Robust and sustainable chemical treatment for sulfur contaminants in feed natural gas

Patent metadata

Field	Value
Publication number	US-2023027117-A1
Application number	US-202117374652-A
Country	US
Kind code	A1
Filing date	Jul 13, 2021
Priority date	Jul 13, 2021
Publication date	Jan 26, 2023
Grant date	—

Abstract

A method for removing contaminants from a gas stream including contacting a gas stream comprising hydrocarbons and sulfur contaminants with a modified nanocomposite adsorbent. Also provided are compositions and processes for forming compositions of a modified nanocomposite adsorbent composition for removing sulfur contaminants from a hydrocarbon stream. Additionally, provided is system for removing sulfur impurities from a gaseous hydrocarbon stream, where the system includes a plurality of adsorbent vessels arranged in series, where the adsorbent vessels include an emulsion of a modified nanocomposite adsorbent composition.

First claim

What is claimed:

1 . A method for removing sulfur contaminants from a gas stream comprising:
contacting a gas stream comprising hydrocarbons and sulfur contaminants with a modified nanocomposite adsorbent, wherein the modified nanocomposite adsorbent comprises waste bauxite residue doped with zinc oxide nanoparticles, wherein the contacting of the gas stream with the modified nanocomposite adsorbent reduces an amount of sulfur contaminants in the gas stream.

2 . The method of claim 1 , wherein the gas stream is a natural gas comprising more than 50 wt % methane, ethane, propane, butane, and pentane, or combinations thereof.

3 . The method of claim 1 , where the sulfur contaminants are at least one or more selected from the group consisting of methyl mercaptans (CH 3 SH), dimethyl sulfide (CH 3 SCH 3 ), dimethyl disulfide (CH 3 SSCH 3 ), ethyl mercaptan (C 2 H 5 SH), isopropyl mercaptan (C 3 H 7 SH), isobutyl mercaptan (C 4 H 9 SH), N-butanethiol, carbonyl sulfides (COS), carbon disulfides (CS 2 ), H 2 S, HS − , S n 2 , or a combination thereof.

4 . The method of claim 1 , wherein the contacting the gas stream with the modified nanocomposite adsorbent reduces a concentration of one or more of the sulfur comprising impurities in the gas stream by 95% or more.

5 . The method of claim 1 , wherein the modified nanocomposite adsorbent is present in the form of a micro-emulsion.

6 . The method of claim 1 , wherein modified nanocomposite adsorbent comprises zinc oxide nanoparticles in an amount from 25 to 40 wt %, relative to the total weight of the modified nanocomposite adsorbent.

7 . The method of claim 1 , wherein the contacting the gas stream with a modified nanocomposite adsorbent comprises:
directing the gas stream to a plurality of sequential capturing traps, wherein each of the capturing traps comprises the modified nanocomposite adsorbent, wherein the gas stream maybe contacted with the modified nanocomposite adsorbent within each of the capturing traps.

8 . The method of claim 7 , wherein plurality of sequential capturing traps includes a first capturing trap, a second capturing trap, and a third capturing trap, and wherein the gas stream is dried in a drying tube at a stage between each capturing trap.

9 . The method of claim 8 , wherein first, second, and third capturing traps are operated at different temperatures.

10 . The method of claim 8 , wherein third capturing trap comprises the modified nanocomposite adsorbent as a mixture with ethanol.

11 . A modified nanocomposite adsorbent composition for removing sulfur contaminants from a hydrocarbon stream comprising:
zinc oxide nanoparticles disposed on a waste bauxite residue; wherein the waste bauxite residue comprises a first plurality of major minerals selected from the group consisting of calcium silicate, cancrinite, iron oxide, iron-oxide-hydroxide, or a combination thereof, wherein the waste bauxite residue comprises the first plurality of major minerals in an amount of at least 60% by weight with respect to the total weight of the bauxite waste residue.

12 . The modified nanocomposite adsorbent composition of claim 11 , wherein the modified nanocomposite adsorbent comprises zinc oxide nanoparticles in an amount from 25 to 40 wt %, relative to the total weight of the modified nanocomposite adsorbent.

