The heater before the reactor in the pilot-scale hydrogenation refining unit is severely corroded

There are quite a few experts in this version, so why isn’t anyone offering advice? Was the information I provided not enough? What more information is needed?

Conditions such as temperature and medium are required! Spraying a high-temperature resistant resin might work

This is typical hydrogen corrosion. There is a problem with the material. Aren’t TP321 and TP347 used? This post was last edited by jessehjx on 2009-4-8 19:31]

Thank you to everyone above; the temperature is 300°C, the pressure is 3.5 Mpa, and it’s a moderate hydrogenation process. I haven’t been given the accident report yet; I only know that it’s stainless steel. Could Jessehjx on the 4th floor explain TP321 and TP347? I come from the field of process development and don’t know much about materials. I hope everyone can offer some advice! Thank you!

Austenitic stainless steel seamless and straight-seam pipes that meet the ASTM A312/A312M-88a standard for austenitic stainless steel seamless and welded pipes, and are suitable for use in high-temperature and generally corrosive environments. Introduction to ASTM A312 Standard 2004-12-14 14:35:00 ASTM A312 is a standard established by the American Society for Testing and Materials regarding welded stainless steel pipes made of austenitic stainless steel. The various parameters for ASTM A312 austenitic stainless steel seamless and welded pipes are as follows:

Item | Standard | Grades
------|----------|--------
TP304 | ASTM A312/A312M |
TP304L | |
TP316 | |
TP316L | |
TP317 | |
TP317L | |
TP347 | |
TP310H* | |
TP321H△ | |

Yield strength σ0.2 (Mpa): ≥170; ≥205
Tensile strength σ0.2 (Mpa): ≥485; ≥515
Elongation σ5 (%): ≥35
Flattening test (mm): H=1.09t/(0.09+t/D), with assessment of integrity
Flaring test
Grain size: *”, “△” – ASTM E112, grade 6# or higher
Hydrostatic test (Mpa): D, Pmax = ASTM A530, D≤270mm, P=2Rt/D, where R=50% σ0.2; ≤88.9 → 17, >88.9 → 19
Corrosion resistance test: ASTM A262, method E (additional requirement)
Non-destructive testing: ASTM E13, E309, E426
Heat treatment: Required

Outer diameter tolerance (mm):
10.3–48.3: +0.40/–0.80
>48.3–114.3: +0.80/–0.08
>114.3–219.1: +1.60/–0.80
>219.1–457.2: +2.40/–0.80
>457.2–660.4: +3.20/–0.80
>660.4–864: +4.00/–0.08
>864–1219.2: +4.80/–0.08

Wall thickness tolerance (mm): +no specification/–12.5%t
Curvature (mm/m): Reasonable straightness

Other requirements: HRB<90

The chemical composition of some austenitic stainless steels per ASTM A312 is as follows:

Grade | UNS Code | Chemical Composition (%)
-------|-----------|-------------------------
Carbon | | Manganese ≤, Phosphorus ≤, Sulfur ≤, Silicon, Nickel, Chromium, Molybdenum, Titanium, Vanadium+Tantalum, Tantalum ≤, Nitrogen, Cobalt, Others
TP304 | S30400 | 0.08max, 2.00, 0.040, 0.030, 0.75max, 8.00–11.00, 18.0–20.0, /, /, /, /, /, /
TP304L | S30403 | 0.035max, 2.00, 0.040, 0.030, 0.75max, 8.00–13.00, 18.0–20.0, /, /, /, /, /, /
TP316 | S31600 | 0.08max, 2.00, 0.040, 0.030, 0.75max, 11.00–14.00, 16.00–18.00, 2.0–3.0, /, /, /, /, /, /
TP316L | S31603 | 0.035maxB, 2.00, 0.040, 0.030, 0.75max, 10.00–15.00, 16.00–18.00, 2.0–3.0, /, /, /, /, /, /
TP321 | S32100 | 0.08max, 2.00, 0.040, 0.030, 0.75max, 9.00–13.00, 17.00–20.00, /, D / / / / /

Who can provide a comprehensive overview of the requirements regarding materials and welding in hydrorefining?

Hydrogen embrittlement corrosion cracks should be forming. In high-temperature hydrogen-exposed equipment as well as equipment in contact with aqueous hydrogen sulfide solutions, there are processes involving the introduction of hydrogen or its release, which can cause hydrogen-induced damage to the equipment. The types of hydrogen-induced damage include hydrogen blistering: hydrogen atoms penetrate into the steel, and where they encounter cracks, inclusions, and voids within the steel, they gather together to form hydrogen molecules; this leads to an increase in volume and pressure, resulting in blistering of the steel. Hydrogen bubbling can be prevented by using clean steel free from inclusions or stratification. Hydrogen embrittlement is a phenomenon in which hydrogen itself causes steel to become brittle. When hydrogen atoms penetrate into steel, they reduce the bonding strength between the steel grains, resulting in a decrease in the elongation and reduction of area of the steel, or leading to delayed failure. If hydrogen is released from the steel, its mechanical properties can still be restored. Hydrogen embrittlement is temporary, and it can be eliminated by heating the steel. Surface decarburization occurs when steel comes into contact with high-temperature hydrogen. Surface decarburization does not cause cracks; its effect is a slight decrease in strength and hardness, along with an increase in elongation. Hydrogen corrosion (internal decarburization) occurs when hydrogen penetrates the steel under high temperature and pressure, leading to the formation of methane from unstable carbides. Methane in steel does not easily escape, causing cracks and bubbling in the steel, as well as a significant reduction in its strength and toughness. Its corrosion reaction is irreversible, resulting in permanent embrittlement. To prevent surface decarburization and internal decarburization, it is necessary to select carbon steel or chromium-molybdenum steel appropriately according to the \"Nelson curve\".

Hydrogen embrittlement and hydrogen corrosion are primarily related to the operating temperature and hydrogen partial pressure; by referring to the Nelson curve based on the operating conditions (temperature of 300°C and pressure of 3.5 Mpa), it can be determined that the appropriate material is 15CrMoR (previously designated as 1Cr-0.5Mo). Industrial hydrocracking reactors have higher temperatures and pressures, and 12Cr 2Mo 1R (previously designated as 2.25Cr-1Mo) is commonly used.

I just received two pieces of information today: one is that our material is 316 stainless steel, and the other is that the heating element that suffers from corrosion is filled with a heating medium on the inside, while on the outside, the side that experiences corrosion is in contact with crude oil and hydrogen. Sometimes, the temperature of the oil entering the heater is several degrees below zero; as a result, there is a very large temperature difference between the hot and cold sides, of around two to three hundred degrees. Could this lead to the cracking of the heating element due to thermal expansion and contraction?