Nanomaterial-based substrates for chemical sensors using surface enhanced raman spectroscopy

Patent metadata

Field	Value
Publication number	US-10209193-B2
Application number	US-201615143886-A
Country	US
Kind code	B2
Filing date	May 2, 2016
Priority date	May 2, 2016
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A method and apparatus for estimating a concentration of chemicals in a fluid flowing in a fluid passage is disclosed. A sample of the fluid is placed on a substrate comprising a first layer of carbon nanotubes and a second layer of metal nanowires. An energy source radiates the fluid sample with electromagnetic radiation at a selected energy level, and a detector measures an energy level of radiation emitted from the fluid sample in response to the electromagnetic radiation. A processor determines a Raman spectrum of the fluid sample from the energy level of the emitted radiation and estimates the concentration of a selected chemical in the fluid sample based on the Raman spectrum.

First claim

What is claimed is:

1. A method of estimating a concentration of chemicals in a fluid flowing in a fluid passage, comprising:
forming a substrate comprising a first layer made from unaligned carbon nanotubes filtered from a suspension and chemically cross-linked to form the first layer and a second layer of metal nanowires directly deposited on top of the first layer to coat the first layer;
placing a sample of the fluid flowing in the fluid passage on the substrate;
radiating the fluid sample with electromagnetic radiation at a selected energy level;
measuring a Raman spectrum emitted from the fluid sample in response to the electromagnetic radiation; and
estimating the concentration of a selected chemical in the sample fluid from the Raman spectrum.

2. The method of claim 1 , wherein the carbon nanotubes of the first layer form a carbon nanotube mat.

3. The method of claim 1 , wherein the metal nanowires of the second layer coat the carbon nanotubes of the first layer.

4. The method of claim 1 , wherein the substrate is a flexible substrate.

5. The method of claim 1 , wherein the selected chemical is at least one of (i) an amine; (ii) a sulfur compound; (iii) an amino alcohols; and (iv) an amino thiol.

6. The method of claim 1 , wherein the selected chemical is monoethanolamine (MEA).

7. The method of claim 1 , wherein the second layer comprises at least one of: (i) silver nanowires; (ii) metal nanowires and metal nanoparticles; and (iii) silver nanowires and metal nanoparticles.

8. The method of claim 1 , wherein the fluid passage is at least one of: (i) a fluid passage at a downstream location of a completion process; (ii) a fluid passage at a downstream location of a crude wash process; and (iii) a fluid passage of an overhead tower of a petroleum refinery.

9. An apparatus for estimating a concentration of a chemical in a fluid passage, comprising:
a substrate comprising a first layer of unaligned carbon nanotubes and a second layer of metal nanowires directly deposited on top of the first layer to coat the first layer, the carbon nanotubes of the first layer being filtered from a suspension and chemically cross-linked;
an energy source for directing a beam of electromagnetic energy at a selected energy level at a fluid sample from the fluid passage on a surface of the substrate;
a detector for measuring an energy level of radiation emitted from the fluid sample in response to the beam of electromagnetic energy; and
a processor configured to:
determine a Raman spectrum of the fluid sample from the energy level of the emitted radiation, and
estimate the concentration of a selected chemical in the fluid sample based on the Raman spectrum.

10. The apparatus of claim 9 , wherein the carbon nanotubes of the first layer form a carbon nanotube mat.

11. The apparatus of claim 9 , wherein the metal nanowires of the second layer are deposited onto the first layer.

12. The apparatus of claim 9 , wherein the substrate is a flexible substrate.

13. The apparatus of claim 9 , wherein the selected chemical is at least one of (i) an amine; (ii) a sulfur compound; (iii) an amino alcohols; (iv) an amino thiol; and (v) monoethanolamine (MEA).

14. The apparatus of claim 9 , wherein the metal nanowires further comprise at least one of: (i) silver nanowires; (ii) metal nanowires and metal nanoparticles; and (iii) silver nanowires and metal nanoparticles.

15. The apparatus of claim 9 , wherein the fluid passage is one of: (i) a fluid passage at a downstream location of a completion process; (ii) a fluid passage at a downstream location of a crude wash process; and (iii) a fluid passage of an overhead tower of a petroleum refinery.

16. A method for characterizing a corrosive chemical in a fluid flowing in a fluid passage, comprising:
forming a substrate comprising a first layer made from unaligned carbon nanotubes filtered from a suspension and chemically cross-linked to form the first layer and a second layer of metal nanowires directly deposited on top of the first layer to coat the first layer;
placing a sample of the fluid on the substrate;
radiating the fluid sample with electromagnetic radiation at a selected energy level;
measuring a Raman spectrum emitted from the fluid sample in response to the electromagnetic radiation; and
characterizing a concentration of the corrosive chemical in the fluid sample from the Raman spectrum.

17. The method of claim 16 , wherein the corrosive chemical is at least one selected from the group consisting of: (i) dimethylethanolamine; (ii) methylamine; (iii) methyl diethanolamine; and (iv) monoethanolamine.

18. The method of claim 16 , further comprising adding a corrosion inhibitor to the fluid flowing in the fluid passage based on the concentration of the corrosive chemical.

Assignees

• Ventura Darryl N
• Murugesan Sankaran
• Khabashesku Valery N
• Suresh Radhika
• Baker Hughes A Ge Co Llc

Inventors

• Ventura Darryl N
• Murugesan Sankaran
• Khabashesku Valery N
• Suresh Radhika

Classifications

• G01N21/658 Primary

  enhancement Raman, e.g. surface plasmons · CPC title

• G01J3/44

  Raman spectrometry; Scattering spectrometry {; Fluorescence spectrometry} · CPC title

• C30B29/602

  Nanotubes · CPC title