising adding a base to the aqueous solution to maintain a contacting pH above 9.0, wherein the base is selected from the group consisting of NaOH, KOH, NH 4 OH, and mixtures thereof.

12 . The process of claim 1 , wherein the alkaline earth metal is a calcium, a barium, a magnesium, or a combination thereof.

13 . The process of claim 2 , additionally comprising introducing an alkaline earth metal hydroxide to the aqueous solution.

14 . The process of claim 2 , wherein the inorganic alkaline earth metal salt is one or more of calcium chloride, calcium nitrate, calcium nitrite, calcium iodide, calcium bromide, magnesium chloride, magnesium bromide, barium chloride, and barium bromide.

15 . The process of claim 2 , wherein the aqueous solution comprises from 0.1 to 10 wt % of the inorganic alkaline earth metal salt.

16 . The process of claim 1 or claim 2 , wherein an end TAN of the treated feed oil is 1.0 mg KOH/g or less.

17 . The process of claim 1 or claim 2 , wherein the treated feed oil is produced upstream from a refinery or in the refinery.

18 . The process of claim 1 or claim 2 , wherein the treated feed oil is sent to a downstream FCC unit or another downstream hydroprocessing unit.

19 . The process of claim 1 or claim 2 , wherein the treated feed oil comprises less than 5000 wppm water.

20 . The process of claim 1 or claim 2 , additionally comprising dehydrating the treated feed oil.

Assignees

• Chevron Usa Inc

Inventors

• Li Lin

Classifications

• C10G57/00

  Treatment of hydrocarbon oils, in the absence of hydrogen, by at least one cracking process or refining process and at least one other conversion process · CPC title

• C10G2300/203

  Naphthenic acids, TAN · CPC title

• C10G19/02 Primary

  with aqueous alkaline solutions · CPC title