Nickel Insitute - Nickel Alloys in Organic Acids & Related Compounds

M. Nickel-Base Molybdenum Alloys Greater attention has been given to this class of alloy for acetic acid exposures in recent years. For most acetic acid applications, the nickel-base iron-chromium-molybdenum- copper alloys are superior to the nickel-base molybdenum alloys without chromium. However, HASTELLOY alloys B and B-2 have good organic acid resistance and have sometimes been used for the distillation of acetic acid mixtures. The cast alloys in this family of alloys include ASTM A 494 grades N-12M-1 and N-12M-2. Trade names associated with these cast grades include CHLORIMET alloy 2 and ILLIUM alloys M1 and M2. These alloys offer excellent corrosion resistance in certain of the newer acetic acid processes utilizing chloride catalysts under reducing conditions at high temperatures. Under these conditions, only zirconium, titanium, and the nickel-base molybdenum alloys appear to be attractive. 16, 17, 18 For the high pressures employed for

Corrosion data for this type of alloy are given in Tables III, VII, XV, XX, XXVII and XXVIII through XXX.

N. Nickel Commercial nickel is less resistant to attack by acetic acid at any temperature than are the nickel-copper alloys, the cupro-nickel alloys, or the austenitic stainless steels. Consequently, nickel as a basic material of construction is not generally used. The material is used as the underbead in the welding of copper-clad steel, being compatible with both the copper and the steel backing. Data showing the resistance of wrought Nickel 200 to acetic acid under varying conditions are contained in Tables III, VII, XIII, XXII, XXIIL XXV, XXVII, XXIX and XXX. The presence of air accentuates the corrosion of nickel. For example, Uhlig reports a rate of attack of .02 mm/y (0.9 mpy) for nickel in a 6% acetic acid solution charged with nitrogen at room temperature, but a rate of .28 mm/y (11 mpy) when air is introduced. 19

the reaction attractive.

area, the use of clad construction is very

TABLE XXVII

Corrosion of Metals and Alloys in Acetaldehyde Oxidation Process for Acetic Acid

Corrosion Rate

Exposure*

1

2

3

4

5

6

7

8

9

10

Alloy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

–

–

–

–

–

–

–

–

–

–

–

–

–

–

0.38

15

–

–

–

–

ACI CF-8 ACI CF-8M ACI CN-7M

– – Nil 0.1 .19 7.5 .06 2.5 .09 3.5 .06 2.4 .02 0.7 .01 0.5 – – Nil Nil 01 0.5 – – .12 4.6 .10 4.1 .11 4.4 .10 3.9 .28 11 – –

–

–

–

–

–

–

–

–

– – Nil 0.1 – – – – .18 7 .03 1 – – Nil Nil .03 1 Nil Nil .03 1 – – – – – – .01 0.3 – – – – – –

– – .02 0.6 – – – – .13 5 .03 1 – – Nil Nil Nil Nil Nil Nil .05 2 – – – – – – .03 1 – –

.03 1 .01 0.4 – – – – .08 3 Nil Nil Nil Nil Nil Nil Nil Nil Nil Nil .18 7 – – – – – – Nil Nil – –

– – .01 0.5 – – – – .03 1 Nil Nil Nil Nil Nil Nil Nil Nil Nil Nil .25 10 – – – – – – Nil Nil – –

–

–

–

–

–

–

–

–

.13

5

–

–

–

–

– – 2.54 100 1.78 70 .33 13 .01 0.5 .18 7 – – .03 1 – – – – .36 14 .86 34 1.12 44 – – – – – –

–

–

–

–

–

–

Type 446 Stainless Steel Type 204 Stainless Steel Type 304 Stainless Steel Type 316 Stainless Steel Type 317 Stainless Steel CARPENTER alloy 20 INCOLOY alloy 825 HASTELLOY alloy C HASTELLOY alloy B HASTELLOY alloy D INCONEL alloy 600 Nickel 200 MONEL alloy 400 EVERDUR 1010 Silicon Bronze Copper DURIRON **

–

–

1.70

67

–

–

–

–

–

–

1.22

48

2.16

85

.25

10

2.34

92

.43 17 .01 0.5 .20 8 – – .03 1 – – – – .23 9 .81 32

.05

2

.01

0.4

–

–

.03

1

Nil

0.2

.89

35

.05

2

Nil

Nil

–

–

–

–

Nil

Nil

.03

1

.03

1

Nil

Nil

.28

11

.23

9

–

–

.1 5

6

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

1.07

42

.94

37

–

–

–

–

–

–

–

–

–

–

– – <.03 < 1

–

–

–

–

– –

–

–

–

–

–

–

–

–

–

–

–

*Exposure 1- Product flash kettle base liquid at 95-100 º C (203-212 º F) for 737 days. Approx. 58% acetic acid, 40% anhydride, 2% residue with peroxides present. 2- Stripping still kettle liquid at 148-150 º C (298-302 º F) for 56 days. Approx. 65% acetic acid, 36% anhydride, residues, peroxides and catalyst salts. 3-

Liquid of stripping still base section at 120 º C (248 º F). 4-Vapor of stripping still base section at 120 º C (248 º F). 5- Liquid of stripping still mid-section. 6-Anhydride still kettle liquid at 145 º C (293 º F). Essentially anhydride. 7- Anhydride still kettle vapor at 145 º C (293 º F). 8-Acetic acid refining still base liquid at 145 º C (293 º F). Mostly anhydride. 9-

Acetic acid refining still base vapor at 145 º C (293 º F). 10-Acetic acid refining still overhead at 120 º C (248 º F).

**Trademark of The Duriron Company, Inc.

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