NANOMATERIAL-BASED SUBSTRATES FOR CHEMICAL SENSORS USING SURFACE ENHANCED RAMAN SPECTROSCOPY

• US 20170315061A1
• Filed: 05/02/2016
• Published: 11/02/2017
• Est. Priority Date: 05/02/2016
• Status: Active Grant

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Ventura, Darryl N., Murugesan, Sankaran, Khabashesku, Valery N., Suresh, Radhika
• Granted Patent: US 10,209,193 B2
• Time in Patent Office: Days
• CPC Class Codes: C30B 29/602 Nanotubes
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons

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.

Claims

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 carbon nanotubes filtered from a suspension and chemically cross-linked to form the first layer and a second layer of metal nanowires formed on top of 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 carbon nanotubes and a second layer of metal nanowires formed on top of 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 carbon nanotubes filtered from a suspension and chemically cross-linked to form the first layer and a second layer of metal nanowires formed on top of 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 carbon nanotubes are cross-linked in the first layer.

18. The method of claim 16, further comprising forming the first layer by filtering the carbon nanotubes from a suspension.

19. 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.

20. 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.