13 . The modified nanocomposite adsorbent composition of claim 11 , wherein the modified nanocomposite adsorbent is present in the form of a micro-emulsion.

14 . The modified nanocomposite adsorbent composition of claim 11 , wherein the waste bauxite residue comprises a second plurality of minor minerals selected from the group of calcium carbonate (calcite), perovskite, grossite, quartz, gibbsite, or a combination thereof.

15 . The modified nanocomposite adsorbent composition of claim 11 , wherein the waste bauxite residue comprises a combination of a plurality of major elements and trace elements.

16 . The modified nanocomposite adsorbent composition of claim 15 , wherein the plurality of trace elements is selected from one or more of Ti, S, Zn, Mg, Sr, P, Cr, K, Mn, Ce, Pb, Ni, Th, or a combination thereof.

17 . The modified nanocomposite adsorbent composition of claim 16 , wherein the waste bauxite residue comprises the plurality of trace elements in an amount ranging from 2 to 6 wt %, relative to the total weight of the bauxite waste residue.

18 . The modified nanocomposite adsorbent composition of claim 16 , wherein the bauxite waste residue comprises Ti and S in an amount greater than 3 wt %, relative to the total weight of the bauxite waste residue.

19 . A process for forming an adsorbent for removing sulfur impurities from a hydrocarbon stream, the process comprising:
mixing a waste bauxite nanopowder with ethanol and an aqueous zinc nitrate solution to form a reaction mixture; increasing a temperature of the reaction mixture to a temperature of greater than 40° C. to 55° C. to obtain a slurry solution; and adding sodium hydroxide to the slurry solution to adjust a pH of the slurry solution to a pH in the range from about 13 to about 13.8 to convert the zinc nitrate to zinc oxide and forming a mercaptobauxinol adsorbent system (MAS) comprising a nanocomposite bauxite adsorbent doped with zinc oxide nanoparticles.

20 . The process of claim 19 , further comprising drying and pulverizing a waste bauxite residue to form the waste bauxite nanopowder.

21 . The process of claim 19 , further comprising mixing the MAS with ethanol to form an adsorbent mixture.

22 . The process of claim 21 , wherein the adsorbent mixture comprises from 5 wt % to 15 wt % ethanol.

23 . A system for removing sulfur impurities from a gaseous hydrocarbon stream, the system comprising:
a plurality of adsorbent vessels, wherein the plurality of vessels are arranged in series, and wherein each of the adsorbent vessels contains an emulsion of a modified bauxite adsorbent; and a gas distributor disposed within each adsorbent vessel and configured to introduce a gaseous hydrocarbon feed contaminated with sulfur impurities into the emulsion; a gas chromatography system configured to sample and measure a composition of a vapor product stream recovered from one or more of the plurality of adsorbent vessels.

24 . The system of claim 23 , further comprising a drying system configured to receive a vapor product from a last of the plurality of adsorbent vessels and to output a vapor product having a reduced water content.

25 . The system of claim 24 , further comprising a drying system disposed intermediate each of the plurality of adsorbent vessels, each drying system configured to receive a vapor product from one of the plurality of adsorbent vessels and to output a vapor product having a reduced water content to another of the plurality of adsorbent vessels.

26 . The system of claim 23 , wherein a final adsorbent vessel of the plurality of adsorbent vessels contains an emulsion of the modified nanocomposite adsorbent composition having a greater amount of ethanol as compared to the emulsions in the prior adsorbent vessels of the plurality of adsorbent vessels.

27 . The system of claim 23 , wherein the plurality of sequential adsorbent vessels consists of three adsorbent vessels.

Assignees

• Saudi Arabian Oil Co

Inventors

• Oduro Harry Daniel

Classifications

• B01D2256/24

  Hydrocarbons · CPC title

• B01D2257/306

  Organic sulfur compounds, e.g. mercaptans · CPC title

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• B01J2220/4806

  the starting material being of inorganic character · CPC title

• B01J20/28014

  characterised by their form · CPC title