The characteristics of HCI are similar to those of dry CI. There is also a critical temperature that causes the corrosion rate of metal materials to increase sharply. For some corrosion test data, see Table 2-27, Table 2-28, and Table 2-29. Combining these corrosion data, it can be considered that pure nickel and NiAl4 containing 4% Al have the best corrosion resistance in high-temperature HCI gas. In this high-temperature gas, Monel 400 and stainless steel do not have suitable corrosion resistance. During the chemical process using high-temperature HCI gas, avoid HCI condensation in the equipment or process piping. Failure to do so will result in severe corrosion of the equipment and piping materials by the HCI acid formed by condensation of HCI gas.
2-27 Corrosion of Some Metallic Materials in Dry HCI
|
Grade |
Short-term experiments in dry HCI with corrosion rates exceeding the approximate temperatures for a given corrosion rate |
Temperatue /ºC |
||
|
0.76mm/a |
1.52mm/a |
3.05mm/a |
||
|
Ni201 |
454 |
510 |
565 |
510 |
|
600 |
426 |
482 |
538 |
482 |
|
C-276 |
371 |
426 |
482 |
452 |
|
316 stainless steel |
371 |
371 |
482 |
426 |
|
304 stainless steel |
343 |
399 |
454 |
399 |
|
Carbon |
260 |
315 |
399 |
260 |
|
Monel 400 |
232 |
260 |
343 |
232 |
|
Cu |
93 |
149 |
204 |
93 |
|
Grade |
Short-term experiments in dry HCI with corrosion rates exceeding the approximate temperatures for a given corrosion rate |
Temperatue /ºC |
||
|
0.76mm/a |
1.52mm/a |
3.05mm/a |
||
|
Ni201 |
454 |
510 |
565 |
510 |
|
600 |
426 |
482 |
538 |
482 |
|
C-276 |
371 |
426 |
482 |
452 |
|
316 stainless steel |
371 |
371 |
482 |
426 |
|
304 stainless steel |
343 |
399 |
454 |
399 |
|
Carbon |
260 |
315 |
399 |
260 |
|
Monel 400 |
232 |
260 |
343 |
232 |
|
Cu |
93 |
149 |
204 |
93 |
2-28 Corrosion of Some Nickel Base Alloys and Stainless Steels in Anhydrous HCI
|
Grade |
Temperature/ºC |
time/h |
corrosion average rate/ mm﹒a⁻¹ |
|
Ni201 |
498 |
50 |
0.08 |
|
600 |
498 |
500 |
0.08 |
|
304 stainless steel |
498 |
500 |
0.26 |
2-29 Corrosion Test Results of Nickel-based Corrosion Resistant Alloys in High-temperature HCI Gas 96
|
Grade |
400ºC |
450ºC |
||
|
corrosion average rate/ g﹒(m²﹒h)⁻¹ |
Intergranular corrosion |
corrosion average rate/ g﹒(m²﹒h)⁻¹ |
Intergranular corrosion |
|
|
Ni200 |
0.097~0.152 |
none |
0.109~0.249 |
have |
|
high purity Ni |
0.075 |
none |
0.129~0.343 |
have |
|
monel 400 |
0.37 |
/ |
1.372 |
none |
|
NiAl₄+Ce |
0.063 |
none |
0.111 |
none |
|
NiAl₄ |
0.108 |
none |
0.164 |
none |
|
NS 3301 |
0.222 |
/ |
/ |
/ |
|
NS 1401 |
0.216 |
/ |
/ |
/ |
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Post time: May-11-2018