# US 10,767,980 B2 · Method of determining diametrical growth of reformer tubes

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- Number: US 10,767,980 B2
- Document ID: US10767980B2
- Status: Granted
- Kind: B2
- Application number: 16/274,414
- Filed: 2019-02-13
- Published: 2020-08-13
- Granted: 2020-09-08
- Earliest claimed: 2019-02-13
- Assignees: Praxair Technology, Inc.
- Applicants: Apratim Bhattacharya; Kang Xu; Troy M Raybold; Minish Mahendra Shah
- Inventors: Apratim Bhattacharya; Kang Xu; Troy M Raybold; Minish Mahendra Shah
- Web page: https://patentgrep.com/patent/US10767980B2

## CPC

- B01J 8/062: {being installed in a furnace}
- G01B 11/16: for measuring the deformation in a solid, e.g. optical strain gauge
- B01J 8/0285: {Heating or cooling the reactor (for tubular reactors in furnaces B01J8/062)}
- G01B 11/12: internal diameters
- G01L 1/04: by measuring elastic deformation of gauges, e.g. of springs
- G01N 25/00: Investigating or analyzing materials by the use of thermal means (G01N3/00 - G01N23/00 take precedence)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

The present invention relates to modifying a reformer tube to facilitate regular tube inspections to assess the service life and subsequently predict its remaining life accurately.

## Claims

### Claim 1

A method for determining diametrical growth in a reformer tube comprising:
providing a reformer tube having at least one machined, circumferential reference marking or groove on the inside of the reformer tube located in a region of low reformer tube creep growth;
measuring a first set of inside diameters at a time t1 along a predefined length of the reformer tube that contains the circumferential reference marking(s) as well as at least a portion of the tube that while in operation gets heated to a temperature greater than 1300° F.;
measuring a second set of inside diameters along the predefined length of the reformer tube after operating the reformer tube for an additional period of time, Δt, where t2=t1+Δt;
aligning the second set of diameter measurements using the circumferential reference marking and a second available reference point to ensure that the axial locations of the entire length for the measurements from time t1 are the same as the axial locations of the entire length of the measurements from time t2, and
calculating creep strain along the length of the tube by dividing the difference in diameter measurements at times t1 and t2, by the diameter measurement at time t1, for each location along the length of the tube, thereby determining diametrical growth in a reformer tube.

### Claim 2

A method for determining diametrical growth in a reformer tube comprising:
providing a reformer tube having a circumferential reference marking on the outside of the reformer tube achieved through welding at least one metallic ring on the outer surface of the reformer tube;
measuring a first set of outside diameters at a time t1 along a predefined length of the reformer tube that contains the circumferential reference marking(s) as well as at least a portion of the tube that while in operation gets heated to a temperature greater than 1300° F.;
measuring a second set of outside diameters along the predefined length of the reformer tube after operating the reformer tube for an additional period of time, Δt, where t2=t1+Δt;
aligning the second set of diameter measurements using the circumferential reference marking and a second available reference point to ensure that the axial locations of the entire length for the measurements from time t1 are the same as the axial locations of the entire length of the measurements from time t2; and
calculating creep strain along the length of the tube by dividing the difference in diameter measurements at times t1 and t2, by the diameter measurement at time t1, for each location along the length of the tube, thereby determining diametrical growth in a reformer tube.

### Claim 3 (depends on 1)

A reformer tube according to claim 1.

### Claim 4 (depends on 3)

The reformer tube according to claim 3, wherein the marking of the depth of the circumferential reference marking(s) is larger than the detection limit of the diametrical inspection device.

### Claim 5 (depends on 1)

The marking of claim 1, wherein the circumferential reference marking has a predetermined depth necessary to retain the design minimum sound wall thickness.

### Claim 6 (depends on 1)

The method of claim 1, wherein a diametrical growth measurement is performed through a technique selected from either laser profilometry or stylus based measurements.

### Claim 7 (depends on 1)

The method of claim 1, wherein the diameter growth is determined by automated computational algorithms.

### Claim 8 (depends on 1)

The method of claim 1, wherein the diametrical growth in a reformer tube is measured though the use of a second available reference point, wherein said second reference point is a weld mark.

### Claim 9 (depends on 2)

The method of claim 2, wherein a diametrical growth measurement is performed through a technique selected from either laser profilometry or stylus based measurements.

### Claim 10 (depends on 2)

The method of claim 2, wherein the diametrical growth in a reformer tube is measured though the use of a second available reference point, wherein said second reference point is a weld mark.