# US 6,294,387 B1 · Method of determining the corrosiveness of naphthenic acid in crude oil refinery streams

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- Number: US 6,294,387 B1
- Document ID: US6294387B1
- Status: Granted
- Kind: B1
- Application number: 09/275,528
- Filed: 1999-03-24
- Granted: 2001-09-25
- Earliest claimed: 1999-03-24
- Assignees: Intevep, S.A.
- Inventors: Omar Yepez; Jose Vera
- Web page: https://patentgrep.com/patent/US6294387B1

## CPC

- G01N 33/2823: {Raw oil, drilling fluid or polyphasic mixtures}
- 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

A method for determining corrosiveness of naphthenic acid in a fluid includes the steps of: providing a fluid containing naphthenic acid; providing iron powder having a surface area of at least about 0.01 m2/g; contacting the fluid and the powder for a period of time so as to provide a portion of the iron as dissolved iron dissolved in the fluid; and measuring iron concentration of the fluid containing the dissolved iron, so as to provide a measure of corrosion potential of the naphthenic acid over the period of time.

## Claims

### Claim 1

A method for determining corrosiveness of naphthenic acid in a fluid, comprising the steps of:
providing a fluid containing naphthenic acid;
providing iron powder having a surface area of at least about 0.01 m2/g;
contacting said fluid and said powder for a period of time so as to react a portion of said iron with the naphthenic acid to form iron naphthenate which is soluable in said fluid; and
measuring iron concentration of the iron naphthenate in said fluid containing iron, so as to provide a measure of corrosion potential of said naphthenic acid over said period of time.

### Claim 2 (depends on 1)

A method according to claim 1, wherein said iron powder has an average particle size of less than or equal to about 50 μm.

### Claim 3 (depends on 1)

A method according to claim 1, wherein said contacting step comprises contacting said powder and said fluid at a molar ratio of iron to naphthenic acid in said fluid of at least about 1:2.

### Claim 4 (depends on 1)

A method according to claim 1, wherein said contacting step comprises contacting said powder and said fluid at a molar ratio of iron to naphthenic acid in said fluid of at least about 80:1.

### Claim 5 (depends on 1)

A method according to claim 1, wherein said contacting step further provides a remaining portion of said iron as solid non-reacted iron in said fluid, and further comprising the step of removing said solid non-reacted iron before said measuring step.

### Claim 6 (depends on 5)

A method according to claim 5, wherein said step of removing said solid non-reacted iron comprises homogenizing and filtering said fluid whereby said solid non-reacted iron is separated from said fluid.

### Claim 7 (depends on 1)

A method according to claim 1, wherein said contacting step comprises mixing said powder and said fluid so as to provide a substantially homogeneous mixture of said powder and said fluid.

### Claim 8 (depends on 1)

A method according to claim 1, wherein said contacting step is carried out under an inert atmosphere.

### Claim 9 (depends on 1)

A method according to claim 1, wherein said fluid comprises a fluid stream.

### Claim 10 (depends on 1)

A method according to claim 1, wherein said fluid comprises a hydrocarbon.

### Claim 11 (depends on 1)

A method according to claim 1, wherein said fluid is a refinery stream.

### Claim 12 (depends on 11)

A method according to claim 11, wherein said refinery stream is selected from the group consisting of atmospheric distillates, vacuum distillates and mixtures thereof.

### Claim 13 (depends on 1)

A method according to claim 1, wherein said fluid is a crude oil.

### Claim 14 (depends on 13)

A method according to claim 13, wherein said crude oil is selected from the group consisting of heavy oil, light oil and combinations thereof.

### Claim 15 (depends on 1)

A method according to claim 1, wherein said fluid is a 50° C.-500° C. cut from a refinery side stream.

### Claim 16 (depends on 1)

A method according to claim 1, wherein said fluid has a total acid number (TAN) of between about 0 and about 200 mg/KOH/g.

### Claim 17 (depends on 1)

A method according to claim 1, wherein said contacting step is carried out at a known temperature, and said measure of corrosion potential is provided for said known temperature.

### Claim 18 (depends on 1)

A method according to claim 1, wherein said iron powder has a surface area of between about 0.05 and about 2 m2/g.

### Claim 19 (depends on 1)

A method according to claim 1, wherein said powder is present in an amount sufficient to react all of the naphthenic acid in the fluid.